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Cobalt‐iron oxyhydroxides (CoFeOOHx) are among the most active catalysts for the oxygen evolution reaction (OER). However, their redox behavior and the electronic and chemical structure of their active sites are still ambiguous. To shed more light on this, the complete and rapid reconstruction of four helical cobalt‐iron borophosphates with different Co:Fe ratios into disordered cobalt‐iron oxyhydroxides can be achieved, which are electrolyte‐penetrable and thus most transition metal sites can potentially participate in the OER. To track the redox behavior and to identify the active structure, quasi in situ X‐ray absorption spectroscopy is applied. Iron in high oxidation states ≥ IV (Fe4+) and its substantial redox behavior with an average oxidation state of around 2.8 to above 3.2 is detected. Furthermore, a 6% contraction of the Fe‐O bond length compared to Fe3+OOH references is observed during OER and a strong distortion of the [MO6] octahedra is identified. It is hypothesized that this bond contraction is caused by the presence of oxyl radicals and that di‐µ‐oxyl radical bridged cobalt‐iron centers are the active sites. It is anticipated that the detailed electronic and structural description can substantially contribute to the debate on the nature of the active site in bimetallic iron‐containing OER catalysts.

Nanocrystalline or amorphous cobalt oxyhydroxides (CoCat) are promising electrocatalysts for the oxygen evolution reaction (OER). While having the same short range order, CoCat phases possess different electrocatalytic properties. This phenomenon is not conclusively understood, as multiple interdependent parameters affect the OER activity simultaneously. Herein, a layered cobalt borophosphate precatalyst, Co(H2O)2[B2P2O8(OH)2]∙H2O, is fully reconstructed into two different CoCat phases. In marked contrast to previous reports, this reconstruction is not initiated at the surface but at the electrode substrate to catalyst interface. Ex- and in situ investigations of the two borophosphate derived CoCats, as well as the prominent CoPi and CoBi identify differences in the Tafel slope/range, buffer binding and content, long-range order, number of accessible edge sites, redox activity, and morphology. Considering and interconnecting these aspects together with proton mass transport limitations, we provide a comprehensive picture explaining the different OER activities. The most decisive factors are the buffers used for reconstruction, the number of edge sites that are not inhibited by irreversibly bond buffers, and the morphology of the catalysts. With this acquired knowledge, an optimized OER system is realized operating in near neutral potassium borate media at 1.62±0.03 VRHE yielding 250 mA/cm² at 65 °C for one month without degrading performance.

Based on the low cost and relatively high catalytic activity, considerable efforts have been devoted towards developing redox active transition metal TM oxygen electrocatalysts for the alkaline oxygen evolution reaction OER while the role of redox inactive alkaline earth metals has often been neglected in OER. Herein, for the first time, we developed a novel ternary intermetallic CaFe6Ge6 precatalyst, whose surface rapidly transforms into a porous ultrathin Ca amp; 8722;Fe amp; 8722;O heteroshell structure during alkaline OER through the oxidative leaching of surficial Ge. Benefiting from synergistic effects, this highly efficient OER active material with distinct Ca amp; 8722;Fe amp; 8722;O layers has a large electrochemical surface area and more exposed active Fe sites than a Ca free FeOx phase. Also, the presence of Ca in Ca amp; 8722;Fe amp; 8722;O is responsible for the enhanced transport and activation of hydroxyls and related OER reaction intermediate as unequivocally illustrated by a combination of quasi in situ Raman spectroscopy and various ex situ methods

Identifying novel classes of precatalysts for the oxygen evolution reaction (OER by water oxidation) with enhanced catalytic activity and stability is a key strategy to enable chemical energy conversion. The vast chemical space of intermetallic phases offers plenty of opportunities to discover OER electrocatalysts with improved performance. Herein we report intermetallic nickel germanide (NiGe) acting as a superior activity and durable Ni‐based electro(pre)catalyst for OER. It is produced from a molecular bis(germylene)‐Ni precursor. The ultra‐small NiGe nanocrystals deposited on both nickel foam and fluorinated tin oxide (FTO) electrodes showed lower overpotentials and a durability of over three weeks (505 h) in comparison to the state‐of‐the‐art Ni‐, Co‐, Fe‐, and benchmark NiFe‐based electrocatalysts under identical alkaline OER conditions. In contrast to other Ni‐based intermetallic precatalysts under alkaline OER conditions, an unexpected electroconversion of NiGe into γ‐NiIIIOOH with intercalated OH−/CO3 2− transpired that served as a highly active structure as shown by various ex situ methods and quasi in situ Raman spectroscopy., A xanthene‐based bis(germylene)‐Ni complex is used as a molecular precursor for the synthesis of ultra‐small NiGe nanostructures, which can generate a γ‐NiOOH structure with intercalated species. This displays exceptional catalytic activity and long‐term durability for the oxygen evolution reaction (OER).

