No abstract

No abstract

The objective of this research was to determine the effect of honeybee density on pollination and fruit set of the Hass avocado. The research was carried out in the municipality of Popayán, Colombia. Three avocado orchards were selected, each one with an area of one hectare and trees with an age of six years. The treatments were: 1) four hives/ha, 2) six hives/ha, and 3) control without hives. Treatments of six and four hives/ha presented significant differences with respect to the control, with a honeybee density per tree of 7.72, 6.04 and 2.72, pollination rate of 60, 55 and 50%, pollination efficiency of 7.57, 6.04 and 5.98 grains of pollen per stigma, 6.11, 4.13 and 3.54% fruit set initial, 0.058, 0.048 and 0.028% fruit set final, 231, 212 and 137 of fruits per tree, 46.2, 38.2 and 21.6 kg fruit per tree, respectively. The results obtained show an increase of honey-bee density per tree, pollination rate, pollination efficiency, % fruit set, % fruit set final, number of fruits per tree and total fruit weight per tree when six and four bee hives/ha are introduced in the avocado crop.

BP's largest subsea development, PSVM, sits in water depths of 2,000 metres located north-west of Luanda in block 31. It's the first ultra-deepwater development in the continent of Africa and the most expansive sub-sea development in the industry to date due to the combination of water depth and geographical spread. From the initial discoveries in 2002 to 2004, and as early project planning took shape in late 2005, it was realised the scale of the development, water depth, and location would present new challenges to the industry and BP. Given the reservoir quality, sand distribution, and highly unconsolidated formations, all zones of interest in the development require sand control completions. Because of the ultra-deep water depth and subsea infrastructure, intervention operations and costs are prohibitive; thus, completions are designed to minimize the need for interventions during the life of the well. This objective has driven the need for robust equipment design with respect to longevity, corrosion, erosion-resistant, and remote monitoring and control. The production wells were completed as open hole gravel packs, resulting in technical limit productivity along with exceptional mechanical reliability and integrity. All wells completed to date have shown zero formation damage, contributing to the planned field plateau production output of 150 Mbpd. To sustain this production capability, voidage replacement is important and therefore, the injection wells are mandated to deliver equivalent well performance through the use of effective sand-control completion designs. Based on this, cased hole frac-pack completions were selected for the initial gas injection wells and stand-alone screen completions for the water injectors. The injectors have set the bar for flow efficiency in high transmissibility reservoirs and are some of the largest injector completions in BP's portfolio. This paper discusses the keys to the successful delivery and well productivity of the first 7 out of 40 wells of this world class ultra-deep subsea development. It reviews the PSVM completion basis of design as well as incorporates completion best practices and lessons inherited from BP Angola's first deepwater project, Greater Plutonio and Angola Joint Venture operations (White et al, 2008).

ABSTRACT:The article presents results of research focused on the development of natural regeneration of beech stands in the National Natural Reserve Voděradské bučiny, based on information acquired in regeneration plots established in 2004 and 2009. After five years of the study, 5 different generations of beech, representing 97.4% of the whole woody regeneration, were registered. In the second year of life, the two oldest generations of seedlings had the highest mortality registered so far. The last year survival of seedlings was not influenced by increased canopy openings as a result of harvest or mortality. The data from a new plot with higher stand density confirmed the negative effect of high parent stand density on the formation of new regeneration. An elevated proportion of litter in the ground cover was found to be negatively related to the establishment and survival of beech seedlings.