bluuebunny/crossref_metadata_2025 huggingface dataset:
Taxon‐specific reaction norms to predator cues in a hybridDaphniacomplex
Authors: WOLINSKA JUSTYNA , LÖFFLER ASTRID , SPAAK PIET
Published: March 2007

1. Previous studies have shown that interspecific hybridisation is common among taxa from theDaphnia galeata/hyalina/cucullataspecies complex. We investigated the influence of predator kairomones on the morphology and life histories of nine clones belonging to three taxa (pureD. galeata, F1hybrids betweenD. galeataandD. hyalina, and backcrossedD. hyalina) of this species complex. Predators exerting positive (fish) and negative (Chaoboruslarvae) size‐selective predation were tested.

2. The most responsive traits were size at maturity and size of neonates. Despite large between‐clone variation, discriminant analysis revealed that the three taxa were distinct from each other in key life‐history traits. F1hybrids did not react in an intermediate way compared to the other taxa: the multivariate distances between F1hybrids and either taxon were larger than between pureD. galeataand backcrossedD. hyalina.

3. The average plasticity (calculated across all traits) was similar for all three taxa. With regard to the size at maturity and neonate body size, the strength of the response was a function of the intrinsic values of these traits expressed in the control. For example, for size at maturity, smaller individuals showed a significantly stronger reaction toChaoboruskairomones than larger ones.

4. Finally, we monitored seasonal changes in body size, egg number and population density of pureD. galeataand F1hybrids in Greifensee (Switzerland). The two taxa experienced similar seasonal changes in body size but, on some sampling dates, they differed in mean egg number. The observed seasonal changes inDaphniabody size were consistent with what would be expected if the predator assemblage shifted from fish toChaoborusover the course of the summer. The fluctuations in the frequencies ofDaphniataxa, however, were not related to seasonal variation inDaphniabody size.

5. Experimental data suggest that temporally heterogeneous predation regimes might be an important condition stabilising the co‐occurrence ofDaphniahybrids with parental taxa. Predation regimes, however, cannot solely explain dynamic changes in taxon frequency in Greifensee.
HLA‐B*9518 allele identified in the Chinese population†
Authors: An S. P. , Yan L. N. , Li S. Y. , Dong Z. , Dong L. , Xie J. H. , Yuan Y. H.
Published: March 2007

We report here a novel HLA‐B*9518 allele by sequence‐based typing in the Chinese population. The new B*9518 is identical to B*150101 with an exception of one base substitution at position 19 of exon 3 where a ‘G’ change to ‘T’ resulting in codon 97 changed from AGG (Arg) to ATG (Met).
Sequence‐based typing characterization of the novel HLA‐Cw*1609 allele in the Moroccan Chaouya group†
Authors: Canossi A. , Liberatore G. , Del Beato T. , Oumhani K. , Adorno D.
Published: March 2007

The novel human leukocyte antigen (HLA)‐Cw*1609 allele was identified by sequence‐based typing in a Moroccan Chaouya donor. It differs from the closest Cw*1602 by only one nucleotide (C → G) at position 244 in exon 2 (Glu to Gln at codon 58 in α1 domain).
Low frequency of the disease‐associated DRB1*15‐DQB1*06 haplotype may contribute to the low prevalence of multiple sclerosis in Sami
Authors: Harbo H. F. , Utsi E. , Lorentzen Å. R. , Kampman M. T. , Celius E. G. , Myhr K.‐M. , Lie B. A. , Mellgren S. I. , Thorsby E.
Published: March 2007

