bluuebunny/crossref_metadata_2025 huggingface dataset:
Design and Synthesis of New Thermally Stable Polyesters containing Azo and Phenylthiourea Groups
Authors: Sivadhayanithy Mylsamy , Ravikumar Lingam , Rengaswamy Chelliah
Published: October 2006

A series of new soluble, thermally stable polymers that contain phenylthiourea and azo groups in the polymer backbone were synthesized from a novel bisphenol and diacid chlorides. The novel bisphenol containing phenylthiourea and azo groups was synthesizedinthreesteps. In the first step, 4,4‘-bis(thiourea) biphenyl (BTB) was from 4,4‘-diaminobiphenyl and ammonium thiocynate. The second step involved the diazodization reaction of 4-aminophenol to give the diazonium chloride salt. The third step in the preparation of the monomer was the coupling of bisthiourea (BTB) with the diazonium chloride in the presence of an alkali which resulted in 4,4‘-bis( p-hydroxyphenyl azo thiourea)biphenyl (HP-ATB). The final step was the synthesis of polyesters by polycondensation reaction of this monomer with various acid chlorides (both aromatic and aliphatic). The materials were characterized by solution viscosity, UV-Vis, Fourier transform infrared spectroscopy, 1H NMR, differential scanning calorimetry and thermogravimetric analysis. Solubility of the polymers was also tested with different solvents, which can be an important parameter for the processability of the polymer. The synthesis and characterization of the novel monomer and polymers is discussed herein.
Copolymerization Studies of Urethane Methacrylate and Ladder-Like Polysilsesquioxane Containing Side Chain Methacrylate Groups
Authors: Krishnan P. Santhana Gopala , Shang Christine Tay Shang
Published: October 2006

Urethane methacrylate (UMA) prepolymer was prepared by reacting 2 mole tolylene diisocyanate with 1 mole polyethylene glycol (molecular weight 400) followed by end-capping with 2 mole 2-hydroxyethyl methacrylate in N, N-dimethylformamide (DMF) solvent using stannous octoate as a catalyst. It took 72 h for complete reaction at ambient temperature as determined by monitoring the isocyanate peak at 2269 cm-1. Ladder-like polysilsesquioxane (LPS) containing side chain methacrylate groups was prepared by stepwise coupling polymerization. Different weight fractions of UMA and LPS in DMF were copolymerized using 1% (w/w) dibenzoyl peroxide at 80°C for 24 h followed by post curing at 100°C for 4-5 h in a nitrogen atmosphere. The copolymers were characterized by Fourier transform infrared analysis, solid-state 13C NMR spectroscopy, differential scanning calorimetry (DSC), wide-angle X-ray diffraction (WAXD) and thermogravimetric analysis. No glass transition temperatures were observed for the copolymers by DSC. The WAXD patterns of copolymers showed a broad peak corresponding to the width of double chain of LPS, indicating the incorporation of LPS in copolymers. These copolymers were more resistant to acid medium. The temperature of 5% weight loss increased with increasing silsesquioxane content in both air and nitrogen atmospheres, and verified the incorporation of LPS in the copolymers.
Metaconsumptive Practices and the Circulation of Objectifications
Authors: Shankar Shalini
Published: October 2006

This article analyzes an intersection of materiality and language use. I argue that verbal practices, generally overlooked in material culture studies, are an integral dimension of consumption. Types of talk - both referential and indexical - can illustrate how people mediate relationships with objects, as well as with each other. Drawing on ethnographic research in Silicon Valley, California (1999-2001), I present examples from middle-class South Asian American communities. In these closely-knit social contexts, I examine how people discursively create objectifications through talk and consumption of visual media such as video and photographs. My examination of these language practices reveals that people not only form relationships with objects they own, but also with objectifications - verbal and visual representations - of objects they borrow, rent, or imagine. Social theorists have remarked on how people can use contests of status and display associated with consumption to ascend into higher social classes. I consider how youth and adults engage in language use and consumption to instead display identity and status within their own community.
Ambivalent Heritage
Authors: Chadha Ashish
Published: October 2006

This article examines the significance of colonial cemeteries and explains why they are sites of neglect and decay in contemporary India. By examining the ideological and affective meanings of a colonial funerary landscape like the Park Street cemetery in Calcutta, it shows how monuments of colonial memories have transformed into signs of temporal ruptures, which disturbs the dichotomy between the colonial and the post-colonial. It argues that the discard and abandonment of colonial cemeteries in the postcolonial landscape stems from the ambivalent meaning that such a heritage site generates. Using three pairs of conceptual constructs - Kristeva’s genotext and phenotext; Freud’s melancholy and mourning; and tropological metaphor and metonymy - I demonstrate that this ambivalence is located in an intersection between the funerary monument as a cultural product of a colonial ideology, and as a memorial artifact of personal bereavement.
Expertise and Inability
Authors: Hitchings Russell
Published: October 2006

