bluuebunny/crossref_metadata_2025 huggingface dataset:
Historical Experiences, Collective Memory, and Willingness to Fight for One’s Country: Comments on Paez et al. (2008)
Authors: Gibson Stephen , Noret Nathalie
Published: April 2010

This article considers Paez et al.’s (2008) article “‘Remembering’ World War II and Willingness to Fight: Sociocultural Factors in the Social Representation of Historical Warfare Across 22 Societies.” Despite the importance of their focus on social representations of history and willingness to fight for one’s country, it is argued that Paez et al.’s article features a number of methodological flaws. Specifically, the way in which key variables (historical experience, collective memory, and willingness to fight for one’s country) are operationalized is especially problematic. The implications of these weaknesses for their conceptual conclusions are discussed briefly, as are the more general limitations of statistical analyses of survey data for addressing these issues.
Comparing Regional Cultures Within a Country: Lessons From Brazil
Authors: Hofstede Geert , Garibaldi de Hilal Adriana V. , Malvezzi Sigmar , Tanure Betania , Vinken Henk
Published: April 2010

In this joint article we test the common assumption that a measure of culture developed for the national level can also be used for comparing regions within a country. Three different research projects independently measured culture differences within the Federal Republic of Brazil, all three using a version of Hofstede’s Values Survey Module (VSM). The largest provided separate scores for all of Brazil’s 27 states, the next largest for 17 of the more populous states. Factor analyses of VSM item scores across states in both cases only very partly replicated Hofstede’s cross-national dimension structure; only Individualism versus Collectivism reappeared clearly. We attribute this lack of fit to a restriction of range of VSM item scores among states within a common Brazilian national culture. The item scores did show a cultural clustering of states that fairly closely followed the administrative division of the country into five regions. The culture profiles for these regions show remarkable differences between the Northeast with its Afro-Brazilian roots and the North with its native Indian roots. On the issue of comparing regional cultures, we found the VSM, based on global differences, too coarse a net for catching the finer cultural nuances between Brazilian states. Adding locally defined items would have made the studies more meaningful to Brazilians.
Guardians on Guardianship: Factors Affecting the Willingness to Supervise, the Ability to Detect Potential Offenders, and the Willingness to Intervene
Authors: Reynald Danielle M.
Published: April 2010

Within criminology, much attention has been given to the processes of offending and victimization, but comparatively few studies have focused on the processes underlying guardianship. The current study turns the spotlight toward the capable guardian as the critical actor within the crime event model with the power to prevent crime. This study interviews residential guardians to examine key factors that render them capable of disrupting opportunities for crime. Results reveal three critical dimensions of capable guardianship at micro-places: (1) the willingness to supervise, (2) the ability to detect potential offenders, and (3) the willingness to intervene when necessary.
“Voluntariness of Exposure”: Life in a Convict Station
Authors: Sawchuk Lawrence A. , Tripp Lianne , Mohan Michelle M.
Published: April 2010

Convict Stations were commonplace during the 19th century. Despite the fact that thousands of prisoners of the British Empire served out their sentences under deplorable conditions, scant information exists on the health of these men. Using Gibraltar’s Convict Station as a case study, a profile of life of the convicts is documented. An examination of the health profile of the prisoners for the period from 1860 to 1873 suggests that their overall health status was similar to that of the military, another transient group resident on the Rock. However, during the cholera epidemic of 1865, the health of the convicts was severely compromised with significantly higher attack and mortality rates. Factors responsible for the higher rates can be attributed to a cluster of vulnerabilities that were intrinsic to the convict way of life where exposure to a host of risk factors played out during a compressed period of time.
Labor Market Effects on Dropping Out of High School: Variation by Gender, Race, and Employment Status
Authors: McNeal Ralph B.
Published: April 2010

It is known from previous research that the likelihood of dropping out is affected by a number of individual traits, including, among others, socioeconomic status (SES), race/ethnicity, gender, and employment status. It is also known that dropping out is contingent on a variety of school characteristics. What is less known about is how dropping out and the work—dropping out relationship are affected by larger social contexts such as the local labor market area (LMA). This research asks three questions. First, to what degree does the work—dropping out relationship vary by SES? Second, to what degree does a larger social context, in this case LMAs, affect the likelihood of dropping out? Third, are LMA effects contingent on, or vary by, the student’s individual traits such as SES, gender, race/ethnicity, and employment status? Findings from a series of hierarchical regression models provide answers, at least in part, to these questions. First, the relationship between adolescent employment and dropping out is contingent on the student’s SES. Second, LMAs directly affect a student’s likelihood of dropping out. Third, LMA effects vary substantially by student traits.
Constructions of Social Exclusion Among Young People From Interface Areas of Northern Ireland
Authors: Hargie Owen , O’Donnell Aodheen , McMullan Christel
Published: April 2010

