The thermo-tectonic evolution of the Suckling-Dayman metamorphic core complex, southeastern Papua New Guinea

<p>The Suckling-Dayman metamorphic core complex (SDMCC) in the Woodlark Rift of southeastern Papua New Guinea is being exhumed along the Mai’iu Fault, an active low-angle normal fault dipping ~20-22° northwards at the surface. The spectacularly smooth topography of the Mai’iu Fault footwall clearly is expressive of geologically recent uplift. The precise timing and rates of the exhumation of this continental metamorphic core complex (MCC) have, however, never been studied in detail. This thesis provides the first systematic set of U-Pb, fission track (FT), (U-Th[-Sm])/He and ²⁶Al/¹⁰Be ages from metaigneous and metasedimentary rocks of the footwall of the SDMCC, clasts and a tephra deposit contained within syn-tectonic conglomerates (the Gwoira Conglomerate) in a rider block, and modern stream sediments in the footwall and hanging wall of the Mai’iu Fault. The ages are complemented by whole-rock compositional and thermobarometric data (Al-in-amphibole, Al-in-biotite, Raman spectroscopy of carbonaceous material). Based on these data, the timing of the onset of extension along the Mai’iu Fault, its long-term dip-slip rate and its initial dip were constrained. These data are presented in the context of the evolution of the SDMCC from the Cretaceous to the present. The dominant lithology of the SDMCC, the Goropu Metabasalt, formed in a marginal basin to the northeast of the Australian continent. Two zircon U-Pb ages of 103.0 ± 5.7 and 71.6 ± 3.3 Ma, indicative of maximum depositional ages, from metasedimentary intercalations (the Bonenau Schist) in the Goropu Metabasalt, suggest formation of the oceanic protolith in the Late Cretaceous. Between 60.4 ± 2.5 and 56.6 ± 2.3 Ma (zircon U-Pb), tholeiitic to mildly calc-alkaline gabbroic to tonalitic rocks of the Yau Igneous Complex intruded the Goropu Metabasalt. The age of the Yau Igneous Complex overlaps with the known timing of north-directed subduction of the oceanic lithosphere along the Owen Stanley Fault (OSF) beneath the Cape Vogel Arc and provides a minimum age for the oceanic protolith. A second phase of magmatism, consisting of peraluminous-metaluminous calc-alkaline (Suckling Granite) and high-K (Mai’iu Monzonite, Bonua Porphyry) granitoids and basaltic andesite dikes that were cut by the Mai’iu Fault, was associated with the tectonic inversion of the OSF. Zircons from these syn-extensional intrusions suggest crystallization between 3.8 ± 0.2 and 2.0 ± 0.1 Ma. The oldest age of this range is inferred to mark the time by which the OSF had been re-activated as an extensional structure, the Mai’iu Fault. Al-in-amphibole and -biotite thermobarometry suggests crystallization of the Suckling Granite and Mai’iu Monzonite in a relatively shallow crust (~2-8 km depth) at pressures of ~0.4-2.3 kbar. Inherited zircons in the Plio-Pleistocene granitoids indicate that the Goropu Metabasalt carapace of the SDMCC is underlain by Australian-derived Cretaceous crustal material that is inferred to be the continuation of the Kagi Metamorphics in the central Papuan Peninsula. Further constraints of the timing of unroofing of the SDMCC were determined from three quartz clasts in the Gwoira Conglomerate. ²⁶Al/¹⁰Be burial ages of these samples indicate deposition in the Pliocene between 4.6 ± 2.9 and 3.4 ± 2.1 Ma. A tephra in the upper section of the exposed conglomerates was dated employing U-Pb methods on zircon, combined with apatite, zircon and magnetite (U-Th[-Sm])/He chronometers, yielding a complex age spectrum. An eruption age of 0.6 ± 0.4 Ma was extrapolated for this tephra. FT and (U-Th[-Sm])/He low-temperature thermochronometry details a young (≤3 Ma) and rapid exhumation history. Based on the crystallization ages of the syn-extensional granitoids, the depositional age of the Gwoira Conglomerate, the extensional cooling recorded by low-temperature thermochronometry, and the backwards projection of the published Holocene dip-slip rate of the Mai’iu Fault, the timing of the onset of extension is estimated at ~4 Ma. A minimum dip-slip rate of 8.1 ± 1.3 km/myr has been calculated from the inverse slope of zircon (U-Th)/He (ZHe) ages with slip-parallel distance from Mai’iu Fault trace. This is slightly lower than the >12 km/myr required to restore the intrusion depths (2-8 km) of the syn-extensional granitoids, now exposed 20-25 km south of the Mai’iu Fault trace at elevations up to 3.4 km. Collectively, these constraints suggest that the Mai’iu Fault has moved at cm-per-year rates since ~3 Ma. Evidence for both a fossil zircon FT (ZFT) partial annealing zone (PAZ) and a ZHe partial retention zone (PRZ) on the footwall of the SDMCC is presented. Combining paleo-temperature estimates from the inferred bases of the zircon PAZ and PRZ, peak-metamorphic temperatures inferred from Raman spectroscopy of carbonaceous material (RSCM), and published peak-metamorphic temperature constraints on the extensional shear zone mylonites near the Mai’iu Fault trace, a minimum slip-parallel, down-dip paleo-temperature gradient of 9.7 ± 2.2°C/km has been estimated for the exhumed Mai’iu Fault plane. Assuming that the modern regional geothermal gradient in the Woodlark Rift is a maximum estimate of that which existed prior to extensional exhumation of the SDMCC, the paleo-temperature gradient was used to estimate an average initial dip of the Mai’iu Fault of ~44° for pre-extensional geothermal gradients ranging between 10 to 20°C/km. Presently dipping 20-22° at the surface, the constraints on the initial dip suggest that the Mai’iu Fault may have been back-rotated by >20° since the onset of extension, consistent with a rolling hinge-style evolution of this continental MCC.</p>

