1,189 research outputs found

    Gravitational Collapse of Null Radiation and a String fluid

    Get PDF
    We consider the end state of collapsing null radiation with a string fluid. It is shown that, if diffusive transport is assumed for the string, that a naked singularity can form (at least locally). The model has the advantage of not being asymptotically flat. We also analyse the case of a radiation-string two-fluid and show that a locally naked singularity can result in the collapse of such matter. We contrast this model with that of strange quark matter.Comment: RevTeX 4.0 (8 pages - no figures). submitted to Phys Rev D. Some changes to abstract, introduction and conclusion - references update

    Flavor Alignment Solutions to the Strong CP Problem in Supersymmetry

    Get PDF
    An approach to solving the Strong CP Problem in supersymmetric theories is discussed which uses abelian family symmetries to align the mass matrices of the quarks and squarks. In this way both the Strong CP Problem and the characteristic flavor and CP problems of supersymmetry can be solved in a single way.Comment: 13 pages, LaTe

    The effect of SU-8 patterned surfaces on the response of the quartz crystal microbalance

    Get PDF
    In this work we present data showing the effect of patterning layers of SU-8 photoresist on a quartz crystal microbalance (QCM) and subsequent chemical treatment to increase their hydrophobicity. Patterns with 5 mu m diameter pillars spaced every 10 mu m have been fabricated with heights of 3, 5 and 10 mu m in addition to equivalent thickness flat layers. Contact angle measurements have been made before and after the hydrophobic chemical treatment. The change in resonant frequency of the QCM has been investigated as the surfaces were submerged in solutions of water/PEG with changing viscosity-density product

    Constrained Supersymmetric Flipped SU(5) GUT Phenomenology

    Full text link
    We explore the phenomenology of the minimal supersymmetric flipped SU(5) GUT model (CFSU(5)), whose soft supersymmetry-breaking (SSB) mass parameters are constrained to be universal at some input scale, MinM_{in}, above the GUT scale, MGUTM_{GUT}. We analyze the parameter space of CFSU(5) assuming that the lightest supersymmetric particle (LSP) provides the cosmological cold dark matter, paying careful attention to the matching of parameters at the GUT scale. We first display some specific examples of the evolutions of the SSB parameters that exhibit some generic features. Specifically, we note that the relationship between the masses of the lightest neutralino and the lighter stau is sensitive to MinM_{in}, as is the relationship between the neutralino mass and the masses of the heavier Higgs bosons. For these reasons, prominent features in generic (m1/2,m0)(m_{1/2}, m_0) planes such as coannihilation strips and rapid-annihilation funnels are also sensitive to MinM_{in}, as we illustrate for several cases with tan(beta)=10 and 55. However, these features do not necessarily disappear at large MinM_{in}, unlike the case in the minimal conventional SU(5) GUT. Our results are relatively insensitive to neutrino masses.Comment: 23 pages, 8 figures; (v2) added explanations and corrected typos, version to appear in EPJ

    Colliders and Cosmology

    Full text link
    Dark matter in variations of constrained minimal supersymmetric standard models will be discussed. Particular attention will be given to the comparison between accelerator and direct detection constraints.Comment: Submitted for the SUSY07 proceedings, 15 pages, LaTex, 26 eps figure

    Strangeness in constituent quarks and one-spin asymmetry in inclusive φ\varphi-meson production

    Get PDF
    On the basis of the mechanism proposed earlier for one-spin asymmetries in inclusive hadron production we consider OZI--suppressed process of φ\varphi-meson production pp→φXpp\rightarrow \varphi X and asymmetry AN(φ)A_N(\varphi) in this process. The main role in generation of this asymmetry belongs to the orbital angular momentum of strange quark-antiquark cloud in internal structure of constituent quarks.Comment: 8 pages, plain LaTeX, no figure

    High-throughput, automated quantification of white matter neurons in mild malformation of cortical development in epilepsy

    Get PDF
    Introduction In epilepsy, the diagnosis of mild Malformation of Cortical Development type II (mMCD II) predominantly relies on the histopathological assessment of heterotopic neurons in the white matter. The exact diagnostic criteria for mMCD II are still ill-defined, mainly because findings from previous studies were contradictory due to small sample size, and the use of different stains and quantitative systems. Advance in technology leading to the development of whole slide imaging with high-throughput, automated quantitative analysis (WSA) may overcome these differences, and may provide objective, rapid, and reliable quantitation of white matter neurons in epilepsy. This study quantified the density of NeuN immunopositive neurons in the white matter of up to 142 epilepsy and control cases using WSA. Quantitative data from WSA was compared to two other systems, semi-automated quantitation, and the widely accepted method of stereology, to assess the reliability and quality of results from WSA. Results All quantitative systems showed a higher density of white matter neurons in epilepsy cases compared to controls (P = 0.002). We found that, in particular, WSA with user-defined region of interest (manual) was superior in terms of larger sampled size, ease of use, time consumption, and accuracy in region selection and cell recognition compared to other methods. Using results from WSA manual, we proposed a threshold value for the classification of mMCD II, where 78% of patients now classified with mMCD II were seizure-free at the second post-operatively follow up. Conclusion This study confirms the potential role of WSA in future quantitative diagnostic histology, especially for the histopathological diagnosis of mMCD

