2,608 research outputs found
Five Dimensions of School-Based Counseling Practice: Factor Analysis Identification Using the International Survey of School Counselors’ Activities
This article describes a factor analytic study designed to identify the underlying dimensions of school-based counseling practice that will be useful in describing cross-national differences in school-based counseling practice and in enabling comparative research on school-based counseling policy and effectiveness. Practicing school-based counselors (N = 2913) from 10 countries (China, Costa Rica, India, Kenya, South Korea, Malta, Nigeria, Turkey, the United States, and Venezuela) used the International Survey of School-Based Counseling Activities (ISSCA) to rate the centrality of 40 activities to the role of a school-based counselor. Factor analysis determined that five dimensions adequately described the school-based counselor role: Counseling Services; Advocacy and Systemic Improvement; Prevention Programs; Administrator Role; and Educational and Career Planning. Analysis of Bartlett Factor Score averages revealed that each country demonstrates a unique profile which reflects that country’s dominant mode of practice. This lead article describes these dimensions and the cross-national differences on these dimensions. Subsequent articles in this special issue describe country-specific results and explain factors that affect practice within each country
Semiparametric Multivariate Accelerated Failure Time Model with Generalized Estimating Equations
The semiparametric accelerated failure time model is not as widely used as
the Cox relative risk model mainly due to computational difficulties. Recent
developments in least squares estimation and induced smoothing estimating
equations provide promising tools to make the accelerate failure time models
more attractive in practice. For semiparametric multivariate accelerated
failure time models, we propose a generalized estimating equation approach to
account for the multivariate dependence through working correlation structures.
The marginal error distributions can be either identical as in sequential event
settings or different as in parallel event settings. Some regression
coefficients can be shared across margins as needed. The initial estimator is a
rank-based estimator with Gehan's weight, but obtained from an induced
smoothing approach with computation ease. The resulting estimator is consistent
and asymptotically normal, with a variance estimated through a multiplier
resampling method. In a simulation study, our estimator was up to three times
as efficient as the initial estimator, especially with stronger multivariate
dependence and heavier censoring percentage. Two real examples demonstrate the
utility of the proposed method
Isostructural Phase Transition of TiN Under High Pressure
In situ high-pressure energy dispersive x-ray diffraction experiments on
polycrystalline powder TiN with NaCl-type structure have been conducted with
the pressure up to 30.1 GPa by using the diamond anvil cell instrument with
synchrotron radiation at room tempearture. The experimental results suggested
that an isostructural phase transition might exist at about 7 GPa as revealed
by the discontinuity of V/V0 with pressure.Comment: submitte
Improved bending property of half-filled photonic crystal fiber
Author name used in this publication: Yeuk Lai Hoo2009-2010 > Academic research: refereed > Publication in refereed journalVersion of RecordPublishe
Phenotypic and functional abnormalities of bone marrow-derived dendritic cells in systemic lupus erythematosus
Introduction: Systemic lupus erythematosus (SLE) is an autoimmune disease characterized by autoreactive T and B cells, which are believed to be secondary to deficient dendritic cells (DCs). However, whether DC abnormalities occur during their development in the bone marrow (BM) or in the periphery is not known.Methods: Thirteen patients with SLE and 16 normal controls were recruited. We studied the morphology, phenotype, and functional abilities of bone marrow-derived dendritic cells (BMDCs) generated by using two culture methods: FMS-like tyrosine kinase 3 (Flt3)-ligand (FL) and granulocyte-macrophage colony-stimulating factor (GM-CSF) plus interleukin-4 (IL-4), respectively.Results: BMDCs induced by FL exhibited both myeloid (mDC) and plasmacytoid DC (pDC) features, whereas GM-CSF/IL-4 induced mDC generation. Substantial phenotypic and functional defects of BMDCs were found from patients with SLE at different stages of cell maturation. When compared with healthy controls, SLE immature BM FLDCs expressed higher levels of CCR7. Both immature and mature SLE BM FLDCs expressed higher levels of CD40 and CD86 and induced stronger T-cell proliferation. SLE BM mDCs expressed higher levels of CD40 and CD86 but lower levels of HLA-DR and a lower ability to stimulate T-cell proliferation when compared with control BM mDCs.Conclusions: Our data are in accordance with previous reports that suggest that DCs have a potential pathogenic role in SLE. Defects of these cells are evident during their development in BM. BM mDCs are deficient, whereas BM pDCs, which are part of BM FLDCs, are the likely culprit in inducing autoimmunity in SLE. © 2010 Nie et al.; licensee BioMed Central Ltd.published_or_final_versio
Parallel symbolic state-space exploration is difficult, but what is the alternative?
