54 research outputs found
Atividade secretória de tubas uterinas com e sem patologia de porcas adultas nas fases folicular e luteÃnica
GW190814: gravitational waves from the coalescence of a 23 solar mass black hole with a 2.6 solar mass compact object
We report the observation of a compact binary coalescence involving a 22.2–24.3 Me black hole and a compact object with a mass of 2.50–2.67 Me (all measurements quoted at the 90% credible level). The gravitational-wave signal, GW190814, was observed during LIGO’s and Virgo’s third observing run on 2019 August 14 at 21:10:39 UTC and has a signal-to-noise ratio of 25 in the three-detector network. The source was localized to 18.5 deg2 at a distance of - + 241 45
41 Mpc; no electromagnetic counterpart has been confirmed to date. The source has the most unequal mass ratio yet measured with gravitational waves, - + 0.112 0.009 0.008, and its secondary component is either the lightest black hole or the heaviest neutron star ever discovered in a double compact-object system. The
dimensionless spin of the primary black hole is tightly constrained to �0.07. Tests of general relativity reveal no measurable deviations from the theory, and its prediction of higher-multipole emission is confirmed at high confidence. We estimate a merger rate density of 1–23 Gpc−3 yr−1 for the new class of binary coalescence sources
that GW190814 represents. Astrophysical models predict that binaries with mass ratios similar to this event can form through several channels, but are unlikely to have formed in globular clusters. However, the combination of mass ratio, component masses, and the inferred merger rate for this event challenges all current models of the formation and mass distribution of compact-object binaries
Recommended from our members
Bibliography of atomic and molecular excitation in heavy particle collisions, 1950--1975
This annotated bibliography lists published work on atomic and molecular excitation in heavy particle collisions for the period 1950 to 1975. Sources include scientific journals, abstract compilations, conference proceedings, books, and reports. The bibliography is arranged alphabetically by author. Each entry indicates whether the work was experimental or theoretical, what energy range was covered, and what reactants were investigated. Following the bibliographical listing are indexes of reactions and authors
PMS60 The Time Horizon Matters: Exploratory Results Varying the Time Horizon in Time Trade-Off and Standard Gamble Utility Elicitation
Recommended from our members
Use of Z-Pinch Techniques for Equation of State Applications
A principal goal of the shock physics program at Sandia is to establish a capability to make accurate equation of state (EOS) measurements on the Z pulsed radiation source. The Z accelerator is a source of intense x-ray radiation, which can be used to drive ablative shocks for EOS studies. With this source, ablative multi shocks can be produced to study materials over the range of interest to both weapons and ICF physics programs. In developing the capability to diagnose these types of studies on Z, techniques commonly used in conventional impact generated experimental were implemented. The primary diagnostic presently being used for this work is velocity interferometry, VISAR, which not only provides Hugoniot particle velocity measurements, but also measurements of non-shock EOS measurements, such as isentropic compression. In addition to VISAR capability, methods for measuring shock velocity have also been developed for shock studies on Z. When used in conjunction with the Rankine- Hugoniot jump conditions, material response at high temperatures and pressures can be inferred. Radiation in the Z accelerator is produced when approximately 18 MA are passed through a cylindrical wire array typically 20 to 50 mm in diameter and 10 to 20 mm in height. 200-300 wires with initial diameters on the order of 8 to 20 micron form, upon application of the current, a plasma shell, which is magnetically imploded until it collapses and stagnates on axis, forming a dense plasma emitter in the shape of a column, referred to as a" z pinch". The initial wire array and subsequent plasma pinch are confined within a metallic can, referred to as a primary hohlraum, which serves as both a current return path and a reflective surface to contain the radiation. Attached to openings in the primary hohlraum wall are smaller tubes referred to as secondaries. Multiple secondaries can be fielded on most experiments, which are the typical location for mounting EOS samples. In this configuration, the secondary S1 contains two separate VISAR probes for making velocity measurements at different material thicknesses. By correlating the resulting velocity profiles in time, a measurement of shock velocity can be determined. In addition, the velocity profiles provide the Hugoniot particle velocity after the records were impedance-matched. Secondaries S2 and S3 provide measurements of shock velocity using laser light reflected from steps. As the shock arrives at each of these surfaces, the surface reflectivity significantly decreases, which causes a sharp drop in return light. The shock velocity can be inferred from shock arrival at different steps The z-pinch technique is particularly useful for producing high amplitude shock waves for EOS applications. An alternative approach for using Z is to produce shockless loading directly with the magnetic pressure in the accelerator
Ion-selective steering of the reaction rate and of the catalyst activity by crown-ether complexation
Relationships between Body Measurements, Body Weight, and Productivity in Holstein Dairy Cows
- …