Laboratory studies on the biology of Simulium nigritarse Coquillett and Simulium adersi Pomeroy (Diptera : simuliidae)

The articles have been scanned in colour with a HP Scanjet 5590; 300dpi. Adobe Acrobat XI Pro was used to OCR the text and also for the merging and conversion to the final presentation PDF-format.The eggs of both Simulium nigritarse and S. adersi took up to 13 days to hatch in water at a temperature of 25 °C. The larvae of S. nigritarse required a minimum of 20 days and those of S.adersi a minimum of 17 days to pupate when reared in water at 20± 1 °C. No difference between the sexes was observed in the time taken by the larvae of either species to complete their life cycle. The duration of the pupal stage of S. nigritarse ranged from a minimum of 47 hours at 25 °C to a maximum of 569 hours (23,7 days) at 6 °C. An ambient temperature of 30± 1°C was lethal for both the larvae and the pupae of S. nigritarse. Eclosion of S. nigritarse reaches a peak after sunrise, then the rate declines towards sunset. A mean of 76% of the flies were found to hatch during the day. The time of eclosion of both males and females was similar. Pupation of S. nigritarse could take place at a water-depth of 2m and was common at a depth of 1,1 m. In still water no negative geotropism could be detected in the behaviour of S. nigritarse larvae and they were positively phototropic. In agitated water larvae did not respond to a light gradient ranging from 5 to 1100 lux. Adult larvae became negatively phototropic before the onset of pupation, which took place in dark, fast-flowing water. S. nigritarse can overwinter in both the larval and the pupal stages

The control of Simuliidae (Diptera, Nematocera) in South African rivers by modification of the water flow volume

It was found that the build-up of simuliid numbers subsequent to the construction of dams in the Vaal and Orange Rivers could be successfully prevented by periodic, artificially controlled reductions in the water-levels in these rivers.The articles have been scanned in colour with a HP Scanjet 5590; 600dpi. Adobe Acrobat XI Pro was used to OCR the text and also for the merging and conversion to the final presentation PDF-format

Breakup Density in Spectator Fragmentation

Proton-proton correlations and correlations of protons, deuterons and tritons with alpha particles from spectator decays following 197Au + 197Au collisions at 1000 MeV per nucleon have been measured with two highly efficient detector hodoscopes. The constructed correlation functions, interpreted within the approximation of a simultaneous volume decay, indicate a moderate expansion and low breakup densities, similar to assumptions made in statistical multifragmentation models. PACS numbers: 25.70.Pq, 21.65.+f, 25.70.Mn, 25.75.GzComment: 11 pages, LaTeX with 3 included figures; Also available from http://www-kp3.gsi.de/www/kp3/aladin_publications.htm

De invloed van licht op onze gezondheid : te weinig 'lichtvitaminen' kan leiden tot lichamelijke klachten

Wetenschappelijk onderzoek heeft de laatste tien jaar het inzicht vergroot in de niet-visuele invloed van licht op de geestelijke en lichamelijke gezondheid van de mens. Vooral ten aanzien van de werking en effecten van oculair licht (licht via het oog) is meer bekend. In januari van dit jaar is in tijdschrift Science voor het eerst wetenschappelijk aangetoond dat langs niet-oculaire weg (instraling via de huid in de bloedbaan) zichtbaar licht de biologische klok kan verschuiven. Licht veroorzaakt dus aanzienlijk meer in de mens dan tot nu toe werd aangenomen

De invloed van licht op onze gezondheid : te weinig 'lichtvitaminen' kan leiden tot lichamelijke klachten

Wetenschappelijk onderzoek heeft de laatste tien jaar het inzicht vergroot in de niet-visuele invloed van licht op de geestelijke en lichamelijke gezondheid van de mens. Vooral ten aanzien van de werking en effecten van oculair licht (licht via het oog) is meer bekend. In januari van dit jaar is in tijdschrift Science voor het eerst wetenschappelijk aangetoond dat langs niet-oculaire weg (instraling via de huid in de bloedbaan) zichtbaar licht de biologische klok kan verschuiven. Licht veroorzaakt dus aanzienlijk meer in de mens dan tot nu toe werd aangenomen

Daylight artificial light and people in an office environment, overview of visual and biological responses

Abstract Long-term behaviour/response of people has been studied in standard window zone offices during daytime working hours. Regular cell-offices were equipped with experimental lighting systems delivering lighting conditions that are known to influence human physiology. The results show that most people prefer to follow a daylight cycle instead of a constant level. Preferred lighting levels are significantly higher than today's indoor lighting standards and correspond to levels where biological stimulation can occur. The results strongly suggest that meeting biological lighting needs is very different from meeting visual needs. Results of two permanent occupants show striking differences in lighting settings, which correspond to individual circadian cycles and performance. This strengthens that present indoor lighting levels (and standards) are too low for biological stimulation. Medical research has shown that a prolonged lack of 'light vitamin' can cause health problems ranging from minor sleep and performance difficulties to major depressions. This inevitably suggests that "poor' indoor lighting is the underlying cause of many of the health and performance problems. By naming this the 'ill-lighting syndrome' we may well have identified the fundamental mechanism that can result in many different negative health/performance effects. Creating healthy indoor lighting can be a simple form of preventive medicine and providing a new challenge for the lighting community