Neural network modeling of memory deterioration in Alzheimer's disease

The clinical course of Alzheimer's disease (AD) is generally characterized by progressive gradual deterioration, although large clinical variability exists. Motivated by the recent quantitative reports of synaptic changes in AD, we use a neural network model to investigate how the interplay between synaptic deletion and compensation determines the pattern of memory deterioration, a clinical hallmark of AD. Within the model we show that the deterioration of memory retrieval due to synaptic deletion can be much delayed by multiplying all the remaining synaptic weights by a common factor, which keeps the average input to each neuron at the same level. This parallels the experimental observation that the total synaptic area per unit volume (TSA) is initially preserved when synaptic deletion occurs. By using different dependencies of the compensatory factor on the amount of synaptic deletion one can define various compensation strategies, which can account for the observed variation in the severity and progression rate of AD

Developing web services in a computational grid environment

Grid and Web services are both hot topics today. In this paper, we will present some ongoing work and planned future work at the Cambridge eScience Centre. After an introduction to these technologies in the context of Grid applications development, we describe two use-cases: a database of results in computational fluid dynamics (CFD) and a small computational Grid for aircraft engineering design. As Grid services are moving towards Web services, we continue to make use of the Globus Toolkit v2.4 (GT2.4), without adopting the Open Grid Services Architecture (OGSA) wholesale. In our scenario, GT2.4 integrates distributed computing resources including HPC and clusters while Web services wrap the scientific code as a service.Proceedings of the IEEE International Conference on Services Computing, Shanghai, September 200

Catalytic RNA and synthesis of the peptide bond

We are studying whether the L-19 IVS ribozyme from Tetrahymena thermophila can catalyze the formation of the peptide bond when it is supplied with synthetic aminoacyl oligonucleotides. If this reaction works, it could give us some insight into the mechanism of peptide bond formation and the origin of coded protein synthesis. Two short oligoribonucleotides, CCCCC and a protected form of CCCCU were prepared; the former was made by the controlled hydrolysis of Poly(C), and the later by multistep chemical synthesis from the protected monomers. The homopentamer was then aminocylated using C-14 labelled Boc-protected glycine imidazolide. This aminoacylated oligo-nucleotide has now been shown to enter the active site of the L-19 IVS, and aminoacyl transfer, and peptide bond formation reactions are being sought. Our synthesis of CCCCU made us aware of the inadequacy of many of the 2'- hydroxyl protecting groups that are in use today and we therefore designed a new 2'- protecting group that is presently being tested

The impact of the mode of thought in complex decisions: intuitive decisions are better

A number of recent studies have reported that decision quality is enhanced under conditions of inattention or distraction (unconscious thought; Dijksterhuis, 2004; Dijksterhuis and Nordgren, 2006; Dijksterhuis et al., 2006). These reports have generated considerable controversy, for both experimental (problems of replication) and theoretical reasons (interpretation). Here we report the results of four experiments. The first experiment replicates the unconscious thought effect, under conditions that validate and control the subjective criterion of decision quality. The second and third experiments examine the impact of a mode of thought manipulation (without distraction) on decision quality in immediate decisions. Here we find that intuitive or affective manipulations improve decision quality compared to analytic/deliberation manipulations. The fourth experiment combines the two methods (distraction and mode of thought manipulations) and demonstrates enhanced decision quality, in a situation that attempts to preserve ecological validity. The results are interpreted within a framework that is based on two interacting subsystems of decision-making: an affective/intuition based system and an analytic/deliberation system

Carneades' quip : Orality, philosophy, wit, and the poetics of impromptu quotation

