Phytoluminography: Imaging Plants by Delayed Light Emission

It is demonstrated that photographic images of plants can be produced in the absence of external illumination using an image intensifier. The image is produced by the weak delayed light emission (afterglow) from photosynthetically active chloroplasts. We propose the use of such “phytoluminographs’ for the study and diagnosis at an early stage of disturbances due to parasites, mineral deficiency, herbicides, frost etc.     

Effect of pH, light intensity and population on the toxicity of the pesticide carbofuran to the blue-green alga Nostoc muscorum.

The effect of pH, light intensity and population on the toxicity of the pesticide furadan (containing 3% carbofuran as the active ingredient) was studied on the nitrogen fixing blue-green alga Nostoc muscorum. It was observed that all these factors had effects on the toxicity of the pesticide. The blue-green alga grew better in the pH range of 7.5-10, whereas the acidic pH of 5-6 retarded growth. The pesticide was more toxic to alga in the medium of pH 5-6, whereas reduction in toxicity was noticed in alkaline pH of 7.5-10. The alga grew slowly in a light intensity of 1,500 lux in comparison to a light intensity of 3,000 lux, and no growth occurred in the dark. The toxicity of the pesticide gradually decreased with increasing light intensity. The toxic effect of the pesticide was increased when the initial population level was low, and increasing the initial population reduced the toxicity.     

The Morphology of Thynnascaris adunca (Rudolphi) (Nematoda, Ascaridoidea)

The following body parts of the fish nematode Thynnascaris adunca were studied by using SEM and TEM: anterior and posterior ends, digestive tract, particularly the oesophagus and its glandular tissue, male and female reproductive organs, excretory and nervous systems, and body wall. The ova in the uterus of a female studied by SEM were found to contain II-stage larvae: this is at variance with previous reports. Contrary to accepted views, each body wall muscle was found to have more than one process ("arm") reaching the dorsal/ventral nerve.     

Study on Chemosensitive Hairs in Wolf Spiders (Araneae, Lycosidae) by Scanning Electron Microscopy

The occurrence of chemosensitive hairs in some lycosid species is examined. The distribution and shape of such hairs dorsally on the male subadult palpal tarsus and the cymbium are compared. In certain species (e.g. of the genera. Pardosa and Alopecosa) the cymbium has a dense covering of these hairs while there are rather few of these in the male subadult palpal tarsus. The cymbium of Aulonia atbimana has comparatively few chemosensitive hairs dorsally, a condition supposedly related to the web-building habit in this species. Indications are given that the cymbial chemosensitive hairs are involved in the detection of presumed contact sex pheromones produced by the female. Certain intergeneric differences in the shape of the apical part of the cymbial chemosensitive hairs are noted.     

Overwintering strategy of two closely related forms of Cloeon (dipterum?) (Ephemeroptera) from Sweden and England

SUMMARY. Comparison is made of resistance to anoxia at 0°C of an English and a Swedish winter larval population of two closely related forms of Cloeon (dipterum?). The English population was not very resistant but contained a few slightly resistant larvae; the Swedish population was very resistant. Swedish larvae initiated hibernation more rapidly than English larvae and were also more resistant to starvation. The different properties of the populations are seen as an adaptation to different winter conditions in ponds in England and Sweden. Evidence is presented that low temperatures but not decreasing photoperiod are decisive for the final induction of hibernation in the larvae. In Swedish larvae this induction starts at between 4 and 5°C.     

13C-Urea breath test is superior in sensitivity to detect Helicobacter pylori infection than either antral histology or rapid urease test.

There is no single technique which fulfils the criterion for a reference method to detect Helicobacter pylori (Hp) infection. The aim was to compare the results of antral histology (H), rapid urease test (U) and urea breath test (UBT) from antral biopsy samples in patients having gastric or duodenal lesions during upper GI endoscopy. We used the following methods: 1) biopsy specimens for histology (Warthin-Starry staining); 2) rapid urease test; and 3) 13C-urea breath test with infrared spectrometry. The total number of patients was 166 examined by H, U, and UBT. H, U and UBT were negative (-) in 64 patients and positive (+) in 51. The true positivity and false negativity (%, number of patients in parentheses) of each method based upon the positivity of the other two tests were: H+, U+ (54): UBT+, 94.4% (51) and UBT-, 5.6% (3); H+, UBT+ (57): U+, 89.5% (51) and U-, 10.5% (6); U+, UBT+ (65): H+, 78.5% (51) and H-, 21.5% (14). If Hp infection is considered to be positive when at least two tests detect the presence of Hp, UBT shows the highest sensitivity in comparison to histology of biopsy specimens and urease test. UBT is highly recommended as a screening test for Hp infection in patients presenting upper GI endoscopic alterations.     

A theoretical study on mathematical modelling of an infectious disease with application of optimal control

In this paper, we propose and analyze an epidemic problem which can be controlled by vaccination as well as treatment. In the first part of our analysis we study the dynamical behavior of the system with fixed control for both vaccination and treatment. Basic reproduction number is obtained in all possible cases and it is observed that the simultaneous use of vaccination and treatment control is the most favorable case to prevent the disease from being epidemic. In the second part, we take the controls as time dependent and obtain the optimal control strategy to minimize both the infected populations and the associated costs. All the analytical results are verified by simulation works. Some important conclusions are given at the end of the paper.