High-accuracy peak picking of proteomics data

A new peak picking algorithm for the analysis of mass spectrometric (MS) data is presented. It is independent of the underlying machine or ionization method, and is able to resolve highly convoluted and asymmetric signals. The method uses the multiscale nature of spectrometric data by first detecting the mass peaks in the wavelet-transformed signal before a given asymmetric peak function is fitted to the raw data. In an optional third stage, the resulting fit can be further improved using techniques from nonlinear optimization. In contrast to currently established techniques (e.g. SNAP, Apex) our algorithm is able to separate overlapping peaks of multiply charged peptides in ESI-MS data of low resolution. Its improved accuracy with respect to peak positions makes it a valuable preprocessing method for MS-based identification and quantification experiments. The method has been validated on a number of different annotated test cases, where it compares favorably in both runtime and accuracy with currently established techniques. An implementation of the algorithm is freely available in our open source framework OpenMS (www.open-ms.de)

Complementary and competing factor analytic approaches for the investigation of measurement invariance

Sample-related invariance is an important topic in psychometric research. The generalizability of findings in a broad range of application samples requires equivalence of interpretations based on the measurement outcomes across respective samples. Contextual factors like gender, age, culture, ethnicity, socio-economical status etc. may affect the meaning and interpretation of psychological measures. Sample-related invariance is frequently investigated using Multiple-Group Mean and Covariance Structure (MGMCS) analyses. This method builds upon natural or artifical categories of contextual variables. Many contextual variables are continuous variables and their categorization is associated with an information loss and potentially overly simplistic data analyses. We present and discuss two complementary analytical approaches – Latent Moderated Structural (LMS) Equations and Local Structural Equation Models (LSEM). Both approaches allow treating contextual factors as continuous variables and are appropriate to detect non-linear relations. The use of these methods is exemplified based on real data. We investigated measurement equivalence of a battery of cognitive tests across age (N = 448; age range 18-82 years). Based on a higher-order factor model of cognitive abilities factorial equivalence could be established – contradicting the age-dedifferentiation hypothesis. Advantages and disadvantages of MGMCS, LMS, and LSEM and further implementations beyond aging-research are discussed

Examining age-related shared variance between face cognition, vision, and self-reported physical health: a test of the common cause hypothesis for social cognition

The shared decline in cognitive abilities, sensory functions (e.g., vision and hearing), and physical health with increasing age is well documented with some research attributing this shared age-related decline to a single common cause (e.g., aging brain). We evaluate the extent to which the common cause hypothesis predicts associations between vision and physical health with social cognition abilities specifically face perception and face memory. Based on a sample of 443 adults (17–88 years old), we test a series of structural equation models, including Multiple Indicator Multiple Cause (MIMIC) models, and estimate the extent to which vision and self-reported physical health are related to face perception and face memory through a common factor, before and after controlling for their fluid cognitive component and the linear effects of age. Results suggest significant shared variance amongst these constructs, with a common factor explaining some, but not all, of the shared age-related variance. Also, we found that the relations of face perception, but not face memory, with vision and physical health could be completely explained by fluid cognition. Overall, results suggest that a single common cause explains most, but not all age-related shared variance with domain specific aging mechanisms evident

A Micro-Typology of Contact Effects in Four Tibeto-Burman Languages

When minority languages with similar typological profiles are in long-term contact with a genealogically unrelated socioeconomically dominant language, the perfect context is provided for investigating which observed contact effects are demonstrably allied to sociolinguistic dynamics rather than purely structural ones. This paper investigates the factors determining the different extent of contact effects in four Tibeto-Burman languages (Gurung, Gyalsumdo, Nar-Phu, and Manange) spoken in a geo-politically defined and multilingual region of Nepal. Using corpus data and sociolinguistic interviews collected in the field, we demonstrate that a range of social, economic and geo-spatial factors contribute to asymmetries where contact effects are observed in the four speech communities. These notably include factors specifically relevant in mountain-based communities, including proximity to transport and trekking routes, outward migration effects on small settlements, and the primary economies of the different parts of the Manang District

