Multimethod latent class analysis

Correct and, hence, valid classifications of individuals are of high importance in the social sciences as these classifications are the basis for diagnoses and/or the assignment to a treatment. The via regia to inspect the validity of psychological ratings is the multitrait-multimethod (MTMM) approach. First, a latent variable model for the analysis of rater agreement (latent rater agreement model) will be presented that allows for the analysis of convergent validity between different measurement approaches (e.g., raters). Models of rater agreement are transferred to the level of latent variables. Second, the latent rater agreement model will be extended to a more informative MTMM latent class model. This model allows for estimating (i) the convergence of ratings, (ii) method biases in terms of differential latent distributions of raters and differential associations of categorizations within raters (specific rater bias), and (iii) the distinguishability of categories indicating if categories are satisfyingly distinct from each other. Finally, an empirical application is presented to exemplify the interpretation of the MTMM latent class model

Changes in Sagittal Plane Kinematics and Kinetics after Distal Release of Medial Hamstrings in Cerebral Palsy

published_or_final_versio

Modeling Factors Contributing to Injury and Fatality of Run-off-Road Crashes in Ohio

The main objective of this study was to determine the factors that contribute significantly to the levels of injury severity when run-off-road (ROR) crashes occur. This study used a 5-year crash data for years 2008 - 2012 from the state of Ohio. The decision tree model in conjunction with generalized ordered logit model was used to investigate characteristics of injury and fatality of run-off-road crashes in Ohio. The decision tree modeling was used for exploratory data analysis identified eight factors that explain a large amount of the variation in the response variable, injury severity. These predictor variables include road condition, ROR crash types, posted speed limit, vehicle type, gender, alcohol-related, road contour, and drug-related.. The results from the generalized ordered logit regression show that the following are significant factors in increasing the likelihood of ROR injury severity levels, i.e., incapacitating and fatal injuries: alcohol and drugs use, curves and grades, female victims, overturn/rollover crashes, ROR crashes on dry roadway surfaces. Additionally, buses, truck, and emergency vehicles, and ROR crashes on roadways with posted speed limits of 40 mph or higher increase the probability of injury severity

The Molecular Hydrogen Deficit in Gamma-Ray Burst Afterglows

Recent analysis of five gamma-ray burst (GRB) afterglow spectra reveal the absence of molecular hydrogen absorption lines, a surprising result in light of their large neutral hydrogen column densities and the detection of H$_2$ in similar, more local star-forming regions like 30 Doradus in the Large Magellanic Cloud (LMC). Observational evidence further indicates that the bulk of the neutral hydrogen column in these sight lines lies 100 pc beyond the progenitor and that H$_2$ was absent prior to the burst, suggesting that direct flux from the star, FUV background fields, or both suppressed its formation. We present one-dimensional radiation hydrodynamical models of GRB host galaxy environments, including self-consistent radiative transfer of both ionizing and Lyman-Werner photons, nine-species primordial chemistry with dust formation of H$_2$, and dust extinction of UV photons. We find that a single GRB progenitor is sufficient to ionize neutral hydrogen to distances of 50 - 100 pc but that a galactic Lyman-Werner background is required to dissociate the molecular hydrogen in the ambient ISM. Intensities of 0.1 - 100 times the Galactic mean are necessary to destroy H$_2$ in the cloud, depending on its density and metallicity. The minimum radii at which neutral hydrogen will be found in afterglow spectra is insensitive to the mass of the progenitor or the initial mass function (IMF) of its cluster, if present.Comment: 12 pages, 7 figures, accepted for Ap

Einfluss der Sakrumfraktur auf das funktionelle Langzeitergebnis von Beckenringverletzungen

Zusammenfassung: In der Akutphase umfasst die Behandlung der Beckenringverletzung mit Beteiligung des iliosakralen Komplexes die effiziente Blutungskontrolle und Stabilisierung des Beckenrings. Für das Langzeitresultat sind jedoch neurologische Ausfälle, Fehlverheilungen des hinteren Beckenrings mit tieflumbalen Schmerzen und urologische Komplikationen entscheidend. Zwischen 1991 und 2000 wurden in unserer Klinik 173Patienten mit Sakrumfrakturen behandelt. Diese wurden im Rahmen einer lateralen Kompressionsfraktur (AO-Klassifikation TypB2) oder einer "vertical-shear-" (Typ-C-)Verletzung mit einer Dislokation von 1cm wurden operativ (n=33, 19%) versorgt. 112Patienten wurden nach durchschnittlich 4,9Jahren nachkontrolliert. Von den 39Patienten mit neurologischen Ausfällen (35%) zeigten lediglich 4 eine vollständige neurologische Erholung. Chronische tieflumbale Schmerzen traten selten (n=8, 7%) und nur bei einer Typ-C-Verletzung auf. Die geringe Inzidenz an lumbalen Schmerzen rechtfertigt die konservative Therapie wenig dislozierter (<1cm) Sakrumfrakturen. Entscheidend für das Langzeitergebnis sind neurologische Defizite, die bei 30% aller Patienten persistiere

