MetroPCS

Abstract: The surface of Venus is a hostile environment, with a surface temperature averaging 452°C, and atmospheric pressure of 92 bars of carbon dioxide. Nevertheless, exploration of the surface of Venus is of scientific interest. Technologies currently being developed at NASA bring the operation of robots on Venus into the range of feasibility. These include high-temperature electronics; radioisotope power systems that operate at Venus temperatures; Stirling-based power and cooling systems to keep mission components within temperature constraints; high-temperature, corrosion-resistant materials; and hightemperature sensors, motors, actuators, and bearings. This paper presents the results of a design study for a Venus rover, with the goal of surface exploration capability that is comparable to that of Mars rover missions. The most critical portion of the design is the power and cooling system required for operation at Venus, and this analysis will comprise most of the work presented. The thermal design requires operation at an external temperature as high as 500°C. To minimize external heat flow into the electronics enclosure (and also to provide maximum structural strength against external pressure) the electronics enclosure is assumed to be spherical shell. A radioisotope Stirling Duplex engine provides electrical power and 2-stage cooling. In order to minimize heat leaks, the number of penetrations to the thermal enclosure was minimized. Optical instruments were assumed to operate through sapphire windows, and all the components that could be operated in the high-temperature Venus environment were located outside the enclosure. Total rover design mass (including cruise and EDL system) is 872 kg without growth, and 1059 kg with mass growth allowance included; this is easily within the launch capability of an expendable launch vehicle. There are no apparent showstoppers to the design of a rover capable of operation on the Venus surface, although some of the technologies will still need development to bring them to flight readiness.

Abstract: Tetraploids were induced in Spathiphyllum wallisii Regel (2n = 2x = 30) through in vitro application of mitosis inhibitors. Tetraploids were compared to the original diploid control plants. Polyploidization had a significant effect on plant anatomy and morphology. The stomatal area of diploids was smaller compared to the tetraploid plants. The leaf angle was smaller in diploids. The stomatal length and width, leaf thickness and angle and thickness of the spathum were positively correlated to the higher ploidy level. On the other hand, stomatal density, length/width ratio of leaf, spathum and spadix, number of shoots and leafs and length of the flower stalk decreased in tetraploids compared to the corresponding diploid controls. The leaf number of diploid plants was higher compared to tetraploids. Altogether, this study quantified the extended morphological changes of chromosome doubling in our model crop Spathiphyllum wallisi

Abstract: In conventional olive growing, the frequent tillage has reduced soil organic matter content. Recently, soil conservation is becoming a priority in management strategies of rural areas due to the awareness of the deterioration of this natural resource and of the difficulty of its recovery in short periods (i.e. cross compliance concept in European Union). Therefore, the conventional agronomic practices should evolve to a more sustainable olive management to improve soil quality and water saving. A better understanding of soil ecology could lead to identify agricultural management practices that support and stimulate soil organisms for beneficial purposes in agriculture. The aim of this study was to evaluate the effects of sustainable practices (grass cover and pruning residues recycling) on soil quality in a Mediterranean olive orchard. The trials were carried out in a mature olive grove (Olea europaea L. – cv Maiatica) located in Basilicata Region (Southern Italy) and managed according to two different soil management systems: the sustainable treatment (ST) and the conventional treatment (CT). Soil microbiological quality in the two systems was monitored by both microbiological cultural-dependent and molecular methods. In the ST olive orchard, soil microbiota showed a higher complexity and metabolic diversity. The adoption of ‘innovative’, sustainable, agricultural practices had positive effects on soil microbiota and its biodiversity which can influence soil fertility and plant growth by increasing nutrients availability and turnover. The results of this study encourage the use of sustainable agricultural practices able to enhance soil fertility and promote good-quality fruit production without detrimental effects on water and soil resources.