224 research outputs found
Pseudo-differential operators with isotropic symbols, Wick and anti-Wick operators, and hypoellipticity
No full textWe study the link between ilidos and Wick operators via the Bargmann transform. We deduce a formula for the symbol of the Wick operator in terms of the short-time Fourier transform of the Weyl symbol. This gives characterizations of Wick symbols of ilidos of Shubin type and of infinite order, and results on composition. We prove a series expansion of Wick operators in terms of anti-Wick operators which leads to a sharp Garding inequality and transition of hypoellipticity between Wick and Shubin symbols. Finally we show continuity results for anti-Wick operators, and estimates for the Wick symbols of anti-Wick operators.(c) 2022 The Author(s). Published by Elsevier Masson SAS. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/)
Structured approach to design of diagnostic test evaluation studies for chronic progressive infections in animals
No full textDiagnostic test evaluations (DTEs) for chronic infections are challenging because a protracted incubation period has to be considered in the design of the DTE, and the adverse effects of infection may be widespread and progressive over an animal's entire life. Frequently, the specific purpose of the test is not formally considered when a test is evaluated. Therefore, the result is often a DTE where test sensitivity and specificity estimates are biased, either because of problems with establishing the true infection status or because the test detects another aspect of the infection (and analyte) than originally intended. The objective of this paper is to outline a structured approach to the design and conduct of a DTE for diagnostic tests used for chronic infections in animals, and intended for different purposes. We describe the process from reflections about test purpose and the underlying target condition through considerations of the pathogenesis, and specification of a practical case definition, which can subsequently be used in the DTE for the specific purpose. The process is illustrated by two examples of Mycobacterium avium subsp. paratuberculosis (MAP) infections in cattle. MAP infections are chronic and can result in different adverse effects at different time points during the incubation period. The description provides input on the process and deductive reasoning which are integral parts to develop a high-quality design of a DTE for chronic infectious diseases.ID: S0378113511000381; M3: Article; Accession Number: S0378113511000381; Author: Søren Saxmose Nielsen (a, b, ⁎); Author: Nils Toft (a, b); Author: Ian Andrew Gardner (a, b); Affiliation: Department of Large Animal Sciences, Faculty of Life Sciences, University of Copenhagen, Grønnegårdsvej 8, DK-1870 Frederiksberg C, Denmark; Affiliation: Department of Medicine and Epidemiology, School of Veterinary Medicine, University of California, Davis, CA 95616, USA; Keyword: Chronic infectious diseases; Keyword: Design strategy; Keyword: Diagnostic test evaluation; Keyword: Paratuberculosis; Number of Pages: 11; Language: English
Opportunities in Advanced Space Transportation Systems
No full textFuture Programs
Session Chairman: Robert F. Freitag, Deputy Director, Advanced Programs, NASA Headquarters
Session Organizer: Paul D. Toft, Sciences, Technology and Applications Office, NASA, Kennedy Space Cente
Diagonal double Kodaira structures on finite groups
No full textWe introduce some special presentations on finite groups, that we call
"diagonal double Kodaira structures" and whose existence is equivalent to the
existence of some special Kodaira fibred surfaces, that we call "diagonal
double Kodaira fibrations". This allows us to rephrase in purely algebraic
terms some results about finite Heisenberg groups, previously obtained in the
recent work of the author with A. Causin, and makes possible to extend them to
the case of arbitrary extra-special -groups.Comment: To appear in the Proceedings of the 2019 ISAAC Congress (Aveiro,
Portugal
Overview of Future Programs -ESA
No full textFuture Programs
Session Chairman: Robert F. Freitag, Deputy Director, Advanced Programs, NASA Headquarters
Session Organizer: Paul D. Toft, Sciences, Technology and Applications Office, NASA, Kennedy Space Cente
Overview of Future Programs -USA
No full textFuture Programs
Session Chairman: Robert F. Freitag, Deputy Director, Advanced Programs, NASA Headquarters
Session Organizer: Paul D. Toft, Sciences, Technology and Applications Office, NASA, Kennedy Space Cente
A basic elementary extension of the Duchet–Meyniel theorem
