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Inferior Performance (inferior + performance)
Selected AbstractsEvaluation of sorbent amendments for in situ remediation of metal-contaminated sedimentsENVIRONMENTAL TOXICOLOGY & CHEMISTRY, Issue 9 2010Seokjoon Kwon Abstract The present study evaluated sorbent amendments for in situ remediation of sediments contaminated with two divalent metals. A literature review screening was performed to identify low-cost natural mineral-based metal sorbents and high-performance commercial sorbents that were carried forward into laboratory experiments. Aqueous phase metal sorptivity of the selected sorbents was evaluated because dissolved metals in sediment porewater constitute an important route of exposure to benthic organisms. Based on pH-edge sorption test results, natural sorbents were eliminated due to inferior performance. The potential as in situ sediment amendment was explored by comparing the sorption properties of the engineered amendments in freshwater and saltwater (10 PPT salinity estuarine water) matrices. Self-assembled monolayers on mesoporous supports with thiols (Thiol-SAMMSÔ) and a titanosilicate mineral (ATSÔ) demonstrated the highest sorption capacity for cadmium (Cd) and lead (Pb), respectively. Sequential extraction tests conducted after mixing engineered sorbents with contaminated sediment demonstrated transfer of metal contaminants from a weakly bound state to a more strongly bound state. Biouptake of Cd in a freshwater oligochaete was reduced by 98% after 5-d contact of sediment with 4% Thiol-SAMMS and sorbed Cd was not bioavailable. While treatment with ATS reduced the small easily extractable portion of Pb in the sediment, the change in biouptake of Pb was not significant because most of the native lead was strongly bound. The selected sorbents added to sediments at a dose of 5% were mostly nontoxic to a range of sensitive freshwater and estuarine benthic organisms. Metal sorbent amendments in conjunction with activated carbon have the potential to simultaneously reduce metal and hydrophobic contaminant bioavailability in sediments. Environ. Toxicol. Chem. 2010;29:1883,1892. © 2010 SETAC [source] Effect of augmented visual feedback from a virtual reality simulation system on manual dexterity trainingEUROPEAN JOURNAL OF DENTAL EDUCATION, Issue 1 2005E. Wierinck Little research has been published about the impact of simulation technology on the learning process of novel motor skills. Especially the role of augmented feedback (FB) on the quality of performance and the transfer of the acquired behaviour to a no-augmented FB condition require further investigation. Therefore, novice dental students were randomly assigned to one of three groups and given the task of drilling a geometrical class 1 cavity. The FB group trained under augmented visual FB conditions, provided by the virtual reality (VR) system (DentSimTM). The no-FB group practised under normal vision conditions, in the absence of augmented FB. A control group performed the test sessions without participating in any training programme. All preparations were evaluated by the VR grading system according to four traditional (outline shape, floor depth, floor smoothness and wall inclination), and two critical, criteria (pulp exposure and damage to adjacent teeth). Performance analyses revealed an overall trend towards significant improvement with training for the experimental groups. The FB group obtained the highest scores. It scored better for floor depth (P < 0.001), whilst the no-FB group was best for floor smoothness (P < 0.005). However, at the retention tests, the FB group demonstrated inferior performance in comparison with the no-FB group. The transfer test on a traditional unit revealed no significant differences between the training groups. Consequently, drilling experience on a VR system under the condition of frequently provided FB and lack of any tutorial input was considered to be not beneficial to learning. The present data are discussed in view of the guidance hypothesis of FB, which refers to the apprentice's dependence on FB. [source] Scanning Kelvin Probe Microscopy on Bulk Heterojunction Polymer BlendsADVANCED FUNCTIONAL MATERIALS, Issue 9 2009Klára Maturová Abstract Here, correlated AFM and scanning Kelvin probe microscopy measurements with sub-100,nm resolution on the phase-separated active layer of polymer-fullerene (MDMO-PPV:PCBM) bulk heterojunction solar cells in the dark and under illumination are described. Using numerical modeling a fully quantitative explanation for the contrast and shifts of the surface potential in dark and light is provided. Under illumination an excess of photogenerated electrons is present in both the donor and acceptor phases. From the time evolution of the surface potential after switching off the light the contributions of free and trapped electrons can be identified. Based on these measurements the relative 3D energy level shifts of the sample are calculated. Moreover, by comparing devices with fine and coarse phase separation, it is found that the inferior performance of the latter devices is, at