3,987 research outputs found
Mass and mixing of fermions from a rotating mass matrix
We summarize the results showing that all existing data on mixing between up
and down fermion states (i.e. CKM matrix and neutrino oscillations) and on the
hierarchical quark and lepton mass ratios between generations are consistent
with the two phenomena being both consequences of a mass matrix rotating in
generation space with changing energy scale. Thus the rotation of the mass
matrix can be traced over some 14 orders of magnitude in energy from the mass
scale of the -quark at 175 GeV to below that of the atmospheric neutrino at
0.05 eV.Comment: 13 pages latex, with 7 figures. to appear in Mod. Phys. Lett.
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Constraints on Asian and European sources of methane from Ch 4-C2H6-CO correlations in Asian outflow
Aircraft observations of Asian outflow from the Transport and Chemical Evolution Over the Pacific (TRACE-P) aircraft mission over the NW Pacific (March and April 2001) show large CH4 enhancements relative to background, as well as strong CH4-C2H 6-CO correlations that provide signatures of regional sources. We apply a global chemical transport model simulation of the CH4-C2H6-CO system for the TRACE-P period to interpret these observations in terms of CH4 sources and to explore in particular the unique constraints from the CH 4-C2H6-CO correlations. We use as a priori a global CH4 source inventory constrained with National Oceanic and Atmospheric Administration (NOAA) Climate Monitoring and Diagnostics Laboratory (CMDL) surface observations [Wang et al., 2004]. We find that the observed CH4 concentration enhancements and CH4-C2H6-CO correlations in Asian outflow in TRACE-P are deterinined mainly by anthropogenic emissions from China and Eurasia (defined here as Europe and eastern Russia), with only little contribution from tropical sources (wetlands and biomass burning). The a priori inventory overestimates the observed CH4 enhancements and shows regionally variable biases for the CH4/C2H6 slope. The CH 4/CO slopes are simulated without significant bias. Matching both the observed CH4 enhancements and the CH 4-C2H6-CO slopes in Asian outflow requires increasing the east Asian anthropogenic source of CH 4, and decreasing the Eurasian anthropogenic source, by at least 30% for both. The need to increase the east Asian source is driven by the underestimate of the CH4/C2H 6 slope in boundary layer Chinese outflow. The Streets et al. [2003] anthropogenic emission inventory for east Asia fits this constraint by increasing CH4 emissions from that region by 40% relative to the a priori, largely because of higher livestock and landfill source estimates. Eurasian sources (mostly European) then need to be reduced by 30-50% from the a priori value of 68 Tg yr -1. The decrease of European sources could result in part from recent mitigation of emissions from coal mining and landfills. Copyright 2004 by the American Geophysical Union
Greenland subglacial lakes detected by radar
This is the final version of the article. Available from AGU via the DOI in this record.Subglacial lakes are an established and important component of the basal hydrological system of the Antarctic ice sheets, but none have been reported from Greenland. Here we present airborne radio echo sounder (RES) measurements that provide the first clear evidence for the existence of subglacial lakes in Greenland. Two lakes, with areas ~8 and ~10 km2, are found in the northwest sector of the ice sheet, ~40 km from the ice margin, and below 757 and 809 m of ice, respectively. The setting of the Greenland lakes differs from those of Antarctic subglacial lakes, being beneath relatively thin and cold ice, pointing to a fundamental difference in their nature and genesis. Possibilities that the lakes consist of either ancient saline water in a closed system or are part of a fresh, modern open hydrological system are discussed, with the latter interpretation considered more likely.Funding was provided by NERC grant NE/
H020667. Additional support was provided by NASA grant NNX11AD33G
and the G. Unger Vetlesen foundation
Global expansion of Vibrio parahaemolyticus threatens the seafood industry: Perspective on controlling its biofilm formation
As global warming increases the geographical range and frequency of Vibrio parahaemolyticus infections, its formation of biofilms providing bacteria greater resistance to stress and contributing to the persistence of pathogens, is threatening the seafood industry. V. parahaemolyticus has a number of advantages leading to biofilm formation. This study reviews recent advances in understanding V. parahaemolyticus biofilm formation on biotic and abiotic surfaces, discusses research gaps in the mechanism of biofilm formation and examines promising biofilm control strategies to overcome current limitations of chemical disinfectant. This information will deepen our understanding of V. parahaemolyticus biofilm formation, as well as help design and optimize V. parahaemolyticus biofilm control strategies for the seafood industry
Determinants of adults' intention to vaccinate against pandemic swine flu
This article has been made available through the Brunel Open Access Publishing Fund.This article has been made available through the Brunel Open Access Publishing Fund.Background: Vaccination is one of the cornerstones of controlling an influenza pandemic. To optimise vaccination rates in the general population, ways of identifying determinants that influence decisions to have or not to have a vaccination need to be understood. Therefore, this study aimed to predict intention to have a swine influenza
vaccination in an adult population in the UK. An extension of the Theory of Planned Behaviour provided the theoretical framework for the study.
Methods: Three hundred and sixty two adults from the UK, who were not in vaccination priority groups, completed either an online (n = 306) or pen and paper (n = 56) questionnaire. Data were collected from 30th October 2009, just after swine flu vaccination became available in the UK, and concluded on 31st December 2009. The main outcome of interest was future swine flu vaccination intentions.
