The Links in our Mind:Multivariate Statistical Methods for Psychological Data

Psychopathological processes are characterized by multiple interacting dimensions, that in order to be understood properly have to be studied simultaneously. In this thesis multivariate statistical methods, such as item response theory and graphical models, have been proposed to model psychological observables for explaining complex mental phenomena. After introducing the chronology of multivariate analysis in the behavioural sciences, we describe mixed graphical models for cross-sectional data from two cohort studies, in order to study the relationship between functional somatic symptoms and psychotic experiences in adolescence. Then we focus on the statistical modelling of psychological time-series data and specifically on the class of Graphical Vector Autoregressive (GVAR) models. We implemented GVARs in open-source software that can be used for fitting these models to psychological data with different characteristics. Next, we apply the GVAR to time series data from psychopathology for studying the development of psychosis according to subsequent stages of illness severity. The topic of multivariate time series analysis in psychopathology is concluded by a newly developed hierarchical extension of the traditional GVAR model. This extension can be used for modelling simultaneously time series data from multiple individuals taking into account individual heterogeneity. The thesis is concluded with a software implementation of the nonparametric item response theory model for unfolding processes MUDFOLD, which has been extended to provide uncertainty quantification in parameter estimation using bootstrap, and which handles missing values using multiple imputation by chained equations

Dynamic symptom networks across different at-risk stages for psychosis:An individual and transdiagnostic perspective

The clinical staging model distinguishes different stages of mental illness. Early stages, are suggested to be more mild, diffuse and volatile in terms of expression of psychopathology than later stages. This study aimed to compare individual transdiagnostic symptom networks based on intensive longitudinal data between individuals in different early clinical stages for psychosis. It was hypothesized that with increasing clinical stage (i) density of symptom networks would increase and (ii) psychotic experiences would be more central in the symptom networks. Data came from a 90-day diary study, resulting in 8640 observations within N = 96 individuals, divided over four subgroups representing different early clinical stages (n1 = 25, n2 = 27, n3 = 24, n4 = 20). Sparse Time Series Chain Graphical Models were used to create individual contemporaneous and temporal symptom networks based on 10 items concerning symptoms of depression, anxiety, psychosis, non-specific and vulnerability domains. Network density and symptom centrality (strength) were calculated individually and compared between and within the four subgroups. Level of psychopathology increased with clinical stage. The symptom networks showed large between-individual variation, but neither network density not psychotic symptom strength differed between the subgroups in the contemporaneous (pdensity = 0.59, pstrength > 0.51) and temporal (pdensity = 0.75, pstrength > 0.35) networks. No support was found for our hypothesis that higher clinical stage comes with higher symptom network density or a more central role for psychotic symptoms. Based on the high inter-individual variability, our results highlight the importance of individualized assessment of symptom networks

The “Cloud” Europe and Germany as the European Stabilizer

AbstractSince the global economic crisis emerged, the European Union confronts several and substantial challenges in its roots. The fundamental European vision of stability, growth, prosperity and economic convergence seems to be at stake, mainly, by the citizens of the countries that suffer from the consequences of lengthy austerity measures and economic recession. The European Union itself changed since 2009. As the Franco-German axis is crumbling, Germany – even reluctantly for some analysts – became the essential leading force in the EU and hard fiscal policies dazzled bright characteristics of the EU. Intergovernmental controversies are coming at the front of the stage once again. We argue that is time for the European Union to seek for another approach of itself, an approach beyond the narrow intergovernmental processes, beyond even the “spill-over effect” model that guided the monetary unification. The aim of this paper is to draw the “cloud Europe” approach, show its characteristics and attributes. The “cloud Europe” scheme, based upon the “cloud Computing” characteristics from the field of ICTs, can stimulate again the European vision, and revitalize the European cooperation in terms of positive and reliable aspects and not just in terms of heavy fiscal discipline. We use a theoretical adaptation from the ICTs’ area to the political field of the European organization and successful cases of best practices such as the progress of Estonia towards the digital economy and the growth of digital infrastructures. The leading role of Germany in an approach like that can turn the country into a European stabilizer

mudfold: An R Package for Nonparametric IRT Modelling of Unfolding Processes

Abstract Item response theory (IRT) models for unfolding processes use the responses of individuals to attitudinal tests or questionnaires in order to infer item and person parameters located on a latent continuum. Parametric models in this class use parametric functions to model the response process, which in practice can be restrictive. MUDFOLD (Multiple UniDimensional unFOLDing) can be used to obtain estimates of person and item ranks without imposing strict parametric assumptions on the item response functions (IRFs). This paper describes the implementation of the MUDFOLD method for binary preferential-choice data in the R package mudfold. The latter incorporates estimation, visualization, and simulation methods in order to provide R users with utilities for nonparametric analysis of attitudinal questionnaire data. After a brief introduction in IRT, we provide the method ological framework implemented in the package. A description of the available functions is followed by practical examples and suggestions on how this method can be used even outside the field of psychometrics

Optimizing CO2 field flooding during sternotomy: In vitro confirmation of the Karolinska studies.

