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Arctic haze is a seasonal phenomenon with high concentrations of accumulation-mode aerosols occurring in the Arctic in winter and early spring. Chemistry transport models and climate chemistry models struggle to reproduce this phenomenon, and this has recently prompted changes in aerosol removal schemes to remedy the modeling problems. In this paper, we show that shortcomings in current emission data sets are at least as important. We perform a 3 yr model simulation of black carbon (BC) with the Lagrangian particle dispersion model FLEXPART. The model is driven with a new emission data set (\"ECLIPSE emissions\") which includes emissions from gas flaring. While gas flaring is estimated to contribute less than 3% of global BC emissions in this data set, flaring dominates the estimated BC emissions in the Arctic (north of 66° N). Putting these emissions into our model, we find that flaring contributes 42% to the annual mean BC surface concentrations in the Arctic. In March, flaring even accounts for 52% of all Arctic BC near the surface. Most of the flaring BC remains close to the surface in the Arctic, so that the flaring contribution to BC in the middle and upper troposphere is small. Another important factor determining simulated BC concentrations is the seasonal variation of BC emissions from residential combustion (often also called domestic combustion, which is used synonymously in this paper). We have calculated daily residential combustion emissions using the heating degree day (HDD) concept based on ambient air temperature and compare results from model simulations using emissions with daily, monthly and annual time resolution. In January, the Arctic-mean surface concentrations of BC due to residential combustion emissions are 150% higher when using daily emissions than when using annually constant emissions. While there are concentration reductions in summer, they are smaller than the winter increases, leading to a systematic increase of annual mean Arctic BC surface concentrations due to residential combustion by 68% when using daily emissions. A large part (93%) of this systematic increase can be captured also when using monthly emissions; the increase is compensated by a decreased BC burden at lower latitudes. In a comparison with BC measurements at six Arctic stations, we find that using daily-varying residential combustion emissions and introducing gas flaring emissions leads to large improvements of the simulated Arctic BC, both in terms of mean concentration levels and simulated seasonality. Case studies based on BC and carbon monoxide (CO) measurements from the Zeppelin observatory appear to confirm flaring as an important BC source that can produce pollution plumes in the Arctic with a high BC / CO enhancement ratio, as expected for this source type. BC measurements taken during a research ship cruise in the White, Barents and Kara seas north of the region with strong flaring emissions reveal very high concentrations of the order of 200–400 ng m−3. The model underestimates these concentrations substantially, which indicates that the flaring emissions (and probably also other emissions in northern Siberia) are rather under- than overestimated in our emission data set. Our results suggest that it may not be \"vertical transport that is too strong or scavenging rates that are too low\" and \"opposite biases in these processes\" in the Arctic and elsewhere in current aerosol models, as suggested in a recent review article (Bond et al., Bounding the role of black carbon in the climate system: a scientific assessment, J. Geophys. Res., 2013), but missing emission sources and lacking time resolution of the emission data that are causing opposite model biases in simulated BC concentrations in the Arctic and in the mid-latitudes.

The basalts of the 2021 Fagradalsfjall eruption were the first erupted on the Reykjanes Peninsula in 781 years and offer a unique opportunity to determine the composition of the mantle underlying Iceland, in particular its oxygen isotope composition (δ 18 O values). The basalts show compositional variations in Zr/Y, Nb/Zr and Nb/Y values that span roughly half of the previously described range for Icelandic basaltic magmas and signal involvement of Icelandic plume (OIB) and Enriched Mid-Ocean Ridge Basalt (EMORB) in magma genesis. Here we show that Fagradalsfjall δ 18 O values are invariable (mean δ 18 O = 5.4 ± 0.3‰ 2 SD, N  = 47) and indistinguishable from “normal” upper mantle, in contrast to significantly lower δ 18 O values reported for erupted materials elsewhere in Iceland (e.g., the 2014–2015 eruption at Holuhraun, Central Iceland). Thus, despite differing trace element characteristics, the melts that supplied the Fagradalsfjall eruption show no evidence for 18 O-depleted mantle or interaction with low-δ 18 O crust and may therefore represent a useful mantle reference value in this part of the Icelandic plume system. The 2021 eruption in the Reykjanes Peninsula of Iceland was the first in 800 years and was supplied by melts from diverse mantle source domains with near-identical oxygen isotope ratios, providing a unique insight into the Icelandic mantle plume.

