Showing papers in "Naturwissenschaften in 1995"

Molecular phylogeny of metazoa (animals): Monophyletic origin

Abstract: The phylogenetic relationships within the kingdom Animalia (Metazoa) have long been questioned. Focusing on the lowest eukaryotic multicellular organisms, the metazoan phylum Porifera (sponges), it remained unsolved if they evolved multicellularity independently from a separate protist lineage (polyphyly of animals) of derived from the same protist group as the other animal phyla (monophyly). After having analyzed genes typical for multicellularity (adhesion molecules/receptors and a nuclear receptor), we present evidence that Porifera should be placed in the kingdom Animalia. We therefore suggest a monophyletic origin for all animals.

Three-dimensional models for humic acids and soil organic matter

Abstract: Humic substances and soil organic matter are one essential basis for life on earth, and the study of their structures is the aim of a fast-growing, interdisciplinary, scientific community, in particular in the environmental sciences. Modern methods of instrumental analytical chemistry such as analytical pyrolysis combined in an integrated approach with the wide range of standard chemical and biological techniques, have led to proposing a model structure for humic acids. Simultaneously, powerful software programs for computational chemistry and molecular modeling have become available and prompted our present work to develop model structures for humicand organomineral complexes as well as soil particles. The principal aims are to simulate, understand, and predict the trapping and binding of biological and anthropogenic substances in soils, and to follow geochemical processes at the nanochemistry level. The Chemistry of Soil Organic Matter

Specific enhancement of olfactory receptor sensitivity associated with foetal learning of food odors in the rabbit

Abstract: Evidence that odors can be learned prenatally further blurs the distinction between inborn and acquired responses and provides an unusual opportunity to investigate processes underlying the acquisition of information during the earliest stages of development (reviewed in [1]). This is particularly well illustrated by the development of food preference in the European rabbit (Oryctolagus cuniculus). Doe rabbits visit and nurse their young for only 3 to 4 min each day and usually wean them abruptly at about day 26 in preparation for the next litter. Under such circumstances, the young have little opportunity to learn what to eat from their mother by direct behavioral observation, but may do so indirectly by the preand postnatal acquisition of chemical information associated with her diet [2]. If pregnant does are fed aromatic juniper berries, which form part of the rabbit's natural diet, then at weaning, their pups demonstrate a preference for juniper, even if raised by a foster mother fed standard laboratory food and thus without postnatal juniper experience [2]. Although the development and expression of preferences certainly depends on central mechanisms, we speculated that such exposure learning, occurring in the apparent absence of conventional reinforces, might also be associated with the enhanced development of subpopulations of sensory cells or their receptors, and result in greater sensitivity to odors experienced during early life. Such enhancement seemed possible for several reasons: the clear evidence for prenatal odor perception accompanied by a substantial increase in the number of sensory cells, which occurs in the rabbit even postnatally [31, our experience that this increase is dependent on environmental stimulation during the first few days after birth [4], and the narrowing of the response profile of sensory cells reported to occur in the rat immediately before birth [5]. As a first test of this hypothesis, it was the purpose of the present study to establish whether prenatal experience of the mother's diet could be demonstrated behaviorally in newborn rabbits immediately after birth, and whether stimulus-specific, prenatal enhancement of sensitivity could be demonstrated postnatally by recording the electro-olfactogram (EOG), that is, the change in voltage across the olfactory epithelium in response to olfactory stimulation [6]. For this, pups were separated from their mother at birth and behavioral tests were conducted on the first postnatal day before the first suckling experience. All animals for which electrophysiological data were obtained continued to be tested each day until recording of the EOG either on days 1 3 or days 9-14. Domestic, chinchilla-breed rabbits (Chbb, Thomae, Biberach) were used. From mid gestation, 10°70 of the experimental does' daily ration of lab food (Altromin) was replaced by dried, commercially available juniper berries, whereas control does received the standard diet only. To establish whether learning had occurred, and thus that experimental litters had indeed been exposed to juniper, pups were tested for 3 min each day in a 22x32 cm arena containing three freshly chopped juniper berries beneath the wire-mesh floor at one end. The time pups spent on each side of the arena was recorded, and the number of trials in which one or the other side was preferred by control and experimental animals was compared using the chisquare test. Whereas control pups tended to avoid the juniper odor, pups from experimental mothers showed a clear preference for it, and throughout the 8-day test period spent more time in a greater number of trials on the scented side than controls (Fig. 1, p < 0.001). This was the case even on day 1, thus demonstrating the effectiveness of the prenatal treatment (p < 0.001). To investigate the influence of this odor experience on the functional properties of the olfactory epithelium, randomly selected pups were sacrificed and the nasal septum removed. To record the EOG, the epithelium was placed on a silver-plated spoon and kept moist with saline solution. The surface electrode, an agarand saline-filled glass pipette (30-40 ~tm 2~) containing a silver chloride wire, was positioned at the approximate center of the epithelium between the accessory olfactory nerves which served as landmarks. EOG potentials were monitored on an oscilloscope and a polygraph. The odorants juniper oil (V6gele, Stuttgart), and as a reference stimulus, isoamyl acetate (Merck) were delivered as a fivefold dilution series (1 ml vapor/600ms every 2rain) into a continuous, moisturized stream of oxygen (200ml/min) using a syringe olfactometer. At each dilution step, each odorant was delivered alternately, and three such dilution series, separated by a blank, were recorded for each animal. Stimulation with either odorant resulted in consistent, concentration-dependent amplitudes in both the juniper-exposed and control epithelia (Fig. 2). However, comparing the amplitudes for juniper with those for isoamyl acetate showed the juniper amplitudes to be relatively greater for epithelia from the exposed than from the control animals. When for each animal and dilution step, the relative dif-

