Variational Perturbation Theory for Markov Processes

We develop a convergent variational perturbation theory for conditional probability densities of Markov processes. The power of the theory is illustrated by applying it to the diffusion of a particle in an anharmonic potential.Comment: Author Information under http://www.physik.fu-berlin.de/~kleinert/institution.html Latest update of paper also at http://www.physik.fu-berlin.de/~kleinert/33

Strong-Coupling Calculation of Fluctuation Pressure of a Membrane Between Walls

We calculate analytically the proportionality constant in the pressure law of a membrane between parallel walls from the strong-coupling limit of variational perturbation theory up to third order. Extrapolating the zeroth to third approximations to infinity yields the pressure constant alpha=0.0797149. This result lies well within the error bounds of the most accurate available Monte-Carlo result 0.0798 +- 0.0003.Comment: Author Information under http://www.physik.fu-berlin.de/~kleinert/institution.html . Latest update of paper also at http://www.physik.fu-berlin.de/~kleinert/28

Uncertainties for Pre- and Post-Launch Radiometric Calibration of Imaging Spectrometers for Multi-Sensor Applications

An important aspect to using imaging spectrometer data is the radiometric characterization and calibration of the sensors and validation of their data products and doing so with error budgets with known traceability. The radiometric accuracy of a given sensor is important for demonstrating the expected quality of data from the sensor. Known traceability allows data from multiple sensors to be directly comparable as will become more important in the near future with the expected launches of multiple imaging spectrometers from multiple countries, agencies, and commercial entities. The current work describes the state of pre- and post-launch radiometric absolute and relative uncertainties and their role in harmonising on-orbit data. Examples of prelaunch uncertainties based on the calibration of EnMAP and the calibration planned for the CLARREO Pathfinder Mission are presented highlighting recent work in the area of detector-based approaches using tunable laser sources. Post-launch calibration approaches for Pathfinder, EnMAP, CHIME, and DESIS including traditional vicarious calibration methods and the challenges of working with commercial data are presented. The vicarious calibration discussion relies on the example of the recently-available RadCalNet data to describe typical methods and challenges that will be faced when harmonising data between imaging spectrometers as well as with multispectral sensors

Just war and military morale: a brief reflection on the correlation between the legality of war and the moral repercussions for members of US and UK forces arising from the questionable legality of the campaign Iraqi Freedom of March 2003

Does it matter to a member of the military whether the military campaign in which he is taking part is lawful or not? Despite the observation that the crime of aggression (post Kampala 2010) constitutes a ‘leadership crime par excellence,’ which limits any (future) criminal responsibility accordingly, the legality or illegality of any military action under international law can create moral implications for the common foot soldier and mid-level officer and also have a tangible impact on the national legal frameworks under which these forces operate. This short article uses the example of Operation Iraqi Freedom (2003) to discuss the repercussions of a—most likely—illegal military campaign for individual members of democratic armed forces before the background of the present discussion of NATO led action in Libya

Conformational Mechanics of Polymer Adsorption Transitions at Attractive Substrates

Conformational phases of a semiflexible off-lattice homopolymer model near an attractive substrate are investigated by means of multicanonical computer simulations. In our polymer-substrate model, nonbonded pairs of monomers as well as monomers and the substrate interact via attractive van der Waals forces. To characterize conformational phases of this hybrid system, we analyze thermal fluctuations of energetic and structural quantities, as well as adequate docking parameters. Introducing a solvent parameter related to the strength of the surface attraction, we construct and discuss the solubility-temperature phase diagram. Apart from the main phases of adsorbed and desorbed conformations, we identify several other phase transitions such as the freezing transition between energy-dominated crystalline low-temperature structures and globular entropy-dominated conformations.Comment: 13 pages, 15 figure

The Island Earth Field Studio: A High School Summer Program on Polynesian Voyaging in Hawaii

