scholarly journals Olivine in komatiite records origin and travel from the deep upper mantle

Geology ◽  
2021 ◽  
Author(s):  
Allan Wilson ◽  
Robert Bolhar
Keyword(s):  
High Pressure ◽  
Upper Mantle ◽  
Direct Evidence ◽  
Core Mantle Boundary ◽  
Mantle Evolution ◽  
Mineral Inclusions ◽  
Naturally Occurring ◽  
Deep Mantle ◽  
Earth’S Early Mantle ◽  
Insight Into

The deep upper mantle is the main source of high-temperature magmatism, but the only known naturally occurring samples of high-pressure mantle constituents are mineral inclusions in diamonds. Trace elements in olivine crystals from the 3.33 Ga Commondale Greenstone Belt in South Africa reveal that these crystals formed in the deep upper mantle as high-pressure phenocrysts, and some perhaps even formed in the mantle transition zone (410–600 km) where they began as wadsleyite. The crystals were entrained within ascending komatiite magma and conveyed to the surface. The olivine crystals have the highest contents of Al2O3 (0.3 wt%) recorded in any terrestrial olivine, which is indicative of formation at high pressure. The deep mantle gave rise to Archean komatiites, extraordinarily hot magmas (up to 1700 °C), which provide insight into Earth’s early mantle evolution and the formation of most ancient continental and oceanic crust. In spite of extensive research since their discovery over 50 years ago, the origins of komatiites have remained contentious. Plumes—thermochemical instabilities originating at the core-mantle boundary—are the most likely source, but no direct evidence of a deep mantle origin of komatiite has yet been recognized.

scholarly journals Thermobarometry of Diamond Inclusions: Evidence Mantle Evolution beneath Siberian Craton and Archean Cratons Worldwide.

2021 ◽  
Author(s):  
Igor Ashchepkov ◽  
Alla Logvinova ◽  
Zdislav Spetsius ◽  
Hilary Downes
Keyword(s):  
High Pressure ◽  
High Temperature ◽  
Middle Part ◽  
East European ◽  
Mantle Evolution ◽  
Mineral Inclusions ◽  
Amazonian Craton ◽  
Partial Melts ◽  
Continental Growth ◽  
Diamond Inclusions

Thermobarometric calculations for mineral inclusions in diamonds provide a systematic comparison of PTXFO2 conditions for different cratons worldwide, using a database of 4440 mineral EPMA analyses. Beneath all cratons, the cold branch of the mantle geotherm (35-32 mWm−2) relates to the sub-Ca garnets and rarely omphacitic diamond inclusions, referring to major continental growth events in Archean. High-temperature plume-related geotherms are common in Proterozoic kimberlites such as Premier, Mesozoic – Roberts Victor etc. and are common in Slave and Siberian cratons. In mobile belts: Limpopo, Magondi, Ural Ural, Khapchan belts and in the marginal parts of cratons like Kimberly Australia pyroxenitic and eclogitic pyroxenes and garnets prevail. The pyropes in the mobile belts are more Fe- and Ca-rich, in central parts of cratons, the peridotitic associations with sub- Ca pyropes prevail. The accretionary complexes like Khapchan and Magondi belts a thick eclogite-pyroxenite lens is highly diamondiferous. Comparison by minerals shows that the PT estimates for clinopyroxenes and orthopyroxene from peridotites and eclogites are representing mainly the middle part of the sub-lithospheric mantle while garnets gives more high-pressure estimates. refer to eclogites and reflect the processes of the differentiation during migration of partial melts. This produces the trends of joint decreasing Mg’ and pressures. The PT for the chromites reflect conditions just above the lithosphere-asthenosphere boundary and mainly were formed due to interaction with the hydrous plume protokimberlite melts. Archean diamond inclusions from Wawa province Canada are represented by Ca-enrich pyropes giving low-temperature conditions. Inclusions from younger kimberlites in Superior and Slave (and Siberian and East European ) cratons show complex high-temperature geotherms due to plumes influence. Peridotite garnets beneath the Amazonian craton indicate complex layering in the lithosphere base and a pyroxene layer in the middle part of SCLM. Diamond inclusions from the Kimberley craton of Australia show the greatest variations in the temperatures and composition.

A reactive center loop–based prediction platform to enhance the design of therapeutic SERPINs

2021 ◽  
Vol 118 (45) ◽  
pp. e2108458118
Author(s):  
Wariya Sanrattana ◽  
Thibaud Sefiane ◽  
Simone Smits ◽  
Nadine D. van Kleef ◽  
Marcel H. Fens ◽  
...  
Keyword(s):  
Cleavage Site ◽  
Serine Proteases ◽  
Protein C ◽  
Activated Protein C ◽  
Reactive Center Loop ◽  
Physiological Processes ◽  
Naturally Occurring ◽  
Reactive Center ◽  
Insight Into