The concept of social exclusion has attracted considerable interest and debate over the past 20 years. It is a multifaceted concept, which has been delineated in a variety of ways by different theorists. This article explores the main defining features of social exclusion, and proceeds to investigate the extent to which these are manifested in practice, in relation to the lived experiences of young people from deprived interface areas of Belfast. These young people are at the cutting edge of the divisions that have blighted Northern Ireland society. This qualitative study used interviews, firstly to ascertain the views of the young people themselves, and, secondly, to gauge the perceptions of community group leaders, training providers and employers who deal closely with them. Marked differences were found between the young people and the adult groups in relation to the social construction of exclusion and its impact on the young people.
Need Threat Can Motivate Performance After Ostracism
Authors: Jamieson Jeremy P. , Harkins Stephen G. , Williams Kipling D.
Published: April 2010

Ostracism threatens fundamental needs of belonging, self-esteem, control, and meaningful existence, which should motivate participants to respond to this threat. However, research has yet to examine the role of need threat in producing motivation after ostracism. In the current work, participants completed a “cognitive ability” (antisaccade) task following Cyberball-induced ostracism or inclusion. In two experiments, it was found that when ostracized, participants do not see antisaccade performance as a means of responding to the concerns produced by need threat; they respond only to the social threat, leading to worse performance than included participants (Experiments 1 and 2). However, when participants see an avenue of response (the Cyberball players can compare antisaccade performances), ostracized participants outperform included participants (Experiment 2). Moreover, this effect was mediated by the need for belonging, suggesting that ostracized participants were motivated to elevate their inclusionary status by demonstrating their worth on the cognitive ability task.
Semantic Web: Who is who in the field — a bibliometric analysis
Authors: Ying Ding
Published: April 2010

The Semantic Web (SW) is one of the main efforts aiming to enhance human and machine interaction by representing data in an understandable way for machines to mediate data and services. It is a fast-moving and multidisciplinary field. This study conducts a thorough bibliometric analysis of the field by collecting data from Web of Science (WOS) and Scopus for the period of 1960—2009. It utilizes a total of 44,157 papers with 651,673 citations from Scopus, and 22,951 papers with 571,911 citations from WOS. Based on these papers and citations, it evaluates the research performance of the SW by identifying the most productive players, major scholarly communication media, highly cited authors, influential papers and emerging stars.
What lies behind the averages and significance of citation indicators in different disciplines?
Authors: Lancho-Barrantes Bárbara S. , Guerrero-Bote Vicente P. , Moya-Anegón Félix
Published: April 2010

The limitations of citation-based indicators include a lack of coverage, no normalization with respect to the length of reference lists (with a potential bias in favour of reviews), and different citation habits. As a consequence, the distributions of the indicators are not comparable across different disciplines. Here we show that the most popular journal citation indicators used in quality assessment — the journal impact factors of Thomson Scientific and the scientific journal rankings of Scopus — are strongly correlated with the proportion of within-database references, and even more so with the number of within-database recent references per paper. No significant correlations were found with other bibliometric magnitudes. We anticipate that these results will be a starting point for more sophisticated indicator models that take this dependence into account, and for the design of strategies aimed at extending such bibliometric databases as Thomson Scientific’s Science Citation Index or Elsevier’s Scopus to improve their capacity to evaluate all sciences.
Co-citations as citation endorsements and co-links as link endorsements
Authors: Mutalikdesai Mandar R. , Srinivasa Srinath
Published: April 2010

Co-citations and co-links have long been used as measures of topical relatedness between documents in various datasets. However, there are some characteristic differences between co-citations in scientific literature and co-links in hypertext due to the underlying difference in the motivations for creating citations and links. While citations are created for formal scholarly communication, links are created for a variety of formal as well as informal purposes. We elaborate on these differences, and propose interpretations of a co-citation as an endorsement of a citation, and a co-link as an endorsement of a link. Such an interpretation is useful for focused or topical surfers to follow citations and links that are pertinent to a topic of interest in scientific literature and the web respectively.
Israeli Adolescents Exposed to Community and Terror Violence: The Protective Role of Social Support
Authors: Brookmeyer Kathryn A. , Henrich Christopher C. , Cohen Guina , Shahar Golan
Published: April 2010

This study investigates how social support may protect Israeli early adolescents who have witnessed community violence from engaging in violent behavior when they have also witnessed terror violence. The study examines how support from parents, school, and friends could serve as protective, despite the interactive risk effects of witnessing community and terror violence. In general, results indicate that support from parents operated as a protective factor, whereas support from friends acted as a risk by increasing the likelihood of violent behavior. Support from school has both a protective and risk effect, depending on the type of violence exposure witnessed. The extent to which these facets of social support operated as risk or protective factors is conditional on whether youth had also witnessed terror violence, and terror violence appear to moderate each of the three facets of support differently. The implications of these findings and intervention initiatives for Israeli youth are discussed.
Responsibility and nanotechnology
Authors: McCarthy Elise , Kelty Christopher
Published: April 2010

