Apraxia in progressive nonfluent aphasia

The clinical and neuroanatomical correlates of specific apraxias in neurodegenerative disease are not well understood. Here we addressed this issue in progressive nonfluent aphasia (PNFA), a canonical subtype of frontotemporal lobar degeneration that has been consistently associated with apraxia of speech (AOS) and in some cases orofacial apraxia, limb apraxia and/or parkinsonism. Sixteen patients with PNFA according to current consensus criteria were studied. Three patients had a corticobasal syndrome (CBS) and two a progressive supranuclear palsy (PSP) syndrome. Speech, orofacial and limb praxis functions were assessed using the Apraxia Battery for Adults-2 and a voxel-based morphometry (VBM) analysis was conducted on brain MRI scans from the patient cohort in order to identify neuroanatomical correlates. All patients had AOS based on reduced diadochokinetic rate, 69% of cases had an abnormal orofacial apraxia score and 44% of cases (including the three CBS cases and one case with PSP) had an abnormal limb apraxia score. Severity of orofacial apraxia (but not AOS or limb apraxia) correlated with estimated clinical disease duration. The VBM analysis identified distinct neuroanatomical bases for each form of apraxia: the severity of AOS correlated with left posterior inferior frontal lobe atrophy; orofacial apraxia with left middle frontal, premotor and supplementary motor cortical atrophy; and limb apraxia with left inferior parietal lobe atrophy. Our findings show that apraxia of various kinds can be a clinical issue in PNFA and demonstrate that specific apraxias are clinically and anatomically dissociable within this population of patients

Ten simple rules for reporting voxel-based morphometry studies

Voxel-based morphometry [Ashburner, J. and Friston, K.J., 2000. Voxel-based morphometry—the methods. NeuroImage 11(6 Pt 1), 805–821] is a commonly used tool for studying patterns of brain change in development or disease and neuroanatomical correlates of subject characteristics. In performing a VBM study, many methodological options are available; if the study is to be easily interpretable and repeatable, the processing steps and decisions must be clearly described. Similarly, unusual methods and parameter choices should be justified in order to aid readers in judging the importance of such options or in comparing the work with other studies. This editorial suggests core principles that should be followed and information that should be included when reporting a VBM study in order to make it transparent, replicable and useful

Precise Determination of the Neutron Magnetic Form Factor to Higher Q2Q^2

The neutron elastic magnetic form factor $G_M^n$ has been extracted from quasielastic scattering from deuterium in the CEBAF Large Acceptance Spectrometer, CLAS. The kinematic coverage of the measurement is continuous over a broad range, extending from below 1 $GeV^2$ to nearly 5 $GeV^2$ in four-momentum transfer squared. High precision is achieved by employing a ratio technique in which most uncertainties cancel, and by a simultaneous in-situ calibration of the neutron detection efficiency, the largest correction to the data. Preliminary results are shown with statistical errors only.Comment: Contribution to the proceedings of the Tenth International Conference on Baryons (2004), to be published in Nuclear Physics, Section

Perineal and posterior vaginal wall reconstruction with superior and inferior gluteal artery perforator flaps

Perineal and posterior vaginal wall reconstruction following abdominoperineal and local cancer resection entails replacement of volume between the perineum and sacrum and restoration of a functional vagina. Ideal local reconstructive options include those which avoid functional muscle sacrifice, do not interfere with colostomy formation, and avoid the use of irradiated tissue. In avoiding the donor site morbidity of other options, we describe a fasciocutaneous option for the reconstruction of the perineum and posterior vaginal wall. We present our technique of superior and inferior gluteal artery perforator (SGAP or IGAP) flaps to reconstruct such defects. Fourteen patients between 2004 and 2008 underwent 11 SGAP and three IGAP flaps. There were no flap failures or partial flap losses and no postoperative hernias. All female patients reported resumption of sexual intercourse following this procedure. Our experience in both the immediate and delayed setting is that this technique produces a good functional outcome with low donor-site morbidity

Synthesis and structural characterization of Zn2+, Cd2+ and Hg2+ complexes with tripyrrolidinophosphine chalcogenides

