89 research outputs found

    Law and Peace: A Legal Framework for United Nations Peacekeeping

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    The hypothesis of this work is that international human rights law and not international humanitarian law is the legal framework that applies to United Nations (UN) peacekeeping operations in collapsed States where the peacekeepers do not become a party to an armed conflict. In order to test this hypothesis the work begins by examining what is meant by peacekeeping and charts the evolution of peacekeeping from its origins as a passive ad hoc activity to the modern highly complex operations capable of providing the foundations for the recreation of civil society. Chapter two of the work builds on the first chapter by analysing the UNâs theoretical approach to peacekeeping through its major reports. This chapter provides insight into the development of peacekeeping as a theoretical construct and then into a central tool in the UNâs attempt to implement the Charter. Chapters three and four analyse peacekeeping as practiced by the UN in operations conducted under Chapters VI and VII of the UN Charter. This analysis leads to the conclusion that as a matter of practice the UN and the State parties that have provided the troops to perform peacekeeping under UN control have acted in accordance with international human rights law and that as a result there is evidence of State practice to support an argument that as a matter of customary international law international human rights law applies as the framework for peacekeeping in collapsed States. With a clear grounding in the practice and theory of peacekeeping the work then examines the competing claims of international humanitarian law and international human rights law as the legal framework for peacekeeping operations. Suggestions are made with regard to the triggers for international humanitarian law to apply and the conclusion is drawn that the vast majority of UN operations between 1949 and 2003 were conducted beneath the threshold for the application of international humanitarian law. The final chapter of the work analyses the practical application of a human rights framework to peacekeeping and concludes that it provides a flexible and adaptive tool for the restoration of peace and the reconstruction of civil society. As a result of the analysis of UN peacekeeping theory, practice and the competing claims of international humanitarian law and international human rights law, the work concludes that international human rights law provides the framework for UN peacekeeping in collapsed States and that international humanitarian law will only apply where peacekeepers cross the threshold into armed conflict

    Split-merge cycle, fragmented collapse, and vortex disintegration in rotating Bose-Einstein condensates with attractive interactions

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    The dynamical instabilities and ensuing dynamics of singly- and doubly-quantized vortex states of Bose-Einstein condensates with attractive interactions are investigated using full 3D numerical simulations of the Gross-Pitaevskii equation. With increasing the strength of attractive interactions, a series of dynamical instabilities such as quadrupole, dipole, octupole, and monopole instabilities emerge. The most prominent instability depends on the strength of interactions, the geometry of the trapping potential, and deviations from the axisymmetry due to external perturbations. Singly-quantized vortices split into two clusters and subsequently undergo split-merge cycles in a pancake-shaped trap, whereas the split fragments immediately collapse in a spherical trap. Doubly-quantized vortices are always unstable to disintegration of the vortex core. If we suddenly change the strength of interaction to within a certain range, the vortex splits into three clusters, and one of the clusters collapses after a few split-merge cycles. The vortex split can be observed using a current experimental setup of the MIT group.Comment: 11 pages, 10 figure

    Dynamics of Dark-Bright Solitons in Cigar-Shaped Bose-Einstein Condensates

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    We explore the stability and dynamics of dark-bright solitons in two-component elongated Bose-Einstein condensates by developing effective 1D vector equations as well as solving the corresponding 3D Gross-Pitaevskii equations. A strong dependence of the oscillation frequency and of the stability of the dark-bright (DB) soliton on the atom number of its components is found. Spontaneous symmetry breaking leads to oscillatory dynamics in the transverse degrees of freedom for a large occupation of the component supporting the dark soliton. Moreover, the interactions of two DB solitons are investigated with special emphasis on the importance of their relative phases. Experimental results showcasing dark-bright soliton dynamics and collisions in a BEC consisting of two hyperfine states of 87^{87}Rb confined in an elongated optical dipole trap are presented.Comment: 4 pages, 5 figure

