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https://www.readbyqxmd.com/read/28915271/extending-topological-surgery-to-natural-processes-and-dynamical-systems
#1
Stathis Antoniou, Sofia Lambropoulou
Topological surgery is a mathematical technique used for creating new manifolds out of known ones. We observe that it occurs in natural phenomena where a sphere of dimension 0 or 1 is selected, forces are applied and the manifold in which they occur changes type. For example, 1-dimensional surgery happens during chromosomal crossover, DNA recombination and when cosmic magnetic lines reconnect, while 2-dimensional surgery happens in the formation of tornadoes, in the phenomenon of Falaco solitons, in drop coalescence and in the cell mitosis...
2017: PloS One
https://www.readbyqxmd.com/read/28894863/circular-torsion-induced-fan-blade-shaped-wrinkling-in-two-dimensional-nano-rings
#2
Hongwei Bao, Yuhong Huang, Zhi Yang, Yaping Miao, Yunjin Sun, Yu Bai, Kewei Xu, Fei Ma
Molecular dynamics (MD) simulations are conducted to study the deformation behavior and strain distribution in two-dimensional (2D) nano-rings of graphene, single-layer black phosphorus (SLBP) and single-layer MoS2 (SLMoS2) under circular torsion. Interestingly, fan-blade shaped wrinkling is generated, in which the maximum torsion angle (Δθ) and the potential energy change per atom (ΔPe) increase with increasing inner radius but decrease with increasing temperature. As the inner radius is increased, the wave number of wrinkling increases but the wave amplitude decreases...
September 12, 2017: Physical Chemistry Chemical Physics: PCCP
https://www.readbyqxmd.com/read/28890683/rapid-processing-of-a-global-feature-in-the-on-visual-pathways-of-behaving-monkeys
#3
Jun Huang, Yan Yang, Ke Zhou, Xudong Zhao, Quan Zhou, Hong Zhu, Yingshan Yang, Chunming Zhang, Yifeng Zhou, Wu Zhou
Visual objects are recognized by their features. Whereas, some features are based on simple components (i.e., local features, such as orientation of line segments), some features are based on the whole object (i.e., global features, such as an object having a hole in it). Over the past five decades, behavioral, physiological, anatomical, and computational studies have established a general model of vision, which starts from extracting local features in the lower visual pathways followed by a feature integration process that extracts global features in the higher visual pathways...
2017: Frontiers in Neuroscience
https://www.readbyqxmd.com/read/28836595/distinguishing-spin-aligned-and-isotropic-black-hole-populations-with-gravitational-waves
#4
Will M Farr, Simon Stevenson, M Coleman Miller, Ilya Mandel, Ben Farr, Alberto Vecchio
The direct detection of gravitational waves from merging binary black holes opens up a window into the environments in which binary black holes form. One signature of such environments is the angular distribution of the black hole spins. Binary systems that formed through dynamical interactions between already-compact objects are expected to have isotropic spin orientations (that is, the spins of the black holes are randomly oriented with respect to the orbit of the binary system), whereas those that formed from pairs of stars born together are more likely to have spins that are preferentially aligned with the orbit...
August 23, 2017: Nature
https://www.readbyqxmd.com/read/28836587/gravitational-waves-history-of-black-holes-revealed-by-their-spin
#5
Steinn Sigurðsson
No abstract text is available yet for this article.
August 23, 2017: Nature
https://www.readbyqxmd.com/read/28816245/ram-pressure-feeding-of-supermassive-black-holes
#6
Bianca M Poggianti, Yara L Jaffé, Alessia Moretti, Marco Gullieuszik, Mario Radovich, Stephanie Tonnesen, Jacopo Fritz, Daniela Bettoni, Benedetta Vulcani, Giovanni Fasano, Callum Bellhouse, George Hau, Alessandro Omizzolo
When a supermassive black hole at the centre of a galaxy accretes matter, it gives rise to a highly energetic phenomenon: an active galactic nucleus. Numerous physical processes have been proposed to account for the funnelling of gas towards the galactic centre to feed the black hole. There are also several physical processes that can remove gas from a galaxy, one of which is ram-pressure stripping by the hot gas that fills the space between galaxies in galaxy clusters. Here we report that six out of a sample of seven 'jellyfish' galaxies-galaxies with long 'tentacles' of material that extend for dozens of kiloparsecs beyond the galactic disks-host an active nucleus, and two of them also have galactic-scale ionization cones...
