Marked Transition Research Articles

The formation of Neoarchean continental crust in the south-east Superior Craton by two distinct geodynamic processes

The formation of the continental crust in the early Earth, and the geodynamics that drove it, are fundamental to understanding the evolution of our planet, but remain intensely debated. Here, we analysed 148 archived zircon separates of magmatic rocks for in-situ zircon U-Pb-Hf-O-trace element data, and compiled published geochronological, whole-rock geochemical and Sm-Nd isotopic data from across the south-east Superior Craton, Canada. We combine these data spatially and temporally to investigate the crustal evolution of this part of the craton in the Neoarchean, with a view to understanding its tectonic setting. In terms of zircon data, at >2704–2695 Ma, the central and north-west Abitibi demonstrate more juvenile εHf, light to mantle-like δ18O, lower (Eu/Eu*)/Y (drier/shallower crust), reduced ΔFMQ, less continental initial-U (Ui)/Yb, and more mantle-like Ui/Nb, relative to surrounding crust, which contains older, ca. 2800–2750 Ma inherited and magmatic zircon ages. Furthermore, whole-rock Sr/Y and La/Sm demonstrate the presence of a high Sr/Y TTG component (mainly intrusive) surrounding zones of low Sr/Y (mainly volcanic) component, the latter of which shows contamination trends with Mesoarchean crust. We interpret this to represent a continental-rift setting, driven by plume magmatism as represented by multiple komatiite suites. At ca. 2704–2695 Ma, there is a marked transition in multiple datasets, including; increases in δ18O, (Eu/Eu*)/Y, ΔFMQ, Ui/Yb and Ui/Nb data, together with more distinct arc-like trace element trends, suggesting a transition to north-dipping subduction. This process closed the rift system and initiated orogenesis. Subsequently, this study constrains the geodynamic setting which formed the majority of Neoarchean continental crust in the south-east Superior Craton, and the timing at which it transitioned to subduction. If these findings are replicated in other cratons, it suggests that plate tectonics was active by, or started at, ca. 2.7 Ga.

Explosively driven dynamic compaction of granular media

This paper reports experimental investigations into the dynamic compaction of particle rings subjected to moderate explosions confined in a radial Hele-Shaw cell. The findings reveal marked transitions in the flow regimes corresponding to the evolution of the transient pressure fields inside the granular medium induced by unsteady gas infiltration. As the pressure fields evolve from being localized to diffusive with a substantial reduction in intensity, three sequent flow regimes with distinct rheologies are identified. Specifically, these flow regimes are found to be governed by the localized strong pressure field, then the competition between the diffusive pressure field and wall friction, and finally, solid stresses in the presence of rarefaction waves. A Bingham-type rheology can adequately describe the granular compaction when the pressure gradients remain the dominant driving forces, whereas the frictional nature of the granular flows becomes increasingly significant as the solid stresses set in. As the pressure gradients phase out, rarefaction decompaction commences. However, this only manages to relax the innermost layers of the compacted particles due to a distinctive compressive deformation pattern, giving rise to a discontinuous flow field. These findings shed light on the rheology of dense granular flows subjected to unsteady pressure loadings involving diverse flow–particle and particle–particle interactions.

Method of semantic application verification in GPGPU technology

An application development and verification method for massively parallel systems using NVIDIA GPUs is proposed. The method allows creating models at different levels of abstraction using the apparatus of marked transition systems. The compositions (product) of such systems are transformed into a Petri net, which are then analyzed by appropriate means. The proposed method allows specifying model properties by temporal logic formulas. This allows studying the properties of massively parallel systems which is almost impossible to analyze manually, since the number of execution threads in the latest NVIDIA video adapter architectures (Pascal, Volta, Turing, Ampere) is measured in hundreds of thousands or millions.

