Intercropping Systems for Sustainable Agriculture

Increasing sustainability in agriculture is an imperative target for whole food and feed production and transformation chains [...

Online motion correction for diffusion-weighted segmented-EPI and FLASH imaging

This paper explores the application of online motion correction using navigator echoes to the segmented-EPI and FLASH techniques. In segmented EPI this has the advantage over post-acquisition correction that the position in k-space of each segment is no longer subject to arbitrary shifts caused by rotation. In diffusion-weighted FLASH it has the advantage that the full magnetisation can be utilised in comparison to other methods of eliminating the sensitivity to bulk motion, in which the sensitivity is halved. Healthy subjects were investigated on a 3 T whole-body system in which the hardware has been modified so that navigator echoes can be recorded on a personal computer which generates the necessary magnetic field gradient correction pulses and shifts in the Larmor frequency within 800 μs. ECG triggering was used to avoid the period of non-rigid-body brain motion. Two orthogonal navigator echoes were employed. For segmented EPI it was found essential to minimise the T2* weighting of the navigator echoes to about 10 ms to obtain reliable results. High quality images were obtained for both methods examined. Online motion correction brings direct benefits to both the diffusion-weighted segmented-EPI and FLASH techniques

Crown Radius and Diameter at Breast Height Relationships for Six Bottomland Hardwood Species

The relationship between a tree\u27s crown radius and diameter at breast height (DBH) has a variety of uses including forest competition studies, tree crown densities, spacing and stocking relationships, wildlife habitat suitability models, and tree volume estimations. Estimating DBH from mean crown radius (MCR) is of interest to natural resource managers because MCR can be estimated from high resolution digital imagery using remote sensing techniques. DBH is a common tree dimensional characteristic that is used to quantify tree and stand structure. This research presents MCR/DBH and DBH/MCR relationships for boxelder (Acer negundo L.), sweet pecan (Carya illinoensis (Wang) K.Koch), sugarberry (Celtis laevigata Willd.), green ash (Fraxinus pennsylvanica Marsh.), Nuttall oak (Quercus nuttallii Palmer), and American elm (Ulmus americana L.). The linear model, y =a+b * x, provided the best model fit with adjusted r values of 0.567 to 0.855 for the 6 species. Crown radius can be determined from digital imagery and then used to predict DBH

Assessing the Cost of Best Management Practices in Arkansas

A geographic information system (GIS) is a set of powerful, computer-based, analytical algorithms for solving spatial data problems. Recently, due to increases in memory size, computing speed, and programming advances, personal computers have been used in spatial analysis problems. This study reports the benefits of using a PC-based GIS system to solve a common, but complicated problem in forest management: assignment of harvesting areas with harvesting exclusion zones. Two stands each from the USDA Crossett Experimental Forest, the University of Arkansas Forest, and the Ouachita National Forest (total six) were analyzed to determine the changes due to following best management practices (BMPs) and by excluding sensitive areas from harvesting activity with stream-side management zones (SMZs). A onetime loss land, averaging seven percent of the forest land, was taken out of production due to the implementation of SMZs. Benefit cost ratios of harvestable timber value to harvesting cost decreased with the imposition of SMZs, but the judicious use of portable bridging to span SMZs at critical locations mitigated losses significantly

Accuracy Assessment of Recreational and Mapping Grade GPS Receivers

Since its development in the early 1970s, Global Positioning System (GPS) technology has become more accessible and affordable for consumers. GPS applications have become ubiquitous in society. With the increased use of GPS, the question of accuracy is of concern. This study assessed the accuracy of four Garmin recreational GPS receivers, eTrex® , eTrex Legend® , eTrex Vista® , GPSMAP® 76CS, and three Trimble® mapping GPS receivers JunoTM , GeoExplorer3TM and GeoXHTM. Thirty-three ground control points (GCPs) were established in three different landscapes using survey grade GPS (Trimble’s 4700) that were corrected using National Geodetic Survey’s Online Positioning User Service (OPUS). Eleven GCPs were established in a forest landscape, eleven near buildings to simulate an urban landscape, and eleven with a clear unobstructed sky. The GPS receivers were tested with the Wide Angle Augmentation System (WAAS) on and off. In addition, results from averaging 30 GPS positions were evaluated. This study showed the GeoXH was the most accurate receiver and that the accuracy of the recreational (Garmin) receivers was from 2.52 to 18.42 meters depending on the landscape. The accuracies of the Garmin GPS receivers were similar

Carrier transfer between confined and localized states in type II InAs/GaAsSb quantum wells

