157 research outputs found
The new a-theory of time
The New A-theory of Time (TNAT) is the view, to be elaborated and defended in this article, that many times exist, and that time is real in virtue of every moment in time bearing each of the so-called A-properties: past, present and future. I argue that TNAT is at least as theoretically virtuous as mainstream views in the philosophy of time and may have some claim to being our best theory of time. I show that the properties âpastâ, âpresentâ and âfutureâ can be understood as compatible intrinsic properties. Having demonstrated that this account of the A-properties is coherent, I go on to demonstrate how TNAT can give us an account of passage, change and the truth-conditions for temporal sentences. In the final section of the article, I develop a tentative argument in favour of TNAT, though concede that we have to settle for the result that TNAT is on a par with our other theories of time. In the remainder of this opening section, my aim is to situate the current proposal as a direct response to McTaggartâs infamous argument against the reality of time
Observation of 46Cr and testing and isobaric multiplet mass equation at high spin
An experimental study was carried out to observe excited states in 46Cr using the 12C(36Ar,2n) reaction with GAMMASPHERE and the FMA. The yrast band in 46Cr and the T=1 states in 46V were established up to (tentatively) 12+, the highest spin T=1 triplet unknown. The results were used to test f p-shell model calculations
Tensor polarization in elastic electron-deuteron scattering in the momentum transfer range 3.8â€Qâ€4.6 fm-1
The tensor polarization of the recoil deuteron in elastic electron-deuteron scattering has been measured at the Bates Linear Accelerator Center at three values of four-momentum transfer Q=3.78, 4.22, and 4.62 fm-1, corresponding to incident electron energies of 653, 755, and 853 MeV. The scattered electrons and the recoil deuterons were detected in coincidence. The recoil deuterons were transported to a liquid hydrogen target to undergo a second scattering. The angular distribution of the dâ-p scattering was measured using a polarimeter. The polarimeter was calibrated in an auxiliary experiment using a polarized deuteron beam at the Laboratoire National Saturne. A Monte Carlo procedure was used to generate interpolated calibration data because the energy spread in the deuteron energies in the Bates experiment spanned the range of deuteron energies in the calibration experiment. The extracted values of t20 are compared to predictions of different theoretical models of the electromagnetic form factors of the deuteron: nonrelativistic and relativistic nucleon-meson dynamics, Skyrme model, quark models, and perturbative quantum chromodynamics. Along with the world data the structure functions A(Q) and B(Q) are used to separate the charge monopole and charge quadrupole form factors of the deuteron. A node in the charge monopole form factor is observed at Q=4.39±0.16 fm-1
Measurement of tensor polarization in elastic electron-deuteron scattering in the momentum-transfer range 3.8â€qâ€4.6 fm-1
The tensor polarization t20 of the recoil deuteron in elastic e-d scattering has been measured for three values of four-momentum transfer, q=3.78, 4.22, and 4.62 fm-1. The data have been used to locate the first node in the charge monopole form factor of the deuteron at q=4.39±0.16 fm-1. The results for t20 are in reasonable agreement with expectations based on the nucleon-meson description of nuclear dynamic
Guidelines for the management of pregnancy in women with cystic fibrosis
Women with cystic fibrosis (CF) now regularly survive into their reproductive years in good health and wish to have a baby. Many pregnancies have been reported in the literature and it is clear that whilst the outcome for the baby is generally good and some mothers do very well, others find either their CF complicates the pregnancy or is adversely affected by the pregnancy. For some, pregnancy may only become possible after transplantation. Optimal treatment of all aspects of CF needs to be maintained from the preconceptual period until after the baby is born. Clinicians must be prepared to modify their treatment to accommodate the changing physiology during pregnancy and to be aware of changing prescribing before conception, during pregnancy, after birth and during breast feeding. This supplement offers consensus guidelines based on review of the literature and experience of paediatricians, adult and transplant physicians, and nurses, physiotherapists, dietitians, pharmacists and psychologists experienced in CF and anaesthetist and obstetricians with experience of CF pregnancy. It is hoped they will provide practical guidelines helpful to the multidisciplinary CF teams caring for pregnant women with CF
Palaeolimnological evidence for recent climatic change in lakes from the northern Urals, arctic Russia
Search for gravitational-wave transients associated with magnetar bursts in advanced LIGO and advanced Virgo data from the third observing run
Gravitational waves are expected to be produced from neutron star oscillations associated with magnetar giant f lares and short bursts. We present the results of a search for short-duration (milliseconds to seconds) and longduration (âŒ100 s) transient gravitational waves from 13 magnetar short bursts observed during Advanced LIGO, Advanced Virgo, and KAGRAâs third observation run. These 13 bursts come from two magnetars, SGR1935 +2154 and SwiftJ1818.0â1607. We also include three other electromagnetic burst events detected by FermiGBM which were identified as likely coming from one or more magnetars, but they have no association with a known magnetar. No magnetar giant flares were detected during the analysis period. We find no evidence of gravitational waves associated with any of these 16 bursts. We place upper limits on the rms of the integrated incident gravitational-wave strain that reach 3.6 Ă 10âÂČÂł Hz at 100 Hz for the short-duration search and 1.1 Ă10âÂČÂČ Hz at 450 Hz for the long-duration search. For a ringdown signal at 1590 Hz targeted by the short-duration search the limit is set to 2.3 Ă 10âÂČÂČ Hz. Using the estimated distance to each magnetar, we derive upper limits upper limits on the emitted gravitational-wave energy of 1.5 Ă 1044 erg (1.0 Ă 1044 erg) for SGR 1935+2154 and 9.4 Ă 10^43 erg (1.3 Ă 1044 erg) for Swift J1818.0â1607, for the short-duration (long-duration) search. Assuming isotropic emission of electromagnetic radiation of the burst ïŹuences, we constrain the ratio of gravitational-wave energy to electromagnetic energy for bursts from SGR 1935+2154 with the available ïŹuence information. The lowest of these ratios is 4.5 Ă 103
A joint Fermi-GBM and Swift-BAT analysis of gravitational-wave candidates from the third gravitational-wave observing run
We present Fermi Gamma-ray Burst Monitor (Fermi-GBM) and Swift Burst Alert Telescope (Swift-BAT) searches for gamma-ray/X-ray counterparts to gravitational-wave (GW) candidate events identified during the third observing run of the Advanced LIGO and Advanced Virgo detectors. Using Fermi-GBM onboard triggers and subthreshold gamma-ray burst (GRB) candidates found in the Fermi-GBM ground analyses, the Targeted Search and the Untargeted Search, we investigate whether there are any coincident GRBs associated with the GWs. We also search the Swift-BAT rate data around the GW times to determine whether a GRB counterpart is present. No counterparts are found. Using both the Fermi-GBM Targeted Search and the Swift-BAT search, we calculate flux upper limits and present joint upper limits on the gamma-ray luminosity of each GW. Given these limits, we constrain theoretical models for the emission of gamma rays from binary black hole mergers
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