Acoustical signals in the dance language of the giant honeybee,Apis dorsata

Summary Acoustical signals emitted by dancing bees have recently been shown to transmit information about the location of food sources in the western honeybee, Apis mellifera. Towne (1985) reported that in the Asian honeybee species Apis dorsata, which builds a single comb in the open under overhanging rocks or tree branches, sound signals were not emitted by the dancers. This led to the conclusion that acoustical communication is restricted to bees that nest in the dark, like A. mellifera. Here we show that in fact A. dorsata produces dance sounds similar to those emitted by A. mellifera, and that these acoustical signals contain information about distance, direction and profitability of food sources. The acoustical transfer of information has thus evolved independently of nesting in dark cavities. The significance of nocturnal activity in Apis dorsata for the evolution of sound communication is discussed. Correspondence to: W.H. Kirchner     

Umbilical cord haematoma as a complication of intrauterine intravascular blood transfusion

Between October 1985 and February 1989, 49 ultrasound-guided intravascular fetal blood transfusions were performed in 16 patients (14 with rhesus (Rh) isoimmunization, 2 with non-immunologic hydrops fetalis (NIHF)). As an intra-operative complication, perivascular haematoma of the cord occurred in three patients (7 per cent). In two cases, fetal bradycardia necessitated delivery by Caesarean section at 30 and 32 weeks' gestation, respectively. In the third case, fetal bradycardia developed during transfusion, at 31 weeks' gestation, but normalized within 3 min. The baby was delivered as planned at 36 weeks of gestation, after another transfusion at 34 weeks. Dislodgement of the needle tip into perivascular tissue, caused by sudden fetal or maternal movements, is the reason for this complication. The haematoma develops as a result of delayed recognition and continuous transfusion into Wharton' s jelly. Cord haematoma may be diagnosed in time by continuous ultrasound imaging, as illustrated in case 3. To minimize the risk of needle dislodgement during transfusion, sedation of the mother and complete immobilization of the fetus by injecting a short-acting muscle relaxant into the umbilical vessel are recommended.     

Prenatal diagnosis and perinatal management of a fetal ovarian cyst

A case of a prenatally diagnosed fetal ovarian cyst is presented. The pregnancy was complicated only by polyhydramnios, and some degree of fetal bowel obstruction could be recognized on sonogram. The newborn was delivered vaginally in the 39th week of pregnancy, and the cyst was removed by laparotomy on the day of the delivery. The etiology of this rare fetal condition is unknown.     

Die Titicaca-See-Region auf dem Altiplano von Peru und Bolivien und die Folgen eingeführter Fische für Wildarten und ihren Lebensraum

In the course of a long-term case study (since 1960) the interaction between different exotic fish (salmonids, atherinids) on the endemic ichthyofauna (genusOrestias: Cyprinodontidae) introduced to the interandean basin of Lake Titicaca was observed. The contribution deals not only with the actual consequences which endanger endemic species but also the socio-economic effects on the native Indian population, both causing further ecological problems in the region of concern.     

Longevity of granular iron in groundwater treatment processes: changes in solute transport properties over time

Although progress has been made toward understanding the surface chemistry of granular iron and the mechanisms through which it attenuates groundwater contaminants, potential long-term changes in the solute transport properties of granular iron media have until now received relatively little attention. As part of column investigations of alterations in the reactivity of granular iron, studies using tritiated water (3H(2)O) as a conservative and non-partitioning tracer were periodically conducted to independently isolate transport-related effects on performance from those more directly related to surface reactivity. Hydraulic residence time distributions (HRTDs) within each of six 39-cm columns exposed to bicarbonate solutions were obtained over the course of 1100 days of operation. First moment analyses of the data revealed generally modest increases in mean pore water velocity (v) over time, indicative of decreasing water-filled porosity. Gravimetric measurements provided independent estimates of water-filled porosity that were initially consistent with those obtained from 3H(2)O tracer tests, although at later times, porosities derived from gravimetric measurements deviated from the tracer test results owing to mineral precipitation. The combination of gravimetric measurements and 3H(2)O tracer studies furnished estimates of precipitated mineral mass; depending on the assumed identity of the predominant mineral phase(s), the porosity decrease associated with solute precipitation amounted to 6-24% of the initial porosity. The accumulation of mineral and gas phases led to the formation of regions of immobile water and increased spreading of the tracer pulse. Application of a dual-region transport model to the 3H(2)O breakthrough curves revealed that the immobile water-filled region increased from initially negligible values to amounts ranging between 3% and 14% of the total porosity in later periods of operation. For the aged columns, mobile-immobile mass transfer coefficients (k(mt)) were generally in the range of 0.1-1.0 day(-1) and reflected a slow exchange of 3H(2)O between the two regions. Additional model calculations incorporating sorption and reaction suggest that although changes in HRTD can have an appreciable effect on trichloroethylene (TCE) transformation, the effect is likely to be minor relative to that stemming from passivation of the granular iron surface.     