In this paper we argue that the concept and practice of responsibility is being transformed within science and engineering. It tells the story of attempts by nanotechnologists to make responsibility ‘do-able’ and calculable in a setting where the established language and tools of risk and risk analysis are seen as inadequate. The research is based on ethnographic participant-observation at the National Science Foundation-funded Center for Biological and Environmental Nanotechnology (CBEN) at Rice University in Texas, during the period 2003 to 2007, including the controversies and public discussions it was engaged in and the creation of the International Council on Nanotechnology (ICON). CBEN began as a project to study ‘applications’ of nanotechnology to environmental and biological systems, but turned immediately to the study of ‘implications’ to biology and environment. We argue here that the notion of ‘implications’ and the language of risk employed early on addressed two separate but entangled ideas: the risks that nanomaterials pose to biology and environment, and the risks that research on this area poses to the health of nanotechnology itself. Practitioners at CBEN sought ways to accept responsibility both as scientists with a duty to protect science (from the public, from defunding, from ‘backlash’) and as citizens with a responsibility to protect the environment and biology through scientific research. Ultimately, the language of risk has failed, and in its place ideas about responsibility, prudence, and accountability for the future have emerged, along with new questions about the proper venues and ‘modes of veridiction’ by which claims about safety or responsibility might be scientifically adjudicated.
Identifying Living Arrangements That Heighten Risk for Loneliness in Later Life
Authors: Greenfield Emily A. , Russell David
Published: April 2010

Studies have identified living alone as a risk factor for loneliness in later life without examining whether other living arrangements might also pose risk. The authors used data from a national sample of adults aged 57 and older to estimate associations between a variety of living arrangements and loneliness. In contrast to respondents living with a spouse/partner, respondents who were living alone, living with children without a spouse/partner, and living with other relatives or friends without a spouse/partner reported more loneliness. Living alone was associated with greater loneliness among men than women, but living with children without a spouse/partner was associated with greater loneliness among women. Results suggest the importance for interventions aimed at reducing loneliness to target adults who live alone, as well as adults who live with others besides intimate partners, and to consider gender differences in the propensity for particular types of living arrangements to affect loneliness.
Clinical Versus Statistical Significance: Interpreting P Values and Confidence Intervals Related to Measures of Association to Guide Decision Making
Authors: Ferrill Mary J. , Brown Dana A. , Kyle Jeffrey A.
Published: April 2010

Pharmacists need to apply outcomes from studies to reduce risk and improve patient care. Interpretation of outcomes is based on a variety of assessment tools, such as P values and confidence intervals (CIs). P values determine statistical significance of data, while CIs suggest the degree of clinical application. Many health care providers might not have the skill set required to carefully examine and interpret statistical results and then are required to assume that the researchers of the study correctly interpreted and presented the statistical results. The reluctance to examine statistical data often reflects a misconception that concepts such as P values and CIs are difficult to understand, while in reality, both can be interpreted once basic definitions and applications are understood. Measures of association such as number needed to treat can serve as effective tools for quantifying important parameters that ultimately affect patient care. A basic understanding of how to interpret and apply P values and CIs enhances one’s ability to effectively assess the validity of results from the literature. An informed reader, armed with tools for critical analysis, is in the best position to evaluate studies and thereby discern which information is applicable to a specific patient care decision.
A Sectoral Comparison of Wage Levels and Wage Inequality in Human Services Industries
Authors: Ben-Ner Avner , Ren Ting , Paulson Darla Flint
Published: April 2010

The authors explore differences among for-profit, nonprofit, and local government organizations in wage levels and inequality. Based on the intrinsic-motivation perspective and agency theory, the authors hypothesize that compared to for-profit organizations, nonprofit and local government organizations (a) are less likely to provide financial incentives, (b) pay lower or higher compensation to their employees, depending on a host of factors, and (c) have less wage inequality. The authors use wage data for five narrowly defined industries in a single state (Minnesota) where all types of organization produce the same service, employ employees with similar job titles, compete in the same labor markets, and face similar regulations. They also employ detailed data from a survey administered in two of these industries. The empirical analyses lend support for the theoretical hypotheses. However, the differences across sectors are small in magnitude.
Trust and perception related to information about biofuels in Belgium
Authors: Van de Velde Liesbeth , Verbeke Wim , Popp Michael , Van Huylenbroeck Guido
Published: April 2010