This study confirms a low frequency of multiple sclerosis (MS) among Sami. Only 12 Sami with a diagnosis of MS were identified in the Norwegian Sami population, which represents a significantly lower prevalence of MS in Sami (30/105) compared with other Norwegians (73–164/105). The clinical characteristics as well as the results of human leukocyte antigen (HLA)‐DRB1 and ‐DQB1 typing of the Sami MS patients are reported, showing that three (27%) of the Sami MS patients carried the MS‐associated HLA‐DRB1*15‐DQB1*06 haplotype. Interestingly, the DRB1*15‐DQB1*06 haplotype had a significantly reduced frequency among Sami controls (0.086) compared with non‐Sami Norwegian controls (0.163) (Pcorrected = 0.015). The low frequency of the disease‐associated DRB1*15‐DQB1*06 haplotype in the Sami population may contribute to the low prevalence of MS in Sami, in addition to other yet unidentified genetic and environmental factors.
HLA‐DQB1*0317 is a novel allele with an unusual DR‐DQ haplotype†
Authors: Chu C.‐C. , Lin C.‐Y. , Trejaut J. A. , Wu M.‐M. , Lin M.
Published: March 2007

HLA‐DQB1*0317 may have arisen by gene conversion from the DQB1*030302 backbone, leading to one amino acid change from Leu to Gly at codon 26.
Epistatic interaction between FCRL3 and MHC in Spanish patients with IBD
Authors: Martínez A. , Núñez C. , Martín M. C. , Mendoza J. L. , Taxonera C. , Díaz‐Rubio M. , De La Concha E. G. , Urcelay E.
Published: March 2007

Inflammatory bowel disease (IBD), which comprises ulcerative colitis (UC) and Crohn’s disease (CD), shows a multifactorial origin, with genetic and environmental factors involved. Although the genetic influence is clear for both diseases, the genetics involved is complex and epistatic interactions with other genes probably exist. The Fc receptor‐like 3 gene (FCRL3) maps to the human chromosome 1q21‐22 and certain single nucleotide polymorphisms (SNPs) in its promoter have been associated with some autoimmune diseases. Our aim was to study the role of two promoter SNPs of the FCRL3 gene (−169A>G, rs7528684 and −110C>T, rs11264799) in patients with IBD and their interaction with HLA‐DRB1 and CARD15 in patients with UC and CD, respectively. A case–control study with 311 patients with CD, 324 patients with UC and 497 healthy controls was performed. All the individuals were White Spaniards. No significant associations were found between any FCRL3 SNP and CD or UC, but the stratification in patients with UC by human leukocyte antigen (HLA) showed a significant increase in heterozygosity at the FCRL3 locus, especially −169 AG (AG vs AA+GG, P= 0.0027, odds ratio = 3.6, 95% confidence interval 1.4−2.9), when HLA‐DRB1*0103 carrier patients were compared with HLA‐DRB1*0103 noncarriers. Our data suggest an epistatic interaction between genes in chromosomes 6p21 and 1q21‐22, marked, respectively, by HLA‐DRB1*0103 and FCRL3−169 AG.
Sequence variation within the major histocompatibility complex subregion centromeric of HLA class II in type 1 diabetes
Authors: Van Der Slik A. R. , Van Den Eng I. , Eerligh P. , Doxiadis I. I. N. , Koeleman B. P. C. , Roep B. O. , Giphart M. J.
Published: March 2007

The extended major histocompatibility complex (xMHC) has been studied intensively with regard to type 1 diabetes (T1D) predisposition. So far, little attention has been given to the subregion centromeric of MHC class II. We selected five single nucleotide polymorphisms in genes with potential immune‐related functions in the genomic regions of death‐domain‐associated protein 6 (DAXX, apoptosis associated), TAP‐binding protein (TAPBP, human leukocyte antigen class I loading) and retinoic acid receptor beta (RXRB, vitamin D receptor function) that may bear relevance to the pathogenesis of T1D. A total of 277 unrelated individuals with juvenile‐onset T1D and 286 control subjects were genotyped using sequence‐specific priming–polymerase chain reaction. The genotype and allelic frequencies of the markers tested were not significantly different between patients and control subjects. Subsequent haplotype analysis showed six DAXX‐TAPBP‐RXRB haplotypic configurations. No difference was observed between patients and control cohorts when stratified for T1D high‐risk DQ2‐DR17 and DQ8‐DR4 haplotypes. However, the distribution of these haplotypes affected T1D susceptibility encoded by the intermediate risk haplotypes DQ5‐DR1 and DQ2‐DR7 by increasing and decreasing susceptibility, respectively. We propose that studying genetic variants in the xMHC may be particularly rewarding to define disease pathways in patients displaying intermediate risk DQ‐DR haplotypes.
Polymorphism of the transmembrane region of the MICA gene and human brucellosis†
Authors: Bravo M. J. , Colmenero J. D. , Martín J. , Alonso A. , Caballero A.
Published: March 2007

