Most studies of mammal extinctions during the Pleistocene–Holocene transition explore the relative effects of climate change vs human impacts on these extinctions, but the relative importance of the different environmental factors involved remains poorly understood. Moreover, these studies are strongly biased towards megafauna, which may have been more influenced by human hunting than species of small body size. We examined the potential environmental causes of Pleistocene–Holocene mammal extinctions by linking regional environmental characteristics with the regional extinction rates of large and small mammals in 14 Palaearctic regions. We found that regional extinction rates were larger for megafauna, but extinction patterns across regions were similar for both size groups, emphasizing the importance of environmental change as an extinction factor as opposed to hunting. Still, the bias towards megafauna extinctions was larger in southern Europe and smaller in central Eurasia. The loss of suitable habitats, low macroclimatic heterogeneity within regions and an increase in precipitation were identified as the strongest predictors of regional extinction rates. Suitable habitats for many species of the Last Glacial fauna were grassland and desert, but not tundra or forest. The low‐extinction regions identified in central Eurasia are characterized by the continuous presence of grasslands and deserts until the present. In contrast, forest expansion associated with an increase in precipitation and temperature was likely the main factor causing habitat loss in the high‐extinction regions. The shift of grassland into tundra also contributed to the loss of suitable habitats in northern Eurasia. Habitat loss was more strongly related to the extinctions of megafauna than of small mammals. Ungulate species with low tolerance to deep snow were more likely to go regionally extinct. Thus, the increase in precipitation at the Pleistocene–Holocene transition may have also directly contributed to the extinctions by creating deep snow cover which decreases forage availability in winter. 相似文献
The 67th Discussion Forum on Life Cycle Assessment (LCA), organised by partners of the European project RELIEF (RELIability of product Environmental Footprints), focused on methods for better understanding the impacts of land use linked to agricultural value chains. The first session of the forum was dedicated to methods that help in retrospective tracking of land use within complex supply chains. Novel approaches were presented for the integration of increasingly available spatially located land use data into LCA. The second session focused on forward-looking projections of land use change and included emerging, predictive methods for the modelling of land change. The third session considered impact assessment methods related to the use of land and their application together with land change modelling approaches. Discussions throughout the day centred on opportunities and challenges arising from integrating spatially located land use information into Life Cycle Assessment. Increasing amounts of spatially located land use data are becoming available and this could potentially increase the robustness and specificity of Life Cycle Assessment. However, the use of such data can be computationally expensive and requires the development of skills (i.e. use of geographical information systems (GIS) and model coding) within the LCA community. Land change modelling and ecosystem service modelling are associated with considerable uncertainty which must be communicated appropriately to stakeholders and decision-makers when interpreting results from an LCA. The new approaches were found to challenge aspects of the traditional LCA approach—particularly the division between the life cycle inventory and impact assessment and the assumption of linearity between scale and impacts when deriving characterisation factors. The presentations from the DF-67 are available for download (www.lcaforum.ch), and video recordings can be accessed online (http://www.video.ethz.ch/events/lca/2017/autumn/67th.html). 相似文献
Coral Reefs - Adaptation, acclimatization and symbiont diversity are known to regulate thermal tolerance in corals, but the role of these mechanisms remains poorly constrained in other... 相似文献
It has been clearly established that maximal force and power is lower in the morning compared to noon or afternoon hours. This morning neuromuscular deficit can be diminished by regularly training in the morning hours. However, there is limited and contradictory information upon hypertrophic adaptations to time-of-day-specific resistance training. Moreover, no cellular or molecular mechanisms related to muscle hypertrophy adaptation have been studied with this respect. Therefore, the present study examined effects of the time-of-day-specific resistance training on muscle hypertrophy, phosphorylation of selected proteins, hormonal concentrations and neuromuscular performance. Twenty five previously untrained males were randomly divided into a morning group (n = 11, age 23 ± 2 yrs), afternoon group (n = 7, 24 ± 4 yrs) and control group (n = 7, 24 ± 3 yrs). Both the morning and afternoon group underwent hypertrophy-type of resistance training with 22 training sessions over an 11-week period performed between 07:30–08:30 h and 16:00–17:00 h, respectively. Isometric MVC was tested before and immediately after an acute loading exclusively during their training times before and after the training period. Before acute loadings, resting blood samples were drawn and analysed for plasma testosterone and