State-space exploration is an essential step in many modeling and analysis
problems. Its goal is to find the states reachable from the initial state of a
discrete-state model described. The state space can used to answer important
questions, e.g., "Is there a dead state?" and "Can N become negative?", or as a
starting point for sophisticated investigations expressed in temporal logic.
Unfortunately, the state space is often so large that ordinary explicit data
structures and sequential algorithms cannot cope, prompting the exploration of
(1) parallel approaches using multiple processors, from simple workstation
networks to shared-memory supercomputers, to satisfy large memory and runtime
requirements and (2) symbolic approaches using decision diagrams to encode the
large structured sets and relations manipulated during state-space generation.
Both approaches have merits and limitations. Parallel explicit state-space
generation is challenging, but almost linear speedup can be achieved; however,
the analysis is ultimately limited by the memory and processors available.
Symbolic methods are a heuristic that can efficiently encode many, but not all,
functions over a structured and exponentially large domain; here the pitfalls
are subtler: their performance varies widely depending on the class of decision
diagram chosen, the state variable order, and obscure algorithmic parameters.
As symbolic approaches are often much more efficient than explicit ones for
many practical models, we argue for the need to parallelize symbolic
state-space generation algorithms, so that we can realize the advantage of both
approaches. This is a challenging endeavor, as the most efficient symbolic
algorithm, Saturation, is inherently sequential. We conclude by discussing
challenges, efforts, and promising directions toward this goal
Identification and characterization of seven new exon 11-associated splice variants of the rat mu opioid receptor gene, OPRM1
<p>Abstract</p> <p>Background</p> <p>The mouse mu opioid receptor (OPRM1) gene undergoes extensive alternative splicing at both the 3'- and 5'-ends of the gene. Previously, several C-terminal variants generated through 3' splicing have been identified in the rat OPRM1 gene. In both mice and humans 5' splicing generates a number of exon 11-containing variants. Studies in an exon 11 knockout mouse suggest the functional importance of these exon 11-associated variants in mediating the analgesic actions of a subset of mu opioids, including morphine-6β-glucuronide (M6G) and heroin, but not others such as morphine and methadone. We now have examined 5' splicing in the rat.</p> <p>Results</p> <p>The current studies identified in the rat a homologous exon 11 and seven exon 11-associated variants, suggesting conservation of exon 11 and its associated variants among mouse, rat and human. RT-PCR revealed marked differences in the expression of these variants across several brain regions, implying region-specific mRNA processing of the exon 11-associated variants. Of the seven rat exon 11-associated variants, four encoded the identical protein as found in rMOR-1, two predicted 6 TM variants, and one, rMOR-1H2, generated a novel N-terminal variant in which a stretch of an additional 50 amino acids was present at the N-terminus of the previously established rMOR-1 sequence. When expressed in CHO cells, the presence of the additional 50 amino acids in rMOR-1H2 significantly altered agonist-induced G protein activation with little effect on opioid binding.</p> <p>Conclusion</p> <p>The identification of the rat exon 11 and its associated variants further demonstrated conservation of 5' splicing in OPRM1 genes among rodents and humans. The functional relevance of these exon 11 associated variants was suggested by the region-specific expression of their mRNAs and the influence of the N-terminal sequence on agonist-induced G protein coupling in the novel N-terminal variant, rMOR-1H2. The importance of the exon 11-associated variants in mice in M6G and heroin analgesia revealed in the exon 11 knockout mouse implies that these analogous rat variants may also play similar roles in rat. The complexity created by alternative splicing of the rat OPRM1 gene may provide important insights of understanding the diverse responses to the various mu opioids seen in rats.</p
Spectra of Baryons Containing Two Heavy Quarks in Potential Model
In this work, we employ the effective vertices for interaction between
diquarks (scalar or axial-vector) and gluon where the form factors are derived
in terms of the B-S equation, to obtain the potential for baryons including a
light quark and a heavy diquark. The concerned phenomenological parameters are
obtained by fitting data of mesons instead of the heavy quarkonia.
The operator ordering problem in quantum mechanics is discussed. Our numerical
results indicate that the mass splitting between and
is very small and it is consistent with the heavy quark effective
theory (HQET).Comment: 16 page
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