Spatial and depth‐dependent variations in magma volume addition and addition rates to continental arcs: Application to global CO_2 fluxes since 750 Ma

Magma transfer from the mantle to the crust in arcs is an important step in the global cycling of elements and volatiles from Earth's interior to the atmosphere. Arc intrusive rocks dominate the total magma mass budget over extrusive rocks. However, their total volume and rate of addition is still poorly constrained, especially in continental arcs. We present lateral (forearc to backarc) and depth‐dependent (volcanics to deep crust) magma volume additions and arc‐wide magma addition rates (MARs) calculated from three continental arc crustal sections preserving magma flare‐up periods. We observe an increase in volume addition with depth and less magma added in the forearc (~15%) and backarc (~10% to 30%) compared to the main arc. Crustal‐wide MARs for each section are remarkably similar and around 0.7–0.9 km^3/km^2/Ma. MARs can be used to estimate CO_2 fluxes from continental arcs. With initial magma CO_2 contents of 1.5 wt.%, global continental arc lengths, and MARs, we calculate changes in C (Mt/year) released from continental arcs since 750 Ma. Calculated present‐day global C fluxes are similar to values constrained by other methods. Throughout the Phanerozoic, assuming equal durations of flare‐up and lull magmatism, calculated continental CO_2 flux rates vary between 4 and 18 Mt C/year with highest values in the Mesozoic. These fluxes are considered minima since the intake of mantle and/or crustal carbon is not considered. Magmatic episodicity in continental arcs and changes in arc thickness and width are critical to consider when calculating MARs through time

Spatiotemporally heterogeneous deformation, indirect tectonomagmatic links, and lithospheric evolution during orogenic activity coeval with an arc flare-up

Broad overlap between deformation and magmatism in active margins has spurred the development of a conceptual framework of direct tectonomagmatic links in both active and ancient arcs. Although widespread and highly influential, such models have only rarely been critically evaluated. Rigorously linking tectonism, geodynamics, lithospheric evolution, and arc activity requires detailed reconstructions of the spatiotemporal patterns of magmatism and deformation across both a sufficiently wide area and a range of observational scales. Herein, new constraints on the timing, extent, and characteristics of deformation during mid-Cretaceous tectonism in the central Sierra Nevada (eastern California, USA) are synthesized with published geologic mapping, structural studies, and geochronology to create an updated reconstruction of one of the type examples of a hot, magma-rich orogen. Tilted strata, tectonic fabrics, and shear zones with variable geometries, kinematics, intensity, and timing reveal a significantly revised record of ~25 m.y. of heterogeneous deformation ca. 105–80 Ma. Deformation and magmatism show distinct and unrelated spatiotemporal patterns throughout this orogenic episode. Contrary to previous models of direct tectonomagmatic links, many of which were developed in the central Sierra Nevada, arc activity did not control the location, intensity, or kinematics of intra-arc deformation, nor did shear zones control the location of magmatism. Furthermore, arc lithosphere appears to have strengthened, rather than weakened, as the arc-orogenic flare-up proceeded. In addition to changing plate-scale boundary conditions, lithospheric-scale rheological evolution likely played a key role in the patterns of Late Cretaceous deformation observed across strike of the entire Cordilleran margin

LiDAR mapping of tidal marshes for ecogeomorphological modelling in the TIDE project

The European research project TIDE (Tidal Inlets Dynamics and Environment) is developing and validating coupled models describing the morphological, biological and ecological evolution of tidal environments. The interactions between the physical and biological processes occurring in these regions requires that the system be studied as a whole rather than as separate parts. Extensive use of remote sensing including LiDAR is being made to provide validation data for the modelling. This paper describes the different uses of LiDAR within the project and their relevance to the TIDE science objectives. LiDAR data have been acquired from three different environments, the Venice Lagoon in Italy, Morecambe Bay in England, and the Eden estuary in Scotland. LiDAR accuracy at each site has been evaluated using ground reference data acquired with differential GPS. A semi-automatic technique has been developed to extract tidal channel networks from LiDAR data either used alone or fused with aerial photography. While the resulting networks may require some correction, the procedure does allow network extraction over large areas using objective criteria and reduces fieldwork requirements. The networks extracted may subsequently be used in geomorphological analyses, for example to describe the drainage patterns induced by networks and to examine the rate of change of networks. Estimation of the heights of the low and sparse vegetation on marshes is being investigated by analysis of the statistical distribution of the measured LiDAR heights. Species having different mean heights may be separated using the first-order moments of the height distribution