Modulation of physical properties of organic cocrystals by amino acid chirality

Amino acid chirality plays an important role in conveying directionality and specificity to their supramolecular organization. However, the impact of enantiopure and racemic amino acids on the favorable packing and macroscopic properties of organic cocrystals with nonchiral coformers is poorly understood. Herein, we performed a systematic study of the effect of chirality on the macroscopic properties of acetylated alanine (AcA) single crystals and cocrystals with a nonchiral photo-sensitive bipyridine derivative (BPE). Cocrystallization with BPE produced a marked morphology transition that improved the supramolecular chirality, thermal stability and mechanical strength of AcA crystals. The distinct supramolecular packing modes were analyzed by X-ray crystallography. The highest rigidity was observed for BPE/dl-AcA, while BPE/d-AcA and BPE/l-AcA crystals exhibited higher efficiency of photo-induced emission for fluorescent imprinting, as well as significantly higher piezoelectricity. This work provides a striking illustration that subtle differences in amino acid stereochemistry translate into tunable macroscopic properties of organic cocrystals for future applications in rigid solids, fluorescent imprinting, and energy harvesting.

Wind Generation and the Dynamics of Electricity Prices in Australia

Australia's National Electricity Market (NEM) is experiencing one of the world's fastest and marked transitions toward variable renewable energy generation. This transformation poses challenges to system security and reliability and has triggered increased variability and uncertainty in electricity prices. By employing an exponential generalized autoregressive conditional heteroskedasticity (eGARCH) model, we gauge the effects of wind power generation on the dynamics of electricity prices in the NEM. We find that a 1 GWh increase in wind generation decreases daily prices up to 1.3 AUD/MWh and typically increases price volatility up to 2%. Beyond consumption and gas prices, hydro generation also contributes to an increase in electricity prices and their volatility. The cross-border interconnectors play a significant role in determining price levels and volatility dynamics. This underscores the important role of strategic provisions and investment in the connectivity within the NEM to ensure the reliable and effective delivery of renewable energy generation. Regulatory interventions, such as the carbon pricing mechanism and nationwide lockdown restrictions due to COVID-19 pandemic, also had a measurable impact on electricity price dynamics.

Paleoenvironments from robust loess stratigraphy using high-resolution color and grain-size data of the last glacial Krems-Wachtberg record (NE Austria)

The complex interplay of dust sedimentation, pedogenesis, and erosion/reworking in the formation of loess-paleosol sequences (LPS) challenges paleoenvironmental proxies. Here we show that color and grain size are essential parameters characterizing loess profiles and support robust stratigraphies as a basis for reconstructions in the context of local geo-ecological and large-scale paleoclimatic evolution. Detailed paleoenvironmental records from the period since the arrival of anatomically modern humans to the last glacial maximum are scarce in the Alpine surroundings. The c. 7.5 m thick LPS Krems-Wachtberg, NE Austria, known for its well-preserved Upper Paleolithic context at a depth of 5.5 m, formed between 40 and 20 ka BP by quasi-continuous dust-sedimentation, interrupted by phases of incipient pedogenesis and local reworking. The new KW2015 composite is based on three sections studied and sampled at 2.5 cm resolution. Color and grain size data support a robust stratigraphy for reconstructions of the pedosedimentary evolution. The marked transition from oxidized to reduced paleosols of KW2015 around 34–35 ka corresponds to the Middle-to Upper Pleniglacial transition as part of a general cooling trend from marine isotope stage (MIS) 3 to 2, intensely modulated by millennial-scale climatic fluctuations as recorded in the Greenland ice core data. The distinct response of KW2015 to these trends highlights that reconstructing LPS evolution based on a robust stratigraphy is a prerequisite to paleoenvironmental proxy interpretation.

Characterisation of the first electronically excited state of protonated acetylene C2H3 + by coincident imaging photoelectron spectroscopy

ABSTRACT We present a combined experimental and theoretical study of the threshold photoelectron spectroscopy of the vinyl radical encompassing the first triplet excited state of the vinyl cation. The radicals were produced in a flow-tube reactor by hydrogen abstraction of C2H4 and CH4 using fluorine atoms generated in a microwave discharge. Vinyl was ionised with synchrotron vacuum ultraviolet radiation. A double imaging coincidence setup was used to record the threshold photoelectron spectrum. The experimental and simulated spectra show a marked adiabatic transition to the 3A′′ state with a short vibrational progression dominated by the C = C stretching mode. The adiabatic ionisation energy to this state is measured precisely at 10.747 ± 0.008 eV. In combination with the adiabatic ionisation energy to the 1A1 state from the Active Thermochemical Tables (ATcT), we find a singlet–triplet gap of 2.27 ± 0.01 eV (219 ± 1 kJ mol−1). Calculated ionisation energies and Franck–Condon factors for the singlet 1A′′ excited state are also given.

