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Search for Gravitational Wave Memory in PPTA and EPTA Data: A Complete Signal Model
No full textWe perform searches for gravitational wave memory in the data of two major Pulsar Timing Array (PTA) experiments located in Europe and Australia. Supermassive black hole binaries (SMBHBs) are the primary sources of gravitational waves in PTA experiments. We develop and carry out the first search for late inspirals and mergers of these sources based on full numerical relativity waveforms with null (nonlinear) gravitational wave memory. Additionally, we search for generic bursts of null gravitational wave memory, exploring possibilities of reducing the computational cost of these searches through kernel density and normalizing flow approximation of the posteriors. We rule out the mergers of SMBHBs with a chirp mass of 10^10 Solar Mass up to 700 Mpc over 18 years of observation at 95% credibility. We rule out the observation of generic displacement memory bursts with strain amplitudes > 10^-14 in brief periods of the observation time but across the sky, or over the whole observation time but for certain preferred sky positions, at 95%$credibility
Optimizing Magnesium Uptake in Lacticaseibacillus Rhamnosus To Advance Nutribiotic Strategies
No full textMagnesium is an essential mineral involved in more than 300 enzymatic reactions, including protein synthesis, neuromuscular function, and blood pressure regulation. Recent studies have highlighted the role of probiotics, beneficial microorganisms in the human gut, in enhancing mineral absorption. However, the interaction between magnesium and probiotic strains remains poorly understood. This study aimed to investigate the capacity of Lacticaseibacillus rhamnosus ATCC 53,103 to uptake and internalize magnesium ions, using MgSO₄ as a supplementation source. The bacterium was cultivated in MRS medium with varying concentrations of MgSO₄ (0, 0.1444, 0.722, and 1.444 g/L) over seven days. Quantitative analysis revealed that at 0.722 g/L MgSO₄, intracellular magnesium accumulation peaked at 0.7 mg/dL by Day 3, representing a 7-fold increase compared to the control (0.1 mg/dL). Scanning and transmission electron microscopy indicated essential morphological changes, including ruffled cell surfaces and enhanced ribosomal visibility. These findings suggest that L. rhamnosus can internalize magnesium under enriched conditions, supporting its potential as a microbial carrier for nutribiotic applications. This work contributes to the growing field of mineral-microbe interactions and may inform the development of probiotic-based strategies to improve magnesium bioaccessibility in the human gut
From stealthing to the «pill lie»: deceptive practices concerning reproductive and protective measures in sexual encounters
No full textPlasmon dynamics in graphene
No full textPlasmons are collective oscillations of mobile electrons. Using terahertz spacetime metrology, we probe plasmon dynamics of mono- and bi-layer graphene. In both systems, the experimentally measured Drude weight systematically exceeds the prediction based on non-interacting electronic system. This enhancement is most pronounced at ultra-low carrier densities. We attribute the observed deviation to pseudospin dynamics of the Dirac fermions in multi-layer graphene, which leads to a breakdown of Galilean invariance. Our results establish that pseudospin structure of the single-particle electronic wave function can directly govern collective excitations, with implications that extend beyond graphene to a broad class of quantum materials
Finite-momentum Cooper plasmons in superconducting terahertz microcavities
No full textThe phase mode of a superconductor's order parameter encodes fundamental information about pairing and dissipation, but is typically inaccessible at low frequencies due to the Anderson-Higgs mechanism. Superconducting samples thinner than the London penetration depth, however, support a gapless phase mode whose dispersion can be reshaped by a proximal screening layer. Here, we theoretically and experimentally show that this screened phase mode in a superconducting thin film integrated into on-chip terahertz circuitry naturally forms a superconducting microcavity that hosts resonant finite-momentum standing waves of supercurrent density, which we term Cooper plasmons. We measure two Cooper plasmons in a superconducting NbN microcavity and demonstrate that their resonance frequencies and linewidths independently report the density of participating carriers and plasmon's dissipation at finite momenta. Our results reveal an emergent collective mode of an integrated superconductor-circuit system and establish design principles for engineering or suppressing Cooper plasmons in superconducting terahertz devices and circuits
A framework for LISA population inference
No full textThe Laser Interferometer Space Antenna (LISA) is expected to have a source rich data stream containing signals from large numbers of many different types of source. This will include both individually resolvable signals and overlapping stochastic backgrounds, a regime intermediate between current ground-based detectors and pulsar timing arrays. The resolved sources and backgrounds will be fitted together in a high dimensional Global Fit. To extract information about the astrophysical populations to which the sources belong, we need to decode the information in the Global Fit, which requires new methodology that has not been required for the analysis of current gravitational wave detectors. Here, we %start that development, presenting present a hierarchical Bayesian framework to infer the properties of astrophysical populations directly from the output of a LISA Global Fit, consistently accounting for information encoded in both the resolved sources and the unresolved background. Using a simplified model of the Global Fit, we illustrate how the interplay between resolved and unresolved components affects population inference and highlight the impact of data analysis choices, such as the signal-to-noise threshold for resolved sources, on the results. Our approach provides a practical foundation for population inference using LISA data
Probing millisecond magnetar formation in binary neutron star mergers through X-ray follow-up of gravitational wave alerts
No full textThe nature of the remnant of a binary neutron star (BNS) merger is uncertain. Though certainly a black hole (BH) in the cases of the most massive BNSs, X-ray lightcurves from gamma-ray burst (GRB) afterglows suggest a neutron star (NS) as a viable candidate for both the merger remnant as well as the central engine of these transients. When jointly observed with gravitational waves (GWs), X-ray lightcurves from BNS merger events could provide critical constraints on the remnant's nature. We aim to assess the current and future capabilities to detect a NS remnant through X-ray observations following GW detections. To this end, we simulate GW signals from BNS mergers and the subsequent X-ray emission from newborn millisecond magnetars. The GW detectability is modeled for both current and next-generation interferometers, while the X-ray emission is reproduced using a dedicated numerical code that models magnetar spin-down and ejecta dynamics informed by numerical-relativity simulations. In our simulations, 2% - 16% of BNS mergers form millisecond magnetars. Among these, up to 70% could be detectable, amounting to up to 1 millisecond magnetar detection per year with SVOM/MXT-like instruments during the LIGO Virgo KAGRA LIGO India (LVKI) O5 run, with optimal detectability occurring about 2 hours post-merger. For next-generation GW interferometers, this rate could increase by up to three orders of magnitude, with peak detectability 3 to 4 hours post-merger. We also explore how the magnetar's magnetic field strength and observer viewing angle affect detectability and discuss optimized observational strategies. Although more likely with upcoming GW interferometers, detecting the spin-down emission of a millisecond magnetar may already be within reach, warranting sustained theoretical and observational efforts given the profound implications for mergers, GRBs, and NS physics of a single detection
Autophagy regulation by phase separation, avidity, and wetting
No full textAutophagy enables cells to selectively degrade a wide range of macromolecules, and how this process achieves spatial precision within the densely packed cytosol is an active area of investigation. Recent advances suggest that phase separation provides a crucial organizational framework that converts autophagy into a spatiotemporally coordinated and self-organizing process. Biomolecular condensates formed by phase separation can create high-avidity binding platforms between autophagy receptors, scaffold proteins, and the cargo that stabilize transient molecular contacts. The formation of such condensates specifies the cargo and initiates autophagosome formation at defined cellular locations. Simultaneously, physical properties such as wetting govern how condensates interact with membranes, and thus influence engulfment efficiency. Viewing autophagy through the lens of condensate physics not only explains its molecular specificity but also highlights new therapeutic opportunities