The thermo-tectonic evolution of the Suckling-Dayman metamorphic core complex, southeastern Papua New Guinea

<p>The Suckling-Dayman metamorphic core complex (SDMCC) in the Woodlark Rift of southeastern Papua New Guinea is being exhumed along the Mai’iu Fault, an active low-angle normal fault dipping ~20-22° northwards at the surface. The spectacularly smooth topography of the Mai’iu Fault footwall clearly is expressive of geologically recent uplift. The precise timing and rates of the exhumation of this continental metamorphic core complex (MCC) have, however, never been studied in detail. This thesis provides the first systematic set of U-Pb, fission track (FT), (U-Th[-Sm])/He and ²⁶Al/¹⁰Be ages from metaigneous and metasedimentary rocks of the footwall of the SDMCC, clasts and a tephra deposit contained within syn-tectonic conglomerates (the Gwoira Conglomerate) in a rider block, and modern stream sediments in the footwall and hanging wall of the Mai’iu Fault. The ages are complemented by whole-rock compositional and thermobarometric data (Al-in-amphibole, Al-in-biotite, Raman spectroscopy of carbonaceous material). Based on these data, the timing of the onset of extension along the Mai’iu Fault, its long-term dip-slip rate and its initial dip were constrained. These data are presented in the context of the evolution of the SDMCC from the Cretaceous to the present. The dominant lithology of the SDMCC, the Goropu Metabasalt, formed in a marginal basin to the northeast of the Australian continent. Two zircon U-Pb ages of 103.0 ± 5.7 and 71.6 ± 3.3 Ma, indicative of maximum depositional ages, from metasedimentary intercalations (the Bonenau Schist) in the Goropu Metabasalt, suggest formation of the oceanic protolith in the Late Cretaceous. Between 60.4 ± 2.5 and 56.6 ± 2.3 Ma (zircon U-Pb), tholeiitic to mildly calc-alkaline gabbroic to tonalitic rocks of the Yau Igneous Complex intruded the Goropu Metabasalt. The age of the Yau Igneous Complex overlaps with the known timing of north-directed subduction of the oceanic lithosphere along the Owen Stanley Fault (OSF) beneath the Cape Vogel Arc and provides a minimum age for the oceanic protolith. A second phase of magmatism, consisting of peraluminous-metaluminous calc-alkaline (Suckling Granite) and high-K (Mai’iu Monzonite, Bonua Porphyry) granitoids and basaltic andesite dikes that were cut by the Mai’iu Fault, was associated with the tectonic inversion of the OSF. Zircons from these syn-extensional intrusions suggest crystallization between 3.8 ± 0.2 and 2.0 ± 0.1 Ma. The oldest age of this range is inferred to mark the time by which the OSF had been re-activated as an extensional structure, the Mai’iu Fault. Al-in-amphibole and -biotite thermobarometry suggests crystallization of the Suckling Granite and Mai’iu Monzonite in a relatively shallow crust (~2-8 km depth) at pressures of ~0.4-2.3 kbar. Inherited zircons in the Plio-Pleistocene granitoids indicate that the Goropu Metabasalt carapace of the SDMCC is underlain by Australian-derived Cretaceous crustal material that is inferred to be the continuation of the Kagi Metamorphics in the central Papuan Peninsula. Further constraints of the timing of unroofing of the SDMCC were determined from three quartz clasts in the Gwoira Conglomerate. ²⁶Al/¹⁰Be burial ages of these samples indicate deposition in the Pliocene between 4.6 ± 2.9 and 3.4 ± 2.1 Ma. A tephra in the upper section of the exposed conglomerates was dated employing U-Pb methods on zircon, combined with apatite, zircon and magnetite (U-Th[-Sm])/He chronometers, yielding a complex age spectrum. An eruption age of 0.6 ± 0.4 Ma was extrapolated for this tephra. FT and (U-Th[-Sm])/He low-temperature thermochronometry details a young (≤3 Ma) and rapid exhumation history. Based on the crystallization ages of the syn-extensional granitoids, the