Keller’s “Old” Personalized System of Instruction: A “New” Solution for Today’s College Chemistry Students

This article examines a long-dormant teaching methodology known as the Personalized System of Instruction (PSI). The literature documenting the effectiveness of PSI is reviewed, showing that it is superior to traditional instruction. Even given this evidence, few educators employ this instructional strategy today. Arguments against PSI are examined, and suggestions are made on how to avoid the pitfalls associated with PSI. The article also discusses how to implement PSI in a college chemistry course.     

Polarization-dependent EXAFS in bromine-doped polyacetylene

The local dopant structure was investigated in stretch-oriented (CHBr_y)_x at 77 K by polarization dependent EXAFS measurements at the Br-K edge. Definite nn Br-C and Br-Br distances are derived and nnn distances are tentatively assigned. The data clearly show that a large portion of Br intercalates in form of linear Br^-₃ (or longer Br^-_2n+1) molecules with the molecular axis parallel to the (CH)_x chains. Two models for the local dopant structure are proposed and discussed on the basis of other experimental results.     

QED corrections to the evolution of parton distributions

We study the systematic inclusion of QED corrections in the evolution of parton distributions. corrections modify the evolution equation for parton distributions. They introduce additional parton distributions, like the photon distribution in the nucleon, and lead to additional mixing effects. We discuss the modifications for a realistic model of N_f,up up-type flavours and N_f,down down-type flavours. We have implemented these corrections into a numerical program and we quantify the size of these effects in a toy model. The corrections reach the order of 1%.     

Optical constants and vibrational assignment of liquid toluene-d8 between 4000 and 450 cm at 25 °C

The optical constants (real and imaginary refractive indices) and imaginary molar polarizability spectrum of liquid toluene-d₈ are presented for the first time. The spectra were determined between 4000 and 450 cm⁻¹ at 25 °C. The fundamentals of toluene-d₈ in the liquid phase are revisited with the aid of gas phase spectra of toluene and toluene-d₈, ab initio calculations, and previously reported liquid assignments of toluene.     

Eingebrannte dünne Metallfilme als Widerstandsthermometer für Wärmeübergangsmessungen

Zusammenfassung Es wird eine Technik beschrieben zur Herstellung und Anwendung dünner eingebrannter Metallfilme als Widerstandsthermometer. Diese eignen sich zur Messung von Oberflächentemperaturen bei der experimentellen Untersuchung von Wärmeübertragungsproblemen. Im beschriebenen Anwendungsfall der Kondensation wurde eine Meßgenauigkeit von ±0,023 K erreicht.

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Thin films of fired metal paints as resistance thermometers for heat transfer measurements

A technique is described for manufacturing and applying thin fired metal-paint-films as resistance thermometers. They can be used for measurement of surface temperatures in experimental investigations of heat transfer problems. In the described case of condensation the accuracy of measurement was ±0.023 K.

     

Fermeture des opérateurs dissipatifs invariants

Sans résumé     

Institutional Norms and Policies That Influence College Mathematics Professors in the Process of Changing to Reform‐Based Practices

This case study was an investigation of the role of the institutional culture of a university in the process of changing to reform‐based practices for two college mathematics professors. A framework is presented for identifying and analyzing institutional norms and policies that are present and those lacking in supporting faculty efforts toward reform. The primary categories considered in the framework are the teaching and learning context, the professional community, and the university's reward system. This framework is applied to the cases, and findings indicate that institutional norms in the forms of priorities for how time is allocated to professional responsibilities (as part of the teaching context), and colleagues and administrators who understood and shared the professors' goals for reform (as part of the professional community) strongly influenced the professors' efforts toward change. Additionally, a reward system that recognized efforts to improve teaching and learning was critical in establishing a culture that promoted change. However, despite the fact that both professors were in the same mathematics department, the nature of the influence of these factors was not uniform. The institutional culture indeed had multiple layers that required examination for each professor's individual context. The findings help highlight the importance of institutional context for both K‐12 and college level teaching and learning. The nature of these influential factors and the institutional layers were discussed for each case, along with implications for other institutions.