bluuebunny/crossref_metadata_2025_split huggingface dataset:
A framework for quad/triangle subdivision surface fitting: Application to mechanical objects
Authors: Lavoué Guillaume , Dupont Florent , Baskurt Atilla 
Published: March 2007

Abstract In this paper we present a new framework for subdivision surface approximation of three‐dimensional models represented by polygonal meshes. Our approach, particularly suited for mechanical or Computer Aided Design (CAD) parts, produces a mixed quadrangle‐triangle control mesh, optimized in terms of face and vertex numbers while remaining independent of the connectivity of the input mesh. Our algorithm begins with a decomposition of the object into surface patches. The main idea is to approximate the region boundaries first and then the interior data. Thus, for each patch, a first step approximates the boundaries with subdivision curves (associated with control polygons) and creates an initial subdivision surface by linking the boundary control points with respect to the lines of curvature of the target surface. Then, a second step optimizes the initial subdivision surface by iteratively moving control points and enriching regions according to the error distribution. The final control mesh defining the whole model is then created assembling every local subdivision control meshes. This control polyhedron is much more compact than the original mesh and visually represents the same shape after several subdivision steps, hence it is particularly suitable for compression and visualization tasks. Experiments conducted on several mechanical models have proven the coherency and the efficiency of our algorithm, compared with existing methods.
Effective Derivation of Similarity Transformations for Implicit Laplacian Mesh Editing
Authors: Fu Hongbo , Kin‐Chung Au Oscar , Tai Chiew‐Lan 
Published: March 2007

Abstract Laplacian coordinates as a local shape descriptor have been employed in mesh editing. As they are encoded in the global coordinate system, they need to be transformed locally to reflect the changed local features of the deformed surface. We present a novel implicit Laplacian editing framework which is linear and effectively captures local rotation information during editing. Directly representing rotation with respect to vertex positions in 3D space leads to a nonlinear system. Instead, we first compute the affine transformations implicitly defined for all the Laplacian coordinates by solving a large sparse linear system, and then extract the rotation and uniform scaling information from each solved affine transformation. Unlike existing differential‐based mesh editing techniques, our method produces visually pleasing deformation results under large angle rotations or big‐scale translations of handles. Additionally, to demonstrate the advantage of our editing framework, we introduce a new intuitive editing technique, called configuration‐independent merging, which produces the same merging result independent of the relative position, orientation, scale of input meshes.
A Survey of Haptic Rendering Techniques
Authors: Laycock S.D. , Day A.M. 
Published: March 2007

AbstractComputer Graphics technologies have developed considerably over the past decades. Realistic virtual environments can be produced incorporating complex geometry for graphical objects and utilising hardware acceleration for per pixel effects. To enhance these environments, in terms of the immersive experience perceived by users, the human's sense of touch, or haptic system, can be exploited. To this end haptic feedback devices capable of exerting forces on the user are incorporated. The process of determining a reaction force for a given position of the haptic device is known as haptic rendering. For over a decade users have been able to interact with a virtual environment with a haptic device. This paper focuses on the haptic rendering algorithms which have been developed to compute forces as users manipulate the haptic device in the virtual environment.
Modeling and Rendering of Heterogeneous Granular Materials: Granite Application
Authors: Soulié Romain , Mérillou Stéphane , Terraz Olivier , Ghazanfarpour Djamchid 
Published: March 2007

AbstractLight‐matter interactions is one of the most important factors of realistic rendering. While a lot of work has already been performed in the light transport and simulation area, we believe that “virtual materials” have not yet been studied enough to achieve a high degree of realism. Some good models exist in order to take into account homogeneous materials. However, there are only a few studies of heterogeneous granular materials. In this paper, we propose a method based on mimicking natural phenomena to take into account these materials. Our study focuses on granite, which can be considered as a heterogeneous agglomerate of individually homogeneous grains. First we present a nucleation/growth process inspired technique giving a full 3D model of granite. Then, we use a rendering process taking into account each material component and subsurface scattering in a simple way.
Response-Adaptive Randomization for Survival Trials: The Parametric Approach
Authors: Zhang Lanju , Rosenberger William F. 
Published: March 2007

