Interpretable and Generalizable Person Re-Identification with Query-Adaptive Convolution and Temporal Lifting

For person re-identification, existing deep networks often focus on representation learning. However, without transfer learning, the learned model is fixed as is, which is not adaptable for handling various unseen scenarios. In this paper, beyond representation learning, we consider how to formulate person image matching directly in deep feature maps. We treat image matching as finding local correspondences in feature maps, and construct query-adaptive convolution kernels on the fly to achieve local matching. In this way, the matching process and results are interpretable, and this explicit matching is more generalizable than representation features to unseen scenarios, such as unknown misalignments, pose or viewpoint changes. To facilitate end-to-end training of this architecture, we further build a class memory module to cache feature maps of the most recent samples of each class, so as to compute image matching losses for metric learning. Through direct cross-dataset evaluation, the proposed Query-Adaptive Convolution (QAConv) method gains large improvements over popular learning methods (about 10%+ mAP), and achieves comparable results to many transfer learning methods. Besides, a model-free temporal cooccurrence based score weighting method called TLift is proposed, which improves the performance to a further extent, achieving state-of-the-art results in cross-dataset person re-identification. Code is available at https://github.com/ShengcaiLiao/QAConv.Comment: This is the ECCV 2020 version, including the appendi

Hole Doping Dependence of the Coherence Length in La2−xSrxCuO4La_{2-x}Sr_xCuO_4 Thin Films

By measuring the field and temperature dependence of magnetization on systematically doped $La_{2-x}Sr_xCuO_4$ thin films, the critical current density $j_c(0)$ and the collective pinning energy $U_p(0)$ are determined in single vortex creep regime. Together with the published data of superfluid density, condensation energy and anisotropy, for the first time we derive the doping dependence of the coherence length or vortex core size in wide doping regime directly from the low temperature data. It is found that the coherence length drops in the underdoped region and increases in the overdoped side with the increase of hole concentration. The result in underdoped region clearly deviates from what expected by the pre-formed pairing model if one simply associates the pseudogap with the upper-critical field.Comment: 4 pages, 4 figure

Stripe, checkerboard, and liquid-crystal ordering from anisotropic p-orbital Fermi surfaces in optical lattices

We study instabilities of single-species fermionic atoms in the p-orbital bands in two-dimensional optical lattices at noninteger filling against interactions. Charge density wave and orbital density wave orders with stripe or checkerboard patterns are found for attractive and repulsive interactions, respectively. The superfluid phase, usually expected of attractively interacting fermions, is strongly suppressed. We also use field theory to analyze the possible phase-transitions from orbital stripe order to liquid-crystal phases and obtain the phase diagram. The condition of nearly-perfect Fermisurface nesting, which is key to the above results, is shown robustly independent of fermion fillings in such p-orbital systems, and the $(2k_F,\pm2k_F)$ momentum of density wave oscillation is highly tunable. Such remarkable features show the promise of making those exotic orbital phases, which are of broad interest in condensed-matter physics, experimentally realizable with optical lattice gases.Comment: final version, 8 pages, 5 figure

The role of ectopic human chorionic gonadotropin beta subunit in inducing epithelial mesenchymal transition in human keratinocytes and its possible pathways

Background: The process of epithelial-mesenchymal transition (EMT) involves the trans-differentiation of epithelial cells to mesenchymal cells associated with high plasticity. It usually occurs when the cells acquire migratory and invasive characteristics due to the weakening or the loss of cell-cell adhesion. Human chorionic gonadotropin (hCG), a pregnancy hormone, consists of a common α subunit which is shared by three other hormones, thyroid stimulating hormone, luteinizing hormone and follicular stimulating hormone; and an unique β subunit (hCGβ). Previous studies have demonstrated that hCGβ was expressed by some epithelial origin cancers (1, 2, 3) and therefore it has been postulated as a possible epithelial cancer biomarker. Other studies have linked the presence hCGβ to the aggressive and invasive behavior of certain cancers and their poor prognosis (3, 4). Methods: This study was set out to investigate whether hCGβ plays a role in inducing the EMT and to elucidate the possible pathways. Human keratinocytes (HK) were exposed to spent media collected from hCGβ producing cancer cells (ScaBER cells) for 48 hours before the cells were either fixed for immnuostaining or cells were lysed and protein extracts were collected for western blotting analysis. The expression of epithelial and mesenchymal markers was evaluated by both florescent immunocytochemistry and western blotting techniques. Results: A trend of up-regulation of mesenchymal markers (Vimentin and β-catenin) and down regulation of epithelial marker (E-cadherin) in these treated HK cells was observed. There was 50% increase in cell number which was positively stained by anti-Vimentin antibody whilst 16% of the cells have lost E-cadherin expression (100% to 84%) following 48 hours’ exposure to the hCGβ containing media. These findings were in consistence with the results from HK cells that were exposed to recombinant hCGβ (r-hCGβ). It was also observed that the changes in the expressions of these markers were reduced when a combination of three anti-hCGβ antibodies targeting different hCGβ epitopes was added to the spent media. These results were confirmed by western blotting analysis. Conclusion: The findings suggest that ectopic hCGβ produced by cancer cells might be involved in EMT associated with the migratory and aggressive behavior of such cancers. Furthermore, the up-regulation of β-catenin also suggests its possible role in the Wnt pathway which offers an insight into EMT process at a molecular level. This could be valuable point in developing future novel anti hCGβ therapies for such types of cancers

Bose-Einstein supersolid phase for a novel type of momentum dependent interaction

A novel class of non-local interactions between bosons is found to favor a crystalline Bose-Einstein condensation ground state. By using both low energy effective field theory and variational wavefunction method, we compare this state not only with the homogeneous superfluid, as has been done previously, but also with the normal (non-superfluid) crystalline phase and obtain the phase diagram. The key characters are: the interaction potential displays a negative minimum at finite momentum which determines the wavevector of this supersolid phase; and the wavelength corresponding to the momentum minimum needs to be greater than the mean inter-boson distance.Comment: 4 pages 3 figures, fig 1 and fig 2 update

Nano- and macro-scale characterisation of the mechanical properties of bovine bone

In the present study, nano- and macro-scale characterisations on the mechanical properties of bovine cortical bones have been performed by using nanoindentation and conventional compressive tests. Nanoindentation results showed that the elastic modulus for the osteons and the interstitial lamellae in the longitude direction were 24.7 &plusmn; 2.5 GPa and 30.1 &plusmn; 2.4 GPa. As it&rsquo;s difficult to distinguish osteons from interstitial lamellae in the transverse direction, the average elastic modulus for cortical bovine bone in the transverse direction was 19.8 &plusmn; 1.6 GPa. Significant differences were found in the modulus values between different microstructures of bone tissue and in different testing direction. It was found that the elastic modulus of bone bovine material in nano-level was higher than that in macro-level. The elastic modulus andultimate stress of large bone samples were 12.5 &plusmn; 1.9 GPa and 195 &plusmn; 19 MPa respectively from the compression test.<br /