Serine proteases are essential for many physiological processes and require tight regulation by serine protease inhibitors (SERPINs). A disturbed SERPIN–protease balance may result in disease. The reactive center loop (RCL) contains an enzymatic cleavage site between the P1 through P1’ residues that controls SERPIN specificity. This RCL can be modified to improve SERPIN function; however, a lack of insight into sequence–function relationships limits SERPIN development. This is complicated by more than 25 billion mutants needed to screen the entire P4 to P4’ region. Here, we developed a platform to predict the effects of RCL mutagenesis by using α1-antitrypsin as a model SERPIN. We generated variants for each of the residues in P4 to P4’ region, mutating them into each of the 20 naturally occurring amino acids. Subsequently, we profiled the reactivity of the resulting 160 variants against seven proteases involved in coagulation. These profiles formed the basis of an in silico prediction platform for SERPIN inhibitory behavior with combined P4 to P4’ RCL mutations, which were validated experimentally. This prediction platform accurately predicted SERPIN behavior against five out of the seven screened proteases, one of which was activated protein C (APC). Using these findings, a next-generation APC-inhibiting α1-antitrypsin variant was designed (KMPR/RIRA; / indicates the cleavage site). This variant attenuates blood loss in an in vivo hemophilia A model at a lower dosage than the previously developed variant AIKR/KIPP because of improved potency and specificity. We propose that this SERPIN-based RCL mutagenesis approach improves our understanding of SERPIN behavior and will facilitate the design of therapeutic SERPINs.

‘Who decided this?’: Negotiating epistemic and deontic authority in systemic family therapy training

2022 ◽  
pp. 146144562110374
Author(s):  
Katerina Nanouri ◽  
Eleftheria Tseliou ◽  
Georgios Abakoumkin ◽  
Nikos Bozatzis
Keyword(s):  
Adult Education ◽  
Family Therapy ◽  
Conversation Analysis ◽  
Epistemic Authority ◽  
Family Therapy Training ◽  
Naturally Occurring ◽  
Therapy Training ◽  
Systemic Family Therapy ◽  
Deontic Authority ◽  
Insight Into

In this article we illustrate how trainers and trainees negotiate epistemic and deontic authority within systemic family therapy training. Adult education principles and postmodern imperatives have challenged trainers’ and trainees’ asymmetries regarding knowledge (epistemics) and power (deontics), normatively implicated by the institutional training setting. Up-to-date, we lack insight into how trainers and trainees negotiate epistemic and deontic rights in naturally occurring dialog within training. Drawing from discursive psychology and conversation analysis, we present an analysis of eight transcribed, videotaped training seminars from a systemic family therapy training program, featuring three trainers and eleven trainees. Our analysis highlights the dilemmatic ways in which participants resist and affirm the normatively implicated trainers’ deontic and epistemic authority. Trainers are shown as mitigating directives and trainees as resisting them, with both displaying (not)knowing, while attending to concerns about (a)symmetry. We discuss our findings’ implications for systemic family therapy training.

scholarly journals QTL analysis of self-selected macronutrient diet intake: fat, carbohydrate, and total kilocalories

2002 ◽  
Vol 11 (3) ◽  
pp. 205-217 ◽  
Author(s):  
Brenda K. Smith Richards ◽  
Brenda N. Belton ◽  
Angela C. Poole ◽  
James J. Mancuso ◽  
Gary A. Churchill ◽  
...  
Keyword(s):  
Body Weight ◽  
Qtl Analysis ◽  
Genetic Basis ◽  
Body Weight Gain ◽  
Macronutrient Intake ◽  
Naturally Occurring ◽  
Trait Locus ◽  
Diet Intake ◽  
Insight Into ◽  
Protein Quantitative Trait Locus

The present study investigated the inheritance of dietary fat, carbohydrate, and kilocalorie intake traits in an F2 population derived from an intercross between C57BL/6J (fat-preferring) and CAST/EiJ (carbohydrate-preferring) mice. Mice were phenotyped for self-selected food intake in a paradigm which provided for 10 days a choice between two macronutrient diets containing 78/22% of energy as a composite of either fat/protein or carbohydrate/protein. Quantitative trait locus (QTL) analysis identified six significant loci for macronutrient intake: three for fat intake on chromosomes (Chrs) 8 ( Mnif1), 18 ( Mnif2), and X ( Mnif3), and three for carbohydrate intake on Chrs 17 ( Mnic1), 6 ( Mnic2), and X ( Mnic3). An absence of interactions among these QTL suggests the existence of separate mechanisms controlling the intake of fat and carbohydrate. Two significant QTL for cumulative kilocalorie intake, adjusted for baseline body weight, were found on Chrs 17 ( Kcal1) and 18 ( Kcal2). Without body weight adjustment, another significant kcal locus appeared on distal Chr 2 ( Kcal3). These macronutrient and kilocalorie QTL, with the exception of loci on Chrs 8 and X, encompassed chromosomal regions influencing body weight gain and adiposity in this F2 population. These results provide new insight into the genetic basis of naturally occurring variation in nutrient intake phenotypes.

