349 research outputs found

    Connectivity-enhanced diffusion analysis reveals white matter density disruptions in first episode and chronic schizophrenia.

    Get PDF
    Reduced fractional anisotropy (FA) is a well-established correlate of schizophrenia, but it remains unclear whether these tensor-based differences are the result of axon damage and/or organizational changes and whether the changes are progressive in the adult course of illness. Diffusion MRI data were collected in 81 schizophrenia patients (54 first episode and 27 chronic) and 64 controls. Analysis of FA was combined with "fixel-based" analysis, the latter of which leverages connectivity and crossing-fiber information to assess both fiber bundle density and organizational complexity (i.e., presence and magnitude of off-axis diffusion signal). Compared with controls, patients with schizophrenia displayed clusters of significantly lower FA in the bilateral frontal lobes, right dorsal centrum semiovale, and the left anterior limb of the internal capsule. All FA-based group differences overlapped substantially with regions containing complex fiber architecture. FA within these clusters was positively correlated with principal axis fiber density, but inversely correlated with both secondary/tertiary axis fiber density and voxel-wise fiber complexity. Crossing fiber complexity had the strongest (inverse) association with FA (r = -0.82). When crossing fiber structure was modeled in the MRtrix fixel-based analysis pipeline, patients exhibited significantly lower fiber density compared to controls in the dorsal and posterior corpus callosum (central, postcentral, and forceps major). Findings of lower FA in patients with schizophrenia likely reflect two inversely related signals: reduced density of principal axis fiber tracts and increased off-axis diffusion sources. Whereas the former confirms at least some regions where myelin and or/axon count are lower in schizophrenia, the latter indicates that the FA signal from principal axis fiber coherence is broadly contaminated by macrostructural complexity, and therefore does not necessarily reflect microstructural group differences. These results underline the need to move beyond tensor-based models in favor of acquisition and analysis techniques that can help disambiguate different sources of white matter disruptions associated with schizophrenia

    Sound archaeology: terminology, Palaeolithic cave art and the soundscape

    Get PDF
    This article is focused on the ways that terminology describing the study of music and sound within archaeology has changed over time, and how this reflects developing methodologies, exploring the expectations and issues raised by the use of differing kinds of language to define and describe such work. It begins with a discussion of music archaeology, addressing the problems of using the term ‘music’ in an archaeological context. It continues with an examination of archaeoacoustics and acoustics, and an emphasis on sound rather than music. This leads on to a study of sound archaeology and soundscapes, pointing out that it is important to consider the complete acoustic ecology of an archaeological site, in order to identify its affordances, those possibilities offered by invariant acoustic properties. Using a case study from northern Spain, the paper suggests that all of these methodological approaches have merit, and that a project benefits from their integration

    Specialized Science High Schools: Exploring Contributions of the Model to Adolescent Talent Development Specialized Science

    Get PDF
    As the field of gifted education shifts much of its focus to domain-specific talent development, specialized science high schools are taking their place on the stage. Back in 1981,Bloom and Sosniak argued persuasively that talent development cannot take place exclusively in schools. They stressed that schools were not prepared to offer the required levels of expert teaching, time, and effort. Yet, specialized science high schools, by design, are staffed with teachers with advanced degrees, offer relatively flexible schedules, interested peers,reasonable access to appropriate technology, and connections with research institutions to provide apprenticeships for the most motivated and interested students

    A density functional theory based analysis of photoinduced electron transfer in a triazacryptand based K+ sensor

    Get PDF
    The electronic structure and photoinduced electron transfer processes in a K+ fluorescent sensor that comprises a 4-amino-naphthalimide derived fluorophore with a triazacryptand lig- and is investigated using density functional theory (DFT) and time-dependent density functional theory (TDDFT) in order to rationalise the function of the sensor. The absorption and emission energies of the intense electronic excitation localised on the fluorophore are accurately described using a ∆SCF Kohn-Sham DFT approach, which gives excitation energies closer to experiment than TDDFT. Analysis of the molecular orbital diagram arising from DFT calculations for the isolated molecule or with implicit solvent cannot account for the function of the sensor and it is necessary to consider the relative energies of the electronic states formed from the local excitation on the fluorophore and the lowest fluorophore→chelator charge transfer state. The inclusion of solvent in these calculations is critical since the strong interaction of the charge transfer state with the solvent lowers it energy below the local fluorophore excited state making a reductive photoinduced electron transfer possible in the absence of K+, while no such process is possible when the sensor is bound to K+. The rate of electron transfer is quantified using Marcus theory, which gives a rate of electron transfer of k_ET=5.98 x 10^6 s−1

    Development of a measure of relationship perception in schizophrenia

    Get PDF
    Relationships Across Domains (RAD) is a new measure of competence in relationship perception that may be used to assess clinically stable persons with schizophrenia and healthy persons. The structure and content of the RAD are grounded in relational models theory, a well-validated theory of social relations. The 75-item RAD contains 25 vignettes and can be administered in approximately 35 min. The RAD requires participants to implicitly identify the relational model of a dyad described in a brief vignette and infer how the members of the dyad are likely to behave in three other social contexts. The RAD demonstrated good internal consistency in schizophrenia outpatients and healthy participants matched to the outpatients in age and education. The schizophrenia outpatients performed more poorly on the RAD than two healthy comparison groups, supporting the ability of the RAD to discriminate between clinical and non-clinical populations. The schizophrenia patients' performance on the RAD was moderately related to reading ability and several domains of community functioning.Psychiatry Research 166(1), 54-62. (2009)0165-178

