43 research outputs found
HBT: A (mostly) experimental overview
I will present a review of the field of Hanbury Brown-Twiss interferometry in
relativistic heavy-ion collisions. The "HBT puzzle" is explored in detail,
emphasizing recent theoretical attempts to understand the persisting puzzle. I
also present recent experimental results on azimuthally sensitive HBT, HBT of
direct photons, and some surprises in the comparison of HBT results from p+p
and Au+Au collisions at RHIC.Comment: 8 pages, 3 figures. Proceedings of the Quark Matter 2004 conference
(Oalkland, CA, USA, January 2004
Quality assurance and quality control reporting in untargeted metabolic phenotyping: mQACC recommendations for analytical quality management
Background Demonstrating that the data produced in metabolic phenotyping investigations (metabolomics/metabonomics) is of good quality is increasingly seen as a key factor in gaining acceptance for the results of such studies. The use of established quality control (QC) protocols, including appropriate QC samples, is an important and evolving aspect of this process. However, inadequate or incorrect reporting of the QA/QC procedures followed in the study may lead to misinterpretation or overemphasis of the findings and prevent future metanalysis of the body of work. Objective The aim of this guidance is to provide researchers with a framework that encourages them to describe quality assessment and quality control procedures and outcomes in mass spectrometry and nuclear magnetic resonance spectroscopy-based methods in untargeted metabolomics, with a focus on reporting on QC samples in sufficient detail for them to be understood, trusted and replicated. There is no intent to be proscriptive with regard to analytical best practices; rather, guidance for reporting QA/QC procedures is suggested. A template that can be completed as studies progress to ensure that relevant data is collected, and further documents, are provided as on-line resources. Key reporting practices Multiple topics should be considered when reporting QA/QC protocols and outcomes for metabolic phenotyping data. Coverage should include the role(s), sources, types, preparation and uses of the QC materials and samples generally employed in the generation of metabolomic data. Details such as sample matrices and sample preparation, the use of test mixtures and system suitability tests, blanks and technique-specific factors are considered and methods for reporting are discussed, including the importance of reporting the acceptance criteria for the QCs. To this end, the reporting of the QC samples and results are considered at two levels of detail: âminimalâ and âbest reporting practiceâ levels
Current commands for high-efficiency torque control of DC shunt motor
The current commands for a high-efficiency torque control of a DC shunt motor are described. In the proposed control method, the effect of a magnetic saturation and an armature reaction are taken into account by representing the coefficients of an electromotive force and a torque as a function of the field current, the armature current and the revolving speed. The current commands at which the loss of the motor drive system becomes a minimum are calculated as an optimal problem. The proposed control technique of a motor is implemented on the microprocessor-based control system. The effect of the consideration of the magnetic saturation and the armature reaction on the produced torque and the minimisation of the loss are discussed analytically and experimentally </p
Beyond the Global Brain Differences:Intraindividual Variability Differences in 1q21.1 Distal and 15q11.2 BP1-BP2 Deletion Carriers
BACKGROUND: Carriers of the 1q21.1 distal and 15q11.2 BP1-BP2 copy number variants exhibit regional and globalbrain differences compared with noncarriers. However, interpreting regional differences is challenging if a globaldifference drives the regional brain differences. Intraindividual variability measures can be used to test for regionaldifferences beyond global differences in brain structure.METHODS: Magnetic resonance imaging data were used to obtain regional brain values for 1q21.1 distal deletion (n =30) and duplication (n = 27) and 15q11.2 BP1-BP2 deletion (n = 170) and duplication (n = 243) carriers and matchednoncarriers (n = 2350). Regional intra-deviation scores, i.e., the standardized difference between an individualâsregional difference and global difference, were used to test for regional differences that diverge from the globaldifference.RESULTS: For the 1q21.1 distal deletion carriers, cortical surface area for regions in the medial visual cortex, posterior cingulate, and temporal pole differed less and regions in the prefrontal and superior temporal cortex differedmore than the global difference in cortical surface area. For the 15q11.2 BP1-BP2 deletion carriers, cortical thicknessin regions in the medial visual cortex, auditory cortex, and temporal pole differed less and the prefrontal andsomatosensory cortex differed more than the global difference in cortical thickness.CONCLUSIONS: We find evidence for regional effects beyond differences in global brain measures in 1q21.1 distaland 15q11.2 BP1-BP2 copy number variants. The results provide new insight into brain profiling of the 1q21.1 distaland 15q11.2 BP1-BP2 copy number variants, with the potential to increase understanding of the mechanismsinvolved in altered neurodevelopment
ENIGMA and global neuroscience: A decade of large-scale studies of the brain in health and disease across more than 40 countries