We investigated the polymorphism of the transmembrane region of the MICA gene (major histocompatibility complex class I chain‐related gene A) in relation to susceptibility to human brucellosis. We typed 114 patients with brucellosis and 121 healthy controls for MICA transmembrane polymorphism with polymerase chain reaction methods combined with fluorescent technology. We found a significant decrease in the frequency of the MICA‐A4 allele in the patients with brucellosis compared with the controls (4.4% vs 10.3%, Pc = 0.03). The frequency of the MICA‐A5 allele was increased in the group of patients with focal complications (15% vs 38%, Pc = 0.004). Our data suggest the MICA‐A4 allele shows a tendency to be protective against infection by Brucella melitensis. Furthermore, the MICA‐A5 allele appears to confer susceptibility to focal forms in patients with brucellosis.
The duplicitous effects of interleukin 4 on tumour immunity: how can the same cytokine improve or impair control of tumour growth?
Authors: Olver S , Apte S , Baz A , Kienzle N
Published: March 2007

Successful tumour immunity relies on innate and adaptive immune responses, with cytokines like interleukin 4 (IL‐4) known to influence tumour clearance in both positive and negative ways. Here, we summarise some of the murine tumour models used over the past two decades to assess the impact of IL‐4 on tumour immunity, with emphasis on the effects of IL‐4 on the tumour‐induced CD8 T‐cell response. These data are compared with our own recent studies showing that IL‐4 impairs CD8+ T‐cell‐mediated immunity against the mastocytoma cell line P815 expressing the immunogenic HLA‐CW3 gene; moreover, we hypothesise that quantitative and qualitative differences in the HLA‐CW3‐induced CD8+ T‐cell response impair control of tumour growth and aid the development of secondary tumours. We conclude that the duplicitous effects of IL‐4 on tumour immunity depend on the type of effector cell (adaptive/innate) mediating tumour clearance and whether tumour growth depends on stromal infrastructure. Thus, the search for factors that improve or weaken the effectiveness of tumour‐specific T cells has to be continued to improve modern approaches of immunotherapy against cancer.
The ttgGHI solvent efflux pump operon of Pseudomonas putida DOT‐T1E is located on a large self‐transmissible plasmid
Authors: Rodríguez‐Herva José J. , García Vanina , Hurtado Ana , Segura Ana , Ramos Juan L.
Published: March 2007

Pseudomonas putida DOT‐T1E is a solvent‐tolerant strain able to grow in the presence of > 1% (v/v) toluene in the culture medium. A set of multidrug efflux pumps have been found to play a major role in the tolerance of this bacterium to organic solvents (Rojas et al., J Bacteriol 183: 3967–3973). In the course of studies of the mechanisms underlying solvent tolerance in DOT‐T1E, we isolated a spontaneous solvent‐sensitive mutant derivative which had lost the genes encoding the TtgGHI efflux pump, the most important extrusion element in quantitative terms. Genomic comparisons between the mutant and its parental strain by microarray analysis revealed that in addition to the ttgVW‐ttgGHI gene cluster, another group of genes, highly similar to those found in the Tn4653A and ISPpu12 transposable elements of the TOL plasmid pWW0 from P. putida mt‐2, were also absent from this strain. Further analysis demonstrated that strain DOT‐T1E harboured a large plasmid (named pGRT1) that was lost from the solvent‐sensitive mutant. Mapping analysis revealed that the ttgVW‐ttgGHI genes and the Tn4653A‐like transposon are borne by the pGRT1 plasmid. Plasmid pGRT1 is highly stable and its frequency of loss is below 10−8 per cell per generation under a variety of growth conditions, including nutritional and physical stresses. The pGRT1 plasmid is self‐transmissible, and its acquisition by the toluene‐sensitive P. putida KT2440 and Pseudomonas aeruginosa PAO1 increased the recipient's tolerance to toluene up to levels similar to those exhibited by P. putida DOT‐T1E. We discuss the importance and potential benefits of this plasmid for the development of bacteria with enhanced solvent tolerance, and its potential impact for bioremediation and whole‐cell biotransformations.
Knowledge Networks and Careers: Academic Scientists in Industry–University Links*
Authors: Lam Alice
Published: March 2007

