Experiments and observations on the behaviour and brain of the aging female mouse with special reference to dementia of the Alzheimer type

The objective of this research was to investigate the effects of normal aging and the additional effects of chronic exposure to two experimental diets, one enriched in aluminium, the other enriched in lecithin, on aspects of the behaviour and brain histology of the female mouse. The aluminium diet was administered in an attempt to develop a rodent model of Dementia of the Alzheimer Type (DAT). With normal aging, almost all assessed aspects of behaviour were found to be impaired. As regards cognition, selective impairments of single-trial passive avoidance and Morris place learning were observed. While all aspects of open-field behaviour were impaired, the degree of impairment was directly related to the degree of motoric complexity. Deficits were also observed on non-visual sensorimotor coordination tasks and in olfactory discrimination. Histologically, neuron loss, gliosis, vacuolation and congophilic angiopathy were observed in several of the brain regions/fibre tracts believed to contribute to the control of some of the assessed behaviours. The aluminium treatment had very selective effects on both behaviour and brain histology, inducing several features observed in DAT. Behaviourally, the treatment induced impaired spatial reference memory; reduced ambulation; disturbed olfactory function and induced the premature development of the senile pattern of swimming. Histologically, significant neuron loss and gliosis were observed in the hippocampus, entorhinal cortex, amygdala, medial septum, pyriform and pr-frontal cortex. In addition, the brain distribution of congophilic angiopathy was significantly increased by the treatment. The lecithin treatment had effects on both non-cognitive and cognitive aspects of behaviour. The effects of aging on open-field ambulation and rearing were partially ameliorated by the treatment. A similar effect was observed for single-trial passive avoidance performance. Age-dependent improvements in acquisition/retention were observed in 17-23 month mice and Morris place task performance was improved in 11 and 17 month mice. Histologically, a partial sparing of neurons in the cerebellum, hippocampus, entorhinal cortex and subiculum was observed.

The core executive's approach to regulation:from 'better regulation' to 'risk-tolerant deregulation'

This article examines changes in the New Labour core executive’s approach to regulation and its relationship with risk, through analysing documentary, legislative and press sources concerning approaches to regulatory decision-making. It claims that an initial commitment to ‘better regulation’ has gradually been replaced by explicit support for deregulation. A reduction in the scope of regulation was also promoted by the Thatcher and Major governments. The New Labour core executive shares previous (Conservative) administrations’ concern to include business in deregulatory decision-making. However, the article claims that there is one significant difference in the New Labour deregulatory approach: a new toleration of risk. Deregulation is, now, described as a corrective to regulators’ over-reactions to perceived risks, which, it is claimed, are holding back economic and technological progress. However, this new approach excludes competing views concerning how risk should be regulated. In particular, it does not engage with widespread popular views that governments should continue to protect against risk.

Towards the distributed core for ubiquitous superfast broadband optical access

In this paper, we describe recent architectural and technological advances of the end to end optical network architecture proposed by the DISCUS project (the DIStributed Core for unlimited bandwidth supply for all Users and Services). The two main targets of DISCUS are the principle of equivalence in the access and the reduction of optical-to-electronic conversions in the metro-core network. Technological advances and techno-economic evaluation of Long-Reach Passive Optical Networks (LR-PON), as well as the optimal metro-core node architecture and the required network control plane framework are reported. Network infrastructure sharing challenges are also discussed. © 2014 IEEE.

Highly nonlinear chalcogenide suspended-core fibers for applications in the mid-infrared

Due to their unique dispersion and nonlinear properties, chalcogenide suspended-core fibers, characterized by a few micrometer-sized core suspended between large air-holes by few small glaß struts, are excellent candidates for mid-infrared applications. In the present study the influence of the main croß-section characteristics of the chalcogenide suspended-core fibers on the dispersion curve and on the position of the zero-dispersion wavelength has been thoroughly analyzed with a full-vector modal solver based on the finite element. In particular, the design of suspended-core fibers made of both As2S3 and As2Se3 has been optimized to obtain dispersion properties suitable for the supercontinuum generation in the mid-infrared.