bluuebunny/crossref_metadata_2025 huggingface dataset:
Educational Attainment, Positive Psychological Mediators, and Resources for Health and Vitality in Older Adults
Authors: Murrell Stanley A. , Salsman Nicholas L. , Meeks Suzanne
Published: October 2003

Objectives: To further explain the relationship of education to health by a prospective examination of positive psychological states as mediators. Furthermore, to examine the resources of desirable events, self-esteem, and social support as possible mediators between positive psychological states and subsequent health and vitality. Methods: Four in-home interviews were conducted at 6-month intervals with a probability sample of 1,277 older adults (aged 55 and older); multiple regression was used to estimate mediating effects. Results: Positive states mediated the education relationship to both symptoms and vitality, independent of negative states; the resource measures did not mediate the positive state-health relationship. Discussion: Higher education level appears to increase the likelihood of being serene and happy, and healthy and vital, in later years; positive psychological states appeared to have both a promotion function (for vitality) and protective function (against health symptoms); self-esteem showed promise as a possible mediator of the effects of psychological states on health.
Apoe ε4 as a Predictor of Subjective Quality of Life in a Biracial Older Person Community Sample
Authors: Blazer Dan G. , Fillenbaum Gerda G. , Gold Deborah T. , Burchett Bruce M. , Hays Judith C.
Published: October 2003

Objectives: The ε4 allele of apolipoprotein E (APOE) has been associated with health-related outcomes that may adversely affect quality of life (QOL) in older adults. In the absence of published information, we sought to determine whether the ε4 allele was associated with subjective QOL across 5 parameters in a community sample of older adults. Design: Prospective cohort study. Setting: Community-based sample of older adults in North Carolina (Duke site of the Established Populations for Epidemiologic Studies of the Elderly [Duke EPESE]). Participants: Self-responding genotyped sample members ( n = 1,880) of whom 1,254 provided longitudinal data. Measurements: APOE genotype and five newly constructed, reliable, and valid measures of subjective QOL derived from the Duke EPESE questionnaire. The 5 parameters measured were social, economic, mental and physical health, and functional status. Control variables included age, gender, race (African American or White), education and urban/rural residence. Results: Among those with good baseline QOL, there was no significant association between the ε4 allele and any of the parameters of subjective QOL in longitudinal analyses. In controlled longitudinal analysis, older age women predicted poorer functional status; being African American, and reporting lower education predicted poorer subjective economic well-being; and being African American predicted better self-assessed mental health. Conclusions: This study is among the first to explore the association of the ε4 allele with overall QOL. Considered from a public health perspective, these findings challenge the uncritical assumption that the presence of this susceptibility gene in the population implies an excess burden of poor QOL. The findings do not contradict the previous association of ε4 with Alzheimer's disease (AD) and other conditions. Such conditions continue to merit full attention.
Opening the Black Box of Rationing Care in Later Life
Authors: Simms Mary
Published: October 2003

Research on the rationing of care to older patients in Britain and America typically focuses on acute care here I consider `chronic care'as illustrated by `community care' in Britain. Adopting a critical sociological approach to dependency and to the construction of `later life,'I argue that chronic care users constitute a class, and that clinical need has played a pivotal role in its development. As this reflects the allocative rationing of care I call into question, the claim made by the current British government that need can provide a benchmark of age justice.
Sex and the Grand Old Party
Authors: King David C. , Matland Richard E.
Published: October 2003

We report the results of an experiment involving 820 randomly sampled adults. Half heard about a female Republican candidate for Congress. The other half learned of an otherwise identical male candidate. Democrat and Independent voters were more likely to trust, think qualified, view as a leader, and vote for the female Republican (contrasted with the male Republican). On the other hand, being female led to associations that hurt Republican women within their own party. We augment our experimental results by providing evidence that Republican women have done significantly worse than Democratic women in winning nominations in open-seat congressional districts.
Highlander
Authors: Ebert Olga , Burford Michael L. , Brian Donna Jg
Published: October 2003

This article examines the work of Highlander Research and Education Center, as founded by Myles Horton and others, implemented by staff, and experienced by program participants. Interviews with 8 program participant adult educators and community leaders illustrate Highlander's educational principles and practices, which are briefly compared with transformative educational principles and practices subsequently identified by Freire, with whom Horton ultimately met and compared notes; Mezirow, who later popularized a theory of transformative learning; and others.
Analysis ofmyostatingene structure, expression and function in zebrafish
Authors: Xu Cheng , Wu Gang , Zohar Yonathan , Du Shao-Jun
Published: October 2003

