Evaluating airborne and ground based gamma spectrometry methods for detecting particulate radioactivity in the environment: a case study of Irish Sea beaches

In several places, programmes are in place to locate and recover radioactive particles that have the potential to cause detrimental health effects in any member of the publicwho may encounter them. A model has been developed to evaluate the use of mobile gamma spectrometry systems within such programmes, with particular emphasis on large volume (16 l) NaI(Tl) detectors mounted in low flying helicopters. This model uses a validated Monte Carlo code with assessment of local geochemistry and natural and anthropogenic background radiation concentrations and distributions. The results of the model, applied to the example of particles recovered from beaches in the vicinity of Sellafield, clearly show the ability of rapid airborne surveys conducted at 75 m ground clearance and 120 kph speeds to demonstrate the absence of sources greater than 5 MBq 137Cs within large areas (10–20 km2 h−1), and identify areas requiring further ground based investigation. Lowering ground clearance for airborne surveys to 15 m whilst maintaining speeds covering 1–2 km2 h−1 can detect buried 137Cs sources of 0.5 MBq or greater activity. A survey design to detect 100 kBq 137Cs sources at 10 cm depth has also been defined, requiring surveys at b15 m ground clearance and b2 m s−1 ground speed. The response of airborne systems to the Sellafield particles recovered to date has also been simulated, and the proportion of the existing radiocaesium background in the vicinity of the nuclear site has been established. Finally the rates of area coverage and sensitivities of both airborne and ground based approaches are compared, demonstrating the ability of airborne systems to increase the rate of particle recovery in a cost effective manner. The potential for equipment and methodological developments to improve performance are discussed

Ornamental Prunus spp. as potential hosts of Plum pox virus

International audienc

Ornamental Prunus spp. as potential hosts of Plum pox virus

International audienc

Ornamental Prunus spp. as potential hosts of Plum pox virus

International audienc

Ornamental Prunus spp. as potential hosts of Plum pox virus

International audienc

Efeitos da sacarose e do nitrogénio inorgânico sobre a multiplicação "in vitro" de brotações de porta-enxerto de citros Effects of sucrose and inorganic nitrogen on multiplication of "in vitro" culture of poncirus trifoliata

O presente trabalho objetivou estudar os efeitos da sacarose e do nitrogênio inorgânico (NH4NO3 e KNO3) sobre a multiplicação "in vitro" de Poncirus trifoliata (L.) Raf. Brotos apicais obtidos através de sucessivas repicagens em meio Murashige & Skoog (MS) acrescido de BAP 1,0 mg/l e ANA 1,0 mg/l, foram transferidos para novo meio MS suplementado com as combinações de sacarose (0; 7,5; 15; 30; 45 e 60 g/l) e nitrogênio inorgânico (0; 1/4; 1/2; 1 e 2 MS) dos níveis presentes no meio MS. Os brotos foram mantidos a 2.500 Lux por 16 horas diárias, com temperatura de 27 ± 2°C. Após 45 dias de cultivo, avaliaram-se o número total de brotos e o número de brotos com medidas superiores a 1 cm de comprimento. Observou-se que as doses da sacarose e do nitrogênio inorgânico afetaram as carac-terísticas avaliadas, sendo as melhores respostas obtidas quando se utilizaram concen-trações entre 30 e 45 g/1 da sacarose associadas ao dobro da dose (2 MS) do nitrogênio inorgânico presente no meio MS.<br>It was studied the effects of sucrose and inorganic nitrogen on multiplication of (NH4NO3 and KNO3) "in vitro" culture of Poncirus trifoliata (L.) Raf. Apex buddings from successive multiplications in MS medium added with BAP l.0 mg/l and ANA l.0 mg/l were placed into new MS media where different tested combinations of sucrose (0; 7.5; 15; 30; 45 and 60 g/l) and inorganic nitrogen levels (0 MS; 1/4 MS; 1/2 MS; 1 MS and 2 MS) present in MS medium were tested. The buddings were maintained under the 2,500 lux for 16 daily hours at 27 ± 2°C. After 45 days they were evaluated according characteristics of total number of buds and number of buds higher than 1 cm long. The sucrose and inorganic nitrogen doses affected the rated characteristics. The best responses observed were between 30 to 45 g/l of sucrose associated with double (2 MS) dose of inorganic nitrogen

Cryptic genetic elements for regulation of gene expression in plants: The tcup gene expression system

Cryptic gene regulatory elements are a class of regulatory elements that possess the same activities as regulatory elements associated with genes but they are inactive at their native loca