5,685 research outputs found
Remarks on Higgs Inflation
We discuss models where the Higgs boson of the electroweak standard model
plays the role of the inflaton. We focus on the question of the violation of
perturbative unitarity due to the coupling of the Higgs boson either to the
Ricci scalar or to the Einstein tensor and discuss the background dependence of
the unitarity bounds. Our conclusion is that the simplest model which restricts
itself to the standard model Higgs boson without introducing further degrees of
freedom has a serious problem. However, in the asymptotically safe gravity
scenario, the Higgs boson of the standard model could be the inflaton and no
physics beyond the standard model is required to explain both inflation and the
spontaneous breaking of the electroweak symmetry of the standard model.Comment: 9 pages. Version 2: Final Phys. Lett. B version, includes further
discussion of singlet scala
Flow maldistribution in industrial air heaters and its effect on heat transfer
Flow maldistribution in cross-flow heat exchangers used for industrial air heaters or recuperators is fairly common and can lead to a number of undesirable effects, one of which is deterioration in the thermal performance. The effect of gross flow maldistribution and the improvement in the thermal performance of flow correction guide vanes is investigated using a laboratory heat exchanger apparatus. The thermal performance deterioration from maldistribution was up to around 30 %. Modest improvements in the overall heat transfer coefficient and heat exchanger effectiveness when vanes were used was found for the range of air-side Reynolds numbers tested. Vanes were found to reduce the deterioration in thermal performance by up to 60 % compared to a perfectly uniform flow situation. Based on the ε-NTU correlations the thermal performance deterioration is predicted to decrease as the number of tube rows (i.e. NTU) increases. The effective heat transfer area and therefore thermal performance of industrial air heaters and recuperators can be improved by using flow correction devices, such as guide vanes
The Fermi view of gamma-ray bursts
Since its successful launch in June 2008, the {\it Fermi} Gamma-ray Space
Telescope has made important breakthroughs in the understanding of the
Gamma-Ray Burst (GRB) phenomemon. The combination of the GBM and the LAT
instruments onboard the {\it Fermi} observatory has provided a wealth of
information from its observations of GRBs over seven decades in energy. We
present brief descriptions of the {\it Fermi} instruments and their
capabilities for GRB science, and report highlights from {\it Fermi}
observations of high-energy prompt and extended GRB emission. The main physical
implications of these results are discussed, along with open questions
regarding GRB modelling. We emphasize future synergies with ground-based
\v{C}erenkov telescopes at the time of the SVOM mission.Comment: 10 pages, 10 figures -- Published in a special issue of Comptes
Rendus Physique "GRB studies in the SVOM era", Eds. F. Daigne, G. Dubu
The Genre of the Royal Crisis Address: Six European Monarchs’ Rhetorical Responses to the Covid-19 Pandemic
This article offers a rhetorical analysis of the addresses delivered by six Northern European monarchs in response to the Covid-19 pandemic in early 2020. The analysis establishes a new genre with distinctive traits and functions: They royal crisis address. This genre has two constitutive traits: To demonstrate the seriousness of the situation and to constitute the citizens and encourage them to behave in the right way. The genre also has three optional traits: to provide thanks, to empathise with those affected, and to reassure and inspire the nation. In a national crisis such as the Covid-19 pandemic, these rhetorical functions will also be performed by national leaders, however, because of the apolitical position and charismatic and historical power of the royals in the North European monarchies the royals can perform these functions with a special authority. We describe how this is done through the five functions and through epideictic and constitutive rhetoricpublishedVersio
Effect of pediatric influenza vaccination on antibiotic resistance in England and Wales
Vaccines against viral infections have been proposed to reduce prescribing of antibiotics and thereby help control resistant bacterial infections. However, by combining published data sources, we predict that pediatric live attenuated influenza vaccination in England and Wales will not substantially reduce antibiotic consumption or adverse health outcomes associated with antibiotic resistance
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Direct and indirect effects of rotavirus vaccination: Comparing predictions from transmission dynamic models
