A cross-cultural investigation into students' evaluation of university teaching

This study uses the applicability paradigm of Marsh (1981) to examine the validity of two evaluation instruments and their underlying model of teaching effectiveness across seven countries with diverse cultures and higher education systems. The results from the seven studies support the reliability, appropriateness, and to some degree convergent and discriminant validities of the two instruments. Similar patterns of item salience and discrimination between good and poor lecturers are also obtained. Hence, the similarity of the results from diverse academic settings generally lends support to the applicability and the cross-cultural validity of these two instruments and their underlying model of teaching. In addition, the finding that Hong Kong, Taiwan, and China are each relatively more similar to the West than among themselves may reflect the fact that their higher education systems are to a certain extent modeled after those of the West.published_or_final_versio

The Berkeley Dry Eye Flow Chart: A fast, functional screening instrument for contact lens-induced dryness.

PurposeIn this article, we introduce a novel flow chart-based screening tool for the categorization of contact lens-induced dryness (CLIDE) and its impact on daily visual activities: the Berkeley Dry Eye Flow Chart (DEFC).MethodsOne hundred thirty (130) experienced soft contact lens wearers discontinued lens wear for 24 hrs, passed a baseline screening and eye health examination, completed the Ocular Surface Disease Index (OSDI) then were dispensed fresh pairs of their habitual lenses. After 6 hrs of wear, subjects were administered a battery of symptom questionnaires, and underwent non-invasive tear breakup time (NITBUT) measurement, grading of distortion in reflected topographer mires, grading of lens surface wettability, and a fluorescein examination of the ocular surface. Subjects returned after at least 48 hrs and repeated all assessments after 6 hrs of wear of a second fresh pair of habitual lenses.ResultsThe repeatability of the DEFC between visits was within 1%, and Limits of Agreement and Coefficient of Repeatability were comparable to those of the other CLIDE assessments. Higher DEFC score was significantly related to shorter pre-lens NITBUT, higher OSDI score, and higher Visual Analog Scale (VAS) ratings of average and end-of-day severity and frequency of dryness (all p < 0.001). For CLIDE as diagnosed based on DEFC score, the highest sensitivities and specificities were achieved by the OSDI and VAS ratings; pre-lens NITBUT exhibited good sensitivity but poor specificity. The optimum pre-lens NITBUT diagnostic threshold was found to be ≤ 2.0 sec for debilitating CLIDE, and the OSDI threshold was ≥ 11.4.ConclusionsThe DEFC provides a means of quickly categorizing CLIDE patients based on severity and frequency of symptoms, and on the degree to which symptoms impact daily life. The DEFC has several potential advantages as a CLIDE screening and monitoring tool, has good repeatability, and is significantly related to commonly employed clinical assessments for CLIDE

Thermal stability of ultrahard polycrystalline diamond composite materials

Thermal stability of the ultrahard polycrystalline diamond (UHPCD) composite material developed by the reinforcement of the polycrystalline diamond (PCD) with chemical vapor deposition (CVD) diamond has been investigated in a flow of argon at 1200 °C. The indentation, Raman spectra and wear test have been performed to compare hardness, C–C structure and wear resistance of untreated and thermal treated UHPCD. It has been shown that the hardness of CVD diamond in UHPCD attains 133±7 GPa after high pressure and high temperature, while after thermal treatment the hardness decreases to 109±3 GPa, and the wear resistance of the thermal treated UHPCD decreases from 0.17 to 0.6 mg/km. The narrowing of full width at half maximum and shift of Raman peak to lower frequencies of CVD diamond in thermal treated UHPCD imply a decrease of crystal structural defects and compressive stresses, which results in a drop of the hardness of CVD diamond in a thermal treated UHPCD. The higher wear rate of thermal treated UHPCD is due to the lower hardness.Досліджено термічну стабільність надтвердого полікристалічного алмазного (UHPCD) композиційного матеріалу, отриманого армуванням полікристалічного алмазу після хімічного осадження (CVD) алмазу в потоці аргону при 1200 °C. Для порівняння твердості, C–C-структури і зносостійкості необробленого та термообробленого UHPCD було досліджено заглиблення індентора, спектри комбінаційного розсіювання та знос. Показано, що твердість CVD-алмазу в UHPCD досягає 133±7 ГПа після дії високого тиску і високої температури, а після термообробки зменшується до 109±3 ГПа, зносостійкість UHPCD після термообробки зменшується від 0,17 до 0,6 мг/км. Звуження напівширини і зсув піку комбінаційного розсіювання в область низьких частот CVD-алмазу в термообробленому UHPCD характеризує зменшення кристалічних структурних дефектів і напружень стиску, що призводить до зниження твердості CVD-алмазу в термообробленому UHPCD. Вища швидкість зносу термообробленого UHPCD пов’язана з більш низькою твердістю.Исследована термическая стабильность сверхтвердого поликристаллического алмазного (UHPCD) композиционного материала, полученного армированием поликристаллического алмаза после химического осаждения (CVD) алмаза в потоке аргона при 1200 °C. Для сравнения твердости, C–C-структуры и износостойкости необработанного и термообработанного UHPCD были исследованы глубина проникновения индентора, спектры комбинационного рассеяния и износ. Показано, что твердость CVD-алмаза в UHPCD достигает 133±7 ГПа после действия высокого давления и высокой температуры, а после термической обработки уменьшается до 109±3 ГПа, износостойкость после термической обработки UHPCD уменьшается от 0,17 до 0,6 мг/км. Сужение полуширины и сдвиг пика комбинационного рассеяния в область низких частот CVD- алмаза в термообработанном UHPCD характеризует уменьшение кристаллических структурных дефектов и напряжений сжатия, что приводит к снижению твердости CVD-алмаза в термообработанном UHPCD. Более высокая скорость износа термически обработанного UHPCD связана с более низкой твердостью

