284 research outputs found
A reinforcement learning model for AI-based decision support in skin cancer
No full text: We investigated whether human preferences hold the potential to improve diagnostic artificial intelligence (AI)-based decision support using skin cancer diagnosis as a use case. We utilized nonuniform rewards and penalties based on expert-generated tables, balancing the benefits and harms of various diagnostic errors, which were applied using reinforcement learning. Compared with supervised learning, the reinforcement learning model improved the sensitivity for melanoma from 61.4% to 79.5% (95% confidence interval (CI): 73.5-85.6%) and for basal cell carcinoma from 79.4% to 87.1% (95% CI: 80.3-93.9%). AI overconfidence was also reduced while simultaneously maintaining accuracy. Reinforcement learning increased the rate of correct diagnoses made by dermatologists by 12.0% (95% CI: 8.8-15.1%) and improved the rate of optimal management decisions from 57.4% to 65.3% (95% CI: 61.7-68.9%). We further demonstrated that the reward-adjusted reinforcement learning model and a threshold-based model outperformed naïve supervised learning in various clinical scenarios. Our findings suggest the potential for incorporating human preferences into image-based diagnostic algorithms
Retelling racialized violence, remaking white innocence: the politics of interlocking oppressions in transgender day of remembrance
No full textTransgender Day of Remembrance has become a significant political event among those resisting violence against gender-variant persons. Commemorated in more than 250 locations worldwide, this day honors individuals who were killed due to anti-transgender hatred or prejudice. However, by focusing on transphobia as the definitive cause of violence, this ritual potentially obscures the ways in which hierarchies of race, class, and sexuality constitute such acts. Taking the Transgender Day of Remembrance/Remembering Our Dead project as a case study for considering the politics of memorialization, as well as tracing the narrative history of the Fred F. C. Martinez murder case in Colorado, the author argues that deracialized accounts of violence produce seemingly innocent White witnesses who can consume these spectacles of domination without confronting their own complicity in such acts. The author suggests that remembrance practices require critical rethinking if we are to confront violence in more effective ways. Description from publisher's site: http://caliber.ucpress.net/doi/abs/10.1525/srsp.2008.5.1.2
Theology in suspense : how the detective fiction of P.D. James provokes theological thought
No full textElectronic redacted version excludes material for which permission has not been granted by the rights holderThe following dissertation argues that the detective fiction of P.D. James
provokes her readers to think theologically. I present evidence from the body of
James’s work, including her detective fiction that features the Detective Adam
Dalgliesh, as well as her other novels, autobiography, and non-fiction work. I also
present a brief history of detective fiction. This history provides the reader with a
better understanding of how P.D James is influenced by the detective genre as well as
how she stands apart from the genre’s traditions.
This dissertation relies on an interview that I conducted with P.D. James in
November, 2008. During the interview, I asked James how Christianity has
influenced her detective fiction and her responses greatly contribute to this
dissertation. However, James’s novels should be interpreted and explored in the
manner that they are received by the reader. How the reader receives and responds to
the novels, not only how James writes the novels, is what causes her stories to
provoke theological thinking.
By examining Christian symbolism that is present in setting, character, the
Detective Adam Dalgliesh, and plot, this dissertation seeks to assert that James
contributes to a theological conversation through her popular detective fiction
A comparative evaluation of interactive segmentation algorithms
No full textIn this paper we present a comparative evaluation of four popular interactive segmentation algorithms. The evaluation was carried out as a series of user-experiments, in which participants were tasked with extracting 100 objects from a common dataset: 25 with each algorithm, constrained within a time limit of 2 min for each object. To facilitate the experiments, a “scribble-driven” segmentation tool was developed to enable interactive image segmentation by simply marking areas of foreground and background with the mouse. As the participants refined and improved their respective segmentations, the corresponding updated segmentation mask was stored along with the elapsed time. We then collected and evaluated each recorded mask against a manually segmented ground truth, thus allowing us to gauge segmentation accuracy over time. Two benchmarks were used for the evaluation: the well-known Jaccard index for measuring object accuracy, and a new fuzzy metric, proposed in this paper, designed for measuring boundary accuracy. Analysis of the experimental results demonstrates the effectiveness of the suggested measures and provides valuable insights into the performance and characteristics of the evaluated algorithms
(The) man, his body, and his society: masculinity and the male experience in English and Scottish medicine c.1640-c.1780.
