1,364 research outputs found
A variational principle for cyclic polygons with prescribed edge lengths
We provide a new proof of the elementary geometric theorem on the existence
and uniqueness of cyclic polygons with prescribed side lengths. The proof is
based on a variational principle involving the central angles of the polygon as
variables. The uniqueness follows from the concavity of the target function.
The existence proof relies on a fundamental inequality of information theory.
We also provide proofs for the corresponding theorems of spherical and
hyperbolic geometry (and, as a byproduct, in spacetime). The spherical
theorem is reduced to the euclidean one. The proof of the hyperbolic theorem
treats three cases separately: Only the case of polygons inscribed in compact
circles can be reduced to the euclidean theorem. For the other two cases,
polygons inscribed in horocycles and hypercycles, we provide separate
arguments. The hypercycle case also proves the theorem for "cyclic" polygons in
spacetime.Comment: 18 pages, 6 figures. v2: typos corrected, final versio
Haplotype and isoform specific expression estimation using multi-mapping RNA-seq reads
We present a novel pipeline and methodology for simultaneously estimating isoform expression and allelic imbalance in diploid organisms using RNA-seq data. We achieve this by modeling the expression of haplotype-specific isoforms. If unknown, the two parental isoform sequences can be individually reconstructed. A new statistical method, MMSEQ, deconvolves the mapping of reads to multiple transcripts (isoforms or haplotype-specific isoforms). Our software can take into account non-uniform read generation and works with paired-end reads
Blow-up profile of rotating 2D focusing Bose gases
We consider the Gross-Pitaevskii equation describing an attractive Bose gas
trapped to a quasi 2D layer by means of a purely harmonic potential, and which
rotates at a fixed speed of rotation . First we study the behavior of
the ground state when the coupling constant approaches , the critical
strength of the cubic nonlinearity for the focusing nonlinear Schr{\"o}dinger
equation. We prove that blow-up always happens at the center of the trap, with
the blow-up profile given by the Gagliardo-Nirenberg solution. In particular,
the blow-up scenario is independent of , to leading order. This
generalizes results obtained by Guo and Seiringer (Lett. Math. Phys., 2014,
vol. 104, p. 141--156) in the non-rotating case. In a second part we consider
the many-particle Hamiltonian for bosons, interacting with a potential
rescaled in the mean-field manner w\int\_{\mathbb{R}^2} w(x) dx = 1\beta < 1/2a\_N \to a\_*N \to \infty$
Special Values of Generalized Polylogarithms
We study values of generalized polylogarithms at various points and
relationships among them. Polylogarithms of small weight at the points 1/2 and
-1 are completely investigated. We formulate a conjecture about the structure
of the linear space generated by values of generalized polylogarithms.Comment: 32 page
Mechanism of resonant electron emission from the deprotonated GFP chromophore and its biomimetics
The Green Fluorescent Protein (GFP), which is widely used in bioimaging, is known to undergo light-induced redox transformations. Electron transfer is thought to occur resonantly through excited states of its chromophore; however, a detailed understanding of the electron gateway states of the chromophore is still missing. Here, we use photoelectron spectroscopy and high-level quantum chemistry calculations to show that following UV excitation, the ultrafast electron dynamics in the chromophore anion proceeds via an excited shape resonance strongly coupled to the open continuum. The impact of this state is found across the entire 355–315 nm excitation range, from above the first bound–bound transition to below the opening of higher-lying continua. By disentangling the electron dynamics in the photodetachment channels, we provide an important reference for the adiabatic position of the electron gateway state, which is located at 348 nm, and discover the source of the curiously large widths of the photoelectron spectra that have been reported in the literature. By introducing chemical modifications to the GFP chromophore, we show that the detachment threshold and the position of the gateway state, and hence the underlying excited-state dynamics, can be changed systematically. This enables a fine tuning of the intrinsic electron emission properties of the GFP chromophore and has significant implications for its function, suggesting that the biomimetic GFP chromophores are more stable to photooxidation
SUPPORT Tools for Evidence-informed Policymaking in health 6: Using research evidence to address how an option will be implemented
This article is part of a series written for people responsible for making decisions about health policies and programmes and for those who support these decision makers
SUPPORT Tools for evidence-informed health Policymaking (STP) 7: Finding systematic reviews
This article is part of a series written for people responsible for making decisions about health policies and programmes and for those who support these decision makers
EXO 0748-676 Rules out Soft Equations of State for Neutron Star Matter
The interiors of neutron stars contain matter at very high densities, in a
state that differs greatly from those found in the early universe or achieved
at terrestrial experiments. Matter in these conditions can only be probed
through astrophysical observations that measure the mass and radius of neutron
stars with sufficient precision. Here I report for the first time a unique
determination of the mass and radius of the neutron star EXO 0748-676, which
appears to rule out all the soft equations of state of neutron star matter. If
this object is typical, then condensates and unconfined quarks do not exist in
the centers of neutron stars.Comment: To appear in Nature, press embargo until publicatio
Dual mobility versus conventional total hip arthroplasty in femoral neck fractures (DISTINCT): protocol for a registry-nested, open-label, cluster-randomised crossover trial
Introduction Hip fractures treated with total hip arthroplasty (THA) are at high risk of prosthesis instability, and dislocation is the most common indication for revision surgery. This study aims to determine whether dual mobility THA implants reduce the risk of dislocation compared with conventional THA in patients with hip fracture suitable to be treated with THA. Methods and analysis This is a cluster-randomised, crossover, open-label trial nested within the Australian Orthopaedic Association National Joint Replacement Registry (AOANJRR). The clusters will comprise hospitals that perform at least 12 THAs for hip fracture per annum. All adults age ≥50 years who meet the Australian and New Zealand Hip Fracture Registry guidelines for THA will be included. The intervention will be dual mobility THA and the comparator will be conventional THA. Each hospital will be allocated to two consecutive periods, one of dual mobility THA and the other of conventional THA in random order, aiming for an average of 16 patients eligible for the primary analysis per group (32 total per site), allowing different recruitment totals between sites. Data will be collected through the AOANJRR and linked with patient-level discharge data acquired through government agencies. The primary outcome is dislocation within 1 year. Secondary outcomes include revision surgery for dislocation and all-cause, complications and mortality at 1, 2 and 5 years. If dual mobility THA is found to be superior, a cost-effectiveness analysis will be conducted. The study will aim to recruit 1536 patients from at least 48 hospitals over 3 years. Ethics and dissemination Ethics approval has been granted (Sydney Local Health District - Royal Prince Alfred Hospital Zone (approval X20-0162 and 2020/ETH00680) and site-specific approvals). Participant recruitment is via an opt-out consent process as both treatments are considered accepted, standard practice. The trial is endorsed by the Australia and New Zealand Musculoskeletal Clinical Trials Network. Trial registration number ACTRN12621000069853
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