Myostatin is a member of the TGF-β family that functions as a negative regulator of skeletal muscle development and growth in mammals. Recently,Myostatin has also been identified in fish; however, its role in fish muscle development and growth remains unknown. We have reported here the isolation and characterization of myostatin genomic gene from zebrafish and analysis of its expression in zebrafish embryos, larvae and adult skeletal muscles. Our data showed that myostatin was weakly expressed in early stage zebrafish embryos, and strongly expressed in swimming larvae, juvenile and skeletal muscles of adult zebrafish. Transient expression analysis revealed that the 1.2 kb zebrafish myostatin 5′ flanking sequence could direct green fluorescent protein (GFP) expression predominantly in muscle cells, suggesting that the myostatin 5′ flanking sequence contained regulatory elements required for muscle expression. To determine the biological function of Myostatin in fish, we generated a transgenic line that overexpresses the Myostatin prodomain in zebrafish skeletal muscles using a muscle-specific promoter. The Myostatin prodomain could act as a dominant negative and inhibit Myostatin function in skeletal muscles. Transgenic zebrafish expressing the Myostatin prodomain exhibited no significant change in myogenic gene expression and differentiation of slow and fast muscle cells at their embryonic stage. The transgenic fish, however,exhibited an increased number of myofibers in skeletal muscles, but no significant difference in fiber size. Together, these data demonstrate that Myostatin plays an inhibitory role in hyperplastic muscle growth in zebrafish.
Structure and Reactivity of Ziegler–Natta Catalyst Intermediates
Authors: Sobota Piotr
Published: October 2003

This paper provides a survey of our recent research on chemistry that occurs among components of Ziegler–Natta catalysts. Since the amount of information regarding this topic is enormous we have focused on alkoxo compounds, which are attracting more and more attention in polymer industry. In this concept article we discuss recent studies on the inherently very complex catalyst system that involve isolation of various solid polynuclear metal‐containing species, determination of their structures by X‐ray crystallography, and relating their structures to the activity in polymerization. The presented research may be useful in predicting trends for the development of new single‐site catalysts as well as new co‐catalysts.
Transition‐Metal Complexes as Enzyme‐Like Reagents for Protein Cleavage: Complexcis‐[Pt(en)(H2O)2]2+as a New Methionine‐Specific Protease
Authors: Milović Nebojša M. , Dutcǎ Laura‐M. , Kostić Nenad M.
Published: October 2003

Complexcis‐[Pt(en)(H2O)2]2+promotes selective hydrolytic cleavage of two proteins, horse cytochromecand bovineβ‐casein. The cleavage is completed in 24 h under relatively mild conditions, at about pH 2.5, and a temperature as low as 40 °C. The results of HPLC and TSDS PAGE separations, MALDI mass spectrometry, and Edman sequencing showed that cleavage occurred exclusively at the peptide bond involving the C‐terminus of each methionine residue, both such residues in cytochromecand all six such residues inβ‐casein. While having the same selectivity as cyanogen bromide (CNBr), the most common chemical protease,cis‐[Pt(en)(H2O)2]2+has several advantages. It is nonvolatile, easy to handle, and recyclable. Its cleavage is residue‐selective, the rest of the polypeptide backbone remains intact, and the other side chains remain unmodified. It is applied in approximately equimolar amounts with respect to methionine residues, creates free amino and carboxylic groups, and cleaves even the MetPro bond, which is resistant to CNBr and most proteolytic enzymes. Finally the complex also works in the presence of the denaturing reagent sodium dodecyl sulfate. Experiments with the synthetic peptides, AcAla‐Lys‐Tyr‐Gly‐Gly‐Met‐Ala‐Ala‐Arg‐Ala (termed Met‐peptide) and AcVal‐Lys‐Gly‐Gly‐His‐Ala‐Lys‐Tyr‐Gly‐Gly‐Met‐Ala‐Ala‐Arg‐Ala (termed HisMet‐peptide) as substrates, revealed structural and mechanistic features of the proteolytic reactions. We explain why two similar complexes with similar metal ions,cis‐[Pt(en)(H2O)2]2+andcis‐[Pd(en)(H2O)2]2+, differ in selectivity as proteolytic reagents. The selectivity of cleavage is governed by the selectivity of thecis‐[Pt(en)(H2O)2]2+binding to the methionine side chain. The proteolytic activity is governed by the modes of coordination, which control the approach of the anchored PtIIion to the scissile peptide bond. The cleavage occurs with a small, but significant, catalytic turnover of more than 18 after 7 days. The ability ofcis‐[Pt(en)(H2O)2]2+to cleave proteins at relatively few sites, with explicable selectivity and catalytic turnover, bodes well for its use in biochemical practice.
Relaxation of a quantum many‐body system from a correlated initial state. A general and consistent approach
Authors: Semkat D. , Bonitz M. , Kremp D.
Published: October 2003

Various approaches to a theoretical treatment of the dynamics of quantum many‐body systems starting from a correlated initial state are discussed. In particular, we compare the concept of the BBGKY–hierarchy (singletime reduced density operators) and that of nonequilibrium Green's functions (two‐time correlation functions). Conditions for physically meaningful initial correlations are established. (© 2003 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Polygenic inheritance of breast cancer: Implications for design of association studies
Authors: Antoniou Antonis C. , Easton Douglas F.
Published: October 2003

