Temporal lobe pathology in neurodegenerative disease:a comparative study of eight disorders with special reference to the hippocampus

The temporal lobe is a major site of pathology in a number of neurodegenerative diseases. In this chapter, the densities of the characteristic pathological lesions in various regions of the temporal lobe were compared in eight neurodegenerative disorders, viz., Alzheimer’s disease (AD), Down’s syndrome (DS), dementia with Lewy bodies (DLB), Pick’s disease (PiD), corticobasal degeneration (CBD), progressive supranuclear palsy (PSP), sporadic Creutzfeldt-Jakob disease (sCJD), and neuronal intermediate filament inclusion disease (NIFID). Temporal lobe pathology was observed in all of these disorders most notably in AD, DS, PiD, sCJD, and NIFID. The regions of the temporal lobe affected by the pathology, however, varied between disorders. In AD and DS, the greatest densities of ?-amyloid (A?) deposits were recorded in cortical regions adjacent to the hippocampus (HC), DS exhibiting greater densities of A? deposits than AD. Similarly, in sCJD, greatest densities of prion protein (PrPsc) deposits were recorded in cortical areas of the temporal lobe. In AD and PiD, significant densities of neurofibrillary tangles (NFT) and Pick bodies (PB) respectively were present in sector CA1 of the HC while in CBD, the greatest densities of tau-immunoreactive neuronal cytoplasmic inclusions (NCI) were present in the parahippocampal gyrus (PHG). Particularly high densities of PB were present in the DG in PiD, whereas NFT in AD and Lewy bodies (LB) in DLB were usually absent in this region. These data confirm that the temporal lobe is an important site of pathology in the disorders studied regardless of their molecular ‘signature’. However, disorders differ in the extent to which the pathology spreads to affect the HC which may account for some of the observed differences in clinical dementia.

Neuropathology of Basal Ganglia and its role in the Parkinsonian syndromes with special reference to the Globus pallidus

The globus pallidus, together with the striatum (caudate nucleus and putamen), substantia nigra, nucleus accumbens, and subthalamic nucleus constitute the basal ganglia, a group of nuclei which act as a single functional unit. The basal ganglia have extensive connections to the cerebral cortex and thalamus and exert control over a variety of functions including voluntary motor control, procedural learning, and motivation. The action of the globus pallidus is primarily inhibitory and balances the excitatory influence of other areas of the brain such as the cerebral cortex and cerebellum. Neuropathological changes affecting the basal ganglia play a significant role in the clinical signs and symptoms observed in the ‘parkinsonian syndromes’ viz., Parkinson’s disease (PD), progressive supranuclear palsy (PSP), dementia with Lewy bodies (DLB), multiple system atrophy (MSA), and corticobasal degeneration (CBD). There is increasing evidence that different regions of the basal ganglia are differentially affected in these disorders. Hence, in all parkinsonian disorders and especially PD, there is significant pathology affecting the substantia nigra and its dopamine projection to the striatum. However, in PSP and MSA, the globus pallidus is also frequently affected while in DLB and CBD, whereas the caudate nucleus and/or putamen are affected, the globus pallidus is often spared. This chapter reviews the functional pathways of the basal ganglia, with special reference to the globus pallidus, and the role that differential pathology in these regions may play in the movement disorders characteristic of the parkinsonian syndromes.

The use of the lichen genus Rhizocarpon in lichenometric dating with special reference to Holocene glacial events

Lichenometry is one of the most widely used methods of dating the surface age of substrata including rock surfaces, boulders, walls, and archaeological remains and has been particularly important in dating late Holocene glacial events. Yellow-green species of the crustose genus Rhizocarpon have been the most useful lichens in lichenometry because of their low growth rates and longevity. This review describes: (1) the biology of the genus Rhizocarpon, (2) growth rates and longevity, (3) environmental growth effects, (4) methods of estimating lichen age, (5) the methodology of lichenometry, (6) applications to dating glacial events, and (7) future research. Lichenometry depends on many assumptions, most critically that if the lag time before colonisation of a substratum is known and lichen age can be estimated, then a minimum surface age date can be obtained by measuring the size of the largest Rhizocarpon thallus. Lichen age can be estimated by calibrating thallus size against surfaces of known age (‘indirect lichenometry’), by constructing a growth rate-size curve from direct measurement of growth (‘direct lichenometry’), using radio-carbon (RC) dating, or from lichen ‘growth rings’. Future research should include a more rigorous investigation of the assumptions of lichenometry, especially whether the largest thallus present at a site is a good indicator of substratum age, and further studies on the establishment, development, growth, senescence, and mortality of Rhizocarpon lichens.

Pause intensity:a no-reference quality assessment metric for video streaming in TCP networks

In this paper a full analytic model for pause intensity (PI), a no-reference metric for video quality assessment, is presented. The model is built upon the video play out buffer behavior at the client side and also encompasses the characteristics of a TCP network. Video streaming via TCP produces impairments in play continuity, which are not typically reflected in current objective metrics such as PSNR and SSIM. Recently the buffer under run frequency/probability has been used to characterize the buffer behavior and as a measurement for performance optimization. But we show, using subjective testing, that under run frequency cannot reflect the viewers' quality of experience for TCP based streaming. We also demonstrate that PI is a comprehensive metric made up of a combination of phenomena observed in the play out buffer. The analytical model in this work is verified with simulations carried out on ns-2, showing that the two results are closely matched. The effectiveness of the PI metric has also been proved by subjective testing on a range of video clips, where PI values exhibit a good correlation with the viewers' opinion scores. © 2012 IEEE.

Enterprise management and ERP development:case study of Zoomlion using dynamic enterprise reference grid

The enterprise management approach provides a holistic view of organizations and their related information systems. In order to cope with the globalization, virtualization, and volatile competitive environment, traditional firms are seeking to reconstruct their organizational structures and establish new IS architectures to transform from single autonomous entities into more open enterprises supported by new Enterprise Resource Planning (ERP) systems. This paper reports on ERP engage-abilities within three different enterprise management patterns based on the theoretical foundations of the "Dynamic Enterprise Reference Grid". An exploratory inductive study in Zoomlion using the narrative research approach has been conducted. Also, this research delivers a conceptual framework to demonstrate the adoption of ERP in the three enterprise management structures and points to a new architectural type (ERPIII) for operating in the virtual enterprise paradigm. © 2010 Springer-Verlag.