[en] Short communication

[en] The mechanism for the production of 1) e⁺e^- pairs, 2) e⁺e^- pairs associated with γ rays and 3) the γ - γ events are given

[en] Objective. To compare disease activity in patients of established Rheumatoid Arthritis estimated by Disease Activity Score-28 (DAS-28) C-reactive protein (CRP) and Disease Activity Score-28 Erythrocyte Sedimentation Rate (ESR). Material and Methods: This cross-sectional comparative study was conducted at Department of Rheumatology, Pak Emirates Military Hospital Rawalpindi, May 2022 to Oct 2022. Using consecutive non probability sampling, patients of Rheumatoid Arthritis (RA) of 30 to 65 years age of either gender were selected who had the disease for at least 1 year, never received biologics Disease modifying anti-rheumatic drugs (DMARDs) or immunosuppressive therapy and no signs of active infective etiology. DAS28 score was calculated using ESR and CRP to assess disease severity. Sensitivity, specificity, and agreement comparison was done between DAS28-ESR and DAS28-CRP and κ -coefficient was calculated with discordance proportion. Results. Out of 70 patients, 50 (70%) were female and 20 (28%) were male with mean age of included patients 49.9 ± 7.5 years. Mean disease activity score, calculated using ESR was 4.1 ± 1.25 SD was higher than mean DAS28 score of 3.5 ± 1.12 SD with CRP. Twenty (28.6%) patients had High Disease Activity (HDA) (DAS28 > 5.1) when assessed by DAS28-ESR score as compared to 8 (11.4%) patients by DAS28-CRP score with 17.1% discordance and κ Coefficient of 0.402 corresponding to minimal agreement amid DAS28-ESR and DAS28-CRP for HDA (p < 0.005). DAS28 score using ESR as evaluating tool had 35% sensitivity and 98% specificity of detecting RA patients with High Disease Activity. Conclusion. DAS28-ESR was preferable as compared to DAS28-CRP for monitoring disease activity and treatment decision. (author)

[en] This paper presents a review of the organic solid-state polymer materials, which have become established as a new laser media. The photostability of these materials is discussed. Different types of solid-state lasers built around these materials are also reviewed

[en] Short communication. 3 refs., 3 figs

[en] Short communication. 6 refs., 1 tab

[en] Short communication. 5 refs., 1 tab

[en] Short communication. 3 refs

[en] Eruptive activity in the solar corona can often lead to the propagation of shockwaves. In the radio domain the primary signature of such shocks are type II radio bursts, observed in dynamic spectra as bands of emission slowly drifting towards lower frequencies over time. These radio bursts can sometimes have inhomogeneous and fragmented fine structure, but the cause of this fine structure is currently unclear. Here we observe several type II radio bursts on 2019-March-20th using the New Extension in Nancay Upgrading LOFAR (NenuFAR), a radio interferometer observing between 10-85 MHz. We show that the distribution of size-scales of density perturbations associated with the fine structure of one type II follows a power law with a spectral index of -1.71, which closely matches the value of -5/3 expected of fully developed turbulence. We determine this turbulence to be upstream of the shock, in background coronal plasma at a heliocentric distance of ~2 Rsun. The observed inertial size-scales of the turbulent density inhomogeneities range from ~62 Mm to ~209 km. This shows that type II fine structure and fragmentation can be due to shock propagation through an inhomogeneous and turbulent coronal plasma, and we discuss the implications of this on electron acceleration in the coronal shock.

[en] We report low-frequency observations of quasi-periodic, circularly polarized, harmonic type III radio bursts whose associated sunspot active regions were located close to the solar limb. The measured periodicity of the bursts at 80 MHz was ≈5.2 s, and their average degree of circular polarization (dcp) was ≈0.12. We calculated the associated magnetic field B (1) using the empirical relationship between the dcp and B for the harmonic type III emission, and (2) from the observed quasi-periodicity of the bursts. Both the methods result in B ≈ 4.2 G at the location of the 80 MHz plasma level (radial distance r ≈ 1.3 R_☉) in the active region corona