1,176 research outputs found
Meeting Competition: Why it is not an Abuse under Article 82. Research Papers in Law, 3/2004.
Introduction. Meeting competition occurs when an undertaking lowers its prices in response to the
entry of a competitor. Despite accepting that meeting competition can be compatible
with Article 82, the Commission2 and the Court of justice3 have repeatedly condemned the practice due to the modalities of implementation or âparticular circumstancesâ.4 However, existing precedent on the subject remains obscurely
reasoned and contradictory, such that it is at the present time impossible to give clear advice to undertakings on the circumstances in which meeting competition is
compatible with Article 82.
Not only is such legal uncertainty in itself damaging but, in so far as it discourages meeting competition, it appears to us to be harmful to competition. As concerns the
latter point, it will be seen that some of the most powerful arguments against prohibiting meeting competition are based on the counterproductive nature of the remedies.
The present article does not, however, aim to propose a simple solution to distinguish abusive and non-abusive meeting competition.5 Nor does the article aim to give a comprehensive overview of the existing case law in this area.6 Instead, it takes a more economic approach and aims to lay out in a (brief but) systematic fashion the
competitive concerns that might potentially be raised by the practice of meeting competition and in doing so to try to identify the main flaws in the Court and
Commissionâs approach
The Effect of an Outdoor Experience on Sixth Grade Students\u27 Cognitive Understanding of Ecological Concepts
This study was an investigation of the impact an exploratory field trip experience had on sixth grade students\u27 cognitive understanding of specific ecological concepts being taught by their respective instructor. The purpose of this study was to analyze the change in the cognitive level of students\u27 classroom dialogue before and after being exposed to an exploratory field trip experience. Further, this study was to verify whether a significant change in the students\u27 cognitive understanding of the ecological concepts had occurred as a result of a specific series of multi-sensory encounters in the out-of-doors
Subglacial-discharge plumes drive widespread subsurface warming in northwest Greenlandâs fjords
This work was supported by the UK Natural Environment Research Council (Grants NE/W00531X/1 and NE/T011920/1).Greenlandâs glacial fjords modulate the exchange between the ice sheet and ocean. Subglacial-discharge-driven plumes adjacent to glaciers may exert an important influence on fjord water properties, submarine glacier melting and the export of glacially-modified waters to the shelf. Here we use a numerical plume model in conjunction with observations from proximal to 14 glaciers in northwest Greenland to assess the impact of these plumes on near-glacier water properties. We find that in late summer, waters emanating from glacial plumes often make up > 50 % of the fjord water composition at intermediate depths. These plume waters are comprised largely of upwelled Atlantic Water, warming the near-glacier water profile and likely increasing submarine melting. Our findings demonstrate the key role played by plumes in driving water modification in Greenlandâs fjords, and the potential for simple models to capture these impacts across a range of settings.Publisher PDFPeer reviewe
Modelling submarine melting at tidewater glaciers in Greenland
The recent thinning, acceleration and retreat of tidewater glaciers around Greenland
suggests that these systems are highly sensitive to a change in climate. Tidewater
glacier dynamics have already had a significant impact on global sea level, and, given
projected future climate warming, will likely continue to do so over the coming century.
Understanding of the processes connecting climatic change to tidewater glacier response
is, however, at an early stage. Current leading thinking links tidewater glacier change
to ocean warming by submarine melting of glacier calving fronts, yet the process of
submarine melting remains poorly understood. This thesis combines modelling and
field data to investigate submarine melting at tidewater glaciers, ultimately seeking to
constrain the sensitivity of the Greenland Ice Sheet to climate change.
Submarine melting is thought to be enhanced where subglacial runoff enters the ocean
and drives energetic ice-marginal plumes. In this thesis, two contrasting models are used
to examine the dynamics of these plumes; the Massachusetts Institute of Technology
general circulation model (MITgcm) and the simpler buoyant plume theory (BPT).
The first result of this thesis, obtained with the MITgcm, is that the spatial distribution
of subglacial runoff at the grounding line of a tidewater glacier is a key control on
the rate and spatial distribution of submarine melting. Focussed subglacial runoff
induces rapid but localised melting, while diffuse runoff induces slower but spatially
homogeneous melting. Furthermore, for the same subglacial runoff, total ablation by
submarine melting from diffuse runoff exceeds that from focussed runoff by at least a
factor of five. BPT is then used to examine the relationship between plume-induced submarine
melting and key physical parameters, such as plume geometry, fjord stratification, and
the magnitude of subglacial runoff. It is shown that submarine melt rate is proportional
to the magnitude of subglacial runoff raised to the exponent of 1/3, regardless of
plume geometry, provided runoff lies below a critical threshold and the fjord is weakly
stratified. Above the runoff threshold and for strongly stratified fjords, the exponent
respectively decreases and increases. The obtained relationships are combined into a
single parameterisation thereby providing a useful first-order estimate of submarine
melt rate with potential for incorporation into predictive ice flow models.
Having investigated many of the factors affecting submarine melt rate, this thesis turns
to the effect of melting on tidewater glacier dynamics and calving processes. Specifically,
feedbacks between submarine melting and calving front shape are evaluated by coupling
BPT to a dynamic ice-ocean boundary which evolves according to modelled submarine
melt rates. In agreement with observations, the model shows calving fronts becoming
undercut by submarine melting, but hints at a critical role for subglacial channels in
this process. The total ablation by submarine melting increases with the degree of
undercutting due to increased ice-ocean surface area. It is suggested that the relative
pace of undercutting versus ice velocity may define the dominant calving style at a
tidewater glacier.
