Thermodynamics of MHD flows with axial symmetry

We present strategies based upon extremization principles, in the case of the axisymmetric equations of magnetohydrodynamics (MHD). We study the equilibrium shape by using a minimum energy principle under the constraints of the MHD axisymmetric equations. We also propose a numerical algorithm based on a maximum energy dissipation principle to compute in a consistent way the equilibrium states. Then, we develop the statistical mechanics of such flows and recover the same equilibrium states giving a justification of the minimum energy principle. We find that fluctuations obey a Gaussian shape and we make the link between the conservation of the Casimirs on the coarse-grained scale and the process of energy dissipation

Relativistic Klein-Gordon charge effects by information-theoretic measures

The charge spreading of ground and excited states of Klein-Gordon particles moving in a Coulomb potential is quantitatively analyzed by means of the ordinary moments and the Heisenberg measure as well as by use of the most relevant information-theoretic measures of global (Shannon entropic power) and local (Fisher's information) types. The dependence of these complementary quantities on the nuclear charge Z and the quantum numbers characterizing the physical states is carefully discussed. The comparison of the relativistic Klein-Gordon and non-relativistic Schrodinger values is made. The non-relativistic limits at large principal quantum number n and for small values of Z are also reached.Comment: Accepted in New Journal of Physic

Transport and Magnetic Studies on the Spin State Transition of Pr1-xCaxCoO3 up to High Pressure

Transport and magnetic measurements and structural and NMR studies have been carried out on (Pr1-yR'y)1-xAxCoO3 {R'=(rare earth elements and Y); A=(Ca, Ba and Sr)} at ambient pressure or under high pressure. The system exhibits a phase transition from a nearly metallic to an insulating state with decreasing temperature T, where the low spin (LS) state of Co3+ is suddenly stabilized. For y=0, we have constructed a T-x phase diagram at various values of the external pressure p. It shows that the (T, x) region of the low temperature phase, which is confined to a very narrow region around x=0.5 at ambient pressure, expands as p increases, suggesting that the transition is not due to an order-disorder type one. For the occurrence of the transition, both the Pr and Ca atoms seem to be necessary. The intimate relationship between the local structure around the Co ions and the electronic (or spin) state of Co3+ ions is discussed: For the smaller unit cell volume or the smaller volume of the CoO6 octahedra and for the larger tilting angle of the octahedra, the temperature of the transition becomes higher. The role of the carriers introduced by the doping of the A atoms, is also discussed. By analyzing the data of 59Co-NMR spectra and magnetic susceptibilities of Pr1-xCaxCoO3 the energy separations among the different spin states of Co3+ and Co4+ are roughly estimated.Comment: 15 pages, 15 figures, 2 tables, submitted to J. Phys. Soc. Jp

Organization, Evolution, Cognition and Dynamic Capabilities

Using insights from ‘embodied cognition’ and a resulting ‘cognitive theory of the firm’, I aim to contribute to the further development of evolutionary theory of organizations, in the specification of organizations as ‘interactors’ that carry organizational competencies as ‘replicators’, within industries as ‘populations’. Especially, I analyze how, if at all, ‘dynamic capabilities’ can be fitted into evolutionary theory. I propose that the prime purpose of an organization is to serve as a cognitive ‘focusing device’. Here, cognition has a wide meaning, including perception, interpretation, sense making, and value judgements. I analyse how this yields organizations as cohesive wholes, and differences within and between industries. I propose the following sources of variation: replication in communication, novel combinations of existing knowledge, and a path of discovery by which exploitation leads to exploration. These yield a proposal for dynamic capabilities. I discuss in what sense, and to what extent these sources of variation are ‘blind’, as postulated in evolutionary theory.

The enchanted snake and the forbidden fruit: the ayahuasca ‘fairy tale’ tourist

This ethnographic study increases our understanding of Westerners seeking genuine fairy tale experiences of magic, transformation and enchantment within South American psychedelic ayahuasca tourism. Examining 63 tourists, this study shows how vision-based spirit sensegivers facilitate individuals in exorcising demons, to make sense of themselves as spiritual beings within an enchanted universe. However, and with this potion quickly wearing off upon returning to the West, tourists feel abandoned by their spirits, and disconnected from the fairy lands. Coupled with not wanting to re-experience intense inner tensions from stepping in and out of a fairy tale, further tourism is rejected. As such, ayahuasca tourism becomes a ‘forgotten’ fairy tale, rarely told

Is my memory an extended notebook?

