Disparate impacts of the Eldgjá and Laki flood-lava eruptions

The Eldgjá eruption of ~ 939 AD is recognised as the largest in Iceland since Settlement, and ranks among the largest late-Holocene volcanic episodes on Earth. It disgorged > 21.0 km3 (Dense Rock Equivalent) of magma as lava flows (~ 19.7 km3) and tephra deposits (> 1.3 km3 DRE), comprising alternating phreatomagmatic (wet) and magmatic (dry) explosive phases. Tephra deposits up to four metres thick buried proximal areas, and extreme quantities of sulphur and other volatiles were released into the atmosphere. Little is known about the environmental and societal impacts of the eruption within Iceland as it took place during the initial decades of human settlement, and before written record-keeping in Iceland became prevalent. In this work, we review what is known of the Eldgjá eruption, making comparisons with the better documented Laki eruption of 1783–1784 AD (~ 15.1 km3 DRE). While the Eldgjá eruption was volumetrically greater, probably longer-lasting, and involved phreatomagmatic explosive phases, we reason that societal resilience to volcanic hazards was likely stronger in the 10th century compared with the 18th, reflecting differences in social and natural capital in Iceland. Accordingly, the impacts of the Eldgjá eruption cannot be inferred reliably from knowledge of the Laki episode and its aftermath

Assessing a Pilot Scheme of Intensive Support and Assertive Linkage in Levels of Engagement, Retention, and Recovery Capital for people in Recovery Housing using Quasi-Experimental Methods

Introduction: There is strong and ever-growing evidence highlighting the effectiveness of recovery housing to support and sustain substance use disorder (SUD) recovery augmented by intensive support comprising assertive linkages to community services.Aim: To assess a pilot intensive recovery support (IRS) intervention for individuals (n=175) entering certified Level II and III recovery residences who met at least three out of five conditions (no health insurance; no driving license; substance use in the last 14 days; currently unemployed; having less than $75 capital) and its impact on engagement, retention and changes in recovery capital for individuals compared with a business-as-usual Standard Recovery Support (SRS) approach (n=1,758).Methods: We deployed quasi-experimental techniques to create weighted and balanced counterfactual groups derived from the Recovery Capital (REC-CAP) assessment tool to compare outcomes for people receiving the pilot IRS compared to intervention against SRS.Results: After reweighting for resident demographics, service needs, and barriers to recovery, those receiving IRS exhibited improved retention rates, reduced likelihood of disengagement, and growth in recovery capital after living in the residence for 6-9 months.Conclusion: Our findings from this pilot intervention suggest that intensive recovery support incorporating assertive community linkages and enhanced recovery coaching can improve engagement, length of stay and recovery capital growth compared to a balanced counterfactual group. We suggest that this model may be particularly beneficial to those entering Level II and Level III recovery housing with lower levels of recovery capital at admission entry.<br/

Portacaval shunt causes apoptosis and liver atrophy in rats despite increases in endogenous levels of major hepatic growth factors

Background/Aims: The response to the liver damage caused by portacaval shunt (PCS) is characterized by low-grade hyperplasia and atrophy. To clarify mechanisms of this dissociation, we correlated the expression of 'hepatotrophic factors' and the antihepatotrophic and proapoptotic peptide, transforming growth factor (TGF)-β, with the pathologic changes caused by PCS in rats. Methods: PCS was created by side-to-side anastomosis between the portal vein and inferior vena cava, with ligation of the hilar portal vein. Hepatic growth mediators were measured to 2 months. Results: The decrease in the liver/body weight ratio during the first 7 days which stabilized by day 15, corresponded to parenchymal cell apoptosis and increases in hepatic TGF-β concentration that peaked at 1.4 × baseline at 15 days before returning to control levels by day 30. Variable increases in the concentrations of growth promoters (hepatocyte growth factor, TGF-α and augmenter of liver regeneration) also occurred during the period of hepatocellular apoptosis. Conclusions: The development of hepatic atrophy was associated with changes in TGF-β concentration, and occurred despite increased expression of multiple putative growth promoters. The findings suggest that apoptosis set in motion by TGF-β constrains the amount of hepatocyte proliferation independently from control of liver volume. © 2002 European Association for the Study of the Liver. Published by Elsevier Science B.V. All rights reserved

Characterization and assessment of lung and bone marrow derived endothelial cells and their bone regenerative potential

Angiogenesis is important for successful fracture repair. Aging negatively affects the number and activity of endothelial cells (ECs) and subsequently leads to impaired bone healing. We previously showed that implantation of lung-derived endothelial cells (LECs) improved fracture healing in rats. In this study, we characterized and compared neonatal lung and bone marrow-derived endothelial cells (neonatal LECs and neonatal BMECs) and further asses3sed if implantation of neonatal BMECs could enhance bone healing in both young and aged mice. We assessed neonatal EC tube formation, proliferation, and wound migration ability in vitro in ECs isolated from the bone marrow and lungs of neonatal mice. The in vitro studies demonstrated that both neonatal LECs and neonatal BMECs exhibited EC traits. To test the function of neonatal ECs in vivo, we created a femoral fracture in young and aged mice and implanted a collagen sponge to deliver neonatal BMECs at the fracture site. In the mouse fracture model, endochondral ossification was delayed in aged control mice compared to young controls. Neonatal BMECs significantly improved endochondral bone formation only in aged mice. These data suggest BMECs have potential to enhance aged bone healing. Compared to LECs, BMECs are more feasible for translational cell therapy and clinical applications in bone repair. Future studies are needed to examine the fate and function of BMECs implanted into the fracture sites