Material culture, as a concept, is suggestive of control. Yet, when we acknowledge it, it becomes clear that all the physical things we handle have a degree of independence. Indeed, by exploring the ways in which this independence is intimately accommodated, a richer understanding of certain kinds of experience could follow. With this argument in mind, this article travels to some domestic gardens in north London to reconsider the human activities associated with the plants that are found there. In these sites it seems that amicable arrangements of entity only ever become possible through fully embracing the fact that those people involved own only one, amongst many, of the agencies in evidence there. In fact, whilst an idea of a successful gardener can connote an efficient exercise of power, I want to argue that the opposite is actually the case. My contention, therefore, is that, to fully find pleasure from plants, people must become enjoyably expert in understanding that any complete control is always unlikely, and this is a contention with some potentially important implications for current patterns of practice.
Analysing sequential events in clinical trials
Authors: Salter A , Raab G , Day S
Published: October 2006

Background Data from clinical trials where the endpoint is a single survival time are readily analysed by standard methods, most commonly using a semi-parametric proportional hazards approach. However, when the outcome involves two sequential survival times, standard methods may not be applicable.

Methods We consider methods appropriate for the analysis of survival data in clinical trials where there are two distinct, sequential and opposing survival endpoints and where inferences about the second event are of particular interest. Two motivating examples of randomized clinical trials with different designs provide important illustrations of the methodology in practice.

Results Bivariate log-normal survival models are proposed as useful way of modeling such data. These models can be simply implemented in two stages, each of which is a univariate log-normal survival analysis. Different approaches to the analyses are described according to whether a second randomized treatment assignment is made at the time when the first event occurs and the second phase of the study commences. In the absence of a second randomization, the bivariate log-normal model adjusts for selection into the second phase of the study.

Conclusions The investigation of ‘treatment sequences’ should, wherever possible, be handled by repeat randomization, which can then be followed by valid, unbiased analyses. However, in many clinical trial scenarios, this is simply not possible. In this case, the best approach is to consider the data as arising from an observational study, whilst controlling for all appropriate covariates.

Limitations The approach we describe is appropriate for log-normally distributed data but could be generalised to handle other distributions, although the process of model fitting would be less straight-forward.
A Latin American perspective on communication/cultural mediation
Authors: Martín-Barbero Jesús
Published: October 2006

Latin American communication research shows an increasing convergence with cultural studies in terms of its ability to analyze communication and cultural industries as a matrix for both the disruption and reorganization of the social experience. The article argues that it is imperative to reflect on the way in which communication has been transformed into a highly effective mechanism for the insertion of all cultures - whether ethnic, national or local - into the sphere of the market. The article explores the changing configurations in the field of communication research in Latin America, noting the shift in focus from mediation to media and the increasing contribution of an ethnographic perspective, which seems particularly promising when applied to the younger generation’s cultural trajectories.
Citizens and media cultures: hidden behind democratic formality
Authors: Moreno Rosa María Alfaro
Published: October 2006

The relationship between culture and mass media has received much attention among communication scholars in Latin America, especially during the 1980s and 1990s. This period witnessed a shift from understanding culture and mass communication as domination, to an exploration of the complex and politically nuanced roles played by the mass media within the cultural and political fabrics of the region. As such, the ideological and deterministic moorings of the old debates were considerably softened, as writers such as Martín-Barbero redefined the media in terms of cultural mediations. From this perspective, cultural mediations shape the manner in which subjects articulate their relationship to modernity. This article continues this agenda by exploring the complex relationship between culture, politics and democracy.
Culture, neo-liberalism and citizen communication: the case of Radio Tierra in Chile
Authors: Poblete Juan
Published: October 2006

This article analyses the Chilean independent and not-for profit station Radio Tierra In the general context of the work of two key Chilean sociologists, José Joaquín Brunner and Manuel Antonio Garretón, in particular the latter’s theory of an epochal transformation in the relationship between culture and neo-liberalism in Chile over the preceding 30 years. More specifically, it suggests that Radio Tierra makes evident the emergence of a new form of social communication which, in contrast to the traditional liberal model of communication of, and for, information, is more attuned to the new functions of culture in the expansion and implementation of citizenship under conditions of (neo-liberal) globalization. After a discussion of the contemporary media scene and the role of public journalism and alternative communication in Latin America, the article then focuses on the communicational, political and cultural work of Radio Tierra. In 1990, along with the transition to democracy, Radio Tierra (RT) was born in Santiago as an independent station. Using its trajectory, I will try to concretely show some important connections between globalization, neo-liberalism and culture in contemporary Chile.
Channeling blackness, challenging racism: a theatrical response
Authors: Rivero Yeidy M.
Published: October 2006

