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Accurate estimations of actual crop evapotranspiration are of utmost importance to evaluate crop water requirements and to optimize water use efficiency. At this aim, coupling simple agro-hydrological models, such as the well-known FAO-56 model, with remote observations of the land surface could represent an easy-to-use tool to identify biophysical parameters of vegetation, such as the crop coefficient Kc under the actual field conditions and to estimate actual crop evapotranspiration. This paper intends, therefore, to propose an operational procedure to evaluate the spatio-temporal variability of Kc in a citrus orchard characterized by the sporadic presence of ground weeds, based on micro-meteorological measurements collected on-ground and vegetation indices (VIs) retrieved by the Sentinel-2 sensors. A non-linear Kc(VIs) relationship was identified after assuming that the sum of two VIs, such as the normalized difference vegetation index, NDVI, and the normalized difference water index, NDWI, is suitable to represent the spatio-temporal dynamics of the investigated environment, characterized by sparse vegetation and the sporadic presence of spontaneous but transpiring soil weeds, typical of winter seasons and/or periods following events wetting the soil surface. The Kc values obtained in each cell of the Sentinel-2 grid (10 m) were then used as input of the spatially distributed FAO-56 model to estimate the variability of actual evapotranspiration (ETa) and the other terms of water balance. The performance of the proposed procedure was finally evaluated by comparing the estimated average soil water content and actual crop evapotranspiration with the corresponding ones measured on-ground. The application of the FAO-56 model indicated that the estimated ETa were characterized by root-mean-square-error, RMSE, and mean bias-error, MBE, of 0.48 and -0.13 mm d−1 respectively, while the estimated soil water contents, SWC, were characterized by RMSE equal to 0.01 cm3 cm−3 and the absence of bias, then confirming that the suggested procedure can produce highly accurate results in terms of dynamics of soil water content and actual crop evapotranspiration under the investigated field conditions. [ABSTRACT FROM AUTHOR]

This research aimed at assessing four different methodologies to estimate daily irrigation depth, based on the monitoring of soil water status (soil water content sensors, SWS, and tensiometers, TS) and atmospheric evaporative demand (weighing lysimeter, WL, and Piché evaporimeter, PE), of green bell pepper (Capsicum annum L.) cultivated in a greenhouse. Furthermore, two different strategies to apply the daily irrigation depths, i.e., single watering (at 8:00 a.m.) or split into two equal applications (at 8:00 a.m. and at 4:30 p.m.), were also investigated. The experiment was conducted in a completely randomized design and according to a 4 × 2 factorial scheme with eight replications. The statistical analysis showed that total water volume (TWV), commercial yield, and crop water use efficiency (WUE) were influenced by the method used to estimate crop water requirement and the irrigation strategies. The TWV applied during the whole crop cycle was 562.7 mm, 731.2 mm, 769.4 mm, and 843.1 mm for treatments with WL, PE, SWS, and TS, respectively. The highest commercial yield was obtained in treatments in which the highest irrigation depth was applied (SWS, 11.55 t ha−1, and TS, 10.09 t ha−1). On the other hand, relatively higher WUE was achieved in treatments managed with SWS (1.63 kg m−3) and WL (1.55 kg m−3). Splitting the estimated daily irrigation depth into two applications promoted the commercial productivity and WUE (9.24 t ha−1 and 1.60 kg m−3) compared to the single application (7.06 t ha−1 and 1.22 kg m−3). Splitting the daily irrigation depth is, therefore, a promising strategy to increase WUE for green bell pepper crops in protected environments. [ABSTRACT FROM AUTHOR]

Receiver ghosts attenuate marine seismic reflection data at harmonic frequencies that depend on the propagation angle and the streamer depth below the sea surface. The resulting loss of bandwidth is one of the major factors hampering seismic resolution. In near-surface and legacy multi-channel data, receivers depth is often unknown and may vary significantly both along the streamer length and during the survey, making frequency–slowness deghosting techniques unsuitable. In this work, we present a method for the attenuation of receiver ghost reflections in data with an arbitrary streamer depth profile varying during the survey. For each trace, a different deghosting operator is estimated and applied at different two-way-time windows, in order to account for depth-dependent changes in reflection angles. The ghost null frequencies are picked on the time-varying power spectrum via an automatic algorithm, guided by a user-dependent a priori function, and optimised to respect the harmonics’ periodicity. The power of the inverse filter is adjusted by adaptively damping abnormal amplitudes in the deghosted spectra. The algorithm is applied to high-resolution (GI-gun, 20–400 Hz) and ultra-high-resolution (Sparker, 0.2–3.0 kHz) multi-channel datasets, yielding an excellent bandwidth recovery and gain in resolution in the final stacks. Limited computing time and straightforward application make the method widely applicable and cost-effective. [ABSTRACT FROM AUTHOR]

The objective of this study is to assess the effectiveness and safety of TNF-α blockers in a group of early psoriatic arthritis (PsA) patients with an unsatisfactory response to previous conventional treatment consecutively enrolled in five Italian centres. A 24-week open-label trial was carried out in consecutive early PsA patients classified according to the CASPAR criteria, with unsatisfactory response to previous treatments and with a DAS28 threshold as ≥3.2, seen at the outpatient clinics of each centre. Exclusion criteria were previous usage of TNF-α blockers and a disease duration >12 months. The choice of any of the three TNF-α blockers was decided by the expert's opinion, without any restriction. Effectiveness was considered as an improvement of DAS28 at 12 and 24 weeks of treatment. Secondary endpoints were an improvement of TJC, SWJ, HAQ score and PASI score. Changes from baseline to the 12- and 24-week follow-up assessments were analysed using the Wilcoxon paired sign rank test. Twenty-nine patients (14 males, 15 females, median age 37 years, range 20-65 years) were enrolled. A statistical improvement of the DAS28 was observed at 12 and 24 weeks from baseline ( p < 0.001). Secondary endpoints also confirmed the effectiveness of the TNF-α blockers in the treatment of early PsA. No severe adverse events were observed during the treatment period, and no patient withdrew from the medications. This study suggests that the TNF-α blockers can be effective in the management of early PsA. Further controlled studies will provide more data on this challenging topic. [ABSTRACT FROM AUTHOR]