3,344 research outputs found
Two-fluid magnetic island dynamics in slab geometry: II - Islands interacting with resistive walls or static external resonant magnetic perturbations
The dynamics of a propagating magnetic island interacting with a resistive
wall or a static external magnetic perturbation is investigated using
two-fluid, drift-MHD theory in slab geometry. In both cases, the island
equation of motion is found to take exactly the same form as that predicted by
single-fluid MHD theory. Three separate ion polarization terms are found in the
Rutherford island width evolution equation. The first is the drift-MHD
polarization term for an isolated island, and is completely unaffected by
interaction with a wall or magnetic perturbation. Next, there is the
polarization term due to interaction with a wall or magnetic perturbation which
is predicted by single-fluid MHD theory. Finally, there is a hybrid of the
other two polarization terms. The sign of this term depends on many factors.
However, under normal conditions, it is stabilizing if the unperturbed island
propagates in the ion diamagnetic direction (in the lab. frame), and
destabilizing if it propagates in the electron diamagnetic direction
Support: Can it be a value creation strategy for positive marketing?
In pursuit of improving people's wellbeing and engaging in positive marketing, this paper addresses the application of Vickers' Appreciation System to deepen our understanding of how people comprehend their environment and respond to improve their situation. The paper highlights how companies can collaboratively engage in people's appreciation and support them in fulfilling their needs
Two-fluid magnetic island dynamics in slab geometry: I - Isolated islands
A set of reduced, 2-D, two-fluid, drift-MHD equations is derived. Using these
equations, a complete and fully self-consistent solution is obtained for an
isolated magnetic island propagating through a slab plasma with uniform but
different ion and electron fluid velocities. The ion and electron fluid flow
profiles around the island are uniquely determined, and are everywhere
continuous. Moreover, the island phase-velocity is uniquely specified by the
condition that there be zero net electromagnetic force acting on the island.
Finally, the ion polarization current correction to the Rutherford island width
evolution equation is evaluated, and found to be stabilizing provided that the
anomalous perpendicular ion viscosity significantly exceeds the anomalous
perpendicular electron viscosity
Examining Prehistoric Migration Patterns in the Palauan Archipelago: A Computer Simulated Analysis of Drift Voyaging
A number of recent genetic, linguistic, and archaeological studies have attempted to ascertain the origin of settlers to the Palauan archipelago, but it remains a complex and debated issue. To provide additional insight into colonization strategies and settlement patterns, we conducted computer simulations of drift voyages to the Palauan archipelago based on historically recorded winds and currents. Drift voyages were considered here as drifting before the wind when lost, a strategy documented for Pacific Islanders. The simulations suggest that peoples drifting before the wind from the southern Philippines would have had the most success in landfall. This finding supports the current hypothesis of human colonization to the islands of Palau. KEYWORDS: Computer simulation, drift voyaging, seafaring, colonization, Palau, Micronesia
Prehospital critical care is associated with increased survival in adult trauma patients in Scotland
Background Scotland has three prehospital critical care teams (PHCCTs) providing enhanced care support to a usually paramedic-delivered ambulance service. The effect of the PHCCTs on patient survival following trauma in Scotland is not currently known nationally. Methods National registry-based retrospective cohort study using 2011-2016 data from the Scottish Trauma Audit Group. 30-day mortality was compared between groups after multivariate analysis to account for confounding variables. Results Our data set comprised 17 157 patients, with a mean age of 54.7 years and 8206 (57.5%) of male gender. 2877 patients in the registry were excluded due to incomplete data on their level of prehospital care, leaving an eligible group of 14 280. 13 504 injured adults who received care from ambulance clinicians (paramedics or technicians) were compared with 776 whose care included input from a PHCCT. The median Injury Severity Score (ISS) across all eligible patients was 9; 3076 patients (21.5%) met the ISS>15 criterion for major trauma. Patients in the PHCCT cohort were statistically significantly (all p < 0.01) more likely to be male; be transported to a prospective Major Trauma Centre; have suffered major trauma; have suffered a severe head injury; be transported by air and be intubated prior to arrival in hospital. Following multivariate analysis, the OR for 30-day mortality for patients seen by a PHCCT was 0.56 (95% CI 0.36 to 0.86, p=0.01). Conclusion Prehospital care provided by a physician-led critical care team was associated with an increased chance of survival at 30 days when compared with care provided by ambulance clinicians
Postoperative complications associated with external skeletal fixators in cats
OBJECTIVES:
The objective of this study was to quantify complications associated with external skeletal fixators (ESFs) in cats and to identify potential risk factors.
METHODS:
A retrospective review of medical records and radiographs following ESF placement was performed.
RESULTS:
Case records of 140 cats were reviewed; fixator-associated complications (FACs) occurred in 19% of cats. The region of ESF placement was significantly associated with complication development. Complications developed most frequently in the femur (50%), tarsus (35%) and radius/ulna (33%). Superficial pin tract infection (SPTI) and implant failure accounted for 45% and 41% of all FACs, respectively. SPTI occurred more frequently in the femur, humerus and tibia, with implant failure more frequent in the tarsus. No association between breed, age, sex, weight, fracture type (open vs closed), ESF classification, number of pins per bone segment, degree of fracture load sharing, and the incidence or type of FAC was identified. No association between region of placement, breed, age, sex, weight, fracture type (open vs closed), ESF classification, number of pins per bone segment, fracture load sharing and the time to complication development was identified.