August 16, 2017: Nature
https://www.readbyqxmd.com/read/28777598/primordial-black-holes-from-supersymmetry-in-the-early-universe
#7
Eric Cotner, Alexander Kusenko
Supersymmetric extensions of the standard model generically predict that in the early Universe a scalar condensate can form and fragment into Q balls before decaying. If the Q balls dominate the energy density for some period of time, the relatively large fluctuations in their number density can lead to formation of primordial black holes (PBH). Other scalar fields, unrelated to supersymmetry, can play a similar role. For a general charged scalar field, this robust mechanism can generate black holes over the entire mass range allowed by observational constraints, with a sufficient abundance to account for all dark matter in some parameter ranges...
July 21, 2017: Physical Review Letters
https://www.readbyqxmd.com/read/28765711/characteristics-and-predictors-of-progression-in-an-egyptian-multiple-sclerosis-cohort-a-multicenter-registry-study
#8
Sherif M Hamdy, Maged Abdel-Naseer, Nevin M Shalaby, Alaa N Elmazny, Ahmed A Nemr, Amr Hassan, Mohamed I Hegazy, Husam S Mourad, Nirmeen A Kishk, Mona A Nada, Ahmed Abdelalim, Amr M Fouad, Hatem S Shehata
BACKGROUND: Multiple sclerosis (MS) is a complex autoimmune disease with a heterogeneous presentation and diverse disease course. Recent studies indicate a rising prevalence of MS in the Middle East. OBJECTIVE: To characterize the demographics and disease features of Egyptian patients attending four tertiary referral MS centers in Cairo. MATERIALS AND METHODS: This was a retrospective, observational study on 1,581 patients between 2001 and 2015...
2017: Neuropsychiatric Disease and Treatment
https://www.readbyqxmd.com/read/28748924/significant-and-variable-linear-polarization-during-the-prompt-optical-flash-of-grb-160625b
#9
E Troja, V M Lipunov, C G Mundell, N R Butler, A M Watson, S Kobayashi, S B Cenko, F E Marshall, R Ricci, A Fruchter, M H Wieringa, E S Gorbovskoy, V Kornilov, A Kutyrev, W H Lee, V Toy, N V Tyurina, N M Budnev, D A H Buckley, J González, O Gress, A Horesh, M I Panasyuk, J X Prochaska, E Ramirez-Ruiz, R Rebolo Lopez, M G Richer, C Román-Zúñiga, M Serra-Ricart, V Yurkov, N Gehrels
Newly formed black holes of stellar mass launch collimated outflows (jets) of ionized matter that approach the speed of light. These outflows power prompt, brief and intense flashes of γ-rays known as γ-ray bursts (GRBs), followed by longer-lived afterglow radiation that is detected across the electromagnetic spectrum. Measuring the polarization of the observed GRB radiation provides a direct probe of the magnetic fields in the collimated jets. Rapid-response polarimetric observations of newly discovered bursts have probed the initial afterglow phase, and show that, minutes after the prompt emission has ended, the degree of linear polarization can be as high as 30 per cent-consistent with the idea that a stable, globally ordered magnetic field permeates the jet at large distances from the central source...
July 26, 2017: Nature
https://www.readbyqxmd.com/read/28738581/the-g-bhq-synergistic-effect-improved-double-quenching-molecular-beacons-based-on-guanine-and-black-hole-quencher-for-sensitive-simultaneous-detection-of-two-dnas
#10
Dongshan Xiang, Fengquan Li, Chenyi Wu, Boan Shi, Kun Zhai
We designed two double quenching molecular beacons (MBs) with simple structure based on guanine (G base) and Black Hole Quencher (BHQ), and developed a new analytical method for sensitive simultaneous detection of two DNAs by synchronous fluorescence analysis. In this analytical method, carboxyl fluorescein (FAM) and tetramethyl-6-carboxyrhodamine (TAMRA) were respectively selected as fluorophore of two MBs, Black Hole Quencher 1 (BHQ-1) and Black Hole Quencher 2 (BHQ-2) were respectively selected as organic quencher, and three continuous nucleotides with G base were connected to organic quencher (BHQ-1 and BHQ-2)...