Effects of corneoscleral topography on soft contact lens performance: A pilot study.

To quantify corneoscleral junction (CSJ) topography in soft contact lens (SCL) wearers, and assess the association between the CSJ and SCL performance and subjective comfort, forty-four adapted SCL wearers (16 Asians, 16 Caucasians, 12 Latinos) were recruited for the present study. Corneal topography was taken with a Medmont E300 (Medmont International, Pty Ltd.). CSJ images were taken with a commercial OCT (Bioptigen, Inc.). Our published CSJ image analysis technique was used to describe the geometric properties of the CSJ using the sum of squared orthogonalized residuals (SSRo). Multivariable mixed effects models were employed to examine associations between SSRo and subject demographics, ocular characteristics, SCL fit and performance, and comfort. The SSRo was significantly related to quadrant (p < 0.001), ethnicity (p = 0.014), and horizontal corneal shape factor (p = 0.044). The nasal quadrant had the largest SSRo, indicating the steepest CSJ profile and/or the most irregular CSJ surface, followed by the inferior quadrant. The superior and temporal quadrants had the smallest SSRo, indicating relatively flat and even CSJ topography. Caucasians had the steepest and/or most irregular CSJ compared with Latinos and Asians. Less inferior-superior heterogeneity in the SSRo was associated with greater comfort after 6 h of lens wear. The SSRo was proved to be a useful tool to quantify CSJ geometry in SCL wearers. Significant differences in the SSRo were found among quadrants and ethnic groups. Better subjective comfort after 6 h of SCL wear was associated with a smaller difference in the SSRo between the superior and inferior quadrants

Clinical assessment of a customized free-form progressive add lens spectacle.

PurposeTo determine whether there are significant differences in standard clinical measures of vision, progressive addition lens (PAL)-specific vision tests, or subjective ratings and preferences between customized free-form and standard non-free-form PALs in an experienced wearing population. In addition, we aim to determine whether subjective or objective clinical outcomes depend on demographic, PAL usage, spectacle prescription, or frame fitting characteristics.MethodsIn a randomized, double-masked cross-over trial, 95 experienced wearers wore Zeiss Individual customized free-form PAL spectacles (test) and standard non-free-form PAL spectacles (control) for 1 week each. At dispensing and after 1 week of wear, subjects were tested for distance and near visual acuity under both high and low contrast; in addition, 30° off-axis visual acuity was measured using a novel apparatus, as was the horizontal extent of clear, undistorted vision at reading distance. Subjects also completed a set of questionnaires detailing their satisfaction levels, adaptation times, and preferences for test or control spectacles for different visual tasks.ResultsThe test spectacles were preferred overall and for distance, midrange, transitional and active vision, and rated higher in overall satisfaction (p = 0.006). There were no clinically important differences between test and control spectacles in standard clinical vision assessments. In the PAL-specific assessments, however, the horizontal extent of clear vision at reading distance was significantly greater with the test spectacles (p = 0.004).ConclusionsThere were statistically significant preferences for the optically customized free-form lenses over the non-free-form lenses. Subjects also reported a wider field of undistorted vision when looking through the reading zone of the test spectacles. Although standard clinical vision assessments are not sufficiently refined to detect important objective differences between the spectacle types, customization taking into account back vertex distance, segment height, pantoscopic tilt, and wrap angle can result in a superior subjective wearing experience for many PAL patients

Conjunctival epithelial flap in continuous contact lens wear.

