Factors predicting male fertilization success in an external fertilizer

In postcopulatory sexual selection both sperm competition and cryptic female choice are considered to be important selective agents, but their relative importance for male fertilization success has received little attention. We tested whether sperm quality, male spawning coloration, male heterozygosity, and genetic overlap with the female explained a male’s fertilization success in controlled in vitro fertilization competition trials between equal numbers of sperm from pairs of male Arctic charr (Salvelinus alpinus), an external fertilizer. Offspring were genotyped to determine each males’ share of paternity. The velocity of a male’s sperm relative to the velocity of the competing male’s sperm was the best predictor of male fertilization success. Yet, sperm velocity was not related to spawning coloration or male heterozygosity. In fact, the most brightly colored male in a pair had the lowest fertilization probability. This could result from cryptic female choice for pale males, but might rather be a result of paler males producing more competitive sperm than more colored males. Furthermore, the more microsatellite alleles a male shared with the female relative to the competing male, the higher fertilization success he had. We argue that this latter may be an effect of assortative cryptic female choice, which might prevent hybridization with sympatric Arctic charr morphs or one form of kin selection.     

Sex ratio in lesser black-backed gull in relation to environmental pollutants

In birds, there is ample evidence that the mother can manipulate the sex of the young and produce more of the sex, which gives the highest fitness return. This has previously been documented in gulls, Laridae. Gulls are sexually size dimorphic with males larger than females, and there is good evidence that parents in poor body condition switch their investment to the smallest sex. In the present study, we examined the primary sex ratio and the survival of male and female chicks of lesser black-backed gull (Larus fuscus fuscus) in relation to their blood levels of organochlorines (OCs), perfluorinated compounds (PFCs) and polybrominated diphenyl ethers (BDE-47). We show that females with high levels of OCs (but not PFCs and BDE-47) are likely to skew their sex ratio at hatching towards female offspring. Few females had very high levels of OCs, and the many females with low levels of OCs overproduced sons resulting in a male skew at hatching (59%). The survival of female offspring was lower than the survival of male offspring, causing an even stronger male skew in sex ratio (71%). There is evidence to conclude that circulating levels of OCs in the blood of females may have detrimental effect on the sex allocation strategy and could be of serious threat to the population. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users.     

Speciation of Cd and Zn in contaminated soils assessed by DGT-DIFS, and WHAM/Model VI in relation to uptake by spinach and ryegrass

A pot experiment was carried out to investigate the impact of Cd and Zn extractability in soil and speciation in pore water of industrial contaminated soils, on metal concentration in a metal sensitive species like spinach (Spinacia oleracea) and a more metal tolerant species like Italian ryegrass (Lolium multiflorum). For chemical speciation of Cd and Zn in pore water, WHAM/Model VI version 6.0 was used. The DGT technique was used to determine the effective concentration, C(E), of Cd and Zn in soils. The free ion activity in pore water correlated well with the contents in plants, and there was a linear relationship between the C(E) values and the concentration of Cd and Zn in both spinach and ryegrass in the non-toxic range. However, the C(E) values usually overestimated the plant contents when plants, particularly the spinach plants, were subjected to toxic concentration in the pore water. Metal uptake decreased in plants affected by toxicity, whereas metal binding to the Chelex resin did not. Thus, we found no linear relationship between the C(E) and metal contents in spinach, whereas a linear relationship was found between C(E)-Zn and the Zn concentration in ryegrass (r2=0.96, p<0.001). For Cd in ryegrass this relationship was weak (r2=0.53, p=0.18). This study indicates that the transport of metals from labile metal pools to the DGT-resin is linearly related to plant uptake only when plants are growing well, and that the applicability of DGT as an indicator for plant uptake seems species dependent.     

