Variations in the solar spectral irradiance (SSI) with the 11-year sunspot cycle have been shown to have a significant impact on temperatures and the mixing ratios of atmospheric constituents in the stratosphere and mesosphere. Uncertainties in modelling the effects of SSI variations arise from uncertainties in the empirical models reconstructing the prescribed SSI data set as well as from uncertainties in the chemistry–climate model (CCM) formulation. In this study CCM simulations with the ECHAM/MESSy Atmospheric Chemistry (EMAC) model and the Community Earth System Model 1 (CESM1)–Whole Atmosphere Chemistry Climate Model (WACCM) have been performed to quantify the uncertainties of the solar responses in chemistry and dynamics that are due to the usage of five different SSI data sets or the two CCMs. We apply a two-way analysis of variance (ANOVA) to separate the influence of the SSI data sets and the CCMs on the variability of the solar response in shortwave heating rates, temperature, and ozone. The solar response is derived from climatological differences of time slice simulations prescribing SSI for the solar maximum in 1989 and near the solar minimum in 1994. The SSI values for the solar maximum of each SSI data set are created by adding the SSI differences between November 1994 and November 1989 to a common SSI reference spectrum for near-solar-minimum conditions based on ATLAS-3 (Atmospheric Laboratory of Applications and Science-3). The ANOVA identifies the SSI data set with the strongest influence on the variability of the solar response in shortwave heating rates in the upper mesosphere and in the upper stratosphere–lower mesosphere. The strongest influence on the variability of the solar response in ozone and temperature is identified in the upper stratosphere–lower mesosphere. However, in the region of the largest ozone mixing ratio, in the stratosphere from 50 to 10 hPa, the SSI data sets do not contribute much to the variability of the solar response when the Spectral And Total Irradiance REconstructions-T (SATIRE-T) SSI data set is omitted. The largest influence of the CCMs on variability of the solar responses can be identified in the upper mesosphere. The solar response in the lower stratosphere also depends on the CCM used, especially in the tropics and northern hemispheric subtropics and mid-latitudes, where the model dynamics modulate the solar responses. Apart from the upper mesosphere, there are also regions where the largest fraction of the variability of the solar response is explained by randomness, especially for the solar response in temperature.

The Eocene/Oligocene Transition represents a period of profound changes in diatom productivity and evolutionary history within the Cenozoic era. Unraveling how these changes correlate with climatic shifts during this transition is crucial for understanding the potential role of diatoms in the cooling trends observed at the Eocene/Oligocene boundary (∼ 33.9 Ma). Current research predominantly relies on bulk opal accumulation measurements to assess productivity dynamics, which fails to distinguish the contribution of different biosiliceous (e.g., diatom versus radiolarian) plankton to total biogenic silica productivity. Furthermore, despite the fundamental role of community composition and diversity in diatom productivity and carbon sequestration, these factors are often not incorporated in existing studies focusing on the late Paleogene diatom productivity. The main objective of our work is to explore the potential roles of diatom communities in the Late Eocene climatic changes by focusing on diatom- and radiolarian-specific productivity across multiple Southern Ocean sites, rather than bulk opal measurements, and by incorporating total diatom abundance into the analysis of diatom diversity evolution throughout the Eocene/Oligocene transition. By quantifying diatom and radiolarian abundances across four Southern Ocean sites in the Atlantic and Indian Ocean sectors, and analyzing diatom productivity through recent reconstructions of diatom diversity from approximately 40–30 Ma interval, our findings reveal a significant increase in diatom abundance coupled with notable shifts in community diversity. These changes suggest a potential ecological shift, likely associated with the development of stronger circum-Antarctic currents in the Late Eocene. Such shifts could have influenced the efficiency of the biological carbon pump by enhancing organic carbon export to the deep ocean and thus potentially contributing to reduced atmospheric CO2 levels. While our findings indicate that the expansion of diatoms may have been a part of the mechanisms underlying the Late Eocene cooling, they also highlight the importance of integrating diatom diversity and community evolution into diatom productivity research. Furthermore, our results offer valuable insights into the complex relationship between diatom abundance and diversity in the geological record, reflecting the intricate interplay of environmental and climatic factors.

