Estimation of the limitations for surficial water addition above a potential high level radioactive waste repository at Yucca Mountain, Nevada; Yucca Mountain Site Characterization Project

The Yucca Mountain Site Characterization Project is studying Yucca Mountain in southwestern Nevada as a potential site for a high-level nuclear waste repository. Site characterization includes surface-based and underground testing. Analyses have been performed to design site characterization activities with minimal impact on the ability of the site to isolate waste, and on tests performed as part of the characterization process. One activity of site characterization is the construction of an Exploratory Studies Facility, consisting of underground shafts, drifts, and ramps, and the accompanying surface pad facility and roads. The information in this report addresses the following topics: (1) a discussion of the potential effects of surface construction water on repository-performance, and on surface and underground experiments; (2) one-dimensional numerical calculations predicting the maximum allowable amount of water that may infiltrate the surface of the mountain without affecting repository performance; and (3) two-dimensional numerical calculations of the movement of that amount of surface water and how the water may affect repository performance and experiments. The results contained herein should be used with other site data and scientific/engineering judgement in determining controls on water usage at Yucca Mountain. This document contains information that has been used in preparing Appendix I of the Exploratory Studies Facility Design Requirements document for the Yucca Mountain Site Characterization Project

Biomimicry: further insights from ant colonies?

Biomimicry means learning from nature. Well known examples include physical structures such as the Velcro fastener. But natural selection has also "engineered" mechanisms by which the components of adaptive biological systems are organized. For example, natural selection has caused the foragers in an ant colony to cooperate and communicate in order to increase the total foraging success of the colony. Ant colony optimization (ACO) is based on the pheromone trails by which many ant species communicate the locations of food in the environment around the nest. Computer algorithms based on ACO perform well in hard computational problems like the Traveling Salesman Problem. ACO algorithms normally use only a single attractive "pheromone". However, it seems that real ants use more. The Pharaoh's ant, Monomorium pharaonis, uses three different trail pheromones to provide short-term (volatile) and long-term attraction (non-volatile) and short-term (volatile) repellence so that foragers are directed to particular locations of the trail system where food can be collected. In addition, Pharaoh's ants also extract information from the geometry of the trail system and have division of labour among the forager workers, some of whom specialize in laying and detecting pheromone trails. ACO takes inspiration from ant colonies but does not need to faithfully model how ant colonies solve problems. For example, in ACO "pheromone" is applied retroactively once an "ant" has returned to the nest, which is something that can easily be implemented in a computer program but is obviously something that real ants cannot do. This raises the possibility that ACO might benefit from taking further inspiration from ant colonies. Presumably, real ants use multiple information sources and communication signals for a reason

Atividades de coleta e origem floral do pólen armazenado em colônias de Plebeia saiqui (Holmberg) (Hymenoptera, Apidae, Meliponinae) no sul do Brasil Collection activities and floral origin of the stored pollcn in colonies of Plebeia saiqui (Holmberg) (Hymenoptera, Apidae, Meliponinae) in south Brazil

<abstract language="eng">Four colonies of Plebeia saiqui (Holmberg, 1903), of São Francisco de Paula, were studied during the period from October/1998 to October/1999. The counting of the bees was proceeded monthly, differentiated workers that came back with and without pollen in the corbicula. Grains of pollen of pots previously marked were collected monthly and identified. The percentage of the pollen types of the samples was estimated: 20% of Asteraceae, 17% Myrtaceae, 15% type Meliaceae and 10% Euphorbiaceae. The remaining corresponds to other pollen types of small representation, besides those the were no identified. The climatic influence on the pollen collection was analyzed being used simple and multiple regressions. It was verified that in the spring and in the summer the temperature, the solar irradiation and relative humidity were significant for the pollen foraging. During autumn and winter the relative humidity had smaller influence in the pollen collection