Susceptibility to breast cancer is likely to be the result of susceptibility alleles in many different genes. In particular, one segregation analysis of breast cancer suggested that disease susceptibility in noncarriers of BRCA1/2 mutations may be explicable in terms of a polygenic model, with large numbers of susceptibility polymorphisms acting multiplicatively on risk. We considered the implications for such a model on the design of association studies to detect susceptibility polymorphisms, in particular the efficacy of utilizing cases with a family history of the disease, together with unrelated controls. Relative to a standard case‐control association study with cases unselected for family history, the sample size required to detect a common disease susceptibility allele was typically reduced by more than twofold if cases with an affected first‐degree relative were selected, and by more than fourfold if cases with two affected first‐degree relatives were utilized. The relative efficiency obtained by using familial cases was greater for rarer alleles. Analysis of extended families indicated that the power was most dependent on the immediate (first‐degree) family history. Bilateral cases may offer a similar gain in power to cases with two affected first‐degree relatives. In contrast to the strong effect of family history, varying the ages at diagnosis of the cases across the range of 35–65 years did not strongly affect the power to detect association. These results indicate that association studies based on cases with a strong family history, identified for example through cancer genetics clinics, may be substantially more efficient than population‐based studies. Genet Epidemiol 25: 190–202, 2003. © 2003 Wiley‐Liss, Inc.
Electronic structure and electrical properties of interfaces between metals and π‐conjugated molecular films
Authors: Kahn Antoine , Koch Norbert , Gao Weiying
Published: October 2003

The field of organic thin films and devices is progressing at an extremely rapid pace. Organic–metal and organic–organic interfaces play crucial roles in charge injection into, and transport through, these devices. Their electronic structure, chemical properties, and electrical behavior must be fully characterized and understood if the engineering and control of organic devices are to reach the levels obtained for inorganic semiconductor devices. This article provides an extensive, although admittedly nonexhaustive, review of experimental work done in our group on the electronic structure and electrical properties of interfaces between films of π‐conjugated molecular films and metals. It introduces several mechanisms currently believed to affect the formation of metal–organic interface barriers. © 2003 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 41: 2529–2548, 2003
Electronic study of FeTi, CoTi, and NiTi alloys: bulk, surfaces, and interfaces
Authors: Kellou A. , Nabi Z. , Tadjer A. , Amrane N. , Fenineche N. , Aourag H.
Published: October 2003

The full‐potential linearized augmented plane waves (FP‐LAPW) method within the generalized gradient approximation (GGA) is applied to determine the electronic properties of the equiatomic alloys B2‐MTi (M = Fe, Co, Ni). Detailed analysis is devoted to the NiTi austenic, premartensic, and martensic phases. The martensic transformation (MT) occurs from the austenic B2 (CsCl structure) to the monoclinic B19' phase upon cooling. Spin‐polarized slab calculations are carried out to study the FeTi(001), CoTi(001), and NiTi(001) surfaces and the FeTi/CoTi, FeTi/NiTi, and CoTi/NiTi interfaces. The stability mechanism of the interface is related to the calculated ideal work of adhesion. The corresponding electronic structure and local magnetic moments of the surface, sub‐surface, and central layers are also given. (© 2003 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Context rules
Authors: Bressler Steven L.
Published: October 2003

It is proposed that cortical activity is normally coordinated across synaptically connected areas and that this coordination supports cognitive coherence relations. This view is consistent with the NMDA- hypoactivity hypothesis of the target article in regarding disorganization symptoms in schizophrenia as arising from disruption of normal interareal coordination. This disruption may produce abnormal contextual effects in the cortex that lead to anomalous cognitive coherence relations.
Olive green or chestnut brown?
Authors: Kuehni Rolf G.
Published: October 2003

Reflectance and spectral power functions are poor predictors of color experiences. Only in completely relativized conditions (single observer, non-metameric set of stimuli, and single set of viewing conditions) is the relationship close. Variation in reflectance of Munsell chips experienced by color-normal observers as having a unique green hue encompasses approximately sixty percent of the complete range of hues falling under the category “green”; and in recent determinations of unique hues, ranges of yellow and green as well as green and blue unique hues overlap.
NMDA synapses can bias competition between object representations and mediate attentional selection
Authors: Raffone Antonino , Murre Jaap M. J. , Wolters Gezinus
Published: October 2003

Phillips & Silverstein emphasize the gain-control properties of NMDA synapses in cognitive coordination. We endorse their view and suggest that NMDA synapses play a crucial role in biased attentional competition and (visual) working memory. Our simulations show that NMDA synapses can control the storage rate of visual objects. We discuss specific predictions of our model about cognitive effects of NMDA-antagonists and schizophrenia.
Confusion of sensations and their physical correlates
Authors: Warren Richard M.
Published: October 2003

The authors favor a “color realism” theory that considers colors to be physical properties residing in objects that reflect, emit, or transmit light. It is opposed to the theory that colors are sensations or visual experiences. This commentary suggests that both theories are correct, and that context usually indicates which of these dual aspects is being considered.
Simple stochastic birth and death models of genome evolution: was there enough time for us to evolve?
Authors: Karev Georgy P. , Wolf Yuri I. , Koonin Eugene V.
Published: October 2003

Motivation: The distributions of many genome-associated quantities, including the membership of paralogous gene families can be approximated with power laws. We are interested in developing mathematical models of genome evolution that adequately account for the shape of these distributions and describe the evolutionary dynamics of their formation.

