Physiologische Anpassungen eines marinen insekts. II. Die Eigenschaften von schwimmenden und absinkenden Eigelegen

The gelatinous egg-masses of Clunio marinus (Diptera; Chironomidae) consist of a tube of jelly containing up to 175 eggs. The swimming egg-mass of the Atlantic populations (Race A) and the sinking egg-mass of the Baltic populations (Race B) have a higher density than the sea water, on which the female spawns; salinity is not important to the swimming or sinking of the egg-masses. Density and sinking velocity of gelatinous egg-masses from Atlantic midges are significantly higher than those from Baltic midges if the eggs are laid on water of the same salinity. The density of the eggs and the quantitative relation of eggs to jelly are the same in both races. The jelly of the egg-masses from the Baltic Sea race swells more than that from the Atlantic Sea race (increase of volume by absorption of water = 3-fold and 2.4-fold, respectively). During swelling the jelly alters from a trough-like shape into a tube-like from which closes around the eggs. If the surface tension of the spawning medium is lowered by use of detergents, the A-spawn will sink. A- and B-spawns occupy different positions at an oil-water interface. Interference contrast microscopy revealed that the A-jelly forms a well-defined outer line in relationship to the surrounding aqueous medium; this line is missing in the B-jelly. The morphological fine surface structures, as seen by the scanning electron microscope, do not explain the different properties of the A- and B-spawn. Extracts and hydrolysates of jelly material were separated by thin-layer chromatography. The results indicate that the spawn jelly of C. marinus consists of a polysaccharide-protein-complex, similar to the jellies of other invertebrates. It is rather probable that the chemical structure or the components of the jellies from A- and B-populations are not exactly the same; this would explain the different properties described. The ecological significance of swimming and sinking gelatinous egg-masses and the taxonomical position of both midge populations are discussed.     

Vertical distribution of radionuclides in soil of a grassland site in Chernobyl exclusion zone

Five soil profiles from a site about 8 km SE of the Chernobyl NPP were investigated for the vertical distribution of radionuclides. The average (137)Cs-inventory at the site is about 2.6 MBq/m(2) (reference date 1 May 1986). Apart from (137)Cs, the following radionuclides have been identified (their activity ratios to (137)Cs in brackets): (134)Cs (0.537), (125)Sb (0.068), (60)Co (0.0022), (154)Eu (0.016), (155)Eu (0.020), (94g)Nb (9.5E-5), (239/240)Pu (0.0088), (238)Pu (0.040), (90)Sr (0.30) and (241)Am (0.011). Apparent vertical migration velocities are between 0.14 and 0.26 cm/a, apparent dispersion coefficients range from 0.02 to 0.13 cm(2)/a. The rankings of the velocities v for different radionuclides are (Sr, Cs, Sb, Co, Pu)< Am < Eu and Sr < (Cs, Nb), for D, the following rankings have been found: (Nb, Sr, Cs) < Am < Eu, Cs相似文献   

Dietary antioxidants, lipid peroxidation and plumage colouration in nestling blue tits Cyanistes caeruleus

Carotenoid pigments are responsible for many of the red, yellow and orange plumage and integument traits seen in birds. One idea suggests that since carotenoids can act as antioxidants, carotenoid-mediated colouration may reveal an individual's ability to resist oxidative damage. In fact, there is currently very little information on the effects of most dietary-acquired antioxidants on oxidative stress in wild birds. Here, we assessed the impacts on oxidative damage, plasma antioxidants, growth and plumage colouration after supplementing nestling blue tits Cyanistes caeruleus with one of three diets; control, carotenoid treatment or α-tocopherol treatment. Oxidative damage was assessed by HPLC analysis of plasma levels of malondialdehyde (MDA), a by-product of lipid peroxidation. Contrary to predictions, we found no differences in oxidative damage, plumage colouration or growth rate between treatment groups. Although plasma lutein concentrations were significantly raised in carotenoid-fed chicks, α-tocopherol treatment had no effect on concentrations of plasma α-tocopherol compared with controls. Interestingly, we found that faster growing chicks had higher levels of oxidative damage than slower growing birds, independent of treatment, body mass and condition at fledging. Moreover, the chromatic signal of the chest plumage of birds was positively correlated with levels of MDA but not plasma antioxidant concentrations: more colourful nestlings had higher oxidative damage than less colourful individuals. Thus, increased carotenoid-mediated plumage does not reveal resistance to oxidative damage for nestling blue tits, but may indicate costs paid, in terms of oxidative damage. Our results indicate that the trade-offs between competing physiological systems for dietary antioxidants are likely to be complex in rapidly developing birds. Moreover, interpreting the biological relevance of different biomarkers of antioxidant status represents a challenge for evolutionary ecology.     

A previously unrecognized group of Middle Jurassic triconodontan mammals from Central Asia

Ferganodon narynensis gen. et sp. nov. is represented by a lower molariform tooth from the Middle Jurassic (Callovian) Balabansai Svita in Kyrgyzstan. The new genus is allied with Klamelia zhaopengi Chow and Rich 1984 from the Middle Jurassic Shishugou Formation in Xinjiang, northwest China to the new family Klameliidae based on parallelogram-shaped lower molariforms, imbricating rather than interlocking of cusps e-d-f, by a peculiar distolabial cingulid cusp, and by vertical folding of the enamel on the labial crown side. The new family Klameliidae fam. nov. is most similar to Gobiconodontidae by the structure of the molariform teeth and represents a previously unrecognized radiation of eutriconodontan mammals possibly endemic to Central Asia.     

