42,411 research outputs found
Entangling Moving Cavities in Noninertial Frames
No full textAn open question in the field of relativistic quantum information is how parties in arbitrary motion may distribute and store quantum entanglement. We propose a scheme for storing quantum information in the field modes of cavities moving in flat space-time and analyze it in a quantum field theoretical framework. In contrast with previous work that found entanglement degradation between observers moving with uniform acceleration, we find the quantum information in such systems is protected. We further discuss a method for establishing the entanglement in the first place and show that in principle it is always possible to produce maximally entangled states between the cavities.</p
Heterogeneous and tissue-specific regulation of effector T cell responses by IFN-gamma during Plasmodium berghei ANKA infection.
No full textIFN-γ and T cells are both required for the development of experimental cerebral malaria during Plasmodium berghei ANKA infection. Surprisingly, however, the role of IFN-γ in shaping the effector CD4(+) and CD8(+) T cell response during this infection has not been examined in detail. To address this, we have compared the effector T cell responses in wild-type and IFN-γ(-/-) mice during P. berghei ANKA infection. The expansion of splenic CD4(+) and CD8(+) T cells during P. berghei ANKA infection was unaffected by the absence of IFN-γ, but the contraction phase of the T cell response was significantly attenuated. Splenic T cell activation and effector function were essentially normal in IFN-γ(-/-) mice; however, the migration to, and accumulation of, effector CD4(+) and CD8(+) T cells in the lung, liver, and brain was altered in IFN-γ(-/-) mice. Interestingly, activation and accumulation of T cells in various nonlymphoid organs was differently affected by lack of IFN-γ, suggesting that IFN-γ influences T cell effector function to varying levels in different anatomical locations. Importantly, control of splenic T cell numbers during P. berghei ANKA infection depended on active IFN-γ-dependent environmental signals--leading to T cell apoptosis--rather than upon intrinsic alterations in T cell programming. To our knowledge, this is the first study to fully investigate the role of IFN-γ in modulating T cell function during P. berghei ANKA infection and reveals that IFN-γ is required for efficient contraction of the pool of activated T cells
Wave turbulence of a rotating array of quantized vortices in the T → 0 temperature limit
No full textThe dynamics of quantized vortices in the zero temperature limit is currently of great interest, particularly in the case of the Fermi superfluid He-B. Here we study wave turbulence, generated by the librating motion of a rotating cylindrical container filled with He-B, in the limit of vanishing viscous forces at temperatures . The polarization of the quantized vortices with respect to the axis of rotation is measured using non-invasive NMR techniques. We observe a decrease of the polarization when the librating motion is started, and a two-stage relaxation process when the modulation of the rotation velocity is stopped. The first relaxation process is associated with the dissipation of large-scale flow stored in inertial waves and the solid body rotation of the vortex array. From the decay of these energy reservoirs we determine the rate of energy dissipation of large-scale flow. The later second process is related to the relaxation of Kelvin waves on individual vortices. This process is monitored by the recovery of the polarization. The existence of a Kelvin wave cascade at the lowest temperatures is currently a central open question. We supply some evidence for the cascade
Super-Eddington accretion and feedback from the first massive seed black holes
No full textSuper-Eddington accretion on to massive black hole seeds may be commonplace in the early Universe, where the conditions exist for rapid accretion. Direct-collapse black holes are often invoked as a possible solution to the observation of supermassive black holes (SMBHs) in the pre-reionization Universe. We investigate here how feedback, mainly in the form of bipolar jets, from super-Eddington accreting seed black holes will affect their subsequent growth. We find that, nearly independently of the mass loading of the bipolar jets, the violent outflows generated by the jets evacuate a region of approximately 0.1 pc surrounding the black hole seed. However, the jet outflows are unable to break free of the halo and their impact is limited to the immediate vicinity of the black hole. The outflows suppress any accretion for approximately a dynamical time. The gas then cools, recombines, and falls back to the centre, where high accretion rates are again observed. The overall effect is to create an effective accretion rate with values of between 0.1 and 0.5 times the Eddington rate. If this episodic accretion rate is maintained for order 500 million years, then the black hole will increase in mass by a factor of between 3 and 300 but far short of the factor of 104 required for the seeds to become the SMBHs observed at z > 6. Therefore, direct-collapse black holes born into atomic cooling haloes and which experience strong negative mechanical feedback will require external influences (e.g. rapid major mergers with other haloes) to promote efficient accretion and reach SMBH masses within a few hundred million years
E-book : Industrial Transformation In The Developing World (author: Michael T. Rock & David P. Angel)
No full textArsip Kuliah Online 2010: E-book : Industrial Transformation In The Developing World (author: Michael T. Rock & David P. Angel
Letter from Carl Hayden to P. J Moran
No full textLetter from Carl T. Hayden to P. J. Moran concerning the alignment of the road to Bright Angel Trail
E-book : "industrial Transformations In The Developing World (author: Michael T. Rock & David. P Angel)
No full textArsip Kuliah Online 2010: E-book : "industrial Transformations In The Developing World (author: Michael T. Rock & David. P Angel
Letter from P. J. Moran to Carl Hayden
No full textLetter from P. J. Moran to Carl T. Hayden inquiring when construction will begin on the approach road to Bright Angel Trai
Measurement of the ratio of prompt χ c to J / ψ production in pp collisions at √s = 7 TeV
No full textThe prompt production of charmonium χ c and J / ψ states is studied in proton-proton collisions at a centre-of-mass energy of √s = 7 TeV at the Large Hadron Collider. The χ c and J / ψ mesons are identified through their decays χ c → J / ψ γ and J / ψ → μ + μ - using 36 pb - 1 of data collected by the LHCb detector in 2010. The ratio of the prompt production cross-sections for χ c and J / ψ, σ (χ c → J / ψ γ) / σ (J / ψ), is determined as a function of the J / ψ transverse momentum in the range 2 < p T J / ψ < 15 GeV / c. The results are in excellent agreement with next-to-leading order non-relativistic expectations and show a significant discrepancy compared with the colour singlet model prediction at leading order, especially in the low p T J / ψ region
Letter from P. J. Moran to Carl Hayden
No full textLetter from P. J. Moran to Carl T. Hayden inquiring when construction will begin on the approach road to Bright Angel Trail
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