Biology and interspecific interactions of the alien crab Percnon gibbesi in the Maltese Islands

Spatial and bathymetric distribution, population density, habitat preferences, fecundity, breeding season and interspecific interactions of the alien grapsoid crab Percnon gibbesi (H. Milne-Edwards, 1853) from the Maltese Islands (Malta and Gozo) are compared among localities in the Mediterranean where established populations have been reported since 1999. In the Maltese Islands, habitat preferences and bathymetric distribution were similar to those in other Mediterranean localities. Spatial distribution was found to be limited by the availability of the boulder habitat in which this crab nearly always occurs. Fecundity was higher in the Maltese Islands than in Linosa and Lampedusa, the breeding season lasting from the end of May until September. On Maltese shores the habitat of the alien overlapped with that of the native grapsid Pachygrapsus marmoratus (Fabricius, 1787) (Crustacea: Brachyura: Grapsoidea) and, to a lesser extent, that of the native xanthid Eriphia verrucosa (Forska°l, 1775). Laboratory studies to assess the possible interactions of the alien species with P. marmoratus suggest that the latter shows a competitive advantage over P. gibbesi, since 80.8% of encounters between the two species were initiated by P. marmoratus, and in 80% of the encounters it prevailed. This suggests that P. marmoratus is unlikely to be excluded from its natural habitat by the alien species, and that significant spatial resource partitioning on the part of P. marmoratus is unlikely to occur.peer-reviewe

The Long March or Bold Strokes : Comparing Strategies for Adopting EVS Learning Technology at a UK University

In recent years there has been much encouragement to investigate the use of classroom technologies to enhance the student learning experience especially in the STEM subjects but now extending across other subject areas as well. A typical classroom technology is electronic voting system (EVS) handsets which allow a lecturer to invite students to vote for their choice from a selection of given answers. Recently, a medium-size UK University has purchased over 9000 EVS handsets for use across the academic Schools as an innovative means for supporting formative and summative testing. Numerous training and support sessions have been provided to staff with the intention of supporting new and experienced users and increasing the take up by academics. As noted in earlier research reported at ECEL 2013, the student feedback was very positive for the use of EVS for formative activities, and less so, for its use in summative assessment. A recent review of the trends of EVS adoption at the University has been undertaken to inform decision-making and future use and support for the technology. One aspect of this review has considered the effectiveness of the strategies adopted by different academic Schools. EVS adoption and use across the University has been compared and placed within Rogers’ theory of the diffusion of innovation. This paper further considers a set of six different strategies adopted for EVS use by academic Schools. They have been categorised according to several variables, including their choice of speed of uptake and the number of handsets in use. The inherent strengths and possible weaknesses of the approaches adopted are considered. Among the questions raised were, does a strategy of large-scale technology adoption over a short time period indicate a greater likelihood of long term engagement and ultimate adoption of the technology? Or, does a longer elapsed time taken for a gradual purchase and adoption of EVS technology suggest a greater inclination for the embedding of technology for enhancing learning? What other success factors should be considered alongside the training and support provided for technology adoption to enhance the likelihood of long term adoption of classroom technologies? The discussion provides a comparison of six different strategies identified across the university and the rationale behind them and then proposes a set of strategy choices which can lead to a greater likelihood of successful adoption of classroom technology

Modelling drug coatings: A parallel cellular automata model of ethylcellulose-coated microspheres

Pharmaceutical companies today face a growing demand for more complex drug designs. In the past few decades, a number of probabilistic models have been developed, with the aim of improving insight on microscopic features of these complex designs. Of particular interest are models of controlled release systems, which can provide tools to study targeted dose delivery. Controlled release is achieved by using polymers with different dissolution characteristics. We present here an approach for parallelising a large-scale model of a drug delivery system based on Monte Carlo methods, as a framework for Cellular Automata mobility. The model simulates drug release in the gastro-intestinal tract, from coated ethylcellulose microspheres. The objective is high performance simulation of coated drugs for targeted delivery. The overall aim is to understand the importance of various molecular effects with respect to system evolution over time. Important underlying mechanisms of the process, such as erosion and diffusion, are described

Nonassociative differential geometry and gravity with non-geometric fluxes

We systematically develop the metric aspects of nonassociative differential geometry tailored to the parabolic phase space model of constant locally non-geometric closed string vacua, and use it to construct preliminary steps towards a nonassociative theory of gravity on spacetime. We obtain explicit expressions for the torsion, curvature, Ricci tensor and Levi-Civita connection in nonassociative Riemannian geometry on phase space, and write down Einstein field equations. We apply this formalism to construct R-flux corrections to the Ricci tensor on spacetime, and comment on the potential implications of these structures in non-geometric string theory and double field theory.Comment: 50 pages; v2: corrected comparison of curvature to ref. [14]; v3: clarifying comments added; Final version to be published in JHE

Penetrating the air-liquid interface is the key to colonization and wrinkly spreader fitness

