Attosecond interferometry: techniques and spectroscopy

The interaction between an intense laser pulse and a gas medium leads to the emission of coherent bursts of light in the extreme ultraviolet range. This process, known as high-order harmonic generation, has today, almost three decades after its discovery, developed into a reliable source of extremely short (on the order of 100 as) pulses of electromagnetic radiation, with a wide range of applications in the atomic, molecular and optical sciences. The access to radiation with attosecond duration opens up new possibilities for studying and even controlling electronic processes that take place on this timescale. This thesis presents a series of experiments where sequences of attosecond pulses, attosecond pulse trains, are used to perform photoelectron interferometry. Free electronic wave packets, launched via photoabsorption of a coherent train of ionizing attosecond pulses, are manipulated by an infrared laser field and brought to interfere. From the resulting interferogram the phase of the escaping wave packets can be partly reconstructed. This phase in turn carries a signature of the interactions that lead to the ejection of the electron. Under certain conditions the measured phase can be related to a delay of the wave packet, corresponding to the time it takes for it to escape the ionic binding potential, called photoionization time delay. This method was applied to a range of atomic systems and ejection mechanisms in order to study the influence of atomic electronic structure on the ejection of electrons. Since the composition of the electronic wave packets is partly determined by the temporal structure of the ionizing radiation, a comparative approach was applied to isolate the effect of the ion-electron interactions. The photoionization time delay for ionization from the 3s subshell of argon was measured relative to that of the 3p shell. In another experiment the delay of a two electron wave packet resulting from double ionization of xenon was referenced to single ionization from the valence shell. In an iterative measurement procedure, interferograms were cross-referenced from ionization of the valence shells of argon, helium and neon. Finally, the significant phase distortion resulting from an autoionizing resonance in argon was mapped out by stepwise tuning the central frequency of the exciting pulse train. The interferometric method was also utilized to study the temporal synchronization between the attosecond pulse train and the laser pulse used to produce it. The results show that the synchronization is dependent on the density of the gaseous medium due to the specific dispersion properties of the gas

Explaining employees’ reactions towards a cross-border merger:the role of English language fluency

In this paper, we focus on the role of language in cross-border mergers and acquisitions and explore how organization members’ language skills, or fluency, in the adopted lingua franca may impact their reactions to a merger. Drawing on a qualitative study of the post-merger integration between a French and Dutch airline where English was adopted as a lingua franca, we illustrate how language fluency influences the ability of individuals to give meaning to their changed circumstances. Moreover, we elaborate on how language fluency indexes social groupings and identities, and may thus be a driver of perceptions of status inequality and identity politics between different groups of employees. With our study we draw attention to the multi-faceted role of English as a lingua franca. Our findings also contribute to research on sociocultural dynamics associated with post-merger integration and the role of language in mergers and acquisitions, as well as in multinational companies more generally

Kopplingar mellan interna prestationsmätningar och ständig förbättring

Kopplingar mellan interna prestationsmätningar och ständig förbättring undersöks genom fallstudie av IKEA Food Service. Uppsatsen genererar fem hypoteser kring ämnet

Impact of the East African Rift System on the routing of the deep‐water drainage network offshore Tanzania, western Indian Ocean

Peer reviewedPostprin

Ending preventable child deaths in South Africa: What role can ward-based outreach teams play?

South Africa (SA) has emerged from the Millennium Development Goal era with a mixture of success and failure. The successful national scale-up of prevention of mother-to-child transmission of HIV services with increasingly efficacious antiretroviral regimens has reduced the mother-to-child transmission rate dramatically; however, over the same period there appears to have been no progress in coverage of high-impact interventions for pneumonia and diarrhoea, which are now leading causes of under-5 mortality. SA embarked on a strategy to re-engineer the primary healthcare system in 2011, which included the creation of ward-based outreach teams consisting of community health workers (CHWs). In this article we argue that the proposed ratio of CHWs to population is too low for public health impact and that the role and scope of CHWs should be extended beyond giving of health information to include assessment and treatment of childhood illnesses (particularly diarrhoea and suspected pneumonia). Evidence and experience amply demonstrate that CHWs in sufficient density can have a rapid and positive impact on neonatal and young child mortality, especially when they are allowed to treat common acute conditions. SA’s mediocre performance in child survival could be dramatically improved if there were more CHWs who were allowed to do more

Child mortality in South Africa: Is the Sustainable Development Goal (3.2) target achievable with current efforts?

The two articles by Bamford et al.[1,2] in the recent SAMJ Maternal and Child Health Supplement present trends in inpatient case fatality rates for diarrhoeal disease, pneumonia and severe acute malnutrition (SAM), and a review of under-5 mortality and cause of death using several sources of nationally representative data. While these reviews provide evidence of some improvement, seemingly limited to the impact of prevention of mother-to-child transmission roll-out, we have some comments related to the interpretation of the data