59,648 research outputs found
A new look at the pathogenesis of asthma
No full textAsthma is an inflammatory disorder of the conducting airways that has strong association with allergic sensitization. The disease is characterized by a polarized Th-2 (T-helper-2)-type T-cell response, but in general targeting this component of the disease with selective therapies has been disappointing and most therapy still relies on bronchodilators and corticosteroids rather than treating underlying disease mechanisms. With the disappointing outcomes of targeting individual Th-2 cytokines or manipulating T-cells, the time has come to re-evaluate the direction of research in this disease. A case is made that asthma has its origins in the airways themselves involving defective structural and functional behaviour of the epithelium in relation to environmental insults. Specifically, a defect in barrier function and an impaired innate immune response to viral infection may provide the substrate upon which allergic sensitization takes place. Once sensitized, the repeated allergen exposure will lead to disease persistence. These mechanisms could also be used to explain airway wall remodelling and the susceptibility of the asthmatic lung to exacerbations provoked by respiratory viruses, air pollution episodes and exposure to biologically active allergens. Variable activation of this epithelial-mesenchymal trophic unit could also lead to the emergence of different asthma phenotypes and a more targeted approach to the treatment of these. It also raises the possibility of developing treatments that increase the lung's resistance to the inhaled environment rather than concentrating all efforts on trying to suppress inflammation once it has become established.<br/
Measurement of the ratio of prompt χ c to J / ψ production in pp collisions at √s = 7 TeV
No full textThe prompt production of charmonium χ c and J / ψ states is studied in proton-proton collisions at a centre-of-mass energy of √s = 7 TeV at the Large Hadron Collider. The χ c and J / ψ mesons are identified through their decays χ c → J / ψ γ and J / ψ → μ + μ - using 36 pb - 1 of data collected by the LHCb detector in 2010. The ratio of the prompt production cross-sections for χ c and J / ψ, σ (χ c → J / ψ γ) / σ (J / ψ), is determined as a function of the J / ψ transverse momentum in the range 2 < p T J / ψ < 15 GeV / c. The results are in excellent agreement with next-to-leading order non-relativistic expectations and show a significant discrepancy compared with the colour singlet model prediction at leading order, especially in the low p T J / ψ region
δ Orionis: Further temporal variability and evidence for small-scale structure in the interstellar medium
No full textWe report here the detection of both spatial and temporal variations in interstellar absorption in the line of sight to δ Orionis. First, we present new high-resolution (R≈110 000) observations of the interstellar D lines of Na i towards both δ Ori A and C. Comparison of these spectra highlights variations in absorption between the two stars, indicative of small-scale spatial structure in the interstellar medium in this direction over distances of less than ≈15 000 au (the projected separation of the two stars). Components with the largest Na i column densities and lowest velocity dispersions are, in general, found to be subject to the greatest differences; in fact the narrowest component detected is only observed in one of the sightlines. This effect has also been reported by Meyer & Blades. Secondly, we present new ultra-high-resolution (R≈900 000) Na i D1 observations and high-resolution (R≈110 000) Ca ii H & K observations of δ Ori A which, through ultra-high-resolution work conducted between 1994 and 2000, has been shown to exhibit a time-variable interstellar Na i absorption component. These new observations, while revealing the further reduction in intensity of the time-variable Na i absorption, indicate constant Ca ii absorption over the same period. This results in a dramatic reduction in the Na°/Ca+ abundance ratio, perhaps indicating the line of sight to be gradually probing a less-dense outer region of an absorbing filament
Josephiella Matsunaga & Howarth & Kumashiro 2019, n. sp.