Detection of model flowers by honeybees: The role of chromatic and achromatic contrast

Abstract: Spatial acuity depends on several factors, the most important of which are the sampiing density of the photoreceptor array, defined in the compound eye as the interommatidial angle A q~, and the contrast sensitivity of the eye, which is determined mainly by the size of the visual field of a single ommatidium (for more details, see [1, 21). Because a single ommatidium measures no more than the average intensity of the light absorbed in it, two objects, one dark and one bright, will only be resolved if they project onto two different (neighboring) ommatidia, and therefore the anatomical limit of spatial resolution is 2A~b. In the bee, A O is 1.4 ° in the vertical direction and 2.8 ° in the horizontal direction [3], and thus the limit of spatial resolution is 2.8 ° and 5.6 °, respectively. A q~ can be determined not only with the help of anatomical measurements but, in addition, in behavioral experiments using high-contrast moving gratings. A tethered-flying insect's optomotor response reverses its direction when the spatial period of the grating is smaller than 2AO. The values obtained using this method agree well with those inferred from anatomical studies (for refs., see [1]). However, the finest possible resolution, the limit of which is set by 2Aq~, can only be realized if the difference in intensity (i.e., the contrast) perceived by the two neighboring ommatidia is high enough to be detected. Intensity contrast between two adjacent stimuli, also termed intensity modulation (m), is defined as the ratio between the modulation amplitude and the mean intensity of the two stimuli. This ratio can also be expressed as m = ( I 1 I 2 ) l ( I 1 +I2) (1)

The significance of landmarks for path integration in homing honeybee foragers

Abstract: During their complex foraging trails, central place foragers often integrate distances traveled and angles turned to update continuously their estimation of home direction. This system, called path integration, allows them to head directly home even from an unfamiliar site [i]. Path integration has been particularly well studied in ants [21. Honeybees, Api s mellifera L., forced to deviate from straight lines between hive and a feeder by means of obstacles, indicate the actual compass direction of the target in their dances [3]. Thus, honeybees convey the results of path integration in their dance communication, but is it continually employed during flight? Our results indicate that path integration is weighted heavily when bees explore novel territory. On familiar ground, however, compass-guided flight vector instructions activated in a sequential fashion take precedence over the path integration system. In order to demonstrate path integration of foraging bees during long-distance orientation, the animals must fly \"voluntarily\" to a site that fulfils two simple prerequisites. (1) No landmarks visible from this point must indicate the direction of the hive, nor may the hive be directly visible. (2) The bees must have reached this point by a route that is not the straight line connecting the hive and the point in question. If animals manage to steer a direct course towards the hive from a place that meets these conditions, they must have estimated it from the length of path segments, and angles between these segments, flown prior to arrival at the particular site. To ensure condit ion (1), we established one Langstroth hive box containing a populous colony of European honeybees

Tracking of artificially matured eels (Anguilla anguilla) in the Sargasso Sea and the problem of the eel's spawning site