Differential influences of early growth and social factors on young children's cognitive performance in four low-and-middle-income birth cohorts (Brazil, Guatemala, Philippines, and South Africa).

BackgroundStudies relating childhood cognitive development to poor linear growth seldom take adequate account of social conditions related to both, leading to a focus on nutrition interventions. We aimed to assess the roles of both biological and social conditions in determining early childhood cognition, mediated by birthweight and early linear growth.MethodsAfter exploratory structural equation modelling to identify determining factors, we tested direct and indirect paths to cognitive performance through birthweight and child height-for-age at 2 years, assessed between 4 and 8.5 years of age among 2448 children in four birth cohort studies in low-and-middle-income countries (Brazil, Guatemala, Philippines and South Africa). Determinants were compared across the cohorts.FindingsThree factors yielded excellent fit, comprising birth endowment (primarily maternal age and birth order), household resources (crowding, dependency) and parental capacity (parental education). We estimated their strength together with maternal height in determining cognitive performance. Percentage shares of total effects of the four determinants show a marked transition from mainly biological determinants of birth weight (birth endowment 34%) and maternal height (30%) compared to household resources (25%) and parental capacity (11%), through largely economic determinants of height at 2 years (household resources (60%) to cognitive performance being predominantly determined by parental capacity (64%) followed by household resources (29%). The largely biological factor, birth endowment (maternal age and birth order) contributed only 7% to childhood cognitive performance and maternal height was insignificant. In summary, the combined share of social total effects (household resources and parental capacity) rises from 36∙2% on birth weight, to 78∙2% on height for age at 24 m, and 93∙4% on cognitive functioning.InterpretationAcross four low- and middle-income contexts, cognition in childhood is influenced more by the parental capacity of families and their economic resources than by birth weight and early linear growth. Improving children's cognitive functioning requires multi-sectoral interventions to improve parental education and enhance their economic wellbeing, interventions that are known to improve also early childhood growth.

Upper mantle structure of the northeastern Arabian Platform from teleseismic body-wave tomography

A thick Infra-Cambrian to Phanerozoic sedimentary sequence in eastern Arabia conceals a poorly known Neoproterozoic basement that once separated the currently exposed Arabian Shield (western Arabia) from NW India in Gondwana. In this study, the Arabian Platform (eastern Arabia) is targeted by relatively high-resolution passive-source seismic tomography for the first time, which aims to illuminate crust and upper mantle structure in order to make inferences on their nature and origin. This is facilitated by a new broadband seismic network of 55 stations in the United Arab Emirates (UAE), which has recorded sufficient teleseismic body wave data to allow for the determination of three-dimensional seismic structure. Using a grid-based eikonal solver and a subspace inversion technique implemented in FMTOMO, relative arrival-time residuals from teleseismic earthquakes are mapped as 3-D P-wave velocity perturbations in the upper mantle beneath the seismic network. The resultant tomographic images reveal a marked transition from higher velocities in the Gulf of Oman to lower velocities in the west that we interpret to indicate the lithospheric boundary between Cretaceous Tethyan oceanic lithosphere and the Arabian passive continental margin. The northern extent of Tethyan oceanic lithosphere appears to terminate against a possible offshore continuation of the Dibba fault, until now only identified onshore. Further inland, the tomographic model exhibits a number of low- and high- velocity anomalies with a predominant NW orientation. Significantly, one well-defined high velocity anomaly is situated along strike of the Neoproterozoic exposure of volcanic-arc granodiorites found in northern Oman. We relate this anomaly to an intra-oceanic arc created during the Tonian subduction of the Mozambique Ocean, which strongly support the idea of continental growth in the Arabian Platform via magmatic arc accretion.