Distributed Cognition and Temporal Knowledge in League of Legends

2018 ◽  
Vol 10 (1) ◽  
pp. 23-41
Author(s):  
Jason Ginsberg Reitman
Keyword(s):  
High Pressure ◽  
Video Game ◽  
Distributed Cognition ◽  
Temporal Information ◽  
University Of California ◽  
Competitive Environment ◽  
The University ◽  
League Of Legends ◽  
Insight Into

Elite video game competition provides a setting for studying how digitally connected teams handle massive amounts of information that no individual could manage on their own. This article discusses observations of the University of California, Irvine's scholarship League of Legends teams' practices and competitions from fall 2016 through spring 2017. The observations explore the nature of distributed cognition of time and temporal information in a high-pressure, competitive environment. The capacity and strategies of these teams to maintain high levels of coordination, while sitting at desktops for hours at a time, can provide insight into how other kinds of teams might learn to collaborate skillfully in networked settings.

scholarly journals A Chemometrics Approach Comparing Volatile Changes during the Shelf Life of Apple Juice Processed by Pulsed Electric Fields, High Pressure and Thermal Pasteurization

Foods ◽  
2018 ◽  
Vol 7 (10) ◽  
pp. 169 ◽  
Author(s):  
Biniam Kebede ◽  
Pui Lee ◽  
Sze Leong ◽  
Vidya Kethireddy ◽  
Qianli Ma ◽  
...  
Keyword(s):  
High Pressure ◽  
Shelf Life ◽  
Electric Fields ◽  
Pulsed Electric Fields ◽  
High Pressure Processing ◽  
Life Changes ◽  
Processing Technologies ◽  
Promotion Strategies ◽  
Thermal Pasteurization ◽  
Insight Into

High-Pressure Processing (HPP) and Pulsed Electric Fields (PEF) processing technologies are being used increasingly on a commercial basis, with high-quality labelled fruit juices being one of the most important promotion strategies. Quality-related enzymes, which might still be active after HPP and PEF pasteurization, can cause undesirable aroma changes during storage. This study investigated volatile changes during the shelf life of PEF (15.5 kV/cm and specific energy of 158 kJ/L), HPP (600 MPa for 3 min), and thermally (72 °C for 15 s) pasteurized Jazz apple juices—up to five weeks. To have an increased insight into the volatile changes, an integrated instrumental (GC-MS) and data analysis (chemometrics) approach was implemented. Immediately after pasteurization, PEF processing resulted a better retention of odor-active volatiles, such as (E)-2-hexenal and hexyl acetate, whereas thermal processing lowered their amount. During refrigerated storage, these volatiles have gradually decreased in all processed juices. By the end of storage, the amount of these aroma relevant volatiles appears to still be higher in PEF and HPP pasteurized juices compared to their conventional counterparts. This study demonstrated the potential of advanced chemometric approaches to obtain increased insight into complex shelf life changes.

scholarly journals Exsolution Lamellae in Orthopyroxene of Lherzolite from the Pauza Ultramafic Rocks, Ne Iraq: Evidence of Deep Mantle Signature in the Zagros Suture Zone

2013 ◽  
Vol 2 (9) ◽  
pp. 102-115
Author(s):  
Yousif Osman Mohammad ◽  
Nabaz Rashid Hama Aziz
Keyword(s):  
High Pressure ◽  
Upper Cretaceous ◽  
Suture Zone ◽  
Ultramafic Rocks ◽  
Chromian Spinel ◽  
Spinel Peridotite ◽  
Incongruent Melting ◽  
Fine Grained ◽  
Ultra High Pressure ◽  
Deep Mantle

The Pauza ultramafic body is part of Upper Cretaceous Ophiolitic massifs of the Zagros Suture Zone, NE Iraq. The present study reveals evidence of Ultra-high pressure (UHP), and deep mantle signature of these peridotites in the Zagros Suture Zone throughout the observation of backscattered images and micro analyses which have been performed on orthopyroxen crystals in lherzolite of Pauza ultramafic rocks.Theorthopyroxen shows abundant exsolution lamellae of coarse unevenly distributed clinopyroxene coupled with the submicron uniformly distributed needles of Cr-spinel. The observed clusters of Opx–Cpx–Spl represent the decompression products of pyrope-rich garnet produced as a result of the transition from ultra-high pressure garnet peridotite to low-pressure spinel peridotite (LP). Neoblastic olivine (Fo92 – 93) with abundant multi-form Cr- spinel inclusions occurs as a fine-grained aggregate around orthopyroxene, whereas coarse olivine (Fo90-91) free from chromian-spinel is found in matrix. The similarity of the Cr-spinel lamellae orientations in both olivine and orthopyroxene, moreover, the enrichments of both Cr and Fe3+ in the Cr-spinel inclusions in neoblastic olivine relative to Cr-spinel lamellae in orthopyroxene, suggest that spinel inclusions in olivine have been derived from former Cr-spinel lamellae in orthopyroxene. Neoblastic olivine is formed by reaction of silica-poor ascending melt and orthopyroxene. It is inferred that the olivines with multi-form spinel inclusions has been formed by incongruent melting of pre-existing spinel lamellae-rich orthopyroxene.

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