10,581 research outputs found

    Marriage Without A Courtship

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    A geographical study of the united nations peacekeeping force in Cyprus, 1964 - 1984

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    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

    Fundamental optical and magneto-optical constants of Co/Pt and CoNi/Pt multilayered films

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    A study has been made of the optical and magneto-optical properties of several Co/Pt and CoNi/Pt multilayered films that were fabricated by magnetron sputter deposition. Spectroscopic rotating analyzer ellipsometry and Kerr polarimetry were carried out to determine the fundamental optical and magneto-optical constants over the spectral range 320¿860 nm. The constants determined were the complex refractive index and the first-order magneto-optic Voigt parameter. A total of seven films were examined and excellent reproducibility was observed in the measured material constants. These have been used to discuss the spectral dependence of the figure-of-merit, for each material, associated with the detection of the polar Kerr effect

    The Spectrum of Pluto, 0.40 - 0.93 μ\mum I. Secular and longitudinal distribution of ices and complex organics

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    Context. During the last 30 years the surface of Pluto has been characterized, and its variability has been monitored, through continuous near-infrared spectroscopic observations. But in the visible range only few data are available. Aims. The aim of this work is to define the Pluto's relative reflectance in the visible range to characterize the different components of its surface, and to provide ground based observations in support of the New Horizons mission. Methods. We observed Pluto on six nights between May and July 2014, with the imager/spectrograph ACAM at the William Herschel Telescope (La Palma, Spain). The six spectra obtained cover a whole rotation of Pluto (Prot = 6.4 days). For all the spectra we computed the spectral slope and the depth of the absorption bands of methane ice between 0.62 and 0.90 μ\mum. To search for shifts of the center of the methane bands, associated with dilution of CH4 in N2, we compared the bands with reflectances of pure methane ice. Results. All the new spectra show the methane ice absorption bands between 0.62 and 0.90 μ\mum. The computation of the depth of the band at 0.62 μ\mum in the new spectra of Pluto, and in the spectra of Makemake and Eris from the literature, allowed us to estimate the Lambert coefficient at this wavelength, at a temperature of 30 K and 40 K, never measured before. All the detected bands are blue shifted, with minimum shifts in correspondence with the regions where the abundance of methane is higher. This could be indicative of a dilution of CH4:N2 more saturated in CH4. The longitudinal and secular variations of the parameters measured in the spectra are in accordance with results previously reported in the literature and with the distribution of the dark and bright material that show the Pluto's albedo maps from New Horizons.Comment: This manuscript may change and improve during the reviewing process. The data reduction and calibration is reliable and has been checked independently using different reduction approaches. The data will be made publicily available when the paper is accepted. If you need them before, please, contact the autho

    The structure of human CD23 and its interactions with IgE and CD21

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    The low-affinity immunoglobulin E (IgE) receptor, CD23 (FcɛRII), binds both IgE and CD21 and, through these interactions, regulates the synthesis of IgE, the antibody isotype that mediates the allergic response. We have determined the three-dimensional structure of the C-type lectin domain of CD23 in solution by nuclear magnetic resonance spectroscopy. An analysis of concentration-dependent chemical shift perturbations have allowed us to identify the residues engaged in self-association to the trimeric state, whereas ligand-induced changes have defined the binding sites for IgE and CD21. The results further reveal that CD23 can bind both ligands simultaneously. Despite the C-type lectin domain structure, none of the interactions require calcium. We also find that IgE and CD23 can interact to form high molecular mass multimeric complexes. The interactions that we have described provide a solution to the paradox that CD23 is involved in both up- and down-regulation of IgE and provide a structural basis for the development of inhibitors of allergic disease

    Combinatorial Games with a Pass: A dynamical systems approach

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    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
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