6,148 research outputs found
Analyticity and the counting rule of matrix poles
By studying scattering amplitudes in the large limit, we
clarify the dependence of the matrix pole position. It is
demonstrated that analyticity and the counting rule exclude the existence
of matrix poles with . Especially the properties
of and with respect to the expansion are discussed.
We point out that in general tetra-quark resonances do not exist.Comment: This paper replaces hep-ph/0412175. The latter is withdraw
A hybrid systematic narrative review of instruments measuring home-based care nurses\u27 competency
Aim: The aim of the study was to identify and synthesize the contents and the psychometric properties of the existing instruments measuring home-based care (HBC) nurses\u27 competencies. Design: A hybrid systematic narrative review was performed. Review Methods: The eligible studies were reviewed to identify the competencies measured by the instruments for HBC nurses. The psychometric properties of instruments in development and psychometric testing design studies were also examined. The methodological quality of the studies was evaluated using the Medical Education Research Study Quality Instrument and COSMIN checklist accordingly. Data Sources: Relevant studies were searched on CINAHL, MEDLINE (via PubMed), EMBASE, PsychINFO and Scopus from 2000 to 2022. The search was limited to full-text items in the English language. Results: A total of 23 studies reporting 24 instruments were included. 12 instruments were adopted or modified by the studies while the other 12 were developed and psychometrically tested by the studies. None of the instruments encompassed all of the 10 home-based nursing care competencies identified in an earlier study. The two most frequently measured competencies were the management of health conditions, and critical thinking and problem-solving skills, while the two least measured competencies were quality and safety, and technological literacy. The content and structural validity of most instruments were inadequate since the adopted instruments were not initially designed or tested among HBC nurses. Conclusion: This review provides a consolidation of existing instruments that were used to assess HBC nurses\u27 competencies. The instruments were generally not comprehensive, and the content and structural validity were limited. Nonetheless, the domains, items and approaches to instrument development could be adopted to develop and test a comprehensive competency instrument for home-based nursing care practice in the future. Impact: This review consolidated instruments used to measure home-based care nurses\u27 competency. The instruments were often designed for ward-based care nurses hence a comprehensive and validated home-based nursing care competency instrument is needed. Nurses, researchers and nursing leaders could consider the competency instruments identified in this review to measure nurses\u27 competencies, while a home-based nursing care competency scale is being developed. Patient or Public Contribution: No patient or public contribution was required in this review
BaFe2As2 Surface Domains and Domain Walls: Mirroring the Bulk Spin Structure
High-resolution scanning tunneling microscopy (STM) measurements on
BaFe2As2-one of the parent compounds of the iron-based superconductors-reveals
a (1x1) As-terminated unit cell on the (001) surface. However, there are
significant differences of the surface unit cell compared to the bulk: only one
of the two As atoms in the unit cell is imaged and domain walls between
different (1x1) regions display a C2 symmetry at the surface. It should have
been C2v if the STM image reflected the geometric structure of the surface or
the orthorhombic bulk. The inequivalent As atoms and the bias dependence of the
domain walls indicate that the origin of the STM image is primarily electronic
not geometric. We argue that the surface electronic topography mirrors the bulk
spin structure of BaFe2As2, via strong orbital-spin coupling
Graphene Transport at High Carrier Densities using a Polymer Electrolyte Gate
We report the study of graphene devices in Hall-bar geometry, gated with a
polymer electrolyte. High densities of 6 are
consistently reached, significantly higher than with conventional back-gating.
The mobility follows an inverse dependence on density, which can be correlated
to a dominant scattering from weak scatterers. Furthermore, our measurements
show a Bloch-Gr\"uneisen regime until 100 K (at 6.2 ),
consistent with an increase of the density. Ubiquitous in our experiments is a
small upturn in resistivity around 3 , whose origin is
discussed. We identify two potential causes for the upturn: the renormalization
of Fermi velocity and an electrochemically-enhanced scattering rate.Comment: 13 pages, 4 figures, Published Versio
Onset of dielectric modes at 110K and 60K due to local lattice distortions in non-superconducting YBa_{2}Cu_{3}O_{6.0} crystals
We report the observation of two dielectric transitions at 110K and 60K in
the microwave response of non-superconducting YBa_{2}Cu_{3}O_{6.0} crystals.
