488 research outputs found
On Words with the Zero Palindromic Defect
We study the set of finite words with zero palindromic defect, i.e., words
rich in palindromes. This set is factorial, but not recurrent. We focus on
description of pairs of rich words which cannot occur simultaneously as factors
of a longer rich word
Observation of isotonic symmetry for enhanced quadrupole collectivity in neutron-rich 62,64,66Fe isotopes at N=40
The transition rates for the 2_{1}^{+} states in 62,64,66Fe were studied
using the Recoil Distance Doppler-Shift technique applied to projectile Coulomb
excitation reactions. The deduced E2 strengths illustrate the enhanced
collectivity of the neutron-rich Fe isotopes up to N=40. The results are
interpreted by the generalized concept of valence proton symmetry which
describes the evolution of nuclear structure around N=40 as governed by the
number of valence protons with respect to Z~30. The deformation suggested by
the experimental data is reproduced by state-of-the-art shell calculations with
a new effective interaction developed for the fpgd valence space.Comment: 4 pages, 2 figure
Translation in Bacillus subtilis is spatially and temporally coordinated during sporulation
The transcriptional control of sporulation in Bacillus subtilis is reasonably well understood, but its translational control is underexplored. Here, we use RNA-seq, ribosome profiling and fluorescence microscopy to study the translational dynamics of B. subtilis sporulation. We identify two events of translation silencing and describe spatiotemporal changes in subcellular localization of ribosomes during sporulation. We investigate the potential regulatory role of ribosomes during sporulation using a strain lacking zinc-independent paralogs of three zinc-dependent ribosomal proteins (L31, L33 and S14). The mutant strain exhibits delayed sporulation, reduced germination efficiency, dysregulated translation of metabolic and sporulation-related genes, and disruptions in translation silencing, particularly in late sporulation
Psychometric validation of the BDI-II among HIV-positive CHARTER study participants.
Rates of depression are high among individuals living with HIV. Accurate assessment of depressive symptoms among this population is important for ensuring proper diagnosis and treatment. The Beck Depression Inventory-II (BDI-II) is a widely used measure for assessing depression, however its psychometric properties have not yet been investigated for use with HIV-positive populations in the U.S. The current study was the first to assess the psychometric properties of the BDI-II among a large cohort of HIV-positive participants sampled at multiple sites across the U.S. as part of the CNS HIV Antiretroviral Therapy Effects Research (CHARTER) study. The BDI-II test scores showed good internal consistency (α = 0.93) and adequate test-retest reliability (ICC = 0.83) over a 6-month period. Using a ‘gold standard’ of major depressive disorder determined by the Composite International Diagnostic Interview (CIDI), sensitivity and specificity were maximized at a total cut-off score of 17 and a Receiver Operating Characteristic (ROC) analysis confirmed that the BDI-II is an adequate diagnostic measure for the sample (AUC = 0.83). The sensitivity and specificity of each score are provided graphically. Confirmatory factor analyses confirmed the best fit for a 3-factor model over 1-factor and 2-factor models and models with a higher-order factor included. The results suggest that the BDI-II is an adequate measure for assessing depressive symptoms among U.S. HIV-positive patients. Cut-off scores should be adjusted to enhance sensitivity or specificity as needed and the measure can be differentiated into cognitive, affective, and somatic depressive symptoms
Excited-state transition-rate measurements in C-18
Excited states in C-18 were populated by the one-proton knockout reaction of an intermediate energy radioactive N-19 beam. The lifetime of the first 2(+) state was measured with the Koln/NSCL plunger via the recoil distance method to be tau (2(1)(+)) = 22.4 +/- 0.9(stat)(-2.2)(+3.3)(syst) ps, which corresponds to a reduced quadrupole transition strength of B(E2; 2(1)(+) -> 0(1)(+)) = 3.64(-0.14)(+ 0.15)(stat)(-0.47)(+0.40)(syst) e(2)fm(4). In addition, an upper limit on the lifetime of a higher-lying state feeding the 2(1)(+) state was measured to be tau < 4.6 ps. The results are compared to large-scale ab initio no-core shell model calculations using two accurate nucleon-nucleon interactions and the importance-truncation scheme. The comparison provides strong evidence that the inclusion of three-body forces is needed to describe the low-lying excited-state properties of this A = 18 system
A cap 0-dependent mRNA capture method to analyze the yeast transcriptome
Analysis of the protein coding transcriptome by the
RNA sequencing requires either enrichment of the
desired fraction of coding transcripts or depletion
of the abundant non-coding fraction consisting
mainly of rRNA. We propose an alternative mRNA
enrichment strategy based on the RNA-binding
properties of the human IFIT1, an antiviral protein
recognizing cap 0 RNA. Here, we compare for
Saccharomyces cerevisiae an IFIT1-based mRNA
pull-down with yeast targeted rRNA depletion by
the RiboMinus method. IFIT1-based RNA capture
depletes rRNA more effectively, producing high
quality RNA-seq data with an excellent coverage of
the protein coding transcriptome, while depleting
cap-less transcripts such as mitochondrial or some
non-coding RNAs. We propose IFIT1 as a cost
effective and versatile tool to prepare mRNA libraries
for a variety of organisms with cap 0 mRNA
ends, including diverse plants, fungi and eukaryotic
microbes
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