Student Evaluation Of Teacher Performance: Random Pre-Destination

The student evaluation, used to measure students’ perceptions of teacher performance, has been increasingly used as the predominant component in assessing teaching effectiveness (Waters et al. 1988), and the widespread movement of outcomes assessment across the country makes this trend likely to continue in the future (McCoy et al. 1994, AACSB 1994, SACS 1995).  Substantial research has been conducted with regard to the reliability and accuracy of student evaluation of teaching quality, and a considerable number of uncontrollable factors are found to bias the results of the evaluation rating.  This paper identifies one more factor.  Each student has an “evaluator profile”, which decreases the reliability of the student evaluation.  An “evaluator profile” is a persistent pattern of evaluating behavior that may or may not be consistent with the quality of the characteristic being evaluated.  Each class of students consists of a random sample of different evaluator profiles.  A student evaluation rating of a teacher’s performance is biased up or down depending on the concentration of high or low evaluator profiles present.  This paper further shows through simulation the degree to which student “evaluator profiles” impact the overall student evaluation rating of teacher performance. We find that there is evidence to support the “evaluator profile” conjecture, and that these “evaluator profiles” do in fact have the potential to change overall student evaluation ratings substantially

Red Emission Of Thin Film Electroluminescent Device Based On p-GaN.

High quality GaN layers doped with Mg were grown on Si(111) substrates using high temperature AlN as buffer layer by using radio-frequency molecular beam epitaxy (RF-MBE)

Optical Characterization Of GaN Thin Film Grown On Si(111) By Radio-Frequency Plasma-Assisted Molecular Beam Epitaxy.

The wide band gap gallium nitride (GaN) based semiconductor system has great potential for applications in high-power, high-frequency, and hightemperature optoelectronic devices due to its superior properties, such as large breakdown field, high electron mobility, and thermal stability at elevated temperature

Trans-boundary variations of urban drought vulnerability and its impact on water resource management in Singapore and Johor, Malaysia

Low-latitude areas generally experience relatively large precipitation totals, but droughts/dry spells do occur periodically and are potentially hazardous in these regions - especially within rapidly developing urban settlements. These areas typically have high water demand and therefore may potentially be subjected to water scarcity. Effective local water resource management lowering risks and vulnerabilities to drought is thus paramount, and these policies may be affected in regions with national borders sharing a common transboundary water resource. In this study, we (a) quantify and identify drought episodes using the Palmer Drought Severity Index in the neighbouring equatorial regions of Singapore and Johor, Malaysia, and (b) qualitatively examine each region's drought impacts and consequent responses through archival research over the past fifty years. The data indicate that both frequencies and intensities of drought episodes in both Singapore and Johor have increased over time, suggesting greater exposure to this hazard. However, there are distinct variations in drought impacts in Singapore and Johor, and how each region addresses water resource management to drought with varying degrees of success. Despite the close geographical proximity, significant variations in regional adaptive capacities suggest that different drought vulnerabilities exist. We discuss the efficacy of drought responses over different time scales, and suggest that a combination of demand- and supply-side policies, especially in the long-term, should be considered to reduce vulnerability to this hazard.Published versio

Surface Morphology And Formation Of Nanostructured Porous GaN By UV-Assisted Electrochemical Etching.

This article reports on the studies of porous GaN .prepared by ultra-violet (UV) assisted electrochemical etching in a solution of 4:1:1 HF: CH30H:H202 under illumination of an UV lamp with 500 W power for 10, 25 and 35 minutes

Metastatic Crohn's Disease of the Ear

Objective. We reported a very rare case of metastatic Crohn's disease involving the retro-auricular region. Method. A case report and a review of literature concerning metastatic Crohn's disease. Results. Metastatic Crohn's disease is an uncommon extraintestinal cutaneous manifestation of Crohn's disease and a very rare case involving the retro-auricular region is reported here. Given the limited existing literature little is known about this condition. The skin lesions appear to have a predilection for the lower trunk and genitalia regions. There is no clear association with the severity of Crohn's disease and in some cases, the cutaneous lesions predate the onset of gastrointestinal Crohn's disease. Treatment with immune-modulating medications together with the antitumour necrosis factor monoclonal antibody therapy appears to offer the best chance of remission. Conclusion. By reporting this interesting and rare condition we also hope to highlight the importance of considering underlying chronic systemic disorders, such as Crohn's disease, when presented with skin lesions resistant to simple local treatments

