Lawson criterion for ignition exceeded in an inertial fusion experiment

For more than half a century, researchers around the world have been engaged in attempts to achieve fusion ignition as a proof of principle of various fusion concepts. Following the Lawson criterion, an ignited plasma is one where the fusion heating power is high enough to overcome all the physical processes that cool the fusion plasma, creating a positive thermodynamic feedback loop with rapidly increasing temperature. In inertially confined fusion, ignition is a state where the fusion plasma can begin "burn propagation" into surrounding cold fuel, enabling the possibility of high energy gain. While "scientific breakeven" (i.e., unity target gain) has not yet been achieved (here target gain is 0.72, 1.37 MJ of fusion for 1.92 MJ of laser energy), this Letter reports the first controlled fusion experiment, using laser indirect drive, on the National Ignition Facility to produce capsule gain (here 5.8) and reach ignition by nine different formulations of the Lawson criterion

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

Auto-avaliação de saúde bucal em idosos: análise com base em modelo multidimensional Objective and subjective factors related to self-rated oral health among the elderly

Propôs-se investigar fatores associados à auto-avaliação negativa da saúde bucal. Idosos, participantes do inquérito de saúde bucal do Ministério da Saúde, 2002-2003, que auto-avaliaram sua saúde bucal como ruim/péssima foram comparados aos que a auto-avaliaram como ótima/boa/regular usando-se razões de prevalências (RP) com base na regressão de Poisson. A minoria (870 - 17%) auto-avaliou sua saúde bucal negativamente. A auto-avaliação negativa foi menor entre aqueles com 1-9 dentes e edentados, maior entre pardos/negros/índios, que nunca usaram serviços, que apresentavam alterações de tecidos moles, que relataram pouca e média/muita dor, que auto-avaliaram sua aparência e mastigação como regular ou ruim/péssima, entre os que relataram seus relacionamentos sociais pouco ou muito afetados pelas condições bucais e entre os que avaliavam necessitar de tratamento bucal. Apesar das precárias condições bucais, a maioria auto-avaliou positivamente sua saúde bucal. Condições subjetivas estiveram mais fortemente associadas do que as objetivas. Os resultados sugerem iniqüidade e permitem orientar políticas públicas que objetivem saúde bucal e qualidade de vida.<br>The aim of this study was to investigate factors associated with negative self-rated oral health. Elderly subjects from the Brazilian Ministry of Health's oral health survey (2002-2003) who rated their own oral health as bad or very bad were compared to those who rated their oral health as excellent, good, or fair, using prevalence ratios based on Poisson regression. The minority (870; 17%) gave their own oral health a negative rating. Negative self-rated oral health was less prevalent among those with 1-9 teeth and the edentulous, and more prevalent among blacks, mixed-race, and indigenous, those who had never used dental service, with soft tissue alterations, who reported little pain or medium to intense pain, rated their own appearance and chewing as fair or bad or very bad, reported that their oral health limited their social interaction a little or considerably, and reported needing dental treatment (PR = 1,47; 95%CI: 1.20-1.79). Despite their precarious oral conditions, the majority gave their oral health a positive rating. Subjective conditions were more heavily associated with self-rated oral health than were objective conditions. The findings suggest unequal oral health conditions and allow orienting public policies aimed at oral health and quality of life

Search for lensing signatures in the gravitational-wave observations from the first half of LIGO-Virgo's third observing run

We search for signatures of gravitational lensing in the gravitational-wave signals from compact binary coalescences detected by Advanced LIGO and Advanced Virgo during O3a, the first half of their third observing run. We study: 1) the expected rate of lensing at current detector sensitivity and the implications of a non-observation of strong lensing or a stochastic gravitational-wave background on the merger-rate density at high redshift; 2) how the interpretation of individual high-mass events would change if they were found to be lensed; 3) the possibility of multiple images due to strong lensing by galaxies or galaxy clusters; and 4) possible wave-optics effects due to point-mass microlenses. Several pairs of signals in the multiple-image analysis show similar parameters and, in this sense, are nominally consistent with the strong lensing hypothesis. However, taking into account population priors, selection effects, and the prior odds against lensing, these events do not provide sufficient evidence for lensing. Overall, we find no compelling evidence for lensing in the observed gravitational-wave signals from any of these analyses

Search for Lensing Signatures in the Gravitational-Wave Observations from the First Half of LIGO-Virgo's Third Observing Run

We search for signatures of gravitational lensing in the gravitational-wave signals from compact binary coalescences detected by Advanced Laser Interferometer Gravitational-wave Observatory (LIGO) and Advanced Virgo during O3a, the first half of their third observing run. We study: (1) the expected rate of lensing at current detector sensitivity and the implications of a non-observation of strong lensing or a stochastic gravitational-wave background on the merger-rate density at high redshift; (2) how the interpretation of individual high-mass events would change if they were found to be lensed; (3) the possibility of multiple images due to strong lensing by galaxies or galaxy clusters; and (4) possible wave-optics effects due to point-mass microlenses. Several pairs of signals in the multiple-image analysis show similar parameters and, in this sense, are nominally consistent with the strong lensing hypothesis. However, taking into account population priors, selection effects, and the prior odds against lensing, these events do not provide sufficient evidence for lensing. Overall, we find no compelling evidence for lensing in the observed gravitational-wave signals from any of these analyses

Observation of Gravitational Waves from the Coalescence of a 2.5–4.5 M _⊙ Compact Object and a Neutron Star

Abstract We report the observation of a coalescing compact binary with component masses 2.5–4.5 M ⊙ and 1.2–2.0 M ⊙ (all measurements quoted at the 90% credible level). The gravitational-wave signal GW230529_181500 was observed during the fourth observing run of the LIGO–Virgo–KAGRA detector network on 2023 May 29 by the LIGO Livingston observatory. The primary component of the source has a mass less than 5 M ⊙ at 99% credibility. We cannot definitively determine from gravitational-wave data alone whether either component of the source is a neutron star or a black hole. However, given existing estimates of the maximum neutron star mass, we find the most probable interpretation of the source to be the coalescence of a neutron star with a black hole that has a mass between the most massive neutron stars and the least massive black holes observed in the Galaxy. We provisionally estimate a merger rate density of 55 − 47 + 127 Gpc − 3 yr − 1 for compact binary coalescences with properties similar to the source of GW230529_181500; assuming that the source is a neutron star–black hole merger, GW230529_181500-like sources may make up the majority of neutron star–black hole coalescences. The discovery of this system implies an increase in the expected rate of neutron star–black hole mergers with electromagnetic counterparts and provides further evidence for compact objects existing within the purported lower mass gap.</jats:p