10,283 research outputs found
Quasideuteron states with deformed core
The M1 transitions between low-lying T=1 and T=0 states in deformed odd-odd
N=Z nuclei are analyzed in the frames of the rotor-plus-particle model. Using
the representation of an explicit coupling of angular momenta we show that
strong coupling of the quasideuteron configurations to the axially deformed
core results in a distribution of the total 0+ --> 1+ strength among a few
low-lying 1+ states. Simple analytical formulae for B(M1) values are derived.
The realization of the M1 sum rule for the low-lying 1+,T=0 states is
indicated. The calculated B(M1) values are found to be in good agreement with
experimental data and reveal specific features of collectivity in odd-odd N=Z
nuclei.Comment: 11 pages, 1 figure, LaTe
Solar neutrinos: global analysis with day and night spectra from SNO
We perform global analysis of the solar neutrino data including the day and
night spectra of events at SNO. In the context of two active neutrino mixing,
the best fit of the data is provided by the LMA MSW solution with Delta m^2 =
6.15 10^{-5} eV^2, tan^2\theta = 0.41, f_B = 1.05, where f_B is the boron
neutrino flux in units of the corresponding flux in the Standard Solar Model
(SSM). At 3 sigma level we find the following upper bounds: tan^2\theta < 0.84
and Delta m^2 < 3.6 10^{-4} eV^2. From 1 sigma-interval we expect the day-night
asymmetries of the charged current and electron scattering events to be:
A_{DN}^{CC} = 3.9 +3.6-2.9 and A_{DN}^{ES} = 2.1 +2.1-1.4. The only other
solution which appears at 3 sigma-level is the VAC solution with Delta m^2 =
4.5 10^{-10} eV^2, tan^2\theta = 2.1 and f_B=0.75. The best fit point in the
LOW region, with Delta m^2 = 0.93 10^{-7} eV^2 and tan^2\theta = 0.64, is
accepted at 99.95% (3.5 sigma) C.L. . The least chi^2 point from the SMA
solution region, with Delta m^2 = 4.6 10^{-6} eV^2 and tan^2\theta = 5 10^{-4},
could be accepted at 5.5 sigma-level only. In the three neutrino context the
influence of theta_{13} is studied. We find that with increase of theta_{13}
the LMA best fit point shifts to larger Delta m^2, mixing angle is practically
unchanged, and the quality of the fit becomes worse. The fits of LOW and SMA
slightly improve. Predictions for KamLAND experiment (total rates, spectrum
distortion) have been calculated.Comment: Typos corrected, reference adde
Origin of the giant magnetic moments of Fe impurities on and in Cs films
To explore the origin of the observed giant magnetic moments ()
of Fe impurities on the surface and in the bulk of Cs films, we have performed
the relativistic LSDA + U calculations using the linearized muffin-tin orbital
(LMTO) band method. We have found that Fe impurities in Cs behave differently
from those in noble metals or in Pd. Whereas the induced spin polarization of
Cs atoms is negligible, the Fe ion itself is found to be the source of the
giant magnetic moment. The 3d electrons of Fe in Cs are localized as the 4f
electrons in rare-earth ions so that the orbital magnetic moment becomes as
large as the spin magnetic moment. The calculated total magnetic moment of , which comes mainly from Fe ion, is close to the experimentally
observed value.Comment: 4 pages including 3 figures and 1 table. Submitted to PR
Directional wetting in anisotropic inverse opals
Porous materials display interesting transport phenomena due to the restricted motion of fluids within the nano- to micro-scale voids. Here, we investigate how liquid wetting in highly ordered inverse opals is affected by anisotropy in pore geometry. We compare samples with different degrees of pore asphericity and find different wetting patterns depending on the pore shape. Highly anisotropic structures are infiltrated more easily than their isotropic counterparts. Further, the wetting of anisotropic inverse opals is directional, with liquids filling from the side more easily. This effect is supported by percolation simulations as well as direct observations of wetting using time-resolved optical microscopy
Testing the solar LMA region with KamLAND data
We investigate the potential of 3 kiloTon-years(kTy) of KamLAND data to
further constrain the and values compared to those
presently allowed by existing KamLAND and global solar data. We study the
extent, dependence and characteristics of this sensitivity in and around the
two parts of the LMA region that are currently allowed. Our analysis with 3 kTy
simulated spectra shows that KamLAND spectrum data by itself can constrain
with high precision. Combining the spectrum with global solar data
further tightens the constraints on allowed values of and
. We also study the effects of future neutral current data with a
total error of 7% from the Sudbury Neutrino Observatory. We find that these
future measurements offer the potential of considerable precision in
determining the oscillation parameters (specially the mass parameter).Comment: 16 pages, to appear in J Phys.
