7,987 research outputs found

    The first use of Fulton's K for assessing and comparing the conditions of inter-tidal fish populations

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    Fulton's K condition factor was applied, for the first time, to inter-tidal specimens of the shanny (Lipophrys pholis) and long-spined scorpion fish (Taurulus bubalis) from two English rocky shore and two Welsh rocky shore sites during summer 2010 and winter 2011. As both species contribute to the diet of commercial species such as cod (Gadus morhua) and near-threatened species such as the European otter (Lutra lutra), their condition may affect that of these predators. Fulton's K found that inter-tidal Welsh fish maintained a ‘good’ condition between seasons, whereas the inter-tidal English fish were in a poorer condition during winter. Although condition also changed amongst the sites on each coast, further studies are needed into fish morphologies, environmental parameters, prey availabilities and abundances, and fish specimen sex and maturities

    Exploring women’s perspectives of living with mental illness, stigma, and receiving community services

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    According to the Canadian Mental Health Association (CMHA) (2015), one in five individuals will experience mental illness personally, which means that all Canadians will be indirectly (or directly) influenced by mental illness at some point in their life. Unfortunately, due to historical trends and negative stereotypes mental illness has become heavily stigmatized (Camp, Finlay, and Lyons, 2002; Chernomas, Clarke, and Chisholm, 2000; Link, Struening, Neese-Todd, Asmussen, and Phelan, 2001; Sands, 2009; Szeto, Luong & Dobson, 2013). Although many studies have assessed the relationship between mental illness and stigma, little research has included a gender lens when exploring these topics. Therefore, the primary research objective of the current study is to explore women’s perspectives of living with mental illness, stigma, and receiving community services. In total, five women from the Kitchener, Waterloo, and Cambridge area participated in the study. Similar to the literature, results found that the women experienced feelings of loneliness and sadness due to their mental illness diagnosis and the stigma they experienced from friends, family, and service staff. Some women talked about being relieved to have a label or diagnosis for their illness, however, the majority of their narratives suggested that living with a mental illness is difficult due to the internal and external stigma they experience. Findings from this study have implications for contributing to the field of social work, improving service delivery within various healthcare facilities, and future research

    Discrete conventional signalling of a continuous variable

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    In aggressive interactions, animals often use a discrete set of signals, while the properties being signalled are likely to be continuous, for example fighting ability or value of victory. Here we investigate a particular model of fighting which allows for conventional signalling of subjective resource value to occur. The result shows that neither perfect nor no signalling are evolutionarily stable strategies (ESSs) in the model. Instead, we find ESSs in which partial information is communicated, with discrete displays signalling a range of values rather than a precise one. The result also indicates that communication should be more precise in conflicts over small resources. Signalling strategies can exist in fighting because of the common interest in avoiding injuries, but communication is likely to be limited because of the fundamental conflict over the resource. Our results reflect a compromise between these two factors. Data allowing for a thorough test of the model are lacking; however, existing data seem consistent with the obtained theoretical results

    An analogue of the Magnus problem for associative algebras

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    We prove an analogue of the Magnus theorem for associative algebras without unity over arbitrary fields. Namely, if an algebra is given by n+k generators and k relations and has an n-element system of generators, then this algebra is a free algebra of rank n

    External morphology of eyes and Nebenaugen of caridean decapods–ecological and systematic considerations

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    Most caridean decapods have compound eyes of the reflecting superposition kind, and additionally some possess an accessory eye-like organ of unknown function, also referred to as the nebenauge.We examined 308 caridean genera to assess the general morphology of the eye, rostrum length, eye diameter and the presence or absence and, when present, the diameter of the nebenauge.We have attempted to relate these data to ecological and taxonomic considerations.We consider there to be 6 distinct eye types based on the margin between the eyestalk and cornea. The presence of nebenaugen appears to be generally linked to an active lifestyle, as evidenced by the fact that species that have nebenaugen tend to have larger eyes and are more likely to have a distinct rostrum.We suggest that the inconsistencies in its presence/absence under both systematic and ecological lenses may indicate that when present it has various roles relating to behavioural and physiological rhythms

    Linking eye design with host symbiont relationships in pontoniine shrimps (crustacea, decapoda, palaemonidae)

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    Symbiosis is prevalent in the marine environment with many studies examining the effects of such interactions between host and symbiont. Pontoniine shrimps are a group whose ecology is characterised by symbiotic interactions. This investigation examines the gross morphology of Pontoniinae compound eyes and superficial optical parameters with reference to their symbiotic relationship or lifestyle category; free-living, ectosymbiont, endosymbiont (bivalves) or endosymbiont (non-bivalves). The eye morphologies of free-living and ectosymbiotic species are very similar, yet differ from both forms of endosymbiotic species. Endosymbionts have significantly smaller and simpler eyes with larger facets and bigger interommatidial angles and eye parameters for increased sensitivity levels. However bivalve endosymbionts form an intermediary group between non-bivalve endosymbionts and ectosymbionts as a result of their more active lifestyle. The accessory eye or "nebenauge", although of uncertain function, commonly occurs in free-living Pontoniinae species but rarely in endosymbionts apart from in more primitive species. The variation in morphology reflects tensions between functional requirements and ecological pressures that have strongly influenced eye design in Pontoniinae. © 2014 Dobson et al

    Thermodynamics and Bending Energetics of Microemulsions

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    A comprehensive, yet simple, theoretical model for droplet microemulsions is presented. The model combines thermodynamics of self-assembly with bending elasticity theory and relates microemulsion properties, such as average droplet size, polydispersity, interfacial tension and solubilisation capacity with the three bending elasticity constants, spontaneous curvature (H 0), bending rigidity (kc) and saddle-splay constant (k¯c). In addition, the self-association entropy constant (ks) explicitly determines various microemulsion properties. The average droplet size is shown to increase with increasing effective bending constant, defined as keff=2kc+k¯c+ks, as well as with decreasing magnitudes of H0. The polydispersity decreases with increasing values of keff, but does not at all depend on H0. The model predicts ultra-low interfacial tensions, the values of which decrease considerably with increasing droplet radius, in agreement with experiments. The solubilisation capacity increases as the number of droplets is increased with increasing surfactant concentration. In addition, an enhanced solubilisation effect is obtained as the size of the droplets increases with increasing surfactant concentration, as a result of self-association entropy effects. It is demonstrated that self-association entropy effects favour smaller droplet size as well as larger droplet polydispersity
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