Static flux bias of a flux qubit using persistent current trapping

Qubits based on the magnetic flux degree of freedom require a flux bias, whose stability and precision strongly affect the qubit performance, up to a point of forbidding the qubit operation. Moreover, in the perspective of multiqubit systems, it must be possible to flux-bias each qubit independently, hence avoiding the traditional use of externally generated magnetic fields in favour of on-chip techniques that minimize cross-couplings. The solution discussed in this paper exploits a persistent current, trapped in a superconducting circuit integrated on chip that can be inductively coupled with an individual qubit. The circuit does not make use of resistive elements that can be detrimental for the qubit coherence. The trapping procedure allows to control and change stepwise the amount of stored current; after that, the circuit can be completely disconnected from the external sources. We show in a practical case how this works and how to drive the bias circuit at the required value.Comment: 5 figures submitted to Superconductor Science and Technolog

Evidence from Cochrane systematic reviews for the dissemination control of the COVID-19 infection

Introduction: The COVID-19 infection has high transmissibility and several measures have been adopted for dissemination control. Objective: To identify and summarize the evidence from the Cochrane systematic reviews (SR) on measures to control the dissemination of the COVID-19 infection. Study design: This review of Cochrane SR has carried out in the Division of Vascular and Endovascular Surgery and in the Division of Emergency Medicine and Evidence-Based Medicine of the Universidade Federal de São Paulo, Brazil. Methods: A comprehensive search in the Cochrane Database of Systematic Reviews retrieved all Cochrane SR directly related to control measures for the COVID-19 dissemination. The main characteristics and results of all included SR were summarized and discussed. Results: Three Cochrane SRs were included in the qualitative synthesis and they evaluated populational and individual measures to control the dissemination of COVID-19. Conclusion: Low-certainty evidence show that quarantine of people exposed to those confirmed or suspected COVID-19 cases prevented 44% - 81% of incident cases and 31% - 63% of deaths compared to no measures and as sooner the quarantine measures are implemented, greater costs are saved. High-confidence evidence showed that clear communication about infection control and prevention guidelines was vital to its implementation. Low-certainty evidence showed that people with a long gown had less contamination than those with a coverall, and the coverall was more difficult to doff. Other SRs are desirable for controlling the dissemination of the COVID-19 infection

Real Attribute Learning Algorithm.

This paper presents REAL, a Real-Valued Attribute Classification Tree Learning Algorithm. Several of the algorithm's unique features are explained by úe users' demands for a decision support tool to be used for evaluating financial operations strategies. Compared to competing algorithms, in our applications, REAL presents maj or advantages : (1) The REAL classification trees usually have smaller error rates. (2) A single conviction (or trust) measure at each leaf is more convenient than the traditional (probability, confidence-level) pair. (3) No need for an external pruning criterion

Intentional Sampling by Goal Optimization with Decoupling by Stochastic Perturbation

Intentional sampling methods are non-probabilistic procedures that select a group of individuals for a sample with the purpose of meeting specific prescribed criteria. Intentional sampling methods are intended for exploratory research or pilot studies where tight budget constraints preclude the use of traditional randomized representative sampling. The possibility of subsequently generalize statistically from such deterministic samples to the general population has been the issue of long standing arguments and debates. Nevertheless, the intentional sampling techniques developed in this paper explore pragmatic strategies for overcoming some of the real or perceived shortcomings and limitations of intentional sampling in practical applications

Hierarchical Forecasting with Polynomial Nets.

This article presents a two level hierarchical forecasting model developed in a consulting project for a Brazilian magazine publishing company. The first level uses a VARMA model and considers econometric variables. The second level takes into account qualitative aspects of each publication issue, and is based on polynomial networks generated by Genetic Programming (GP)