The transitions are characterized by a change in polarizability and presence of
loss peaks, associated with overdamped dielectric modes. An explanation is
presented in terms of changes in polarizability of the apical O atoms in the
Ba-O layer, affected by lattice softening at 110K, due to change in buckling of
the Cu-O layer. The onset of another mode at 60K strongly suggests an
additional local lattice change at this temperature. Thus microwave dielectric
measurements are sensitive indicators of lattice softening which may be
relevant to superconductivity.Comment: 5 pages, 3 ps format figure
Double di ffential fragmentation cross sections measurements of 95 MeV/u 12C on thin targets for hadrontherapy
During therapeutic treatment with heavy ions like carbon, the beam undergoes
nuclear fragmentation and secondary light charged particles, in particular
protons and alpha particles, are produced. To estimate the dose deposited into
the tumors and the surrounding healthy tissues, an accurate prediction on the
fluences of these secondary fragments is necessary. Nowadays, a very limited
set of double di ffential carbon fragmentation cross sections are being
measured in the energy range used in hadrontherapy (40 to 400 MeV/u).
Therefore, new measurements are performed to determine the double di ffential
cross section of carbon on di erent thin targets. This work describes the
experimental results of an experiment performed on May 2011 at GANIL. The
double di ffential cross sections and the angular distributions of secondary
fragments produced in the 12C fragmentation at 95 MeV/u on thin targets (C,
CH2, Al, Al2O3, Ti and PMMA) have been measured. The experimental setup will be
precisely described, the systematic error study will be explained and all the
experimental data will be presented.Comment: Submitted to PR
Divergent LIN28-mRNA associations result in translational suppression upon the initiation of differentiation
LIN28 function is fundamental to the activity and behavior of human embryonic stem cells (hESCs) and induced pluripotent stem cells. Its main roles in these cell types are the regulation of translational efficiency and let-7 miRNA maturation. However, LIN28-associated mRNA cargo shifting and resultant regulation of translational efficiency upon the initiation of differentiation remain unknown. An RNA-immunoprecipitation and microarray analysis protocol, eRIP, that has high specificity and sensitivity was developed to test endogenous LIN28-associated mRNA cargo shifting. A combined eRIP and polysome analysis of early stage differentiation of hESCs with two distinct differentiation cues revealed close similarities between the dynamics of LIN28 association and translational modulation of genes involved in the Wnt signaling, cell cycle, RNA metabolism and proteasomal pathways. Our data demonstrate that change in translational efficiency is a major contributor to early stages of differentiation of hESCs, in which LIN28 plays a central role. This implies that eRIP analysis of LIN28-associated RNA cargoes may be used for rapid functional quality control of pluripotent stem cells under manufacture for therapeutic applications
The Puf family of RNA-binding proteins in plants: phylogeny, structural modeling, activity and subcellular localization
<p>Abstract</p> <p>Background</p> <p>Puf proteins have important roles in controlling gene expression at the post-transcriptional level by promoting RNA decay and repressing translation. The Pumilio homology domain (PUM-HD) is a conserved region within Puf proteins that binds to RNA with sequence specificity. Although Puf proteins have been well characterized in animal and fungal systems, little is known about the structural and functional characteristics of Puf-like proteins in plants.</p> <p>Results</p> <p>The Arabidopsis and rice genomes code for 26 and 19 Puf-like proteins, respectively, each possessing eight or fewer Puf repeats in their PUM-HD. Key amino acids in the PUM-HD of several of these proteins are conserved with those of animal and fungal homologs, whereas other plant Puf proteins demonstrate extensive variability in these amino acids. Three-dimensional modeling revealed that the predicted structure of this domain in plant Puf proteins provides a suitable surface for binding RNA. Electrophoretic gel mobility shift experiments showed that the Arabidopsis AtPum2 PUM-HD binds with high affinity to BoxB of the Drosophila Nanos Response Element I (NRE1) RNA, whereas a point mutation in the core of the NRE1 resulted in a significant reduction in binding affinity. Transient expression of several of the Arabidopsis Puf proteins as fluorescent protein fusions revealed a dynamic, punctate cytoplasmic pattern of localization for most of these proteins. The presence of predicted nuclear export signals and accumulation of AtPuf proteins in the nucleus after treatment of cells with leptomycin B demonstrated that shuttling of these proteins between the cytosol and nucleus is common among these proteins. In addition to the cytoplasmically enriched AtPum proteins, two AtPum proteins showed nuclear targeting with enrichment in the nucleolus.</p> <p>Conclusions</p> <p>The Puf family of RNA-binding proteins in plants consists of a greater number of members than any other model species studied to date. This, along with the amino acid variability observed within their PUM-HDs, suggests that these proteins may be involved in a wide range of post-transcriptional regulatory events that are important in providing plants with the ability to respond rapidly to changes in environmental conditions and throughout development.</p
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