377 research outputs found
Perturbative spectrum of Trapped Weakly Interacting Bosons in Two Dimensions
We study a trapped Bose-Einstein condensate under rotation in the limit of
weak, translational and rotational invariant two-particle interactions. We use
the perturbation-theory approach (the large-N expansion) to calculate the
ground-state energy and the excitation spectrum in the asymptotic limit where
the total number of particles N goes to infinity while keeping the total
angular momentum L finite. Calculating the probabilities of different
configurations of angular momentum in the exact eigenstates gives us a clear
view of the physical content of excitations. We briefly discuss the case of
repulsive contact interaction.Comment: Revtex, 10 pages, 1 table, to appear in Phys. Rev.
Vortex lattice of a Bose-Einstein Condensate in a rotating anisotropic trap
We study the vortex lattices in a Bose-Einstein Condensate in a rotating
anisotropic harmonic trap. We first investigate the single particle
wavefunctions obtained by the exact solution of the problem and give simple
expressions for these wavefunctions in the small anisotropy limit. Depending on
the strength of the interactions, a few or a large number of vortices can be
formed. In the limit of many vortices, we calculate the density profile of the
cloud and show that the vortex lattice stays triangular. We also find that the
vortex lattice planes align themselves with the weak axis of the external
potential. For a small number of vortices, we numerically solve the
Gross-Pitaevskii equation and find vortex configurations that are very
different from the vortex configurations in an axisymmetric rotating trap.Comment: 15 pages,4 figure
Improved induction of anti-melanoma T cells by adenovirus-5/3 fiber modification to target human DCs
To mount a strong anti-tumor immune response, non T cell inflamed (cold) tumors may require combination treatment encompassing vaccine strategies preceding checkpoint inhibition. In vivo targeted delivery of tumor-associated antigens (TAA) to dendritic cells (DCs), relying on the natural functions of primary DCs in situ, represents an attractive vaccination strategy. In this study we made use of a full-length MART-1 expressing C/B-chimeric adenoviral vector, consisting of the Ad5 capsid and the Ad3 knob (Ad5/3), which we previously showed to selectively transduce DCs in human skin and lymph nodes. Our data demonstrate that chimeric Ad5/3 vectors encoding TAA, and able to target human DCs in situ, can be used to efficiently induce expansion of functional tumor-specific CD8⁺ effector T cells, either from a naïve T cell pool or from previously primed T cells residing in the melanoma-draining sentinel lymph nodes (SLN). These data support the use of Ad3-knob containing viruses as vaccine vehicles for in vivo delivery. "Off-the-shelf" DC-targeted Ad vaccines encoding TAA could clearly benefit future immunotherapeutic approaches
Low-Lying Excitations from the Yrast Line of Weakly Interacting Trapped Bosons
Through an extensive numerical study, we find that the low-lying,
quasi-degenerate eigenenergies of weakly-interacting trapped N bosons with
total angular momentum L are given in case of small L/N and sufficiently small
L by E = L hbar omega + g[N(N-L/2-1)+1.59 n(n-1)/2], where omega is the
frequency of the trapping potential and g is the strength of the repulsive
contact interaction; the last term arises from the pairwise repulsive
interaction among n octupole excitations and describes the lowest-lying
excitation spectra from the Yrast line. In this case, the quadrupole modes do
not interact with themselves and, together with the octupole modes, exhaust the
low-lying spectra which are separated from others by N-linear energy gaps.Comment: 5 pages, RevTeX, 2 figures, revised version, submitted to PR
No V-Fe-Zn isotopic variation in basalts from the 2021 Fagradalsfjall eruption
The Earth’s mantle is chemically heterogeneous in space and time, which is often reflected by variable isotopic compositions of mantle derived basalts. Basalts from the first 40 days of the 2021 Fagradalsfjall eruption, Reykjanes Peninsula, Iceland, display systematic temporal variations in the ratios of incompatible elements alongside resolvable variations in Sr, Nd and Pb radiogenic isotopes. These variations reflect progressive influx of magma derived from melting of a deeper, more enriched and potentially lithologically distinct source. We use this eruptive time series to conduct the first combined V-Fe-Zn isotope study, exploring the sensitivity of the combined isotopic approach, with particular focus on fingerprinting source lithological heterogeneity. We find no analytically resolvable change in V (δ51VAA between −0.95 ± 0.09 ‰ 2 s.d. and −0.86 ± 0.07 ‰ 2 s.d.), Fe (δ56FeIRMM-524 between +0.047 ± 0.042 ‰ 2 s.d. and +0.094 ± 0.049 ‰ 2 s.d.) and Zn (δ66ZnAA-ETH between −0.042 ± 0.003 ‰ 2 s.d. and +0.013 ± 0.027 ‰ 2 s.d.) isotopic compositions. The lack of variability in V-Fe-Zn isotopes, despite the evolving trace element and radiogenic isotope ratios, suggests there is no significant contribution of melts from a lithologically distinct (pyroxenite) mantle component under the Reykjanes Peninsula
