title: Nitrogen losses from soils caused by Rhizobium-dependent denitrification

authors: O'Hara, G.W.

subjects: biology

abstract: Biological nitrogen fixation by the Rhizobium-legume symbiosis is of considerable agronomic importance, and most research on rhizobia is aimed at a better understanding of symbiotic nitrogen fixation (e.g. Hardy er nl.. 1979; Hardy and Silver. 1977: Hardv and Gibson. 1977). However the d I significance of early observations on denitrification by rhizobia (Rajagopalan, 1938; Ishizawa, 1939; Wilson, 1947) appears to have been overlooked; it has recently been shown to be widespread among Rhizobium species (Zablotowicz et al., 1978; Daniel ef al., 1980a. 1982) and to occur in soils under laboratory conditions (Daniel el al., 1980b). We report here field experiments showing the loss of fixed nitrogen from soils by denitrification carried out by rhizobia at rates comparable to those at which rhizobia fix nitrogen. This occurs in aerated soils, unlike previously described soil denitrification systems which are considered to be anaerobic (Knowles, 1982). Rhizobia are widespread in agricultural ecosystems (Parker et al., 1977) and an understanding of the conditions under which they denitrify may convey substantial benefits.

text: Nitrogen losses from soils caused by Rhizobium-dependent denitrification Biological nitrogen fixation by the Rhizobium-legume symbiosis is of considerable agronomic importance, and most research on rhizobia is aimed at a better understanding of symbiotic nitrogen fixation (e.g. Hardy er nl.. 1979; Hardy and Silver. 1977: Hardv and Gibson. 1977). However the d I significance of early observations on denitrification by rhizobia (Rajagopalan, 1938; Ishizawa, 1939; Wilson, 1947) appears to have been overlooked; it has recently been shown to be widespread among Rhizobium species (Zablotowicz et al., 1978; Daniel ef al., 1980a. 1982) and to occur in soils under laboratory conditions (Daniel el al., 1980b). We report here field experiments showing the loss of fixed nitrogen from soils by denitrification carried out by rhizobia at rates comparable to those at which rhizobia fix nitrogen. This occurs in aerated soils, unlike previously described soil denitrification systems which are considered to be anaerobic (Knowles, 1982). Rhizobia are widespread in agricultural ecosystems (Parker et al., 1977) and an understanding of the conditions under which they denitrify may convey substantial benefits.

year: 1984

title: Approximative filtering of XML documents in a publish/subscribe system

authors: Hinze, Annika

subjects: computer science

abstract: Publish/subscribe systems filter published documents and inform their subscribers about documents matching their interests. Recent systems have focussed on documents or messages sent in XML format. Subscribers have to be familiar with the underlying XML format to create meaningful subscriptions. A service might support several providers with slightly differing formats, e.g., several publishers of books. This makes the definition of a successful subscription almost impossible. This paper proposes the use of an approximative language for subscriptions. We introduce the design of our ApproXFilter algorithm for approximative filtering in a publish/subscribe system. We present the results of our performance analysis of a prototypical implementation.

text: Approximative filtering of XML documents in a publish/subscribe system Publish/subscribe systems filter published documents and inform their subscribers about documents matching their interests. Recent systems have focussed on documents or messages sent in XML format. Subscribers have to be familiar with the underlying XML format to create meaningful subscriptions. A service might support several providers with slightly differing formats, e.g., several publishers of books. This makes the definition of a successful subscription almost impossible. This paper proposes the use of an approximative language for subscriptions. We introduce the design of our ApproXFilter algorithm for approximative filtering in a publish/subscribe system. We present the results of our performance analysis of a prototypical implementation.

year: 2006-01-16

title: An integral rite of passage: embedding the aesthetic in adventure education in the pursuit of wellbeing

authors: Wagstaff, Ruth

subjects: wellbeing

abstract: The context for this study was the implementation of an arts integrated unit examined through the lenses of wellbeing, adventure education, children’s spirituality and aesthetic experience. The author’s personal experiences as a holistic educator, connecting theory and practice in educational settings, informed the devising of the learning experiences incorporated into this contemporary ‘Rites of Passage’, arts integrated unit. They also informed the qualitative methods selected for this research. Students reported on their own and others’ perceived state of “wholeness” and completeness of experience and the New Zealand Maori concepts of “hauora” – mental and emotional, physical, social and spiritual wellbeing were examined. Qualitative analysis of the data revealed that a holistic, integrative approach to learning was valued by the students and contributed significantly to their experience of wellbeing and wholeness. The coded data was considered in terms of a heuristic clustering of responses around the relational categories of Self, Others and the Environment. Connection, Relationship and Belonging emerged as the most important themes and, unexpectedly, Inclusion emerged as an important consideration to the participants in this study. Creative and resilience-building learning activities, as within this ‘Rites of Passage” unit and the integral “Wilderness Camp”, are supportive of the health and wellbeing of young learners. Such learning opportunities provide for intra-personal and inter-personal development, and contribute to their sense of self, place, meaning and purpose.

text: An integral rite of passage: embedding the aesthetic in adventure education in the pursuit of wellbeing The context for this study was the implementation of an arts integrated unit examined through the lenses of wellbeing, adventure education, children’s spirituality and aesthetic experience. The author’s personal experiences as a holistic educator, connecting theory and practice in educational settings, informed the devising of the learning experiences incorporated into this contemporary ‘Rites of Passage’, arts integrated unit. They also informed the qualitative methods selected for this research. Students reported on their own and others’ perceived state of “wholeness” and completeness of experience and the New Zealand Maori concepts of “hauora” – mental and emotional, physical, social and spiritual wellbeing were examined. Qualitative analysis of the data revealed that a holistic, integrative approach to learning was valued by the students and contributed significantly to their experience of wellbeing and wholeness. The coded data was considered in terms of a heuristic clustering of responses around the relational categories of Self, Others and the Environment. Connection, Relationship and Belonging emerged as the most important themes and, unexpectedly, Inclusion emerged as an important consideration to the participants in this study. Creative and resilience-building learning activities, as within this ‘Rites of Passage” unit and the integral “Wilderness Camp”, are supportive of the health and wellbeing of young learners. Such learning opportunities provide for intra-personal and inter-personal development, and contribute to their sense of self, place, meaning and purpose.

year: 2011