Elements and stable isotopes as tracers for sleeper shark biology and the Iceland marine food web

Stable isotope studies often rely on only two tracers (usually [delta] 13C and [delta]15N) to study marine ecosystems, which are inherently complex. The ability of elements to act as additional tracers of ecological processes in marine organisms and in a marine food web was investigated. The element analysis of two sleeper shark species, Pacific (\u27Somniosus pacificus\u27) and Greenland (\u27Somniosus microcephalus\u27), collected from different ecosystems demonstrated that elements are useful indicators of physiological and exposure differences between closely related species. The Greenland shark\u27s food web about Iceland was more clearly resolved concerning trophic links and carbon sources by combining mercury data with stable isotope and stomach content data. Mercury also indicated that \u27Lycodes\u27 potentially belonged to a different food web than the other fishes. Results from this research demonstrated the value of elemental tracers in food web studies and generated new questions about the application and interpretation of trophic position designations

SPATIAL AND TEMPORAL PATTERNS OF ENERGY FLOW IN A SEASONALLY VARIABLE MARINE ENVIRONMENT

Food web theory has uncovered several structures, or patterns of carbon flow, that increase food web persistence. However, empirical studies focused on these structures have been largely restricted to temperate and tropical areas. In the present dissertation, I sampled the food web of Cumberland Sound, Nunavut during summer (August) and winter (April) of 2007-2009 and used stable isotopes (SI: d15N, d13C) and fatty acids (FA) to identify whether this arctic food web exhibited the following structures: 1) spatial resource coupling, 2) individual diet specialization and 3) temporal resource coupling. I first identified that the FA profile of a key arctic herbivore (Calanus hyperboreus) consistently differed between summer and winter over two years (e.g. higher 18:1n-9 in winters vs. summers), which aided in the interpretation of FAs in upper trophic levels. I then tested for the presence of spatial resource coupling in the summer food web. Based on d15N-derived trophic positions and d13C-derived % reliance on phytoplankton (vs. macroalgae), lower trophic levels fed predominantly on one of two resources and upper trophic levels used multiple resources, supporting the existence of spatial resource coupling. Following a preliminary analysis comparing Greenland shark (Somniosus microcephalus) and prey FAs, inter-tissue differences in Greenland shark 22:5n-3 among muscle, liver and plasma revealed that some individual sharks fed on consistent resources, but that the extent of individual diet specialization varied over time. Individual Greenland sharks were therefore concluded to feed as generalists, which is consistent with the finding that Cumberland Sound consumers acted as spatial resource couplers. Finally, SIs and FAs revealed that ~50% of Cumberland Sound species switched their diet between summer and winter. A literature review confirmed this temporal resource coupling by consumers on a pan-arctic scale. Overall, structures of an arctic food web agreed with those predicted by recent food web theory, such that spatial and temporal variability in resource abundance and consumer feeding behaviour are likely important for arctic food web persistence. In this context, any result of climate warming that acts to synchronize resource dynamics or remove consumer resource coupling could decrease the persistence of arctic food webs

Mental Health is not Affected by Multiple Concussions in Young Adults

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RFD-SF and Time to Peak Force for Grip Strength is not affected in College Aged Students with Multiple Concussions

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Information Processing is not Affected by Multiple Concussions in College Age Students

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Lived residencies, experiential learning and thick geographies: how artists produce knowledge(s) in the social studio

This practice-based research articulates how contemporary artists learn from their peers and others within social studio, or group, artists’ residency (SSAR), and ways in which the disruption of one’s habitus contributes to processual learning. I ask, when undergoing a durational place-based residency event, how does an individual artist’s practice shift, and how does conversation and “hanging out” work towards this shift? I conduct this examination in part by doing residency as a means to study them. My principal research aims are to better understand and determine how peer-led experiential learning in situ and over time affects the creative process and imagination inside the SSAR, and how this is situated inside the arts ecology both globally and regionally. To do so, I draw from the immersive learning approach unfolding from Black Mountain College (1933-1956) as a key democratic model in reimagining the place and possible futures of residency. A recent cadre of self-organised residency initiatives reflects horizontal knowledge exchange evidenced in this and other artist-run initiatives, underpinned by social constructivist, pragmatic and non-representational theories (Dewey, Ingold, Manning). However, the perception of art residencies as merely exotic getaways for artists and an escape from everyday preoccupations persists. To address these misperceptions, my research seeks to (1) determine what knowledges are produced and how meaning is co-constructed through various intensities of experience and polytemporality in SSAR; (2) articulate how artists in residency affect and are affected by itinerancy, building and dwelling, and construction of the public sphere; and (3) by centering the artist, assess the degree to which the fracturing of traditional artistic methods engenders a new essential art practice. My methodology evolves from Practice-as-Research and Participant Observation. Through my experiential art practice, I created four itinerant residency events with a cohort of international transdisciplinary peer artists, each 3-4 weeks in duration and making place in both urban and rural settings centred in Edinburgh (SCOT) and Minneapolis (USA). Secondly, I conducted fieldwork at established SSAR case studies in Scotland in order to investigate closely how these spaces function, resources are distributed, and geographies affect residents. This thesis examines host and resident experiences through semi-structured interviews with artists and residency administrators, documentation photography, videography, fieldnotes, binaural sound recordings on site, and reflective narrative. Outcomes of the study show how SSARs can engender a social contract of place-keeping and hospitality, and triangulate trust amongst artists, hosts, and publics; this, in turn, does affect practice and thickening of place. Furthermore, my research contribution to the field proposes the doing of SSAR can engender a new artistic research methodology in itself: the Live Residency, which can be deployed by other researchers and applied across disciplines

