ESTABLISHMENT OF THE ZEBRA MUSSEL DREISSENA POLYMORPHA (PALLAS, 1771) IN LOUGH NEAGH, NORTHERN IRELAND

Five adult Dreissena polymotpha were found on the hull of a boat moored in Kinnego Marina, Lough Neagh, in November 2005; this is the first indication of their presence in this large lake. This finding initiated a survey to determine whether the zebra mussel was present throughout Lough Neagh. Forty-four settled juveniles on debris were found at twenty sites around the lough shore. As a result of these findings a more extensive study was undertaken in October 2006 to examine planktonic and settled stages. Veliger larvae were at densities of 0.0211 veligers per m(-3). Spat collectors showed settlement at six out of the seven sites sampled at a mean density of 523.76 juvenile zebra mussels per m(-2). No adult zebra mussels were found on natural substratum in the lough during the shoreline survey. However, 24 adult zebra mussels, 7.5 mm to 24 mm long, were found on the hull of a boat moored in Lough Neagh.

Stability of 5-aminolevulinic acid in novel non-aqueous gel and patch-type systems intended for topical application.

Aminolevulinic acid (ALA) stability within topical formulations intended for photodynamic therapy (PDT) is poor due to dimerisation to pyrazine-2,5-dipropionic acid (PY). Most strategies to improve stability use low pH vehicles, which can cause cutaneous irritancy. To overcome this problem, a novel approach is investigated that uses a non-aqueous vehicle to retard proton-induced charge separation across the 4-carbonyl group on ALA and lessen nucleophilic attack that leads to condensation dimerisation. Bioadhesive anhydrous vehicles based on methylvinylether-maleic anhydride copolymer patches and poly(ethyleneglycol) or glycerol thickened poly(acrylic acid) gels were formulated. ALA stability fell below pharmaceutically acceptable levels after 6 months, with bioadhesive patches stored at 5°C demonstrating the best stability by maintaining 86.2% of their original loading. Glycerol-based gels maintained 40.2% in similar conditions. However, ALA loss did not correspond to expected increases in PY, indicating the presence of another degradative process that prevented dimerisation. Nuclear magnetic resonance (NMR) analysis was inconclusive in respect of the mechanism observed in the patch system, but showed clearly that an esterification reaction involving ALA and both glycerol and poly(ethyleneglycol) was occurring. This was especially marked in the glycerol gels, where only 2.21% of the total expected PY was detected after 204 days at 5°C. Non-specific esterase hydrolysis demonstrated that ALA was recoverable from the gel systems, further supporting esterified binding within the gel matrices. It is conceivable that skin esterases could duplicate this finding upon topical application of the gel and convert these derivatives back to ALA in situ, provided skin penetration is not affected adversely.

Bimodules over nest algebras and Deddens'

We generalise Dedden's Theorem for nest algebras to nest algebra bimodules. We define an object which extends the Jacobson radical of a nest algebra, and characterose it generalising a theorem of Erdos.

FLEXIBLE OMNIVORY IN DIKEROGAMMARUS VILLOSUS (SOWINSKY, 1894) (AMPHIPODA) - AMPHIPOD PILOT SPECIES PROJECT (AMPIS) REPORT 5

Feeding in Dikerogammarus villosus (Sowinsky, 1894) males was observed in the field and recorded on video in the laboratory. The following feeding modes were recognized: detritus feeding, grazing, particle feeding, coprophagy, predation on benthic and free swimming invertebrates, predation on fish eggs and larvae, as well as feeding on byssus threads of the zebra mussel, Dreissena polymorpha (Pallas, 1771). The feeding methods are described and illustrated with screenshots of video recordings. The very flexible feeding modes of D. villosus, which make diet switches possible, form a trait that must be an important factor in the invasion success of this Ponto-Caspian gammaridean species, and may thus explain for a great deal its high ecosystem impact.

Social Exchange at Work and Emotional Exhaustion: The Role of Personality

Unbalanced social-exchange processes at work have been linked to emotional exhaustion. In addition to organizational factors, individual differences are important determinants of reciprocity perceptions. This study explored whether broad and narrow personality traits were associated with perceived lack of reciprocity (organizational and interpersonal levels), and whether personality moderated the relationship between reciprocity and emotional exhaustion, in a sample of 322 civil servants. Extraversion, agreeableness, emotional stability, internal locus of control, and Type A behavior predicted reciprocity. The relationship between perceived lack of reciprocity with the organization and emotional exhaustion was stronger for individuals reporting lower negative affect or higher extraversion. These findings highlight the importance of personality for understanding perceived reciprocity at work and its impact on emotional exhaustion.

Effects of the Interaction Between Reaction Component of Personal Need for Structure and Role Perceptions on Employee Attitudes in Long-Term Care for Elderly People

This study examined the interaction of reaction component of personal need for structure (reaction to lack of structure, RLS) and role perceptions in predicting job satisfaction, job involvement, affective commitment, and occupational identity among employees working in long-term care for elderly people. High-RLS employees experienced more role conflict, had less job satisfaction, and experienced lower levels of occupational identity than did low-RLS employees. We found individual differences in how problems in roles affected employees' job attitudes. High-RLS employees experienced lower levels of job satisfaction, job involvement, and affective commitment, irrespective of role-conflict levels. Low-RLS employees experienced detrimental job attitudes only if role-conflict levels were high. Our results suggest that high-RLS people benefit less from low levels of experienced role conflicts.