abstract Careers are central to our understanding of the knowledge creation dynamics of network organizations. Based on the example of R&D project collaboration between firms and universities, this paper examines the emerging forms of career models that support knowledge flows between organizations. It explores how some large firms in the high‐technology sectors have sought to break away from the limitations of internal R&D and firm‐based careers for scientists by engaging in external collaborative projects to gain access to the open knowledge networks of university researchers. It examines how the firms seek to forge close institutional ties with their university partners and develop network career structures in order to engage academic scientists in joint knowledge production. It argues that firms have sought to extend their human resource and knowledge boundaries into the established internal labour markets of the universities with which they collaborate, leading to the formation of a pool of joint human resources with work experiences and career patterns straddling the two sectors. The paper develops the concept of an ‘overlapping internal labour market’ to provide a conceptual bridge between internal labour markets and network organizations.
Chinese Indonesians in a rapidly changing nation: Pressures of ethnicity and identity
Authors: Turner Sarah , Allen Pamela
Published: March 2007

Abstract: Throughout periods of political instability and economic adversity – from Dutch colonial rule, through President Suharto's period in office, to more recent times – ethnic Chinese in Indonesia have been recurrent scapegoats for violence. Suharto, especially, manipulated local perceptions of the Chinese in the economic and political arenas, to suit the needs of his government. Yet, circumstances have changed since the 1998 riots in Indonesia and Suharto's departure. Subsequent presidents have introduced legislation aimed at reducing legal restrictions on Chinese Indonesians and they, in turn, are beginning to have greater public voice through a diversity of outlets. These include the growth of numerous new print and television media; a flourishing literature sphere; the rise of a variety of political parties, both ethnicity‐based and more wide‐ranging; and the development of non‐political organisations, some tackling discrimination and others focusing upon Chinese sociocultural needs. These channels are facilitating the appearance of new and re‐emerging ethnic Chinese identities, some surfacing from over 30 years of imposed dormancy. This paper is a preliminary investigation of manifestations of these identities among ethnic Chinese in Indonesia's contemporary public realm.
Linguistic and Religious Influences on Foreign Trade: Evidence from East Asia*
Authors: Guo Rongxing
Published: March 2007

Using a modified gravity model and the cross‐sectional data of East Asian economies, the present paper presents evidence that supports the view that the effect of distance‐related transaction costs on trade tends to fall over time. Overall religious influence on foreign trade exists in the post‐Cold War period but not during the Cold War period. The effects of language on inter‐regional trade and of religion on intra‐regional trade both weaken over time. In all cases, religion tends to have more significant influences on intra‐regional trade than language, and language tends to exert more significant influences on inter‐regional trade than religion. Finally, from 1985 to 1995 there is an indication that: (i) English becomes more important for inter‐regional trade; (ii) Bahasa, English and Khmer become less important for intra‐regional trade; and (iii) Chinese plays an increasing role in both intra‐regional and inter‐regional trade.
Language and Theory of Mind: A Study of Deaf Children
Authors: Schick Brenda , De Villiers Peter , De Villiers Jill , Hoffmeister Robert
Published: March 2007

Theory‐of‐mind (ToM) abilities were studied in 176 deaf children aged 3 years 11 months to 8 years 3 months who use either American Sign Language (ASL) or oral English, with hearing parents or deaf parents. A battery of tasks tapping understanding of false belief and knowledge state and language skills, ASL or English, was given to each child. There was a significant delay on ToM tasks in deaf children of hearing parents, who typically demonstrate language delays, regardless of whether they used spoken English or ASL. In contrast, deaf children from deaf families performed identically to same‐aged hearing controls (N=42). Both vocabulary and understanding syntactic complements were significant independent predictors of success on verbal and low‐verbal ToM tasks.
Do the Eyes Have It? Inferring Mental States From Animated Faces in Autism
Authors: Back Elisa , Ropar Danielle , Mitchell Peter
Published: March 2007

