190 research outputs found

    A summary of the methodology for the seismic stratigraphic interpretation for the 'GlaciStore' bid to IODP

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    This report summarises the methodology followed for the seismic interpretation of sedimentary strata that are the overburden sequence and the Palaeogene strata that are prospective CO2 storage formations, in the UK Central North Sea. The interpretation of selected 2D and 3D seismic reflection, well and borehole data in the UK North and Central North Sea is targeted to inform the preparation of the ‘GlaciStore’ proposal for scientific drilling submitted to the International Ocean Discovery Programme (IODP). Drilling sites proposed to IODP lie within the UK and Norwegian sectors of the North Sea. The methodology is described for the interpretation of seismic data for proposed sites within UK waters. The seismic interpretation was undertaken in collaboration with Norwegian members of the GlaciStore consortium. The seismic interpretation was divided into two teams according to depth, into ‘shallower and ‘deeper’ seismic interpretation activities, appropriate to the fields of expertise and experience of the interpreters. The ‘shallower seismic’ interpreters considered strata of latest Neogene and Quaternary age which were deposited during major glacial and interglacial cycles. The ‘deeper seismic’ interpreters considered slightly older strata of Mid Eocene to Quaternary in age. Seven potential UK drill sites were selected to address the scientific objectives in the proposal. 2D and 3D seismic, well, borehole and bathymetry data were used to map buried and open tunnel valleys and to identify any evidence for the presence of shallow gas in the ‘shallower seismic’ interpretation at each drill site. Only sites without any indication of shallow gas features were considered as these pose a serious hazard for drilling. 2D and 3D seismic and well datasets and existing interpretations were collated for the ‘deeper seismic’ interpretation. The hydrocarbon exploration well log data, which were found to be of variable quality, were used to identify and map a number of stratigraphical surfaces of Cenozoic age, and included Quaternary strata, around the grid of seismic lines. Maps from some of the key stratigraphical surfaces are presented, selected to inform the drilling proposal. A plot of acoustic velocity data was prepared to inform future conversion of the seismic interpretation to true vertical depth. Future work, based on the seismic interpretation undertaken to underpin the drilling proposal, is identified. Features observed within the ‘shallower’ and ‘deeper’ seismic interpretations that warrant further investigation are: a chaotic zone within the Quaternary sequence; prograding units within the Eocene Horda Formation; basin centre sandstone bodies as prospective CO2 storage strata within the Horda Formation; systematic mapping of cross-cutting, buried tunnel valleys in the Quaternary sequence from 3D seismic data

    On The Low Frequency Quasi Periodic Oscillations of X-ray Sources

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    Based on the interpretation of the twin kilohertz Quasi Periodic Oscillations (kHz QPOs) of X-ray spectra of Low Mass X-Ray Binaries (LMXBs) to the Keplerian and the periastron precession frequencies at the magnetosphere-disk of X-ray neutron star (NS) respectively, we ascribe the low frequency Quasi Periodic Oscillations (LFQPO) and HBO (15-60 Hz QPO for Z sources or Atoll sources) to the periastron precession at some outer disk radius. The obtained conclusions include: all QPO frequencies increase with increasing the accretion rate. The obtained theoretical relations between HBO (LFQPO) frequency and the kHz QPO frequency are similar to the measured empirical formula. Further, the possible dynamical mechanism for QPO production is discussed.Comment: 6 pages, 2 figures, accepted by APSS, 200

    Are the magnetic fields of millisecond pulsars ~ 10^8 G?

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    It is generally assumed that the magnetic fields of millisecond pulsars (MSPs) are ∌108\sim 10^{8}G. We argue that this may not be true and the fields may be appreciably greater. We present six evidences for this: (1) The ∌108\sim 10^{8} G field estimate is based on magnetic dipole emission losses which is shown to be questionable; (2) The MSPs in low mass X-ray binaries (LMXBs) are claimed to have <1011< 10^{11} G on the basis of a Rayleygh-Taylor instability accretion argument. We show that the accretion argument is questionable and the upper limit 101110^{11} G may be much higher; (3) Low magnetic field neutron stars have difficulty being produced in LMXBs; (4) MSPs may still be accreting indicating a much higher magnetic field; (5) The data that predict ∌108\sim 10^{8} G for MSPs also predict ages on the order of, and greater than, ten billion years, which is much greater than normal pulsars. If the predicted ages are wrong, most likely the predicted ∌108\sim 10^{8} G fields of MSPs are wrong; (6) When magnetic fields are measured directly with cyclotron lines in X-ray binaries, fields ≫108\gg 10^{8} G are indicated. Other scenarios should be investigated. One such scenario is the following. Over 85% of MSPs are confirmed members of a binary. It is possible that all MSPs are in large separation binaries having magnetic fields >108> 10^{8} G with their magnetic dipole emission being balanced by low level accretion from their companions.Comment: 16 pages, accept for publication in Astrophysics and Space Scienc