Authors are grateful to the Tunisian Ministry of High Education and Scientific Research for support [grant number: LR99ES14] and to the French Service for Cooperation and Cultural Action (SCAC) in Nouakchott, Mauritania for a scholarship to KE.Six new complexes of zinc(II), cadmium(II) and mercury(II) chlorides with tripyrrolidinophosphine chalcogenides of the types [MCl2(Pyrr3PE)2] (M = Zn, E = S (1) or E = Se (2); M = Cd, E = S (3) or E = Se (4)) and [{HgCl(Pyrr3PE)}2(µ-Cl)2] (E = S (5) or Se (6)) have been prepared in yields of 66-92% by reaction of the ligands with metal chloride in ethanol and characterized by 1H and 31P NMR, IR, elemental analysis, conductivity, and single crystal X-ray diffraction analysis. The results show that the complexes are pseudo-tetrahedral containing coordinated chloride ions. Interestingly, the X-ray studies reveal that while the title ligands produce dinuclear complexes with Hg, their Cd and Zn complexes are mononuclear. The tetrahedral bond angles vary from 85.69(5)° to 126.25(4)° in dinuclear complexes 5 and 6 and from 93.51(3)° to 117.38(3)° in mononuclear species 2-4. The E = S bond lengths are in the range 1.999(9)-2.198(2) Å. The coordination properties of the title ligands are discussed and compared to those obtained for their bulkier counterparts.PostprintPeer reviewe

Marine ecosystem indicators are sensitive to ecosystem boundaries and spatial scale

Time series indicators are widely used in ecosystem-based management. A suite of indicators is typically calculated for a static region or multiple subregions and presented in an ecosystem assessment (EA). These are used to guide management decisions or determine environmental status. Yet, few studies have examined how the spatial scale of an EA influences indicator behavior. We explore this question using the Northwest Atlantic continental shelf ecosystem (USA). We systematically divided the ecosystem at six spatial scales (31 unique units), covering spatial extents from 250,000 km2 to 20,000 km2. The same 22 indicators were calculated for each unit, assessed for trends, and evaluated as 31 independent EAs. We found that the detected signals of indicator trends depended on the spatial scale at which the ecosystem was defined. A single EA for the whole region differed by 23% (in terms of the 22 indicator trend tests) relative to ones for spatially nested 120,000 km2 subunits, and by up to 36% for EAs at smaller scales. Indicator trend disagreement occurred because (most common) a localized trend was perceived as widespread, (common) a local trend was obscured by aggregating data over a large region, or (least common) a local trend switched direction when examined at a broader scale. Yet, there was variation among indicators in their scale sensitivity related to trophic level. Indicators of temperature, chlorophyll-a, and zooplankton were spatially coherent: trends portrayed were similar regardless of scale. Mid-trophic level indicators (fish and invertebrates) showed more spatial variation in trends. We also compared trend magnitude and indicator values to spatial extent and found relationships consistent with scaling theory. Indicators at broad scales produced subdued trends and values relative to indicators developed at smaller spatial scales, which often portrayed ‘hotspots’ of local abundance or strong trend. Our results imply that subsequent uses of indicators (e.g., determining environmental status, risk assessments, management decisions) are also sensitive to ecosystem delineation and scale. We suggest that indicators and EAs should be done at multiple spatial scales and complimented with spatially explicit analysis to reflect the hierarchical structure of ecosystems. One scale is not best, but rather we gain a new level of understanding at each scale examined that can contribute to management decisions in a multiscale governance framework characterized by goals and objectives with relevance at different scales

Effective dimensions and percolation in hierarchically structured scale-free networks

We introduce appropriate definitions of dimensions in order to characterize the fractal properties of complex networks. We compute these dimensions in a hierarchically structured network of particular interest. In spite of the nontrivial character of this network that displays scale-free connectivity among other features, it turns out to be approximately one-dimensional. The dimensional characterization is in agreement with the results on statistics of site percolation and other dynamical processes implemented on such a network.Comment: 5 pages, 5 figure