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41.
We combine historical maps and satellite derived data to reconstruct the development of a Swedish boreal landscape over the past 300 years. The aim is to understand legacies from past use patterns in present-day forest composition and consequences for conservation objectives from a landscape perspective. We analyze landscape development in cross-tabulation matrixes, building change trajectories. These trajectories are tested in linear models to explain the distribution of present-day landscape composition of coniferous, mixed, and deciduous forests >110 years. Of 49 tested change trajectories, 11 showed a significant association. Associations for mixed and coniferous forests were similar and linked to characteristics such as forest continuity, which characterized the studied landscape. Deciduous older forests did not show any association to forest continuity but were more likely to occur on areas that specifically shifted from forests with grazing in the 1720s to open impediment (likely indicating low tree coverage) in the 1850s. There were large shifts and spatial redistribution in ownerships over time. Use patterns and legacies varied between small- and large-scale ownership categories as well as within small-scale categories. The legacies found in the study indicate a complex origin of heterogeneous landscape elements such as older deciduous forests. Additionally, the origin of the legacies indicates a potential need to diversify conservation management based on the influence of past use patterns. Despite large inconsistencies in historical and contemporary data we argue that this type of analysis could be used to further understand the distribution of landscape elements important for conservation objectives. 相似文献
42.
Jussi T. ERONEN P. David POLLY Marianne FRED John DAMUTH David C. FRANK Volker MOSBRUGGER Christoph SCHEIDEGGER Nils Chr. STENSETH Mikael FORTELIUS 《Integrative zoology》2010,5(2):88-101
We outline here an approach for understanding the biology of climate change, one that integrates data at multiple spatial and temporal scales. Taxon-free trait analysis, or “ecometrics,” is based on the idea that the distribution in a community of ecomorphological traits such as tooth structure, limb proportions, body mass, leaf shape, incubation temperature, claw shape, any aspect of anatomy or physiology can be measured across some subset of the organisms in a community. Regardless of temporal or spatial scale, traits are the means by which organisms interact with their environment, biotic and abiotic. Ecometrics measures these interactions by focusing on traits which are easily measurable, whose structure is closely related to their function, and whose function interacts directly with local environment. Ecometric trait distributions are thus a comparatively universal metric for exploring systems dynamics at all scales. The main challenge now is to move beyond investigating how future climate change will affect the distribution of organisms and how it will impact ecosystem services and to shift the perspective to ask how biotic systems interact with changing climate in general, and how climate change affects the interactions within and between the components of the whole biotic-physical system. We believe that it is possible to provide believable, quantitative answers to these questions. Because of this we have initiated an IUBS program iCCB (integrative Climate Change Biology). 相似文献
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44.
Aysin Dural Erem Gulay Ozcan Mikael Skrifvars Mukerrem Cakmak 《Fibers and Polymers》2013,14(9):1415-1421
In this study, the preparation method and characteristics of silver (Ag) nanoparticle (NP) loaded polyamide 6 (PA6) nanocomposite and its antimicrobial activity against Klebsiella pneumonia and Staphylococcus aureus were investigated. The melt intercalation method was used to prepare a series of PA 6 nanocomposite fibers containing, 0; 1; 3; 5 % (wt.) Ag. PA6/Ag nanocomposite fibers exhibit increased antimicrobial efficiency with the increase of nanoparticle contents. On the other hand, thermal characterization tests show that the increased concentration of Ag nanoparticles reduces the mechanical properties due to their partial agglomeration leading to flaw generation. The crystallinity of the fibers was found to decrease about 10 % with increase of Ag to 5 %. This was attributed to faster cooling rate experienced in the presence of high thermal conductivity Ag particles. 相似文献
45.
Arkkola T Uusitalo U Kronberg-Kippilä C Männistö S Virtanen M Kenward MG Veijola R Knip M Ovaskainen ML Virtanen SM 《Public health nutrition》2008,11(2):176-182
OBJECTIVES: To identify and describe dietary patterns in a cohort of pregnant women and investigate whether the dietary patterns are associated with dietary intake and sociodemographic factors. DESIGN: Mothers entering the Finnish Type 1 Diabetes Prediction and Prevention (DIPP) Nutrition Study in 1997-2002 were retrospectively asked to complete a food-frequency questionnaire concerning their diet during pregnancy. Principal components analysis was used to identify dietary patterns. SETTING: Finland. SUBJECTS: Subjects were 3730 women with a newborn infant carrying increased genetic susceptibility to type 1 diabetes mellitus. RESULTS: Seven factors were identified and named. Energy intake correlated positively with 'Healthy', 'Fast food', 'Traditional bread', 'Traditional meat' and 'Coffee' patterns and inversely with the 'Alcohol and butter' pattern. Intake of dietary fibre correlated positively with 'Healthy', 'Traditional bread' and 'Low-fat foods' patterns and inversely with the 'Alcohol and butter' pattern. The seven dietary patterns seemed to account for relatively large proportions of the variance in energy and nutrient intakes except for the intake of vitamin D, vitamin C, carotenoids and calcium. Maternal age and higher level of education were associated with higher scores on 'Healthy', 'Low-fat foods' and 'Alcohol and butter' patterns. CONCLUSION: Principal components analysis produced seven dietary patterns which may be useful for further research concerning maternal diet and health outcomes among both mothers and their offspring. 相似文献
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47.