Antimicrobial activities of plant extracts against methicillin-susceptible and methicillin-resistant Staphylococcus aureus

The present study was carried out to compare the antimicrobial activities of methanol leaf extracts of Bauhinia purpurea, Dicranopterislinearis, Melastomamalabathricum and Muntingiacalabura portrayed by different antimicrobial assays against methicillin-susceptible and methicillin- resistant Staphylococcus aureus strains. Antimicrobial activities of the methanol leaf extracts were preliminarily screened by disc diffusion. Minimum inhibition concentration (MIC) and minimum bactericidal concentration (MBC) were determined by broth microdilution and colorimetric assay (resazurin). Based on disc diffusion method, S. aureusATCC®700699™ (MRSA) elucidated higher susceptibility pattern against all plant extracts compared to S. aureusATCC®25923™ (MSSA). Taking results from all employed assays into consideration, M. calaburamethanol leaf extract comparably elicited the highest antimicrobial activity than the other methanol leaf extracts against both microorganisms. The MIC values were determined by colorimetric assay (resazurin) due to pigmentations of the methanol leaf extracts that obscured visual growth turbidity inspection. Complication in colour changes observation in colorimetric assay to determine MBC was overcome by employing the conventional plating method. This study suggested that all antimicrobial assays should be carried out concurrently so as the data obtained can be comparatively analysed for a better outcome as each antimicrobial assay has its own shortfall

Optimization of torrefaction conditions for high energy density solid biofuel from oil palm biomass and fast growing species available in Malaysia

Without appropriate treatment, lignocellulosic biomass is not suitable to be fed into existing combustion systems because of its high moisture content, low bulk energy density and difficulties in transport, handling and storage. The aim of this study was to investigate the effects of torrefaction treatment on the weight loss and energy properties of fast growing species in Malaysia (Acacia spp., and Macaranga spp.) as well as oil palm biomass (oil palm trunk and empty fruit bunch). The lignocellulosic biomass was torrefied at three different temperatures 200, 250 and 300 °C for 15, 30 and 45 min. Response surface methodology was used for optimization of torrefaction conditions, so that biofuel of high energy density, maximized energy properties and minimum weight loss could be manufactured. The analyses showed that increase in heating values was affected by treatment severity (cumulated effect of temperature and time). Our results clearly demonstrated an increased degradation of the material due to the combined effects of temperature and treatment time. While the reaction time had less impact on the energy density of torrefied biomass, the effect of reaction temperature was considerably stronger under the torrefaction conditions used in this study. It was demonstrated that each biomass type had its own unique set of operating conditions to achieve the same product quality. The optimized torrefaction conditions were verified empirically and applicability of the model was confirmed. The torrefied biomass occurred more suitable than raw biomass in terms of calorific value, physical and chemical properties. The results of this study could be used as a guide for the production of high energy density solid biofuel from lignocellulosic biomass available in Malaysia

Analysis of Four Historical Ciphers Against Known Plaintext Frequency Statistical Attack

The need of keeping information securely began thousands of years. The practice to keep the information securely is by scrambling the message into unreadable form namely ciphertext. This process is called encryption. Decryption is the reverse process of encryption. For the past, historical ciphers are used to perform encryption and decryption process. For example, the common historical ciphers are Hill cipher, Playfair cipher, Random Substitution cipher and Vigenère cipher. This research is carried out to examine and to analyse the security level of these four historical ciphers by using known plaintext frequency statistical attack. The result had shown that Playfair cipher and Hill cipher have better security compare with Vigenère cipher and Random Substitution cipher