27,951 research outputs found
Analysis of short pulse laser altimetry data obtained over horizontal path
Recent pulsed measurements of atmospheric delay obtained by ranging to the more realistic targets including a simulated ocean target and an extended plate target are discussed. These measurements are used to estimate the expected timing accuracy of a correlation receiver system. The experimental work was conducted using a pulsed two color laser altimeter
Langevin Trajectories between Fixed Concentrations
We consider the trajectories of particles diffusing between two infinite
baths of fixed concentrations connected by a channel, e.g. a protein channel of
a biological membrane. The steady state influx and efflux of Langevin
trajectories at the boundaries of a finite volume containing the channel and
parts of the two baths is replicated by termination of outgoing trajectories
and injection according to a residual phase space density. We present a
simulation scheme that maintains averaged fixed concentrations without creating
spurious boundary layers, consistent with the assumed physics
A luminous blue kilonova and an off-axis jet from a compact binary merger at z=0.1341
The recent discovery of a faint gamma-ray burst (GRB) coincident with the
gravitational wave (GW) event GW 170817 revealed the existence of a population
of low-luminosity short duration gamma-ray transients produced by neutron star
mergers in the nearby Universe. These events could be routinely detected by
existing gamma-ray monitors, yet previous observations failed to identify them
without the aid of GW triggers. Here we show that GRB150101B was an analogue of
GRB170817A located at a cosmological distance. GRB 150101B was a faint short
duration GRB characterized by a bright optical counterpart and a long-lived
X-ray afterglow. These properties are unusual for standard short GRBs and are
instead consistent with an explosion viewed off-axis: the optical light is
produced by a luminous kilonova component, while the observed X-rays trace the
GRB afterglow viewed at an angle of ~13 degrees. Our findings suggest that
these properties could be common among future electromagnetic counterparts of
GW sources.Comment: 28 pages, 8 figures, 2 tables. Accepted for publicatio
Rugoscopy in human identification: a study in a sample of twins
Palatal rugae patterns can be useful for forensic identification purposes. However, some doubts persist in concerning the pattern singularity in twins. The purpose of this study was to assess palatal rugae pattern singularity in a sample of twins. To do this, the palatal rugae patterns of 19 pairs of monozygotic twins and 47 pairs of dizygotic twins were studied. Our results showed that in monozygotic twins, no statistical significant differences were found, either in the form or number of palatal rugae. However, in dizygotic twins, differences were found in the number or shape of all palatal rugae (except for the shape of the first two right ones), suggesting that the palatal rugae pattern can be useful for identification purposes of dizygotic, but not of monozygotic, twins.Generation XXI was funded by Programa Operacional de Saúde (Regional Department of Ministry of Health). It has support from the Portuguese Foundation for Science and Technology (FCT) and from the Calouste Gulbenkian Foundation.An individual grant to Braga S (SFRH/BD/120500/2016) by the Portuguese Foundation for Science and Technology (FCT) is gratefully acknowledged.This work was financed by FEDER (Fundo Europeu de Desenvolvimento Regional) funds through the COMPETE 2020 – Operacional Programme for Competitiveness and Internationalisation (POCI), Portugal 2020, and by Portuguese funds through FCT – Fundação para a Ciência e a Tecnologia/Ministério da Ciência, Tecnologia e Ensino Superior in the framework of the project PTDC/MEC-MCI/29777/2017/POCI-01-0145-FEDER-029777
Growth factor restriction impedes progression of wound healing following cataract surgery: identification of VEGF as a putative therapeutic target
Secondary visual loss occurs in millions of patients due to a wound-healing response, known as posterior capsule opacification (PCO), following cataract surgery. An intraocular lens (IOL) is implanted into residual lens tissue, known as the capsular bag, following cataract removal. Standard IOLs allow the anterior and posterior capsules to become physically connected. This places pressure on the IOL and improves contact with the underlying posterior capsule. New open bag IOL designs separate the anterior capsule and posterior capsules and further reduce PCO incidence. It is hypothesised that this results from reduced cytokine availability due to greater irrigation of the bag. We therefore explored the role of growth factor restriction on PCO using human lens cell and tissue culture models. We demonstrate that cytokine dilution, by increasing medium volume, significantly reduced cell coverage in both closed and open capsular bag models. This coincided with reduced cell density and myofibroblast formation. A screen of 27 cytokines identified nine candidates whose expression profile correlated with growth. In particular, VEGF was found to regulate cell survival, growth and myofibroblast formation. VEGF provides a therapeutic target to further manage PCO development and will yield best results when used in conjunction with open bag IOL designs