Results: We show that simple stochastic models of genome evolution lead to power-law asymptotics of protein domain family size distribution. These models, called Birth, Death and Innovation Models (BDIM), represent a special class of balanced birth-and-death processes, in which domain duplication and deletion rates are asymptotically equal up to the second order. The simplest, linear BDIM shows an excellent fit to the observed distributions of domain family size in diverse prokaryotic and eukaryotic genomes. However, the stochastic version of the linear BDIM explored here predicts that the actual size of large paralogous families is reached on an unrealistically long timescale. We show that introduction of non-linearity, which might be interpreted as interaction of a particular order between individual family members, allows the model to achieve genome evolution rates that are much better compatible with the current estimates of the rates of individual duplication/loss events.
Effect of Spontaneous Emission Noise and Modulation on Semiconductor Lasers Near Threshold with Optical Feedback
Authors: Lam Wing-Shun , Guzdar Parvez N. , Roy Rajarshi
Published: October 2003

The dynamical behavior of power dropouts in a semiconductor laser with optical feedback, pumped near threshold current, is strongly influenced by quantum noise. This is clearly demonstrated by experiments with modulations on the pumping current or the feedback strength. For the cases without modulation and with only current modulation, the dropouts occur randomly. However the feedback strength modulation locks the dropout events periodically. By numerically modeling these three cases using the Lang–Kobayashi equations with a stochastic term to take into account spontaneous emission noise, it is shown that the observed behavior of the dropouts can be readily reproduced for all three cases. Noise plays a signifcant role in explaining the observed dropout events. A simple explanation of the observed dropout phenomenon is presented, based on the adiabatic motion of the ellipse formed by the steady state solutions of the rate equations due to slow time modulations of the injection current or the feedback strength.
Associative Dynamics and Its Control of Chaotic Neural Network
Authors: Cao Zhitong , Chen Hongping , He Guoguang
Published: October 2003

In this paper, the Nagumo-Sato model is used to construct a chaotic neural network (CNN). Each reference sample is stored in the chaos attractor that is formed by the associative dynamics. When the inputs sometimes deviate obviously from its original attractive region and the correct association is not realized by itself, the feedback pinning is use to control the associative dynamics. The lost original memory will be retrieved quickly considering the fact that the CNN is a spatiotemporal system. The simulation experiments of both the associative dynamics and the retrieval process are done for the faults of broken rotor bars of an induction motor. The results show that the feedback pinning control is a simple and effective control method to the CNN.
Homology of Vertex and Edge Shift Matrices in Symbolic Dynamics and Entropy Invariants
Authors: Cao Ke-Fei , Peng Shou-Li
Published: October 2003

By using the homological notion, we analyze the vertex and edge shift matrices in symbolic dynamics. The former is the mathematical basis of the general star product which is transformed into a star direct product of vertex shift matrices, the latter a basis of the calculation of topological entropy. We show that in a general case the first entropy invariant holds, but the second one is broken.
On the Diffusion Along Resonant Lines in Continuous and Discrete Dynamical Systems
Authors: Froeschlé Claude , Lega Elena
Published: October 2003

We detect and measure diffusion along resonances in a discrete symplectic map for different values of the coupling parameter. Qualitatively and quantitatively the results are very similar to those obtained for a quasi-integrable Hamiltonian system, i.e. in agreement with Nekhoroshev predictions, although the discrete mapping does not fulfill completely, a priori, the conditions of the Nekhoroshev theorem.
A Symmetric Galerkin Formulation of the Boundary Element Method for Acoustic Radiation and Scattering
Authors: Chen Z. S. , Hofstetter G. , Mang H. A.
Published: October 2003

A symmetric Galerkin formulation of the Boundary Element Method for acoustic radiation and scattering is presented. The basic integral equations for radiation and scattering of sound are derived for structures, which may consist of a combination of a three-dimensional closed part and thin-walled parts. For the numerical solution of these integral equations a Galerkin-type numerical solution scheme is proposed. The evaluation of the weakly-singular and the hypersingular integrals, occurring in this formulation, is addressed briefly. An improved CHIEF-method is employed in order to prevent the singularity of the coefficient matrix of the algebraic system of equations at so-called irregular frequencies. Subsequently, an algorithm for the automatic determination of the number of nodal unknowns at intersections of thin-walled parts of a structure, or of thin-walled parts and the three-dimensional closed part of a structure, is described. The numerical study contains comparisons of analytical solutions for simple academic examples with the numerical results. In addition, a comparison of measured and computed results is presented for a structure, consisting of both a three-dimensional closed part and a thin-walled part.
A Small Axisymmetric Obstacle in the Presence of an Underwater Point-Source Field
Authors: Charalambopoulos A. , Dassios G. , Ergatis P.
Published: October 2003

