The direct and indirect sample transfer techniques for measuring airborne inorganic fibres concentrations were studied by TEM for airborne rockwool fibres, chrysotile, amosite and tungsten oxide whiskers. The number and mass concentrations of fibres with aspect ratios > or = 5, prepared by these two techniques for fibres longer than 0.5 mu m and 5 mu m, and the aspect ratios were evaluated and ...

Growing greenhouse vegetables is one of the most exacting and intense forms of all agricultural enterprises. In combination with greenhouses, hydroponics is becoming increasingly popular, especially in the United States, Canada, western Europe, and Japan. It is high technology and capital intensive. It is highly productive, conservative of water and land and protective of the environment. For p...

Rooting and shoot growth were evaluated on stem tip cuttings of砂pencumpe功ratum receiving various auxin soaking treatments. Five-cm-Iong stem tips (0.08 g fresh weight in average) were soaked in IAA, 1 BA, NAA and 2,4-D solutions at 5, 25 , 125μM for 10 min, and then placed in a rockwool block for three weeks. A deionized water soaking treatment was served as a control. The results indicated tha...

We argue that social capital places strong constraints on an entrepreneur’s ability to found a firm in a region in which he or she does not have connections. We examine this thesis using comprehensive data on the Danish population and find evidence broadly consistent with this claim. Entrepreneurs tend to open businesses in regions in which they have deep roots (‘home’ regions). We further find...

Techniques developed at the Harwell Laboratory for the determination of the biopersistence of man-made mineral fibers (MMMF) in vivo are described. Results obtained with samples of glass fiber with a range of compositions, and with a sample of rockwool, are summarized. With glass fibers the rate of dissolution of fibers in vivo depends not only on their chemical composition, but also on their l...