The work has been supported from iCspec project, which received funding from the European Commission’s Horizon 2020 Research and Innovation Programme under grant agreement No. 636930, and also by the National Science Centre of Poland within Grant No. 2014/15/B/ST7/04663.Temperature-resolved photoluminescence studies were performed on tensely-strained AlSb/InAs/GaAsSb W-shaped type II quantum wells. They revealed two emission bands: one at lower energy of localized origin resulting from carrier trapping states at interfaces and dominates at low-temperature; and one corresponding to the fundamental optical transition in the type II quantum well. With the temperature increase to 170—200 K the low-energy emission is quenched and the high-energy band dominates and its intensity increases, indicating carrier transfer processes between the respective states at elevated temperatures. In addition, the integrated photoluminescence intensity was measured as a function of excitation power. At high excitation regime the emission intensity of the low-energy emission band saturated, indicating low density of states, thus confirming its localized nature. The depth of the localization potential at the InAs/GaAsSb interface was determined to be 13—15 meV.Publisher PDFPeer reviewe

Assessing the Cost of Best Management Practices in Arkansas

A geographic information system (GIS) is a set of powerful, computer-based, analytical algorithms for solving spatial data problems. Recently, due to increases in memory size, computing speed, and programming advances, personal computers have been used in spatial analysis problems. This study reports the benefits of using a PC-based GIS system to solve a common, but complicated problem in forest management: assignment of harvesting areas with harvesting exclusion zones. Two stands each from the USDA Crossett Experimental Forest, the University of Arkansas Forest, and the Ouachita National Forest (total six) were analyzed to determine the changes due to following best management practices (BMPs) and by excluding sensitive areas from harvesting activity with stream-side management zones (SMZs). A onetime loss land, averaging seven percent of the forest land, was taken out of production due to the implementation of SMZs. Benefit cost ratios of harvestable timber value to harvesting cost decreased with the imposition of SMZs, but the judicious use of portable bridging to span SMZs at critical locations mitigated losses significantly

Impaired hemodynamics and neural activation? A fMRI study of major cerebral artery stenosis

Functional MRI motor mapping was performed in two women with unilateral high-grade stenosis of the middle cerebral artery (MCA) to determine the influence of impaired hemodynamics on the blood oxygenation level dependent (BOLD) response. In both patients no structural lesions were present in primary motor pathways. A redistribution of the motor network to the healthy hemisphere was the main indicator of chronic hemodynamic compromise

Optimizing the bioenergy water footprint by selecting SRC willow canopy phenotypes: regional scenario simulations

© The Author(s) 2019. Published by Oxford University Press on behalf of the Annals of Botany Company. All rights reserved. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted reuse, distribution, and reproduction in any medium, provided the original work is properly cited.Background and Aims: Bioenergy is central for the future energy mix to mitigate climate change impacts; however, its intricate link with the water cycle calls for an evaluation of the carbon–water nexus in biomass production. The great challenge is to optimize trade-offs between carbon harvest and water use by choosing cultivars that combine low water use with high productivity. Methods: Regional scenarios were simulated over a range of willow genotype × environment interactions for the major UK soil × climate variations with the process-based model LUCASS. Soil available water capacity (SAWC) ranged from 51 to 251 mm and weather represented the north-west (wet, cool), north-east (dry, cool), south-west (wet, warm) and south-east (dry, warm) of the UK. Scenario simulations were evaluated for small/open narrow-leaf (NL) versus large/closed broad-leaf (BL) willow canopy phenotypes using baseline (1965–89) and warmer recent (1990–2014) weather data. Key Results: The low productivity under baseline climate in the north could be compensated by choosing BL cultivars (e.g. ‘Endurance’). Recent warmer climate increased average productivity by 0.5–2.5 t ha−1, especially in the north. The modern NL cultivar ‘Resolution’ had the smallest and most efficient water use. On marginal soils (SAWC <100 mm), yields remained below an economic threshold of 9 t ha−1 more frequently under baseline than recent climate. In the drought-prone south-east, ‘Endurance’ yielded less than ‘Resolution’, which consumed on average 17 mm year−1 less water. Assuming a planting area of 10 000 ha, in droughty years between 1.3 and 4.5 × 106 m3 of water could be saved, with a small yield penalty, for ‘Resolution’. Conclusions: With an increase in air temperature and occasional water scarcities expected with climate change, high-yielding NL cultivars should be the preferred choice for sustainable use of marginal lands and reduced competition with agricultural food crops.Peer reviewedFinal Published versio

Monolithic single mode interband cascade lasers with wide wavelength tunability

Financial support by the European Union in terms of the WideLase project (grant agreement no: 318798) within the Seventh Framework Programme is gratefully acknowledged.Monolithic two-section interband cascade lasers offering a wide wavelength tunability in the wavelength range around 3.7 μm are presented. Stable single mode emission in several wavelength channels was realized using the concept of binary superimposed gratings and two-segment Vernier-tuning. The wavelength selective elements in the two segments were based on specially designed lateral metal grating structures defined by electron beam lithography. A dual-step dry etch process provided electrical separation between the segments. Individual current control of the segments allowed wavelength channel selection as well as continuous wavelength tuning within channels. A discontinuous tuning range extending over 158 nm in up to six discrete wavelength channels was achieved. Mode hop free wavelength tuning up to 14 nm was observed within one channel. The devices can be operated in continuous wave mode up to 30 °C with output powers of 3.5 mW around room temperature.PostprintPeer reviewe