The role of stimulus salience and attentional capture across the neural hierarchy in a stop-signal task.

Inhibitory motor control is a core function of cognitive control. Evidence from diverse experimental approaches has linked this function to a mostly right-lateralized network of cortical and subcortical areas, wherein a signal from the frontal cortex to the basal ganglia is believed to trigger motor-response cancellation. Recently, however, it has been recognized that in the context of typical motor-control paradigms those processes related to actual response inhibition and those related to the attentional processing of the relevant stimuli are highly interrelated and thus difficult to distinguish. Here, we used fMRI and a modified Stop-signal task to specifically examine the role of perceptual and attentional processes triggered by the different stimuli in such tasks, thus seeking to further distinguish other cognitive processes that may precede or otherwise accompany the implementation of response inhibition. In order to establish which brain areas respond to sensory stimulation differences by rare Stop-stimuli, as well as to the associated attentional capture that these may trigger irrespective of their task-relevance, we compared brain activity evoked by Stop-trials to that evoked by Go-trials in task blocks where Stop-stimuli were to be ignored. In addition, region-of-interest analyses comparing the responses to these task-irrelevant Stop-trials, with those to typical relevant Stop-trials, identified separable activity profiles as a function of the task-relevance of the Stop-signal. While occipital areas were mostly blind to the task-relevance of Stop-stimuli, activity in temporo-parietal areas dissociated between task-irrelevant and task-relevant ones. Activity profiles in frontal areas, in turn, were activated mainly by task-relevant Stop-trials, presumably reflecting a combination of triggered top-down attentional influences and inhibitory motor-control processes.

Ventricular conduction and long-term heart failure outcomes and mortality in African Americans: insights from the Jackson Heart Study.

BACKGROUND: QRS prolongation is associated with adverse outcomes in mostly white populations, but its clinical significance is not well established for other groups. We investigated the association between QRS duration and mortality in African Americans. METHODS AND RESULTS: We analyzed data from 5146 African Americans in the Jackson Heart Study stratified by QRS duration on baseline 12-lead ECG. We defined QRS prolongation as QRS≥100 ms. We assessed the association between QRS duration and all-cause mortality using Cox proportional hazards models and reported the cumulative incidence of heart failure hospitalization. We identified factors associated with the development of QRS prolongation in patients with normal baseline QRS. At baseline, 30% (n=1528) of participants had QRS prolongation. The cumulative incidences of mortality and heart failure hospitalization were greater with versus without baseline QRS prolongation: 12.6% (95% confidence interval [CI], 11.0-14.4) versus 7.1% (95% CI, 6.3-8.0) and 8.2% (95% CI, 6.9-9.7) versus 4.4% (95% CI, 3.7-5.1), respectively. After risk adjustment, QRS prolongation was associated with increased mortality (hazard ratio, 1.27; 95% CI, 1.03-1.56; P=0.02). There was a linear relationship between QRS duration and mortality (hazard ratio per 10 ms increase, 1.06; 95% CI, 1.01-1.12). Older age, male sex, prior myocardial infarction, lower ejection fraction, left ventricular hypertrophy, and left ventricular dilatation were associated with the development of QRS prolongation. CONCLUSIONS: QRS prolongation in African Americans was associated with increased mortality and heart failure hospitalization. Factors associated with developing QRS prolongation included age, male sex, prior myocardial infarction, and left ventricular structural abnormalities.

African-American Composers for the Concert Saxophone: A Look at Three Prolific Composers

African-American composers within the field of classical music have made very profound contributions to the literature. In the field of chamber music, Scott Joplin, William Grant Still, Adolphus Hailstork and other composers illustrious composers have created an established and well-documented body of repertoire for many orchestral wind instruments. The saxophone repertoire, however, has not been developed as fully due to its limited tradition as an orchestral instrument and its prominence in the tradition of jazz and popular music. African-American composers in particular appear to be significantly under-represented within the standard concert saxophone literature. My personal experiences with saxophone repertoire in academic settings, solo recitals, conferences and in surveys of standard repertoire from nationally-recognized saxophone teachers support this assertion. There are many African-American composers who have made substantial contributions to the body of repertoire for the concert saxophone. This dissertation examines the works of three prolific African-American composers for the concert saxophone; Dr. Yusef A. Lateef, Andrew N. White III, and Dr. David N. Baker. All have composed more than five separate works featuring the concert saxophone. This project comprises three recitals, each dedicated to one of the three composers selected for this dissertation. Each recital presented will present their compositions featuring the saxophone as a soloist with various types of accompaniment. The project also includes newly-created piano reductions of Dr. David Baker's works for saxophone and orchestra made collaboratively with Baker and arranger John Leszczynski.

A new inversion procedure for confocal scanning microscopy and other bandlimited signal processing problems

We find a simple analytic expression for the inverse of an infinite matrix related to the problem of data reduction in confocal scanning microscopy and other band-limited signal processing problems. Potential applications of this result to practical problems are outlined. The matrix arises from a sampling expansion approach to the integral equation.

Signal restoration from band-pass filtered data

The restoration problem for a band-pass linear system is examined in the case the input signal is weighted by a profile function. The singular system is evaluated analytically for three different forms of the profile function. An example of restoration process is presented.

Canary grass : variations in grain yield and other agronomically important features in response to different plant densities

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Canary grass : variations in grain yield and other agronomically important features in response to different plant densities

p.43-55

Incorporación tecnológica en explotaciones ganaderas de tipo familiar de la cuenca del Salado : control de paja colorada (Paspalum quadrifarium) y rejuvenecimiento de rye-grass en pastizales naturales

p.107-120

First report of the occurence of East African cassava mosaic virus-Uganda (EACMV-UG) in Angola

No abstract is available for this article.

Solid phase velocity measurements utilising electrostatic sensors and cross correlation signal processing

Gas-solids two phase systems are widely employed within process plant in the form of pneumatic conveyors, dust extraction systems and solid fuel injection systems. The measurement of solids phase velocity therefore has wide potential application in flow monitoring and, in conjunction with density measurement instrumentation, solids mass flow rate measurement. Historically, a number of authors have detailed possible measurement techniques, and some have published limited test results. It is, however, apparent that none of these technologies have found wide application in industry. Solids phase velocity measurements were undertaken using real time cross correlation of signals from two electrostatic sensors spaced axially along a pipeline conveying pulverised coal (PF). Details of the measurement equipment, the pilot scale test rig and the test results are presented.

Safety issues with the South African Pebble Bed Modular Reactor: when were the issues apparent? A briefing paper

This is a briefing report on when the safety issues identified in a July 2008 report by Jülich should have become apparent In July 2008, the German Jülich nuclear research centre published a report entitled ‘A safety re-evaluation of the AVR pebble bed reactor operation and its consequences for future HTR concepts.’ It concluded: ‘pebble bed HTRs require additional safety related R&D effort and updating of safety analyses before construction.’