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Xjenza Online Vol. 2 Iss. 2 - October 2014
Xjenza Online Vol. 2 Iss. 2 - October 2014 ISSUE: Xjenza Online Vol. 2 Iss. 2 - October 2014



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Editorial
Editorial
Nicholas Sammut
PDF
Article
WanderRep: A reporting Tool for Caregivers of Wandering Persons with Dementia
Colin Cachia, Conrad Attard, Matthew Montebello
Pages: 2 - 7
Abstract | View full article | PDF
Abstract:
Wandering behaviour is regarded as one of the most dicult to manage for Caregivers of Persons with Dementia. It also results in a lot of stress and burden for all caregivers involved, since this behaviour can result in injuries and getting lost. In this research we are proposing a tool which utilizes the currently available Smart Mobile Technologies to focus on the patients' wandering patterns whilst identifying any possible dangers pertaining to the patient. A number of ndings have been collected from this research tool, through a number of studies with both formal and informal caregivers and patients at the St. Vincent de Paul Elderly Nursing Home. These ndings primarily relate to: (1) The bene ts which caregivers perceive when being alerted of danger relating to their patients and (2) the need for further understanding this research area through the collected data. Caregivers are also given the opportunity to give their feedback on a patient's exposure to danger, thus creating a cooperative environment between caregivers of the same patient. Preliminary tests have shown how this system achieves an 89% speci city to danger rate, which de nes the statistical performance of a binary classi cation test, together with showing how caregivers nd this system as a positive way of reducing their burden when caring for wandering patients.

Doi: 10.7423/XJENZA.2014.2.01
Article
Dynamics of Private Social Networks
Jonathan Mifsud, Matthew Montebello
Pages: 8 - 13
Abstract | View full article | PDF
Abstract:
Social networks, have been a signi cant turning point in ways individuals and companies interact. Various research has also revolved around public social networks, such as Twitter and Facebook. In most cases trying to understand what's happening in the network such predicting trends, and identifying natural phenomenon. Seeing the growth of public social networks several corpo- rations have sought to build their own private networks to enable their sta to share knowledge, and expertise. Little research has been done in regards to the value private networks give to their stake holders. This is primarily due to the fact as their name implies, these networks are private, thus access to internal data is limited to a trusted few. This paper looks at a particular online private social network, and seeks to investigate the research possibilities made available, and how this can bring value to the organisation which runs the network. Notwithstanding the limitations of the network, this paper seeks to explore the connections graph between members of the network, as well as understanding the topics discussed within the network. The ndings show that by visualising a social network one can assess the success or failure of their online networks. The Analysis conducted can also identify skill shortages within areas of the network, thus allowing cor- porations to take action and rectify any potential problems.

Doi: 10.7423/XJENZA.2014.2.02
Article
Uniqueness Typing For A Higher-Order Language
Adrian Francalanza, Melanie Zammit
Pages: 14 - 20
Abstract | View full article | PDF
Abstract:
We investigate type-based analysis for a higher-order channel passing language with strong update, whereby messages of a different kind are communicated over the same channel. In order to reason about such pro- grams, our type system employs the concept of uniqueness to be able to assert when it is safe to change the object type a channel. We design a type system based on this concept and prove that our type system is sound, meaning that it only accepts programs that do not produce runtime errors.

Doi: 10.7423/XJENZA.2014.2.03
Article
Formal Proofs for Broadcast Algorithms
Mandy Zammit, Adrian Francalanza
Pages: 21 - 28
Abstract | View full article | PDF
Abstract:
Standard distributed algorithmic solutions to recurring distributed problems are commonly speci ed and described informally. A proper understanding of these distributed algorithms that clari es ambiguities requires formal descriptions. However, formalisation tends to yield complex descriptions. We formally study two broadcast algorithms and present an encoding framework using a process descriptive language and formalise these algorithms and their speci cations using this framework. Following these new formal encodings we discuss correctness proofs for the same algorithms.

Doi: 10.7423/XJENZA.2014.2.04
Article
Monitoring Distributed Systems with Distributed PolyLarva
Ian Cassar, Christian Colombo, Adrian Francalanza
Pages: 29 - 37
Abstract | View full article | PDF
Abstract:
PolyLarva is a language-agnostic runtime veri cation tool, which converts a PolyLarvaScript into a monitor for a given system. While an implementa- tion for PolyLarva exists, the language and its com- pilation have not been formalised. We therefore present a formal implementation-independent model which de- scribes the behaviour of PolyLarvaScript, comprising of the LarvaScript grammar and of a set of operational semantics. This allows us to prove important proper- ties, such as determinism, and also enables us to reason about ways of re-designing the tool in a more scalable way. We also present a collection of denotational map- pings for LarvaScript converting the constructs of our grammar into constructs of a formal actor-based model, thus providing an Actor semantics for LarvaScript. We are also able to prove certain correctness properties of the denotational translation such as that the denoted Actors behave in a way which corresponds to the behaviour de- scribed by our implementation-independent model. We nally present DistPolyLarva, a prototype implementa- tion of the distributed PolyLarva tool, which implements the new actor-based semantics over a language that can na- tively handle distribution and concurrency called Erlang.