Spatial and depth‐dependent variations in magma volume addition and addition rates to continental arcs: Application to global CO_2 fluxes since 750 Ma

Magma transfer from the mantle to the crust in arcs is an important step in the global cycling of elements and volatiles from Earth's interior to the atmosphere. Arc intrusive rocks dominate the total magma mass budget over extrusive rocks. However, their total volume and rate of addition is still poorly constrained, especially in continental arcs. We present lateral (forearc to backarc) and depth‐dependent (volcanics to deep crust) magma volume additions and arc‐wide magma addition rates (MARs) calculated from three continental arc crustal sections preserving magma flare‐up periods. We observe an increase in volume addition with depth and less magma added in the forearc (~15%) and backarc (~10% to 30%) compared to the main arc. Crustal‐wide MARs for each section are remarkably similar and around 0.7–0.9 km^3/km^2/Ma. MARs can be used to estimate CO_2 fluxes from continental arcs. With initial magma CO_2 contents of 1.5 wt.%, global continental arc lengths, and MARs, we calculate changes in C (Mt/year) released from continental arcs since 750 Ma. Calculated present‐day global C fluxes are similar to values constrained by other methods. Throughout the Phanerozoic, assuming equal durations of flare‐up and lull magmatism, calculated continental CO_2 flux rates vary between 4 and 18 Mt C/year with highest values in the Mesozoic. These fluxes are considered minima since the intake of mantle and/or crustal carbon is not considered. Magmatic episodicity in continental arcs and changes in arc thickness and width are critical to consider when calculating MARs through time

Construction, Emplacement, and Geochemical Evolution of Deep-Crustal Intrusions: Tenpeak and Dirtyface Plutons, North Cascades, Western North America

Deep plutonic systems represent an important link between lower-crustal melt-generation sites and higher-level regions of magma accumulation, but models for these systems are limited by the relative scarcity of exposed weakly deformed, deep-crustal plutons. Exceptions include the ca. 92.3–89.7 Ma, dominantly tonalitic Tenpeak pluton and the smaller, nearby ca. 91 Ma Dirtyface pluton of the North Cascades (western North America), which represent deeply exposed crustal levels (∼25–35 km) of a Cordilleran arc. Initial subduction-driven magmatism in the Tenpeak pluton was marked by co-magmatic hydrous mafic and felsic magmas, which formed gabbro, diorite, tonalite, and hornblendite within a heterogeneous mafic complex. High-MgO, Ni and Cr tonalitic magmas (Schaefer Lake subtype) with (εNd)0 of +4.8 to +5.8 accompanied or shortly followed this magmatism, and typify the Dirtyface intrusion. This early magmatism formed moderately to steeply dipping sheets, which are best developed in the southwestern margin of the Tenpeak pluton and in an internal zone with host rock rafts. As the system evolved, a different source was tapped to produce typical calc-alkaline magmas (Indian Creek subtype) that are more isotopically evolved (initial εNd = +3.0 to +4.0). Magmas of this subtype formed bodies that are elliptical in map view and that truncated internal magmatic contacts and more strongly deformed tonalite, compatible with removal of older solidified and magmatic materials. The Schaefer Lake subtype terminated or was overwhelmed by the Indian Creek subtype in the youngest, high-volume magmas of the Tenpeak pluton. Both plutons have moderately to steeply dipping contacts that define the shape of an elongate asymmetric funnel to wedge. During sheet emplacement, magma wedging isolated and rotated rafts and blocks of host meta-supracrustal rock. Vertical, mostly downward transport of host rock by ductile flow and at least modest stoping were important during emplacement of the larger bodies. Only small ephemeral magma chambers formed in the early stages of pluton construction, but larger bodies (tens of cubic kilometers) probably remained mushy during crystallization of the relatively homogeneous younger tonalites. The juxtaposition of different magma subtypes, at least local mixing at the emplacement level, and removal and/or recycling of older magmas indicates that magmas from different sources utilized the same conduit for a protracted time interval. Large volumes of magma probably ascended through the system to form the larger and relatively more homogeneous intrusions in the shallow levels of the arc. This magma was likely filtered and homogenized by processes operating at the Tenpeak level. The end result was a deep- to shallow-crustal, steep, irregularly shaped magmatic system