Herein, we report on intermetallic iron germanide (Fe6Ge5) as a novel oxygen evolution reaction (OER) precatalyst with a Tafel slope of 32 mV dec−1 and an overpotential of 272 mV at 100 mA cm−2 in alkaline media. Furthermore, we uncover the in situ formation of a core–shell like structure that slowly collapses under OER conditions.

Electrocatalytic water splitting is the key process for the formation of green fuels for energy transport and storage in a sustainable energy economy. Besides electricity, it requires water, an aspect that seldomly has been considered until recently. As freshwater is a limited resource (

This talk will outline how the immediate impact of climatic events on societies of the past can be identified and quantified more robustly by archaeological research using mollusc shell records.Advances in data acquisition regarding speed and resolution promise improved access to this high-resolution climate archive, and thus an improved interdisciplinary palaeo-perspective. Different to most long-term climate archives, mollusc shells are often found on site and record temperature changes on a seasonal scale, allowing us to measure weather extremes on a resolution that a) would have been immediately noticeable by individuals and b) is essential to subsistence strategies. In particular, we hope to provide a better environmental backdrop to the question of the climatic impact on the Neolithic Dispersal along the Mediterranean coasts and verify extreme short-term events on site, should they have occurred.We are employing an innovative way of acquiring sea surface temperature (SST) data using a combined approach of stable oxygen isotopes (δ18O) and LIBS-screening (Laser Induced Breakdown Spectroscopy), resulting in a lower quantity of δ18O values required per shell and, as a result, a higher quantity of sampled shells. Our improved data acquisition process enables us to use a high resolution (i.e. +1000 data points per shell record) as well as a high sample quantity (100s of shells) approach, that provides extensive coverage across entire site stratigraphies. By sourcing our climate data from shell remains found in archaeological layers, we are able to directly compare archaeological information of that layer with the individual climate records, side-stepping the need of radiocarbon-dating either dataset extensively and instead using the shared stratigraphic position to infer temporal concurrence.This high quantity and high resolution approach produces a combined natural and societal archive, that because of its size can more easily and robustly reveal links between society and the immediate climate change, extreme events and natural hazards it experienced.

The role of seasonality is indisputable in climate and ecosystem dynamics. Seasonal temperature and precipitation variability are of vital importance for the availability of food, water, shelter, migration routes, and raw materials. Thus, understanding past climatic and environmental changes at seasonal scale is equally important for unearthing the history and for predicting the future of human societies under global warming scenarios. Alas, in palaeoenvironmental research, the term ‘seasonality change’ is often used liberally without scrutiny or explanation as to which seasonal parameter has changed and how.\ud \ud Here we provide fundamentals of climate seasonality and break it down into external (insolation changes) and internal (atmospheric CO2 concentration) forcing, and regional and local and modulating factors (continentality, altitude, large-scale atmospheric circulation patterns). Further, we present a brief overview of the archives with potentially annual/seasonal resolution (historical and instrumental records, marine invertebrate growth increments, stalagmites, tree rings, lake sediments, permafrost, cave ice, and ice cores) and discuss archive-specific challenges and opportunities, and how these limit or foster the use of specific archives in archaeological research.\ud \ud Next, we address the need for adequate data-quality checks, involving both archive-specific nature (e.g., limited sampling resolution or seasonal sampling bias) and analytical uncertainties. To this end, we present a broad spectrum of carefully selected statistical methods which can be applied to analyze annually- and seasonally-resolved time series. We close the manuscript by proposing a framework for transparent communication of seasonality-related research across different communities.