Doi: 10.7423/XJENZA.2014.2.05
Article
Warpage issues in large area mould embedding technologies
Russell Farrugia, Ivan Grech, Owen Casha, Joseph Micallef, Edward Gatt, Roseanne Duca, Conrad Cachia
Pages: 38 - 43
Abstract | View full article | PDF
Abstract:
The need for higher communications speed, heterogeneous integration and further miniaturisation have increased demand in developing new 3D integrated packaging technologies which include wafer-level moulding and chip-to-wafer interconnections. Wafer-level moulding refers to the embedding of multiple chips or heteroge- neous systems on the wafer scale. This can be achieved through a relatively new technology consisting of ther- mal compression moulding of granular or liquid epoxy moulding compounds. Experimental measurements from compression moulding on 8" blank wafers have shown an unexpected tendency to warp into a cylindrical-shape following cooling from the moulding temperature to room temperature. Wafer warpage occurs primarily as a result of a mismatch between the coefficient of thermal expansion of the resin compound and the Si wafer. This paper will delve into possible causes of such asymmetric warpage related to mould, dimensional and material characteristics using nite element (FE) software (ANSYS Mechanical). The FE model of the resin on wafer deposition will be validated against the measurement results and will be used to deduce appropriate guidelines for low warpage wafer encapsulation.

Doi: 10.7423/XJENZA.2014.2.06
Article
Neuropathology and Neuropharmacology of Monoaminergic Systems
Rona R Ramsay, Philippe De Deurwaerdère
Pages: 44 - 47
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Article
Annual Meeting of the COST ACTION CM1103
Philippe De Deurwaerdère
Pages: 48 - 100
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Article
Representational Momentum and the Human Face: an empirical note
Ian M. Thornton
Pages: 101 - 110
Abstract | View full article | PDF
Abstract:
Recent evidence suggests that observers may anticipate the future emotional state of an actor when viewing dynamic expressions of emotion, consistent with the notion of representational momentum. The current paper presents data that con icts with these previous studies, nding instead that memory for the nal frame of an emotional video tends to be shifted back in the direction of the rst frame. While simple methodological issues may explain this difference (e.g., the use of morph sequences in previous studies versus naturalistic expressions here) a more theoretically interesting possibility is also considered. Speci cally, recent studies of ensemble representations have shown that observes can rapidly extract the average expression from a display of up to 20 faces. It is suggested that the need to predict versus the need to maintain a stable estimate of the current state often compete when we interact with dynamic stimuli. Our memory for the nal expression on an emotional face may be particularly sensitive to task demands and response timing, thus coming to reflect different solutions to this anticipation-averaging con ict depending on the precise experimental scenario.

Doi: 10.7423/XJENZA.2014.2.09
Article
Viscosity of liquid GaxNi100-x alloys
Andriy Yakymovych, Stepan Mudry
Pages: 111 - 114
Abstract | View full article | PDF
Abstract:
We studied the viscous properties of molten GaxNi100-x alloys in the concentration region between two peritectic points (77 < x < 94). The measurements of the viscosity coefficient were carried out using an oscillating crucible method. Temperature dependence of viscosity revealed anomalous behavior in the vicinity of the melting point, particularly for the Ga80Ni20 melt. This feature was analyzed, taking into account the formation of clusters. We show that the formation of chemically ordered clusters is the main reason for the atypical behavior of the dependence of viscosity on temperature and concentration. The obtained results are in agreement with structural parameters obtained from X-ray di raction.

Doi: 10.7423/XJENZA.2014.2.10
Article
A Fruitful fly forward: The role of the fly in drug discovery for neu- rodegeneration
Michelle Briffa, Neville Vassallo, Ruben J. Cauchi1
Pages: 115 - 126
Abstract | View full article | PDF
Abstract:
Neurodegenerative diseases such as Alzheimer's disease (AD), Parkinson's disease (PD) and Huntington's disease (HD) are increasing in prevalence and the need for novel disease-modifying therapies is critical. Identifying compounds that modify disease progression has been a struggle - mainly due to the insufficient knowledge regarding the underlying pathophysiological mechanisms of these diseases. Traditional high-throughput screening in vitro have previously identi ed positive hits. However, subsequent validation experiments in vivo, rendered them ineffective and/or toxic. Drosophila models of neurodegenerative disease can be e ectively exploited in drug screens for the identi cation of compounds and target disease mechanisms. This review sheds light on how Drosophila models of neurodegeneration can aid the therapeutic discovery process through the use of chemical and genetic suppressor/enhancer screens and other existing techniques. Integrating Drosophila models of neurodegeneration to the drug discovery process holds great promise for the enhanced rate of therapeutic-modifying compound discovery.

