RESUMO
The Central European GNSS Research Network (CEGRN) collects GNSS data since 1994 from contributors which today include 42 Institutions in 33 Countries. CEGRN returns a dataset of coordinates and velocities computed according to international standards and the most recent processing procedures and recommendations. We provide a dataset of 1229 positions and velocities resulting from 3 or more repetitions of coordinate measurements of each site over 4 or more years. The velocity data result from a combination of eight multiyear, partially overlapping networks, using 234 stations of class A of the European Permanent Network (EPN) for alignment to the 'European Fixed' ETRF2000 Reference Frame. The rms (root mean square) of the 8 individual contributions to the combined solution, after a 7 - parameter Helmert transformation, is less than 5 mm in the observation period 1996-2017. This combined CEGRN network maintains the origin coincident with that of the ETRF2000 reference frame to within 1.8 mm rms for the entire period of analysis. The mean positions and velocities of common EPN Class A and CEGRN stations differ by 0.0 ± 1.1, 0.5 ± 1.0 and 0.1 ± 2.7 mm for the coordinates and 0.06 ± 0.13, -0.07 ± 0.12, 0.38 ± 0.28 mm/yr for the velocities respectively for the North, East and Up components at epoch 2010.0.
RESUMO
This paper examine the efficiency of energy use of three conservation tillage practices (SST - sub-soil tillage; MT - minimum tillage; and NT - no tillage) performed within two management zones, previously identified in a field according to the stability of yield variability. Experiments were carried out in 2003 in NE Italy, on a farm near Rovigo, on a 8-ha field with clay soil, in maize (Zea mays, L.). The purpose of the paper is (i) to investigate the energy variability due to these tillage practices performed spatially within two management zones and (ii) to analyze the long-term energetic efficiency for each tillage practice. The energy balance was highest for SST with respect to MT and NT, due to labor and fuel consumption rates. The energy balance was influenced by the spatial pattern of yield, with appreciable differences between practices in terms of both the conversion index of energy for tillage (9.0, 12.6 and 22.8GJha(-1) for SST, MT and NT, respectively) and the energy use efficiency for tillage (8.0, 11.6, 21.8GJha(-1) for SST, MT and NT, respectively). Based on the simulated data and the calibration results, SALUS model proved to be a good tool for analyzing long-term effects of tillage practices on yield. The NT treatment showed the best efficiency over years, due to the low inputs in comparison with the output level.
Assuntos
Agricultura , Zea mays/metabolismo , Itália , Modelos Teóricos , Zea mays/crescimento & desenvolvimentoRESUMO
The aberrant left pulmonary artery is a serious anomaly in neonates; in the adult it is most often an incidental finding. One case is reported, incidentally discovered in the diagnostic workup of a patient with a vertebral lytic lesion. This vascular anomaly, mimicking a mediastinal adenopathy on the chest roentgenogram, which also showed a peripheral lung malignancy, was better assessed by an esophagogram (indentation on the posterior tracheal wall as well as on the anterior esophageal wall) along with fluoroscopy which showed the lesion to be pulsating. Its thorough anatomic evaluation was allowed by computed tomography (CT), performed for the staging of the lung tumor. The latter proves the choice modality due to its capability to provide precise information on all the different structures existing in a given cross-section.