Well-connected quasicrystals Quasicrystals are unique materials combining long-range order with 'impossible' packing symmetries like fivefold rotation, forbidden in periodic structures. Until now, they have been found only in specific systems such as intermetallic compounds, block copolymers, or colloidal particles under the action of a laser standing-wave pattern. Now Talapin et al . have self-assembled colloidal nanoparticles into aperiodic quasicrystalline lattices by carefully tailoring their sizes and using a novel packing motif. They can obtain quasicrystals with nanoparticles made of several different combinations of materials, pointing to the fact that only sphere packing and simple inter-particle potentials are important for their formation, and not specific interactions between the components These quasicrystals can also connect to the ordinary (crystalline) world through a thin 'wetting' layer with structures resembling the classic Archimedean tiling pattern. Quasicrystals are ordered structures that lack any translational symmetry, challenging the classic conception of ordered solids as periodic structures. So far, they have been reported in certain systems and can, for example, form from intermetallic compounds and organic dendrimers. Here it is shown that colloidal inorganic nanoparticles from several materials can self-assemble into binary aperiodic superlattices with quasicrystalline order. The discovery of quasicrystals in 1984 changed our view of ordered solids as periodic structures 1 , 2 and introduced new long-range-ordered phases lacking any translational symmetry 3 , 4 , 5 . Quasicrystals permit symmetry operations forbidden in classical crystallography, for example five-, eight-, ten- and 12-fold rotations, yet have sharp diffraction peaks. Intermetallic compounds have been observed to form both metastable and energetically stabilized quasicrystals 1 , 3 , 5 ; quasicrystalline order has also been reported for the tantalum telluride phase with an approximate Ta 1.6 Te composition 6 . Later, quasicrystals were discovered in soft matter, namely supramolecular structures of organic dendrimers 7 and tri-block copolymers 8 , and micrometre-sized colloidal spheres have been arranged into quasicrystalline arrays by using intense laser beams that create quasi-periodic optical standing-wave patterns 9 . Here we show that colloidal inorganic nanoparticles can self-assemble into binary aperiodic superlattices. We observe formation of assemblies with dodecagonal quasicrystalline order in different binary nanoparticle systems: 13.4-nm Fe 2 O 3 and 5-nm Au nanocrystals, 12.6-nm Fe 3 O 4 and 4.7-nm Au nanocrystals, and 9-nm PbS and 3-nm Pd nanocrystals. Such compositional flexibility indicates that the formation of quasicrystalline nanoparticle assemblies does not require a unique combination of interparticle interactions, but is a general sphere-packing phenomenon governed by the entropy and simple interparticle potentials. We also find that dodecagonal quasicrystalline superlattices can form low-defect interfaces with ordinary crystalline binary superlattices, using fragments of (3 3 .4 2 ) Archimedean tiling as the ‘wetting layer’ between the periodic and aperiodic phases.

A one-stop guide for the theories, applications, and statistical methodologies essential to operational risk Providing a complete overview of operational risk modeling and relevant insurance analytics, Fundamental Aspects of Operational Risk and Insurance Analytics: A Handbook of Operational Risk offers a systematic approach that covers the wide range of topics in this area. Written by a team of leading experts in the field, the handbook presents detailed coverage of the theories, applications, and models inherent in any discussion of the fundamentals of operational risk, with a primary focus on Basel II/III regulation, modeling dependence, estimation of risk models, and modeling the data elements. Fundamental Aspects of Operational Risk and Insurance Analytics: A Handbook of Operational Risk begins with coverage on the four data elements used in operational risk framework as well as processing risk taxonomy. The book then goes further in-depth into the key topics in operational risk measurement and insurance, for example diverse methods to estimate frequency and severity models. Finally, the book ends with sections on specific topics, such as scenario analysis; multifactor modeling; and dependence modeling. A unique companion with Advances in Heavy Tailed Risk Modeling: A Handbook of Operational Risk, the handbook also features: * Discussions on internal loss data and key risk indicators, which are both fundamental for developing a risk-sensitive framework * Guidelines for how operational risk can be inserted into a firm's strategic decisions * A model for stress tests of operational risk under the United States Comprehensive Capital Analysis and Review (CCAR) program A valuable reference for financial engineers, quantitative analysts, risk managers, and large-scale consultancy groups advising banks on their internal systems, the handbook is also useful for academics teaching postgraduate courses on the methodology of operational risk.