Gravitational Transitions Increase Blood-brain Barrier Permeability In Humans

Scientific Abstract While spaceflight-associated neuro-ocular syndrome (SANS) related to intracranial hypertension (IH) is considered NASA’s top health risk for long-duration spaceflight, the underlying mechanisms remain unclear. PURPOSE: To examine if repeated bouts of micro- and hypergravity during parabolic flight (PF) would increase blood-brain barrier (BBB) permeability subsequent to the combined effects of cerebral hyper-perfusion (hemodynamic) and systemic oxidative-nitrosative (molecular) stress. METHODS: Six participants (5♂, 1♀) aged 29 ± 11 years were examined before, during and after PF. Six gender and age- matched (27 ± 6 years) controls were subject to the same procedures/experimental timeline with the exception of PF. Duplex ultrasound was employed to measure blood flow in the anterior (internal carotid artery, ICA) and posterior (vertebral artery, VA) circulation, with venous blood assayed for biomarkers specific to oxidative-nitrosative stress (electron paramagnetic resonance spectroscopy/ozone-based chemiluminescence) and structural integrity of the neurovascular unit (NVU, chemiluminescence/ELISA). RESULTS: PF was associated with a selective increase in VA flow during the most marked gravitational transition from micro- to hypergravity (P < 0.05). Increases in oxidative-nitrosative stress, glio-vascular GFAP and S100ß were observed after PF (P > 0.05), the latter proportional to the increase in VA flow, whereas biomarkers of neuronal-axonal damage (neuron-specific enolase, neurofilament light-chain, ubiquitin carboxy-terminal hydrolase L1 and tau) remained stable (P > 0.05). CONCLUSION: Collectively, these data are the first to demonstrate that acute gravitational transitions result in minor BBB disruption due to the combined effects of hemodynamic-molecular stress thereby proposing an alternative candidate mechanism and biomarkers for the reported neurological sequelae underlying SANS.

Assessing paraglacial processes at Nexpayantla Gorge (Popocatépetl volcano, Central Mexico) using OSL and14C

AbstractWe evaluate the paraglacial activity in Nexpayantla, a subtropical mountainous gorge in Popocatépetl volcano (Central Mexico), fully deglaciated in the 20th century. Glacial advances are evidenced by the presence of moraines. Fluvio‐glacial terraces and an alluvial megafan resulted from the gorge deglaciation. Current reworking of the glacigenic material is done by landslides and debris flows produced on the moraines and terraces. To study the different phases of mobilization of glacigenic sediment, we used an approach based on the study of the optically stimulated luminescence (OSL) signals obtained from a portable OSL (POSL) reader in samples extracted from both glacigenic and paraglacial deposits. The luminescence (POSL) results obtained at moraines increase as altitude decreases, which is expected for deglaciated valleys where the oldest moraines are located at lower elevations. We evaluate the grade of luminescence signal reset of the glacigenic sediments during the proglacial stage, and the subsequent deglaciation phases. Our results indicate that there is a marked transition between glacial and fluvially dominated processes at Nexpayantla Gorge. We find that the grade of luminescence signal resetting in the paraglacial deposits is a good indicator to trace paraglacial stages and the beginning of exhaustion of the paraglacial activity in mountain areas. OSL ages confirm that the oldest fluvio‐glacial terraces found at the middle sector of Nexpayantla Gorge are ~2 ka, which is also supported by an AMS14C age. OSL dating was found challenging, since quartz grains have low sensitivity because of their volcanic origin; POSL signals, however, are in good agreement with the location and distribution of geomorphic markers. We propose that luminescence data obtained from the POSL unit can be useful to provide information about sediment mobilization in paraglacial environments during different climatic pulses – even for the case where mineral grains have low sensitivity, such as in volcanic sediments. © 2020 John Wiley &amp; Sons, Ltd.