No full textThis thesis examines the relationship(s) between medicine, the body and societal codes of masculinity in England and Scotland between c.1640 and c.1780. It responds to the way in which the men in histories of post-1660 masculinity are often disembodied, and to the comparative absence of men’s gendered experiences from the history of medicine. Its findings show that in both centuries the experience of being a man with a body that was the site of health and sickness was an open, candid, and often communal, one, inside and outside of the formal medical encounter. Thus, and on both sides of 1700, ill men had full freedom in the pursuit and acceptance of medical, familial and social assistance, while their physical suffering, and associated emotional distress, was met with sympathy. With their sick bodies the sites of honest self-examination and open discussion, it was in part this very public nature of their sicknesses that allowed men, as a gender and as individuals, independence and agency in their non-commercial health care. Indeed, later-seventeenth- and eighteenth-century men suffered no constraints in their ability to respond to the vulnerabilities of their bodies, even where this involved behaviours or attributes allegedly associated with women and femininity, or inconsistent with ideals of active, independent, masculinity.
These findings indicate, therefore, great continuity across the period 1640-1780, and not only in masculine ideals of and involving the male corporeality. There seems to have been significant consistency across time in men’s social and medical experiences of both sickness and their pre-emptive preparation for it, and in an apparent collective self-confidence concerning their corporeal masculinity, their sex, and, possibly, even their sexual potential. Indeed, these sources suggest that seventeenth- and eighteenth-century men had a resilient sense of self-identity (and personal masculinity), conceptually separable from the corporeal body and its known fragilities
The problem of blasphemy: The fourth gospel and early Jewish understandings
No full textThis thesis argues that the Johannine Jewish Christians—those who produced, preserved, and propagated the Fourth Gospel—were perceived to be blasphemers of God because of their exalted claims for Jesus and their disparaging remarks against the Ιουδαιοι. It was probably on this basis that Jewish Christians were excommunicated from the synagogue (cf Jn 9:22; 12:42; 16:2). We take three steps to establish this claim. First, we review J. Louis Martyn's hypothesis that the Johannine Christians were expelled from the synagogue as a result of the Birkat ha-Minim. We argue that the Birkat ha-Minim is problematic, suggest that an alternative hypothesis is necessary, and propose that accusations of blasphemy would provide an alternative explanation. Next, we survey recent research on blasphemy, offer an analysis of the historical, social, and literary context of the Fourth Gospel, and present a semantic analysis of βλασφημέωand related terms. Second, we probe seven Jewish traditions pertaining to blasphemy. We examine the prohibitions against cursing God (Exod 22:27[28]), "naming the name" (Lev 24:10- 24), and sinning with a high hand (Num 15:30-31). Then, we track some of the most notorious blasphemers, including Sennacherib (2 Kgs 18:1—19:37), Antiochus (1 Mace 1:20—2:14), Nicanor (2 Mace 14:16—15:37), and an unnamed Egyptian ruler 2.123-132).Third, we examine three Johannine claims—that Jesus is equal with God, that Jesus is the New Temple, and that the ' Ιουδαιοι are of the devil -and argue that non-believing Jews would have regarded these claims as blasphemous and would have expelled anyone from the synagogue who proclaimed them
Machine learning derived segmentation of phase velocity encoded cardiovascular magnetic resonance for fully automated aortic flow quantification
No full textAbstract Background Phase contrast (PC) cardiovascular magnetic resonance (CMR) is widely employed for flow quantification, but analysis typically requires time consuming manual segmentation which can require human correction. Advances in machine learning have markedly improved automated processing, but have yet to be applied to PC-CMR. This study tested a novel machine learning model for fully automated analysis of PC-CMR aortic flow. Methods A machine learning model was designed to track aortic valve borders based on neural network approaches. The model was trained in a derivation cohort encompassing 150 patients who underwent clinical PC-CMR then compared to manual and commercially-available automated segmentation in a prospective validation cohort. Further validation testing was performed in an external cohort acquired from a different site/CMR vendor. Results Among 190 coronary artery disease patients prospectively undergoing CMR on commercial scanners (84% 1.5T, 16% 3T), machine learning segmentation was uniformly successful, requiring no human intervention: Segmentation time was < 0.01 min/case (1.2 min for entire dataset); manual segmentation required 3.96 ± 0.36 min/case (12.5 h for entire dataset). Correlations between machine learning and manual segmentation-derived flow approached unity (r = 0.99, p < 0.001). Machine learning yielded smaller absolute differences with manual segmentation than did commercial automation (1.85 ± 1.80 vs. 3.33 ± 3.18 mL, p < 0.01): Nearly all (98%) of cases differed by ≤5 mL between machine learning and manual methods. Among patients without advanced mitral regurgitation, machine learning correlated well (r = 0.63, p < 0.001) and yielded small differences with cine-CMR stroke volume (∆ 1.3 ± 17.7 mL, p = 0.36). Among advanced mitral regurgitation patients, machine learning yielded lower stroke volume than did volumetric cine-CMR (∆ 12.6 ± 20.9 mL, p = 0.005), further supporting validity of this method. Among the external validation cohort (n = 80) acquired using a different CMR vendor, the algorithm yielded equivalently small differences (∆ 1.39 ± 1.77 mL, p = 0.4) and high correlations (r = 0.99, p < 0.001) with manual segmentation, including similar results in 20 patients with bicuspid or stenotic aortic valve pathology (∆ 1.71 ± 2.25 mL, p = 0.25). Conclusion Fully automated machine learning PC-CMR segmentation performs robustly for aortic flow quantification - yielding rapid segmentation, small differences with manual segmentation, and identification of differential forward/left ventricular volumetric stroke volume in context of concomitant mitral regurgitation. Findings support use of machine learning for analysis of large scale CMR datasets
