ALBERT

Beschreibung: The analysis of crustal stresses is a prerequisite for a detailed investigation of intraplate tectonic processes. This study restricts to the interpretation of the directions of maximum horizontal stresses, both from earthquake fault plane solutions (direction of pressure axes) and sigma-1 axes of in situ stress-measurements. In the W part of Central Europe the well-known NNW-SSE-directed compressive stresses are dominant. But other directions characterize the region joining eastward in the forefield of the East European platform. Numerical model calculations were carried out to interpret the collected stress features. Therefore, the plane stress state of the investigated region was simulated by an elastic plate under prescribed boundary loading. The governing equilibrium equations have been solved by a finite element procedure.-Authors

Beschreibung: Aus einer Analyse des Standes und der Grenzen von Astasierungen in Seismographensystemen wird ein Vorschlag für eine dynamische Astasierung abgeleitet. Diese wird theoretisch untersucht und für eine Anwendung auf einem Rechner modelliert. Eine Erhöhung der Eigenperiode Ts auf ca. 5 Ts für den Nutzsignalbereich ist erreichbar, Die Anwendung auf andere mechanische Schwinger ist möglich.

Beschreibung: Nach einführenden Betrachtungen über die Definition der Zeiteinheit, die Bereitstellung von Zeitskalen und die dabei zu berücksichtigenden relativistischen Effekte werden im 2. Abschnitt die Anforderungen moderner geodätischer Meßverfahren an die Zeit- und Frequenzmaßtechnik abgeleitet. Das Prinzip dieser Verfahren besteht darin, Entfernungen aus der Messung von Signallaufzeiten bei bekannter Lichtgeschwindigkeit und Entfernungsänderungen z. B. über den Dopplereffekt aus Frequenzänderungen zu bestimmen. Dabei werden hohe Anforderungen an die Zeit- und Frequenzmaßtechnik gestellt. Die aus der Analyse dieser Verfahren abgeleiteten Werte sind in einer Tabelle zusammengefaßt worden. Die hohen Anforderungen und die zu erwartende Entwicklung weiterer Varianten geodätischer Meßverfahren waren Anlaß dafür, den Entwicklungsstand der Zeit- und Frequenzmeßtechnik sowie erkennbare Tendenzen der Weiterentwicklung grundlegend zu analysieren und darzustellen. Im 3. Abschnitt werden deshalb Frequenznormale und die Messung ihrer Instabilität, Verfahren zum Zeitakalenvergleich, Verfahren zur Übertragung von Normalfrequenzen sowie Verfahren zur Zeitintervallmessung untersucht. Der im 4. Abschnitt durchgeführte Vergleich mit den Anforderungen moderner geodätischer Meßverfahren zeigt, daß deren Leistungsfähigkeit durch den Stand der Zeit- und Frequenzmeßtechnik nicht beeinträchtigt wird.

Beschreibung: The gravitational potential of the earth has been presented in a spherical harmonic series that is complete to degree and order 250. This solution has been obtained by first carrying out a combination of satellite derived potential coefficients (GEML2') with a set of 1 deg by 1 deg mean free air anomalies. These anomalies were formed from a merger of a June 1986 terrestrial set and a set derived from Geos-3/Sesat altimeter data. The combination solution was carried out after making downward continuation corrections to the surface anomalies and ellipsoidal corrections to the a priori potential coefficients. The adjustment yielded 582 potential coefficients and 64800 1 deg by 1 deg anomalies. Two combination solutions were made, one (OSU86C) that excluded geophysically predicted anomalies and one (OSU86D) that included 5547 such anomalies. The potential coefficients are determined through an optimal estimation procedure where, primarily, sampling error was minimized. Tests of the new solution were made by comparing undulation residuals at Doppler stations, and by using the field, up to degree 36, in orbit calculations. In North American the root mean square undulation difference was + or - 1.55 m. The undulation residuals are found to correlated with elevation although it is not clear why.