PurposeComposed of sheets of cells detached from the underlying conjunctiva, conjunctival epithelial flap (CEF) is a recently reported phenomenon associated with contact lens wear with potential consequences for ocular health. Although CEF is generally asymptomatic, it is not known to what extent it might increase the longer-term risk of discomfort, inflammatory response, or infection. In this study, we use survival analysis methods to obtain unbiased estimates of the probability of developing CEF, the mean survival time free of CEF, and the effects of age, gender, ethnicity, and contact lens type.MethodsTwo hundred four subjects were recruited for a continuous wear (CW) study of silicone hydrogel (SiH) and gas permeable (GP) contact lenses. Subjects were examined by optometrists throughout contact lens adaptation and CW periods. Statistical methods included the Kaplan-Meier nonparametric estimator of the survival function and the Cox proportional hazards model for estimating the relative effects of covariates.ResultsOf the 204 subjects, 72 (35%) developed CEF. In 64% of cases, CEFs were observed bilaterally. The majority of cases (90.3%) presented with CEF in the superior conjunctiva. Mean survival time free of CEF was longer for GP lenses (94.3 days) than for SiH lenses (76.5 days), and the probability of developing CEF was significantly greater for SiH lenses (p = 0.002). Although there was some evidence that women and non-Asians remain free of CEF longer, the effects of age, gender, and ethnicity were not statistically significant.ConclusionsThere was a significantly increased risk of CEF in subjects wearing SiH lenses, compared with GP lenses. Subjects wearing SiH lenses remained free of CEF for a shorter time on average. Further study is needed to determine whether the increased incidence of CEF in CW with SiH lenses poses an increased risk of adverse ocular response or infection

Formation of robust and completely tunable resonant photonic band gaps

We identify different types of the photonic band gaps (PBGs) of two dimensional magnetic photonic crystals (MPCs) consisting of arrays of magnetic cylinders and study the different tunability (by an external static magnetic field) of these PBGs. One type of the band gaps comes from infinitely degenerate flat bands and is closely related to those in the study of plasmonics. In addition, such PBGs are magnetically tunable and robust against position disorder. We calcualte the transmission of the PBG's and found excellent agreement with the results of the photonic band structure calculation. Positional disorder of the lattice structure affects the different types of PBGs differently.Comment: 4 pages, 5 figure

BPS R-balls in N=4 SYM on R X S^3, Quantum Hall Analogy and AdS/CFT Holography

In this paper, we propose a new approach to study the BPS dynamics in N=4 supersymmetric U(N) Yang-Mills theory on R X S^3, in order to better understand the emergence of gravity in the gauge theory. Our approach is based on supersymmetric, space-filling Q-balls with R-charge, which we call R-balls. The usual collective coordinate method for non-topological scalar solitons is applied to quantize the half and quarter BPS R-balls. In each case, a different quantization method is also applied to confirm the results from the collective coordinate quantization. For finite N, the half BPS R-balls with a U(1) R-charge have a moduli space which, upon quantization, results in the states of a quantum Hall droplet with filling factor one. These states are known to correspond to the ``sources'' in the Lin-Lunin-Maldacena geometries in IIB supergravity. For large N, we find a new class of quarter BPS R-balls with a non-commutativity parameter. Quantization on the moduli space of such R-balls gives rise to a non-commutative Chern-Simons matrix mechanics, which is known to describe a fractional quantum Hall system. In view of AdS/CFT holography, this demonstrates a profound connection of emergent quantum gravity with non-commutative geometry, of which the quantum Hall effect is a special case.Comment: 42 pages, 2 figures; v3: a new paragraph on counting unbroken susy of NC R-balls and references adde

Effects of eye rubbing and breath holding on corneal biomechanical properties and intraocular pressure.

PurposeTo determine whether corneal biomechanical properties and intraocular pressure (IOP) are affected by eye rubbing and breath holding.MethodsCorneal hysteresis, corneal resistance factor, corneal compensated IOP (IOPcc), and Goldmann equivalent IOP (IOPg) were measured on both eyes of 40 subjects. Measurements were taken at baseline before eye rubbing (ER(0)) and before breath holding (BH(0)), immediately after 2 episodes of eye rubbing (ER(1) and ER(2)), and during 2 episodes of breath holding (BH(1) and BH(2)).ResultsCorneal hysteresis, corneal resistance factor, and IOPg were significantly lower after ER(1) compared with ER(0) and were significantly lower after ER(2) compared with ER(1). In contrast, IOPcc did not decrease significantly. There were no significant differences among BH(0), BH(1), and BH(2) in any of the 4 outcomes.ConclusionsEye rubbing should be avoided before measurements of corneal biomechanical properties and IOPg. In contrast, breath holding during measurements is not likely to cause a significant change in IOPg and IOPcc or corneal biomechanical properties