bluuebunny/crossref_metadata_2025_split huggingface dataset:
Genetic affinities among the lower castes and tribal groups of India: inference from Y chromosome and mitochondrial DNA
Authors: Thanseem Ismail , Thangaraj Kumarasamy , Chaubey Gyaneshwer , Singh Vijay Kumar , Bhaskar Lakkakula VKS , Reddy B Mohan , Reddy Alla G , Singh Lalji 
Published: September 2006

AbstractBackgroundIndia is a country with enormous social and cultural diversity due to its positioning on the crossroads of many historic and pre-historic human migrations. The hierarchical caste system in the Hindu society dominates the social structure of the Indian populations. The origin of the caste system in India is a matter of debate with many linguists and anthropologists suggesting that it began with the arrival of Indo-European speakers from Central Asia about 3500 years ago. Previous genetic studies based on Indian populations failed to achieve a consensus in this regard. We analysed the Y-chromosome and mitochondrial DNA of three tribal populations of southern India, compared the results with available data from the Indian subcontinent and tried to reconstruct the evolutionary history of Indian caste and tribal populations.ResultsNo significant difference was observed in the mitochondrial DNA between Indian tribal and caste populations, except for the presence of a higher frequency of west Eurasian-specific haplogroups in the higher castes, mostly in the north western part of India. On the other hand, the study of the Indian Y lineages revealed distinct distribution patterns among caste and tribal populations. The paternal lineages of Indian lower castes showed significantly closer affinity to the tribal populations than to the upper castes. The frequencies of deep-rooted Y haplogroups such as M89, M52, and M95 were higher in the lower castes and tribes, compared to the upper castes.ConclusionThe present study suggests that the vast majority (>98%) of the Indian maternal gene pool, consisting of Indio-European and Dravidian speakers, is genetically more or less uniform. Invasions after the late Pleistocene settlement might have been mostly male-mediated. However, Y-SNP data provides compelling genetic evidence for a tribal origin of the lower caste populations in the subcontinent. Lower caste groups might have originated with the hierarchical divisions that arose within the tribal groups with the spread of Neolithic agriculturalists, much earlier than the arrival of Aryan speakers. The Indo-Europeans established themselves as upper castes among this already developed caste-like class structure within the tribes.
The use of comparative genomic hybridization to characterize genome dynamics and diversity among the serotypes of Shigella
Authors: Peng Junping , Zhang Xiaobing , Yang Jian , Wang Jing , Yang E , Bin Wen , Wei Candong , Sun Meisheng , Jin Qi 
Published: September 2006

Abstract

Background
Compelling evidence indicates that Shigella species, the etiologic agents of bacillary dysentery, as well as enteroinvasive Escherichia coli, are derived from multiple origins of Escherichia coli and form a single pathovar. To further understand the genome diversity and virulence evolution of Shigella, comparative genomic hybridization microarray analysis was employed to compare the gene content of E. coli K-12 with those of 43 Shigella strains from all lineages.

Results
For the 43 strains subjected to CGH microarray analyses, the common backbone of the Shigella genome was estimated to contain more than 1,900 open reading frames (ORFs), with a mean number of 726 undetectable ORFs. The mosaic distribution of absent regions indicated that insertions and/or deletions have led to the highly diversified genomes of pathogenic strains.

Conclusion
These results support the hypothesis that by gain and loss of functions, Shigella species became successful human pathogens through convergent evolution from diverse genomic backgrounds. Moreover, we also found many specific differences between different lineages, providing a window into understanding bacterial speciation and taxonomic relationships.
Patterns of clinical presentation of adult coeliac disease in a rural setting
Authors: Jones Sián , D'Souza Charles , Haboubi Nadim Y 
Published: September 2006

Abstract

Background
In recent years there has been increasing recognition that the pattern of presentation of coeliac disease may be changing. The classic sprue syndrome with diarrhoea and weight loss may be less common than the more subtle presentations of coeliac disease such as an isolated iron deficiency anaemia. As a result, the diagnosis of this treatable condition is often delayed or missed. Recent serologic screening tests allow non-invasive screening to identify most patients with the disease and can be applied in patients with even subtle symptoms indicative of coeliac disease. Both benign and malignant complications of coeliac disease can be avoided by early diagnosis and a strict compliance with a gluten free diet.

Aim
The aim of this study is to evaluate the trends in clinical presentation of patients diagnosed with adult coeliac disease. In addition, we studied the biochemical and serological features and the prevalence of associated conditions in patients with adult coeliac disease.

Methods
This is an observational, retrospective, cross-sectional review of the medical notes of 32 adult patients attending the specialist coeliac clinic in a district general hospital.