Although CO2 field-flooding was first used during cardiac surgery more than 60 years ago, its efficacy is still disputed. The invisible nature of the gas and the difficulty in determining the "safe" quantity to protect the patient are two of the main obstacles to overcome for its validation. Moreover, CO2 concentration in the chest cavity is highly sensitive to procedural aspects, such suction and hand movements. Based on our review of the existing literature, we identified four major factors that influence the intra-cavity CO2 concentration during open-heart surgery: type of delivery device (diffuser), delivery CO2 flow rate, diffuser position around the wound cavity, and its orientation inside the cavity. In this initial study, only steady state conditions were considered to establish a basic understanding on the effect of the four above-mentioned factors. Transient factors, such as suction or hand movements, will be reported separately

Differential impact of transfusion guidelines on blood transfusion practices within a health network

Abstract Whether clinical practice guidelines have a significant impact on practice is unclear. The effect of guideline recommendations on clinical practice often a lags behind the date of publication. We evaluated by means of a data-driven approach if and when the guidelines on red blood cell transfusions (RBCTs) issued by Swiss Smarter Medicine in 2016 had an impact on RBCTs practice within a hospital network, where awareness of guidelines was promoted mainly among internal medicine specialties. Data on RBCTs performed in a Swiss hospital network from January 2014 to April 2021 were analyzed by hospital site and specialty to assess whether guidelines led to a decrease in inappropriate RBCTs. RBCTs were defined as “inappropriate” if patients had a hemoglobin level ≥ 70 g/L without or ≥ 80 g/L with significant cardiovascular comorbidities. Changes in the rate of inappropriate transfusions were analyzed with an advanced statistical approach that included generalized additive models. Overall prior to March 2017 there were more inappropriate than appropriate RBCTs, but after October 2017 the opposite could be observed. A change-point in the time trend was estimated from transfusion data to occur in the time interval between March and October 2017. This change was mainly driven by practice changes in the medical wards, while no significant change was observed in the critical care, surgical and oncology wards. Change in practice varied by hospital site. In conclusion, our results show that a significant change in the RBCTs practice at the hospital level occurred approximately 18 months after national guidelines were issued

Tetrathiomolybdate Complexes of Rhodium(I) with Molybdenum–Rhodium Interactions

Producción CientíficaThe synthesis and characterization of the tetrathiomolybdatorhodium(I) monoanionic complexes [L2Rh(μ-S)2MoS2]− (L = CO (3), P(OPh)3 (4), P(O-o-Tol)3 (P(o-CH3C6H4)3; 5), P(OMe)3 (6), P(OEt)3 (7), P(O-i-Pr)3 (8); L2 = COD (1,5-cyclooctadiene; 2), cis-dppen (cis-Ph2PCH═CHPPh2; 9), dppe (Ph2PCH2CH2PPh2; 10), dppb (Ph2P(CH2)4PPh2; 11)) is presented. The complex 2 (NEt4+ salt) was characterized by X-ray diffraction analysis. A detailed DFT study of the electronic structures of 2–4 and 6–8 has revealed the existence of extended electron delocalization over the four-membered Rh(μ-S)2Mo ring and hence the possibility of electronic communication between the metal centers. The electronic spectra were studied with TDDFT calculations, and the main absorption band in the visible region was assigned to ν(Rh→Mo) electron transfer transition, which is actually a HOMO–LUMO transition. The ν(Rh→Mo) transition was found to correlate linearly both with Tolman’s electronic parameter of the phosphite ligands and the calculated HOMO–LUMO gap of the complexes, rendering it a well-defined ligand electronic parameter, which describes the net donating ability of monodentate and bidentate ligands (CO, COD, phosphites, diphosphines). The study of the variation of Δδ(31P) and 1J(Rh–P) of the phosphite complexes with respect to the QALE model electronic parameters χd, πp, and Ear has succeeded in the assessment of the σ and π effects on these NMR spectral parameters