Gravitational Transitions Increase Posterior Cerebral Perfusion and Systemic Oxidative-nitrosative Stress: Implications for Neurovascular Unit Integrity

The present study examined if repeated bouts of micro- and hypergravity during parabolic flight (PF) alter structural integrity of the neurovascular unit (NVU) subsequent to free radical-mediated changes in regional cerebral perfusion. Six participants (5♂, 1♀) aged 29 ± 11 years were examined before, during and after a 3 h PF and compared to six sex and age-matched (27 ± 6 years) normogravity controls. Blood flow was measured in the anterior (middle cerebral artery, MCA; internal carotid artery, ICA) and posterior (vertebral artery, VA) circulation (duplex ultrasound) in-flight over the course of 15 parabolas. Venous blood was assayed for free radicals (electron paramagnetic resonance spectroscopy), nitric oxide (NO, ozone-based chemiluminescence) and NVU integrity (chemiluminescence/ELISA) in normogravity before and after exposure to 31 parabolas. While MCA velocity did not change (P > 0.05), a selective increase in VA flow was observed during the most marked gravitational transition from micro- to hypergravity (P < 0.05). Increased oxidative-nitrosative stress defined by a free radical-mediated reduction in NO and elevations in glio-vascular GFAP and S100ß were observed after PF (P < 0.05), the latter proportional to the increase in VA flow (r = 0.908, P < 0.05). In contrast, biomarkers of neuronal-axonal damage (neuron-specific enolase, neurofilament light-chain, ubiquitin carboxy-terminal hydrolase L1 and tau) did not change (P > 0.05). Collectively, these findings suggest that the cumulative effects of repeated gravitational transitions may promote minor blood–brain barrier disruption, potentially related to the combined effects of haemodynamic (posterior cerebral hyperperfusion) and molecular (systemic oxidative-nitrosative) stress.

Structural insights into assembly, operation and inhibition of a type I restriction-modification system.

Type I restriction-modification (R-M) systems are widespread in prokaryotic genomes and provide robust protection against foreign DNA. They are multisubunit enzymes with methyltransferase, endonuclease and translocase activities. Despite extensive studies over the past five decades, little is known about the molecular mechanisms of these sophisticated machines. Here, we report the cryo-electron microscopy structures of the representative EcoR124I R-M system in different assemblies (R2M2S1, R1M2S1 and M2S1) bound to target DNA and the phage and mobile genetic element-encoded anti-restriction proteins Ocr and ArdA. EcoR124I can precisely regulate different enzymatic activities by adopting distinct conformations. The marked conformational transitions of EcoR124I are dependent on the intrinsic flexibility at both the individual-subunit and assembled-complex levels. Moreover, Ocr and ArdA use a DNA-mimicry strategy to inhibit multiple activities, but do not block the conformational transitions of the complexes. These structural findings, complemented by mutational studies of key intermolecular contacts, provide insights into assembly, operation and inhibition mechanisms of type I R-M systems.

NMR insights into the pre-amyloid ensemble and secretion targeting of the curli subunit CsgA

The biofilms of Enterobacteriaceae are fortified by assembly of curli amyloid fibres on the cell surface. Curli not only provides structural reinforcement, but also facilitates surface adhesion. To prevent toxic intracellular accumulation of amyloid precipitate, secretion of the major curli subunit, CsgA, is tightly regulated. In this work, we have employed solution state NMR spectroscopy to characterise the structural ensemble of the pre-fibrillar state of CsgA within the bacterial periplasm, and upon recruitment to the curli pore, CsgG, and the secretion chaperone, CsgE. We show that the N-terminal targeting sequence (N) of CsgA binds specifically to CsgG and that its subsequent sequestration induces a marked transition in the conformational ensemble, which is coupled to a preference for CsgE binding. These observations lead us to suggest a sequential model for binding and structural rearrangement of CsgA at the periplasmic face of the secretion machinery.

