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Xjenza Online Vol. 1 Iss. 1 - March 2013
Xjenza Online Vol. 1 Iss. 1 - March 2013 ISSUE: Xjenza Online Vol. 1 Iss. 1 - March 2013



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Editorial
The new Xjenza Online
Giuseppe Di Giovanni
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Article
EARTHQUAKE GROUND-MOTION SIMULATIONS FOR THE MALTESE ARCHIPELAGO
Sebastiano D'Amico, Pauline Galea
Pages: 3 - 10
Abstract | View full article | PDF
Abstract:
The main goal of this paper is to provide earthquake ground motion simulations for particular earthquake scenarios, in terms of ground motion pa- rameters for the Maltese islands. We used a stochastic approach to simulate high-frequency strong-ground motions, using an extended-source model code. This code was developed for earthquake simulations using stochastic nite-fault modelling and a dynamic corner frequency approach. The extended-source model code is a reliable and practical method to simulate ground motion records of moderate and large earthquakes es- pecially in regions where structural damage is expected, but sparse ground motion recordings are available. In this paper, we show that in the Maltese archipelago, the ground motion from the repeat occurrence of his- torically recorded earthquakes, or from other potential sources, coupled with existing geological conditions and building typologies has the potential to cause signi cant structural damage in the area.

Doi: http://dx.medra.org/10.7423/XJENZA.2013.1.01
Article
PITTOSPORUM PIT SCALE, PLANCHONIA ARABIDIS (HEMIPTERA: ASTEROLECANIIDAE) AND ITS LEAF GALLS INDUCED ON PITTOSPORUM TOBIRA IN SOUTHERN ITALY
Alessio Volvas, Chris Malumphy, David Misfud
Pages: 11 - 15
Abstract | View full article | PDF
Abstract:
The morphology of the adult female pittosporum pit scale, Planchonia arabidis, a commonly encountered sap-feeding insect in Europe, is described and illustrated, based on material collected from southern Italy on Pittosporum tobira. Histopatholog- ical observations are made for the rst time on the aforementioned host-plant on which typical pit galls are induced by P. arabidis. Distribution and host-plant data is also provided for this species at a global level.

Doi: http://dx.medra.org/10.7423/XJENZA.2013.1.02
Article
THE SPECTRUM OF ISCHEMIA-INDUCED WHITE MATTER INJURY VARIES WITH AGE
Christian Zammit, Richard Muscat, Mario Valentino
Pages: 16 - 26
Abstract | View full article | PDF
Abstract:
Stroke is a neurological condition that targets the whole range of the human population, from the pre-term infant to the elderly and is a major cause of death worldwide (Ingall 2004). During its lifespan, the brain's vulnerability to hypoxia-ischemia varies. Term infants who su er this insult usually exhibit widespread neuronal injury in the cerebral cortex with a stroke-like distribution of damage (Deng 2008), whereas in pre-term infants immature oligodendrocytes and subplate neurons below the neocortex are most vulnerable and result in Periventricular Leukomalacia (PVL) (Back et al. 2007; McQuillen et al. 2005). The incidence of stroke decreases in young adulthood, but peaks again in the elderly. Moreover, the underlying pathological mechanisms that occur following ischemia are different at each stage. Experimental stroke research on stroke has traditionally focused on grey matter injury, but recent evidence indicates that white matter injury is a critical part of its pathophysiology. In this debilitating condition the mechanisms of ischemia-induced damage di er with age and all cellular components of white matter (axons, oligodendrocytes and astrocytes) are affected. This review paper focuses on the relative vulnerability to ischemia of white matter during the course of development and on our recent ndings of how individual cellular components are affected during each stage.

Doi: http://dx.medra.org/10.7423/XJENZA.2013.1.03
Article
Germination responses in Callitriche truncata Gussone
Jilly Camilleri, Sandro Lanfranco
Pages: 27 - 33
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Abstract:
This study investigated the germination responses of seeds of Callitriche truncata, an obligate hydrophyte that colonises temporary ponds in the Mediterranean, when subjected to different depths of burial and to varying patterns of initial ooding, and to examine the effect of ooding date on the growth and reproduction effort of this plant. All investigations were carried out at two different seed densities in order to investigate whether this factor would exert any effect on germination success and on accumulation of biomass. Seeds germinated from the 'no burial' treatment and from burial under 1 cm of sterile sediment with the rates of germination success declining rapidly with depth of burial. No germination was recorded from seeds buried deeper than 1 cm. The density of seeds per pot did not in uence the results signi cantly. There was no signi cant difference in germination success of seeds subjected to 'Autumn ooding' and 'Winter ooding' treatments or across seed densities. Plants grown during the 'Winter ooding' treatment produced less total biomass and a lower proportion of reproductive biomass at the end of the experiment than seeds grown during the 'Autumn ooding' treatment. Although characterised by lower reproductive success, later ooding still permitted completion of life cycles and restocking of the seed bank. These ndings are generally consistent with the results of previous studies in other temporary waters of the Mediterranean.

