Mantle plume capture, anchoring, and outflow during Galápagos plume-ridge interaction

Compositions of basalts erupted between the main zone of Galápagos plume upwelling and adjacent Galápagos Spreading Center (GSC) provide important constraints on dynamic processes involved in transfer of deep-mantle-sourced material to mid-ocean ridges. We examine recent basalts from central and northeast Galápagos including some that have less radiogenic Sr, Nd, and Pb isotopic compositions than plume-influenced basalts (E-MORB) from the nearby ridge. We show that the location of E-MORB, greatest crustal thickness, and elevated topography on the GSC correlates with a confined zone of low-velocity, high-temperature mantle connecting the plume stem and ridge at depths of ∼100 km. At this site on the ridge, plume-driven upwelling involving deep melting of partially dehydrated, recycled ancient oceanic crust, plus plate-limited shallow melting of anhydrous peridotite, generate E-MORB and larger amounts of melt than elsewhere on the GSC. The first-order control on plume stem to ridge flow is rheological rather than gravitational, and strongly influenced by flow regimes initiated when the plume was on axis (>5 Ma). During subsequent northeast ridge migration material upwelling in the plume stem appears to have remained “anchored” to a contact point on the GSC. This deep, confined NE plume stem-to-ridge flow occurs via a network of melt channels, embedded within the normal spreading and advection of plume material beneath the Nazca plate, and coincides with locations of historic volcanism. Our observations require a more dynamically complex model than proposed by most studies, which rely on radial solid-state outflow of heterogeneous plume material to the ridge.We thank Galápagos National Park authorities and CDRS for permitting fieldwork in Galápagos. D. Villagomez and D. Toomey generously shared their extensive seismic data set for Galápagos, and D. McKenzie kindly provided help with temperature calculations. End-member compositions of Galápagos mantle reservoirs in Figure 4 were estimated from principal component analysis; data related to these calculations are available in the supporting information. We are grateful to Kaj Hoernle and two anonymous reviewers for their constructive comments on an earlier version of this manuscript. The research was funded by the University of Cambridge, Geological Society of London, NERC (RG57434), and NSF (EAR 0838461, EAR 0944229, and EAR-11452711).This is the final published version of the article. It first appeared at http://dx.doi.org/10.1002/2015GC00572

The stereotypic behaviours of children with Autism Spectrum Disorders in structured and unstructured physical activity

The purpose was to study and observe children with Autism Spectrum Disorder (ASD) in structured and unstructured physical activity and determine how these types of physical activity settings affected the stereotypical behaviours of the children with ASD. This was done simultaneously alongside a research study whose aim was to implement a fundamental movement skill program for children with ASD. Participants included one five-year-old and two seven-year-olds. A single case study design was used for this study. Data were collected periodically by systematic observation and field notes during an eight week period in the fall school semester. Once a week, for eight weeks, participants would attend the program and take part in both structured physical activity in the form of an obstacle course, and unstructured physical activity in the form of free play. The observer watched the children participate in physical activity and recorded instances of the participants' stereotypical behaviours. A plus (+) sign indicated the presence of stereotypical behaviour and a minus (-) sign indicated the absence of stereotypical behaviour. The chart focused on 23 behaviours and was adapted from a study by Levinson and Reid (1993). It was found that the participants' stereotypical behaviours were seen less in the structured physical activity than in the unstructured free play physical activity; however the participants varied in their levels of decrease. These results are consistent with previous literature that show that a structured physical activity program can reduce the presence of stereotypical behaviors in children with ASD. These results indicate that children with ASD will benefit most from physical activity programs that include a structured physical activity aspect