Public knowledge regarding green energy is limited and there is a perceived lack of information, particularly in the case of biofuels. This study investigates the information seeking behaviour of fuel consumers with regard to biofuels, their preferences for particular elements and channels of information and their trust in information sources. The majority of respondents were interested in many elements of information, and particularly in the tax (dis)advantages associated with biofuels. They prefer to obtain information via newspapers and brochures. Scientists, environmental and consumer organizations and the government are perceived as the most trustworthy sources of information whilst word of mouth sources, journalists and the fuel sector are less well trusted. Four consumer clusters could be distinguished, on the basis of the perceived relative trustworthiness of information sources, and these clusters have significantly different socio-demographic characteristics and preferences for elements and channels of information.
Adventures in the subatomic universe: An exploratory study of a scientist–museum physics education project
Authors: MacDonald Teresa , Bean Alice
Published: April 2010

Quarked!™ is a collaborative education project between physicists, museum educators and designers that was developed to introduce youth to concepts of scale and the particulate nature of matter through hands-on museum programs and a website with animated videos, games and lesson plans. A pilot study was carried out to assess the project’s success in presenting these concepts in a fun and engaging way for an elementary and middle school aged audience, to investigate its relevance to teachers, and to explore children’s awareness of things that they cannot directly see. We found that children as young as second grade are aware of microscopic entities that can be studied indirectly. Our study also suggests that concepts of scale and matter can be presented in a way that is engaging and accessible to youth, and that teachers consider relevant to existing curricula.
Emergent technologies against the background of everyday life: Discursive psychology as a technology assessment tool
Authors: Veen M. , Gremmen B. , te Molder H. , van Woerkum C.
Published: April 2010

To understand prospective users’ reactions to emergent technologies, it is crucial to examine the interactional contexts within which these reactions take place as people’s reactions are shaped by issues that are not necessarily related to science or technology. These issues are often overshadowed or remain blind spots when descriptions or scenarios of proposed technologies are thematized as being the core objects of reference. We therefore recommend also studying prospective users’ everyday-life practices in their own right, and in naturalistic settings. Insight into the social actions people accomplish in their everyday talk, such as establishing a particular identity, can help innovators translate prospective users’ concerns into relevant technology characteristics. We propose discursive psychology as an analytic tool to do this and show its merit with a few illustrative examples.
Violence against Women in the River Plate Region: Networks of Resistance
Authors: Clavero White Carolina , Solares Miriam , Starr Rachel , Ukaski Mónica C.
Published: April 2010

Domestic violence is endemic across Latin America. It is legitimated by patriarchal Christian theologies and widespread gender inequality. Drawing on the work of women theologians and activists working in Argentina, Uruguay and elsewhere, this article explores women's networks of resistance against violence. These include public and legal acknowledgement of domestic violence; the transmission of life-affirming values; pastoral support in the denouncement of violence; and the development of open and fluid household structures.
Theories of Self and Cognition
Authors: Paranjpe Anand C.
Published: April 2010

In this article, select theories of self and cognition from the Indian tradition are examined and interpreted in light of contemporary psychology. The affirmation and denial of the self in respectively the Upaniṣadic and Buddhist traditions of India are explained and are critically compared with their counterparts in the works of Erik Erikson and B.F. Skinner. It is argued that, to properly understand the differing theories, it is necessary to carefully examine what is it that they affirm or deny in the name of self, on what grounds, and to what consequences. A theory of cognition from the Advaita school of Indian thought is outlined and explained to indicate how it enriches the view of transcendental self in the Upaniṣadic tradition. This theory is shown to be constructivist in a way similar to Piaget’s theory. A meditative technique based on the Advaita theory of cognition is briefly described, and it is pointed out how its successful practice leads to a deconstruction of the ego and also to important existential benefits. It is shown how the technique also provides a means to validate the theory. A brief account of a modern sage who successfully followed the Advaita approach to self-realisation is given by way of a case study to illustrate how it plays out in real life. The article is concluded with a discussion on Indian and Western psychologies and implications for future research.
Methodology for Building Psychological Models from Scriptures
Authors: Bhawuk Dharm P. S.
Published: April 2010

Building on the Indian Psychological literature, this article presents a methodology of how to construct models from scriptures. Four approaches to model building are proposed by presenting examples. First, models exist in the scriptures, and they need to be discovered and polished to fit with the relevant literature. Second, a content analysis of the text(s) by using keywords can lead to the development of models about constructs, such as peace, spirituality, karma, dharma, identity, etc. Third, by recognising what works in the indigenous cultures, and tracing the idea to traditional wisdom and scriptures, practical and useful theories and models can be developed. Fourth, by questioning Western concepts and models in the light of indigenous wisdom, knowledge, insights and facts, one can develop indigenous models. These approaches steer away from the pseudo-etic approach, and allow theory building that is grounded in cultural contexts. Implications for future research in Indian Psychology (IP) are discussed. It is hoped that this article will stimulate the Indian psychological movement by providing a template to bridge psychology, philosophy and spirituality.
The negative association of BMI with classroom effort in elementary school children
Authors: Ramaswamy Raja , Mirochna Michael , Perlmuter Lawrence C.
Published: April 2010

