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91.
Kibii JM Churchill SE Schmid P Carlson KJ Reed ND de Ruiter DJ Berger LR 《Science (New York, N.Y.)》2011,333(6048):1407-1411
The fossil record of the hominin pelvis reflects important evolutionary changes in locomotion and parturition. The partial pelves of two individuals of Australopithecus sediba were reconstructed from previously reported finds and new material. These remains share some features with australopiths, such as large biacetabular diameter, small sacral and coxal joints, and long pubic rami. The specimens also share derived features with Homo, including more vertically oriented and sigmoid-shaped iliac blades, greater robusticity of the iliac body, sinusoidal anterior iliac borders, shortened ischia, and more superiorly oriented pubic rami. These derived features appear in a species with a small adult brain size, suggesting that the birthing of larger-brained babies was not driving the evolution of the pelvis at this time. 相似文献
92.
René Gislum Lise C. Deleuran Kristian Kristensen Birte Boelt 《Journal of plant nutrition》2013,36(9):1394-1410
The effect of different autumn and spring nitrogen (N) application rates on plant establishment, plant development, and seed yield were tested in a field experiment using tall fescue (Festuca arundinacea Schreb.). Results clearly showed that the optimum distribution of N between autumn and spring to achieve the highest seed yield and economical benefit was dependent on the choice of cover crops and location. The economically optimum N application rate was in the range from 44 to 73 kg ha?1 in autumn and 94 to 157 kg ha?1 in spring. The results are discussed in relation to Danish N regulations and plant establishment and development. 相似文献
93.
KH Kjær SA Khan NJ Korsgaard J Wahr JL Bamber R Hurkmans M van den Broeke LH Timm KK Kjeldsen AA Bjørk NK Larsen LT Jørgensen A Færch-Jensen E Willerslev 《Science (New York, N.Y.)》2012,337(6094):569-573
Global warming is predicted to have a profound impact on the Greenland Ice Sheet and its contribution to global sea-level rise. Recent mass loss in the northwest of Greenland has been substantial. Using aerial photographs, we produced digital elevation models and extended the time record of recent observed marginal dynamic thinning back to the mid-1980s. We reveal two independent dynamic ice loss events on the northwestern Greenland Ice Sheet margin: from 1985 to 1993 and 2005 to 2010, which were separated by limited mass changes. Our results suggest that the ice mass changes in this sector were primarily caused by short-lived dynamic ice loss events rather than changes in the surface mass balance. This finding challenges predictions about the future response of the Greenland Ice Sheet to increasing global temperatures. 相似文献
94.
The distribution of 35S-labelled sulfadiazine and 14G-labelled trimethoprim was studied in rainbow trout by use of whole body autoradiography and liquid scintillation. As compared to mammals, gastrointestinal absorption and elimination were slow. Accumulation in the skin and the uveal tract of the eye was observed for both drugs tested. The results also indicated that the bile was an important route of excretion. Considerable radioactivity was still present in the skin at 144 hr. survival time. 相似文献
95.
Pigs and chickens were fed diets containing increased concentrations of the single cell protein (SCP), Pruteen, in order to investigate the effects of a diet containing high levels of nucleic acids on the activity of DNase in intestinal contents. Increased levels of SCP in the diet generally resulted in increased DNase activity in intestinal contents.Significant differences at P≦0.05, were found between the control groups and most of the experimental groups in both species.With the exception of the 2 groups given the highest levels of SCP in the chicken experiment, the DNases in the large intestines were not inhibited by antisera produced against DNase in pancreatic juice. 相似文献
96.
Deposition variability from a conventional field sprayer, and effects of wind and travel speed were measured by collecting on small artificial targets in the swath. Whilst deposition on 0.1-m2 plots varied by a factor of 3, deposition on single vertical targets typically varied by a factor of 10 and on horizontal targets by a factor of 6. Distinct transversal deposition patterns appeared according to wind direction. The quantity and structure of variability was compared with wind speed and turbulence intensity, but few significant trends were found. Deposition on vertical targets was enhanced by increasing wind speed or increasing travel speed, whilst effects on horizontal targets were inconsistent. 相似文献
97.