Transcriptional adaptation of Mycobacterium tuberculosis within macrophages: Insights into the phagosomal environment
Little is known about the biochemical environment in phagosomes harboring an infectious agent. To assess the state of this organelle we captured the transcriptional responses of Mycobacterium tuberculosis (MTB) in macrophages from wild-type and nitric oxide (NO) synthase 2–deficient mice before and after immunologic activation. The intraphagosomal transcriptome was compared with the transcriptome of MTB in standard broth culture and during growth in diverse conditions designed to simulate features of the phagosomal environment. Genes expressed differentially as a consequence of intraphagosomal residence included an interferon � – and NO-induced response that intensifies an iron-scavenging program, converts the microbe from aerobic to anaerobic respiration, and induces a dormancy regulon. Induction of genes involved in the activation and �-oxidation of fatty acids indicated that fatty acids furnish carbon and energy. Induction of �E-dependent, sodium dodecyl sulfate–regulated genes and genes involved in mycolic acid modification pointed to damage and repair of the cell envelope. Sentinel genes within the intraphagosomal transcriptome were induced similarly by MTB in the lungs of mice. The microbial transcriptome thus served as a bioprobe of the MTB phagosomal environment
Homological algebra for osp(1/2n)
We discuss several topics of homological algebra for the Lie superalgebra
osp(1|2n). First we focus on Bott-Kostant cohomology, which yields classical
results although the cohomology is not given by the kernel of the Kostant
quabla operator. Based on this cohomology we can derive strong
Bernstein-Gelfand-Gelfand resolutions for finite dimensional osp(1|2n)-modules.
Then we state the Bott-Borel-Weil theorem which follows immediately from the
Bott-Kostant cohomology by using the Peter-Weyl theorem for osp(1|2n). Finally
we calculate the projective dimension of irreducible and Verma modules in the
category O
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Nanoindentation Of Si Nanostructures: Buckling And Friction At Nanoscales
A nanoindentation system was employed to characterize mechanical properties of silicon nanolines (SiNLs), which were fabricated by an anisotropic wet etching (AWE) process. The SiNLs had the linewidth ranging from 24 nm to 90 nm, having smooth and vertical sidewalls and the aspect ratio (height/linewidth) from 7 to 18. During indentation, a buckling instability was observed at a critical load, followed by a displacement burst without a load increase, then a full recovery of displacement upon unloading. This phenomenon was explained by two bucking modes. It was also found that the difference in friction at the contact between the indenter and SiNLs directly affected buckling response of these nanolines. The friction coefficient was estimated to be in a range of 0.02 to 0.05. For experiments with large indentation displacements, irrecoverable indentation displacements were observed due to fracture of Si nanolines, with the strain to failure estimated to be from 3.8% to 9.7%. These observations indicated that the buckling behavior of SiNLs depended on the combined effects of load, line geometry, and the friction at contact. This study demonstrated a valuable approach to fabrication of well-defined Si nanoline structures and the application of the nanoindentation method for investigation of their mechanical properties at the nanoscale.Microelectronics Research Cente
Antibacterial activity of whole plant extract of Marrubium vulgare
The antibacterial activity of the methanolic extract of Marrubium vulgare whole plant was tested by disc diffusion method. Zones of Inhibition produced by methanolic extract in a dose of 50, 100, 200, 400 and600 mg/ml against selected strains was measured and compared with those of standard discs of antibiotic ciprofloxacin (10 ìg/ml)
Modulation of a surface plasmon-polariton resonance by sub-terahertz diffracted coherent phonons
Coherent sub-THz phonons incident on a gold grating that is deposited on a
dielectric substrate undergo diffraction and thereby induce an alteration of
the surface plasmon-polariton resonance. This results in efficient
high-frequency modulation (up to 110 GHz) of the structure's reflectivity for
visible light in the vicinity of the plasmon-polariton resonance. High
modulation efficiency is achieved by designing a periodic nanostructure which
provides both plasmon-polariton and phonon resonances. Our theoretical analysis
shows that the dynamical alteration of the plasmon-polariton resonance is
governed by modulation of the slit widths within the grating at the frequencies
of higher-order phonon resonances.Comment: 5 pages, 4 figure
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