312 research outputs found
Clashing Consciousness: A Cure for Modern Medicine's Epistemic Privilege
In this paper, I consider practical strategies for resolving the epistemic injustice that ill persons face when seeking medical treatment. My arguments will expand upon those initially made by Havi Carel and Ian James Kidd in âEpistemic Injustice in Healthcare: A Philosophical Analysis.â My approach to this problem is twofold. First, I will demonstrate how the phenomenological toolkit, as it currently stands, emphasizes the patientâs experience and leaves the doctorâs experience unadjusted. After this, I will explain how the toolkit can be improved to include the doctorâs perspective
Ultrahigh-temperature osumilite gneisses in southern Madagascar record combined heat advection and high rates of radiogenic heat production in a long-lived high-T orogen
We report the discovery of osumilite in ultrahighâtemperature (UHT) metapelites of the Anosyen domain, southern Madagascar. The gneisses equilibrated at ~930°C/0.6 GPa. Monazite and zircon UâPb dates record 80 Ma of metamorphism. Monazite compositional trends reflect the transition from prograde to retrograde metamorphism at 550 Ma. Eu anomalies in monazite reflect changes in fO_2 relative to quartzâfayaliteâmagnetite related to the growth and breakdown of spinel. The ratio Gd/Yb in monazite records the growth and breakdown of garnet. High rates of radiogenic heat production were the primary control on metamorphic grade at the regional scale. The short duration of prograde metamorphism in the osumilite gneisses (<29 ± 8 Ma) suggests that a thin mantle lithosphere (<80 km) or advective heating may have also been important in the formation of this highâT, lowâP terrane
Toward Intelligent Machine Learning Algorithms
Coordinated Science Laboratory was formerly known as Control Systems LaboratoryNational Science Foundation / NSF IST-85-11170Office of Naval Research / N00014-82-K-0186Defense Advanced Research Projects Agency / N00014-87-K-0874Texas Instruments, Inc
Focused radiogenic heating of middle crust caused ultrahigh temperatures in southern Madagascar
Internal heating can cause melting, metamorphism, and crustal weakening in convergent orogens. This study evaluates the role of radiogenic heat production (RHP) in a Neoproterozoic ultrahigh-temperature metamorphic (UHTM) terrane exposed in southern Madagascar. Monazite and zircon geochronology indicates that the Paleoproterozoic Androyen and Anosyen domains (i) collided with the oceanic Vohibory Arc at ~630âMa, (ii) became incorporated into the Gondwanan collisional orogen by ~580âMa, and (iii) were exhumed during crustal thinning at 525â510âMa. Ti-in-quartz and Zr-in-rutile thermometry reveals that UHTM occurred over >20,000âkm^2, mostly within the Anosyen domain. Assuming that U, Th, and K contents of samples from the field area are representative of the middle to lower crust during orogenesis, RHP was high enoughâlocally >5âÎŒW/m^3âto cause regional UHTM in <60 Myr. We conclude that, due in large part to the stability and insolubility of monazite at high crustal temperatures, RHP was the principal heat source responsible for UHTM, obviating the need to evoke external heat sources. Focused RHP probably thermally weakened portions of the middle crust, gravitationally destabilizing the orogen and facilitating thinning via lateral extrusion of hot crustal sections
Progress on the development of a single line of sight x-ray framing camera
High-speed micro-strip micro-channel plate (MCP) x-ray framing cameras are a well established diagnostic for laser plasma experiments. Each frame acquired with these devices requires a separate image, and with most reasonable x-ray optics, a separate line of sight, causing potential parallax problems. Gated image tubes have a single line of sight capability, but the conventional designs have not been effectively extended to the short gating times of the micro-strip-line MCP camera. A hybrid camera combining image tube and micro-strip-line MCP technology has been under development at LLNL in collaboration with UR/LLE, and KENTECH Instruments. The key feature of this single line of sight (SLOS) hybrid image tube is a deflection assembly that continuously divides the electrons from a single photocathode x-ray image into a set of four electron images. Temporal gating of these images is carried out using a microstripline microchannel plate framing camera module positioned at the image plane of the electron tube. Characterization measurements performed using both X-rays from a Manson source and from laser generated plasmas, will be presented. Some implementation improvements will be discussed. The results will be compared to simulations carried out using the charged particle optics code SIMION. Various dissector designs were simulated in an effort to improve the image quality of the system
Ultrahigh-temperature osumilite gneisses in southern Madagascar record combined heat advection and high rates of radiogenic heat production in a long-lived high-T orogen
