Formation Mechanism of Iron-Rich Olivine: Experimental Constrains into Early Fluid-Assisted Hydration and Dehydration Processes on Asteroids

Iron-rich olivine is one of the major minerals in the matrices of unequilibrated ordinary (UOCs) and carbonaceous (CV, CK, CO) chondrites whose petrologic type is >3.1. There has been an extensive discussion in the literature as to the formation mechanism of these olivines; however, their origin is poorly understood. The formation of ferroan olivine during hydrothermal alteration has been demonstrated to be thermodynamically viable. The stability of ferroan olivine is highly dependent on several variables, including temperature, water/ rock (W/R) ratio, pressure, oxygen fugacity, and bulk rock composition. So far, hydrothermal alteration experiments have not been successful at forming FeO-rich olivines with the compositions and textures observed in the matrices of chondrites. Therefore, understanding the formation conditions of FeO-rich olivines remains a key problem to explain the effects of hydrothermal alteration on chondrite matrices

Clasts in the CM2 carbonaceous chondrite Lonewolf Nunataks 94101: evidence for aqueous alteration prior to complex mixing

Clasts in the CM2 carbonaceous chondrite Lonewolf Nunataks (LON) 94101 have been characterized using scanning and transmission electron microscopy and electron microprobe analysis to determine their degrees of aqueous alteration, and the timing of alteration relative to incorporation of clasts into the host. The provenance of the clasts, and the mechanism by which they were incorporated and mixed with their host material are also considered. Results show that at least five distinct types of clasts occur in LON 94101, of which four have been aqueously altered to various degrees and one is largely anhydrous. The fact that they have had different alteration histories implies that the main part of aqueous activity occurred prior to the mixing and assimilation of the clasts with their host. Further, the presence of such a variety of clasts suggests complex mixing in a dynamic environment involving material from various sources. Two of the clasts, one containing approximately 46 vol% carbonate and the other featuring crystals of pyrrhotite up to approximately 1 mm in size, are examples of unusual lithologies and indicate concentration of chemical elements in discrete areas of the parent body(ies), possibly by flow of aqueous solutions

Metamorphism on Ordinary Chondrite Parent Bodies: The Role of Fluids.

第3回極域科学シンポジウム/第35回南極隕石シンポジウム 11月30日（金） 国立国語研究所 2階講

The Fate of Primary Iron Sulfides in the CM1 Carbonaceous Chondrites: Effects of Advanced Aqueous Alteration on Primary Components

We have carried out a SEM-EPMA-TEM study to determine the textures and compositions of relict primary iron sulfides and their alteration products in a suite of moderately to heavily-altered CM1 carbonaceous chondrites. We observed four textural groups of altered primary iron sulfides: 1) pentlandite+phyllosilicate (2P) grains, characterized by pentlandite with submicron lenses of phyllosilicates, 2) pyrrhotite+pentlandite+magnetite (PPM) grains, characterized by pyrrhotite-pentlandite exsolution textures with magnetite veining and secondary pentlandite, 3) pentlandite+serpentine (PS) grains, characterized by relict pentlandite exsolution, serpentine, and secondary pentlandite, and 4) pyrrhotite+pentlandite+magnetite+serpentine (PPMS) grains, characterized by features of both the PPM and PS grains. We have determined that all four groups were initially primary iron sulfides, which formed from crystallization of immiscible sulfide melts within silicate chondrules in the solar nebula. The fact that such different alteration products could result from the same precursor sulfides within even the same meteorite sample further underscores the complexity of the aqueous alteration environment for the CM chondrites. The different alteration reactions for each textural group place constraints on the mechanisms and conditions of alteration with evidence for acidic environments, oxidizing environments, and changing fluid compositions (Ni-bearing and Si-Mg-bearing).Comment: 53 pages, 10 figures, 2 tables, appendix containing 3 additional figures and 5 additional table

Associations and within-group differences in physical characteristics and golf performance data in high-level amateur players

The aim of the present study was to assess the relationship between a comprehensive physical testing battery and golf performance, as quantified through a variety of previously determined usable metrics from launch monitor data. Twenty-six high level, amateur golfers undertook a series of physical assessments, including: anthropometry measurements, isometric mid-thigh pull (IMTP), isometric bench press, countermovement jump (CMJ), seated medicine ball throws for distance, and a seated thoracic rotation test. In addition, golf shot data was recorded in an indoor biomechanics laboratory, with a driver and 6-iron to quantify clubhead speed (CHS), ball speed, carry distance, and smash factor. Pearson’s r associative analysis showed that the strongest relationships between golf shot data was with the isometric bench press for the upper body (r values up to 0.76), and countermovement jump for the lower body (r values up to 0.82). In addition, median split analysis for physical performance data revealed that players who were able to exhibit greater maximal and explosive strength capabilities in the IMTP, isometric bench press and CMJ assessments, had significantly greater CHS (g range = 1.09-1.28; p < 0.05), ball speed (g range = 1.18-1.41; p < 0.05), carry distance (g range = 1.06-1.53; p < 0.05), and smash factor (g range = 0.81-1.17; p < 0.05). These data underscore the importance of superior physical capacity for golfers, especially for maximal force production in both the lower and upper body, as well as explosive force production for the lower body

