Cross-Scale Energy Transfer from Fluid-Scale Alfvén Waves to Kinetic-Scale Ion Acoustic Waves in the Earth's Magnetopause Boundary Layer.

In space plasmas, large-amplitude Alfvén waves can drive compressive perturbations, accelerate ion beams, and lead to plasma heating and the excitation of ion acoustic waves at kinetic scales. This energy channeling from fluid to kinetic scales represents a complementary path to the classical turbulent cascade. Here, we present observational and computational evidence to validate this hypothesis by simultaneously resolving the fluid-scale Alfvén waves, kinetic-scale ion acoustic waves, and their imprints on ion velocity distributions in the Earth's magnetopause boundary layer.

Spacecraft Observations and Theoretical Understanding of Slow Electron Holes.

We present Magnetospheric Multiscale observations showing large numbers of slow electron holes with speeds clustered near the local minimum of double-humped velocity distribution functions of background ions. Theoretical computations show that slow electron holes can avoid the acceleration that otherwise prevents their remaining slow only under these same circumstances. Although the origin of the slow electron holes is still elusive, the agreement between observation and theory about the conditions for their existence is remarkable.

Direct Observation of Electron Distributions inside Millisecond Duration Electron Holes.

Despite the importance of millisecond duration spatial structures [chorus wave nonlinearity or time domain structures (TDS)] to plasma dynamics, there have been no direct observations of the generation and interaction of these waves and TDS with electrons at the millisecond timescale required for their understanding. Through superposition of 0.195 ms Magnetospheric Multiscale Satellite electron measurements inside 37 superposed, millisecond duration electron holes, the first observations of electron spectra and pitch angle distributions on a submillisecond timescale have been obtained.

Tuberculous peritonitis in children: Two case reports highlighting the important role of imaging.

Tuberculous peritonitis is an uncommon extrapulmonary form of infection, frequently presenting with nonspecific and insidious symptoms. Diagnosis is therefore difficult, unsuspected, and often delayed, especially in the pediatric patient without an obvious history of exposure to the pathogen. This report presents a 9-year-old Hispanic girl and a 3-year-old African American boy presenting with nonspecific and insidious symptoms, such as abdominal pain, distention, and fever in whom computed tomography findings of peritoneal thickening and enhancement, high density ascites, lymphadenopathy, and bowel wall thickening acted as key components in establishing a final diagnosis of the condition.