Hemostatic efficacy of an advanced bipolar sealer in open gynecologic, thoracic, and colectomy procedures: A prospective cohort study

Background An advanced bipolar (ABP) tissue sealer designed for division of major vessels in open procedures was evaluated in a prospective post-market study. The objective was to provide clinical data for assessment of vessel transection, hemostatic performance and ease of use of the ABP device during open colectomy, gynecologic, and thoracic operations. Materials and methods The ABP test device was used in colectomy (n = 36), gynecologic (n = 44), and thoracic (n = 21) procedure groups. Vessels transected with the ABP device were graded intraoperatively on a hemostasis scale of 1–4, defined as follows: Grade1, no bleeding; Grade 2, minor bleeding with no intervention; Grade 3, minor bleeding requiring touchup with the test device or monopolar cautery; and Grade 4, significant bleeding requiring intervention with any additional hemostatic product. The primary performance measure was the percentage of vessels that achieved hemostasis grades ≤3. The primary safety endpoint was the summarization of all ABP device-related adverse events (AEs). Results For all three procedure groups together, 302 (96.2%) of 314 total vessel transections were scored as hemostasis grades ≤ 3, including 270 (86.0%) that were rated Grade 1. Twelve transections (3.8%) were Grade 4, which included 9 vessels transected in the gynecologic group and 3 in the thoracic group. Three subjects experienced a total of 4 device-related AEs, consisting of hematoma, hypotension, procedural pain, and superficial thermal burn. All 4 device-related AEs were mild in severity. Conclusion The advanced bipolar device exhibited effective hemostasis, an acceptable safety profile, and ease of use during colectomy, thoracic, and gynecologic procedures

Mechanisms involved in acquisition of blaNDM genes by IncA/C2 and IncFIIY plasmids

blaNDM genes confer carbapenem resistance and have been identified on transferable plasmids belonging to different incompatibility (Inc) groups. Here we present the complete sequences of four plasmids carrying a blaNDM gene, pKP1-NDM-1, pEC2-NDM-3, pECL3-NDM-1, and pEC4-NDM-6, from four clinical samples originating from four different patients. Different plasmids carry segments that align to different parts of the blaNDM region found on Acinetobacter plasmids. pKP1-NDM-1 and pEC2-NDM-3, from Klebsiella pneumoniae and Escherichia coli, respectively, were identified as type 1 IncA/C2 plasmids with almost identical backbones. Different regions carrying blaNDM are inserted in different locations in the antibiotic resistance island known as ARI-A, and ISCR1 may have been involved in the acquisition of blaNDM-3 by pEC2-NDM-3. pECL3-NDM-1 and pEC4-NDM-6, from Enterobacter cloacae and E. coli, respectively, have similar IncFIIY backbones, but different regions carrying blaNDM are found in different locations. Tn3-derived inverted-repeat transposable elements (TIME) appear to have been involved in the acquisition of blaNDM-6 by pEC4-NDM-6 and the rmtC 16S rRNA methylase gene by IncFIIY plasmids. Characterization of these plasmids further demonstrates that even very closely related plasmids may have acquired blaNDM genes by different mechanisms. These findings also illustrate the complex relationships between antimicrobial resistance genes, transposable elements, and plasmids and provide insights into the possible routes for transmission of blaNDM genes among species of the Enterobacteriaceae family

Exploring the measurement of markedness and its relationship with other linguistic variables

