Worm blobs as entangled living polymers:From topological active matter to flexible soft robot collectives

Recently, the study of long, slender living worms has gained attention due to their unique ability to form highly entangled physical structures, exhibiting emergent behaviors. These organisms can assemble into an active three-dimensional soft entity referred to as the “blob”, which exhibits both solid-like and liquid-like properties. This blob can respond to external stimuli such as light, to move or change shape. In this perspective article, we acknowledge the extensive and rich history of polymer physics, while illustrating how these living worms provide a fascinating experimental platform for investigating the physics of active, polymer-like entities. The combination of activity, long aspect ratio, and entanglement in these worms gives rise to a diverse range of emergent behaviors. By understanding the intricate dynamics of the worm blob, we could potentially stimulate further research into the behavior of entangled active polymers, and guide the advancement of synthetic topological active matter and bioinspired tangling soft robot collectives.</p

Anti-diarrhoeal, anti ulcer and antimicrobial activities of leaves of Bougainvillea glabra Choisy

Con el fin de evaluar científicamente algunos de los usos tradicionales de la buganvilla (Bougainvillea glabra Choisy), se realizó el presente estudio para examinar los efectos antidiarreicos, antiulcerosos y antimicrobianos del extracto acuoso, etanólico y acetónico de sus hojas. Se probó la actividad antidiarreica en un modelo de diarrea inducida con aceite de ricino en ratas y se utilizó loperamida (3 mg/kg) como estándar de referencia. Se determinó la acción antiulcerosa mediante un modelo de úlcera inducida con alcohol y se utilizó omeprazol (10 mg/kg) como estándar. Ambos estudios se realizaron con dos niveles de dosis, 200 mg/kg y 400 mg/kg, respectivamente. La actividad antimicrobiana se estudió mediante un método de difusión en disco con una concentración de 500 μg/disco de extracto, utilizando ofl oxacina (5 μg/disco) como estándar. Los organismos utilizados fueron Escherichia coli, Bacillus subtilis, Klebsiella pneumoniae, Staphylococcus aureus y Proteus vulgaris, y se determinó la zona de inhibición. Los extractos de plantas mostraron una significativa acción antidiarreica, antiulcerosa y antimicrobiana en el presente estudio. Los resultados obtenidos corroboran lo sostenido por los profesionales de la medicina locales.In order to scientifically appraise some of the folkloric uses of Bougainvillea glabra Choisy, the present study was undertaken to examine the anti-diarrhoeal, antiulcer and antimicrobial activities of acetone, ethanolic and aqueous extract of leaves. Anti-diarrhoeal activity was tested in Castor oil induced diarrhea model using rats and Loperamide (3 mg/kg) was used as reference standard. The antiulcer activity was determined using alcohol induced ulcer model and Omeprazole 10 mg/ kg was used as the standard. Both the studies were carried out at two dose level, 200 mg/kg and 400 mg/kg respectively. Antimicrobial activity was done by disc diffusion method at a concentration of 500 μg/disc of the extract, using ofl oxacin (5 μg/disc) as the standard. The organisms used were Escherichia coli, Bacillus subtilis, Klebsiella pneumoniae, Staphylococcus aureus and Proteus vulgaris and the zone of inhibition was determined. The plant extracts showed significant anti-diarrhoeal, antiulcer and antimicrobial activities in the present study. The results obtained support the claim of local medical practitioners

Global gene expression analysis of pigeonpea with male sterility conditioned by A 2 cytoplasm

