77 research outputs found
Section Extension from Hyperbolic Geometry of Punctured Disk and Holomorphic Family of Flat Bundles
The construction of sections of bundles with prescribed jet values plays a
fundamental role in problems of algebraic and complex geometry. When the jet
values are prescribed on a positive dimensional subvariety, it is handled by
theorems of Ohsawa-Takegoshi type which give extension of line bundle valued
square-integrable top-degree holomorphic forms from the fiber at the origin of
a family of complex manifolds over the open unit 1-disk when the curvature of
the metric of line bundle is semipositive. We prove here an extension result
when the curvature of the line bundle is only semipositive on each fiber with
negativity on the total space assumed bounded from below and the connection of
the metric locally bounded, if a square-integrable extension is known to be
possible over a double point at the origin. It is a Hensel-lemma-type result
analogous to Artin's application of the generalized implicit function theorem
to the theory of obstruction in deformation theory. The motivation is the need
in the abundance conjecture to construct pluricanonical sections from flatly
twisted pluricanonical sections. We also give here a new approach to the
original theorem of Ohsawa-Takegoshi by using the hyperbolic geometry of the
punctured open unit 1-disk to reduce the original theorem of Ohsawa-Takegoshi
to a simple application of the standard method of constructing holomorphic
functions by solving the d-bar equation with cut-off functions and additional
blowup weight functions
Quantum numbers of the state and orbital angular momentum in its decay
Angular correlations in decays, with , and , are used to measure
orbital angular momentum contributions and to determine the value of
the meson. The data correspond to an integrated luminosity of 3.0
fb of proton-proton collisions collected with the LHCb detector. This
determination, for the first time performed without assuming a value for the
orbital angular momentum, confirms the quantum numbers to be .
The is found to decay predominantly through S wave and an upper limit
of at C.L. is set on the fraction of D wave.Comment: 16 pages, 4 figure
Whole genome analysis of a schistosomiasis-transmitting freshwater snail
Biomphalaria snails are instrumental in transmission of the human blood fluke Schistosoma mansoni. With the World Health Organization's goal to eliminate schistosomiasis as a global health problem by 2025, there is now renewed emphasis on snail control. Here, we characterize the genome of Biomphalaria glabrata, a lophotrochozoan protostome, and provide timely and important information on snail biology. We describe aspects of phero-perception, stress responses, immune function and regulation of gene expression that support the persistence of B. glabrata in the field and may define this species as a suitable snail host for S. mansoni. We identify several potential targets for developing novel control measures aimed at reducing snail-mediated transmission of schistosomiasis
Measurement of Upsilon production in pp collisions at \sqrt{s} = 7 TeV
The production of Upsilon(1S), Upsilon(2S) and Upsilon(3S) mesons in
proton-proton collisions at the centre-of-mass energy of sqrt(s)=7 TeV is
studied with the LHCb detector. The analysis is based on a data sample of 25
pb-1 collected at the Large Hadron Collider. The Upsilon mesons are
reconstructed in the decay mode Upsilon -> mu+ mu- and the signal yields are
extracted from a fit to the mu+ mu- invariant mass distributions. The
differential production cross-sections times dimuon branching fractions are
measured as a function of the Upsilon transverse momentum pT and rapidity y,
over the range pT < 15 GeV/c and 2.0 < y < 4.5. The cross-sections times
branching fractions, integrated over these kinematic ranges, are measured to be
sigma(pp -> Upsilon(1S) X) x B(Upsilon(1S)->mu+ mu-) = 2.29 {\pm} 0.01 {\pm}
0.10 -0.37 +0.19 nb, sigma(pp -> Upsilon(2S) X) x B(Upsilon(2S)->mu+ mu-) =
0.562 {\pm} 0.007 {\pm} 0.023 -0.092 +0.048 nb, sigma(pp -> Upsilon(3S) X) x
B(Upsilon(3S)->mu+ mu-) = 0.283 {\pm} 0.005 {\pm} 0.012 -0.048 +0.025 nb, where
the first uncertainty is statistical, the second systematic and the third is
due to the unknown polarisation of the three Upsilon states.Comment: 22 pages, 7 figure
Evidence for CP violation in time-integrated D0 -> h-h+ decay rates
A search for time-integrated CP violation in D0 -> h-h+ (h=K, pi) decays is
presented using 0.62 fb^-1 of data collected by LHCb in 2011. The flavor of the
charm meson is determined by the charge of the slow pion in the D*+ -> D0 pi+
and D*- -> D0bar pi- decay chains. The difference in CP asymmetry between D0 ->
K-K+ and D0 -> pi-pi+, Delta ACP = ACP(K-K+) - ACP(pi-pi+), is measured to be
[-0.82 \pm 0.21(stat.) \pm 0.11(syst.)]%. This differs from the hypothesis of
CP conservation by 3.5 standard deviations.Comment: 8 pages, 3 figures, 2 tables; v2 minor updates after journal revie
Measurement of the branching fraction and angular amplitudes
A search for the decay with is performed with 0.37 fb of collisions at
= 7 TeV collected by the LHCb experiment, finding a \Bs \to J\psi
K^-\pi^+ peak of signal events. The mass spectrum of
the candidates in the peak is dominated by the contribution.