We report the discovery of osumilite in ultrahighâtemperature (UHT) metapelites of the Anosyen domain, southern Madagascar. The gneisses equilibrated at ~930°C/0.6 GPa. Monazite and zircon UâPb dates record 80 Ma of metamorphism. Monazite compositional trends reflect the transition from prograde to retrograde metamorphism at 550 Ma. Eu anomalies in monazite reflect changes in fO_2 relative to quartzâfayaliteâmagnetite related to the growth and breakdown of spinel. The ratio Gd/Yb in monazite records the growth and breakdown of garnet. High rates of radiogenic heat production were the primary control on metamorphic grade at the regional scale. The short duration of prograde metamorphism in the osumilite gneisses (<29 ± 8 Ma) suggests that a thin mantle lithosphere (<80 km) or advective heating may have also been important in the formation of this highâT, lowâP terrane
Estimating Luminosity Function Constraints from High-Redshift Galaxy Surveys
The installation of the Wide Field Camera 3 (WFC3) on the Hubble Space
Telescope (HST) will revolutionize the study of high-redshift galaxy
populations. Initial observations of the HST Ultra Deep Field (UDF) have
yielded multiple z>~7 dropout candidates. Supplemented by the Great Observatory
Origins Deep Survey (GOODS) Early Release Science (ERS) and further UDF
pointings, these data will provide crucial information about the most distant
known galaxies. However, achieving tight constraints on the z~7 galaxy
luminosity function (LF) will require even more ambitious photometric surveys.
Using a Fisher matrix approach to fully account for Poisson and cosmic sample
variance, as well as covariances in the data, we estimate the uncertainties on
LF parameters achieved by surveys of a given area and depth. Applying this
method to WFC3 z~7 dropout galaxy samples, we forecast the LF parameter
uncertainties for a variety of model surveys. We demonstrate that performing a
wide area (~1 deg^2) survey to H_AB~27 depth or increasing the UDF depth to
H_AB~30 provides excellent constraints on the high-z LF when combined with the
existing UDF GO and GOODS ERS data. We also show that the shape of the matter
power spectrum may limit the possible gain of splitting wide area (>~0.5 deg^2)
high-redshift surveys into multiple fields to probe statistically independent
regions; the increased root-mean-squared density fluctuations in smaller
volumes mostly offset the improved variance gained from independent samples.Comment: Version accepted by ApJ
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Nanosecond Gating of Microstripline Microchannel Plate Framing Cameras: Characterization and Simulation
The soft x-ray microstripline microchannel plate (MCP) framing camera has become one of the workhorses of ICF diagnostics. Much progress has been made in making these diagnostics work well with gate times of 100 ps and below. Often weak input signal or source timing uncertainties dictate a requirement for longer gate times, preferably in the same instrument that also has fast gating capability. The large power-law dependence of MCP gain on applied voltage is useful in shortening the gating time of the microstripline camera. However, this sensitivity leads to tight constraints on the shape of the long duration electrical pulses that are needed to drive the MCP to produce experimentally desirable optical gating profiles. Simple modeling and measurements are used to better understand the character of the voltage pulses needed to achieve optical gate widths between 500 ps and {approx}2 ns
Design and implementation of high magnification framing camera for NIF "ARIANE Light"
Abstract not provide
Operational Research in Education
Operational Research (OR) techniques have been applied, from the early stages of the discipline, to a wide variety of issues in education. At the government level, these include questions of what resources should be allocated to education as a whole and how these should be divided amongst the individual sectors of education and the institutions within the sectors. Another pertinent issue concerns the efficient operation of institutions, how to measure it, and whether resource allocation can be used to incentivise efficiency savings. Local governments, as well as being concerned with issues of resource allocation, may also need to make decisions regarding, for example, the creation and location of new institutions or closure of existing ones, as well as the day-to-day logistics of getting pupils to schools. Issues of concern for managers within schools and colleges include allocating the budgets, scheduling lessons and the assignment of students to courses. This survey provides an overview of the diverse problems faced by government, managers and consumers of education, and the OR techniques which have typically been applied in an effort to improve operations and provide solutions
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