39 research outputs found

    Seshadri constants and Grassmann bundles over curves

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    Let XX be a smooth complex projective curve, and let EE be a vector bundle on XX which is not semistable. For a suitably chosen integer rr, let Gr(E)\text{Gr}(E) be the Grassmann bundle over XX that parametrizes the quotients of the fibers of EE of dimension rr. Assuming some numerical conditions on the Harder-Narasimhan filtration of EE, we study Seshadri constants of ample line bundles on Gr(E)\text{Gr}(E). In many cases, we give the precise value of Seshadri constant. Our results generalize various known results for rank(E)=2{\rm rank}(E)=2.Comment: Final version; Annales Inst. Fourier (to appear

    Studies in the formation of heterocyclic rings containing nitrogen. Part XXIII. Condensation of o-aminobenzamide with aldehydes and Schiff bases

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    N-arylidene orthanilamides undergo isomeric cyclisation in acetic acid to the corresponding 2-aryl-1, 2, 3, 4-tetrahydro-4-oxoquinazolines. The u.v. and n.m.r. spectra of some of the arylidene derivatives and their isomeric tetrahydroquinazolines have neeb studied. Condensation of o-aminobenzamide either with aromatic aldehydes in nitrobenzene or Schiff bases in acetic acid has yielded 2-aryl-4 (3H)-quinazolinones

    Lagrangian simulations of the transport of young air masses to the top of the Asian monsoon anticyclone and into the tropical pipe

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    We have performed backward trajectory calculations and simulations with the three-dimensional Chemical Lagrangian Model of the Stratosphere (CLaMS) for two succeeding monsoon seasons using artificial tracers of air mass origin. With these tracers we trace back the origin of young air masses (age&thinsp;&lt;6 months) at the top of the Asian monsoon anticyclone and of air masses within the tropical pipe (6 months&thinsp;&lt;&thinsp;age&thinsp;&lt;18 months) during summer 2008. The occurrence of young air masses (&lt;6 months) at the top of the Asian monsoon anticyclone up to ∼460&thinsp;K is in agreement with satellite measurements of chlorodifluoromethane (HCFC-22) by the Michelson Interferometer for Passive Atmospheric Sounding (MIPAS) instrument. HCFC-22 can be considered as a regional tracer for continental eastern Asia and the Middle East as it is mainly emitted in this region. Our findings show that the transport of air masses from boundary layer sources in the region of the Asian monsoon into the tropical pipe occurs in three distinct steps. First, very fast uplift in “a convective range” transports air masses up to 360&thinsp;K potential temperature within a few days. Second, air masses are uplifted from about 360&thinsp;K up to 460&thinsp;K within “an upward spiralling range” within a few months. The large-scale upward spiral extends from northern Africa to the western Pacific. The air masses are transported upwards by diabatic heating with a rate of up to 1–1.5&thinsp;K per day, implying strong vertical transport above the Asian monsoon anticyclone. Third, transport of air masses occurs within the tropical pipe up to 550&thinsp;K associated with the large-scale Brewer–Dobson circulation within ∼1 year. In the upward spiralling range, air masses are uplifted by diabatic heating across the (lapse rate) tropopause, which does not act as a transport barrier, in contrast to the extratropical tropopause. Further, in the upward spiralling range air masses from inside the Asian monsoon anticyclone are mixed with air masses convectively uplifted outside the core of the Asian monsoon anticyclone in the tropical adjacent regions. Moreover, the vertical transport of air masses from the Asian monsoon anticyclone into the tropical pipe is weak in terms of transported air masses compared to the transport from the monsoon anticyclone into the northern extratropical lower stratosphere. Air masses from the Asian monsoon anticyclone (India/China) contribute a minor fraction to the composition of air within the tropical pipe at 550&thinsp;K (6&thinsp;%), and the major fractions are from Southeast Asia (16&thinsp;%) and the tropical Pacific (15&thinsp;%).</p

    Human protein reference database—2006 update

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    Human Protein Reference Database (HPRD) () was developed to serve as a comprehensive collection of protein features, post-translational modifications (PTMs) and protein–protein interactions. Since the original report, this database has increased to >20 000 proteins entries and has become the largest database for literature-derived protein–protein interactions (>30 000) and PTMs (>8000) for human proteins. We have also introduced several new features in HPRD including: (i) protein isoforms, (ii) enhanced search options, (iii) linking of pathway annotations and (iv) integration of a novel browser, GenProt Viewer (), developed by us that allows integration of genomic and proteomic information. With the continued support and active participation by the biomedical community, we expect HPRD to become a unique source of curated information for the human proteome and spur biomedical discoveries based on integration of genomic, transcriptomic and proteomic data

    Angle-closure glaucoma secondary to inflammatory capsular block syndrome following routine cataract surgery

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    A 78-year-old man had uneventful cataract surgery with implantation of a 1-piece plate–haptic intraocular lens in the capsular bag. Seven weeks later, he presented as an emergency with intense fibrinous uveitis and increased intraocular pressure (IOP). Examination revealed an inflammatory capsular block syndrome (CBS) causing fibrinous anterior uveitis and secondary angle-closure glaucoma. The glaucoma resolved and the patient’s vision improved following neodymium:YAG laser posterior capsulotomy. Inflammatory CBS should be considered in pseudophakic patients presenting with fibrinous anterior uveitis, increased IOP, and secondary angle closure
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