This article calls attention to the pressing need to explore commercial television’s racial, ethnic, cultural, and gendered representations across the Latin American and Spanish Caribbean region as well as documenting the ways in which non-white citizens are (and have been) coping with their social and televisual marginalization. The performance piece You Don’t Look Like provides a unique opportunity to examine how those who have been excluded from and reconfigured in the local televisual frame have negotiated their invisibility and their constructed Otherness. By reenacting some of Puerto Rico’s scenarios of blackness, You Don’t Look Like questions and denounces the positionality of black citizens in the island’s society, culture, and on television. The article argues that both directly and indirectly, Puerto Rico’s scenarios of blackness not only imply specific geographical sites within the island but also the racialized bodies and cultures that flow back and forth across the Caribbean Sea.
REEzoning in allanite related to changing partition coefficients during crystallization: implications for REE behaviour in an epidote-bearing tonalite
Authors: Beard J. S. , Sorensen S. S. , Gieré B.
Published: October 2006

Allanite is present in most samples of the tonalitic Bell Island Pluton, with an average mode near 0.05 wt.%. Allanite occurs as cores in igneous epidote-clinozoisite and exhibits characteristic and consistent zoning patterns.REE-rich cores (All40-70) grade out towards epidote-clinozoisite withREEbelow electron microprobe detection limits. La, Ce and Pr contents are highest in theREE-richcores of zoned crystals. Nd and Sm contents both initially increase as totalREEdecreases and are highest in intermediate zones. Y contents are generally low throughout, but tend to be highest in analyses with A115-20.The zoning behaviour exhibited by the allanite, specifically the rimward increases in Nd, Sm, and Y, cannot be accounted for by simple fractionation and are best explained by increases in allanite/ melt partition coefficients (Kdvalues) for these elements during crystallization. We propose that the variation inKdvalues reflects modification of the allanite structure with changingREEcontent. These modifications are manifested by changes in colour, extinction, and pleochroism within the zoned crystals and include changes in unit-cell volume and dimensions. The changes inKdvalues are large enough to result in crossingREEpatterns within single allanite crystals. Fractional crystallization of zoned allanite can have noticeable effects onLREEcontents and La/Sm (and almost certainly La/Lu) in magmas. In the Bell Island pluton, 80% of La, but <3% of Y is contained in allanite. Although some of the variation in theLREEchemistry of the pluton is attributable to statistical sampling error, much of it appears to reflect petrogenetic processes that controlledLREEabundance and, ultimately, allanite mode. One sample of Bell Island tonalite is depleted inLREEand has low La/Lu and La/Sm. These chemical features can be modelled by fractionation of zoned allanite.
Thermal expansion of highly silicic nepheline-kalsilite crystalline solutions
Authors: Hovis G. L. , Person E. , Spooner A. , Roux J.
Published: October 2006

We have investigated the thermal expansion of nepheline-kalsilite crystalline solutions having 12.5% excess silicon relative to the stoichiometric composition. It is proposed that differences in the thermal expansion among various members of the series, and also between this series and a previously studied low-Si series, can be explained by three factors: (1) shrinkage of the tetrahedral rings caused by the substitution of Na for K, especially in the case of kalsilite, allows for greater expansion from the increased vibrational amplitude of Na ions with increasing temperature. (2) The occupancy of alkali sites by ions rather than vacancies draws tetrahedral rings inward via electrical attraction to these ions, providing the potential for greater expansion with ionic vibration as temperature increases. (3) Structural differences between nepheline and kalsilite, in particular the existence of two alkali sites in nepheline, account for the increased thermal expansion of K-enriched nepheline relative to Na-nepheline, as the occupation of the larger alkali position by K+ results in greater thermal expansion than is the case with Na+ occupancy of the same sites.
Compositional evolution and cryptic variation in pyroxenes of the peralkaline Lovozero intrusion, Kola Peninsula, Russia
Authors: Kogarko L. N. , Williams C. T. , Woolley A. R.
Published: October 2006

The Lovozero alkaline massif is the largest of the world's layered peralkaline intrusions (∼650 km2). We describe the evolution of clinopyroxene from the liquidus to the late residual stage throughout the whole vertical section (2.5 km thick) of the Lovozero Complex. Microprobe data (∼990 analyses) of the clinopyroxenes define a relatively continuous trend from diopside containing 15–20% hedenbergite and 10–12% aegirine components, to pure aegirine. The main substitutions during the evolution of the Lovozero pyroxenes are (Na,Fe3+,Ti) for (Ca,Mg,Fe2+). The composition of the pyroxene changes systematically upwards through the intrusion with an increase in Na, Fe3+ and Ti and decrease in Ca and Mg.

The compositional evolution of the Lovozero pyroxene reflects primary fractionation processes in the alkaline magma that differentiated in situ from the bottom to the top of the magma chamber as a result of magmatic convection, coupled with the sedimentation of minerals with different settling velocities.