Speed choice versus celeration behavior as traffic accident predictor

INTRODUCTION: The driver celeration behavior theory predicts that this variable is superior to all other variables as a predictor of individual traffic accident involvement, including the ever-important speed parameter. The study was undertaken to test this prediction. Also, it was expected that most variables would associate fairly strongly. METHOD: The use of speed choice as a predictor of individual traffic accident record was discussed, and four different variants of this variable (maximum, net mean, gross mean, and standard deviation of speed) identified. These variables were then compared to celeration behavior as predictors of accident record of bus drivers in the same set of data. RESULTS: Celeration behavior was found to be slightly superior, in accordance with the prediction made from the driver celeration behavior theory, although the differences were not significant. Furthermore, the predictor variables were found to associate fairly strongly between themselves, with the exception of gross mean speed, and to have fair stability over time, especially when aggregated. CONCLUSIONS: These results tentatively confirm some of the predictions made from the driver celeration behavior theory. As the results for accidents were in the expected direction, but not significant, and the maximum speed variable may have suffered from a ceiling effect, the conclusion is provisional. Impact on industry: The correlations found were strong enough to warrant the use of celeration behavior as a predictive variable for transportation companies in their safety work.     

An environmental tax-shift with indirect desirable effects

Imposing environmental taxation on external costs of energy will not only affect the environmental impact of the energy sector itself, but it will tend to decrease environmental damage from other sectors of the economy as well. We have assessed the effects of a shift of taxation from taxing labour to taxation of external costs caused in the energy sector. Several examples give results compatible with the hypothesis that the changing price relation between labour and energy resulting from such a tax shift will make re-use, repairs and recycling increasingly competitive and thus tend to decrease mining as well as waste production. Likewise, less energy-intensive commodities and services in general would become increasingly competitive, and would tend to decrease the environmental load further. These environmentally desirable effects are beyond the taxed external effects of the energy sector itself and occur as an indirect effect of the increased relative price of energy.     

"The Driver Behaviour Questionnaire as a predictor of accidents: A meta-analysis" Comments

A previously published meta-analysis of the predictive power of the Manchester Driver Behaviour Questionnaire (DBQ) versus road traffic crashes is criticized upon a number of counts, including the incomplete handling of common method variance, failure to control for exposure and how the correction for unreliability of the accident variable was undertaken. It is concluded that the results reported, and the conclusions drawn from these, are too favorable to the DBQ, despite the effect sizes being

Common method variance

The main problem associated with the interpretation of the DBQ/accidents association is common method variance (i.e., systematic biases in the self-reports used), which create part or all of the associations found (Chang et al., 2010, Podsakoff et al., 2003). Common method variance may be due to a number of different factors, and in some studies, substantial effects have been found (e.g., Hessing, Elffers, &; Weigel, 1988; for reviews see Cote and Buckley, 1987, Podsakoff et al., 2003). This

Conclusions

To summarize, we believe that the meta-analysis of de Winter and Dodou is somewhat too favorable to the DBQ by failing to make the above points. Yet we paradoxically agree with de Winter and Dodou in one of their conclusions and recommendations; more studies using other-source criteria are needed. The self-report-source only data are not reliable, and conclusions about the predictive power of the DBQ factors versus traffic safety are not yet possible to draw.

     

Influence of diet and sea ice drift on organochlorine bioaccumulation in Arctic ice-associated amphipods

The drifting sea ice has been suggested as important in the transport and concentration of organic matter and pollutants in the Arctic. We collected sea ice-associated amphipods in the marginal ice zone north of Svalbard and in the Fram Strait in September 1998 and 1999 to assess contaminant accumulation in ice-associated organisms. Organochlorine concentrations increased from the more herbivorous Apherusa glacialis to the more carnivorous Gammarus wilkitzkii and the more necrophagous Onisimus spp. The relative contribution of compound classes to the sum of organochlorines differed between the amphipod families, with a higher relative contribution of hexachlorocyclohexanes (HCHs) in A. glacialis. The composition of the compound classes HCHs. chlordanes and dichlorodiphenyltrichloroethanes (DDTs) was similar between the amphipod families, whereas the profiles of polychlorinated biphenyls (PCBs) differed. The occurrence of organochlorines differed spatially, with higher alpha-HCH concentrations in amphipods from the Fram Strait in comparison with amphipods collected north of Svalbard. This could be related to the sea ice drift route, since sea ice in the Fram Strait had a drift route across the central Arctic Ocean, while the sea ice north of Svalbard had a western drift route to the sampling stations. Even though marine invertebrates have direct uptake by passive diffusion of contaminants across their gills. our results imply that the species' ecology such as diet is important in the bioaccumulation process of organic pollutants. In addition, the results show that sea ice drift route influences the concentrations of organochlorine pollutants in ice-associated organisms.     

