bluuebunny/crossref_metadata_2025_split huggingface dataset:
Constructing a minority group identity out of shared rejection: the case of international students
Authors: Schmitt Michael T. , Spears Russell , Branscombe Nyla R. 
Published: January 2003

AbstractWith a sample of international students, we investigated how perceptions of rejection by the host community are related to a sense of identification with other international students. Based on the rejection‐identification model (Branscombe, Schmitt, & Harvey, 1999) we predicted that perceiving prejudice from the host university would be negatively related to psychological well‐being. We expected that group identification with international students would mediate a positive effect of perceived discrimination on self‐esteem, thus suppressing the negative effect of perceiving prejudice on self‐esteem. Consistent with predictions, results supported a model in which identification with international students increased in response to perceiving prejudice and suppressed the costs of perceiving oneself as excluded from the host community. Interestingly, identification with participants' home country was not predicted by perceptions of discrimination. Results are discussed in terms of how minority group members construct group identities in response to the intergroup context. Copyright © 2002 John Wiley & Sons, Ltd.
Immigrant identity of Israeli adolescents from Ethiopia and the former USSR: culture‐specific principles of organization
Authors: Orr Emda , Mana Adi , Mana Yosef 
Published: January 2003

AbstractThe study examines how a sample of 210 high‐school immigrant students (ages 14–15) from Ethiopia and the former USSR socially represent their notion of what klitat aliyah (successful adaptation to Israel) means. Prevalent relevant theories—Berry's model of Acculturation Tendencies (BAT), Social Identity Theory (SIT) and Social Comparison Theory (SCT)—suggest three kinds of patterns by which minority or socially weak groups deal with these kinds of situations. These underlying patterns were tested by a 47‐item questionnaire (with a 4‐point Likert‐like scale), constructed from immigrant narratives regarding their klitat aliyah according to SIT, SCT and BAT categories of adaptation strategies. A Guttman non‐parametric Similarity Structure Analysis (SSA) revealed four‐facet organization of items for both males and females in both sub‐samples. These facets, which reflected social representations of Israeli society, were dubbed: Extended Identity, Rivalry Identity, Secluded Identity and Identity Loss. Results did not confirm the underlying categorization of strategies suggested by SIT and SCT, and partially replicated those suggested by BAT. Copyright © 2002 John Wiley & Sons, Ltd.
Effects of control deprivation on effort expenditure and accuracy performance
Authors: Ric François , Scharnitzky Patrick 
Published: January 2003

AbstractTheoretical positions lead to diverging predictions regarding the impact of control deprivation on subsequent performance. Learned helplessness research suggests that control deprivation impairs subsequent performance. This effect can be attributed either to a decrease in motivation or to a decrease in attentional resources. In contrast, control motivation hypothesis predicts that control deprivation increases careful processing of incoming information, and thus accuracy performance, unless the task is perceived as ego‐threatening. In order to test these diverging predictions against each other, participants were exposed to zero, one, two, four, six or eight unsolvable (vs. solvable) problems and then asked to complete two letter cancellation tasks. This task allowed independent evaluation of effort expenditure (i.e., the number of letters scanned) and accuracy performance (i.e., percentage of letters correctly marked). Overall, the results were consistent with the predictions of the cognitive explanations of learned helplessness deficit as control deprivation at high levels reduced accuracy performance but not effort expenditure. Unexpectedly, effort expenditure was affected by problem solving activity. These results suggest that control deprivation could heighten motivation and, at the same time, deplete cognitive resources. Copyright © 2002 John Wiley & Sons, Ltd.
Integrating commons dilemma findings in a general dynamic model of cooperative behavior in resource crises
Authors: Mosler Hans‐Joachim , Brucks Wernher M. 
Published: January 2003