A small, acoustically hard and axisymmetric object is placed in a deep homogeneous sea environment with a hard plane bottom. The free surface of the sea is assumed to be soft. The source and the receiver are placed on the same vertical line, far away from the object. Given the positions of the source and the receiver, two problems are solved: the determination of the pressure field at the receiver from the position and the shape of the object, and the determination of the position and the shape of the object from the pressure field at the receiver. The special case of smooth objects generated by the rotation of differentiable curves is studied. We provide results for the case of a floating object and for the case of an object or a boss at the bottom of the sea.
Generalized Replicator Dynamics as a Model of Specialization and Diversity in Societies
Authors: Borkar Vivek S. , Jain Sanjay , Rangarajan Govindan
Published: October 2003

We consider a generalization of replicator dynamics as a non-cooperative evolutionary game-theoretic model of a community of N agents. All agents update their individual mixed strategy profiles to increase their total payoff from the rest of the community. The properties of attractors in this dynamics are studied. Evidence is presented that under certain conditions the typical attractors of the system are corners of state space where each agent has specialized to a pure strategy, and/or the community exhibits diversity, i.e., all strategies are represented in the final states. The model suggests that new pure strategies whose payoff matrix elements satisfy suitable inequalities with respect to the existing ones can destabilize existing attractors if N is sufficiently large, and be regarded as innovations that enhance the diversity of the community.
Regulated Criticality in the Brain?
Authors: Bienenstock Elie , Lehmann Daniel
Published: October 2003

We propose that a regulation mechanism based on Hebbian covariance plasticity may cause the brain to operate near criticality. We analyze the effect of such a regulation on the dynamics of a network with excitatory and inhibitory neurons and uniform connectivity within and across the two populations. We show that, under broad conditions, the system converges to a critcal state lying at the common boundary of three regions in parameter space; these correspond to three modes of behavior: high activity, low activity, oscillation.
Reproducing color images with embedded metallic patterns
Authors: Hersch Roger D. , Collaud Fabien , Emmel Patrick
Published: October 2003

By combining a metallic ink and standard inks, one may create printed images having a dynamic appearance: an image viewed under specular reflection may be considerably different from the same image viewed under non-specular reflection. Patterns which are either dark or hidden become highlighted under specular reflection, yielding interesting visual effects. To create such images, one needs to be able to reproduce at non-specular reflection angles the same colors, by standard inks alone or in combination with a metallic ink. Accurate color prediction models need to be established which model the underlying physical phenomena in a consistent manner. To meet this challenge, we propose two models, one for predicting the reflection spectra of standard inks on coated paper and one for predicting the reflection spectra of a combination of standard inks and a metallic ink. They are enhancements of the classical Clapper-Yule model which models optical dot gain of halftone prints by taking into account lateral scattering within the paper bulk and multiple internal reflections. The models we propose also take into account physical dot gain and ink spreading for standard inks as well as the low reflectance of metallic inks at non-specular reflection angles and the poor adherence of standard inks printed on top of a metallic ink (trapping effect). These models open the way towards color separation of images to be reproduced by combining a metallic ink and standard inks. Several designs printed on an offset press demonstrate their applicability and their benefits for high-end design and security applications.
Discrete multiscale vector field decomposition
Authors: Tong Yiying , Lombeyda Santiago , Hirani Anil N. , Desbrun Mathieu
Published: October 2003

While 2D and 3D vector fields are ubiquitous in computational sciences, their use in graphics is often limited to regular grids, where computations are easily handled through finite-difference methods. In this paper, we propose a set of simple and accurate tools for the analysis of 3D discrete vector fields on arbitrary tetrahedral grids. We introduce a variational, multiscale decomposition of vector fields into three intuitive components: a divergence-free part, a curl-free part, and a harmonic part. We show how our discrete approach matches its well-known smooth analog, called the Helmotz-Hodge decomposition, and that the resulting computational tools have very intuitive geometric interpretation. We demonstrate the versatility of these tools in a series of applications, ranging from data visualization to fluid and deformable object simulation.
T-splines and T-NURCCs
Authors: Sederberg Thomas W. , Zheng Jianmin , Bakenov Almaz , Nasri Ahmad
Published: October 2003

