The tube-web spiders of the genus Ariadna (Araneae: Segestriidae) from South Australia and Victoria

The tube-web spider genus Ariadna Audouin, 1826 has been revised for South Australia and Victoria, revealing a remarkable diversity, particularly centred in the arid north of South Australia. We describe 23 species as new, ten of which are supported by molecular data, where these were available. We recognise two species groups for some of the species based on a combination of genitalic morphology, macrosetae patterns and somatic characters: the clavata species group, which includes Ariadna clavata Marsh, Baehr, Glatz & Framenau, 2018 and A. spinosa sp. nov. from South Australia, and A. otwayensis sp. nov. and A. sinuosa sp. nov. from Victoria, and the formosa species group, including A. formosa sp. nov. and A. umbra sp. nov. from South Australia, and A. tria sp. nov. from Victoria. Seventeen new species could not be placed into these two species groups: A. arenacea sp. nov., A. bellatula sp. nov., A. curvata sp. nov., A. deserta sp. nov., A. diucrura sp. nov., A. flavescens sp. nov., A. inflata sp. nov., A. insula sp. nov., A. pollex sp. nov., A. propria sp. nov., A. rutila sp. nov., Ariadna simplex sp. nov., A. subplana sp. nov., A. una sp. nov., A. ungua sp. nov., A. valida sp. nov. and A. woinarskii sp. nov. We provide updated diagnoses and distributional data for A. clavata and A. tangara Marsh, Baehr, Glatz & Framenau, 2018; however, the holotype of A. burchelli (Hogg, 1900) from Victoria could not be located for this project

Location, location, location: survival of Antarctic biota requires the best real estate.

The origin of terrestrial biota in Antarctica has been debated since the discovery of springtails on the first historic voyages to the southern continent more than 120 years ago. A plausible explanation for the long-term persistence of life requiring ice-free land on continental Antarctica has, however, remained elusive. The default glacial eradication scenario has dominated because hypotheses to date have failed to provide a mechanism for their widespread survival on the continent, particularly through the Last Glacial Maximum when geological evidence demonstrates that the ice sheet was more extensive than present. Here, we provide support for the alternative nunatak refuge hypothesis-that ice-free terrain with sufficient relief above the ice sheet provided refuges and was a source for terrestrial biota found today. This hypothesis is supported here by an increased understanding from the combination of biological and geological evidence, and we outline a mechanism for these refuges during successive glacial maxima that also provides a source for coastal species. Our cross-disciplinary approach provides future directions to further test this hypothesis that will lead to new insights into the evolution of Antarctic landscapes and how they have shaped the biota through a changing climate.Mark I. Stevens, and Andrew N. Mackintos

A molecular dynamics study on the equilibrium magnetization properties and structure of ferrofluids

We investigate in detail the initial susceptibility, magnetization curves, and microstructure of ferrofluids in various concentration and particle dipole moment ranges by means of molecular dynamics simulations. We use the Ewald summation for the long-range dipolar interactions, take explicitly into account the translational and rotational degrees of freedom, coupled to a Langevin thermostat. When the dipolar interaction energy is comparable with the thermal energy, the simulation results on the magnetization properties agree with the theoretical predictions very well. For stronger dipolar couplings, however, we find systematic deviations from the theoretical curves. We analyze in detail the observed microstructure of the fluids under different conditions. The formation of clusters is found to enhance the magnetization at weak fields and thus leads to a larger initial susceptibility. The influence of the particle aggregation is isolated by studying ferro-solids, which consist of magnetic dipoles frozen in at random locations but which are free to rotate. Due to the artificial suppression of clusters in ferro-solids the observed susceptibility is considerably lowered when compared to ferrofluids.Comment: 33 pages including 12 figures, requires RevTex

Antarctic biodiversity predictions through substrate qualities and environmental DNA

Antarctic conservation science is crucial for enhancing Antarctic policy and understanding alterations to terrestrial Antarctic biodiversity. Antarctic conservation will have limited long-term impacts in the absence of large-scale biodiversity data, but if such data were available, it is likely to improve environmental protection regimes. To enable the prediction of Antarctic biodiversity across continental spatial scales through proxy variables, in the absence of baseline surveys, we linked Antarctic substrate-derived environmental DNA (eDNA) sequence data from the remote Antarctic Prince Charles Mountains to a selected range of concomitantly collected measurements of substrate properties. We achieved this through application of a statistical method commonly used in machine learning. Our analysis indicated that neutral substrate pH, low conductivity, and certain substrate minerals are important predictors of the presence of basidiomycetes, chlorophytes, ciliophorans, nematodes, and tardigrades. A bootstrapped regression revealed how variations in the identified substrate parameters influence probabilities of detecting eukaryote phyla across vast and remote areas of Antarctica. We believe that our work will improve future taxon distribution modeling and aid in developing more targeted surveys of biodiversity conducted under logistically challenging conditions.Paul Czechowski, Michel de Lange, Michael Knapp, Aleks Terauds, and Mark I Steven

The use of different 16S rRNA gene variable regions in biogeographical studies.