The ability of individuals with autistic spectrum disorders (ASD) to infer mental states from dynamic and static facial stimuli was investigated. In Experiment 1, individuals with ASD (10‐ to 14‐year olds; N=18) performed above chance but not as well as controls. Accuracy scores for mental states did not differ between dynamic and static faces. Furthermore, participants with ASD gained higher scores when the eyes conveyed information than when this region remained static and neutral. Experiment 2 revealed that those with ASD (11‐ to 15‐year olds; N=18) were as successful as controls in recognizing mental states when the eyes were presented in isolation or in the context of the whole face. Findings challenge claims that individuals with ASD are impaired at inferring mental states from the eyes.
Linkages Between Delayed Children's Social Interactions With Mothers and Peers
Authors: Guralnick Michael J. , Neville Brian , Hammond Mary A. , Connor Robert T.
Published: March 2007

The social dimensions of family–peer linkages of 4‐ to 6‐year‐old children (N=63) with developmental delays (IQ range, 50–80) were examined in this study. Hierarchical regressions revealed consistent and meaningful patterns of association relating children's influence attempts directed toward their mothers and their interactions with peers. A similar association with peer interactions was found for children's ability to obtain compliance from their mothers. Evidence suggested the existence of a core behavioral pattern that children exhibit with different partners and in different contexts. The role of horizontal forms of parent–child interactions in promoting the peer relationships of children with delays was suggested, particularly in terms of an intervention approach for this group of children.
Teachers' Education, Classroom Quality, and Young Children's Academic Skills: Results From Seven Studies of Preschool Programs
Authors: Early Diane M. , Maxwell Kelly L. , Burchinal Margaret , Alva Soumya , Bender Randall H. , Bryant Donna , Cai Karen , Clifford Richard M. , Ebanks Caroline , Griffin James A. , Henry Gary T. , Howes Carollee , Iriondo‐Perez Jeniffer , Jeon Hyun‐Joo , Mashburn Andrew J. , Peisner‐Feinberg Ellen , Pianta Robert C. , Vandergrift Nathan , Zill Nicholas
Published: March 2007

In an effort to provide high‐quality preschool education, policymakers are increasingly requiring public preschool teachers to have at least a Bachelor's degree, preferably in early childhood education. Seven major studies of early care and education were used to predict classroom quality and children's academic outcomes from the educational attainment and major of teachers of 4‐year‐olds. The findings indicate largely null or contradictory associations, indicating that policies focused solely on increasing teachers' education will not suffice for improving classroom quality or maximizing children's academic gains. Instead, raising the effectiveness of early childhood education likely will require a broad range of professional development activities and supports targeted toward teachers' interactions with children.
Relation Between Reading Problems and Internalizing Behavior in School for Preadolescent Children From Economically Disadvantaged Families
Authors: Ackerman Brian P. , Izard Carroll E. , Kobak Roger , Brown Eleanor D. , Smith Clare
Published: March 2007

This longitudinal study of 105 economically disadvantaged children examined the relation between reading problems and internalizing behavior in 3rd‐ and 5th‐grade assessments (8‐ to 12‐year olds). The variable‐centered results showed that reading problems predicted change in internalizing behavior in the context of child and family predictors. The person‐centered results showed that children with reading problems in both grades had higher internalizing scores in 5th grade but not in 3rd grade than children with reading problems in 3rd grade or no problems. Child‐reported negative emotion experiences varied similarly across grade. The results tie reading problems to emotional distress in school and support conclusions about the direction of effects and the internalization of academic difficulty for disadvantaged children.
To Lie or Not to Lie: To Whom and Under What Circumstances
Authors: Perkins Serena A. , Turiel Elliot
Published: March 2007