Source lithology of the Galápagos plume

We have measured the contents of Ni, Ca, and Mn in olivine phenocrysts from volcanoes in the Galápagos archipelago to infer the mantle source lithologies. Results show that peridotite is the dominant source lithology for Fernandina, Floreana, Genovesa, Marchena, Pinta, Wolf Island, and Darwin Island. These volcanoes largely characterize the PLUME, WD, FLO and DUM Nd, Sr, and Pb isotopic endmembers of Harpp and White (2001). Only a minor pyroxenite component contributes to Fernandina and Floreana. Peridotite is also the dominant source lithology for Volcan Wolf, Alcedo, and Cerro Azul, and that these have isotopic compositions that can be defined by mixing of the 4 endmembers. Peridotite is therefore the dominant source lithology of the Galápagos plume. However, pyroxenite melting is significant in two spatially separated domains which are also isotopically distinct: Roca Redonda, Volcan Ecuador, Sierra Negra in the enriched western part of the archipelago and Volcan Darwin, Santiago, Santa Cruz, and Santa Fe in the depleted east. An implication is that the western and eastern pyroxenite domains likely represent two separate bodies of recycled crust within the Galápagos mantle plume. Isotopically enriched and depleted domains of the archipelago melted from both peridotite and pyroxenite, and there is no relationship between source lithology and its isotopic characteristics. The identification of peridotite source melting in volcanoes with isotopic characteristics that have been attributed to recycled crust points to the importance of mixing in OIB genesis, in agreement with studies on the Canary Islands.M.S.Includes bibliographical referencesby Christopher Allen Vidit

Lithological structure of the Galápagos Plume

We have measured Ni, Ca, and Mn in olivine phenocrysts from volcanoes in the Galápagos Archipelago to infer the mantle source lithologies. Results show that peridotite is the dominant source lithology for Fernandina, Floreana, Genovesa, Wolf Island, and Darwin Island. These volcanoes largely characterize the PLUME, WD, FLO, and DUM Nd, Sr, and Pb isotopic endmembers of Harpp and White (2001). Volcan Wolf, Alcedo, Marchena, and Cerro Azul, also produced from the melting of peridotite sources, have isotopic compositions that can be defined by mixing of the four isotopic endmembers. Our analysis suggests that peridotite was present in the sources of the volcanoes covered in this study and therefore is the dominant source lithology of the Galápagos plume. Pyroxenite melting is generally focused in two isotopically distinct domains: Roca Redonda, Volcan Ecuador, and Sierra Negra in the enriched western part of the archipelago and Santiago, Santa Cruz, and Santa Fe in the depleted east. One implication of this finding is that the Western and Eastern Pyroxenite Domains represent two separate bodies of recycled crust within the Galápagos mantle plume. Furthermore, both isotopically enriched and depleted domains of the archipelago were generated from mixtures of peridotite and pyroxenite. This suggests that there is no relationship between the source lithology of the Galápagos plume and its isotopic characteristics. The identification of peridotite‐source melting in volcanoes with isotopic characteristics that have been attributed to recycled crust points to the importance of mixing in OIB genesis, consistent with studies in the Canary Islands

Treatment Sequencing Patterns in Medicare-Enrolled Patients with Multiple Myeloma

