The neurological underpinnings of cluttering: Some initial findings

Background Cluttering is a fluency disorder characterised by overly rapid or jerky speech patterns that compromise intelligibility. The neural correlates of cluttering are unknown but theoretical accounts implicate the basal ganglia and medial prefrontal cortex. Dysfunction in these brain areas would be consistent with difficulties in selection and control of speech motor programs that are characteristic of speech disfluencies in cluttering. There is a surprising lack of investigation into this disorder using modern imaging techniques. Here, we used functional MRI to investigate the neural correlates of cluttering. Method We scanned 17 adults who clutter and 17 normally fluent control speakers matched for age and sex. Brain activity was recorded using sparse-sampling functional MRI while participants viewed scenes and either (i) produced overt speech describing the scene or (ii) read out loud a sentence provided that described the scene. Speech was recorded and analysed off line. Differences in brain activity for each condition compared to a silent resting baseline and between conditions were analysed for each group separately (cluster-forming threshold Z > 3.1, extent p 30 voxels, uncorrected). Results In both conditions, the patterns of activation in adults who clutter and control speakers were strikingly similar, particularly at the cortical level. Direct group comparisons revealed greater activity in adults who clutter compared to control speakers in the lateral premotor cortex bilaterally and, as predicted, on the medial surface (pre-supplementary motor area). Subcortically, adults who clutter showed greater activity than control speakers in the basal ganglia. Specifically, the caudate nucleus and putamen were overactive in adults who clutter for the comparison of picture description with sentence reading. In addition, adults who clutter had reduced activity relative to control speakers in the lateral anterior cerebellum bilaterally. Eleven of the 17 adults who clutter also stuttered. This comorbid diagnosis of stuttering was found to contribute to the abnormal overactivity seen in the group of adults who clutter in the right ventral premotor cortex and right anterior cingulate cortex. In the remaining areas of abnormal activity seen in adults who clutter compared to controls, the subgroup who clutter and stutter did not differ from the subgroup who clutter but do not stutter. Conclusions Our findings were in good agreement with theoretical predictions regarding the neural correlates of cluttering. We found evidence for abnormal function in the basal ganglia and their cortical output target, the medial prefrontal cortex. The findings are discussed in relation to models of cluttering that point to problems with motor control of speech

Integrating musicology's heterogeneous data sources for better exploration

Musicologists have to consult an extraordinarily heterogeneous body of primary and secondary sources during all stages of their research. Many of these sources are now available online, but the historical dispersal of material across libraries and archives has now been replaced by segregation of data and metadata into a plethora of online repositories. This segregation hinders the intelligent manipulation of metadata, and means that extracting large tranches of basic factual information or running multi-part search queries is still enormously and needlessly time consuming. To counter this barrier to research, the “musicSpace” project is experimenting with integrating access to many of musicology’s leading data sources via a modern faceted browsing interface that utilises Semantic Web and Web2.0 technologies such as RDF and AJAX. This will make previously intractable search queries tractable, enable musicologists to use their time more efficiently, and aid the discovery of potentially significant information that users did not think to look for. This paper outlines our work to date

The importance of incorporating geology, soil, and landscape knowledge in freshwater farm planning in Aotearoa New Zealand

(c) The Author/sfals

Refraction of a Gaussian Seaway

Refraction of a Longuet-Higgins Gaussian sea by random ocean currents creates persistent local variations in average energy and wave action. These variations take the form of lumps or streaks, and they explicitly survive dispersion over wavelength and incoming wave propagation direction. Thus, the uniform sampling assumed in the venerable Longuet-Higgins theory does not apply following refraction by random currents. Proper handling of the non-uniform sampling results in greatly increased probability of freak wave formation. The present theory represents a synthesis of Longuet-Higgins Gaussian seas and the refraction model of White and Fornberg, which considered the effect of currents on a plane wave incident seaway. Using the linearized equations for deep ocean waves, we obtain quantitative predictions for the increased probability of freak wave formation when the refractive effects are taken into account. The crest height or wave height distribution depends primarily on the ``freak index", gamma, which measures the strength of refraction relative to the angular spread of the incoming sea. Dramatic effects are obtained in the tail of this distribution even for the modest values of the freak index that are expected to occur commonly in nature. Extensive comparisons are made between the analytical description and numerical simulations.Comment: 18 pages, 10 figure

The star-forming content of the W3 giant molecular cloud

We have surveyed a ~0.9-square-degree area of the W3 giant molecular cloud and star-forming region in the 850-micron continuum, using the SCUBA bolometer array on the James Clerk Maxwell Telescope. A complete sample of 316 dense clumps was detected with a mass range from around 13 to 2500 Msun. Part of the W3 GMC is subject to an interaction with the HII region and fast stellar winds generated by the nearby W4 OB association. We find that the fraction of total gas mass in dense, 850-micron traced structures is significantly altered by this interaction, being around 5% to 13% in the undisturbed cloud but ~25 - 37% in the feedback-affected region. The mass distribution in the detected clump sample depends somewhat on assumptions of dust temperature and is not a simple, single power law but contains significant structure at intermediate masses. This structure is likely to be due to crowding of sources near or below the spatial resolution of the observations. There is little evidence of any difference between the index of the high-mass end of the clump mass function in the compressed region and in the unaffected cloud. The consequences of these results are discussed in terms of current models of triggered star formation.Comment: 13 pages, 8 figures, 1 table (full source table available on request). Accepted for publication in Monthly Notices of the Royal Astronomical Society (Main Journal

