20 research outputs found
Observation of inverse Compton emission from a long γ-ray burst.
Long-duration γ-ray bursts (GRBs) originate from ultra-relativistic jets launched from the collapsing cores of dying massive stars. They are characterized by an initial phase of bright and highly variable radiation in the kiloelectronvolt-to-megaelectronvolt band, which is probably produced within the jet and lasts from milliseconds to minutes, known as the prompt emission1,2. Subsequently, the interaction of the jet with the surrounding medium generates shock waves that are responsible for the afterglow emission, which lasts from days to months and occurs over a broad energy range from the radio to the gigaelectronvolt bands1-6. The afterglow emission is generally well explained as synchrotron radiation emitted by electrons accelerated by the external shock7-9. Recently, intense long-lasting emission between 0.2 and 1 teraelectronvolts was observed from GRB 190114C10,11. Here we report multi-frequency observations of GRB 190114C, and study the evolution in time of the GRB emission across 17 orders of magnitude in energy, from 5 × 10-6 to 1012 electronvolts. We find that the broadband spectral energy distribution is double-peaked, with the teraelectronvolt emission constituting a distinct spectral component with power comparable to the synchrotron component. This component is associated with the afterglow and is satisfactorily explained by inverse Compton up-scattering of synchrotron photons by high-energy electrons. We find that the conditions required to account for the observed teraelectronvolt component are typical for GRBs, supporting the possibility that inverse Compton emission is commonly produced in GRBs
Arthroscopic-Assisted Lateral Extra-Articular Tenodesis With Knotless Anchor Fixation
Recent studies have reported the biomechanical and clinical advantages of lateral extraarticular augmentation procedures including the modified lateral extra-articular tenodesis (LET) in the setting of anterior cruciate ligament reconstruction. LET has been shown to significantly decrease re-rupture rates in high-risk patients and decrease anterior cruciate ligament graft forces during pivoting loads and instrumented anterior laxity testing. Many variations of the modified LET approaches have been described. However, concerns including lateral hematoma, wound-healing complications, and increased operative time exist. This minimally invasive, arthroscopic-assisted approach using a knotless, all-suture anchor allows for direct visualization through a 2-cm incision and inherently decreases the morbidity associated with traditional LET techniques
From distal to proximal: routine educational data monitoring in school-based mental health
Hypothalamic-pituitary-adrenal axis dysfunction as a neurobiological correlate of emotion dysregulation in adolescent suicide
Regional variation in characteristics of patients with decompensated cirrhosis admitted to hospitals in the UK
Geometric representation of association between categories
Categorical data, simplex, triangular plot, paired comparisons, rank orders, permutation polytope, center of gravity, BTL model, Rasch model, inertia, association model, variation, multidimensional unfolding, biplot, multinomial response model, loglinear model, forced classification, classification tree,