Endomorphisms of Koszul complexes: formality and application to deformation theory

We 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

Lie Methods in Deformation Theory

Deformation theory is an important subject in algebra and algebraic gemetry, whose origin dates back to Kodaira, Spencer, Kuranishi, Gerstenhaber and Grothendieck. In the last 30 year a new approach, based on some ideas from rational homotopy theory, has permitted non only to solve some long standing open problems, but also to clarify the general theory and to relate apperently different features. This approach works over a field of characteristic 0 and the central role is played by the notions of differential graded Lie algebra and L-infinity algebra

An algebraic proof of Bogomolov-Tian-Todorov theorem

We give a completely algebraic proof of the Bogomolov-Tian-Todorov theorem. More precisely, we shall prove that if X is a smooth projective variety with trivial canonical bundle defined over an algebraically closed field of characteristic 0, then the L-infinity algebra governing infinitesimal deformations of X is quasi-isomorphic to an abelian differential graded Lie algebra.Comment: 20 pages, amspro

Formality conjecture for minimal surfaces of Kodaira dimension 0

Let be a polystable sheaf on a smooth minimal projective surface of Kodaira dimension 0. Then the differential graded (DG) Lie algebra of derived endomorphisms of is formal. The proof is based on the study of equivariant 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

L∞ liftings of semiregularity maps via Chern–Simons classes

We introduce the notion of Chern–Simons classes for curved DG-pairs and we prove that a particular case of this general construction provides canonical L∞ liftings of Buchweitz–Flenner semiregularity maps for coherent sheaves on complex manifolds

Restoring an eroded legitimacy: the adaptation of nonfinancial disclosure after a scandal and the risk of hypocrisy

Purpose \u2013 This study contributes to the literature on hypocrisy in corporate social responsibility by investigating how organizations adapt their nonfinancial disclosure after a social, environmental or governance scandal. Design/methodology/approach \u2013 The present research employs content analysis of nonfinancial disclosures by 11 organizations during a 3-year timespan to investigate how they responded to major scandals in terms of social, environmental and sustainability reporting and a content analysis of independent counter accounts to detect the presence of views that contrast with the corporate disclosure and suggest hypocritical behaviors. Findings \u2013 Four patterns in the adaptation of reporting \u2013 genuine, allusive, evasive, indifferent \u2013 emerge from information collected on scandals and socially responsible actions. The type of scandal and cultural factors can influence the response to a scandal, as environmental and social scandal can attract more scrutiny than financial scandals. Companies exposed to environmental and social scandals are more likely to disclose information about the scandal and receive more coverage by external parties in the form of counter accounts. Originality/value \u2013 Using a theoretical framework based on legitimacy theory and organizational hypocrisy, the present research contributes to the investigation of the adaptation of reporting when a scandal occurs and during its aftermath

Radiocarbon Dating in Late-Roman and Medieval Contexts: An Archaeological Excavation in the Center of Florence, Italy

A series of samples for radiocarbon dating were collected in 2005 from the Biblioteca Magliabechiana archaeological excavation area in the center of Florence, Italy, in a project directed by the Dipartimento di Archeologia e Storia delle Arti of the University of Siena, in cooperation with the Soprintendenza per i Beni Architettonici e per il Paesaggio per le province di Firenze e Prato. This area is located near the Uffizi Galleries, close to the Roman town, the Arno River and one of its former tributaries. The area is peculiar for the Florentine urban context because it was free from urban development until the 12th century AD. The exposed stratigraphy showed the presence of several layers composed of natural sediments, partly the result of historical floods. Here, we report a series of 14C measurements on charcoal and seed samples collected on this excavation. 14C dating has been performed in the LABEC laboratory in Florence, on the accelerator mass spectrometry (AMS) beam line of the AMS-IBA 3MV Tandetron accelerator. We also had the opportunity to compare the 14C dates obtained with several series of samples previously collected in nearby archaeological areas. Results were consistent with the data obtained previously and, moreover, offer interesting new aspects to the interpretation of the archaeological findings

An all-glass microfluidic network with integrated amorphous silicon photosensors for on-chip monitoring of enzymatic biochemical assay

A lab-on-chip system, integrating an all-glass microfluidics and on-chip optical detection, was developed and tested. The microfluidic network is etched in a glass substrate, which is then sealed with a glass cover by direct bonding. Thin film amorphous silicon photosensors have been fabricated on the sealed microfluidic substrate preventing the contamination of the micro-channels. The microfluidic network is then made accessible by opening inlets and outlets just prior to the use, ensuring the sterility of the device. The entire fabrication process relies on conventional photolithographic microfabrication techniques and is suitable for low-cost mass production of the device. The lab-on-chip system has been tested by implementing a chemiluminescent biochemical reaction. The inner channel walls of the microfluidic network are chemically functionalized with a layer of polymer brushes and horseradish peroxidase is immobilized into the coated channel. The results demonstrate the successful on-chip detection of hydrogen peroxide down to 18 mu M by using luminol and 4-iodophenol as enhancer agent