    Identifying a Typology of High Schools Based on Their Orientation Toward STEM: A Latent Class Analysis of HSLS:09

    Get PDF
    The purpose of this study is to investigate the extent that there is a typology of high schools based on their orientation toward STEM, as well as the extent to which school-level demographic variables and student high school outcomes are associated with subgroup membership in the typology, by analyzing data from a large nationally representative sample of high schools (n=940) from the High School Longitudinal Study of 2009 (HSLS:09) using latent class analysis (LCA). We used a three-step LCA approach to identify significantly different subgroups of STEM-oriented high schools, what covariates predict subgroup membership, and how subgroup membership predicts observed distal outcomes. We find that there are four significantly different subgroups of STEM-oriented high schools based on their principal’s perceptions: Abundant (12.3%), Support (23.3%), Bounded (10.1%), and Comprehensive (54.3%). In addition, we find that these subgroups are associated with school demographics, such as the percent of students eligible for free and reduced-price lunch, school locale, and control (public or private). Subgroup membership is also associated with student outcomes, such as postsecondary program enrollment and intent to pursue a STEM degree. Keywords: STEM Education, High Schools, Multivariate Analysi

    Emotional intelligence in schizophrenia

    Get PDF
    Deficits in emotion perception have been extensively documented in schizophrenia and are associated with poor psychosocial functioning. However, little is known about other aspects of emotion processing that are critical for adaptive functioning. The current study assessed schizophrenia patients' performance on a theoretically-based, well-validated, multidimensional measure of emotional intelligence, the Mayer-Salovey-Caruso Emotional Intelligence Test (Mayer, J.D., Salovey, P., Caruso, D.R., 2002. Mayer-Salovey-Caruso Emotional Intelligence Test (MSCEIT): User's Manual. Multi-Health Systems, Inc., Toronto, Ontario). 50 schizophrenia outpatients and 39 non-psychiatric controls completed the MSCEIT, a performance measure comprised of subtests that assess four components (branches) of emotional intelligence: Identifying, Using, Understanding, and Managing Emotions. Among patients, associations between MSCEIT scores and measures of clinical symptoms as well as functional outcome were evaluated. The MSCEIT demonstrated good psychometric properties in both groups. Schizophrenia patients performed significantly worse than controls on the total MSCEIT score, and on three of the four subtests: Identifying, Understanding, and Managing Emotions. Among patients, lower MSCEIT scores significantly correlated with higher negative and disorganized symptoms, as well as worse community functioning. The MSCEIT is a useful tool for investigating emotion processing in schizophrenia. Individuals with schizophrenia demonstrate deficits across multiple domains of emotion processing. These deficits have significant links with clinical symptoms of schizophrenia and with how patients function in their daily lives. Further research is required to understand the links between emotional intelligence, clinical symptoms, and functional outcome in schizophrenia.Schizophrenia Research 107(1), 61-68. (2008)0920-996

    Insight dimensions and cognitive function in psychosis: a longitudinal study

    Get PDF
    BACKGROUND: It has been reported that lack of insight is significantly associated with cognitive disturbance in schizophrenia. This study examines the longitudinal relationships between insight dimensions and cognitive performance in psychosis. METHODS: Participants were 75 consecutively admitted inpatients with schizophrenia, affective disorder with psychotic symptoms or schizoaffective disorder. Assessments were conducted at two time points during the study: at the time of hospital discharge after an acute psychotic episode and at a follow-up time that occurred more than 6 months after discharge. A multidimensional approach of insight was chosen and three instruments for its assessment were used: the Scale to Assess Unawareness of Mental Disorder (SUMD), three items concerning insight on the Assessment and Documentation in Psychopathology (AMDP) system and the Insight and Treatment Attitudes Questionnaire. The neuropsychological battery included a wide range of tests that assessed global cognitive function, attention, memory, and executive functions. RESULTS: After conducting adequate statistical correction to avoid Type I bias, insight dimensions and cognitive performance were not found to be significantly associated at cross-sectional and longitudinal assessments. In addition, baseline cognitive performance did not explain changes in insight dimensions at follow-up. Similar results were found in the subset of patients with schizophrenia (n = 37). The possibility of a Type II error might have increased due to sample attrition at follow-up. CONCLUSION: These results suggest that lack of insight dimensions and cognitive functioning may be unrelated phenomena in psychosis

    Software for the frontiers of quantum chemistry:An overview of developments in the Q-Chem 5 package

    Get PDF
    This article summarizes technical advances contained in the fifth major release of the Q-Chem quantum chemistry program package, covering developments since 2015. A comprehensive library of exchange–correlation functionals, along with a suite of correlated many-body methods, continues to be a hallmark of the Q-Chem software. The many-body methods include novel variants of both coupled-cluster and configuration-interaction approaches along with methods based on the algebraic diagrammatic construction and variational reduced density-matrix methods. Methods highlighted in Q-Chem 5 include a suite of tools for modeling core-level spectroscopy, methods for describing metastable resonances, methods for computing vibronic spectra, the nuclear–electronic orbital method, and several different energy decomposition analysis techniques. High-performance capabilities including multithreaded parallelism and support for calculations on graphics processing units are described. Q-Chem boasts a community of well over 100 active academic developers, and the continuing evolution of the software is supported by an “open teamware” model and an increasingly modular design
    corecore