Strain-rate dependence of the dynamic softening in a duplex stainless steel

The dynamic softening mechanism of a 2205 duplex stainless steel is comprehensively investigated through hot compression at the temperature of 1000 °C and the strain rates of 0.01 to 10 s−1. It is shown that an increase in the strain rate leads to a marked transition in the softening mechanism of ferrite. The ferrite is found to soften through the sub-grain coalescence at a low strain rate of 0.01 s−1 and via the continuous dynamic recrystallization (CDRX) at an intermediate strain rate of 1 s−1. While, at a high strain rate of 10 s−1, a softening mechanism akin to the discontinuous dynamic recrystallization (DDRX) is observed taking place. The applicable softening mechanism of ferrite in the duplex steel is largely associated with the formation of misoriented sub-grains and their evolution adapted to applied strain rates. By contrast, the softening within austenite is remarkably limited at all applied strain rates. At the low strain rate of 0.01 s−1, the dynamic softening may start through a mechanism analogous to the CDRX. Whereas the DRX nucleation at the high strain rate of 10 s−1 mainly occurs through the strain-induced boundary migration (SIBM). At the intermediate strain rate of 1 s−1, however, sluggish kinetics of DRX in austenite is observed since the two kinds of nucleation mechanisms both are depressed.

Abstract P2-11-20: Endocrine resistance in breast cancer: A dynamic gene expression analysis approach reveals potential new responsible genes

Abstract While ER-targeted endocrine therapies are the most successful therapies for ER-positive breast cancer, tumor recurrence and endocrine-resistance happens in many of the cases. Despite efforts, the underlying genes and mechanisms of this acquired resistance remain largely unknown. Here, we utilized a recently developed pipeline for dynamic gene regulatory network analysis1to re-analyze the publically available datasets related to endocrine resistance in breast cancer in order to find new target genes related to endocrine resistance. The pipeline exploits the time-resolved expression pattern of genes to identify dynamic responsive genes (DRG) and group them into multiple modules based on the similarity in their dynamic activities, which leads us to identify more significant genes compared with previous gene expression analysis models that solely focus on expression value of the genes. Here, we analyzed a dataset of time-resolved gene expression during MCF-7 cell transition to endocrine-resistant cells by long-term deprivation of estrogen, which is an accepted model of endocrine resistance2. The dataset is publically available as GES20361 in the Gene Expression Omnibus (GEO) database. Based on their dynamic expression pattern over time, our method of analysis grouped genes into three main modules. Interestingly, the majority of well-studied genes in the literature related to endocrine resistance are part of one of these modules, while there are many genes such as GABPA, TFDP1, MCM7, MDC1, and FOXC1 that are potential novel targets for treatments against endocrine resistance. Module One included genes related to endocrine resistance, mainly those related to cell cycle, such as CCNA1, CCNA2, CCND1, and CDK family, and DNA replication and repair, such as MDC1 and PARP1, as well as EGFR. Consistent with the previous literature on endocrine resistant breast cancer cells, these genes all showed similar up-regulated expression patterns over time. Furthermore, our model confirmed the identified genes shown in the previous paper2 (POLD1, TERF1, RAF1, and E2F1) as part of Module One and as important genes in endocrine resistance regulation. Module Two was enriched for genes related to PI3K/AKT/mTOR signaling pathway, while Module Three mostly contained tyrosine kinase related genes, which not only confirms the previous findings related to the importance of these genes in acquiring endocrine resistance, but also indicates the difference between the expression patterns of these genes compare to cell cycle genes and those in Module One. Our analysis revealed that the genes in Module One continued their up-regulating trend beyond day 90, when the marked transition toward resistance happens and resistance phenotype starts to arise, while genes in Module Two got up-regulated before the 90 days and down-regulated afterward, suggesting different roles from the genes in Module One. Lastly, we studied the gene regulatory networks, transcription factors, and miRNAs upstream of the identified genes, and discovered several interesting targets, such as MiR-193b and MiR-16, which have integral parts in the regulation of our identified genes and thus can be of great importance toward endocrine resistance.