Results
Anaemia was the most common mode of presentation accounting for 66% of patients. Less than half of the patients had any of the classical symptoms of coeliac disease and 25% had none of the classical symptoms at presentation. Anti-gliadin antibodies, anti-endomysial antibody and anti-tissue transglutaminase showed 75%, 68% and 90% sensitivity respectively. In combination, serology results were 100% sensitive as screening tests for adult coeliac disease. Fifty nine percent patients had either osteoporosis or osteopenia. There were no malignant complications observed during the follow up of our patients.

Conclusion
Most adults with coeliac disease have a sub clinical form of the disease and iron deficiency anaemia may be its sole presenting symptom. Only a minority of adult coeliac disease patients present with classical mal-absorption symptoms of diarrhoea and weight loss. Patients with atypical form of disease often present initially to hospital specialists other than a gastro-enterologist. An awareness of the broad spectrum of presentations of adult coeliac disease, among doctors both in primary care and by the various hospital specialists in secondary care, is necessary to avoid delays in diagnosis. It is important to include serological screening tests for coeliac disease systematically in the evaluation of adult patients with unexplained iron deficiency anaemia or unexplained gastro-intestinal symptoms and in those who are considered to be at increased risk for coeliac disease.
Temperature sensitive influenza A virus genome replication results from low thermal stability of polymerase-cRNA complexes
Authors: Dalton Rosa M , Mullin Anne E , Amorim Maria Joao , Medcalf Elizabeth , Tiley Laurence S , Digard Paul 
Published: September 2006

Abstract

Background
The RNA-dependent RNA polymerase of Influenza A virus is a determinant of viral pathogenicity and host range that is responsible for transcribing and replicating the negative sense segmented viral genome (vRNA). Transcription produces capped and polyadenylated mRNAs whereas genome replication involves the synthesis of an alternative plus-sense transcript (cRNA) with unmodified termini that is copied back to vRNA. Viral mRNA transcription predominates at early stages of viral infection, while later, negative sense genome replication is favoured. However, the "switch" that regulates the transition from transcription to replication is poorly understood.

Results
We show that temperature strongly affects the balance between plus and minus-sense RNA synthesis with high temperature causing a large decrease in vRNA accumulation, a moderate decrease in cRNA levels but (depending on genome segment) either increased or unchanged levels of mRNA. We found no evidence implicating cellular heat shock protein activity in this effect despite the known association of hsp70 and hsp90 with viral polymerase components. Temperature-shift experiments indicated that polymerase synthesised at 41°C maintained transcriptional activity even though genome replication failed. Reduced polymerase association with viral RNA was seen in vivo and in confirmation of this, in vitro binding assays showed that temperature increased the rate of dissociation of polymerase from both positive and negative sense promoters. However, the interaction of polymerase with the cRNA promoter was particularly heat labile, showing rapid dissociation even at 37°C. This suggested that vRNA synthesis fails at elevated temperatures because the polymerase does not bind the promoter. In support of this hypothesis, a mutant cRNA promoter with vRNA-like sequence elements supported vRNA synthesis at higher temperatures than the wild-type promoter.

Conclusion
The differential stability of negative and positive sense polymerase-promoter complexes explains why high temperature favours transcription over replication and has implications for the control of viral RNA synthesis at physiological temperatures. Furthermore, given the different body temperatures of birds and man, these finding suggest molecular hypotheses for how polymerase function may affect host range.
Lipids in dendritic cell biology: messengers, effectors, and antigens
Authors: Thurnher Martin 
Published: September 2006

AbstractDendritic cells (DC) are the most professional APC, which induce and coordinate immune responses. The principal task of DC is T cell activation, although DC also interact with and regulate other cell types. The present review serves to illustrate the increasing evidence that lipids play an important role in DC biology. In addition to being fuel stores and structural components of cellular membranes such as in other cell types, lipids act as second messengers and as effectors throughout all steps of DC differentiation and regulate important DC functions. The recent finding that DC synthesize lipid antigens in response to bacterial stimulation and induce antibacterial, CD1-restricted T cells through antigenic mimicry further emphasizes the important role of lipids and DC at the blurring boundaries of innate and adaptive immunity.
An analysis of the Revised Olweus Bully/Victim Questionnaire using the Rasch measurement model
Authors: Kyriakides Leonidas , Kaloyirou Chrystalla , Lindsay Geoff 
Published: September 2006

