160 research outputs found
A rigid Calabi--Yau 3-fold
The aim of this paper is to analyze some geometric properties of the rigid
Calabi--Yau threefold obtained by a quotient of , where
is a specific elliptic curve. We describe the cohomology of and
give a simple formula for the trilinear form on . We describe
some projective models of and relate these to its generalized
mirror. A smoothing of a singular model is a Calabi--Yau threefold with small
Hodge numbers which was not known before.Comment: 24 pages, Version 2: minor changes, references adde
Orbital degeneracy loci and applications
Degeneracy loci of morphisms between vector bundles have been used in a wide
variety of situations. We introduce a vast generalization of this notion, based
on orbit closures of algebraic groups in their linear representations. A
preferred class of our orbital degeneracy loci is characterized by a certain
crepancy condition on the orbit closure, that allows to get some control on the
canonical sheaf. This condition is fulfilled for Richardson nilpotent orbits,
and also for partially decomposable skew-symmetric three-forms in six
variables. In order to illustrate the efficiency and flexibility of our
methods, we construct in both situations many Calabi--Yau manifolds of
dimension three and four, as well as a few Fano varieties, including some new
Fano fourfolds.Comment: To appear in Ann. Sc. Norm. Super. Pisa Cl. Sci. (5
Scattering diagrams and Jeffrey-Kirwan residues
We show that the consistent completion of an initial scattering diagram in
(for a finite rank lattice ) can be expressed quite
generally in terms of the Jeffrey-Kirwan residues of certain explicit
meromorphic forms, by using the Maurer-Cartan asymptotic analysis developed by
Chan-Leung-Ma and Leung-Ma-Young. A similar result holds for the associated
theta functions.Comment: Fixed a referenc
Mapping free resolutions of length three II -- Module formats
Let be a perfect module of projective dimension 3 in a Gorenstein, local
or graded ring . We denote by \FF the minimal free resolution of .
Using the generic ring associated to the format of \FF we define higher
structure maps, according to the theory developed by Weyman in "Generic free
resolutions and root systems" (Annales de l'Institut Fourier} 68.3 (2018), pp.
1241--1296). We introduce a generalization of classical linkage for -module
using the Buchsbaum--Rim complex, and study the behaviour of structure maps
under this Buchsbaum--Rim linkage. In particular, for certain formats we obtain
criteria for these -modules to lie in the Buchsbaum--Rim linkage class of a
Buchsbaum--Rim complex of length 3.Comment: 30 page
Transfected poly(I:C) activates different dsRNA receptors leading to apoptosis or immunoadjuvant response in androgen-independent prostate cancer cells
Background: Castration-resistant prostate cancer (CRPC) is refractory to chemo-radiotherapy.
Results: Transfection of the synthetic analog of dsRNA poly(I:C) simultaneously stimulates apoptosis and IFN- expression
through different pathways in androgen-independent prostate cancer (PCa) cells.
Conclusion: Dual parallel pathways triggered by distinct receptors activate direct and immunologically mediated antitumor
effects in advanced PCa.
Significance: The proapoptotic/immunoadjuvant poly(I:C)-Lipofectamine complex may offer new therapeutic insights into CRPC
TBA type equations and tropical curves
The Joyce integrable system and the corresponding Bridgeland\u2013Toledano-Laredo connections are fundamental objects associated with suitable abelian categories or, more generally, with a class of continuous families of stability data. We offer an overview of some of our work, mostly joint with M. Garcia Fernandez, focusing on equations of TBA type as a useful tool in the analysis of these objects and their deformations, and as a means to establish a connection with tropical geometry. \ua9 2016 World Scientific Publishing Company
TNF-α inhibits GDNF levels in Sertoli cells, through a NF-κB-dependent, HES1-dependent mechanism
Glial cell line-derived neurotrophic factor (GDNF) is a soluble molecule crucial for the regulation of the spermatogonial stem cells (SSC) of the testis. The effects of GDNF on target cells have been extensively described, but mechanisms underlying GDNF regulation are currently under investigation. In the nervous system, GDNF expression is regulated by pro-inflammatory cytokines including lipopolysaccharide (LPS), interleukin 1 beta (IL-1β), and tumor necrosis factor alpha (TNF-α) but the effect of these cytokines on GDNF expression in the testis is unclear
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