AbstractThe research on commons dilemmas is characterized by innumerable published findings, each standing relatively isolated from the other. To date there is little integration of the findings under a unified concept. The present contribution aims to integrate already existing findings in a general dynamic model of cooperative behavior in resource crises by means of computer simulation. The model postulates that people base their decisions regarding resource use on both ecological and social information. Whether or not ecological or social information will dominate, however, depends on people's social values, attributions, and their perceptions of the state of the resource. The advantage of the simulation method used is that successful integration of the findings can be shown explicitly, as the simulation then replicates the experimental data. With the model presented here, it is also possible to let variables work together whose interaction has not yet been investigated in real experiments. For instance, the simulation model allows us to hypothesize that people, in dependency upon their resource uncertainty and in dependency upon their attributions, utilize a resource completely differently if the resource is in an optimal or sub‐optimal condition. Copyright © 2002 John Wiley & Sons, Ltd.
Role conflict and academic procrastination: A self‐determination perspective
Authors: Senécal Caroline , Julien Etienne , Guay Frédéric 
Published: January 2003

AbstractThe purpose of the present study was to propose and test a model of role conflict and academic procrastination. This model posits that non‐self‐determined motivations toward school and interpersonal relationships are positively related to role conflict between these two life domains. In turn, role conflict between school and interpersonal relationships is expected to be positively related to academic procrastination. Participants were 292 university students. Results from structural equation modeling supported the model. It thus appears that self‐determination and role conflict are important to foster our understanding of academic procrastination. Theoretical implications of the findings are discussed. Copyright © 2002 John Wiley & Sons, Ltd.
Patterns of damage in igneous and sedimentary rocks under conditions simulating sea‐salt weathering
Authors: Cardell C. , Rivas T. , Mosquera M.J. , Birginie J.M. , Moropoulou A. , Prieto B. , Silva B. , Van Grieken R. 
Published: January 2003

AbstractA saline‐spray artificial ageing test was used to simulate the effects produced in granites and sedimentary rocks (calcarenites, micrites and breccia) under conditions in coastal environments. Three main points were addressed in this study: the durability of the different kinds of rock to salt decay, the resulting weathering forms and the rock properties involved in the weathering processes. For this, mineralogical and textural characterization of each of the different rocks was carried out before and after the test. The soluble salt content at different depths from the exposed surfaces was also determined. Two different weathering mechanisms were observed in the granite and calcareous rocks. Physical processes were involved in the weathering of granite samples, whereas dissolution of calcite was also involved in the deterioration of the calcareous rocks. We also showed that microstructural characteristics (e.g. pore size distribution), play a key role in salt damage, because of their influence on saline solution transport and on the pressures developed within rocks during crystallization. Copyright © 2003 John Wiley & Sons, Ltd.
Organic litter: dominance over stones as a source of interrill flow roughness on low‐gradient desert slopes at Fowlers Gap, arid western NSW, Australia
Authors: Dunkerley David 
Published: January 2003

AbstractThirty‐six runoff plot experiments provide data on flow depths, speeds, and Darcy–Weisbach friction coefficients (f) on bare soil surfaces, and surfaces to which were added sufficient extra plant litter or surface stones to provide projected cover of 5, 10 and 20 per cent. Precision flow depth data were derived with a computer‐controlled gantry and needle gauge for two different discharges for each plot treatment.Taking a fixed flow intensity (Reynolds number, Re = 150) for purposes of comparison shows means of f = 17·7 for bare soil surfaces, f = 11·4 for added stone treatments, and f = 23·8 for added litter treatments. Many individual values of f for stone treatments are lower than for the bare soil surface, but all litter treatments show increases in fcompared to bare soil.The lowering of f in stone treatments relates to the submerged volume that the stones occupied, and the associated concentration of flow onto a smaller part of the plot surface. This leads to locally higher flow intensities and lower frictional drag along threads of flow that the obstacles create.Litter causes higher frictional drag because the particles are smaller, and, for the same cover fraction, are 100 times more numerous and provide 20 times the edge or perimeter length. Along these edges, which in total exceed 2·5 m g−1 (equivalent to 500 m m−2 for a loading of 2 t ha−1), surface tension draws up water from between the litter particles. This reduces flow depth there, and as a consequence of the lower flow intensity, frictional drag rises. Furthermore, no clear passage remains for the establishment of flow threads.These findings apply to shallow interrill flows in which litter is largely immobile. The key new result from these experiments is that under these conditions, a 20 per cent cover of organic litter can generate interrill frictional retardation that exceeds by nearly 41 per cent that of a bare soil surface, and twice that contributed by the same cover fraction of surface stones. Even greater dominance by litter can be anticipated at the many dryland sites where litter covers exceed those tested here. Copyright © 2002 John Wiley & Sons, Ltd.
Prediction of the behaviour of landslide dams using a geomorphological dimensionless index
Authors: Ermini L. , Casagli N. 
Published: January 2003