In Vitro Functional and Structural Characterization of A Synthetic Clinical Pulmonary Surfactant with Enhanced Resistance to Inhibition

CHF5633 is a novel synthetic clinical pulmonary surfactant preparation composed by two phospholipid species, dipalmitoyl phosphatidylcholine (DPPC) and palmitoyloleoyl phosphatidylglycerol (POPG), and synthetic analogues of the hydrophobic surfactant proteins SP-B and SP-C. In this study, the interfacial properties of CHF5633 in the absence and in the presence of inhibitory serum proteins have been assessed in comparison with a native surfactant purified from porcine lungs and with poractant alpha, a widely used clinical surfactant preparation. The study of the spreading properties of CHF5633 in a Wilhelmy balance, its ability to adsorb and accumulate at air-liquid interfaces as revealed by a multiwell fluorescence assay, and its dynamic behavior under breathing-like compression-expansion cycling in a Captive Bubble Surfactometer (CBS), all revealed that CHF5633 exhibits a good behavior to reduce and sustain surface tensions to values below 5 mN/m. CHF5633 shows somehow slower initial interfacial adsorption than native surfactant or poractant alpha, but a better resistance to inhibition by serum proteins than the animal-derived clinical surfactant, comparable to that of the full native surfactant complex. Interfacial CHF5633 films formed in a Langmuir-Blodgett balance coupled with epifluorescence microscopy revealed similar propensity to segregate condensed lipid domains under compression than films made by native porcine surfactant or poractant alpha. This ability of CHF5633 to segregate condensed lipid phases can be related with a marked thermotropic transition from ordered to disordered membrane phases as exhibited by differential scanning calorimetry (DSC) of CHF5633 suspensions, occurring at similar temperatures but with higher associated enthalpy than that shown by poractant alpha. The good interfacial behavior of CHF5633 tested under physiologically meaningful conditions in vitro and its higher resistance to inactivation by serum proteins, together with its standardized and well-defined composition, makes it a particularly useful therapeutic preparation to be applied in situations associated with lung inflammation and edema, alone or in combined strategies to exploit surfactant-facilitated drug delivery.

A Genealogy of Dissent: The Progeny of Fallen Royals in Chosŏn by Eugene Y. Park

Reviewed by: A Genealogy of Dissent: The Progeny of Fallen Royals in Chosŏn by Eugene Y. Park Carl Young Park, Eugene Y. – A Genealogy of Dissent: The Progeny of Fallen Royals in Chosŏn Korea. Stanford, CA: Stanford University Press, 2019. Pp. 270. What happens to the descendants of a royal family when it is overthrown? This is the question that Eugene Park tackles in his new book, A Genealogy of Dissent. Park investigates the case of the descendants of the fallen Kaesŏng Wang clan in Korea after their Koryŏ kingdom was overthrown by the new Chosŏn kingdom in the late 1300s. By drawing on family histories, government records, and royal chronicles, Park pieces together what happened to different lineages in the Wang clan for several centuries up to the present day and their fate through the oftenturbulent course of Korean history. Park presents several case studies that reveal these lineages' relations with the new dynasty and how Neo-Confucian ideas of family structures and rituals manifested themselves in the history of the Wang clan. The result is an interesting insight into an East Asian society's political, social, and familial structures and how it marked dynastic transition. In the first decades after the overthrow of the Wang family and the establishment of the new Chosŏn kingdom, most of the direct royal line was massacred and the rest of the clan scattered and went into hiding. The killing of the old ruler and heirs did cause some discomfort among the Chosŏn ruling elite (many of whom had roots in the previous dynasty's elite families) and rumours began questioning [End Page 707] the parentage and legitimacy of the last rulers of Koryŏ to better justify their murders. The new Chosŏn ruling house also relied on the Confucian discourse on the "Mandate of Heaven," emphasizing that the old regime was chaotic and corrupt and that Heaven therefore mandated a new ruling house to bring peace and order to the country. However, another element of Confucian discourse emphasized that part of the success of a new dynasty depended on properly treating both the ancestral spirits and the descendants of the old dynasty. Buddhist services were periodically performed for the souls of the old monarchs, but as Confucianism was becoming increasingly important in Korea as the official ideology of the Chosŏn dynasty, Confucian shrines were constructed in places associated with the Koryŏ royal family to perform the ancestral memorial services in their honour. After searching to destroy the Koryŏ royal family, the Chosŏn ruling house now embarked to find members of the Wang clan closest to the royal line to be the stewards of these new shrines and perform the ceremonies for their ancestors to assure the peace and success of the new kingdom. There was also a search to give special access to office for the descendants of the old royal house. This proved to be a difficult task, however, since the purges had proven to be all too successful. Nevertheless, certain lineages did emerge, distantly descended from one or another of the Koryŏ kings, to take on these new offices. Much of the book is dedicated to the search of the Chosŏn government for these officers, which was often a difficult task because of the paucity of descendants and doubts as to their real connections to the royal house. Success in the Chosŏn power structure strongly depended on successfully passing the civil service examinations based on Confucian learning. In general, in spite of their illustrious ancestry and the government's attempts to facilitate their access to government positions, only a few members of the Kaesŏng Wang clan passed the highest examinations and obtained central government posts during the 500 years of the Chosŏn kingdom's existence up to the early twentieth century. The Wangs were mainly low key, with some lineages being the guardians of the shrines and others gaining prominence in their localities. This is where the title "a genealogy of dissent" is a bit of a misnomer. Members of the Wang clan did not lead dissident movements or rebellions (there was no Korean "Bonnie Prince Charlie...