Beschreibung: In recent years more and more data has become available about focal depth of intra-crustal earthquakes as well as structure and distribution of physical and geologic-petrological parameters as a function of depth. This allows us to study the causes for increased earthquake occurrence at certain depth intervals. Besides structural and material inhomogeneities this is mainly controlled by depth and temperature-dependent variations of rheological properties of crustal materials. Intra-crustal earthquakes occur in an intraplate environment almost exclusively in the depth-range 2km 〈 h 〈 20km with a clear maximum of activity between some 5 to 15km. The petrophysical as well as possible geologic-petrological reasons are discussed. The brittle fracture behaviour of crustal material is strongly controlled by the v"SUB p"/v"SUB s"-ratio. In crustal regions with v"SUB p"/v"SUB s" = or 〉 1.8 there is obviously no seismic activity. -from Authors

Beschreibung: Beschreibung: Two potential coefficient fields that are complete to degree and order 360 have been computed. One field (OSU86E) excludes geophysically predicted anomalies while the other (OSU86F) includes such anomalies. These fields were computed using a set of 30' mean gravity anomalies derived from satellite altimetry in the ocean areas and from land measurements in North America, Europe, Australia, Japan and a few other areas. Where no 30' data existed, 1 deg x 1 deg mean anomaly estimates were used if available. No rigorous combination of satellite and terrestrial data was carried out. Instead advantage was taken of the adjusted anomalies and potential coefficients from a rigorous combination of the GEML2' potential coefficient set and 1 deg x 1 deg mean gravity anomalies. The two new fields were computed using a quadrature procedure with de-smoothing factors. The spectra of the new fields agree well with the spectra of the fields with 1 deg x 1 deg data out to degree 180. Above degree 180 the new fields have more power. The fields have been tested through comparison of Doppler station geoid undulations with undulations from various geopotential models. The agreement between the two types of undulations is approximately + or - 1.6 m. The use of a 360 field over a 180 field does not significantly improve the comparison. Instead it allows the comparison to be done at some stations where high frequency effects are important. In addition maps made in areas of high frequency information (such as trench areas) clearly reveal the signal in the new fields from degree 181 to 360.

Beschreibung: Additional keywords: refraction seismic, tectonic stress

Beschreibung: This brief guide has been prepared during a stay in Malaysia as an aid to local collectors and turned out to fulfil a need. A wider public may find it of use as well. The writer gratefully acknowledges improvements by Dr. C. Bas, Leiden. (Ed.) As agarics and boleti belong to the most common, but also to the most difficult fungi to collect and preserve, this guide is written particularly for this group of macromycetes. Obviously many recommendations and indications will apply to other fungi with fleshy fruit-bodies as well. Macromycetes with nonfleshy fruit-bodies can be treated in the same way, but for identification afterwards extensive descriptive notes are usually not necessary.