Multiply quantized vortices in trapped Bose-Einstein condensates
Vortex configurations in rotating Bose-Einstein condensed gases trapped in
power-law and anharmonic potentials are studied. When the confining potential
is steeper than harmonic in the plane perpendicular to the axis of rotation,
vortices with quantum numbers larger than one are energetically favorable if
the interaction is weak enough. Features of the wave function for small and
intermediate rotation frequencies are investigated numerically.Comment: 9 pages, 6 figures. Revised and extended article following referee
repor
On phases in weakly interacting finite Bose systems
We study precursors of thermal phase transitions in finite systems of
interacting Bose gases. For weakly repulsive interactions there is a phase
transition to the one-vortex state. The distribution of zeros of the partition
function indicates that this transition is first order, and the precursors of
the phase transition are already displayed in systems of a few dozen bosons.
Systems of this size do not exhibit new phases as more vortices are added to
the system.Comment: 7 pages, 2 figure
An automated high-throughput system for phenotypic screening of chemical libraries on C. elegans and parasitic nematodes
Parasitic nematodes infect hundreds of millions of people and farmed livestock. Further, plant parasitic nematodes result in major crop damage. The pipeline of therapeutic compounds is limited and parasite resistance to the existing anthelmintic compounds is a global threat. We have developed an INVertebrate Automated Phenotyping Platform (INVAPP) for high-throughput, plate-based chemical screening, and an algorithm (Paragon) which allows screening for compounds that have an effect on motility and development of parasitic worms. We have validated its utility by determining the efficacy of a panel of known anthelmintics against model and parasitic nematodes: Caenorhabditis elegans, Haemonchus contortus, Teladorsagia circumcincta, and Trichuris muris. We then applied the system to screen the Pathogen Box chemical library in a blinded fashion and identified compounds already known to have anthelmintic or anti-parasitic activity, including tolfenpyrad, auranofin, and mebendazole; and 14 compounds previously undescribed as anthelmintics, including benzoxaborole and isoxazole chemotypes. This system offers an effective, high-throughput system for the discovery of novel anthelmintics
Oscillations of a rapidly rotating annular Bose-Einstein condensate
A time-dependent variational Lagrangian analysis based on the
Gross-Pitaevskii energy functional serves to study the dynamics of a metastable
giant vortex in a rapidly rotating Bose-Einstein condensate. The resulting
oscillation frequencies of the core radius reproduce the trends seen in recent
experiments [Engels et al., Phys. Rev. Lett. 90, 170405 (2003)], but the
theoretical values are smaller by a factor approximately 0.6-0.8.Comment: 7 pages, revtex
Individual Goal Orientations, Team Empowerment, and Employee Creative Performance: A Case of Cross-Level Interactions
Intrigued by relationship between team motivational context and individual characteristics in the organizational reality, we developed and tested a cross-level model to investigate the interactive effects of team empowerment and individual goal orientations on individual creative performance through the mediating mechanism of an individual\u27s creative self-efficacy. Using multi-wave multi-source data from 63 R&D teams in three IT companies, we found that (1) team empowerment, individual learning goal orientation, and individual performance orientation are all positively related to individual creative performance through mediation of creative self-efficacy; (2) learning orientation and performance approach orientation could both supplement the effects of team empowerment on individual creative self-efficacy. Our findings point to the importance of individual goal orientation in shaping the effects of team motivation climates and provide insights for both scholars and practitioners. The specific practical implications include but are not limited to (1) individuals with learning and performance approach orientations should be identified during hiring procedures given that they could still thrive in less empowered teams and maintain a relatively high level of creative self-efficacy and creative outcomes; (2) managers should consider assigning employees who are more learning oriented to more empowering and open-ended tasks in order to obtain better creative results
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