The temperature interval of pyroxene crystallization is very wide and probably extends from 970 to 450°C. The redox conditions of pyroxene crystallization in the Lovozero intrusion were relatively low, approximating the QFM buffer.
Mineralogy of stalactites formed by subaerial weathering of natrocarbonatite hornitos at Oldoinyo Lengai, Tanzania
Authors: Mitchell R. H.
Published: October 2006

Stalactites formed by the chemical weathering of natrocarbonatite lava decorate the roofs of hollow inactive hornitos at Oldoinyo Lengai, Tanzania. The stalactites are composed principally of trona with lesser and very variable amounts of nahcolite, (NaHCO3), thermonatrite (Na2CO3.H2O), aphthitalite [(K,Na)3Na(SO4)2], kogarkoite [Na3(SO4)F], schairerite [Na21 (SO4)7F6Cl], halite and sylvite. Stalactites are considered to form by the evaporation of Ca-free highly alkaline brines seeping from the altered lavas which form the roofs of the hornitos. The principal subaerial weathering products of natrocarbonatite, i.e. pirsonnite, gaylussite, shortite and calcite are not found in the stalactites and are retained in the altered lavas of the homito roof. Fluorine required for the formation of kogarkoite and schairerite is derived from the decomposition of fluorite at high pH (>10). Sulphur is derived from the decomposition of gregoryite.
SVRMHC prediction server for MHC-binding peptides
Authors: Wan Ji , Liu Wen , Xu Qiqi , Ren Yongliang , Flower Darren R , Li Tongbin
Published: October 2006

Background

The binding between antigenic peptides (epitopes) and the MHC molecule is a key step in the cellular immune response. Accuratein silicoprediction of epitope-MHC binding affinity can greatly expedite epitope screening by reducing costs and experimental effort.

Results

Recently, we demonstrated the appealing performance of SVRMHC, an SVR-based quantitative modeling method for peptide-MHC interactions, when applied to three mouse class I MHC molecules. Subsequently, we have greatly extended the construction of SVRMHC models and have established such models for more than 40 class I and class II MHC molecules. Here we present the SVRMHC web server for predicting peptide-MHC binding affinities using these models. Benchmarked percentile scores are provided for all predictions. The larger number of SVRMHC models available allowed for an updated evaluation of the performance of the SVRMHC method compared to other well- known linear modeling methods.

Conclusion

SVRMHC is an accurate and easy-to-use prediction server for epitope-MHC binding with significant coverage of MHC molecules. We believe it will prove to be a valuable resource for T cell epitope researchers.
Goulphar: rapid access and expertise for standard two-color microarray normalization methods
Authors: Lemoine Sophie , Combes Florence , Servant Nicolas , Le Crom Stéphane
Published: October 2006

Background

Raw data normalization is a critical step in microarray data analysis because it directly affects data interpretation. Most of the normalization methods currently used are included in the R/BioConductor packages but it is often difficult to identify the most appropriate method. Furthermore, the use of R commands for functions and graphics can introduce mistakes that are difficult to trace. We present here a script written in R that provides a flexible means of access to and monitoring of data normalization for two-color microarrays. This script combines the power of BioConductor and R analysis functions and reduces the amount of R programming required.

Results

Goulphar was developed in and runs using the R language and environment. It combines and extends functions found in BioConductor packages (limma and marray) to correct for dye biases and spatial artifacts. Goulphar provides a wide range of optional and customizable filters for excluding incorrect signals during the pre-processing step. It displays informative output plots, enabling the user to monitor the normalization process, and helps adapt the normalization method appropriately to the data. All these analyses and graphical outputs are presented in a single PDF report.

Conclusion

Goulphar provides simple, rapid access to the power of the R/BioConductor statistical analysis packages, with precise control and visualization of the results obtained. Complete documentation, examples and online forms for setting script parameters are available from http://transcriptome.ens.fr/goulphar/.
SNP-PHAGE – High throughput SNP discovery pipeline
Authors: Matukumalli Lakshmi K , Grefenstette John J , Hyten David L , Choi Ik-Young , Cregan Perry B , Van Tassell Curtis P
Published: October 2006

Background

Single nucleotide polymorphisms (SNPs) as defined here are single base sequence changes or short insertion/deletions between or within individuals of a given species. As a result of their abundance and the availability of high throughput analysis technologies SNP markers have begun to replace other traditional markers such as restriction fragment length polymorphisms (RFLPs), amplified fragment length polymorphisms (AFLPs) and simple sequence repeats (SSRs or microsatellite) markers for fine mapping and association studies in several species. For SNP discovery from chromatogram data, several bioinformatics programs have to be combined to generate an analysis pipeline. Results have to be stored in a relational database to facilitate interrogation through queries or to generate data for further analyses such as determination of linkage disequilibrium and identification of common haplotypes. Although these tasks are routinely performed by several groups, an integrated open source SNP discovery pipeline that can be easily adapted by new groups interested in SNP marker development is currently unavailable.