Beschreibung: Everybody visiting the Cibodas Mountain Garden must have observed that on the North side of Mt. Pangerango there are roughly between 2300 and 2700 m several sizeable pale green patches visible in the dark green montane forest. They were never visited and it intrigued me to know their vegetation which clearly must differ from the surrounding forest. End May 1950 a rintis was made from Kandangbadak at the base of the Pangerango proper westwards to a large northern spur of Mt. Pangerango, the so-called Geger Prut, over which one can descend to Cibeureum from where the trail to Cibodas can be resumed. The rintis was prepared by Mr. Verheul and Mr. Nurta, curators of the Cibodas Garden. This appeared to be quite an effort, as the rintis went up and down crossing many small ravines. Incidentally we found between the second and third ravine in a lighter place Berberis wallichiana and Anaphalis maxima, both then new for Mt. Gedeh, the latter a very rare species. At times we had to tunnel our way through very large stands of Gleichenia (paku andam), consisting of G. linearis, G. longissima and G. volubilis. These stands are characteristic for earthslides. After three hours having crossed eleven small ravines we reached a singular open sloping rocky plateau, which we called Tegal padas, from where we had a clear view on Cibodas and Rarahan; the altitude was ca. 2600 m. The dimensions of the tegal were estimated at 200—300 by 100—200 m. Soil was almost absent, the stony surface consisted of cemented irregular gravel. A tiny stream cut through it, of which the bottom was a solid dark glassy rock. The preliminary conclusion was that the structure was a lava stream overlain by lahar material. For about 50% the palish rocky surface was visible with a large number of ground lichens identified by Mr. Groenhart as belonging to Stereocaulon, one Baeomyces and two Lecidiaceae. The vegetation was sparse: there were no Gleichenias and no grasses. All woody plants were dwarfed: Rhododendron retusum, Gaultheria fragrantissima, G. nummularioides, Symplocos sp., Eurya sp., Vaccinium varingifolium. Of herbaceous plants I noted several species of Lycopodium (L. cernuum, L. clavatum, L. volubile), Dianella javanica, Nepenthes sp. Along the brook were some specimens of Myriactis nepalensis, Valeriana hardwickii, Thalictrum javanicum, Gahnia javanica and Astilbe indica, obviously descended by water dispersal. Specimens of Leptospermum flavescens flowered in 20 cm high dwarf shrubs.

Beschreibung: Fries (1821: 11) established Agaricus series Derminus tribus Inocybe, which was later elevated by him to generic rank (Fries, 1863: 346). Originally Fries based his circumscription of Inocybe solely on macroscopical characters; when it was raised to generic status Fries added that the spores of all Inocybe species were seemingly rough (’sporae scabrae videntur omnibus Inocybis communes’). Almost certainly this was not based on original observation, as Fries considered the use of the microscope unnecessary, but the result of an uncritical appraisal of observations by Berkeley (1860). The relevance of Fries’s statement regarding the typification of Inocybe is discussed on p. 29. Although the genus Inocybe is easily recognisable by macroscopical characters, judging from the fact that the generic concept has scarcely changed to the present day, the delimitation of species is considerably more difficult. The number of species increased continually from 1821 onwards. Massee (1904) published a world monograph of the genus but his work unfortunately lacks precision and it is moreover outdated. Important regional work on the genus has been carried out by Heim (1931) and Kühner (in Kühner & Romagnesi, 1953) in France; Alessio (1980) in Italy; Enderle & Stangl (1981) and Stangl & Enderle (1983) in Germany; Kauffman (1924), Stuntz (1947, 1954), and Grund & Stuntz (1968, 1970, 1975, 1977, 1980, 1981, 1983, 1984) in North America; and Horak (1978, 1979, 1980, 1981) in Australia and Asia.

Beschreibung: The nomenclatural status of the names of the species of Pholiota occurring in the Netherlands is investigated. Pholiota jahnii is proposed as a new species, and five new combinations are made, viz. P. populnea, P. conissans, P. lutaria, P. mixta, and P. scamba.

Beschreibung: Three coprophilous species of Cheilymenia resembling Lasiobolus are redescribed. Cheilymenia raripila is reported from Germany; C. insignis and C. pulcherrima are newly described from authentic material of the Crouan brothers. Cheilymenia hyalochaeta is considered to be a synonym of C. raripila.

Beschreibung: Additional collections to Symplocos goodeniacea Noot. are mentioned and S. costatifructa Noot and S. iliaspaiensis Noot. are newly described.

Beschreibung: Dictyoneura Blume (Sapindaceae) is a small Malesian genus. In this revision three species are described, one of which has not been named. Under one species a new subspecies is described.

Beschreibung: In one ‘flower’ a growing point occurred between a bract and its seemingly inverted carpel.

