1,198 research outputs found
Formality conjecture for minimal surfaces of Kodaira dimension 0
No full textLet F be a polystable sheaf on a smooth minimal projective surface of Kodaira dimension 0. Then the differential graded (DG) Lie algebra RHom(F, F) of derived endomorphisms of F is formal. The proof is based on the study of equivariant L-infinity minimal models of DG Lie algebras equipped with a cyclic structure of degree 2 which is non-degenerate in cohomology, and does not rely (even for K3 surfaces) on previous results on the same subject
Recent Findings Confirm LIM Domain Kinases as Emerging Target Candidates for Cancer Therapy
No full textThe two members of the LIM domain kinase family (LIMK1 and LIMK2) represent crucial keys in the signaling pathways that modulate the structure and activity of actin cytoskeleton. They maintain the optimal balance between phosphorylated and unphosphorylated cofilin that in turn acts by severing filamentous actin into globular actin and ensures actin turnover and cytoskeleton regulation. Many macromolecular partners able to regulate LIMK activity (positive and negative regulators) do exist. Proteins that enhance or reduce the nucleocytoplasmic shuttling of LIMK by direct or indirect interaction are also known. Among many LIMK activators, members of the Rho family of small GTPases (i.e., Rho, Rac, and Cdc42) and their downstream effectors (i.e., ROCK, PAK, and MK2) are involved in the progression of various human cancers toward invasive and metastatic stages. As LIMK are centrally positioned in the pathways leading to cytoskeleton dynamics and regulation, they could be considered as valuable targets for actin regulation. Fine modulation of LIMK activity could be a major challenge to inhibit tumor cell invasion mediated by one or a combination of the upstream signaling factors. As LIMK play a critical role in tumor cell invasion, they may be candidate targets for developing novel therapeutic agents toward tumor invasion and metastasis
(a)-Topics and animacy
No full textThe aim of this paper is twofold: first, we intend to contribute to the debate on the identification of the features to which syntactic locality expressed in terms of the featural Relativized Minimality/ fRM principle appears to be sensitive (Rizzi 2004; Friedmann, Belletti & Rizzi 2009); second, we aim at providing a better characterization of the distributional and interpretive properties of the process of a-marking in the Topic position of the Italian left periphery identified by syntactic cartography, in relation to (in)animacy (Belletti & Manetti 2019). To these ends, we examined the role of animacy in a production experiment eliciting left dislocated topics with 5-year-old Italian-speaking children. To the extent that a-marking is related to a kind of affectedness of object topics (Belletti 2018a), we examined whether an inanimate left dislocated object could constitute a felicitous a-Topic. Furthermore, the question is directly addressed whether complexity effects in fRM configurations can be modulated in the animacy mismatch condition, with an inanimate left dislocated object and an intervening (animate) lexical subject in ClLDs. Our results show that, in the tested animacy mismatch condition, children seldom a-marked the pre-posed object. Instead, they appeared to creatively explore other solutions to overcome the production of the hard intervention structure, mainly using null subjects. As children are not ready to compute the intervention configuration with a lexical preverbal subject, but could not naturally adjust it through a-marking of the inanimate topic, they ended up opting for different types of productions in which intervention was eliminated. If the animacy feature seems to be implicated in the process of a-marking to some extent, it is not a feature to which the fRM principle is sensitive in building the object A’-dependency in ClLD: we conclude, in line with previous work, that animacy is not among the features implicated in triggering syntactic movement (in Italian). © 2021 The Author(s)
Deformations of algebraic schemes via Reedy–Palamodov cofibrant resolutions
No full textLet X be a Noetherian separated and finite dimensional scheme over a field K of characteristic zero. The goal of this paper is to study deformations of X over a differential graded local Artin K-algebra by using local Tate–Quillen resolutions, i.e., the algebraic analogous of the Palamodov's resolvent of a complex space. The above goal is achieved by describing the DG-Lie algebra controlling deformation theory of a diagram of differential graded commutative algebras, indexed by a direct Reedy category
Endomorphisms of Koszul complexes: formality and application to deformation theory
No full textWe study the differential graded Lie algebra of endomorphisms of the Koszul resolution of a regular sequence on a unitary commutative K-algebra R and we prove that it is homotopy abelian over K but not over R (except trivial cases). We apply this result to prove an annihilation theorem for obstructions of (derived) deformations of locally complete intersection ideal sheaves on projective schemes
Formal deformation theory in left-proper model categories
No full textWe develop the notion of deformation of a morphism in a left-proper model category. As an application we provide a geomet-ric/homotopic description of deformations of commutative (non-positively) graded differential algebras over a local DG-Artin ring
Formal deformation theory in left-proper model categories
No full textWe develop the notion of deformation of a morphism in a left-proper model category. As an application we provide a geomet-ric/homotopic description of deformations of commutative (non-positively) graded differential algebras over a local DG-Artin ring
Surfaces of Albanese general type and the Severi conjecture
No full textIn 1932, F. Severi claimed, with an incorrect proof, that every smooth minimal projective surface S of irregularity q = q(S) > 0 without irrational pencils of genus q satisfies the topological inequality 2c(1)(2) (S) greater than or equal to c(2) (S). According to the Enriques-Kodaira's classification, the above inequality is easily verified when the Kodaira dimension of the surface is less than or equal to 1, while for surfaces of general type it is still an open problem known as Severi's conjecture. In this paper we prove Severi's conjecture under the additional mild hypothesis that S has ample canonical bundle. Moreover, under the same assumption, we prove that 2c(1)(2)(S) = c(2) (S) if and only if S is a double cover of an abelian surface. (C) 2003 WILEY-VCH Verlag GmbH & Co. KGaA. Weinheim
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