Background. Bullying is a problem in schools in many countries. There would be a benefit in the availability of a psychometrically sound instrument for its measurement, for use by teachers and researchers. The Olweus Bully/Victim Questionnaire has been used in a number of studies but comprehensive evidence on its validity is not available.Aims. To examine the conceptual design, construct validity and reliability of the Revised Olweus Bully/Victim Questionnaire (OBVQ) and to provide further evidence on the prevalence of different forms of bullying behaviour.Sample. All 335 pupils (160 [47.8%] girls; 175 [52.2%]) boys, mean age 11.9 years [range 11.2–12.8 years]), in 21 classes of a stratified sample of 7 Greek Cypriot primary schools.Method. The OBVQ was administered to the sample. Separate scales were created comprising (a) the items of the questionnaire concerning the extent to which pupils are being victimized; and (b) those concerning the extent to which pupils express bullying behaviour. Using the Rasch model, both scales were analysed for reliability, fit to the model, meaning, and validity. Both scales were also analysed separately for each of two sample groups (i.e. boys and girls) to test their invariance.Results. Analysis of the data revealed that the instrument has satisfactory psychometric properties; namely, construct validity and reliability. The conceptual design of the instrument was also confirmed. The analysis leads also to suggestions for improving the targeting of items against student measures. Support was also provided for the relative prevalence of verbal, indirect and physical bullying. As in other countries, Cypriot boys used and experienced more bullying than girls, and boys used more physical and less indirect forms of bullying than girls.Conclusions. The OBVQ is a psychometrically sound instrument that measures two separate aspects of bullying, and whose use is supported for international studies of bullying in different countries. However, improvements to the questionnaire were also identified to provide increased usefulness to teachers tackling this significant problem facing schools in many countries.
Personal bests (PBs): A proposed multidimensional model and empirical analysis
Authors: Martin Andrew J. 
Published: September 2006

Background. This study seeks to identify the cornerstones of personal bests (PBs) in the educational setting.Aims. The study proposes a multidimensional PB model in which students are most likely to attain PBs on tasks/goals that are (1) specific, (2) challenging, (3) competitively self‐referenced, and (4) self‐improvement based.Sample. The study draws upon data from 1,016 students from 5 Australian high schools.Methods. The hypothesized 4‐factor structure, its invariance across gender and year‐level, and the predictive utility of PBs are tested using confirmatory factor analysis and structural equation models with particular focus on the contribution of a higher‐order PB construct to measures of persistence, class participation, educational aspirations, and enjoyment of school. The fundamental dimensions of the model are further tested using multidimensional scaling.Results. The 4‐factor structure fit the data well and significantly predicted persistence, class participation, educational aspirations, and enjoyment of school. The multidimensional scaling indicates that the 4 component factors can be defined in terms of the dual extent to which they reflect a clear goal focus and a self‐improvement focus.Conclusion. Discussion centres on a proposed ‘Quadriploar PB Model’ emanating from the data analysis and strategies educators can use to facilitate PBs in the classroom.
What goes well with physics? Measuring and altering the image of science
Authors: Kessels Ursula , Rau Melanie , Hannover Bettina 
Published: September 2006

Background. In view of the shortage of students majoring in science, we examined the image of physics in terms of students' implicit, automatic associations with physics.Aims. To describe the specific image of physics that might alienate students (difficulty, masculinity, heteronomy) and test an intervention for altering the image.Samples. In Study 1 the sample consisted of 63 school students (11th grade) and in Study 2 the sample consisted of 71 undergraduates.Methods. Study 1 measured participants' implicit associations between physics (relative to English) and the image dimensions of difficulty, masculinity and heteronomy, implicit attitudes towards and identification with physics using latency data (Implicit Association Test; IAT) and explicit attitudes using a questionnaire. Study 2 was an experimental treatment that required reading a text (treatment group) that emphasized the importance of discourse and creativity for science versus a school textbook for physics (control group). Dependent variables: implicit attitudes (IAT).Results. Students in Study 1 associated physics (relative to English) more easily with words referring to difficulty (than to ease), to males (than to females), to heteronomy (than to self‐realization), to unpleasantness (relative to pleasant words) and to others (relative to words referring to self). The three image aspects of difficulty, masculinity and heteronomy predicted explicit attitudes. Participants in the treatment group in Study 2 showed a significant reduction of the IAT effects compared to the control group.Conclusions. The findings indicate that students' negative explicit attitudes towards physics coincide with negative implicit associations about physics. An intervention addressing the alteration of implicit associations proved to be fruitful. Implications for science education are discussed.
Teachers' perceptions of remediation possibilities of Dutch students in special education
Authors: Bakker Joep T. A. , Bosman Anna M. T. 
Published: September 2006