Single walled carbon nanotubes (SWNTs) are considered as a highly potential reinforcement material for the epoxy composites. Dispersion of SWNTs in epoxy and poor interfacial strain transfer are two major challenges. Surface functionalization is one efficient way to change the dispersion and interfacial properties of SWNTs. In this study, five different modification methods of SWNTs were used, and the functional groups on the SWNTs were tested by X-ray photoelectron spectroscopy and Raman spectroscopy. The SWNTs/epoxy composite were prepared using dimethylformamide (DMF) as the solvent. SWNTs at two concentration levels of 0.05 wt% and 0.5 wt% and with five different surface modifications were filled in to epoxy resins. The dispersion of the nanotubes in epoxy resin was evaluated by light optical microscope (LOM), with high content of SWNTs more aggregates appear. The interfacial strain transfer was tested by Raman shift of the 2D band when applying a strain on the epoxy composite sample. With equal strain levels in the composite more strain was transferred from epoxy matrix to SWNTs with 0.05 wt% of SWNTs than the 0.5 wt% of SWNTs filled epoxy resin. Mechanical properties were influenced by the strain transfer efficiency and the curing degree of the samples. 相似文献
48.
Alexandra F. Marques Jorge P. de Sousa Mikael Rönnqvist Ricardo Jafe 《Scandinavian Journal of Forest Research》2014,29(7):166-177
The use of optimization techniques is well established in forest short-term planning and decision-making. Yet, existing techniques may pose some limitations for tackling with stochastic factors impacting in the execution of forest operations, such as delays, equipment breakdowns and other unexpected events. This paper explores the potential of using optimization techniques in combination with discrete-event simulation (DES) models for planning harvesting and logistics operations acknowledging uncertainty. DES models may be useful for assessing the performance and identifying bottlenecks associated with the execution of the deterministic plans retrieved with optimization techniques, when such stochastic events occur. This paper further presents an approach for the combination of a heuristic and a DES model developed in SIMIO. This approach was used to solve the raw material reception problem (RMRP) at a Portuguese pulp mill. This paper concludes with the analysis of the performance of deterministic schedules for the wood trucks considering uncertainty in their arrival at the mill. 相似文献
49.
Organic food standardization is an increasingly important strategy for dealing with consumer concerns about the environment, animal welfare, health, and the economic structure of food production. But the ways in which this consumer-oriented strategy is introduced, organized, and debated vary considerably across countries. In Sweden, a nongovernmental organization [KRAV (Association for Control of Organic Production)] – consisting of social movement organizations, associations for conventional and organic farmers, and the food industry – has been quite successful in promoting organic food labeling as an eco-label. KRAV has developed a complementary position vis-à-vis the state and EU regulatory framework. In the US, the federal government controls standardization. The government frames the label as a “marketing label,” thus rejecting the idea that organic food production would have any significant advantages for the environment or, indirectly, for human health. This framing is separate from the ones created by organic constituencies, leading to deeper controversies than in Sweden. The purpose of this paper is to examine why standardization has followed different patterns in the two settings. We analyze context factors (i.e., political culture, pre-regulatory arrangements, and organizational structures) and process factors (i.e., framing and organizing). What are the benefits of a state-centric versus a nonstate-driven approach regarding powerful standardization? The paper shows that both settings provide not only “threats of regulatory occupation” from actors not committed to organic principles but also avenues for substantial standardization in the future, albeit through different channels. 相似文献
50.
Timo J. Ruokonen Tapio Keskinen Mikael Luoma Ari Leskelä Petri Suuronen 《Fisheries Management and Ecology》2021,28(3):211-218
Trap fisheries can provide catches of high quality, and unwanted bycatch can be released with high survival. Light attraction could be an effective way of increasing trap catches, but research results are largely lacking. Experiments to test the effect of LED lights in trap-net fishing were conducted in two Finnish lakes where fishing targeted Eurasian perch Perca fluviatilis L. and roach Rutilus rutilus (L.). LED lights (white, green, red, blue and combinations) were attached inside the traps. The use of LED lights did not increase fish CPUE. Contrary to expectation, Eurasian perch catches were higher in traps without LED lights. Significant variation in CPUEs was observed, but without interaction with light treatments. The LED lights tested in this study do not increase the effectiveness of trap fishery targeting Eurasian perch and roach in Finnish lakes in the ice-free season. 相似文献