No full textAbstractThe Conjecture of Hadwiger implies that the Hadwiger number h times the independence number α of a graph is at least the number of vertices n of the graph. In 1982 Duchet and Meyniel [P. Duchet, H. Meyniel, On Hadwiger’s number and the stability number, Ann. of Discrete Math. 13 (1982) 71–74] proved a weak version of the inequality, replacing the independence number α by 2α−1, that is, (2α−1)⋅h≥n. In 2005 Kawarabayashi, Plummer and the second author [K. Kawarabayashi, M. Plummer, B. Toft, Improvements of the theorem of Duchet and Meyniel on Hadwiger’s Conjecture, J. Combinatorial Theory B 95 (2005) 152–167] published an improvement of the theorem, replacing 2α−1 by 2α−3/2 when α is at least 3. Since then a further improvement by Kawarabayashi and Song has been obtained, replacing 2α−1 by 2α−2 when α is at least 3.In this paper a basic elementary extension of the Theorem of Duchet and Meyniel is presented. This may be of help to avoid dealing with basic cases when looking for more substantial improvements. The main unsolved problem (due to Seymour) is to improve, even just slightly, the theorem of Duchet and Meyniel in the case when the independence number α is equal to 2. The case α=2 of Hadwiger’s Conjecture was first pointed out by Mader as an interesting special case
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The Holbrook bequest for commemorative plaques: tradition, narrative and 'local patriotism' in Victorian Nottingham
No full textMaterial Witnesses: Deconstructing Networks of Credibility and Objectivity in Medical Narratives from Mary Toft to the Contraceptive Pill
No full textIn this dissertation, I argue that to better understand the tangled, embedded human and nonhuman subjects and how their testimonies function in western medical history, we need to first understand their erasure. By using relationality as a reading method, I break apart who and with whom individuals make medical decisions by considering what constitutes evidence. In the Mary Toft case, expert witnessing informs the ways in which a reader trusts what the narrator claims. The medicolegal conventions of courtroom testimony shape the ways in which medical men wrote their pamphlets. These men shore up their credibility through descriptions of nonhuman animals and of material actants. I found these descriptions to hold either equal or greater credibility than Toft herself, even though Toft herself lied and these descriptions are flawed. Thus, it is through narrative devices that the medical authors of these pamphlets redeem themselves. I also critically engaged objectivity throughout this project. The emphasis on maintaining objectivity and thus explanatory power seeps into the intimate spaces of medicine at home and of foodstuff in the nineteenth century, particularly milk. This seepage into the domestic space may appear to be an affront to Victorian values, since the home was the bastion of the family and privacy; however, increased regulation of foodstuff and of public hygiene by the late nineteenth century, coupled with medical science’s authority over what it means to be clean, meant that the middle classes soon undertook to clean their personal spaces—inside and outside the body. I continue to critically engage objectivity in the fourth chapter. My reading of twentieth century examples of patient package inserts that accompanied early forms of contraceptive pills questions a patient’s use of these texts. I find that these informational sheets can contribute to withholding, skewing, or misleading descriptions of the risk(s) of these medications. This medical information clog is thusly used as proof that medical experts are essential to interpreting medical knowledge for patients rather than as proof of needed clarity in the text. Additionally, I find that potential resolutions to the issue of obstructing knowledge flow have failed. Later editions of Our Bodies, Ourselves take on the narrative strategies that position the reader as helpless, the text as facilitative, and western medicine as the most authoritative, meaning the battle to unseat medical patriarchy’s hold over our bodies has been lost. In the fifth chapter of this dissertation, I redesign English 160: Introduction to Studies in Women’s Writing as “Women Medical Writers/Writing Women’s Medicine.” I develop a posthuman feminist pedagogy by building upon Karin Murris’s posthuman child to reimagine what characterizes an active student. This reimagining allows me to develop a course that introduces students both to the troubles and contradictions within our very own western medical culture and to the scholarly practice of critical intersectionality as a research strategy. The design of this course especially affects life writing pedagogies and the design of life writing courses as I use archival materials in the classroom. Teaching these skillsets to undergraduates differs from other solutions medical narrative scholars have suggested. By including nonliterary genres, like the ones I studied in this dissertation, in undergraduate literary study because this is where the interpretation of patient/illness happens. Author/practitioners interpret, assume, and preconceive descriptions based on these nonliterary genres, so it makes sense to study those very texts. Thus, if we are to truly think critically about moral issues in western medicine, then we must include the sites at which these moral issues are brought to fruition
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