3,122 research outputs found

    Leptogenesis after Chaotic Sneutrino Inflation and the Supersymmetry Breaking Scale

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    We discuss resonant leptogenesis arising from the decays of two nearly-degenerate right-handed neutrinos, identified as the inflaton and stabiliser superfields in a model of chaotic sneutrino inflation. We compare an analytical estimate of the baryon asymmetry ηB \eta_B in the Boltzmann approximation to a numerical solution of the full density matrix equations, and find that the analytical result fails to capture the correct physics in certain regions of parameter space. The observed baryon asymmetry can be realised for a breaking of the mass degeneracy as small as O(108) \mathcal{O}(10^{-8}) . The origin of such a small mass splitting is explained by considering supersymmetry (SUSY) breaking in supergravity, which requires a constant in the superpotential of the order of the gravitino mass m3/2 m_{3/2} to cancel the cosmological constant. This yields additional terms in the (s)neutrino mass matrices, lifting the degeneracy and linking ηB \eta_B to the SUSY breaking scale. We find that achieving the correct baryon asymmetry requires a gravitino mass m3/2O(100) m_{3/2} \geq \mathcal{O}(100) TeV.Comment: v2: 25 pages, 4 figures; version published in NPB, minor corrections. v1: 24 pages, 4 figure

    Bedrock Geology and Sea-Level History of Fayetteville Quadrangle, Washington County, Arkansas

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    A digital map depicting the detailed bedrock geology of Fayetteville Quadrangle, Washington County, Arkansas was produced at 1:24,000 scale. This map was developed utilizing state-of-the-art Geographic Information Systems technology and represents the most detailed map of the geology of Fayetteville Quadrangle that has been produced. In addition, the stratigraphy was interpreted to develop a regional sea-level history for the quadrangle. The bedrock geology of Fayetteville Quadrangle consists of sedimentary rocks of the Mississippian and Pennsylvanian systems. The Mississippian System is represented by (in ascending order) the Boone, Batesville, Fayetteville, and Pitkin Formations. The Pennsylvanian System is represented by (in ascending order) the Hale, Bloyd, and Atoka Formations. Each of these formations has members that were mapped at 1:24,000 scale, with the exception of the Hindsville Member of the Batesville Formation. Depositional environments represented by Fayetteville Quadrangle strata range from shallow marine to terrestrial and were interpreted to reflect the interplay of tectonics and eustasy during the Mississippian-Pennsylvanian Periods. Analysis of the apparent tempo and amplitude of sea-level variations suggests tectonic processes dominated over eustatic processes during these times. Within Fayetteville Quadrangle there are also several geologic structures that deserve further investigation. These structures include faults, fractures, domes, and so-called collapse or subsidence structures

    Bedrock Geology of West Fork Quadrangle, Washington County, Arkansas

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    A digital geologic map of West Fork quadrangle was produced at 1:24,000 scale using the geographic information system (GIS) software Maplnfo. Data regarding stratigraphic relations observed in the field were digitized onto the United States Geological Survey (USGS) digital raster graphic (DRG) of West Fork quadrangle. The geology of West Fork quadrangle consists of sedimentary rocks of the Mississippian and Pennsylvanian systems. The Fayetteville Shale and Pitkin Formation represent the Mississippian system. The Hale, Bloyd, and Atoka Formations represent the Pennsylvanian System. Each of these formations consists of members that were mapped at 1:24,000 scale, and this mapping effort represents the first time stratigraphic members were mapped utilizing digital technologies at this scale in West Fork quadrangle. The Hale Formation consists of the Cane Hill Member and the Prairie Grove Member. The Bloyd Formation consists of the Brentwood Member, the Woolsey Member, the Dye Member, and the Kessler Member. The Atoka Formation in West Fork quadrangle includes the Trace Creek Member at its base. The overlying units of the Atoka Formation occur as unnamed alternating sandstone and shale units. The most prominent geologic structure in West Fork quadrangle is the Fayetteville Fault, which crosses the northwest quarter of the quadrangle. Several additional faults are associated with a fault zone surrounding the Fayetteville Fault. Another prominent normal fault was mapped striking east-west (downthrown to the south) in the southern part of the quadrangle

