Magnetically Responsive Silicon Carbide Whiskers for Enhanced Nanocomposite Materials

Boeing’s 787 Dream Liner, GE’s wind turbine blades, and Ferrari’s F1 chassis demonstrate the accomplishments of designed directionality in carbon fiber/epoxy composites. The aerospace, energy and transportation industries demand composite material with enhanced multifunctional properties including ultimate strength and toughness. Despite sizeable improvements, composite utilization is limited by the fiber’s low surface-area-to-volume ratio (specific surface). Orientation in man-made composites has been the key to effective strengthening of materials under mechanical load and compensating for intrinsic limitations of the current technology. Nanocomposites can drive performance to new heights by increasing the fiber to matrix interaction. Thus far, the embedding of nanomaterials into composites has been achieved, but directional arrangement has proved to be a challenging task. Even with advances in insitu, shear, and stress orientation, these methods are both difficult to control and unreliable, hampering nanocomposite improvements. Therefore, the implementation of nanomaterials with a natural ability to orient along a magnetic field will create a controlled system with precisely designed morphology. To this end, the proposed project has develop an effective approach for the design of magnetically active nanowhiskers to form 2D aligned structures in a polymer matrix, creating novel nanocomposites with enhanced mechanical properties

The challenge of managing informally

Purpose – The purpose of this paper is to explore the orientations of line managers in handling workplace conflict. In particular it examines the tension between the traditional preference of frontline managers for informal approaches and the perceived certainty of written disputes procedures. Design/methodology/approach – The paper draws upon findings from 12 organisational case studies, focusing on interviews conducted with HR and managers. Findings – As line managers undertake more responsibility for people management, their preferences for informal approaches to workplace issues appears to be being replaced by a more rigid adherence to policy and procedure. This is largely driven by a lack of confidence and expertise in conflict management and a fear of the repercussions (both legal and organisational) of mishandling difficult issues. Written procedure therefore provides managers with both a systematic guide but also a protective shield against criticism and litigation. Research limitations/implications – It is not possible to generalise from a limited sample, therefore this suggested change requires further exploration to assess whether it has been evidenced in organisations more widely. Practical implications – For practitioners this research highlights the critical requirement for organisations to develop key skills among line managers to enable them to respond effectively to problems at an early stage. Social implications – For policy-makers, the barriers to line managers implementing informal resolution should be considered. Originality/value – This paper enriches understanding of line managers’ current role in people management and the challenges they face in doing so informally

Significance of herpesvirus immediate early gene expression in cellular immunity to cytomegalovirus infection

Interstitial pneumonia linked with reactivation of latent human cytomegalovirus due to iatrogenic immunosuppression can be a serious complication of bone marrow transplantation therapy of aplastic anaemia and acute leukaemia1. Cellular immunity plays a critical role in the immune surveillance of inapparent cytomegalovirus infections in man and the mouse1−7. The molecular basis of latency, however, and the interaction between latently or recurrently infected cells and the immune system of the host are poorfy understood. We have detected a so far unknown antigen in the mouse model. This antigen is found in infected cells in association with the expression of the herpesvirus 'immediate early' genes and is recognized by cytolytic T lymphocytes (CTL)8. We now demonstrate that an unexpectedly high proportion of the CTL precursors generated in vivo during acute murine cytomegalovirus infection are specific for cells that selectively synthesize immediate early proteins, indicating an immunodominant role of viral non-structural proteins

Carboxyhaemoglobin levels and their determinants in older British men

Background: Although there has been concern about the levels of carbon monoxide exposure, particularly among older people, little is known about COHb levels and their determinants in the general population. We examined these issues in a study of older British men.Methods: Cross-sectional study of 4252 men aged 60-79 years selected from one socially representative general practice in each of 24 British towns and who attended for examination between 1998 and 2000. Blood samples were measured for COHb and information on social, household and individual factors assessed by questionnaire. Analyses were based on 3603 men measured in or close to (< 10 miles) their place of residence.Results: The COHb distribution was positively skewed. Geometric mean COHb level was 0.46% and the median 0.50%; 9.2% of men had a COHb level of 2.5% or more and 0.1% of subjects had a level of 7.5% or more. Factors which were independently related to mean COHb level included season (highest in autumn and winter), region (highest in Northern England), gas cooking (slight increase) and central heating (slight decrease) and active smoking, the strongest determinant. Mean COHb levels were more than ten times greater in men smoking more than 20 cigarettes a day (3.29%) compared with non-smokers (0.32%); almost all subjects with COHb levels of 2.5% and above were smokers (93%). Pipe and cigar smoking was associated with more modest increases in COHb level. Passive cigarette smoking exposure had no independent association with COHb after adjustment for other factors. Active smoking accounted for 41% of variance in COHb level and all factors together for 47%.Conclusion: An appreciable proportion of men have COHb levels of 2.5% or more at which symptomatic effects may occur, though very high levels are uncommon. The results confirm that smoking (particularly cigarette smoking) is the dominant influence on COHb levels

Spectral changes and wavelength dependent thermoluminescence of rare earth ions after X-ray irradiation

