119 research outputs found
Genomic evolution and polymorphism: Segmental duplications and haplotypes at 108 regions on 21 chromosomes
We describe here extensive, previously unknown, genomic polymorphism in 120 regions, covering 19 autosomes and both sex chromosomes. Each contains duplication within multigene clusters. Of these, 108 are extremely polymorphic with multiple haplotypes.We used the genomic matching technique (GMT), previously used to characterise the major histocompatibility complex (MHC) and regulators of complement activation (RCA).This genome-wide extension of this technique enables the examination of many underlying cis, trans and epistatic interactions responsible for phenotypic differences especially in relation to individuality, evolution and disease susceptibility.The extent of the diversity could not have been predicted and suggests a new model of primate evolution based on conservation of polymorphism rather than de novo mutation
Characteristic Polynomials of Sample Covariance Matrices: The Non-Square Case
We consider the sample covariance matrices of large data matrices which have
i.i.d. complex matrix entries and which are non-square in the sense that the
difference between the number of rows and the number of columns tends to
infinity. We show that the second-order correlation function of the
characteristic polynomial of the sample covariance matrix is asymptotically
given by the sine kernel in the bulk of the spectrum and by the Airy kernel at
the edge of the spectrum. Similar results are given for real sample covariance
matrices
Linear Statistics of Point Processes via Orthogonal Polynomials
For arbitrary , we use the orthogonal polynomials techniques
developed by R. Killip and I. Nenciu to study certain linear statistics
associated with the circular and Jacobi ensembles. We identify the
distribution of these statistics then prove a joint central limit theorem. In
the circular case, similar statements have been proved using different methods
by a number of authors. In the Jacobi case these results are new.Comment: Added references, corrected typos. To appear, J. Stat. Phy
Derivative moments for characteristic polynomials from the CUE
We calculate joint moments of the characteristic polynomial of a random
unitary matrix from the circular unitary ensemble and its derivative in the
case that the power in the moments is an odd positive integer. The calculations
are carried out for finite matrix size and in the limit as the size of the
matrices goes to infinity. The latter asymptotic calculation allows us to prove
a long-standing conjecture from random matrix theory.Comment: 31 pages, 3 figure
Asymptotics for products of characteristic polynomials in classical -Ensembles
We study the local properties of eigenvalues for the Hermite (Gaussian),
Laguerre (Chiral) and Jacobi -ensembles of random matrices.
More specifically, we calculate scaling limits of the expectation value of
products of characteristic polynomials as . In the bulk of the
spectrum of each -ensemble, the same scaling limit is found to be
whose exact expansion in terms of Jack polynomials is well
known. The scaling limit at the soft edge of the spectrum for the Hermite and
Laguerre -ensembles is shown to be a multivariate Airy function, which
is defined as a generalized Kontsevich integral. As corollaries, when
is even, scaling limits of the -point correlation functions for the three
ensembles are obtained. The asymptotics of the multivariate Airy function for
large and small arguments is also given. All the asymptotic results rely on a
generalization of Watson's lemma and the steepest descent method for integrals
of Selberg type.Comment: [v3] 35 pages; this is a revised and enlarged version of the article
with new references, simplified demonstations, and improved presentation. To
be published in Constructive Approximation 37 (2013
The delivery of personalised, precision medicines via synthetic proteins
Introduction:
The design of advanced drug delivery systems based on synthetic and su-pramolecular chemistry has been very successful. Liposomal doxorubicin (Caelyx®), and liposomal daunorubicin (DaunoXome®), estradiol topical emulsion (EstrasorbTM) as well as soluble or erodible polymer systems such as pegaspargase (Oncaspar®) or goserelin acetate (Zoladex®) represent considerable achievements.
The Problem:
As deliverables have evolved from low molecular weight drugs to biologics (currently representing approximately 30% of the market), so too have the demands made of advanced drug delivery technology. In parallel, the field of membrane trafficking (and endocytosis) has also matured. The trafficking of specific receptors i.e. material to be recycled or destroyed, as well as the trafficking of protein toxins has been well characterized. This, in conjunction with an ability to engineer synthetic, recombinant proteins provides several possibilities.