cortisol. At each testing occasion, muscle biopsies from m. vastus lateralis were obtained before and 60 min after the acute loading. Muscle specimens were analysed for muscle fibre cross-sectional areas (CSA) and for phosphorylated p70S6K, rpS6, p38MAPK, Erk1/2, and eEF2. In addition, the right quadriceps femoris was scanned with MRI before and after the training period. The control group underwent the same testing, except for MRI, between 11:00 h and 13:00 h but did not train. Voluntary muscle strength increased significantly in both the morning and afternoon training group by 16.9% and 15.2 %, respectively. Also muscle hypertrophy occurred by 8.8% and 11.9% (MRI, p < 0.001) and at muscle fibre CSA level by 21% and 18% (p < 0.01) in the morning and afternoon group, respectively. No significant changes were found in controls within these parameters. Both pre- and post-training acute loadings induced a significant (p < 0.001) reduction in muscle strength in all groups, not affected by time of day or training. The post-loading phosphorylation of p70S6Thr421/Ser424 increased independent of the time of day in the pre-training condition, whereas it was significantly increased in the morning group only after the training period (p < 0.05). Phosphorylation of rpS6 and p38MAPK increased acutely both before and after training in a time-of-day independent manner (p < 0.05 at all occasions). Phosphorylation of p70S6Thr389, eEF2 and Erk1/2 did not change at any time point. No statistically significant correlations were found between changes in muscle fibre CSA, MRI and cell signalling data. Resting testosterone was not statistically different among groups at any time point. Resting cortisol declined significantly from pre- to post-training in all three groups (p < 0.05). In conclusion, similar levels of muscle strength and hypertrophy could be achieved regardless of time of the day in previously untrained men. However, at the level of skeletal muscle signalling, the extent of adaptation in some parameters may be time of day dependent. 相似文献
Ceramic Li7La3Zr2O12 garnet materials are promising candidates for the electrolytes in solid state batteries due to their high conductivity and structural stability. In this paper, the existence of “polyamorphism” leading to various glass‐type phases for Li‐garnet structure besides the known crystalline ceramic ones is demonstrated. A maximum in Li‐conductivity exists depending on a frozen thermodynamic glass state, as exemplified for thin film processing, for which the local near range order and bonding unit arrangement differ. Through processing temperature change, the crystallization and evolution through various amorphous and biphasic amorphous/crystalline phase states can be followed for constant Li‐total concentration up to fully crystalline nanostructures. These findings reveal that glass‐type thin film Li‐garnet conductors exist for which polyamorphism can be used to tune the Li‐conductivity being potential new solid state electrolyte phases to avoid Li‐dendrite formation (no grain boundaries) for future microbatteries and large‐scale solid state batteries. 相似文献
Soda lakes, with their high salinity and high pH, pose a very challenging environment for life. Microorganisms living in these harsh conditions have had to adapt their physiology and gene inventory. Therefore, we analyzed the complete genome of the haloalkaliphilic photoheterotrophic bacterium Rhodobaca barguzinensis strain alga05. It consists of a 3,899,419 bp circular chromosome with 3624 predicted coding sequences. In contrast to most of Rhodobacterales, this strain lacks any extrachromosomal elements. To identify the genes responsible for adaptation to high pH, we compared the gene inventory in the alga05 genome with genomes of 17 reference strains belonging to order Rhodobacterales. We found that all haloalkaliphilic strains contain the mrpB gene coding for the B subunit of the MRP Na+/H+ antiporter, while this gene is absent in all non-alkaliphilic strains, which indicates its importance for adaptation to high pH. Further analysis showed that alga05 requires organic carbon sources for growth, but it also contains genes encoding the ethylmalonyl-CoA pathway for CO2 fixation. Remarkable is the genetic potential to utilize organophosphorus compounds as a source of phosphorus. In summary, its genetic inventory indicates a large flexibility of the alga05 metabolism, which is advantageous in rapidly changing environmental conditions in soda lakes.
Effects of facial coloration on facial attractiveness judgments are hypothesized to be “universal” (i.e., similar across cultures). Cross-cultural similarity in facial color preferences is a critical piece of evidence for this hypothesis. However, only two studies have directly compared facial color preferences in two cultures. Both of those studies reported that White UK and Black African participants showed similar preferences for facial coloration. By contrast with the cross-cultural similarity reported in those studies, here we show cultural differences in the effects of facial coloration on Chinese and White UK participants' facial attractiveness judgments. While Chinese participants preferred faces with decreased yellowness to faces with increased yellowness, White UK participants preferred faces with increased yellowness to faces with decreased yellowness. Chinese participants also demonstrated weaker preferences for facial redness and stronger preferences for facial lightness than did White UK participants. These results suggest that preferences for facial coloration are not universal. 相似文献