Response of magnesium-deficient saplings in a young, open stand of Picea abies (L.) Karst. to elevated soil magnesium, nitrogen and carbon

A decline in a Picea abies L. (Karst.) stand in the Fichtelgebirge, NE-Bavaria, FRG has been attributed to a nutritional disharmony-a seasonal imbalance between a high supply of nitrogen, caused by high nitrogen deposition, and a low supply of soil magnesium, caused by soil acidification (Oren et al., 1988a). The nutritional disharmony hypothesis was tested on ten-year-old P. abies saplings in an adjacent stand growing on identical soil. The supply rate of magnesium relative to nitrogen was continuously increased or decreased during three successive growing seasons. Increasing the nitrogen or carbon supply resulted in a small increase in foliar nitrogen concentrations. Magnesium or carbon addition slightly raised the concentration of magnesium in the foliage. Reduction in crown leaf-area did not result in any appreciable changes in nutrient concentrations. Increased N supply decreased foliar Mg concentrations. In spite of the changes in the nutritional status of the needles, gas-exchange rates, pigment concentrations, needle characteristics and growth of twigs and stems did not differ among treatments. It appears that the growth of saplings was unimpaired at the foliar magnesium concentration at which the growth of adjacent mature trees was reduced. Moreover, it was not possible to promote nutritional disharmony in the saplings, including those receiving three times the annual nitrogen input. The study demonstrates that in young, relatively open stands of P. abies, much of the deposited nitrogen is not absorbed by the roots of saplings. Thus, the conceptual model of nutritional disharmony cannot explain forest decline if nitrogen uptake does not increase with deposition. Identifying the processes which control the uptake relative to the supply of all nutrients, and quantifying the rates of nutrient uptake are essential steps in using the conceptual model to explain specific decline symptoms.     

Ozone exposure

Increased tropospheric ozone concentrations cause damage to both human health and the environment. To assess the exposure of forest areas and selected tree species to ozone, it is necessary to calculate the ozone exposure distribution. The present article describes the application of an ozone interpolation model to the calculation of the ozone exposure distribution in combination with forest inventory data. The exposure of forest regions to ozone was assessed by means of an AOT40 map (accumulated ozone exposure over a threshold of 40 ppb). The calculation was performed by hourly running of the model during the summer term and accumulation of the patterns that exceeded 40 ppb. The exposure of the primary Austrian tree species to ozone can be assessed due to the spatial relation of ozone exposure and tree species patterns. This spatial relation also allows the verification of assumptions concerning ozone-related tree damage.     

Identification of surrogate compounds for the emission of PCdd/F (I-TEQ value) and evaluation of their on-line real-time detectability in flue gases of waste incineration plants by REMPI-TOFMS mass spectrometry

Correlations between products of incomplete combustion (PIC), e.g., chloroaromatic compounds, can be used to characterise the emissions from combustion processes, like municipal or hazardous waste incineration. A possible application of such relationships may be the on-line real-time monitoring of a characteristic surrogate, e.g., with Resonance-Enhanced Multiphoton Ionization-Time-of-Flight Mass Spectrometry (REMPI-TOFMS). In this paper, we report the relationships of homologues and individual congeners of chlorinated benzenes (PCBz), dibenzo-p-dioxins (PCDD), dibenzofurans (PCDF) and phenols (PCPh) to the International Toxicity Equivalent (I-TEQ) of the PCDD/F (I-TEQ value) in the flue gas and stack gas of a 22 MW hazardous waste incinerator (HWI). As the REMPI detection sensitivity is decreasing with the increase of the degree of chlorination, this study focuses on the lower chlorinated species of the compounds mentioned above. Lower chlorinated species, e.g., chlorobenzene (MCBz), 1,4-dichlorobenzene, 2,4,6-trichlorodibenzofuran or 2,4-dichlorophenol, were identified as I-TEQ surrogates in the flue gas. In contrast to the higher chlorinated phenols, the lower chlorinated phenols (degree of chlorination <4) were not reliable as surrogates in the stack gas. The identified surrogates are evaluated in terms of their detectability by REMPI-TOFMS laser mass spectrometry. The outcome is that MCBz is the best suited surrogate for (indirect) on-line measuring of the I-TEQ value in the flue gas by REMPI-TOFMS. The correlation coefficient r of the MCBz concentration to the I-TEQ in the flue gas was 0.85.