16S rRNA gene amplicon sequencing is routinely used in environmental surveys to identify microbial diversity and composition of the samples of interest. The dominant sequencing technology of the past decade (Illumina) is based on the sequencing of 16S rRNA hypervariable regions. Online sequence data repositories, which represent an invaluable resource for investigating microbial distributional patterns across spatial, environmental or temporal scales, contain amplicon datasets from diverse 16S rRNA gene variable regions. However, the utility of these sequence datasets is potentially reduced by the use of different 16S rRNA gene amplified regions. By comparing 10 Antarctic soil samples sequenced for five different 16S rRNA amplicons, we explore whether sequence data derived from diverse 16S rRNA variable regions can be validly used as a resource for biogeographical studies. Patterns of shared and unique taxa differed among samples as a result of variable taxonomic resolutions of the assessed 16S rRNA variable regions. However, our analyses also suggest that the use of multi-primer datasets for biogeographical studies of the domain Bacteria is a valid approach to explore bacterial biogeographical patterns due to the preservation of bacterial taxonomic and diversity patterns across different variable region datasets. We deem composite datasets useful for biogeographical studies.Gilda Varliero, Pedro H. Lebre, Mark I. Stevens, Paul Czechowski, Thulani Makhalanyane, Don A. Cowa

Ultrafast quasiparticle relaxation dynamics in normal metals and heavy fermion materials

We present a detailed theoretical study of the ultrafast quasiparticle relaxation dynamics observed in normal metals and heavy fermion materials with femtosecond time-resolved optical pump-probe spectroscopy. For normal metals, a nonthermal electron distribution gives rise to a temperature (T) independent electron-phonon relaxation time at low temperatures, in contrast to the T^{-3}-divergent behavior predicted by the two-temperature model. For heavy fermion compounds, we find that the blocking of electron-phonon scattering for heavy electrons within the density-of-states peak near the Fermi energy is crucial to explain the rapid increase of the electron-phonon relaxation time below the Kondo temperature. We propose the hypothesis that the slower Fermi velocity compared to the sound velocity provides a natural blocking mechanism due to energy and momentum conservation laws.Comment: 10 pages, 11 figure

Magnetic Anisotropy in the Molecular Complex V15

We apply degenerate perturbation theory to investigate the effects of magnetic anisotropy in the magnetic molecule V15. Magnetic anisotropy is introduced via Dzyaloshinskii-Moriya (DM) interaction in the full Hilbert space of the system. Our model provides an explanation for the rounding of transitions in the magnetization as a function of applied field at low temperature, from which an estimate for the DM interaction is found. We find that the calculated energy differences of the lowest energy states are consistent with the available data. Our model also offers a novel explanation for the hysteretic nature of the time-dependent magnetization data.Comment: Final versio

The Stroop revisited: a meta-analysis of interference control in AD/HD

Background: An inhibition deficit, including poor interference control, has been implicated as one of the core deficits in AD/HD. Interference control is clinically measured by the Stroop Colour-Word Task. The aim of this meta-analysis was to investigate the strength of an interference deficit in AD/HD as measured by the Stroop Colour-Word Task and to assess the role of moderating variables that could explain the results. These moderating variables included: methods of calculating the interference score, comorbid reading and psychiatric disorders, AD/HD-subtypes, gender, age, intellectual functioning, medication, and sample size. Methods: Seventeen independent studies were located including 1395 children, adolescents, and young adults, in the age range of 6-27 years. A meta-analysis was conducted to assess the effect sizes for the scores on the word and the colour card as well as the interference score. Results: Children with AD/HD performed more poorly on all three dependent variables. The effect sizes for word reading (d = .49) and colour naming (d = .58) were larger and more homogeneous than the effect size for the interference score (d = .35). The method used to calculate the interference score strongly influenced the findings for this measure. When interference control was calculated as the difference between the score on the colour card minus the score on the colour-word card, no differences were found between AD/HD groups and normal control groups. Discussion: The Stroop Colour-Word Task, in standard form, does not provide strong evidence for a deficit in interference control in AD/HD. However, the Stroop Colour-Word Task may not be a valid measure of interference control in AD/HD and alternative methodologies may be needed to test this aspect of the inhibitory deficit model in AD/HD. © Association for Child Psychology Psychiatry, 2004

Scoping future research for air pollution recovery indicators (APRI). (Workshop report)

