Michael Brown - Profile on Academia.edu (original) (raw)

Papers by Michael Brown

Prediction of Elastic Properties Within CO 2 Plume at Sleipner Field Using AVS Inversion Modified for Thin‐Layer Reflections Guided by Uncertainty Estimation

Journal of Geophysical Research: Solid Earth, 2020

Existing amplitude variation with offset (AVO) and slowness (AVS) theories fail to interpret obse... more Existing amplitude variation with offset (AVO) and slowness (AVS) theories fail to interpret observed amplitudes in terms of actual elastic properties of the media for a reflection event resulting from a stack of thin layers. We propose a method to replace the stack of thin layers with an equivalent medium of elastic properties using the Backus averaging theory. Numerical examples show considerable deviation in intercept calculated from the modified AVO and AVS theories from the conventional methods. AVS theory is preferred as it can be applied irrespective of impedance contrast in both precritical and postcritical reflections, and no spherical divergence correction is required. P and S wave velocities, density, and thickness of thin layers are determined using the inversion scheme of very fast simulated annealing (VFSA). Uncertainty in prediction is evaluated using an approximate marginal posterior probability density function and a parameter correlation matrix. We demonstrate our methodology on synthetic and real seismic data from the Sleipner field, which is a good example of enhanced seismic amplitudes due to interference among reflections from thin layers. We select 11 common depth point (CDP) gathers for amplitude analysis of four identified reflectors along a line of 3‐D seismic data acquired in 2008. Predicted mean models of CO2‐saturated sand layers at all locations show that the thickness, density, and P and S wave velocities vary from 5–7 m, 1.8–2.0 g/cm3, and 1,460–1,490 and 630–650 m/s, respectively. Our analysis suggests that the model parameters are well constrained and independent except at a few locations.

Physical Modelling in Geotechnics

On the Nature of Lyman-α Emitters

AIP Conference Proceedings, 2003

More than half of the approximately 360 Lyman-alpha emitters found by the LALA survey show rest e... more More than half of the approximately 360 Lyman-alpha emitters found by the LALA survey show rest equivalent widths (EWs) larger than 200 Å, which is the maximum EW expected for normal stellar population. The high EWs can be reproduced by stellar populations with high proportions of young, massive stars, or by type 2 AGNs, which are supposed to be detectable

Comparison of Monte Carlo simulations with analytic collision model

We test a Monte Carlo simulation of particle collisions based on a model by Takizuka and Abe [JCP... more We test a Monte Carlo simulation of particle collisions based on a model by Takizuka and Abe [JCP 25, 205, (1977)]. This model is included in the Hamiltonian particle pushing code (PPC) for simulating particle orbits in the Swarthmore Spheromak eXperiment (SSX) MHD wind tunnel. The simulated dynamics, with collisions, are compared with analytical transport equations for slowing down, diffusion, and energy loss. Preliminary results show general agreement with the analytic model. The Takizuka collision model performs binary collisions between the test particle and a field particle drawn from a stationary Maxwellian background distribution of ions. The time difference between collisions is dependent on the current plasma parameters. Realistic particle dynamics in simulated SSX wind tunnel fields will be presented if available.

