Female bushcrickets mated with parasitized males show rapid remating and reduced fecundity (Orthoptera: Phaneropteridae: Poecilimon mariannae)

 Following mating, female bushcrickets undergo a refractory period during which they are sexually unreceptive. The length of the refractory period correlates with the size of the spermatophylax. However, the size of the nuptial gift of acoustically signalling bushcrickets is often reduced as a result of infections by parasitoid flies. We examined the effect of male parasitoid infection on the induction of the refractory period and fecundity of females. We found a drastically reduced refractory period in females if the first mating partner was infected. During this shortened period fewer eggs were deposited, as an effect of the shorter refractory period, whereas the daily egg-laying rate remained the same regardless of whether the females were mated with a parasitized or an unparasitized male. Received: 17 July 2000 / Accepted in revised form: 4 August 2000     

Degradation of silicone polymer in a field soil under natural conditions

Silicone polymers (PDMS = polydimethylsiloxane) are used in numerous consumer and industrial products. Our previous work showed that they will degrade in soil under laboratory conditions. This paper investigates PDMS degradation in the field. Four soil plots (each 2.44 m x 2.44 m) in Michigan were sprayed in May, 1997, with aqueous emulsion to achieve nominal soil PDMS concentrations of 0 (control), 215 (low), 430 (medium), and 860 (high) microg/g. Over the following summer, soil cores (0-5 and 5-10 cm) were collected every two weeks and analyzed for decrease in-total soil PDMS, and decrease in molecular weight of remaining PDMS. PDMS concentrations decreased 50% in 4.5, 5.3, and 9.6 weeks for the low, medium, and high treatments, respectively. Degradation rates were 0.26 (low), 0.44 (medium), and 0.44 (high) g PDMS/m2 day, indicating that degradation capacity of the soil was exceeded by the High treatment. Dimethylsilanediol (DMSD), the main degradation product, was detected in most samples at <5% of original PDMS. This is consistent with laboratory data showing biodegradation and volatilization of DMSD. Deeper sampling (to 20 cm) found only trace amounts of DMSD, and minor downward movement of the polymer. Respraying and subsequent analysis of one plot with a medium treatment in late August showed slow PDMS degradation during the cool, wet fall, followed by a 40% decrease over winter and extensive degradation during the summer of 1998. The study thus shows that PDMS will degrade under field conditions as predicted from laboratory experiments.     

The Potential of Current- and Wind-Driven Transport for Environmental Management of the Baltic Sea

The ever increasing impact of the marine industry and transport on vulnerable sea areas puts the marine environment under exceptional pressure and calls for inspired methods for mitigating the impact of the related risks. We describe a method for preventive reduction of remote environmental risks caused by the shipping and maritime industry that are transported by surface currents and wind impact to the coasts. This method is based on characterizing systematically the damaging potential of the offshore areas in terms of potential transport to vulnerable regions of an oil spill or other pollution that has occurred in a particular area. The resulting maps of probabilities of pollution to be transported to the nearshore and the time it takes for the pollution to reach the nearshore are used to design environmentally optimized fairways for the Gulf of Finland, Baltic Proper, and south-western Baltic Sea.     

Magma Mixing in Bolivian Tin Porphyries

   Received: 16 April 1998 / Accepted in revised form: 27 August 1998     

Prenatal diagnosis of partial agenesis of the corpus callosum in a fetus with thanatophoric dysplasia type 2

A fetus with thanatophoric dysplasia type 2 (TD2) associated with cloverleaf skull and abnormal development of the corpus callosum is reported. This case represents the first prenatal direct visualization of a partial agenesis of the corpus callosum (ACC) using high-resolution ultrasonography and colour power Doppler, which was confirmed by post-mortem magnetic resonance imaging (MRI). The causal link between cloverleaf skull in TD and partial ACC is discussed. Copyright © 2002 John Wiley & Sons, Ltd.     

Comparison of precipitation chemistry measurements obtained by the Canadian Air and Precipitation Monitoring Network and National Atmospheric Deposition Program for the period 1995–2004

Precipitation chemistry and depth measurements obtained by the Canadian Air and Precipitation Monitoring Network (CAPMoN) and the US National Atmospheric Deposition Program/National Trends Network (NADP/NTN) were compared for the 10-year period 1995–2004. Colocated sets of CAPMoN and NADP instrumentation, consisting of precipitation collectors and rain gages, were operated simultaneously per standard protocols for each network at Sutton, Ontario and Frelighsburg, Ontario, Canada and at State College, PA, USA. CAPMoN samples were collected daily, and NADP samples were collected weekly, and samples were analyzed exclusively by each network’s laboratory for pH, H^?+?, Ca^2?+?, Mg^2?+?, Na^?+?, K^?+?, $\text{NH}_{4}^{+}$ , Cl^???, $\text{NO}_{3}^{-}$ , and $\text{SO}_{4}^{2-}$ . Weekly and annual precipitation-weighted mean concentrations for each network were compared. This study is a follow-up to an earlier internetwork comparison for the period 1986–1993, published by Alain Sirois, Robert Vet, and Dennis Lamb in 2000. Median weekly internetwork differences for 1995–2004 data were the same to slightly lower than for data for the previous study period (1986–1993) for all analytes except $\text{NO}_{3}^{-}$ , $\text{SO}_{4}^{2-}$ , and sample depth. A 1994 NADP sampling protocol change and a 1998 change in the types of filters used to process NADP samples reversed the previously identified negative bias in NADP data for hydrogen-ion and sodium concentrations. Statistically significant biases (α = 0.10) for sodium and hydrogen-ion concentrations observed in the 1986–1993 data were not significant for 1995–2004. Weekly CAPMoN measurements generally are higher than weekly NADP measurements due to differences in sample filtration and field instrumentation, not sample evaporation, contamination, or analytical laboratory differences.