Integrating agroforestry intercropping systems in intensive agricultural landscapes: a SWOT-AHP analysis of stakeholders perceptions

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Scattering Mechanism in Modulation-Doped Shallow Two-Dimensional Electron Gases

We report on a systematic investigation of the dominant scattering mechanism in shallow two-dimensional electron gases (2DEGs) formed in modulation-doped GaAs/Al_{x}Ga_{1-x}As heterostructures. The power-law exponent of the electron mobility versus density, mu \propto n^{alpha}, is extracted as a function of the 2DEG's depth. When shallower than 130 nm from the surface, the power-law exponent of the 2DEG, as well as the mobility, drops from alpha \simeq 1.65 (130 nm deep) to alpha \simeq 1.3 (60 nm deep). Our results for shallow 2DEGs are consistent with theoretical expectations for scattering by remote dopants, in contrast to the mobility-limiting background charged impurities of deeper heterostructures.Comment: 4 pages, 3 figures, modified version as accepted in AP

Agricultural, forest and rural policy sectors' receptiveness to agroforestry intercropping systems in Quebec (Canada)

PosterIn Quebec (Canada), intercropping trees and crops is a new practice in the agricultural landscape dominated by conventional monocropping systems. As research goes on and slowly reveals the potential of these systems to address some key issues in agriculture, forestry and rural development, and as farmers’ awareness increases, there is a pressing need to find public support for these systems. In order to help the promoters of agroforestry intercropping systems in their search of support in the political arena, we conducted a comparative study of the receptiveness of the agricultural, forest and rural policy sectors to these systems. As the literature on public policy processes has stressed the importance of policy stakeholders’ ideas in the implementation of new policies, we used a conceptual framework based on cognitive schemes to compare the ideas driving these policy sectors with the ideas supporting agroforestry intercropping systems. Results based on the analysis of formal publications and semi-directed interviews conducted with agroforestry experts and policy stakeholders underline that agroforestry intercropping systems are mostly featured by their promoters as sustainable and multifunctional systems. The rural policy sector has proven to be the most receptive and the forest sector the less receptive, while the agricultural sector lies in-between, offering small-scale support to agroforestry intercropping systems. The analysis highlights that policy sectors integrating multifunctionality in their core ideas are supportive of agroforestry intercropping systems, while sectors remaining largely focused on specialization and productivity are less receptive. Our study also shows that public incentives might not be sufficient to drive the adoption of agroforestry intercropping systems since major barriers to their implementation remain in some policy sectors. Featuring these systems as productive might be a necessary argument shift to tear down policy barriers and increase public support

Handling Temperature Bursts Reaching 464 C: Different Microbial Strategies in the Sisters Peak Hydrothermal Chimney

The active venting Sisters Peak (SP) chimney on the Mid-Atlantic Ridge holds the current temperature record for the hottest ever measured hydrothermal fluids (400 degrees C, accompanied by sudden temperature bursts reaching 464 degrees C). Given the unprecedented temperature regime, we investigated the biome of this chimney with a focus on special microbial adaptations for thermal tolerance. The SP metagenome reveals considerable differences in the taxonomic composition from those of other hydrothermal vent and subsurface samples; these could be better explained by temperature than by other available abiotic parameters. The most common species to which SP genes were assigned were thermophilic Aciduliprofundum sp. strain MAR08-339 (11.8%), Hippea maritima (3.8%), Caldisericum exile (1.5%), and Caminibacter mediatlanticus (1.4%) as well as to the mesophilic Niastella koreensis (2.8%). A statistical analysis of associations between taxonomic and functional gene assignments revealed specific overrepresented functional categories: for Aciduliprofundum, protein biosynthesis, nucleotide metabolism, and energy metabolism genes; for Hippea and Caminibacter, cell motility and/or DNA replication and repair system genes; and for Niastella, cell wall and membrane biogenesis genes. Cultured representatives of these organisms inhabit different thermal niches; i.e., Aciduliprofundum has an optimal growth temperature of 70 degrees C, Hippea and Caminibacter have optimal growth temperatures around 55 degrees C, and Niastella grows between 10 and 37 degrees C. Therefore, we posit that the different enrichment profiles of functional categories reflect distinct microbial strategies to deal with the different impacts of the local sudden temperature bursts in disparate regions of the chimney

Observation of gravity-capillary wave turbulence

We report the observation of the cross-over between gravity and capillary wave turbulence on the surface of mercury. The probability density functions of the turbulent wave height are found to be asymmetric and thus non Gaussian. The surface wave height displays power-law spectra in both regimes. In the capillary region, the exponent is in fair agreement with weak turbulence theory. In the gravity region, it depends on the forcing parameters. This can be related to the finite size of the container. In addition, the scaling of those spectra with the mean energy flux is found in disagreement with weak turbulence theory for both regimes

Formation and transportation of sand-heap in an inclined and vertically vibrated container

We report the experimental findings of formation and motion of heap in granular materials in an inclined and vertically vibrated container. We show experimentally how the transport velocity of heap up container is related to the driving acceleration as well as the driving frequency of exciter. An analogous experiment was performed with a heap-shaped Plexiglas block. We propose that cohesion force resulted from pressure gradient in ambient gas plays a crucial role in enhancing and maintaining a heap, and ratchet effect causes the movement of the heap. An equation which governs the transport velocity of the heap is presented.Comment: 9 pages, 5 figures, submitted to PR

Teaching Honors Cross-Divisional & Active-Learning Courses: Terrorism & Torture from a Global Perspective

How do we engage undergraduate students in intercultural awareness and global citizenship? One way is to better prepare them for a service-oriented, complex, multi-lingual, and globally focused workplace. Our panel will present how a public university with a metropolitan mission encourages interdisciplinary, cross-divisional, and co-taught courses where French and criminal justice professors collaborate for a global education cause

The electroretinographic diagnosis of the incomplete form of congenital stationary night blindness

AbstractFifteen patients with the incomplete form of congenital stationary night blindness (iCSNB) were reviewed to better characterize their electroretinographic (ERG) findings in view of differential diagnosis with other retinal conditions also presenting with negative bright-flash ERG responses. In all 15 patients, in dark-adapted conditions, the bright-flash ERG response had a normal a-wave followed by a subnormal b-wave. Oscillatory potentials (OPs) observed on the ascending limb of the b-wave, although delayed in implicit time, were of large amplitude. The response to a long-wavelength stimulus showed cone-related components and some well-delineated OPs. On the other hand, the photopically elicited cone responses were strongly abnormal, with a subnormal a-wave followed by a barely recordable b-wave. No OPs could be elicited under photopic conditions. The cone related components and the OP characteristics clearly distinguish iCSNB from the complete form of CSNB and other retinal conditions presenting with minimal fundus abnormalities but with negative bright-flash ERG responses, such as found in Duchenne muscular dystrophy and Åland Island eye disease. The severely abnormal post-synaptic components in the photopic recordings contrast with the well-differentiated cone activity evoked in scotopic conditions. We propose a cone system that does not respond optimally under the normal operating range (photopic) but rather under mesopic or scotopic conditions. In spite of the severe cone-ERG deficits, visual acuity was only slightly reduced. We propose that the defect, which interferes marginally with the neuronal flow of information, lies in the structures responsible for the building of the b-wave