This research examined adolescents' judgments about lying to circumvent directives from parents or friends in the moral, personal, and prudential domains. One hundred and twenty‐eight adolescents (12.1–17.3 years) were presented with situations in which an adolescent avoids a directive through deception. The majority of adolescents judged some acts as acceptable, including deception regarding parental directives to engage in moral violations and to restrict personal activities. Other acts of deception were judged as unacceptable, including deception of parents regarding prudential acts, as well as deception of friends in each domain. In addition, lying to conceal a misdeed was negatively evaluated. Most adolescents thought that directives from parents and friends to engage in moral violations or to restrict personal acts were not legitimate, whereas parental directives concerning prudential acts were seen as legitimate. Results indicate that adolescents value honesty, but sometimes subordinate it to moral and personal concerns in relationships of inequality.
Relating Effortful Control, Executive Function, and False Belief Understanding to Emerging Math and Literacy Ability in Kindergarten
Authors: Blair Clancy , Razza Rachel Peters
Published: March 2007

This study examined the role of self‐regulation in emerging academic ability in one hundred and forty‐one 3‐ to 5‐year‐old children from low‐income homes. Measures of effortful control, false belief understanding, and the inhibitory control and attention‐shifting aspects of executive function in preschool were related to measures of math and literacy ability in kindergarten. Results indicated that the various aspects of child self‐regulation accounted for unique variance in the academic outcomes independent of general intelligence and that the inhibitory control aspect of executive function was a prominent correlate of both early math and reading ability. Findings suggest that curricula designed to improve self‐regulation skills as well as enhance early academic abilities may be most effective in helping children succeed in school.
A framework for quad/triangle subdivision surface fitting: Application to mechanical objects
Authors: Lavoué Guillaume , Dupont Florent , Baskurt Atilla
Published: March 2007

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

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

Computer 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

Light‐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.
Demographic Change and Policy Responses: Implications for the Global Economy
Authors: Tyers Rod , Shi Qun
Published: March 2007

The fertility declines associated with the final phase of the global demographic transition have led to slower population growth and accelerated ageing in developed countries and in several advanced developing countries. A global demographic and economic model is used to assess the implications of these changes for population sizes, age‐gender distributions, labour force growth and their implications for economic performance. A baseline projection that incorporates declining fertility is compared with a hypothetical constant population growth scenario. The results show that slower population growth and ageing reduces average saving rates in industrial regions, yet global investment demand is also slowed and saving rates rise in developing regions, so there is no net tightening of financial markets. Increased aged labour force participation, considered one solution to the resulting rise in aged dependency in advanced regions, is found to redistribute investment in favour of the industrialised regions and hence to accelerate their per capita income growth, while conferring on the other regions compensatory terms of trade improvements. The alternative of replacement migration is found to require inconceivably large population movements. It also impairs real per capita growth in destination regions but by least in Western Europe, where the terms of trade are improved by the immigration.
Exporting and Economic Performance: Firm‐level Evidence of Spanish Manufacturing
Authors: Fariñas José C. , Martín‐Marcos Ana
Published: March 2007

In a previous paper, Delgado, Fariñas and Ruano (2002) report TFP differences between exporters and non‐exporters on the basis of a sample of Spanish manufacturing firms. In this paper, we extend the previous analysis in three directions using a similar data set. First, we investigate additional economic performance differences between exporters and non‐exporters. Second, we measure TFP differences estimating production functions that control for unobserved heterogeneity and simultaneity bias. Third, we explore the self‐selection and learning‐by‐exporting hypothesis as explanations for the greater performance of exporters. With respect to the results, we confirm that many indicators of economic performance such as productivity, size, wages and innovation are greater in exporting firms. Furthermore, TFP differences between exporters and non‐exporters estimated with parametric methods are remarkably similar to those estimated using index numbers. Finally, performance differences and transition patterns between the export market and the domestic market indicate higher performance for entering exporters with respect to non‐exporters at the moment of entry. We find evidence of selection in the entry and the exit side of the export market. One of the basic results that we obtain indicates that after controlling for self‐selection, the productivity growth of entering exporters does not significantly change with respect to non‐exporters. As the evidence we find indicates no systematic changes in performance between non‐exporters and exporters after entry takes place, we do not confirm the learning‐by‐exporting hypothesis.
Response-Adaptive Randomization for Survival Trials: The Parametric Approach
Authors: Zhang Lanju , Rosenberger William F.
Published: March 2007

