998 research outputs found
A Combined Radio Multi-Survey Catalog of Fermi Unassociated Sources
Approximately one-third of existing -ray sources identified by the
are considered to be unassociated,
with no known counterpart at other frequencies/wavelengths. These sources have
been the subject of intense scrutiny and observational effort during the
observatory's mission lifetime, and here we present a method of leveraging
existing radio catalogs to examine these sources without the need for specific
dedicated observations, which can be costly and complex. Via the inclusion of
many sensitive low-frequency catalogs we specifically target steep spectrum
sources such as pulsars. This work has found steep-spectrum radio sources
contained inside 591 unassociated fields, with at least 21 of
them being notable for having pulsar-like -ray properties as well. We
also identify a number of other fields of interest based on various radio and
-ray selections.Comment: 13 pages, 5 figures, 3 tables, accepted for publication in Ap
More Discriminants with the Brezing-Weng Method
The Brezing-Weng method is a general framework to generate families of
pairing-friendly elliptic curves. Here, we introduce an improvement which can
be used to generate more curves with larger discriminants. Apart from the
number of curves this yields, it provides an easy way to avoid endomorphism
rings with small class number
Initial maternal meiotic I error leading to the formation of a maternal i(2q) and a paternal i(2p) in a healthy male
We report on the investigation of the parental origin and mode of formation of the two isochromosomes, i(2p) and i(2q), detected in a healthy adult male. Conventional cytogenetic analysis revealed the proband’s lack of structurally normal chromosomes 2, these being replaced by an i(2p) and an i(2q). Investigation of the parental origin of the isochromosomes revealed a paternal origin of the i(2p) chromosome and a maternal origin of the i(2q) chromosome. Thus, the formation of both isochromosomes, or at least of the paternal i(2p), appears to have occurred postzygotically. Interestingly, whilst a paternal isodisomy was observed for the entire 2p, maternal heterodisomy was detected for two segments of 2q, separated by a segment showing isodisomy. The results are indicative of an initial error (non-disjunction or i(2q) formation) concerning the maternal chromosomes 2 during meiosis I, which likely favored the subsequent mitotic recombination event resulting in the presence of two isochromosomes. To the best of our knowledge this is the first case of an initial meiotic error, followed by postzygotic trisomy rescue through the formation of isochromosomes, resulting in a normal phenotype. A prenatal detection, by cytogenetic and molecular analysis, of such chromosome abnormality would have led to the incorrect conclusion of a most likely poor prognosis for the fetus
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