Nocturnal colony attendance by common guillemots Uria aalge at colony in Shetland during the pre-breeding season

No abstract available

Nocturnal colony attendance by common guillemots Uria aalge at colony in Shetland during the pre-breeding season

No abstract available

Smartphone app-induced habit: a therapeutic component in psychological treatment for obsessive-compulsive disorder

© 2023 Published by Elsevier B.V. This is an open access conference article under the Creative Commons Attribution-NonCommercial-NoDerivatives CC BY-NC-ND licence, https://creativecommons.org/licenses/by-nc-nd/4.0/Peer reviewe

Schur Polynomials and the Yang-Baxter equation

We show that within the six-vertex model there is a parametrized Yang-Baxter equation with nonabelian parameter group GL(2)xGL(1) at the center of the disordered regime. As an application we rederive deformations of the Weyl character formule of Tokuyama and of Hamel and King.Comment: Revised introduction; slightly changed reference

Flux-induced SUSY-breaking soft terms on D7-D3 brane systems

We study the effect of RR and NSNS 3-form fluxes on the effective action of the worldvolume fields of Type IIB D7/D3-brane configurations. The D7-branes wrap 4-cycles on a local Calabi-Yau geometry. This is an extension of previous work on hep-th/0311241, where a similar analysis was applied to the case of D3-branes. Our present analysis is based on the D7- and D3-brane Dirac-Born-Infeld and Chern-Simons actions, and makes full use of the R-symmetries of the system, which allow us to compute explicitly results for the fields lying at the D3-D7 intersections. A number of interesting new properties appear as compared to the simpler case of configurations with only D3-branes. As a general result one finds that fluxes stabilize some or all of the D7-brane moduli. We argue that this is important for the problem of stabilizing Kahler moduli through non-perturbative effects in KKLT-like vacua. We also show that (0,3) imaginary self-dual fluxes, which lead to compactifications with zero vacuum energy, give rise to SUSY-breaking soft terms including gaugino and scalar masses, and trilinear terms. Particular examples of chiral MSSM-like models of this class of vacua, based on D3-D7 brane systems at orbifold singularities are presented.Comment: 58 pages, no figures; v2: numerical factor in section 7.2 correcte

Three disks in a row: A two-dimensional scattering analog of the double-well problem

We investigate the scattering off three nonoverlapping disks equidistantly spaced along a line in the two-dimensional plane with the radii of the outer disks equal and the radius of the inner disk varied. This system is a two-dimensional scattering analog to the double-well-potential (bound state) problem in one dimension. In both systems the symmetry splittings between symmetric and antisymmetric states or resonances, respectively, have to be traced back to tunneling effects, as semiclassically the geometrical periodic orbits have no contact with the vertical symmetry axis. We construct the leading semiclassical ``creeping'' orbits that are responsible for the symmetry splitting of the resonances in this system. The collinear three-disk-system is not only one of the simplest but also one of the most effective systems for detecting creeping phenomena. While in symmetrically placed n-disk systems creeping corrections affect the subleading resonances, they here alone determine the symmetry splitting of the 3-disk resonances in the semiclassical calculation. It should therefore be considered as a paradigm for the study of creeping effects. PACS numbers: 03.65.Sq, 03.20.+i, 05.45.+bComment: replaced with published version (minor misprints corrected and references updated); 23 pages, LaTeX plus 8 Postscript figures, uses epsfig.sty, espf.sty, and epsf.te

Adaptive and reversible resistance to Kras inhibition in pancreatic cancer cells

Activating mutations in KRAS are the hallmark genetic alterations in pancreatic ductal adenocarcinoma (PDAC) and the key drivers of its initiation and progression. Longstanding efforts to develop novel KRAS inhibitors have been based on the assumption that PDAC cells are addicted to activated KRAS, but this assumption remains controversial. In this study, we analyzed the requirement of endogenous Kras to maintain survival of murine PDAC cells, using an inducible shRNA-based system that enables temporal control of Kras expression. We found that the majority of murine PDAC cells analyzed tolerated acute and sustained Kras silencing by adapting to a reversible cell state characterized by differences in cell morphology, proliferative kinetics, and tumor-initiating capacity. While we observed no significant mutational or transcriptional changes in the Kras-inhibited state, global phosphoproteomic profiling revealed significant alterations in cell signaling, including increased phosphorylation of focal adhesion pathway components. Accordingly, Kras-inhibited cells displayed prominent focal adhesion plaque structures, enhanced adherence properties, and increased dependency on adhesion for viability in vitro. Overall, our results call into question the degree to which PDAC cells are addicted to activated KRAS, by illustrating adaptive non-genetic and non-transcriptional mechanisms of resistance to Kras blockade. However, by identifying these mechanisms, our work also provides mechanistic directions to develop combination strategies that can help enforce the efficacy of KRAS inhibitors