Development of adolescent reading comprehension in language 1 and language 2: A longitudinal analysis of constituent components.

This study investigated the relationship between reading comprehension development of 389 adolescents in their dominant language (Language 1 [L1], Dutch) and a foreign language (Language 2 [L2], English). In each consecutive year from Grades 8 through 10, a number of measurements were taken. Students' reading comprehension, their linguistic knowledge (vocabulary and grammar knowledge) and processing efficiency (speed of word recognition and sentence comprehension) in both languages, and their metacognitive knowledge about reading were assessed. The relative strengths of the effects of these components of reading were analyzed to distinguish among 3 hypotheses about the relationship between L1 and L2 reading comprehension: the transfer hypothesis, the threshold hypothesis, and the processing efficiency hypothesis. The transfer hypothesis predicts a strong relationship between L1 and L2 reading comprehension and a strong effect of metacognitive knowledge on L2 reading comprehension, whereas the threshold and processing efficiency hypotheses predict a more important role of language-specific knowledge and processing skills. Results support the transfer hypothesis, although language-specific knowledge and fluency also contribute to L2 reading performance. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Evaluation of three pose estimation algorithms for model-based roentgen stereophotogrammetric analysis

Model-based roentgen stereophotogrammetric analysis (RSA) uses a three-dimensional surface model of an implant in order to estimate accurately the pose of that implant from a stereo pair of roentgen images. The technique is based on minimization of the difference between the actually projected contour of an implant and the virtually projected contour of a model of that same implant. The advantage of model-based RSA over conventional marker-based RSA is that it is not necessary to attach markers to the implant. In this paper, three pose estimation algorithms for model-based RSA are evaluated. The algorithms were assessed on the basis of their sensitivities to noise in the actual contour, to the amount of drop-outs in the actual contour, to the number of points in the actual contour and to shrinkage or expansion of the actual contour. The algorithms that were studied are the iterative inverse perspective matching (IIPM) algorithm, an algorithm based on minimization of the difference (DIF) between the actual contour and the virtual contour, and an algorithm based on minimization of the non-overlapping area (NOA) between the actual and virtual contour. The results of the simulation and phantom experiments show that the NOA algorithm does not fulfil the high accuracy that is necessary for model-based RSA. The IIPM and DIF algorithms are robust to the different distortions, making model-based RSA a possible replacement for marker-based RSA.     

Integrated contour detection and pose estimation for fluoroscopic analysis of knee implants

With fluoroscopic analysis of knee implant kinematics the implant contour must be detected in each image frame, followed by estimation of the implant pose. With a large number of possibly low-quality images, the contour detection is a time-consuming bottleneck. The present paper proposes an automated contour detection method, which is integrated in the pose estimation. In a phantom experiment the automated method was compared with a standard method, which uses manual selection of correct contour parts. Both methods demonstrated comparable precision, with a minor difference in the Y-position (0.08 mm versus 0.06 mm). The precision of each method was so small (below 0.2 mm and 0.3 degrees) that both are sufficiently accurate for clinical research purposes. The efficiency of both methods was assessed on six clinical datasets. With the automated method the observer spent 1.5 min per image, significantly less than 3.9 min with the standard method. A Bland-Altman analysis between the methods demonstrated no discernible trends in the relative femoral poses. The threefold increase in efficiency demonstrates that a pose estimation approach with integrated contour detection is more intuitive than a standard method. It eliminates most of the manual work in fluoroscopic analysis, with sufficient precision for clinical research purposes.     

Detection of pollen grains in multifocal optical microscopy images of air samples

Pollen is a major cause of allergy and monitoring pollen in the air is relevant for diagnostic purposes, development of pollen forecasts, and for biomedical and biological researches. Since counting airborne pollen is a time-consuming task and requires specialized personnel, an automated pollen counting system is desirable. In this article, we present a method for detecting pollen in multifocal optical microscopy images of air samples collected by a Burkard pollen sampler, as a first step in an automated pollen counting procedure. Both color and shape information was used to discriminate pollen grains from other airborne material in the images, such as fungal spores and dirt. A training set of 44 images from successive focal planes (stacks) was used to train the system in recognizing pollen color and for optimization. The performance of the system has been evaluated using a separate set of 17 image stacks containing 65 pollen grains, of which 86% was detected. The obtained precision of 61% can still be increased in the next step of classifying the different pollen in such a counting system. These results show that the detection of pollen is feasible in images from a pollen sampler collecting ambient air. This first step in automated pollen detection may form a reliable basis for an automated pollen counting system. Microsc. Res. Tech., 2009. © 2009 Wiley-Liss, Inc.     