This paper presents a generalization of non-uniform B-spline surfaces called T-splines. T-spline control grids permit T-junctions, so lines of control points need not traverse the entire control grid. T-splines support many valuable operations within a consistent framework, such as local refinement, and the merging of several B-spline surfaces that have different knot vectors into a single gap-free model. The paper focuses on T-splines of degree three, which are
C
2
(in the absence of multiple knots). T-NURCCs (Non-Uniform Rational Catmull-Clark Surfaces with T-junctions) are a superset of both T-splines and Catmull-Clark surfaces. Thus, a modeling program for T-NURCCs can handle any NURBS or Catmull-Clark model as special cases. T-NURCCs enable true local refinement of a Catmull-Clark-type control grid: individual control points can be inserted only where they are needed to provide additional control, or to create a smoother tessellation, and such insertions do not alter the limit surface. T-NURCCs use stationary refinement rules and are
C
2
except at extraordinary points and features.
Anisotropic polygonal remeshing
Authors: Alliez Pierre , Cohen-Steiner David , Devillers Olivier , Lévy Bruno , Desbrun Mathieu
Published: October 2003

In this paper, we propose a novel polygonal remeshing technique that exploits a key aspect of surfaces: the intrinsic
anisotropy
of natural or man-made geometry. In particular, we use curvature directions to drive the remeshing process, mimicking the lines that artists themselves would use when creating 3D models from scratch. After extracting and smoothing the curvature tensor field of an input genus-0 surface patch, lines of minimum and maximum curvatures are used to determine appropriate edges for the remeshed version in anisotropic regions, while spherical regions are simply point sampled since there is no natural direction of symmetry locally. As a result our technique generates polygon meshes mainly composed of quads in anisotropic regions, and of triangles in spherical regions. Our approach provides the flexibility to produce meshes ranging from isotropic to anisotropic, from coarse to dense, and from uniform to curvature adapted.
Boom chameleon
Authors: Tsang Michael , Fitzmzurice George W. , Kurtenbach Gordon , Khan Azam , Buxton Bill
Published: October 2003

We review the Boom Chameleon, a novel input/output device consisting of a flat-panel display mounted on a tracked mechanical armature. The display acts as a physical window into 3D virtual environments, through which a one-to-one mapping between real and virtual space is preserved. The Boom Chameleon is further augmented with a touch-screen and a microphone/speaker combination. We created a 3D annotation application that exploits this unique configuration in order to simultaneously capture viewpoint, voice and gesture information. Results of an informal user study show that the Boom Chameleon annotation facilities have the potential to be an effective, and intuitive system for reviewing 3D designs.
Modeling and generating multivariate time-series input processes using a vector autoregressive technique
Authors: Biller Bahar , Nelson Barry L.
Published: October 2003

We present a model for representing stationary multivariate time-series input processes with marginal distributions from the Johnson translation system and an autocorrelation structure specified through some finite lag. We then describe how to generate data accurately to drive computer simulations. The central idea is to transform a Gaussian vector autoregressive process into the desired multivariate time-series input process that we presume as having a VARTA (Vector-Autoregressive-To-Anything) distribution. We manipulate the autocorrelation structure of the Gaussian vector autoregressive process so that we achieve the desired autocorrelation structure for the simulation input process. We call this thecorrelation-matching problemand solve it by an algorithm that incorporates a numerical-search procedure and a numerical-integration technique. An illustrative example is included.
Dynamic structure multiparadigm modeling and simulation
Authors: Barros Fernando J.
Published: October 2003

This article presents the Heterogeneous Flow System Specification (HFSS), a formalism aimed to represent hierarchical and modular hybrid flow systems with dynamic structure. The concept of hybrid flow systems provides a generalization of the conventional concept of hybrid system and it can represent a whole plethora of systems, namely: discrete event systems, multicomponent and multirate numerical methods, multirate and multicomponent sampling systems, event locators and time-varying systems. The ability to join all these types of models makes HFSS an excellent framework for merging components built in different paradigms. We present several examples of model definition in the HFSS formalism and we also exploit the ability of the HFSS formalism to represent mutirate numerical integrators.
Are you looking at me? Eye contact and desktop video conferencing
Authors: Grayson David M. , Monk Andrew F.
Published: October 2003

Mutual gaze is an important conversational resource, but is difficult to provide using conventional video conferencing equipment due to the disparity between the position of the camera and the position of the eyes on the screen. Various elaborate inventions have been proposed to get around this problem but none have found wide use. The alternative explored here is that these expensive alternatives may be unnecessary. Users of conventional desktop video equipment may, under the right conditions, be able to learn to interpret what is at first sight inappropriate apparent gaze direction as signalling that the other person is "looking at me."Data are presented from two experiments where an estimator judges where a gazer is looking. The gazer may be looking either at the desktop video image of the estimator or some point to the side. Experiment 1 compared two image sizes and two camera positions. While the size of the image (352 × 288 pixels versus 176 × 144) had no significant effect on participants' ability to judge where the gazer was looking, horizontally offsetting the position of the camera inhibited performance. Experiment 2 examined the effect of reducing the image size further. The smallest image size (88 × 72 pixels) resulted in poorer performance than the intermediate (176 × 144). The results show that it is possible for users of low cost desktop video conferencing to learn to interpret gaze direction to a very high degree of accuracy if the equipment is configured optimally. The practical and theoretical implications of these results are discussed.
Removing permissions in the flexible authorization framework
Authors: Wijesekera Duminda , Jajodia Sushil , Parisi-Presicce Francesco , Hagström Åsa
Published: October 2003