The climate of the western coast of South America is controlled by large climate systems known as the Intertropical Convergence Zone (ITCZ), the Subtropical Pacific High (SPH) and the Southern Hemisphere Westerly wind (SWW) belt. While the large-scale evolution of the SWW belt and the location of the ITCZ are well constrained, the interaction between these two climate features is not well understood as a high resolution spatial and temporal reconstruction of the SWW belt is still lacking. Here, we use the hydrogen isotope ratios of leaf-wax n-alkanes in marine sediments between 33 and 36° S offshore Chile to reconstruct past hydrological regimes and the evolution of the SWW belt since the Last Glacial Maximum (LGM, ca. 20 000 cal yr BP). Our results reveal distinct dry and wet phases caused by the past latitudinal migration of the SWW belt – with wetter intervals associated with a northerly SWW belt and drier intervals associated with a southerly SWW belt. Our findings imply a northward position of the SWW belt during the LGM, followed by a southward migration of the SWW belt during the deglaciation period. This shift southward was briefly interrupted during the Antarctic Cold Reversal (ca. 14 700 to 13 000 cal yr BP). The SWW belt reached its southernmost latitudes during the early Holocene. At ca. 7500 yr BP, a displacement northward of the SWW belt was detected at latitudes south of 36° S and, during the last 5500 years, the SWW belt progressively migrated northward. From 17 000 to 11 500 cal yr BP, these migrations appear to be tied to atmospheric circulation regimes resulting from large changes in the interhemispheric temperature gradient and subsequent changes in the Hadley cell circulation, while the migrations in the Holocene (11 500 cal yr BP to present) appear to be predominantly controlled by insolation and atmospheric circulation regimes resembling those of El Niño-Southern Oscillation events.

Climate records for the Last Glacial Maximum (LGM) in Southern Africa are scarce, and the glaciation of the highest summits has been controversially discussed. Geomorphological features on south-facing slopes at six sites in the high Drakensberg Escarpment of Eastern Lesotho were postulated as moraines indicating marginally short-lived and site-specific glaciation during the LGM. However, previous discussions on precipitation amounts limiting or inhibiting glaciers are challenged by more recent studies suggesting increased humidity and water availability during the LGM. One postulated moraine site at the Tsatsa-La-Mangaung mountain range near Sani Pass was revisited to address the contradictory results. Drone-based remote sensing and field surveys suggest a different formation process of the moraine-like slightly bent landform considering lithological variance and dike system occurrence, which is connected not to glacial but to gravitational and erosional processes. The formation of landforms interpreted as moraines in the high-altitude regions of Lesotho and their paleoclimatic implications for the LGM require reevaluation.

The high consumption of fossil fuels has contributed significantly to environmental pollution and climate change. One strategy to address these challenges is utilizing renewable energy sources, such as hydrogen. This research marks the first attempt to synthesize perovskite-type LaCo0.2Mn0.8O3 nanoceramics using green and sol–gel methods and to evaluate their performance as potential materials for electrochemical hydrogen storage applications. The orthorhombic structure of the samples was identified from XRD patterns. The average crystallite size of LaCo0.2Mn0.8O3 nanoceramics prepared using green and sol–gel methods was calculated using the Debye–Scherrer equation and found to be 31 and 23 nm, respectively. The morphological studies confirmed the nanoscale formation of LaCo0.2Mn0.8O3 nanoceramics with an approximately spherical shape in both methods. The BET analysis revealed that the samples showed a type II isotherm. The electrochemical properties of the samples studies using cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), and charge–discharge chronopotentiometry (CP) techniques. The specific capacitance value of LaCo0.2Mn0.8O3 nanoceramics synthesized using the sol–gel (1164F/g) method is higher than the green (564F/g) method, which indicates its superior energy storage capability. Additionally, the discharge capacity of LaCo0.2Mn0.8O3 nanoceramics prepared using the sol–gel method (1008 mAh/g) is significantly higher than that of the green method (387 mAh/g) in 3 M KOH electrolyte solution.

We present version 1.0 of the Chemical Mechanism Integrator (Cminor), a fully modularized modern Fortran software package for the computational simulation of skeletal and detailed chemical kinetic systems derived from atmospheric and combustion chemistry. Cminor aims for the efficient simulation of complex chemical mechanisms by using various mathematical techniques. These are tailored to systems of ordinary differential equations (ODEs), having the specific structure arising from chemical reaction systems. Additionally, a high-speed mechanism parser allows the user to interchange reactions or their parameters in an ASCII format text file and immediately start a new simulation without recompiling, enabling fast and numerous simulations. Cminor's solver technique is based on Rosenbrock methods. Different measures of local errors and an analytical Jacobian matrix approach are implemented, where efficiency is obtained by exploiting the sparsity structure of the Jacobian.