NAD(H)-coupled hydrogen cycling - structure-function relationships of bidirectional [NiFe] hydrogenases

Hydrogenases catalyze the activation or production of molecular hydrogen. Due to their potential importance for future biotechnological applications, these enzymes have been in the focus of intense research for the past decades. Bidirectional [NiFe] hydrogenases are of particular interest as they couple the reversible cleavage of hydrogen to the redox conversion of NAD(H). In this account, we review the current state of knowledge about mechanistic aspects and structural determinants of these complex multi-cofactor enzymes. Special emphasis is laid on the oxygen-tolerant NAD(H)-linked bidirectional [NiFe] hydrogenase from Ralstonia eutropha. (C) 2011 Federation of European Biochemical Societies. Published by Elsevier B. V. All rights reserved

Determining factors for compensatory movements of the left arm and shoulder in violin playing

IntroductionDespite a large number of available ergonomic aids and recommendations regarding instrument positioning, violin players at any proficiency level still display a worrying incidence of task-specific complaints of incompletely understood etiology. Compensatory movement patterns of the left upper extremity form an integral part of violin playing. They are highly variable between players but remain understudied despite their relevance for task-specific health problems.MethodsThis study investigated individual position effects of the instrument and pre-existing biomechanical factors likely determining the degree of typical compensatory movements in the left upper extremity: (1) left elbow/upper arm adduction (“Reference Angle α”, deviation from the vertical axis), (2) shoulder elevation (“Coord x”, in mm), and (3) shoulder protraction (“Coord y”, in mm). In a group of healthy music students (N = 30, 15 m, 15 f, mean age = 22.5, SD = 2.6), “Reference Angle α” was measured by 3D motion capture analysis. “Coord x” and “Coord y” were assessed and ranked by a synchronized 2D HD video monitoring while performing a pre-defined 16-s tune under laboratory conditions. These three primary outcome variables were compared between four typical, standardized violin positions varying by their sideward orientation (“LatAx-CSP”) and/or inclination (“LoAx-HP”) by 30°, as well as the players’ usual playing position. Selected biomechanical hand parameter data were analyzed as co-factors according to Wagner’s Biomechanical Hand Measurement (BHM).ResultsMean “Reference Angle α” decreased significantly from 24.84 ± 2.67 to 18.61 ± 3.12° (p < 0.001), “Coord x” from 22.54 ± 7.417 to 4.75 ± 3.488 mm (p < 0.001), and “Coord y” from 5.66 ± 3.287 to 1.94 ± 1.901) mm (p < 0.001) when increasing LatAx-CSP and LoAx-HP by 30°. Concerning the biomechanical co-factors, “Reference Angle α”, “Coord y”, but not “Coord x”, were found to be significantly increased overall, with decreasing passive supination range (r = −0.307, p = <0.001 for “Passive Supination 250 g/16Ncm”, and r = −0.194, p = <0.001 for “Coord y”). Compensatory movements were larger during tune sections requiring high positioning of the left hand and when using the small finger.DiscussionResults may enable to adapt individually suitable instrument positions to minimize strenuous and potentially unhealthy compensation movements of the left upper extremity

Individual Differences in the Speed of Facial Emotion Recognition Show Little Specificity but Are Strongly Related with General Mental Speed: Psychometric, Neural and Genetic Evidence