depositional age of the Gwoira Conglomerate, the extensional cooling recorded by low-temperature thermochronometry, and the backwards projection of the published Holocene dip-slip rate of the Mai’iu Fault, the timing of the onset of extension is estimated at ~4 Ma. A minimum dip-slip rate of 8.1 ± 1.3 km/myr has been calculated from the inverse slope of zircon (U-Th)/He (ZHe) ages with slip-parallel distance from Mai’iu Fault trace. This is slightly lower than the >12 km/myr required to restore the intrusion depths (2-8 km) of the syn-extensional granitoids, now exposed 20-25 km south of the Mai’iu Fault trace at elevations up to 3.4 km. Collectively, these constraints suggest that the Mai’iu Fault has moved at cm-per-year rates since ~3 Ma. Evidence for both a fossil zircon FT (ZFT) partial annealing zone (PAZ) and a ZHe partial retention zone (PRZ) on the footwall of the SDMCC is presented. Combining paleo-temperature estimates from the inferred bases of the zircon PAZ and PRZ, peak-metamorphic temperatures inferred from Raman spectroscopy of carbonaceous material (RSCM), and published peak-metamorphic temperature constraints on the extensional shear zone mylonites near the Mai’iu Fault trace, a minimum slip-parallel, down-dip paleo-temperature gradient of 9.7 ± 2.2°C/km has been estimated for the exhumed Mai’iu Fault plane. Assuming that the modern regional geothermal gradient in the Woodlark Rift is a maximum estimate of that which existed prior to extensional exhumation of the SDMCC, the paleo-temperature gradient was used to estimate an average initial dip of the Mai’iu Fault of ~44° for pre-extensional geothermal gradients ranging between 10 to 20°C/km. Presently dipping 20-22° at the surface, the constraints on the initial dip suggest that the Mai’iu Fault may have been back-rotated by >20° since the onset of extension, consistent with a rolling hinge-style evolution of this continental MCC.</p>

Adolescents’ Social Environment and Executive Functions Predict Long-term Mental Health and Feelings of Future Uncertainty Throughout the COVID-19 Pandemic

The COVID-19 pandemic has negatively impacted adolescents’ mental health (i.e. mood and life satisfaction). Some adolescents are at risk to be disproportionally hit by the pandemic due to vulnerabilities in their social environment. In the present longitudinal study, we explored adolescents’ mood trajectories throughout the pandemic, and whether vulnerabilities in the social environment (i.e. household and socioeconomic hardship) predicted adolescents’ mental health directly and indirectly through feelings of uncertainty about the future. We also investigated whether executive functions and age buffered these relationships. In total, 177 Dutch-speaking adolescents aged 10 – 18 years (Mage = 15.64, SDage = 1.72, 80% females at T1) participated in all three waves (T1= May 2020, T2 = November 2020, T3 = May 2021) of an online survey. Mood results demonstrated that feelings of vigor stabilized, after an initial dip between T1 and T2, but that feelings of tension and depression continued to increase throughout the pandemic. Higher exposure to household and socioeconomic hardship predicted negative mood and lower life satisfaction and was mediated by feelings of uncertainty about the future. Irrespective of the exposure to household and socioeconomic hardship, adolescents with better executive functions reported better mood in the aftermath of the pandemic, partially due to lower feelings of future uncertainty. However, no associations were observed with life satisfaction. These novel findings imply that adolescents’ mental health issues may outlast the COVID-19 pandemic. Nonetheless, executive functioning is a protective factor operating via feelings of future uncertainty, which makes them promising mechanistic targets for intervention.

