The Meladema Laporte, 1835 (Coleoptera, Dytiscidae) of the Sahara Desert

Meladema Laporte, 1835 is a genus of large diving beetles, found in the Western Palaearctic, from the Canary Islands and Madeira to western Turkey (Bilton &amp; Ribera 2017). The genus currently contains four species: the widespread M. coriacea Laporte, 1835, distributed from the Canary Islands to Turkey and ranging from southern France and the central Balkans south to the central Sahara, two Atlantic Island endemics, M. imbricata (Wollaston, 1871) from the western Canary Islands and M. lanio (Fabricius, 1775) from the main island of Madeira, and a fourth, recently described species, M. lepidoptera Bilton &amp; Ribera, 2017 from the Tyrrhenian Islands (Corsica, Sardinia, Elba, Montecristo) and parts of the Italian mainland (Bilton &amp; Ribera 2017). </jats:p

The impact of disturbed galaxy clusters on the kinematics of active galactic nuclei

© 2020 The Author(s) We produce a kinematic analysis of AGN-hosting cluster galaxies from a sample of 33 galaxy clusters selected using the X-ray Clusters Database (BAX) and populated with galaxies from the Sloan Digital Sky Survey Data Release 8. The 33 galaxy clusters are delimited by their relative intensity of member galaxy substructuring as a proxy to core merging to derive two smaller sub-samples of 8 dynamically active (merging) and 25 dynamically relaxed (non-merging) states. The AGN were selected for each cluster sub-sample by employing the WHAN diagram to the strict criteria of log10([N II]/Hα) ≥ −0.32 and EWHα ≥ 6 Å, providing pools of 70 mergings and 225 non-merging AGN sub-populations. By co-adding the clusters to their respective dynamical states to improve the signal-to-noise ratio of our AGN sub-populations we find that merging galaxy clusters on average host kinematically active AGN between 0-1.5r200 as r200 → 0, where their velocity dispersion profile (VDP) presents a significant deviation from the non-AGN sub-population VDP by ≳3σ. This result is indicative that the AGN-hosting cluster galaxies have recently coalesced on to a common potential. Further analysis of the composite distributions illustrates non-merging AGN-hosting sub-populations have, on average, already been accreted and predominantly lie within backsplash regions of the projected phase-space. This suggests merging cluster dynamical states hold relatively younger AGN sub-populations kinematically compared with those found in non-merging cluster dynamical states

Manageable creativity

This article notes a perception in mainstream management theory and practice that creativity has shifted from being disruptive or destructive to 'manageable'. This concept of manageable creativity in business is reflected in a similar rhetoric in cultural policy, especially towards the creative industries. The article argues that the idea of 'manageable creativity' can be traced back to a 'heroic' and a 'structural' model of creativity. It is argued that the 'heroic' model of creativity is being subsumed within a 'structural' model which emphasises the systems and infrastructure around individual creativity rather than focusing on raw talent and pure content. Yet this structured approach carries problems of its own, in particular a tendency to overlook the unpredictability of creative processes, people and products. Ironically, it may be that some confusion in our policies towards creativity is inevitable, reflecting the paradoxes and transitions which characterise the creative process

The rotational profiles of cluster galaxies

© 2019 The Author(s) We compile two samples of cluster galaxies with complimentary hydrodynamic and N-body analysis using FLASH code to ascertain how their differing populations drive their rotational profiles and to better understand their dynamical histories.We select our main cluster sample from the X-ray Galaxy Clusters Database (BAX), which are populated with Sloan Digital Sky Survey (SDSS) galaxies. The BAX clusters are tested for the presence of substructures, acting as proxies for core mergers, culminating in sub-samples of eight merging and 25 non-merging galaxy clusters. An additional sample of 12 galaxy clusters with known dumbbell components is procured using galaxy data from the NASA/IPAC Extragalactic Database (NED) to compare against more extreme environments. BAX clusters of each sample are stacked on to a common RA-Dec. space to produce rotational profiles within the range of 0.0-2.5 r200. Merging stacks possess stronger core rotation at ≲0.5r200 primarily contributed by a red galaxy sub-population from relaxing core mergers; this is alongside high rotational velocities from blue galaxy sub-populations, until they mix and homogenize with the red sub-populations at ∼r200, indicative of an infalling blue galaxy sub-population with interactive mixing between both sub-populations at ≿ r200. FLASH code is utilized to simulate the merger phase between two originally independent clusters and test the evolution of their rotational profiles. Comparisons with the dumbbell clusters leads to the inference that the peculiar core rotations of some dumbbell clusters are the result of the linear motions of core galaxies relaxing on to the potential during post second infall

A new species of Anacaena Thomson, 1859 from South Africa (Coleoptera: Hydrophilidae)

Anacaena namaqua sp. nov. is described from the Northern Cape and Western Cape provinces of South Africa, in an area transitional between the fynbos and succulent karoo biomes. The habitus, aedeagus, femoral pubescence and habitats of the new species are illustrated, together with details of its ecology. A key to all Anacaena confirmed from South Africa to date is also provided. </jats:p

Utilizing Perennial Grass Species’ Population Patterns to Detect Looming Desertification Tipping Points in Semi-Arid Regions

Namibia is one of the global dryland regions facing desertification threats due to overgrazing and recurrent drought. This has disastrous effects on forage provision and consequently on local livelihoods. Unfortunately, the mechanisms underlying sudden shifts of rangeland ecosystems towards a desertified state are still poorly understood. The ability to predict desertification tipping points with the aid of suitable ecological indicators is critical to ensure sustainable management of rangeland resources, which are a backbone of rural livelihood in drylands worldwide. Accordingly, we aimed to identify key perennial grass species that can be used as early-warning indicators for desertification tipping points; and to assess their dynamics and response to grazing pressure. The study was conducted in the eastern region (Otjozondjupa) of Namibia where 4 communal areas and 4 freehold farms (commercial) were selected in order to compare perennial grass population responses within differently management land-use systems. A space-for-time approach was used for this purpose, where plots were laid out along local grazing gradients. Data on species occurrence, size structure and recruitment were collected. Preliminary findings show that a sudden decrease or disappearance of some sensitive native perennial grass species along grazing gradients and lack of seedling recruitment could be a useful hint to an approaching desertification tipping point