Abstract: Since Schmidt's classical work on Anguilla anguiIla, the spawning of European eels in the Sargasso Sea has been inferred from larval distributions only [1, 2]. \"There is no doubt that the occurrence of larvae smaller than 7 mm and even that of the larger larvae is congruent with the spawning area of the adults\" [2, 3]. Although the Sargasso Sea is an extremely deep water body of more than 5000 m depth, the spawning of eels has been assumed to occur in relatively shallow waters [1, 3-7] . The warm surface water of the Sargossa Sea overlies the North Atlantic central water mass down to 150-200m depth [5, 7]. The 18-19°C isotherm at 200-300 m is considered to be the boundary of the spawning depth [5]. Indirect evidence favors this hypothesis (summary in [7]). For example: the optimal temperature for artificially induced gonadal maturation and spawning behavior is 20-23 °C, This temperature occurs at about 100-200 m depth in the southern Sargasso Sea. Migrating eels prefer a temperature of about 17°C [8]. They undergo dramatic changes in body coloration (Fig. 1), eye diameter, and visual pigments adapted for vision in dim blue light of the photic zone. The length of the rete mirabilis to fill the swim bladder suggests migration between 100-200 m. Here, we present further evidence for shallow-water spawning and reinvestigate the distributional records of the smallest leptocephalus larvae, which are the most likely candidates for the nearest spawning site. The occurrence of the smallest larvae is concentrated in the sourthern Sargasso Sea. A numerical simulation model of the North Atlantic circulation provides evidence for a southern route of migrating silver eels which probably spawn south near 20°N outside of the earlier presumed spawning area. During the Sargasso Expedition 1993 with the German research vessel Poseidon, we released two hormon-treated, sexually mature silver eels in order to record a possible depth preference which could be taken as further evidence for shallow-water spawning. Earlier, Tesch [4, 7] released four hormon-treated eels in the Sargasso Sea which were not yet fully mature. They descended to a maximum depth of 700 m, indicating migration en route to the spawning grounds rather than movements at or near the spawning sites. Three months prior to our tracking experiments, the eels were treated weekly with a carp pituitary extract. Four eels were transported on board the Poseidon and kept in an aerated water container. During the voyage, repeated water changes allowed slow temperature adaptation to a maximum 23 °C, the surface temperature of the Sargasso Sea and presumed trigger of spawning. Two eels having 795 and 890 mm total length died after arrival to the Sargasso Sea. Both eels showed all adaptations accompanying spawning migration. They had increased eye diameters (10.0-10.5mm), heavily swollen abdomens, and countershading (Fig. 1). Big oocytes of maximal 1.01.1 mm (measurements after fixation with 4% formalin) were squeezed from the eel's genital openings in parcels. Both eels were at a very advanced stage of sexual maturation and probably ready to spawn (Strelow, pers. commun.). The eels used for the tracking experiments were of similar size and gonadal maturation. Both were tagged with miniature pressure-sensitive ultrasonic VEMCO transmitters (VEMCO 9082, 69.0kHz, VEMCO 9081, 65.5 kHz) and released on March 12 and 20 at the presumed peak of spawning at 4300 and 6000m depth, respectively, at the following positions: eel No. I at 25 ° 15.00' N, 62 ° 25.64' W; eel No. 2 at 29 ° 31.82' N, 64 ° 05.92' W. Temperature and other oceanographic parameters were automatically recorded using CTD and XBT probes from aboard the mothership. The eels were tracked from an inflatable, the position of which was followed by a GPS navigational system. After surface release both eels were filmed by a diver. Probably in response to a negative phototaxis, both eels descended vertically with a maximum speed of V= 0.63 cm/s. Eel 1 stopped at 250m and remained with short vertical excursions at an average depth of 269 m. Eel 2 descended directly to a maximum depth of 302 m, ascended shortly afterwards to 160m, and remained at around 250m (Fig. 2). At their target depth, both eels were in temperatures between 18.718.8°C. Eel 1 remained during 4h of tracking almost on the spot. It traversed a distance of approximately 560 m only in a southeasterly direction. Eel 2 was followed over 7 h and traveled over 10.6 km on an almost straight SW course. During the afternoon, this eel slowly migrated upwards (Fig. 2), a behavior also reported for migrating silver eels tracked near the European continent [9].

Thelytokous parthenogenesis and dominance hierarchies in the ponerine ant,platythyrea punctata

Abstract: i. Frisch, K. von: The Dance Language and Orientation of Bees. Cambridge: Belknap 1967 2. Heran, H.: Z. vergl. Physiol. 38, 168 (1956) 3. Scholze, E., et al.: Naturwissenschaften 51, 69 (1964) 4. Goller, E, Esch, H.: ibid. 77, 594 (1990) 5. Esch, H., et al.: J. Comp. Physiol. B 163, 626 (1994) 6. Wehner, R., in: Animal Homing, p. 45. London: Chapman & Hall 1992 7. Lehrer, M., in: The Behaviour and Physiology of Bees, p. 185. Wallingford: CAB International 1991 8. Braeuninger, H.D.: Z. vergl. Physiol. 48, 1 (1964) 9. Ronacher, B., et al., in: Goettingen Neurobiology Report 1994, p. 456. Stuttgart-New York: Thieme 1994

