1,719 research outputs found
Hexadecapole Interaction and the Delta I=4 Staggering Effect in Rotational Bands
A role of the multipole interaction in the description of the =4
staggering phenomenon is investigated in a model consisting of a single-
shell filled by identical nucleons. Exact diagonalization of the
quadrupole-plus-hexadecapole Hamiltonian shows that the
hexadecapole-hexadecapole interaction can produce a =4 periodicity
in the yrast sequence.Comment: revised version with technical changes only, to be published in
Physica Scripta, latex, 4 pages, 3 PostScript figures available on request
from [email protected], preprint No. IFT/18/9
Recommended from our members
Quantifying lung ultrasound comets with a convolutional neural network: Initial clinical results
Lung ultrasound comets are "comet-tail" artifacts appearing in lung ultrasound images. They are particularly useful in detecting several lung pathologies and may indicate the amount of extravascular lung water. However, the comets are not always well defined and large variations in the counting results exist between observers. This study uses a convolutional neural network to quantify these lung ultrasound comets on a 4864-image clinical lung ultrasound dataset labeled by the authors. The neural network counted the number of comets correctly on 43.4% of the images and has an intraclass correlation (ICC) of 0.791 with respect to human counting on the test set. The ICC level indicates a higher correlation level than previously reported ICC between human observers. The neural network was then deployed and applied to a clinical 6272-image dataset. The correlation between the automated comet counts and the clinical parameters was examined. The comet counts correlate positively with the diastolic blood pressure (pâŻ=âŻ0.047, râŻ=âŻ0.448), negatively with ejection fraction (pâŻ=âŻ0.061, râŻ=âŻ-0.513), and negatively with BMI (pâŻ=âŻ0.009, râŻ=âŻ-0.566). The neural network can be alternatively formulated as a diagnostic test for comet-positive images with 80.8% accuracy. The results could potentially be improved with a larger dataset and a refined approach to the neural networks used
Mitochondrial genomes of the key zooplankton copepods Arctic Calanus glacialis and North Atlantic Calanus finmarchicus with the longest crustacean non-coding regions
We determined the nearly complete mitochondrial genomes of the Arctic Calanus glacialis and its North Atlantic sibling Calanus finmarchicus, which are key zooplankton components in marine ecosystems. The sequenced part of C. glacialis mitogenome is 27,342 bp long and consists of two contigs, while for C. finmarchicus it is 29,462 bp and six contigs, what makes them the longest reported copepod mitogenomes. The typical set of metazoan mitochondrial genes is present in these mitogenomes, although the non-coding regions (NCRs) are unusually long and complex. The mitogenomes of the closest species C. glacialis and C. finmarchicus, followed by the North Pacific C. sinicus, are structurally similar and differ from the much more typical of deep-water, Arctic C. hyperboreus. This evolutionary trend for the expansion of NCRs within the Calanus mitogenomes increases mitochondrial DNA density, what resulted in its similar density to the nuclear genome. Given large differences in the length and structure of C. glacialis and C. finmarchicus mitogenomes, we conclude that the species are genetically distinct and thus cannot hybridize. The molecular resources presented here: the mitogenomic and rDNA sequences, and the database of repetitive elements should facilitate the development of genetic markers suitable in pursuing evolutionary research in copepods.Polish Ministry of Science and Higher Education [Iuventus Plus] [IP2014 050573]; FCT-CCMAR Portugal [Multi/04326/2013
Vibrationally Resolved Decay Width of Interatomic Coulombic Decay in HeNe
We investigate the ionization of HeNe from below the He 1s3p excitation to
the He ionization threshold. We observe HeNe ions with an enhancement by
more than a factor of 60 when the He side couples resonantly to the radiation
field. These ions are an experimental proof of a two-center resonant
photoionization mechanism predicted by Najjari et al. [Phys. Rev. Lett. 105,
153002 (2010)]. Furthermore, our data provide electronic and vibrational state
resolved decay widths of interatomic Coulombic decay (ICD) in HeNe dimers. We
find that the ICD lifetime strongly increases with increasing vibrational
state.Comment: 7 pages, 5 figure
Generator Coordinate Truncations
We investigate the accuracy of several schemes to calculate ground-state
correlation energies using the generator coordinate technique. Our test-bed for
the study is the interacting boson model, equivalent to a 6-level
Lipkin-type model. We find that the simplified projection of a triaxial
generator coordinate state using the subgroup of the rotation group is
not very accurate in the parameter space of the Hamiltonian of interest. On the
other hand, a full rotational projection of an axial generator coordinate state
gives remarkable accuracy. We also discuss the validity of the simplified
treatment using the extended Gaussian overlap approximation (top-GOA), and show
that it works reasonably well when the number of boson is four or larger.Comment: 19 pages, 6 eps figure
Analytical and Biological Characterization of Supercoiled Plasmids Purified by Various Chromatographic Techniques