CONCLUSIONS AND RELEVANCE:
Complication development is not uncommon in cats following ESF placement. The higher complication rate in the femur, tarsus and radius/ulna should be considered when reviewing options for fracture management. However, cats appear to have a lower rate of pin tract infections than dogs
Effects of negative energy balance on liver gene and protein expression during the early postpartum period and its impacts on dairy cow fertility
End of project reportNegative energy balance (NEB) is a severe metabolic affecting high yielding dairy cows early post partum with both concurrent and latent negative effects on cow fertility as well as on milk production and cow health. The seasonal nature of Irish dairy production necessitates high cow fertility and a compact spring calving pattern in order to maximise grass utilisation. Poor dairy cow reproductive performance currently costs the Irish cattle industry in excess of €400 million annually. High milk yields have been associated with lower reproductive efficiency, and it has been suggested that this effect is probably mediated through its effects on the energy balance of the cow during lactation. The modern high genetic merit dairy cow prioritises nutrient supply towards milk production in early lactation and this demand takes precedence over the provision of optimal conditions for reproduction. In this study we used the bovine Affymetrix 23,000 gene microarray, which contains the most comprehensive set of bovine genes to be assembled and provides a means of investigating the modifying influences of energy balance on liver gene expression.
Cows in severe negative energy balance (SNEB) in early lactation showed altered hepatic gene expression in metabolic processes as well as a down regulation of the insulin-like growth factor (IGF) system, where insulin like growth factor-1 (IGF-1), growth hormone receptor variant 1A (GHR1A) and insulin-like growth factor binding protein-acid labile subunit (IGFBP-ALS) were down regulated compared to the cows in the moderate negative energy balance MNEB group, consistent with a five-fold reduction in systemic concentrations of IGF1 in the SNEB group.Cows in SNEB showed elevated expression of key genes involved in the inflammatory response such as interleukin-8 (IL-8). There was a down regulation of genes involved in cellular growth in SNEB cows and moreover a negative regulator of cellular proliferation (HGFIN) was up regulated in SNEB cows, which is likely to compromise adaptation and recovery from NEB.
The puma method of analysis revealed that 417 genes were differentially regulated by EB (P<0.05), of these genes 190 were up-regulated while 227 were down-regulated, with 405 genes having known biological functions. From Ingenuity Pathway Analysis (IPA), lipid catabolism was found to be the process most affected by differences in EB status
Randomisation before consent : avoiding delay to time-critical intervention and ensuring informed consent
Peer reviewe
Organic synthesis: march of the machines.
Organic synthesis is changing; in a world where budgets are constrained and the environmental impacts of practice are scrutinized, it is increasingly recognized that the efficient use of human resource is just as important as material use. New technologies and machines have found use as methods for transforming the way we work, addressing these issues encountered in research laboratories by enabling chemists to adopt a more holistic systems approach in their work. Modern developments in this area promote a multi-disciplinary approach and work is more efficient as a result. This Review focuses on the concepts, procedures and methods that have far-reaching implications in the chemistry world. Technologies have been grouped as topics of opportunity and their recent applications in innovative research laboratories are described.The authors gratefully acknowledge support from UK Engineering and Physical Sciences Research Council (SVL and RMM), Woolf Fisher Trust (DEF) and Pfizer Worldwide Research and Development (CB, RJI).This is the accepted manuscript. The final version is available at http://onlinelibrary.wiley.com/doi/10.1002/anie.201410744/abstract
Hydrologic and Hydraulic Modeling of the Tunnel and Reservoir Plan System in Northeastern Illinois
The Tunnel and Reservoir Plan (TARP) was adopted by the Metropolitan Sanitary District of Greater Chicago in 1972 to address combined sewer overflow (CSO) pollution and flooding problems in 970 km2 of the Chicago metropolitan area served by combined sewers. TARP consists of about 175 km of tunnels, three reservoirs, 256 drop shafts, and over 600 connecting structures, pumping stations, and other appurtenances for the capture and storage of CSOs and for conveying the stored CSOs to water reclamation plants for treatment. The TARP system is comprised of three independent systems: the Calumet system serving the south suburbs and a portion of the south side of Chicago, the Upper Des Plaines system serving the northwest suburbs, and the Mainstream/ Des Plaines system serving the remainder of Chicago and the north, west and southwest suburbs.
The Metropolitan Water Reclamation District of Greater Chicago (MWRDGC) desires to develop new, updated and enhanced computer models to allow for simulation of the TARP systems. The new models will be used to optimize operation of the system as actually constructed, to determine constraints in the system, identify physical changes that may be needed to improve performance, and allow what-if analyses to be performed for potential storm scenarios and facility revisions. The modeling includes development of a Physical Inventory system, Hydraulic Modeling of the TARP systems, and Hydrologic Modeling of the TARP service areas. The Physical Inventory provides a digital description of the physical geometry of the TARP system and the related hydraulic performance of system components. Hydrologic Modeling uses data for each dropshafts service area to determine hydrographs describing the inflows to the TARP systems. A ma jor component of the Hydrologic Modeling is to develop tools and methods that allow robust simulation of the extreme heterogeneity of highly urbanized systems and that provide guidance for data compilation needed to improve the accuracy of such simulations. Hydraulic Modeling uses the information from the Physical Inventory and the Hydrologic Modeling to simulate hydraulic response of the TARP system to different inputs. The Hydraulic Modeling tools developed are capable of simulating the range of possible flows in the system, from gravity flows over a dry bed to mixed gravity/surcharged flows to shocks and hydraulic transients
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