78 research outputs found
Representational ethical model calibration
Equity is widely held to be fundamental to the ethics of healthcare. In the context of clinical decision-making, it rests on the comparative fidelity of the intelligence – evidence-based or intuitive – guiding the management of each individual patient. Though brought to recent attention by the individuating power of contemporary machine learning, such epistemic equity arises in the context of any decision guidance, whether traditional or innovative. Yet no general framework for its quantification, let alone assurance, currently exists. Here we formulate epistemic equity in terms of model fidelity evaluated over learnt multidimensional representations of identity crafted to maximise the captured diversity of the population, introducing a comprehensive framework for Representational Ethical Model Calibration. We demonstrate the use of the framework on large-scale multimodal data from UK Biobank to derive diverse representations of the population, quantify model performance, and institute responsive remediation. We offer our approach as a principled solution to quantifying and assuring epistemic equity in healthcare, with applications across the research, clinical, and regulatory domains
Interband mixing between two-dimensional states localized in a surface quantum well and heavy hole states of the valence band in narrow gap semiconductor
Theoretical calculations in the framework of Kane model have been carried out
in order to elucidate the role of interband mixing in forming the energy
spectrum of two-dimensional carriers, localized in a surface quantum well in
narrow gap semiconductor. Of interest was the mixing between the 2D states and
heavy hole states in the volume of semiconductor. It has been shown that the
interband mixing results in two effects: the broadening of 2D energy levels and
their shift, which are mostly pronounced for semiconductors with high doping
level. The interband mixing has been found to influence mostly the effective
mass of 2D carriers for large their concentration, whereas it slightly changes
the subband distribution in a wide concentration range.Comment: 12 pages (RevTEX) and 4 PostScript-figure
Tunnelling Studies of Two-Dimensional States in Semiconductors with Inverted Band Structure: Spin-orbit Splitting, Resonant Broadening
The results of tunnelling studies of the energy spectrum of two-dimensional
(2D) states in a surface quantum well in a semiconductor with inverted band
structure are presented. The energy dependence of quasimomentum of the 2D
states over a wide energy range is obtained from the analysis of tunnelling
conductivity oscillations in a quantizing magnetic field. The spin-orbit
splitting of the energy spectrum of 2D states, due to inversion asymmetry of
the surface quantum well, and the broadening of 2D states at the energies, when
they are in resonance with the heavy hole valence band, are investigated in
structures with different strength of the surface quantum well. A quantitative
analysis is carried out within the framework of the Kane model of the energy
spectrum. The theoretical results are in good agreement with the tunnelling
spectroscopy data.Comment: 29 pages, RevTeX, submitted in Phys.Rev.B. Figures available on
request from [email protected]
Is It Rational to Assume that Infants Imitate Rationally? A Theoretical Analysis and Critique
It has been suggested that preverbal infants evaluate the efficiency of others' actions (by applying a principle of rational action) and that they imitate others' actions rationally. The present contribution presents a conceptual analysis of the claim that preverbal infants imitate rationally. It shows that this ability rests on at least three assumptions: that infants are able to perceive others' action capabilities, that infants reason about and conceptually represent their own bodies, and that infants are able to think counterfactually. It is argued that none of these three abilities is in place during infancy. Furthermore, it is shown that the idea of a principle of rational action suffers from two fallacies. As a consequence, is it suggested that it is not rational to assume that infants imitate rationally. Copyright (C) 2012 S. Karger AG, Base
Neural correlates of evidence accumulation during value-based decisions revealed via simultaneous EEG-fMRI
Current computational accounts posit that, in simple binary choices, humans accumulate
evidence in favour of the different alternatives before committing to a decision. Neural
correlates of this accumulating activity have been found during perceptual decisions in
parietal and prefrontal cortex; however the source of such activity in value-based choices
remains unknown. Here we use simultaneous EEG–fMRI and computational modelling to
identify EEG signals reflecting an accumulation process and demonstrate that the within- and
across-trial variability in these signals explains fMRI responses in posterior-medial frontal
cortex. Consistent with its role in integrating the evidence prior to reaching a decision, this
region also exhibits task-dependent coupling with the ventromedial prefrontal cortex and
the striatum, brain areas known to encode the subjective value of the decision alternatives.
These results further endorse the proposition of an evidence accumulation process
during value-based decisions in humans and implicate the posterior-medial frontal cortex in
this process
Genetic and neurological foundations of customer orientation: field and experimental evidence
We explore genetic and neurological bases for customer orientation (CO) and contrast them with sales orientation (SO). Study 1 is a field study that establishes that CO, but not SO, leads to greater opportunity recognition. Study 2 examines genetic bases for CO and finds that salespeople with CO are more likely to have the 7R variant of the DRD4 gene. This is consistent with basic research on dopamine receptor activity in the brain that underlies novelty seeking, the reward function, and risk taking. Study 3 examines the neural basis of CO and finds that salespeople with CO, but not SO, experience greater activation of their mirror neuron systems and neural processes associated with empathy. Managerial and research implications are discussed
Applauding with Closed Hands: Neural Signature of Action-Sentence Compatibility Effects
BACKGROUND: Behavioral studies have provided evidence for an action-sentence compatibility effect (ACE) that suggests a coupling of motor mechanisms and action-sentence comprehension. When both processes are concurrent, the action sentence primes the actual movement, and simultaneously, the action affects comprehension. The aim of the present study was to investigate brain markers of bidirectional impact of language comprehension and motor processes. METHODOLOGY/PRINCIPAL FINDINGS: Participants listened to sentences describing an action that involved an open hand, a closed hand, or no manual action. Each participant was asked to press a button to indicate his/her understanding of the sentence. Each participant was assigned a hand-shape, either closed or open, which had to be used to activate the button. There were two groups (depending on the assigned hand-shape) and three categories (compatible, incompatible and neutral) defined according to the compatibility between the response and the sentence. ACEs were found in both groups. Brain markers of semantic processing exhibited an N400-like component around the Cz electrode position. This component distinguishes between compatible and incompatible, with a greater negative deflection for incompatible. Motor response elicited a motor potential (MP) and a re-afferent potential (RAP), which are both enhanced in the compatible condition. CONCLUSIONS/SIGNIFICANCE: The present findings provide the first ACE cortical measurements of semantic processing and the motor response. N400-like effects suggest that incompatibility with motor processes interferes in sentence comprehension in a semantic fashion. Modulation of motor potentials (MP and RAP) revealed a multimodal semantic facilitation of the motor response. Both results provide neural evidence of an action-sentence bidirectional relationship. Our results suggest that ACE is not an epiphenomenal post-sentence comprehension process. In contrast, motor-language integration occurring during the verb onset supports a genuine and ongoing brain motor-language interaction
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