Doi: http://dx.medra.org/10.7423/XJENZA.2013.1.04
Article
Medical Diagnostics using Designed Molecules with Sense and Logic
Maria Cardona, Kristina Farrugia, David C. Magri
Pages: 30 - 37
Abstract | View full article | PDF
Abstract:
Luminescent molecules responsive to cations, anions and even small molecules can be designed with the appropriate selectivity and sensitivity for monitoring physiological and pathological levels of analytes. We highlight some recent examples of designed molecules that can sense for a speci c analyte or a combination of analytes in blood and in living cells. Furthermore, we demonstrate how molecules can be designed with built-in algorithms according to principles of Boolean logic to perform information processing. The potential future application of molecular systems able to perform multi-analyte sensing as 'lab-on-a-molecule' systems for medical and environmental diagnostics is also presented.

Doi: http://dx.medra.org/10.7423/XJENZA.2013.1.05
Article
COMPUTATIONALLY EFFICIENT ESTIMATION OF HIGH- DIMENSION AUTOREGRESSIVE MODELS - WITH APPLICATION TO AIR POLLUTION IN MALTA
Luana Chetcuti Zammit, Kenneth Scerri, Maria Attard, Thérése Bajada
Pages: 37 - 45
Abstract | View full article | PDF
Abstract:
The modelling and analysis of spatiotemporal behaviour is receiving wide-spread attention due to its applicability to various scientifi c elds such as the mapping of the electrical activity in the human brain, the spatial spread of pandemics and the diffusion of hazardous pollutants. Nevertheless, due to the complexity of the dynamics describing these systems and the vast datasets of the measurements involved, efficient computational methods are required to obtain representative mathematical descriptions of such behaviour. In this work, a computationally efficient method for the estimation of heterogeneous spatio-temporal autoregressive models is proposed and tested on a dataset of air pollutants measured over the Maltese islands. Results will highlight the computation advantages of the proposed methodology and the accuracy of the predictions obtained through the estimated model.

Doi: http://dx.medra.org/10.7423/XJENZA.2013.1.06
Article
SERPINS: FORM, FUNCTION, AND DYSFUNCTION
Nicholas J. Cassar, Gary J. Hunter
Pages: 45 - 63
Abstract | View full article | PDF
Abstract:
The serpin superfamily of serine protease inhibitors is one of the most ubiquitous and successful classes of inhibitors in the living world. Their unique mechanism of suicide inhibition has led to much research and several important discoveries. They function via rapid incorporation of a reactive centre loop (RCL) within a b-sheet following the former's proteolysis by the target protease: the serpin thus achieves a conformation which is more stable than the native form. Through this conformational change, the target protease structure is distorted and its function disrupted. Alpha-1-antitrypsin (AAT) has often been studied as an archetype for the serpin superfamily, and is discussed in more detail in this review. Of particular interest are the mutant variants of AAT, which have a tendency to polymerise, and thus o er insights into some mechanisms of serpin polymerisation.

Doi: http://dx.medra.org/10.7423/XJENZA.2013.1.07
Article
THE UNIVERSITY OF MALTA (SEISMIC MONITORING AND RESEARCH UNIT), UNIVERSITY OF BASILICATA AND IMAA- CNR (ITALY) OPERATIONS DURING THE 2012 EMILIA SEISMIC SEQUENCE
Sebastiano D'Amico, Maria Rosaria Gallipoli, Marco Mucciarelli,Luigi Vignola
Pages: 63 - 67
Abstract | View full article | PDF
Abstract:
On 20th May 2012 (02:03 UTC), and on 29th May 2012 (07.00 UTC) two major earthquakes occurred in Northern Italy. The two earthquakes caused 27 people to be killed (7 on 20th May and 20 on 29th May), at least 400 injured, and up to 45; 000 homeless in total, with initial estimates placing the total economic loss at several billion Euros. The main goal of this communication is to describe the operations and efforts of several researchers and Institutions during the seismic crises of the Emilia sequence. The acquired data can provide tools to reduce the impact of future earthquakes on the local communities.

Doi: http://dx.medra.org/10.7423/XJENZA.2013.1.08
Article
COST: Matchmaking for Researchers
Janet Mifsud, Claire Bellia
Pages: 68 - 73
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Article
NATIONAL STRATEGY FOR HEALTH RESEARCH AND INNOVATION
Alec Lapira, Nicholas Sammut, Christian Scerri, Gordon Cordina, Janet Mifsud, Jennifer Cassingena Harper, Ramona Saliba Scerri, Nadine Castillo
Pages: 73 - 76
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