Results 1 - 10 of 222
Results 1 - 10 of 222. Search took: 0.03 seconds
|Sort by: date | relevance|
[en] Nuclear technology and nuclear energy in Israel and in other countries as well, are suffering from 'bad reputation', originating from both ignorance and misleading publicity. In order to provide the public, and especially the young generation, with objective and comprehensive facts and data, the Israeli Atomic Energy Commission (IAEC), and the Nuclear Research Center - Negev (NRCN) decided to create a permanent exhibition in Beer Sheva, covering Nuclear Technology. Similar activity was done in other countries, such as France, Slovenia and others.
[en] A three years experimental essay has been carried out to determine the efficacy of the gamma irradiation for the prophylactic treatment of hive equipment and for the integrated management and control of diseases. The impact of the nuclear techniques on the production yields of the hive has been also evaluated. The results show that the gamma irradiation is a suitable complementary tool to sterilize hive equipment as a non-destructive and low cost method. (author)
[en] Highlights: ► Prohibited operating zone economic dispatch problem has been solved by IABC-LS. ► The losses used in the solution of the problem have been computed by B-loss matrix. ► IABC-LS method has been applied to three test systems in literature. ► The values obtained by IABC and IABC-LS are better than the results in literature. - Abstract: In this study, prohibited operating zone economic power dispatch problem which considers ramp rate limit, has been solved by incremental artificial bee colony algorithm (IABC) and incremental artificial bee colony algorithm with local search (IABC-LS) methods. The transmission line losses used in the solution of the problem have been computed by B-loss matrix. IABC, IABC-LS methods have been applied to three different test systems in literature which consist of 6, 15 and 40 generators. The attained optimum solution values have been compared with the optimum results in literature and have been discussed.
[en] We present a small single camera imaging system that provides a continuous 2800 field of view (FOV) inspired by the large FOV of insect eyes. This is achieved by combining a curved reflective surface that is machined into acrylic glass with lenses covering the frontal field that otherwise would have been obstructed by the mirror. Based on the work of Seidl (1982 PhD Thesis Technische Hochschule Darmstadt), we describe an extension of the 'bee eye optics simulation' (BEOS) model by Giger (1996 PhD Thesis Australian National University) to the full FOV which enables us to remap camera images according to the spatial resolution of honeybee eyes. This model is also useful for simulating the visual input of a bee-like agent in a virtual environment. The imaging system in combination with our bee eye model can serve as a tool for assessing the visual world from a bee's perspective which is particularly helpful for experimental setups. It is also well suited for mobile robots, in particular on flying vehicles that need light-weight sensors.
[en] Debates on causality are at the core of controversies as regards environmental changes. The present paper presents a new method for analyzing controversies on causality in a context of social debate and the results of its empirical testing. The case study used is the controversy as regards the role played by the insecticide Gaucho, compared with other supposed causal factors, in the substantial honeybee (Apis mellifera L.) losses reported to have occurred in France between 1994 and 2004. The method makes use of expert elicitation of the perceived strength of evidence regarding each of Bradford Hill's causality criteria, as regards the link between each of eight possible causal factors identified in attempts to explain each of five signs observed in honeybee colonies. These judgments are elicited from stakeholders and experts involved in the debate, i.e., representatives of Bayer Cropscience, of the Ministry of Agriculture, of the French Food Safety Authority, of beekeepers and of public scientists. We show that the intense controversy observed in confused and passionate public discourses is much less salient when the various arguments are structured using causation criteria. The contradictions between the different expert views have a triple origin: (1) the lack of shared definition and quantification of the signs observed in colonies; (2) the lack of specialist knowledge on honeybees; and (3) the strategic discursive practices associated with the lack of trust between experts representing stakeholders having diverging stakes in the case.
[en] Crithidia mellificae, a trypanosomatid parasite of Apis mellifera, has been proposed to be one of the pathogens responsible for the serious honey bee colony losses produced worldwide in the last decade, either alone or in association with Nosema ceranae. Since this pathogenic effect contradicts the results of the experimental infections originally performed by Langridge and McGhee nearly 40 years ago, we investigated the potential linkage of this protozoan with colony decline under laboratory conditions. Nosema-free and trypanosomatid-free honey bees from three different colonies were experimentally infected with fresh C. mellificae spheroid forms (reference strain ATCC30254), with N. ceranae fresh spores and with both parasites at the same time. Replicate cages were kept at 27 °C and used to analyse survival. C. mellificae spheroid forms did not reduce significantly the survival of the worker bees (64.5% at 30 days post-infection vs. 77.8% for the uninfected bees used as controls; differences were non statistically significant) under these experimental conditions. In contrast, the cages infected with N. ceranae exhibited higher rates of mortality from the 20th day post-infection onwards, irrespective of the presence of C. mellificae, suggesting that the spheroid forms of the latter have no pathological effect on A. mellifera. (Author)
[en] The most efficient Levy flight (scale-free) searching strategy for N independent searchers to adopt when target sites are randomly and sparsely distributed is identified. For N=1, it is well known that the optimal searching strategy is attained when μ=2, where the exponent μ characterizes the Levy distribution, P(l)=l-μ, of flight-lengths. For N>1, the optimal searching strategy is attained as μ->1. It is suggested that the orientation flights of honeybees can be understood within the context of such an optimal cooperative random Levy flight searching strategy. Upon returning to their hive after surveying a landscape honeybees can exchange information about the locations of target sites through the waggle dance. In accordance with observations it is predicted that the waggle dance can be disrupted without noticeable influence on a hive's ability to maintain weight when forage is plentiful
[en] There are close to 120 species of native stingless bees in Colombia, many of them with important uses and meanings for diverse social and cultural groups. The stingless beekeeping (meliponiculture) is an activity in process of growth and technification in Latin America and other regions, but there are a little information about their characteristics and development in Colombia. Through information collected by interviews to 75 stingless beekeepers of 16 departments of Colombia, 25 species of stingless bees were identified, grouped in 12 genera. Approximately nine more uncertain species were also found, four new records for the country are presented, and geographical distribution, urban beekeeping and vernacular names reported. The characteristics of most common cultivated genera (Tetragonisca, Melipona, Paratrigona, Scaptotrigona and Nannotrigona) are presented, and the importance of the link between biological and cultural diversity revealed in vernacular names, are discussed. Facing a growing of meliponiculture in the world, some research needs and risks for the conservation and management of the diversity of stingless bees and related knowledge are remarked.
[en] The construction process of the honeycomb by bees is an astonishing process. The original structure which the bees built is nothing more than a lot of rough cylinders. But keeping the beeswax semi-flow for a certain time, those rough structures become perfect hexahedral columns. A modified, simplified particle method was used here to simulate the semi-flow state of the material. Although the parameters used here were still rather subjective, the simulation still could demonstrate some behavior of that sort of material like beeswax. And the method that the bees used to build their honey comb, could be an efficient method to imitate when we are trying to manufacture cellular materials.