371 research outputs found
Topology and quantum states: The electron-monopole system
This paper starts by describing the dynamics of the electronmonopole system at both classical and quantum level by a suitable reduction procedure. This suggests, in order to realise the space of states for quantum systems which are classically described on topologically non-trivial configuration spaces, to consider Hilbert spaces of exterior differential forms. Among the advantages of this
formulation, we present—in the case of the group SU(2), how it is possible to obtain all unitary irreducible representations on such a Hilbert space, and how it is possible to write scalar Dirac-type operators, following an idea by K¨ahler
Causality in Schwinger's Picture of Quantum Mechanics
This paper begins the study of the relation between causality and quantum mechanics, taking
advantage of the groupoidal description of quantum mechanical systems inspired by Schwinger’s
picture of quantum mechanics. After identifying causal structures on groupoids with a particular
class of subcategories, called causal categories accordingly, it will be shown that causal structures
can be recovered from a particular class of non-selfadjoint class of algebras, known as triangular
operator algebras, contained in the von Neumann algebra of the groupoid of the quantum system.
As a consequence of this, Sorkin’s incidence theorem will be proved and some illustrative examples
will be discussed.This researchwas funded by the Spanish Ministry of Economy and Competitiveness (MINECO), through the Severo Ochoa Programme for Centres of Excellence in RD (SEV-2015/0554), the MINECO research project PID2020-117477GB-I00, the Comunidad de Madrid project QUITEMAD+, S2013/ICE- 2801, the CONEX-Plus programme (University Carlos III of Madrid), Marie Sklodowska-Curie COFUND Action (H2020-MSCA-COFUND-2017-GA 801538). This work has been supported by the Madrid Government (Comunidad de Madrid-Spain) under the Multiannual Agreement with UC3M in the line of “Research Funds for Beatriz Galindo Fellowships” (C&QIG-BG-CM-UC3M), and in the context of the V PRICIT (Regional Programme of Research and Technological Innovation)
Optimal and Automated Deployment for Microservices
Microservices are highly modular and scalable Service Oriented Architectures.
They underpin automated deployment practices like Continuous Deployment and
Autoscaling. In this paper, we formalize these practices and show that
automated deployment - proven undecidable in the general case - is
algorithmically treatable for microservices. Our key assumption is that the
configuration life-cycle of a microservice is split into two phases: (i)
creation, which entails establishing initial connections with already available
microservices, and (ii) subsequent binding/unbinding with other microservices.
To illustrate the applicability of our approach, we implement an automatic
optimal deployment tool and compute deployment plans for a realistic
microservice architecture, modeled in the Abstract Behavioral Specification
(ABS) language
Tubulin nitration in human gliomas
Immunohistochem. and biochem. investigations showed that significant protein nitration occurs in human gliomas, esp. in grade IV glioblastomas at the level of astrocytes and oligodendrocytes and neurons. Enhanced alpha-tubulin immunoreactivity was co-present in the same elements in the glioblastomas. Proteomic methodologies were employed to identify a nitrated protein band at 55 kDa as alpha-tubulin. Peptide mass fingerprinting procedures demonstrated that tubulin is nitrated at Tyr224 in grade IV tumor samples but is unmodified in grade I samples and in non-cancerous brain tissue. These results provide the first characterization of endogenously nitrated tubulin from human tumor samples
Recording electrical activity from the brain of behaving octopus
: Octopuses, which are among the most intelligent invertebrates,1,2,3,4 have no skeleton and eight flexible arms whose sensory and motor activities are at once autonomous and coordinated by a complex central nervous system.5,6,7,8 The octopus brain contains a very large number of neurons, organized into numerous distinct lobes, the functions of which have been proposed based largely on the results of lesioning experiments.9,10,11,12,13 In other species, linking brain activity to behavior is done by implanting electrodes and directly correlating electrical activity with observed animal behavior. However, because the octopus lacks any hard structure to which recording equipment can be anchored, and because it uses its eight flexible arms to remove any foreign object attached to the outside of its body, in vivo recording of electrical activity from untethered, behaving octopuses has thus far not been possible. Here, we describe a novel technique for inserting a portable data logger into the octopus and implanting electrodes into the vertical lobe system, such that brain activity can be recorded for up to 12 h from unanesthetized, untethered octopuses and can be synchronized with simultaneous video recordings of behavior. In the brain activity, we identified several distinct patterns that appeared consistently in all animals. While some resemble activity patterns in mammalian neural tissue, others, such as episodes of 2 Hz, large amplitude oscillations, have not been reported. By providing an experimental platform for recording brain activity in behaving octopuses, our study is a critical step toward understanding how the brain controls behavior in these remarkable animals
Archiving and referencing source code with Software Heritage
Software, and software source code in particular, is widely used in modern
research. It must be properly archived, referenced, described and cited in
order to build a stable and long lasting corpus of scientic knowledge. In this
article we show how the Software Heritage universal source code archive
provides a means to fully address the first two concerns, by archiving
seamlessly all publicly available software source code, and by providing
intrinsic persistent identifiers that allow to reference it at various
granularities in a way that is at the same time convenient and effective. We
call upon the research community to adopt widely this approach.Comment: arXiv admin note: substantial text overlap with arXiv:1909.1076
GEANT4 : a simulation toolkit
Abstract Geant4 is a toolkit for simulating the passage of particles through matter. It includes a complete range of functionality including tracking, geometry, physics models and hits. The physics processes offered cover a comprehensive range, including electromagnetic, hadronic and optical processes, a large set of long-lived particles, materials and elements, over a wide energy range starting, in some cases, from 250 eV and extending in others to the TeV energy range. It has been designed and constructed to expose the physics models utilised, to handle complex geometries, and to enable its easy adaptation for optimal use in different sets of applications. The toolkit is the result of a worldwide collaboration of physicists and software engineers. It has been created exploiting software engineering and object-oriented technology and implemented in the C++ programming language. It has been used in applications in particle physics, nuclear physics, accelerator design, space engineering and medical physics. PACS: 07.05.Tp; 13; 2
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