Prenatal diagnosis of an intra-abdominal sacrococcygeal teratoma

The prenatal diagnosis of a presacral (type IV) sacrococcygeal teratoma (SCT) is described. The initial ultrasound appearance was suggestive of a lower urinary tract obstruction, but further ultrasonic examination and radiological imaging using contrast medium led to the diagnosis of SCT. This is the first prenatal diagnosis of a totally intra-abdominal SCT.     

Heterotrophic community-level physiological profiles of domestic wastewater following treatment by small constructed subsurface flow wetlands.

Seasonal treatment performance of small-surface flow wetlands was evaluated during their second operational year and compared with community-level physiological profiles (CLPP) of the heterotrophic bacterial community obtained from sole-carbon source utilization patterns in BIOLOG GN (Haywood, California) microplates. The CLPP patterns varied significantly by season, indicating reduced functional diversity in the heterotrophic community during warmer months of active plant growth (April through October). Principal component analysis (PCA) suggested that the functional community differed in planted versus unplanted wetlands during the growing season. Wetlands generally improved wastewater quality; however, treatment performance was reduced in the second year. Despite differences in the heterotrophic community suggested by CLPP, treatment efficiency with respect to removal of five-day biochemical oxygen demand or reduction in fecal indicator organisms generally was not significantly changed as a function of growing season or plant treatment.     

Noble metal catalysts for methane removal

Using a bench-scale rig, the activities of Pt, Pd and Pt+Pd catalysts supported on gamma-Al(2)O(3) and on TiO(2) (anatase) for the complete oxidation of methane (300 ppmv) in air have been measured as a function of temperature; values of T(10), T(50) and T(90) together with the Arrhenius parameters (activation energy and pre-exponential factor) are reported. Pt is less active than Pd when deposited on the surface of the TiO(2), but more active when deposited on gamma-Al(2)O(3), however when combined, the Pt+Pd mixture is more active than either metal individually. The T(10) for Pt+Pd/gamma-Al(2)O(3) was being as low as 228 degrees C. The significance of the Arrhenius parameters, for metal containing catalysts is that they exhibit compensation with increasing activation energy, while securing a more rapid increase in conversion from 0% to 100% when the temperature is increased.     

Native plant species suitable as bioindicators and biomonitors for airborne fluoride

For 30-40 years airborne fluoride, usually in the form of HF or SiF4, was one of the most important and damaging air pollutants affecting forests, crops and natural vegetation. It is much more toxic than most other air pollutants such as O3 or SO2 because injury to the most sensitive species begins when they are exposed to a concentration below 1 ppb (ca. 0.8 microg m(-3)) for a 1- to 3-day period. The long-term threshold concentration is around 0.25-0.30 microg m(-3). Higher concentrations and longer durations of exposure induce much more rapid and extensive injury. However, there is a difference in sensitivity between the most and least sensitive species of around 2-3 orders of magnitude and most species possess a degree of resistance. Dramatic improvements in engineering technology have greatly reduced emissions but because of the high toxicity, cases of vegetation injury are still common, even in developed countries, and cases involving litigation still occur. Therefore there is a continuing need for bioindicators and biomonitoring of fluorides, so this paper reviews the subject, drawing attention to the strengths and limitations of the techniques. Visible symptoms are described and illustrated and tables of relative sensitivity are given and their limitations discussed. Finally, examples of biomonitoring in Europe and the USA are presented.     

Concentration field and turbulent fluxes during the mixing of two buoyant plumes

In this work an experimental study of mixing of two identical plumes, carried out in a turbulent neutral boundary layer generated in a wind tunnel, is presented. Measurements have been performed with fast flame ionisation detectors (FFIDs) and a two-component Laser-Doppler Anemometer system. Results allow the study of both the average and the fluctuating concentration field, including the turbulent vertical and longitudinal mass fluxes, in single plumes and during the interaction of two identical plumes. This information gives insight into the details of the mixing phase of the two plumes. Results of trajectories and additional rise (due to plume interactions) have been compared with previous measurements carried out in laminar cross-flows, showing similar behaviour. Concentration distributions in plume cross-sections in turbulent cross-flows differ from those measured in laminar cross-flows. Average vertical and longitudinal velocity measurements into the plume core show the strength of the shielding effect of the upwind plume and some details of interaction between the counter-rotating vortex pairs (CVPs). For large values of the alignment angle φ, between the line joining the stacks and the cross-flow, an average negative vertical velocity is measured in the middle of the plume even if its centre of mass is rising. This downward velocity is induced by the slow interaction of the CVPs and generates a vertical stretching of the plume and negative rise enhancement. Vertical turbulent fluxes change sign on the plume centreline and are of opposite sign with respect to the longitudinal turbulent fluxes. Results indicate a good linearity between vertical turbulent fluxes and concentration gradients, with different proportionality for the top and bottom parts of the plume (especially in the near field) indicating that dispersion could be described by a gradient-transfer model.     