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

We 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

Traffic 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

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

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.
Variant Creutzfeldt–Jakob disease: first two indigenous cases in Republic of Ireland. Case report and perspective
Authors: McHugh J. C. , Bradley D. , Hutchinson M. , Brett F. , Heffernan J. , Howley R. , Farrell M. , Tubridy N.
Published: March 2007

The first two cases of indigenous variant Creutzfeldt–Jakob disease (vCJD) in the Republic of Ireland are reported in two men, neither of whom had lived outside Ireland. Both diagnoses were made ante‐mortem based on clinical presentation, brain imaging, positive 14‐3‐3 protein in one case, and tonsillar biopsy. We discuss some of the clinical aspects of vCJD and the significance of these cases in the Irish context.
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.
Pure word deafness and pure anarthria in a patient with frontotemporal dementia
Authors: Iizuka O. , Suzuki K. , Endo K. , Fujii T. , Mori E.
Published: March 2007

A 66‐year‐old right‐handed man developed pure anarthria following pure word deafness. In addition to language disorders, his behavior gradually changed and finally included violence against his wife. Brain magnetic resonance imagings revealed atrophy of the left perisylvian area, which included the inferior half of the precentral gyrus and the upper portion of the superior temporal gyrus, consistent with frontotemporal dementia (FTD). It has been documented as either a disorder of expressive language or as an impaired understanding of word meaning. Unlike with pure anarthria, pure word deafness is not included in the clinical diagnostic current criteria for FTD. However, a large variety of language symptoms can appear in FTD according to the distribution of pathological changes in the frontotemporal cortices. This case suggests that pure word deafness could be a prodomal symptom of FTD.
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.
Treatment of newly diagnosed symptomatic pure low‐grade oligodendrogliomas with PCV chemotherapy
Authors: Lebrun C. , Fontaine D. , Bourg V. , Ramaioli A. , Chanalet S. , Vandenbos F. , Lonjon M. , Fauchon F. , Paquis P. , Frenay M.
Published: March 2007

Based on studies relating to anaplastic oligodendroglioma (OG) chemosensitivity and benefit of time to progression or overall survival, chemotherapy for pure OG has been proposed. Several studies have reported the efficacy of various chemotherapeutic agents in a small number of patients with low‐grade gliomas, e.g. pure astrocytomas, OG or mixed histologies. The 5‐year survival rate varies from 61% to 89% with a mean time to progression of 5 years. We report the outcome of 33 consecutive patients with pure low‐grade OG diagnosed between 1990 and 2006 systematically treated for residual or non‐removable tumor with PCV chemotherapy regimen as the front‐line treatment after surgery. All the tumors were low grade (grade II) pure OG according to the WHO classification. All patients were symptomatic at presentation and underwent neurosurgical procedure for histological diagnosis. Response was evaluated by clinical assessment and brain magnetic resonance imaging. Twenty‐one men and 12 women with a mean age at pathological diagnosis of 46.5 years were studied. The most common first symptom was partial epileptic seizure (73.7%). Six patients (18%) had initial gadolinium enhancement, associated with methoxyisobutyl (MIBI) hypermetabolism (P < 0.001). The resection was partial in seven cases (21%), and 26 patients (79%) had biopsy only. Eleven patients (36%) had a malignant transformation during the follow‐up with a median time to progression of 19 months. Favorable prognostic factors were lack of contrast enhancement (P < 0.0001), and age <40 years (P < 0.0003); 90% of patients were progression‐free at 1 year. Survival rates at 2, 5 and 10 years were 85%, 75% and 50%, respectively. Up‐front chemotherapy with PCV regimen is a good treatment for symptomatic pure low‐grade OG, as it increases the number of progression‐free patients and time to progression. These results suggest that radiotherapy could be postponed until the malignant transformation occurs to delay cognitive side effects of irradiation.
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.