General description of electromagnetic radiation processes based on instantaneous charge acceleration in `endpoints'

We present a new methodology for calculating the electromagnetic radiation from accelerated charged particles. Our formulation --- the `endpoint formulation' --- combines numerous results developed in the literature in relation to radiation arising from particle acceleration using a complete, and completely general, treatment. We do this by describing particle motion via a series of discrete, instantaneous acceleration events, or `endpoints', with each such event being treated as a source of emission. This method implicitly allows for particle creation/destruction, and is suited to direct numerical implementation in either the time- or frequency-domains. In this paper, we demonstrate the complete generality of our method for calculating the radiated field from charged particle acceleration, and show how it reduces to the classical named radiation processes such as synchrotron, Tamm's description of Vavilov-Cherenkov, and transition radiation under appropriate limits. Using this formulation, we are immediately able to answer outstanding questions regarding the phenomenology of radio emission from ultra-high-energy particle interactions in both the Earth's atmosphere and the Moon. In particular, our formulation makes it apparent that the dominant emission component of the Askaryan Effect (coherent radio-wave radiation from high-energy particle cascades in dense media) comes from coherent `bremsstrahlung' from particle acceleration, rather than coherent Vavilov-Cherenkov radiation.Comment: accepted by Phys. Rev. E, new title, some corrections in equations and references, figure styles updated to match journal policie

Identifying Facilitators and Barriers for a Successful Student Registered Nurse Anesthetist’s Clinical Experience

Student registered nurse anesthetists experience a wide variety of barriers and facilitators to their clinical education; often rotating through several clinical sites during their nurse anesthesia educational program (NAEP) tenure. Existing evidence suggests SRNAs must be proficient in seeking, accepting, and utilizing feedback from clinical preceptors (Algiraigri, 2014). Accepting constructive criticism may be challenging for SRNAs as they are highly skilled, competent nurses who are now entering rigorous NAEPs as novices. Reverting from preceptor to preceptee can be a difficult transition for SRNAs. This project aimed to identify barriers and facilitators to a successful SRNA clinical education through a literature review and survey data obtained from SRNAs across the United States. The literature review and survey results revealed a need for continuing education on adult learning theory and improved communication skills in the clinical realm

Tilted String Cosmologies

Global symmetries of the string effective action are employed to generate tilted, homogeneous Bianchi type VI_h string cosmologies from a previously known stiff perfect fluid solution to Einstein gravity. The dilaton field is not constant on the surfaces of homogeneity. The future asymptotic state of the models is interpreted as a plane wave and is itself an exact solution to the string equations of motion to all orders in the inverse string tension. An inhomogeneous generalization of the Bianchi type III model is also found.Comment: 9 pages, Standard Latex Source. To appear in Physics Letters B Minor change: Authors now alphabetically liste

The economic viability of biomass crops versus conventional agricultural systems and its potential impact on farm incomes in Ireland

Ireland is currently importing 90 percent of its energy. The burning of domestically produced nonrenewable peat provides 4.9 percent of Ireland’s total primary energy supply while renewable biomass crops currently account for only 1 percent of the domestically produced energy supply. The Irish government have set a target of 30% of peat (approximately 0.9 million tonnes) used for electricity generation to be replaced by renewable energy crops. This would be equivalent to approximately 0.6 million tonnes of biomass crops or approximately 45,000 hectares of biomass. Direct payments and subsidies accounted for over 100 percent of average family farm income on beef and sheep farms in 2006. Therefore there appears to be significant potential for Irish farmers to replace conventional agricultural enterprises with biomass crops. A probit model was built to identify the socio-economic characteristics of farmers who may be willing to adopt energy crop production. The results from this were used in the construction of a linear programming model to determine the optimal enterprise for each farmer at varying energy prices.Willow, Miscanthus, Co-firing, Net present value, Probit, Linear programming, Agricultural Finance, Institutional and Behavioral Economics, Resource /Energy Economics and Policy,

Multispectral imaging of organ viability during uterine transplantation surgery in rabbits and sheep

Uterine transplantation surgery (UTx) has been proposed as a treatment for permanent absolute uterine factor infertility (AUFI) in the case of the congenital absence or surgical removal of the uterus. Successful surgical attachment of the organ and its associated vasculature is essential for the organ’s reperfusion and long-term viability. Spectral imaging techniques have demonstrated the potential for the measurement of hemodynamics in medical applications. These involve the measurement of reflectance spectra by acquiring images of the tissue in different wavebands. Measures of tissue constituents at each pixel can then be extracted from these spectra through modeling of the light–tissue interaction. A multispectral imaging (MSI) laparoscope was used in sheep and rabbit UTx models to study short- and long-term changes in oxygen saturation following surgery. The whole organ was imaged in the donor and recipient animals in parallel with point measurements from a pulse oximeter. Imaging results confirmed the re-establishment of adequate perfusion in the transplanted organ after surgery. Cornual oxygenation trends measured with MSI are consistent with pulse oximeter readings, showing decreased StO2 immediately after anastomosis of the blood vessels. Long-term results show recovery of StO2 to preoperative levels