The Flexible Authorization Framework (FAF) defined by Jajodia et al. [2001] provides a policy-neutral framework for specifying access control policies that is expressive enough to specify many known access control policies. Although the original formulation of FAF indicated how rules could be added to or deleted from a FAF specification, it did not address the removal of access permissions from users. We present two options for removing permissions in FAF and provide details on the option which is representation independent.
A formal approach for designing CORBA-based applications
Authors: Coen-Porisini Alberto , Pradella Matteo , Rossi Matteo , Mandrioli Dino
Published: October 2003

The design of distributed applications in a CORBA-based environment can be carried out by means of an incremental approach, which starts from the specification and leads to the high-level architectural design. This article discusses a methodology to transform a formal specification written in TRIO into a high-level design document written in an extension of TRIO, named TRIO/CORBA (TC). The TC language is suited to formally describe the high-level architecture of a CORBA-based application. As a result, designers are offered high-level concepts that precisely define the architectural elements of an application. Furthermore, TC offers mechanisms to extend its base semantics, and can be adapted to future developments and enhancements in the CORBA standard. The methodology and the associated language are presented through a case study derived from a real Supervision and Control System.
Geometric surface processing via normal maps
Authors: Tasdizen Tolga , Whitaker Ross , Burchard Paul , Osher Stanley
Published: October 2003

We propose that the generalization of signal and image processing to surfaces entails filtering the normals of the surface, rather than filtering the positions of points on a mesh. Using a variational strategy, penalty functions on the surface geometry can be formulated as penalty functions on the surface normals, which are computed using geometry-based shape metrics and minimized using fourth-order gradient descent partial differential equations (PDEs). In this paper, we introduce a two-step approach to implementing geometric processing tools for surfaces: (i) operating on the normal map of a surface, and (ii) manipulating the surface to fit the processed normals. Iterating this two-step process, we efficiently can implement geometric fourth-order flows by solving a set of coupled second-order PDEs. The computational approach uses level set surface models; therefore, the processing does not depend on any underlying parameterization. This paper will demonstrate that the proposed strategy provides for a wide range of surface processing operations, including edge-preserving smoothing and high-boost filtering. Furthermore, the generality of the implementation makes it appropriate for very complex surface models, for example, those constructed directly from measured data.
Call graph prefetching for database applications
Authors: Annavaram Murali , Patel Jignesh M. , Davidson Edward S.
Published: October 2003

With the continuing technological trend of ever cheaper and larger memory, most data sets in database servers will soon be able to reside in main memory. In this configuration, the performance bottleneck is likely to be the gap between the processing speed of the CPU and the memory access latency. Previous work has shown that database applications have large instruction and data footprints and hence do not use processor caches effectively. In this paper, we propose Call Graph Prefetching (CGP), an N instruction prefetching technique that analyzes the call graph of a database system and prefetches instructions from the function that is deemed likely to be called next. CGP capitalizes on the highly predictable function call sequences that are typical of database systems. CGP can be implemented either in software or in hardware. The software-based CGP (
CGP_S
) uses profile information to build a call graph, and uses the predictable call sequences in the call graph to determine which function to prefetch next. The hardware-based CGP(
CGP_H
) uses a hardware table, called the Call Graph History Cache (CGHC), to dynamically store sequences of functions invoked during program execution, and uses that stored history when choosing which functions to prefetch.We evaluate the performance of CGP on sets of Wisconsin and TPC-H queries, as well as on CPU-2000 benchmarks. For most CPU-2000 applications the number of instruction cache (I-cache) misses were very few even without any prefetching, obviating the need for CGP. On the other hand, the database workloads do suffer a significant number of I-cache misses;
CGP_S
improves their performance by 23% and
CGP_H
by 26% over a baseline system that has already been highly tuned for efficient I-cache usage by using the OM tool. CGP, with or without OM, reduces the I-cache miss stall time by about 50% relative to O5+OM, taking us about half way from an already highly tuned baseline system toward perfect I-cache performance.
The Politics of Racial Reparations
Authors: Henry Charles P.
Published: October 2003

This article seeks to establish the necessary theoretical and political grounds for reparations. It is the aim of the article to examine the various ways in which scholars and politicians have framed the historical debate on reparations and then to introduce a possible approach that would take into consideration something more than slavery. In fact, the article concludes that slavery was just one aspect of the dispossession of the African in the United States. Thus, it will be necessary to consider the entire history of African Americans as constituting a warrant for reparations.
Using Focus Groups to Develop Culturally Relevant Instruments
Authors: Willgerodt Mayumi Anne
Published: October 2003

