912 research outputs found

    Lime stabilisation for earthworks: a UK perspective

    Get PDF
    Lime stabilisation is a versatile technique applied during earthworks operations. Modern soil recycling units are much more efficient at pulverising fill material and intermixing the added binder/water than machinery available 20 years ago. While supplier innovation adds flexibility to the site working method, specifications have not been sufficiently updated to permit optimal application. This review paper details the physico-chemical changes instigated through the lime-clay soil reaction, updating previous reviews. It aims to assist scientific debate, current practitioners and future specification changes. For example, the application of the minimum 24 h mellowing periods (mandatory to UK specifications) with high reactivity, quicklime powders is concluded to cause increased air voids in the compacted fill. Increased air voids are associated with reduced long-term strength and potential volume change from water ingress, which is of particular concern for sulfate swelling. Shorter mellowing periods and/or use of hydrated lime may lesson this issue; however, a 'one size fits all' approach is discouraged in preference to site-specific methodologies refined to suit the fill material and project requirements. The discussion also summarises working methods which may lower the risk of sulfate swell and defines areas requiring further practical research

    Building Babies - Chapter 16

    Get PDF
    In contrast to birds, male mammals rarely help to raise the offspring. Of all mammals, only among rodents, carnivores, and primates, males are sometimes intensively engaged in providing infant care (Kleiman and Malcolm 1981). Male caretaking of infants has long been recognized in nonhuman primates (Itani 1959). Given that infant care behavior can have a positive effect on the infant’s development, growth, well-being, or survival, why are male mammals not more frequently involved in “building babies”? We begin the chapter defining a few relevant terms and introducing the theory and hypotheses that have historically addressed the evolution of paternal care. We then review empirical findings on male care among primate taxa, before focusing, in the final section, on our own work on paternal care in South American owl monkeys (Aotus spp.). We conclude the chapter with some suggestions for future studies.Deutsche Forschungsgemeinschaft (HU 1746/2-1) Wenner-Gren Foundation, the L.S.B. Leakey Foundation, the National Geographic Society, the National Science Foundation (BCS-0621020), the University of Pennsylvania Research Foundation, the Zoological Society of San Dieg

    Expression and trans-specific polymorphism of self-incompatibility RNases in Coffea (Rubiaceae)

    Get PDF
    Self-incompatibility (SI) is widespread in the angiosperms, but identifying the biochemical components of SI mechanisms has proven to be difficult in most lineages. Coffea (coffee; Rubiaceae) is a genus of old-world tropical understory trees in which the vast majority of diploid species utilize a mechanism of gametophytic self-incompatibility (GSI). The S-RNase GSI system was one of the first SI mechanisms to be biochemically characterized, and likely represents the ancestral Eudicot condition as evidenced by its functional characterization in both asterid (Solanaceae, Plantaginaceae) and rosid (Rosaceae) lineages. The S-RNase GSI mechanism employs the activity of class III RNase T2 proteins to terminate the growth of "self" pollen tubes. Here, we investigate the mechanism of Coffea GSI and specifically examine the potential for homology to S-RNase GSI by sequencing class III RNase T2 genes in populations of 14 African and Madagascan Coffea species and the closely related self-compatible species Psilanthus ebracteolatus. Phylogenetic analyses of these sequences aligned to a diverse sample of plant RNase T2 genes show that the Coffea genome contains at least three class III RNase T2 genes. Patterns of tissue-specific gene expression identify one of these RNase T2 genes as the putative Coffea S-RNase gene. We show that populations of SI Coffea are remarkably polymorphic for putative S-RNase alleles, and exhibit a persistent pattern of trans-specific polymorphism characteristic of all S-RNase genes previously isolated from GSI Eudicot lineages. We thus conclude that Coffea GSI is most likely homologous to the classic Eudicot S-RNase system, which was retained since the divergence of the Rubiaceae lineage from an ancient SI Eudicot ancestor, nearly 90 million years ago.United States National Science Foundation [0849186]; Society of Systematic Biologists; American Society of Plant Taxonomists; Duke University Graduate Schoolinfo:eu-repo/semantics/publishedVersio

    Emerging roles and competencies of district and sub-district pharmacists: a case study from Cape Town

    Get PDF
    District and sub-district pharmacist positions were created during health sector reform in South Africa. High prevalence of HIV/AIDS, tuberculosis and increasing chronic non-communicable diseases have drawn attention to their pivotal roles in improving accessibility and appropriate use of medicines at the primary level. This research describes new roles and related competencies of district and sub-district pharmacists in Cape Town. Between 2008 and 2011, the author (HB) conducted participatory action research in Cape Town Metro District, an urban district in the Western Cape Province of South Africa, partnering with pharmacists and managers of the two government primary health care (PHC) providers. The two providers function independently delivering complementary PHC services across the entire geographic area, with one provider employing district pharmacists and the other sub-district pharmacists. After an initiation phase, the research evolved into a series of iterative cycles of action and reflection, each providing increasing understanding of district and sub-district pharmacists’ roles and competencies. Data was generated through workshops, semi-structured interviews and focus groups with pharmacists and managers which were recorded and transcribed. Thematic analysis was carried out iteratively during the 4-year engagement and triangulated with document reviews and published literature. Five main roles for district and sub-district pharmacists were identified: district/sub-district management; planning, co-ordination and monitoring of pharmaceuticals; information and advice; quality assurance and clinical governance; and research (district pharmacists)/dispensing at clinics (sub-district pharmacists). Although the roles looked similar, there were important differences, reflecting the differing governance and leadership models and services of each provider. Five competency clusters were identified: professional pharmacy practice; health system and public health; management; leadership; and personal, interpersonal and cognitive competencies. Whilst professional pharmacy competencies were important, generic management and leadership competencies were considered critical for pharmacists working in these positions. Similar roles and competencies for district and sub-district pharmacists were identified in the two PHC providers in Cape Town, although contextual factors influenced precise specifications. These insights are important for pharmacists and managers from other districts and sub-districts in South Africa and inform health workforce planning and capacity development initiatives in countries with similar health systems.Web of Scienc

