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In the first 25 generations of his classical mutation accumulation experiment, T. Mukai estimated a large rate of early linear decay for the relative viability of Drosophila melanogaster chromosome II (delta MII = 0.004). Mukai forced through zero the regression of viability decline on generation number, but it has recently been shown (Fry, 2001) that a similar decline (delta MII = 0.006) is ob...

This paper analyses the correlation between employment duration, unemployment duration and general skill accumulation in a search equilibrium. I show how the level of general skills and the duration of employment are positively correlated, and both variables are negatively correlated with the duration of unemployment spells. With search frictions, general skill accumulation is associated with a...

background: due to the presence of radioactive minerals such as monazite, the beach sand of the west coast of kanyakumari exhibits high natural background radiation. hair is a good indicator of radionuclides in the human body. an attempt is taken to measure the 210po activity in human hair samples and the factors affecting it. material and methods: 210po activity was analysed in 47 individuals ...

heavy metal pollution plays an important role in global biodiversity decline. however, there is paucity of information concerning the effects of metals on amphibians. in the present study, investigations were made on the accumulation of heavy metals, copper (cu) and lead (pb) in water, sediment and tadpoles inhabiting the water bodies of barak valley, assam. tadpoles of six different anuran spe...

vacuolar h+-translocation pyrophosphatase (v-ppase) and na+/h+ antiporter (v-na+/h+) are important transporters in plant cells and have essential roles against abiotic stresses. in this study, the effects of salt stress were surveyed on the transcription of v-ppase pump and na+/h+ antiporter genes at early times of nacl treatment in roots of halophytic grass leptochloa fusca through the real ti...

phytoextraction is a remediation technology that uses plants to remove heavy metals from soil. the success of a phytoextraction process depends on adequate plant yield (aerial parts) and high metal concentrations in plant shoots. a pot experiment was conducted to investigate the combination effects of plants [sunflower (helianthus annuus) and canola (brassica napus)] with soil treatments (manur...

duckweeds are of special interest, as they are naturally growing weeds that have the capacity to tolerate and remove toxic pollutants, including heavy metals from the environment. studies have revealed that duckweed (lemna minor) can tolerate and remove heavy metals from aqueous solutions. in the present study, the efficiency of l. minor in the removal of ni and cr individually from aqueous sol...

copper (cu) is an essential element required by all living organisms, since at least 30 enzymes are known to use cu as a cofactor. cu is also toxic in excess and liver and gills are known to be target organs for it. in the present study, 240 siberian sturgeon juvenile (with initial weight 29.2 ± 3.1 g and initial length 21.8 ± 1.4 cm) were randomly distributed in 12 fiberglass tanks at 4 differ...