Inheritance Of Resistance To Mammalian Herbivores and Of Plant Defensive Chemistry In A <Emphasis Type="Italic">Eucalyptus</Emphasis> Species

Hybridization in plants provides an opportunity to investigate the patterns of inheritance of hybrid resistance to herbivores, and of the plant mechanisms conferring this resistance such as plant secondary metabolites. We investigated how inter-race differences in resistance of Eucalyptus globulus to a generalist mammalian herbivore, Trichosurus vulpecula, are inherited in their F₁ hybrids. We assessed browsing damage of three-year-old trees in a common environment field trial on four hybrid types of known progeny. The progency were artificial intra-race crosses and reciprocal inter-race F₁ hybrids of two geographically distinct populations (races) of E. globulus; north-eastern Tasmania and south-eastern Tasmania. Populations of trees from north-eastern Tasmania are relatively susceptible to browsing by T. vulpecula, while populations from south-eastern Tasmania are more resistant. We assessed the preferences of these trees in a series of paired feeding trials with captive animals to test the field trial results and also investigated the patterns of inheritance of plant secondary metabolites. Our results demonstrated that the phenotypic expression of resistance of the inter-race F₁ hybrids supported the additive pattern of inheritance, as these hybrids were intermediate in resistance compared to the pure parental hybrids. The expression of plant secondary metabolites in the F₁ hybrids varied among groups of individual compounds. The most common pattern supported was dominance towards one of the parental types. Together, condensed tannins and essential oils appeared to explain the observed patterns of resistance among the four hybrid types. While both chemical groups were inherited in a dominant manner in the inter-race F₁ hybrids, the direction of dominance was opposite. Their combined concentration, however, was inherited in an additive manner, consistent with the phenotypic differences in browsing.     

Exploring Relationships Between Traditional and New Media Literacies: British Preteen Texters at School

This article focuses on preteen British children's use of text messaging, particularly the abbreviations and characteristic language used within text messages. We look not only at the language style used by the children, but at the ways in which it relates to their traditional literacy skills, as measured through standardized tests and assessments. We have found repeated positive relationships between use of text register language and traditional literacy skills, and we give here a preview of our latest, longitudinal work, which allows those relationships to be studied directionally, enabling us to draw causal conclusions.     

Postural support strategies of disabled drivers and the effectiveness of postural support aids

The paper discusses a series of driving trials that were conducted to investigate postural stability of disabled drivers and to assess the effectiveness of a representative sample of support aids. Twenty-three disabled drivers with varying levels of physical disability and seven non disabled drivers participated in the study. The test car was equipped with transducers to measure vehicle velocity and acceleration (longitudinal and lateral), steering wheel movement and torque, and the bracing forces exerted by the driver on the steering wheel. Video cameras were installed to record postural support strategies and displacement of the driver and to record deviation of the car from the specified path. Subjective data regarding driver attitudes and acceptance were also collected through the administration of questionnaires. Findings from the study showed that support aids significantly improved driving performance and reduced physical exertion to maintain an upright driving position for disabled drivers. However, ergonomics design aspects regarding the ease of use and acceptance of the support aids by the end users were identified as obstacles to their sustained use in everyday driving.     

Assessing Positive and Negative Changes in the Aftermath of Adversity: Psychometric Evaluation of the Changes in Outlook Questionnaire.

The Changes in Outlook Questionnaire (CiOQ; S. Joseph, R. Williams, & W. Yule, 1993) is a 26-item self-report measure that was designed to assess positive and negative changes in the aftermath of adversity. This article had 3 aims: 1st, to investigate the factor structure of the CiOQ; 2nd, to test for internal consistency reliability and convergent and discriminant validity; and, 3rd, to investigate the association between positive and negative changes in outlook, posttraumatic stress, and psychological distress. Three studies are reported. Study 1 provides evidence that positive and negative changes are statistically separable and that the 2-factor model is a better fit than the 1-factor model. Studies 2 and 3 provide evidence for internal consistency reliability, convergent and discriminant validity of the CiOQ, and its associations with posttraumatic stress and psychological distress. In conclusion, the CiOQ has much promise for research on responses to stressful and traumatic events. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Transmission of Bacterial Zoonotic Pathogens between Pets and Humans: The Role of Pet Food

