281 research outputs found
Novel Antimicrobial Surfaces to Defeat COVID-19 Transmission
Antimicrobial surface coatings function as a contact biocide and are extensively used to prevent the growth and transmission of pathogens on environmental surfaces. Currently, scientists and researchers are intensively working to develop antimicrobial, antiviral coating solutions that would efficiently impede/stop the contagion of COVID-19 via surface contamination. Herein we present a flavonoid-based antimicrobial surface coating fabricated by laser processing that has the potential to eradicate COVID-19 contact transmission. Quercetin-containing coatings showed better resistance to microbial colonization than antibiotic–containing ones
Angiogenesis in old-aged subjects after ischemic stroke: a cautionary note for investigators
Angiogenesis represents a form of neovascularisation of exceptional importance in numerous pathological conditions including stroke. In this context it is directly related to neuroregeneration which is seen in close proximity. However, numerous experimental data have been drawn from studies that have ignored the age criterion. This is extremely important as angiogenesis is different in young versus old subjects. Extrapolating data obtained from studies performed in young subjects or "in vitro" to old-age patients could lead to inexact conclusions since the dynamics of angiogenesis is age-dependent
Observation of A Kilogram-Scale Oscillator Near Its Quantum Ground State
We introduce a novel cooling technique capable of approaching the quantum ground state of a kilogram-scale system-an interferometric gravitational wave detector. The detectors of the Laser Interferometer Gravitational-wave Observatory (LIGO) operate within a factor of 10 of the standard quantum limit (SQL), providing a displacement sensitivity of 10-18 m in a 100 Hz band centered on 150 Hz. With a new feedback strategy, we dynamically shift the resonant frequency of a 2.7 kg pendulum mode to lie within this optimal band, where its effective temperature falls as low as 1.4μK, and its occupation number reaches about 200 quanta. This work shows how the exquisite sensitivity necessary to detect gravitational waves can be made available to probe the validity of quantum mechanics on an enormous mass scale
Search for Gravitational Waves from Low Mass Binary Coalescences In the First Year of LIGO\u27s S5 Data
We have searched for gravitational waves from coalescing low mass compact binary systems with a total mass between 2M and 35 and a minimum component mass of 1M using data from the first year of the fifth science run of the three LIGO detectors, operating at design sensitivity. Depending on the mass, we are sensitive to coalescences as far as 150Mpc from the Earth. No gravitational-wave signals were observed above the expected background. Assuming a population of compact binary objects with a Gaussian mass distribution representing binary neutron star systems, black hole-neutron star binary systems, and binary black hole systems, we calculate the 90% confidence upper limit on the rate of coalescences to be 3.9×10-2yr-1L10-1, 1.1×10-2yr-1L10-1, and 2.5×10-3yr-1L10-1, respectively, where L10 is 1010 times the blue solar luminosity. We also set improved upper limits on the rate of compact binary coalescences per unit blue-light luminosity, as a function of mass
Search for High Frequency Gravitational-Wave Bursts In the First Calendar Year of LIGO\u27s Fifth Science Run
We present an all-sky search for gravitational waves in the frequency range 1 to 6 kHz during the first calendar year of LIGO\u27s fifth science run. This is the first untriggered LIGO burst analysis to be conducted above 3 kHz. We discuss the unique properties of interferometric data in this regime. 161.3 days of triple-coincident data were analyzed. No gravitational events above threshold were observed and a frequentist upper limit of 5.4year-1 on the rate of strong gravitational-wave bursts was placed at a 90% confidence level. Implications for specific theoretical models of gravitational-wave emission are also discussed
Search for Gravitational Wave Ringdowns from Perturbed Black Holes In LIGO S4 Data
According to general relativity a perturbed black hole will settle to a stationary configuration by the emission of gravitational radiation. Such a perturbation will occur, for example, in the coalescence of a black hole binary, following their inspiral and subsequent merger. At late times the waveform is a superposition of quasinormal modes, which we refer to as the ringdown. The dominant mode is expected to be the fundamental mode, l=m=2. Since this is a well-known waveform, matched filtering can be implemented to search for this signal using LIGO data. We present a search for gravitational waves from black hole ringdowns in the fourth LIGO science run S4, during which LIGO was sensitive to the dominant mode of perturbed black holes with masses in the range of 10M□ to 500M□, the regime of intermediate-mass black holes, to distances up to 300□Mpc. We present a search for gravitational waves from black hole ringdowns using data from S4. No gravitational wave candidates were found; we place a 90%-confidence upper limit on the rate of ringdowns from black holes with mass between 85M□ and 390M□ in the local universe, assuming a uniform distribution of sources, of 3.2×10-5yr-1Mpc-3=1.6×10-3yr- 1L10-1,where L10 is 1010 times the solar blue-light luminosity
Serviciul nefrologic pentru maturi în Republica Moldova (2000-2001)
Summary.