Cminor can be run in one of three configurations:

A box-model framework for either pure gas-phase mechanisms or a multi-modal aerosol distribution dissolved in mono-dispersed cloud droplets.

A rising adiabatic parcel, in which the activation of multi-modal aerosols is represented by solving the droplet condensation equation.

A constant volume environment, where thermodynamic properties are evaluated by polynomial functions of temperature according to the standards of the Chemkin thermodynamic data base.

The software package is evaluated by applying seven different chemical mechanisms. Three of them are from the field of air-quality modeling and three are from the area of combustion kinetics, ranging from 7 species and 10 reactions to 10 196 species and 23 098 reactions. The last mechanism describes sulfur accumulation in clouds, which is tested along with a rising parcel and condensating cloud droplets.

A retrieval of total column water vapour (TCWV) from the new daytime, clear-sky near-infrared (NIR) measurements of the Flexible Combined Imager (FCI) onboard the geostationary satellite Meteosat Third Generation Imager (MTG-I, Meteosat-12) is presented. The retrieval algorithm is based on the differential absorption technique, relating TCWV amounts to the radiance ratio of a non-absorbing band at 0.865 µm and a nearby water vapour (WV) absorbing band at 0.914 µm. The sensitivity of the band ratio to WV amount increases towards the surface which means that the whole atmospheric column down to the boundary-layer moisture variability can be observed well.

The retrieval framework is based on an optimal estimation (OE) method, providing pixel-based uncertainty estimates. It builds on well-established algorithms for other passive imagers with similar spectral band settings. Transferring knowledge gained in their development onto FCI required new approaches. The absence of additional, adjacent window bands to estimate the surface reflectance within FCI's absorbing channel is mitigated using a principal component regression (PCR) from the bands at 0.51, 0.64, 0.865, 1.61, and 2.25 µm.

We utilize synergistic observations from Sentinel-3 Ocean and Land Colour Instrument (OLCI) and Sea and Land Surface Temperature Radiometer (SLSTR) to generate “FCI-like” measurements. OLCI bands were complemented with SLSTR bands, enabling evaluation of the retrieval's robustness and global performance of the PCR. Furthermore, this enabled algorithm testing under realistic conditions using well-characterized data, at a time when a long-term, fully calibrated FCI Level 1c dataset was not available. We built a forward model for two FCI equivalent OLCI bands at 0.865 and 0.9 µm. A long-term validation of OLCI against a single atmospheric radiation measurement (ARM) reference site without the PCR resulted in a bias of 1.85 kg m−2, centred root-mean-square deviation (cRMSD) of 1.26 kg m−2, and a Pearson correlation coefficient (r) of 0.995.

A first verification of the OLCI/SLSTR “FCI-like” TCWV against well-established ground-based TCWV products concludes with a wet bias between 0.33–2.84 kg m−2, a cRMSD between 1.46–2.21 kg m−2, and r between 0.98–0.99. In this set of comparisons, only land pixels were considered. Furthermore, a dataset of FCI Level 1c observations with a preliminary calibration was processed. The TCWV processed for these FCI measurements aligns well with reanalysis TCWV and collocated OLCI/SLSTR TCWV but shows a dry bias. A more rigorous validation and assessment will be done once a longer record of FCI data is available.

TCWV observations derived from geostationary satellite measurements enhance monitoring of WV distributions and associated meteorological phenomena from synoptic scales down to local scales. Such observations are of special interest for the advancement of nowcasting techniques and numerical weather prediction (NWP) accuracy as well as process-studies.

Population growth and agricultural expansion cause major changes in land use and land cover (LULC) in Ethiopia. Cultivated lands are mostly expanding without land suitability evaluation. Consequently, crop yields are not increasing as expected. This is particularly the case in the highland catchments draining toward Lake Tana, where severe consequences such as deforestation and the degradation of soil and land can be observed. In this study, the impacts of long-term LULC dynamics on the land suitability potential for selected major crops in three sub-catchments of Lake Tana, Ethiopia (Gilgelabay, Gumara and Ribb), were evaluated. Time series of Landsat images from three periods (1988, 1998, and 2017) were classified. Land suitability was analyzed via a multi criteria approach based on spatial input data such as elevation, soil, and slope maps. The overall accuracy for all LULC classifications was good to very good (89.7% to 91.6%). Five major LULC classes were distinguished: agriculture, forest, shrub/bushland, grassland, and water. In all three catchments, the results revealed that agricultural land was the dominant land cover that expanded at the expense of the other land cover types to 80%-90% in all catchments in 2017. The rate of change in agricultural land in the Gilgelabay catchment (4041.3 ha/yr) was greater than that in the Gumara (1374.5 ha/yr) and Ribb (1362.3 ha/yr) catchments. This is possibly due to the availability of other LULC classes. The natural vegetation of Gilgelabay, Gumara, and Ribb has decreased by 16.0%, 10.5%, and 1.1%, respectively, over the past three decades. However, the present LULC change trends are unsustainable, and any remaining natural vegetation should be maintained. The results from the land suitability analysis revealed that the land suitability for teff, corn, and rice is likely to change with climate change in the future. To ensure sustainable land use management, modifying land use on the basis of land suitability should be preferred over traditional practices to improve crop production. This can be achieved in close collaboration with all stakeholders, including local communities, the government, and NGOs.

