Reflectarray antennas for dual polarization and broadband telecom satellite applications

A reflectarray antenna with improved performance is proposed to operate in dual-polarization and transmit-receive frequencies in Ku-band for broadcast satellite applications. The reflectarray element contains two orthogonal sets of four coplanar parallel dipoles printed on two surfaces, each set combining lateral and broadside coupling. A 40-cm prototype has been designed, manufactured, and tested. The lengths of the coupled dipoles in the reflectarray cells have been optimized to produce a collimated beam in dual polarization in the transmit and receive bands. The measured radiation patterns confirm the high performance of the antenna in terms of bandwidth (27%), low losses, and low levels of cross polarization. Some preliminary simulations at 11.95 GHz for a 1.2-m antenna with South American coverage are presented to show the potential of the proposed antenna for spaceborne antennas in Ku-band

Effective-periodicity effects in Fibonacci slot arrays

In this Letter, the transmission properties of a nonperiodic array of slots arranged in the form of a Fibonacci sequence are investigated. By arranging the slots in this manner, an additional periodicity can be utilized, resulting in corresponding resonance features in the transmitted signal. By investigating the transmission response of a perforated metallic sheet over a broad frequency range (6–40 GHz), it is shown that this simple one-dimensional chain supports two periodicities, one due to the regular periodic separation and one due to average spacing—which is related to the golden ratio. This response replicates the resonant behavior of a two-dimensional periodic array with a single nonperiodic array also creating new families of diffraction lobes in the far-field region.MCIN/AEI/10.13039/501100011033 PID2020-116739GB-I00EPSRC EP/R004781/1EPSRC EP/L015331/

Enhanced MoM for the analysis of multilayered periodic structures containing dipoles with application to the design of reflectarray antennas

The spectral domain Method of Moments (MoM) is customarily used in the analysis of multilayered periodic structures. In this paper a hybrid MoM is introduced for the analysis of multilayered periodic structures containing sets of dipoles at two metallization levels. In the hybrid MoM the matrix entries involving basis functions of dipoles at different metallization levels are computed in the spectral domain. However, the matrix entries involving basis functions at the same metallization level are computed in the spatial domain. The implemented hybrid MoM is applied to the design of multilayered reflectarray antennas made of dipoles under the local periodicity assumption. Thanks to the use of interpolated expressions for the periodic spatial Green's functions in terms of both coordinates and incidence angles, the CPU time required by the hybrid MoM in the design of the antennas is around twenty times faster than that required by the spectral domain MoM

Dual polarized reflectarray antenna to generate independent beams in Ku and Ka bands

This contribution describes the design of a printed reflectarray antenna for operating at Ku and Ka frequency bands. The reflectarray has been designed to produce a focused beam at 11.95 and 20 GHz for both Horizontal and Vertical polarizations. The antenna is illuminated by a corrugated horn, modelled as a cos-q function with different q-factor values at 11.95 and 20 GHz. The periodic element is made of two stacked sets of dipoles, each of one comprising two orthogonal subsets of coplanar parallel dipoles, whose lengths are adjusted to focus the beam at each polarization and frequency band. The dimensions of all dipoles are calculated for a circular reflectarray of 33×33 elements (33-cm sided), using a MoM-SD based analysis routine and local periodicity approach. The simulated radiation patterns of the antenna show a gain of 30.7 dBi at 11.95 GHz and 34.2 dBi at 20 GHz, with side-lobe levels close to -21 dB

Cross-polar reduction in reflectarray antennas by means of element rotation

A cross-polar reduction technique for dual polarization reflectarray antennas is proposed. This technique is based on the determination of the rotation angle of each reflectarray element that minimizes the cross-polar components of the electric and magnetic fields reflected by that particular element in each polarization under local periodicity assumption. The results obtained with the cross-polar reduction technique have been validated by comparison with results provided by the commercial software CST. The technique has been applied to the reduction of the cross-polarization radiated by a dual polarization transmit-receive reflectarray antenna. The results obtained after cross-polar reduction show minimum values of cross-polar discrimination of 35 dB for one polarization and 40 dB for the orthogonal polarization, both in the Tx and Rx-bands

A high concentration of TGF-β correlates with opportunistic infection in liver and kidney transplantation

