40 research outputs found

    Laser-induced fluorescence studies of HfF+ produced by autoionization

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    Autoionization of Rydberg states of HfF, prepared using the optical-optical double resonance (OODR) technique, holds promise to create HfF+ in a particular Zeeman level of a rovibronic state for an electron electric dipole moment (eEDM) search. We characterize a vibronic band of Rydberg HfF at 54 cm-1 above the lowest ionization threshold and directly probe the state of the ions formed from this vibronic band by performing laser-induced fluorescence (LIF) on the ions. The Rydberg HfF molecules show a propensity to decay into only a few ion rotational states of a given parity and are found to preserve their orientation qualitatively upon autoionization. We show empirically that we can create 30% of the total ion yield in a particular |J+,M+> state and present a simplified model describing autoionization from a given Rydberg state that assumes no angular dynamics.Comment: 8 pages, 5 figure

    Near-Infrared LIF Spectroscopy of HfF

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    The molecular ion HfF⁺ is the chosen species for a JILA experiment to measure the electron electric dipole moment (eEDM). Detailed knowledge of the spectrum of HfF is crucial to prepare HfF⁺ in a state suitable for performing an eEDM measurement [1]. We investigated the near-infrared electronic spectrum of HfF using laser-induced fluorescence (LIF) of a supersonic molecular beam. We discovered eight unreported bands, and assign each of them unambiguously, four to vibrational bands belonging to the transition [13.8]0.5 &larr; X1.5, and four to vibrational bands belonging to the transition [14.2]1.5 &larr; X1.5. Additionally, we report an improved measurement of vibrational spacing of the ground state, as well as anharmonicity &omega;ₑxₑ.</p

    REMPI Spectroscopy of HfF

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    The spectrum of electronic states at 30000--33000 cm1^{-1} in hafnium fluoride has been studied using (1+1) resonance-enhanced multi-photon ionization (REMPI) and (1+1') REMPI. Six Ω=3/2\Omega' = 3/2 and ten Π1/2\Pi_{1/2} vibronic bands have been characterized. We report the molecular constants for these bands and estimate the electronic energies of the excited states using a correction derived from the observed isotope shifts. When either of two closely spaced Π1/2\Pi_{1/2} electronic states is used as an intermediate state to access autoionizing Rydberg levels, qualitatively distinct autoionization spectra are observed. The intermediate state-specificity of the autoionization spectra bodes well for the possibility of using a selected Π1/2\Pi_{1/2} state as an intermediate state to create ionic HfF+^+ in various selected quantum states, an important requirement for our electron electric dipole moment (eEDM) search in HfF+^+.Comment: 11 pages, 8 figures, 1 tabl

    Modeling the frequency response of microwave radiometers with QUCS

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    Characterization of the frequency response of coherent radiometric receivers is a key element in estimating the flux of astrophysical emissions, since the measured signal depends on the convolution of the source spectral emission with the instrument band shape. Laboratory Radio Frequency (RF) measurements of the instrument bandpass often require complex test setups and are subject to a number of systematic effects driven by thermal issues and impedance matching, particularly if cryogenic operation is involved. In this paper we present an approach to modeling radiometers bandpasses by integrating simulations and RF measurements of individual components. This method is based on QUCS (Quasi Universal Circuit Simulator), an open-source circuit simulator, which gives the flexibility of choosing among the available devices, implementing new analytical software models or using measured S-parameters. Therefore an independent estimate of the instrument bandpass is achieved using standard individual component measurements and validated analytical simulations. In order to automate the process of preparing input data, running simulations and exporting results we developed the Python package python-qucs and released it under GNU Public License. We discuss, as working cases, bandpass response modeling of the COFE and Planck Low Frequency Instrument (LFI) radiometers and compare results obtained with QUCS and with a commercial circuit simulator software. The main purpose of bandpass modeling in COFE is to optimize component matching, while in LFI they represent the best estimation of frequency response, since end-to-end measurements were strongly affected by systematic effects

    Postcolonial healing landscapes and mental health in a remote Indigenous community in subarctic Ontario, Canada