Ferroelectric devices such as capacitors, tunnel junctions and field-effect transistors rely on the reversible switching of polarisation under an electric field, which strongly depends on the screening charges at the interfaces. Despite the crucial role of charge trapping and detrapping on the performance of ferroelectric devices, current understanding relies heavily on electrical measurements of the whole device and/or local analysis of the atomic polarisation and structure. Here, we show how the internal electric fields can be measured within a ferroelectric Hf0.5Zr0.5O2 /Al2O3 tunnel junction using in situ electrical biasing electron holography. The charge densities at internal interfaces are quantitatively determined. Moreover, the polarisation switching of the ferroelectric film is mapped as the voltage gradually increases to the coercive voltage, revealing that switching occurs via both the nucleation and lateral growth of domains. This approach, complementary to existing techniques, opens new avenues for engineering the interfaces in ferroelectric devices.

Vertical greening systems are a promising solution to the increasing demand for urban green spaces, improving environmental quality and addressing biodiversity loss. This study facilitates the development microbially greened algal biofilm facades, which offer a low maintenance vertical green space. The study focuses on concrete as a widely used building material and explores how physical surface characteristics impact its bioreceptive properties. Concrete samples, produced from the same mix but differing in surface structure, were subjected to a laboratory weathering experiment to assess their bioreceptivity. A novel inoculation method was employed, involving a single initial inoculation with either alga ( Jaagichlorella sp.) alone, or a model biofilm consisting of a combination of the alga ( Jaagichlorella sp.) with a fungus ( Knufia petricola ). The samples underwent four months of weathering in a dynamic laboratory setup irrigated with deionized water to observe subaerial biofilm attachment and growth. The formation of subaerial biofilms was monitored with high resolution surface imaging, colorimetric measurements and Imaging Pulse Amplitude Modulated Fluorometry (Imaging PAM-F), with Imaging PAM-F proving the most effective. Statistical analysis revealed that by impacting surface pH value and water retention capability, surface structures significantly influence microbial growth and that the concrete’s bioreceptivity can be influenced through thoughtful design of the materials surface. The inoculation of algae combined with a fungus facilitated the formation of a stable subaerial biofilm, enabling algae to colonize a surface structure that it could not colonize alone. This finding highlights the importance of modelling synergistic interactions present in natural biofilms.

An evolving body of research generally referred to as visual politics has brought the heavy research focus on linguistic modalities of political communication closer to parity with visual emphasis. The study reported here transcends this schism by joining momentum toward multimodality as an ontological departure point for research. We expanded an existing visual instrument into a multimodal one and provided evidence that it reliably captures character framing of political candidates (stateliness, compassion, mass appeal, ordinariness, and sure loser) in German, Polish, and United States commercial online news. We focused on election coverage in these countries because they represent three distinct political and media systems (democratic-corporatist, polarized-pluralist, and hybrid) of the Global North. The quantitative content analysis sample we used spans 2,688 online news stories with seven political candidates identified in 6,560 cases across six modalities (still images, moving images, frozen video images, text, audio, and superimposed text). We found support for the hypothesis that political and media system latencies affect how news media frame the character traits of political candidates in both visual and linguistic modalities. Specifically, the competitive tendencies of majoritarian democracies manifested more clearly as candidate-centered, simplistic, and polarizing character framing in US media content than in journalistic output of multiparty consensus democracies. For example, US news media were more consistent in their portrayal of election winners and losers than German and Polish news media, emphasizing stateliness, compassion, and ordinariness in the winner while unambiguously assigning the negative sure loser frame to the election loser.