Early observations from countries that have introduced rotavirus vaccination suggest that there may be indirect protection for unvaccinated individuals, but it is unclear whether these benefits will extend to the long term. Transmission dynamic models have attempted to quantify the indirect protection that might be expected from rotavirus vaccination in developed countries, but results have varied. To better understand the magnitude and sources of variability in model projections, we undertook a comparative analysis of transmission dynamic models for rotavirus. We fit five models to reported rotavirus gastroenteritis (RVGE) data from England and Wales, and evaluated outcomes for short- and long-term vaccination effects. All of our models reproduced the important features of rotavirus epidemics in England and Wales. Models predicted that during the initial year after vaccine introduction, incidence of severe RVGE would be reduced 1.8-2.9 times more than expected from the direct effects of the vaccine alone (28-50% at 90% coverage), but over a 5-year period following vaccine introduction severe RVGE would be reduced only by 1.1-1.7 times more than expected from the direct effects (54-90% at 90% coverage). Projections for the long-term reduction of severe RVGE ranged from a 55% reduction at full coverage to elimination with at least 80% coverage. Our models predicted short-term reductions in the incidence of RVGE that exceeded estimates of the direct effects, consistent with observations from the United States and other countries. Some of the models predicted that the short-term indirect benefits may be offset by a partial shifting of the burden of RVGE to older unvaccinated individuals. Nonetheless, even when such a shift occurs, the overall reduction in severe RVGE is considerable. Discrepancies among model predictions reflect uncertainties about age variation in the risk and reporting of RVGE, and the duration of natural and vaccine-induced immunity, highlighting important questions for future research
Enhancement of vaccinia virus based oncolysis with histone deacetylase inhibitors
Histone deacetylase inhibitors (HDI) dampen cellular innate immune response by decreasing interferon production and have been shown to increase the growth of vesicular stomatitis virus and HSV. As attenuated tumour-selective oncolytic vaccinia viruses (VV) are already undergoing clinical evaluation, the goal of this study is to determine whether HDI can also enhance the potency of these poxviruses in infection-resistant cancer cell lines. Multiple HDIs were tested and Trichostatin A (TSA) was found to potently enhance the spread and replication of a tumour selective vaccinia virus in several infection-resistant cancer cell lines. TSA significantly decreased the number of lung metastases in a syngeneic B16F10LacZ lung metastasis model yet did not increase the replication of vaccinia in normal tissues. The combination of TSA and VV increased survival of mice harbouring human HCT116 colon tumour xenografts as compared to mice treated with either agent alone. We conclude that TSA can selectively and effectively enhance the replication and spread of oncolytic vaccinia virus in cancer cells. © 2010 MacTavish et al
Problems with Using Evolutionary Theory in Philosophy
Does science move toward truths? Are present scientific theories (approximately) true? Should we invoke truths to explain the success of science? Do our cognitive faculties track truths? Some philosophers say yes, while others say no, to these questions. Interestingly, both groups use the same scientific theory, viz., evolutionary theory, to defend their positions. I argue that it begs the question for the former group to do so because their positive answers imply that evolutionary theory is warranted, whereas it is self-defeating for the latter group to do so because their negative answers imply that evolutionary theory is unwarranted
Marine ecosystem services: Linking indicators to their classification
© 2014 Elsevier Ltd. All rights reserved. There is a multitude of ecosystem service classifications available within the literature, each with its own advantages and drawbacks. Elements of them have been used to tailor a generic ecosystem service classification for the marine environment and then for a case study site within the North Sea: the Dogger Bank. Indicators for each of the ecosystem services, deemed relevant to the case study site, were identified. Each indicator was then assessed against a set of agreed criteria to ensure its relevance and applicability to environmental management. This paper identifies the need to distinguish between indicators of ecosystem services that are entirely ecological in nature (and largely reveal the potential of an ecosystem to provide ecosystem services), indicators for the ecological processes contributing to the delivery of these services, and indicators of benefits that reveal the realized human use or enjoyment of an ecosystem service. It highlights some of the difficulties faced in selecting meaningful indicators, such as problems of specificity, spatial disconnect and the considerable uncertainty about marine species, habitats and the processes, functions and services they contribute to
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