Snowmelt simulations to determine the source of nutrients in snowmelt runoff

Non-Peer ReviewedAgriculture has been identified as a contributor of nutrients to surface waters. However, most sources of agricultural nutrients are diffuse and have not been clearly identified. A potential source that has been largely overlooked is nutrient release from senesced plant material. The release of nutrients from plant material during snowmelt and the subsequent transport of these nutrients in surface runoff could contribute to the eutrophication of downstream receiving waters. A snowmelt simulation study was designed to assess nutrient release from different plant residues during snowmelt in controlled conditions. Frozen residues were covered with a layer of snow that was typical of over-winter snow-cover and subjected to a number of thaw-freeze cycles. The resulting melt-water was analyzed for dissolved N, P and C content to assess the nutrient release potential of each residue. A range of plant residues, including cereals, pulse crops, oilseeds and native vegetation, were collected for testing. In addition, paired samples of residue and surface soil were collected and nutrient release during simulated snowmelt was measured for the soils and residues alone and in combination. The potential for residues to contribute nutrients to snowmelt was comparable to that for soils and varied with the nutrient content and freshness of the residue. Some interesting interactions between soils and residues were observed in the combined experiment. These results are particularly relevant to the development of beneficial agricultural management practices for the protection of water quality

Pesticide monitoring in inshore waters of the Great Barrier Reef using both time-integrated and event monitoring techniques (2013-2014)

The report details pesticide monitoring activities carried out utilising a combination of passive sampling and grab sampling techniques in the Great Barrier Reef Marine Park as part of the Reef Rescue Marine Monitoring Program (MMP). The MMP was implemented to evaluate changes in water quality in the Great Barrier Reef (GBR) and the status of key ecosystems under the Reef Water Quality Protection Plan (RWQPP) 2003 (which was further updated in 2009)

Pesticide monitoring in inshore waters of the Great Barrier Reef using both time-integrated and event monitoring techniques (2012-2013)

The report details pesticide monitoring activities carried out utilising a combination of passive sampling and grab sampling techniques in the Great Barrier Reef Marine Park as part of the Reef Rescue Marine Monitoring Program (MMP). The MMP was implemented to evaluate changes in water quality in the Great Barrier Reef (GBR) and the status of key ecosystems under the Reef Water Quality Protection Plan (RWQPP) 2003 (which was further updated in 2009).Report prepared by monitoring provider contractor to GBRMPA. Contract with gives GBRMPA complete use and distribution rights to all contract outputs, including this report

Marine Monitoring Program: Annual report for inshore pesticide monitoring 2014-2015

[Extract] Declining water quality influenced by land-based activities and run-off has been identified as a significant threat to the health and resilience of the Great Barrier Reef (the Reef). Sediment, nutrients and pesticides remain the key water quality issues and may have negative impacts on marine plants and animals (primarily corals and seagrass) that are exposed to run-off plumes in inshore marine areas. The Reef Water Quality Protection Plan (Reef Plan) is a collaborative program designed to improve the quality of water in the Reef though improved land management practises. In 2014-2015, Entox carried out water quality monitoring activities in the Great Barrier Reef Marine Park (the Marine Park) as part of the Marine Monitoring Program (MMP) under Reef Plan. The key objectives of the project are to monitor and assess trends in inshore water quality (i.e. concentrations of pesticides/ herbicides) against the Marine Park Water Quality Guidelines, and link inshore concentrations and their transport with end-of-catchment loads

Lithologic Controls on Focused Erosion and Intraplate Earthquakes in the Eastern Tennessee Seismic Zone

We present a new geomorphic model for the intraplate eastern Tennessee seismic zone (ETSZ). Previous studies document that the Upper Tennessee drainage basin is in a transient state of adjustment to ~150 m of base level fall that occurred in the Late Miocene. Using quantitative geomorphology, we demonstrate that base level fall resulted in the erosion of ~3,500 km3 of highly erodibility rock in an ~70 km wide by ~350‐km‐long corridor in the Paleozoic fold‐thrust belt above the ETSZ. Models of modern incision rates show a NE‐SW trending swath of elevated erosion ~30 km southeast of the center of the ETSZ. Stress modeling shows that lithologically focused erosion has affected fault clamping stress on preexisting, favorably oriented faults. We argue that the lithologically controlled transient erosional response to base level fall in the Upper Tennessee basin has given rise to and is sustaining earthquake activity in the ETSZ

Medical degree apprenticeships: a useful model for the future?

There has been much in the news about the possibility of an alternative route into medicine using medical apprenticeships. In this piece, the authors share their thoughts on the feasibility of apprenticeships, how such a system could be managed and the practicalities that would need to be addressed

Vesicle formation induced by thermal fluctuations

The process of fission and vesicle formation depends on the geometry of the membrane that will split. For instance, a flat surface finds it difficult to form vesicles because of the lack of curved regions where to start the process. Here we show that vesicle formation can be promoted by temperature, by using a membrane phase field model with Gaussian curvature. We find a phase transition between fluctuating and vesiculation phases that depends on temperature, spontaneous curvature, and the ratio between bending and Gaussian moduli. We analysed the energy dynamical behaviour of these processes and found that the main driving ingredient is the Gaussian energy term, although the curvature energy term usually helps with the process as well. We also found that the chemical potential can be used to investigate the temperature of the system. Finally we address how temperature changes the condition for spontaneous vesiculation for all geometries, making it happen in a wider range of values of the Gaussian modulus.Comment: 31 pages, 10 figure

Influence of goals on modular brain network organization during working memory

IntroductionTop-down control underlies our ability to attend relevant stimuli while ignoring irrelevant, distracting stimuli and is a critical process for prioritizing information in working memory (WM). Prior work has demonstrated that top-down biasing signals modulate sensory-selective cortical areas during WM, and that the large-scale organization of the brain reconfigures due to WM demands alone; however, it is not yet understood how brain networks reconfigure between the processing of relevant versus irrelevant information in the service of WM.MethodsHere, we investigated the effects of task goals on brain network organization while participants performed a WM task that required participants to detect repetitions (e.g., 0-back or 1-back) and had varying levels of visual interference (e.g., distracting, irrelevant stimuli). We quantified changes in network modularity–a measure of brain sub-network segregation–that occurred depending on overall WM task difficulty as well as trial-level task goals for each stimulus during the task conditions (e.g., relevant or irrelevant).ResultsFirst, we replicated prior work and found that whole-brain modularity was lower during the more demanding WM task conditions compared to a baseline condition. Further, during the WM conditions with varying task goals, brain modularity was selectively lower during goal-directed processing of task-relevant stimuli to be remembered for WM performance compared to processing of distracting, irrelevant stimuli. Follow-up analyses indicated that this effect of task goals was most pronounced in default mode and visual sub-networks. Finally, we examined the behavioral relevance of these changes in modularity and found that individuals with lower modularity for relevant trials had faster WM task performance.DiscussionThese results suggest that brain networks can dynamically reconfigure to adopt a more integrated organization with greater communication between sub-networks that supports the goal-directed processing of relevant information and guides WM