First passage behaviour of fractional Brownian motion in two-dimensional wedge domains

We study the survival probability and the corresponding first passage time density of fractional Brownian motion confined to a two-dimensional open wedge domain with absorbing boundaries. By analytical arguments and numerical simulation we show that in the long time limit the first passage time density scales as t**{-1+pi*(2H-2)/(2*Theta)} in terms of the Hurst exponent H and the wedge angle Theta. We discuss this scaling behaviour in connection with the reaction kinetics of FBM particles in a one-dimensional domain.Comment: 6 pages, 4 figure

What is the Connection Between Issues, Bugs, and Enhancements? (Lessons Learned from 800+ Software Projects)

Agile teams juggle multiple tasks so professionals are often assigned to multiple projects, especially in service organizations that monitor and maintain a large suite of software for a large user base. If we could predict changes in project conditions changes, then managers could better adjust the staff allocated to those projects.This paper builds such a predictor using data from 832 open source and proprietary applications. Using a time series analysis of the last 4 months of issues, we can forecast how many bug reports and enhancement requests will be generated next month. The forecasts made in this way only require a frequency count of this issue reports (and do not require an historical record of bugs found in the project). That is, this kind of predictive model is very easy to deploy within a project. We hence strongly recommend this method for forecasting future issues, enhancements, and bugs in a project.Comment: Accepted to 2018 International Conference on Software Engineering, at the software engineering in practice track. 10 pages, 10 figure

Ethical difficulties in clinical practice : experiences of European doctors

Background: Ethics support services are growing in Europe to help doctors in dealing with ethical difficulties. Currently, insufficient attention has been focused on the experiences of doctors who have faced ethical difficulties in these countries to provide an evidence base for the development of these services. Methods: A survey instrument was adapted to explore the types of ethical dilemma faced by European doctors, how they ranked the difficulty of these dilemmas, their satisfaction with the resolution of a recent ethically difficult case and the types of help they would consider useful. The questionnaire was translated and given to general internists in Norway, Switzerland, Italy and the UK. Results: Survey respondents (n = 656, response rate 43%) ranged in age from 28 to 82 years, and averaged 25 years in practice. Only a minority (17.6%) reported having access to ethics consultation in individual cases. The ethical difficulties most often reported as being encountered were uncertain or impaired decisionmaking capacity (94.8%), disagreement among caregivers (81.2%) and limitation of treatment at the end of life (79.3%). The frequency of most ethical difficulties varied among countries, as did the type of issue considered most difficult. The types of help most often identified as potentially useful were professional reassurance about the decision being correct (47.5%), someone capable of providing specific advice (41.1%), help in weighing outcomes (36%) and clarification of the issues (35.9%). Few of the types of help expected to be useful varied among countries. Conclusion: Cultural differences may indeed influence how doctors perceive ethical difficulties. The type of help needed, however, did not vary markedly. The general structure of ethics support services would not have to be radically altered to suit cultural variations among the surveyed countries

X-Ray Irradiation Apparatus in Which an X-Ray Source is Energized Upon the Recording of Irradiation Dosage Data

Apparatus for use in examining or treating patients with X-radiation or the like requires the making of a permanent record of the radiation applied. The operation of the radiation source is controlled in dependence upon the making of the record and the to radiation, or dose exposure is limited to a predetermined amount. A method is disclosed for safeguarding the patient and for producing a tangible record of the dose to which the patient is subjected

Quantifying signals with power-law correlations: A comparative study of detrended fluctuation analysis and detrended moving average techniques

Detrended fluctuation analysis (DFA) and detrended moving average (DMA) are two scaling analysis methods designed to quantify correlations in noisy non-stationary signals. We systematically study the performance of different variants of the DMA method when applied to artificially generated long-range power-law correlated signals with an {\it a-priori} known scaling exponent $\alpha_{0}$ and compare them with the DFA method. We find that the scaling results obtained from different variants of the DMA method strongly depend on the type of the moving average filter. Further, we investigate the optimal scaling regime where the DFA and DMA methods accurately quantify the scaling exponent $\alpha_{0}$, and how this regime depends on the correlations in the signal. Finally, we develop a three-dimensional representation to determine how the stability of the scaling curves obtained from the DFA and DMA methods depends on the scale of analysis, the order of detrending, and the order of the moving average we use, as well as on the type of correlations in the signal.Comment: 15 pages, 16 figure

First recorded occurrence of detrital baddeleyite (ZrO2) in sedimentary rock (Smith Bank Formation, Triassic, Central North Sea)

Acknowledgements and Funding The authors wish to thank John Still of the University of Aberdeen for his invaluable assistance with the SEM-EDS analyses. This work was conducted as part of the Triassic Mudstones Joint Industry Project which was sponsored by BP, ConocoPhillips, EON E&P, Esso Exploration and Production UK Limited, GDF SUEZ E&P UK Ltd, JX Nippon, Maersk Oil, Shell and Total.Peer reviewedPostprin

Late-Time Optical and UV Spectra of SN 1979C and SN 1980K

A low-dispersion Keck I spectrum of SN 1980K taken in August 1995 (t = 14.8 yr after explosion) and a November 1997 MDM spectrum (t = 17.0 yr) show broad 5500 km s^{-1} emission lines of H\alpha, [O I] 6300,6364 A, and [O II] 7319,7330 A. Weaker but similarly broad lines detected include [Fe II] 7155 A, [S II] 4068,4072 A, and a blend of [Fe II] lines at 5050--5400 A. The presence of strong [S II] 4068,4072 A emission but a lack of [S II] 6716,6731 A emission suggests electron densities of 10^{5-6} cm^{-3}. From the 1997 spectra, we estimate an H\alpha flux of 1.3 \pm 0.2 \times 10^{-15} erg cm^{-2} s^{-1} indicating a 25% decline from 1987--1992 levels during the period 1994 to 1997, possibly related to a reported decrease in its nonthermal radio emission.Comment: 21 pages, 8 figures, submitted to the Astronomical Journa

Possibility between earthquake and explosion seismogram differentiation by discrete stochastic non-Markov processes and local Hurst exponent analysis

The basic purpose of the paper is to draw the attention of researchers to new possibilities of differentiation of similar signals having different nature. One of examples of such kind of signals is presented by seismograms containing recordings of earthquakes (EQ's) and technogenic explosions (TE's). We propose here a discrete stochastic model for possible solution of a problem of strong EQ's forecasting and differentiation of TE's from the weak EQ's. Theoretical analysis is performed by two independent methods: with the use of statistical theory of discrete non-Markov stochastic processes (Phys. Rev. E62,6178 (2000)) and the local Hurst exponent. Time recordings of seismic signals of the first four dynamic orthogonal collective variables, six various plane of phase portrait of four dimensional phase space of orthogonal variables and the local Hurst exponent have been calculated for the dynamic analysis of the earth states. The approaches, permitting to obtain an algorithm of strong EQ's forecasting and to differentiate TE's from weak EQ's, have been developed.Comment: REVTEX +12 ps and jpg figures. Accepted for publication in Phys. Rev. E, December 200