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    The concept of therapeutic landscape is concerned with a holistic, socio-ecological model of health, but most studies have attempted to explore land-health links from a Western perspective. On an Indigenous reserve in Northern Ontario, part of the Canadian subarctic, we explore the importance of spaces and places in creating postcolonial therapeutic landscapes to treat the wounds inflicted by colonialism. The aim of this research is to gain insight from views and experiences of First Nations residents living on reservations that are undergoing a process of regaining traditional spiritual beliefs and teachings to construct therapeutic spaces to face mental health problems caused by legal opioid analgesic abuse. This qualitative study used semi-structured interviews with Cree and Ojibwe participants to understand how they are reconnecting with earth, spirituality and traditional animist beliefs on their way to recovery. We find that practices such as taking part in ceremonies and ritual spaces, and seeking knowledge and advice from Elders assist with personal healing and enable Indigenous people to be physically and mentally healthy. Our research findings provide important insights into the relationship between space, healing and culture as determinants of health and well-being and document some key factors that contribute to substance abuse recovery.This work was supported by the Ministry of Education and Science (Spain) [I + D+i SEJ2005-09344/SOCI]; Social Sciences and Humanities Research Council (Canada) [I + D+i CURA/NORTHERN]

    Implementation and performance evaluation of an integrated specimen referral system in Burkina Faso using the national courier services (2020–2022)

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    IntroductionIn 2017, the Ministry of Health and Public Hygiene (MoH) of Burkina Faso designed and piloted a specimen transport system using the national courier services (La Poste BF) in 4 districts. Based on satisfactory performance indicators, the MoH set a vision aimed at scaling up this system to strengthen disease detection and surveillance of epidemic prone diseases across the country. This work describes the implementation process, performances, and lessons learned.MethodologyThis work describes the implementation process, performances, and lessons learned. Under the leadership of the Directorate of Population Health Protection within the MoH, a stepwise approach was used to bring together multiple partners across sectors to develop the first needed documents including a guide, an implementation plan, Standard Operating Procedures, and data collection tools. Then, the execution phase included equipment purchase, trainings, and consensus on a financing mechanism. Key indicators were defined to allow performance monitoringResultThe integrated biological specimen referral system (SITEB) was officially launched in January 2020 to transport human biological specimens of priority diseases including COVID-19 from district level to reference laboratories nationwide. As of December 31, 2022, La Poste BF transported 168,856 packages containing 206,314 specimens from all 13 regions. 99.66% of packages were delivered in &lt;24 h as required, and 99.68% of specimens were in good condition at reception. COVID-19 specimens represented respectively 18% and 63% of samples transported in 2020 and 2021.DiscussionThe political will combined with the experience gained during the pilot phase and the commitment and support from all stakeholders laid to the foundation of the effective implementation of this system. Collaboration between two government entities (MoH and Minister of Transport, Urban Mobility, and Road Safety) to benefit public health has led to reasonable pricing for sustainability. Although all documents integrate the “One Health“ approach, the system ensures the transport of only human samples for now. Despite security constraints, Burkina Faso has successfully set up a system using the national postal service to ensure the routine transport of specimens for all diseases under laboratory surveillance including laboratory tests for HIV and TB from the district level to reference laboratories nationwide. This system has also proved to be useful and efficient in managing public health emergency

    Financial Characteristics of Companies Audited by Large Audit Firms

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    Purpose “ The purpose of this paper is to examine how financial characteristics associated with the choice of a big audit firm with further investigation on the agency costs of free cash flows.Design/methodology/approach “ The sample used for this work includes industrial listed companies from Germany and France. To test our hypothesis, we used a number of logit models, extending the standard model selection audit firm, to include the variables of interest. Following previous work, our dependent dummy variable is Big4 or non-Big4.Findings “ We observed that most independent variables in the German companies show similar results to previous work, but we did not have the same results for the French industry. Moreover, our findings suggest that the total debt and dividends can be an important reason for determining the choice of a large audit firm, reducing agency costs of free cash flows.Research limitations/implications “ This study has some limitations on the measurements of the cost of the audit fees and also generates opportunities for additional searching.Originality/value “ The paper provides only one aspect to explain the relationship between the problems of agency costs of free cash flow and influence in choosing a large auditing firm, which stems from investors\u27 demand for higher quality audits

    Long-term thermal sensitivity of Earth’s tropical forests

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    The sensitivity of tropical forest carbon to climate is a key uncertainty in predicting global climate change. Although short-term drying and warming are known to affect forests, it is unknown if such effects translate into long-term responses. Here, we analyze 590 permanent plots measured across the tropics to derive the equilibrium climate controls on forest carbon. Maximum temperature is the most important predictor of aboveground biomass (−9.1 megagrams of carbon per hectare per degree Celsius), primarily by reducing woody productivity, and has a greater impact per °C in the hottest forests (>32.2°C). Our results nevertheless reveal greater thermal resilience than observations of short-term variation imply. To realize the long-term climate adaptation potential of tropical forests requires both protecting them and stabilizing Earth’s climate
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