Index optimisation for structural equation models (SEM)

Structural equation modelling (SEM), a statistical technique used extensively in quantitative marketing research and other domains, is an analytical approach used to model latent (unobservable) variables. Unlike distribution fitting where simple chi-squared goodness-of-fit assessment yields satisfactory results, model fit in SEM is more difficult. Descriptive goodness-of-fit indices have been developed over the past 50 years to assist in the assessment of model fit. The traditional assessment method requires reporting multiple indices, all of which should reflect an adequate model fit in order for the overall model fit to be deemed good. The choice of indices to report are left to the researcher’s discretion, leading to the indices used to differ considerably. The combination of using the traditional assessment method and differing indices often lead to conflicting results. This study proposes a composite index, combining frequently used indicators in an attempt to obtain a single index method for assessing model fit in SEM that performs better when compared to the traditional assessment method. Composite indices have been used in other domains as an improved method of assessing performance (Barr and Kantor, 2004). The composite index proposed is evaluated using a Monte Carlo simulation study under different experimental conditions. The experimental conditions investigated are sample size, estimation method and model misspecification. These experimental conditions are chosen to investigate as each has been shown to affect the traditional indices performances. The ideal fit indices should be able to detect model misspecification while being insensitive to sample size and estimation methods. This is not always the case with the traditional indices. The composite index proposed is shown to outperform the traditional assessment method under many of the experimental condition combinations. This provides evidence that composite indices may be a more beneficial method of assessing model fit in SEM

Best Practices for Vulnerable Adult Investigation Policies and Procedures at Blue Earth County

The purpose of this project is to update the policies and procedures for conducting vulnerable adult investigations in Blue Earth County to reflect changes in the statute and to incorporate current best practices for conducting investigations

Table of Contents and Prologue

Editorial board, Table of contents, and Prologue, an introduction to volume 1

Coupled Rotary and Oscillatory Motion in a Second-Generation Molecular Motor Pd Complex

Molecular machines offer many opportunities for the development of responsive materials and introduce autonomous motion in molecular systems. While basic molecular switches and motors carry out one type of motion upon being exposed to an external stimulus, the development of molecular systems capable of performing coupled motions is essential for the development of more advanced molecular machinery. Overcrowded alkene-based rotary molecular motors are an ideal basis for the design of such systems as they undergo a controlled rotation initiated by light allowing for excellent spatio-temporal precision. Here, we present an example of a Pd complex of a second-generation rotary motor whose Pd center undergoes a coupled oscillatory motion relative to the motor core upon rotation of the motor. We have studied this phenomenon by UV-vis, NMR, and density functional theory calculations to support our conclusions. With this demonstration of a coupled rotation-oscillation motion powered by a light-driven molecular motor, we provide a solid basis for the development of more advanced molecular machines integrating different types of motion in their operation

Regulation of wild-type and mutant p53 activity

The tumour suppressor p53 is extensively regulated by posttranslational modification, including modification by the small Ubiquitin-related modifier SUMO. The data presented here show that MDM2, previously described to promote Ubiquitin, Nedd8 and SUMO-1 modification of p53, can also enhance conjugation of endogenous SUMO-2/3 to p53. SUMOylation activity requires p53-MDM2 binding but does not depend on an intact RING finger. Both p14ARF and L11 can promote SUMO-2/3 conjugation of p53. However, unlike the previously described SUMO-1 conjugation of p53 by an MDM2-p14ARF complex, this activity does not depend on the ability of MDM2 to relocalise to the nucleolus. Strikingly, the SUMO consensus is not conserved in mouse p53, which is therefore not modified by SUMO-2/3. Ultimately, conjugation of SUMO-2/3 to p53 correlates with a reduction of both activation and repression of a subset of p53 target genes and guides the p53 response towards apoptosis rather than cell cycle arrest. Roughly 30% of all cancers express a p53 protein containing a single amino acid exchange within the DNA binding domain. These mutant p53 proteins not only lose wild-type p53 function, but also gain new oncogenic properties that partially reflect the ability of mutant p53 to interact with and repress the p53-family transcription factors p63 and p73. Like wild-type p53, mutant p53 is also SUMOylated by MDM2, but SUMO-2/3 modification does not affect mutant p53’s ability to interact with p63 and p73. p63 and p73 bind to the DNA binding domain of mutant p53, although these interactions do not require an aggregation domain that has been identified around isoleucine 254 within this region of p53. While the DNA binding domain of p73 is necessary for binding to mutant p53, the core domain of p63 is dispensable for the interaction with mutant p53. The p53-binding protein MDM2 binds TAp73α and ∆Np73α, but does not interact with TAp63α or ∆Np63α. Strikingly, addition of MDM2 to mutant p53-p73 complexes leads to the formation of a trimeric complex with MDM2, while addition of MDM2 to mutant p53-p63 complexes releases p63 from the inhibitory mutant p53 interaction. Altogether, this study reveals ubiquitination-independent mechanisms, by which MDM2 influences both wild-type and mutant p53 activity