The Island Earth Field Studio is a ten-day program for high school students to learn about Polynesian voyaging in Hawaii as a framework to understand non-Western knowledge systems. The program design is grounded in research on the historical significance of voyaging and informed by current literature on adolescent development and place-based pedagogy. To further refine the program, a needs assessment was conducted using a combination of surveys and interviews with parents and educators in the continental United States (mainland) as well as interviews with local partners in Hawaii. The assessment revealed that cultural learning and community building were viewed by potential mainland participants as the most beneficial elements of the program, and the focus on Polynesian voyaging made it stand out as a unique experience. Correspondingly, Hawaiian ground partners viewed the program as a worthy opportunity to share their mission of cultural and environmental sustainability. Based on recommendations from the needs assessment, the program will recruit a diverse cohort of students with strong interest in indigenous culture and sustainability. The travel program will begin on the island of Oahu, where students will get to know the natural environment, history, and cultural context of Hawaii. Then on Maui, a specific hands-on focus on voyaging integrated with exposure to a wider variety of Hawaiian community initiatives will lend both depth and breadth to students’ insights. As students gain knowledge and skills throughout the program, they will work together to develop ideas about how to use what they’ve learned to build stronger and more sustainable communities. This program design is intended to align with the mission of local partners while also allowing space for students to process their own growth as individuals and as a community of peers

Empirical Modeling of Used Nuclear Fuel Radiation Emissions for Safeguards Purposes

For nuclear nonproliferation safeguards, the ability to characterize used nuclear fuel (UNF) is a vital process. Fuel characterization allows for independent verification by inspectors of operator declarations of the special nuclear material flow and nuclear related activities within a facility, and an estimation of fissile material remaining in a fuel assembly. Current methods to verify this information rely heavily on non-destructive assay techniques, such as gamma spectroscopy and neutron detection measurements. While these measurements are effective tools for estimating a specific characteristic of the fuel, such as burnup or cooling time, they often require an accurate estimation of a select few isotopes in the fuel. This requirement means that the characterization is based on a very small amount of information that is contained in radiation emissions. To help overcome this limitation, this work investigates the use of empirical modeling to predict the burnup, initial enrichment, and cooling time of a Westinghouse 17x17 UNF assembly. This technique utilizes the entire spectrum of gamma emissions and gross neutron counts to predict each output to explore the full suite of information contained in these signatures. Three primary parametric modeling techniques are investigated for their performance in modeling this system: Ordinary Least Squares Regression (OLS), Principal Component Regression (PCR), and Partial Least Squares Regression (PLS). The models created are evaluated based on their root mean square percent error and condition number. The uncertainty of the best performing model is then quantified to understand the prediction interval of the predicted characterization and how this compares to the uncertainty of current measurement and characterization techniques. The PLS models are able to provide the best predictions while being stable. The PCR models have a consistent trade-off between accurate prediction results and stability. The OLS model provides fairly accurate results but is highly unstable due to correlations in the input data. The best model is the PLS model based on cross validation because it is stable, yields the lowest RMSPE values for burnup and enrichment predictions, and yields the second lowest percent of cooling time predictions that are more than 1 year away from the actual value. When used with the validation data set, this model yields RMSPE values of 0.42%, 1.39% and 4.61% for the burnup, enrichment, and cooling time, respectively. The total uncertainty of the predictions of this model are calculated to be 0.220 GWd/MTU, 0.051% U-235, and 0.694 years, for the burnup, enrichment, and cooling time, respectively

Development of a triple GEM UV-photon detector operated in pure CF4 for the PHENIX experiment

Results obtained with a triple GEM detector operated in pure CF4 with and without a reflective CsI photocathode are presented. The detector operates in a stable mode at gains up to 10^4. A deviation from exponential growth starts to develop when the total charge exceeds ~ 4 10^6 e leading to gain saturation when the total charge is ~ 2 10^7 e and making the structure relatively robust against discharges. No aging effects are observed in the GEM foils after a total accumulated charge of ~ 10 mC/cm^2 at the anode. The ion back-flow current to the reflective photocathode is comparable to the electron current to the anode. However, no significant degradation of the CsI photocathode is observed for a total ion back-flow charge of ~ 7 mC/cm^2.Comment: 14 pages, 11 figures, Submitted to NIM