Process Safety and Environmental Protection, 2001

Revista Brasileira de Cirurgia Cardiovascular, 2009

Results of beating heart mitral valve surgery via the trans-septal approach Resultados da abordag... more Results of beating heart mitral valve surgery via the trans-septal approach Resultados da abordagem transeptal para a valva mitral com coração batendo Resumo Objetivo: A cirurgia da valva mitral pode ser feita via transatrial ou transeptal. Embora a transatrial seja a preferida, a via transeptal tem sido utilizada mais recentemente e tido um grande valor nas operações com o coração batendo. Mostramos a nossa experiência na cirurgia da valva mitral via transeptal com coração batendo e discutimos seus benefícios e problemas. Métodos: Entre 2000 e 2007, 214 pacientes consecutivos foram operados com o coração batendo. A operação foi feita por via transeptal sem pinçamento da aorta, com o coração batendo e eletrocardiograma normal e em ritmo sinusal. Resultados: A idade média foi de 56,03 ± 13,93 anos (intervalo: 19-86 anos; mediana: 56 anos). Havia 131 (61,2%) pacientes do sexo masculino e 83 (38,8%), do feminino. Foram utilizadas 108 (50,5%) próteses biológicas e 39 (18,2%) mecânicas. Reparo da valva foi feito em 67 (31,3%) pacientes. A estadia hospitalar foi de 17,4 ± 20,0 dias (intervalo: 3-135 dias; mediana: 11 dias). Balão intra-aórtico foi utilizado em 12 (5,6%) pacientes. A mortalidade hospitalar foi de 7,4%. Reoperação para revisão de hemostasia foi necessária em 15 pacientes. Conclusão: A operação com o coração batendo é uma opção para proteção miocárdica em pacientes submetidos a cirurgia da valva mitral. A técnica é facilitada ao se usar a via transeptal, reduzindo a insuficiência aórtica e melhorando a visualização do aparato mitral.

2012 IEEE International Conference on Green Computing and Communications, 2012

The Internet of Things (IoT) presents huge potential for designing new technologies. However it i... more The Internet of Things (IoT) presents huge potential for designing new technologies. However it is not yet clear which of these technologies will actually be accepted as a part of our everyday lives. Alongside the development of prototypes and exploratory evaluations, other research methods could be useful in eliciting responses to future visions, and developing implications that can inform design. In this paper we explore factors that could affect the acceptance of IoT technologies in the home. We present a review of relevant literature from human factors, HCI, sociology and psychology, and analyse the results of a survey in which participants were presented with scenarios of near-future IoT systems in use in the home. Based on this, we develop an initial set of design principles for IoT technologies in the home.

Lecture Notes in Computer Science, 2014

This paper discusses the practical implications of applying cultural probes to drive the design o... more This paper discusses the practical implications of applying cultural probes to drive the design of assistive technologies. Specifically we describe a study in which a probe was deployed with home-based carers of people with dementia in order to capture critical data and gain insights of integrating the technologies into this sensitive and socially complex design space. To represent and utilise the insights gained from the cultural probes, we created narratives based on the probe data to enhance the design of assistive technologies.

The Analyst, 2010

Infrared spectra of single biological cells often exhibit the 'dispersion artefact' observed as a... more Infrared spectra of single biological cells often exhibit the 'dispersion artefact' observed as a sharp decrease in intensity on the high wavenumber side of absorption bands, in particular the Amide I band at $1655 cm À1 , causing a downward shift of the true peak position. The presence of this effect makes any biochemical interpretation of the spectra unreliable. Recent theory has shed light on the origins of the 'dispersion artefact' which has been attributed to resonant Mie scattering (RMieS). In this paper a preliminary algorithm for correcting RMieS is presented and evaluated using simulated data. Results show that the 'dispersion artefact' appears to be removed; however, the correction is not perfect. An iterative approach was subsequently implemented whereby the reference spectrum is improved after each iteration, resulting in a more accurate correction. Consequently the corrected spectra become increasingly more representative of the pure absorbance spectra. Using this correction method reliable peak positions can be obtained.

Political Geography, 2005

My discussion of Engin Isin's monumental tome Being Political takes the form of a public letter t... more My discussion of Engin Isin's monumental tome Being Political takes the form of a public letter to him. Rather than reviewing the book, I draw on my background and concerns as an urban political geographer to ask him three questions. The first asks him to focus and explicate his idea of ''politics'' and ''the political''. The second asks him to consider the possibility for being political in rural places. The third asks him to expound on the chronological organization of the book, which seems ironically to reduce geography to 'the map of history'. My aim with this colloquy is to frame a productive, public conversation amongst political geographers and citizenship scholars.

