Photoionized plasma calculations using laboratory and astrophysical models

We present numerical simulations from the code GALAXY, frequently employed to model the distribution of excitation and ionization, and the spectral emission from laboratory plasma experiments. In particular, preliminary calculations relevant to the Lawrence Livermore National Laboratory photoionization collaboration are presented, along with results which compare GALAXY with results from the astrophysical code CLOUDY

Tarantulas (Araneae : Theraphosidae) in the pet trade in South Africa

CITATION: Shivambu, T.C. et al. 2020. Tarantulas (Araneae: Theraphosidae) in the pet trade in South Africa. African Zoology 55(4):323-336. doi:10.1080/15627020.2020.1823879The original publication is available at https://www.tandfonline.com/toc/tafz20/currentMany alien species have been introduced around the world as part of the pet trade, and some have escaped captivity and become invasive. In South Africa, many species of tarantula (Theraphosidae) are kept as pets. It is not known which species are traded, which are most popular, and whether their names are correctly applied. Online traders and physical pet stores were investigated between 2015 and 2016 to determine the extent or size of trade, species composition, most popular species, and their invasion history elsewhere. In total, 36 specimens, three individuals from 12 putative species, were also purchased for DNA barcoding targeting the COI gene region to quantify the accuracy of tarantula identification by traders. In total, 195 tarantula species were advertised for sale, and the most popular species were Brachypelma albopilosum Valerio, 1980 (n = 199), B. vagans Ausserer, 1875 (n = 132), and Grammostola rosea Walckenaer, 1837 (n = 120). The composition of shared species differed between the sources and most of the species were advertised online. Only one of the popular species, B. vagans, has been recorded as being invasive elsewhere. Only 36% of the barcoded specimens matched existing barcodes in online repositories that had the same species name. The three individuals from 12 putative species were not in the same terminal clade as those of conspecifics in the Barcode of Life Data System (BOLD) and the NCBI GenBank reference sequences. A large proportion of the known tarantula species are traded in South Africa and must be included in management and risk assessments to avoid potential invasions

The role of positive selection in determining the molecular cause of species differences in disease

Related species, such as humans and chimpanzees, often experience the same disease with varying degrees of pathology, as seen in the cases of Alzheimer's disease, or differing symptomatology as in AIDS. Furthermore, certain diseases such as schizophrenia, epithelial cancers and autoimmune disorders are far more frequent in humans than in other species for reasons not associated with lifestyle. Genes that have undergone positive selection during species evolution are indicative of functional adaptations that drive species differences. Thus we investigate whether biomedical disease differences between species can be attributed to positively selected genes

Thermoregulatory traits combine with range shifts to alter the future of montane ant assemblages.

Predicting and understanding the biological response to future climate change is a pressing challenge for humanity. In the 21st century, many species will move into higher latitudes and higher elevations as the climate warms. In addition, the relative abundances of species within local assemblages is likely to change. Both effects have implications for how ecosystems function. Few biodiversity forecasts, however, take account of both shifting ranges and changing abundances. We provide a novel analysis predicting the potential changes to assemblage level relative abundances in the 21st century. We use an established relationship linking ant abundance and their colour and size traits to temperature and UV-B to predict future abundance changes. We also predict future temperature driven range shifts and use these to alter the available species pool for our trait-mediated abundance predictions. We do this across three continents under a low greenhouse gas emissions scenario (RCP2.6) and a business-as-usual scenario (RCP8.5). Under RCP2.6, predicted changes to ant assemblages by 2100 are moderate. On average, species richness will increase by 26%, while species composition and relative abundance structure will be 26% and 30% different, respectively, compared with modern assemblages. Under RCP8.5, however, highland assemblages face almost a tripling of species richness and compositional and relative abundance changes of 66% and 77%. Critically, we predict that future assemblages could be reorganised in terms of which species are common and which are rare: future highland assemblages will not simply comprise upslope shifts of modern lowland assemblages. These forecasts reveal the potential for radical change to montane ant assemblages by the end of the 21st century if temperature increases continue. Our results highlight the importance of incorporating trait-environment relationships into future biodiversity predictions. Looking forward, the major challenge is to understand how ecosystem processes will respond to compositional and relative abundance changes. This article is protected by copyright. All rights reserved

Thermoregulatory traits combine with range shifts to alter the future of montane ant assemblages.

Predicting and understanding the biological response to future climate change is a pressing challenge for humanity. In the 21st century, many species will move into higher latitudes and higher elevations as the climate warms. In addition, the relative abundances of species within local assemblages is likely to change. Both effects have implications for how ecosystems function. Few biodiversity forecasts, however, take account of both shifting ranges and changing abundances. We provide a novel analysis predicting the potential changes to assemblage level relative abundances in the 21st century. We use an established relationship linking ant abundance and their colour and size traits to temperature and UV-B to predict future abundance changes. We also predict future temperature driven range shifts and use these to alter the available species pool for our trait-mediated abundance predictions. We do this across three continents under a low greenhouse gas emissions scenario (RCP2.6) and a business-as-usual scenario (RCP8.5). Under RCP2.6, predicted changes to ant assemblages by 2100 are moderate. On average, species richness will increase by 26%, while species composition and relative abundance structure will be 26% and 30% different, respectively, compared with modern assemblages. Under RCP8.5, however, highland assemblages face almost a tripling of species richness and compositional and relative abundance changes of 66% and 77%. Critically, we predict that future assemblages could be reorganised in terms of which species are common and which are rare: future highland assemblages will not simply comprise upslope shifts of modern lowland assemblages. These forecasts reveal the potential for radical change to montane ant assemblages by the end of the 21st century if temperature increases continue. Our results highlight the importance of incorporating trait-environment relationships into future biodiversity predictions. Looking forward, the major challenge is to understand how ecosystem processes will respond to compositional and relative abundance changes. This article is protected by copyright. All rights reserved

Observation and control of shock waves in individual nanoplasmas

In a novel experiment that images the momentum distribution of individual, isolated 100-nm-scale plasmas, we make the first experimental observation of shock waves in nanoplasmas. We demonstrate that the introduction of a heating pulse prior to the main laser pulse increases the intensity of the shock wave, producing a strong burst of quasi-monochromatic ions with an energy spread of less than 15%. Numerical hydrodynamic calculations confirm the appearance of accelerating shock waves, and provide a mechanism for the generation and control of these shock waves. This observation of distinct shock waves in dense plasmas enables the control, study, and exploitation of nanoscale shock phenomena with tabletop-scale lasers.Comment: 8 pages of manuscript, 9 pages of supplemental information, total 17 page