Results

We developed SNP-PHAGE (SNPdiscoveryPipeline with additional features for identification of common haplotypes within a sequence tagged site (HaplotypeAnalysis) andGenBank (-dbSNP) submissions. This tool was applied for analyzing sequence traces from diverse soybean genotypes to discover over 10,000 SNPs. This package was developed on UNIX/Linux platform, written in Perl and uses a MySQL database. Scripts to generate a user-friendly web interface are also provided with common queries for preliminary data analysis. A machine learning tool developed by this group for increasing the efficiency of SNP discovery is integrated as a part of this package as an optional feature. The SNP-PHAGE package is being made available open source athttp://bfgl.anri.barc.usda.gov/ML/snp-phage/.

Conclusion

SNP-PHAGE provides a bioinformatics solution for high throughput SNP discovery, identification of common haplotypes within an amplicon, and GenBank (dbSNP) submissions. SNP selection and visualization are aided through a user-friendly web interface. This tool is useful for analyzing sequence tagged sites (STSs) of genomic sequences, and this software can serve as a starting point for groups interested in developing SNP markers.
Evaluating different methods of microarray data normalization
Authors: Fujita André , Sato João Ricardo , Rodrigues Leonardo de Oliveira , Ferreira Carlos Eduardo , Sogayar Mari Cleide
Published: October 2006

Background

With the development of DNA hybridization microarray technologies, nowadays it is possible to simultaneously assess the expression levels of thousands to tens of thousands of genes. Quantitative comparison of microarrays uncovers distinct patterns of gene expression, which define different cellular phenotypes or cellular responses to drugs. Due to technical biases, normalization of the intensity levels is a pre-requisite to performing further statistical analyses. Therefore, choosing a suitable approach for normalization can be critical, deserving judicious consideration.

Results

Here, we considered three commonly used normalization approaches, namely: Loess, Splines and Wavelets, and two non-parametric regression methods, which have yet to be used for normalization, namely, the Kernel smoothing and Support Vector Regression. The results obtained were compared using artificial microarray data and benchmark studies. The results indicate that the Support Vector Regression is the most robust to outliers and that Kernel is the worst normalization technique, while no practical differences were observed between Loess, Splines and Wavelets.

Conclusion

In face of our results, the Support Vector Regression is favored for microarray normalization due to its superiority when compared to the other methods for its robustness in estimating the normalization curve.
Analyses of carnivore microsatellites and their intimate association with tRNA-derived SINEs
Authors: López-Giráldez Francesc , Andrés Olga , Domingo-Roura Xavier , Bosch Montserrat
Published: October 2006

Background

The popularity of microsatellites has greatly increased in the last decade on account of their many applications. However, little is currently understood about the factors that influence their genesis and distribution among and within species genomes. In this work, we analyzed carnivore microsatellite clones from GenBank to study their association with interspersed repeats and elucidate the role of the latter in microsatellite genesis and distribution.

Results

We constructed a comprehensive carnivore microsatellite database comprising 1236 clones from GenBank. Thirty-three species of 11 out of 12 carnivore families were represented, although two distantly related species, the domestic dog and cat, were clearly overrepresented. Of these clones, 330 contained tRNALys-derived SINEs and 357 contained other interspersed repeats. Our rough estimates of tRNA SINE copies per haploid genome were much higher than published ones. Our results also revealed a distinct juxtaposition of AG and A-rich repeats and tRNALys-derived SINEs suggesting their coevolution. Both microsatellites arose repeatedly in two regions of the insterspersed repeat. Moreover, microsatellites associated with tRNALys-derived SINEs showed the highest complexity and less potential instability.

Conclusion

Our results suggest that tRNALys-derived SINEs are a significant source for microsatellite generation in carnivores, especially for AG and A-rich repeat motifs. These observations indicate two modes of microsatellite generation: the expansion and variation of pre-existing tandem repeats and the conversion of sequences with high cryptic simplicity into a repeat array; mechanisms which are not specific to tRNALys-derived SINEs. Microsatellite and interspersed repeat coevolution could also explain different distribution of repeat types among and within species genomes.

Finally, due to their higher complexity and lower potential informative content of microsatellites associated with tRNALys-derived SINEs, we recommend avoiding their use as genetic markers.
Molecular characterization of a DNA fragment harboring the replicon of pBMB165 from Bacillus thuringiensis subsp. tenebrionis
Authors: Huang Junyan , Guo Suxia , Mahillon Jacques , Van der Auwera Géraldine A , Wang Li , Han Dongmei , Yu Ziniu , Sun Ming
Published: October 2006

Background

Bacillus thuringiensis belongs to the Bacillus cereus sensu lato group of Gram-positive and spore-forming bacteria. Most isolates of B. thuringiensis can bear many endogenous plasmids, and the number and size of these plasmids can vary widely among strains or subspecies. As far as we know, the replicon of the plasmid pBMB165 is the first instance of a plasmid replicon being isolated from subsp. tenebrionis and characterized.