Automated Extraction of Pivot Topics for Sideways Expansion of Search Scope

Users benefit from mechanisms that can help them refine their queries to facilitate searching for information connected to their underlying intent. Apart from refinements to narrow the scope of a query, users can benefit from suggestions that can help them pivot their information seeking by expanding their search sideways to related topics. This disclosure describes computational techniques for automated determination of suitable topics and/or queries for helping users expand the scope of their information search by pivoting to topics related to their query. The techniques involve selecting a meta-query, performing query expansion, identifying, aggregating, and deduplicating related entities. The identified entities are clustered and ranked to enable selection of particular entities that can be shown to users as pivot topics

Effects of seasonal seston and temperature changes on lake zooplankton fatty acids

Abstract We investigated how seston fatty acids (FA) and water temperature explained seasonal variation in cladoceran and copepod FA over three years in pre-alpine, oligotrophic Lake Lunz, Austria. Using the mostly algalderived polyunsaturated FA (PUFA: arachidonic, ARA; eicosapentaenoic, EPA; docosahexaenoic acid, DHA), terrestrial FA (TFA, 22 : 0, 24 : 0), and bacterial FA (BAFA, 15 : 0, 17 : 0 and their branched homologues) as source-specific biomarkers, we show that cladocerans consistently contained more ARA and EPA and copepods more DHA than the available food (seston). None of these physiologically important PUFA were significantly related between zooplankton and seston across the entire study period but copepod DHA increased with seston DHA during the coldest months (< 8 C, based on a significant seston FA*temperature interaction). EPA, conversely, increased with decreasing water temperature in both zooplankton groups. For the nonessential FA, TFA were lower in zooplankton than in seston and not related to dietary supply or water temperature. However, cladoceran and copepod BAFA increased significantly with increasing seston BAFA and decreasing water temperature. These findings suggest that physiological regulation in response to changing water temperature had a significant impact on cladoceran and copepod EPA and the extent of dietary tracking for copepod DHA. TFA available in the seston may not have been consumed or were poorly incorporated by zooplankton, but BAFA were good indicators of available resources throughout multiple seasonal cycles. Based on our study, both FA type and water temperature impact the extent that dietary vs. nondietary processes govern cladoceran and copepod FA in oligotrophic lakes

Comparative Brain Morphology of the Greenland and Pacific Sleeper Sharks and its Functional Implications

In cartilaginous fishes, variability in the size of the brain and its major regions is often associated with primary habitat and/or specific behavior patterns, which may allow for predictions on the relative importance of different sensory modalities. The Greenland (Somniosus microcephalus) and Pacific sleeper (S. pacificus) sharks are the only non-lamnid shark species found in the Arctic and are among the longest living vertebrates ever described. Despite a presumed visual impairment caused by the regular presence of parasitic ocular lesions, coupled with the fact that locomotory muscle power is often depressed at cold temperatures, these sharks remain capable of capturing active prey, including pinnipeds. Using magnetic resonance imaging (MRI), brain organization of S. microcephalus and S. pacificus was assessed in the context of up to 117 other cartilaginous fish species, using phylogenetic comparative techniques. Notably, the region of the brain responsible for motor control (cerebellum) is small and lacking foliation, a characteristic not yet described for any other large-bodied (\u3e3 m) shark. Further, the development of the optic tectum is relatively reduced, while olfactory brain regions are among the largest of any shark species described to date, suggestive of an olfactory-mediated rather than a visually-mediated lifestyle

Seasonal increases in fish trophic niche plasticity within a flood-pulse river ecosystem (Tonle Sap Lake, Cambodia)

Species' responses to seasonal environmental variation can influence trophic interactions and food web structure within an ecosystem. However, our ability to predict how species' interactions will vary spatially and temporally in response to seasonal variation unfortunately remains inadequate within most ecosystems. Fish assemblages in the Tonle Sap Lake (TSL) of Cambodia-a dynamic flood-pulse ecosystem-were studied for five years (2010-2014) using stable isotope and Bayesian statistical approaches to explore both within-and among-species isotopic niche variation associated with seasonal flooding. Roughly 600 individual fish specimens were collected during 19 sampling events within the lake. We found that fishes within the same species tended to have a broader isotopic niche during the wet season, likely reflecting assimilation of resources from either a wider range of isotopically distinct prey items or a variety of habitats, or both. Furthermore, among-species isotopic niches tended to overlap and range more broadly during the wet season, suggesting that floodplain inundation promotes exploitation of more diverse and similar resources by different species in the fish community. Our study highlights that the flood-pulse dynamic that is typical of tropical aquatic ecosystems may be an essential element supporting freshwater fish community structure and the fish diversity that underpins the TSL food web. This flow regime is currently threatened by regional dam development, which may in turn impact the natural function and structure of the fishery food web