Nephrological medical service of adult population in Republic of Moldova (2000 -2001). A review
of nephrological medical service in adult population was carried out. There is a great awareness
due to the increasing in incidence of the renal diseases in Republic of Moldova. In our professional
view substantial recommendations to determine the changes that must be made in the field of
nephrological service were suggested
Searches for Gravitational Waves from Known Pulsars with Science Run 5 LIGO Data
We present a search for gravitational waves from 116 known millisecond and young pulsars using data from the fifth science run of the LIGO detectors. For this search, ephemerides overlapping the run period were obtained for all pulsars using radio and X-ray observations. We demonstrate an updated search method that allows for small uncertainties in the pulsar phase parameters to be included in the search. We report no signal detection from any of the targets and therefore interpret our results as upper limits on the gravitational wave signal strength. The most interesting limits are those for young pulsars. We present updated limits on gravitational radiation from the Crab pulsar, where the measured limit is now a factor of 7 below the spin-down limit. This limits the power radiated via gravitational waves to be less than 2% of the available spin-down power. For the X-ray pulsar J0537 - 6910 we reach the spin-down limit under the assumption that any gravitational wave signal from it stays phase locked to the X-ray pulses over timing glitches, and for pulsars J1913+1011 and J1952+3252 we are only a factor of a few above the spin-down limit. Of the recycled millisecond pulsars, several of the measured upper limits are only about an order of magnitude above their spin-down limits. For these our best (lowest) upper limit on gravitational wave amplitude is 2.3 × 10 -26 for J1603 - 7202 and our best (lowest) limit on the inferred pulsar ellipticity is 7.0 × 10-8 for J2124 - 3358
Search for Gravitational-Wave Bursts Associated with Gamma-Ray Bursts Using Data from LIGO Science Run 5 and Virgo Science Run 1
We present the results of a search for gravitational-wave bursts (GWBs) associated with 137 gamma-ray bursts (GRBs) that were detected by satellite-based gamma-ray experiments during the fifth LIGO science run and first Virgo science run. The data used in this analysis were collected from 2005 November 4 to 2007 October 1, and most of the GRB triggers were from the Swift satellite. The search uses a coherent network analysis method that takes into account the different locations and orientations of the interferometers at the three LIGO-Virgo sites. We find no evidence for GWB signals associated with this sample of GRBs. Using simulated short-duration (\u3c1 \u3es) waveforms, we set upper limits on the amplitude of gravitational waves associated with each GRB. We also place lower bounds on the distance to each GRB under the assumption of a fixed energy emission in gravitational waves, with a median limit of D ∼ 12 Mpc(E iso GW/0.01 M ⊙ c 2)1/2 for emission at frequencies around 150 Hz, where the LIGO-Virgo detector network has best sensitivity. We present astrophysical interpretations and implications of these results, and prospects for corresponding searches during future LIGO-Virgo runs
Search for Gravitational Waves from Compact Binary Coalescence In LIGO and Virgo Data from S5 and VSR1
We report the results of the first search for gravitational waves from compact binary coalescence using data from the Laser Interferometer Gravitational-wave Observatory (LIGO) and Virgo detectors. Five months of data were collected during the concurrent S5 (LIGO) and VSR1 (Virgo) science runs. The search focused on signals from binary mergers with a total mass between 2 and 35 M. No gravitational waves are identified. The cumulative 90%-confidence upper limits on the rate of compact binary coalescence are calculated for nonspinning binary neutron stars, black hole-neutron star systems, and binary black holes to be 8.7×10−3 yr−1L−1 10 , 2.2×10−3 yr−1L−1 10 , and 4.4×10−4 yr−1L−1 10 respectively, where L10 is 1010 times the blue solar luminosity. These upper limits are compared with astrophysical expectations
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