This study was designed to evaluate the association between BMI and classroom effort in third to fifth grade, ages seven through 12. Teachers, completely blinded and unaware of the study at the time of their classroom evaluations, provided reports of academic performance and effort. Boys and girls (n = 45), which are members of an ethnically diverse community, participated. In addition to classroom measures, height, weight, and percentage body fat were evaluated. A multiple regression model controlling for ethnicity, gender, and age revealed that increasing BMI scores had little association with academic performance but effort scores decreased significantly as BMI increased. This is the first study to show that elevations in BMI in children are associated with decreasing effort in an academic setting. Thus, BMI associated reductions in effort may result in suboptimal levels of performance in the academic setting as well as in other aspects of life.
Tournament Incentives, League Policy, and NBA Team Performance Revisited
Authors: Price Joseph , Soebbing Brian P. , Berri David , Humphreys Brad R.
Published: April 2010

Taylor and Trogdon found evidence of shirking under some, but not all, draft lottery systems used in three different National Basketball Association (NBA) seasons. The authors use data from all NBA games played from 1977 to 2007 and a fixed effects model to control for unobservable team and season heterogeneity to extend this research. The authors find that NBA teams were more likely to intentionally lose games at the end of the regular season during the seasons where the incentives to finish last were the largest.
Effect of Knit Structure and Finishing Treatments on Functional and Comfort Properties of Cotton Knitted Fabrics
Authors: Ibrahim N.A. , Khalifa T.F. , El-Hossamy M.B. , Tawfik T.M.
Published: April 2010

This study demonstrated that the changes in functional and comfort properties of knitted cotton fabrics were determined by the knitted structure as well as type and concentration of finishing agent. To improve the comfort properties, one should ensure the smoothness of fabric surface, air permeability, heat transmittance as well as hydrophilicity of the knitted fabrics, by selecting the proper knit structure and/or by applying the proper finish such as bio-finish. Soft-finished fabric samples had lower tendency to shrinkage and lower stiffness unless compared with other finished fabrics. The functional properties of the finished cotton knits, i.e., antibacterial and water repellent, depend to a great extent on the type of finish.
The Backlash on “Roosting Chickens”: The Continued Atmosphere of Suppressing Indigenous Perspectives
Authors: Wootton Kathleen , Stonebanks Christopher D.
Published: April 2010

What parallels can be drawn between the fierce responses (an attack on his morality, his scholarship, his ethnicity, etc.), Professor Ward Churchill draws from his critique of U.S. foreign policy and the average teacher who attempts to include counternarratives and Indigenous perspectives within their classroom. Within this article, the authors will not go in depth into Churchill’s thesis; rather, the authors use it as a “stepping stone” to discuss the challenges facing teachers who utilize critical pedagogy and Indigenous epistemologies to create transformative classrooms.
Management of multidrug-resistant tuberculosis: an update
Authors: Monedero Ignacio , Caminero José A.
Published: April 2010

Multidrug-resistant tuberculosis (MDR-TB) is threatening control of TB in many parts of the world. As a result of limited treatment options, patients have a poor prognosis and low chances of cure. This situation can be exacerbated by HIV epidemics. In some cases, the risk exists of a real shift from susceptible to resistant strains. Despite its relevance, currently there are more contradictions and confusion surrounding MDR-TB than hard evidence. No randomized controlled trials have been performed and published evidence is limited. Rather than just the selection of expensive drugs, MDR-TB management requires well-structured programmes with a comprehensive approach, which involve the actions of a wide range of participants. Even with current investments in research and development, new drugs and vaccines will take many years to be applied in low and middle income countries. The most successful results will depend on the optimization of existing tools. The majority of the patients, even those with extensive patterns of bacilli resistance, have a possibility of cure if current clinical knowledge and effective logistics are applied. This paper is a critical review of current best practice regarding the diagnosis and treatment of MDR-TB.
Assessment of Parenting Stress Related to Treatment and Management of a Child With Medium Chain Acyl-CoA Dehydrogenase Deficiency Identified by Newborn Screening
Authors: Torkelson Roseann , Trahms Cristine M.
Published: April 2010

