Recent evidence that TADs and chromatin loops are dynamic structures.

Mammalian genomes are folded into spatial domains, which regulate gene expression by modulating enhancer-promoter contacts. Here, we review recent studies on the structure and function of Topologically Associating Domains (TADs) and chromatin loops. We discuss how loop extrusion models can explain TAD formation and evidence that TADs are formed by the ring-shaped protein complex, cohesin, and that TAD boundaries are established by the DNA-binding protein, CTCF. We discuss our recent genomic, biochemical and single-molecule imaging studies on CTCF and cohesin, which suggest that TADs and chromatin loops are dynamic structures. We highlight complementary polymer simulation studies and Hi-C studies employing acute depletion of CTCF and cohesin, which also support such a dynamic model. We discuss the limitations of each approach and conclude that in aggregate the available evidence argues against stable loops and supports a model where TADs are dynamic structures that continually form and break throughout the cell cycle

Ab Initio Approach to Second-order Resonant Raman Scattering Including Exciton-Phonon Interaction

Raman spectra obtained by the inelastic scattering of light by crystalline solids contain contributions from first-order vibrational processes (e.g. the emission or absorption of one phonon, a quantum of vibration) as well as higher-order processes with at least two phonons being involved. At second order, coupling with the entire phonon spectrum induces a response that may strongly depend on the excitation energy, and reflects complex processes more difficult to interpret. In particular, excitons (i.e. bound electron-hole pairs) may enhance the absorption and emission of light, and couple strongly with phonons in resonance conditions. We design and implement a first-principles methodology to compute second-order Raman scattering, incorporating dielectric responses and phonon eigenstates obtained from density-functional theory and many-body theory. We demonstrate our approach for the case of silicon, relating frequency-dependent relative Raman intensities, that are in excellent agreement with experiment, to different vibrations and regions of the Brillouin zone. We show that exciton-phonon coupling, computed from first principles, indeed strongly affect the spectrum in resonance conditions. The ability to analyze second-order Raman spectra thus provides direct insight into this interaction.Comment: 10 pages, 8 figure

The Espoused Theories of IS: A Study of General Editorial Statements.

In the IS field there has been an ongoing tradition to study the publication output of the community in order to evaluate the current and potential situation of IS research. In this work, we follow a different strategy and study what IS research claims to be. We look at those so-called 'espoused theories of IS' as found in the General Editorials Statements (GES) of IS journals. Based on the AISWorld journal ranking, we collected GES for 30 leading IS journals for the years 1997 and 2007. We applied thematic, lexicometric, and factor analyses to the datasets of the 1997 and the 2007 GES. Our results show that the representation of IS research in the GES has changed little over the last decade.Espoused Theory; Information Systems (IS); Research; Expectations; General Editorial Statement (GES); IS Journals; Thematic Analysis; Lexicometric Analysis;

Construction of a taxonomy for requirements engineering commercial-off-the-shelf components

This article presents a procedure for constructing a taxonomy of COTS products in the field of Requirements Engineering (RE). The taxonomy and the obtained information reach transcendental benefits to the selection of systems and tools that aid to RE-related actors to simplify and facilitate their work. This taxonomy is performed by means of a goal-oriented methodology inspired in GBRAM (Goal-Based Requirements Analysis Method), called GBTCM (Goal-Based Taxonomy Construction Method), that provides a guide to analyze sources of information and modeling requirements and domains, as well as gathering and organizing the knowledge in any segment of the COTS market. GBTCM claims to promote the use of standards and the reuse of requirements in order to support different processes of selection and integration of components.Facultad de Informátic

Quality evaluation of fresh and bloomed filled chocolates in House of Quality

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After the wildfires: the processes of social learning of forest owners' associations in central Catalonia, Spain

Over the last few decades, according to the Forest Fire Prevention Services of the Catalan Government, a small number of fires (less than 1%) have been responsible for the destruction of more than three quarters of the burnt forest area in Catalonia. However, while these wildfires have transformed many components of the landscape, including its vegetation and soils, they o er landowners the opportunity to learn from past decisions. This article aims to analyze the responses of forest owners in Central Catalonia after the great forest fires of the 1980s and 1990s, including the way in which their objectives and strategies are defined and their actions implemented. By conducting interviews with the members of forest owners' associations and by means of participant observation at association meetings, we seek to examine the processes of social learning experienced by this collective and to identify the mechanisms used in their e orts to create socio-ecological structures that are less vulnerable to fire. Associationism is unusual in the world of Catalan forest ownership, despite the great number of private forest areas. In our results, however, associationism emerges as a strategy for cooperation, a recognition of the need to link ecological and social structures in the territory, and one which we define as a form of 'socio-ecological resistance'. Our study highlights that the goals and actions of forest owners' associations have both an instrumental and emotional component, so that reason, emotion and action have come to form the three vertices of socio-ecological resistance to fire