    A half-site multimeric enzyme achieves its cooperativity without conformational changes

    Get PDF
    Cooperativity is a feature many multimeric proteins use to control activity. Here we show that the bacterial heptose isomerase GmhA displays homotropic positive and negative cooperativity among its four protomers. Most similar proteins achieve this through conformational changes: GmhA instead employs a delicate network of hydrogen bonds, and couples pairs of active sites controlled by a unique water channel. This network apparently raises the Lewis acidity of the catalytic zinc, thus increasing the activity at one active site at the cost of preventing substrate from adopting a reactive conformation at the paired negatively cooperative site – a “half-site” behavior. Our study establishes the principle that multimeric enzymes can exploit this cooperativity without conformational changes to maximize their catalytic power and control. More broadly, this subtlety by which enzymes regulate functions could be used to explore new inhibitor design strategies

    Perceptions about data-informed decisions: an assessment of information-use in high HIV-prevalence settings in South Africa

    Get PDF
    BACKGROUND: Information-use is an integral component of a routine health information system and essential to influence policy-making, program actions and research. Despite an increased amount of routine data collected, planning and resource-allocation decisions made by health managers for managing HIV programs are often not based on data. This study investigated the use of information, and barriers to using routine data for monitoring the prevention of mother-to-child transmission of HIV (PMTCT) programs in two high HIV-prevalence districts in South Africa. METHODS: We undertook an observational study using a multi-method approach, including an inventory of facility records and reports. The performance of routine information systems management (PRISM) diagnostic ‘Use of Information’ tool was used to assess the PMTCT information system for evidence of data use in 57 health facilities in two districts. Twenty-two in-depth interviews were conducted with key informants to investigate barriers to information use in decision-making. Participants were purposively selected based on their positions and experience with either producing PMTCT data and/or using data for management purposes. We computed descriptive statistics and used a general inductive approach to analyze the qualitative data. RESULTS: Despite the availability of mechanisms and processes to facilitate information-use in about two-thirds of the facilities, evidence of information-use (i.e., indication of some form of information-use in available RHIS reports) was demonstrated in 53% of the facilities. Information was inadequately used at district and facility levels to inform decisions and planning, but was selectively used for reporting and monitoring program outputs at the provincial level. The inadequate use of information stemmed from organizational issues such as the lack of a culture of information-use, lack of trust in the data, and the inability of program and facility managers to analyze, interpret and use information. CONCLCUSIONS: Managers’ inability to use information implied that decisions for program implementation and improving service delivery were not always based on data. This lack of data use could influence the delivery of health care services negatively. Facility and program managers should be provided with opportunities for capacity development as well as practice-based, in-service training, and be supported to use information for planning, management and decision-making

    An Anatomy Massive Open Online Course as a Continuing Professional Development Tool for Healthcare Professionals

    Get PDF
    Massive open online courses (MOOCs) remain a novel and under-evaluated learning tool within anatomical and medical education. This study aimed to provide valuable information by using an anatomy MOOC to investigate the demographic profile, patterns of engagement and self-perceived benefits to healthcare professionals. A 21-item survey aimed at healthcare professionals was embedded into the Exploring Anatomy: The Human Abdomen MOOC, in April 2016. The course attracted 2711 individual learners with 94 of these completing the survey, and 79 of those confirming they worked full- or part-time as healthcare professionals. Variations in use across healthcare profession (allied healthcare professional, nurse or doctor) were explored using a Fisher’s exact test to calculate significance across demographic, motivation and engagement items; one-way ANOVA was used to compare self-perceived benefits. Survey data revealed that 53.2% were allied healthcare professionals, 35.4% nurses and 11.4% doctors. Across all professions, the main motivation for enrolling was to learn new things in relation to their clinical practice, with a majority following the prescribed course pathway and utilising core, and clinically relevant, material. The main benefits were in relation to improving anatomy knowledge, which enabled better support for patients. This exploratory study assessing engagement and self-perceived benefits of an anatomy MOOC has shown a high level of ordered involvement, with some indicators suggesting possible benefits to patients by enhancing the subject knowledge of those enrolled. It is suggested that this type of learning tool should be further explored as an approach to continuing professional, and interprofessional, education

    Risk propensity in the foreign direct investment location decision of emerging multinationals

    Get PDF
    A distinguishing feature of emerging economy multinationals is their apparent tolerance for host country institutional risk. Employing behavioral decision theory and quasi-experimental data, we find that managers’ domestic experience satisfaction increases their relative risk propensity regarding controllable risk (legally protectable loss), but decreases their tendency to accept non-controllable risk (e.g., political instability). In contrast, firms’ potential slack reduces relative risk propensity regarding controllable risk, yet amplifies the tendency to take non-controllable risk. We suggest that these counterbalancing effects might help explain observation that risk-taking in FDI location decisions is influenced by firm experience and context. The study provides a new understanding of why firms exhibit heterogeneous responses to host country risks, and the varying effects of institutions
    corecore