Reduction of NO by CO using Pd-CeTb and Pd-CeZr catalysts supported on SiO2 and La2O3-Al2O3

The catalytic activity of Pd catalysts supported on Ce_0.73Tb_0.27O_x/SiO₂, Ce_0.6Zr_0.4O_x/SiO₂, Ce_0.73Tb_0.27O_x/La₂O₃-Al₂O₃ and Ce_0.6Zr_0.4O_x/La₂O₃-Al₂O₃ was studied using the reduction of NO by CO. The catalysts were characterized by X-ray fluorescence, surface area, X-ray diffraction, temperature-programmed reduction, CO chemisorption and oxygen storage capacity. Temperature-programmed reduction results indicated that Tb or Zr incorporation improves the reducibility and oxygen storage capacity. CO chemisorption data suggested the presence of large PdO particles due to the low CO/Pd ratio. No significant differences were obtained in light off temperatures (T_{Light off}) for all Pd catalysts and the most active was 1.5%Pd/Ce_0.6Zr_0.4O_x/SiO₂.     

Effects of different management strategies on long-term trends of Australian threatened and near-threatened mammals

Monitoring is critical to assess management effectiveness, but broadscale systematic assessments of monitoring to evaluate and improve recovery efforts are lacking. We compiled 1808 time series from 71 threatened and near-threatened terrestrial and volant mammal species and subspecies in Australia (48% of all threatened mammal taxa) to compare relative trends of populations subject to different management strategies. We adapted the Living Planet Index to develop the Threatened Species Index for Australian Mammals and track aggregate trends for all sampled threatened mammal populations and for small (<35 g), medium (35–5500 g), and large mammals (>5500 g) from 2000 to 2017. Unmanaged populations (42 taxa) declined by 63% on average; unmanaged small mammals exhibited the greatest declines (96%). Populations of 17 taxa in havens (islands and fenced areas that excluded or eliminated introduced red foxes [Vulpes vulpes] and domestic cats [Felis catus]) increased by 680%. Outside havens, populations undergoing sustained predator baiting initially declined by 75% but subsequently increased to 47% of their abundance in 2000. At sites where predators were not excluded or baited but other actions (e.g., fire management, introduced herbivore control) occurred, populations of small and medium mammals declined faster, but large mammals declined more slowly, than unmanaged populations. Only 13% of taxa had data for both unmanaged and managed populations; index comparisons for this subset showed that taxa with populations increasing inside havens declined outside havens but taxa with populations subject to predator baiting outside havens declined more slowly than populations with no management and then increased, whereas unmanaged populations continued to decline. More comprehensive and improved monitoring (particularly encompassing poorly represented management actions and taxonomic groups like bats and small mammals) is required to understand whether and where management has worked. Improved implementation of management for threats other than predation is critical to recover Australia's threatened mammals.     

Evaluating the influence of nature connection and values on conservation attitudes at a tropical deforestation frontier

Inner phenomena, such as personal motivations for pursuing sustainability, may be critical levers for improving conservation outcomes. Most conservation research and policies, however, focus on external phenomena (e.g., ecological change or economic processes). We explored the factors shaping 9 conservation attitudes toward forest and wildlife protection among colonist farmers around an Amazonian deforestation frontier. Our data comprised 241 face-to-face quantitative surveys, complemented with qualitative insights from open-ended questionnaire responses and opportunistic semistructured interviews. To account for the full spectrum of possible inner motivations, we employed measures of nature connection (indicating biospheric motivation) and personal values organized around the traditionalism (traditionalist through to high openness to change) and universalism dimensions (egoistic through to altruistic motivations). We used averaged beta-binomial generalized linear models to assess the role of external factors (socioeconomic, sociodemographic, and environmental) and personal (inner) motivations on the variation in attitudes. Each attitude was modeled separately. The relative importance of each predictor was judged by the proportion of models where it appeared as significant. Proconservation views were expressed by the majority (at least 65%) of the respondents in 7 out of the 9 attitude models. The most consistent predictors were emotional nature connection and personal values (significant in 4–6 out of 9 models), rather than external phenomena (significant in 0–5 models). However, the poorest farmers had lower scores on the agreement with prioritizing nature over development (𝛽 = –0.52, 95% CI: –0.96 to –0.07). Qualitative data also indicated that economic barriers hinder forest conservation on farms. These results suggest that biospheric, traditionalistic, and altruistic motivations promote people's proconservation attitudes, but nurturing these latent motivations is unlikely to improve conservation outcomes if material poverty remains unaddressed. Integrating the inner–outer perspective into conservation thinking and practical interventions could foster environmental stewardship and increase human well-being.     

The role of regulatory fit in visionary leadership

It is generally argued that leader visions motivate followers by focusing on reaching desirable end‐states. However, it has also been suggested that visions may motivate followers by focusing on avoiding undesirable situations. In this paper we investigate the effects of appeals that focus on preventing an undesirable situation (i.e., prevention‐appeals) as well as appeals that focus on promoting a desirable situation (i.e., promotion‐appeals). We argue that the effectiveness of promotion‐ and prevention‐appeals is contingent on follower regulatory focus. In two experiments we show that prevention‐appeals lead to better performance than promotion‐appeals for more prevention‐focused followers, while the reverse is true for more promotion‐focused followers. We find this pattern for a dispositional measure of follower regulatory focus (Study 1) as well as for a manipulation of follower regulatory focus (Study 2). Copyright © 2009 John Wiley & Sons, Ltd.