4,555 research outputs found
A geographical study of the united nations peacekeeping force in Cyprus, 1964 - 1984
The main aim of this study is to examine the role of the United Nations Peacekeeping Force in Cyprus in relation to fundamental changes to the human and political geography of the island. The political background to these changes is given some analysis but the major focus of the study is on the spatial aspects of intercommunal conflict, and the problems created for civilian life by artificial ethnic barriers, barbed wire- fences, sentry-posts, roadblocks, and other physical lines symbolizing the separation of the Greek and Turkish Cypriots, After a brief description of the situation prior to Independence, the centrifugal forces dividing the two communities and resulting in the formation of Turkish Cypriot enclaves are discussed. In the light of these major changes U.N.F.I.CYP. had to cope with many complicated practical difficulties on the ground relating to the separate de facto territorial control of certain parts of the Republic of Cyprus by the Turkish Cypriots. This study stresses the economic and humanitarian duties of what is basically a military peacekeeping force. In carrying out these duties there are many linkages between the non-military tasks of U.N.P.I.CYP. and the human geography of the island. Finally, the period since the forming of the de facto partition line between the two communities is considered in detail, and particular attention is given to U.N.F.I.CYP.'s activities between the two Forward Defence Lines of the National Guard and Turkish Array, i.e. in the U.N.- controlled Buffer Zone. The study then attempts to draw some conclusions regarding the likely future role of U.N.F.I.CYP., and to highlight the problems posed by the political deadlock between the two communities. There is also a short conclusion on the geography of peacekeeping, which is based entirely on this detailed case study
Combinatorial Games with a Pass: A dynamical systems approach
By treating combinatorial games as dynamical systems, we are able to address
a longstanding open question in combinatorial game theory, namely, how the
introduction of a "pass" move into a game affects its behavior. We consider two
well known combinatorial games, 3-pile Nim and 3-row Chomp. In the case of Nim,
we observe that the introduction of the pass dramatically alters the game's
underlying structure, rendering it considerably more complex, while for Chomp,
the pass move is found to have relatively minimal impact. We show how these
results can be understood by recasting these games as dynamical systems
describable by dynamical recursion relations. From these recursion relations we
are able to identify underlying structural connections between these "games
with passes" and a recently introduced class of "generic (perturbed) games."
This connection, together with a (non-rigorous) numerical stability analysis,
allows one to understand and predict the effect of a pass on a game.Comment: 39 pages, 13 figures, published versio
The ISO LWS high resolution spectral survey towards Sagittarius B2
A full spectral survey was carried out towards the Giant Molecular Cloud
complex, Sagittarius B2 (Sgr B2), using the ISO Long Wavelength Spectrometer
Fabry-Perot mode. This provided complete wavelength coverage in the range
47-196 um (6.38-1.53 THz) with a spectral resolution of 30-40 km/s. This is an
unique dataset covering wavelengths inaccessible from the ground. It is an
extremely important region of the spectrum as it contains both the peak of the
thermal emission from dust, and crucial spectral lines of key atomic (OI, CII,
OIII, NII and NIII) and molecular species (NH3, NH2, NH, H2O, OH, H3O+, CH,
CH2, C3, HF and H2D+). In total, 95 spectral lines have been identified and 11
features with absorption depth greater than 3 sigma remain unassigned. Most of
the molecular lines are seen in absorption against the strong continuum,
whereas the atomic and ionic lines appear in emission (except for absorption in
the OI 63 um and CII 158 um lines). Sgr B2 is located close to the Galactic
Centre and so many of the features also show a broad absorption profile due to
material located along the line of sight. A full description of the survey
dataset is given with an overview of each detected species and final line lists
for both assigned and unassigned features.Comment: Accepted for publication in MNRA
A Brief History of Trans-Neptunian Space
The Edgeworth-Kuiper belt encodes the dynamical history of the outer solar
system. Kuiper belt objects (KBOs) bear witness to coagulation physics, the
evolution of planetary orbits, and external perturbations from the solar
neighborhood. We critically review the present-day belt's observed properties
and the theories designed to explain them. Theories are organized according to
a possible time-line of events. In chronological order, epochs described
include (1) coagulation of KBOs in a dynamically cold disk, (2) formation of
binary KBOs by fragmentary collisions and gravitational captures, (3) stirring
of KBOs by Neptune-mass planets (``oligarchs''), (4) eviction of excess
oligarchs, (5) continued stirring of KBOs by remaining planets whose orbits