Formation of carbon monoxide by photolysis of dissolved marine organic material and its significance in the carbon cycling of the oceans

Abstract: The importance of carbon monoxide (CO) as a major sink for the OH radical in the atmosphere is well established [1]. However, comparatively little is known about its role in the world oceans. In surface ocean waters, dissolved CO is typically supersaturated with respect to atmospheric equilibrium, and the dissolved concentration varies diurnally with light intensity [2-4]. It has, therefore, been, assumed that the formation of CO in seawater is due to photooxidation of dissolved organic carbon (DOC). Recent oceanographic studies have further implied that CO may occupy a key position in the oceanic carbon cycling as an intermediate in the photochemical mineralization of marine-dissolved organic matter (DOM) which is resistant to biological decomposition. Among all identified photoproducts of DOM, CO is a predominant species and accounts for about 70_+ 10% of total carbon transfer from DOM to the identified low-molecular-weight carbon products [5-7]. In this paper we present experimental results which first show a strong correlation between photochemical formation of CO and dissolved organic carbon (DOC) in seawater, and then estimate the quantity of the global photochemical production of CO in the oceans as well as its significance in global oceanic carbon cycling. During cruises to the Gulf Stream (May, August, 1991; August, 1992) and to the southwestern Sargasso Sea (August, 1989), seawater samples were collected off the southwest coast of Florida and in oligotrophic waters. Surface samples were taken every 30 rain while the ship was underway and every 60 min when the ship was on station, from an all-Teflon, bow-mounted pumping system permanently installed in the RV Columbus Iselin. The samples were filtered (0.45 ~tM) and the absorbance at 350 nm was measured immediately before irradiation. For measurement of DOC, seawater samples were stored refrigerated in clean glass bottles and returned to the laboratory for analysis using a Shimadzu TOC 5000. Irradiation experiments were carried out within 90 min of sampling for the samples from the cruise of August

Evidence of Contamination in PCR Laboratory Disposables

Abstract: tration in Richtung der sauren Komponenten, wobei Alkalinitfit (besonders HCO3), der L0sung verlorengeht. Wie die Analysen der Schneeschmelze 1994 zeigen, ist ein solcher Gewfisserzustand bei Erniedrigung der Konzentration mobiler Anionen durchaus reversibel. Somit finden die eingangs diskutierten Hypothesen keine Bestgtigung. Aus der Aciditfit und der Kationenzusammensetzung der Bachw~tsser bei Schneeschmelze 1994 l~tgt sich kein irreversibler Verlust an S~urepufferkapazit~tt der Bodenfestphase erkennen. Vielmehr gehen die beobachteten hydrochemischen Verfinderungen auf Kationenaustauschprozesse zurgck, deren AusmaI3 und Richtung direkt von den Konzentrationen der mobilen Anionen SO~-und NO3abh~tngt. W~thrend bei SO~die riicklfiufige Deposition bestimmend sein dOrfte, spielen bei NO 3 die witterungsabh~tngigen internen Umsetzungen im Okosystem die Schltisselrolle. Unsere Ergebnisse sttitzen somit nicht die Annahme einer nachlassenden N-Retention, wonach es dutch ,,Waldsterben\" wegen hoher N-Deposition zu einem generellen Anstieg der NO~-Konzentrationen in Waldgew~issern gekommen sein soll (z. B. Fichtelgebirge [41).

Nonrandom search geometry in subterranean termites

Abstract: [Extract] Studies of the organization of search in ants suggest that individual and colonylevel patterns are related to foraging ecology and may be adaptive [1, 2]. The organization of search in termites has received far less attention, in part because of their cryptic, subterranean foraging habits. Search in subterranean termites involves the construction of a gallery system, a series of branching tunnels in the soil that brings termites into contact with food. The organization of the gallery system might reflect the efficiency of colony search. In this paper we describe the nonrandom colony- level search pattern of the subterranean termite Reticulitermes ftavipes (Kollar), and suggest that it may be organized to minimize search redundancy.

