A scanning x-ray microscope using synchrotron radiation

Focused synchrotron radiation collimated by means of a pinhole has been used to construct a scanning x-ray microscope capable of making stereoscopic element-discriminating pictures of relatively thick specimens in an atmospheric environment.     

Effect of protein level in purified diet and of density,ammonia and O2 level on growth of juvenile European eels (Anguilla anguilla L.)

The influence of protein level in a purified diet and of density on the growth of Anguilla anguilla in indoor and outdoor containers was examined. The average weight increase of eels that were fed on a diet of pellets containing 35%, 45%, or 55% protein was significantly higher than the mean weight increase of eels fed on pellets containing 25% protein. The production per m³ was higher in the groups fed 45% or 55% protein level in the diet than in the groups fed 25% or 35% protein. Dissolved oxygen in the water of the growing tanks was 7–9 ppm in all groups. Ammonia production was lower in the group fed on pellets containing 25% protein and higher in the groups receiving higher protein diets.Eel growth at low density (4 kg/m³) was almost the same as at high density (30 kg/m³) for both slowly growing and moderately growing eels. Production was higher in the groups stocked at high density and lower in those stocked at low densities. The production of slowly growing eels was lower than that of moderately growing eels.     

Competitive Effects of Three Perennial Weeds,Cynodon Dactylon (L.) Pers., Cyperns Rotundus L. and Sorghum Halepense (L.) Pers., on Young Citrus

One-year-old sour orange seedlings were grown with the perennial weeds Cynodon dactylon, Cyperus rotundus and Sorghum halepense in adjacent containers, which were either separated or linked. In the separated containers no effect due to aerial competition was apparent on citrus after ten months. In the linked containers citrus growing with weeds showed, after 3-4 months, severe reductions in plant height, stem diameter and leaf number. The addition of nitrogen slightly reduced the competitive effects of the weeds. The order of competitive capacity was C. dactylon<S. halepense<C. rotundus. When weed tops were removed, the citrus plants recovered within six months from the most severe damage. It is suggested that competitive effects are caused, at least in part, by phytotoxic substances produced by the weeds.     

Effect of drip and furrow irrigation methods on<Emphasis Type="Italic">Bemisia tabaci</Emphasis> populations in cotton fields

Effects of drip and furrow irrigation and their application at three different levels, onBemisia tabaci populations, were studied during the 1999 and 2000 growing seasons in Aydın, Turkey, with the objective of attaining water rates of 100% (full), 66% (2/3) and 33% (1/3) during irrigation periods. All plots were irrigated during four different phenological periods,viz., blooming, boll setting, boll and 5–10% of boll open stage. The number of whitefly immatures was significantly greater in furrow-irrigated than in drip-irrigated plots in both 1999 and 2000 and there were significant differences found in the effect of the irrigation methods and their application levels as well. In all trials, the number of whitefly nymphs was the highest in the 33% (1/3) water supply with both drip and furrow methods. http://www.phytoparasitica.org posting Feb. 3, 2003.     

Bermudagrass (cynodon dactylon): a history of the weed and its control in Israel

Bermudagrass (Cynodon dactylon) is a perennial grass, common and endemic in Israel. The expansion and intensification of agriculture which started in the region at the beginning of this century, induced severe infestation by bermudagrass, particularly in fruit orchards and irrigated fields. The characteristics of the weed are discussed. Methods for control of bermudagrass were developed gradually over the years by local farmers: from ‘bahar’ (manual removal of rhizomes from the soil) to deep plowing and serial cultivation. Since active herbicides became available in Israel (1960s) approximately 20 registered herbicides and mixtures have been used effectively against bermudagrass in most agricultural and industrial situations. Although herbicides are accepted at present for bermudagrass control by most farmers, it is important to re-assess alternative measures which were developed locally.     

Intraocular pressure and tear production in five herbivorous wildlife species

The intraocular pressure and rate of tear production were measured in 18 addax antelopes (Addax nasomaculatus), four impalas (Aepyceros melampus), 11 wide-lipped rhinoceroses (Ceratotherium simum), 10 white-tailed wildebeests (Connochaetes gnou) and seven scimitar-horned oryxes (Oryx dammah). The animals were anaesthetised with an intramuscular injection of etorphine hydrochloride and acepromazine maleate, and the Schirmer tear test I was used to evaluate tear production, and applanation tonometry was used to evaluate the intraocular pressure. The mean (sd) rate of tear production ranged from 17.6 (3.1) mm/minute in the rhinoceros to 28.8 (8.3) mm/minute in the addax. The intraocular pressure ranged from 8.0 (1.2) mmHg in the impala to 32.1 (10.4) mmHg in the rhinoceros. The rate of tear production in the addax and the intraocular pressure in the rhinoceros appear to be the highest values of these variables to have been reported in any species.