8,988 research outputs found
Challenges to the Aarhus convention: Public participation in the energy planning process in the United Kingdom
This article examines the tension between the democratic right of public participation on specific environmental issues, guaranteed by European Law, and the degree to which it is being challenged in the UK as a consequence of recent approaches to energy infrastructure planning. Recent trends in UK government policy frameworks seem both to threaten effective public participation and challenge EU planning strategy, in particular those outlined in the Aarhus convention. The research outlined in this study involves an assessment of the changing context of planning and energy policy, in addition to recent changes in legislation formulation in the UK. The research findings, derived from an extensive interview process of elite stakeholders engaged in policy and legislation formulation in the UK and the EU provide a new categorisation system of stakeholders in energy policy that can be utilised in future research. The article concludes with a second order analysis of the interviewee data and provides solutions to increase public participation in the planning of energy infrastructure that emerge from the different perspectives
NGC 4254: An Act of Harassment Uncovered by the Arecibo Legacy Fast ALFA Survey
We present an HI map constructed from the Arecibo Legacy Fast ALFA (ALFALFA)
survey of the surroundings of the strongly asymmetric Virgo cluster Sc galaxy
NGC 4254. Noted previously for its lopsided appearance, rich interstellar
medium, and extradisk HI emission, NGC 4254 is believed to be entering the
Virgo environment for the first time and at high speed. The ALFALFA map clearly
shows a long HI tail extending ~250 kpc northward from the galaxy. Embedded as
one condensation within this HI structure is the object previously identified
as a "dark galaxy": Virgo HI21 (Davies et al. 2004). A body of evidence
including its location within and velocity with respect to the cluster and the
appearance and kinematics of its strong spiral pattern, extra-disk HI and
lengthy HI tail is consistent with a picture of "galaxy harassment" as proposed
by Moore et al. (1996a,b; 1998). The smoothly varying radial velocity field
along the tail as it emerges from NGC 4254 can be used as a timing tool, if
interpreted as resulting from the coupling of the rotation of the disk and the
collective gravitational forces associated with the harassment mechanism.Comment: accepted for publication in Ap.J.(Lett.). higher resolution figure
available at http://egg.astro.cornell.edu/alfalfa/pubs/figs/n4254_f1.ep
Tidal Effects in Clusters of Galaxies
High-redshift clusters of galaxies show an over-abundance of spirals by a
factor of 2-3, and the corresponding under-abundance of S0 galaxies, relative
to the nearby clusters. This morphological evolution can be explained by tidal
interactions with neighboring galaxies and with the hierarchically growing
cluster halo. The efficiency of tidal interactions depends on the size and
structure of the cluster, as well as on the epoch of its formation. I simulate
the formation and evolution of Virgo-type clusters in three cosmologies: a
critical density model Omega_0=1, an open model Omega_0=0.4, and a flat model
Omega_0=0.4 with a cosmological constant. The orbits of identified halos are
traced with a high temporal resolution (~10^7 yr). Halos with low relative
velocities merge only shortly after entering the cluster; after virialization
mergers are suppressed. The dynamical evolution of galaxies is determined by
the tidal field along their trajectories. The maxima of the tidal force do not
always correspond to closest approach to the cluster center. They are produced
to a large extent by the local density structures, such as the massive galaxies
and the unvirialized remnants of infalling groups of galaxies. Collisions of
galaxies are intensified by the substructure, with about 10 encounters within
10 kpc per galaxy in the Hubble time. These very close encounters add an
important amount (10-50%) of the total heating rate. The integrated effect of
tidal interactions is insufficient to transform a spiral galaxy into an
elliptical, but can produce an S0 galaxy. Overall, tidal heating is stronger in
the low Omega_0 clusters
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