A Brillouin torus decomposition for Chern insulators

Two-band Chern insulators are topologically classified by the Chern number, $c$, which is given by the integral of the Berry curvature of the occupied band over the Brillouin torus. The curvature itself comes from the imaginary part of a more basic object, the quantum geometric tensor, $Q$. On the other hand, the integral over the Brillouin torus of the real part of $Q$ gives rise to another magnitude, the quantum volume, $v_{g}$, that like $c$ also changes abruptly when the system undergoes a topological phase transition. Recently, the information about the topology of the system contained in the quantum volume has been investigated. In this paper we present new results regarding the underlying geometric structure of two-band Chern insulators. Since a generic model describing the system can be characterized by a map, the classifying map, from the Brillouin torus to the two-sphere, we study its properties at the geometric level. We present a procedure for splitting the Brillouin torus into different sectors in such a way that the classifying map when restricted to each of them is an injective immersion. By doing so, we show that $c$ and $v_{g}$ have a very rich inner structure, meaning that they are composed by different contributions that behave differently at the topological phase transition. In particular, some specific regions are found to be ones responsible for the non vanishing value of the topological invariant $c$. In addition, the present work makes contact with, and clarifies, some interpretations of the quantum volume in terms of the Euler characteristic number that were done in the recent literature. We illustrate our findings by a careful analysis of some selected models for Chern insulators corresponding to tight-binding Hamiltonians

Presentation of the 9th Edition of the Model Checking Contest.

International audience; The Model Checking Contest (MCC) is an annual competition of software tools for model checking. Tools must process an increasing benchmark gathered from the whole community and may participate in various examinations: state space generation, computation of global properties, computation of some upper bounds in the model, evaluation of reachability formulas, evaluation of CTL formulas, and evaluation of LTL formulas.For each examination and each model instance, participating tools are provided with up to 3600 s and 16 gigabyte of memory. Then, tool answers are analyzed and confronted to the results produced by other competing tools to detect diverging answers (which are quite rare at this stage of the competition, and lead to penalties).For each examination, golden, silver, and bronze medals are attributed to the three best tools. CPU usage and memory consumption are reported, which is also valuable information for tool developers

The Met oncogene and basal-like breast cancer: another culprit to watch out for?

Recent findings suggest the involvement of the MET oncogene, encoding the tyrosine kinase receptor for hepatocyte growth factor, in the onset and progression of basal-like breast carcinoma. The expression profiles of basal-like tumors - but not those of other breast cancer subtypes - are enriched for gene sets that are coordinately over-represented in transcriptional signatures regulated by Met. Consistently, tissue microarray analyses have revealed that Met immunoreactivity is much higher in basal-like cases of human breast cancer than in other tumor types. Finally, mouse models expressing mutationally activated forms of Met develop a high incidence of mammary tumors, some of which exhibit basal characteristics. The present review summarizes current knowledge on the role and activity of Met in basal-like breast cancer, with a special emphasis on the correlation between this tumor subtype and the cellular hierarchy of the normal mammary gland

Role of BRCA gene dysfunction in breast and ovarian cancer predisposition

Tumor suppressor genes that perform apparently generic cellular functions nonetheless cause tissue-specific syndromes in the human population when they are mutated in the germline. The two major hereditary breast/ovarian cancer predisposition genes, BRCA1 and BRCA2, appear to participate in a common pathway that is involved in the control of homologous recombination and in the maintenance of genomic integrity. How might such functions translate into the specific suppression of cancers of the breast and ovarian epithelia? Recent advances in the study of BRCA1 and BRCA2, discussed herein, have provided new opportunities to address this question

Breast cancer stem cells: implications for therapy of breast cancer

The concept of cancer stem cells responsible for tumour origin, maintenance, and resistance to treatment has gained prominence in the field of breast cancer research. The therapeutic targeting of these cells has the potential to eliminate residual disease and may become an important component of a multimodality treatment. Recent improvements in immunotherapy targeting of tumour-associated antigens have advanced the prospect of targeting breast cancer stem cells, an approach that might lead to more meaningful clinical remissions. Here, we review the role of stem cells in the healthy breast, the role of breast cancer stem cells in disease, and the potential to target these cells