11,546 research outputs found

    Social and governance dimensions of climate change : implications for policy

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    This paper addresses two vital concerns in the debate on adaptation to climate change. First, how can countries prepare to manage the impact of climate-change induced natural disasters? Second, how can countries ensure that they have the governmental institutions required to manage the phenomenal challenge of adaptation to climate change? A range of economic and institutional measures are tested for their potential effects on natural disaster resilience and the quality of environmental governance. The findings suggest an important role is played by social and political institutions in determining the ability of countries to adapt to climate change and respond to natural disasters, in particular in the degree to which countries have succeeded in gender empowerment and the development of a robust civil society and nonprofit sector. As the climate change challenge moves from that of"proving the facts"to that of"implementing change,"the authors suggest that international policymakers, donors, and activists must increasingly focus on building domestic policy environments that are conducive to the delivery of more effective environmental legislation, for example through implementation of gender quotas and provision of support to civil society groups.Environmental Economics&Policies,Population Policies,Natural Disasters,Governance Indicators,Hazard Risk Management

    Nonsteady-Flow Thrust Augmenting Ejectors

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    Ejector augmenters in which the transfer of mechanical energy from the primary to the secondary flow takes place through the work of interface pressure forces are investigated. Nonsteady flow processes are analyzed from the standpoint of energy transfer efficiency and a comparison of a rotary jet augmenter to an ejector is presented

    DEMOCRATIC DECONSOLIDATION IN DEVELOPED DEMOCRACIES, 1995-2018. CES Open Forum Series 2018-2019

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    Until recently, many political scientists had believed that the stability of democracy is assured once certain threshold conditions – prosperity, democratic legitimacy, the development of a robust civil society – were attained. Democracy would then be consolidated, and remain stable. In this article we show that levels of support for democratic governance are not stable over time, even among high-income democracies, and have declined in recent years. In contrast to theories of democratic consolidation, we suggest that just as democracy can come to be “the only game in town” through processes of democratic deepening and the broad-based acceptance of democratic institutions, so too a process of democratic deconsolidation can take place as citizens sour on democratic institutions, become more open to authoritarian alternatives, and vote for anti-system parties. Public opinion measures of democratic deconsolidation are strongly associated with subsequent declines in the actual extent of democratic governance and predict not only recent democratic backsliding in transitional democracies, such as Venezuela or Russia, but also anticipated the downgrades in Freedom House scores occurring across a range of western democracies since 2016

    Drawn Together: Collaborative Performance

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    In the collaborative work of Drawn Together, a group formed by the artists Maryclare Foá, Jane Grisewood, Birgitta Hosea and Carali McCall, diverse practices are collectively materialised through performance drawing. Focusing on the notion of fragmentation has been instructive in identifying how the collaboration binds together a series of fragments and discontinuities that are enacted and reassembled in unpredictable and new ways

    Floquet topological transitions in a driven one-dimensional topological insulator

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    The Su-Schrieffer-Heeger model of polyacetylene is a paradigmatic Hamiltonian exhibiting non-trivial edge states. By using Floquet theory we study how the spectrum of this one-dimensional topological insulator is affected by a time-dependent potential. In particular, we evidence the competition among different photon-assisted processes and the native topology of the unperturbed Hamiltonian to settle the resulting topology at different driving frequencies. While some regions of the quasienergy spectrum develop new gaps hosting Floquet edge states, the native gap can be dramatically reduced and the original edge states may be destroyed or replaced by new Floquet edge states. Our study is complemented by an analysis of Zak phase applied to the Floquet bands. Besides serving as a simple example for understanding the physics of driven topological phases, our results could find a promising test-ground in cold matter experiments

    The effects of splenic irradiation on lymphocyte subpopulations in chronic B-lymphocytic leukemia

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    We describe the effect of splenic irradiation (SI) (0,5–1 Gy weekly) on lymphocyte subpopulations for 7 patients with progressive B chronic B-lymphocytic leukemia (B-CLL). Using specific cellular characteristics we could distinguish normal from abnormal cells. The irradiation resulted in a decrease of lymph node size, reduction in spleen volume and decrease in peripheral blood lymphocytes. The one exception was a patient with a prolymphocytoid transformation of B-CLL. For 3 patients SI had to be interrupted or stopped because of severe cytopenia. Quantitation of malignant B cells and normal T lymphocytes revealed that the total irradiation dose which resulted in a specific decrease of malignant lymphocytes varied from patient to patient. Normal T-cell subpopulations, which were increased before SI, decreased to normal or abnormally low values during SI. In previously untreated patients, natural killer (NK) cell numbers decreased more rapidly than T-cell subpopulations. For 2 patients refractory to chemotherapy an increase of NK cells was observed upon SI