Vertical flow in the Southern Ocean estimated from individual moorings

In this study, we demonstrate that oceanic vertical velocities can be estimated from individual mooring measurements, even for non-stationary flow. This result is obtained under three assumptions: i. weak diffusion (Péclet number ≫1), ii. weak friction (Reynolds number ≫1), and iii. small inertial terms (Rossby number ≪1). The theoretical framework is applied to a set of 4 moorings located in the Southern Ocean. For this site, the diagnosed vertical velocities are highly variable in time, their standard deviation being one-to-two orders of magnitude greater than their mean. We demonstrate that the time-averaged vertical velocities are largely induced by geostrophic flow, and can be estimated from the time-averaged density and horizontal velocities. This suggests that local time-mean vertical velocities are primarily forced by the time-mean ocean dynamics, rather than by e.g. transient eddies or internal waves. We also show that, in the context of these four moorings, the time-mean vertical flow is consistent with stratified Taylor column dynamics in the presence of a topographic obstacle

Stacking Defects in Synthetic and Meteoritic Hibonites: Implications for High-Temperature Processes in the Solar Nebula

Hibonite (CaAl12O19) is a primary, highly refractory phase occurring in many Ca-Al-rich inclusions (CAIs) from different chondrite groups, except CI chondrites. Hibonite is predicted to be one of the earliest minerals to condense during cooling of the solar nebula at higher temperatures than any other major CAI mineral. Therefore, hibonite has great potential to reveal the processes and conditions of the very early, high-temperature stages of the solar nebular evolution. Previous microstructural studies of hibonite in CAIs and their Wark-Lovering (WL) rims showed the presence of numerous stacking defects in hibonite. These defects are interpreted as the modification of the stacking sequences of spinel and Ca-containing blocks within the ideal hexagonal hibonite structure, as shown by experimental studies of reaction-sintered ceramic CaO-Al2O3 compounds. We performed preliminary experiments in the CaO-Al2O3-MgO system to understand the formation processes and conditions of defect-structured hibonite found in meteorites

Mineralogy and petrology of Comet Wild2 nucleus samples

Published versio

Interventions to promote patients and families' involvement in adult intensive care settings: a protocol for a mixed-method systematic review.

BACKGROUND: There has been an identified need for greater patient and family member involvement in healthcare. This is particularly relevant in an intensive care unit (ICU), as the family provides a key communicative and practical link between patient and clinician. Family members have been deemed a positive beneficial influence on ICU care and recovery processes, yet they themselves are often emotionally affected after discharge. There has been no standardised evidenced-based approach which explores research on family member involvement and the range and quality of contributions remain unclear. This project will undertake a systematic review to assess the evidence base for interventions designed to promote patient and family member involvement in adult intensive care settings and develop a comprehensive typology of interventions for use by clinicians, patients and carers. METHODS: The following databases will be searched without date restriction: MEDLINE, EMBASE and CINAHL, as well as the Cochrane Central Register of Controlled Trials, Joanna Briggs and Cochrane Libraries. Manual searches of recent back issues of leading ICU and patient experience journals will also be undertaken, as will the reference lists of included studies. Unpublished literature will be sought through grey literature databases, including GreyLit and OpenGrey. All evaluation studies that consider intervention activities to promote patient and family member involvement in adult ICUs will be included; all research designs will be eligible. We will seek to include studies that report on a mixture of relevant outcomes for patients and family members. Abstracts and papers will be independently screened by at least two members of the team to determine their inclusion. Included papers will be assessed for methodological rigour using a standard rating approach, which assesses 'quality of study' and 'quality of information'. Quality assessment will be completed by at least two members of the team. Data on interventions, evaluation methods and outcomes will be collated using a predetermined extraction table. These are likely to be heterogeneous in nature, which will mean that the review will follow a narrative approach to synthesis. DISCUSSION: The review will provide valuable and rigorous insight into the range and quality of interventions available to promote patient and family member involvement in ICU. This is the first step towards addressing the absence of a synthesis of research for this context, and will, in addition, develop a typology of available interventions that will help service users and clinicians make informed decisions about the approaches to patient and family member involvement which they might want to adopt. SYSTEMATIC REVIEW REGISTRATION: PROSPERO (CRD42018086325)