Summary
Few references deal with response-adaptive randomization procedures for survival outcomes and those that do either dichotomize the outcomes or use a non-parametric approach. In this paper, the optimal allocation approach and a parametric response-adaptive randomization procedure are used under exponential and Weibull distributions. The optimal allocation proportions are derived for both distributions and the doubly adaptive biased coin design is applied to target the optimal allocations. The asymptotic variance of the procedure is obtained for the exponential distribution. The effect of intrinsic delay of survival outcomes is treated. These findings are based on rigorous theory but are also verified by simulation. It is shown that using a doubly adaptive biased coin design to target the optimal allocation proportion results in more patients being randomized to the better performing treatment without loss of power. We illustrate our procedure by redesigning a clinical trial.
Experimental Designs for Binary Data in Switching Measurements on Superconducting Josephson Junctions
Authors: Karvanen Juha , Vartiainen Juha J. , Timofeev Andrey , Pekola Jukka 
Published: March 2007

SummaryWe study the optimal design of switching measurements of small Josephsonjunction circuits which operate in the macroscopic quantum tunnelling regime. In the experiment, sequences of current pulses are applied to the Josephson junction sample, while the voltage over the structure is monitored. The appearance of a voltage pulse to a single applied current pulse, being governed by the laws of quantum mechanics, is purely random. Starting from the D-optimality criterion we derive the optimal design for the estimation of the unknown parameters of the underlying Gumbel-type distribution. As a practical method for the measurements, we propose a sequential design that combines heuristic search for initial estimates and maximum likelihood estimation. The design presented has immediate applications in the area of superconducting electronics, implying faster data acquisition. The experimental results presented confirm the usefulness of the method.
Semiparametric Latent Variable Regression Models for Spatiotemporal Modelling of Mobile Source Particles in the Greater Boston Area
Authors: Gryparis Alexandros , Coull Brent A. , Schwartz Joel , Suh Helen H. 
Published: March 2007

SummaryTraffic particle concentrations show considerable spatial variability within a metropolitan area. We consider latent variable semiparametric regression models for modelling the spatial and temporal variability of black carbon and elemental carbon concentrations in the greater Boston area. Measurements of these pollutants, which are markers of traffic particles, were obtained from several individual exposure studies that were conducted at specific household locations as well as 15 ambient monitoring sites in the area. The models allow for both flexible non-linear effects of covariates and for unexplained spatial and temporal variability in exposure. In addition, the different individual exposure studies recorded different surrogates of traffic particles, with some recording only outdoor concentrations of black or elemental carbon, some recording indoor concentrations of black carbon and others recording both indoor and outdoor concentrations of black carbon. A joint model for outdoor and indoor exposure that specifies a spatially varying latent variable provides greater spatial coverage in the area of interest. We propose a penalized spline formulation of the model that relates to generalized kriging of the latent traffic pollution variable and leads to a natural Bayesian Markov chain Monte Carlo algorithm for model fitting. We propose methods that allow us to control the degrees of freedom of the smoother in a Bayesian framework. Finally, we present results from an analysis that applies the model to data from summer and winter separately.
Estimating Efficacy in a Proposed Randomized Trial With Initial and Later Non-Compliance
Authors: Baker Stuart G. , Frangakis Constantine , Lindeman Karen S. 
Published: March 2007

Summary
A controversial topic in obstetrics is the effect of walking on the probability of Caesarean section among women in labour. A major reason for the controversy is the presence of non-compliance that complicates the estimation of efficacy, the effect of treatment received on outcome. The intent-to-treat method does not estimate efficacy, and estimates of efficacy that are based directly on treatment received may be biased because they are not protected by randomization. However, when non-compliance occurs immediately after randomization, the use of a potential outcomes model with reasonable assumptions has made it possible to estimate efficacy and still to retain the benefits of randomization to avoid selection bias. In this obstetrics application, non-compliance occurs initially and later in one arm. Consequently some parameters cannot be uniquely estimated without making strong assumptions. This difficulty is circumvented by a new study design involving an additional randomization group and a novel potential outcomes model (principal stratification).
Psychotropic Drug Classification Based on Sleep–Wake Behaviour of Rats
Authors: Wouters Kristien , Ahnaou Abdellah , Abrahantes Jose Cortinas , Molenberghs Geert , Geys Helena , Bijnens Luc , Drinkenburg Wilhelmus H. I. M. 
Published: March 2007