The oxygen evolution reaction (OER) and the value-added selective oxidation of renewable organic substrates are the most promising reactions to supply electrons and protons for the synthesis of sustainable fuels. To meet industrial requirements, new methods for a simple, fast, environmentally friendly, and cheap synthesis of robust, self-supported, high surface area electrodes are required. Herein, we report on a novel in liquid plasma electrolysis approach for the growth of hierarchical nanostructures on nickel foam. Under retention of the morphology, iron could be incorporated into this high surface area electrode. For the oxidation of 5-hydroxymethylfurfural and benzyl alcohol, the iron free plasma treated electrode is more suitable reaching current densities up to 800 mA/cm² with Faradaic efficiencies above 95%. For the OER, the iron incorporated nickel foam electrode reached the industrially relevant current density of 500 mA/cm² at 1.473±0.013 VRHE (60 °C) and showed no activity decrease over 140 h. The different effects of the iron doping is rationalised using MeOH doping and in situ Raman spectroscopy. Furthermore, we could separate changes in intrinsic activity per active site and number of active sites for the OER as well as reveal diffusion limitations of the organic oxidation reactions which we explain with respect to the surface morphology. We anticipate that the plasma modified high surface area nickel foam could potentially be applied for various electrocatalytic processes.

As the kinetically demanding oxygen evolution reaction (OER) is crucial for the decarbonization of our society, a wide range of (pre)catalysts with various non-active-site elements (e.g., Mo, S, Se, N, P, C, Si…) have been investigated. Thermodynamics dictate that these elements oxidize during industrial operation. The formed oxyanions are water soluble and thus predominantly leach in a reconstruction process. Nevertheless, recently, it was unveiled that these thermodynamically stable (oxy)anions can adsorb on the surface or intercalate in the interlayer space of the active catalyst. There, they tune the electronic properties of the active sites and can interact with the reaction intermediates, changing the OER kinetics and potentially breaking the persisting OER *OH/*OOH scaling relations. Thus, the addition of (oxy)anions to the electrolyte opens a new design dimension for OER catalysis and the herein discussed observations deepen the understanding of the role of anions in the OER.

The continuous increase in the population and industrial development has led to an increase in global energy demand. Most of the current primary energy consumption is obtained from the burning of fossil fuels that releases an enormous amount of greenhouse gases. Notably, hydrogen (H2) is a clean and eco-friendly fuel and has already shown its ability to be a promising substitute for fossil energy. One of the cleanest ways to produce H2 is by splitting of water by electrolysis.1 Recently, numerous inexpensive and robust catalysts based on transition metals (oxides, chalcogenides, pnictides, carbides, or alloys, etc.) have been developed for water splitting with reasonable activity.2 Despite the massive development of electrocatalysts for water splitting, huge challenges still exist for their use in practical application. Our current goals are to uncover new classes of suitable unconventional catalysts based on non-noble metals that can offer better overall catalytic efficiency for practical applications; to study their structural transformation, active sites, surface, and bulk structures; and to investigate the influence of precatalysts on the properties of the final catalyst. In this context, intermetallic compounds have numerous advantages owing to their intriguing structural, chemical and physical properties, especially being catalytically active and electrically conductive at the same time and thus, making them an ideal class of materials for electrocatalytic applications.3 Using different approaches, we synthesized various classes of intermetallic materials (e.g., stannides, gallides, germanides, indates, silicides, etc.) with interesting structural and electronic features.4-5 Most of these materials exhibited remarkable electrocatalytic activity for water splitting, yielding considerably low overpotentials with enhanced long-term durability for both O2 and H2 generation in alkaline media. The active catalyst structure during each half-reaction (H2 and O2) and the correlation of the structure with the activity of the catalysts were revealed by a profound understanding of the system using in-situ and ex-situ techniques. This talk will provide a brief summary of the ongoing water splitting research as well as delve into selected examples of our recent work to pave the way to a concept-guided design system beyond water electrolysis (e.g., paired electrolysis). References [1] H Yang, M Driess, P. W. Menezes, Adv. Energy Mater. 2021, 11, 2102074. [2] Z Chen, H Yang, Z Kang, M Driess, P. W. Menezes, Adv. Mater. 2022, 2108432. [3] C. Walter, P. W. Menezes, M. Driess, Chem. Sci. 2021, 12, 8603. [4] N. Hausmann, R. Beltrán-Suito, S. Mebs, V. Hlukhyy, T. F. Fässler, H. Dau, M. Driess, P. W. Menezes, Adv. Mater. 2021, 33, 2008823. [5] B. Chakraborty, R. Beltrán-Suito, S. Garai, J. N. Hausmann, M. Driess, P. W. Menezes, Adv. Energy Mater. 2020, 10, 2001377.

