Core correlation effects in multiconfiguration calculations of isotope shifts in Mg I

The present work reports results from systematic multiconfiguration Dirac-Hartree-Fock calculations of isotope shifts for several well-known transitions in neutral magnesium. Relativistic normal and specific mass shift factors as well as the electronic probability density at the origin are calculated. Combining these electronic quantities with available nuclear data, energy and transition level shifts are determined for the $^{26}$Mg$-^{24}$Mg pair of isotopes. Different models for electron correlation are adopted. It is shown that although valence and core-valence models provide accurate values for the isotope shifts, the inclusion of core-core excitations in the computational strategy significantly improves the accuracy of the transition energies and normal mass shift factors.Comment: 2 figures, submitted to Physical Review

The effect of smoking on survival and bone loss of implants with a fluoride-modified surface: a 2-year retrospective analysis of 1106 implants placed in daily practice

Aim: To compare survival and peri-implant bone loss of implants with a fluoride-modified surface in smokers and nonsmokers. Materials and Methods: Patient files of all patients referred for implant treatment from November 2004 to 2007 were scrutinized. All implants were placed by the same experienced surgeon (BC). The only inclusion criterion was a follow-up time of at least 2 years. Implant survival and bone loss were assessed by an external calibrated examiner (SV) comparing digital peri-apical radiographs taken during recall visits with the post-operative ones. Implant success was determined according to the international success criteria (Albrektsson et al. 1986). Survival of implants installed in smokers and nonsmokers were compared using the log-rank test. Both non-parametric tests and fixed model analysis were adopted to evaluate bone loss in smokers and nonsmokers. Results: 1106 implants in 300 patients (186 females; 114 males) with a mean follow-up of 31 months (SD 7.15; range 24-58) were included. 19 implants in 17 patients failed, resulting in an overall survival rate of 98.3% on implant level and 94.6% on patient level. After a follow-up period of 2 years, the CSR was 96.7% and 99.1% with the patient and implant as statistical unit respectively. Implant survival was significantly higher for nonsmokers compared to smokers (implant level p = 0.025; patient level p = 0.017). The overall mean bone loss was 0.34 mm (n = 1076; SD 0.65; range 0.00-7.10). Smokers lost significantly more bone compared to nonsmokers in the maxilla (0.74 mm; SD 1.07 vs 0.33 mm; SD 0.65; p < 0.001), but not in the mandible (0.25mm; SD 0.65 vs 0.22mm; SD 0.50; p = 0.298). Conclusion: The present study is the first to compare peri-implant bone loss in smokers and nonsmokers from the time of implant insertion (baseline) to at least 2 years of follow-up. Implants with a fluoride-modified surface demonstrated a high survival rate and limited bone loss. However, smokers are at higher risk to experience implant failure and more prone to show peri-implant bone loss in the maxilla. Whether this bone loss is predicting future biological complications remains to be evaluated

Periodic Jacobi operator with finitely supported perturbations: the inverse resonance problem

We consider a periodic Jacobi operator $H$ with finitely supported perturbations on ${\Bbb Z}.$ We solve the inverse resonance problem: we prove that the mapping from finitely supported perturbations to the scattering data: the inverse of the transmission coefficient and the Jost function on the right half-axis, is one-to-one and onto. We consider the problem of reconstruction of the scattering data from all eigenvalues, resonances and the set of zeros of $R_-(\lambda)+1,$ where $R_-$ is the reflection coefficient

A Role-Based Approach for Orchestrating Emergent Configurations in the Internet of Things

The Internet of Things (IoT) is envisioned as a global network of connected things enabling ubiquitous machine-to-machine (M2M) communication. With estimations of billions of sensors and devices to be connected in the coming years, the IoT has been advocated as having a great potential to impact the way we live, but also how we work. However, the connectivity aspect in itself only accounts for the underlying M2M infrastructure. In order to properly support engineering IoT systems and applications, it is key to orchestrate heterogeneous 'things' in a seamless, adaptive and dynamic manner, such that the system can exhibit a goal-directed behaviour and take appropriate actions. Yet, this form of interaction between things needs to take a user-centric approach and by no means elude the users' requirements. To this end, contextualisation is an important feature of the system, allowing it to infer user activities and prompt the user with relevant information and interactions even in the absence of intentional commands. In this work we propose a role-based model for emergent configurations of connected systems as a means to model, manage, and reason about IoT systems including the user's interaction with them. We put a special focus on integrating the user perspective in order to guide the emergent configurations such that systems goals are aligned with the users' intentions. We discuss related scientific and technical challenges and provide several uses cases outlining the concept of emergent configurations.Comment: In Proceedings of the Second International Workshop on the Internet of Agents @AAMAS201

Breakdown of disordered media by surface loads

We model an interface layer connecting two parts of a solid body by N parallel elastic springs connecting two rigid blocks. We load the system by a shear force acting on the top side. The springs have equal stiffness but are ruptured randomly when the load reaches a critical value. For the considered system, we calculate the shear modulus, G, as a function of the order parameter, \phi, describing the state of damage, and also the ``spalled'' material (burst) size distribution. In particular, we evaluate the relation between the damage parameter and the applied force and explore the behaviour in the vicinity of material breakdown. Using this simple model for material breakdown, we show that damage, caused by applied shear forces, is analogous to a first-order phase transition. The scaling behaviour of G with \phi is explored analytically and numerically, close to \phi=0 and \phi=1 and in the vicinity of \phi_c, when the shear load is close but below the threshold force that causes material breakdown. Our model calculation represents a first approximation of a system subject to wear induced loads.Comment: 15 pages, 7 figure

Glancing at the Content of Substantive Rules Under the Jurisdiction-Selecting Approach

