Assignment of dynamic transmission range based on estimation of vehicle density

Vehicular Ad Hoc Networks (VANET) have several characteristics that distinguish them from other ad hoc networks. Among those is the rapid change in topology due to traffic jams, which also disturbs the homogenous distribution of vehicles on the road. For this reason, a dynamic transmission range is more effective in maintaining connectivity while minimizing the adverse effects of a high transmission power. We provide a relationship that allows vehicles to estimate the local density and distinguish between two phases of traffic, freeflow and congested traffic. The density estimate is used to develop an algorithm that sets a vehicle transmission range dynamically according to local traffic conditions. Simulations of various road configurations show that the algorithm is successful in maintaining connectivity in highly dynamic networks

The role of the sea-surface temperature distribution on numerically simulated cyclogenesis during ERICA

The goal was to quantify the extent to which a sea surface temperature (SST) front can influence cyclogenesis. The approach was to use the Drexel Limited-Area Mesoscale Prediction System (LAMPS) dynamical model to simulate cyclogenesis over various SST fields. Research during the past year focused on the development and testing of a four dimensional data assimilation (FDDA) technique within LAMPS. The technique is a continuous dynamical assimilation where forcing terms are added to the governing model equations to gradually nudge the model solution toward a gridded analysis. Here, the nudging is used as a dynamic initialization tool during a 12 hour preforecast to generate model balanced initial conditions for a subsequent 24 hour numerical prediction. Tests were performed to determine which variables to nudge and how to specify the four dimensional weighting function used to scale the nudging terms. To date, optimal results were obtained by nudging the u and v components of the wind along with the potential temperature. The weighting function ranged from 0 to 1 and varies in time as a quadratic polynomial. It was initialized at 0, reached its maximum at 9 hours into the preforecast, and fell back at 0 to 12 hours. The nudging terms are included in the model equations for all grid points except those within the model predicted oceanic boundary layer. This design attempts to confine changes imposed by the specified SST field to the oceanic boundary layer during the preforecast period

Evaluation with Simulation of Lucerne-Based Cropping Systems to Combat Dryland Salinity in Australia

Dryland salinity is one of the most significant forms of land degradation that farmers face in Australia. There are currently 2.5 million ha affected by dryland salinity in Australia, and this may rise to 15 million ha over the next 30 to 100 years if no action is taken. National field experiments suggest that adoption of cropping systems that integrate deep-rooted perennials, such as lucerne, are important to reduce dryland salinity. This paper reports simulation results with APSIM (The Agricultural Production Systems Simulator), that have been used to explore climate, soil and agronomic factors affecting effectiveness of lucerne-based phase and companion cropping systems in sustaining crop yield and reducing deep-water drainage in South Australia

Influence of 100% and 40% oxygen on penumbral blood flow, oxygen level, and T2*-weighted MRI in a rat stroke model

Accurate imaging of the ischemic penumbra is a prerequisite for acute clinical stroke research. T2* magnetic resonance imaging (MRI) combined with an oxygen challenge (OC) is being developed to detect penumbra based on changes in blood deoxyhemoglobin. However, inducing OC with 100% O2 induces sinus artefacts on human scans and influences cerebral blood flow (CBF), which can affect T2* signal. Therefore, we investigated replacing 100% O2 OC with 40% O2 OC (5 minutes 40% O2 versus 100% O2) and determined the effects on blood pressure (BP), CBF, tissue pO2, and T2* signal change in presumed penumbra in a rat stroke model. Probes implanted into penumbra and contralateral cortex simultaneously recorded pO2 and CBF during 40% O2 (n=6) or 100% O2 (n=8) OC. In a separate MRI study, T2* signal change to 40% O2 (n=6) and 100% O2 (n=5) OC was compared. Oxygen challenge (40% and 100% O2) increased BP by 8.2% and 18.1%, penumbra CBF by 5% and 15%, and penumbra pO2 levels by 80% and 144%, respectively. T2* signal significantly increased by 4.56%±1.61% and 8.65%±3.66% in penumbra compared with 2.98%±1.56% and 2.79%±0.66% in contralateral cortex and 1.09%±0.82% and −0.32%±0.67% in ischemic core, respectively. For diagnostic imaging, 40% O2 OC could provide sufficient T2* signal change to detect penumbra with limited influence in BP and CBF

Influence of season and method of topkill on resprouting characteristics and biomass of Quercus nigra saplings from a southeastern U.S. pine-grassland ecosystem

© 2014, Springer Science+Business Media Dordrecht. The resprouting ability of woody plants in frequently burned ecosystems may be influenced by the season and method of topkill. We conducted an experiment to test for the effects of season and method of topkill on aboveground biomass, belowground biomass, and mortality of hardwoods found in a southeastern U.S. pine-grassland. We predicted that topkill occurring during the growing season and topkill by fire would have greater negative impacts on resprouting and root growth and result in greater mortality. We conducted a shadehouse experiment in north Florida in which we applied topkill treatments (burn, clip, and no-topkill) in three seasons (dormant, early growing, and mid growing) to Quercus nigra (water oak) saplings. Plants were destructively sampled 12 months post-treatment to measure aboveground and belowground biomass. Saplings topkilled in the early and mid growing seasons had reduced growth and greater mortality one-year post-treatment compared to plants topkilled in the dormant season. While there was no difference in one-year post-treatment biomass or mortality of saplings between the two methods of topkill, clipped plants had more stems and shorter average stem height than plants topkilled by fire. Root growth continued despite topkilling for all seasons and was greatest for no-topkill plants. These results suggest that while topkill reduces biomass, hardwoods have evolved to maintain belowground biomass reserves, enabling genets to resprout following subsequent topkilling and to persist through frequent disturbances

Results from the third Scottish National Prevalence Survey: is a population health approach now needed to prevent healthcare-associated infections?

Summary Background Healthcare associated infections (HAI) are a major public health concern and a significant cause of morbidity and mortality. A robust and current evidence base that is specific to local, national and Europe-wide settings is necessary to inform the development of strategies to reduce HAI and contain antimicrobial resistance (AMR). Aim To measure the prevalence of HAI and antimicrobial prescribing and identify key priority areas for interventions to reduce the burden of infection. Methods A national rolling PPS in National Health Service (NHS) acute, NHS non-acute, NHS paediatric and independent hospitals was carried out between September and November 2016 using the European Centre for Disease Prevention and Control protocol designed for the European PPS. Findings The prevalence of HAI was 4.6%, 2.7% and 3.2% in acute adults, paediatric and non-acute patient groups, respectively. The most common HAI types reported in adult patients were urinary tract infection and pneumonia. The prevalence of antimicrobial prescribing was 35.7%, 29.3% and 13.8% in acute adults, paediatric and non-acute patient groups, respectively. Respiratory, skin and soft tissue, gastrointestinal and urinary tract infections were the most common infections being treated at the time of survey. Conclusion HAI continues to be a public health concern in Scotland. UTI and pneumonia continue to place a significant burden on patients and on healthcare delivery, including those that develop in the community and require hospital admission. A broader population health approach which focuses on reducing the risk of infection upstream would reduce these infections in both community and hospital settings

Oscillation of high-altitude balloons

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/76907/1/AIAA-46071-816.pd