Metazoan histone mRNAs are a unique class of mRNAs that lack the poly(A) tail present in all other eukaryotic transcripts. Instead, they end in a conserved stem-loop (SL) structure, necessitating a decay mechanism that is distinct from deadenylation-initiated degradation. Here, combining structural and functional approaches, we elucidate molecular mechanisms of initiation of histone mRNA decay. At the end of S-phase, the RNA helicase UPF1, the exoribonuclease 3’hExo and stem-loop binding protein SLBP all contribute to histone mRNA degradation, although how they are mechanistically coupled remained unknown. The cryoEM structure of an UPF1:SL RNA complex, presented here, shows that binding of UPF1 partially melts the RNA stem in the absence of ATP, harnessing the free energy derived from RNA-binding to unwind RNA. This melting event primes the SL-RNA for decay by 3’hExo. Using biochemical and cellular analyses, we demonstrate that SLBP directly engages the UPF1 helicase core to attenuate its unwinding activity and prevent premature degradation. Activation of UPF1 at a later stage promotes SL-RNA decay. We provide direct evidence that UPF1, SLBP and 3’hExo form a degradosome-like assembly that functionally couples SL unwinding and degradation, highlighting a dynamic and intricate network of UPF1-centric interactions that orchestrates timely histone mRNA decay.

A highly efficient and atom-economical method for the C–H trifluoromethylation of (hetero)arenes and complex biomolecules has been developed using a substoichiometric amount of the stable tetrakis(trifluoromethyl)cuprate(iii) salt. Upon violet-light irradiation in the presence of an oxidant, all four CF3 groups are sequentially converted into trifluoromethyl radicals, enabling high-yielding transformations under mild conditions. The protocol exhibits excellent functional group tolerance and is applicable to the late-stage trifluoromethylation of pharmaceuticals, amino acids, and nucleosides. Mechanistic studies support a photoinitiated radical pathway and reveal the full utilization of the Cu(iii) species. The results presented advance the use of copper-mediated strategies for the sustainable incorporation of fluorine into complex molecules.

The reaction of AgCN with two equivalents of tris(pentafluorophenyl)borane (BCF) in CH2Cl2 or ortho-difluorobenzene (oDFB) provides a straightforward access to (solvated) Ag+ salts of the weakly coordinating cyanide-bridged anion [µ-(CN)(BCF)2]− (suggested abbreviation [BCNB]). Reacting Ag[BCNB] with Ni(CO)4 yields the first structurally characterized complex in which Ni(CO)4 acts as a ligand towards a transition metal ion proving the extremely low basicity of the anion.

The installation of a boron unit into bioactive scaffolds continues to unlock novel modes of molecular recognition in drug discovery. As such, de novo strategies to access 3D boron-containing frameworks, that modulate the intrinsic reactivity at boron, are being intensively pursued. Herein, we report a visible light-mediated energy transfer (EnT) catalysis strategy that enables the [2 + 2] cycloaddition of boron-containing heterocycles to construct 3D frameworks with high structural complexity. Leveraging both inter- and intramolecular cycloadditions, a suite of angularly fused boron heterocycles was accessed, offering enhanced steric shielding and modular handles for additional interactions. A boron deletion strategy permits the synthesis of benzofuran scaffolds, otherwise inaccessible via direct EnT. Crucially, the resulting 3D architectures mimic structural motifs found in the potent β-lactamase inhibitor Xeruborbactam. The biological relevance of these frameworks was validated by NMR titration, pKa analysis, and co-crystallisation with serine β-lactamase CTX-M-14, revealing enantiospecific binding and a well-defined hydrogen bonding network. These results establish a versatile platform for the synthesis of functionalised boron heterocycles with direct translational potential in medicinal chemistry.

Contextualizing the lag between detection and publication of invasive species records is critical for management and communication. Using a literature review of records spanning 1963–2023 and complementary snapshot monitoring data (2012–2016), we quantify the lag time of reporting new records by researchers and illustrate the importance of timely and more reliable tracking of Ceratium spread, a genus of bloom-forming dinoflagellates with phytosanitary and ecological impacts. Our literature review indicates that records of C. furcoides and C. hirundinella (in South America) show considerable publication delays ( C. furcoides 4.3 ± 2.6 years and C. hirundinella 4.9 ± 3.9 years), limiting early control and informed water management decisions. Our mixed-effects model revealed that publication delays have significantly decreased over time, but remain longer in Brazilian records and in reservoir and river environments. From monitoring data, C. furcoides was found at 72 sites, 53 of which remain unpublished to date, spanning urban, peri-urban, and rural water bodies in São Paulo, South America’s most populous state. The species was absent from 225 sites, often associated with slightly higher water quality and preserved vegetation. More transparent and timely reporting, including absence data, is essential to enable risk modeling and preventive planning in a changing world. Once published, such data can offer valuable insights into species distributions, enabling reconstruction of invasion routes, estimation of spread rates, and identification of potential lag phases.

