A millimeter-wave Bessel beam launcher through the excitation of higher-order leaky modes

International audienceWe present a Bessel beam launcher based on a radial leaky-wave antenna operating at millimeter waves. With respect to a design method proposed by one of the Authors in a lower frequency range, a new approach is chosen here, as an alternative to a simple scaling of all the geometrical parameters. In order to avoid inacceptable levels of losses and possible fabrication issues due to an extremely thin substrate, our design is based on the suitable excitation of a higher-order leaky mode. Closed-form equations are derived in order to simplify the design, providing reliable values for the physical parameters once the near-field characteristics are assigned. Simulated results are shown to validate the proposed procedure

Does corruption influence the self-restraint attitude of women-led SMEs towards bank lending?

In this article we address the question of whether the perceived level of corruption in a country may influence women’s inclination in self-refraining from applying for bank loans. Using a sample of 60,058 observations—drawn from the European Central Bank- Survey on the Access to Finance of Enterprises (ECB-SAFE)—related to small- and medium- sized enterprises (SMEs) chartered in 11 Euro-area countries during the period 2009–2014, we first investigate whether female-led businesses are more likely, than male-led ones, to refrain from applying for bank credit. Finally, we assess whether corruption actually matters in the women’s decision not to relying on the bank-lending channel. Our results—robust to various model specifications—highlight that women-led SMEs face a higher probability to self-refrain from applying for loans vis-à-vis their male counterparts. In addition, although corruption appears strongly correlated to the self-restraint attitudes of firms, our empirical analysis reveals that women-led SMEs generally tend to refrain from applying for loans, more than men, regardless of the quality of the surrounding environment

Computation of layered mixed potentials for the accurate and efficient analysis of periodic printed structures

International audienceOriginal acceleration procedures are proposed for the efficient calculation of the vertical components of the dyadic and scalar mixed-potential layered-media periodic Green's functions for various types of periodic structures. The extraction of suitable asymptotic terms, i.e., quasi-static images, is performed in order to speed up the convergence of the relevant spectral series. The extracted terms can be expressed as potentials for array of half-plane and half-line sources, depending on the type of the considered periodic Green's function. The relevant numerical results show the remarkable improvements in the efficiency of the approach

A comparative study of mechanical resistance of two reciprocating files

To evaluate the cyclic fatigue resistance of two different Nickel-Titanium instruments, Reziflow (Komet, Brasseler GmbH & Co., Lemgo, Germany) and WaveOne Gold (Dentsply Maillefer, Ballaigues, Switzerland). Two groups of 20 different NiTi endodontic instruments of identical tip size of 0.25 mm were tested; Reziflow and Wave-One Gold primary. Cyclic fatigue testing was performed in a stainless steel simulated root canal manufactured by reproducing the instrument?s size and taper. A simulated root canal with a 90 degrees angle of curvature and 5 mm radius of curvature was constructed for the instruments tested. The centre of the curvature was 5 mm from the tip of the instrument and the curved segment of the canal was approximately 5 mm in length. Both the instruments were used in the same preset program specific for the WaveOne instruments. Each instrument was rotated until fracture occurred and the time to fracture (TtF) and the length of the fractured fragment were recorded. Means and standard deviations of TtF and fragment length were calculated and data were subjected to statical analysis (P0.05) in the mean length of the fractured fragments between the instruments. Rezifllow instruments were associated with a significantly higher cyclic fatigue resistance than WaveOne Gold instruments

Benchmarking open source and paid services for speech to text: an analysis of quality and input variety

IntroductionSpeech to text (STT) technology has seen increased usage in recent years for automating transcription of spoken language. To choose the most suitable tool for a given task, it is essential to evaluate the performance and quality of both open source and paid STT services.MethodsIn this paper, we conduct a benchmarking study of open source and paid STT services, with a specific focus on assessing their performance concerning the variety of input text. We utilizes ix datasets obtained from diverse sources, including interviews, lectures, and speeches, as input for the STT tools. The evaluation of the instruments employs the Word Error Rate (WER), a standard metric for STT evaluation.ResultsOur analysis of the results demonstrates significant variations in the performance of the STT tools based on the input text. Certain tools exhibit superior performance on specific types of audio samples compared to others. Our study provides insights into STT tool performance when handling substantial data volumes, as well as the challenges and opportunities posed by the multimedia nature of the data.DiscussionAlthough paid services generally demonstrate better accuracy and speed compared to open source alternatives, their performance remains dependent on the input text. The study highlights the need for considering specific requirements and characteristics of the audio samples when selecting an appropriate STT tool

Analysis of limited-diffractive and limited-dispersive X-waves generated by finite radial waveguides