circularize by dynamical friction, (6) planetary migration and capture of
Resonant KBOs, (7) creation of the inner Oort cloud by passing stars in an open
stellar cluster, and (8) collisional comminution of the smallest KBOs. Recent
work underscores how small, collisional, primordial planetesimals having low
velocity dispersion permit the rapid assembly of ~5 Neptune-mass oligarchs at
distances of 15-25 AU. We explore the consequences of such a picture. We
propose that Neptune-mass planets whose orbits cross into the Kuiper belt for
up to ~20 Myr help generate the high-perihelion members of the hot Classical
disk and Scattered belt. By contrast, raising perihelia by sweeping secular
resonances during Neptune's migration might fill these reservoirs too
inefficiently when account is made of how little primordial mass might reside
in bodies having sizes of order 100 km. These and other frontier issues in
trans-Neptunian space are discussed quantitatively.Comment: Final proofed version for Protostars and Planets V; some numbers
adjusted by factors of 2; references update
Assessing the number of users who are excluded by domestic heating controls
This is the pre-print version of the Article. This Article is also referred to as: "Assessing the 'Design Exclusion' of Heating Controls at a Low-Cost, Low-Carbon Housing Development". - Copyright @ 2011 Taylor & FrancisSpace heating accounts for almost 60% of the energy delivered to housing which in turn accounts for nearly 27% of the total UK's carbon emissions. This study was conducted to investigate the influence of heating control design on the degree of ‘user exclusion’. This was calculated using the Design Exclusion Calculator, developed by the Engineering Design Centre at the University of Cambridge. To elucidate the capability requirements of the system, a detailed hierarchical task analysis was produced, due to the complexity of the overall task. The Exclusion Calculation found that the current design placed excessive demands upon the capabilities of at least 9.5% of the UK population over 16 years old, particularly in terms of ‘vision’, ‘thinking’ and ‘dexterity’ requirements. This increased to 20.7% for users over 60 years old. The method does not account for the level of numeracy and literacy and so the true exclusion may be higher. Usability testing was conducted to help validate the results which indicated that 66% of users at a low-carbon housing development could not programme their controls as desired. Therefore, more detailed analysis of the cognitive demands placed upon the users is required to understand where problems within the programming process occur. Further research focusing on this cognitive interaction will work towards a solution that may allow users to behave easily in a more sustainable manner
Spontaneous Polarisation Build up in a Room Temperature Polariton Laser
We observe the build up of strong (~50%) spontaneous vector polarisation in
emission from a GaN-based polariton laser excited by short optical pulses at
room temperature. The Stokes vector of emitted light changes its orientation
randomly from one excitation pulse to another, so that the time-integrated
polarisation remains zero. This behaviour is completely different to any
previous laser. We interpret this observation in terms of the spontaneous
symmetry breaking in a Bose-Einstein condensate of exciton-polaritons
Methane and Nitrogen Abundances On Pluto and Eris
We present spectra of Eris from the MMT 6.5 meter telescope and Red Channel
Spectrograph (5700-9800 angstroms; 5 angstroms per pix) on Mt. Hopkins, AZ, and
of Pluto from the Steward Observatory 2.3 meter telescope and Boller and
Chivens spectrograph (7100-9400 angstroms; 2 angstroms per pix) on Kitt Peak,
AZ. In addition, we present laboratory transmission spectra of methane-nitrogen
and methane-argon ice mixtures. By anchoring our analysis in methane and
nitrogen solubilities in one another as expressed in the phase diagram of
Prokhvatilov and Yantsevich (1983), and comparing methane bands in our Eris and
Pluto spectra and methane bands in our laboratory spectra of methane and
nitrogen ice mixtures, we find Eris' bulk methane and nitrogen abundances are
about 10% and about 90%, and Pluto's bulk methane and nitrogen abundances are
about 3% and about 97%. Such abundances for Pluto are consistent with values
reported in the literature. It appears that the bulk volatile composition of
Eris is similar to the bulk volatile composition of Pluto. Both objects appear
to be dominated by nitrogen ice. Our analysis also suggests, unlike previous
work reported in the literature, that the methane and nitrogen stoichiometry is
constant with depth into the surface of Eris. Finally, we point out that our
Eris spectrum is also consistent with a laboratory ice mixture consisting of
40% methane and 60% argon. Although we cannot rule out an argon rich surface,
it seems more likely that nitrogen is the dominant species on Eris because the
nitrogen ice 2.15 micron band is seen in spectra of Pluto and Triton.Comment: The manuscript has 44 pages, 15 figures, and four tables. It will
appear in the Astrophysical Journa
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