Finally, comparison of plumes modelled in both MITgcm and BPT with those observed
at Kangiata Nunata Sermia (KNS), a large tidewater glacier in south-west Greenland,
suggests that subglacial runoff at KNS is often diffuse in nature. In addition to
the above implications for submarine melting, diffuse drainage may enhance basal
sliding during warmer summers, thereby providing a potential link between increasing
atmospheric temperature and tidewater glacier acceleration which does not invoke the
role of the ocean.
This thesis provides a comprehensive investigation and quantification of the factors
affecting submarine melting at tidewater glaciers, a complex process that is believed
to be one of the key influences on the current and future stability of the Greenland Ice Sheet. Based on the magnitude of modelled melt rates, and their effect on calving front
shape, the process of submarine melting is a likely driver of retreat at slower-flowing
tidewater glaciers in Greenland. For melting to influence the largest and fastest-flowing
glaciers requires invoking a sensitive coupling between melting and calving which is as
yet obscure. It should however be noted that modelled melt rates depend critically on
parameters which are poorly constrained. The results and parameterisations developed
in this thesis should now be taken forward through testing against field observations
- which are currently rare - and, from a modelling perspective, coupling with ice flow
models to provide a more complete picture of the interaction of the Greenland Ice Sheet
with the ocean
Local forcing mechanisms challenge parameterizations of ocean thermal forcing for Greenland tidewater glaciers
Frontal ablation has caused 32â%â66â% of Greenland Ice Sheet mass loss since 1972, and despite its importance in driving terminus change, ocean thermal forcing remains crudely incorporated into large-scale ice sheet models. In Greenland, local fjord-scale processes modify the magnitude of thermal forcing at the iceâocean boundary but are too small scale to be resolved in current global climate models. For example, simulations used in the Ice Sheet Intercomparison Project for CMIP6 (ISMIP6) to predict future ice sheet change rely on the extrapolation of regional ocean water properties into fjords to drive terminus ablation. However, the accuracy of this approach has not previously been tested due to the scarcity of observations in Greenland fjords, as well as the inability of fjord-scale models to realistically incorporate icebergs. By employing the recently developed IceBerg package within the Massachusetts Institute of Technology general circulation model (MITgcm), we here evaluate the ability of ocean thermal forcing parameterizations to predict thermal forcing at tidewater glacier termini. This is accomplished through sensitivity experiments using a set of idealized Greenland fjords, each forced with equivalent ocean boundary conditions but with varying tidal amplitudes, subglacial discharge, iceberg coverage, and bathymetry. Our results indicate that the bathymetric obstruction of external water is the primary control on near-glacier thermal forcing, followed by iceberg submarine melting. Despite identical ocean boundary conditions, we find that the simulated fjord processes can modify grounding line thermal forcing by as much as 3â°C, the magnitude of which is largely controlled by the relative depth of bathymetric sills to the Polar WaterâAtlantic Water thermocline. However, using a common adjustment for fjord bathymetry we can still predict grounding line thermal forcing within 0.2â°C in our simulations. Finally, we introduce new parameterizations that additionally account for iceberg-driven cooling that can accurately predict interior fjord thermal forcing profiles both in iceberg-laden simulations and in observations from Kangiata Sullua (Ilulissat Icefjord)
Modeling the impact of glacial runoff on fjord circulation and submarine melt rate using a new subgrid-scale parameterization for glacial plumes
This work was funded by NERC grant NE/K014609/1 to Peter Nienow and Andrew Sole.The injection at depth of ice sheet runoff into fjords may be an important control on the frontal melt rate of tidewater glaciers. Here we develop a new parameterization for ice marginal plumes within the Massachusetts Institute of Technology General Circulation Model (MITgcm), allowing three-dimensional simulation of large (500 km2) glacial fjords on annual (or longer) time scales. We find that for an idealized fjord (without shelf-driven circulation), subglacial runoff produces a thin, strong, and warm down-fjord current in the upper part of the water column, balanced by a thick and slow up-fjord current at greater depth. Although submarine melt rates increase with runoff due to higher melt rates where the plume is in contact with the ice front, we find that annual submarine melt rate across the ice front is relatively insensitive to variability in annual runoff. Better knowledge of the spatial distribution of runoff, controls on melt rate in those areas not directly in contact with plumes, and feedback mechanisms linking submarine melting and iceberg calving are necessary to more fully understand the sensitivity of glacier mass balance to runoff-driven fjord circulation.Publisher PDFPeer reviewe
Home education for children with additional learning needs â a better choice or the only option?
This paper presents findings from a study undertaken in Wales on the safeguarding of children educated at home. Findings revealed that just under a third of home educators had children with additional learning needs who were removed from school due to what parents reported as negative experiences. These experiences included the suitability of a school system based upon assessment and attainment for children with additional learning needs and a failure to provide adequate support. The decision to home educate was not taken lightly, with parents persevering in attempts to make school work for their children. Similar issues are identified in recent media coverage in England and Wales which has suggested that rises in home education may be due to parents âoff-rollingâ their children because they feel forced out of schools that are unable or unwilling to promote inclusive practices. Findings showed that it was not school-based education that was rejected intrinsically, but rather the extent to which schools could meet their childâs needs. In the advent of the Additional Learning Needs and Education Tribunal (Wales) Act 2018, these findings suggest that a more nuanced understanding of education is required where home education, either full-time or combined with school attendance, may be in the best interests of the child
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