Omnidirectional conformal patch antenna at S-band with 3D printed technology

A conformal patch array antenna with omnidirectional pattern in the azimuth plane at Sband is presented. A theoretical study of the generated ripple in the omnidirectional radiation pattern according to the number of faces that conform the array has been computed. A six-faced regular prism 3D structure has been chosen following a maximum 3 dB ripple criteria in the omnidirectional radiation pattern. A rectangular microstrip patch fed by a microstrip line has been designed as single radiating element. An equal power divider has been designed as feeding network in microstrip technology to feed each radiating element. Several prototypes have been manufactured and measured to validate the theoretical and simulated results. The entire conformal array has been assembled on a hexagonal regular prism manufactured in PolyLactic Acid (PLA) material using a 3D printer. In spite of the complexity of the proposed antenna structure, the used manufacturing processes, such as microstrip and 3D printing, allows to perform a low cost, low weight and compact final antenna. A higher radiated field ripple than the expected one is generated due to small deviations between experimental and theoretical critical parameters such as the feeding network performance or the 3 dB beam-width of the single element radiation pattern. A maximum ripple value of 4 dB has been experimentally obtained in the omnidirectional radiating pattern.This work has been supported by the Spanish Government, Ref. TEC2013-47106-C3-2-R (Project TECOAMP) and Madrid Region Government, Ref. S2013/ICE-3000 (Project SPADERADAR)

Waveguide manufacturing technologies for next-generation millimeter-wave antennas

Some recent waveguide-based antennas are presented in this paper, designed for the next generation of communication systems operating at the millimeter-wave band. The presented prototypes have been conceived to be manufactured using different state-of-the-art techniques, involving subtractive and additive approaches. All the designs have used the latest developments in the field of manufacturing to guarantee the required accuracy for operation at millimeter-wave frequencies, where tolerances are extremely tight. Different designs will be presented, including a monopulse antenna combining a comparator network, a mode converter, and a spline profile horn; a tunable phase shifter that is integrated into an array to implement reconfigurability of the main lobe direction; and a conformal array antenna. These prototypes were manufactured by diverse approaches taking into account the waveguide configuration, combining parts with high-precision milling, electrical discharge machining, direct metal laser sintering, or stereolithography with spray metallization, showing very competitive performances at the millimeter-wave band till 40 GHzThis work was supported by the Spanish Government under Grant TEC2016-76070- C3-1/2-R (ADDMATE); in part under Grant PID2020-116968RB-C32/33 (DEWICOM), Agencia Estatal de Investigación MCIN/AEI/10.13039/501100011033, Fondo Europeo de Desarrollo Regional: AEI/FEDER, UE. This work was also partially supported under Grant S2013/ICE3000 (SPADERADARCM), Madrid Regional Governmen

Permanent control of HIV-1 pathogenesis in exceptional elite controllers: a model of spontaneous cure

Elite controllers (EC) represent a small subset of HIV-1-infected people that spontaneously control viral replication. However, natural virological suppression and absence of immune dysfunction are not always long-term sustained. We define exceptional EC (EEC) as HIV-1 subjects who maintain the EC characteristics without disease progression for more than 25 years. We analyzed three EEC, diagnosed between 1988 and 1992, who never showed signs of clinical disease progression in absence of any antiretroviral treatment. A comprehensive clinical, virological, and immunological study was performed. The individuals simultaneously exhibited ≥3 described host protective alleles, low levels of total HIV-1 DNA (0.50). Inflammation levels of EEC were similar to HIV-1 negative donors. Remarkably, they showed an exceptional lack of viral evolution and 8-fold lower genetic diversity (<0.01 s/n) in env gene than other EC. We postulate that these EEC represent cases of spontaneous functional HIV-1 cure. A non-functional and non-genetically evolving viral reservoir along with an HIV-1-specific immune response seems to be key for the spontaneous functional cure.Work in Centro Nacional de Microbiologia (ISCIII) was supported by grants SAF (2016–77894-R) from Ministerio de Economia y Competitividad (MINECO) (Spain) and Fondo de Investigación Sanitaria (FIS)-Instituto de Salud CarlosIII, grant FIS (PI 13/02269, ISCIII) and in part by the RIS-RETIC grants RD12/0017/0028 and RD16CIII/0002/0005 funded by the ISCIII-FEDER. MP has a contract of RIS-RETIC RD16CIII/0002/0005. This work was supported by grants from the MINECO, FIS-Instituto de Salud CarlosIII, Fondos Europeos para el Desarrollo Regional, FEDER, grant numbers PI16/00684, PI19/01127, CPII014/00025 to ER-M. and FI14/00431 to LT-D.; the Gilead Fellowship Program (grant numbers GLD17/00299); the Red de Investigación en Sida (grant number RD16/0025/0020). ER-M. is supported by Consejería de Salud y Bienestar Social of Junta de Andalucía through the Nicolás Monardes Program (C-0032/17). Research in VS-M group was supported by Fondo de Investigación Sanitaria (FIS)-Instituto de Salud CarlosIII, grant FIS (PI 17CIII/00049). Grifols partially supported work in the AIDS Research Institute IrsiCaixa. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.S