November 1, 2017: Talanta
https://www.readbyqxmd.com/read/28731751/inferences-about-supernova-physics-from-gravitational-wave-measurements-gw151226-spin-misalignment-as-an-indicator-of-strong-black-hole-natal-kicks
#11
Richard O'Shaughnessy, Davide Gerosa, Daniel Wysocki
The inferred parameters of the binary black hole GW151226 are consistent with nonzero spin for the most massive black hole, misaligned from the binary's orbital angular momentum. If the black holes formed through isolated binary evolution from an initially aligned binary star, this misalignment would then arise from a natal kick imparted to the first-born black hole at its birth during stellar collapse. We use simple kinematic arguments to constrain the characteristic magnitude of this kick, and find that a natal kick v_{k}≳50  km/s must be imparted to the black hole at birth to produce misalignments consistent with GW151226...
July 7, 2017: Physical Review Letters
https://www.readbyqxmd.com/read/28701501/blood-pressure-reduction-and-noncontrast-ct-markers-of-intracerebral-hemorrhage-expansion
#12
RANDOMIZED CONTROLLED TRIAL
Andrea Morotti, Gregoire Boulouis, Javier M Romero, H Bart Brouwers, Michael J Jessel, Anastasia Vashkevich, Kristin Schwab, Mohammad Rauf Afzal, Christy Cassarly, Steven M Greenberg, Reneé Hebert Martin, Adnan I Qureshi, Jonathan Rosand, Joshua N Goldstein
OBJECTIVE: To validate various noncontrast CT (NCCT) predictors of hematoma expansion in a large international cohort of ICH patients and investigate whether intensive blood pressure (BP) treatment reduces ICH growth and improves outcome in patients with these markers. METHODS: We analyzed patients enrolled in the Antihypertensive Treatment of Acute Cerebral Hemorrhage II (ATACH-II) randomized controlled trial. Participants were assigned to intensive (systolic BP <140 mm Hg) vs standard (systolic BP <180 mm Hg) treatment within 4...
August 8, 2017: Neurology
https://www.readbyqxmd.com/read/28696338/black-holes-in-loop-quantum-gravity
#13
Alejandro Perez
This is a review of the results on black hole physics in the framework of loop quantum gravity. The key feature underlying the results is the discreteness of geometric quantities at the Planck scale predicted by this approach to quantum gravity. Quantum discreteness follows directly from the canonical quantization prescription when applied to the action of general relativity that is suitable for the coupling of gravity with gauge fields and specially with fermions. Planckian discreteness and causal considerations provide the basic structure for the understanding of the thermal properties of black holes close to equilibrium...
July 11, 2017: Reports on Progress in Physics
https://www.readbyqxmd.com/read/28693764/black-hole
#14
Karen Greenbaum-Maya
No abstract text is available yet for this article.
July 2017: Chest
https://www.readbyqxmd.com/read/28690421/the-kerr-cft-correspondence-and-its-extensions
#15
REVIEW
Geoffrey Compère
We present a first-principles derivation of the main results of the Kerr/CFT correspondence and its extensions using only tools from gravity and quantum field theory. Firstly, we review properties of extremal black holes with in particular the construction of an asymptotic Virasoro symmetry in the near-horizon limit. The entropy of extremal spinning or charged black holes is shown to match with a chiral half of Cardy's formula. Secondly, we show how a thermal 2-dimensional conformal field theory (CFT) is relevant to reproduce the dynamics of near-superradiant probes around near-extremal black holes in the semi-classical limit...