CO Detection and Millimeter Continuum Emission from Low Surface Brightness Galaxies
We present BIMA and IRAM CO(1--0) observations of seven low surface brightness (LSB) galaxies, including three large spirals with faint disks but prominent bulges, and four relatively small LSB galaxies with irregular disks. The giant LSB galaxies are UGC 5709, UGC 6614 and F568-6 (Malin2). The smaller LSB galaxies are NGC 5585, UGC 4115, UGC 5209 and F583-1. The galaxies were selected based on their relatively high metallicity and apparent signs of star formation in their disks. The BIMA maps suggested the presence of molecular gas in 2 of the giant LSB galaxies, F568-6 and UGC 6614. Using the 30m IRAM telescope we detected CO (1--0) emission in the disks of both galaxies and in the nucleus of F568-6. The molecular gas in these galaxies is clearly offset from the nucleus and definitely associated with the LSB disk. In addition we also detected a millimeter continuum source in the center of UGC 6614. When compared with VLA 1.5 GHz observations of the galaxy, the emission was found to have a flat spectrum indicating that the millimeter continuum emission is most likely due to an active galactic nucleus (AGN) in the galaxy. Our results show that giant LSB spirals may contain significant quantities of molecular gas in their disks and also harbor radio bright AGN in their centers
The atmospheric neutrino anomaly without maximal mixing?
We consider a pattern of neutrino masses in which there is an approximate
mass degeneracy between the two mass eigenstates most coupled to the
and flavour eigenstates. Earth-matter effects can lift this
degeneracy and induce an effectively maximal mixing between these two
generations. This occurs if 's contain comparable admixtures of the
degenerate eigenstates, even rather small ones. This provides an explanation of
the atmospheric neutrino anomaly in which the {\it ab initio} introduction of a
large mixing angle is not required. To test this possibility we perform a novel
and detailed analysis of the 52 kiloton-year SuperKamiokande data, and we find
that in a large region of parameter space the corresponding confidence levels
are excellent. The most recent results from the Chooz reactor experiment,
however, severely curtail this region, so that the conventional scenario with
nearly maximal mixing angles --which we also analyse in detail-- is supported
by the data.Comment: Some relevant references added and a misprint correcte
Sialome of a Generalist Lepidopteran Herbivore: Identification of Transcripts and Proteins from Helicoverpa armigera Labial Salivary Glands
Although the importance of insect saliva in insect-host plant interactions has been acknowledged, there is very limited information on the nature and complexity of the salivary proteome in lepidopteran herbivores. We inspected the labial salivary transcriptome and proteome of Helicoverpa armigera, an important polyphagous pest species. To identify the majority of the salivary proteins we have randomly sequenced 19,389 expressed sequence tags (ESTs) from a normalized cDNA library of salivary glands. In parallel, a non-cytosolic enriched protein fraction was obtained from labial salivary glands and subjected to two-dimensional gel electrophoresis (2-DE) and de novo peptide sequencing. This procedure allowed comparison of peptides and EST sequences and enabled us to identify 65 protein spots from the secreted labial saliva 2DE proteome. The mass spectrometry analysis revealed ecdysone, glucose oxidase, fructosidase, carboxyl/cholinesterase and an uncharacterized protein previously detected in H. armigera midgut proteome. Consistently, their corresponding transcripts are among the most abundant in our cDNA library. We did find redundancy of sequence identification of saliva-secreted proteins suggesting multiple isoforms. As expected, we found several enzymes responsible for digestion and plant offense. In addition, we identified non-digestive proteins such as an arginine kinase and abundant proteins of unknown function. This identification of secreted salivary gland proteins allows a more comprehensive understanding of insect feeding and poses new challenges for the elucidation of protein function
- …