10 research outputs found

    Testing the multipole structure of compact binaries using gravitational wave observations

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    We propose a novel method to test the consistency of the multipole moments of compact binary systems with the predictions of general relativity (GR). The multipole moments of a compact binary system, known in terms of symmetric and trace-free tensors, are used to calculate the gravitational waveforms from compact binaries within the post-Newtonian (PN) formalism. For nonspinning compact binaries, we derive the gravitational wave phasing formula, in the frequency domain, parametrizing each PN order term in terms of the multipole moments which contribute to that order. Using GW observations, this parametrized multipolar phasing would allow us to derive the bounds on possible departures from the multipole structure of GR and hence constrain the parameter space of alternative theories of gravity. We compute the projected accuracies with which the second-generation ground-based detectors, such as the Advanced Laser Interferometer Gravitational-wave Observatory (LIGO), the third-generation detectors such as the Einstein Telescope and Cosmic Explorer, as well as the space-based detector Laser Interferometer Space Antenna (LISA) will be able to measure these multipole parameters. We find that while Advanced LIGO can measure the first two or three multipole coefficients with good accuracy, Cosmic Explorer and the Einstein Telescope may be able to measure the first four multipole coefficients which enter the phasing formula. Intermediate-mass-ratio inspirals, with mass ratios of several tens, in the frequency band of the planned space-based LISA mission should be able to measure all seven multipole coefficients which appear in the 3.5PN phasing formula. Our finding highlights the importance of this class of sources for probing the strong-field gravity regime. The proposed test will facilitate the first probe of the multipolar structure of Einstein’s general relativity

    Robust estimation of bacterial cell count from optical density

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    Optical density (OD) is widely used to estimate the density of cells in liquid culture, but cannot be compared between instruments without a standardized calibration protocol and is challenging to relate to actual cell count. We address this with an interlaboratory study comparing three simple, low-cost, and highly accessible OD calibration protocols across 244 laboratories, applied to eight strains of constitutive GFP-expressing E. coli. Based on our results, we recommend calibrating OD to estimated cell count using serial dilution of silica microspheres, which produces highly precise calibration (95.5% of residuals <1.2-fold), is easily assessed for quality control, also assesses instrument effective linear range, and can be combined with fluorescence calibration to obtain units of Molecules of Equivalent Fluorescein (MEFL) per cell, allowing direct comparison and data fusion with flow cytometry measurements: in our study, fluorescence per cell measurements showed only a 1.07-fold mean difference between plate reader and flow cytometry data

    The MeerKAT Galaxy Cluster Legacy Survey: I. Survey overview and highlights

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    Please abstract in the article.The South African Radio Astronomy Observatory (SARAO), the National Research Foundation (NRF), the National Radio Astronomy Observatory, US National Science Foundation, the South African Research Chairs Initiative of the DSI/NRF, the SARAO HCD programme, the South African Research Chairs Initiative of the Department of Science and Innovation.http://www.aanda.orghj2022Physic

    Biological evaluation of (3β)-STIGMAST-5-EN-3-OL as potent anti-diabetic agent in regulating glucose transport using in vitro model

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    AbstractAimInsulin resistance is characterized by alterations in insulin signaling components thereby resulting in reduced glucose uptake. The mechanistic role of (3β)-stigmast-5-en-3-ol in augmenting glucose uptake to overcome insulin resistance is deciphered in this study.Main methodsL6 myotubes, rat skeletal muscle model have been used to check the effect of (3β)-stigmast-5-en-3-ol, a plant phytosterol isolated from the ethyl acetate extract of Adathoda vasica on glucose transport. The influence of (3β)-stigmast-5-en-3-ol on various cellular targets of insulin signaling cascade has been evaluated using inhibitors on glucose uptake as well as gene and protein expression to unravel the mechanistic action in triggering glucose uptake.Results(3β)-stigmast-5-en-3-ol promoted glucose uptake in a dose dependent manner under insulin resistant condition. As assessed by inhibitor studies using Genistein (IRTK inhibitor) and Wortmannin (PI3K inhibitor), gene expression and protein expression studies using specific primers and antibodies, an activation of IR-β, IRS-1, PI3K, AKT/PKB, PKC by both the crude and (3β)-stigmast-5-en-3-ol were observed. This suggested that (3β)-stigmast-5-en-3-ol induced glucose uptake functions through the PI3K dependent pathway in L6 myotubes. Both, the crude and (3β)-stigmast-5-en-3-ol activates GLUT 4 transport (evident from increased mRNA levels and redistribution of GLUT4 from intracellular membrane to plasma membrane through translocation studies). Confocal microscopy revealed a substantial increase in redistribution of FITC tagged GLUT4 throughout the cells.ConclusionOur results emphasize the insulin-like effect of (3β)-stigmast-5-en-3-ol in stimulating glucose transport in vitro and provide evidence in its beneficial role possessing antidiabetic property apart from its existing cholesterol lowering efficacy

    Proceedings of International Conference on Women Researchers in Electronics and Computing

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    This proceeding contains articles on the various research ideas of the academic community and practitioners presented at the international conference, “Women Researchers in Electronics and Computing” (WREC’2021). WREC'21 was organized in online mode by Dr. B R Ambedkar National Institute of Technology, Jalandhar (Punjab), INDIA during 22 – 24 April 2021. This conference was conceptualized with an objective to encourage and motivate women engineers and scientists to excel in science and technology and to be the role models for young girls to follow in their footsteps. With a view to inspire women engineers, pioneer and successful women achievers in the domains of VLSI design, wireless sensor networks, communication, image/ signal processing, machine learning, and emerging technologies were identified from across the globe and invited to present their work and address the participants in this women oriented conference. Conference Title: International Conference on Women Researchers in Electronics and ComputingConference Acronym: WREC'21Conference Date: 22–24 April 2021Conference Location: Online (Virtual Mode)Conference Organizers: Department of Electronics and Communication Engineering, Dr. B. R. Ambedkar National Institute of Technology, Jalandhar, Punjab, INDI
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