128 research outputs found
Picturing the nation : The Celtic periphery as discursive other in the archaeological displays of the museum of Scotland
Using the archaeological displays at the Museum of Scotland in Edinburgh, this paper examines the exhibition as a site of identity creation through the negotiations between categories of same and Other. Through an analysis of the poetics of display, the paper argues that the exhibition constructs a particular relationship between the Celtic Fringe and Scottish National identity that draws upon the historical discourses of the Highlands and Islands of Scotland as a place and a time \u27apart\u27. This will be shown to have implications for the display of archaeological material in museums but also for contemporary understandings of Scottish National identity. <br /
Ethos of Ambiguity: Artist Teachers and the Transparency Exclusion Paradox
Addressing changes in conditions for practitioners that can be related to education policy in England and Wales since 2010, this article presents issues faced by teachers of art and design and theorises responses in practice. The current insistence on transparency in education emerges through policy that audits performativity, in a limiting skills bank. Practitioners in Art and Design are particularly affected by what I term âthe transparency-exclusion paradoxâ, as they battle to maintain the subject area and are âotheredâ by the EBacc and Progress 8. I will discuss an emergent âethos of ambiguityâ among artist-teachers and contemporary artists, with a theoretical basis informed by Beauvoir and Foucault. Empirical data from research participants will be evidenced, to explore strategies of response in inclusive social practice. This article adds to literature that considers the effects of policy in implementation and it contributes to research on creative expressions of ambiguity in the arts
A fluorescence approach to investigate repartitioning of coalescing agents in acrylic polymer emulsions
Repartitioning of co-solvents between particles of latex emulsions was investigated by means of a fluorescence method based on the detection of the amount of co-solvent via the solvatochromic shift of the emission maximum of a fluorescent probe, copolymerized at a low concentration. Complete repartitioning of co-solvents between particles of latex materials with a low Tg (ca. 25 °C) occurred within minutes. For a hydrophilic latex with a Tg of 68 °C, equilibration was achieved within an hour. Repartitioning was faster for more hydrophobic co-solvents. For a hydrophobic latex of similar Tg, co-solvent repartitioning took place on the same time scale, but complete equilibration was not reached. Possibly, there is an additional slow component in the repartitioning, or the prolonged presence of co-solvent causes a structural change in the latex particles that affects the outcome of the experiment
A systematic autopsy survey of human infant bridging veins
In the first years of life, subdural haemorrhage (SDH) within the cranial cavity can occur through accidental and non-accidental mechanisms as well as from birth-related injury. This type of bleeding is the most common finding in victims of abusive head trauma (AHT). Historically, the most frequent cause of SDHs in infancy is suggested to be traumatic damage to bridging veins traversing from the brain to the dural membrane. However, several alternative hypotheses have been suggested for the cause and origin of subdural bleeding. It has also been suggested by some that bridging veins are too large to rupture through the forces associated with AHT. To date, there have been no systematic anatomical studies on infant bridging veins. During 43 neonatal, infant and young child post-mortem examinations, we have mapped the locations and numbers of bridging veins onto a 3D model of the surface of a representative infant brain. We have also recorded the in situ diameter of 79 bridging veins from two neonatal, one infant and two young children at post-mortem examination. Large numbers of veins, both distant from and directly entering the dural venous sinuses, were discovered travelling between the brain and dural membrane, with the mean number of veins per brain being 54.1 and the largest number recorded as 94. The mean diameter of the bridging veins was 0.93Â mm, with measurements ranging from 0.05 to 3.07Â mm. These data demonstrate that some veins are extremely small and subjectively, and they appear to be delicate. Characterisation of infant bridging veins will contribute to the current understanding of potential vascular sources of subdural bleeding and could also be used to further develop computational models of infant head injury
Global assessment of marine plastic exposure risk for oceanic birds