The oxygen evolution reaction (OER) is the most likely reaction to supply electrons and protons for future green fuel and chemical formation, and thus many materials have been studied for their suitability as OER (pre)catalysts. However, in-situ and post-catalytic studies have shown that the harsh OER conditions alter the electrode materials, causing a reconstruction to mainly transition metal oxyhydroxides in alkaline and near-neutral electrolyte. As this reconstructed phase is the real catalyst, its atomic structure and physical properties must be precisely known. These properties will be affected by the precatalyst and the reconstruction conditions, like the product of a chemical reaction is affected by the substrate and reaction conditions. For the elucidation of such reconstruction processes, a broad range of spectroscopic (in-situ) methods combined with new, meaningful precursors are required. Herein, investigations on the reconstruction of several precatalysts such as phosphites,1 borophosphates,2 selenites,3 silicides,4 and elemental metal foams are presented. These reconstructions were analysed by in situ Raman and X-ray absorption spectroscopy together with state-of-the-art post-mortem characterization techniques. In an effort to connect this data, we propose ideas relating the precatalyst structure with the one of the formed oxyhydroxides. Additionally, we critically debate the question: why should a non-oxyhydroxide phase be used for the OER if it will anyway reconstruct? Moreover, as mentioned, also the reconstruction conditions affect the specific nature of the formed oxyhydroxide. Considering this, we present a case, where from the same precatalyst, catalysts with entirely different structural and electrocatalytic properties were obtained by only changing the electrochemical reconstruction conditions (potential, pH, electrolyte composition...). References: Menezes, P. W. et al. A structurally versatile nickel phosphite acting as a robust bifunctional electrocatalyst for overall water splitting. Energy Environ. Sci. 11, 0–13 (2018). Menezes, P. W. et al. Helical cobalt borophosphates to master durable overall water-splitting. Energy Environ. Sci. 12, 988–999 (2019). Hausmann, J. N. et al. Understanding the formation of bulk- and surface-active layered (oxy)hydroxides for water oxidation starting from a cobalt selenite precursor. Energy Environ. Sci. 13, 3607–3619 (2020). Hausmann, J. N. et al. Evolving Highly Active Oxidic Iron(III) Phase from Corrosion of Intermetallic Iron Silicide to Master Efficient Electrocatalytic Water Oxidation and Selective Oxygenation of 5‐Hydroxymethylfurfural. Adv. Mater. 33, 2008823 (2021). Figure 1

In a green energy economy, electrocatalysis is essential for chemical energy conversion and to produce value added chemicals from regenerative resources. To be widely applicable, an electrocatalyst should comprise the Earth's crust's most abundant elements. The most abundant 3d metal, iron, with its multiple accessible redox states has been manifold applied in chemocatalytic processes. However, due to the low conductivity of FeIII Ox Hy phases, its applicability for targeted electrocatalytic oxidation reactions such as water oxidation is still limited. Herein, it is shown that iron incorporated in conductive intermetallic iron silicide (FeSi) can be employed to meet this challenge. In contrast to silicon-poor iron-silicon alloys, intermetallic FeSi possesses an ordered structure with a peculiar bonding situation including covalent and ionic contributions together with conducting electrons. Using in situ X-ray absorption and Raman spectroscopy, it could be demonstrated that, under the applied corrosive alkaline conditions, the FeSi partly forms a unique, oxidic iron(III) phase consisting of edge and corner sharing [FeO6 ] octahedra together with oxidized silicon species. This phase is capable of driving the oxyge evolution reaction (OER) at high efficiency under ambient and industrially relevant conditions (500 mA cm-2 at 1.50 ± 0.025 VRHE and 65 °C) and to selectively oxygenate 5-hydroxymethylfurfural (HMF).

A facile synthetic route to NiPt3@NiS heteronanostructures is reported, starting from a subsulfido bridged heterobimetallic nickel-platinum molecular precursor. Notably, the NiPt3@NiS on nickel foam displayed merely an overpotential of 12 mV at -10 mA cm-2, which is substantially lower than that of Pt or NiS, synthesized through a similar approach and represents the most active hydrogen evolution reaction (HER) electrocatalysts yet reported in alkaline solutions. NiPt3@NiS electrodes demonstrated an unceasing HER stability over 8 days, which is well over those reported for Pt-based catalysts signifying a capability of scaled hydrogen production.

