An EMP and TEM—AEM Study of Margarite, Muscovite and Paragonite in Polymetamorphic Metabauxites of Naxos Cyclades, Greece) and the Implications of Fine-scale Mica Interlayering and Multiple Mica Generations

Coexisting white micas and plagioclase were studied by electron microprobe (EMP), and transmission and analytical electron microscopy (TEM—AEM) in greenschist- to amphibolite-grade metabauxites from Naxos. The TEM—AEM studies indicate that sub-micron scale (0.01-1.0 μm thick) semicoherent intergrowths of margarite, paragonite and muscovite are common up to lower amphibolite conditions. If unrecognized, such small-scale mica interlayering can easily lead to incorrect interpretation of EMP data. Muscovite and paragonite in M2 greenschist-grade Naxos rocks are mainly relics of an earlier high-pressure metamorphism (M1). Owing to the medium-pressure M2 event, margante occurs in middle greenschist-grade metabauxites and gradually is replaced by plagioclase + corundum in amphibolite-grade metabauxites. The margarite displays minor IVAl3 VI(Fe3+, Al) Si-3 VI□--1 and considerable (Na, K) SiCa-1Al-1 substitution, resulting in up to 44 mol% paragonite and 6 mol % muscovite in solution. The compositional variation of muscovite is mainly described by VI(Fe2+, Mg) Si VI Al-1VI Al-1 and VI(Fe3+Al-1) exchanges, the latter becoming dominant at amphibolite grade, Muscovite is significantly richer in Fe than margarite or paragonite. Ca—Na—K partitioning data indicate that margarite commonly has a significantly higher Na/(Na+ K+Ca) value than coexisting muscovite or plagioclase. Exceptions are found in several greenschist-grade rocks, in which M1-formed mussovite may have failed to equilibrate with M2 margarite. The sluggishness of K-rich micas to recrystallize and adjust composidonally to changing P-T conditions is also reflected in the results of mus-covite-paragonite solvus thermometry. Chemical data for Ca—Na micas from this study and literature data indicate that naturally coexisting margarite—paragonite pairs display considerably less mutual solubility than suggested by experimental work. The variable and irregular Na partitioning between margarite and muscovite as observed in many metamorphic rocks could largely be related to opposing effects of pressure on Na solubility in margarite and paragonite and/or non-equilibrium between mica

Catharine Trotter and the Claims of Conscience

Although Catherine Trotter, later Cockburn, has begun to receive increased critical attention, the role of religious themes in her writing remains largely unexplored. A key tendency in critical accounts, in fact, has been to ally her with the secular contractarian philosophy of John Locke, whom she defended in print. Biographical evidence suggests, however, that Trotter was not unconcerned with religious questions; raised an Anglican, she converted to Catholicism in her youth and returned to the Church of England in her early thirties. Her later philosophical works remain preoccupied with theological issues, notably voluntarism. This article proposes that we can identify religious concerns in Trotter’s early plays by recognizing how her tragedies dramatize cases of conscience. Her characters often struggle to accept the binding nature of vows and question the power of private conscience to govern conduct. In The Unhappy Penitent (1701), the influence of the Catholic casuistical tradition is seen as Trotter casts doubt on the adequacy of private moral judgment, suggesting that individuals will judge right only when aided by an authoritative and external guide. Emphasizing the tragic consequences that follow from pursuing one’s interests, the dramas qualify assessments of Trotter that align her modernity with secularity

Emergency Registered Nurses’ Perceptions of Workplace Violence

Workplace violence (WPV) is a significant issue in today’s healthcare field, especially for nurses in the emergency department. WPV is defined by action of verbal abuse, threats, disruptive behavior, harassment, intimidation and/or physical abuse, or assault (Stene, Larson, Levy, & Dohlman, 2015). Emergency Department (ED) registered nurses (RNs) are in a prime position to experience WPV due to the nature and purpose of the emergency room. To address effectively the problem of WPV against RNs in the ED, it is crucial first to understand how nurses in this setting perceive WPV from patients and/or visitors. In a Level I Trauma Emergency Department in South Carolina, the “Emergency Registered Nurses’ Perceptions of Workplace Violence” survey was sent via electronic mail to RNs in the ED. Results from the questionnaire indicated that nurses are exposed to WPV on a regular basis, but often do not have effective tools to prevent a violent incident. Reducing and eliminating WPV are goals worth pursuing to provide successful safety measures for nurses and quality care for patients

Core Committee Publishes Guide To Electives

A handbook on electives for Home Economics students has been sent to press. The handbook, prepared by H o m e Economics Student Core Curriculum Committee, will be available for use in preclassification this quarter

Progressive Low-Grade Metamorphism of a Black Shale Formation, Central Swiss Alps, with Special Reference to Pyrophyllite and Margarite Bearing Assemblages