Plastic pollution is distributed patchily around the world's oceans. Likewise, marine organisms that are vulnerable to plastic ingestion or entanglement have uneven distributions. Understanding where wildlife encounters plastic is crucial for targeting research and mitigation. Oceanic seabirds, particularly petrels, frequently ingest plastic, are highly threatened, and cover vast distances during foraging and migration. However, the spatial overlap between petrels and plastics is poorly understood. Here we combine marine plastic density estimates with individual movement data for 7137 birds of 77 petrel species to estimate relative exposure risk. We identify high exposure risk areas in the Mediterranean and Black seas, and the northeast Pacific, northwest Pacific, South Atlantic and southwest Indian oceans. Plastic exposure risk varies greatly among species and populations, and between breeding and non-breeding seasons. Exposure risk is disproportionately high for Threatened species. Outside the Mediterranean and Black seas, exposure risk is highest in the high seas and Exclusive Economic Zones (EEZs) of the USA, Japan, and the UK. Birds generally had higher plastic exposure risk outside the EEZ of the country where they breed. We identify conservation and research priorities, and highlight that international collaboration is key to addressing the impacts of marine plastic on wide-ranging species
Infrasound as a cue for seabird navigation
Seabirds are amongst the most mobile of all animal species and spend large amounts of their lives at sea. They cross vast areas of ocean that appear superficially featureless, and our understanding of the mechanisms that they use for navigation remains incomplete, especially in terms of available cues. In particular, several large-scale navigational tasks, such as homing across thousands of kilometers to breeding sites, are not fully explained by visual, olfactory or magnetic stimuli. Low-frequency inaudible sound, i.e., infrasound, is ubiquitous in the marine environment. The spatio-temporal consistency of some components of the infrasonic wavefield, and the sensitivity of certain bird species to infrasonic stimuli, suggests that infrasound may provide additional cues for seabirds to navigate, but this remains untested. Here, we propose a framework to explore the importance of infrasound for navigation. We present key concepts regarding the physics of infrasound and review the physiological mechanisms through which infrasound may be detected and used. Next, we propose three hypotheses detailing how seabirds could use information provided by different infrasound sources for navigation as an acoustic beacon, landmark, or gradient. Finally, we reflect on strengths and limitations of our proposed hypotheses, and discuss several directions for future work. In particular, we suggest that hypotheses may be best tested by combining conceptual models of navigation with empirical data on seabird movements and in-situ infrasound measurements
Some technique-dependent patterns of collateral flow during cerebral angiography
During selective transfemoral catheter cerebral angiography, anastomoses between external carotid branches and the vertebral artery, between the vertebral and deep or ascending cervical arteries, and between the middle meningeal and ophthalmic arteries can be demonstrated fairly frequently in patients with no known vascular abnormalities. One can occasionally show bidirectional filling of these anastomoses depending on the vessel injected. Visualization of these anastomoses occurs to a variable degree and is sometimes entirely technique-dependent, reflecting a transient increase in the intraluminal pressure during the injection of contrast medium.-Thus, demonstration of extracranial collateral arterial flow during cerebral angiography should not necessarily be interpreted as an abnormal phenomenon, such as may be seen with arterial occlusive disease, vascular malformation, or a very vascular tumor. Au cours de l'angiographie cĂ©rĂ©brale parcathĂ©tĂ©rismes sĂ©lectifs par voie fĂ©morale, peuvent apparaĂźtre des anastomoses entre des branches carotidiennes externes et l'artĂšre vertĂ©brale, entre l'artĂšre vertĂ©brale et les artĂšres cĂ©rĂ©brales profondes ou ascendantes et entre l'artĂšre mĂ©ningĂ©e moyenne et l'artĂšre ophtalmique. Occasionnellement, on peut mettre en Ă©vidence un remplissage bidirectionnel de ces anastomoses, en rapport avec le vaisseau injectĂ©. La visualisation de ces anastomoses se produit de facon variable dĂ©pend parfois entiĂšrement de la technique, reflĂ©tant une augmentation transitoire de la pression dans l'artĂšre durant l'injection du produit de contraste. Par consĂ©quent, l'observation d'une circulation