Steatocystoma Simplex on the Scalp: A Case Report.

Steatocystoma is a benign adnexal tumor arising from the pilosebaceous duct junction. It can be classified into two groups (steatocystoma simplex and steatocystoma multiplex). Steatocystoma simplex, which presents as a solitary, non-herited very rare lesion in adult. It occurs most commonly in the axillae, in the sternal region and on the arms. Scalp is an extremely rare location. We report a case of 49-years-old male admitted in Department of Surgery, Dhaka Medical College & Hospital, Dhaka, Bangladesh on February 2017 presented with slowly progressing painless, soft, yellowish, single smooth surface mass on the left parietal scalp which had persisted for a period of 8 years. The histopathologic examination revealed a thin-walled cyst consisting of stratified squamous epithelium with lack of granular layer and containing sebaceous gland close to the wall. These findings were consistent with steatocystoma. At the 4-month follow-up, there was no sign of recurrence or development of the steatocystoma or any other masses.

Measurement of the Radiation Energy in the Radio Signal of Extensive Air Showers as a Universal Estimator of Cosmic-Ray Energy.

We measure the energy emitted by extensive air showers in the form of radio emission in the frequency range from 30 to 80 MHz. Exploiting the accurate energy scale of the Pierre Auger Observatory, we obtain a radiation energy of 15.8±0.7(stat)±6.7(syst) MeV for cosmic rays with an energy of 1 EeV arriving perpendicularly to a geomagnetic field of 0.24 G, scaling quadratically with the cosmic-ray energy. A comparison with predictions from state-of-the-art first-principles calculations shows agreement with our measurement. The radiation energy provides direct access to the calorimetric energy in the electromagnetic cascade of extensive air showers. Comparison with our result thus allows the direct calibration of any cosmic-ray radio detector against the well-established energy scale of the Pierre Auger Observatory.

Search for patterns by combining cosmic-ray energy and arrival directions at the Pierre Auger Observatory.

Energy-dependent patterns in the arrival directions of cosmic rays are searched for using data of the Pierre Auger Observatory. We investigate local regions around the highest-energy cosmic rays with [Formula: see text] eV by analyzing cosmic rays with energies above [Formula: see text] eV arriving within an angular separation of approximately 15[Formula: see text]. We characterize the energy distributions inside these regions by two independent methods, one searching for angular dependence of energy-energy correlations and one searching for collimation of energy along the local system of principal axes of the energy distribution. No significant patterns are found with this analysis. The comparison of these measurements with astrophysical scenarios can therefore be used to obtain constraints on related model parameters such as strength of cosmic-ray deflection and density of point sources.