We present a statistical analysis of simultaneous optical and X-ray light curves, spanning 600 ks, for 814 pre–main-sequence (PMS) stars in the Orion Nebula Cluster. The aim of this study is to establish the relationship, if any, between the sites of optical and X-ray variability, and thereby to elucidate the origins of X-ray production in PMS stars. In a previous paper we showed that optical a...

Copious x-ray production is shown to attend the collisions of suprathermal (?MeV) protons with ambient electrons,via a process of inverse bremsstrahlung. Such suprathermal protons have been detected in cosmic rays and in solar f lare events; the inverse bremsstrahlung of such cosmic ray protons is expected to make a significant contribution to the diffuse sky background of x-rays and supratherm...

Using Monte Carlo simulations, we demonstrate photopion production from Fermi-accelerated protons and the resulting neutrino production in gamma-ray bursts. Unless internal shocks occur at quite large distance from the center, ultra high-energy protons are depleted by photopion production and synchrotron radiation. Internal shocks at fiducial distance cause neutrino bursts, which accompany gamm...

Salt production and trade is thought to be critical to the development of all states and emergent empires. Until now, however, scientific evidence of early salt production has rarely been presented, and no studies of early Chinese salt production have provided unequivocal proof. Here, we report x-ray fluorescence, x-ray diffraction, and scanning electron microscopy (SEM) analyses that demonstra...

High-resolution X-ray grating spectroscopy enables us to measure the kinematics and spatial distribution of the shock-heated wind plasma in O and early B stars, testing the predictions of the embedded wind shock scenario of massive star Xray production. By fitting models to the resolved, Doppler broadened X-ray emission line profiles measured by the Chandra X-ray Observatory’s grating spectrome...

We present an initial feasibility summary of a femtosecond synchrotron radiation x-ray source based on a flat-beam rf gun and a recirculating superconducting linac that provides beam to an array of undulators and bend magnets. Optical pulse durations of <100 fs are obtained by a combination of electron pulse compression, transverse temporal correlation of the electrons, and x-ray pulse compress...

Sarcomas are relatively resistant because of hypoxia. We previously demonstrated that the transcutaneous CO(2) therapy reduced hypoxic conditions in human malignant fibrous histiocytoma (MFH). Therefore, we hypothesized that transcutaneous CO(2) therapy could enhance the antitumor effect of radiation therapy in human MFH. Our purpose was to evaluate the effects of transcutaneous CO(2) therapy o...

The recent detection of delayed, low energy emission from Gamma-Ray Burst (GRB) sources confirmed the cosmological origin of the bursts and provided support for models where GRBs are produced by the dissipation of the kinetic energy of relativistic fireballs. In this review, ultrahigh-energy, > 10 eV, cosmic-ray and high energy, ∼ 10 eV, neutrino production in GRBs is discussed in the light of ...