Exploring rater judging behaviour using the many-facet rasch model

Performance assessment, unlike the traditional fixed-response assessment, has features peculiar to its assessment setting (the task choice, the task processing conditions, the raters,the rating scale, and the rating procedures) that make it much more vulnerable to construct irrelevant variance (McNamara, 1997; Upshur & Turner, 1999). Of these potential sources of variability, those associated with raters are considered to be extensive and pose serious threats to the validity of ratings (Linacre, 1989; McNamara, 1996).For performance assessment to yield valid and reliable results, it is essential that these sources of variability are eliminated or minimized. This paper illustrates how sources of rater-related variability or rater effects can be identified and controlled for using the Many-facet Rasch Model.It also illustrates how the idiosyncratic rating behaviour of individual raters can be explicated through the use of this measurement model. In this illustration, the ratings of thirty-five English language instructors on 12 paragraphs written by new intake students at the Centre for Foundation Studies, IIUM were analysed using FACETS (Linacre, 2003), a computer application which implements the Many-facet Rasch Model. The results of the analysis indicate substantial differences in rater severity, and the presence of other rater effects

Charge-transfer photodissociation of adsorbed molecules via electron image states

The 248nm and 193nm photodissociation of submonolayer quantities of CH$_3$Br and CH$_3$I adsorbed on thin layers of n-hexane indicate that the dissociation is caused by dissociative electron attachment from sub-vacuum level photoelectrons created in the copper substrate. The characteristics of this photodissociation-- translation energy distributions and coverage dependences show that the dissociation is mediated by an image potential state which temporarily traps the photoelectrons near the n-hexane--vacuum interface, and then the charge transfers from this image state to the affinity level of a co-adsorbed halomethane which then dissociates.Comment: submitted to Journal of Chemical Physic

Detection mechanism for ferroelectric domain boundaries with lateral force microscopy

The contrast mechanism for the visualization of ferroelectric domain boundaries with lateral force microscopy is generally assumed to be caused by mechanical deformation of the sample due to the converse piezoelectric effect. We show, however, that electrostatic interactions between the charged tip and the electric fields arising from the surface polarization charges dominate the contrast mechanism. This explanation is sustained by quantitative analysis of the measured forces as well as by comparative measurements on different materials

Pneumatic capillary gun for ballistic delivery of microparticles

A pneumatic gun for ballistic delivery of microparticles to soft targets is proposed and demonstrated. The particles are accelerated by a high speed flow of Helium in a capillary tube. Vacuum suction applied to a concentric, larger diameter tube is used to divert substantially all of the flow of Helium from the gun nozzle, thereby preventing the gas from hitting and damaging the target. Speed of ejection of micron-sized gold particles from the gun nozzle, and their depth of penetration into agarose gels are reported.Comment: 7 pages, 3 figure

ADR and Cyberspace: The Role of Alternative Dispute Resolution in Online Commerce, Intellectual Property and Defamation

Published in cooperation with the American Bar Association Section of Dispute Resolutio

PENGARUH KOMUNIKASI INTERNAL TERHADAP EFEKTIVITAS KERJA PEGAWAI DI PUSAT PENGEMBANGAN DAN PEMBERDAYAAN PENDIDIK DAN TENAGA KEPENDIDIKAN IPA (P4TK IPA) BANDUNG