Cytoplasmic male sterility(CMS), a maternally inherited trait, provides a promising means to harness yield gains associated with hybrid vigor. In pigeonpea [Cajanus cajan (L.) Huth], nine types of sterility-inducing cytoplasm have been reported, of which A2 and A4 have been successfully deployed in hybrid breeding. Unfortunately, molecular mechanism of the CMS trait is poorly understood because of limited research invested. More recently, an association between a mitochondrial gene (nad7) and A4-CMS has been demonstrated in pigeonpea; however, the mechanism underlying A2-CMS still remains obscure. The current investigation aimed to analyze the differences in A2-CMS line (ICPL 88039A) and its isogenic maintainer line (ICPL 88039B) at transcriptome level using next-generation sequencing. Gene expression profiling uncovered a set of 505 genes that showed altered expression in response to CMS, of which, 412 genes were upregulated while 93 were downregulated in the fertile maintainer line vs. the CMS line. Further, gene ontology (GO), Kyoto Encyclopedia of Genes and Genomes (KEGG), and protein–protein interaction (PPI) network analyses revealed association of CMS in pigeonpea with four major pathways: glucose and lipid metabolism, ATP production, pollen development and pollen tube growth, and reactive oxygen species (ROS) scavenging. Patterns of digital gene expression were confirmed by quantitative real-time polymerase chain reaction (qRT-PCR) of six candidate genes. This study elucidates candidate genes and metabolic pathways having potential associations with pollen development and male sterility in pigeonpea A2-CMS. New insights on molecular mechanism of CMS trait in pigeonpea will be helpful to accelerate heterosis utilization for enhancing productivity gains in pigeonpea

Search for gravitational waves from Scorpius X-1 in the second Advanced LIGO observing run with an improved hidden Markov model

We present results from a semicoherent search for continuous gravitational waves from the low-mass x-ray binary Scorpius X-1, using a hidden Markov model (HMM) to track spin wandering. This search improves on previous HMM-based searches of LIGO data by using an improved frequency domain matched filter, the J-statistic, and by analyzing data from Advanced LIGO's second observing run. In the frequency range searched, from 60 to 650 Hz, we find no evidence of gravitational radiation. At 194.6 Hz, the most sensitive search frequency, we report an upper limit on gravitational wave strain (at 95% confidence) of h095%=3.47×10-25 when marginalizing over source inclination angle. This is the most sensitive search for Scorpius X-1, to date, that is specifically designed to be robust in the presence of spin wandering. © 2019 American Physical Society

Erratum: "A Gravitational-wave Measurement of the Hubble Constant Following the Second Observing Run of Advanced LIGO and Virgo" (2021, ApJ, 909, 218)

[no abstract available

Search for Tensor, Vector, and Scalar Polarizations in the Stochastic Gravitational-Wave Background

The detection of gravitational waves with Advanced LIGO and Advanced Virgo has enabled novel tests of general relativity, including direct study of the polarization of gravitational waves. While general relativity allows for only two tensor gravitational-wave polarizations, general metric theories can additionally predict two vector and two scalar polarizations. The polarization of gravitational waves is encoded in the spectral shape of the stochastic gravitational-wave background, formed by the superposition of cosmological and individually unresolved astrophysical sources. Using data recorded by Advanced LIGO during its first observing run, we search for a stochastic background of generically polarized gravitational waves. We find no evidence for a background of any polarization, and place the first direct bounds on the contributions of vector and scalar polarizations to the stochastic background. Under log-uniform priors for the energy in each polarization, we limit the energy densities of tensor, vector, and scalar modes at 95% credibility to Ω0T<5.58×10-8, Ω0V<6.35×10-8, and Ω0S<1.08×10-7 at a reference frequency f0=25 Hz. © 2018 American Physical Society

Search for Gravitational Waves Associated with Gamma-Ray Bursts Detected by Fermi and Swift during the LIGO-Virgo Run O3b

We search for gravitational-wave signals associated with gamma-ray bursts (GRBs) detected by the Fermi and Swift satellites during the second half of the third observing run of Advanced LIGO and Advanced Virgo (2019 November 1 15:00 UTC-2020 March 27 17:00 UTC). We conduct two independent searches: A generic gravitational-wave transients search to analyze 86 GRBs and an analysis to target binary mergers with at least one neutron star as short GRB progenitors for 17 events. We find no significant evidence for gravitational-wave signals associated with any of these GRBs. A weighted binomial test of the combined results finds no evidence for subthreshold gravitational-wave signals associated with this GRB ensemble either. We use several source types and signal morphologies during the searches, resulting in lower bounds on the estimated distance to each GRB. Finally, we constrain the population of low-luminosity short GRBs using results from the first to the third observing runs of Advanced LIGO and Advanced Virgo. The resulting population is in accordance with the local binary neutron star merger rate. © 2022. The Author(s). Published by the American Astronomical Society