The complex space experiment Phobos will consist of two space probes carrying more than twenty experiments each. The primary purpose of the mission, launched in June 198B, is the exploration of the Mars satellite Phobos and of the planet itself. Various methods are used, including landing on the satellite and activation of its surface minerals by laser beam. During orbiting around Mars, the atmosphere of the planet will be studied. The secondary purpose is to study solar activity during the flight from Earth to Mars, gathering informations on solar wind, interplanetary shock waves, and gamma bursts. Solar X-ray activity will be monitored and solar
corona observed in X-rays; stereoscopic studies of the Sun will be made. The coordinator of the experiment is the Space Research Institute of the Academy of Sciences of the USSR, the other participants are from Austria, Bulgaria, Czechoslovakia, Finland, France, German Democratic Republic, German Federal Republic,
Hungary, Poland, Sweden, Switzerland and ESA.
Insects and other terrestrial arthropods are widely distributed in temperate and polar regions and overwinter in a variety of habitats. Some species are exposed to very low ambient temperatures, while others are protected by plant litter and snow. As may be expected from the enormous diversity of terrestrial arthropods, many different overwintering strategies have evolved. Time is an important factor. Temperate and polar species are able to survive extended periods at freezing temperatures, while summer adapted species and tropical species may be killed by short periods even above the freezing point.
Some insects survive extracellular ice formation, while most species, as well as all spiders, mites and springtails are freeze intolerant and depend on supercooling to survive. Both the degree of freeze tolerance and supercooling increase by the accumulation of low molecular weight cryoprotectant substances, e.g. glycerol. Thermal hysteresis proteins (antifreeze proteins) stabilise the supercooled state of insects and may prevent the inoculation of ice from outside through the cuticle. Recently, the amino acid sequences of these proteins have been revealed.
Due to potent ice nucleating agents in the haemolymph most Freeze tolerant insects freeze at relatively high temperatures, thus preventing harmful effects of intracellular freezing. Doe to the low water vapour pressure in frozen environments, supercooled terrestrial arthropods are at a risk of desiccation. Glycerol and other low molecular weight substances may protect against dehydration as well as against cold. In the arctic springtail Onychiurus arcticus, freezing is avoided due to dehydration in equilibrium with the ambient freezing temperature. Tn some frozen habitats terrestrial arthropods are enclosed by ice and survive an oxygen deficiency by anaerobic metabolism.
Suggestions for further research include investigating the nature of freeze tolerance, the physiology of prolonged exposures to cold, and the relation between desiccation, anaerobiosis and cold hardiness.
The Picone-type identity for the half-linear second order partial differential equation n∑ i=1 ∂ ⁄ ∂xi Φ (∂u ⁄ ∂xi) + c(x)Φ(u) = 0, Φ(u) := |u| p−2 u, p > 1, is established and some applications of this identity are suggested.
There are twenty-six species of the genus Psallus Fieber, 1858 (Phylinae: Phylini) documented in the Korean Peninsula. Three new species are described: Psallus cheongtaensis sp. n., P. ernsti sp. n. and P. suwonanus sp. n., and four species are reported from Korea for the first time: Psallus cinnabarinus Kerzhner, 1979, P. flavescens Kerzhner, 1988, P. loginovae Kerzhner, 1988, and P. roseoguttatus Yasunaga & Vinokurov, 2000. The genitalic structures of females and males are described and figured for most treated species. A key is provided for identifying all the Korean species., Ram Keshari Duwal ... [et al.]., and Obsahuje seznam literatury
A set of fourteen large-scale exposures of comet Bennett 1970 II between 1970 April 27 and 30 is evaluated. The solar wind velocity is determined for this period from the aberration angle of the plasma tail. Its radial component had a minimum valuo of 70-100 km/s in the comet's environment: 50° off the ecliptic at a distance of 1 AU from the Sun. This value is 3-4 times less than the satellite data recorded at the Earth's orbit. The two plasma kinks, visible on 1970 April 30 in the comet tail, moved from the nucleus at a mear. radial velocity of 81 and 76 km/s, respectively. No disconnection event appeared in the plasma tail.
The paper shows that the deviations of the plane of polarisation from the normal direction found by us are due to scattering of the polarised lights of the corona on ice-crystals in high layers of troposphere. Nevertheless, the deviations in the equatorial regions can hardly be explained in this way, and they seem to be real. and Součástí článku jsou fotografie s popisky v angličtině (nestránkováno)
The politicization of the Nabī Mūsā festival during the Palestine Mandate is a well-established and publicized fact, yet other Arab Palestinian festivals experienced a similar transformation in the same context. Such was the case of the Mawlid al-nabawī (the birthday of the Prophet Muhammad). The intention of Arab nationalists was that it should evolve into a communal festival for all the Palestinian Arabs. However, for mainly denominational, geographical and political reasons, the attempt met with varied success throughout the territory of the Palestine Mandate. Attendance at public festivities remained decidedly Muslim in character. Repeated appeals for Christian participation were to little avail. Yet the attempts to include Christian Arabs in the festival throw light on the Arab nationalist ideologies in Palestine at the time - from that point of view, the celebrations linked to the birth of the Prophet Muhammad stand out as an axiological inspiration, regardless of denominational boundaries. In 1937, the political mobilization on the occasion of the Mawlid al-nabawī reached a peak but, even then, attendance was greatest in Gaza and Acre, places where the festival was traditionally important. Furthermore, te degree of mobilization, varying as it did from place to place, seems to be a reflection of the influence of the main Arab Palestinian factions, whose rivalry was reaching a climax in the late 1930s.