    Epidermal Notch1 recruits RORÎł+ group 3 innate lymphoid cells to orchestrate normal skin repair

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    Notch has a well-defined role in controlling cell fate decisions in the embryo and the adult epidermis and immune systems, yet emerging evidence suggests Notch also directs non-cell-autonomous signalling in adult tissues. Here, we show that Notch1 works as a damage response signal. Epidermal Notch induces recruitment of immune cell subsets including RORγ + ILC3s into wounded dermis; RORγ + ILC3s are potent sources of IL17F in wounds and control immunological and epidermal cell responses. Mice deficient for RORγ + ILC3s heal wounds poorly resulting from delayed epidermal proliferation and macrophage recruitment in a CCL3-dependent process. Notch1 upregulates TNFα and the ILC3 recruitment chemokines CCL20 and CXCL13. TNFα, as a Notch1 effector, directs ILC3 localization and rates of wound healing. Altogether these findings suggest that Notch is a key stress/injury signal in skin epithelium driving innate immune cell recruitment and normal skin tissue repair

    The Muonium Atom as a Probe of Physics beyond the Standard Model

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    The observed interactions between particles are not fully explained in the successful theoretical description of the standard model to date. Due to the close confinement of the bound state muonium (M=ÎŒ+e−M = \mu^+ e^-) can be used as an ideal probe of quantum electrodynamics and weak interaction and also for a search for additional interactions between leptons. Of special interest is the lepton number violating process of sponteanous conversion of muonium to antimuonium.Comment: 15 pages,6 figure

    Forced oscillations in a hydrodynamical accretion disk and QPOs

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    This is the second of a series of papers aimed to look for an explanation on the generation of high frequency quasi-periodic oscillations (QPOs) in accretion disks around neutron star, black hole, and white dwarf binaries. The model is inspired by the general idea of a resonance mechanism in the accretion disk oscillations as was already pointed out by Abramowicz & Klu{\'z}niak (\cite{Abramowicz2001}). In a first paper (P\'etri \cite{Petri2005a}, paper I), we showed that a rotating misaligned magnetic field of a neutron star gives rise to some resonances close to the inner edge of the accretion disk. In this second paper, we suggest that this process does also exist for an asymmetry in the gravitational potential of the compact object. We prove that the same physics applies, at least in the linear stage of the response to the disturbance in the system. This kind of asymmetry is well suited for neutron stars or white dwarfs possessing an inhomogeneous interior allowing for a deviation from a perfectly spherically symmetric gravitational field. We show by a linear analysis that the disk initially in a cylindrically symmetric stationary state is subject to three kinds of resonances: a corotation resonance, a Lindblad resonance due to a driven force and a parametric sonance. The highest kHz QPOs are then interpreted as the orbital frequency of the disk at locations where the response to the resonances are maximal. It is also found that strong gravity is not required to excite the resonances.Comment: Accepte

    Modelling phenolic and technological maturities of grapes by means of the multivariate relation between organoleptic and physicochemical properties

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    The ripeness of grapes at the harvest time is one of the most important parameters for obtaining high quality red wines. Traditionally the decision of harvesting is to be taken only after analysing sugar concentration, titratable acidity and pH of the grape juice (technological maturity). However, these parameters only provide information about the pulp ripeness and overlook the real degree of skins and seeds maturities (phenolic maturity). Both maturities, technological and phenolic, are not simultaneously reached, on the contrary they tend to separate depending on several factors: grape variety, cultivar, adverse weather conditions, soil, water availability and cultural practices. Besides, this divergence is increasing as a consequence of the climate change (larger quantities of CO2, less rain, and higher temperatures). 247 samples collected in vineyards representative of the qualified designation of origin Rioja from 2007 to 2011 have been analysed. Samples contain the four grape varieties usual in the elaboration of Rioja wines (‘tempranillo’, ‘garnacha’, ‘mazuelo’ and ‘graciano’). The present study is the first systematic investigation on the maturity of grapes that includes the organoleptic evaluation of the degree of grapes maturity (sugars/acidity maturity, aromatic maturity of the pulp, aromatic maturity of the skins and tannins maturity) together with the values of the physicochemical parameters (probable alcohol degree, total acidity, pH, malic acid, K, total index polyphenolics, anthocyans, absorbances at 420, 520 and 620 nm, colour index and tartaric acid) determined over the same samples. A varimax rotation of the latent variables of a PLS model between the physicochemical variables and the mean of four sensory variables allows identifying both maturities. Besides, the position of the samples in the first plane defines the effect that the different factors exert on both phenolic and technological maturitiesMinisterio de Economía y Competitividad (CTQ2011-26022) and Junta de Castilla y León (BU108A11-2
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