Summary
The aim of the paper is to present methodology for the classification of potential psychotropic drugs on the basis of their activity. We first sketch the background of this class of drugs and then zoom in on so-called pharmacoelectroencephalogram studies. These data pose some statistical challenges. For classification purposes, we propose a flexible hierarchical discriminant analysis tool, allowing us to take the specific nature of the drug class into account, as well as the features of the mixed models, in combination with fractional polynomials, fitted to the electroencephalogram data. The method is evaluated against the background of existing methods. The method's performance is studied by using a comprehensive analysis of a large electroencephalogram data set.
Juvenile‐onset neuronal ceroid lipofuscinosis with infantile CLN1 mutation and palmitoyl‐protein thioesterase deficiency
Authors: Kälviäinen R. , Eriksson K. , Losekoot M. , Sorri I. , Harvima I. , Santavuori P. , Järvelä I. , Autti T. , Vanninen R. , Salmenperä T. , Van Diggelen O. P. 
Published: March 2007

Accurate diagnosis, especially in progressive hereditary diseases, is essential for the treatment and genetic counseling of the patient and the family. Neuronal ceroid lipofuscinoses (NCL) are amongst the most common groups of neurodegenerative diseases. Infantile, juvenile, and adult‐onset types with multiple genotype–phenotype associations have been described. A fluorimetric enzyme assay for palmitoyl protein thioesterase (PPT) from leukocytes and fibroblasts has been previously developed to confirm the diagnosis of infantile NCL. We describe a patient with juvenile‐onset NCL phenotype with a new CLN1 mutation and deficient PPT activity.Over 40 different mutations have been found in patients with PPT deficiency, indicating that screening for known mutations is not an efficient way to diagnose this disorder. Therefore, PPT enzyme analysis should precede mutation analysis in suspected PPT deficiency, particularly in patients with granular osmiophilic deposits (GROD) or in patients who have negative ultrastructural data. The use of enzyme assay led to the diagnosis of this patient with juvenile‐onset Finnish variant NCL with PPT deficiency, and we expect that greater awareness of the utility of the enzymatic assay may lead to identification of other similar cases awaiting a definitive diagnosis.
Blood pressure and heart rate in parkinsonian patients with and without wearing‐off
Authors: Pursiainen V. , Korpelainen J. T. , Haapaniemi T. H. , Sotaniemi K. A. , Myllylä V. V. 
Published: March 2007

Our study aimed to investigate the cardiovascular autonomic regulation related to the wearing‐off phenomenon in Parkinson's disease (PD). We measured blood pressure (BP) and heart rate (HR) at rest and during orthostatic test in 16 patients with PD with wearing‐off and in 15 patients with PD without wearing‐off both before (baseline) and repetitively at 1‐h intervals for up to 4 h after the morning PD medication dose.The patients with wearing‐off had fluctuation of BP during the observation period, BP increasing when the motor performance worsened and vice versa. The mean supine BP was at its highest at the baseline measurement (patients with wearing‐off, 145 ± 18 mmHg; patients without wearing‐off, 138 ± 17 mmHg), fell during the first hour (patients with wearing‐off, 119 ± 17 mmHg; patients without wearing‐off, 126 ± 18 mmHg), and then rose again toward the end of the observation period (patients with wearing‐off, 136 ± 15 mmHg; patients without wearing‐off, 138 ± 18 mmHg). This BP change was statistically significant only in PD patients with wearing‐off (P < 0.001).In conclusion, BP seems to fluctuate with motor impairment in PD patients with wearing‐off. This fluctuation may represent autonomic dysfunction caused by the PD process itself, the effect of PD medication, or both.
Hepatocellular carcinoma presenting as nervous system involvement
Authors: Chen S.‐F. , Tsai N.‐W. , Lui C.‐C. , Lu C.‐H. , Huang C.‐R. , Chuang Y.‐C. , Cheng Y.‐F. , Kuo C.‐H. , Chang W.‐N. 
Published: March 2007