Glycemic efficacy and safety of the SGLT2 inhibitor ertugliflozin in patients with type 2 diabetes and stage 3 chronic kidney disease: an analysis from the VERTIS CV randomized trial

IntroductionHere we report the glycemic efficacy and safety of ertugliflozin in patients in the VERTIS CV cardiovascular outcome trial with chronic kidney disease (CKD) stage 3.Research design and methodsPrespecified and post-hoc analyses were performed in patients with an estimated glomerular filtration rate (eGFR) 30–<60 mL/min/1.73 m2 at screening. The primary endpoint was glycemic efficacy at week 18. Longer term glycemic efficacy and changes in body weight, systolic blood pressure (SBP), and eGFR were also evaluated.ResultsAmong 8246 patients in VERTIS CV, 1776 patients had CKD stage 3; 1319 patients had CKD stage 3A (eGFR 45–<60 mL/min/1.73 m2); 457 patients had CKD stage 3B (eGFR 30–<45 mL/min/1.73 m2). Week 18 least squares (LS)-mean (95% CI) placebo-adjusted changes from baseline in glycated hemoglobin (HbA1c) for 5 mg and 15 mg ertugliflozin were −0.27% (−0.37% to –0.17%) and −0.28% (−0.38% to –0.17%), respectively, for CKD stage 3 overall and −0.27% (−0.38% to –0.15%) and −0.31% (−0.43% to –0.19%), respectively, for CKD stage 3A (all p<0.001). For CKD stage 3B, the reduction in HbA1c for 5 mg ertugliflozin was −0.28% (−0.47% to –0.08%) (p=0.006) and for 15 mg ertugliflozin was −0.19% (−0.39% to 0.01%) (p=0.064). LS-mean placebo-adjusted reductions in body weight (range: −1.32 to −1.95 kg) and SBP (range: −2.42 to −3.41 mm Hg) were observed across CKD stage 3 categories with ertugliflozin. After an initial dip, eGFR remained above or near baseline with ertugliflozin treatment. The incidence of overall adverse events (AEs), symptomatic hypoglycemia, hypovolemia, and kidney-related AEs did not differ between ertugliflozin and placebo across CKD stage 3 subgroups.ConclusionsIn VERTIS CV patients with CKD stage 3A, ertugliflozin resulted in reductions in HbA1c, body weight and SBP, maintenance of eGFR, and was generally well tolerated. Results in the CKD stage 3B subgroup were generally similar except for an attenuated HbA1c response with the 15 mg dose.Trial registration numberNCT01986881.

Impact of Demonetization on Indian Banking Sector

Demonetization refers to the process of stripping of currency unit of its status as legal tender. Demonetization was announced on 8th November, 2016 by the honorable Prime Minister, Mr. Narender Modi with the objective to remove black money, corruption, terrorism and counterfeit notes. Demonetization was a massive step taken by the government of India which had an immense effect on the Indian economy especially on the banking sector as banks forms the core sector of Indian economy. The study aims at finding an insight of impact of demonetization on banking sector, the results indicates demonetization had an initial dip in the short run but in the long run demonetization is going to have a positive impact on the Indian economy in the form of reduced corruption, greater digitalization, tax compliance and better formalization of the Indian economy.

The Role of Cerebral Metabolism in Improving Time Pressured Decisions

Speed-accuracy tradeoff (SAT) theory dictates that decisions can be made more quickly by sacrificing accuracy. Here we investigate whether the human brain can operate in a brief metabolic overdrive to overcome SAT and successfully make decisions requiring both high levels of speed and accuracy. In the context of BOLD fMRI we expect “a brief metabolic overdrive” to involve an increase in cerebral oxygen metabolism prior to increased cerebral blood flow–a phenomenon known as the “initial dip” which results from a sudden drop in oxyhemoglobin in perfusing blood. Human subjects performed a motion discrimination task consisting of different difficulties while emphasizing either accuracy (i.e., without time pressure) or both speed and accuracy (i.e., with time pressure). Using simultaneous multi-slice fMRI, for very fast (333 ms) measurement of whole brain BOLD activity, revealed two modes of physiological overdrive responses when subjects emphasized both speed and accuracy. The majority of subjects exhibited the hypothesized enhancement of initial dip amplitude in posterior visual cortex (PVC) with the size of the enhancement significantly correlated with improvement in behavioral performance. For these subjects, the traditionally analyzed post-stimulus overshoot was not affected by task emphasis. These results demonstrate the complexity and variability of the BOLD hemodynamic response. The discovered relationships between BOLD response and behavior were only observed when subjects emphasized both speed and accuracy in more difficult trials suggesting that the brain can perform in a state of metabolic overdrive with enhanced neural processing of sensory information specifically in challenging situations.