Transforming growth factor-β (TGF-β) has been associated with numerous human infections, but its role in the occurrence of opportunistic infection (OI) after solid organ transplantation remains unexplored. This study aimed to assess the utility of the TGF-β following in vitro stimulation of whole peripheral blood (WPB) as a surrogate biomarker of post-transplant OI in a cohort of liver and kidney recipients. Thirty liver and thirty-one kidney transplant recipients were recruited to be prospectively monitored for one-year post-transplantation. Enzyme-linked immunosorbent assay (ELISA) was performed to calculate IFN-γ, IL-17, IL-10 and TGF-β concentration in the supernatant from the activated WPB. Recipients showed higher TGF-β concentrations compared to IFN-γ, IL-17, IL-10 at baseline, although these differences were not significant between INF and NoINF. However, recipients who developed an OI within the first sixth months had a higher concentration of TGF-β than those without OI. A concentration of TGF-β > 363.25 pg/ml in liver and TGF-β > 808.51 pg/ml in kidney recipients were able to stratify patients at high risk of OI with a sensitivity and specificity above 70% in both types of solid organ transplantations. TGF-β could provide valuable information for the management of liver and kidney recipients at risk of post-transplant infection.Our work was possible thanks to the support and funding obtained from the “Instituto de Salud Carlos III (ISCIII)”, Spanish Ministry of Health (Grant Number PI15/01370 and P19/01194); and co-funding by the European Union from the European Regional Development Fund (ERDF) with the principle of “A manner to build Europe”

The economic geography of the meso-global spaces: integrating multinationals and clusters at the local-global level

This is an author's accepted manuscript of an article published in: “European Planning Studies"; Volume 21, Issue 7, 2013; copyright Taylor & Francis; available online at: http://dx.doi.org/10.1080/09654313.2013.733853[EN] The local global phenomenon literature is fragmented between the fields of international business and economic geography (EG). In the case of the latter, the literature, produced within the global production networks (GPNs) and global value chain frameworks, does not address the central role of firms, especially multinationals which co-locate and connect territories along GPNs. This paper develops a cross-field conceptual integration in order to enrich the EG perspective, using qualitative research methodology to test the framework. The results have important implications for scholars and policymakers.We are very thankful to the “Ministry of Economics” funding ECO2010:17318 and “Generalitat Valenciana” for its support in visiting the London School of Economics and Political Science (BEST 2011 grants)Hervás Oliver, JL.; Boix Domenech, R. (2012). The economic geography of the meso-global spaces: integrating multinationals and clusters at the local-global level. European Planning Studies. 21(7):1064-1080. https://doi.org/10.1080/09654313.2013.733853S1064108021

Corrigendum to ‘a horizon scan exercise for aquatic invasive alien species in Iberian inland waters’

info:eu-repo/semantics/publishedVersio

Effectiveness of Fosfomycin for the Treatment of Multidrug-Resistant Escherichia coli Bacteremic Urinary Tract Infections

IMPORTANCE The consumption of broad-spectrum drugs has increased as a consequence of the spread of multidrug-resistant (MDR) Escherichia coli. Finding alternatives for these infections is critical, for which some neglected drugs may be an option. OBJECTIVE To determine whether fosfomycin is noninferior to ceftriaxone or meropenem in the targeted treatment of bacteremic urinary tract infections (bUTIs) due to MDR E coli. DESIGN, SETTING, AND PARTICIPANTS This multicenter, randomized, pragmatic, open clinical trial was conducted at 22 Spanish hospitals from June 2014 to December 2018. Eligible participants were adult patients with bacteremic urinary tract infections due to MDR E coli; 161 of 1578 screened patients were randomized and followed up for 60 days. Data were analyzed in May 2021. INTERVENTIONS Patients were randomized 1 to 1 to receive intravenous fosfomycin disodium at 4 g every 6 hours (70 participants) or a comparator (ceftriaxone or meropenem if resistant; 73 participants) with the option to switch to oral fosfomycin trometamol for the fosfomycin group or an active oral drug or pa renteral ertapenem for the comparator group after 4 days. MAIN OUTCOMES AND MEASURES The primary outcome was clinical and microbiological cure (CMC) 5 to 7 days after finalization of treatment; a noninferiority margin of 7% was considered. RESULTS Among 143 patients in the modified intention-to-treat population (median [IQR] age, 72 [62-81] years; 73 [51.0%] women), 48 of 70 patients (68.6%) treated with fosfomycin and 57 of 73 patients (78.1%) treated with comparators reached CMC (risk difference, -9.4 percentage points; 1-sided 95% CI, -21.5 to infinity percentage points; P = .10). While clinical or microbiological failure occurred among 10 patients (14.3%) treated with fosfomycin and 14 patients (19.7%) treated with comparators (risk difference, -5.4 percentage points; 1-sided 95% CI. -infinity to 4.9; percentage points; P = .19), an increased rate of adverse event-related discontinuations occurred with fosfomycin vs comparators (6 discontinuations [8.5%] vs 0 discontinuations; P = .006). In an exploratory analysis among a subset of 38 patients who underwent rectal colonization studies, patients treated with fosfomycin acquired a new ceftriaxone-resistant or meropenem-resistant gram-negative bacteria at a decreased rate compared with patients treated with comparators (0 of 21 patients vs 4 of 17 patients [23.5%]; 1-sided P = .01). CONCLUSIONS AND RELEVANCE This study found that fosfomycin did not demonstrate noninferiority to comparators as targeted treatment of bUTI from MDR E coli; this was due to an increased rate of adverse event-related discontinuations. This finding suggests that fosfomycin may be considered for selected patients with these infections