Action potential-like activity found in fungal mycelia is sensitive to stimulation

Abstract: Received June 1 and August 17, 1994 1. P6rschmann, J., Stottmeister, U.: Chromatographia 36, 207 (1993) 2. Frimmel, E H., Christman, R,E (eds.): Humic Substances and Their Role in the Environment. Chichester: Wiley 1988 3. Perdue, E.M., Gjessing, E.T. (eds.): Organic Acids in Aquatic Ecosystems. Chichester: Wiley 1990 4. Kopinke, E-D., P6rschmann, J., Stottmeister, U.: Environ. Sci. Technol. (submitted) 5. Wershaw, R.L.: ibid. 27, 814 (1993) 6. Hawthorne, S.B., Miller, D. J., Pawliszyn, J., Arthur, C.L.: J. Chromatogr. 603, 185 (1992); Potter, D.W., Pawliszyn, J.: Environ. Sci. Technol. 28, 298 (1994) 7. Kopinke, E-D., Remmler, M.: in preparation 8. Daylight Chemical Information Systems, Inc., Irvine, CA, USA: Pomona 92 Database 1992; Howard, T.H.: Chemfate Database. Syracuse Research Corp. 1993

Ant queens deposit pheromones and antimicrobial agents on eggs

Abstract: Nordrhein-Westfalen) served as additional references. Flow-cytofluorometric determination (Partec CA II cytometer, Mfinster, Germany) of relative DNA contents of cell nuclei was selected as additional diagnostic assay. The relative genome sizes of salmonids found in tissues of yolk-sac larvae stained with the DNAspecific fluorochrome 4,6-diamidino-2phenylindole differ sufficiently for species differentiation [3, 4, 9, 12]. Again, trout larvae from the breeding stock indicated above served as internal references during flow cytometry. Both diagnostic approaches, whether based on single-locus markers or total genome size, demonstrated that pure-bred offspring of naturally reproducing Atlantic salmon hatched in affluents of the Rhine river in 1994. Our previous finding of F1 hybrids between S. salar and S. trutta in stock bound for restocking the Rhine with Atlantic salmon [6] serves as a warning to continue population-genetic monitoring of the recolonizing salmon population, in order to ensure that reintroduction projects performed to support reappearing stocks are not detrimental to the requirements of species conservation.

Neurobiologie der Wortverarbeitung

Abstract: Neurobiological mechanisms underlying language functions can be modeled in the framework of Hebb's cell assembly theory. According to this approach, meaningful words, but not meaningless pseudowords, have a cortical representation in strongly coupled ensembles of neurons distributed over wide cortical areas. Cell assemblies with different cortical topographies can be assumed for different word types. These hypotheses give rise to empirical predictions that can be tested in behavioral and electrophysiological experiments with healthy and neurologically impaired subjects. Results of a series of experiments providing support for the above assumptions are summarized.

Visible and UV coloration in birds: Mie scattering as the basis of color in many bird feathers

Abstract: (Fig. 1D) or global ones (Fig. 1E). Spontaneous shape preferences of honeybees have led to similar conclusions [7]. It should be noted that prel iminary experiments on the lurcher indicate that specific dummies (e.g., those with two compact orange dots, see Fig. 1 E) may be as attractive or even more attractive than what appears to human observers to be most lurcherlike. We are presently investigating the role of further shape parameters by systematically varying them, to determine which individual features, or combinations of such, are the most el'fective in the task of pat tern discrimination. In addition, we plan to employ electrophysiology in order to f ind the neuronal mechanisms underlying the observed choice behavior.

Sequential stimulation of guinea pig cerebellar cortex in vitro strongly affects Purkinje cells via parallel fibers

Abstract: The cortex of the cerebellum is distin­ guished from other cortices by its large population of thin unmyelinated fibers (the parallel fibers) which reach from each point in the cerebellar cortex a few millimeters to the left and to the right [4, 8, 14). Parallel fibers originate from a T­ shaped bifurcation of ascending axons of granular cells. These relay signals from one of the main systems of afferent fibers, the mossy fibers, to the Purkinje cells. The latter are the only output cells of the cerebellar cortex. The parallel fibers con­ tact the flattened dendritic trees of the Purkinje cells by synapses which have been shown to be excitatory [6). Purkinje cells receive input from nearly 200000 parallel fibers [8). These synapses are the large majority of synapses in the cerebellar cortex. Parallel fibers also con­ tact the dendrites of stellate and basket in­ terneurons, the inhibitory axons of which are oriented at right angles to the parallel fibers. The dispersion of signals from each parallel fiber onto rows of Purkinje cells situated at various distances from the origin has been interpreted in various ways. One suggestion was that the whole arrangement transforms time intervals in­ to space intervals and vice versa, and therefore acts as a set of delay lines [3). However, the delays produced by in­ dividual parallel fibers are too short to be of any use in motor control, a function which is commonly attributed to the cerebellum. A different interpretation proposed for the system of parallel fibers is that of a tissue globally conducting signals at a fixed speed [2). In fact, the anatomy suggests that an ordered sequential input in the mossy fiber system "moving" across the cerebel­ lar cortex in the direction of the parallel fibers at their speed of conduction should produce something like a tidal wave of spikes in the parallel fiber system, i.e., a very strong excitation of the target neurons (Fig. 1). This may explain why other authors, working with static input from the mossy fiber system [1, 16, 17), found so little in­ fluence of parallel fibers on Purkinje cells that the effectiveness of parallel fiber synapses was all together called in ques­ tion [1, 12, 13]. I tackled this issue experimentally using an in vitro slice preparation of guinea pig cerebellar cortex (Figs. 2, 3). Acute slices were prepared from adult guinea pigs (500-600 g). Animals were decapitated under ether anesthesia and the cerebellum was quickly excised. Slices were cut by means of a vibratome (Campbden, UK)