Doi: 10.7423/XJENZA.2014.2.11
Article
Select polyphenols protect mitochondria against amyloid aggregates in Alzheimer and Parkinson diseases
Mario Caruana, Neville Vassallo
Pages: 127 - 135
Abstract | View full article | PDF
Abstract:
Alzheimer and Parkinson diseases are agerelated neurodegenerative disorders in which formation of amyloid aggregates by amyloid-beta (Abeta) and a-synuclein (aS) proteins, respectively, are recognised critical events that occur early in the disease process. These aggregates cause disruption of mitochondrial function in neurons, initiating a pathophysiological cascade leading to bio-energetic collapse and ultimately neuronal cell death. The detailed mechanisms are, however, largely unknown. In vitro studies in our laboratory aimed to, (i) investigate destabilisation of mitochondrial phospholipid membranes by these amyloid aggregates and, (ii) explore the protective effect of select polyphenolic compounds on mitochondria. Exposure of mitochondria, isolated from human neuroblastoma SH-SY5Y cells, to amyloid aggregates induced a strong and dose-dependent release of cytochrome c, re ecting damage to the outer and/or inner mitochondrial membranes. Importantly, targeting of aggregates to mitochondria was shown to be dependent upon cardiolipin, a mitochondria-speci c phospholipid known to play a critical role in launching apoptosis. Moreover, the ability of amyloid aggregates to damage mitochondrial membranes was con rmed using a liposome permeabilisation assay. Finally, we found that the polyphenol compounds morin, rosmarinic acid, epigallocatechingallate and black tea extract were potent mito-protectants, and may thus delay the onset of neurodegenerative diseases.

Doi: 10.7423/XJENZA.2014.2.12
Article
A 10 year review of the number of bovine dairy holdings and the dairy bovine population on the Maltese Islands
Mauro Buttigieg, Matteo Gianesella, Andrew James
Pages: 136 - 143
Abstract | View full article | PDF
Abstract:
The process of identi cation and registra- tion of bovines and bovine holdings on the Maltese Islands has been computerised since 2002, with the introduction of the National Livestock Database of Malta. This is a computerised and centralised system which has made collection, management and analysis of data possible. The aims of this paper were to study in detail ten year trends in the number of bovine dairy holdings together with the bovine population on these holdings and to compare these trends with those reported in other European countries. Six trends related to the number of bovine dairy holdings and their bovine population were analysed in the study. The general trends showed that there was a signi cant decrease in the number of dairy holdings, in the bovine population and in the number of female bovines greater than 2 years of age during the study period. The average herd size and the average number of females greater than 2 years of age on the dairy holdings showed no statistically signi cant changes. On the other hand, a signi cant increase in the ratio of female to male bovines was registered on these holdings.

Doi: 10.7423/XJENZA.2014.2.13
Article
Measuring β-cell function in vivo to understand the pathophysiology of type 2 diabetes
Luca P. Farrugia, Adrian Vella MD
Pages: 144 - 150
Abstract | View full article | PDF
Abstract:
Diabetes arises when insulin secretion is inadequate for the prevailing metabolic conditions. As such appropriate measurement of β-cell function is necessary for a better understanding of the pathophys- iology of prediabetes and diabetes. Unfortunately this is not a straightforward process and requires utilization of mathematical modelling to best appreciate its complexities. This is because insulin concentrations in the plasma represent a balance between the processes of secretion, hepatic extraction and clearance. In isolation such simple measures reveal very little about β-cell function. Moreover, since insulin lowers glucose accounting for the effect of the former on the latter it is a key part of understanding insulin action. The devel- opment of the minimal model has allowed simultaneous measurement of the dynamic relationship between insulin secretion and insulin action and produces a quantitative number { the Disposition Index { which quanti es β-cell function. At present this remains the best functional measure of islet health, however, it may not capture other phenotypes such as β-cell senescence or the effect of incretin hormones on β-cell function. Future ongoing development and interaction with other technologies, such as functional imaging, should enhance the contribution of this functional testing to the prevention, treatment and understanding of type 2 diabetes.

Doi: 10.7423/XJENZA.2014.2.14
Article
2014 Science in the House with Members of Parliament
David Magri
Pages: 151 - 152
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Article
In memory of Prof. Giuseppe Amato (1944-2004)
Giuseppe Crescimanno
Pages: 153 - 154
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