artĂ©rielle collatĂ©rale extracrĂąnienne pendant une angiographie cĂ©rĂ©brale ne reprĂ©sente pas nĂ©cĂ©ssairement un phĂ©nomĂšne anormal tel qu'on le rencontre dans les troubles artĂ©riels occlusifs, dans les malformations vasculaires et dans les tumeurs vascularisĂ©es. WĂ€hrend der selektiven transfemoralen Katheter-Angiographie können sich Anastomosen zwischen Externa-GefĂ€Ăen und der A. vertebralis, zwischen der A. vertebralis und tiefen oder aufsteigenden cervicalen Arterien und zwischen der A. meningica media und der A. ophthalmica darstellen. Diese Befunde finden sich auch bei Patienten, bei denen keine Gef:aĂanomalien vorliegen. Gelegentlich wird ein bidirektionaler KontrastmitteldurchfluĂ durch diese Anastomosen nachgewiesen, dabei ist die KontrastmittelfĂŒllung von der Lokalisation der Kontrastmittelinjektion abhĂ€ngig. Es zeigt sich also, daĂ diese unterschiedlichen Durchströmungen technisch bedingt werden können und nicht immer als abnormales PhĂ€nomen gedeutet werden können.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/46671/1/234_2004_Article_BF00341594.pd
Global assessment of marine plastic exposure risk for oceanic birds
Plastic pollution is distributed patchily around the worldâs oceans. Likewise, marine organisms that are vulnerable to plastic ingestion or entanglement have uneven distributions. Understanding where wildlife encounters plastic is crucial for targeting research and mitigation. Oceanic seabirds, particularly petrels, frequently ingest plastic, are highly threatened, and cover vast distances during foraging and migration. However, the spatial overlap between petrels and plastics is poorly understood. Here we combine marine plastic density estimates with individual movement data for 7137 birds of 77 petrel species to estimate relative exposure risk. We identify high exposure risk areas in the Mediterranean and Black seas, and the northeast Pacific, northwest Pacific, South Atlantic and southwest Indian oceans. Plastic exposure risk varies greatly among species and populations, and between breeding and non-breeding seasons. Exposure risk is disproportionately high for Threatened species. Outside the Mediterranean and Black seas, exposure risk is highest in the high seas and Exclusive Economic Zones (EEZs) of the USA, Japan, and the UK. Birds generally had higher plastic exposure risk outside the EEZ of the country where they breed. We identify conservation and research priorities, and highlight that international collaboration is key to addressing the impacts of marine plastic on wide-ranging species
Effects of body size, sex, parental care and moult strategies on auk diving behaviour outside the breeding season
Information on seabird foraging behaviour outside the breeding season is currently limited. This knowledge gap is critical as this period is energetically demanding due to postâfledging parental care, feather moult and changing environmental conditions. Based on speciesâ body size, postâfledging parental strategy and primary moult schedule we tested predictions for key aspects of foraging behaviour (Maximum Dive Depth (MDD), Daily Time Submerged (DTS) and Diurnal Dive Activity (DDA)) using dive depth data collected from three seabird species (common guillemot Uria aalge, razorbill Alca torda and Atlantic puffin Fratercula arctica) from the end of the breeding season (July) to midâwinter (January). We found partial support for predictions associated with body size; guillemots had greater MDD than razorbills but MDD did not differ between razorbills and puffins, despite the former being 35% heavier. In accordance with sexual monomorphism in all three species, MDD did not differ overall between the sexes. However, in guillemots and razorbills there were sexâspecific differences, such that male guillemots made deeper dives than females, and males of both species had higher DTS. In contrast, there were no marked sex differences in dive behaviour of puffins in July and August in accordance with their lack of postâfledging parental care and variable moult schedule. We found support for the prediction that diving effort would be greater in midâwinter compared to the period after the breeding season. Despite reduced daylight in midâwinter, this increase in DTS occurred predominantly during the day and only guillemots appeared to dive nocturnally to any great extent. In comparison to diving behaviour of these species recorded during the breeding season, MDD was shallower and DTS was greater during the nonâbreeding period. Such differences in diving behaviour during the postâbreeding period are relevant when identifying potential energetic bottlenecks, known to be key drivers of seabird population dynamics
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