10,461 research outputs found
Modeling the effect of predicted sea-level rise on coastal conservation habitats using GIS
Global average temperatures have in
creased by about 0.6°C (± 0.2°C)
during the 20th century, and are project
ed to increase by 1.4 - 5.8°C by
2100 (IPCC, 2001a). The relationship
between atmospheric warming and
sea-level rise (SLR) is well understood,
and this change is predicted to lead
to SLR of up to 1m by 2100, cr
eating consequences for coastal
communities and environments
worldwide (IPCC, 2001b)
Dual-frequency GPS survey for validation of a regional DTM and for the generation of local DTM data for sea-level rise modelling in an estuarine salt marsh
Global average temperatures have risen by an average of 0.07°C per decade over the last
100 years, with a warming trend of 0.13°C per decade over the last 50 years.
Temperatures are predicted to rise by 2°C - 4.4°C by 2100 leading to global average sealevel
rise (SLR) of 2 – 6mm per year (20 – 60cms in total) up to 2100 (IPCC 2007) with
impacts for protected coastal habitats in Ireland.
Estuaries are predominantly sedimentary environments, and are characterised by shallow
coastal slope gradients, making them sensitive to even modest changes in sea-level. The
Shannon estuary is the largest river estuary in Ireland and is designated as a Special Area
of Conservation (SAC) under the EU Habitats Directive (EU 1992) providing protection
for listed habitats within it, including estuarine salt marsh.
Trends in Shannon estuary tidal data from 1877 – 2004 suggest an average upward SLR
trend of 4 - 5mm/yr over this period. A simple linear extension of this historical trend
would imply that local SLR will be in the region of 40 - 45cm by 2100. However, this
may underestimate actual SLR for the estuary by 2100, since it takes no account of
predicted climate-driven global SLR acceleration (IPCC 2007) up to 2100
Numerical analysis of suction embedded plate anchors in structured clay
As offshore energy developments move towards deeper water, moored floating production facilities are increasingly preferred to fixed structures. Anchoring systems are therefore of great interest to engineers working on deep water developments. Suction embedded plate anchors (SEPLAs) are rapidly becoming a popular solution, possessing a more accurate and predictable installation process compared to traditional alternatives. In this paper, finite element analysis has been conducted to evaluate the ultimate pullout capacity of SEPLAs in a range of post-keying configurations. Previous numerical studies of anchor pullout capacity have generally treated the soil as an elastic-perfectly plastic medium. However, the mechanical behaviour of natural clays is affected by inter-particle bonding, or structure, which cannot be accounted for using simple elasto-plastic models. Here, an advanced constitutive model formulated within the kinematic hardening framework is used to accurately predict the degradation of structure as an anchor embedded in a natural soft clay deposit is loaded to its pullout capacity. In comparison with an idealised, non-softening clay, the degradation of clay structure due to plastic strains in the soil mass results in a lower pullout capacity factor, a quantity commonly used in design, and a more complex load–displacement relationship. It can be concluded that clay structure has an important effect on the pullout behaviour of plate anchors.Peer ReviewedPostprint (author's final draft
Competition between Pressure and Gravity Confinement in Lyman-Alpha Forest Observations
A break in the distribution function of Ly clouds (at a typical
redshift of ) has been reported by Petitjean et al. (1993). This feature
is what would be expected from a transition between pressure confinement and
gravity confinement (as predicted in Charlton, Salpeter, and Hogan (1993)). The
column density at which the feature occurs has been used to determine the
external confining pressure, , which could be
due to a hot, intergalactic medium. For models that provide a good fit to the
data, the contribution of the gas in clouds to is small. The specific
shape of the distribution function at the transition (predicted by models to
have a non-monotonic slope) can serve as a diagnostic of the distribution of
dark matter around Ly forest clouds, and the present data already
eliminate certain models.Comment: 10 pages plain TeX, 2 figures available upon request, submitted to
ApJ Letters, PSU-jc-
A desire for immersion: the panorama to the Oculus Rift
The paper argues that the experience of viewing 360° historical scenes, either within the "real" environment of the panorama or contemporary "virtual" environments, arises in part from the attraction of the affecting experience. Tracing a line from ancient Greece and Rome through to contemporary technological innovations in Virtual Reality, we explore an idea that what links all of these experiences is not solely a response to social, political or historical streams but a manifestation of a pan-historical human desire for the Dionysiac.
Using texts by theorists as diverse as Nietzsche, Baudrillard, Rheingold, Gibson and Shaviro, we suggest that the impetus for viewing historical scenes within 360° environments is at least partly involved in wanting to go beyond spectatorship and intellectual curiousity, towards presence and intoxication. Attempts to tease out the ideological content of an immersive experience must be done in the context of the craving of audience members for the sensual, the sensational, the being present, and other "illegitimate" forms of impetus to view and experiences. These always already exist alongside and perhaps even before the more legitimate goals of gaining knowledge, historical perspective, education and information.
Charlton and Moar explore the idea that this desire for immersion impels us to submerge ourselves in historical scenes. Thus immersion is the link between panoramas and new panoramic experiences afforded by new technologies such as the Oculus Rift
VR and the dramatic theatre: are they fellow creatures?
This paper describes an experimental project that aims to investigate the scope of methodological and technical possibilities of using 360° videos for experiencing authored drama. In particular, it examines how a work written for the medium of theatre, with a traditional audience-drama relationship of viewer invisibility and non-participation, might translate into a viewing experience as a VR drama. The technical and dramaturgical issues arising from this are discussed. Specifically, the shared voyeuristic quality of both media is examined. Is the invisible viewer of VR drama in the invidious role of Glaucon’s iniquitous shepherd Gyges, or does the medium give invisibility a cloak of aesthetic value
No preference in female sika deer for conspecific over heterospecific male sexual calls in a mate choice context
Mating signals can be used both in contexts of species recognition and mate quality assessment. This study examines species recognition abilities in oestrous females presented with male mating calls from both conspecifics and closely related allopatric heterospecifics. Red deer and sika deer are naturally allopatric polygynous species capable of hybridization during sympatry. Male mating calls are sexually selected and differ greatly between species. Previous work indicated that most but not all oestrous red deer hinds prefer male mating calls from conspecifics over heterospecific sika deer. Using two-speaker playback experiments, we extend this examination by measuring the preference responses of oestrous sika deer hinds to these stimuli. We predicted that oestrous sika deer hinds will show little flexibility in behavioural responses and prefer conspecific calls over heterospecific calls, similar to those of red deer hinds. In contrast, sika deer hinds showed high levels of flexibility and no difference in overall preference behaviours, suggesting that vocal behaviour does not provide a solid barrier to hybridization in this species. The asymmetry in heterospecific preference responses between these species is discussed in relation to possible causation and hybridization patterns observed in free-ranging populations
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