Elemental analysis of biogeochemical archives is an established technique used to study climate in a range of applications, including ocean circulation, glacial/interglacial climates, and anthropogenic climate change. Data from mollusc archives are especially important because of their global abundance and sub-annual resolution. Despite this potential, they are underrepresented among palaeoclimate studies, due to enigmatic physiological influences skewing the elemental record. Understanding the patterns behind these influences will improve data interpretation and lead to the development of new climate proxies. Here, we show for the first time that extensive spatial mapping of multiple mollusc specimens using Laser Induced Breakdown Spectroscopy (LIBS) across a wider region can resolve enigmatic patterns within the elemental record caused by physiological influences. 2D elemental (Mg/Ca) maps of whole limpet shells (Patella caerulea) from across the Mediterranean revealed patterns of variability within individual mollusc records as well as within isochronous parts of specimens. By registering and quantifying these patterns, we established previously uninterpretable correlations with temperature (R2 > 0.8, p

The development of novel earth abundant metal based catalysts to accelerate the sluggish oxygen evolution reaction OER is crucial for the process of large scale production of green hydrogen. To solve this bottleneck, herein, a simple one pot colloidal approach is reported to yield crystalline intermetallic nickel silicide Ni2Si , which results in a promising precatalyst for anodic OER. Subsequently, an anodic coupled electrosynthesis for the selective oxidation of organic amines as sacrificial proton donating agents to value added organocyanides is established to boost the cathodic reaction. A partial transformation of the Ni2Si intermetallic precatalyst generates a porous nickel oxy hydroxide phase modified with oxidic silicon species as unequivocally demonstrated by a combination of quasi in situ Raman and X ray absorption spectroscopy as well as ex situ methods. The activated form of the catalyst generates a geometric current density of 100 mA cm amp; 8722;2 at an overpotential amp; 951;100 of 348 mV displaying long term durability over a week and high efficiency in paired electrolysis

Marine faunal remains from Grotta d’Oriente (Favignana Island, NW Sicily) offer invaluable snapshots of human-coastal environment interaction in the central Mediterranean from the Late Pleistocene to the Middle Holocene. The long-term shellfish and fish records reflect human exploitation of coastal environments undergoing considerable reorganizations during the postglacial sea level rise and the progressive isolation of Favignana from mainland Sicily. We detected an intensification of marine resource exploitation between ∼9.6 ka and ∼7.8 ka BP, which corresponds with the isolation of Favignana Island and, later on, with the introduction of early agro-pastoral economy in this region. We suggest that a higher investment in marine resource exploitation by late foragers and early farmers in NW Sicily was also supported by an increase in marine productivity in the south Tyrrhenian Sea in the Middle Holocene.

Herein, we report on intermetallic iron germanide (Fe6Ge5) as a novel oxygen evolution reaction (OER) precatalyst with a Tafel slope of 32 mV dec-1 and an overpotential of 272 mV at 100 mA cm-2 in alkaline media. Furthermore, we uncover the in situ formation of a core-shell like structure that slowly collapses under OER conditions.

One of the key catalytic reactions for life on earth, the oxidation of water to molecular oxygen, occurs in the oxygen-evolving complex of the photosystem II (PSII) mediated by a manganese-containing cluster. Considerable efforts in this research area embrace the development of efficient artificial manganese-based catalysts for the oxygen evolution reaction (OER). Using artificial OER catalysts for selective oxygenation of organic substrates to produce value-added chemicals is a worthwhile objective. However, unsatisfying catalytic performance and poor stability have been a fundamental bottleneck in the field of artificial PSII analogs. Herein, for the first time, a manganese-based anode material is developed and paired up for combining electrocatalytic water oxidation and selective oxygenations of organics delivering the highest efficiency reported to date. This can be achieved by employing helical manganese borophosphates, representing a new class of materials. The uniquely high catalytic activity and durability (over 5 months) of the latter precursors in alkaline media are attributed to its unexpected surface transformation into an amorphous MnOx phase with a birnessite-like short-range order and surface-stabilized Mn-III sites under extended electrical bias, as unequivocally demonstrated by a combination of in situ Raman and quasi in situ X-ray absorption spectroscopy as well as ex situ methods.

The urgent need for a stable, efficient, and affordable oxygen evolution reaction (OER) catalyst has led to the investigation of a vast amount of transition metal materials with multiple different anions. In situ and post catalytic characterization shows that most materials transform during the harsh OER conditions to layered (oxy)hydroxides (LOH). Several open questions concerning these in situ formed LOH remain such as: an explanation for their strongly varying activities, or the effect of the precatalyst structure, leaching anions, and transformation conditions on the formed LOH. Herein, we report on a cobalt selenite precursor, which, depending on pH and potential, transforms irreversibly into two different LOH OER catalysts. Combining multiple electrochemical and analytical methods ex and in situ, we prove that one of these products is near-surface catalytically active and the other one throughout the bulk with an in situ average cobalt oxidation state of 3.2. We deduce a detailed structural model explaining these differences and propose general concepts relating both the precatalyst structure and the transformation conditions to the final catalyst. Further, we apply these models to the most promising non-noble metal catalyst, NiFe LOH.

