scholarly journals How does overstory retention affect above- and below-ground resource availability and seedling performance?: implications for silvicultural systems choice in the ESSF

2000 ◽  
Author(s):  
Cleo C Lajzerowicz
2015 ◽  
Vol 282 (1806) ◽  
pp. 20150327 ◽  
Author(s):  
Martin Weiser ◽  
Jan Smyčka

Plant clonal spread is ubiquitous and of great interest, owing both to its key role in plant community assembly and its suitability for plant behaviour research. However, mechanisms that govern spreading distance are not well known. Here we link spacer costs and below-ground competition in a simple model of growth in a homogeneous below-ground environment, in which optimal distance between ramets is based on minimizing the sum of these costs. Using this model, we predict a high prevalence of clonal growth that does not employ spacers in resource-poor environments and a nonlinear increase in spreading distance in response to increasing below-ground resource availability. Analysis of database data on clonal growth in relationship to below-ground resource availability revealed that patterns of the spread based on stolons is compatible with the model's predictions. As expected, model prediction failed for rhizomatous species, where spacer sizes are likely to be selected mainly to play roles other than spread. The model's simplicity makes it useful as a null model in testing hypotheses about the effects of environmental heterogeneity on clonal spread.


GeroPsych ◽  
2014 ◽  
Vol 27 (4) ◽  
pp. 171-179 ◽  
Author(s):  
Laurence M. Solberg ◽  
Lauren B. Solberg ◽  
Emily N. Peterson

Stress in caregivers may affect the healthcare recipients receive. We examined the impact of stress experienced by 45 adult caregivers of their elderly demented parents. The participants completed a 32-item questionnaire about the impact of experienced stress. The questionnaire also asked about interventions that might help to reduce the impact of stress. After exploratory factor analysis, we reduced the 32-item questionnaire to 13 items. Results indicated that caregivers experienced stress, anxiety, and sadness. Also, emotional, but not financial or professional, well-being was significantly impacted. There was no significant difference between the impact of caregiver stress on members from the sandwich generation and those from the nonsandwich generation. Meeting with a social worker for resource availability was identified most frequently as a potentially helpful intervention for coping with the impact of stress.


2018 ◽  
pp. 76-89
Author(s):  
E. M. Avraamova ◽  
V. N. Titov

The analysis of present-time directions in the study of social development has allowed to identify the resource approach as the most productive one which enables to assess social dynamics through the range of resource characteristics of different population groups and abilities of the relevant groups to apply development resources in the current economic and institutional conditions. Basing on the sociological survey conducted by ISAP RANEPA, the quantitative estimation of material and social recourses of the population has been made; integral values of the resource potential have been calculated as well. The issues of social structure formation are analyzed through the aspect of resource availability; the barriers of Russian middle-class enlargement are defined.


2018 ◽  
Vol 20 (1) ◽  
pp. 127
Author(s):  
Tianduo Peng ◽  
Zhiyi Yuan ◽  
Jiehui Yuan ◽  
Xufeng Zhu ◽  
Xunmin Ou

2020 ◽  
Vol 18 (4) ◽  
pp. 122-131
Author(s):  
Vadim F. Islamutdinov ◽  
Sergey P. Semenov

The purpose of the study is to develop a model for the co-evolution of the regional economy and economic institutions. The research methods used: abstract-logical for the study of theoretical aspects and the experience of modeling co-evolution; and economic-mathematical for the development of own model of coevolution. The results of the study: approaches to modeling the evolution of economic institutions, as well as the co-evolution of the regional economy and economic institutions are considered, strengths and weaknesses of existing approaches to modeling co-evolution are identified, on the basis of the logistic model and Lotka-Volterra equations, an own co-evolution model has been developed, which includes three entities: regional economy, “good” institution and “bad” institution. Three versions of the model have been developed: the co-evolution of the regional economy and the “good” institution, the co-evolution of the regional economy and the “bad institution,” and a variant of the co-evolution of all three entities simultaneously, in which the “good” and “bad” institutions interact according to the “predator-prey” model, and their the cumulative effect determines the development of the regional economy. Numerical experiments have been carried out in the MathLab, which have shown the capabilities of the model to reflect the results of the co-evolution of the economy of a resource-producing region and economic institutions. In the first variant, a “good” institution promotes economic growth in excess of the level determined by resource availability. In the second variant, the “bad” institution has a disincentive effect on the GRP, as a result of which the GRP falls below the level determined by the resource endowment. In the third variant, the interaction of “good” and “bad” institutions still contributes to economic growth above the level determined by resource availability, but causes cyclical fluctuations in the GRP.


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