Political Geography, 2006

While rights and freedoms of sexual citizenship have been foregrounded in geography, vaguer atten... more While rights and freedoms of sexual citizenship have been foregrounded in geography, vaguer attention has been given to questions of political obligation. Feminist work on political obligation, grounded with a framing in political ecology of disease, however, provides a means to correct this neglect. Empirically, I narrate a story of local public health politics in Seattle, WA. There, a cultural panic played out in the media over the alleged failure of political obligations by gay men around sexually transmitted infections. Political obligation and ecology usefully extend the concept sexual citizenship on its own terms by moving beyond a rights-versus-obligation polarity, highlighting the biophysical realities of sex, recognizing the spaces in which sex occurs, and noting the social relations inherent in sex and sexuality. Thus, this paper contributes to deeper thinking for activists involved in working through these questions as well as bolstering the notion of sexual citizenship in political geography.

Magnetic Resonance Imaging, 1991

Resonant forward scattering of sound in deep ocean environments

The Journal of the Acoustical Society of America, 2008

ABSTRACT The importance of resonantforward scattering of sound by highly directional large amplit... more ABSTRACT The importance of resonantforward scattering of sound by highly directional large amplitude nonlinear internal waves in shallow water environments has been well established. In contrast, most deep ocean environments are characterized by the presence of a sound speed perturbation (due mostly to internal waves) whose horizontal wave number spectrum is broad and approximately horizontally isotropic; under such conditions, the importance of resonantforward scattering is less clear. Exceptional deep ocean conditions are found in the vicinity of submarine ridges, which serve to generate internal tides that are both highly directional and have a narrow horizontal wave number spectrum. In this talk, ray, mode, and PE simulations are presented to explore the importance of resonantforward scattering by such structures under fairly realistic oceanographic conditions. [Work supported by ONR.]

Journal of Pharmaceutical Sciences, 1973

Formulations of retinoic acid for the topical treatment of ichthyosiform and seborrheic dermatose... more Formulations of retinoic acid for the topical treatment of ichthyosiform and seborrheic dermatoses were developed. They were evaluated for their skin irritation potential on rabbits, as a measure of pharmacological "activity," by studying erythema and scab-formation times. Different types of vehicles and varying concentrations of retinoic acid were studied. It was found that relatively high concentrations of retinoic acid (0. 1 4 2~) were necessary in lipophilic vehicles (in which retinoic acid is relatively insoluble) to achieve a desirable irritation level. Such formulations should be useful for treating ichthyosiform dermatoses. Conversely, it was found that relatively low concentrations of retinoic acid (O.OOl-O.OSO~) were preferable in hydrophilic vehicles (in which retinoic acid is relatively soluble) to achieve a desirable irritation level. Such formulations should be useful for treating seborrheic derrnatoses. Keyphrases 0 Retinoic acid-development of topical formulations for treatment of ichthyosiform and seborrheic dermatoses 0 Topical formulations, retinoic acid-developed for treatment of ichthyosiform and seborrheic dermatoses 0 Dermatology-retinoic acid formulations developed for treatment of ichthyosiform and seborrheic dermatoses 0 Ichthyosis, treatmentdevelopment of retinoic acid formulations 0 Seborrhea, treatment-development of retinoic acid formulations

Several new experimental results are reported from plasma merging studies at the Swarthmore Spher... more Several new experimental results are reported from plasma merging studies at the Swarthmore Spheromak Experiment (SSX) with relevance to three dimensional magnetic reconnection in laboratory and space plasmas. First, recent high-resolution velocity measurements of impurity ions using ion Doppler spectroscopy (IDS) show bi- directional outflow jets at 40 km/s (nearly the Alfv'en speed). Second, ion heating to nearly 10^6 K is observed after reconnection events in a low density regime. Third, the out-of-plane magnetic field in a reconnection volume shows a quadrupolar structure at the ion inertial scale (c/phipi). Time resolved vector magnetic field measurements on a 3D lattice (B(r, t)) enables this measurement. Each of these measurements will be related to and compared with similar observations in a solar or space context.

Editorial change

Journal of Metamorphic Geology, 1985

“Earnest Spade Work”: The New Zealand Folklore Society, 1966–1975

Journal of Folklore Research: An International Journal of Folklore and Ethnomusicology, 2007

Page 1. "Earnest Spade Work": The New Zealand Folklore Society, 1966-1975 Micha... more Page 1. "Earnest Spade Work": The New Zealand Folklore Society, 1966-1975 Michael Brown Abstract: The New Zealand Folklore Society was a small organisation that emerged from the folk revival scene in Wellington, New Zealand, in 1966. ...