The Solution:
The first is using recombinant proteins as drugs i.e. denileukin diftitox (Ontak®) or agalsidase beta (Fabrazyme®). The second is the opportunity to use protein toxin architecture to reach targets that are not normally accessible. This may be achieved by grafting regulatory domains from multiple species to form synthetic proteins, engineered to do multiple jobs. Examples include access to the nucleocytosolic compartment. Herein the use of synthetic proteins for drug delivery has been reviewed
Para-infectious brain injury in COVID-19 persists at follow-up despite attenuated cytokine and autoantibody responses
To understand neurological complications of COVID-19 better both acutely and for recovery, we measured markers of brain injury, inflammatory mediators, and autoantibodies in 203 hospitalised participants; 111 with acute sera (1–11 days post-admission) and 92 convalescent sera (56 with COVID-19-associated neurological diagnoses). Here we show that compared to 60 uninfected controls, tTau, GFAP, NfL, and UCH-L1 are increased with COVID-19 infection at acute timepoints and NfL and GFAP are significantly higher in participants with neurological complications. Inflammatory mediators (IL-6, IL-12p40, HGF, M-CSF, CCL2, and IL-1RA) are associated with both altered consciousness and markers of brain injury. Autoantibodies are more common in COVID-19 than controls and some (including against MYL7, UCH-L1, and GRIN3B) are more frequent with altered consciousness. Additionally, convalescent participants with neurological complications show elevated GFAP and NfL, unrelated to attenuated systemic inflammatory mediators and to autoantibody responses. Overall, neurological complications of COVID-19 are associated with evidence of neuroglial injury in both acute and late disease and these correlate with dysregulated innate and adaptive immune responses acutely
Broadband multi-wavelength properties of M87 during the 2017 Event Horizon Telescope campaign
In 2017, the Event Horizon Telescope (EHT) Collaboration succeeded in capturing the first direct image of the
center of the M87 galaxy. The asymmetric ring morphology and size are consistent with theoretical expectations
for a weakly accreting supermassive black hole of mass ∼6.5 × 109Me. The EHTC also partnered with several
international facilities in space and on the ground, to arrange an extensive, quasi-simultaneous multi-wavelength
campaign. This Letter presents the results and analysis of this campaign, as well as the multi-wavelength data as a
legacy data repository. We captured M87 in a historically low state, and the core flux dominates over HST-1 at
high energies, making it possible to combine core flux constraints with the more spatially precise very long
baseline interferometry data. We present the most complete simultaneous multi-wavelength spectrum of the active
nucleus to date, and discuss the complexity and caveats of combining data from different spatial scales into one
broadband spectrum. We apply two heuristic, isotropic leptonic single-zone models to provide insight into the
basic source properties, but conclude that a structured jet is necessary to explain M87’s spectrum. We can exclude
that the simultaneous γ-ray emission is produced via inverse Compton emission in the same region producing the
EHT mm-band emission, and further conclude that the γ-rays can only be produced in the inner jets (inward of
HST-1) if there are strongly particle-dominated regions. Direct synchrotron emission from accelerated protons and
secondaries cannot yet be excluded.http://iopscience.iop.org/2041-8205am2022Physic
First Sagittarius A* Event Horizon Telescope Results. IV. Variability, Morphology, and Black Hole Mass
In this paper we quantify the temporal variability and image morphology of the horizon-scale emission from Sgr A*, as observed by the EHT in 2017 April at a wavelength of 1.3 mm. We find that the Sgr A* data exhibit variability that exceeds what can be explained by the uncertainties in the data or by the effects of interstellar scattering. The magnitude of this variability can be a substantial fraction of the correlated flux density, reaching ∼100% on some baselines. Through an exploration of simple geometric source models, we demonstrate that ring-like morphologies provide better fits to the Sgr A* data than do other morphologies with comparable complexity. We develop two strategies for fitting static geometric ring models to the time-variable Sgr A* data; one strategy fits models to short segments of data over which the source is static and averages these independent fits, while the other fits models to the full data set using a parametric model for the structural variability power spectrum around the average source structure. Both geometric modeling and image-domain feature extraction techniques determine the ring diameter to be 51.8 ± 2.3 μas (68% credible intervals), with the ring thickness constrained to have an FWHM between ∼30% and 50% of the ring diameter. To bring the diameter measurements to a common physical scale, we calibrate them using synthetic data generated from GRMHD simulations. This calibration constrains the angular size of the gravitational radius to be 4.8−0.7+1.4 μas, which we combine with an independent distance measurement from maser parallaxes to determine the mass of Sgr A* to be 4.0−0.6+1.1×106 M ⊙
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