Assessment of risk of insect-resistant transgenic crops to nontarget arthropods

An international initiative is developing a scientifically rigorous approach to evaluate the potential risks to nontarget arthropods (NTAs) posed by insect-resistant, genetically modified (IRGM) crops. It adapts the tiered approach to risk assessment that is used internationally within regulatory toxicology and environmental sciences. The approach focuses on the formulation and testing of clearly stated risk hypotheses, making maximum use of available data and using formal decision guidelines to progress between testing stages (or tiers). It is intended to provide guidance to regulatory agencies that are currently developing their own NTA risk assessment guidelines for IRGM crops and to help harmonize regulatory requirements between different countries and different regions of the world

Role of Novelty Seeking Personality Traits as Mediator of the Association between COMT and Onset Age of Drug Use in Chinese Heroin Dependent Patients

Personality traits such as novelty seeking (NS) are associated with substance dependence but the mechanism underlying this association remains uncertain. Previous studies have focused on the role of the dopamine pathway.Examine the relationships between allelic variants of the catechol-O-methyltransferase (COMT) gene, NS personality traits, and age of onset of drug use in heroin-dependent subjects in China.The 478 heroin dependent subjects from four drug rehabilitation centers in Shanghai who were genotyped for eight tagging single nucleotide polymorphisms (SNP) on the COMT gene completed the NS subscale from the Temperament and Character Inventory. Multivariate analyses were used to assess the potential mediating role of NS personality traits in the association between COMT gene variants and the age of onset of heroin use.In the univariate analysis the COMT rs737866 gene variants were independently associated with both NS and age of onset of drug use: those with the TT genotype had higher NS subscale scores and an earlier onset age of heroin use than individuals with CT or CC genotypes. In the multivariate analysis the inclusion of the NS subscore variable weakened the relationship between the COMT rs737866 TT genotype and an earlier age of onset of drug use. Our findings that COMT is associated with both NS personality traits and with the age of onset of heroin use helps to clarify the complex relationship between genetic and psychological factors in the development of substance abuse

Overcoming leakage in scalable quantum error correction

Leakage of quantum information out of computational states into higher energy states represents a major challenge in the pursuit of quantum error correction (QEC). In a QEC circuit, leakage builds over time and spreads through multi-qubit interactions. This leads to correlated errors that degrade the exponential suppression of logical error with scale, challenging the feasibility of QEC as a path towards fault-tolerant quantum computation. Here, we demonstrate the execution of a distance-3 surface code and distance-21 bit-flip code on a Sycamore quantum processor where leakage is removed from all qubits in each cycle. This shortens the lifetime of leakage and curtails its ability to spread and induce correlated errors. We report a ten-fold reduction in steady-state leakage population on the data qubits encoding the logical state and an average leakage population of less than $1 \times 10^{-3}$ throughout the entire device. The leakage removal process itself efficiently returns leakage population back to the computational basis, and adding it to a code circuit prevents leakage from inducing correlated error across cycles, restoring a fundamental assumption of QEC. With this demonstration that leakage can be contained, we resolve a key challenge for practical QEC at scale.Comment: Main text: 7 pages, 5 figure

Suppressing quantum errors by scaling a surface code logical qubit

Practical quantum computing will require error rates that are well below what is achievable with physical qubits. Quantum error correction offers a path to algorithmically-relevant error rates by encoding logical qubits within many physical qubits, where increasing the number of physical qubits enhances protection against physical errors. However, introducing more qubits also increases the number of error sources, so the density of errors must be sufficiently low in order for logical performance to improve with increasing code size. Here, we report the measurement of logical qubit performance scaling across multiple code sizes, and demonstrate that our system of superconducting qubits has sufficient performance to overcome the additional errors from increasing qubit number. We find our distance-5 surface code logical qubit modestly outperforms an ensemble of distance-3 logical qubits on average, both in terms of logical error probability over 25 cycles and logical error per cycle ($2.914\%\pm 0.016\%$ compared to $3.028\%\pm 0.023\%$). To investigate damaging, low-probability error sources, we run a distance-25 repetition code and observe a $1.7\times10^{-6}$ logical error per round floor set by a single high-energy event ($1.6\times10^{-7}$ when excluding this event). We are able to accurately model our experiment, and from this model we can extract error budgets that highlight the biggest challenges for future systems. These results mark the first experimental demonstration where quantum error correction begins to improve performance with increasing qubit number, illuminating the path to reaching the logical error rates required for computation.Comment: Main text: 6 pages, 4 figures. v2: Update author list, references, Fig. S12, Table I