23,356 research outputs found
CIRCULAR DICHROISM OF LIGHT-HARVESTING COMPLEXES FROM PURPLE PHOTOSYNTHETIC BACTERIA
The CD spectra of a range of antenna complexes from several different species of purple photosynthetic bacteria were recorded in the wavelength range of 190 to 930 nm. Analysis of the far UV CD (190 to 250 nm) showed that in each case except for the B800-850 from Chr. vinosum the secondary structure of the light-harvesting complexes contains a large amount of α-helix (50%) and very little 0-pleated sheet. This confirms the predictions of the group of Zuber of a high a-helical content based upon consideration of the primary structures of several antenna apoproteins. The CD spectra from the carotenoids and the bacteriochlorophylls show considerable variations depending upon the type of antenna complex. The different amplitude ratios in the CD spectrum for the bacteriochlorophyll Qy, Qx and Soret bands indicate not only different degrees of exciton coupling, but also a strong and variable hyperchromism (Scherz and Parson, 1984a, b)
Asymptotic estimation theory for a finite dimensional pure state model
The optimization of measurement for n samples of pure sates are studied. The
error of the optimal measurement for n samples is asymptotically compared with
the one of the maximum likelihood estimators from n data given by the optimal
measurement for one sample.Comment: LaTeX, 23 pages, Doctoral Thesi
Characteristics of central collision events in Fe-nucleus interactions for 20 - 60 GeV/nucleon
A counter emulsion hybrid chamber in Japanese-American Cooperative Emulsion Experiment (JACEE-3) was flown on a balloon at the altitude (5.4 g/sq cm) in 1982 with the objective of probing the heavy nuclear collisions above 20 GeV per nucleon. In the energy region, it is suggested that nucleus-nucleus collisions provide dense collisions complex through compression and secondary particle production. In the lower energy region, an evidence of collective flow has been reported. And also, at higher energy region, it has been argued that nucleus has rather large stopping power. In this paper, the high multiplicity characteristics of Fe nucleus central collisions with energies 20 to 50 GeV/nucleon are presented. This is considered to be relevant to compressibility and collective flow of nuclear matter
Two quantum analogues of Fisher information from a large deviation viewpoint of quantum estimation
We discuss two quantum analogues of Fisher information, symmetric logarithmic
derivative (SLD) Fisher information and Kubo-Mori-Bogoljubov (KMB) Fisher
information from a large deviation viewpoint of quantum estimation and prove
that the former gives the true bound and the latter gives the bound of
consistent superefficient estimators. In another comparison, it is shown that
the difference between them is characterized by the change of the order of
limits.Comment: LaTeX with iopart.cls, iopart12.clo, iopams.st
Dilatonic Inflation and SUSY Breaking in String-inspired Supergravity
The theory of inflation will be investigated as well as supersymmetry
breaking in the context of supergravity, incorporating the target-space duality
and the nonperturbative gaugino condensation in the hidden sector. We found an
inflationary trajectory of a dilaton field and a condensate field which breaks
supersymmetry at once. The model satisfies the slow-roll condition which solves
the eta-problem. When the particle rolls down along the minimized trajectory of
the potential V(S,Y) at a duality invariant point of T=1, we can obtain the
e-fold value \sim 57. And then the cosmological parameters obtained from our
model well match the recent WMAP data combined with other experiments. This
observation suggests one to consider the string-inspired supergravity as a
fundamental theory of the evolution of the universe as well as the particle
theory.Comment: 10 pages, 4 eps figures. Typos and references corrected. Final
version to appear in Mod. Phys. Lett.
Process for the production of metal nitride sintered bodies and resultant silicon nitride and aluminum nitride sintered bodies
A process for the manufacture of metal nitride sintered bodies, in particular, a process in which a mixture of metal nitrite powders is shaped and heated together with a binding agent is described. Of the metal nitrides Si3N4 and AIN were used especially frequently because of their excellent properties at high temperatures. The goal is to produce a process for metal nitride sintered bodies with high strength, high corrosion resistance, thermal shock resistance, thermal shock resistance, and avoidance of previously known faults
Primary cosmic ray spectra in the range 20-60 GeV/n
Energy spectra for primary cosmic rays C-Fe above 20 GeV/n were measured on a balloon flight from Greenville S.C. in June 1982 with a hybrid electronic counter-emulsion chamber experiment. Fluxes above the atmosphere appear in general agreement with previously published values. The heavy events included in this data will be used along with the JACEE passive chamber data to provide a heavy composition direct measurement from 10 to the 12th power to approximately 10 to the 15th power eV total energy
The response of a scintillation counter below an emulsion chamber to heavy nucleus interactions in the chamber
In 1982 a hybrid electronic counter-emulsion chamber experiment was flown on a balloon to study heavy nucleus interactions in the 20 to approximately 100 GeV/AMU energy range. A gas Cerenkov counter, two solid Cerenkov counters, and a proportional counter hodoscope gave the primary energy, the primary charge and the trajectory of the particles, respectively. Using the trajectory information cosmic ray nuclei of Z 10 were found reliably and efficiently, and interaction characteristics of the Fe group nuclei were measured in the chamber. A plastic scintillator below the emulsion chamber responded to showers resulting from interactions in the chamber and to noninteracting nuclei. Data on the response of the counter have been compared with simulations of hadronic-electromagnetic cascades to derive the average neutral energy fraction released by the heavy interactions, and to predict the performance of this kind of counter at higher energies. For the interacting events of highest produced particles multiplicity comparison between various simulations and the shower counter signal have been made
Mass and Gas Profiles in A1689: Joint X-ray and Lensing Analysis
We carry out a comprehensive joint analysis of high quality HST/ACS and
Chandra measurements of A1689, from which we derive mass, temperature, X-ray
emission and abundance profiles. The X-ray emission is smooth and symmetric,
and the lensing mass is centrally concentrated indicating a relaxed cluster.
Assuming hydrostatic equilibrium we deduce a 3D mass profile that agrees
simultaneously with both the lensing and X-ray measurements. However, the
projected temperature profile predicted with this 3D mass profile exceeds the
observed temperature by ~30% at all radii, a level of discrepancy comparable to
the level found for other relaxed clusters. This result may support recent
suggestions from hydrodynamical simulations that denser, more X-ray luminous
small-scale structure can bias observed temperature measurements downward at
about the same (~30%) level. We determine the gas entropy at 0.1r_{vir} (where
r_{vir} is the virial radius) to be ~800 keV cm^2, as expected for a high
temperature cluster, but its profile at >0.1r_{vir} has a power-law form with
index ~0.8, considerably shallower than the ~1.1 index advocated by theoretical
studies and simulations. Moreover, if a constant entropy ''floor'' exists at
all, then it is within a small region in the inner core, r<0.02r_{vir}, in
accord with previous theoretical studies of massive clusters.Comment: 18 pages, 20 figures, 7 tables, accepted for publication in MNRAS,
minor changes to match published versio
- …