Medium chain acyl-CoA dehydrogenase (MCAD) deficiency, the most common defect in β -oxidation of fatty acids, occurs in approximately 1 in 15 000 live births. With the disorder, intolerance to fasting, impaired ketogenesis, and hypoglycemic coma may lead to metabolic crisis and/or irreversible neurological impairment. Although most states now test newborns for MCAD, few publications address treatment of children with MCAD deficiency or the stress parents may experience in caring for their children. Parents of all children with MCAD deficiency identified by newborn screening and followed by the Biochemical Genetics Clinic in Washington State were surveyed via a questionnaire specific to MCAD to determine treatment and management practices and were given the Parenting Stress Index—Short Form questionnaire. Seventy-eight percent (n = 11) of eligible parents responded. The mean parenting stress score among respondents (60) was significantly lower (P = .01) than were normative levels for the US population (71). Openended survey questions indicated that clear guidelines for management and treatment, as well as personal and professional support, may contribute to the relatively low parenting stress levels recorded in this population, thus providing some insight into what services health care providers should offer to parents of a child with MCAD deficiency.
Microstructural evolution of grain refined in situ Sip/ZA27 composite during partial remelting
Authors: Chen T J , Fu M F , Ma Y , Li Y D , Hao Y
Published: April 2010

The microstructural evolution of Si particle reinforced ZA27 (Sip/ZA27) composite refined by Zr and rare earth was investigated during partial remelting. The phase transformations and the effect of the Si particles were also discussed. The results indicated that a semisolid microstructure with small and spheroidal primary particles could be obtained after being partially remelted. The microstructural evolution was divided into four steps, the initial rapid coarsening, structure separation, spheroidisation and final coarsening, which resulted from the phase transformations of α+ η+ ϵ→ β, η+ β+ ϵ+Si→L and β→ α′+L, Si+ α′→L, and Si+ α′→L and L→Si+ α′ respectively. The variation of the primary particle size with heating time obeyed the Lifshitz, Slyozov and Wagner law during the final coarsening stage. The Si particles had no effect on the general microstructural evolution steps of the ZA27 matrix. But due to the effect of Si element on the as cast microstructure, the final coarsening step could be further divided into two stages. Furthermore, the evolution progress of the four steps was slowered due to the existence of the Si particles. The size of the Si particles first decreased due to their partial remelting and then coarsened because of Ostwald ripening, and their morphologies first became blunt and then spheroidal.
Effect of mixed mode I/II on fracture behaviour of laminated metal matrix composites
Authors: Hassan H A
Published: April 2010

The effects of mixed mode loading (I/II) on the fracture toughness and fracture behaviour of both 6090/SiC/20p-6013 diffusion bonded laminates and 2080/SiC/20p-2080 adhesive bonded laminates tested in the crack arrester orientation were investigated. The effects of layer thickness and volume fraction ratio on the fracture behaviour under the mixed mode were also studied. The fracture behaviour under mode I/II of available similar discontinuously reinforced aluminium (DRA) materials was additionally compared to that of the laminates. The fracture behaviour of laminates under mode I/II was dependent on the volume fraction ratio and generally different from that of the monolithic and DRA. The increase in the fracture toughness of DRA by lamination with ductile layers under mode I changes somewhat under increasing load mixity, for 75/25 and 50/50 diffusion bonded laminate and 60/40 adhesive bonded laminate ABL. This results from extensive interfacial separation and delamination between the layers.
Study of microstructural and mechanical properties of weld heat affected zones of 2024-T3 aluminium using Gleeble simulation
Authors: Yang J. G. , Sung S. H. , Chen C. S. , Tan A. H.
Published: April 2010

The effect of the microstructural properties on the mechanical properties of welding thermal cycles and post-weld heat treatment of the heat affected zone (HAZ) in 2024-T3 aluminium alloy has been investigated. Gleeble HAZ simulation, differential scanning calorimetry, TEM and tensile test have been utilised to investigate the regions representative of HAZ microstructures. The decay of strength in the weld HAZ is primarily due to the precipitation and coarsening of stable S phases. The welded HAZ in the region at peak temperature of 414°C has the lowest strength after natural aged temper. Post-weld T81 artificial aging (PWAA-T81) heat treatment at 190°C for 12 h has no effect on improving the HAZ strength; the HAZ strength of 2024-T3 alloy obtained by PWAA-T81 treatment is less than that obtained by natural aging, and its lowest strength is shifted to the region of the peak temperature, which is 452°C. Scanning electron microscopy observation reveals that the fracture mode changes from transgranular to intergranular failure when the 2024 specimen is exposed to a thermal cycle up to a peak temperature of 550°C. This is caused by the liquation of grain boundary segregates or formation of a eutectic structure while the specimen is subjected to high temperature thermal cycles during welding, which results in a decrease in the strength and ductility of the grain boundary. It is also shown that the decrease in ductility in this high temperature HAZ cannot be improved using the PWAA-T81 heat treatment.
Effects of microstructure on high strain rate deformation and flow behaviour of Al–Mg–Si alloy (AA 6061) under uniaxial compression and combined compression and shear loading
Authors: Tang X. , Li D. , Prakash V. , Lewandowski J. J.
Published: April 2010