AbstractLandslide dams are a common phenomenon. They form when a landslide reaches the bottom of a river valley causing a blockage. The first effect of such a dam is the infilling of a lake that inundates the areas upstream, while the possibility of a sudden dam collapse, with a rapid release of the impounded waters, poses a higher flood risk to the downstream areas.The results of the main inventories carried out to date on landslide dams, have been examined to determine criteria for forecasting landslide dam evolution with particular emphasis on the assessment of dam stability. Not all landslides result in the blockage of a river channel. This only occurs with ones that can move a large amount of material with moderate or high‐velocities. In most cases, these landslides are triggered by rainfall events or high magnitude earthquakes. A relationship also exists between the volume of the displaced material and the landslide dam stability.Several authors have proposed that landslide dam behaviour can be forecast by defining various geomorphological indexes, that result from the combination of variables identifying both the dam and the dammed river channel. Further developments of this geomorphological approach are presented in this paper by the definition of a dimensionless blockage index. Starting with an analysis of 84 episodes selected worldwide, it proved to be a useful tool for making accurate predictions concerning the fate of a landslide dam. Copyright © 2002 John Wiley & Sons, Ltd.
Dynamic model for constriction scour caused by large woody debris
Authors: Wallerstein N. P. 
Published: January 2003

AbstractLarge woody debris (LWD) can have a significant impact upon local channel morphology by creating scour pools and zones of reduced shear stress in which sediment is deposited. It is important to predict scour depths associated with LWD, as it is becoming increasingly common for debris to be added into river channels to improve sediment retention and create pools for aquatic habitat. Engineered log‐jams should therefore be designed using factor of safety engineering analysis, which includes estimates of associated scour and deposition rates. However, the rate and total depth of scour associated with LWD have not been modelled comprehensively, with authors resorting to the use of generic local and constriction scour models to predict scour depths. Also, constriction scour models presented, to date, do not calculate the rate of scour development. In this paper a model is presented for predicting the rate and total depth of scour associated with a channel constriction. The model is one‐dimensional and is based upon the sediment continuity equation, the calculation of specific head changes through the constricted reach and also allows for a variable free surface elevation above the bed at the constriction. This model could be applied to any channel constriction problem but here is used to determine scour rates and depths associated with deflector‐type LWD jams. Deflector jams are one category of jam type presented in a debris jam classification scheme, in which jam type is a function of the ratio of average riparian tree height to average channel width. Deflector jams, as the name implies, partially block the flow and therefore act as a channel constriction, which results in constriction scour. Copyright © 2002 John Wiley & Sons, Ltd.
The role of sediment specific gravity and availability on cluster evolution
Authors: Papanicolaou A. N. , Strom K. , Schuyler A. , Talebbeydokhti N. 
Published: January 2003