In spite of a long and influential philosophical career, when Carneades of Cyrene (214-129 BC), head of the Academy in its skeptical phase, died at age eighty-five, he left behind no written works. There were, we are told, some letters extant in Diogenes Laertius' time addressed to Ariarathes, king of Cappadocia, but Carneades' philosophical opinions were conveyed orally and transmitted to posterity in written form only by his students (D.L. 4.65).1 In this respect Carneades resembles not only Pythagoras and Socrates before him and Epictetus later, but also his Skeptic predecessors Pyrrho and Arcesilaus, whose refusal to commit their ideas to writing was a conscious protest against philosophical dogmatism.2/

Quantum Hall induced currents and the magnetoresistance of a quantum point contact

We report an investigation of quantum Hall induced currents by simultaneous measurements of their magnetic moment and their effect on the conductance of a quantum point contact (QPC). Features in the magnetic moment and QPC resistance are correlated at Landau-level filling factors nu=1, 2 and 4, which demonstrates the common origin of the effects. Temperature and non-linear sweep rate dependences are observed to be similar for the two effects. Furthermore, features in the noise of the induced currents, caused by breakdown of the quantum Hall effect, are observed to have clear correlations between the two measurements. In contrast, there is a distinct difference in the way that the induced currents decay with time when the sweeping field halts at integer filling factor. We attribute this difference to the fact that, while both effects are sensitive to the magnitude of the induced current, the QPC resistance is also sensitive to the proximity of the current to the QPC split-gate. Although it is clearly demonstrated that induced currents affect the electrostatics of a QPC, the reverse effect, the QPC influencing the induced current, was not observed

The reception of Homer as oral poetry

For me, one of the most interesting directions in oral tradition studies focuses on the reception of Homeric poetry as oral poetry in classical and later antiquity. The topics and materials for study here are wide-ranging. They include the internalization of Homeric poetics by lyric and elegiac poets; "rhapsodic" variation and conflation of lines in authors who quote Homer; the adaptation of Homeric tags in Cynic street sermons; the pastiche form known as the cento; even the re-use of Homeric poetry in magical incantations, to name just a few avenues of investigation.Not

Magneto-optical determination of the electron-solid phase-boundary

We have obtained a two-dimensional electron-solid phase diagram in the extreme magnetic quantum limit by studying the temperature dependence of the radiative recombination of electrons in a GaAs/AlxGa1-xAs heterojunction with holes bound to a delta-layer, 250 A away in the GaAs, of Be acceptors. The low-energy shoulder to the luminescence line, indicating the presence of the electron solid, is seen to disappear at a filling-factor-dependent critical temperature. We observe no shoulder above a filling factor of 0.25, and the critical temperature falls to below 0.4 K at filling factors 1/5 and 1/7

BIM adoption and implementation for architectural practices

Severe issues about data acquisition and management arise during the design creation and development due to complexity, uncertainty and ambiguity. BIM (Building Information Modelling) is a tool for a team based lean design approach towards improved architectural practice across the supply chain. However, moving from a CAD (Computer Aided Design) approach to BIM (Building Information Modelling) represents a fundamental change for individual disciplines and the construction industry as a whole. Although BIM has been implemented by large practices, it is not widely used by SMEs (Small and Medium Sized Enterprises). Purpose: This paper aims to present a systematic approach for BIM implementation for Architectural SMEs at the organizational level Design/Methodology/Approach: The research is undertaken through a KTP (Knowledge transfer Partnership) project between the University of Salford and John McCall Architects (JMA) a SME based in Liverpool. The overall aim of the KTP is to develop lean design practice through BIM adoption. The BIM implementation approach uses a socio-technical view which does not only consider the implementation of technology but also considers the socio-cultural environment that provides the context for its implementation. The action research oriented qualitative and quantitative research is used for discovery, comparison, and experimentation as it provides �learning by doing�. Findings: The strategic approach to BIM adoption incorporated people, process and technology equally and led to capacity building through the improvements in process, technological infrastructure and upskilling of JMA staff to attain efficiency gains and competitive advantages. Originality/Value: This paper introduces a systematic approach for BIM adoption based on the action research philosophy and demonstrates a roadmap for BIM adoption at the operational level for SME companie