Homoplastic rearrangements of insect mitochondrial tRNA genes

Abstract: O., Bestmann, H.J.: J. Chem. Ecol. 13, 1299 (1987) 8. Ahlquist, L., Bergstr6m, G., Liljenberg, C.: Prog. Chem. Fats Lipids 16, 231 (1978) 9. Attygalle, A.B., Morgan, E.D.: Angew. Chem. 100, 475 (1988) 10. Klinge, S., Demuth, M.: Synlett 1993, 783 11. Schneider, D., L.: Z. vergl. Physiol, 40, 5 (1957) 12. Kern, E, Bestmann, H.J.: Naturwissenschaften 80, 424 (1993) 13. Bergstr6m, G., Kullenberg, B., St/illbergStenhagen, S.: Chem. Scripta 4, 174 (1973) 14. Svensson, B.G., Bergstr6m, G.: Insectes Soc. 24, 213 (1977) 15. Bergstr6m, G., L6fquist, J.: J. Insect Physiol. 19, 877 (1973)

Non-size-based morphological castes in a social insect

Abstract: D.H.: J. exp. Biol. 181, 49 (1993) 9. Lighton, J.R.B., Feener, D.H.: Nature 342, 174 (1989) 10. Nielsen, M.G., Jensen, T. E, Holm-Jensen, I.B.: Oikos 39, 137 (1982); Lighton, J. B. R., Bartholomew, G.A., Feener, D.H.: Physiol. Zool. 60, 524 (1987): Bartholomew, G.A., Lighton, J. R.B., Feener, D.H.: ibid. 61, 57 (1988); Duncan, ED., Lighton, J.R.B.: ibid. 67, 190 (1994) 11. Nielsen, M. G., Baroni Urbani, C.: Physiol. Entomol. 15, 441 (1990)

New data on the dimensions of Brachiosaurus brancai and their physiological implications

Abstract: There are highly divergent data on the body m a s s (mb) of Brachiosaurus (B.). The range of the body-mass estimations lies between 14900 and 102000 kg for this giant dinosaur [1-6] . This is mainly due to the fact that different specimens and varying techniques are used for the volume (V) estimations, such as equations from the circumferences of femur and humerus [4] or from the volume of models [5]. The precise determination of Vis important for calculating the body surface area (SA) as well as for allometric equations, which are often based on Mb. Herewith, we present a photogrammetric method to determine the metrical dimensions of giant sauropods such as B. The data presented here are based on the skeleton of B. brancai from the Upper Jurassic of Tendaguru (East Africa, Tanzania), mounted and exhibited at the Museum of Natural History in Berlin (Germany). The major part of the skeleton belongs to one single specimen of B. brancai recovered from the Middle Saurian Bed at Tendaguru. The tail originates from another individual of the same species of similar size found in the Upper Saurian Bed. In addition, skeletal remains of B. brancai excavated in different sites in the surroundings of the Tendaguru hill were used for the mounting, partly original and partly modeled. The presacral vertebral column (cervicals, dorsals) and the skull have been replaced by plaster copies modeled from originals of the main skeleton due to their extreme fragility and weight. The right shoulder blade, four dorsal ribs, and some bones of the left forefoot have been modeled in plaster according to counterparts of the other body side. Some missing elements are substituted by bones belonging to individuals of the same size such as the right ilium, the right ischium, and the left lower leg. Other missing items have been replaced by originals (e.g., left femur) or copies of bones from different-sized animals (e.g., sacrum, most hindfoot bones). At the very end of the tail four small pieces were added. Like the missing first caudal vertebra, most of the hemapophyses (chevrons) are plaster imitations [6]. As can be seen in Fig. 1, we divided the presumable shape of B. brancai into XI parts. Each part was separately calculated and the Vi-xi are given in Table 1. From the V found, the Mb was calculated assuming a density of 1000 kg per m 3 tissue [5, 7]. On the basis of the above findings, we investigated further whether the presumable organ volumes derived by allometric equations could be fitted into the anatomical dimensions given by the skeleton. The advantage of the photogrammetrical approach is that when the values are taken from a specimen, the complete shape of the animal is stored in the computer. This allows later derivation of other forms and dimensions, which is almost impossible from a model. In the case of a small model being built from the data and later becoming enlarged, the smallest deviation is multiplied by a factor of 10-50 depending on the size of the model. Therefore, regardless of the size of a model, it is defined by these exact basal metric values. The anatomical data of B. brancai derived by stereophotogrammetry and the presumable physiological data calculated after equations given for endotherms are summarized in Table1, Table2, and Fig. 2. According to these, the Mb of B. braneai is ca. 74420 kg (skeleton 11480 kg). Accordingly, the M b estimations in [1] are similar to our findings, whereas those in [2, 4 6 ] are far too low. It is not clear whether the estimation in [3] for B. refers to the Berlin specimen. If so, it is far too high. The S A (Table 2) was found to be at least (without any skin-