    Moving forward in HIV-associated cancer

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    Cancer has been linked to HIV since the earliest days of the epidemic. The unusually frequent occurrence of Kaposi sarcoma (KS) among men who have sex with men (MSM) in 1981 was a sentinel observation leading to the inclusion of KS in the first AIDS case definition.1,2 More than three decades later, major research investments have led to striking advances in understanding HIV pathogenesis, with antiretroviral therapy (ART) reducing AIDS complications and allowing HIV-infected individuals to experience life expectancy approaching that of persons without HIV

    Reply to P. de Paoli et al

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    Weare grateful for the correspondence provided by De Paoli and Carbone1 regarding our recently published Comments and Controversies piece focused on HIV-associated cancers. Their letter provides an important extension of some of the main points articulated in our article. Indeed, we wish to acknowledge our correspondents’ own excellent review also highlighting the complexity and heterogeneity of cancers occurring in the HIV-infected populatio

    From QCD lattice calculations to the equation of state of quark matter

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    We describe two-flavor QCD lattice data for the pressure at finite temperature and zero chemical potential within a quasiparticle model. Relying only on thermodynamic selfconsistency, the model is extended to nonzero chemical potential. The results agree with lattice calculations in the region of small chemical potential.Comment: 5 eps figure

    Adaptable antigen matrix platforms for peptide vaccination strategies and T cell-mediated anti-tumor immunity

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    Injection of antigenic peptides has been widely used as a vaccine strategy to boost T cell immunity. However, the poor immunogenicity of single peptides can potentially be strengthened through modification of the tertiary structure and the selection of the accompanying adjuvant. Here, we generated antigenic peptides into non-linear trimers by solid phase peptide synthesis, thereby enhancing antigen presentation by dendritic cells to CD8+ T cells in vitro and in vivo. CD8+ T cells from mice vaccinated with trimers showed an KLRG1+ effector phenotype and were able to recognize and kill antigen-expressing tumor cells ex vivo. Importantly, trimers outperformed synthetic long peptide in terms of T cell response even when equal number of epitopes were used for immunization. To improve the synthesis of trimers containing difficult peptide sequences, we developed a novel small molecule that functions as conjugation platform for synthetic long peptides. This platform, termed Antigen MAtriX (AMAX) improved yield, purity and solubility of trimers over conventional solid phase synthesis strategies. AMAX outperformed synthetic long peptides in terms of both CD8+ and CD4+ T cell responses and allowed functionalization with DC-SIGN-binding carbohydrates for in vivo dendritic cell targeting strategies, boosting T cell responses even further. Moreover, we show that ag

    Nanofabrication by magnetic focusing of supersonic beams

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    We present a new method for nanoscale atom lithography. We propose the use of a supersonic atomic beam, which provides an extremely high-brightness and cold source of fast atoms. The atoms are to be focused onto a substrate using a thin magnetic film, into which apertures with widths on the order of 100 nm have been etched. Focused spot sizes near or below 10 nm, with focal lengths on the order of 10 microns, are predicted. This scheme is applicable both to precision patterning of surfaces with metastable atomic beams and to direct deposition of material.Comment: 4 pages, 3 figure

    Deconfining Phase Transition as a Matrix Model of Renormalized Polyakov Loops

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    We discuss how to extract renormalized from bare Polyakov loops in SU(N) lattice gauge theories at nonzero temperature in four spacetime dimensions. Single loops in an irreducible representation are multiplicatively renormalized without mixing, through a renormalization constant which depends upon both representation and temperature. The values of renormalized loops in the four lowest representations of SU(3) were measured numerically on small, coarse lattices. We find that in magnitude, condensates for the sextet and octet loops are approximately the square of the triplet loop. This agrees with a large NN expansion, where factorization implies that the expectation values of loops in adjoint and higher representations are just powers of fundamental and anti-fundamental loops. For three colors, numerically the corrections to the large NN relations are greatest for the sextet loop, ≤25\leq 25%; these represent corrections of ∼1/N\sim 1/N for N=3. The values of the renormalized triplet loop can be described by an SU(3) matrix model, with an effective action dominated by the triplet loop. In several ways, the deconfining phase transition for N=3 appears to be like that in the N=∞N=\infty matrix model of Gross and Witten.Comment: 24 pages, 7 figures; v2, 27 pages, 12 figures, extended discussion for clarity, results unchange
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