To analyze the clinical features of hepatocellular carcinoma (HCC) in patients with signs and symptoms of nervous system involvement as the initial presentation.Over a period of 11 years (January 1993 to December 2003), 15 008 HCC patients were identified at the Chang Gung Memorial Hospital in Kaohsiung, Taiwan. Amongst them, 42 cases had nervous system involvement, of which six had nervous system involvement as their initial presentation. These six cases were enrolled in this study and their clinical and laboratory data were analyzed. The clinical features of the other 36 HCC cases with nervous system involvement were also analyzed for comparison.The six cases were all males, aged 36–68 years old. The involved parts of the nervous system were the cerebellar hemisphere (one), the frontal lobe (one), the sphenoid sinus, sellar turcica, and cavernous sinus (one), the cervical spine (one), and the thoracic spine (two). Their corresponding neurologic presentations were back pain, headache, consciousness disturbance, visual disturbance, and limb weakness. Whilst three out of six patients presenting with nervous system manifestations were found to have concurrent systemic metastases in other expected sites (lung, bone), three had isolated nervous system involvement even after extensive work up. The associated medical conditions of the six cases included hepatitis B (three), hepatitis C (one), liver cirrhosis (two), portal vein thrombosis (three), and diabetes mellitus (two). All the six died within 9 months after the detection of nervous system involvement.The prevalence of nervous system involvement in HCC patients is 0.28% (42/15088), with 0.04% (6/15088) having this as their initial presentation. The prognosis of HCC with nervous system involvement is grave. Their clinical and laboratory data are not unique but the diagnosis could only be confirmed by hepatic and nervous system imaging studies, histopathologic examination, and serum alpha‐fetoprotein detection. This consideration should be emphasized especially in areas that are hyperendemic for HCC and if the original focus of metastatic lesion is obscure.
Exploring the Concept of Causal Power in a Critical Realist Tradition
Authors: KAIDESOJA TUUKKA 
Published: March 2007

ABSTRACTThis article analyses and evaluates the uses of the concept of causal power in the critical realist tradition, which is based on Roy Bhaskar's philosophy of science. The concept of causal power that appears in the early works of Rom Harré and his associates is compared to Bhaskar's account of this concept and its uses in the critical realist social ontology. It is argued that the concept of emergence should be incorporated to any adequate notion of causal power. The concept of emergence used in Bhaskar and other critical realists’ works is shown to be ambiguous. It is also pointed out that the concept of causal power should be analysed in an anti‐essentialist way. Ontological and methodological problems that vitiate Bhaskar's transcendental account of the concept of causal power are examined. Moreover, it is argued that the applications of the concept of causal power to mental powers, reasons, and social structures in the critical realist social ontology are problematic. The paper shows how these problems might be avoided without giving up the concept of causal power and the notion of structural social causation.
For Emergence: Refining Archer's Account of Social Structure
Authors: ELDER‐VASS DAVE 
Published: March 2007

ABSTRACTThe question of social structure and its relationship to human agency remains one of the central problems of social theory. One of the most promising attempts to provide a solution has been Margaret Archer's morphogenetic approach, which invokes emergence to justify treating social structure as causally effective. Archer's argument, however, has been criticised by a number of authors who suggest that the examples she cites can be explained in reductionist terms and thus that they fail to sustain her claim for the independent causal effectiveness of social structure. This paper offers an alternative argument to support the emergentist claim for the causal effectiveness of social structure, and shows how this argument refutes a representative critique of social emergence.
Testing the ‘free radical theory of aging’ hypothesis: physiological differences in long‐lived and short‐lived colubrid snakes
Authors: Robert Kylie A. , Brunet‐Rossinni Anja , Bronikowski Anne M. 
Published: March 2007