Study protocol and rationale of the “Cogniaction project” a cross-sectional and randomized controlled trial about physical activity, brain health, cognition, and educational achievement in schoolchildren

Background: Education and health are crucial topics for public policies as both largely determine the future wellbeing of the society. Currently, several studies recognize that physical activity (PA) benefits brain health in children. However, most of these studies have not been carried out in developing countries or lack the transference into the education field. The Cogni-Action Project is divided into two stages, a cross-sectional study and a crossover-randomized trial. The aim of the first part is to establish the associations of PA, sedentarism, and physical fitness with brain structure and function, cognitive performance and academic achievement in Chilean schoolchildren (10–13 years-old). The aim of the second part is to determinate the acute effects of three PA protocols on neuroelectric indices during a working memory and a reading task. Methods: PA and sedentarism will be self-reported and objectively-assessed with accelerometers in a representative subsample, whilst physical fitness will be evaluated through the ALPHA fitness test battery. Brain structure and function will be assessed by magnetic resonance imaging (MRI) in a randomized subsample. Cognitive performance will be assessed through the NeuroCognitive Performance Test, and academic achievement by school grades. In the second part 32 adolescents (12–13 year-old) will be cross-over randomized to these condition (i) “Moderate-Intensity Continuous Training” (MICT), (ii) “Cooperative High-Intensity Interval Training” (C-HIIT), and (iii) Sedentary condition. Neuroelectric indices will be measures by electroencephalogram (EEG) and eye-tracking, working memory by n-back task and reading comprehension by a reading task

The Mediation Effect of Self-Report Physical Activity Patterns in the Relationship between Educational Level and Cognitive Impairment in Elderly: A Cross-Sectional Analysis of Chilean Health National Survey 2016-2017

The aims of this cross-sectional study were (i) to determine the association of educational level attained with cognitive impairment and (ii) to investigate the mediating effect of different self-report physical activity (PA) patterns in a large sample of older Chileans. A sample of 1571 older adults from the National Chilean Survey (2016-2017) was included. The educational level attained, PA levels, mode of commuting, sedentary time, and leisure-time PA were self-reported through validated questionnaires. Cognitive impairment was determined by Mini-Mental State Examination (modified version). Association between educational level attained and cognitive impairment was examined using logistic regression models. Counterfactual mediation models were used to test the mediating effect of self-reported PA patterns. A lower educational level was consistently associated with higher odds of cognitive impairment (OR range 2.846 to 2.266, all p < 0.001), while leisure-time PA was the only PA pattern that partially mediated this association (proportion mediated 8.0%). In conclusion, leisure-time PA was the solely PA pattern that partially mediated the association between the educational level and cognitive impairment. The rest self-reported PA patterns did not modify this association.P.S.-U. was supported by a grant from ANID/BECAS Chile/72180543. J.P.-D. is part of the University of Granada, Plan Propio de Investigación 2016, Excellence actions: Units of Excellence; Unit of Excellence on Exercise and Health (UCEES).Ye

Comparison of seven prognostic tools to identify low-risk pulmonary embolism in patients aged <50 years

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Monitoring the Morphology of M87* in 2009–2017 with the Event Horizon Telescope

The Event Horizon Telescope (EHT) has recently delivered the first resolved images of M87*, the supermassive black hole in the center of the M87 galaxy. These images were produced using 230 GHz observations performed in 2017 April. Additional observations are required to investigate the persistence of the primary image feature—a ring with azimuthal brightness asymmetry—and to quantify the image variability on event horizon scales. To address this need, we analyze M87* data collected with prototype EHT arrays in 2009, 2011, 2012, and 2013. While these observations do not contain enough information to produce images, they are sufficient to constrain simple geometric models. We develop a modeling approach based on the framework utilized for the 2017 EHT data analysis and validate our procedures using synthetic data. Applying the same approach to the observational data sets, we find the M87* morphology in 2009–2017 to be consistent with a persistent asymmetric ring of ~40 μas diameter. The position angle of the peak intensity varies in time. In particular, we find a significant difference between the position angle measured in 2013 and 2017. These variations are in broad agreement with predictions of a subset of general relativistic magnetohydrodynamic simulations. We show that quantifying the variability across multiple observational epochs has the potential to constrain the physical properties of the source, such as the accretion state or the black hole spin

