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Distinct Elements (distinct + element)

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Medical Sciences42%

Terms modified by Distinct Elements

  • distinct element method
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    Selected Abstracts

    Altered Impulse Control in Alcohol Dependence: Neural Measures of Stop Signal Performance

    ALCOHOLISM, Issue 4 2009
    Chiang-shan Ray Li
    Background:, Altered impulse control has been implicated in the shaping of habitual alcohol use and eventual alcohol dependence. We sought to identify the neural correlates of altered impulse control in 24 abstinent patients with alcohol dependence (PAD), as compared to 24 demographics matched healthy control subjects (HC). In particular, we examined the processes of risk taking and cognitive control as the neural endophenotypes of alcohol dependence. Methods:, To this end, functional magnetic resonance imaging (fMRI) was conducted during a stop signal task (SST), in which a procedure was used to elicit errors in the participants. The paradigm allowed trial-by-trial evaluation of response inhibition, error processing, and post-error behavioral adjustment. Furthermore, by imposing on the subjects to be both fast and accurate, the SST also introduced a distinct element of risk, which participants may or may not avert during the task. Brain imaging data were analyzed with Statistical Parametric Mapping in covariance analyses accounting for group disparity in general performance. Results:, The results showed that, compared to HC, PAD demonstrated longer go trial reaction time (RT) and higher stop success rate (SS%). HC and PAD were indistinguishable in stop signal reaction time (SSRT) and post-error slowing (PES). In a covariance analysis accounting for go trial RT and SS%, HC showed greater activity in the left dorsolateral prefrontal cortex than PAD, when subjects with short and long SSRT were contrasted. By comparing PAD and HC directly during stop errors (SE), as contrasted with SS, we observed greater activity in PAD in bilateral visual and frontal cortices. Compared to HC, PAD showed less activation of the right dorsolateral prefrontal cortex during PES, an index of post-error behavioral adjustment. Furthermore, PAD who showed higher alcohol urge at the time of the fMRI were particularly impaired in dorsolateral prefrontal activation, as compared to those with lower alcohol urge. Finally, compared to HC subjects, PAD showed less activity in cortical and subcortical structures including putamen, insula, and amygdala during risk-taking decisions in the SST. Conclusion:, These preliminary results provided evidence for altered neural processing during impulse control in PAD. These findings may provide a useful neural signature in the evaluation of treatment outcomes and development of novel pharmacotherapy for alcohol dependence. [source]

    Casualty occurrence mechanism in the collapse of timber-frame houses during an earthquake

    EARTHQUAKE ENGINEERING AND STRUCTURAL DYNAMICS, Issue 12 2004
    Junji Kiyono
    Abstract The collapse of timber-frame houses during an earthquake was analyzed by the 2-dimensional (2D) and 3-dimensional (3D) distinct element methods (DEM). The DEM is a numerical analysis technique in which positions of elements are calculated by solving equations of motion step by step. Both individual and group behavior can be simulated. The structure is modeled as an assembly of distinct elements connected by virtual springs and dashpots where elements come into contact. A timber-frame house with simple structural elements; beams, columns, floors, and a roof, was modeled. Injury to human bodies also was considered. Human bodies modeled as circles (2D) or rectangular parallelepipeds (3D) were placed on its floors. The maximum impact acceleration on the human body during an earthquake was calculated. Injury to humans in houses was assessed by the Chest-G index and Head Injury Criteria (HIC) widely used in automobile engineering. Copyright © 2004 John Wiley & Sons, Ltd. [source]

    Prostatic carcinosarcoma: A case report and review of literature

    INTERNATIONAL JOURNAL OF UROLOGY, Issue 2 2003
    TOMOYA FUKAWA
    Abstract A unique case of carcinosarcoma of the prostate detected in a 71-year-old man is presented. Pelvic exenteration was performed, and the resected prostatic mass was found to consist of two histologically distinct elements; adenocarcinoma and sarcoma with focal osteosarcomatous element. The patient is still alive with neither metastasis nor recurrence. This is the 42nd case of carcinosarcoma of the prostate to be reported in the literature. [source]

    THE CEO: A VISIBLE HAND IN WEALTH CREATION?

    JOURNAL OF APPLIED CORPORATE FINANCE, Issue 3 2000
    C. K. Prahalad
    Commensurate with the growth of their pay packages and public visibility, the role of the CEO in the corporate value creation process has increased significantly in recent years. This article argues that sustained wealth creation in a corporation has three distinct elements. The first and most basic is the selection of the lines of business in which to operate; this element is probably the most visible manifestation of CEO action in large corporations today. The second element is the value creation model, which answers the question: How is this particular set of businesses expected to add value over and above the sum of the values of each business or asset category standing alone? The third element is the internal governance system, which establishes the corporate structure and administrative processes of the firm and, perhaps even more important, defines the corporate values that drive the strategic and operational priorities of the different business units. The authors suggest that the essence of the work of the CEO is to develop and maintain a balanced relationship among these three elements of wealth creation and to ensure that the relationship evolves in the face of changing circumstances. CEOs are inevitably faced with dilemmas in managing this process,in particular, the need to balance continuity and change and to maintain the integrity of short-term performance disciplines while encouraging not only investment in growth opportunities (which can hurt near term performance), but also experimentation and collaboration among business units (which are difficult to measure and reward with most performance measurement and incentive schemes). Adding to the difficulties of managing such dilemmas, visibility and a strong public image are often thrust upon (if not sought by) CEOs, who must then determine how they can use that image to strengthen the commitment of their employees and investors. [source]