SummaryWe test the ‘free radical theory of aging’ using six species of colubrid snakes (numerous, widely distributed, non‐venomous snakes of the family Colubridae) that exhibit long (> 15 years) or short (< 10 years) lifespans. Because the ‘rate of living theory’ predicts metabolic rates to be correlated with rates of aging and oxidative damage results from normal metabolic processes we sought to answer whether physiological parameters and locomotor performance (which is a good predictor of survival in juvenile snakes) mirrored the evolution of lifespans in these colubrid snakes. We measured whole animal metabolic rate (oxygen consumption ), locomotor performance, cellular metabolic rate (mitochondrial oxygen consumption), and oxidative stress potential (hydrogen peroxide production by mitochondria). Longer‐lived colubrid snakes have greater locomotor performance and reduced hydrogen peroxide production than short‐lived species, while whole animal metabolic rates and mitochondrial efficiency did not differ with lifespan. We present the first measures testing the ‘free radical theory of aging’ using reptilian species as model organisms. Using reptiles with different lifespans as model organisms should provide greater insight into mechanisms of aging.
ADHD ‐ Do Guidelines Translate Into Service?
Authors: Moosa Faizal , Lohawala Abbas 
Published: March 2007

Background:  ADHD is a condition with wide ranging implications for children diagnosed with it, health professionals and the agencies setting benchmarks for good practice.Aim:  We set out to measure the adherence of our service to guidelines and to identify service needs.Method:  An audit of cases referred and diagnosed with ADHD during 2004–2005.Results:  The service scored well in areas of assessment and management with stimulants. Potential areas to be addressed included age of referral, differences in referrals across ethnic groups, providing psychosocial interventions coupled with medication and shared care.Conclusion:  It is possible to provide a service that adheres as closely as possible to the guidelines.
Defining Indecency as an Artifact of Cultural Policy
Authors: Wallman Kathleen 
Published: March 2007

AbstractThis article examines the United States’ enforcement of indecency norms in the broadcast arena to discern how it illuminates cultural policy. The article looks at several examples of how enforcement of indecency norms has contributed to the development of an indecency policy that is in tension with other aspects of cultural policy including diversity of voices and localism.
Limitations of the Human‐PBL‐SCID Mouse Model for Vaginal Transmission of HIV‐1
Authors: D'Cruz Osmond J. , Uckun Fatih M. 
Published: March 2007

ProblemSCID mice reconstituted with human peripheral blood lymphocytes (PBL) are amenable to vaginal transmission of HIV‐1. We investigated the effectiveness of this model to establish systemic HIV‐1 infection.Method of studyEighty progesterone‐primed C.B‐17 SCID mice were reconstituted with human‐PBLs and intravaginally inoculated with CCR5 HIV‐1 (BaL or 92BR09) infected human‐PBLs in the presence of human semen. After two weeks, viral RNA load in spleen, peritoneal lavage (PL), and serum was quantitated by the nucleic acid sequence‐based amplification method.ResultsIn five independent experiments, spleen from 8/60 (13.3%), PL from 7/60 (11.6%), and serum from 16/56 (28.5%) mice were positive for BaL HIV‐1 infection. Similarly, spleen from 4/20 (20%), PL from 1/20 (5%) and serum from 5/20 (25%) mice vaginally inoculated with 92BR09‐infected human‐PBLs were positive for HIV‐1. A one‐sided power analysis using normal approximation revealed that at 5% significance level, the overall response rate need to increase form 0.29 to 0.9 and 80% of the control groups needs to achieve a response rate between 6/10 and 9/10 to make the assay feasible.ConclusionThe incidence of vaginal transmission of CCR5 HIV‐1 in the human‐PBL‐SCID mouse was low and variable, which constitutes a major disadvantage for preclinical evaluation of vaginal microbicides.