133 research outputs found
High-Resolution Near-Field Raman Microscopy of Single-Walled Carbon Nanotubes
We present near-field Raman spectroscopy and imaging of single isolated single-walled carbon nanotubes with a spatial resolution of ≈25 nm. The near-field origin of the image contrast is confirmed by the measured dependence of the Raman scattering signal on tip-sample distance and the unique polarization properties. The method is used to study local variations in the Raman spectrum along a single single-walled carbon nanotube
Talking Past Each Other - A Discursive Approach to the Formation of Societal-Level Information Pathologies in the Context of the Electronic Health Card in Germany
An explorative case study is used to investigate the formation of information pathologies on the societal level. The paper conceptualizes these particular information pathologies as ‘interaction-related Information pathologies’ (Picot et al., Information, organization and management. Springer, Berlin, 2008) and proposes that the production of information by multiple stakeholders leads to ‘distortions’ (Cukier et al., Inf Syst J 19(2):175–196, 2009) on the societal level. This broad proposition is then explored by means of a qualitative case study of the media coverage surrounding the implementation of the ‘Electronic Health Card’ in Germany. Based on that study, the initial proposition is further specified by conceptualizing how a process of path constitution ‘distorts’ a debate from being about legitimacy of an ICT innovation to being about illegitimacy of stakeholders
Gravitational Waves from Disks Around Spinning Black Holes: Simulations in Full General Relativity
We present fully general-relativistic numerical evolutions of
self-gravitating tori around spinning black holes with dimensionless spin parallel or anti-parallel to the disk angular momentum. The initial
disks are unstable to the hydrodynamic Papaloizou-Pringle Instability which
causes them to grow persistent orbiting matter clumps. The effect of black hole
spin on the growth and saturation of the instability is assessed. We find that
the instability behaves similarly to prior simulations with non-spinning black
holes, with a shift in frequency due to spin-induced changes in disk orbital
period. Copious gravitational waves are generated by these systems, and we
analyze their detectability by current and future gravitational wave
observatories for large range of masses. We find that systems of -
relevant for black hole-neutron star mergers - are detectable by Cosmic
Explorer out to Mpc, while DECIGO (LISA) will be able to detect
systems of () - relevant for disks forming in
collapsing supermassive stars - out to cosmological redshift of
(). Computing the accretion rate of these systems we find that these
systems may also be promising sources of coincident electromagnetic signals.Comment: 15 pages, 12 figure
Effect of magnetic fields on the dynamics and gravitational wave emission of PPI-saturated self-gravitating accretion disks: simulations in full GR
We explore the effect magnetic fields have on self-gravitating accretion
disks around spinning black holes via numerical evolutions in full dynamical
magnetohydrodynamic spacetimes. The configurations we study are unstable to the
Papaloizou-Pringle Instability (PPI). PPI-saturated accretion tori have been
shown to produce gravitational waves, detectable to cosmological distances by
third-generation gravitational wave (GW) observatories. While the PPI operates
strongly for purely hydrodynamic disks, the situation can be different for
disks hosting initially small magnetic fields. Evolutions of disks without
self-gravity in fixed BH spacetimes have shown that small seed fields can
initiate the rapid growth of the magneto-rotational instability (MRI), which
then strongly suppresses the PPI. Since realistic astrophysical disks are
expected to be magnetized, PPI-generated GW signals may be suppressed as well.
However, it is unclear what happens when the disk self-gravity is restored.
Here, we study the impact of magnetic fields on the PPI-saturated state of a
self-gravitating accretion disk around a spinning BH () aligned
with the disk angular momentum, as well as one around a non-spinning BH. We
find the MRI is effective at reducing the amplitude of PPI modes and their
associated GWs, but the systems still generate GWs. Estimating the
detectability of these systems accross a wide range of masses, we show that
magnetic fields reduce the maximum detection distance by Cosmic Explorer from
300Mpc (in the pure hydrodynamic case) to 45Mpc for a system, by
LISA from 11500Mpc to 2700Mpc for a system, and by
DECIGO from down to for a system
1-(10,11-Dihydrodibenz[b,f]azepin-5-yl)ethanone
The asymmetric unit of the title compound, Csb 16Hsb 15NO, comprises two independent mol-ecules (it A and it B), both adopting a half-boat conformation, or butterfly shape. The intramolecular dihedral angles between the benzene rings in it A and it B are 64.40(4) and 65.24(5)circ, respectively
Physics of eccentric binary black hole mergers: A numerical relativity perspective
Gravitational wave observations of eccentric binary black hole mergers will
provide unequivocal evidence for the formation of these systems through
dynamical assembly in dense stellar environments. The study of these
astrophysically motivated sources is timely in view of electromagnetic
observations, consistent with the existence of stellar mass black holes in the
globular cluster M22 and in the Galactic center, and the proven detection
capabilities of ground-based gravitational wave detectors. In order to get
insights into the physics of these objects in the dynamical, strong-field
gravity regime, we present a catalog of 89 numerical relativity waveforms that
describe binary systems of non-spinning black holes with mass-ratios , and initial eccentricities as high as fifteen cycles
before merger. We use this catalog to quantify the loss of energy and angular
momentum through gravitational radiation, and the astrophysical properties of
the black hole remnant, including its final mass and spin, and recoil velocity.
We discuss the implications of these results for gravitational wave source
modeling, and the design of algorithms to search for and identify eccentric
binary black hole mergers in realistic detection scenarios.Comment: 11 pages, 5 figures, 2 appendices. A visualization of this numerical
relativity waveform catalog is available at
https://gravity.ncsa.illinois.edu/products/outreach/; v2: 13 pages, 5
figures, calculations for angular momentum emission and recoil velocities are
now included, references added. Accepted to Phys. Rev.
Basal and LPS-stimulated inflammatory markers and the course of individual symptoms of depression
Multiple studies show an association between inflammatory markers and major depressive disorder (MDD). People with chronic low-grade inflammation may be at an increased risk of MDD, often in the form of sickness behaviors. We hypothesized that inflammation is predictive of the severity and the course of a subset of MDD symptoms, especially symptoms that overlap with sickness behavior, such as anhedonia, anorexia, low concentration, low energy, loss of libido, psychomotor slowness, irritability, and malaise. We tested the association between basal and lipopolysaccharide (LPS)-induced inflammatory markers with individual MDD symptoms (measured using the Inventory of Depressive Symptomatology Self-Report) over a period of up to 9 years using multivariate-adjusted mixed models in 1147–2872 Netherlands Study of Depression and Anxiety (NESDA) participants. At baseline, participants were on average 42.2 years old, 66.5% were women and 53.9% had a current mood or anxiety disorder. We found that basal and LPS-stimulated inflammatory markers were more strongly associated with sickness behavior symptoms at up to 9-year follow-up compared with non-sickness behavior symptoms of depression. However, we also found significant associations with some symptoms that are not typical of sickness behavior (e.g., sympathetic arousal among others). Inflammation was not related to depression as a unified syndrome but rather to the presence and the course of specific MDD symptoms, of which the majority were related to sickness behavior. Anti-inflammatory strategies should be tested in the subgroup of MDD patients who report depressive symptoms related to sickness behavior
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