International audienceIn this work, we analyze the spatial and temporal features of electromagnetic X-waves propagating in free space and generated by planar radiating apertures. The performance of ideal X-waves is discussed and compared to practical cases where the important effects related to the finiteness of the radiating aperture and the wavenumber dispersion are taken into account. In particular, a practical device consisting of a radial waveguide loaded with radiating slots aligned along a spiral path is considered for the practical case in the millimeter-wave range. A common mathematical framework is defined for a precise comparison of the spatiotemporal properties and focusing capabilities of the generated X-wave. It is clearly shown that the fractional bandwidth of the radiating aperture has a key role in the longitudinal confinement of an X-wave in both ideal and practical cases. In addition, the finiteness of the radiating aperture as well as the wavenumber dispersion clearly affect both the transverse and the longitudinal profiles of the generated radiation as it travels beyond the depth-of-field of the generated X-wave. Nevertheless, the spatiotemporal properties of the X-wave are preserved even in this "dispersive-finite" case within a defined region and duration related to the nondiffractive range and fractional bandwidth of the spectral components of the generated X-wave. The proposed analysis may open new perspectives for the efficient generation of X-waves over finite radiating apertures at millimeter waves where the dispersive behavior of realistic devices is no longer negligible. Published by AIP Publishing

Geodetic model of the 2016 Central Italy earthquake sequence inferred from InSAR and GPS data

We investigate a large geodetic data set of interferometric synthetic aperture radar (InSAR)and GPS measurements to determine the source parameters for the three main shocks of the 2016Central Italy earthquake sequence on 24 August and 26 and 30 October (Mw6.1, 5.9, and 6.5,respectively). Our preferred model is consistent with the activation of four main coseismic asperitiesbelonging to the SW dipping normal fault system associated with the Mount Gorzano-Mount Vettore-Mount Bove alignment. Additional slip, equivalent to aMw~ 6.1–6.2 earthquake, on a secondary (1) NEdipping antithetic fault and/or (2) on a WNW dipping low-angle fault in the hanging wall of the mainsystem is required to better reproduce the complex deformation pattern associated with the greatestseismic event (theMw6.5 earthquake). The recognition of ancillary faults involved in the sequencesuggests a complex interaction in the activated crustal volume between the main normal faults and thesecondary structures and a partitioning of strain releas

Nutritional status and quality of life in adults undergoing allogeneic hematopoietic stem cell transplantation

Although the effects of malnutrition on morbidity and mortality in adult patients undergoing allogeneic hematopoietic stem cell transplantation are clear, the relationship with quality of life (QOL) is less clear. The purpose of this study was to assess the relationship between malnutrition and QOL. A prospective observational study was conducted in 36 adult patients undergoing allogeneic hematopoietic stem cell transplantation. Adapted criteria of the Global Leadership Initiative on malnutrition have been used for the diagnosis of malnutrition in clinical settings. A cancer linear analog scale was used to assess QOL. Overall QOL at 14 days after allogeneic hematopoietic stem cell transplantation was 37.1 (95% CI 2.9–45.39) in patients without severe malnutrition, versus 16.0 (95% CI − 6.6 to 38.6) in patients with severe malnutrition (p = 0.05). At discharge, it was 48.0 (95% CI 38.4–57.6) versus 34.0 (95% CI 4.1–63.9) (p = 0.27). The results of our study suggest that patients with severe malnutrition at discharge tend to have worse QOL. A larger cohort of patients is required to confirm this hypothesis

Unexpected impairment of INa underpins reentrant arrhythmias in a knock-in swine model of Timothy syndrome

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Five carbon- and nitrogen-bearing species in a hot giant planet's atmosphere

The atmospheres of gaseous giant exoplanets orbiting close to their parent stars (hot Jupiters) have been probed for nearly two decades. They allow us to investigate the chemical and physical properties of planetary atmospheres under extreme irradiation conditions. Previous observations of hot Jupiters as they transit in front of their host stars have revealed the frequent presence of water vapour and carbon monoxide in their atmospheres; this has been studied in terms of scaled solar composition under the usual assumption of chemical equilibrium. Both molecules as well as hydrogen cyanide were found in the atmosphere of HD 209458b, a well studied hot Jupiter (with equilibrium temperature around 1,500 kelvin), whereas ammonia was tentatively detected there and subsequently refuted. Here we report observations of HD 209458b that indicate the presence of water (H2O), carbon monoxide (CO), hydrogen cyanide (HCN), methane (CH4), ammonia (NH3) and acetylene (C2H2), with statistical significance of 5.3 to 9.9 standard deviations per molecule. Atmospheric models in radiative and chemical equilibrium that account for the detected species indicate a carbon-rich chemistry with a carbon-to-oxygen ratio close to or greater than 1, higher than the solar value (0.55). According to existing models relating the atmospheric chemistry to planet formation and migration scenarios, this would suggest that HD 209458b formed far from its present location and subsequently migrated inwards. Other hot Jupiters may also show a richer chemistry than has been previously found, which would bring into question the frequently made assumption that they have solar-like and oxygen-rich compositions.Comment: As part of the Springer Nature Content Sharing Initiative, it is possible to access a view-only version of this paper by using the following SharedIt link: https://rdcu.be/cifr