On the neural computation of utility

The rewarding effect produced by electrical stimulation of the lateral hypothalamus can compete and summate with gustatory rewards. However, physiological manipulations, such as sodium depletion and the accumulation of an energy-rich solution in the gut, can alter the rewarding impact of the gustatory stimuli without producing substantial changes in the rewarding effect of the electrical stimulation. On the basis of their competition and summation, it is argued that the artificial and natural rewards are evaluated in a common currency, represented in an aggregate firing-rate code. Such a code would make it possible for the synchronous, spatially contiguous pattern of neural firing induced by the electrode to simulate a signal normally produced by asynchronous, spatially distributed activity. It is suggested that a unidimensional code of this sort is employed to represent the utility of a goal object. In order for physiological feedback to alter the utility of one natural reward, such as sucrose, without changing the utility of a second natural reward, such as a salt solution, the physiological feedback signals must enter into the computation of utility at a stage of processing in which the representations of the two natural rewards are distinct. However, orderly choice between such rewards implies that their utilities are expressed ultimately in a common neural currency. That physiological feedback alters the rewarding effects of the gustatory stimuli suggests that the physiological feedback signals modulate the value of such natural stimuli at a stage of processing prior to their translation into a common currency. In contrast, physiological feedback would fail to alter the rewarding effect of the electrical stimulation if the electrically evoked signal is injected at a later stage processing, a stage in which different rewards are represented in a common currency. In this view, the signal injected by the electrical stimulation mimics the utility of a natural stimulus but not its sensory quality

Book Review: governance in pacific Asia: political economy and development from Japan to Burma

In his latest book, Peter Ferdinand discusses the increasing economic integration of the Pacific Asian region as well as its impact on global affairs. Kent Deng is impressed by the breadth of the book’s coverage and the way it rethinks the once narrowly conceived boundaries of Asia

Leading careers education information advice and guidance (CEIAG) in secondary schools

This report summarises the findings of a set of six case studies, undertaken during November 2010, which explored the effective leadership of careers education information advice and guidance (CEIAG) in a small sample of secondary schools in England. The findings indicate that effective CEIAG is an extremely important component of school provision as it impacts upon students’ aspirations, achievement and therefore potentially their life chances and social mobility. The report describes different curriculum models, with the integration of CEIAG across the curriculum as the preferred approach allied to a strong emphasis on partnership working. The leadership and management of CEIAG follow a distributed model with staff operating at a variety of levels to secure its development and implementation. There is significant evidence of this model combining the skills of both teaching and non-teaching staff. The importance of strategic vision, continuing professional development and monitoring and evaluation is highlighted as substantial. The report concludes with a set of key message for both school leaders and policymakers

X ray timing observations and gravitational physics

Photon-rich x ray observations on bright compact galactic sources will make it possible to detect many fast processes that may occur in these systems on millisecond and submillisecond timescales. Many of these processes are of direct relevance to gravitational physics because they arise in regions of strong gravity near neutron stars and black holes where the dynamical timescales for compact objects of stellar mass are milliseconds. To date, such observations have been limited by the detector area and telemetry rates available. However, instruments such as the proposed X ray Large Array (XLA) would achieve collecting areas of about 100 sq m. This instrument has been described elsewhere (Wood and Michelson 1988) and was the subject of a recent prephase A feasibility study at Marshall Space Flight Center. Observations with an XLA class instrument will directly impact five primary areas of astrophysics research: the attempt to detect gravitational radiation, the study of black holes, the physics of mass accretion onto compact objects, the structure of neutron stars and nuclear matter, and the characterization of dark matter in the universe. Those observations are discussed that are most directly relevant to gravitational physics: the search for millisecond x ray pulsars that are potential sources of continuous gravitational radiation; and the use of x ray timing observations to probe the physical conditions in extreme relativistic regions of space near black holes, both stellar-sized and supermassive

A damage-plasticity model for the dynamic failure of concrete

A constitutive model based on the combination of damage mechanics and plasticity is developed to analyse concrete structures subjected to dynamic loading. The aim is to obtain a model, which requires input parameters with clear physical meanings. The model should describe the important characteristics of concrete subjected to multiaxial and rate-depending loading. This is achieved by combining an effective stress based plasticity model with an isotropic damage model based on plastic and elastic strain measures. The model response in tension, uni-, bi- and tri-axial compression is compared to experimental results in the literature.Comment: Preprint. Submitted to Eurodyn 2011, 8th International Conference on Structural Dynamics, Leuven, Belgium, 201

Henri Temianka Correspondence; (kent)

This collection contains material pertaining to the life, career, and activities of Henri Temianka, violin virtuoso, conductor, music teacher, and author. Materials include correspondence, concert programs and flyers, music scores, photographs, and books.https://digitalcommons.chapman.edu/temianka_correspondence/3837/thumbnail.jp