Subtracting the non-resonant component, the branching fraction of
\BsJpsiKst is , where the first
uncertainty is statistical and the second systematic. A fit to the angular
distribution of the decay products yields the \Kst polarization fractions and
Corrigendum: Whole genome analysis of a schistosomiasis-transmitting freshwater snail
This corrects the article DOI: 10.1038/ncomms15451
Evaluation of appendicitis risk prediction models in adults with suspected appendicitis
Background
Appendicitis is the most common general surgical emergency worldwide, but its diagnosis remains challenging. The aim of this study was to determine whether existing risk prediction models can reliably identify patients presenting to hospital in the UK with acute right iliac fossa (RIF) pain who are at low risk of appendicitis.
Methods
A systematic search was completed to identify all existing appendicitis risk prediction models. Models were validated using UK data from an international prospective cohort study that captured consecutive patients aged 16–45 years presenting to hospital with acute RIF in March to June 2017. The main outcome was best achievable model specificity (proportion of patients who did not have appendicitis correctly classified as low risk) whilst maintaining a failure rate below 5 per cent (proportion of patients identified as low risk who actually had appendicitis).
Results
Some 5345 patients across 154 UK hospitals were identified, of which two‐thirds (3613 of 5345, 67·6 per cent) were women. Women were more than twice as likely to undergo surgery with removal of a histologically normal appendix (272 of 964, 28·2 per cent) than men (120 of 993, 12·1 per cent) (relative risk 2·33, 95 per cent c.i. 1·92 to 2·84; P < 0·001). Of 15 validated risk prediction models, the Adult Appendicitis Score performed best (cut‐off score 8 or less, specificity 63·1 per cent, failure rate 3·7 per cent). The Appendicitis Inflammatory Response Score performed best for men (cut‐off score 2 or less, specificity 24·7 per cent, failure rate 2·4 per cent).
Conclusion
Women in the UK had a disproportionate risk of admission without surgical intervention and had high rates of normal appendicectomy. Risk prediction models to support shared decision‐making by identifying adults in the UK at low risk of appendicitis were identified
Number theory - Rational points in periodic analytic sets and the Manin-Mumford conjecture
We present a new proof of the Manin-Mumford conjecture about torsion points on algebraic subvarieties of abelian varieties. Our principle, which admits other applications, is to view torsion points as rational points on a complex torus and then compare (i) upper bounds for the number of rational points on a transcendental analytic variety (Bombieri-Pila-Wilkie) and (ii) lower bounds for the degree of a torsion point (Masser), after taking conjugates. In order to be able to deal with (i), we discuss (Thm. 2.1) the semialgebraic curves contained in an analytic variety supposed invariant under translations by a full lattice, which is a topic with some independent motivation
Rational points in periodic analytic sets and the Manin-Mumford conjecture. Atti Accad. Naz. Lincei Cl. Sci. Fis. Mat. Natur. Rend. Lincei (9) Mat. Appl. 19 (2008), no. 2, 149--162
The paper gives a completely new proof of the Manin-Mumford conjecture. The method may be applied to a bunch of other problems
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