Background. Research suggests that referral practices of teachers in regular education are not only affected by the level of learning difficulties but also by student behaviour and the level of students' parental involvement in education. It was hypothesized that teachers maintain a notion of the ‘ideal’ student, who has relatively good academic skills, is well behaved and has highly involved parents.Aims. The main question of this study was whether special‐education teachers' perceptions regarding remediation possibilities are similarly affected by student behaviour and the level of students' parental involvement.Sample. Nineteen experienced Dutch school teachers in special education each evaluated four students: two with relatively high and two with relatively low academic performance.Methods. Three questionnaires to assess learning difficulties, behavioural problems and the level of parental involvement were developed.Results. Teachers' perceptions of remediation possibilities were related to the severity of the learning difficulties and academic skill. Academic skill, in turn, was strongly related to the perception of the children's behavioural problems and parental involvement, which, in turn, links the perception of remediation possibilities indirectly to children's behavioural problems and parental involvement.Conclusions. Special education teachers may also hold an image of the ‘ideal’ student. Students with high academic achievement levels are perceived as having fewer behavioural problems and more highly involved parents than students with low academic achievement levels. Whether this is due to justified or unjustified teachers' perceptions is a matter for future research. What is important is that stereotyping of students (justly or not) poses a serious problem for the Dutch reintegration policy.
Profiles of children with specific reading comprehension difficulties
Authors: Cain Kate , Oakhill Jane 
Published: September 2006

Background. Children with fluent and accurate word reading in the presence of poor text comprehension are impaired on a wide range of reading‐related tasks.Aims. This study investigated the consistency of skill impairment in a sample of poor comprehenders to identify any fundamental skill weakness that (i) might be associated with poor text comprehension, and (ii) might lead to depressed reading development. An additional aim was to determine whether reading comprehension difficulties are associated with more general educational difficulties.Sample. Twenty‐three poor comprehenders and 23 good comprehenders with age‐appropriate word reading accuracy were assessed when aged 8 years. Concurrent reading and language performance and reading, educational attainment and reasoning skills 3 years later are reported.Methods. The following skills were assessed when aged 8 years: word reading, text comprehension, vocabulary, syntax, cognitive ability, working memory, comprehension subskills. Listening comprehension, SAT scores and reasoning scores at 11 years are also reported.Results. There was no evidence for any fundamental skill weaknesses in the population of poor comprehenders at Time 1. However, poor vocabulary skills led to impaired growth in word reading ability and poor general cognitive ability led to impaired growth in comprehension. Poor comprehenders obtained lower SAT scores than did the good comprehenders at 11 years.Conclusions. These findings indicate that a single underlying source of poor comprehension is unlikely. Poor comprehenders are at risk of generally poor educational attainment, although weak verbal or cognitive skills appear to affect the reading development of poor comprehenders in different ways.
Assessment matters: Issues in the measurement of reading comprehension
Authors: Cain Kate , Oakhill Jane 
Published: September 2006

Background. The Neale Analysis of Reading Ability (NARA; Neale, 1997) is a widely used assessment of reading comprehension and word reading accuracy. Spooner, Baddeley, and Gathercole (2004) questioned the suitability of the NARA for identifying children with specific reading comprehension deficits.Aims and methods. An evaluation of the NARA measurement of word reading and reading comprehension level was undertaken in relation to models of reading ability. Appropriate control measures were considered. The strengths and weaknesses of different forms of reading comprehension were also evaluated.Results. Previous research into reading comprehension difficulties using the NARA has adopted satisfactory control measures in relation to word reading ability. There are limitations associated with all the considered forms of reading comprehension assessment.Conclusions. If administered and interpreted appropriately, the NARA is an effective instrument for researchers and practitioners who need to assess both word reading accuracy and reading comprehension and to identify children with a dissociation between these two aspects of reading.
Self‐construal and social comparison effects
Authors: Cheng Rebecca Wing‐yi , Lam Shui‐fong 
Published: September 2006

Background. Social comparison research usually demonstrates that students will have higher self‐evaluation in downward comparison but lower self‐evaluation in upward comparison. However, the existence of this contrast effect may depend on people's self‐construal. The contrast effect may exist only for people with independent self‐construal. For people with interdependent self‐construal, the contrast effect may be attenuated.Aim. The study investigated the role of self‐construal as a moderator of the social comparison effects in authentic classrooms.Sample. The participants were 96 Chinese seventh‐grade students (41 male, 51 female and 4 unreported) from a secondary school in Hong Kong.Method. The experiment employed a 2 × 2 between‐subjects design based on 2 levels of self‐construal (independent, interdependent) and 2 levels of comparison standard (upward comparison, downward comparison). The dependent variable was students' self‐evaluation.Results. A two‐way ANOVA indicated a significant interaction between self‐construal and comparison standard on self‐evaluation. When the students' independent self‐construal was activated, they reported higher self‐evaluation in downward comparison but lower self‐evaluation in upward comparison. However, such a contrast effect was attenuated when the students' interdependent self‐construal was activated. They reported high self‐evaluation in both upward and downward comparisons.Conclusions. The outcome of social comparison depends on whether independent or interdependent self‐construal is salient in the classroom.