SAPHO syndrome is predominant in middle-age women, characterized by dermatological and osteoarticular manifestations with unknown aetiology. CT scan and bone scintigraphy are useful for diagnosis. There is still no standard treatment to control the disease.

No abstract

In coalescing neutron star (NS) binaries, tidal force can resonantly excite low-frequency ( < ∼ 500 Hz) oscillation modes in the NS, transferring energy between the orbit and the NS. This resonant tide can induce phase shift in the gravitational waveforms, and potentially provide a new window of studying NS interior using gravitational waves. Previous works have considered tidal excitations of pure g-modes (due to stable stratification of the star) and pure inertial modes (due to Coriolis force), with the rotational effect treated in an approximate manner. However, for realistic NSs, the buoyancy and rotational effects can be comparable, giving rise to mixed inertial-gravity modes. We develop a non-perturbative numerical spectral code to compute the frequencies and tidal coupling coefficients of these modes. We then calculate the phase shift in the gravitational waveform due to each resonance during binary inspiral. Given the uncertainties in the NS equation of state and stratification property, we adopt polytropic NS models with a parameterized stratification. We derive relevant scaling relations and survey how the phase shift depends on various properties of the NS. We find that for canonical NSs (with mass M = 1.4M and radius R = 10 km) and modest rotation rates ( < ∼ 300 Hz), the gravitational wave phase shift due to a resonance is generally less than 0.01 radian. But the phase shift is a strong function of R and M , and can reach a radian or more for low-mass NSs with larger radii (R > ∼ 15 km). Significant phase shift can also be produced when the combination of stratification and rotation gives rise to a very low frequency ( < ∼ 20 Hz in the inertial frame) modified g-mode. As a by-product of our precise calculation of oscillation modes in rotating NSs, we find that some inertial modes can be strongly affected by stratification; we also find that the m = 1 r-mode, previously identified to have a small but finite inertial-frame frequency based on the Cowling approximation, in fact has essentially zero frequency, and therefore cannot be excited during the inspiral phase of NS binaries.

We use 2D (axisymmetric) and 3D hydrodynamic simulations to study Bondi-Hoyle-Lyttleton (BHL) accretion with and without transverse upstream gradients. We mainly focus on the regime of high (upstream) Mach number, weak upstream gradients and small accretor size, which is relevant to neutron star (NS) accretion in wind-fed Supergiant X-ray binaries (SgXBs). We present a systematic exploration of the flow in this regime. When there are no upstream gradients, the flow is always stable regardless of accretor size or Mach number. For finite upstream gradients, there are three main types of behavior: stable flow (small upstream gradient), turbulent unstable flow without a disk (intermediate upstream gradient), and turbulent flow with a disk-like structure (relatively large upstream gradient). When the accretion flow is turbulent, the accretion rate decreases non-convergently as the accretor size decreases. The flow is more prone to instability and the disk is less likely to form than previously expected; the parameters of most observed SgXBs place them in the regime of a turbulent, diskless accretion flow. Among the SgXBs with relatively well-determined parameters, we find OAO 1657-415 to be the only one that is likely to host a persistent disk (or disk-like structure); this finding is consistent with observations. c 0000 The Authors arXiv:1907.06108v1 [astro-ph.HE] 13 Jul 2019 R , v Φ ) is evaluated in the rotating frame in which the binary is fixed. D = a b − Rc is the separation between the NS and the surface of the companion (assuming circular orbit). ρ,v are the transverse gradients of density and velocity for single-star wind profile at the NS, and physically correspond to the fractional change of ρ, v per Ra (see text for detailed definition). Ra/R H characterizes the importance of the companion's gravity (with R H being the Hill sphere radius), and Ω b ta characterizes the importance of Coriolis force. The last five parameters show how significantly the system differs from axisymmetric BHL accretion.