DESENVOLVIMENTO DE UM APLICATIVO PARA AUXÍLIO NA TOMADA DE DECISÃO PARA PEQUENOS AGRICULTORES

Pequenos produtores familiares são responsáveis por parte significativa da produção agrícola brasileira. Esses produtores podem ser beneficiados pela implantação de sensores meteorológicos e pela análise desses dados para apoiar decisões sobre o tratamento de seus cultivos. Uma variável importante para a qualidade dos produtos agrícolas é a quantidade de água disponível no solo durante o desenvolvimento dos cultivos. O presente trabalho desenvolveu e implantou um sistema de informação que utiliza sensores de baixo custo e plataformas gratuitas para geração e divulgação de dados meteorológicos. Os dados coletados são combinados com dados públicos de pluviosidade de uma estação na região e aplicados em um modelo de balanço hídrico. Este modelo apresenta indicadores de excedente e déficit hídrico que podem ser apresentados através de site na Internet, ou, de aplicativo para dispositivos móveis. Os resultados das variáveis medidas permitem um conhecimento mais aprofundado do microclima local. O produtor, tendo recebido a informação, pode usá-la como elemento para decisões sobre irrigação dos cultivos.  Por isso, é importante a participação dos agricultores na produção da solução tecnológica. Verifica-se também a relevância do trabalho em equipes interdisciplinares para a criação de soluções tecnológicas que auxiliem o manejo sustentável do meio ambient

TORC3: Token-Ring Clearing Heuristic for Currency Circulation

Clearing algorithms are at the core of modern payment systems, facilitating the settling of multilateral credit messages with (near) minimum transfers of currency. Traditional clearing procedures use batch processing based on MILP - mixed-integer linear programming algorithms. The MILP approach demands intensive computational resources; moreover, it is also vulnerable to operational risks generated by possible defaults during the inter-batch period. This paper presents TORC3 - the Token-Ring Clearing Algorithm for Currency Circulation. In contrast to the MILP approach, TORC3 is a real time heuristic procedure, demanding modest computational resources, and able to completely shield the clearing operation against the participating agents’ risk of default

Dimorphos's Orbit Period Change and Attitude Perturbation due to Its Reshaping after the DART Impact

On 2022 September 26 (UTC), NASA's Double Asteroid Redirection Test (DART) mission achieved a successful impact on Dimorphos, the secondary component of the near-Earth binary asteroid system (65803) Didymos. Subsequent ground-based observations suggest a significant reshaping of Dimorphos, with its equatorial axis ratio changing from 1.06 to ∼1.3. Here we report the effects of this reshaping event on Dimorphos's orbit and attitude. Given the reported reshaping magnitude, our mutual dynamics simulations show that approximately 125 s of the observed 33 minute orbit period change after the DART impact may have resulted from reshaping. This value, however, is sensitive to the precise values of Dimorphos's post-impact axis ratios and may vary by up to 2 times that amount, reaching approximately 250 s within the current uncertainty range. While the rotational state of the body is stable at the currently estimated axis ratios, even minor changes in these ratios or the introduction of shape asymmetry can render its attitude unstable. The perturbation to Dimorphos's orbital and rotational state delivered by the impact directly, combined with any reshaping, leads to a strong possibility for a tumbling rotation state. To accurately determine the momentum enhancement factor (β) through measurements by the European Space Agency's Hera spacecraft and to evaluate the effectiveness of the kinetic deflection technique for future planetary defense initiatives, the effects of reshaping should not be overlooked.This work was supported in part by the DART mission, NASA contract 80MSFC20D0004 to JHU/APL. R.N. acknowledges support from NASA/FINESST (NNH20ZDA001N). S.D.R. and M.J. acknowledge support from the Swiss National Science Foundation (project number 200021_207359). P.M. acknowledges funding support from the French Space Agency CNES and The University of Tokyo. P.P. acknowledges support from the grant Agency of the Czech Republic, grant 23-04946S. S.R.S. acknowledges support from the DART Participating Scientist Program, grant No. 80NSSC22K0318. A.C.B. and P.Y.L. acknowledge funding by the NEO-MAPP project 717 GA 870377, EC H2020-SPACE-718 2018-2020/H2020-SPACE-2019, and by MICINN (Spain) PGC2021, PID2021-125883NB-C21. P.Y.L. acknowledges funding from the European Space Agency OSIP contract N.4000136043/21/NL/GLC/my. A portion of this work was carried out at the Jet Propulsion Laboratory, California Institute of Technology, under a contract with the National Aeronautics and Space Administration (No. 80NM0018D0004)