© 2020 Elsevier Ltd and INQUA Intertidal environments have been the main source for mollusc gathering and consumption for at least the last 164,000 years. However, our knowledge of long-term trends is compromised by the fact that the majority of Pleistocene and early Holocene shorelines, and in turn their archaeological sites, are either currently submerged under water or have long been destroyed by sea-level change. Ecological information on the resilience of intertidal resources is crucial in assessing how attractive they were to past humans as a long-term source of food. Of particular interest is the southern Red Sea and its function as the southern gateway out of Africa into Arabia during a period of aridity. The role that marine food sources likely played in this dispersal is underplayed and largely ignored when interpreting periods of terrestrial aridity. Here we analyse the resilience of Conomurex fasciatus and report size measurements of over 15,000 specimens from the Holocene shell middens on the Farasan Islands, Saudi Arabia, as an ecological baseline for prehistoric shellfish exploitation to determine the long-term sustainability of shellfish harvesting in an arid environment. Changes in shell-size and relative abundance can indicate whether a species was subjected to changes in the intensity of human harvests and we use this dataset to reconstruct how the species was affected by a known intense exploitation period between 7360 and 4780 cal BP. Our results indicate no signs of resource depletion throughout the occupation period and add to the growing body of evidence that marine resources along arid shorelines are an important part of a mixed diet. Further, by measuring size changes occurring during early life stages of C. fasciatus we were able to reveal changes in size that were unaffected by human harvesting pressure and instead suggest patch-selection as the main control. These results have implications for the interpretation of shellfish harvesting during periods of terrestrial aridity and specifically the potential of shellfish as a reliable food source during Palaeolithic migrations out of Africa.

An unprecedented molecular 2Fe–2As precursor complex was synthesized and transformed under soft reaction conditions to produce an active and long-term stable nanocrystalline FeAs material for electrocatalytic water oxidation in alkaline media. The 2Fe2As-centred β-diketiminato complex, having an unusual planar Fe2As2 core structure, results from the salt-metathesis reaction of the corresponding β-diketiminato FeIICl complex and the AsCO− (arsaethynolate) anion as the monoanionic As− source. The as-prepared FeAs phase produced from the precursor has been electrophoretically deposited on conductive electrode substrates and shown to act as a electro(pre)catalyst for the oxygen evolution reaction (OER). The deposited FeAs undergoes corrosion under the severe anodic alkaline conditions which causes extensive dissolution of As into the electrolyte forming finally an active two-line ferrihydrite phase (Fe2O3(H2O)x). Importantly, the dissolved As in the electrolyte can be fully recaptured (electro-deposited) at the counter electrode making the complete process eco-conscious. The results represent a new and facile entry to unexplored nanostructured transition-metal arsenides and their utilization for high-performance OER electrocatalysis, which are also known to be magnificent high-temperature superconductors., A molecularly derived FeAs has been used as an electro(pre)catalyst for an efficient alkaline OER for the first time and subsequently, its active structure has been determined by quasi in situ X-ray absorption spectroscopy and ex situ methods.

Copyright © 2017 Taylor & Francis Group, LLC. Here we present the results of the analysis of coastal exploitation patterns in the southern Red Sea during the Middle Holocene. We focus on the shell midden cluster of the Farasan Islands, Saudi Arabia, which comprises over 3,000 shell midden sites. These sites date from 6,500 to 4,500 cal BP and are part of an arid landscape. We focus on one site, JW1727, which provides a snapshot of marine exploitation and will help to understand the use of food resources within the region. Stable isotope values (δ18O) were collected from the marine gastropod Conomurex fasciatus (Born 1778), which represents 72% of shell weight of JW1727, in order to reconstruct the season of capture. Results demonstrate that 1) every season is represented within the dataset; and 2) there is increased C. fasciatus deposition during the summer and autumn months. This indicates a diet consisting of C. fasciatus throughout the year in combination with other food sources and an increase of the C. fasciatus component during the arid seasons, possibly linked to the unavailability of vegetation. Additionally, size measurements of C. fasciatus were carried out to examine changes in size distribution throughout the occupation of the site that could be related to overexploitation of C. fasciatus. However, no significant trends could be observed. In sum, the results suggest a sustainable and constant habitation of the Farasan Islands despite the highly arid conditions.