Penelitian ini berjudul “Pengaruh Komunikasi Internal Terhadap Efektivitas Kerja Pegawai di Pusat Pengembangan dan Pemberdayaan Pendidik dan Tenaga Kependidikan IPA (P4TK IPA) Bandung”. Tujuan penelitian ini adalah untuk menganalisis efektivitas kerja pegawai P4TK IPA Bandung. Fokus permasalahan penelitian ini yaitu untuk memperoleh gambaran secara empiric mengenai pengaruh komunikasi internal terhadapefektivitas kerja pegawai di P4TK IPA Bandung. Berdasarkan hasil perhitungan menunjukkan bahwa rata-rata kecenderungan umum dengan menggunakan Weight Means Score (WMS) untuk variabel X (Komunikasi Internal) yaitu 3,04 , hal ini menunjukkan bahwa variabel X pada kategori sangat baik. Sedangkan rata-rata kecenderungan untuk variabel Y (Efektivitas Kerja Pegawai) yaitu 3,13 , hal ini menunjukkan bahwa variabel Y dikategorikan sangat baik. Analisis koefisen korelasi sebesar 0,586 , yang artinya variabel X berkorelasi cukup kuat terhadap variabel Y. Koefisien determinasi menunjukkan bahwa 34,3% ditentukan oleh komunikasi internal dan sisanya 65,7% ditentukan oleh faktor lain. Berdasarkan hasil pengolahan data dapat disimpulkan bahwa komunikasi internal berpengaruh positif dan signifikan terhadap efektivitas kerja pegawai di Pusat Pengembangan dan Pemberdayaan Pendidik dan Tenaga Kependidikan IPA Bandung. This study entitled "The Influence of Internal Communication on Employee Work Effectiveness at Pusat Pengembangan dan Pemberdayaan Pendidik dan Tenaga Kependidikan IPA (P4TK IPA) Bandung". The purpose of this study was to analyze the effectiveness of employee P4TK IPA Bandung. The focus of this research problem is to obtain empirical description of the influence on the effectiveness of internal communication officer job in P4TK IPA Bandung. Based on the results of the calculations show that the average general tendency to use Means Weight Score (WMS) for the variable X (Internal Communications) is 3.04, indicating that the variable X in the very good category. While the average propensity to variable Y (Employee Work Effectiveness) is 3.13, indicating that the variable Y is categorized very well. Analysis of the correlation coefficient was 0.586, which means that the variable X correlated strongly enough to variable Y. The coefficient of determination indicates that 34,3% of communication is determined by the internal and the remaining 65,7% is determined by other factors. Based on the results of data processing can be concluded that internal communication positive and significant impact on the effectiveness of employees working at the Pusat Pengembangan dan Pemberdayaa

Cavity-Enhanced Rayleigh Scattering

We demonstrate Purcell-like enhancement of Rayleigh scattering into a single optical mode of a Fabry-Perot resonator for several thermal atomic and molecular gases. The light is detuned by more than an octave, in this case by hundreds of nanometers, from any optical transition, making particle excitation and spontaneous emission negligible. The enhancement of light scattering into the resonator is explained quantitatively as an interference effect of light waves emitted by a classical driven dipole oscillator. Applications of our method include the sensitive, non-destructive in-situ detection of ultracold molecules.Comment: v2: 13 pages, 7 figures, small changes to the text, extended description of the theoretical mode

Electronic structure and bonding properties of cobalt oxide in the spinel structure

The spinel cobalt oxide Co3O4 is a magnetic semiconductor containing cobalt ions in Co2+ and Co3+ oxidation states. We have studied the electronic, magnetic and bonding properties of Co3O4 using density functional theory (DFT) at the Generalized Gradient Approximation (GGA), GGA+U, and PBE0 hybrid functional levels. The GGA correctly predicts Co3O4 to be a semiconductor, but severely underestimates the band gap. The GGA+U band gap (1.96 eV) agrees well with the available experimental value (~ 1.6 eV), whereas the band gap obtained using the PBE0 hybrid functional (3.42 eV) is strongly overestimated. All the employed exchange-correlation functionals predict 3 unpaired d electrons on the Co2+ ions, in agreement with crystal field theory, but the values of the magnetic moments given by GGA+U and PBE0 are in closer agreement with the experiment than the GGA value, indicating a better description of the cobalt localized d states. Bonding properties are studied by means of Maximally Localized Wannier Functions (MLWFs). We find d-type MLWFs on the cobalt ions, as well as Wannier functions with the character of sp3d bonds between cobalt and oxygen ions. Such hybridized bonding states indicate the presence of a small covalent component in the primarily ionic bonding mechanism of this compound.Comment: 24 pages, 8 figure