Star fows and multisingular hyperbolicity

A vector field X is called a star flow if every periodic orbit, of any vector field C1-close to X, is hyperbolic. It is known that the chain recurrence classes of a generic star flow X on a 3 or 4 manifold are either hyperbolic or singular hyperbolic (see [MPP] for 3-manifolds and [GLW] on 4-manifolds). As it is defined, the notion of singular hyperbolicity forces the singularities in the same class to have the same index. However, in higher dimension (i.e $\geq 5$) \cite{BdL} shows that singularities of different indices may be robustly in the same chain recurrence class of a star flow. Therefore the usual notion of singular hyperbolicity is not enough for characterizing the star flows. We present a form of hyperbolicity (called multi-singular hyperbolic) which makes compatible the hyperbolic structure of regular orbits together with the one of singularities even if they have different indices. We show that multisingular hyperbolicity implies that the flow is star, and conversely, there is a C1-open and dense subset of the an open set of star flows which are multisingular hyperbolic. More generally, for most of the hyperbolic structures (dominated splitting, partial hyperbolicity etc...) well defined on regular orbits, we propose a way for generalizing it to a compact set containing singular points.Comment: There are new results in section 7 compared with the previous versio

The Paraconsistent Approach to Quantum Superpositions Reloaded: Formalizing Contradictory Powers in the Potential Realm

In [7] the authors of this paper argued in favor of the possibility to consider a Paraconsistent Approach to Quantum Superpositions (PAQS). We claimed that, even though most interpretations of quantum mechanics (QM) attempt to escape contradictions, there are many hints -coming from present technical and experimental developments in QM- that indicate it could be worth while to engage in a research of this kind. Recently, Arenhart and Krause have raised several arguments against the PAQS [1, 2, 3]. In [11, 12] it was argued that their reasoning presupposes a metaphysical stance according to which the physical representation of reality must be exclusively considered in terms of the equation: Actuality = Reality. However, from a different metaphysical standpoint their problems disappear. It was also argued that, if we accept the idea that quantum superpositions exist in a (contradictory) potential realm, it makes perfect sense to develop QM in terms of a paraconsistent approach and claim that quantum superpositions are contradictory, contextual existents. Following these ideas, and taking as a standpoint an interpretation in terms of the physical notions of power and potentia put forward in [10, 12, 15], we present a paraconsistent formalization of quantum superpositions that attempts to capture the main features of QM.Comment: 26 pages, no figures. arXiv admin note: substantial text overlap with arXiv:1502.05081, arXiv:1404.5186, arXiv:1506.0737

The territorial-environmental perception in fishing zones

Geography was always concerned with the study of the relationship between social groups and the environment in which they interact as natural resources for their survival. This relationship was always intertwined by power determinations in the organization of forms of appropriation of natural resources, deriving different types of territorial assets. These territorial assets demonstrate a variety of actors, involved in a certain territory and materializing different actions for the appropriation of space and use of the natural resources. In the case of fishing this is not different, since we verified that fishing practice is witnessed by a variety of actors, fishermen, fishing community, fishing association, fishing zone and regulatory agencies. Each of these actors relate in specific ways to the fishing spaces and material specific actions to define the territory, adopting territorial assets and a diversity of perceptions which sometimes conflict to each other. This study is part of a research which, through direct field research, aims at accomplishing an analysis of the way of life of the fishermen of the Colony of Fishermen Z 62, headquartered in the municipal district of Breves, state of Pará, and of how they acknowledge their territory, in the way they interact with other actors which use the same territory in other ways unrelated to fishing

Autonomous Incident Response

Trabalho de Projeto de Mestrado, Segurança Informática, 2022, Universidade de Lisboa, Faculdade de CiênciasInformation security is a must-have for any organization willing to stay relevant and grow, it plays an important role as a business enabler, be it from a regulatory perspective or a reputation perspective. Having people, process, and technology to solve the ever growing number of security incidents as fast as possible and with the least amount of impact is a challenge for small and big companies. To address this challenge, companies started investing in Security Orchestration, Automation, and Response (SOAR) [39, 68, 70]. Security orchestration is the planning, integration, cooperation, and coordination of the activities of security tools and experts to produce and automate required actions in response to any security incident across multiple technology paradigms [40]. In other words, the use of SOAR is a way to translate the manual procedures followed by the security analysts into automated actions, making the process faster and scalable while saving on human resources budget. This project proposes a low-cost cloud native SOAR platform that is based on serverless computing, presenting the underlying details of its design. The performance of the proposed solution was evaluated through 364 real-world incidents related to 11 use cases in a large multinational enterprise. The results show that the solution is able to decrease the duration of the tasks by an average of 98.81% while having an operating expense of less than $65/month. Prior to the SOAR, it took the analyst 75.84 hours to perform manual tasks related to the 11 use cases. Additionally, an estimated 450 hours of the analyst’s time would be used to run the Update threat intelligence database use case. After the SOAR, the same tasks were automatically ran in 31.2 minutes and the Update threat intelligence database use case ran 9.000 times in 5.3 hours

Natural killer cell activation by dendritic cells: balancing inhibitory and activating signals

Natural killer (NK) cells have originally been identified by their spontaneous cytolytic potential against tumor cells, which, however, might result from pre-activation due to prior pathogen exposure. Resting NK cells, on the contrary, require activation by bystander antigen-presenting cells to reach their full functional competence. In this review, we will summarize studies on how dendritic cells (DCs), the most potent type of antigen-presenting cell, communicate with human NK cells to activate them in secondary lymphoid organs and to integrate signals from activated NK cells at sites of inflammation for their own maturation. Furthermore, we will review aspects of the immunological synapse, which mediates this cross-talk. These studies provide the mechanistic understanding of how mature DCs can activate NK cells and survive to go on for the activation of adaptive immunity. This feature of DCs, to activate different waves of immune responses, could be harnessed for immunotherapies, including vaccination

Defrost Cycle Optimization for Fan-Supplied Tube-Fin Evaporators Subjected to Frosting Conditions

Frost accretion on a tube-fin evaporator surface raises its thermal and hydraulic resistances, which in turn deteriorates the cooling capacity of the refrigeration system. For this reason, periodic defrost operations are required to recover the initial performance of the system. Most defrost techniques rely on supplying heat to the frost layer. Due to technological and thermodynamic limitations, only part of the heat supply is effectively used to melt the frost built-up on the evaporator, while the rest increases the refrigerator thermal load. Therefore, the amount of heat dissipated, the duration of a defrost operation, and the time between two consecutives defrost operations must be considered for properly designing the defrost system. The present paper assesses, by means of a simulation model that considers the airflow reduction with frost accretion, the effects of evaporator operating and geometric conditions, and defrost cycle parameters on the time-averaged cooling capacity. The results pointed out the existence of an optimum time for the defrost operation, indicating that short intervals between two defrost operations increase the thermal load by frequent heat supply, whilst long intervals promote severe capacity depletion by frost clogging