The CGIAR and National Agricultural Research Systems

A consultant study presented at TAC 76 by Hans Gregersen, after wide consultation, on relationships between CGIAR centers and national agricultural research systems (NARS). The latter were broadly defined to include not only national agricultural research institutes (NARIs), but also universities, NGOs, the private sector, extension agencies, and various farmers organizations. Gregersen pointed out that NARS differed greatly among themselves, as did the relationships among the various institutions within any country. He considered various relationships including but not limited to, partnerships.The report recommended that TAC further assess CGIAR-NARS collaborative research efforts, including appraisal of the various modalities of collaboration, assessment of the relative strengths of NARS and of the comparative advantage of centers, differing priorities between centers and NARS, and improvements of information flows. The role of regional organizations, and CGIAR systemwide activities should be considered. Gregersen urged preparation of a TAC strategy paper on promising avenues for strengthening relationships, taking account of changing research management and funding environments

AGROFORESTRY POLICIES CONTRIBUTE TO SUSTAINABLE LAND USE

Resource /Energy Economics and Policy,

IMPROVING PROJECT MANAGEMENT FOR SUSTAINABLE DEVELOPMENT

Institutional and Behavioral Economics,

Simulations of Myenteric Neuron Dynamics in Response to Mechanical Stretch

Background. Intestinal sensitivity to mechanical stimuli has been studied intensively in visceral pain studies. The ability to sense different stimuli in the gut and translate these to physiological outcomes relies on the mechanosensory and transductive capacity of intrinsic intestinal nerves. However, the nature of the mechanosensitive channels and principal mechanical stimulus for mechanosensitive receptors are unknown. To be able to characterize intestinal mechanoelectrical transduction, that is, the molecular basis of mechanosensation, comprehensive mathematical models to predict responses of the sensory neurons to controlled mechanical stimuli are needed. This study aims to develop a biophysically based mathematical model of the myenteric neuron with the parameters constrained by learning from existing experimental data. Findings. The conductance-based single-compartment model was selected. The parameters in the model were optimized by using a combination of hand tuning and automated estimation. Using the optimized parameters, the model successfully predicted the electrophysiological features of the myenteric neurons with and without mechanical stimulation. Conclusions. The model provides a method to predict features and levels of detail of the underlying physiological system in generating myenteric neuron responses. The model could be used as building blocks in future large-scale network simulations of intrinsic primary afferent neurons and their network

Priorities and Strategies for Soil and Water Aspects of Natural Resources Management Research in the CGIAR

Report of a TAC study on priorities for the soil and water aspects of research on natural resource management (NRM) research in the CGIAR, completed in April 1996 under the leadership of TAC members Hans Gregersen and Ted Henzell. The study is supported by background reports on a strategic review of NRM research on soil and water, and a synthesis of current activities in soil and water research in the CGIAR. The document also contains an extract from the proceedings of the CGIAR meeting in May 1996, and a transmittal from the TAC Chairman.The paper conveys TAC's views on the needs for soil and water research in the CGIAR and the mechanisms for meeting those needs. It says that strengthening research on environmental issues is needed, but linked to the CGIAR vision of contributing to poverty alleviation and sustainable food security. Other goals of NRM research should be considered as well. The balance of effort should be shifted from location specific studies to results transferable among developing countries. The centers should play an active but limited role in generating information on the condition of the natural environment, and the impact of humans on that environment. The CGIAR needed an integrated framework for NRM research, and within that framework to focus on specific subject matter. Water in particular was cited as needing more emphasis. The paper called for uniform and consistent criteria for judging CGIAR priorities for NRM activities and research. The study was requested by the Group at the CGIAR Mid Term Meeting, May 1994, and was initiated at TAC 65 in October 1994. The evolving study was considered at TAC 66, 67, 68, and 69. It was presented at the CGIAR Mid Term Meeting in May 1996

Phasic and Tonic Smooth Muscle Function of the Partially Obstructed Guinea Pig Intestine

This study was to generate phasic and tonic stress-strain curves for evaluation of smooth muscle function in the obstructed guinea pig jejunum. Partial and sham obstruction of the jejunum in guinea pigs was created surgically, with guinea pigs not being operated on served as normal controls. The animals survived 2, 4, 7, and 14 days, respectively. The jejunal segment was distended to 10 cm H2O. The pressure and outer diameter changes were recorded. Passive conditions were obtained by using papaverine. Total phasic, tonic, and passive circumferential stress and strain were computed from the diameter and pressure data with reference to the zero-stress-state geometry. The active phasic and tonic stresses were defined as the total phasic and tonic stress minus the passive stress. The thickness of intestinal muscle layers increased in a time-dependent manner after obstruction. The amplitude of passive, total phasic, total tonic, active phasic, and active tonic circumferential stresses increased as function of strain 7 days after obstruction. However, when normalized to muscle layer thickness, the amplitude of active stresses did not differ among the groups. In conclusion, the long-term-obstructed intestine exhibits increased total smooth muscle contraction force. However, the contraction force per smooth muscle unit did not increase