    Stomatal Conductance of Malosma laurina in Frequently Burned and Non-frequently Burned Sites

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    In the months following the Malibu fires, the fire zones have experienced and abundance of new growth. Among this new growth, there are differences that can be observed when comparing the top of the Malibu hill (frequent fire zone) to the base of the hill (nonfrequent fire zone). As the chaparral resprouted we noticed the behavior of the Malosma laurina in both frequent and non-frequent fire zones and stomatal conductance, height, and water potential were tested for plants in the two varying zones, with plants in the non-frequent fire zone outperforming their counterparts

    Raised immunoglobulin E and idiopathic bronchiectasis

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    SummaryWe describe a series of 4 subjects with markedly raised immunoglobulin E levels in association with idiopathic bronchiectasis. This has not been described previously and appears to be a distinct entity from other conditions such as allergic bronchopulmonary aspergillosis

    Occurrence and Severity of the Viruses of Strawberry in Minnesota

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    Approximately 900 plants of commercially grown strawberries of 45 varieties and experimental seedling selections were collected from various parts of the state of Minnesota and indexed for the presence of viruses. Their presence in these plants was demonstrated by the appearance of symptoms in the indicator plant, Fragaria vesca L., after they were inarch-grafted. 93 % of the plants indexed were virus-infected. Based on symptoms, the viruses have been classified into 14 symptomtypes. It was found that mottle and mild yellow-edge were the two dominant viruses, whereas crinkle and vein chlorosis were of rare occurrence. There was no indication that certain symptom-types are associated with particular commercial varieties of strawberries or experimental seedling selections

    Trimaximal neutrino mixing from vacuum alignment in A4 and S4 models

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    Recent T2K results indicate a sizeable reactor angle theta_13 which would rule out exact tri-bimaximal lepton mixing. We study the vacuum alignment of the Altarelli-Feruglio A4 family symmetry model including additional flavons in the 1' and 1" representations and show that it leads to trimaximal mixing in which the second column of the lepton mixing matrix consists of the column vector (1,1,1)^T/sqrt{3}, with a potentially large reactor angle. In order to limit the reactor angle and control the higher order corrections, we propose a renormalisable S4 model in which the 1' and 1" flavons of A4 are unified into a doublet of S4 which is spontaneously broken to A4 by a flavon which enters the neutrino sector at higher order. We study the vacuum alignment in the S4 model and show that it predicts accurate trimaximal mixing with approximate tri-bimaximal mixing, leading to a new mixing sum rule testable in future neutrino experiments. Both A4 and S4 models preserve form dominance and hence predict zero leptogenesis, up to renormalisation group corrections.Comment: 24 pages, 2 figures, version to be published in JHE

    Microbiologic follow-up study in adult bronchiectasis

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    SummaryThere is minimal published longitudinal data about pathogenic microorganisms in adults with bronchiectasis. Therefore a study was undertaken to assess the microbiologic profile over time in bronchiectasis.A prospective study of clinical and microbiologic outcomes was performed. Subjects were assessed by a respiratory physician and sputum sample were collected for analysis. Subjects were followed up and had repeat assessment performed.Eighty-nine subjects were followed up for a period of 5.7±3.6 years. On initial assessment the two most common pathogens isolated were Haemophilus influenzae (47%) and Pseudomonas aeruginosa (12%) whilst 21% had no pathogens isolated. On follow-up review results were similar (40% H. influenzae, 18% P. aeruginosa and 26% no pathogens). The prevalence of antibiotic resistance of isolates increased from 13% to 30%. Analysis of a series of H. influenzae isolates showed they were nearly all nontypeable and all were different subtypes. Subjects with no pathogens isolated from their sputum had the mildest disease, while subjects with P. aeruginosa had the most severe bronchiectasis.Many subjects with bronchiectasis are colonized with the same bacterium over an average follow-up of 5 years. Different pathogens are associated with different patterns of clinical disease
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