577 research outputs found
Neurobiology of social and individual choice
In the course of our everyday lives, we are constantly faced with situations in which we must choose. Do we invest in the bank or the stock-market? Is a new wage deal so unfair that we should resort to a strike? These situations are elegantly described mathematically by Rational Choice Theory (RCT), which dominates the quantitative social sciences such as economics. However, unfortunately RCT often fails to predict how humans actually behave. Here I investigate choice using paradigms derived from the RCT framework, but aim to better predict actual choices by using a biological level of explanation. First, I examine simple choices that involve no social interaction, asking how choices are influenced by risk in potential outcomes, and by whether outcomes reflect potential gains or losses. The data reveal independent impacts of risk and loss on choice, findings not predicted by extant economic theories. Instead, I then harness functional Magnetic Resonance Imaging (fMRI) to suggest a biological mechanism by which risk and loss bias approach behaviour, and test this hypotheses in further behavioural experiments. Secondly, I examine social choices. Specifically, I examine biological systems that enable social behaviour to respond flexibly to environmental contingencies. I investigate the neural basis of the human fairness motivation using fMRI, and show how it flexibly adapts to external social context. Next, I show how this fairness motivation adapts to changes in an individualâs internal physiological state. Finally, I show how cooperation is modulated by the androgen hormone testosterone. Overall, in light of these non-social and social findings, I propose that a biologically-based account of choice can explain choices that are not predicted by existing theory
Dual task performance in older adults: examining visual discrimination whilst treadmill walking at preferred and non-preferred speeds
A conservative control strategy for variable-speed stall-regulated wind turbines
Simulation models of a variable-speed, fixed-pitch wind turbine were investigated to evaluate the feasibility of constraining rotor speed and power output without the benefit of active aerodynamic control devices. A strategy was postulated to control rotational speed by specifying the demanded generator torque. By controlling rotor speed in relation to wind speed, the aerodynamic power extracted by the blades from the wind was manipulated. Specifically, the blades were caused to stall in high winds. In low and moderate winds, the demanded generator torque and the resulting rotor speed were controlled to cause the wind turbine to operate near maximum efficiency. Using the developed models, simulations were conducted of operation in turbulent winds. Results indicated that rotor speed and power output were well regulated. Preliminary investigations of system dynamics showed that, compared to fixed-speed operation, variable-speed operation caused cyclic loading amplitude to be reduced for the turbine blades and low-speed shaft and slightly increased for the tower loads. This result suggests a favorable impact on fatigue life from implementation of the proposed control strategy
Pentagrams and paradoxes
Klyachko and coworkers consider an orthogonality graph in the form of a
pentagram, and in this way derive a Kochen-Specker inequality for spin 1
systems. In some low-dimensional situations Hilbert spaces are naturally
organised, by a magical choice of basis, into SO(N) orbits. Combining these
ideas some very elegant results emerge. We give a careful discussion of the
pentagram operator, and then show how the pentagram underlies a number of other
quantum "paradoxes", such as that of Hardy.Comment: 14 pages, 4 figure
Shape Analysis in the Absence of Pointers and Structure
discover properties of dynamic and/or mutable structures. We ask, âIs there an equivalent to shape analysis for purely functional programs, and if so, what âshapes â does it discover? â By treating binding environments as dynamically allocated structures, by treating bindings as addresses, and by treating value environments as heaps, we argue that we can analyze the âshape â of higher-order functions. To demonstrate this, we enrich an abstract-interpretive control-flow analysis with principles from shape analysis. In particular, we promote âanodization â as a way to generalize both singleton abstraction and the notion of focusing, and we promote âbinding invariants â as the analog of shape predicates. Our analysis enables two optimizations known to be beyond the reach of control-flow analysis (globalization and super-ÎČ inlining) and one previously unknown optimization (higher-order rematerialization).
Can induced gravity isotropize Bianchi I, V, or IX Universes?
We analyze if Bianchi I, V, and IX models in the Induced Gravity (IG) theory
can evolve to a Friedmann--Roberson--Walker (FRW) expansion due to the
non--minimal coupling of gravity and the scalar field. The analytical results
that we found for the Brans-Dicke (BD) theory are now applied to the IG theory
which has ( being the square ratio of the Higgs to
Planck mass) in a cosmological era in which the IG--potential is not
significant. We find that the isotropization mechanism crucially depends on the
value of . Its smallness also permits inflationary solutions. For the
Bianch V model inflation due to the Higgs potential takes place afterwads, and
subsequently the spontaneous symmetry breaking (SSB) ends with an effective FRW
evolution. The ordinary tests of successful cosmology are well satisfied.Comment: 24 pages, 5 figures, to be published in Phys. Rev. D1
Arctic shipping and polar seaways
Climate change in the Arctic triggered a series of discourses about the opening-up of a previously unreachable region. Navigation remains however difficult in the Arctic, transits are still very limited, as sea-ice still is a major constraint. How did the development policies of both the North West Passage and the Northern Sea Route unfold ? What are the recent trends in Arctic shipping ?
The garden as a laboratory: the role of domestic gardens as places of scientific exploration in the long 18th century
This is an Accepted Manuscript of an article published by Taylor & Francis in Post-Medieval Archaeology on 24/06/2014, available online: http://www.tandfonline.com/doi/full/10.1179/0079423614Z.00000000054Eighteenth-century gardens have traditionally been viewed as spaces designed for leisure, and as representations of political status, power and taste. In contrast, this paper will explore the concept that gardens in this period could be seen as dynamic spaces where scientific experiment and medical practice could occur. Two examples have been explored in the pilot study which has led to this paper â the designed landscapes associated with John Hunterâs Earlâs Court residence, in London, and the garden at Edward Jennerâs house in Berkeley, Gloucestershire. Garden history methodologies have been implemented in order to consider the extent to which these domestic gardens can be viewed as experimental spaces
Low Energy Thresholds and the Scalar Mass Spectrum in Minimal Supersymmetry
We discuss low energy threshold effects and calculate the sparticle masses in
the context of the Minimal Supersymmetric Standard Model. We pay particular
attention to the top squark and the Higgs mass parameters, and calculate the
top Yukawa corrections, taking into account the successive decoupling of each
particle at its threshold. We discuss the phenomenological implications in the
context of the radiative symmetry breaking scenario.Comment: (CERN-TH.7411, Latex file, 12p, 1fig. not included
Measurement of the B0-anti-B0-Oscillation Frequency with Inclusive Dilepton Events
The - oscillation frequency has been measured with a sample of
23 million \B\bar B pairs collected with the BABAR detector at the PEP-II
asymmetric B Factory at SLAC. In this sample, we select events in which both B
mesons decay semileptonically and use the charge of the leptons to identify the
flavor of each B meson. A simultaneous fit to the decay time difference
distributions for opposite- and same-sign dilepton events gives ps.Comment: 7 pages, 1 figure, submitted to Physical Review Letter
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