Methods of ciliary filter feeding in adult Phoronis muelleri (phylum Phoronida) and in its free-swimming actinotroch larva

Microscope-video recordings were used to describe basic characteristics of particle capture in adult Phoronis muelleri and in its actinotroch larva. The larva captures food particles by means of close interplay between the tentacles and the oral hood. Suspended particles in the incoming water flow set up by the lateral "pump" cilia on the tentacles approach the tentacles with a velocity of about 1.5 mm s^-1. Near the tentacles, the particles are stopped by the stiff sensory laterofrontal cilia acting as a mechanical sieve. Simultaneous with stoppage of a particle, the oral hood is rapidly lifted so that water from the surrounding area flows in to occupy the volume created under the hood. Due to the proximity of the tentacle with the arrested particle, this suction will draw the particle away from the laterofrontal cilia into the increased space under the oral hood with a velocity of about 0.6 mm s^-1 before it is subsequently carried to the mouth. If a particle is stopped near the tip of a tentacle this may trigger a tentacle flick, with a tip velocity of about 5-7 mm s^-1, which brings the particle down toward the lifting edge of the hood. A stopped particle may cause a local disruption of the metachronism of the lateral cilia for about 0.14 s. Likewise in the adult, when an incoming particle with a velocity of about 1.6 mm s^-1 is stopped near the tip of a tentacle this triggers a flick, which brings the particle down towards the mouth. The duration of the active flick phase is about one-tenth of the flick cycle. Only when a particle is stopped on the outer part of a tentacle is a flick triggered. Otherwise the particle is either transported down along the frontal surface of the tentacle by means of the frontal cilia, or transferred into the downward current created by the lophophore. The metachronal wave velocity is about 0.25 mm s^-1, the wavelength about 12 µm, and hence the ciliary beat frequency about 21 Hz (at ~16°C). Essential features of the filter-feeding process in both actinotroch larvae and adult P. muelleri reported here resemble the ciliary-sieving process described for bryozoans in recent years. It should be pointed out that the stiff, mechanosensory laterofrontal cilia may be a decisive factor for understanding ciliary upstream collecting, also in pterobranchs and brachiopods in which sensory laterofrontal cilia are present.     

A general approach to transform a lake model for one radionuclide (radiocesium) to another (radiostrontium) and critical model tests using data for four Ural lakes contaminated by the fallout from the Kyshtym accident in 1957

This paper presents results of a model test carried out within the framework of the COMETES project (EU). The aim of the work was to change the structure of the MOIRA lake model for radiocesium so that it can be applied more generally for, in principle, all types of radionuclides and heavy metals. This general lake model is used within the MOIRA decision support system (DSS; MOIRA and COMETES are acronyms for EU-projects). The model is based on a set of differential equations and a specific modelling structure. It incorporates all important fluxes to, from and within lakes in a general manner. Yet the model is driven by a minimum of variables accessible from standard maps and monitoring programs. The model can be separated into two parts, a general part with equations applicable for all types of water pollutants and a substance-specific part. This model has previously been validated for 137Cs from many lakes covering a wide domain and yielded excellent predictive power. The alterations discussed in this work are meant to be general and radiostrontium is used as a typical element. Radiostrontium is known to be more mobile than radiocesium and all abiotic parts of the model handling fixation and mobility have been altered. The new model for 90Sr has been critically tested using data from four lakes heavily contaminated with 90Sr from the Kyshtym accident in the Southern Urals, Russia, using empirical data from a period from 1958 to 1995 for 90Sr in fish (here goldfish), water and sediments.     

Regional scale evidence for improvements in surface water chemistry 1990-2001

The main aim of the international UNECE monitoring program ICP Waters under the Convention of Long-range Transboundary Air Pollution (CLRTAP) is to assess, on a regional basis, the degree and geographical extent of the impact of atmospheric pollution, in particular acidification, on surface waters. Regional trends are calculated for 12 geographical regions in Europe and North America, comprising 189 surface waters sites. From 1990-2001 sulphate concentrations decreased in all but one of the investigated regions. Nitrate increased in only one region, and decreased in three North American regions. Improvements in alkalinity and pH are widely observed. Results from the ICP Waters programme clearly show widespread improvement in surface water acid-base chemistry, in response to emissions controls programs and decreasing acidic deposition. Limited site-specific biological data suggest that continued improvement in the chemical status of acid-sensitive lakes and streams will lead to biological recovery in the future.