Antalet individer med funktionsnedsättning ökar, dels beroende på att numera kan sjukdomar botas som tidigare inte kunde botas och dels beroende på att allt fler för tidigt födda barn kan räddas. Den orala hälsan är ofta negativt påverkad hos personer med funktionsnedsättning och det föreligger risk att dessa personer, trots ett större tandvårdsbehov än andra, erhåller mindre tandvård. Anledningen till detta är inte helt känd. Syftet med våra studier var därför att fördjupa kunskapen om hur personer med funktionsnedsättning och deras anhöriga prioriterar och tänker om oral hälsa. Syftet med studierna var också att fördjupa kunskapen om hur hälso- och sjukvårdspersonal samt tandvårdspersonal tänker om behov avseende bemötande och oral hälsa hos personer med funktionsnedsättning. Den kvalitativa forskningsmetoden grounded theory har valts då den är speciellt lämplig på områden där teorier är sparsamt förekommande eller saknas. Öppna kvalitativa intervjuer har genomförts med 65 informanter. Studierna visade att föräldrar till barn med funktionsnedsättning samt vuxna personer med kognitiva och/eller fysiska funktionsnedsättningar inte prioriterade den orala hälsan på grund av att andra mer akuta problem upplevdes som viktigare. Många personer med funktionsnedsättning vårdas kortare eller längre tid på vårdinrättningar, men kunskapen om oral hälsa var låg och inte prioriterad av personal inom hälso- och sjukvården. Personer med funktionsnedsättning återfinns inom såväl allmäntandvård som specialisttandvård och kunskapen om dessa patienters vårdbehov och bemötande av dem varierade mycket mellan olika kliniker, allmän- och specialisttandvård och mellan olika tandvårdspersonal. Sammantaget utgör dessa resultat en möjlig förklaring till varför personer med funktionsnedsättning löper ökad risk för oral ohälsa. Detta innebär också att en prioriterad, god oral hälsa och ett adekvat bemötande av personer med funktionsnedsättningar snarare kan handla om tur än om en jämlik rättighet

The cooling of spent carbon anodes in the aluminium smelting industry : a thesis presented in partial fulfilment of the requirements for the degree of Master of Science in Mathematics at Massey University

As part of the New Zealand Aluminium Smelters (NZAS) upgrade, a hot butt cleaning system has been proposed, this would remove the bath from anodes as they are removed from the cells. It is expected that the time to cool for hot cleaned anodes would be significantly less than for current method of allowing the butts to cool before the bath is removed. In this project a mathematical model of the cooling process of both the clean and dirty anodes is developed. This model will aid in the investigation of the hot butt cleaning system by showing the difference in cooling times between the clean and dirty anodes. The temperature profiles within both clean and dirty anodes is calculated for one-, two- and three-dimensional models. Temperature changes in the anodes with time are also compared to experimental data

The FERRUM project: Experimental lifetimes and transition probabilities from highly excited even 4d levels in Fe ii

We report lifetime measurements of the 6 levels in the 3d6(5D)4d e6G term in Fe ii at an energy of 10.4 eV, and f -values for 14 transitions from the investigated levels. The lifetimes were measured using time-resolved laser-induced fluorescence on ions in a laser-produced plasma. The high excitation energy, and the fact that the levels have the same parity as the the low-lying states directly populated in the plasma, necessitated the use of a two-photon excitation scheme. The probability for this process is greatly enhanced by the presence of the 3d6(5D)4p z6F levels at roughly half the energy difference. The f -values are obtained by combining the experimental lifetimes with branching fractions derived using relative intensities from a hollow cathode discharge lamp recorded with a Fourier transform spectrometer. The data is important for benchmarking atomic calculations of astrophysically important quantities and useful for spectroscopy of hot stars.Comment: A&A, accepte

Evidence against anomalous compositions for giants in the Galactic Nuclear Star Cluster

Very strong Sc I lines have been found recently in cool M giants in the Nuclear Star Cluster in the Galactic Center. Interpreting these as anomalously high scandium abundances in the Galactic Center would imply a unique enhancement signature and chemical evolution history for nuclear star clusters, and a potential test for models of chemical enrichment in these objects. We present high resolution K-band spectra (NIRSPEC/Keck II) of cool M giants situated in the solar neighborhood and compare them with spectra of M giants in the Nuclear Star Cluster. We clearly identify strong Sc I lines in our solar neighborhood sample as well as in the Nuclear Star Cluster sample. The strong Sc I lines in M giants are therefore not unique to stars in the Nuclear Star Cluster and we argue that the strong lines are a property of the line formation process that currently escapes accurate theoretical modeling. We further conclude that for giant stars with effective temperatures below approximately 3800 K these Sc I lines should not be used for deriving the scandium abundances in any astrophysical environment until we better understand how these lines are formed. We also discuss the lines of vanadium, titanium, and yttrium identified in the spectra, which demonstrate a similar striking increase in strength below 3500 K effective temperature.Comment: 11 pages, 6 figures, accepted for publication in Ap

Multiconfiguration Dirac-Hartree-Fock calculations of atomic electric dipole moments of 225^Ra, 199^Hg, and 171^Yb

The multiconfiguration Dirac-Hartree-Fock (MCDHF) method has been employed to calculate atomic electric dipole moments (EDM) of 225^Ra, 199^Hg, and 171^Yb. For the calculations of the matrix elements we extended the relativistic atomic structure package GRASP2K. The extension includes programs to evaluate matrix elements of (P, T)-odd e-N tensor-pseudotensor and pseudoscalar-scalar interactions, the atomic electric dipole interaction, the nuclear Schiff moment, and the interaction of the electron electric dipole moment with nuclear magnetic moments. The interelectronic interactions were accounted for through valence and core-valence electron correlation effects. The electron shell relaxation was included with separately optimised wave functions of opposite parities