Human Immunology, 2011

To study the various human leukocyte antigen (HLA) allele and loci mismatching in the high resolu... more To study the various human leukocyte antigen (HLA) allele and loci mismatching in the high resolution level impact to success of unrelated donor HSCT. Methods: China Marrow Donor Program data from 835 transplantations performed from 2005 to 2010 were analyzed. 835 patient-donor pairs were fully typed for HLA-A,-B,-C,-DRB1 and DQB1 alleles using SBT, SSOP and SSP methods. All the patients were undergoing transplantation for AML (nϭ288), ALL (nϭ227), CML (nϭ187), MDS(nϭ52), NHL(nϭ25), AA(nϭ42) and mediterranean anemia(nϭ14). Results: The overall survival (OS) rates of HLA fully matched (10/10) pairs was 79.83%. The HLA mismatched pairs was lower OS rates (73.15%) compared with the HLA matched pairs, but there were no statistically significant differences(pϭ0.094). In the HLA mismatched pairs, the OS rates of recipient/donor for single HLA allele mismatch was 74.21%,single HLA-C, or DQB1 antigen mismatches was 76.0%, double HLA allele mismatches was 79.31%, both single allele and single antigen HLA mismatches was 68.42%, double HLA antigen mismatches was 75.0%, multiple allele and antigen mismatches was 66.67%. The donorrecipient with both single allele and single antigen HLA mismatches were statistically significant differences associated with lower survival compared with fully matched pairs(pϭ0.007) using Kaplan-Meier. The OS of CML patients had statistically difference compared with ALL patients (pϭ0.037). Mismatching of HLA-A,-B,-C,-DRB1 or DQB1locus was associated with more acute GVHD compared with HLA-matched pairs. There were statistically significant differences in higher risk associated withII-IVaGVHD(pϭ0.000)estimator. Conclusions: The recipient-donor with both mismatches of single allene and antigen at HLA-A,-B,-C,-DRB1 or DQB1 appear lower overall survival than mismatches of single allene or single antigen after HSCT. So the high-resolution DNA typing for HLA-A,-B,-C,-DRB1 and DQB1 alleles can be improved higher rates of survival on unrelated donor HSCT.

Geology, 1998

The common spatial relationship in convergent orogenic belts between a crustal-scale shearzone sy... more The common spatial relationship in convergent orogenic belts between a crustal-scale shearzone system, high-grade metamorphic rocks, and granites suggests a feedback relation between crustal anatexis and contractional deformation that helps granite extraction and focuses granite ascent. Such a feedback relation has been proposed for ascent of Early Devonian granites in westcentral Maine. This interpretation requires that deformation, metamorphism, and plutonism were synchronous. We have determined precise U-Pb zircon and monazite ages that we interpret to record time of crystallization of syntectonic granite in metric to decametric sheets and kilometric plutons, and of schlieric granite within migmatites. Ages are in the range ca. 408-404 Ma, within 1 m.y. at 95% confidence limits. These ages are similar to extant U-Pb monazite ages of ca. 405-399 ± 2 Ma for syntectonic regional metamorphism in the same area. The coincidence between the age of peak metamorphism and crystallization ages of granite shows tectonics, metamorphism, and magmatism were contemporaneous, in support of the feedback model.

Queer diffusions

Environment and Planning D: Society and Space, 2003

Critical perspectives on space and spatiality have been underdeveloped theoretically and underapp... more Critical perspectives on space and spatiality have been underdeveloped theoretically and underapplied empirically in the context of queer studies (including queer theory). In this paper we demonstrate how critical perspectives on one form of spatiality, diffusion, can enhance understandings of queer cultures, identities, and politics. We begin by reviewing traditional approaches to diffusion within geography and explicating a specifically queer approach to the topic. Our approach builds on existing critical perspectives and certain principles of structurationism. We then apply this approach to our empirical research and activism in two very different locales: Duluth, Minnesota, and Seattle, Washington. In so doing we illustrate the complex and nuanced spatialities of heteronormative power and resistances to it.