In the present study, high strain rate deformation and flow characteristics of AA 6061 were investigated under dynamic uniaxial compression and combined compression and shear loading conditions. The uniaxial compressive behaviour was obtained at strain rates in the range of 102–104 s−1 using a split Hopkinson pressure bar (SHPB); ultrahigh strain rate plate impact compression and shear experiments were conducted to investigate the material behaviour at plastic strain rates in excess of 104 s−1. In order to understand the effect of material microstructure on the mechanical behaviour of the AA 6061 alloy, both the T6 and overaged (OA) heat treatments were investigated. The results of the SHPB experiments indicate that the two heat treatments show positive strain rate sensitivity at strain rates up to 4660 s−1. However, at strain rates in excess of 4660 s−1, Al6061-T6 exhibits a somewhat negative strain rate sensitivity. Estimates for temperature rise, assuming that all the plastic work is converted to heat, indicate that the specimen temperature may be elevated into a regime where both thermal effects on the flow stress and the resulting strain rate sensitivity change the flow stress response. This suggests that one contributing reason for the observed decrease in flow stress at the highest strain rates is due to thermal softening. Moreover, at strain rates in excess of 104 s−1, the flow stress levels for both the Al6061-T6 and Al6061-OA heat treatments are observed to approach their saturation stress levels.
Hemgn is a direct transcriptional target of HOXB4 and induces expansion of murine myeloid progenitor cells
Authors: Jiang Jie , Yu Hui , Shou Yan , Neale Geoffrey , Zhou Sheng , Lu Taihe , Sorrentino Brian P.
Published: April 2010

HOXB4, a member of the Homeobox transcription factor family, promotes expansion of hematopoietic stem cells and hematopoietic progenitor cells in vivo and ex vivo when overexpressed. However, the molecular mechanisms underlying this effect are not well understood. To identify direct target genes of HOXB4 in primary murine hematopoietic progenitor cells, we induced HOXB4 function in lineage-negative murine bone marrow cells, using a tamoxifen-inducible HOXB4-ERT2 fusion protein. Using expression microarrays, 77 probe sets were identified with differentially changed expression in early response to HOXB4 induction. Among them, we show that Hemogen (Hemgn), encoding a hematopoietic-specific nuclear protein of unknown function, is a direct transcriptional target of HOXB4. We show that HOXB4 binds to the promoter region of Hemgn both ex vivo and in vivo. When we overexpressed Hemgn in bone marrow cells, we observed that Hemgn promoted cellular expansion in liquid cultures and increased self-renewal of myeloid colony-forming units in culture, partially recapitulating the effect of HOXB4 overexpression. Furthermore, down-regulation of Hemgn using an shRNA strategy proved that Hemgn contributes to HOXB4-mediated expansion in our myeloid progenitor assays. Our results identify a functionally relevant, direct transcriptional target of HOXB4 and identify other target genes that may also participate in the HOXB4 genetic network.
Expression and role of FLT3 in regulation of the earliest stage of normal granulocyte-monocyte progenitor development
Authors: Böiers Charlotta , Buza-Vidas Natalija , Jensen Christina T. , Pronk Cornelis J. H. , Kharazi Shabnam , Wittmann Lilian , Sitnicka Ewa , Hultquist Anne , Jacobsen Sten Eirik W.
Published: April 2010

Mice deficient in c-fms–like tyrosine kinase 3 (FLT3) signaling have reductions in early multipotent and lymphoid progenitors, whereas no evident myeloid phenotype has been reported. However, activating mutations of Flt3 are among the most common genetic events in acute myeloid leukemia and mice harboring internal tandem duplications within Flt3 (Flt3-ITD) develop myeloproliferative disease, with characteristic expansion of granulocyte-monocyte (GM) progenitors (GMP), possibly compatible with FLT3-ITD promoting a myeloid fate of multipotent progenitors. Alternatively, FLT3 might be expressed at the earliest stages of GM development. Herein, we investigated the expression, function, and role of FLT3 in recently identified early GMPs. Flt3-cre fate-mapping established that most progenitors and mature progeny of the GM lineage are derived from Flt3-expressing progenitors. A higher expression of FLT3 was found in preGMP compared with GMP, and preGMPs were more responsive to stimulation with FLT3 ligand (FL). Whereas preGMPs and GMPs were reduced in Fl−/− mice, megakaryocyte-erythroid progenitors were unaffected and lacked FLT3 expression. Notably, mice deficient in both thrombopoietin (THPO) and FL had a more pronounced GMP phenotype than Thpo−/− mice, establishing a role of FL in THPO-dependent and -independent regulation of GMPs, of likely significance for myeloid malignancies with Flt3-ITD mutations.
Novel insights into the genomic basis of citrus canker based on the genome sequences of two strains of Xanthomonas fuscans subsp. aurantifolii
Authors: Moreira Leandro M , Almeida Nalvo F , Potnis Neha , Digiampietri Luciano A , Adi Said S , Bortolossi Julio C , da Silva Ana C , da Silva Aline M , de Moraes Fabrício E , de Oliveira Julio C , de Souza Robson F , Facincani Agda P , Ferraz André L , Ferro Maria I , Furlan Luiz R , Gimenez Daniele F , Jones Jeffrey B , Kitajima Elliot W , Laia Marcelo L , Leite Rui P , Nishiyama Milton Y , Rodrigues Neto Julio , Nociti Letícia A , Norman David J , Ostroski Eric H , Pereira Haroldo A , Staskawicz Brian J , Tezza Renata I , Ferro Jesus A , Vinatzer Boris A , Setubal João C
Published: April 2010

