638 research outputs found
Observation of 2nd band vortex solitons in 2D photonic lattices
We demonstrate second-band bright vortex-array solitons in photonic lattices.
This constitutes the first experimental observation of higher-band solitons in
any 2D periodic system. These solitons possess complex intensity and phase
structures, yet they can be excited by a simple highly-localized vortex-ring
beam. Finally, we show that the linear diffraction of such beams exhibits
preferential transport along the lattice axes
Neutralizing Antibody Responses to Human Immunodeficiency Virus Type 1 in Primary Infection and Long-Term-Nonprogressive Infection
The role of neutralizing antibodies in human immunodeficiency virus type 1 (HIV-1) infection is poorly understood and was assessed by evaluating responses at different stages of infection. Undiluted sera from long-term nonprogressors (LTNP) had broad neutralizing antibodies against heterologous primary isolates and were more likely to neutralize the contemporaneous autologous isolate than were sera from short-term nonprogressors and progressors. In primary infection, envelopespecific IgG was detected before the initial decline in plasma viremia, but neutralizing antibodies developed more slowly. Here, neutralizing antibodies against strains SF-2 and MN were sometimes the first to be detected, but titers were low for at least 17 weeks from onset of symptoms. Neutralizing antibodies against the early autologous isolate were detected for 4 patients by 5-40 weeks but were undetectable in 2 additional patients for 27-45 weeks. The results indicate that neutralizing antibody responses are slow to develop during primary infection and are uniquely broad in LTN
Graphene transistors are insensitive to pH changes in solution
We observe very small gate-voltage shifts in the transfer characteristic of
as-prepared graphene field-effect transistors (GFETs) when the pH of the buffer
is changed. This observation is in strong contrast to Si-based ion-sensitive
FETs. The low gate-shift of a GFET can be further reduced if the graphene
surface is covered with a hydrophobic fluorobenzene layer. If a thin Al-oxide
layer is applied instead, the opposite happens. This suggests that clean
graphene does not sense the chemical potential of protons. A GFET can therefore
be used as a reference electrode in an aqueous electrolyte. Our finding sheds
light on the large variety of pH-induced gate shifts that have been published
for GFETs in the recent literature
Multi-frequency polarization properties of ten quasars on deca-parsec scales at z > 3
Global VLBI (EVN+VLBA) polarization observations at 5 and 8.4 GHz of ten high
redshift (z > 3) quasars are presented. The core and jet brightness
temperatures are found through modelling the self-calibrated uv-data with
Gaussian components, which provide reliable estimates of the flux density and
size of individual components. The observed high core brightness temperatures
(median K) are consistent with Doppler
boosted emission from a relativistic jet orientated close to the line-of-sight.
This can also explain the dramatic jet bends observed for some of our sources
since small intrinsic bends can be significantly amplified due to projection
effects in a highly beamed relativistic jet. We also model-fit the polarized
emission and, by taking the minimum angle separation between the model-fitted
polarization angles at 5 and 8.4 GHz, we calculate the minimum inferred Faraday
rotation measure (RM) for each component. We also calculate the
minimum intrinsic RM in the rest frame of the AGN (RM =
RM), first subtracting the integrated (presumed foreground)
RM in those cases where we felt we could do this reliably. The resulting mean
core RM is 5580 rad m, with a standard
deviation of 3390 rad m, for four high-z quasars for which we believe we
could reliably remove the foreground RM. We find relatively steep core and jet
spectral index values, with a median core spectral index of -0.3 and a median
jet spectral index of -1.0. Comparing our results with RM observations of more
nearby Active Galactic Nuclei at similar emitted frequencies does not provide
any significant evidence for dependence of the quasar nuclear environment with
redshift.Comment: Published in MNRAS. 18 pages, 7 figures, 5 table
Clinical Best Practice Advice for Hepatology and Liver Transplant Providers During the COVID‐19 Pandemic: AASLD Expert Panel Consensus Statement
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/156235/2/hep31281.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/156235/1/hep31281_am.pd
The emergence of synaesthesia in a Neuronal Network Model via changes in perceptual sensitivity and plasticity
Synaesthesia is an unusual perceptual experience in which an inducer stimulus triggers a percept in a different domain in addition to its own. To explore the conditions under which synaesthesia evolves, we studied a neuronal network model that represents two recurrently connected neural systems. The interactions in the network evolve according to learning rules that optimize sensory sensitivity. We demonstrate several scenarios, such as sensory deprivation or heightened plasticity, under which synaesthesia can evolve even though the inputs to the two systems are statistically independent and the initial cross-talk interactions are zero. Sensory deprivation is the known causal mechanism for acquired synaesthesia and increased plasticity is implicated in developmental synaesthesia. The model unifies different causes of synaesthesia within a single theoretical framework and repositions synaesthesia not as some quirk of aberrant connectivity, but rather as a functional brain state that can emerge as a consequence of optimising sensory information processing
Measurement of the cross-section and charge asymmetry of bosons produced in proton-proton collisions at TeV with the ATLAS detector
This paper presents measurements of the and cross-sections and the associated charge asymmetry as a
function of the absolute pseudorapidity of the decay muon. The data were
collected in proton--proton collisions at a centre-of-mass energy of 8 TeV with
the ATLAS experiment at the LHC and correspond to a total integrated luminosity
of 20.2~\mbox{fb^{-1}}. The precision of the cross-section measurements
varies between 0.8% to 1.5% as a function of the pseudorapidity, excluding the
1.9% uncertainty on the integrated luminosity. The charge asymmetry is measured
with an uncertainty between 0.002 and 0.003. The results are compared with
predictions based on next-to-next-to-leading-order calculations with various
parton distribution functions and have the sensitivity to discriminate between
them.Comment: 38 pages in total, author list starting page 22, 5 figures, 4 tables,
submitted to EPJC. All figures including auxiliary figures are available at
https://atlas.web.cern.ch/Atlas/GROUPS/PHYSICS/PAPERS/STDM-2017-13
The Interstellar Environment of our Galaxy
We review the current knowledge and understanding of the interstellar medium
of our galaxy. We first present each of the three basic constituents - ordinary
matter, cosmic rays, and magnetic fields - of the interstellar medium, laying
emphasis on their physical and chemical properties inferred from a broad range
of observations. We then position the different interstellar constituents, both
with respect to each other and with respect to stars, within the general
galactic ecosystem.Comment: 39 pages, 12 figures (including 3 figures in 2 parts
- …