The thermoluminescence spectra of rare earth doped materials after X-ray irradiation typically vary with the glow peak temperature. Additionally, there are many examples where, for the same dopant ion, the expected component emission lines peak, but at different temperatures. This unusual behaviour is discussed in terms of changes in proximity of coupling between trapping and recombination sites. Changes in the energy barriers for recombination influence alternative routes for charge transfer to rare earth sites which can involve different higher energy states of the rare earth dopants. Proposed mechanisms include selective tunnelling, or barrier crossing, in addition to normal charge transfer from remote trapping sites. The model successfully describes numerous examples in terms of the energy scheme for the rare earth ions. Whilst the standard emission lines are recorded in the glow curve spectra they do not always occur at the same temperature, and, even for the same rare earth dopant, they can differ by as much as 30 °C. These wavelength dependent variations in peak temperature not only offer information on the proximity of trap and recombination sites, but also introduce issues in conventional activation energy analysis when recording is with polychromatic light. The concepts are relevant for related types of measurement, such as optically stimulated thermoluminescence

Issues in the construction of wealth indices for the measurement of socio-economic position in low-income countries

BACKGROUND: Epidemiological studies often require measures of socio-economic position (SEP). The application of principal components analysis (PCA) to data on asset-ownership is one popular approach to household SEP measurement. Proponents suggest that the approach provides a rational method for weighting asset data in a single indicator, captures the most important aspect of SEP for health studies, and is based on data that are readily available and/or simple to collect. However, the use of PCA on asset data may not be the best approach to SEP measurement. There remains concern that this approach can obscure the meaning of the final index and is statistically inappropriate for use with discrete data. In addition, the choice of assets to include and the level of agreement between wealth indices and more conventional measures of SEP such as consumption expenditure remain unclear. We discuss these issues, illustrating our examples with data from the Malawi Integrated Household Survey 2004-5. METHODS: Wealth indices were constructed using the assets on which data are collected within Demographic and Health Surveys. Indices were constructed using five weighting methods: PCA, PCA using dichotomised versions of categorical variables, equal weights, weights equal to the inverse of the proportion of households owning the item, and Multiple Correspondence Analysis. Agreement between indices was assessed. Indices were compared with per capita consumption expenditure, and the difference in agreement assessed when different methods were used to adjust consumption expenditure for household size and composition. RESULTS: All indices demonstrated similarly modest agreement with consumption expenditure. The indices constructed using dichotomised data showed strong agreement with each other, as did the indices constructed using categorical data. Agreement was lower between indices using data coded in different ways. The level of agreement between wealth indices and consumption expenditure did not differ when different consumption equivalence scales were applied. CONCLUSION: This study questions the appropriateness of wealth indices as proxies for consumption expenditure. The choice of data included had a greater influence on the wealth index than the method used to weight the data. Despite the limitations of PCA, alternative methods also all had disadvantages

Surviving Sepsis Campaign: International Guidelines for Management of Sepsis and Septic Shock: 2016.

OBJECTIVE: To provide an update to "Surviving Sepsis Campaign Guidelines for Management of Sepsis and Septic Shock: 2012." DESIGN: A consensus committee of 55 international experts representing 25 international organizations was convened. Nominal groups were assembled at key international meetings (for those committee members attending the conference). A formal conflict-of-interest (COI) policy was developed at the onset of the process and enforced throughout. A stand-alone meeting was held for all panel members in December 2015. Teleconferences and electronic-based discussion among subgroups and among the entire committee served as an integral part of the development. METHODS: The panel consisted of five sections: hemodynamics, infection, adjunctive therapies, metabolic, and ventilation. Population, intervention, comparison, and outcomes (PICO) questions were reviewed and updated as needed, and evidence profiles were generated. Each subgroup generated a list of questions, searched for best available evidence, and then followed the principles of the Grading of Recommendations Assessment, Development, and Evaluation (GRADE) system to assess the quality of evidence from high to very low, and to formulate recommendations as strong or weak, or best practice statement when applicable. RESULTS: The Surviving Sepsis Guideline panel provided 93 statements on early management and resuscitation of patients with sepsis or septic shock. Overall, 32 were strong recommendations, 39 were weak recommendations, and 18 were best-practice statements. No recommendation was provided for four questions. CONCLUSIONS: Substantial agreement exists among a large cohort of international experts regarding many strong recommendations for the best care of patients with sepsis. Although a significant number of aspects of care have relatively weak support, evidence-based recommendations regarding the acute management of sepsis and septic shock are the foundation of improved outcomes for these critically ill patients with high mortality

Pathologies in Asymptotically Lifshitz Spacetimes

There has been significant interest in the last several years in studying possible gravitational duals, known as Lifshitz spacetimes, to anisotropically scaling field theories by adding matter to distort the asymptotics of an AdS spacetime. We point out that putative ground state for the most heavily studied example of such a spacetime, that with a flat spatial section, suffers from a naked singularity and further point out this singularity is not resolvable by any known stringy effect. We review the reasons one might worry that asymptotically Lifshitz spacetimes are unstable and employ the initial data problem to study the stability of such systems. Rather surprisingly this question, and even the initial value problem itself, for these spacetimes turns out to generically not be well-posed. A generic normalizable state will evolve in such a way to violate Lifshitz asymptotics in finite time. Conversely, enforcing the desired asymptotics at all times puts strong restrictions not just on the metric and fields in the asymptotic region but in the deep interior as well. Generically, even perturbations of the matter field of compact support are not compatible with the desired asymptotics.Comment: 36 pages, 1 figure, v2: Enhanced discussion of singularity, including relationship to Gubser's conjecture and singularity in RG flow solution, plus minor clarification