    Threatened, endemic and harvested – two overlooked European skates

    Get PDF
    Sandy ray Leucoraja circularis and shagreen ray L. fullonica are large-bodied skate species occurring in the Northeast Atlantic and Mediterranean on the edge of the continental shelf and upper slope. These areas are not sampled effectively by fishery-independent trawl surveys, and fisheries-dependent data are also limited, as these species are landed as a bycatch. Consequently, there are no formal assessments or reference points, even though they are harvested as part of the Total Allowable Catch (TAC) for generic skates and rays. The implementation of data-limited assessment methods is often reliant on robust life-history data, which was lacking. Therefore, biological data were collected from 116 specimens of L. circularis (21–116 cm LT) and 54 specimens of L. fullonica (19–100 cm LT). Length at 50% maturity for L. circularis was estimated at 81 cm LT and 100 cm LT for males and females, respectively. This large size at maturity makes them more biologically vulnerable than other skate species managed under the generic TAC. This inherent vulnerability, low representation of mature individuals in trawl surveys and bycatch risk due to spatial overlap with important commercial fisheries suggests that both species, assessed as Threatened, would benefit from precautionary species-specific management measures. L. circularis and L. fullonica are respectively, the only IUCN listed Endangered and Vulnerable elasmobranchs that are endemic to Europe and also occur in UK waters. Therefore, with the eastern Atlantic being the main part of their distribution, urgent research and management action is of even greater importance to conserve them

    Risk Assessment of E. coli Survival Up to the Grazing Exclusion Period After Dairy Slurry, Cattle Dung, and Biosolids Application to Grassland

    Get PDF
    peer-reviewedGrassland application of dairy slurry, cattle dung, and biosolids offers an opportunity to recycle valuable nutrients (N, P, and K), which may all introduce pathogens to the soil environment. Herein, a temporal risk assessment of the survival of Escherichia coli (E. coli) up to 40 days in line with the legislated grazing exclusion time points after application was examined across six scenarios: (1) soil and biosolids mixture, (2) biosolids amended soil, (3) dairy slurry application, (4) cattle dung on pasture, (5) comparison of scenario 2, 3, and 4, and (6) maximum legal vs. excess rate of application for scenario 2 and 3. The risk model input parameters were taken or derived from regressions within the literature and an uncertainty analysis (n = 1,000 trials for each scenario) was conducted. Scenario 1 results showed that E. coli survival was higher in the soil/biosolids mixture for higher biosolids portion, resulting in the highest 20 day value of residual E. coli concentration (i.e., C20, log10 CFU g−1 dw) of 1.0 in 100% biosolids or inoculated soil and the lowest C20 of 0.098 in 75/25 soil/biosolids ratio, respectively, in comparison to an average initial value of ~6.4 log10 CFU g−1 dw. The E. coli survival across scenario 2, 3, and 4 showed that the C20 value of biosolids (0.57 log10 CFU g−1 dw) and dairy slurry (0.74 log10 CFU ml−1) was 2.9–3.7 times smaller than that of cattle dung (2.12 log10 CFU g−1 dw). The C20 values of biosolids and dairy slurry associated with legal and excess application rates ranged from 1.14 to 1.71 log10 CFU ha−1, which is a significant reduction from the initial concentration range (12.99 to 14.83 log10 CFU ha−1). The E. coli survival in un-amended soil was linear with a very low decay rate resulting in a higher C20 value than that of biosolids or dairy slurry. The risk assessment and uncertainly analysis showed that the residual concentrations in biosolids/dairy slurry applied soil after 20 days would be 45–57% lower than that of the background soil E. coli concentration. This means the current practice of grazing exclusion times is safe to reduce the risk of E. coli transmission into the soil environment.This publication has emanated from research funded by the EU FP7 Environment theme–Grant no. 265269 Marketable sludge derivatives from a highly integrated wastewater treatment plant (END-O-SLUDG)

    A panoramic mid-infrared survey of two distant clusters

    Get PDF
    We present panoramic Spitzer MIPS 24 ÎŒm observations, covering ~9 × 9 Mpc2 (25' × 25') fields around two massive clusters, Cl 0024+16 and MS 0451-03, at z = 0.39 and z = 0.55, respectively, reaching a 5 σ flux limit of ~200 ÎŒJy. Our observations cover a very wide range of environments within these clusters, from high-density regions around the cores out to the turnaround radius. Cross-correlating the mid-infrared catalogs with deep optical and near-infrared imaging of these fields, we investigate the optical/near-infrared colors of the mid-infrared sources. We find excesses of mid-infrared sources with the optical/near-infrared colors expected of cluster members in the two clusters and test this selection using spectroscopically confirmed 24 ÎŒm members. The much more significant excess is associated with Cl 0024+16, whereas MS 0451-03 has comparatively few mid-infrared sources. The mid-infrared galaxy population in Cl 0024+16 appears to be associated with dusty star-forming galaxies (typically redder than the general cluster population by up to AV ~ 1-2 mag) rather than emission from dusty tori around active galactic nuclei in early-type hosts. We compare the star formation rates derived from the total infrared (8-1000 ÎŒm) luminosities for the mid-infrared sources in Cl 0024+16 with those estimated from a published Hα survey, finding rates 5 times those found from Hα, indicating significant obscured activity in the cluster population. Compared to previous mid-infrared surveys of clusters from z ~ 0-0.5, we find evidence for strong evolution of the level of dust-obscured star formation in dense environments to z = 0.5, analogous to the rise in the fraction of optically selected star-forming galaxies seen in clusters and the field out to similar redshifts. However, there are clearly significant cluster-to-cluster variations in the populations of mid-infrared sources, probably reflecting differences in the intracluster media and recent dynamical evolution of these systems
    • 

    corecore