Results

A 20 kb DNA fragment containing a plasmid replicon was isolated from B. thuringiensis subsp. tenebrionis YBT-1765 and characterized. By Southern blot analysis, this replicon region was determined to be located on pBMB165, the largest detected plasmid (about 82 kb) of strain YBT-1765. Deletion analysis revealed that a replication initiation protein (Rep165), an origin of replication (ori165) and an iteron region were required for replication. In addition, two overlapping ORFs (orf6 and orf10) were found to be involved in stability control of plasmid. Sequence comparison showed that the replicon of pBMB165 was homologous to the pAMβ1 family replicons, indicating that the pBMB165 replicon belongs to this family. The presence of five transposable elements or remnants thereof in close proximity to and within the replicon control region led us to speculate that genetic exchange and recombination are potentially responsible for the divergence among the replicons of this plasmid family.

Conclusion

The replication and stability features of the pBMB165 from B. thuringiensis subsp. tenebrionis YBT-1765 were identified. Of particular interest is the homology and divergence shared between the pBMB165 replicon and other pAMβ1 family replicons.
Relative risk for cardiovascular atherosclerotic events after smoking cessation: 6–9 years excess risk in individuals with familial hypercholesterolemia
Authors: Kramer Anneke , Jansen Angelique CM , van Aalst-Cohen Emily S , Tanck Michael WT , Kastelein John JP , Zwinderman Aeilko H
Published: October 2006

Background

Smoking history is often di- or trichotomized into for example "never, ever or current smoking". However, smoking must be treated as a time-dependent covariate when lifetime data is available. In particular, individuals do not smoke at birth, there is usually a wide variation with respect to smoking history, and smoking cessation must also be considered.

Methods

Therefore we analyzed smoking as a time-dependent risk factor for cardiovascular atherosclerotic events in a cohort of 2400 individuals with familial hypercholesterolemia who were followed from birth until 2004. Excess risk after smoking-cessation was modelled in a Cox regression model with linear and exponential decaying trends. The model with the highest likelihood value was used to estimate the decay of the excess risk of smoking.

Results

Atherosclerotic events were observed in 779 patients with familial hypercholesterolemia and 1569 individuals had a smoking history. In the model with the highest likelihood value the risk reduction of smoking after cessation follows a linear pattern with time and it appears to take 6 to 9 years before the excess risk is reduced to zero. The risk of atherosclerotic events due to smoking was estimated as 2.1 (95% confidence interval 1.5; 2.9).

Conclusion

It was concluded that excess risk due to smoking declined linearly after cessation in at least six to nine years.
Gaining insight into the Clinical Practice Guideline development processes: qualitative study in a workshop to implement the GRADE proposal in Spain
Authors: Calderón Carlos , Rotaeche Rafael , Etxebarria Arritxu , Marzo Mercé , Rico Rosa , Barandiaran Marta
Published: October 2006

Background

The GRADE method represents a new approach to grading the quality of evidence and strength of recommendations in the preparation of Clinical Practice Guidelines (CPG). In the context of a pilot study to assess the implementability of the system in Spain, we considered it relevant to gain an insight into the significance of the perceptions and attitudes expressed by the actual experts participating in the system try-out.

Methods

Qualitative research with an ethnographic approach, through non-participant observation and focus groups within the context of a consensus workshop in which 19 CPG experts participated to evaluate the GRADE proposal using 12 evidence tables taken from hypertension, asthma and arthritis CPGs. The interventions were recorded, under a guarantee of confidentiality. The transcriptions and field notes were analyzed, based on a sociological discourse analysis model, and the provisional findings were re-sent to participants in order to improve their validity.

Results

1) Certain problems over procedure and terminology hindered the acceptance of this new method as a common reference system for the preparation of CPGs. 2). A greater closeness to clinical practice was accompanied by concerns over value judgments and subjectivity, with a demand for greater explicitness in the consensus process. 3). The type of "evidence" on which the guidelines are based, how and by whom the evidence is prepared, and what the role of the different actors should be, all constitute unresolved concerns in the CPG preparation and implementation processes. 4). The grading process is not neutral: professional background, prior experience and the degree of leadership all condition the participants' input and interactions.

Conclusion

The findings obtained allow the quantitative evaluation to be better interpreted and, in turn, go beyond the particularities of the GRADE method. Adaptation to the complexities of clinical practice, the need for carefully designed multi-disciplinary work and the reflexivity present in the CPG preparation process, all represent lines of debate that are necessary to improve the CPG quality in the Spanish health care sector.
On Blending Practice and Research
Authors: Kellogg Scott , Kreek Mary Jeanne
Published: October 2006