Effect of long-term cultivation on the chemical structure of soil organic matter

Abstract: Soil organic matter (SOM) is central to the maintenance of soil quality. In a longterm crop rotation study established in 1910 in western Canada, net SOM losses were equivalent to < 24% of the original concentration after cultivating a Typic Haploboroll for 80 years. Organic C (Corg) declined rapidly during the first 12 years of cultivation, and at a lower rate thereafter [1]. As the exact mechanisms governing SOM stabilization and so preventing complete microbial decomposition are largely unknown, there is a need for more research in this area. In addition, the chemistry of SOM and its role in soil quality are largely unknown. The objectives of this study are to examine the effects of cultivation on SOM quality and to elucidate mechanisms of SOM stabilization. Soil samples from a Typic Haploboroll were taken from a long-term crop rotation study established in 1910 at Lethbridge, Alberta. Historic information on tillage practices, wheat varieties, plant yield, and climate was reported earlier [2]. Soil samples were taken in 1910 from the A horizon after breaking the native grassland (native samples) and in June 1990 from the A horizon of the wheat-fallow, non-fertilized rotation (cultivated samples). Total C was determined by dry combustion in a Leco furnace (model CHN-600). Inorganic C was determined by measuring CO 2 evolved after hot digestion with 6 N HC1 [3]. The Corg content was determined by difference. Some physical and biochemical soil properties are shown in Table 1. Detailed descriptions of temperature-resolved pyrolysisfield ionization mass spectrometry (PyFIMS), the integration of single spectra into summed spectra and the assignment of signals to seven groups of SOM components, have been published earlier [4-8] . Assays for urease, phosphatase, and dehydrogenase were carried out using standard methods [9, 10]. The patterns of Py-FIMS spectra for the native grassland soil and cultivated samples were intense and quite different (Fig. 1). Qualitative differences in higher molecular weight mass ranges and signal density, particularly between m/z 110 and 300 where practically each nominal mass is occupied, and high complexity of the signal pattern, clearly distinguish the native from the cultivated sample. Dramatic chemical differences between the two soils are observed when the PyFIMS spectra are normalized to counts × 104/mg sample. Peak intensities in the Py-FI mass spectrum of the native soil (Fig. 2 a) are in the range of 104counts/rag for the signals between m/z 19 and 110 and decrease to 103 counts at higher mass range. In comparison, peak intensities for the cultivated sample (Fig. 2b) are only 2000 counts/rag in the low mass range ( < m / z 110) and even lower at higher masses. According to

Color and Angular Orientation in the Discrimination of Bilateral Symmetric Patterns in the Honeybee

Abstract: subplates, 30 cm in diameter, which were inserted in the larger round plate. The three subplates could be rotated independently. Each of the 12 sites was equipped with a microphone and a reference microphone (24 in total). The microphones were used for automatic detection of the approach flight of a bee during the test procedure: they had frequency thresholds adjusted to detect the bees' flight and intensity thresholds such that choices were recorded from a flight distance of 5 cm. The signals of the microphones were A/D converted and monitored by a computer that automatically stored the bees' choices at a resolution of 11 ms. The stimuli were placed on the microphone capsules and five thin perforations were made in the center of the cardboard forms to record the bees' choices.