This is the publisher's version, also available electronically from http://online.liebertpub.com/doi/abs/10.1089/dna.2005.24.819Supercoiled plasmids are an important component of gene-based delivery vehicles. A number of production methods for clinical applications have been developed, each resulting in very high-quality product with low levels of residual contaminants. There is, however, no consensus on the optimal methods to characterize plasmid quality, and further, to determine if these methods are predictive of either product stability or biological activity. We have produced two plasmids using four production purification methodologies based on PolyFloŸ and hydrophobic interaction chromatography (HIC), either alone or in tandem processes. In each case, the product was analyzed using standard molecular biological methods. We also performed a number of biophysical analyses such as dynamic light scattering (DLS), circular dichroism (CD), Fourier transform infrared spectroscopy (FTIR), and differential scanning calorimetry (DSC). Minimal differences were detected among the preparations based on the more standard molecular biological methods. Some small differences were detected, however, using biophysical techniques, particularly FTIR and DSC, which may reflect small variations in plasmid tertiary structure and thermal stability. Stability after heat exposure at 60°C, exposure to fetal bovine serum and long-term storage at 4°C varied between plasmids. One plasmid showed no difference in stability depending on the production process, but the other showed significant differences. Evaluation in vivo in models for gene immunization and gene therapy showed significant differences in the response depending on the method of purification. Preparations using a tandem process of PolyFlo used in two separation modes provided higher biological activity compared to a tandem HIC/PolyFlo process or either resin used alone in a single column process. These data indicate that the process by which supercoiled plasmids are made can influence plasmid stability and biological activity and emphasize the need for more rigorous methods to evaluate supercoiled plasmids as gene-delivery vehicles
Peripheral N Scattering: A Tool For Identifying The Two Pion Exchange Component Of The NN Potential
We study elastic N scattering and produce a quantitative correlation
between the range of the effective potential and the energy of the system. This
allows the identification of the waves and energies for which the scattering
may be said to be peripheral. We then show that the corresponding phase shifts
are sensitive to the tail of the NN potential, which is due to the exchange of
two pions. However, the present uncertainties in the experimental phase shifts
prevent the use of N scattering to discriminate the existing models
for the NN interaction.Comment: 19 pages, 6 PostScript figures, RevTeX, to be appear in Phys. Rev.
Pericentrosomal targeting of Rab6 secretory vesicles by Bicaudal-D-related protein 1 (BICDR-1) regulates neuritogenesis
Membrane and secretory trafficking are essential for proper neuronal development. However, the molecular mechanisms that organize secretory trafficking are poorly understood. Here, we identify Bicaudal-D-related protein 1 (BICDR-1) as an effector of the small GTPase Rab6 and key component of the molecular machinery that controls secretory vesicle transport in developing neurons. BICDR-1 interacts with kinesin motor Kif1C, the dynein/dynactin retrograde motor complex, regulates the pericentrosomal localization of Rab6-positive secretory vesicles and is required for neural development in zebrafish. BICDR-1 expression is high during early neuronal development and strongly declines during neurite outgrowth. In young neurons, BICDR-1 accumulates Rab6 secretory vesicles around the centrosome, restricts anterograde secretory transport and inhibits neuritogenesis. Later during development, BICDR-1 expression is strongly reduced, which permits anterograde secretory transport required for neurite outgrowth. These results indicate an important role for BICDR-1 as temporal regulator of secretory trafficking during the early phase of neuronal differentiation
Alpha scattering and capture reactions in the A = 7 system at low energies
Differential cross sections for He- scattering were measured in
the energy range up to 3 MeV. These data together with other available
experimental results for He and H scattering were
analyzed in the framework of the optical model using double-folded potentials.
The optical potentials obtained were used to calculate the astrophysical
S-factors of the capture reactions HeBe and
HLi, and the branching ratios for the transitions into
the two final Be and Li bound states, respectively. For
HeBe excellent agreement between calculated and
experimental data is obtained. For HLi a value
has been found which is a factor of about 1.5 larger than the adopted value.
For both capture reactions a similar branching ratio of has been obtained.Comment: submitted to Phys.Rev.C, 34 pages, figures available from one of the
authors, LaTeX with RevTeX, IK-TUW-Preprint 930540
Hirschsprung disease, associated syndromes and genetics: A review
Hirschsprung disease (HSCR, aganglionic megacolon) represents the main genetic cause of functional intestinal obstruction with an incidence of 1/5000 live births. This developmental disorder is a neurocristopathy and is characterised by the absence of the enteric ganglia along a variable length of the intestine. In the last decades, the development of surgical approaches has importantly decreased mortality and morbidity which allowed the emergence of familial cases. Isolated HSCR appears to be a non-Mendelian malformation with low, sex-dependent penetrance, and variable expression according to the length of the aganglionic segment. While all Mendelian modes of inheritance have been described in syndromic HSCR, isolated HSCR stands as a model for genetic disorders with complex patterns of inheritance. The tyrosine kinase receptor RET is the major gene with both rare coding sequence mutations and/or a frequent variant located in an enhancer element predisposing to the disease. Hitherto, 10 genes and five loci have been found to be involved in HSCR development.published_or_final_versio
- âŠ