IT capabilities and firm performance: A contingency analysis of the role of industry and IT capability type

Previous empirical studies examining the relationship between IT capability and accounting-based measures of firm performance reported mixed results. We argued that prior work has relied on aggregate overall measures of the firm's IT capability, ignoring the specific type and nature of IT capability; and also has not fully considered important environmental conditions that influence the relationship. Drawing on a resource-based view, we advanced a contingency perspective and proposed that IT capabilities’ impact on firm resources was contingent on the “fit” between the type of IT capability/resource a firm possesses and the demands of the industry in which it competes. Specifically, using publicly available rankings as proxies for two types of IT capabilities (internally and externally focused), we empirically examined the degree to which three industry characteristics (dynamism, munificence, and complexity) influenced the impact of each type of IT capability on measures of financial performance. After controlling for prior performance, we found there was general support for the posited contingency model. The implications of these findings are also discussed.     

Cyclohexane Oxidation Over Size-Uniform Au Nanoparticles (SBA-15 hosted) in a Continuously Stirred Tank Reactor Under Mild Conditions

Cyclohexane oxidation was operated in a continuously stirred tank reactor at system pressures of 0.6–1.0 MPa under an air-like O₂/N₂ atmosphere (rather than pure O₂). Catalytic performance was investigated over Au nanoparticles (size: 3–8 nm) hosted by SBA-15 as well as Au particles (>60 nm) deposited on MCM-41, and high turnover frequencies of desired products were detected over the former. Based on intrinsic activities of representative catalysts, we derived a size-sensitivity feature of cyclohexane oxidation over Au particles.     

Bemessung und Überwachung einer geokunststoffbewehrten Tragschicht auf HSP‐Pfählen

Design and monitoring of a geosynthetic reinforced base‐layer on HSP‐piles. A four‐field fly‐over and the access dam for a double‐track railway line and a bicycle path has been constructed to cross a motorway in a suburb of Rotterdam. The access dam is up to 8.5 m high and was constructed with a slope of 1:2 leading to the preferred small construction width. In spite of the underground conditions with very low shear strength a short‐term traffic initiation as well as low long‐term maintenance cost was demanded. In close collaboration between the contracting authority, the geotechnical consultant CRUX Engineering BV and the construction company Voorbij Funderingstechniek BV a flexible foundations system was developed. Advantages of the chosen system are the possibility top bridge differential settlement, adjust it to the local subsoil conditions and minimise disturbance of the adjacent recreation area. To transfer the self weight and the traffic load into sand layers with higher bearing capacity a combination of Voton HSP‐ piles (high speed piles) and an overlying load distributing geosynthetic stabilised soil layer has been constructed. This innovative combination enables high economic efficiency and an optimised load transfer in the subsoil. A geotechnical monitoring program has been installed to verify that the acting loads on the construction elements are not higher than the allowable loads.     

The dimensions and directionality of trust and their roles in the development of shared business–IS understanding

Prior work suggests that mutual trust is an important antecedent to knowledge transfer and shared understanding between the IS and business units; however, the findings have been based on a conceptualization of trust as a one-dimensional construct. Using a richer dyadic conceptualization and operationalization of trust, we empirically investigated the degree to which the importance of trust varies across two members of a dyadic relationship as well as the different role of distinct facets of trust. Analysis of data collected from two informants (the IS manager and a business-unit counterpart) in a sample of manufacturing firms showed that perceived business-unit trustworthiness was significantly more important in fostering shared business–IS understanding than perceived IS-unit trustworthiness. We attributed this to the inherent power asymmetry that characterizes the relationship between IS and business units. We further hypothesized and found that the importance of the three key dimensions of trust (benevolence, integrity, and competence) depended on the relationship age and organizational position of the IS unit. Our findings show how to manage this critical dyadic relationships more effectively and also where to focus trust-building practices in order to ensure success.     

On the likelihood ratio test in structural equation modeling when parameters are subject to boundary constraints.

The authors show how the use of inequality constraints on parameters in structural equation models may affect the distribution of the likelihood ratio test. Inequality constraints are implicitly used in the testing of commonly applied structural equation models, such as the common factor model, the autoregressive model, and the latent growth curve model, although this is not commonly acknowledged. Such constraints are the result of the null hypothesis in which the parameter value or values are placed on the boundary of the parameter space. For instance, this occurs in testing whether the variance of a growth parameter is significantly different from 0. It is shown that in these cases, the asymptotic distribution of the chi-square difference cannot be treated as that of a central chi-square-distributed random variable with degrees of freedom equal to the number of constraints. The correct distribution for testing 1 or a few parameters at a time is inferred for the 3 structural equation models mentioned above. Subsequently, the authors describe and illustrate the steps that one should take to obtain this distribution. An important message is that using the correct distribution may lead to appreciably greater statistical power. (PsycINFO Database Record (c) 2010 APA, all rights reserved)