2,412 research outputs found
Temporal discrimination: Mechanisms and relevance to adult-onset dystonia
Temporal discrimination is the ability to determine that two sequential sensory stimuli are separated in time. For any individual, the temporal discrimination threshold (TDT) is the minimum interval at which paired sequential stimuli are perceived as being asynchronous; this can be assessed, with high test-retest and inter-rater reliability, using a simple psychophysical test. Temporal discrimination is disordered in a number of basal ganglia diseases including adult-onset dystonia, of which the two most common phenotypes are cervical dystonia and blepharospasm. The causes of adult-onset focal dystonia are unknown; genetic, epigenetic, and environmental factors are relevant. Abnormal TDTs in adult-onset dystonia are associated with structural and neurophysiological changes considered to reflect defective inhibitory interneuronal processing within a network which includes the superior colliculus, basal ganglia, and primary somatosensory cortex. It is hypothesized that abnormal temporal discrimination is a mediational endophenotype and, when present in unaffected relatives of patients with adult-onset dystonia, indicates non-manifesting gene carriage. Using the mediational endophenotype concept, etiological factors in adult-onset dystonia may be examined including (i) the role of environmental exposures in disease penetrance and expression; (ii) sexual dimorphism in sex ratios at age of onset; (iii) the pathogenesis of non-motor symptoms of adult-onset dystonia; and (iv) subcortical mechanisms in disease pathogenesis
Search Practices for Discontinuous Innovation: Scale Development and Construct Validation
Managing innovation and particularly searching for new ideas in a steady state environment is really different than in discontinuous conditions where traditional practices and routines may prove ineffective. This paper reviews and empirically explores the field of search strategies and practices for discontinuous innovation and, for the first time, tests the validity of a "Discontinuous Innovation (DI) Search Capacity" construct. Based on a comprehensive literature review on the innovation search stage and on the evidence of more than 80 case studies reported by the Discontinuous Innovation Lab a questionnaire was developed and submitted to a 500 high tech firm sample. Four DI Search dimensions were identified, each consisting of a bundle of interrelated yet distinct practices. We empirically tested the DI Search Capacity and measured it as second-order construct by using the Structural Equation Modelling
F-theory on Quotient Threefolds with (2,0) Discrete Superconformal Matter
We explore 6-dimensional compactifications of F-theory exhibiting (2,0)
superconformal theories coupled to gravity that include discretely charged
superconformal matter. Beginning with F-theory geometries with Abelian gauge
fields and superconformal sectors, we provide examples of Higgsing transitions
which break the gauge symmetry to a discrete remnant in which the matter
fields are also non-trivially coupled to a (2,0) SCFT. In the compactification
background this corresponds to a geometric transition linking two fibered
Calabi-Yau geometries defined over a singular base complex surface. An
elliptically fibered Calabi-Yau threefold with non-zero Mordell-Weil rank can
be connected to a smooth non-simply connected genus one fibered geometry
constructed as a Calabi-Yau quotient. These hyperconifold transitions exhibit
multiple fibers in co-dimension 2 over the base.Comment: 60 pages, 11 pages appendices, 18 Figures, 2 Tables, references
added, typos corrected, extended introduction, extended discussion of Section
4.3, published versio
Weak-lensing calibration of a stellar mass-based mass proxy for redMaPPer and Voronoi Tessellation clusters in SDSS Stripe 82
We present the first weak lensing calibration of , a new galaxy
cluster mass proxy corresponding to the total stellar mass of red and blue
members, in two cluster samples selected from the SDSS Stripe 82 data: 230
redMaPPer clusters at redshift and 136 Voronoi Tessellation
(VT) clusters at . We use the CS82 shear catalog and stack
the clusters in bins to measure a mass-observable power law
relation. For redMaPPer clusters we obtain , . For VT clusters, we find
, and , for a low and a high redshift bin, respectively. Our results are
consistent, internally and with the literature, indicating that our method can
be applied to any cluster finding algorithm. In particular, we recommend that
be used as the mass proxy for VT clusters. Catalogs including
measurements will enable its use in studies of galaxy evolution
in clusters and cluster cosmology.Comment: Updated to be consistent with the published versio
MicroRNA-155 influences B-cell function through PU.1 in rheumatoid arthritis
MicroRNA-155 (miR-155) is an important regulator of B cells in mice. B cells have a critical role in the pathogenesis of rheumatoid arthritis (RA). Here we show that miR-155 is highly expressed in peripheral blood B cells from RA patients compared with healthy individuals, particularly in the IgD-CD27- memory B-cell population in ACPA+ RA. MiR-155 is highly expressed in RA B cells from patients with synovial tissue containing ectopic germinal centres compared with diffuse synovial tissue. MiR-155 expression is associated reciprocally with lower expression of PU.1 at B-cell level in the synovial compartment. Stimulation of healthy donor B cells with CD40L, anti-IgM, IL-21, CpG, IFN-α, IL-6 or BAFF induces miR-155 and decreases PU.1 expression. Finally, inhibition of endogenous miR-155 in B cells of RA patients restores PU.1 and reduces production of antibodies. Our data suggest that miR-155 is an important regulator of B-cell activation in RA
Seroprevalence of Ebola virus infection in Bombali District, Sierra Leone
A serosurvey of anti-Ebola Zaire virus nucleoprotein IgG prevalence was carried out among Ebola virus disease survivors and their Community Contacts in Bombali District, Sierra Leone. Our data suggest that the specie of Ebola virus (Zaire) responsible of the 2013-2016 epidemic in West Africa may cause mild or asymptomatic infection in a proportion of cases, possibly due to an efficient immune response
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