No full text<i>Josephiella</i> n. sp. A (apparently undescribed) <p> <b>NEW STATE RECORD</b></p> <p> An agaonid wasp new to science was discovered causing galls on the stems of <i>Ficus microcarpa</i>. Terminal stems of affected trees appeared unhealthy with a sparse foliar canopy. Initial observers of this damage were under the assumption that the same species which causes leaf galling on <i>F. microcarpa</i> (<i>Josephiella microcarpae</i>) was also causing the galling on stems of the same plant. However, closer examination of the stem-galling wasps showed that while both the leaf-galler and the stem-galler are morphologically similar in many ways, this in fact may be a different species. Both leaf and stem-gallers can be found on the same plant. Jean-Yves Rasplus, co-author of the leaf-galling <i>J. microcarpae</i>, agreed that this could be an undescribed species and is currently working on its species description.</p> <p> Subsequent to the initial discovery of this stem-galler on Oahu in 2012, infested <i>F. microcarpa</i> were quickly noted on Hawaii and Maui. In May, 2016, galled <i>F. microcarpa</i> stems with exit holes were collected from Molokai and in July, 2017, from Kauai. However, material from these islands were too old and no adults could be recovered. Therefore, we do not list the collection data below, and in the list of new species we noted a question mark next to these islands until the adults are confirmed. <i>Josephiella</i> n. sp. A, along with <i>Josephiella microcarpae</i>, lobate lac scale (<i>Paratarchardina pseudolobata</i>), and other ficus-feeding species has contributed to the weakening of large banyan trees on Oahu.</p> <p> <b>Collection records: OAHU</b>, Manoa, 13.VII.2012, ex. <i>Ficus microcarpa</i> stems, coll. D. Hulbert, det. J.-Y. Rasplus, 6.X.2012.</p> <p> <b>HAWAII</b>, Hilo, 30.VII.2012, ex. <i>F. microcarpa</i> stems, coll. C. Hirayama, L. Larish & S. Chun, det. B. Kumashiro, VIII.2012.</p> <p> <b>MAUI</b>, Wailuku, 6.VIII.2012, ex. <i>F. microcarpa</i> stems, coll. M. Fukada, VIII.2012. Vouchers at HDOA.</p>Published as part of <i>Matsunaga, Janis N., Howarth, Francis G. & Kumashiro, Bernarr R., 2019, New State Records and Additions to the Alien Terrestrial Arthropod Fauna in the Hawaiian Islands, pp. 1-71 in Proceedings of the Hawaiian Entomological Society 51 (1)</i> on pages 11-12, DOI: <a href="http://zenodo.org/record/10832895">10.5281/zenodo.10832895</a>
Letter from Carl Hayden to P. J Moran
No full textLetter from Carl T. Hayden to P. J. Moran concerning the alignment of the road to Bright Angel Trail
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Implementation of an interior point source in the ultra weak variational formulation through source extraction
No full textThe Ultra Weak Variational Formulation (UWVF) is a powerful numerical method for the approximation of acoustic, elastic and electromagnetic waves in the time-harmonic regime. The use of Trefftz-type basis functions incorporates the known wave-like behaviour of the solution in the discrete space, allowing large reductions in the required number of degrees of freedom for a given accuracy, when compared to standard finite element methods. However, the UWVF is not well disposed to the accurate approximation of singular sources in the interior of the computational domain. We propose an adjustment to the UWVF for seismic imaging applications, which we call the Source Extraction UWVF. Differing fields are solved for in subdomains around the source, and matched on the inter-domain boundaries. Numerical results are presented for a domain of constant wavenumber and for a domain of varying sound speed in a model used for seismic imaging
Letter from P. J. Moran to Carl Hayden
No full textLetter from P. J. Moran to Carl T. Hayden inquiring when construction will begin on the approach road to Bright Angel Trail
Letter from P. J. Moran to Carl Hayden
No full textLetter from P. J. Moran to Carl T. Hayden inquiring when construction will begin on the approach road to Bright Angel Trai
Telegrams Between Carl Hayden to P. J. Moran, Democratic County Central Committee
No full textTelegram from Carl Hayden to P. J. Moran regarding the resignation of W. W. Crosby and his replacement J. R. Eakin
A 2 h periodic variation in the low-mass X-ray binary Ser X-1
No full textSpectroscopy of the low-mass X-ray binary Ser X-1 using the Gran Telescopio Canarias have revealed a ?2 h periodic variability that is present in the three strongest emission lines. We tentatively interpret this variability as due to orbital motion, making it the first indication of the orbital period of Ser X-1. Together with the fact that the emission lines are remarkably narrow, but still resolved, we show that a main-sequence K dwarf together with a canonical 1.4 M? neutron star gives a good description of the system. In this scenario, the most likely place for the emission lines to arise is the accretion disc, instead of a localized region in the binary (such as the irradiated surface or the stream-impact point), and their narrowness is due instead to the low inclination (?10°) of Ser X-1
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