    Species richness, rarity and endemicity on Italian offshore islands: complementary signals from island-focused and species-focused analyses

    JOURNAL OF BIOGEOGRAPHY, Issue 4 2008
    Leonardo Dapporto
    Abstract Aims, To investigate the relative explanatory power of source faunas and geographical variables for butterfly incidence, frequency, richness, rarity, and endemicity on offshore islands. Location, The western Italian offshore islands (Italy and Malta). Methods, Thirty-one islands were examined. Data were taken from our own field surveys and from the literature. Two approaches were undertaken, described as island-focused and species-focused, respectively. Offshore islands were allocated to their neighbouring source landmasses (Italian Peninsula, Sicily and Sardinia,Corsica) and compared with each other for faunal attributes, source and island geography. Generalized linear and stepwise multiple regression models were then used to determine the relationships of island species richness, rarity and endemicity with potential geographical predictors and source richness, rarity, and endemicity (island-focused). Species frequency and incidence were assessed in relation to geographical and source predictors using stepwise linear and logistic regression, and inter-island associations were examined using K-Means clustering and non-metric scaling (species-focused). Results, The analysis reveals firm evidence for the influence of the nearest large landmass sources on island species assemblages, richness, rarity and endemicity. A clear distinction in faunal affinities occurs between the Sardinian islands and islands lying offshore from the Italian mainland and Sicily. Islands neighbouring these three distinct sources differ significantly in richness, rarity and endemicity. Source richness, rarity, and endemicity have explanatory power for island richness, rarity, and endemicity, respectively, and together with island geography account for a substantial part of the variation in island faunas (richness 59%, rarity 60% and endemicity 64%). Source dominates the logistic regression parameters predicting the incidence of island species [13 (38%) of 34 species that could be analysed]; three ecological factors (source frequency, flight period and maximal altitude at which species live) explained 75% of the variation in the occurrence of species on the islands. Species found more frequently on islands occurred more frequently at sources, had longer flight periods, and occurred at lower altitudes at the sources. The incidence of most species on islands (84%) is correctly predicted by the same three variables. Main conclusions, The Italian region of the Mediterranean Sea has a rich butterfly fauna comprising endemics and rare species as well as more cosmopolitan species. Analysis of island records benefited from the use of two distinct approaches, namely island-focused and species-focused, that sift distinct elements in island and source faunas. Clear contemporary signals appear in island,source relationships as well as historical signals. Differences among faunas relating to sources within the same region caution against assuming that contemporary (ecological) and historical (evolutionary) influences affect faunas of islands in different parts of the same region to the same extent. The implications of source,island relationships for the conservation of butterflies within the Italian region are considered, particularly for the long-term persistence of species. [source]

    Elevating tensor rank increases anisotropy in brain areas associated with intra-voxel orientational heterogeneity (IVOH): a generalised DTI (GDTI) study

    NMR IN BIOMEDICINE, Issue 1 2008
    L. Minati
    Abstract Rank-2 tensors are unable to represent multi-modal diffusion associated with intra-voxel orientational heterogeneity (IVOH), which occurs where axons are incoherently oriented, such as where bundles intersect or diverge. Under this condition, they are oblate or spheroidally shaped, resulting in artefactually low anisotropy, potentially masking reduced axonal density, myelinisation and integrity. Higher rank tensors can represent multi-modal diffusion, and suitable metrics such as generalised anisotropy (GA) and scaled entropy (SE) have been introduced. The effect of tensor rank was studied through simulations, and analysing high angular resolution diffusion imaging (HARDI) data from two volunteers, fit with rank-2, rank-4 and rank-6 tensors. The variation of GA and SE as a function of rank was investigated through difference maps and region of interest (ROI)-based comparisons. Results were correlated with orientation distribution functions (ODF) reconstructed with q-ball, and with colour-maps of the principal and second eigenvectors. Simulations revealed that rank-4 tensors are able to represent multi-modal diffusion, and that increasing rank further has a minor effect on measurements. IVOH was detected in subcortical regions of the corona radiata, along the superior longitudinal fasciculus, in the radiations of the genu of the corpus callosum, in peritrigonal white matter and along the inferior fronto-occipital and longitudinal fascicula. In these regions, elevating tensor rank increased anisotropy. This was also true for the corpus callosum, cingulum and anterior limb of the internal capsule, where increasing tensor rank resulted in patterns that, although mono-modal, were more anisotropic. In these regions the second eigenvector was coherently oriented. As rank-4 tensors have only 15 distinct elements, they can be determined without acquiring a large number of directions. By removing artefactual underestimation of anisotropy, their use may increase the sensitivity to pathological change. Copyright © 2007 John Wiley & Sons, Ltd. [source]

    The Role of Intellectual Property in the Global Challenge for Immunization

    THE JOURNAL OF WORLD INTELLECTUAL PROPERTY, Issue 4 2006
    Tarcísio Hardman Reis
    The contemporary scenario of international immunization is focused on the implementation of vaccination programs in developing countries, which demonstrates obvious similarities with the policy "access to medicines" under the Agreement on Trade-Related Aspects of Intellectual Property Rights. However, the debate on immunization involves distinct elements and presents different concerns and obstacles, which will be presented throughout this study. Three introductory remarks need to be made in order to place intellectual property (IP) as a core problem of global immunization. The first is that immunization is a world priority. The second is that the global immunization challenge faces the hurdle of the poverty gap. Finally, IP plays a controversial role in the implementation of immunization programs in less developed countries. [source]