Abstract Introduction: Over the last decade, several novel therapies have been approved for multiple myeloma (MM) leading to significant improvement in the prognosis of MM patients. MM patients are often treated with multiple lines of therapy as relapse occurs. With the numerous options of therapeutic agents and novel combinations of regimens, the treatment for MM has become more complicated. However, little is known regarding the treatment sequencing patterns for Medicare patients with MM. In this study, we described the use of drug regimens by lines of therapy and characterized treatment sequences in Medicare patients with MM. Methods: Using a validated algorithm (Princic et al. Blood 2015;126:4521), we identified adult MM patients (≥ 18 years old) in 2008-2011 from the Centers for Medicare &amp; Medicaid Services 100% Hematologic Cancer file (2007-2012) who began first-line (1L) treatment. Patients who advanced to second-line (2L), third-line (3L), and fourth-line (4L) were identified if a 90 day gap in all treatments was observed or when a drug was added to a regimen &gt;90 days after the line index date. Drug regimens were based on National Comprehensive Cancer Network MM treatment guidelines and were identified using National Drug Code and Healthcare Common Procedure Coding System codes. Patients were included in the study if they received monotherapy, doublets, or triplets at 1L. The study period was from the 1L initiation date to the earliest of death, disenrollment from Medicare Parts A, B, and D coverage, receipt of treatments other than the above-mentioned drug regimens, or December, 31, 2012. We described the distribution of type of drug regimens by lines of therapy, overall and by age defined at MM index date, and characterized treatment sequencing patterns for patients who advanced to 2L, 3L, and 4L by type of drug regimens in the prior line of therapy, respectively. Results: In total, 12563 MM patients initiated 1L therapy. Of these, 9% were aged 18-64 years (enrolled in Medicare due to disabilities), 42% aged 65-74 years, and 49% aged ≥ 75 years. Most patients were white (78%) and more than half were female (53%). We identified 5647 (45%), 2243 (18%), and 773 (6%) patients who advanced to 2L, 3L, and 4L, respectively. Overall, doublets were the most common 1L regimen (62%), followed by monotherapy (21%) and triplets (17%). Most common treatments for monotherapy in 1L were dexamethasone (52%), lenalidomide (21%), and bortezomib (17%). The pattern was similar among patients who advanced to a 2L, 3L, or 4L, respectively, though more triplets were used at advanced lines. For 1L therapy, only 12% of patients aged ≥ 75 years received triplets, in contrast to &gt;20% of triplet use in 3L and 4L respectively (Table). Of patients who received monotherapy in 1L and advanced to 2L, 37% continued monotherapy and 63% switched to more dense regimens (doublets, 53%; triplets 10%). Of patients who received doublets in 1L and advanced to 2L, 58% continued doublets, 22% switched to triplets, and 20% to monotherapy. Of patients who received triplets in 1L and advanced to 2L, 26% continued triplets and 74% switched to less dense regimens (doublets, 47%; monotherapy, 27%). Treatment sequencing patterns were similar for patients who advanced to 3L and 4L with monotherapy or doublets in prior lines, while the proportion of patients who repeated triplets increased to about 32% in 3L and 37% in 4L (Figure). Conclusions: Among Medicare patients with MM, doublets were the most frequently used regimens across all lines of therapy, while triplets were used in more advanced lines. Patients on monotherapy or doublets were more likely to retain their treatment pattern when they advance to the next line of therapy, while those on triplet regimen were more likely to switch to a less dense regimen when they advance to their next line of therapy. Fewer patients of older age (75+ years) were prescribed triplet therapies, however triplet use in this patient group increases in more advanced lines. These results provide a baseline description of treatment patterns from which we will be able to benchmark the impact of the recent introduction of novel agents and their use in elderly MM patients. Further studies assessing the comparative effectiveness and benefit-risk of treatment sequences are warranted. Figure Figure. Disclosures Yusuf: Amgen Inc.: Employment, Equity Ownership. Vidito:Amgen Inc.: Employment, Equity Ownership. Mezzi:Amgen Inc.: Employment, Equity Ownership. Werther:Amgen Inc.: Employment, Equity Ownership. </jats:sec

A Calcium-in-Olivine Geohygrometer and its Application to Subduction Zone Magmatism

High-precision electron microprobe analyses were obtained on olivine grains from Klyuchevskoy, Shiveluch and Gorely volcanoes in the Kamchatka Arc; Irazu, Platanar and Barva volcanoes of the Central American Arc; and mid-ocean ridge basalt (MORB) from the Siqueiros Transform. Calcium contents of these subduction zone olivines are lower than those for olivines from modern MORB, Archean komatiite and Hawaii. A role for magmatic H2O is likely for subduction zone olivines, and we have explored the suggestion of earlier workers that it has affected the partitioning of CaO between olivine and silicate melt. We provide a provisional calibration of DCaO Ol/L as a function of magmatic MgO and H2O, based on nominally anhydrous experiments and minimally degassed H2O contents of olivine-hosted melt inclusions. Application of our geohygrometer typically yields 3–4 wt % magmatic H2O at the Kamchatka and Central American arcs for olivines having 1000 ppm Ca, which agrees with H2O maxima from melt inclusion studies; Cerro Negro and Shiveluch volcanoes are exceptions, with about 6% H2O. High-precision electron microprobe analyses with 10–20 lm spatial resolution on some olivine grains from Klyuchevskoy and Shiveluch show a decrease in Ca content from the core centers to the rim contacts, and a sharp increase in Ca in olivine rims. We suggest that the zoning of Ca in olivine from subduction zone lavas may provide the first petrological record of temporal changes that occur during hydration of the mantle wedge and dehydration during ascent, and we predict olivine H2O contents that can be tested by secondary ionization mass spectrometry analysis