Search for gravitational-lensing signatures in the full third observing run of the LIGO-Virgo network

Gravitational lensing by massive objects along the line of sight to the source causes distortions of gravitational wave-signals; such distortions may reveal information about fundamental physics, cosmology and astrophysics. In this work, we have extended the search for lensing signatures to all binary black hole events from the third observing run of the LIGO--Virgo network. We search for repeated signals from strong lensing by 1) performing targeted searches for subthreshold signals, 2) calculating the degree of overlap amongst the intrinsic parameters and sky location of pairs of signals, 3) comparing the similarities of the spectrograms amongst pairs of signals, and 4) performing dual-signal Bayesian analysis that takes into account selection effects and astrophysical knowledge. We also search for distortions to the gravitational waveform caused by 1) frequency-independent phase shifts in strongly lensed images, and 2) frequency-dependent modulation of the amplitude and phase due to point masses. None of these searches yields significant evidence for lensing. Finally, we use the non-detection of gravitational-wave lensing to constrain the lensing rate based on the latest merger-rate estimates and the fraction of dark matter composed of compact objects

Search for eccentric black hole coalescences during the third observing run of LIGO and Virgo

Despite the growing number of confident binary black hole coalescences observed through gravitational waves so far, the astrophysical origin of these binaries remains uncertain. Orbital eccentricity is one of the clearest tracers of binary formation channels. Identifying binary eccentricity, however, remains challenging due to the limited availability of gravitational waveforms that include effects of eccentricity. Here, we present observational results for a waveform-independent search sensitive to eccentric black hole coalescences, covering the third observing run (O3) of the LIGO and Virgo detectors. We identified no new high-significance candidates beyond those that were already identified with searches focusing on quasi-circular binaries. We determine the sensitivity of our search to high-mass (total mass M>70 M⊙) binaries covering eccentricities up to 0.3 at 15 Hz orbital frequency, and use this to compare model predictions to search results. Assuming all detections are indeed quasi-circular, for our fiducial population model, we place an upper limit for the merger rate density of high-mass binaries with eccentricities 0<e≤0.3 at 0.33 Gpc−3 yr−1 at 90\% confidence level

Ultralight vector dark matter search using data from the KAGRA O3GK run

Among the various candidates for dark matter (DM), ultralight vector DM can be probed by laser interferometric gravitational wave detectors through the measurement of oscillating length changes in the arm cavities. In this context, KAGRA has a unique feature due to differing compositions of its mirrors, enhancing the signal of vector DM in the length change in the auxiliary channels. Here we present the result of a search for U(1)B−L gauge boson DM using the KAGRA data from auxiliary length channels during the first joint observation run together with GEO600. By applying our search pipeline, which takes into account the stochastic nature of ultralight DM, upper bounds on the coupling strength between the U(1)B−L gauge boson and ordinary matter are obtained for a range of DM masses. While our constraints are less stringent than those derived from previous experiments, this study demonstrates the applicability of our method to the lower-mass vector DM search, which is made difficult in this measurement by the short observation time compared to the auto-correlation time scale of DM

Towards the understanding of tetrahydroquinolines action in <i>Aedes aegypti</i>: larvicide or adulticide?

<p><i>Aedes aegypti</i> is an important vector of arboviruses such as dengue, yellow fever, chikungunya and Zika. Among the various types of insecticides used to combat this vector, the insect growth regulators have been developed and recommended for control of their larvae. In this work compounds with proven regulatory action, tetrahydroquinolines will be studied. These regulators act on the hormones responsible for the insect development. Ecdysone, one of the main hormones involved in this process has a specific receptor (EcR), where tetrahydroquinolines derivatives can bind, disrupting the normal action of this hormone, because they have structure similar to hormone 20-hydroxyecdysone (20E). In addition, studies show that this class of compounds interacts strongly in the potassium channel activated by calcium (BK channel). Thus, the goal is to study the action of compounds (tetrahydroquinolines) as insecticides and evaluate their larvicidal action (action on the ecdysone receptor) or adulticide (action on the BK channel) through homology modelling techniques, molecular docking and molecular dynamics simulations and aiming to propose a compound that presents both actions (larvicide / adulticide).</p

Structural, electronic and optical properties of Fe(III) complex with pyridine-2,6-dicarboxylic acid: A combined experimental and theoretical study

This paper describes the synthesis, as well the structural, electronic and optical properties of a novel complex of Fe(III) with pyridine-2,6-dicarboxylic acid (DPA). The complex was characterized by Fourier transform infrared (FT-IR) spectroscopy, Fourier transform Raman spectroscopy (FT-Raman), field emission scanning electron microscopy (FE-SEM), UV-Vis absorption spectroscopy and photoluminescence (PL) measurements. The chemical compositions were examined with an energy dispersive X-ray spectrometer (EDXS) analysis. First principle calculations at density functional theory (DFT) level have been carried out in order to understand the effects caused by structural distortions. The synthesized iron complex shows a molar ratio of 1:2 metal/ligand with an approximate octahedral configuration. Theoretical results derived from the analysis of molecular orbitals (MOs) and the electron density obtained from Quantum Theory of Atoms in Molecules (QTAIM) point out that the chemical bonds between oxygen and the iron atom in the Fe-DPA complex is predominantly electrostatic. In order to modeling the PL emissions, an energy profile associated to the variation of the dihedral angle (C-N-N-C) of the Fe-DPA complex, connecting the ground and excited electronic states, allows us to find a relationship between structural order-disorder effects with PL emissions. (C) 2014 Elsevier B.V. All rights reserved.Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES

Synthesis and in vitro evaluation of leishmanicidal activity of 7-hydroxy-4-phenylcoumarin derivatives

Eight coumarin derivatives (2–8) were synthesized from 7-hydroxy-4-phenylcoumarin 1 and were evaluated for their in vitro leishmanicidal activity against promastigote and amastigote forms of Leishmania amazonensis, as well their toxicity in murine macrophages. Compounds 4 and 7 showed the most significant results against promastigote forms of L. amazonensis. They were at least three-fold more active than 1 and Compound 4 was as effective as Amphotericin B. Compound 4, a 7-O-prenylated derivative, and 7, a tetra- O -acetyl-β- D -glucopyranosyl derivative, presented IC50 values of 21.35 and 10.03 µM against promastigote and IC50 values of 58.10 and 34.93 µM, respectively against amastigote forms. Furthermore, they do not cause toxicity in mammalian or Leishmania cells in vitro. This study shows that these coumarin derivatives are potential prototypes for the development of novel drugs with leishmanicidal activity