In order to investigate the position of the strontium deficiency in superconductive S r 3 − x SnO, we synthesized and measured X-ray-diffraction patterns of S r 3 − x SnO ( x ∼ 0.5 ). Because no clear peaks originating from superstructures were observed, strontium deficiency is most likely to be randomly distributed. We also performed first-principles band-structure calculations on S r 3 − x SnO ( x = 0, 0.5 ) using two methods: full-potential linearized-augmented plane-wave plus local orbitals method and the Korringa-Kohn-Rostoker Green function method combined with the coherent potential approximation. We revealed that the Fermi energy of S r 3 − x SnO in case of x ∼ 0.5 is about 0.8 eV below the original Fermi energy of the stoichiometric Sr 3 SnO, where the mixing of the valence p and conduction d orbitals are considered to be small.

This contribution directly relates to the paper published by Wheeler in 1978 entitled ‘Why were there no fish remains at Star Carr?’. Star Carr is arguably the richest, most studied and re-interpreted Mesolithic site in Europe but the lack of fish remains has continued to vex scholars. Judging from other materials, the preservation conditions at the site in the late 1940s/early 1950s should have been good enough to permit the survival of fish remains, and particularly dentaries of the northern pike ( Esox lucius L., 1758) as found on other European sites of this age. The lack of evidence has therefore been attributed to a paucity of fish in the lake. However, new research has provided multiple lines of evidence, which not only demonstrate the presence of fish, but also provide evidence for the species present, data on how and where fish were being processed on site, and interpretations for the fishing methods that might have been used. This study demonstrates that an integrated approach using a range of methods at landscape, site and microscopic scales of analysis can elucidate such questions. In addition, it demonstrates that in future studies, even in cases where physical remains are lacking, forensic techniques hold significant potential.

This study presents the first stable isotopic and sclerochronological calibration of the bivalve Anomalocardia flexuosa (Linnaeus, 1767) in relation to environmental variables in a subtropical coastal area of southern Brazil. We investigate incremental shell growth patterns and δ18O and δ13C values of modern specimens collected alive from the Laguna Lagoonal System (LLS). Shells of Anomalocardia flexuosa are also one of the main biological components of pre-Columbian archaeological shell mounds and middens distributed along the Brazilian coastline. We therefore selected archaeological specimens from a local late Holocene shell mound (Cabecuda) to compare their stable carbon and oxygen isotope values with those of modern specimens. Shell growth increments, δ18O and δ13C values respond to a complex of environmental conditions, involving, for example, the effects of temperature and salinity. The isotopic information extracted from archaeological specimens from Cabecuda shell midden in the LLS indirectly indicates that environmental conditions during the late Holocene were different from present day. In particular, intra-shell δ18O and δ13C values of archaeological shells reveal a stronger marine influence at 3 ka cal BP, which is in contrast to the seasonal freshwater/seawater balance that currently prevails at the LLS.

Bis(tri-tert-butylphosphine)palladium-catalyzed arylation of ortho-sulfanyl aryl halides with sodium tetraarylborates proceeds smoothly without any additional bases in high yields, providing a reliable route to 2-sulfanylbiaryls. The conditions are applicable to aryl chloride and iodide as well as bromides. A variety of functional groups were tolerated. This arylation protocol offers a practical solution to overcome the poisoning behavior of aryl sulfides in such cross-coupling arylation. In addition, our strategy provides a short and efficient access to dibenzothiophenes in combination with a Pummerer-type cyclization.

The marine gastropod Conomurex fasciatus (Born 1778) is the main component of thousands of shell middens on the Farasan Islands in the southern Red Sea. The middens date from 6500 to 4500 cal BP and cover the period of increased aridification over the region. No general research on C. fasciatus has been carried out before and basic information about the species is mostly speculative. To test if C. fasciatus shells can be used as a recorder of climate variability, we collected living specimens from the Farasan Islands, in Saudi Arabia, over a 1.5 year period. This area receives almost no precipitation and sea surface salinity is extremely high (38–39 psu), and sea surface temperature (SST) ranges from +26.5 °C to +34.9 °C. Raman spectroscopy results on modern C. fasciatus shell samples show these specimens to be aragonitic. Ground fragments from archaeological C. fasciatus shells used for isotope analyses were also measured by Raman spectroscopy and shown to be well preserved against diagenetic alterations leading to aragonite to calcite transformation. Measured shell-edge δ18O values range from −0.5‰ to −1.7‰. Calculated modern shell edge temperatures from these δ18O values correlate with modern SST measured on site with an error of ±2.4 °C. Two different growth rates occurred in the shells of C. fasciatus. The measurement of growth increments in the lip part of adult specimens indicates a tide-related growth rate of ∼13 mm/year. Sequential δ18O data from juvenile parts of the shell indicates a faster growth rate of ∼90 mm/year. This growth rate and the correlation of δ18O with measured temperatures allows the use of C. fasciatus shell δ18O as a palaeoclimate proxy.