The unmetamorphosed equivalents of the regionally metamorphosed clays and marls that make up the Alpine Liassic black shale formation consist of illite, irregular mixed-layer illite/montmorillonite, chlorite, kaolinite, quartz, calcite, and dolomite, with accessory feldspars and organic material. At higher grade, in the anchizonal slates, pyrophyllite is present and is thought to have formed at the expense of kaolinite; paragonite and a mixed-layer paragonite/muscovite presumably formed from the mixed-layer illite/montmorillonite. Anchimetamorphic illite is poorer in Fe and Mg than at the diagenetic stage, having lost these elements during the formation of chlorite. Detrital feldspar has disappeared. In epimetamorphic phyllites, chloritoid and margarite appear by the reactions pyrophyllite + chlorite = chloritoid + quartz + H2O and pyrophyllite + calcite ± paragonite = margarite + quartz + H2O + CO2, respectively. At the epi-mesozone transition, paragonite and chloritoid seem to become incompatible in the presence of carbonates and yield the following breakdown products: plagioclase, margarite, clinozoisite (and minor zoisite), and biotite. The maximum distribution of margarite is at the epizone-mesozone boundary; at higher metamorphic grade margarite is consumed by a continuous reaction producing plagioclase. Most of the observed assemblages in the anchi-and epizone can be treated in the two subsystems MgO (or FeO)-Na2O−CaO−Al2O3−(KAl3O5−SiO2−H2O−CO2). Chemographic analyses show that the variance of assemblages decreases with increasing metamorphic grade. Physical conditions are estimated from calibrated mineral reactions and other petrographic data. The composition of the fluid phase was low in XCO2 throughout the metamorphic profile, whereas XCH4 was very high, particularly in the anchizone where aH2O was probably as low as 0.2. P-T conditions along the metamorphic profile are 1-2 kb/200-300 °C in the anchizone (Glarus Alps), and 5 kb/500-550 °C at the epi-mesozone transition (Lukmanier area). Calculated geothermal gradients decrease from 50 °C/km in the anchimetamorphic Glarus Alps to 30 °C/km at the epi-mesozone transition of the Lukmanier are

Shadow Standards and the Logic of Costs: Care, Stewardship, and Data in U.S. Community Health

This dissertation examines the delegation of responsibility for providing health care to particular categories of marginalized populations in the United States in the absence of a uniform and universal health care system. It explores how the U.S. federal government governs patient populations at a distance by mandating that healthcare providers collect, produce, and report on patient data. Drawing from eighteen months of ethnographic research in Massachusetts clinics for the homeless and the frail elderly between 2014-2015, I argue that when marginalized patients are unable to satisfy the neoliberal ideal of self-governance to maintain their health in cost-effective ways, providers are activated to bring them into compliance. Through the lens of political economic, science and technology studies, and critical medical anthropologies, I identified how reimbursement models and government funding requirements redesigned under the 2010 Affordable Care Act obligate health care providers to reframe the care they provide. Providers cultivate what I term the “logic of costs,” a budgetary lens for making care decisions that frames management of costs as essential to care. Data creation and reporting practices require providers to adopt a logic of costs, as such data informs whether their clinics will be deemed effective and the clinics’ funding reauthorized. I trace the incongruities between actual care practices and the metrics that clinics end up recording and submitting to represent their work and their patients. I argue that this work is made possible through the creation of “shadow standards,” unofficial, undocumented, and yet routinized healthcare practices that make the creation and reporting of health data possible, even when providers do not have the resources to comply

216 Jewish Hospital of St. Louis

https://digitalcommons.wustl.edu/bjc_216/1179/thumbnail.jp

The Effects of Retrograde Reactions and of Diffusion on 40Ar-39Ar Ages of Micas

The effects of metamorphic reactions occurring during decompression were explored to understand their influence on the 40Ar-39Ar ages of micas. Monometamorphic metasediments from the Lepontine Alps (Switzerland) reached lower amphibolite facies during the Barrovian metamorphism related to the collision between European and African (Adria) continental plates. Mineral assemblages typically composed of garnet, plagioclase, biotite, muscovite and paragonite (or margarite) were screened for petrological equilibrium, to focus on samples that record a minimum degree of retrogression. X-ray diffraction data indicate that some mineral separates prepared for 40Ar-39Ar stepwise heating analysis are monomineralic, whereas others are composed of two white micas (muscovite with paragonite or margarite), or biotite and chlorite. In monomineralic samples 37Ar/39Ar and 38Ar/39Ar (proportional to Ca/K and Cl/K ratios) did not change and the resulting ages can be interpreted unambiguously. In mineral separates containing two white micas, Ca/K and Cl/K ratios were variable, reflecting non-simultaneous laboratory degassing of the two heterochemical Ar reservoirs. These ratios were used to identify each Ar reservoir and to unravel the age. In a chlorite-margarite-biotite calcschist equilibrated near 560°C and 0·65 GPa, biotite, margarite, and muscovite all yield ages around 18 Ma. At slightly higher grade (560-580°C, 0·8-0·9 GPa), the assemblage muscovite-paragonite-plagioclase is in equilibrium and remains stable during retrogression. In this case, muscovite and paragonite yield indistinguishable ages around 16·5 Ma. Above 590°C, paragonite was mostly consumed to form plagioclase >590°C, whereby the relict mica yields an age up to 5·6 Ma younger than muscovite. This partial or total resetting of the Ar clock in paragonite is interpreted to reflect plagioclase growth during decompression. Where biotite is present within this same assemblage, it systematically yields a younger age than muscovite, by 0·5-2 Ma. However, these biotites all show small amounts of retrograde chlorite formation. We conclude that even very minor chloritization of biotite is apparently a more effective process than temperature in resetting the Ar clock, as is the formation of plagioclase from paragonite decomposition. Multi-equilibrium thermobarometry is an excellent means to ensure that equilibrium in investigated samples is preserved, and this helps to obtain geologically meaningful metamorphic ages. However, even samples passing such equilibrium tests may still show retrograde effects that affect the Ar retention of micas. A more robust interpretation of such 40Ar-39Ar results may require use of a second geochronometer, such as U-Pb on monazit