Background

Citrus canker is a disease that has severe economic impact on the citrus industry worldwide. There are three types of canker, called A, B, and C. The three types have different phenotypes and affect different citrus species. The causative agent for type A is Xanthomonas citri subsp. citri, whose genome sequence was made available in 2002. Xanthomonas fuscans subsp. aurantifolii strain B causes canker B and Xanthomonas fuscans subsp. aurantifolii strain C causes canker C.

Results

We have sequenced the genomes of strains B and C to draft status. We have compared their genomic content to X. citri subsp. citri and to other Xanthomonas genomes, with special emphasis on type III secreted effector repertoires. In addition to pthA, already known to be present in all three citrus canker strains, two additional effector genes, xopE3 and xopAI, are also present in all three strains and are both located on the same putative genomic island. These two effector genes, along with one other effector-like gene in the same region, are thus good candidates for being pathogenicity factors on citrus. Numerous gene content differences also exist between the three cankers strains, which can be correlated with their different virulence and host range. Particular attention was placed on the analysis of genes involved in biofilm formation and quorum sensing, type IV secretion, flagellum synthesis and motility, lipopolysacharide synthesis, and on the gene xacPNP, which codes for a natriuretic protein.

Conclusion

We have uncovered numerous commonalities and differences in gene content between the genomes of the pathogenic agents causing citrus canker A, B, and C and other Xanthomonas genomes. Molecular genetics can now be employed to determine the role of these genes in plant-microbe interactions. The gained knowledge will be instrumental for improving citrus canker control.
The impact of ColRS two-component system and TtgABC efflux pump on phenol tolerance of Pseudomonas putida becomes evident only in growing bacteria
Authors: Putrinš Marta , Ilves Heili , Lilje Liisa , Kivisaar Maia , Hõrak Rita
Published: April 2010

Background

We have recently found thatPseudomonas putidadeficient in ColRS two-component system is sensitive to phenol and displays a serious defect on solid glucose medium where subpopulation of bacteria lyses. The latter phenotype is significantly enhanced by the presence of phenol in growth medium. Here, we focused on identification of factors affecting phenol tolerance of thecolR-deficientP. putida.

Results

By using transposon mutagenesis approach we identified a set of phenol-tolerant derivatives ofcolR-deficient strain. Surprisingly, half of independent phenol tolerant clones possessed miniTn5 insertion in thettgABCoperon. However, though inactivation of TtgABC efflux pump significantly enhanced phenol tolerance, it did not affect phenol-enhanced autolysis of thecolRmutant on glucose medium indicating that phenol- and glucose-caused stresses experienced by thecolR-deficientP. putidaare not coupled. Inactivation of TtgABC pump significantly increased the phenol tolerance of the wild-typeP. putidaas well. Comparison of phenol tolerance of growingversusstarving bacteria revealed that both ColRS and TtgABC systems affect phenol tolerance only under growth conditions and not under starvation. Flow cytometry analysis showed that phenol strongly inhibited cell division and to some extent also caused cell membrane permeabilization to propidium iodide. Single cell analysis of populations of thettgC-andcolRttgC-deficient strains revealed that their membrane permeabilization by phenol resembles that of the wild-type and thecolRmutant, respectively. However, cell division ofP. putidawith inactivated TtgABC pump seemed to be less sensitive to phenol than that of the parental strain. At the same time, cell division appeared to be more inhibited in thecolR-mutant strain than in the wild-typeP. putida.

Conclusions

ColRS signal system and TtgABC efflux pump are involved in the phenol tolerance ofP. putida. However, as they affect phenol tolerance of growing bacteria only, this indicates that they participate in the regulation of processes which are active during the growth and/or cell division. Single cell analysis data indicated that the cell division step of cell cycle is particularly sensitive to the toxic effect of phenol and its inhibition can be considered as an adaptive response under conditions of phenol stress.