2017: Living Reviews in Relativity
https://www.readbyqxmd.com/read/28685353/peginterferon-beta-1a-reduces-the-evolution-of-mri-lesions-to-black-holes-in-patients-with-rrms-a-post-hoc-analysis-from-the-advance-study
#16
Douglas L Arnold, Xiaojun You, Carmen Castrillo-Viguera
The presence of chronic black holes, i.e., chronic lesions that are hypointense on T1-weighted images and are indicative of more severe tissue injury, has been increasingly utilized as a surrogate marker of therapeutic outcome in multiple sclerosis. The ADVANCE study was a 2-year, double-blind, pivotal trial evaluating the safety and efficacy of subcutaneous peginterferon beta-1a 125 mcg in 1512 patients with relapsing-remitting multiple sclerosis (RRMS). This report describes the correlation of clinical outcomes with the evolution of acute lesions into chronic black holes in ADVANCE, and the efficacy of peginterferon beta-1a in reducing this evolution...
August 2017: Journal of Neurology
https://www.readbyqxmd.com/read/28667692/hybrid-tio2-ruthenium-nano-photosensitizer-synergistically-produces-reactive-oxygen-species-in-both-hypoxic-and-normoxic-conditions
#17
Rebecca C Gilson, Kvar C L Black, Daniel D Lane, Samuel Achilefu
Photodynamic therapy (PDT) is widely used to treat diverse diseases, but its dependence on oxygen to produce cytotoxic reactive oxygen species (ROS) diminishes the therapeutic effect in a hypoxic environment, such as solid tumors. Herein, we developed a ROS-producing hybrid nanoparticle-based photosensitizer capable of maintaining high levels of ROS under both normoxic and hypoxic conditions. Conjugation of a ruthenium complex (N3) to a TiO2 nanoparticle afforded TiO2 -N3. Upon exposure of TiO2 -N3 to light, the N3 injected electrons into TiO2 to produce three- and four-fold more hydroxyl radicals and hydrogen peroxide, respectively, than TiO2 at 160 mmHg...
August 28, 2017: Angewandte Chemie
https://www.readbyqxmd.com/read/28666086/periodic-arrays-of-phosphorene-nanopores-as-antidot-lattices-with-tunable-properties
#18
Andrew Cupo, Paul Masih Das, Chen-Chi Chien, Gopinath Danda, Neerav Kharche, Damien Tristant, Marija Drndić, Vincent Meunier
A tunable band gap in phosphorene extends its applicability in nanoelectronic and optoelectronic applications. Here, we propose to tune the band gap in phosphorene by patterning antidot lattices, which are periodic arrays of holes or nanopores etched in the material, and by exploiting quantum confinement in the corresponding nanoconstrictions. We fabricated antidot lattices with radii down to 13 nm in few-layer black phosphorus flakes protected by an oxide layer and observed suppression of the in-plane phonon modes relative to the unmodified material via Raman spectroscopy...
July 25, 2017: ACS Nano
https://www.readbyqxmd.com/read/28665632/searching-for-primordial-black-holes-in-the-radio-and-x-ray-sky
#19
Daniele Gaggero, Gianfranco Bertone, Francesca Calore, Riley M T Connors, Mark Lovell, Sera Markoff, Emma Storm
We model the accretion of gas onto a population of massive primordial black holes in the Milky Way and compare the predicted radio and x-ray emission with observational data. We show that, under conservative assumptions on the accretion process, the possibility that O(10)M_{⊙} primordial black holes can account for all of the dark matter in the Milky Way is excluded at 5σ by a comparison with a Very Large Array radio catalog at 1.4 GHz and at ≃40σ by a comparison with a Chandra x-ray catalog (0.5-8 keV)...
June 16, 2017: Physical Review Letters
https://www.readbyqxmd.com/read/28654244/monolithically-integrated-flexible-black-phosphorus-complementary-inverter-circuits
#20
Yuanda Liu, Kah-Wee Ang
Two-dimensional (2D) inverters are a fundamental building block for flexible logic circuits which have previously been realized by heterogeneously wiring transistors with two discrete channel materials. Here, we demonstrate a monolithically integrated complementary inverter made using a homogeneous black phosphorus (BP) nanosheet on flexible substrates. The digital logic inverter circuit is demonstrated via effective threshold voltage tuning within a single BP material, which offers both electron and hole dominated conducting channels with nearly symmetric pinch-off and current saturation...
July 25, 2017: ACS Nano
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