Recent criticism has focused on the validity of instruments used in research with immigrant populations. Conventional instrument development or validation techniques may not be adequate to determine whether an instrument is appropriate for use with populations who differ from those with whom the instrument was originally developed. This article discusses the value of using focus group methodology to develop instruments for use with immigrant populations using the example of an intergenerational conflict tool for multigenerational Chinese immigrant families. Involving community members through focus groups is an important component of instrument development that is often neglected by researchers. This process was critical to developing a culturally appropriate instrument that accurately reflected the community's life experiences. Strategies for conducting meaningful and successful focus groups with Chinese immigrants are provided. Advantages and disadvantages of using focus groups are also discussed.
Transforming Vulnerability
Authors: Jones Patricia S. , Zhang Xinwei Esther , Meleis Afaf I.
Published: October 2003

Asian American immigrant women engaged in filial caregiving are at special risk for health problems due to complex contextual factors related to immigration, cultural traditions, and role transition. This study examines the experience of two groups of immigrant Asian American women who are caring for older parents. A total of 41 women (22 Chinese American and 19 Filipino American) were interviewed in a study based on Strauss and Corbin's grounded theory methodology. The women were determined to be loyal to their traditional culture, which included strong filial values, while adapting to a new culture. Through the struggle of meeting role expectations and coping with paradox, the women mobilized personal and family resources to trans-form vulnerability into strength and well-being.
Addressing the Service Linkage Problem
Authors: Ogle Richard L. , Baer John S.
Published: October 2003

Two personalized substance abuse assessment and feedback interventions were tested for effectiveness in engaging female domestic violence shelter residents in sub-stance abuse treatment. One hundred forty-seven residents were assessed for quantity and frequency of substance use, negative consequences due to use, motivation to change substance use behavior, and psychopathological symptoms related to sub-stance abuse. Assessment identified (33) 22% of participants as heavy substance users. Twenty of the 33 heavy-using residents received one of two personalized sub-stance use feedback interventions: face-to-face feedback or written feedback placed in shelter mailboxes. Treatment engagement was defined as attending at least one substance abuse treatment session within 30 days after the intervention. Results showed a significant difference in treatment engagement rates in favor of the face-to-face feedback group (60% vs. 0%). The results provide preliminary data suggesting that substance abuse assessment can be effectively accomplished in the shelter environment and that the face-to-face feedback procedure may be an effective intervention to bridge the service linkage problem between domestic violence services and substance abuse treatment.
The Toll of Domestic Violence
Authors: Sharhabani-Arzy Ronit , Amir Marianne , Kotler Moshe , Liran Ruth
Published: October 2003

The study examines the prevalence of posttraumatic stress disorder (PTSD) among battered women in Israel and the associated psychological distress. This study inquires into the psychological reactions of battered women in comparison to women who experienced other types of traumas by examining PTSD rates and intensity of psychiatric symptoms and suicide risk. The research sample was comprised of 91 battered women, and the control group was comprised of 82 women who underwent other traumas excluding interpersonal traumas. The participants were administered questionnaires relating to type and intensity of domestic violence, PTSD symptoms, intensity of psychiatric symptoms, and suicide risk. The results showed that 51.6% of the battered women had full PTSD. Battered women exhibited significantly higher levels of psychiatric symptoms than the control group. Battered women who were diagnosed with PTSD scored significantly higher than battered women without PTSD on the same indicator. The findings emphasize the toll and severity of domestic trauma.
E-Democracy
Authors: Kampen Jarl K. , Snijkers Kris
Published: October 2003

In this article, the authors examine the possibilities of information communication technology and e-government to enhance democracy. The authors summarize the known problems of representative democracy and direct democracy and inquire whether e-government potentially can offer solutions to these problems. The authors conclude that a lot of problems in both representative and direct democracies remain unsolved and that e-government even can create new problems.
Neoinstitutionalism and E-Government
Authors: Yang Kaifeng
Published: October 2003

This article addresses the evolution and implementation of e-government with a neoinstitutional perspective. It starts with a critique on Jane Fountain's technology enactment framework in that the framework fails to show how elected officials, public administrators, and citizens can facilitate e-government toward better democratic governance. This problem reflects the immaturity and ambiguity of neo-institutionalism in accounting for institutional change. The author argues that a balance between agent and institution, between strategic choice and institutional constraint should be maintained in analyzing the evolution of e-government as a long-term institutional change. This balanced approach would give public administration a more optimistic future of e-government.
Beyond the Digital Divide in Canadian Schools
Authors: Looker E. Dianne , Thiessen Victor
Published: October 2003

This article provides a descriptive analysis of issues related to the access and use of information and communication technology (ICT) among Canadian youth. In particular, it examines the extent to which inequities in the use of and access to ICT exist among Canadian high school students based on gender, socioeconomic status, and rural-urban location. The analyses suggest that there is a digital divide for Canadian youth in access to and experience with ICT. Rural youth are less likely to have access to computers in the home; however, frequency of use and perceived competency levels are not compromised because they make greater use of computers at school. Female youth and those from families with low levels of parental education are also less likely to have access to computers in their homes; they tend to access computers less frequently and report lower levels of computer skills competency.