Morphometric Analysis of Gerbillus Andersoni, G. Campestris and G. Amoenus From Egypt

Abstract

Despite a significant number of studies on the taxonomy of small mammals, very little of this work has been conducted on species in Egypt. External, cranial and dental morphometric analysis of the closely related Gerbillus andersoni, G. campestris and G. amoenus from different ecogeographical regions of Egypt were studied. Statistical analyses of cranial and dental variability allowed us to discriminate three morphological groups which are congruent with the three clusters suggested by previous morphological studies. Higher similarity is observed between G. andersoni populations in the Sinai and Western Mediterranean Coastal Desert despite the fact that they are separated from each other by about 200 km of the Nile Delta. Cluster and principal component analysis, show higher degree of divergence between the subgenus Dipodillus and the other two subgenera Gerbillus and Hendecapleura. This fact suggests that the morphometric differences observed among species within the genus Gerbillus are not mainly related to its phylogeny.

Neutron Star Phase Transition as the Origin for the Fast Radio Bursts and Soft Gamma-Ray Repeaters of SGR J1935 + 2154

“…Very recently, SGR J1935 + 2154 has been reported with two giant glitches, with the magnitude Younes et al 2022). Similar to the giant glitches in radio pulsars, they are likely originated from the superfluid mechanism (Alpar et al 1996;Haskell & Melatos 2015;Wang et al 2021).…”

AstroSat observation of the magnetar SGR J1830−0645 during its first detected X-ray outburst

“…This source exhibited coherent pulsation at a frequency of ∼ 0.096 Hz. The spin period was later confirmed by Ray et al (2020) and Younes et al (2020) from observations made with the 0.2-12 keV X-ray telescope onboard the Neutron Star Interior Composition Explorer (NICER). Using the phase-coherent technique, Coti Zelati et al (2021) determined a spin-down rate of -6.2×10 −14 Hz s −1 by using data from Swift, XMM-Newton and NuSTAR.…”

A Note on the Anti-glitch of Magnetar SGR 1935+2154

“…The magnetar SGR 1935+2154 is reported to have an antiglitch (i.e., spin-down event) (Younes et al 2022). The antiglitch is also followed by fast radio bursts and pulsed radio emission (Younes et al 2022;Good & CHIME/FRB Collaboration 2020;Zhu et al 2020). This will make SGR 1935+2154 the sixth magnetar to show pulsed radio emission (Camilo et al 2006;Huang et al 2021).…”