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Natural lifetimes were measured by time-resolved observation of laser-induced fluorescence. Free Ce, Ce+, and Ce++ particles were obtained in a laser-produced plasma. Lifetimes were measured for eight levels of singly ionized cerium, as well as for nine levels of doubly ionized cerium. The lifetime data were compared with previously published experimental and theoretical results.

https://www.wings.lu.se/article/wings-annual-conference-2017 - 2026-05-27

In this project spectra of neutral calcium between 2000-30000 cm-1 have been recorded by the Fourier Transform Spectrometer Bruker HR IRFTS at Lund Observatory. Using 204 spectral lines, 78 energy levels in the calcium atom have been derived. Level mixing and self absorption of some transitions are discussed. The energy levels in the previously not resolved triplet 4s5g 3G have been measured in th

Vi undersöker strukturen och stabiliteten hos fixpunkter i en modell för transport av auxin. Arbetet bygger vidare p*a tidigare arbeten av Anders Svensson och Patrik Sahlin m.fl. Svensson undersökte 2008 en modell för transport av auxin, den s.k. skalningsmodellen. I detta arbete kompletterar vi dels denna undersökning, och dels så generaliserar vi modellen till två dimensioner och undersöker den

Seventeen globular clusters in the Large and Small Magellanic Clouds were observed in the mid-infrared wavelength region with the ISOCAM instrument on board the Infrared Space Observatory (ISO). Observations were made using the broadband filters LW1, LW2, and LW10, corresponding to the effective wavelengths of 4.5, 6.7, and 12 mum, respectively. We present the photometry of point sources in each c

The limiting accuracy for measuring the location of an optical image is set by diffraction and photon noise, i.e., by the dual wave-particle nature of light. A theoretical expression for the limiting accuracy is derived under idealized conditions and generalized to take into account more realistic circumstances, such as additive noise and finite pixel size. Its application is discussed in relation

The weighted oscillator strengths (gf) and lifetimes for S VIII presented in this work were obtained by a multiconfigurational Hartree-Fock relativistic approach. In this calculation, the electrostatic energy parameters were optimized by a least-squares procedure in order to improve the adjustment to experimental energy levels. The values for gf and lifetimes were then calculated on the basis of t

https://www.intramed.lu.se/en/article/creativity-forum-medicum-mental-health-focus - 2026-05-27

Understanding the patterns of evolutionary sequence divergence is fundamental for comparative analyses like phylogenetics or genomics. The rate at which the different sites of protein sequences evolve is multifactorial and the causes of variation among them are highly convoluted. Inference methods have been developed to estimate site-specific evolution rates from sequence alignments. Moreover, sev

Bio-inspired crossover:Natural genomes are affected by various kinds of mutations, manifesting as variations in the genome. This includes modifications to individual base pairs (single nucleotide polymorphism, SNP), but also short insertions and deletions (indels), and variations in the position (translocations) or multiplicity (copy number variations) of genetic sequences. While SNPs are historic

We show how to resum neutral propagators to all orders in partially quenched chiral perturbation theory. We calculate the relevant quantities to next-to-next-to-leading order (NNLO). Using these results we show how to extend the proposal by Sharpe and Shoresh for determining the parameters relevant for the eta mass from partially quenched lattice QCD calculations to NNLO.

This paper presents a first study of the pseudoscalar meson masses to two loops, or next-to-next-to-leading order, within the supersymmetric formulation of partially quenched chiral perturbation theory (PQchiPT). The expression for the pseudoscalar meson mass in the case of three valence and three sea quarks with equal masses, but different from each other, is given to O(p(6)), along with a numeri

Radiative lifetimes of 7 odd and 11 even parity states of Tb I (Z = 65) have been measured by the time resolved laser induced fluorescence method (TR-LIF). Experimental data for 9 out of the 18 states are obtained for the first time. The radiative lifetimes presented in this study are in good agreement with previous TR-LIF experimental results but systematically shorter than those obtained by the

The production of jets is studied in collisions of virtual photons, γ* and γ*γ*, specifically for applications at HERA and LEP2. Photon flux factors are convoluted with matrix elements involving either direct or resolved photons and, for the latter, with parton distributions of the photon. Special emphasis is put on the range of uncertainty in the modeling of the resolved component. The resulting

This article is over 5 years old, and the information may therefore be outdated. As a young man, when Mats Bohgard was working at a chemical factory during a leave from studies, he was urged to “Come back and fix the work environment to make it fit for human beings!”. Mats Bohgard. “Even though they said it half-jokingly, the truth is that they were experiencing every conceivable work environment

https://www.staff.lu.se/article/work-environment-champion - 2026-05-27

We argue that ine + e –-annihilation (including -decay) deuteron production should be given by the overlap of the deuteron wave function with the wave function of apn-pair. The production rate depends sensitively upon the size of the production region. Taking into account the strong correlation between protons and neutrons, experimental results for -decay are consistent with the size expected in t

We derive a partition function for the Lund fragmentation model and compare it with that of a classical gas. For a fixed rapidity “volume” this partition function corresponds to a multiplicity distribution which is very close to a binomial distribution. We compare our results with the multiplicity distributions obtained from the JETSET Monte Carlo for several scenarios. Firstly, for the fragmentat

The existing Chiral Perturbation Theory (ChPT) calculations at order p⁶ are reviewed. The principles of ChPT and how they are used are introduced. The main part is a review of the two- and three-flavour full two-loop calculations and their comparison with experiment. We restrict the discussion to the mesonic purely strong and semileptonic sector. The review concludes by mentioning the e