    Antiresonances as precursors of decoherence

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    We show that, in presence of a complex spectrum, antiresonances act as a precursor for dephasing enabling the crossover to a fully decoherent transport even within a unitary Hamiltonian description. This general scenario is illustrated here by focusing on a quantum dot coupled to a chaotic cavity containing a finite, but large, number of states using a Hamiltonian formulation. For weak coupling to a chaotic cavity with a sufficiently dense spectrum, the ensuing complex structure of resonances and antiresonances leads to phase randomization under coarse graining in energy. Such phase instabilities and coarse graining are the ingredients for a mechanism producing decoherence and thus irreversibility. For the present simple model one finds a conductance that coincides with the one obtained by adding a ficticious voltage probe within the Landauer-Buettiker picture. This sheds new light on how the microscopic mechanisms that produce phase fluctuations induce decoherence.Comment: 7 pages, 2 figures, to appear in Europhys. Let

    Primary mediastinal lymphoma: diagnosis and treatment options.

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    Primary mediastinal large B-cell lymphoma (PMBCL) is a unique B-cell lymphoma variant that arises from a putative thymic medulla B cell. It constitutes 2-4% of non-Hodgkin lymphomas and occurs most frequently in young females. PMBCL is characterized by a diffuse proliferation of medium-to-large B cells associated with sclerosis. Molecular analysis shows that PMBCL is a distinct entity compared to other types of diffuse large B-cell lymphomas. PMBCL is characterized by a locally invasive anterior mediastinal bulky mass. The combination of rituximab with CHOP/CHOP-like regimens followed by mediastinal radiation therapy (RT) is associated with a 5-year progression-free survival of 75-85%. However, the role of consolidation RT still remains uncertain. More intensive regimens, such as DA-EPOCH-R without mediastinal RT, have shown very promising results. The conclusive role of PET-CT scan requires prospective studies and there is hope that this may allow to de-escalate RT and accordingly yield reliable prognostic information

    Hierarchy of Floquet gaps and edge states for driven honeycomb lattices

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    Electromagnetic driving in a honeycomb lattice can induce gaps and topological edge states with a structure of increasing complexity as the frequency of the driving lowers. While the high frequency case is the most simple to analyze we focus on the multiple photon processes allowed in the low frequency regime to unveil the hierarchy of Floquet edge-states. In the case of low intensities an analytical approach allows us to derive effective Hamiltonians and address the topological character of each gap in a constructive manner. At high intensities we obtain the net number of edge states, given by the winding number, with a numerical calculation of the Chern numbers of each Floquet band. Using these methods, we find a hierarchy that resembles that of a Russian nesting doll. This hierarchy classifies the gaps and the associated edge states in different orders according to the electron-photon coupling strength. For large driving intensities, we rely on the numerical calculation of the winding number, illustrated in a map of topological phase transitions. The hierarchy unveiled with the low energy effective Hamiltonians, alongside with the map of topological phase transitions discloses the complexity of the Floquet band structure in the low frequency regime. The proposed method for obtaining the effective Hamiltonian can be easily adapted to other Dirac Hamiltonians of two dimensional materials and even the surface of a 3D topological insulator.Comment: Phys. Rev. A 91, 04362

    Inelastic Quantum Transport and Peierls-like Mechanism in Carbon Nanotubes

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    We report on a theoretical study of inelastic quantum transport in (3m,0)(3m,0) carbon nanotubes. By using a many-body description of the electron-phonon interaction in Fock space, a novel mechanism involving optical phonon emission (absorption) is shown to induce an unprecedented energy gap opening at half the phonon energy, ω0/2\hbar\omega_{0}/2, above (below) the charge neutrality point. This mechanism, which is prevented by Pauli blocking at low bias voltages, is activated at bias voltages in the order of ω0\hbar\omega_{0}.Comment: 4 pages, 4 figure
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