Recent Salmonella outbreaks associated with dry pet food and treats raised the level of concern for these products as vehicle of pathogen exposure for both pets and their owners. The need to characterize the microbiological and risk profiles of this class of products is currently not supported by sufficient specific data. This systematic review summarizes existing data on the main variables needed to support an ingredients-to-consumer quantitative risk model to (1) describe the microbial ecology of bacterial pathogens in the dry pet food production chain, (2) estimate pet exposure to pathogens through dry food consumption, and (3) assess human exposure and illness incidence due to contact with pet food and pets in the household. Risk models populated with the data here summarized will provide a tool to quantitatively address the emerging public health concerns associated with pet food and the effectiveness of mitigation measures. Results of such models can provide a basis for improvements in production processes, risk communication to consumers, and regulatory action.     

Influences of Plant Toxins and Their Spatial Distribution on Foraging by the Common Brushtail Possum, a Generalist Mammalian Herbivore

Generalist herbivores forage on a variety of plant species, allowing them to gain nutrients while limiting ingestion of harmful toxins. As the capacity to mix diets appears important for maximizing intake, the spatial scale in heterogeneity of food resources should influence the foraging behavior of herbivores. Our aim was to identify how the feeding strategy of a generalist mammalian herbivore, the common brushtail possum, responds to foods within a spatially defined environment. We evaluated foraging responses against increasing spatial separation between pairs of artificial diets that differed in flavor and toxin profile, to determine how distance and diet affect intake and behavior. Foraging responses were influenced by the type of diet or the degree of spatial separation between foods but not by their interaction. Diet influenced intake, time spent feeding, and feeding rate, but had no effect on nightly foraging interval, number of feeding bouts, or bout length. The number of switches between paired food resources and foraging efficiency (intake per unit distance, which accounts for the energetic costs of travelling), were influenced only by distance. Titrating foraging against a range of distances demonstrated how quickly foraging efficiency can decline in response to the spatial separation of food resources, highlighting the importance of spatial heterogeneity of plants within the home range of an herbivore.     

Workpiece debris deposition on tool electrodes and secondary discharge phenomena in micro-EDM

During electrical discharge machining (EDM), ablated workpiece material is rapidly solidified upon ejection into the dielectric and thought not to become reattached to the electrode surfaces. This work furthers the understanding of the little understood discharge gap phenomena by investigating the attachment of machined material back onto the tool electrode surface and explains the mechanism of this attachment. After the machining of high-aspect ratio slots, SEM and EDS techniques along with single discharge and cross-sectional analysis were used to explain that debris reattachment onto the tool electrode does not occur randomly but is dependent on its remelting in the dielectric by the secondary discharge process. The subsequently bonded material is present mainly in the centre of the discharge crater, with no attachment occurring outside of discharge affected regions. The surfaces of electrodes subject to intense secondary sparking are therefore liable to transient surface properties dependent on the composition of the deposited material. It is also observed that the deposited material on the tool electrode can offer a protective effect against wear from further secondary discharges and so potentially enhancing tool life.     

Engaging with Marginalised Groups in Public Open Space Research: The Potential of Collaboration and Combined Methods

This paper discusses methodological dilemmas that were encountered, and strategies used to overcome them, in the Viewfinder project that was undertaken in 2004 in Sheffield, UK. The project investigated refugees’ perceptions and experiences of urban public open space in the UK. Through partnership with a 12-week, accredited photography training course and visits to public open spaces, the research combined visual, experiential, participatory and longitudinal approaches. This paper discusses the success of these in relation to three aims: (1) generating a research situation of open communication; (2) collaborating with non-academic partners; and (3) creating mutual benefit. The research identifies methodological techniques that have potential for engaging marginalised groups in landscape and planning research and in consultation practice.