A L\'evy input fluid queue with input and workload regulation

We consider a queuing model with the workload evolving between consecutive i.i.d.\ exponential timers $\{e_q^{(i)}\}_{i=1,2,...}$ according to a spectrally positive L\'evy process $Y_i(t)$ that is reflected at zero, and where the environment $i$ equals 0 or 1. When the exponential clock $e_q^{(i)}$ ends, the workload, as well as the L\'evy input process, are modified; this modification may depend on the current value of the workload, the maximum and the minimum workload observed during the previous cycle, and the environment $i$ of the L\'evy input process itself during the previous cycle. We analyse the steady-state workload distribution for this model. The main theme of the analysis is the systematic application of non-trivial functionals, derived within the framework of fluctuation theory of L\'evy processes, to workload and queuing models

Focusing on the Fixed Point of 4D Simplicial Gravity

Our earlier renormalization group analysis of simplicial gravity is extended. A high statistics study of the volume and coupling constant dependence of the cumulants of the node distribution is carried out. It appears that the phase transition of the theory is of first order, contrary to what is generally believed.Comment: Latex, 20 pages, 6 postscript figures, published versio

Describing psychological and behavioural problems in Omani young people: reliability of the Self-reported Strength and Difficulties Questionnaire (SDQ) in Oman

Aim: The aim of this study is to assess the reliability of the Strength and Difficulties Questionnaire (SDQ), including the impact subscale, when completed by school-age children in Oman. The SDQ is an essential tool for screening psychological and behavioural problems in school children but has only been partially tested in an Omani sample. Method: A cross sectional study. Children aged 11-16 from one private and four public schools in two areas of Oman (Muscat; Buraimi) completed the SDQ. Cronbachs alpha and person-product correlations were used to assess internal, and test-re-rest reliability. Results: 377/422 children completed the SDQ, 138 completed the re-test. The Total Difficulties (T-SDQ) score was normally distributed with 78% scoring normal, 13% borderline and 9% clinical significant scores. Girls’ scores were significantly higher than boys in T-SDQ and in emotional and prosocial subscales. Internal reliability for the T-SDQ was (Cronbach alpha = 0.72; Person Product-moment coefficient r=0.71; P<0.001), the impact subscale = 0.68 and varied between 0.26 and 0.60 for the subscales. Conclusion: The self-reported SDQ using T-SDQ score is a reliable screening tool for psychological and behavioural problems for Omani children. The T-SDQ can be disseminated within private and public-school systems. Having a reliable screening tool for identifying children with psychological and behavioural problems is a significant step to improving mental health pathways of care and outcomes in Oman

Patients' confidence in treatment decisions for early stage non-small cell lung cancer (NSCLC).

BACKGROUND: In early-stage Non-Small Cell Lung Cancer (NSCLC) patients, little is known about how to measure patient participation in Shared-Decision Making (SDM). We examined the psychometric properties and clinical acceptability of the Decision Self-Efficacy scale (DSE) in a cohort of patients undergoing to Stereotactic Ablative Radiotherapy (SABR) or Video-assisted Thoracoscopic Surgery (VATS) to capture patient involvement in treatment decisions. METHODS: In the context of a prospective longitudinal study (Life after Lung Cancer-LiLAC) involving 244 patients with early-stage NSCLC, 158 (64.7%) patients completed the DSE either on paper or electronically online prior to treatment with SABR or VATS pulmonary resection. DSE psychometric properties were examined using: principal components analysis of item properties and internal structure, and internal construct validity; we also performed a sensitivity analysis according to Eastern Cooperative Oncology Group Performance Status (ECOG PS), gender, age and treatment received (VATS or SABR) difference. RESULTS: Exploratory factor analysis using polychoric correlations substantiated that the 11 item DSE is one scale accounting for 81% of the variance. We calculated a value of 0.96 for Cronbach's alpha for the total DSE score. DSE scores did not differ by gender (p = 0.37), between the two treatment groups (p = 0.09) and between younger and older patients (p = 0.4). However, patients with an ECOG PS > 1 have a DSE mean of 73.8 (SD 26) compared to patients with a PS 0-1 who have a DSE mean of 85.8 (SD 20.3 p = 0.002). CONCLUSION: Findings provide preliminary evidence for the reliability and validity of the DSE questionnaire in this population. However, future studies are warranted to identify the most appropriate SDM tool for clinical practice in the lung cancer treatment field

Detection of the 5p-4f orbital crossing and its optical clock transition in Pr9+

Recent theoretical works have proposed atomic clocks based on narrow optical transitions in highly charged ions. The most interesting candidates for searches of new physics are those which occur at rare orbital crossings where the shell structure of the periodic table is reordered. There are only three such crossings expected to be accessible in highly charged ions, and hitherto none have been observed as both experiment and theory have proven difficult. In this work we observe an orbital crossing in highly charged ions for the first time, in a system chosen to be tractable from both sides: Pr9+. We present electron beam ion trap measurements of its spectra, including the inter-configuration lines that reveal the sought-after crossing. The proposed nHz-wide clock line, found to be at 452.334(1) nm, proceeds through hyperfine admixture of its upper state with an E2-decaying level. With state-of-the-art calculations we show that it has a very high sensitivity to new physics and extremely low sensitivity to external perturbations, making it a unique candidate for proposed precision studies

Stringent test of QED with hydrogenlike tin

Inner-shell electrons naturally sense the electric field close to the nucleus, which can reach extreme values beyond $10^{15}\,\text{V}/\text{cm}$ for the innermost electrons. Especially in few-electron highly charged ions, the interaction with the electromagnetic fields can be accurately calculated within quantum electrodynamics (QED), rendering these ions good candidates to test the validity of QED in strong fields. Consequently, their Lamb shifts were intensively studied in the last decades. Another approach is the measurement of $g$ factors in highly charged ions. However, so far, either experimental accuracy or small field strength in low-$Z$ ions limited the stringency of these QED tests. Here, we report on our high-precision, high-field test of QED in hydrogenlike $^{118}$Sn$^{49+}$. The highly charged ions were produced with the Heidelberg-EBIT (electron beam ion trap) and injected into the ALPHATRAP Penning-trap setup, where the bound-electron $g$ factor was measured with a precision of 0.5 parts-per-billion. For comparison, we present state-of-the-art theory calculations, which together test the underlying QED to about $0.012\,\%$, yielding a stringent test in the strong-field regime. With this measurement, we challenge the best tests via the Lamb shift and, with anticipated advances in the $g$-factor theory, surpass them by more than an order of magnitude