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Tom Flanagan Janet McIntyre-Mills Tony Made Kelly Mackenzie Charles Morse Gayle Underwood Ken Bausch 《Systemic Practice and Action Research》2012,25(2):171-193
Sustainability is not simply about changing practices but more centrally about agreeing to change practices together. To achieve
such an end, groups need to improve processes for making complex decisions together. An online course was designed and tested
linking students in the United States and in Australia. Students engaged in a re-enactment of deliberations based on Hasan
Ozbekhan’s “Predicament of Mankind,” which was constructed originally under assignment from the founders of the Club of Rome
in 1970. This re-enactment included contemporary research for examples of a set of 49 continuous critical problems of mankind,
asynchronous clarification of these problems using a wiki, pair-wise construction of a systems view of problems assessed to
be of highest priority by the class, narrative analysis of the structure, and creative suggestions for resolving the systems
problem based on resources available today. This report comments on the strengths and challenges identified in an initial
application of an approach for building collaborative and systems thinking skills through an online course in a general education
curriculum. Findings are particularly meaningful for contemporary policy makers as well as online educators. 相似文献
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Western juniper ( Juniperus occidentalis spp. occidentalis Hook.) expansion in the northern Great Basin has reduced shrubsteppe productivity and diversity. Chainsaw cutting of western juniper woodlands is commonly applied to remove tree interference and restore sagebrush plant communities. Studies assessing understory response following cutting have been limited to early successional stages and have not evaluated the effects of western juniper debris on plant succession. Cutting western juniper produces a large amount of debris which is commonly left on site, occupying a significant portion of treated areas. This study evaluated successional dynamics spanning 13 years after western juniper cutting. Four 0.45-ha blocks were selected on Steens Mountain in southeastern Oregon. Western juniper cover averaged 26% and mature tree density averaged 250 trees ? ha –1 . Blocks were cut in late summer 1991. Understory standing crop, cover, and density were compared among 3 locations: old canopy litter mats (canopy), interspace, and area underneath cut western juniper (debris). In the interspace, perennial grasses increased in cover and in standing crop relative to other functional groups. In canopy and debris locations, species composition shifted in the 6th year after cutting as annual grass cover, density, and standing crop increased. However, by 2003, perennial grass biomass was 2 times greater than annual grass biomass in canopy and debris locations. Because annual grasses increased in areas of debris accumulation, managers need to be cognizant of western juniper treatments that create safe sites that are favorable to the establishment of weedy species. Retaining western juniper debris on this site did not increase establishment and growth of perennial grasses compared to the interspace. A shift in perennial grass dominance from Thurber's needlegrass ( Achnatherum thurberianum [Piper] Barkworth) to bottlebrush squirreltail ( Elymus hystrix [Nutt.] Smith) occurred in areas of debris accumulation. Our results demonstrated that long-term vegetation evaluations are necessary to properly assess management activities and disturbance. 相似文献
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Nielsen PR Nietlispach D Mott HR Callaghan J Bannister A Kouzarides T Murzin AG Murzina NV Laue ED 《Nature》2002,416(6876):103-107
Specific modifications to histones are essential epigenetic markers---heritable changes in gene expression that do not affect the DNA sequence. Methylation of lysine 9 in histone H3 is recognized by heterochromatin protein 1 (HP1), which directs the binding of other proteins to control chromatin structure and gene expression. Here we show that HP1 uses an induced-fit mechanism for recognition of this modification, as revealed by the structure of its chromodomain bound to a histone H3 peptide dimethylated at Nzeta of lysine 9. The binding pocket for the N-methyl groups is provided by three aromatic side chains, Tyr21, Trp42 and Phe45, which reside in two regions that become ordered on binding of the peptide. The side chain of Lys9 is almost fully extended and surrounded by residues that are conserved in many other chromodomains. The QTAR peptide sequence preceding Lys9 makes most of the additional interactions with the chromodomain, with HP1 residues Val23, Leu40, Trp42, Leu58 and Cys60 appearing to be a major determinant of specificity by binding the key buried Ala7. These findings predict which other chromodomains will bind methylated proteins and suggest a motif that they recognize. 相似文献
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This paper presents a personal account of the theory and practice of staff development of Open University (OU) tutorial staff, based on nearly 30 years' experience, during which I have consciously reflected on my work, continually building on what has seemed important. It results from an extensive process of reflection in which I have tried to capture an understanding of what I do, with the aid of systems models. Some of the basic assumptions and systems models I present have more or less stood the test of time for a number of years; others are the result of my latest reflections. I show how I have used systems concepts and methods to form a coherent, holistic framework for developing tutorial staff in the East Anglian Region of the OU. Two aspects of this work are emphasized: first, the role that staff development can play in improving tutors' basic skills and understanding of their role; second, how the quality of their work is managed through using feedback and the notions of single- and double-loop learning. An important feature of this work has been the setting-up of communities of practice which enable learning by individual tutors to be shared with their peers and transformed into organizational learning for general use. Starting with some basic assumptions about staff development, a number of systemic models are presented which fit into a coherent framework, linking theory to practice and embodying Rene Dubos' (1972) well-known dictum to "Think globally, act locally." 相似文献
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