AbstractThe objective of this experimental study was to account for the role of sediment availability and specific gravity on cluster formation and cluster geometric characteristics (spacing and size). To isolate the effects of sediment availability and specific gravity on cluster evolution, mono‐sized spheres were used to simulate the cluster evolutionary cycle. Overall, twelve experimental runs were carried out in the laboratory flume. Six of these tests were performed by using glass spheres (specific gravity, SG = 2·58) and the other six by employing an equal combination of glass and Teflon spheres (SG = 2·12) of the same diameter to evaluate the role of specific gravity on cluster evolution. The three sediment availability conditions that were investigated here simulated isolated gravel elements, pool–riffle sequences and densely packed gravel‐bed. An advanced image analysis technique was employed to track the evolution of cluster microforms and provide quantitative information about the size and shape of clusters and the number of clusters per unit area. The results of this study showed that: (1) sediment availability affects the architecture and size of cluster microforms; and (2) clusters consisting of mono‐sized sediments start disintegrating at twice the incipient conditions. By performing complementary tests for the isolated gravel elements case, it was found that the evolutionary cycle of individual clusters could be described as follows, in order of increasing stress: no cluster→two particle cluster→comet→triangle→rhomboid→break up. Copyright © 2003 John Wiley & Sons, Ltd.
Recent ventifact development on the central Oregon coast, western USA
Authors: Knight Jasper , Burningham Helene 
Published: January 2003

AbstractThe unusual location of ventifacts, on a boulder‐built jetty at the mouth of the Siuslaw River, Oregon coast, western USA, allows ventifact age and wind abrasion rates to be estimated with some precision. The jetty was built mainly between 1892–1901 and extended throughout the twentieth century. Consideration of historical shoreline position and the history of jetty construction and repair suggests the ventifacts have formed since about 1930.Morphologically the ventifacts are aligned south‐to‐north reflecting winter winds and sediment transport from the adjacent beach. Wind‐parallel grooves and ridges with sharp, sinuous crests are developed on inclined boulder surfaces on top of the jetty and reflect suspended sand transport in wind vortices. Deeply pitted surfaces on steep boulder surfaces nearest the beach reflect impact by saltating sand grains.Based on present wind regimes (1992–2000) from three regional weather stations, southerly winds above the sand transport threshold occur for 21·9–29·6 per cent of the time. Based on estimated depth of loss from boulder surfaces, wind abrasion rates are calculated to be on the order of 0·24–1·63 mm a−1. This is the first well‐constrained field estimate of ventifact age and ventifaction rate from a modern coastal environment. Copyright © 2003 John Wiley & Sons, Ltd.
Interference processes on scouring at bed sills
Authors: Lenzi Mario A. , Marion Andrea , Comiti Francesco 
Published: January 2003

AbstractThe local scouring downstream of bed sills forming a sequence for bed stabilization in steep channels has been investigated in a laboratory flume. The initial bed slopes ranged from 0·078 to 0·148. The bed alluvium was characterised by a non‐uniform grain size distribution. The results show that when the ratio between the critical water depthhcand the sill spacingLrises above a characteristic value the scouring dynamics become heavily affected by the presence of the downstream sill, associated with the onset of a form of “interference” which renders the scouring process less effective. The difference with an “undisturbed” case is demonstrated. Self‐affinity of scour holes is confirmed and the scour length appears to be the reference parameter from which the scour depth might be evaluated. Copyright © 2003 John Wiley & Sons, Ltd.
Solution of the hyperbolic mild‐slope equation using the finite volume method
Authors: Bokaris J. , Anastasiou K. 
Published: January 2003

AbstractA finite volume solver for the 2D depth‐integrated harmonic hyperbolic formulation of the mild‐slope equation for wave propagation is presented and discussed. The solver is implemented on unstructured triangular meshes and the solution methodology is based upon a Godunov‐type second‐order finite volume scheme, whereby the numerical fluxes are computed using Roe's flux function. The eigensystem of the mild‐slope equations is derived and used for the construction of Roe's matrix. A formulation that updates the unknown variables in time implicitly is presented, which produces a more accurate and reliable scheme than hitherto available. Boundary conditions for different types of boundaries are also derived. The agreement of the computed results with analytical results for a range of wave propagation/transformation problems is very good, and the model is found to be virtually paraxiality‐free. Copyright © 2003 John Wiley & Sons, Ltd.
Interface reconstruction with least‐square fit and split Eulerian–Lagrangian advection
Authors: Scardovelli Ruben , Zaleski Stephane 
Published: January 2003