Mallet fractures: a prospective comparison of treatment outcomes

Background: The optimal management of mallet fractures is controversial. Currently, published evidence does not clearly define the role of surgery in managing these fractures or identify when splinting alone is suitable.Methods: An observational, prospective cohort study was undertaken between 2012 and 2015 evaluating patient experience, and radiological and functional outcomes following mallet fractures managed with splinting alone or surgery combined with post-operative splinting. This study was registered with our local research facility and ethical approval was granted by the New Zealand Northern B Health and Disability Ethics Committee Health and Disability Ethics Committee (HDEC) #13/NTB/202. All patients provided formal written consent. Results: A total of 109 adult patients with 113 mallet fractures were enrolled in the study and 85 patients with 89 fractures completed follow-up. Mean follow-up was 190 days. Fractures initially associated with subluxation of the distal interphalangeal (DIP) joint treated with splinting alone were five times more likely to fail to meet a minimum standard of success than those fixed with surgery. When the fracture fragment occupies between one and two thirds of the joint surface, even in the absence of initial DIP joint subluxation, 13/35 (37%) joints subluxed during splint treatment. Conclusion: This study aids clinicians by highlighting where splinting is likely to fail and providing a means of identifying injuries in which surgery must be considered

Marriage and Divorce Decline During the COVID-19 Pandemic: A Case Study of Five States

The decline in marriage and divorce was evident prior to the pandemic, but it remains unknown whether these patterns have persisted during the pandemic. We compared monthly marriage and divorce counts for two years prior to the pandemic (2018 and 2019), and during the pandemic for the five states that published monthly vital statistics data for 2020 (Arizona, Florida, Missouri, New Hampshire, Oregon). All five states witnessed an initial dip in marriage. Counts of marriages in Arizona and New Hampshire rebounded. In contrast, a marriage shortfall occurred in Florida, Missouri, and Oregon. In the early pandemic months divorces initially declined in all five states and rebounded in Arizona. In the remaining four states a divorce shortfall has occurred. Based on these results we provide national estimates of the marriage and divorce response to the pandemic. As more data become available it will be important to acknowledge these state variations in response to the pandemic.

Linking serial homicide – towards an ecologically valid application

Purpose Crime linkage analysis (CLA) can be applied in the police investigation-phase to sift through a database to find behaviorally similar cases to the one under investigation and in the trial-phase to try to prove that the perpetrator of two or more offences is the same, by showing similarity and distinctiveness in the offences. Lately, research has moved toward more naturalistic settings, analyzing data sets that are as similar to actual crime databases as possible. One such step has been to include one-off offences in the data sets, but this has not yet been done with homicide. The purpose of this paper is to investigate how linking accuracy of serial homicide is affected as a function of added hard-to-solve one-off offences. Design/methodology/approach A sample (N = 117–1160) of Italian serial homicides (n = 116) and hard-to-solve one-off homicides (n = 1–1044, simulated from 45 cases) was analyzed using a Bayesian approach to identify series membership, and a case by case comparison of similarity using Jaccard’s coefficient. Linking accuracy was evaluated using receiver operating characteristics and by examining the sensitivity and specificity of the model. Findings After an initial dip in linking accuracy (as measured by the AUC), the accuracy increased as more one-offs were added to the data. While adding one-offs made it easier to identify correct series (increased sensitivity), there was an increase in false positives (decreased specificity) in the linkage decisions. When rank ordering cases according to similarity, linkage accuracy was affected negatively as a function of added non-serial cases. Practical implications While using a more natural data set, in terms of adding a significant portion of non-serial homicides into the mix, does introduce error into the linkage decision, the authors conclude that taken overall, the findings still support the validity of CLA in practice. Originality/value This is the first crime linkage study on homicide to investigate how linking accuracy is affected as a function of non-serial cases being introduced into the data.