Interplay between elastic fields due to gravity and a partial dislocation for a hard-sphere crystal coherently grown under gravity: driving force for defect disappearance

We previously observed that an intrinsic staking fault shrunk through a glide of a Shockley partial dislocation terminating its lower end in a hard-sphere crystal under gravity coherently grown in by Monte Carlo simulations [Mori et al., Molec. Phys. 105, 1377 (2007)]; it was an answer to a one-decade long standing question why the stacking disorder in colloidal crystals reduced under gravity [Zhu et al., Nature 387, 883 (1997)]. Here, we present an elastic energy calculation; in addition to the self-energy of the partial dislocation [Mori et al., Prog. Theor. Phys. Suppl. 178, 33 (2009)] we calculate the cross-coupling term between elastic field due to gravity and that due to a Shockley partial dislocation. The cross term is a increasing function of the linear dimension R over which the elastic field expands, showing that a driving force arises for the partial dislocation moving toward the upper boundary of a grain.Comment: 8pages, 4figures, to be published in Molecular Physic

STRAWMEN IN TRADE PROTECTIONISM: THE CASE OF CITRUS IMPORT QUOTAS

The hypothesis that shipments of oranges into Japan have displaced, and will continue to displace, domestic Mandarin orange shipments in Japan was tested using annual and monthly data and by estimating an econometric model. It was found that the marketing seasons of Mandarin and imported oranges are substantially different. This result, along with econometric estimates, indicated that Mandarin and imported oranges do not directly compete with each other, and supported rejection of the hypothesis that imported oranges have displaced Mandarin orange shipments. It was projected that, under full trade liberalization, orange imports would increase by 115 percent. However, most of this increase would occur during the April to September period when few Mandarin oranges are shipped.Crop Production/Industries, International Relations/Trade,

The Grothendieck Group of a Quantum Projective Space Bundle

We compute the Grothendieck group K_0 of non-commutative analogues of quantum projective space bundles. Our results specialize to give the Grothendieck groups of non-commutative analogues of projective spaces, and specialize to recover the Grothendieck group of a usual projective space bundle over a regular noetherian separated scheme. As an application we develop an intersection theory for the quantum ruled surfaces defined by Van den Bergh.Comment: This paper is being replaced so I can correct the metadata, the title! I (Paul) spelled Grothendieck's name incorrectly. The paper is being reposted with the journal reference and doi added to the metadat

Transverse self-modulation of ultra-relativistic lepton beams in the plasma wakefield accelerator

The transverse self-modulation of ultra-relativistic, long lepton bunches in high-density plasmas is explored through full-scale particle-in-cell simulations. We demonstrate that long SLAC-type electron and positron bunches can become strongly self-modulated over centimeter distances, leading to wake excitation in the blowout regime with accelerating fields in excess of 20 GV/m. We show that particles energy variations exceeding 10 GeV can occur in meter-long plasmas. We find that the self-modulation of positively and negatively charged bunches differ when the blowout is reached. Seeding the self-modulation instability suppresses the competing hosing instability. This work reveals that a proof-of-principle experiment to test the physics of bunch self-modulation can be performed with available lepton bunches and with existing experimental apparatus and diagnostics.Comment: 8 pages, 8 figures, accepted for publication in Physics of Plasma