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Dohler M.,Catalonia Technology Center of Telecomunications | Heath Jr. R.W.,University of Texas at Austin | Lozano A.,UPF | Papadias C.B.,AIT Inc | Valenzuela R.A.,Bell Laboratories
IEEE Communications Magazine | Year: 2011

This article originates from a panel with the above title, held at IEEE VTC Spring 2009, in which the authors took part. The enthusiastic response it received prompted us to discuss for a wider audience whether research at the physical layer (PHY) is still relevant to the field of wireless communications. Using cellular systems as the axis of our exposition, we exemplify areas where PHY research has indeed hit a performance wall and where any improvements are expected to be marginal. We then discuss whether the research directions taken in the past have always been the right choice and how lessons learned could influence future policy decisions. Several of the raised issues are subsequently discussed in greater details, e.g., the growing divergence between academia and industry. With this argumentation at hand, we identify areas that are either under-developed or likely to be of impact in coming years - hence corroborating the relevance and importance of PHY research. © 2006 IEEE. Source

Schoffel R.,IFSul | Boller W.,UPF
Engenharia Agricola | Year: 2015

Soy harvest matches seasons with shortage of dry matter supply for ruminant feeding in most Brazilian soy-growing areas. Agricultural machinery-producing companies must have market perception, observing new opportunities and developing equipment to meet costumers' needs. This paper aims to design, build, and test a device to collect soybean crop residues from the combine cleaning mechanism, consisting mainly of vegetable straw (chaff), and the other plant parts (stems) remain being deposited onto the ground. For equipment designing, we made use of the architectural design methodology proposed in the reference model for the agricultural machinery development process. The equipment was designed and built following the proposed methodology, then installed and put into operation in a John Deere 1165 combine. After initial testing and few adjustments, the device showed satisfactory chaff-collecting performance. The equipment consists of a screw conveyor assembled transversely to the combine and a centrifugal fan assembled on the side. The collected chaff is dumped into a trailer towed by tractor. Source

Swine farming generates great amount of manure that can be used as fertilizer in crops and pastures. The continuous application of swine waste may change the physical attributes of the soil. The present study aimed to verify the influence of 0, 48, 96, 144, 192 and 240 m3 ha-1 year-1 of pig slurry applications in a four-year time span on Oxisol in a perennial pasture. The mean content of dry matter in pig slurry was 1.72%. Soil samples of undisturbed and disturbed structures were collected in 0-0,05; 0,05-0,10; 0,10-0,15; 0,15-0,20; 0,20-0,25;0, 25-0,30 m layers. Organic matter content, texture, water dispersible clay, soil density, maximum bulk density, relative density, mechanical resistance to penetration, total porosity and macro, micro and criptopores volume, soil permeability to air, soil aggregates stability were evaluated. Organic matter content was the only attribute to show some interaction between dose and layer. The evaluated parameters were not influenced by application of different doses of pig slurry with dry matter of 1.72% for a period of four years in an Oxisol. Source

This experiment was carried out during April to August 2003 in a greenhouse at the Universidade Federal de Santa Maria, Rio Grande do Sul state, Brazil. The growth and production of nasturtium flowers (Tropaeolum majus) in hydroponics NFT system was typified. Treatments were displayed in a 3x11 factorial, with six replications, in entirely randomized experimental design, and were composed of three nutrition solutions and 11 assessment dates. Each plant was separated between aerial part and root for the evaluation of dry mass. The blossoming started 49 days after the transplant (DAT). The plants presented good development in hydroponics, as well as growing dry mass, stature, leaf area and IAF, during the cycle. The culture's growth rate presented larger accumulation of leaf mass from 49 DAT on, in linear relation. Biological productivity was adjusted to a 2nd degree equation. Nutrition solutions did not show statistical differences, however, Furlani (1997) solution was the most reasonably priced. Source

Tan spot is one of the main diseases of wheat in Brazil reducing grain yield up to 80%. Although the lesion expansion is an important component of the epidemics, there are few studies on its control by curative sprays of fungicide. To know how different fungicides may control lesion expansion and to improve disease management, four assays were carried out at the Universidade de Passo Fundo (UPF) in 2011. All assays were organized as randomized blocks, with four replicates, inside a growth chamber with control of light and temperature. In two assays a triazole (propiconazole) and a strobylurin (azoxystrobin) fungicides, as well as their mixture, were sprayed from one to 12 day intervals after inoculation of the wheat cultivars 'Fundacep Horizonte' and 'Quartzo'. Based upon measurements of the lesion size, the strobylurin did not reduce the rate of lesion growth (0.176 to 0.180 mm2.day-1) in comparison to the non-sprayed control (0.175 to 0.184 mm2.day-1), whereas the triazole (0.080 mm2.day-1) and the fungicide mix (0.060 to 0.080 mm2.day-1) did it if sprayed within 10 or 12 days after inoculation. In two other assays, commercial fungicides (epoxiconazole, propiconazole, tebuconazole, azoxystrobin, pyraclostrobin, cyproconazole + azoxystrobin, epoxiconazole + pyraclostrobin, protioconazole + trifloxystrobin and tebuconazole + trifloxystrobin) were sprayed onto plants at three, five and eight days after inoculation. Spraying of the fungicides epoxiconazole, propiconazole, and protioconazole + trifloxystrobin at five days reduced the rate of lesion expansion (0.07 to 0.14 mm2.day-1) over the control non-sprayed plants (0.29 mm2.day-1). Fungicide applications eight days had no effect on the rate of progress of lesions. The final lesion size was smaller (3.76 to 5.89 mm2) on plants sprayed with tebuconazole + trifloxystrobin, protioconazole + trifloxystrobin, tebuconazol, epoxiconazole + pyraclostrobin, and propiconazole, but higher (8.46 to 11.70 mm2) for cyproconazole + azoxystrobin, azoxystrobin, epoxiconazole, and pyraclostrobin, which did not differ from the non-sprayed control. These results show how difficult is to limit tan spot increase after disease establishment and indicate that is management requires the adoption of preventive control strategies. Source

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