High speed photometry of faint Cataclysmic Variables - VII. Targets selected from the Sloan Digital Sky Survey and the Catalina Real-time Transient Survey

We present high speed photometric observations of 20 faint cataclysmic variables, selected from the Sloan Digital Sky Survey and Catalina catalogues. Measurements are given of 15 new directly measured orbital periods, including four eclipsing dwarf novae (SDSS0904+03, CSS0826-00, CSS1404-10 and CSS1626-12), two new polars (CSS0810+00 and CSS1503-22) and two dwarf novae with superhumps in quiescence (CSS0322+02 and CSS0826-00). Whilst most of the dwarf novae presented here have periods below 2 h, SDSS0805+07 and SSS0617-36 have relatively long orbital periods of 5.489 and 3.440 h, respectively. The double humped orbital modulations observed in SSS0221-26, CSS0345-01, CSS1300+11 and CSS1443-17 are typical of low mass transfer rate dwarf novae. The white dwarf primary of SDSS0919+08 is confirmed to have non-radial oscillations and quasi-periodic oscillations were observed in the short-period dwarf nova CSS1028-08 during outburst. We further report the detection of a new nova-like variable (SDSS1519+06). The frequency distribution of orbital periods of CVs in the Catalina survey has a high peak near ~80 min orbital period, independently confirming that found by Gaensicke et al (2009) from SDSS sources. We also observe a marked correlation between the median in the orbital period distribution and the outburst class, in the sense that dwarf novae with a single observed outburst (over the 5-year baseline of the CRTS coverage) occur predominantly at shortest orbital period.Comment: 17 pages, 38 figures, accepted for publication in MNRA

Delineating Functional Corridors Linking Leopard Habitat in the Eastern and Western Cape, South Africa

Natural landscapes are increasingly fragmented due to human activity. This contributes to isolation and inadequate gene flow among wildlife populations. These threats intensify where populations are already low, and gene flow is compromised. Ensuring habitat connectivity despite transformed landscapes can mitigate these risks. Leopards are associated with high levels of biodiversity and are the last widely occurring, free-roaming apex predator in South Africa. Although highly adaptable, leopard survival is reduced by human-caused mortality and habitat destruction. We aimed to assess the connectivity of leopard habitat in the Eastern Cape and Western Cape, South Africa. We predicted leopard habitat by correlating GPS data from 31 leopards to environmental features that included human-associated and natural landscapes. We used circuit theory to delineate corridors linking known leopard populations. Finally, using camera traps, we tested whether five predicted corridors were used by leopards. Leopard habitat was strongly correlated to moderate slopes and areas of natural land-cover and plantations, highlighting mountainous areas as important habitat with high connectivity probability. While most habitat patches showed some level of connectivity, leopards avoided highly transformed landscapes, potentially isolating some populations. Where corridors are not functional, active conservation measures for species connectivity becomes important

High-speed photometry of faint cataclysmic variables – viii. Targets from the catalina real-time transient survey

Contains fulltext : 122791.pdf (preprint version ) (Open Access