Results: The extended Theory of Planned Behaviour predicted 60% of adults’ intention to have a swine flu vaccination with attitude, subjective norm, perceived control, anticipating feelings of regret (the impact of missing a vaccination opportunity), intention to have a seasonal vaccine this year, one perceived barrier: “I cannot be bothered to get a swine flu vaccination” and two perceived benefits: “vaccination decreases my chance of getting swine flu or its complications” and “if I get vaccinated for swine flu, I will decrease the frequency of having to consult my doctor,” being significant predictors of intention. Black British were less likely to intend to have a vaccination compared to Asian or White respondents.
Conclusions: Theoretical frameworks which identify determinants that influence decisions to have a pandemic influenza vaccination are useful. The implications of this research are discussed with a view to maximising any future pandemic influenza vaccination uptake using theoretically-driven applications.This article is available through the Brunel Open Access Publishing Fund
Reduction of low- and high-grade cervical abnormalities associated with high uptake of the HPV bivalent vaccine in Scotland
In Scotland, a national HPV immunisation programme began in 2008 for 12-13 year olds, with a catch-up campaign from 2008-2011 for those under the age of 18. To monitor the impact of HPV immunisation on cervical disease at the population level, a programme of national surveillance was established. We analysed colposcopy data from a cohort of women born between 1988-1992 who entered the Scottish Cervical Screening Programme (SCSP) and were aged 20-21 in 2008-2012. By linking datasets from the SCSP and colposcopy services, we observed a significant reduction in diagnoses of cervical intraepithelial neoplasia 1 (CIN 1) (RR 0.71, 95% CI 0.58 to 0.87, p=0.0008), CIN 2 (RR 0.5, 95% CI 0.4, 0.63, p<0.0001) and CIN 3 (RR 0.45, 95% CI 0.35 to 0.58, p< 0.0001) for women who received 3 doses of vaccine compared with unvaccinated women. To our knowledge, this is one of the first studies to show a reduction of low and high grade cervical intraepithelial neoplasia associated with high uptake of the HPV bivalent vaccine at the population level. These data are very encouraging for countries that have achieved high HPV vaccine uptake
Genetic Variation in the Complete MgPa Operon and Its Repetitive Chromosomal Elements in Clinical Strains of Mycoplasma genitalium
Mycoplasma genitalium has been increasingly recognized as an important microbe not only because of its significant association with human genital tract diseases but also because of its utility as a model for studying the minimum set of genes necessary to sustain life. Despite its small genome, 4.7% of the total genome sequence is devoted to making the MgPa adhesin operon and its nine chromosomal repetitive elements (termed MgPars). The MgPa operon, along with 9 MgPars, is believed to play an important role in pathogenesis of M. genitalium infection and has also served as the main target for development of diagnostic tools. However, genetic variation in the complete MgPa operon and MgPars among clinical strains of M. genitalium has not been addressed. In this study we examined the genetic variation in the complete MgPa operon (approximately 8.5 kb) and full or partial MgPar sequences (0.4–2.6 kb) in 15 geographically diverse strains of M. genitalium. Extensive variation was present in four repeat regions of the MgPa operon (with homology to MgPars) among and within strains while the non-repeat regions (without homology to MgPars) showed low-level variation among strains and no variation within strains. MgPars showed significant variation among strains but were highly homogeneous within strains, supporting gene conversion as the likely recombination mechanism. When applying our sequence data to evaluate published MgPa operon-based diagnostic PCR assays and genotyping systems, we found that 11 of 19 primers contain up to 19 variable nucleotides and that the target for one of two typing systems is located in a hypervariable repeat region, suggesting the likelihood of false results with some of these assays. This study not only provides new insights into the role of the MgPa operon in the pathogenesis of M. genitalium infection but has important implications for the development of diagnostic tools
Old Stellar Populations in Nearby Dwarf Galaxies
What can we learn from the somewhat arduous study of old stellar populations in nearby galaxies? Unless the nearby universe is subtly anomalous, it should contain a relatively normal selection of galaxies whose histories are representative of field galaxies in general throughout the Universe. We can therefore take advantage of our ability to resolve local galaxies into individual stars to directly, and accurately, measure star formation histories. The star formation histories are determined from numerical models, based on stellar evolution tracks, of colour-magnitude diagrams. The most accurate information on star formation rates extending back to the earliest epoches can be obtained from the structure of the main sequence. However, the oldest main sequence turnoffs are very faint, and it is often necessary to use the brighter, more evolved, populations to infer the star formation history at older times. A complete star formation history can be compared with the spectroscopic properties of galaxies seen over a large range of lookback times in redshift surveys. There is considerable evidence that the faint blue galaxies seen in large numbers in cosmological surveys are the progenitors of the late-type irregular galaxies seen in copious numbers in the Local Group, and beyond. We consider how the ``Madau-diagram'', the star formation history of the Universe, would look if the Local Group were to be considered representative of the Universe as a whole
Primary gastric tuberculosis – report of 5 cases
BACKGROUND: Gastric tuberculosis is rare, and usually associated with pulmonary tuberculosis or an immunodeficient state. Here, we report five cases of gastric tuberculosis in immunocompetent patients without evidence of pulmonary involvement. CASE PRESENTATION: Three patients presented with gastric outlet obstruction that required surgery to relieve the obstruction as well as to confirm the diagnosis. The remaining two had involvement of gastroesophageal junction. All of them responded well to standard antitubercular treatment. CONCLUSION: Though gastric tuberculosis is rare, it should be considered a possibility when patients present with gastric outlet obstruction or with endoscopic evidence of diffuse chronic inflammatory activity, particularly in areas endemic for tuberculosis
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