Nanoparticle self-assembly The assembly of nanoparticles of two different materials into a binary nanoparticle superlattice is a promising way of synthesizing a large variety of materials (metamaterials) with precisely controlled chemical composition and tight placement of the components. In theory only a few stable binary superlattice structures can assemble from hard spheres, potentially limiting this approach. But all is not lost because at the nanometre scale there are additional forces (electrostatic, van der Waals and dipolar) that can stabilize binary nanoparticulate structures. Shevchenko et al . now report the synthesis of a dozen novel structures from various combinations of metal, semiconductor, magnetic and dielectric nanoparticles. This demonstrates the potential of self-assembly in designing families of novel materials and metamaterials with programmable physical and chemical properties. Assembly of small building blocks such as atoms, molecules and nanoparticles into macroscopic structures—that is, ‘bottom up’ assembly—is a theme that runs through chemistry, biology and material science. Bacteria 1 , macromolecules 2 and nanoparticles 3 can self-assemble, generating ordered structures with a precision that challenges current lithographic techniques. The assembly of nanoparticles of two different materials into a binary nanoparticle superlattice (BNSL) 3 , 4 , 5 , 6 , 7 can provide a general and inexpensive path to a large variety of materials (metamaterials) with precisely controlled chemical composition and tight placement of the components. Maximization of the nanoparticle packing density has been proposed as the driving force for BNSL formation 3 , 8 , 9 , and only a few BNSL structures have been predicted to be thermodynamically stable. Recently, colloidal crystals with micrometre-scale lattice spacings have been grown from oppositely charged polymethyl methacrylate spheres 10 , 11 . Here we demonstrate formation of more than 15 different BNSL structures, using combinations of semiconducting, metallic and magnetic nanoparticle building blocks. At least ten of these colloidal crystalline structures have not been reported previously. We demonstrate that electrical charges on sterically stabilized nanoparticles determine BNSL stoichiometry; additional contributions from entropic, van der Waals, steric and dipolar forces stabilize the variety of BNSL structures.

The review addresses methods for the introduction of hydrogen isotopes into organic compounds, which are then used as labeled building blocks in the synthesis of biologically active products. Hydrogen isotopes are introduced by either isotope exchange or chemical reactions. If a carbonyl group is present in the precursor of the biologically active compound, deuterium can be introduced both through isotope exchange and via the reduction of the ketone group. Labeled reagents such as [ 3 H]methyl nosylate are also used to obtain labeled oligonucleotides. The introduction of hydrogen isotopes into estrone is performed using isotope exchange both in the solid state and in solution (D 2 O, CF 3 COOD). The replacement of the iodine atom with deuterium gives labeled analogs of xanthine, steroids, adamantane, carbohydrates, and other compounds. In some cases, to activate deuteration, deuterated silanes were synthesized and catalytic systems such as AgCO 3 /PPh 3 /K 2 CO 3 , Rh nanoparticles, and Pt II -based catalysts were used. Issues related to hydrogen spillover are discussed in the context of solid-phase isotope exchange.

Despite relatively good knowledge of the biogeochemistry of Siberian thermokarst lakes during summer base flow, their seasonal dynamics remains almost unexplored. This work describes the chemical composition of ~130 thermokarst lakes ranging in size from a few m2 to several km2, located in the discontinuous permafrost zone. Lakes were sampled during spring flood, just after the ice break (early June), the end of summer (August), the beginning of ice formation (October) and during the full freezing season in winter (February). The lakes larger than 1000 m2 did not exhibit any statistically significant control of the lake size on dissolved organic carbon (DOC), the major and trace element concentrations over three major open water seasons. On the annual scale, the majority of dissolved elements including organic carbon increased their concentration from 30 to 500%, with a statistically significant (p < 0.05) trend from spring to winter. The concentrations of most trace elements (TEs) increased in the order spring > summer > autumn > winter. The ice formation in October included several stages: first, surface layer freezing followed by crack (fissure) formation with unfrozen water from the deeper layers spreading over the ice surface. This water was subsequently frozen and formed layered ice rich in organic matter. As a result, the DOC and metal (Mn, Fe, Ni, Cu, Zn, As, Ba and Pb) concentrations were highest near the surface of the ice column (0 to 20 cm) and decreased by a factor of 2 towards the bottom. The main implications of discovered freeze-driven solute concentrations in thermokarst lake waters are enhanced colloidal coagulation and removal of dissolved organic matter and associated insoluble metals from the water column to the sediments. The measured distribution coefficients of a TE between amorphous organo-ferric coagulates and lake water (<0.45 μm) were similar to those reported earlier for Fe-rich colloids and low molecular weight (<1 kDa, or <1–2 nm) fractions of thermokarst lake waters, suggesting massive co-precipitation of TE with amorphous Fe oxyhydroxide stabilized by organic matter. Although the concentration of most elements was lowest in spring, this period of maximal water coverage of land created a significant reservoir of DOC and soluble metals in the water column that can be easily mobilized to the hydrological network. The highest DOC concentration observed in the smallest (<100 m2) water bodies in spring suggests their strongly heterotrophic status and, therefore, a potentially elevated CO2 flux from the lake surface to the atmosphere.