Facial identity and facial expression processing are crucial socio-emotional abilities but seem to show only limited psychometric uniqueness when the processing speed is considered in easy tasks. We applied a comprehensive measurement of processing speed and contrasted performance specificity in socio-emotional, social and non-social stimuli from an individual differences perspective. Performance in a multivariate task battery could be best modeled by a general speed factor and a first-order factor capturing some specific variance due to processing emotional facial expressions. We further tested equivalence of the relationships between speed factors and polymorphisms of dopamine and serotonin transporter genes. Results show that the speed factors are not only psychometrically equivalent but invariant in their relation with the Catechol-O Methyl-Transferase (COMT) Val158Met polymorphism. However, the 5-HTTLPR/rs25531 serotonin polymorphism was related with the first-order factor of emotion perception speed, suggesting a specific genetic correlate of processing emotions. We further investigated the relationship between several components of event-related brain potentials with psychometric abilities, and tested emotion specific individual differences at the neurophysiological level. Results revealed swifter emotion perception abilities to go along with larger amplitudes of the P100 and the Early Posterior Negativity (EPN), when emotion processing was modeled on its own. However, after partialling out the shared variance of emotion perception speed with general processing speed-related abilities, brain-behavior relationships did not remain specific for emotion. Together, the present results suggest that speed abilities are strongly interrelated but show some specificity for emotion processing speed at the psychometric level. At both genetic and neurophysiological levels, emotion specificity depended on whether general cognition is taken into account or not. These findings keenly suggest that general speed abilities should be taken into account when the study of emotion recognition abilities is targeted in its specificity

Web-based audiovisual patient information system—a study of preoperative patient information in a neurosurgical department

Background: In the current climate of increasing awareness, patients are demanding more knowledge about forthcoming operations. The patient information accounts for a considerable part of the physician's daily clinical routine. Unfortunately, only a small percentage of the information is understood by the patient after solely verbal elucidation. To optimise information delivery, different auxiliary materials are used. Methods: In a prospective study, 52 consecutive stationary patients, scheduled for an elective lumbar disc operation were asked to use a web-based audiovisual patient information system. A combination of pictures, text, tone and video about the planned surgical intervention is installed on a tablet personal computer presented the day before surgery. All patients were asked to complete a questionnaire. Results: Eighty-four percent of all participants found that the audiovisual patient information system lead to a better understanding of the forthcoming operation. Eighty-two percent found that the information system was a very helpful preparation before the pre-surgical interview with the surgeon. Ninety percent of all participants considered it meaningful to provide this kind of preoperative education also to patients planned to undergo other surgical interventions. Eighty-four percent were altogether "very content” with the audiovisual patient information system and 86% would recommend the system to others. Conclusions: This new approach of patient information had a positive impact on patient education as is evident from high satisfaction scores. Because patient satisfaction with the informed consent process and understanding of the presented information improved substantially, the audiovisual patient information system clearly benefits both surgeons and patient

Evaluating the Impact of an Accountable Care Organization on Population Health: The Quasi-Experimental Design of the German Gesundes Kinzigtal.

A central goal of accountable care organizations (ACOs) is to improve the health of their accountable population. No evidence currently links ACO development to improved population health. A major challenge to establishing the evidence base for the impact of ACOs on population health is the absence of a theoretically grounded, robust, operationally feasible, and meaningful research design. The authors present an evaluation study design, provide an empirical example, and discuss considerations for generating the evidence base for ACO implementation. A quasi-experimental study design using propensity score matching in combination with small-scale exact matching is implemented. Outcome indicators based on claims data were constructed and analyzed. Population health is measured by using a range of mortality indicators: mortality ratio, age at time of death, years of potential life lost/gained, and survival time. The application is assessed using longitudinal data from Gesundes Kinzigtal, one of the leading population-based ACOs in Germany. The proposed matching approach resulted in a balanced control of observable differences between the intervention (ACO) and control groups. The mortality indicators used indicate positive results. For example, 635.6 fewer years of potential life lost (2005.8 vs. 2641.4; t-test: sig. P < 0.05*) in the ACO intervention group (n = 5411) attributable to the ACO, also after controlling for a potential (indirect) immortal time bias by excluding the first half year after enrollment from the outcome measurement. This empirical example of the impact of a German ACO on population health can be extended to the evaluation of ACOs and other integrated delivery models of care

A Descent Method for Equality and Inequality Constrained Multiobjective Optimization Problems

In this article we propose a descent method for equality and inequality constrained multiobjective optimization problems (MOPs) which generalizes the steepest descent method for unconstrained MOPs by Fliege and Svaiter to constrained problems by using two active set strategies. Under some regularity assumptions on the problem, we show that accumulation points of our descent method satisfy a necessary condition for local Pareto optimality. Finally, we show the typical behavior of our method in a numerical example