Records of past environmental conditions in shell carbonate are usually derived from compositional analysis (i.e. trace elements, stable oxygen, carbon, and nitrogen isotopes) performed along the direction of the shell’s growth and thus through time. However, compositional variations within isochronous parts of the shell can distort the environmental record and are difficult to assess without extensively mapping the whole shell. Here we apply Laser Induced Breakdown Spectroscopy (LIBS) to efficiently map the elemental change throughout the growth increments of three mollusc shells (Conomurex fasciatus, Ostrea edulis, Anomalocardia flexuosa). We employ an automated LIBS setup to map the Mg/Ca composition of whole shell sections with over 2,000 data points per hour. By assessing the spatial variability of Mg/Ca intensity ratios this method has the potential to mitigate distorted results while increasing the resolution of derived palaeoenvironmental information.

Oxides with perovskite-based structures have been known as essential materials for fascinating phenomena such as high-temperature and unconventional superconductivity. Discoveries of these oxide superconductors have driven the science community to vastly extend the concepts of strongly correlated electron systems. The base of these materials, the cubic perovskite oxides, $AB$O$_3$, also exhibit superconductivity with $T_{\mathrm{c}}$ of up to 30 K, as reported for Ba$_{0.6}$K$_{0.4}$BiO$_3$. Perovskite oxides have their counterparts, antiperovskite oxides $A_3B$O (or "$B$O$A_3$"), in which the position of metal and oxygen ions are reversed and therefore metallic $B$ ions take unusual negative valence states. However, no superconductivity has been reported among antiperovskite oxides. Here, we report the discovery of the first superconducting antiperovskite oxide Sr$_3$SnO with $T_{\mathrm{c}}$ of around 5 K. Sr$_3$SnO possesses Dirac points in its electronic structure, originating from the inversion of bands with different parities. Based on theoretical analysis, we propose possibility of topological odd-parity superconductivity analogous to the superfluid $^3$He-B, in moderately hole-doped Sr$_3$SnO, originating from unusual orbital texture on the Fermi surface. We envision that this discovery of a new class of oxide superconductor with the inverted valence configuration will stimulate the exploration of topological materials science based on a variety of antiperovskite oxides., Comment: 24 pages, 9 figures

Annual growth patterns in marine mollusc shells are valuable indicators of the condition of marine ecology through time. In archaeological contexts, the mollusc’s time of death (i.e. the last season of growth) is an indicator of human exploitation patterns throughout the year, enabling the reconstruction of when and how often gathering occurred as well as when sites were occupied. Both pieces of information, growth rate and season of death, are vital for understanding exploitation pressure(s) in the past, and building baselines for modern environmental policies that secure sustainable marine resources. Previously, these parameters have been determined by incremental growth-line or isotopic analyses, which are time consuming and often expensive techniques, thus restricting sample size and the overall robustness of palaeoecological interpretations.\ud \ud Here, we apply Laser Induced Breakdown Spectroscopy (LIBS) to produce elemental maps (Mg/Ca) with the potential to trace and display growth patterns quickly, and at a reduced cost. We further compare the elemental maps with the results obtained from incremental growth-line analysis to provide a structural context for the geochemical data, and demonstrate the utility of an integrated methodological approach.\ud \ud Our pilot study was undertaken on 12 European oysters (Ostrea edulis, Linnaeus, 1758) from the Late Mesolithic shell midden at Conors Island, Co. Sligo in the Republic of Ireland. Our LIBS analysis enabled us to accurately and quickly determine repeating growth patterns, which were often in agreement with the annual growth increments visible through the microscopic analysis. Based on this comparative dataset, including structural and geochemical patterns, the Late Mesolithic site of Conors Island had been occupied throughout the year. Moreover, our analyses highlight the applicability of LIBS to determine prehistoric seasonality practices as well as biological age and growth at an improved rate and reduced cost than was previously achievable.