Atmospheric nitrogen (N) pollution is a major and ongoing cause of biodiversity loss across the UK, but in some locations N pollution pressures have been declining. In response to these dynamics, JNCC requested a workshop to help to scope Phase 2 of the Air Pollution Recovery Indicators (APRI) project. The damaging effects of excess N load and of gaseous ammonia on many ecosystems are clear. However, the processes and timescales of ecosystem recovery following a decrease in pollution pressure are less well understood. The APRI project aims to take practical steps to fill this knowledge gap by delivering new scientific research focused on indicators of ecosystem and species recovery from N pollution. In Phase 1, predominantly below-ground responses are being studied at a dry heathland site where experimental additions of N were made between 1998 and 2011, revealing lingering effects on soil chemistry, the soil fungi community and vegetation structure (Kowal et al. 2024). The effect on mycorrhizal fungi, and using these fungi as recovery indicators, is being examined in more detail with recently established assessment methods (Arrigoni et al. 2023). Phase 2 of APRI will consider recovery from N impacts more broadly, e.g. by studying other habitats or species. Further empirical research may be commissioned to better understand recovery pathways from air pollution. A workshop was held on 7–8 November 2023 to help develop an action plan for the remainder of the APRI project. This report summarises the workshop discussion and ensuing work. We note that the focus of the APRI project is on assessing recovery. It is therefore essential to contrast responses of ecosystems subject to decreased pollution pressure with indicators from ecosystems experiencing ongoing pollution. Properties that have been used previously to assess impacts can be used to understand recovery, and novel indicators of ecosystem change are also likely to be useful for assessing recovery. Whatever indicators are chosen to assess change, benchmarking data will be needed to assess the range of potential values and relationships with N deposition. Results from the workshop and subsequent discussions include: • Eleven criteria to help choose appropriate indicators in relation to declining N deposition: Speed of response, Sensitivity of response, Specificity of response, Generality to multiple habitats, Relatedness to recovery endpoints, Previous use, Breadth of pollution gradient, Added value to other policy areas, Resilience in face of anticipated change, Feasibility of collection, Measurement uncertainty. • The need to consider a basket of indicators to indicate recovery from N pollution. Such a basket could include examples from different categories e.g. indicators of pressure, biogeochemical response indicators, and biotic response indicators, with individual indicators likely responding over different timescales. The exact choice may depend on the habitat concerned and the availability of prior data, as well as the question being posed and/or policy goal. • Explicit recommendations on sites to target in APRI Phase 2 to gain information on recovery indicator trajectories, namely (i) well-designed field experiments where N addition has ceased, and (ii) point sources of emissions that have ceased to operate, preferably with a super-imposition of an experimental treatment or treatments. Given uncertainties associated with modelled historical, contemporary, and future N deposition and the potential for confounding variables, analysing survey data from across the UK will be unlikely to provide robust information within the timeframes of the APRI Phase 2. We recommend further assessments may help develop detailed plans for empirical work in Phase 2 of APRI. Potential next steps are to: • Finalise a list of potential and priority indicators of recovery from air pollution (which may differ by habitat type), specifically from high levels of N deposition and/or high atmospheric reactive N concentrations. This finalisation could be done through active participation of the air pollution community and the completion of ‘live’ spreadsheets that address potential indicator criteria. • Summarise relevant data on recovery indicators, across key semi-natural habitats. This summary should include data available from other countries with similar environmental contexts, to help disentangle drivers of change in the UK context. This evidence will help understand recovery pathways from air pollution. As above, this could be done through the active participation of the air pollution community and the completion of ‘live’ spreadsheets. Such an approach could also enable gap analyses, for example identifying where we are missing information by habitat and/or environmental conditions. • Identify areas where co-located monitoring of N with existing habitat/species monitoring could enhance the likelihood for establishing recovery indicators. This should enhance other similar activity such as through the Natural Capital and Ecosystem Assessment programme and the UK Air Pollution Impacts on Ecosystems Networks (APIENs). • Develop a list of priority habitats and sites where empirical research is needed to better understand recovery pathways, including a gap analysis of habitats, methods and/or indicators. • Encourage activities that enhance understanding of ammonia emission sources at local scale (e.g. 1 km or less), to help better identify areas where N pollution has decreased, and recovery might be detected. This could include intensive monitoring or collating and sharing information about permitted N sources. • Develop case studies, including potentially from APRI Phase 1, to demonstrate how existing evidence on localised recovery in semi-natural habitats of conservation importance can be used by policy- and decision-makers to help drive policy toward continued reductions in emissions of reactive N

Neurodevelopmental risk factors in schizophrenia

The authors review environmental and neurodevelopmental risk factors for schizophrenic disorders, with emphasis on minor physical anomalies, particularly craniofacial anomalies and dermatoglyphic variations. The high prevalence of these anomalies among schizophrenic subjects supports the neurodevelopmental theory of the etiology of schizophrenia, since they suggest either genetically or epigenetically controlled faulty embryonic development of structures of ectodermal origin like brain and skin. This may disturb neurodevelopment that in turn may cause these subjects to be at increased risk for the development of schizophrenia and related disorders. The precise confirmation of this theory, at least in some cases, will provide further understanding of these illnesses, allowing easy and inexpensive identification of subjects at risk and providing guidelines for the development of new pharmacological interventions for early treatment and even for primary prevention of the illness