This review summarizes the last decade of work by the ENIGMA (Enhancing NeuroImaging Genetics through Meta Analysis) Consortium, a global alliance of over 1400 scientists across 43 countries, studying the human brain in health and disease. Building on large-scale genetic studies that discovered the first robustly replicated genetic loci associated with brain metrics, ENIGMA has diversified into over 50 working groups (WGs), pooling worldwide data and expertise to answer fundamental questions in neuroscience, psychiatry, neurology, and genetics. Most ENIGMA WGs focus on specific psychiatric and neurological conditions, other WGs study normal variation due to sex and gender differences, or development and aging; still other WGs develop methodological pipelines and tools to facilitate harmonized analyses of "big data" (i.e., genetic and epigenetic data, multimodal MRI, and electroencephalography data). These international efforts have yielded the largest neuroimaging studies to date in schizophrenia, bipolar disorder, major depressive disorder, post-traumatic stress disorder, substance use disorders, obsessive-compulsive disorder, attention-deficit/hyperactivity disorder, autism spectrum disorders, epilepsy, and 22q11.2 deletion syndrome. More recent ENIGMA WGs have formed to study anxiety disorders, suicidal thoughts and behavior, sleep and insomnia, eating disorders, irritability, brain injury, antisocial personality and conduct disorder, and dissociative identity disorder. Here, we summarize the first decade of ENIGMA's activities and ongoing projects, and describe the successes and challenges encountered along the way. We highlight the advantages of collaborative large-scale coordinated data analyses for testing reproducibility and robustness of findings, offering the opportunity to identify brain systems involved in clinical syndromes across diverse samples and associated genetic, environmental, demographic, cognitive, and psychosocial factors
A Nondegenerate Code of Deleterious Variants in Mendelian Loci Contributes to Complex Disease Risk
SummaryAlthough countless highly penetrant variants have been associated with Mendelian disorders, the genetic etiologies underlying complex diseases remain largely unresolved. By mining the medical records of over 110 million patients, we examine the extent to which Mendelian variation contributes to complex disease risk. We detect thousands of associations between Mendelian and complex diseases, revealing a nondegenerate, phenotypic code that links each complex disorder to a unique collection of Mendelian loci. Using genome-wide association results, we demonstrate that common variants associated with complex diseases are enriched in the genes indicated by this âMendelian code.â Finally, we detect hundreds of comorbidity associations among Mendelian disorders, and we use probabilistic genetic modeling to demonstrate that Mendelian variants likely contribute nonadditively to the risk for a subset of complex diseases. Overall, this study illustrates a complementary approach for mapping complex disease loci and provides unique predictions concerning the etiologies of specific diseases
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S21. THE IMPACT OF PERSISTENT NEGATIVE SYMPTOMS ON FUNCTIONING AND DEFEATIST BELIEFS IN YOUTH AT CLINICAL HIGH RISK FOR PSYCHOSIS
Abstract Background Persistent negative symptoms (PNS) are defined as enduring moderate negative symptoms while controlling for principal sources of secondary negative symptoms. PNS symptoms have been associated with poor functional outcomes in schizophrenia. Furthermore, in schizophrenia negative symptoms and poor functioning have been reportedly associated with defeatist beliefs (e.g., âI always failâ). Youth at clinical high risk (CHR) for developing psychosis often demonstrate negative symptoms, poor functioning, and defeatist beliefs. The goal of this study was to determine if negative symptoms were associated with poor functioning and defeatist beliefs in a CHR longitudinal cohort. Methods CHR (N=764) participants were recruited for the North American Prodrome Longitudinal Study (NAPLS 2) at 8-sites across North America. Negative symptoms were rated on the Scale of Prodromal Symptoms (SOPS) at baseline, 6, 12, 18, and 24 months. For this study negative symptoms were restricted to social anhedonia (N1), avolition (N2), and expression of emotion (N3) based on recommendations from the NIMH-MATRICS consensus statement on negative symptoms. PNS were defined as having one of these three negative symptoms scored â„4 (i.e., moderately severe to extreme) for a period of one year. Depressive symptoms were assessed with the Calgary Depression Scale for Schizophrenia (CDSS). To assess defeatist beliefs the Brief Core Schema Scale (BCSS) was utilized as a proxy to evaluate negative self-beliefs (e.g., âI am worthlessâ) and positive self-beliefs (e.g., âI am valuableâ). Generalized linear mixed models for repeated measures were used to examine changes over time between and within groups to accommodate for missing data and account for intra-participant correlations. Results Sixty-seven CHR individuals had PNS. Mixed-effect models demonstrated that the PNS group had significant global, social, and role functioning deficits at baseline, 6, 12, 18, and 24 months compared to CHR individuals without PNS (n=673). Moreover, functioning did not improve in the PNS group while functioning in the group without PNS significantly improved over time. There were no significant differences between the groups on depressive symptoms with the CDSS. The PNS group had significantly higher BCSS self-negative beliefs at 12 and 24 months compared to the group without PNS. Individuals without PNS had significantly higher positive self-beliefs (e.g., âI am valuableâ) at baseline, 6 months, 12 months and 24 months compared to the PNS group. Discussion The results indicate that in the NAPLS cohort 10% of CHR individuals have PNS. Moreover, the PNS group demonstrated significant and persistent global, social, and role functioning deficits compared to those without PNS. The group without PNS had higher levels of positive beliefs (e.g., âI am successfulâ), which may indicate a protective factor against developing PNS