A market-based approach towards supporting entrepreneurship in developing countries: Assessing the business accelerator model in Egypt

This research aims at exploring the accelerator business model in Egypt, a developing country, and its role as a for-profit organisation in empowering and strengthening opportunity entrepreneurs. After selecting an accelerator for the study, interviews were conducted to demonstrate how the business model operates. Six entrepreneurs that were sponsored by the accelerator were selected according to the nomination of the accelerator. A series of in-depth semi-structured interviews were conducted with the six participant entrepreneurs to gain an understanding about the benefits of being sponsored by the accelerator. In addition, a non-governmental organization was selected to explore how the accelerator model, a for-profit organisation, represents a new and different pathway in promoting opportunity entrepreneurship other than other traditional forms of support

Fatigue in seafarers working in the offshore oil and gas re-supply industry: effects of safety climate, psychosocial work environment and shift arrangement

This study examined the influence of safety climate and psychosocial work environment on the reportedfatigue of seafarers working in the offshore oil and gas re-supply industry (n = 402). We found that seafarerswho reported high psychological demands and perceived the organisational-level safety climate negatively,reported significantly more mental fatigue, physical fatigue, and lack of energy. In addition, seafarers whoreported having high levels of job control reported being significantly less mentally fatigued. We also foundsome combined effects of safety climate and shift arrangement. Organisational-level safety climate did notinfluence the levels of physical fatigue in seafarers working on the night shift. On the contrary, seafarersworking during the days reported to be more physically fatigued when they perceived the organisational-levelclimate to be negative compared with the positive. The opposite effect was found for group-level safetyclimate: seafarers working during the nights reported to be more physically fatigued when they perceivedthe group-level climate to be negative compared with the positive. The results from this study point to theimportance of taking into consideration aspects of the psychosocial work environment and safety climate,and their potential impact on fatigue and safety in the maritime organisations

A cross-cultural comparison of sleep patterns between typically developing children and children with ASD living in Saudi Arabia and the United Kingdom

Background: Sleep is crucial for child development, especially for children with ASD. While it is known that children with ASD experience more severe sleep problems and that these problems tend to persist compared to their typically developing counterparts, these findings tend to come from only Western countries. A cross-cultural study is important to understand if the prevailing understanding of sleep in children with ASD can be extended to different cultural backgrounds. Aim: A cross-cultural study is conducted, involving typically developing children and children with ASD aged 5–12 across two countries: Saudi Arabia and the United Kingdom. Methods and procedures: Using a combination of questionnaires measuring ASD severity (CARS-2), sleep quality (CSHQ), sociodemographic and lifestyle variables and sleep diaries, 244 children were sampled using a mixture of snowball and convenience sampling methods. Outcomes and results: Children with ASD experience more sleep problems compared to typically developing children in Saudi Arabia, and these problems similarly persist across time. Specifically, it was found that children with ASD in Saudi Arabia experience greater sleep onset latency and a greater number of night awakenings. Additionally, across the ASD groups, it was found that children from Saudi Arabia generally experienced poorer sleep than children in the United Kingdom in terms of shorter sleep duration, although children in the United Kingdom tended to report more instances of sleep anxiety and parasomnias. Conclusions and implications: Several reasons such as parental education about sleep hygiene, cultural influences and social hours were put forward as potential explanations for cross-cultural differences. Findings served to emphasise the importance of culturally-appropriate interventions and public education regarding child sleep

Multimethod latent class analysis

Nussbeck FW, Eid M. Multimethod latent class analysis. Frontiers in Psychology. 2015;6: 1332.Correct and, hence, valid classifications of individuals are of high importance in the social sciences as these classifications are the basis for diagnoses and/or the assignment to a treatment. The via regia to inspect the validity of psychological ratings is the multitrait-multimethod (MTMM) approach. First, a latent variable model for the analysis of rater agreement (latent rater agreement model) will be presented that allows for the analysis of convergent validity between different measurement approaches (e.g., raters). Models of rater agreement are transferred to the level of latent variables. Second, the latent rater agreement model will be extended to a more informative MTMM latent class model. This model allows for estimating (i) the convergence of ratings, (ii) method biases in terms of differential latent distributions of raters and differential associations of categorizations within raters (specific rater bias), and (iii) the distinguishability of categories indicating if categories are satisfyingly distinct from each other. Finally, an empirical application is presented to exemplify the interpretation of the MTMM latent class model