Si Chen Eric van der Graaff Nanna Karkov Ytting Kristian Thorup-Kristensen 《Acta Agriculturae Scandinavica, Section B - Plant Soil Science》2019,69(1):62-74
Selection for deep rooting is critical for the development of genotypes that are able to explore deep soil water and nutrients, particularly as agricultural resources become more limited. However, current root phenotyping techniques demand significant investments of time, money, and effort, and measurements on very young plants or plants grown under soilless culture. This study introduced four novel and simple techniques for fast evaluation of root depth in tube rhizotrons, which enable root observation around the transparent tube walls, and allow roots growing to natural size in semi-field conditions. The first and second innovations involve the introduction of 15N tracer and herbicide to the roots, which estimated root activity by measuring the responses of the shoots aboveground. The third involves placement of a cone deep in the rhizotron, to increase chances to observe more deep roots along the tube walls. The fourth involves measurement of roots that emerge from the rhizotron bottom. The reliability of these techniques were assessed in a series of five experiments during 2014 and 2015. These tests compared two pairs of genotypes that previous studies had shown to have mutually distinctive root traits: the spring wheat pair of ‘April bearded’ vs. ‘Dacke’; and the winter wheat pair of ‘Tabasco’ vs. ‘Genius’, with the first of each pair being the genotype known for deep rooting. Results showed that the new techniques were as good as or better than existing alternatives at accurately measuring root traits. In eight of the nine comparisons, the measurements were consistent with the expectations of root characteristics for these known genotypes. Importantly, the indirect root activity measures (herbicide and 15N) showed the same trend as the direct root observation techniques in all experiments, but higher ability to distinguish the genotypes and more promise for future upscaling for plant breeding. 相似文献
98.
99.
Dana Zimmer Kristian Kiersch Gerald Jandl Ralph Meissner Nikolay Kolomiytsev Peter Leinweber 《Water, air, and soil pollution》2010,211(1-4):299-312
The contamination status of rivers and their floodplains with inorganic and organic pollutants in central Russia is poorly known. We investigated the concentrations of inorganic (As, Cd, Cu, Hg, Ni, Pb and Zn) and persistent organic pollutants (hexachlorocyclohexane, PCBs, cyclodienes, DDX and other pesticides) in floodplain soils of the Oka River catchment (Russia). The level of contamination was generally lower than in the Elbe River floodplain but in the same range as in other European river systems such as floodplains of the rivers Rhine, D?evnice and Yachroma. Only soil samples from the periphery of the city of Ryazan (200 km southeast of Moscow) had a higher anthropogenic enrichment of Cd, Cu and Zn which was comparable to the contaminated Elbe River floodplains. These soils also had the largest concentrations of persistent organic pollutants among all samples from the Oka River catchment. Therefore, the need for large-scale remediation seems to be less urgent than in Central European river catchments and mainly restricted to some “hot spot” areas. 相似文献
100.
GAO Song-juan ZHANG Ren-gang CAO Wei-dong FAN Yuan-yuan GAO Ju-sheng HUANG Jing BAI Jin-shun ZENG Nao-hua CHANG Dan-na Shimizu Katsu-yoshi Kristian Thorup-Kristensen 《农业科学学报》2015,14(12):2512-2520
On the basis of a long-term(30 years) field experiment that involved four rotation systems, rice-rice-winter fallow(RRF), rice-rice-ryegrass(RRG), rice-rice-rape(RRP), and rice-rice-milk vetch(RRV), this study described the effects of green manure on the microbial communities in the red paddy soils using 454 pyrosequencing for the 16 S r RNA gene. The Chao1 richness and non-parametric Shannon's index increased in all soil samples that received green manure treatments. The communities' structures with the green manure applications were significantly dissimilar from that under the winter fallow. Using Metastats tests, many genera in the RRG, RRP and RRV soils were significantly different from those in the RRF soil, including a number of genera that functioned in the nitrogen and sulfur cycles. Analyses of the genera with these functions revealed the shifts in microbial ecosystem functions after long-term green manuring. Changes in the microbial communities increased the ammonium supply and decreased the soil acidification in green-manure-amended soils. Together, these data suggested powerful effects of green manure on both the microbial communities and the biogeochemical cycle driven by the shifts in bacterial functional groups. 相似文献