1,776 research outputs found
Mean-Variance and Expected Utility: The Borch Paradox
The model of rational decision-making in most of economics and statistics is
expected utility theory (EU) axiomatised by von Neumann and Morgenstern, Savage
and others. This is less the case, however, in financial economics and
mathematical finance, where investment decisions are commonly based on the
methods of mean-variance (MV) introduced in the 1950s by Markowitz. Under the
MV framework, each available investment opportunity ("asset") or portfolio is
represented in just two dimensions by the ex ante mean and standard deviation
of the financial return anticipated from that investment.
Utility adherents consider that in general MV methods are logically incoherent.
Most famously, Norwegian insurance theorist Borch presented a proof suggesting
that two-dimensional MV indifference curves cannot represent the preferences of
a rational investor (he claimed that MV indifference curves "do not exist").
This is known as Borch's paradox and gave rise to an important but generally
little-known philosophical literature relating MV to EU. We examine the main
early contributions to this literature, focussing on Borch's logic and the
arguments by which it has been set aside.Comment: Published in at http://dx.doi.org/10.1214/12-STS408 the Statistical
Science (http://www.imstat.org/sts/) by the Institute of Mathematical
Statistics (http://www.imstat.org
The search for modernity
Review of book: "From symbolic temple to dematerialization: a journey through library architecture from the 20th to the 21st century", by Daniel Gil-Solé
The search for modernity
Review of book: "From symbolic temple to dematerialization: a journey through library architecture from the 20th to the 21st century", by Daniel Gil-Solé
Elements of Social Learning Supporting Transformative Change
The body of literature on social learning is enormous, with differently framed ontologies and epistemologies aligned to multiple perspectives of learning in a social context. These have grown out of the many academic disciplines which have seen the value of social learning. This paper highlights the need to be aware of these multiple perspectives, and draws on the work of Lotz-Sisitka, Mukute and Belay (2012) to argue that there is a need to understand, and engage deeply with, the antecedent perspectives on social learning and to avoid ontological collapse in social-learning research in environmental education research and practice. It provides a broad-based understanding of transformative social learning by simply defining social learning with a socially critical orientation, and distilling key elements of social learning important to supporting social change. A recommendation is made for interventionist researchers and practitioners to use a theoretically sound, ontologically congruent methodology to support their social-learning research and implementation
El peso de la luz
The study explored whether the knowledge of Archimedes' law of the lever can be used to measure subjective intensities. Participants were presented with two achromatic rectangles on a horizontal line-drawn lever, one on the left and one on the right of the fulcrum. The left rectangle had a fixed low luminance. For different combinations of luminance and distance from the fulcrum of the right rectangle, participants were asked to position the left rectangle at a distance from the fulcrum such that the weight of the light emitted by the left rectangle kept the lever horizontal given the weight of the light emitted by the right rectangle. Most of the participants solved the task in accordance with their knowledge of Archimedes' law. This finding is interpreted to imply that the perceived distance of the left rectangle from the fulcrum was proportional to the perceived brightness of the right rectangle. It suggests that people's explicit or implicit knowledge of ratios and proportions in Archimedes' law of the lever, and perhaps in other physical laws, could potentially be used to measure any subjective intensity on a ratio scale
Interaction design and emotional wellbeing
The World Health Organisation has concluded that
emotional wellbeing is fundamental to our quality of
life. It enables us to experience life as meaningful and
is an essential component of social cohesion, peace and
stability in the living environment [21]. This workshop
will bring together a diverse community to consolidate
existing knowledge and identify new opportunities for
research on technologies designed to support emotional
wellbeing. The workshop will examine uses of
technology in mental health settings, but will also
consider the importance of emotional needs in physical
healthcare and wellbeing more generally. The design of
technology to provide social support and to extend
traditional care networks will be key workshop themes
Beerbohm Tree's 1904 version of Shakespeare's Tempest
An edition of Beerbohm Tree's acting text of Shakespeare's Tempest as printed in the souvenir programme for the 50th presentation of the production in 1904. Illustrations by Buchel from the programme together with other newspaper cartoons of the actors are included
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