352 research outputs found
Cross-Document Pattern Matching
We study a new variant of the string matching problem called cross-document
string matching, which is the problem of indexing a collection of documents to
support an efficient search for a pattern in a selected document, where the
pattern itself is a substring of another document. Several variants of this
problem are considered, and efficient linear-space solutions are proposed with
query time bounds that either do not depend at all on the pattern size or
depend on it in a very limited way (doubly logarithmic). As a side result, we
propose an improved solution to the weighted level ancestor problem
Transition rates and nuclear structure changes in mirror nuclei 47Cr and 47V
Lifetime measurements in the mirror nuclei 47Cr and 47V were performed by
means of the Doppler-shift attenuation method using the multidetector array
EUROBALL, in conjunction with the ancillary detectors ISIS and the Neutron
Wall. The determined transition strengths in the yrast cascades are well
described by full pf shell model calculations.Comment: Latex2e, 11 pages, 3 figure
Breastfeeding modifies the impact of diarrhoeal disease on relative weight: a longitudinal analysis of 2–12 month-old Filipino infants
Undernutrition and diarrhoeal disease are major causes of infant mortality. We investigated the combined roles of breastfeeding and diarrhoea on infant size in 2940 infants from the Cebu Longitudinal Health and Nutrition Survey. The study aimed to assess whether breastfeeding status modified the deficits associated with diarrhoeal disease. The primary exposures were combinations of current breastfeeding status (yes/no), the presence of diarrhoeal disease in previous week (yes/no) and a categorical survey variable (six surveys taken at bimonthly intervals when infants were 2–12 months of age). Relative weight (weight-for-length z-scores), calculated using the WHO growth standards, was estimated using sex-stratified, fixed-effects longitudinal models that also adjusted for energy from complementary foods. Post-estimation Wald tests were conducted to identify subgroup differences in relative weight. Diarrhoea was associated with reduced relative weight in both breastfed and non-breastfed infants of 6–12 months. Diarrhoea-related deficits in relative weight were significantly exacerbated in non-breastfed girls of 6 and 8 months. Importantly, in infants <6 months, being breastfed and having diarrhoea was still associated with greater relative weight compared with being non-breastfed and diarrhoea-free. Breastfeeding emerged as a strong contributor to relative weight in younger infants (<6 months) while diarrhoeal disease strongly contributed to deficits in relative weight in older infants (6–12 months). These findings underscore the importance of breastfeeding for promoting infant nutritional status in infants with or without diarrhoea from birth to 12 months
Description of superdeformed nuclei in the interacting boson model
The interacting boson model is extended to describe the spectroscopy of
superdeformed bands. Microscopic structure of the model in the second minimum
is discussed and superdeformed bosons are introduced as the new building
blocks. Solutions of a quadrupole Hamiltonian are implemented through the
expansion method. Effects of the quadrupole parameters on dynamic moment of
inertia and electric quadrupole transition rates are discussed and the results
are used in a description of superdeformed bands in the Hg-Pb and Gd-Dy
regions.Comment: 18 pages revtex, 9 figures available upon reques
Mirror Energy Differences at Large Isospin Studied through Direct Two-Nucleon Knockout
The first spectroscopy of excited states in Ni52 (Tz=-2) and Co51 (Tz=-3/2) has been obtained using the highly selective two-neutron knockout reaction. Mirror energy differences between isobaric analogue states in these nuclei and their mirror partners are interpreted in terms of isospin nonconserving effects. A comparison between large-scale shell-model calculations and data provides the most compelling evidence to date that both electromagnetic and an additional isospin nonconserving interactions for J=2 couplings, of unknown origin, are required to obtain good agreement. � 2013 American Physical Society
Mirrored one-nucleon knockout reactions to the T-z = +/- 3/2 A=53 mirror nuclei
Background: The study of excited states in mirror nuclei allows us to extract information on charge-dependent (i.e., isospin-nonconserving) interactions in nuclei.
Purpose: To extend previous studies of mirror nuclei in the f72 region, investigating charge symmetry breaking of the strong nuclear force.
Methods: γ-ray spectroscopy has been performed for the mirror (Tz=±32) pair Ni53 and Mn53, produced via mirrored one-nucleon knockout reactions.
Results: Several new transitions have been identified in Ni53 from which a new level scheme has been constructed. Cross sections for knockout have been analyzed and compared with reaction model calculations where evidence is found for knockout from high-spin isomeric states. Mirror energy differences between isobaric analog states have been computed, compared to large scale shell-model calculations, and interpreted in terms of isospin-nonconserving effects. In addition, lifetimes for the long-lived Jπ=52−1 analog states in both Mn53 and Ni53 have been extracted through lineshape analysis, giving half-lives of t12=120(14) ps and t12=198(12) ps, respectively.
Conclusions: The inclusion of a set of isovector isospin-nonconserving matrix elements to the shell-model calculations gave the best agreement with the experimental data
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