Clark and Chalmers' conception of spatially extended memory is under- pinned by an objectified conception of biological memory. To the extent that this can be identified with a ‘storage’ approach to memory, criticisms of it are well known and an alternative approach, perhaps more suited to an enactive account of cognition, might be one which focuses on remembering as a type of action. In the Otto story the objectification of memory is apparent not only in C&C’s characterization of the notebook but also in the notion that Inga’s memory is notebook-like. Insofar as Inga’s practices, or conceptions, of remembering might be notebook-like this should not be taken as evidence of the existence of an internal store, but could instead be the result of prior interaction with notebook-like artifacts

At the Crossroads of Sustainability: The Natural Recompositioning of Architecture

It is widely acknowledged that the mantra of sustainability has triggered a fundamental reversal in the core of design practice: If the original purpose of architecture was to protect humans from the destructive actions of nature,today it should protect nature from the damaging actions of humans. But sustainable design is far from being a coherent body of fully totalized ideas:it has a broad spectrum of disputing interpretations that oscillate between the deterministic models of energy control and technological efficiencies, and the moralistic and romantic approaches that attempt to see in nature and natural processes a fundamental way to de-escalate the global urban footprint and its associated patterns of consumption. However, mainstream green design has been evolving by progressively absorbing the narrative of deep ecology. Nature has been being integrated into architecture literally, by inserting vegetation onto buildings; digitally, by bringing environmental data into the design process (climate records, wind streams, sun rotation and air flows are computed, modelled and effectually shape architectures), and transcendentally, by claiming that sustainable architecture nurtures “the existing and evolving connections between spiritual and material consciousness.” The acknowledgement of the inexorable affiliation between architecture and the environment is, of course, not exactly new. What is distinctive today is the reification of the role of nature in architecture as an ideological stance, now totally intertwined with state-of-art data processing and the market-driven tools brought by Natural Capitalism. This paper will examine emblematic “green” buildings produced by leading architects such as Pelli Clarke Pelli, William McDonough, Stefano Boeri, Norman Foster and BIG in the light of Tim Morton’s, Slavoj Zizek and Bruno Latour’s critique of nature. It will illustrate how, despite being able to successfully forge new creative freedoms by exploring hybridizations between the domains of design and science, sustainability’s self-righteous “naturalistic” narrative is enabling a vision of the architect as an “expert manager” focused on producing projects of ecologic “beautification” while assumed to be “saving the world,” effectively depoliticizing the architectural practice. Nevertheless, these examples attest that there is a vast and fertile field of ideas to be explored and in this regard it is important to underline that we are still in the embryonic outset of the engagement of architecture with sustainability

Context dependency in risky decision making: Is there a description-experience gap?

When making decisions involving risk, people may learn about the risk from descriptions or from experience. The description-experience gap refers to the difference in decision patterns driven by this discrepancy in learning format. Across two experiments, we investigated whether learning from description versus experience differentially affects the direction and the magnitude of a context effect in risky decision making. In Study 1 and 2, a computerized game called the Decisions about Risk Task (DART) was used to measure people's risk-taking tendencies toward hazard stimuli that exploded probabilistically. The rate at which a context hazard caused harm was manipulated, while the rate at which a focal hazard caused harm was held constant. The format by which this information was learned was also manipulated; it was learned primarily by experience or by description. The results revealed that participants' behavior toward the focal hazard varied depending on what they had learned about the context hazard. Specifically, there were contrast effects in which participants were more likely to choose a risky behavior toward the focal hazard when the harm rate posed by the context hazard was high rather than low. Critically, these contrast effects were of similar strength irrespective of whether the risk information was learned from experience or description. Participants' verbal assessments of risk likelihood also showed contrast effects, irrespective of learning format. Although risk information about a context hazard in DART does nothing to affect the objective expected value of risky versus safe behaviors toward focal hazards, it did affect participants' perceptions and behaviors-regardless of whether the information was learned from description or experience. Our findings suggest that context has a broad-based role in how people assess and make decisions about hazards