THEMIS: A Parameter Estimation Framework for the Event Horizon Telescope

The Event Horizon Telescope (EHT) provides the unprecedented ability to directly resolve the structure and dynamics of black hole emission regions on scales smaller than their horizons. This has the potential to critically probe the mechanisms by which black holes accrete and launch outflows, and the structure of supermassive black hole spacetimes. However, accessing this information is a formidable analysis challenge for two reasons. First, the EHT natively produces a variety of data types that encode information about the image structure in nontrivial ways; these are subject to a variety of systematic effects associated with very long baseline interferometry and are supplemented by a wide variety of auxiliary data on the primary EHT targets from decades of other observations. Second, models of the emission regions and their interaction with the black hole are complex, highly uncertain, and computationally expensive to construct. As a result, the scientific utilization of EHT observations requires a flexible, extensible, and powerful analysis framework. We present such a framework, Themis, which defines a set of interfaces between models, data, and sampling algorithms that facilitates future development. We describe the design and currently existing components of Themis, how Themis has been validated thus far, and present additional analyses made possible by Themis that illustrate its capabilities. Importantly, we demonstrate that Themis is able to reproduce prior EHT analyses, extend these, and do so in a computationally efficient manner that can efficiently exploit modern high-performance computing facilities. Themis has already been used extensively in the scientific analysis and interpretation of the first EHT observations of M87

SYMBA: An end-to-end VLBI synthetic data generation pipeline: Simulating Event Horizon Telescope observations of M 87

Context. Realistic synthetic observations of theoretical source models are essential for our understanding of real observational data. In using synthetic data, one can verify the extent to which source parameters can be recovered and evaluate how various data corruption effects can be calibrated. These studies are the most important when proposing observations of new sources, in the characterization of the capabilities of new or upgraded instruments, and when verifying model-based theoretical predictions in a direct comparison with observational data. Aims. We present the SYnthetic Measurement creator for long Baseline Arrays (SYMBA), a novel synthetic data generation pipeline for Very Long Baseline Interferometry (VLBI) observations. SYMBA takes into account several realistic atmospheric, instrumental, and calibration effects. Methods. We used SYMBA to create synthetic observations for the Event Horizon Telescope (EHT), a millimetre VLBI array, which has recently captured the first image of a black hole shadow. After testing SYMBA with simple source and corruption models, we study the importance of including all corruption and calibration effects, compared to the addition of thermal noise only. Using synthetic data based on two example general relativistic magnetohydrodynamics (GRMHD) model images of M 87, we performed case studies to assess the image quality that can be obtained with the current and future EHT array for different weather conditions. Results. Our synthetic observations show that the effects of atmospheric and instrumental corruptions on the measured visibilities are significant. Despite these effects, we demonstrate how the overall structure of our GRMHD source models can be recovered robustly with the EHT2017 array after performing calibration steps, which include fringe fitting, a priori amplitude and network calibration, and self-calibration. With the planned addition of new stations to the EHT array in the coming years, images could be reconstructed with higher angular resolution and dynamic range. In our case study, these improvements allowed for a distinction between a thermal and a non-thermal GRMHD model based on salient features in reconstructed images

A Universal Power-law Prescription for Variability from Synthetic Images of Black Hole Accretion Flows

We present a framework for characterizing the spatiotemporal power spectrum of the variability expected from the horizon-scale emission structure around supermassive black holes, and we apply this framework to a library of general relativistic magnetohydrodynamic (GRMHD) simulations and associated general relativistic ray-traced images relevant for Event Horizon Telescope (EHT) observations of Sgr A*. We find that the variability power spectrum is generically a red-noise process in both the temporal and spatial dimensions, with the peak in power occurring on the longest timescales and largest spatial scales. When both the time-averaged source structure and the spatially integrated light-curve variability are removed, the residual power spectrum exhibits a universal broken power-law behavior. On small spatial frequencies, the residual power spectrum rises as the square of the spatial frequency and is proportional to the variance in the centroid of emission. Beyond some peak in variability power, the residual power spectrum falls as that of the time-averaged source structure, which is similar across simulations; this behavior can be naturally explained if the variability arises from a multiplicative random field that has a steeper high-frequency power-law index than that of the time-averaged source structure. We briefly explore the ability of power spectral variability studies to constrain physical parameters relevant for the GRMHD simulations, which can be scaled to provide predictions for black holes in a range of systems in the optically thin regime. We present specific expectations for the behavior of the M87* and Sgr A* accretion flows as observed by the EHT