Antonym pair members can be differentiated by each word's markedness-that distinction attributable to the presence or absence of features at morphological or semantic levels. Morphologically marked words incorporate their unmarked counterpart with additional morphs (e.g., "unlucky" vs. "lucky"); properties used to determine semantically marked words (e.g., "short" vs. "long") are less clearly defined. Despite extensive theoretical scrutiny, the lexical properties of markedness have received scant empirical study. The current paper employs an antonym sequencing approach to measure markedness: establishing markedness probabilities for individual words and evaluating their relationship with other lexical properties (e.g., length, frequency, valence). Regression analyses reveal that markedness probability is, as predicted, related to affixation and also strongly related to valence. Our results support the suggestion that antonym sequence is reflected in discourse, and further analysis demonstrates that markedness probabilities, derived from the antonym sequencing task, reflect the ordering of antonyms within natural language. In line with the Pollyanna Hypothesis, we argue that markedness is closely related to valence; language users demonstrate a tendency to present words evaluated positively ahead of those evaluated negatively if given the choice. Future research should consider the relationship of markedness and valence, and the influence of contextual information in determining which member of an antonym pair is marked or unmarked within discourse

Long-term impacts of invasive species on a native top predator in a large lake system

1. Declining abundances of forage fish and the introduction and establishment of non-indigenous species have the potential to substantially alter resource and habitat exploitation by top predators in large lakes. 2. We measured stable isotopes of carbon (δ13C) and nitrogen (δ15N) in field-collected and archived samples of Lake Ontario lake trout (Salvelinus namaycush) and five species of prey fish and compared current trophic relationships of this top predator with historical samples. 3. Relationships between δ15N and lake trout age were temporally consistent throughout Lake Ontario and confirmed the role of lake trout as a top predator in this food web. However, δ13C values for age classes of lake trout collected in 2008 ranged from 1.0 to 3.9‰ higher than those reported for the population sampled in 1992. 4. Isotope mixing models predicted that these changes in resource assimilation were owing to the replacement of rainbow smelt (Osmerus mordax) by round goby (Neogobius melanostomus) in lake trout diet and increased reliance on carbon resources derived from nearshore production. This contrasts with the historical situation in Lake Ontario where δ13C values of the lake trout population were dominated by a reliance on offshore carbon production. 5. These results indicate a reduced capacity of the Lake Ontario offshore food web to support the energetic requirements of lake trout and that this top predator has become increasingly reliant on prey resources that are derived from nearshore carbon pathways

Coronary CT Angiography and 5-Year Risk of Myocardial Infarction.

BACKGROUND: Although coronary computed tomographic angiography (CTA) improves diagnostic certainty in the assessment of patients with stable chest pain, its effect on 5-year clinical outcomes is unknown. METHODS: In an open-label, multicenter, parallel-group trial, we randomly assigned 4146 patients with stable chest pain who had been referred to a cardiology clinic for evaluation to standard care plus CTA (2073 patients) or to standard care alone (2073 patients). Investigations, treatments, and clinical outcomes were assessed over 3 to 7 years of follow-up. The primary end point was death from coronary heart disease or nonfatal myocardial infarction at 5 years. RESULTS: The median duration of follow-up was 4.8 years, which yielded 20,254 patient-years of follow-up. The 5-year rate of the primary end point was lower in the CTA group than in the standard-care group (2.3% [48 patients] vs. 3.9% [81 patients]; hazard ratio, 0.59; 95% confidence interval [CI], 0.41 to 0.84; P=0.004). Although the rates of invasive coronary angiography and coronary revascularization were higher in the CTA group than in the standard-care group in the first few months of follow-up, overall rates were similar at 5 years: invasive coronary angiography was performed in 491 patients in the CTA group and in 502 patients in the standard-care group (hazard ratio, 1.00; 95% CI, 0.88 to 1.13), and coronary revascularization was performed in 279 patients in the CTA group and in 267 in the standard-care group (hazard ratio, 1.07; 95% CI, 0.91 to 1.27). However, more preventive therapies were initiated in patients in the CTA group (odds ratio, 1.40; 95% CI, 1.19 to 1.65), as were more antianginal therapies (odds ratio, 1.27; 95% CI, 1.05 to 1.54). There were no significant between-group differences in the rates of cardiovascular or noncardiovascular deaths or deaths from any cause. CONCLUSIONS: In this trial, the use of CTA in addition to standard care in patients with stable chest pain resulted in a significantly lower rate of death from coronary heart disease or nonfatal myocardial infarction at 5 years than standard care alone, without resulting in a significantly higher rate of coronary angiography or coronary revascularization. (Funded by the Scottish Government Chief Scientist Office and others; SCOT-HEART ClinicalTrials.gov number, NCT01149590 .)