The bar derived category of a curved dg algebra

Curved A-infinity algebras appear in nature as deformations of dg algebras. We develop the basic theory of curved A-infinity algebras and, in particular, curved dg algebras. We investigate their link with a suitable class of dg coalgebras via the bar construction and produce Quillen model structures on their module categories. We define the analogue of the relative derived category for a curved dg algebra.Comment: 38 pages, with figures, corrected typos. To appear in the Journal of Pure and Applied Algebr

On the (non)vanishing of some "derived" categories of curved dg algebras

Since curved dg algebras, and modules over them, have differentials whose square is not zero, these objects have no cohomology, and there is no classical derived category. For different purposes, different notions of "derived" categories have been introduced in the literature. In this note, we show that for some concrete curved dg algebras, these derived categories vanish. This happens for example for the initial curved dg algebra whose module category is the category of precomplexes, and for certain deformations of dg algebras.Comment: 18 pages, new title, several local modifications and correction

DETERMINING THE CELLULAR AND MOLECULAR CONSEQUENCES OF NATURALLY-OCCURRING AND ENGINEERED MUTATIONS IN THE CELL CYCLE GENE CDT1

The cell division cycle is composed of two major events; 1. DNA replication (S phase) and 2. chromosome segregation (M phase). In addition, gap phases exist to prepare cells for the duplication of their entire genome (G1 phase) and to check that the genome has been faithfully duplicated before cell division (G2 phase). This entire process involves many steps each governed by a set of molecular mechanisms that allow cells to transition from one cell cycle phase to the next. How these mechanisms are arranged and linked to intra- and extracellular cues for timely and coordinated cell division is a topic of great interest in the field. In this work, we focus on a critical step for cell cycle progression, known as origin licensing, with emphasis on elucidating the molecular function of Cdt1. The Cdt1 protein is highly conserved in metazoans and its role is essential for origin licensing, yet the mechanism of Cdt1 function is still incompletely understood. We examined a collection of rare Cdt1 variants that cause a form of primordial dwarfism (Meier-Gorlin syndrome) plus one hypomorphic Drosophila allele to shed light on Cdt1 function. Three hypomorphic variants load MCM less efficiently than WT Cdt1, and their lower activity correlates with impaired MCM binding. A structural homology model of the human Cdt1-MCM complex position the altered Cdt1 residues at two distinct interfaces rather than the previously described single MCM interaction domain. Surprisingly, one dwarfism allele (Cdt1-A66T) is more active than WT Cdt1. This hypermorphic variant binds both Cyclin A and SCFSkp2 poorly relative to WT Cdt1. Detailed quantitative live cell imaging analysis demonstrated no change in stability of this variant however. Instead, we propose that Cyclin A/CDK inhibits Cdt1 licensing function independently of the creation of the SCFSkp2 phosphodegron. Together, these findings identify key Cdt1 interactions required for both efficient origin licensing and tight Cdt1 regulation to ensure normal cell proliferation and genome stability. In addition, we present here recent advances in elucidating Cdt1 molecular functions in origin licensing as well as describe the current understanding of human Cdt1 regulation.Doctor of Philosoph

On excited states in real-time AdS/CFT

The Skenderis-van Rees prescription, which allows the calculation of time-ordered correlation functions of local operators in CFT’s using holographic methods is studied and applied for excited states. Calculation of correlators and matrix elements of local CFT operators between generic in/out states are carried out in global Lorentzian AdS. We find the precise form of such states, obtain an holographic formula to compute the inner product between them, and using the consistency with other known prescriptions, we argue that the in/out excited states built according to the Skenderis-Van Rees prescription correspond to coherent states in the (large-N) AdS-Hilbert space. This is confirmed by explicit holographic computations. The outcome of this study has remarkable implications on generalizing the Hartle-Hawking construction for wave functionals of excited states in AdS quantum gravity.Fil: Botta Cantcheff, Marcelo Angel Nicolas. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Física La Plata. Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Instituto de Física La Plata; ArgentinaFil: Martinez, Pedro Jorge. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Física La Plata. Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Instituto de Física La Plata; ArgentinaFil: Silva, Guillermo Ariel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Física La Plata. Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Instituto de Física La Plata; Argentin

Weak lensing of large scale structure in the presence of screening

A number of alternatives to general relativity exhibit gravitational screening in the non-linear regime of structure formation. We describe a set of algorithms that can produce weak lensing maps of large scale structure in such theories and can be used to generate mock surveys for cosmological analysis. By analysing a few basic statistics we indicate how these alternatives can be distinguished from general relativity with future weak lensing surveys.Comment: 25 pages, 7 figures, accepted by JCAP. v2: references updat