In radiating populations of Pseudomonas fluorescens SBW25, adaptive wrinkly spreader (WS) mutants are able to gain access to the air–liquid (A–L) interface of static liquid microcosms and achieve a significant competitive fitness advantage over other non-biofilm-forming competitors. Aerotaxis and flagella-based swimming allows SBW25 cells to move into the high-O2 region located at the top of the liquid column and maintain their position by countering the effects of random cell diffusion, convection and disturbance (i.e. physical displacement). However, wild-type cells showed significantly lower levels of enrichment in this region compared to the archetypal WS, indicating that WS cells employ an additional mechanism to transfer to the A–L interface where displacement is no longer an issue and a biofilm can develop at the top of the liquid column. Preliminary experiments suggest that this might be achieved through the expression of an as yet unidentified surface active agent that is weakly associated with WS cells and alters liquid surface tension, as determined by quantitative tensiometry. The effect of physical displacement on the colonization of the high-O2 region and A–L interface was reduced through the addition of agar or polyethylene glycol to increase liquid viscosity, and under these conditions the competitive fitness of the WS was significantly reduced. These observations suggest that the ability to transfer to the A–L interface from the high-O2 region and remain there without further expenditure of energy (through, for example, the deployment of flagella) is a key evolutionary innovation of the WS, as it allows subsequent biofilm development and significant population increase, thereby affording these adaptive mutants a competitive fitness advantage over non-biofilm-forming competitors located within the liquid column

Information exchange and future plans of Slovenian cattle farmers under EU policies

After accession to EU, farmers in the new-member states have to adjust to the EU agricultural policies and market. In Slovenia an analysis is made of the farm development plans and information exchange under quota and CAP. Three research questions were addressed: what information is received and how; how does the farmer prefer to receive information and what kind; how to make decisions to react to the new EU policies concerning farm management and future plans. These questions were linked to the base variables, being the farm and farmers’ characteristics. As tool a questionnaire was distributed to dairy farmers. 1114 questionnaires, 22% of the distributed ones have been returned anonymously, implying that 11% of the dairy farmers’ population is part of the analysis. It appeared that the research sample of farmers used represents the more future oriented farmers. As main factors describing the farm and farmers’ characteristics were found farm size, age and number of other activities than dairy. Results show that nearly all farmers did receive information about some specific aspects of the quota system. Communication channels dealing with this administrative info and also with farm management advice are divers, but frequency of direct contact with advisors may be less than predicted. Results also indicate a very significant demand for info about strategic planning, farm management aspects and EU premium programs, especially about CAP general policies and milk premiums, and a considerable activity in farm planning. About 40% of farmers choose for keeping the farm business the same and 50% intend to develop the farm further.CAP, Slovenian cattle farmers, information, decisions, future plans, Community/Rural/Urban Development, Q18,

AdS-inspired noncommutative gravity on the Moyal plane

We consider noncommutative gravity on a space with canonical noncommutativity that is based on the commutative MacDowell-Mansouri action. Gravity is treated as gauge theory of the noncommutative $SO(1,3)_\star$ group and the Seiberg-Witten (SW) map is used to express noncommutative fields in terms of the corresponding commutative fields. In the commutative limit the noncommutative action reduces to the Einstein-Hilbert action plus the cosmological term and the topological Gauss-Bonnet term. After the SW expansion in the noncommutative parameter the first order correction to the action, as expected, vanishes. We calculate the second order correction and write it in a manifestly gauge covariant way.Comment: 22 pages, no figures, final versio

Observations on the alien crab Percnon gibbesi (Decapoda, Brachyura, Grapsidae) from the Maltese Islands

A preliminary account on habitat preferences, bathymetric distribution, population density, and aspects of the reproductive biology of the alien grapsid Percnon gibbesi in the Maltese Islands is given. This alien was first recorded from Malta in 2001 and has since established breeding populations in suitable habitats throughout the Maltese islands where of its preferred habitat types, upper infralittoral boulder fields or rock faces with a sparse algal cover, are available. The crab breeds in summer and recruits in winter. Female crabs may produce up to 30,000 eggs per spawning. Interactions with the native grapsid Pachygrapsus marmoratus were observed.peer-reviewe

A critical review of records of alien marine species from the Maltese Islands and surrounding waters (Central Mediterranean)

An updated list of alien marine species recorded from the Maltese Islands and surrounding waters, compiled from scientific and ‘grey’ literature and from authenticated unpublished reports to the authors, is presented. The listed species are classified in one of four categories as regards establishment status: established, casual, invasive and questionable. Doubtful records are listed as ‘?’. A total of 48 species, including nine dubious ones, are included in the list. Of the accepted records, 64% are established, of which 15.4% are invasive, 18% are casual and 18% are questionable. The most represented groups are molluscs (14 species), fish (13 species) and macrophytes (10 species). Six species are classified as invasive in Maltese waters: Lophocladia lallemandii, Womersleyella setacea, Caulerpa racemosa var. cylindracea, Percnon gibbesi, Fistularia commersonii and Sphoeroides pachygaster; impacts of some of these species on local ecosystems are discussed. Since the early 1900s, there has been an increasing trend in the number of alien marine species reported from the Maltese Islands. Transportation via shipping and in connection with aquaculture, as well as the range expansion of Lessepsian immigrants, appear to be the most common vectors for entry, accounting for 20%, 11% and 32% respectively of the alien species included in this review. The general warming trend of Mediterranean waters and increasing marine traffic may be facilitating the spread of warm-water Atlantic and Indo-Pacific species to the central Mediterranean, including the Maltese Islands.peer-reviewe