Sarcocystis calchasi is the causative agent of Pigeon Protozoal Encephalitis, a neurological disease in pigeons. The biphasic disease is characterized by neurological signs in the chronic phase. Parasite stages are generally not associated with inflammatory brain lesions and the parasite has been suggested to modulate the host’s immune system. To test this hypothesis, pigeons experimentally infected with S. calchasi were T-cell immunosuppressed beginning from 14 days post infection (dpi) until the end of the experiment (59/60 dpi) and compared with immunocompetent animals. When scored histologically (sum encephalitis score consisting of lympho-histiocytic perivascular cuffs, lymphocytic encephalitis and gliosis), encephalitis was markedly less pronounced in immunosuppressed pigeons than in immunocompetent animals (6.8 ± 4.4 s.d. versus 11.2 ± 3.0 s.d.). Thus, the alleviation of the disease by immunosuppression supports the hypothesis of an immune-mediated mechanism rather than direct damage by the pathogen. Results from a second infection trial, where the effect of immunosuppression only during early (12–20 dpi) or late phase (30 dpi – end of experiment) was compared, did not show significant differences between both groups and suggest that immunomodulation is triggered during the early stage of parasite development by sporozoites and/or more likely merozoites.

Highly resolved vibrational spectra of the mononuclear Fe(II) spin-crossover complex [Fe(bpz)2(bipy)]; (bpz = dihydrobis(pyrazolyl)borate) and its dinuclear counterpart [{Fe(bpz)2}2μ–(ac(bipy)2)] (ac(bipy)2 = bridging ligand) are obtained by temperature-dependent far-infrared (FIR) spectroscopic measurements and assigned with the help of density functional theory (DFT) calculations. The experimental data confirm the high-spin (HS) state of the complexes at high temperature (≈ 200 K) and the low-spin (LS) state at 5 K. In the dimer, enhancement of otherwise absent vibrational modes at 335 cm–1 and 504 cm–1 around T1/2 reflects the presence of a mixed-spin HS-LS state during the course of the spin transition between HS-HS and LS-LS. The metastable HS state of the dinuclear complex resulting from light irradiation (532 nm) at 10 K results from a direct spin-state transition from LS-LS to HS-HS.

Ailios Aristeides saw himself as steeped in the tradition of Greek paideia, and his choice and representation of divinities largely reflect the same interest in classical ‘Greekness’ which pervades his works as a whole. One exception stands out: the ‘Egyptian’ gods Isis and, more prominently, Sarapis. The fact that Aristeides worships these gods is not in itself surprising, given their popularity in the second century CE. It does, however, raise the question of how Aristeides integrates them into a pantheon which he understands as rooted in a tradition without them. This article examines how Aristeides constructs and incorporates the ‘foreignness’ of Sarapis in the Hieroi Logoiand Hymn to Sarapisand what he gains from the god’s connection to Egypt. Aristeides, it is argued, balances Egyptian-connotated and Greek testimony to raise Sarapis to the status of a universal god and to make him comparable and compatible with a traditional picture of Greek divinity without assimilating him. Sarapis retains just enough Egyptian colouring to distinguish him from the other gods and lend Aristeides’ writings and religiosity a touch of ‘Egyptianness’. By assuming the compatibility of Egyptian and Greek religious traditions instead of either completely Hellenising or exoticising Sarapis, Aristides can draw on the authority of both to enhance, via Sarapis, his own claims to extra-institutional religious authority and exceptional nearness to the divine. His enterprise is facilitated by the importance of the written word as the basis of imperial Greek intellectual identity. Textuality gives Aristeides a way to bridge classical tradition with post-classical cultic reality: classical Greek texts supply him with a tradition of writing about Egypt into which he can fit the (for him) Egyptian god Sarapis, and the association of Egypt with expressly religious writings, with abundant ‘sacred texts’, both complements the very limited role of sacred texts in traditional Greek literature and religion and appeals to the value and authority which pepaideumenoiattach to the written word.