Beschreibung: The tropical ecosystem has been considered by many authorities as a stable vegetation type that, in some areas, has ‘existed uninterruptedly since a very remote geological time’ (Richards, 1952). The long term stability of rainforest ecosystems was first questioned when studies showed that there was a marked contraction of rainforest areas in the tropics during Pleistocene times (Flenley, 1979). Within New Guinea two major effects are reported: altitudinal fluctuation of the major vegetation zones at higher altitudes, as described by Flenley (1972), Hope (1976), Powell (1970), and Walker (1970); and a decrease in precipitation. As a result of the lower rainfall during the Pleistocene era (17,000—14,000 yrs BP) extensive areas of New Guinea were characterised by a very dry savanna type climate (Nix & Kalma, 1972). This is still reflected in the distribution of savanna elements in the present vegetation, in both lowland and lower montane areas. However, extensive disturbances are by no means restricted to the Pleistocene times. Studies in New Guinea show that the environment has been recently subjected to major disturbances caused by natural disasters. These phenomena are often easily plotted from aerial photographs and by using remote sensing techniques. An understanding of environmental instability is important, not only for the interpretation of the structure and floristics of the extant vegetation, but is also of major importance in the management of the tropical environment in New Guinea.

Beschreibung: A taxonomic revision of the genus Rapanea Aubl. in New Guinea, and partly in the adjacent areas (mainly the Moluccas and the Solomon Islands), comprising 22 species, 5 of which are new to science. A key to the species, full descriptions of all taxa, and an enumeration of the collections studied are given.

Beschreibung: Generic delimitations within the Rottboelliastrae Stapf and Coelorachidastrae Clayton (formal name) are revised. Coelorachis Brongn., Hackelochloa O. Ktze, Heteropholis C.E. Hubb., Ratzeburgia Kunth, and Rottboellia formosa R. Br, are to be included in Mnesithea Kunth. Heteropholis cochinchinensis (Lour.) Clayton and its variety chenii (Hsu) Sosef & Koning are varieties of Mnesithea laevis (Retz.) Kunth. Robynsiochloa Jacq.-Félix is to be included in Rottboellia L. f. The necessary new combinations, a list of genera and representative species, and a key to the genera are given. In the Appendix a new species of Rottboellia, R. paradoxa Koning & Sosef, is described from the Philippines. The enigmatic species Rottboellia villosa Poir. is transferred to Schizachyrium villosum (Poir.) Veldk., comb. nov.

Beschreibung: This monograph deals with the systematics and phylogeny of the genus Pyrrosia (Polypodiaceae). It is one of the results of the Polypodiaceae-project that is being carried out under the supervision of Prof. Dr. Hennipman (State University, Utrecht). With this treatment of Pyrrosia, the group of the Platycerioid ferns (sometimes regarded as a subfamily) will be completed. The total number of genera in this group is reduced to two: Platycerium and Pyrrosia. Other publications dealing with this group are Hennipman & Roos (1982), dealing with Platycerium; and Ravensberg & Hennipman (1986), dealing with the former genera Drymoglossum and Saxiglossum, now in Pyrrosia. Together with Hennipman & Ravensberg’s account this forms the first complete account of Pyrrosia. The genus has been subject to revision on a world-wide scale only once before (Giesenhagen, 1901). In that work, however, several species were omitted and the genera Drymoglossum and Saxiglossum were not included. After Giesenhagen’s monograph, Pyrrosia has been the subject of several regional studies, most notably Ching’s (1935), which deals with the species from the mainland of Asia including Japan and Taiwan. The African species were revised by Schelpe (1952), the Australian ones by Tindale (1961). Nayar & Chandra’s (1965) account of the species from India emphasizes the morphology rather than the taxonomy of the species treated.

Beschreibung: The taxa formerly referred to Drymoglossum and Saxiglossum are part of Pyrrosia. Of these 6 species the taxonomy is given and the phylogenetic relationships discussed. One monophyletic group could be recognized consisting of Pyrrosia heterophylla, P. niphoboloides and P. piloselloides (Drymoglossum p.p.).