AbstractTwo new volume‐of‐fluid (VOF) reconstruction algorithms, which are based on a least‐square fit technique, are presented. Their performance is tested for several standard shapes and is compared to a few other VOF/PLIC reconstruction techniques, showing in general a better convergence rate. The geometric nature of Lagrangian and Eulerian split advection algorithms is investigated in detail and a new mixed split Eulerian implicit–Lagrangian explicit (EI–LE) scheme is presented. This method conserves the mass to machine error, performs better than split Eulerian and Lagrangian algorithms, and it is only slightly worse than unsplit schemes. However, the combination of the interface reconstruction with the least‐square fit and its advection with the EI–LE scheme appears superior to other existing approaches. Copyright © 2003 John Wiley & Sons, Ltd.
Water quality control by bank placement based on optimal control and finite element method
Authors: Kurahashi T. , Kawahara M. 
Published: January 2003

AbstractThis paper presents a method for quality control by bank placement based on an optimal control theory and the finite element method. The shallow water equation is employed for the analysis of the flow condition and the advection‐diffusion equation is used for the analysis of pollutant concentration. The optimal control theory is utilized to obtain a control value for the objective state value. The shear‐slip mesh update method which is suitable for the rotational problem of body is employed. To solve the optimization problem, the time domain decomposition method is applied as a technique of storage requirements reduction. The Sakawa–Shindo method is employed as a minimization technique. The Crank–Nicolson method is applied to the temporal discretization. A method for optimal control of bank placement has been presented. Copyright © 2003 John Wiley & Sons, Ltd.
A domain decomposition approach to compute wave breaking (wave‐breaking flows)
Authors: Iafrati A. , Campana E. F. 
Published: January 2003

AbstractA heterogeneous domain decomposition approach is followed to simulate the unsteady wavy flow generated by a body moving beneath a free surface. Attention being focused on complex free surface configurations, including wave‐breaking phenomena, a two‐fluid viscous flow model is used in the free surface region to capture the air–water interface (via a level‐set technique), while a potential flow approximation is adopted to describe the flow far from the interface. Two coupling strategies are investigated, differing in the transmission conditions. Both the adopted approaches make use of the inviscid velocity field as boundary condition in the Navier–Stokes solution.For validation purposes, two different two‐dimensional non‐breaking flows are simulated. Domain decomposition results are compared with both fully viscous and fully inviscid results, obtained by solving the corresponding equations in the whole fluid domain, and with available experimental data. Finally, the unsteady evolution of a steep breaking wave is followed and some of the physical phenomena, experimentally observed, are reproduced. Copyright © 2003 John Wiley & Sons, Ltd.
Reconstruction of extended cortical sources for EEG and MEG based on a Monte‐Carlo‐Markov‐chain estimator
Authors: Kincses Wilhelm Emil , Braun Christoph , Kaiser Stefan , Grodd Wolfgang , Ackermann Hermann , Mathiak Klaus 
Published: January 2003

AbstractA new procedure to model extended cortical sources from EEG and MEG recordings based on a probabilistic approach is presented. The method (SPMECS) was implemented within the framework of maximum likelihood estimators. Neuronal activity generating EEG or MEG signals was characterized by the number of sources and their location and extension. Based on the noise distribution of the measured data, source configurations were associated with the according value of the likelihood function. To find the most likely source, i.e., the maximum likelihood estimator, and its level of confidence, a stochastic solver (Metropolis algorithm) was applied. The method presented supports the incorporation of virtually any constraint, e.g., based on physiological and anatomical a priori knowledge. Thus, ambiguity of the ill‐posed inverse problem was reduced considerably by confining sources to the cortical surface extracted from individual MR images. The influence of different levels and types of noise on the outcome was investigated by means of simulations. Somatosensory evoked magnetic fields analyzed by the method presented suggest that larger extended cortical areas are involved in the processing of combined finger stimulation as compared to single finger stimulation. Hum. Brain Mapping 18:100–110, 2003. © 2002 Wiley‐Liss, Inc.