Basic Difference Between Brain and Computer: Integration of Asynchronous Processes Implemented as Hardware Model of the Retina

There exists a common view that the brain acts like a Turing machine: The machine reads information from an infinite tape (sensory data) and, on the basis of the machine's state and information from the tape, an action (decision) is made. The main problem with this model lies in how to synchronize a large number of tapes in an adaptive way so that the machine is able to accomplish tasks such as object classification. We propose that such mechanisms exist already in the eye. A popular view is that the retina, typically associated with high gain and adaptation for light processing, is actually performing local preprocessing by means of its center-surround receptive field. We would like to show another property of the retina: The ability to integrate many independent processes. We believe that this integration is implemented by synchronization of neuronal oscillations. In this paper, we present a model of the retina consisting of a series of coupled oscillators which can synchronize on several scales. Synchronization is an analog process which is converted into a digital spike train in the output of the retina. We have developed a hardware implementation of this model, which enables us to carry out rapid simulation of multineuron oscillatory dynamics. We show that the properties of the spike trains in our model are similar to those found in vivo in the cat retina     

Mixed tenure communities as a policy instrument for educational outcomes in a deprived urban context?

This article considers mixed community strategies, enacted through planning and regeneration policies, as a policy approach to the improvement of educational outcomes in schools. Analysis is undertaken of educational outcomes across secondary schools in Glasgow. The level of owner occupation in the catchment is positively associated with both examination results at S4 and positive destinations post-school, particularly at the more deprived end of the school spectrum. The results suggest that tenure mix may be both directly and indirectly related to school performance, with neighbourhood context effects not being entirely mediated through the school context.     

Stop, look, listen, and think? What young children really do when crossing the road.

This study sought to provide basic information about children's behaviour in realistic traffic situations. Most literature in this area has focused on children's knowledge about road safety or has assessed their behaviour in simulated traffic environments. However, until more is known about what children actually do in traffic environments, our ability to identify the important elements for inclusion in educational programmes remains limited. Fifty-six children, aged 5-6 years, took part in a 'treasure trail' activity in which they were confronted with two road crossings, one at a T-junction with a moving car and the other between parked cars. Children's performance was videotaped and coded for relevant behaviours such as stopping at the kerb, looking for traffic, direction of gaze, and style of crossing (i.e. walking vs. running). Results revealed that performance was extremely poor. Sixty percent of the children failed to stop before proceeding from the kerb onto the road. Looking for oncoming traffic was exhibited by no more than 41% of the sample, dropping to as low as 7% in some instances. When looking did occur, it was initially as likely to be in the inappropriate direction (i.e. to the left) as in the appropriate direction (i.e. to the right). Consideration of individual performance revealed the existence of individual differences within the sample; such differences were relatively stable across the two road crossings. These findings, based on controlled naturalistic tasks and detailed observational methods, build on earlier studies that are generally able to provide only estimated rates of children's behaviour.     

Measurement and analysis of neutron and gamma-ray emission rates,other fusion products,and power in electrochemical cells having Pd cathodes

Results of experiments intended to reproduce cold fusion phenomena originally reported by Fleischmann, Pons, and Hawkins are presented. These experiments were performed on a pair of matched electrochemical cells containing 0.1×9 cm Pd rods that were operated for 10 days. The cells were analyzed by the following means: (1) constant temperature calorimetry, (2) neutron counting and γ-ray spectroscopy, (3) mass spectral analysis of⁴He in effluent gases, and⁴He and³He within the Pd metal, (4) tritium analysis of the electrolyte solution, and (5) x-ray photoelectron spectroscopy of the Pd cathode surface. Within estimated levels of accuracy, no excess power output or any other evidence of fusion products was detected.     

A comparison of the full-wave and WKB solutions of a plane wave with impulsive time variation reflected from a sech2electron-density profile

This communication compares a more general numerical point-to-point transient wave propagation program to a known analytical (full-wave) solution based upon a certain special geometry and ionospheric profile. The main purpose of the comparison is that of using the known analytical results as a test case for the numerical program. The parameters of the ionosphere were chosen to purposively tax the condition of requiring a slowly varying medium in using the Wentzel-Kramer-Brillouin (WKB) method (i.e., the parameters chosen lead to a sporadicE-type layer). With the results favorable for this case, the application of a numerical procedure, based upon the WEB method, to the more slowly varyingFregion would definitely be acceptable. Based upon the full-wave and WKB solutions, results are given in the form of time-domain waveforms due to reflection of a transient wave from the ionosphere.     

A role for lipoxin A₄ as an anti-inflammatory mediator in the human endometrium

Lipoxin A(4) is a lipid mediator that elicits anti-inflammatory and pro-resolution actions via its receptor, formyl peptide receptor 2 (FPR2/ALX). In this study, we aimed to investigate the expression and potential role of lipoxin A(4) and FPR2/ALX in the regulation of inflammation associated with cyclical remodeling of the human endometrium across the menstrual cycle and during early pregnancy. Using quantitative RT-PCR analysis, we found that FPR2/ALX expression is upregulated during the menstrual phase of the cycle and in decidua tissue from the first trimester of pregnancy. We localized the site of expression of FPR2/ALX in menstrual phase endometrium and first-trimester decidua tissue to glandular epithelial cells and cells within the stromal compartment, including cells lining the blood vessels and immune cells. Measurement of serum lipoxin A(4) by ELISA revealed no difference in its levels across the menstrual cycle but an elevation in early pregnancy (P<0.001). We found that lipoxin A(4) was regulated by human chorionic gonadotrophin (hCG) during early pregnancy, because treatment of human decidua tissue with hCG increased lipoxin A(4) release (P<0.01). Finally, we have shown that lipoxin A(4) can suppress phorbol myristate acetate-induced expression of the inflammatory cytokines interleukin 6 and 8 in human endometrium and decidua tissue. These results demonstrate for the first time that lipoxin A(4) and its receptor FPR2/ALX can regulate inflammatory events in the human endometrium and decidua of early pregnancy.