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Pulsars in binary systems with strong companion winds can have the magnetopause separating their magnetosphere from the wind located well within their light cylinder. This bow-like enclosure effectively creates a waveguide that confines the pulsar’s electromagnetic fields and can significantly alter its spindown. In this paper, we study the spindown of compressed pulsar magnetospheres in such systems. We parameterize the confinement as the ratio between the equatorial position of the magnetopause (or standoff distance) R _m and the pulsar’s light cylinder R _LC . Using particle-in-cell simulations, we quantify the pulsar spindown for a range of compressions, R _m / R _LC = 1/3–1, and inclination angles, χ = 0°…90°, between magnetic and rotation axes. Our strongly confined models ( R _m / R _LC = 1/3) show two distinct limits. For χ = 0°, the spindown of a compressed pulsar magnetosphere is enhanced by approximately a factor of three compared to an isolated pulsar due to the increased number of open magnetic field lines. Conversely, for χ = 90°, the compressed pulsar spins down at less than 40% of the rate of an isolated reference pulsar due to the mismatch between the pulsar wind stripe wavelength and the waveguide size. We apply our analysis to the 2.77 s oblique rotator ( χ = 60°) in the double-pulsar system PSR J0737-3039. With the numerically derived spindown estimate, we constrain its surface magnetic field to B _* ≈ (7.3 ± 0.2) × 10 ^11 G. We discuss the time modulation of its period derivative, the effects of compression on its braking index, and implications for the radio eclipse in PSR J0737-3039.

Rheumatoid arthritis (RA) is a common inflammatory disease with several implications on health, disability and economy. Conventional treatment for RA centers on anti-inflammatory drugs and specific targeting of tumor necrosis factor  (TNF-) and interleukin 6 (IL-6). Baricitinib is a novel, Food and Drug Administration (FDA) approved, once daily oral drug that is effective in combination with current treatment and results in significantly reduced symptoms with good safety profile. Further studies are required to find rare side effects and evaluate the long term efficacy in disease modulation and patient symptom reduction. This is a comprehensive review of the literature on baricitinib for the treatment of RA. This review provides an update on the pathophysiology, diagnosis and conventional treatment of RA, then proceeds to introduce baricitinib and the data that exists to support or refute its use in RA. The presented study also indicated clinical trials confirming the effectiveness of baricitinib in this indication.

Some of the most energetic pulsars exhibit rotation-modulated γ -ray emission in the 0.1–100 GeV band. The luminosity of this emission is typically 0.1%–10% of the pulsar spin-down power ( γ -ray efficiency), implying that a significant fraction of the available electromagnetic energy is dissipated in the magnetosphere and reradiated as high-energy photons. To investigate this phenomenon we model a pulsar magnetosphere using 3D particle-in-cell simulations with strong synchrotron cooling. We particularly focus on the dynamics of the equatorial current sheet where magnetic reconnection and energy dissipation take place. Our simulations demonstrate that a fraction of the spin-down power dissipated in the magnetospheric current sheet is controlled by the rate of magnetic reconnection at microphysical plasma scales and only depends on the pulsar inclination angle. We demonstrate that the maximum energy and the distribution function of accelerated pairs is controlled by the available magnetic energy per particle near the current sheet, the magnetization parameter. The shape and the extent of the plasma distribution is imprinted in the observed synchrotron emission, in particular, in the peak and the cutoff of the observed spectrum. We study how the strength of synchrotron cooling affects the observed variety of spectral shapes. Our conclusions naturally explain why pulsars with higher spin-down power have wider spectral shapes and, as a result, lower γ -ray efficiency.

We present the results of 3D particle-in-cell simulations that explore relativistic magnetic reconnection in pair plasma with strong synchrotron cooling and a small mass fraction of nonradiating ions. Our results demonstrate that the structure of the current sheet is highly sensitive to the dynamic efficiency of radiative cooling. Specifically, stronger cooling leads to more significant compression of the plasma and magnetic field within the plasmoids. We demonstrate that ions can be efficiently accelerated to energies exceeding the plasma magnetization parameter, ≫ σ , and form a hard power-law energy distribution, f _i ∝ γ ^−1 . This conclusion implies a highly efficient proton acceleration in the magnetospheres of young pulsars. Conversely, the energies of pairs are limited to either σ in the strong cooling regime or the radiation burnoff limit, γ _syn , when cooling is weak. We find that the high-energy radiation from pairs above the synchrotron burnoff limit, ε _c ≈ 16 MeV, is only efficiently produced in the strong cooling regime, γ _syn < σ . In this regime, we find that the spectral cutoff scales as ε _cut ≈ ε _c ( σ / γ _syn ) and the highest energy photons are beamed along the direction of the upstream magnetic field, consistent with the phenomenological models of gamma-ray emission from young pulsars. Furthermore, our results place constraints on the reconnection-driven models of gamma-ray flares in the Crab Nebula.

It is currently thought that visual pigments in vertebrate photoreceptors are regenerated exclusively through enzymatic cycles. Here the authors show that mammalian photoreceptors also regenerate opsin pigments in light through photoisomerization of N-ret-PE (N-retinylidene-phosphatidylethanolamine.