Archaeological sites and palaeoenvironments of Pleistocene West Africa

African paleoanthropological studies typically focus on regions of the continent such as Eastern, Southern and Northern Africa, which hold the highest density of Pleistocene archaeological sites. Nevertheless, lesser known areas such as West Africa also feature a high number of sites. Here, we present a high-resolution map synthesising all well contextualised Pleistocene archaeological sites present in Sub-Saharan West Africa. A detailed elevation and ecoregional map was developed and correlated with palaeoanthropological sites. This map is supplemented with 1,000- and 2000-year interval climate reconstructions over the last 120,000 years for three subregions of high archaeological interest. The presented archaeological sites were compiled by reviewing published literature, and selected based on: (1) documented archaeological stratification or >10 characteristic artefacts, (2) published coordinates, and (3) published chronometric ages or relative dating. The data presented here elucidates the current state of knowledge of Pleistocene West Africa, highlighting the regional potential for human evolutionary studies.1. Introduction 2. Data and methods 3. Map description 4. Discussio

Exploiting Cation Structure and Water Content in Modulating the Acidity of Ammonium Hydrogen Sulfate Protic Ionic Liquids

In this paper, we investigated the effect of cation structure and water content on proton dissociation in alkylammonium [HSO₄]⁻ protic ionic liquids (ILs) doped with 20 wt % water and correlated this with experimental Hammett acidities. For pure systems, increased cation substitution resulted in a reduction in the number of direct anion–anion neighbors leading to larger numbers of small aggregates, which is further enhanced with addition of water. We also observed spontaneous proton dissociation from [HSO₄]⁻ to water only for primary amine-based protic ILs, preceded by the formation of an anion trimer motif. Investigation using DFT calculations revealed spontaneous proton dissociation from [HSO₄]⁻ to water can occur for each of the protic ILs investigated; however, this is dependent on the size of the anion aggregates. These findings are important in the fields of catalysis and lignocellulosic biomass, where solvent acidity is a crucial parameter in biomass fractionation and lignin chemistry

Physiological and yield response in maize in cohesive tropical soil is improved through the addition of gypsum and leguminous mulch

Acknowledgements The Brazilian authors thank the Coordination for the Improvement of Higher Level Personnel (CAPES) and the National Council for Scientific and Technological Development (CNPq) for their support. Financial support The current work was undertaken as part of NUCLEUS, a virtual joint centre to deliver enhanced N-use efficiency via an integrated soil–plant systems approach for the United Kingdom and Brazil. Funded in Brazil by FAPESP – São Paulo Research Foundation [grant number 2015/50305-8]; FAPEG – Goiás Research Foundation [grant number 2015-10267001479] and FAPEMA – Maranhão Research Foundation [grant number RCUK-02771/16]; and in the United Kingdom by the Biotechnology and Biological Sciences Research Council [grant number BB/N013201/1] under the Newton Fund scheme.Peer reviewedPostprin

Electrical model of carbon fibre reinforced polymers for the development of electrical protection systems for more-electric aircraft

Carbon fibre reinforced polymers (CFRP) are increasingly used for structures on aircraft due to their superior mechanical properties compared to traditional materials, such as aluminium. Additionally, in order to improve aircraft performance, there is a continued trend for electrically driven loads on aircraft, increasing the on-board electrical power generation capacity and complexity of the electrical power system, including a desire to increase voltage levels and move towards DC distribution systems. Central to the reliable operation of an electrical power system is the development of an appropriate protection and fault management strategy. If an electrical earth fault occurs on a composite more-electric aircraft then the CFRP may form part of the route to ground. In order to develop an appropriate protection system and thus to understand the effects on engine generators it is necessary to investigate the fault response of this network. Hence a suitable electrical model of the CFRP material is required, which will enable CFRP to be included in a computationally-intensive systems-level simulation study of a more-electric aircraft (MEA) with fully switching power electronic converter models. This paper presents an experimentally validated impedance model of CFRP at an appropriate level of fidelity for use in systems level simulation platforms, enabling appropriate protection methods to be developed. The validated model considers the impact of the electrical bonding to ground, including the impedance added by a metallic frame that a CFRP panel may be mounted in. The simplicity of the model results in a less complex process to determine the expected impedance of the CFRP material, enabling a focus on the fault response of the system and subsequent development of appropriate protection solutions

Associative Stimulation of the Supraorbital Nerve Fails to Induce Timing-Specific Plasticity in the Human Blink Reflex

BACKGROUND: Associative high-frequency electrical stimulation (HFS) of the supraorbital nerve in five healthy individuals induced long-term potentiation (LTP)-like or depression (LTD)-like changes in the human blink reflex circuit according to the rules of spike timing-dependent plasticity (Mao and Evinger, 2001). HFS given at the onset of the R2 component of the blink reflex (HFS(LTP)) produced a lasting facilitation of the R2, whereas HFS given shortly before R2 (HFS(LTD)) caused a lasting suppression of the R2. In patients with benign essential blepharospasm (BEB), a focal dystonia affecting the orbicularis oculi muscles, HFS(LTP) induced excessive LTP-like associative plasticity relative to healthy controls, which was normalized after botulinum toxin (BTX) injections (Quartarone et al, 2006). METHODOLOGY/PRINCIPAL FINDINGS: We used HFS conditioning of the supraorbital nerve to study homeostatic metaplasticity of the blink reflex circuit in healthy subjects and dystonic patients. On separate days, we tested the conditioning effects on the R2 response and paired-pulse R2 inhibition after (i) HFS(LTP), (ii) HFS(LTP) followed by HFS(LTP), and (iii) HFS(LTP) followed by HFS(LTD). Controls also received (iv) HFS(LTD) alone and (v) a non-intervention protocol. In BEB patients, HFS(LTP) followed by HFS(LTD) was given before and after BTX treatment. We were not able to replicate the bidirectional timing-dependent effects of HFS(LTP) and HFS(LTD) alone. All HFS protocols produced a non-specific reduction of the R2 response and a relative decrease in paired-pulse inhibition. These R2 changes also occurred in controls when no HFS was applied. There was also no trace of a homeostatic response pattern in BEB patients before or after BTX treatment. CONCLUSION/SIGNIFICANCE: Our data challenge the efficacy of associative HFS to produce bidirectional plasticity in the human blink reflex circuit. The non-specific decrease of the R2 response might indicate habituation of the blink reflex following repeated electrical supraorbital stimulation. The increase of inhibition after paired pulse stimulation might reflect homeostatic behaviour to prevent further down regulation of the R2 response to preserve the protection of this adverse-effects reflex

Mesoporous tertiary oxides via a novel amphiphilic approach

We report a facile biomimetic sol-gel synthesis using the sponge phase formed by the lipid monoolein as a structure-directing template, resulting in high phase purity, mesoporous dysprosium- and gadolinium titanates. The stability of monoolein in a 1,4-butanediol and water mixture complements the use of a simple sol-gel metal oxide synthesis route. By judicious control of the lipid/solvent concentration, the sponge phase of monoolein can be directly realised in the pyrochlore material, leading to a porous metal oxide network with an average pore diameter of 10 nm