There has been a growing interest in the substance abuse treatment field in bringing together the treatment and research communities. While dialogues about logistical and philosophical issues are important, the development of shared core concepts could potentially be quite helpful in facilitating communication and creating common treatment and research goals. It is the contention of this paper that all psychosocial and, potentially, pharmacological treatments ideally address, in part or in full, three aspects of the self-the capacity to regulate emotional and behavioral expression, the ability to engage in future-oriented, goal-directed behavior, and the development of nonaddict and/or recovery-oriented identities. Examples from the research and treatment literature are provided.
Racial/Ethnic Differences in the Protective Effects of Self-Management Skills on Adolescent Substance Use
Authors: Griffin Kenneth W. , Botvin Gilbert J. , Scheier Lawrence M.
Published: October 2006

A variety of cognitive and behavioral self-management skills have been posited as protective in terms of adolescent substance use. This study examined whether these skills measured in the 7th grade served a protective function in 9th grade substance use across ethnically diverse samples of adolescents. Participants consisted of Black (n = 461) and Hispanic (n = 320) urban youth and White suburban youth (n = 757). Structural equation modeling indicated that a second order Self-Management Skills latent factor consisting of first order latent factors of Decision-Making, Self-Regulation, and Self-Reinforcement skills was protective for adolescent substance use across racial/ethnic subgroups. However, Self-Management Skills were more strongly protective for suburban White youth and less protective for urban minority youth. These findings are consistent with previous research showing that predictive power of risk and protective factors derived from psychosocial theories varies widely across racial/ethnic subgroups of youth and is weaker among racial/ethnic minority youth compared to White youth. An important next step is to broaden the focus of etiology research from individual-level determinants to studying adolescent substance use behavior in the context of the cultural background and primary social settings of young people, such as family, school, and community environments.
Initiating Tobacco Curricula in Dental Hygiene Education
Authors: Boyd Linda D. , Fun Kay , Madden Theresa E.
Published: October 2006

Two hours of tobacco instructions were incorporated into the baccalaureate dental hygiene curricula in a university in the Northwestern United States. Prior to graduation, all senior students were invited to complete anonymously a questionnaire surveying attitudes and clinical skills in providing tobacco services to their clinic patients. Twenty students (67%) responded but no data was collected on the non-respondents. Eighteen (90%) reported practicing some of the “5 A's,” and a few reported sustained adherence to all “5 A's.” Moderately successful clinical outcomes parallelled students’ moderate self-rating of their knowledge/skills. When asked to identify barriers to sustained and ongoing full adherence, most students cited “patient resistance/disinterest,” and their own “lack of knowledge or confidence in the skills.” Our preliminary findings suggest that additional content and training time may be required for dental hygiene graduates to feel highly confident and knowledgeable, and for them to sustain comprehensive tobacco services once in practice.
Serum Levels of Specific Glucuronidated Androgen Metabolites Predict BMD and Prostate Volume in Elderly Men
Authors: Vandenput Liesbeth , Labrie Fernand , Mellström Dan , Swanson Charlotte , Knutsson Thomas , Peeker Ralph , Ljunggren Östen , Orwoll Eric , Eriksson Anna L , Damber Jan-Erik , Ohlsson Claes
Published: October 2006

Androgens are important regulators of bone and prostate health in elderly men. The role of serum levels of glucuronidated androgen metabolites as predictors of BMD and prostate volume in men is unclear. We show that specific glucuronidated androgen metabolites predict BMD and prostate volume in elderly men.

Introduction: Androgens are important regulators of bone and prostate health in elderly men. Local synthesis and degradation of androgens are likely to be important parameters of biological action of androgens in androgen-responsive tissues. The aim of this study was to determine the role of serum levels of glucuronidated androgen metabolites as predictors of BMD and prostate volume in elderly men.

Materials and Methods: A subsample of the population-based Swedish part of the MrOS study (n = 631, average age = 75.9 years) was investigated. Bone parameters were measured using DXA. Serum levels of total testosterone (T) and dihydrotestosterone (DHT) were measured by gas chromatography/mass spectroscopy (GC-MS); androstane-3α,17β-diol-3glucuronide (3G) and androstane-3α,17β-diol-17glucuronide (17G) were measured by liquid chromatography/mass spectroscopy. Prostate volume (n = 159) was measured by transrectal ultrasound.

Results: The general pattern is that two of the glucuronidated androgen metabolites, namely 17G and 3G, are stronger positive predictors of BMD than the bioactive androgens (T and DHT). In addition, 17G is a clear positive predictor of prostate volume, explaining 4.5% of the variance in prostate volume, whereas the bioactive androgens do not display any association with prostate volume.