Widespread drying of European peatlands in recent centuries

Climate warming and human impacts are thought to be causing peatlands to dry, potentially converting them from sinks to sources of carbon. However, it is unclear whether the hydrological status of peatlands has moved beyond their natural envelope. Here we show that European peatlands have undergone substantial, widespread drying during the last ~300 years. We analyse testate amoeba-derived hydrological reconstructions from 31 peatlands across Britain, Ireland, Scandinavia and Continental Europe to examine changes in peatland surface wetness during the last 2,000 years. We find that 60% of our study sites were drier during the period 1800–2000 CE than they have been for the last 600 years, 40% of sites were drier than they have been for 1,000 years and 24% of sites were drier than they have been for 2,000 years. This marked recent transition in the hydrology of European peatlands is concurrent with compound pressures including climatic drying, warming and direct human impacts on peatlands, although these factors vary among regions and individual sites. Our results suggest that the wetness of many European peatlands may now be moving away from natural baselines. Our findings highlight the need for effective management and restoration of European peatlands.

A double ITCZ phenomenology of wind errors in the equatorial Atlantic in seasonal forecasts with ECMWF models

Abstract. Modern coupled general circulation models produce systematic biases in the tropical Atlantic that hamper the reliability of long-range predictions. This study focuses on a common springtime westerly wind bias in the equatorial Atlantic in seasonal hindcasts from two coupled models – ECMWF System 4 and EC-Earth v2.3 – and in hindcasts also based on System 4, but with prescribed sea-surface temperatures. The development of the equatorial westerly bias in early April is marked by a rapid transition from a wintertime easterly, cold tongue bias to a springtime westerly bias regime that displays a marked double intertropical convergence zone (ITCZ). The transition is a seasonal feature of the model climatology (independent of initialisation date) and is associated with a seasonal increase in rainfall where a second branch of the ITCZ is produced south of the Equator. Excess off-equatorial convergence redirects the trade winds away from the Equator. Based on arguments of temporal coincidence, the results of our analysis contrast with those from previous work, and alleged causes hereto identified as the likely cause of the equatorial westerly bias in other models must be discarded. Quite in general, we find no evidence of remote influences on the development of the springtime equatorial bias in the Atlantic in the IFS-based models. Limited evidence however is presented that supports the hypothesis of an incorrect representation of the meridional equatorward flow in the marine boundary layer of the southern Atlantic as a contributing factor. Erroneous dynamical constraints on the flow upstream of the Equator may generate convergence and associated rainfall south of the Equator. This directs attention to the representation of the properties of the subtropical boundary layer as a potential source for the double ITCZ bias.