Motzkin decomposition of closed convex sets via truncation
No full textA nonempty set F is called Motzkin decomposable when it can be expressed as the Minkowski sum of a compact convex set C with a closed convex cone D. In that case, the sets C and D are called compact and conic components of F. This paper provides new characterizations of the Motzkin decomposable sets involving truncations of F (i.e., intersections of FF with closed halfspaces), when F contains no lines, and truncations of the intersection F̂ of F with the orthogonal complement of the lineality of F, otherwise. In particular, it is shown that a nonempty closed convex set F is Motzkin decomposable if and only if there exists a hyperplane H parallel to the lineality of F such that one of the truncations of F̂ induced by H is compact whereas the other one is a union of closed halflines emanating from H. Thus, any Motzkin decomposable set F can be expressed as F=C+D, where the compact component C is a truncation of F̂. These Motzkin decompositions are said to be of type T when F contains no lines, i.e., when C is a truncation of F. The minimality of this type of decompositions is also discussed.This work has been supported by the MICINN of Spain, Grants MTM2011-29064-C03-01&02, by the Barcelona Graduate School of Economics, by the Government of Catalonia, by CONACyT of Mexico, Grant 55681, and by CNPq of Brazil, Grant 301280/86. The first author is Partner Investigator in the Australian Research Council Discovery Project DP120100467. The third author is affiliated toMOVE(Markets, Organizations and Votes in Economics)
The sweat of the brain: representations of intellectual labour in the writings of Edmund Burke, William Cobbett, William Hazlitt and Thomas Carlyle
No full textThis thesis examines representations of intellectual work in the writings of Edmund Burke, William Cobbett, William Hazlitt, and Thomas Carlyle, focusing on their tendency to draw on an analogy between mental and manual labour when representing their own work to themselves and to their readers. It is my argument that while the assimilation of intellectual to physical labour can be seen as a symptom of political bad faith - suggesting, as it does, that thinking and writing are as painful or as difficult as digging and ploughing - the primary purposes of the analogy in the works of these four cultural commentators are, first, to forge rhetorical alliances with ordinary labourers, and, second, to attack other intellectuals engaged in what are alleged to be less arduous and less valuable forms of intellectual endeavour. By blaming the irresponsible activity of disaffected literary men for the political upheaval of the French Revolution, Burke set the terms for debate about the role of educated and literate men in society, a debate in which, for the first time, intellectuals competed for the allegiance of the labouring population. The analogy with manual labour was a key rhetorical site in the struggle to define an ideology for intellectuals, since it claims to ground the speaker or writer in the labouring community at large. For each author, I undertake close readings of several key texts to demonstrate the prevalence of the comparison with manual labour in the representation of intellectual activity. The political-ideological valence of the analogy is never straightforward, I contend, and it often occurs alongside an impulse to emphasise, as well as to elide, what are assumed to be the fundamental differences between mental and manual activity. We witness in the writings of Burke, Cobbett, Hazlitt, and Carlyle a recognisable mode of self-representation, for the desire to assimilate intellectual to material work has persisted
Robert Buchanan 1841-1901: an assessment of his career.
No full textPhDRobert Buchanan was widely regarded during his
lifetime as a poet of distinction, a capable and powerful
novelist, and a critic of some perception, yet his name is
now associated only with one regrettable episode, while
those of lesser men and women continue to be remembered for
work inferior to his. A man possessing large reserves of
energy, and pressed to write for a living at an early age,
he produced much work that deserves the oblivion it has
found; but his early verse, expressing his profound compassion
for the sufferings of the unfortunate in the simplest
language, some of his ballads, and not a little of his
later more vatic verse, is still worthy of study. As a
novelist his work is provocative and readable, but too
often descends to the level of the sentimental melodrama
which earned him, for a while, a very good income from the
stage. As a critic he was not profound, but was quick to
detect and praise expression of his own sympathy for humanity
that came to represent for him art's highest aspiration;
Dickens, Browning and Whitman were his heroes, and for the
last two he did sterling work in helping them to gain widespread
recognition. As a polemist he rushed into several
arenas, for some of which his talents were not especially
suited; but he publicly supported C. S. Parnell and Oscar
Wilde when few found the courage to do so. An interesting
man of impressive variety and undoubted talent has found an
undeserved neglect, and a full-scale critical biography of
Robert Buchanan is long overdue
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