Diel cycles of activity,metabolism, and ammonium concentration in tropical holothurians

Movement rate, oxygen consumption, and respiratory tree ammonium concentration were measured in situ in the holothurians Pearsonothuria graeffei and Holothuria edulis in the Agan-an Marine Reserve, Sibulan, Philippines (9°20′30″N, 123°18′31″E). Measurements were made both day and night for both species during April–July 2005. P. graeffei had significantly higher movement rate during the day than at night (1.14 and 0.27 m h⁻¹, respectively; three-way ANOVA, P < 0.05) while H. edulis had higher movement rate at night compared to the day (0.83 and 0.07 m h⁻¹, respectively), spending the daylight hours sheltering under coral. More than 80% of H. edulis had movement rate of zero during the day. Oxygen consumption of P. graeffei was significantly higher during the day than at night (1.61 and 0.83 μmol O₂ g⁻¹ h⁻¹, respectively; two-way ANCOVA, P < 0.05), but the reduction at night was not as pronounced as the reduction in movement. H. edulis had a 75% reduction in oxygen consumption during the day compared to night (0.51 and 1.96 μmol O₂ g⁻¹ h⁻¹, respectively), matching this species’ reduced movement rates during the day. Ammonium concentration in water withdrawn from the respiratory trees of P. graeffei during the day (12.0 μM) was three times higher than in respiratory tree water sampled at night (4.3 μM) and 15 times higher than ambient seawater (0.8 μM; three-way ANOVA, P < 0.05). Ammonium concentration in the respiratory tree water of H. edulis was six times higher at night (14.6 μM) than during the day (2.2 μM) and 16 times higher than that of ambient seawater (0.9 μM). Even though H. edulis and P. graeffei are found within the same coral reef environment, they may affect different substrates and reef organisms due to their different habitats and distinct but opposite diel cycles.     

An assessment of variation in molluscan grazing pressure on Hong Kong rocky shores

Several methods of assessment have been used to document variation in grazing pressure on temperate rocky shores, although often these methods are applied without consideration of local conditions or species. In this study, a comparison was made between abundance counts of inactive molluscan grazers at low tide, direct observations of grazer activity and distribution throughout day and night tidal cycles, and records of grazing marks on wax discs, for the mid-shore of Hong Kong. The abundance of grazers found during low-tide counts varied among dates, sites and species. This method, however, did not record all grazer species that day/night observations showed to migrate from the low shore with the rising tide. Low-tide counts, therefore, underestimate grazing pressure (number of active grazers per unit area) and grazer guild (number of species). Grazing marks on wax discs also recorded a greater number of species than the low-tide counts of inactive grazers, and included grazers that were seen to migrate up shore during day/night observations. Certain limpet species, however, avoided the wax and did not leave grazing marks, showing this method to also underestimate grazing pressure. All methods showed grazing pressure to be variable at spatial scales of tens of metres or less and also temporally variable between sampling dates. The sole use of either low-tide counts or wax discs is likely to underestimate grazing pressure, due to variation in shore topography and grazer foraging behaviour, especially on shores with a narrow tidal range such as in Hong Kong. To gain a more accurate assessment of total grazing pressure, it is suggested that recording of grazing marks on wax discs should be used in conjunction with direct day/night observations.     

Weapon size versus body size as a predictor of winning in fights between shore crabs, Carcinus maenas (L.)

Relative body size (carapace width) and weapon size (chela length) were used as indicators of resource holding potential (RHP) in the agonistic behaviour of male shore crabs, Carcinus maenas (L.). Weapon size was found to be a more reliable predictor of the outcome of pairwise fights than body size. Crabs with longer chelae than their opponents were more likely to win fights than crabs with relatively larger bodies. Body size had less influence on the outcome of fights. Relative body and weapon size did not influence initiation of contests but did affect the likelihood of winning; however, this was significant only for weapon size. Winning crabs had heavier claws with greater surface area than losing crabs. There was no relationship between relative size and fight duration. The frequency of cheliped display increased with chela length and win- ners performed significantly more displays than losers. Received: 5 February 1997 / Accepted after revision: 20 May 1997     

On marketable air-pollution permits: The case for a system of pollution offsets

After examining the properties of several alternative forms of marketable permit systems for the control of air pollution, this paper proposes a system of pollution offsets as the most promising approach. Under the pollution-offset scheme, sources of emissions are free to trade emissions permits subject to the constraint of no violations of the predetermined air-quality standard at any receptor point. The paper shows that the pollution-offset system has the capacity to achieve the predetermined standards of air quality at the minimum aggregate abatement cost, while making comparatively modest demands both on the sources and on the administering agency.     

Echolocation,development, and vocal communication in the lesser bulldog bat,Noctilio albiventris

Summary Foraging and echolocation behavior and its ontogeny in the lesser bulldog bat, Noctilio albiventris, were studied in Panama under field and captive conditions. The vocalizations utilized for echolocation and communication were monitored. Adult N. albiventris captured insect prey from the water surface employing various combinations of CF/FM (constant frequency and frequency modulated) signals. The proportions of CF/FM and the repetition rate were a function of the bat's activity. Most adults exhibited post-sunset and pre-dawn foraging activity, although several telemetered lactating females foraged for only the half hour after dusk, spending the rest of the night with their babies in the roost. When the juveniles began to leave the roost at the age of two months, they appeared to accompany their mothers on initial flights.Captive infant Noctilio developed slowly, and did not fly until about 5–6 weeks postnatally. They continued to nurse for almost 3 months, even though they were capable of eating solid food at about 6 weeks. Previous to weaning, mothers fed their infants with masticated food from their cheekpouches.At birth, Noctilio emit a combination of long FM isolation calls and shorter CF/FM pulses. Mothers nurse only their own babies which they appear to recognize by a vocal signature contained in the infants' isolation calls. The individual isolation calls, as well as the mother's communication sounds, appear to be variations of an FM sinusoidal wave. The periodicity and amplitude change, and different portions including harmonics are added or deleted. The short CF/FM signals of the infant evolve into the adult orientation type signals as the CF component increases in frequency and the repetition rate increases. These sounds appear to serve a dual function in communication and echolocation. Mother-young pairs were observed to call antiphonally, utilizing CF/short FM signals in retrieval situations. This duetting was also observed in bats flying over the Chagras River after the time the juveniles began to fly, and may function to maintain vocal contact during initial foraging flights.Deceased