least partially, due to poor electron transport. [source] Comparative corrosion performance of black oxide, sandblasted, and fine-drawn nitinol wires in potentiodynamic and potentiostatic tests: Effects of chemical etching and electropolishingJOURNAL OF BIOMEDICAL MATERIALS RESEARCH, Issue 2 2004Svetlana Shabalovskaya Abstract The corrosion performance of sandblasted (SB) and smooth fine-drawn (FD) medical-use nitinol wires was compared with the performance of wires with black oxide (BO) formed in air during their manufacture. Potentiodynamic and ASTM F746 potentiostatic tests in a 0.9 % NaCl solution were conducted on wires in their as-received, chemically etched, aged in boiling water, and electropolished states. As-received wires with various surface finishes revealed breakdown potentials in the range from ,100 mV to +500 mV; similar passive current density, 10,6 A/cm2; and a wide hysteresis on the reverse scan, demonstrating strong susceptibility to localized corrosion. Chemically etched wires with original black oxide displayed consistent corrosion performance and surpassed, in corrosion resistance, electropolished wires that showed significantly lower breakdown (400,700 mV) and localized corrosion potentials (,,50 to +113 mV). Sandblasted and fine-drawn wires exhibited rather inconsistent corrosion behavior. In potentiodynamic tests these wires could perform with equal probability either on the level of pretreated BO wires or rather similar to as-received wires. Both SB and FD wires revealed low breakdown potentials in the PS regime. SEM analysis performed before tests indicated that sandblasting was not efficient for the complete removal of the original scaling, and fine drawing aggravated the situation, resulting in a persistent scaling that contributed to the inferior corrosion performance. Inclusions (oxides, carbides, and oxidized carbides) inherited from the bulk and retained on electropolished surfaces are the cause of their inferior performance compared to chemically etched surfaces. In electropolished wires corrosion was initiated around inclusions. © 2004 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 69B: 223,231, 2004 [source] Performance comparisons and attachment: An investigation of competitive responses in close relationshipsPERSONAL RELATIONSHIPS, Issue 3 2005ANTHONY SCINTA Two studies investigated whether affective responses to competitive performance situations are moderated by attachment style. In Study 1, participants (n= 115) imagined their reactions to a superior or inferior performance against their romantic partner or an acquaintance. Results showed that participants low in attachment avoidance, relative to those high in avoidance, indicated more positivity after an inferior performance (empathy effect) to their partners, and this finding held only in domains of high importance to the partner. In Study 2, participants (n= 53) imagined comparisons with their partner or a close friend. Low-avoidance participants, relative to high-avoidance participants, exhibited sympathy and empathy effects in comparisons involving their romantic partner but not those involving a friend. The findings are discussed in terms of one's model of other and perceived self,other separation, which are defined by avoidance but not anxiety. [source] Effects of data incompleteness on the relative performance of parsimony and Bayesian approaches in a supermatrix phylogenetic reconstruction of Mustelidae and Procyonidae (Carnivora)CLADISTICS, Issue 2 2010Mieczyslaw Wolsan Missing data are commonly thought to impede a resolved or accurate reconstruction of phylogenetic relationships, and probabilistic analysis techniques are increasingly viewed as less vulnerable to the negative effects of data incompleteness than parsimony analyses. We test both assumptions empirically by conducting parsimony and Bayesian analyses on an approximately 1.5 × 106 -cell (27 965 characters × 52 species) mustelid,procyonid molecular supermatrix with 62.7% missing entries. Contrary to the first assumption, phylogenetic relationships inferred from our analyses are fully (Bayesian) or almost fully (parsimony) resolved topologically with mostly strong support and also largely in accord with prior molecular estimations of mustelid and procyonid phylogeny derived with parsimony, Bayesian, and other probabilistic analysis techniques from smaller but complete or nearly complete data sets. Contrary to the second assumption, we found no compelling evidence in support of a relationship between the inferior performance of parsimony and taxon incompleteness (i.e. the proportion of missing character data for a taxon), although we found evidence for a connection between the inferior performance of parsimony and character incompleteness (i.e. no overlap in character data between some taxa). The relatively good performance of our analyses may be related to the large number of sampled characters, so that most taxa (even highly incomplete ones) are represented by a sufficient number of characters allowing both approaches to resolve their relationships. © The Willi Hennig Society 2009. [source] | |||||||||||||