Asymmetric Synthesis of Chiral-at-P Alkenylphosphonamidates through Nickel-Catalyzed C-P Coupling of Phosphoramidites and Alkenyl Halides

P-stereogenic compounds are widely used as ligands in asymmetric catalysis and are present in a myriad of bioactive compounds and pharmaceuticals. Yet, their stereocontrolled preparation remains challenging. Herein, we report a novel strategy towards versatile chiral-at-P alkenylphosphonamidates through a one-pot Ni-catalyzed C-P coupling/diastereoselective hydrolysis of readily available phosphoramidites and alkenyl halides. Remarkably, a chemo- and diastereodivergent behavior was observed upon subtle changes in the reaction conditions. Additionally, selective derivatizations of chiral alkenylphosphonamidates demonstrate their versatility as building blocks for the synthesis of structurally diverse P-stereogenic compounds.</p

Evaluation of the protein quality of fish meals by means of the NPU method

No Abstrac

Chunks in Chemie- und Physikaufgaben - Zusammenhang zwischen Gedächtniskapazität und Aufgabenkomplexität

Der Zusammenhang zwischen der Gedächtniskapazität von Lernenden und der Komplexität einer gestellten Aufgabe wurde in den 1980er Jahren durch Johnstone und El-Banna untersucht. Die Ergebnisse sind richtungsweisend für die Gestaltung von Aufgaben, gerieten jedoch im Laufe der Jahre besonders in Deutschland weitgehend in Vergessenheit. Im vorliegenden Artikel werden die Inhalte dieser Studie von Chemie- auf Physikaufgaben übertragen.Von 16 Studierenden der Technischen Universität Braunschweig wurden die Gedächtniskapazitäten bestimmt und diese mit den Ergebnissen eines Testes in Beziehung gesetzt, der aus sieben unterschiedlich schwierigen physikalischen Aufgaben bestand. Folgende These wurde dabei untersucht: Die Überlastung des Arbeitsgedächtnisses einer Testperson ist dafür verantwortlich, dass bestimmte Aufgaben nicht gelöst werden können. Schülerinnen / Schüler bzw. Studierende mit einer Gedächtniskapazität von X Chunks (englisch: Klumpen oder Brocken) können nur Aufgaben mit einer Anzahl von maximal Z Lösungsschritten bearbeiten, wenn Z ≤ X gilt.Trotz der geringen Teilnehmerzahl konnten die Ergebnisse von Johnstone und El-Banna reproduziert werden. Ein Zusammenhang zwischen Gedächtniskapazität und Aufgabenkomplexität ist klar erkennbar

The Influence of Strain on the Rotation of an Artificial Molecular Motor

In artificial small-molecule machines, molecular motors can be used to perform work on coupled systems by applying a mechanical load—such as strain—that allows for energy transduction. Here, we report how ring strain influences the rotation of a rotary molecular motor. Bridging the two halves of the motor with alkyl tethers of varying sizes yields macrocycles that constrain the motor's movement. Increasing the ring size by two methylene increments increases the mobility of the motor stepwise and allows for fine-tuning of strain in the system. Small macrocycles (8–14 methylene units) only undergo a photochemical E/Z isomerization. Larger macrocycles (16–22 methylene units) can perform a full rotational cycle, but thermal helix inversion is strongly dependent on the ring size. This study provides systematic and quantitative insight into the behavior of molecular motors under a mechanical load, paving the way for the development of complex coupled nanomachinery

Chunks in Chemie- und Physikaufgaben - Zusammenhang zwischen Gedächtniskapazität und Aufgabenkomplexität

Der Zusammenhang zwischen der Gedächtniskapazität von Lernenden und der Komplexität einer gestellten Aufgabe wurde in den 1980er Jahren durch Johnstone und El-Banna untersucht. Die Ergebnisse sind richtungsweisend für die Gestaltung von Aufgaben, gerieten jedoch im Laufe der Jahre besonders in Deutschland weitgehend in Vergessenheit. Im vorliegenden Artikel werden die Inhalte dieser Studie von Chemie- auf Physikaufgaben übertragen.Von 16 Studierenden der Technischen Universität Braunschweig wurden die Gedächtniskapazitäten bestimmt und diese mit den Ergebnissen eines Testes in Beziehung gesetzt, der aus sieben unterschiedlich schwierigen physikalischen Aufgaben bestand. Folgende These wurde dabei untersucht: Die Überlastung des Arbeitsgedächtnisses einer Testperson ist dafür verantwortlich, dass bestimmte Aufgaben nicht gelöst werden können. Schülerinnen / Schüler bzw. Studierende mit einer Gedächtniskapazität von X Chunks (englisch: Klumpen oder Brocken) können nur Aufgaben mit einer Anzahl von maximal Z Lösungsschritten bearbeiten, wenn Z ≤ X gilt.Trotz der geringen Teilnehmerzahl konnten die Ergebnisse von Johnstone und El-Banna reproduziert werden. Ein Zusammenhang zwischen Gedächtniskapazität und Aufgabenkomplexität ist klar erkennbar