Let R denote a commutative noetherian ring, and o an ideal of R. Elements x j , . . . , x n e R are called independent with respect to a, or simply a-independent, if every form Fe R[Xlf..., X^\ such that F(xl 5. . . , xn) = 0 has all its coefficients in a. Valla [10] introduced the notation sup a for the maximal number of a-independent elements in a. He found that sup a is bounded above by the ...

We present the first direct measurements of the rest-frame 10–40 keV X-ray luminosity function (XLF) of Active Galactic Nuclei (AGNs) based on a sample of 94 sources at 0.1 < z < 3, selected at 8–24 keV energies from sources in the NuSTAR extragalactic survey program. Our results are consistent with the strong evolution of the AGN population seen in prior, lower-energy studies of the XLF. Howev...

2 Abstract We report the results of the Chandra ACIS sub-arcsecond resolution X-ray observation of the archetypal merger radio galaxy NGC 1316 (Fornax A). We confirm the presence of fine sub-structures in the hot Interstellar Medium (ISM). Some of these are likely to result from interaction with the radio jets, while others may be related to a complex intermingling of different phases of the IS...

A detailed discussion of the X-ray luminosity functions of pre-main sequence and young main-sequence objects in the Taurus-AurigaPerseus region based on the ROSAT archive is presented. One of the main conclusions is that the XLF of classical and weak-line T Tauri stars (TTS) are different: weak-line TTS are X-ray brighter than classical TTS. Various possible biases related to the sample selecti...

We present the results and parameterization of the 0.5-2 keV Luminosity Function of AGNs from various ROSAT Surveys, ranging from the ROSAT bright Survey from the ROSAT All-Sky Survey (RASS) to the Ultra-Deep survey on the Lockman hole. A Luminositydependent density evolution model, where the density evolution rate drops at low luminosities, gives an excellent parametric description of the over...

Chromosomal double stranded breaks (DSBs) are regarded as the most cytotoxic form of DNA damage, and occur as a result of normal cellular processes, such as DNA replication, as well as in response to ionizing radiation, and chemotherapeutics. These breaks must be repaired to ensure genomic stability and viability. In vertebrates, nonhomologous end joining (NHEJ) is the main pathway for repair o...