Scale Model of a Soil Aggregate and Associated Organisms: A Teaching Tool for Soil Ecology

Soil is a complex habitat for diverse biota. A significant challenge in teaching soil ecology is our inability to observe organisms as they live and interact in the soil. The objective of this article is to describe an interactive class project to help students visualize the sizes of different groups of soil organisms and to relate these to soil structural components. This project was carried out by students in an upper-level undergraduate soil ecology class. It involved the design and construction of a 4000× scale model of a soil aggregate and its associated organisms. The body of the model was made from inexpensive, lightweight materials and had a diameter of approximately 1 m to depict a 0.25-mm aggregate. Students identified and discussed appropriate size ranges and construction materials for the model’s bacteria, fungi, nematodes, mites, springtails, and other components. Instructor-guided questions addressed size and arrangement of sand, silt, and clay particles; pores; and organic matter in a typical soil aggregate. The model is a useful tool for conveying physical and ecological relationships among soil organisms and is adaptable for use at diverse educational levels

Gauge invariance in two-particle scattering

It is shown how gauge invariance is obtained for the coupling of a photon to a two-body state described by the solution of the Bethe-Salpeter equation. This is illustrated both for a complex scalar field theory and for interaction kernels derived from chiral effective Lagrangians.Comment: 16 pages, 2 figures, references added and commented o

How does a successful Norwegian incubator practice learning? - A case study of Validé

Incubators have a purpose of increasing the success rate of start-up companies and entrepreneurs. Several countries, including Norway, have invested in the development of innovation as this is acknowledged to be a key contributing factor to nations’ economies. Studying successful incubators may provide useful information on how other incubators can improve. As research has shown, incubators may function differently depending on the culture they operate in. Little research has been done on learning within incubators in a Norwegian context. Therefore, this thesis studies a successful Norwegian incubator and how they practice learning with the purpose of identifying key factors for their success. This single case study compares existing literature on knowledge, learning, and incubation with findings from qualitative interviews with employees working in the incubator department in the Norwegian innovation company Validé. Seven business advisors, a fund director, and the CEO of the company were interviewed. Comparisons between literature and findings from the interviews showed that learning takes place in a variety of different ways in Validé. This study suggests that key factors to Validé's success include close collaboration between colleagues, openness and transparency in the organization, low internal competitiveness, engaged and active leadership, and a strong organizational culture. This study also points out other factors that are difficult for other incubators to copy. Findings show that factors such as current resources, historical point in time, and location may have an effect on the incubator's success.Incubators have a purpose of increasing the success rate of start-up companies and entrepreneurs. Several countries, including Norway, have invested in the development of innovation as this is acknowledged to be a key contributing factor to nations’ economies. Studying successful incubators may provide useful information on how other incubators can improve. As research has shown, incubators may function differently depending on the culture they operate in. Little research has been done on learning within incubators in a Norwegian context. Therefore, this thesis studies a successful Norwegian incubator and how they practice learning with the purpose of identifying key factors for their success. This single case study compares existing literature on knowledge, learning, and incubation with findings from qualitative interviews with employees working in the incubator department in the Norwegian innovation company Validé. Seven business advisors, a fund director, and the CEO of the company were interviewed. Comparisons between literature and findings from the interviews showed that learning takes place in a variety of different ways in Validé. This study suggests that key factors to Validé's success include close collaboration between colleagues, openness and transparency in the organization, low internal competitiveness, engaged and active leadership, and a strong organizational culture. This study also points out other factors that are difficult for other incubators to copy. Findings show that factors such as current resources, historical point in time, and location may have an effect on the incubator's success

Post-training load-related changes of auditory working memory: An EEG study

Working memory (WM) refers to the temporary retention and manipulation of information, and its capacity is highly susceptible to training. Yet, the neural mechanisms that allow for increased performance under demanding conditions are not fully understood. We expected that post-training efficiency in WM performance modulates neural processing during high load tasks. We tested this hypothesis, using electroencephalography (EEG) (N = 39), by comparing source space spectral power of healthy adults performing low and high load auditory WM tasks. Prior to the assessment, participants either underwent a modality-specific auditory WM training, or a modality-irrelevant tactile WM training, or were not trained (active control). After a modality-specific training participants showed higher behavioral performance, compared to the control. EEG data analysis revealed general effects of WM load, across all training groups, in the theta-, alpha-, and beta-frequency bands. With increased load theta-band power increased over frontal, and decreased over parietal areas. Centro-parietal alpha-band power and central beta-band power decreased with load. Interestingly, in the high load condition a tendency toward reduced beta-band power in the right medial temporal lobe was observed in the modality-specific WM training group compared to the modality-irrelevant and active control groups. Our finding that WM processing during the high load condition changed after modality-specific WM training, showing reduced beta-band activity in voice-selective regions, possibly indicates a more efficient maintenance of task-relevant stimuli. The general load effects suggest that WM performance at high load demands involves complementary mechanisms, combining a strengthening of task-relevant and a suppression of task-irrelevant processing

Equity-Efficiency Optimizing Resource Allocation: The Role of Time Preferences in a Repeated Irrigation Game

We study repeated water allocation decisions among small scale irrigation users in Tanzania. In a treatment replicating water scarcity conditions, convexities in production make that substantial efficiency gains can be obtained by deviating from equal sharing, leading to an equity–efficiency trade-off. In a repeated game setting, it becomes possible to reconcile efficiency with equity by rotating the person who receives the largest share, but such a strategy requires a longer run perspective. Correlating experimental data from an irrigation game with individual time preference data, we find that less patient irrigators are less likely to use a rotation strategy

Experimental Determination Of Relative Signs Of Dipole Moment Derivatives: Hcn And Dcn

An alternative numerical analysis for the experimental determination of the relative signs of the dipole moment derivatives with respect to the normal coordinates is presented. Use is made of the polar tensor and effective charge equations and the G-intensity sum rule of Crawford. The relative signs are determined by sufficiently accurate individual infrared fundamental intensities of one molecule and only the sum of these intensities for an isotopically related molecule. The intensity data of HCN and DCN are used to illustrate the procedure. The as yet unreported values of the atomic polar tensors and effective charges of these molecules are also reported. © 1978 American Institute of Physics.68384785

Governance for integrated water resources management in a river-basin context: proceedings of a regional seminar, Bangkok, May, 2002

Water resource management / River basins / Governance / Institutional development / Groundwater irrigation / Water policy / Water allocation / Water demand / Irrigation efficiency / Models / Case studies

F And G Intensity Sum Rule Applications: The Chxd4-x Molecules

Numerical analyses based on the F and G intensity sum rules show that recently published experimental values for the fundamental vibrational intensities of CH4, CH3D, CH2D2, CHD3, and CD4 are internally consistent within experimental errors. Effective charge values for the carbon and hydrogen atoms obtained using the intensity sums for all these isotopically related molecules are almost in exact agreement with reported values obtained from the polar tensors of CH4 and CD4. The G sum rule allows a determination of the signs of the dipole moment derivatives using the fundamental intensity sum for CH4 (or CD4) and the polar tensor values for CD4 (or CH4). © 1978 American Institute of Physics.6994147414