8,829 research outputs found

    Lower Mass Bound on the WW^\prime mass via Neutrinoless Double Beta Decay in a 3-3-1 Model

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    The discovery of neutrino masses has raised the importance of studies in the context of neutrinoless double beta decay, which constitutes a landmark for lepton number violation. The standard interpretation is that the light massive neutrinos, that we observed oscillating in terrestrial experiments, mediate double beta decay. In the minimal 3-3-1 model, object of our study, there is an additional contribution that stems from the mixing between a new charged vector boson, WW^{\prime}, and the Standard Model W boson. Even after setting this mixing to be very small, we show that tight constraints arise from the non-observation of neutrinoless double beta decay. Indeed, we derive bounds on the mass of the WW^{\prime} gauge boson that might exceed those from collider probes, and most importantly push the scale of symmetry breaking beyond its validity, leading to the exclusion of the minimal 3-3-1 model.Comment: 16 pages, 5 figure

    Transmission Of Optical Coherent State Qubits

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    We discuss the long distance transmission of qubits encoded in optical coherent states. Through absorption these qubits suffer from two main types of errors, the reduction of the amplitude of the coherent states and accidental application of the Pauli Z operator. We show how these errors can be fixed using techniques of teleportation and error correcting codes.Comment: Added two pages of explanation/background/review material to increase readability and clarity. Corrected minor typographical and linguistic error

    Geologia e educação ambiental : a aprendizagem baseada na resolução de problemas como proposta metodológica

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    ara além de destacar o papel da geologia na educação ambiental (dimensão educativa de carácter transversal), o presente estudo apresenta a Aprendizagem Baseada na Resolução de Problemas como uma proposta metodológica para educar para o desenvolvimento sustentável. Nesse sentido, apresentam-se alguns dos resultados obtidos com a aplicação de um programa de intervenção realizado com 24 alunos do 3ºciclo do ensino básico (faixa etária dos 12-15 anos) e abordando a temática “Gestão Sustentável dos Recursos” Para além de 10 aulas de 45 minutos o programa contemplou uma saida de campo a uma antiga exploração mineira, local geologicamente relevante em termos de gestão sustentável de recursos minerais

    Perceptions and expectations of college students about the Internet of Things

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    The Internet is increasingly used as a means of communication of excellence. With the increasing ease and access to virtual communication, namely through social networks, it is verified that the relationships between people have assumed new forms of expression and higher levels of importance in society. In addition to communication between people, there is also an increasing possibility of any object communicating and connecting to other objects, with a unique way of identifying, anywhere, with devices connected to the Internet, this being the essential concept of Internet of Things (IoT). In this paper, our main goal is understand how college students represent IoT and what are their perceptions and expectations about it. From their point of view, is important to verify what is the impact that IoT may have on their personal lives, academic performance and in society. According to the methodology adopted we performed individual interviews with a population of college students. Data were processed through context analyses, after being transcribed and analyzed, using a typical software - Leximancer. Our findings showed that, in general, participants have an accurate perception about the Internet of Things, and how it works, and that they also have positive expectations in relation to it, considering it can be useful to our day-to-day life. Although, at the same time, they highlight the importance of being careful in terms of privacy, threats, vulnerabilities and risks associated to the internet.info:eu-repo/semantics/acceptedVersio

    Protocol-based verification of message-passing parallel programs

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    © 2015 ACM.We present ParTypes, a type-based methodology for the verification of Message Passing Interface (MPI) programs written in the C programming language. The aim is to statically verify programs against protocol specifications, enforcing properties such as fidelity and absence of deadlocks. We develop a protocol language based on a dependent type system for message-passing parallel programs, which includes various communication operators, such as point-to-point messages, broadcast, reduce, array scatter and gather. For the verification of a program against a given protocol, the protocol is first translated into a representation read by VCC, a software verifier for C. We successfully verified several MPI programs in a running time that is independent of the number of processes or other input parameters. This contrasts with alternative techniques, notably model checking and runtime verification, that suffer from the state-explosion problem or that otherwise depend on parameters to the program itself. We experimentally evaluated our approach against state-of-the-art tools for MPI to conclude that our approach offers a scalable solution

    Propagação assexuada da cana-do-reino (Arunda donax L.)

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