The role of tank-treading motions in the transverse migration of a spheroidal vesicle in a shear flow

The behavior of a spheroidal vesicle, in a plane shear flow bounded from one side by a wall, is analysed when the distance from the wall is much larger than the spheroid radius. It is found that tank treading motions produce a transverse drift away from the wall, proportional to the spheroid eccentricity and the inverse square of the distance from the wall. This drift is independent of inertia, and is completely determined by the characteristics of the vesicle membrane. The relative strength of the contribution to drift from tank-treading motions and from the presence of inertial corrections, is discussed.Comment: 16 pages, 1 figure, Latex. To appear on J. Phys. A (Math. Gen.

Spatial distribution of beef cattle on a New Zealand hill country farm: monitoring the use of streams and wet areas

Grazing livestock are an important source of contamination of freshwater, particularly when they have direct access to streams. Cattle in particular contribute to riparian habitat deterioration through stream bank destruction and direct defecation and urination in streams. Exclusion of stock or planting of riparian areas, are the most common catchment management methods used to protect waterways. Given the relatively low returns from beef and sheep farming, both of these strategies are very expensive and often logistically prohibitive in steep hill county landscapes. Despite this, policy trends indicate that fencing of streams in agricultural catchments may become mandatory in the future. It is important that we understand how much time cattle spend in and around hill country streams and wet areas (wetlands and hill side seeps), in order to quantify the likely environmental benefits from such policies. The current study examined cattle movement data obtained using Global Positioning System (GPS) collars from experiments undertaken at Massey University’s hill country research farm, Tuapaka, near Palmerston North, to investigate the amount of time cattle spent in and around streams and wet areas. Animal movement data were collected over seven grazing events, in three winter periods (2012, 2013 and 2015). Permanent streams and wet areas were identified using a digital elevation model derived from 1m LiDAR data, aerial RGB images and RTK measurements. Cattle spent 3.3 – 6% (48 – 86 min/day) of their day in streams and wet areas consistently across the 7 data collections. Cattle spent more time in streams and wet areas during the afternoon. There are differences in the median amount of time individual animals spend in non-risk areas. Further research is necessary to evaluate how we can influence the amount of time cattle spend in riparian areas on hill country and how stream bank behaviour varies at different times of the year

Asymmetric correlation matrices: an analysis of financial data

We analyze the spectral properties of correlation matrices between distinct statistical systems. Such matrices are intrinsically non symmetric, and lend themselves to extend the spectral analyses usually performed on standard Pearson correlation matrices to the realm of complex eigenvalues. We employ some recent random matrix theory results on the average eigenvalue density of this type of matrices to distinguish between noise and non trivial correlation structures, and we focus on financial data as a case study. Namely, we employ daily prices of stocks belonging to the American and British stock exchanges, and look for the emergence of correlations between two such markets in the eigenvalue spectrum of their non symmetric correlation matrix. We find several non trivial results, also when considering time-lagged correlations over short lags, and we corroborate our findings by additionally studying the asymmetric correlation matrix of the principal components of our datasets.Comment: Revised version; 11 pages, 13 figure

Mesoscale eddy-internal wave coupling. Part I : symmetry, wave capture, and results from the Mid-Ocean Dynamics Experiment

Author Posting. © American Meteorological Society, 2008. This article is posted here by permission of American Meteorological Society for personal use, not for redistribution. The definitive version was published in Journal of Physical Oceanography 38 (2008): 2556-2574, doi:10.1175/2008JPO3666.1.Vertical profiles of horizontal velocity obtained during the Mid-Ocean Dynamics Experiment (MODE) provided the first published estimates of the high vertical wavenumber structure of horizontal velocity. The data were interpreted as being representative of the background internal wave field, and thus, despite some evidence of excess downward energy propagation associated with coherent near-inertial features that was interpreted in terms of atmospheric generation, these data provided the basis for a revision to the Garrett and Munk spectral model. These data are reinterpreted through the lens of 30 years of research. Rather than representing the background wave field, atmospheric generation, or even near-inertial wave trapping, the coherent high wavenumber features are characteristic of internal wave capture in a mesoscale strain field. Wave capture represents a generalization of critical layer events for flows lacking the spatial symmetry inherent in a parallel shear flow or isolated vortex.Salary support for this analysis was provided by Woods Hole Oceanographic Institution bridge support funds