Conclusions: Serum levels of specific glucuronidated androgen metabolites predict BMD and prostate volume in elderly men. Future studies should determine if the glucuronidated androgen metabolites also reflect other biological correlates of androgenic activity, including prostate cancer, and if low levels might be a marker of general androgen deficiency in men.
A Longitudinal Study of the Effects of Ecological Interface Design on Skill Acquisition
Authors: Christoffersen Klaus , Hunter Christopher N. , Vicente Kim J.
Published: October 2006

Results from evaluations of interface design concepts conducted over short durations may not generalize to longer time spans. In an attempt to address this issue, this paper presents a longitudinal study of the effect of interface design on skill acquisition in which participants' quasi-dally performance was observed over an unprecedented period of six months. The research was conducted in the context of DURESS II, a real-time, interactive thermal-hydraulic process control simulation that was designed to be representative of industrial systems. The performance of two interfaces was compared, one containing physical and functional (P + F) system representations based on the principles of the ecological interface design framework, and a more traditional interface based solely on a physical (P) representation. Participants were required to perform several control tasks, including start-up, tuning, shutdown, and fault management. The results indicate that the P interface led to significantly less-consistent performance than did the P + F interface; with the former, participants occasionally took up to 2 times longer to complete the required tasks, even after 5.5 months of daily practice. There was very little difference in average performance between the two groups. These results have important implications for designing interfaces that lead to efficient performance under normal operating conditions.
Age-Related Differences in Perceptual Learning
Authors: Gilbert D. Kristen , Rogers Wendy A.
Published: October 2006

The present study investigated age-related differences in perceptual learning. We assessed performance and learning on a semantic category visual search task. We investigated whether prepractice was beneficial for general learning and for automatic attention response development. In terms of general learning, prepractice was beneficial, especially for older adults; however, prepractice did not benefit automatic attention response development. The implications of these results for training purposes are discussed.
Identifying Factors of Comfort and Discomfort in Sitting
Authors: Zhang Luian , Helander Martin G. , Drury Colin G.
Published: October 2006

We conducted a classification analysis to identify factors associated with sitting comfort and discomfort. The objective was to investigate the possible multidimensional nature of comfort and discomfort. Descriptors of feelings of comfort and discomfort were solicited from office workers and validated in a questionnaire study. From this study, 43 descriptors emerged. The 42 participants rated the similarity of all 903 pairs of descriptors, and we subjected the resulting similarity matrix to multidimensional scaling, factor analysis, and cluster analysis. Two main factors emerged, which were interpreted as comfort and discomfort. Based on these findings, we postulate a hypothetical model for perception of comfort and discomfort. Comfort and discomfort need to be treated as different and complementary entities in ergonomic investigations.
Decision Support and Information Search in a Complex Environment: Evidence from Archival Data in Auditing
Authors: Salterio Steven
Published: October 2006

This research studied the situation assessment process in a complex decision support environment. I studied auditors at the central research unit of a large public accounting firm as they performed information search tasks as part of the situation assessment process. In particular, the research examined whether expertise-based information search findings in laboratory studies generalized to analyzing ill-structured problems and the related searching of complex databases that contained prior cases. I employed archival data to study the auditors at two points: when they were relative novices at situation assessment and five months later, when they were relative experts. Prior laboratory studies of information search provided the basis for advancing four hypotheses about how information search would change as auditors gained experience in the natural decision support environment. Employing a within-subjects design, I tested the four hypotheses. The results supported the generalization of the laboratory findings to the field setting. I discuss the implications of these findings for naturalistic decision support applications and the management of databases containing prior cases as aids to situation assessment.
Effects of Group Discussion on Acquisition of Complex Skills
Authors: Prislin Radmila , Jordan Jeffrey A. , Worchel Stephen , Semmer Franziska Tschan , Shebilske Wayne L.
Published: October 2006

The study tested whether group discussion facilitates acquisition of Space Fortress (SF), a complex skills task, and if so, what aspects of discussion are responsible for the effect. The experimental group participants who engaged in unguided group discussion about SF performed the task significantly better than did controls. Factor analysis of task-related discussion yielded three general discussion orientations: advice, social comparison, and motivation. The latter two orientations interacted to predict the final performance: Social comparison contributed to performance at the low and average but not at the high levels of the motivation factor. An additional analysis of the advice or information exchange orientation yielded two dimensions recognized as strategy and cognitive overload. They also interacted to predict the final performance: Discussion of strategy was beneficial to performance, but only at the low level of cognitive overload. Implications for the organization of training protocols are discussed.
Television Captions for Hearing-Impaired People: A Study of Key Factors that Affect Reading Performance
Authors: Thorn Frank , Thorn Sondra
Published: October 2006

Closed captions are broadcast with television programs for special-needs viewers such as hearing-impaired people. We examined how caption presentation rate, small amounts of induced dioptric blur, and English learned as a second language affect the reading performance of good readers. Thirty-two college graduates with normal hearing and vision, half of whom learned English as a second language, read television captions that consisted of white capital letters equivalent in size to 20/92 Snellen letters on a black background. Text was presented at rates of 55, 120, and 216 words/min. Lenses of 0, 0.5, 1.0, or 1.5 diopters (D) were worn over the person's best refractive correction. The fastest text rate and small amounts of blur significantly disrupted reading performance. People who learned English as a second language were hindered more by presentation rate than by dioptric blur. Surprisingly, people with refractive errors (even though they were optically corrected) were hindered less by induced blur than were people with normally clear vision.