Hydrological changes of the amazon during the last glacial-interglacial cycle in Central Amazonia (Brazil)

Abstract: In the past, Quaternary paleoclimatologica1 and paleoenvironmental reconstructions concentrated regionally on the northern mid-latitudes. This contrasts with the efforts and the state of knowledge on low-latitude regions. One such example is the huge tropical forest area of the Amazonian lowlands, which represents an important terrestrial pool of carbon. According to some authors, this pool was drastically reduced during the last main glacial phase due to a decrease in precipitation. Based on biogeographical, palynological, and sedimentological investigations, a savannah-type vegetation with isolated forest refugia was postulated [13], which is doubted by others [4-6]. This controversy suffers partially from the lack of data from lake sediments of Central Amazonia, documenting paleoenvironmental information of this period. This work presents a new approach investigating Central Amazonia for potential sites containing Holocene and Pleistocene sedimentary sequences by using high resolution (3.5 kHz) sonic profiling. As a first step, we report on data obtained in selected Ria lakes (Rio Preto da Eva, Lago Manacapuru) of Central Amazonia (Fig. 1), providing new data on past hydrological changes of the Amazon based on acoustic units recognized in these tributaries. Ria lakes are a characteristic morphological feature of the recent Amazon river system. The term Ria lake was assigned for the drowned parts of tributaries [7] with little or no suspended load (\"clear or black water rivers\"). The formation and/or shaping of the valleys has been linked to low sea level stages during glacial maxima when the river beds of the Amazon and its tributaries were deepened due to erosion [8]. The subsequent transgression during the postglacial rise of the sea level finally led to the filling of the

Sorption behavior of anthropogenic humic matter

Abstract: Humic organic matter is a catchall term for persistent biopolymers occurring in soil, sediments, and water. It is known to influence the transport, the bioavailability, and the toxicity of organic and inorganic pollutants profoundly. In addition to natural pathways, humic organic matter may also be formed on the basis of organic compounds arising from human activities. Typical examples include dumps and dump-site leaching water. Our interest is focused on a pond for wastewater from a carbonization plant in the German state of Saxony-Anhalt [1]. The coal wastewaters were originally pink, and turned dark brown as a result of autooxidation processes of organic pollutants including phenols, aromatic nitrogen bases, and PAHs. We designated these dark polymers as anthropogenic humic matter. The anthropogenic humic and fulvic acids are deposited in the sediments at the bottom of the pond and are dissolved colloidally in the water. In contrast to the knowledge about natural organic matter, which was frequently been the subject of interest (see [2, 3] and literature cited therein), the knowledge relating to both the structure and the complexing behavior of anthropogenic humic matter is rather poor. Beyond basic scientific interest, the investigation of the complexing behavior of such anthropogenic humic matter with regard to pollutants may be helpful in developing remediation strategies for contaminated sites. Therefore, our investigations aim to characterize the structure of the humic matter by combining several chromatographic (HPLC, GPC, pyrolysis-GC/MS) and spectroscopic (FTIR, 1H-NMR, ICPMS, thermogravimetry-MS) methods. Furthermore, we ~ire interested in their sorption behavior towards selected organic pollutants in water [4]. Surprisingly, anthropogenic and natural humic materials do not differ significantly in their sorption behavior towards nonpolar hydrocarbons (cf. Fig. 1). Until now, the description of sorption phenomena by physicochemical parameters has been considered impractical. However, by modifying the Flory-Huggins theory we succeeded in obtaining a mathematical expression describing the connection between the lipophilicity of a solute i, expressed by its octanol/water partition coefficient Kow, and its sorption coefficient on organic matter KoM:

From molecules to materials — a novel route for the synthesis of advanced ceramics

Abstract: The present contribution reports on the synthesis of novel ceramic materials from molecular precursors like inorganic-organic hybrid polymers. This procegs, denoted as polymer pyrolysis, was developed in the mid-1970s for the fabrication of inorganic fibers made of silicon carbide (SIC). Current investigations and results in this field of research are highlighted. The main topics reviewed are related to the synthesis of appropriate polymeric ceramic precursors, especially for the preparation of multicomponent materials, the processing of the molecular compounds to ceramic components, and finally to the characterization of the material properties.

All- trans geranylgeranyl acetate and geranylgeraniol, recruitment pheromone components in the dufour gland of the ponerine ant Ectatomma ruidum Pheromones, 100 [1]

Abstract: Theodor Boveri Institut, Lehrstuhl ftir Verhaltensphysiologie und Soziobiologie der Universit~it, D-97074 Wtirzburg, Germany one major peak and a few minor peaks (Fig. 1). The mass spectrum of the major component 1 (approx. 140 ng per gland) is shown in Fig. 2. This spectrum is similar to that of the diterpene geranylgeraniol [8]. Retention time and molecular ion (M + 332) suggested that 1 represents the corresponding acetate. Investigating the minor compounds, we also found geranylgeraniol (2). In contrast to /, 2 occurs only in traces (1 10 pg) in the Dufour's gland of E. ruidum. By micropreparative gas chromatography [9] on a 2 m × 4 mm glass column SE 52, different fractions of the E. ruidum Dufour's gland extract were split, trapped, and tested by a bioassay, following the procedures described in [4]. Only the fraction collected between the retention times of heneicosane (RI 2100, 32.79 min) and