Thermokarst (thaw) lakes of the Western Siberian Lowland (WSL), the World´s largest permafrost peatland, contain important but poorly constrained stocks of organic carbon (OC) and nitrogen. These lakes are highly vulnerable to climate warming and permafrost thaw. The present work aims to quantify the OC and total nitrogen (TN) stocks and accumulation rates in sediments of 11 thermokarst lakes in the WSL across a permafrost gradient, from isolated to discontinuous and continuous permafrost. We found an increase in OC and TN stocks in lake sediments (0–30 cm) from the northern taiga with sporadic permafrost (285 Tg C and 10.5 Tg N) to the tundra zone with continuous permafrost (628 Tg C and 26 Tg N). The upper 30 cm thermokarst lake sediments of the permafrost-affected WSL store 1250 ± 35 Tg C and 50 ± 1.4 Tg N). The OC accumulation rates in thermokarst lake sediments ranged from 36 to 250 g C m⁻² year⁻¹, which is 5 to 10 times higher than C accumulation rates in peatlands of western Siberia. The total OC accumulation in lakes of WSL is 7.8 ± 0.7 Tg C year⁻¹. This is about 24–47% of the C emission from the WSL thermokarst lakes, implying that it represents an important factor in the C budget to consider in order to understand impacts of climate change and permafrost thaw on the C cycle.

Multidrug-resistant and extensively-drug-resistant Pseudomonas aeruginosa are increasing therapeutic challenges worldwide. We did a longitudinal epidemiological and clinical study of extensively-drug-resistant P aeruginosa in Belarus, Kazakhstan, and Russia. The study was done in three prospectively defined phases: Jan 1, 2002–Dec 31, 2004; Jan 1, 2006–Dec 31, 2007; and Jan 1, 2008–Dec 31, 2010. The first two phases were in Russia only. All consecutive, non-duplicate, nosocomial isolates and case report forms were sent to the coordinating centre (Institute of Antimicrobial Chemotherapy, Smolensk, Russia), where species reidentification, susceptibility testing, and molecular typing of isolates were done. We did susceptibility testing by agar dilution. The presence of metallo-β-lactamase (MBL) genes was established by PCR and sequencing, and class 1 integrons containing MBL gene cassettes were analysed by the PCR restriction fragment length polymorphism approach. Strain relatedness was analysed by multiple loci variable-number tandem-repeat (VNTR) analysis (at six VNTR loci) and multilocus sequence typing. In 2002–04, 628 of 1053 P aeruginosa isolates were insusceptible to carbapenems and 47 (4·5%) possessed MBLs. In 2006–07, 584 of 787 isolates were insusceptible to carbapenems and 160 (20·3%) possessed MBLs. In 2008–10, 1238 of 1643 Russian P aeruginosa isolates were insusceptible to carbapenems and 471 (28·7%) possessed MBLs. Additionally, the 32 P aeruginosa isolates from Belarus and Kazakhstan were all carbapenem insusceptible and all possessed MBLs. More than 96% of MBL-positive P aeruginosa isolates were resistant to all antibiotics except colistin (ie, extensively drug resistant), and, in 2010, 5·9% were resistant to colistin. 685 (96·5%) of 710 MBL-positive P aeruginosa belonged to ST235. blaVIM-2 genes were detected in 707 (99·6%) of 710 MBL-positive isolates. Extensively-drug-resistant ST235 P aeruginosa has rapidly spread throughout Russia and into Belarus and Kazakhstan via clonal dissemination. Increases in the use of colistin will probably result in further spread of ST235 P aeruginosa resistant to all drugs. HEFC, Ministry of Health of the Russian Federation, Government of the Republic of Belarus, Government of the Republic of Kazakhstan, European Union, Medical Research Council UK–Canada partnership.

To be able to control the functions of engineered multicomponent nanomaterials, a detailed understanding of heterogeneous nucleation at the nanoscale is essential. Here, by using in situ synchrotron X-ray scattering, we show that in the heterogeneous nucleation and growth of Au on Pt or Pt-alloy seeds the heteroepitaxial growth of the Au shell exerts high stress (∼2 GPa) on the seed by forming a core/shell structure in the early stage of the reaction. The development of lattice strain and subsequent strain relaxation, which we show using atomic-resolution transmission electron microscopy to occur through the slip of {111} layers, induces morphological changes from a core/shell to a dumbbell structure, and governs the nucleation and growth kinetics. We also propose a thermodynamic model for the nucleation and growth of dumbbell metallic heteronanostructures. The detailed nucleation and growth kinetics and the crystal structure of catalytically relevant CoPt 3 /Au, FePt/Au and Pt/Au metal dumbbell nanoparticles have been obtained by in situ synchrotron small- and wide-angle X-ray scattering techniques.