Nonlinear state space smoothing using the conditional particle filter

To estimate the smoothing distribution in a nonlinear state space model, we apply the conditional particle filter with ancestor sampling. This gives an iterative algorithm in a Markov chain Monte Carlo fashion, with asymptotic convergence results. The computational complexity is analyzed, and our proposed algorithm is successfully applied to the challenging problem of sensor fusion between ultra-wideband and accelerometer/gyroscope measurements for indoor positioning. It appears to be a competitive alternative to existing nonlinear smoothing algorithms, in particular the forward filtering-backward simulation smoother.Comment: Accepted for the 17th IFAC Symposium on System Identification (SYSID), Beijing, China, October 201

Multimetal smithing : An urban craft in rural settings?

Multimetal smithing should be defined as the use of more than one metal and/or different metalworking techniques within thesame crafts-milieu. This complex metalworking has long been linked to centrality, central places and urbanity in Scandinavia.It has been extensively argued that fine casting and smithing, as well as manufacture utilizing precious metals was exclusivelyundertaken within early urban settings or the “central places” pre-dating these. Furthermore, the presence of complex metalcraftsmanship has been used as a driving indicator of the political, social and economic superiority of certain sites, therebyenhancing their identity as “centralities”.Recent research has come to challenge the universality of this link between urbanity, centrality and complex metalworkingas sites in rural settings with evidence of multimetal smithing are being identified. This shows that the relationship between thecraft and centrality (urbanity) must be nuanced and that perhaps multimetal craftsmanship should be reconsidered as an urbanindicator.The thesis project “From Crucible and onto Anvil” started in 2015 and focuses on sites housing remains of multimetalcraftsmanship dating primarily from 500-1000 AD. Within the project a comprehensive survey of sites will be used to evaluate thepresence of multimetal craftsmanship in the landscape. Sites in selected target areas will also be subject to intra-site analysisfocusing on workshop organisation, production output, metalworking techniques and chronological variances.A key aim in the project is to elucidate the conceptual aspects of complex metalworking. The term multimetality is used toanalytically frame all the societal and economic aspects of multimetal craftsmanship. Through this inclusive perspective both thecraftsmanship and the metalworkers behind it are positioned within the overall socioeconomic framework. The metalworkers,their skills and competences as well as the products of their labour are viewed as dynamic actors in the landscape and on thearenas of political economy of the Late Iron Age.The survey has already revealed interesting aspects concerning multimetal smithing and urbanity. Although the multimetalsites do cluster against areas of early urban development there are also other patterns emerging. Multimetal craftsmanship – both as practice and concept – was well represented in both rural peripheral settings and urban crafts-milieus. This means that therole of multimetality as part of an “urban conceptual package” is crucial to investigate. Such an approach will have the dual endsof properly understanding the craft and its societal implications, but also further the knowledge of the phenomenon of urbanityas a whole. Was multimetal smithing part of an “urban package” that spread into the rural landscape? Did the multimetality differbetween urban and rural crafts-milieus? How does early urbanity relate to the chronology of multimetal craftsmanship?This paper aims to counter these questions using examples from the survey of multimetal sites conducted within the thesisproject. A comparison between selected sites will be presented. The purpose of this is to evaluate the role of multimetality withinthe “urban package” and discuss the role of complex metalworking in the establishment of urban arenas of interaction in LateIron Age Scandinavia

Complex Metalworking in the Provinces, Rural Centres and Towns. Preliminary Results from the project "Exclusive Metalworking in Rural Settings" contextualized

The research project “Exclusive Metalworking in Rural Settings” was instigated in 2013 with funding from the Berit Wallenberg Foundation. The objective of the project is to survey sites with remains of multimetal craftsmanship of the late Iron Age and medieval periods outside urban contexts. This article aims to contextualize preliminary results from the project and evaluate its chosen source material and methodology. The survey has so far identified several complex smithing sites in the rural and nearurban landscape. The multimetal sites are divisible into three categories: sites in the vicinity of towns, sites related to central places and more or less independent provincial sites. Sites from each of these categories are presented below and the results that the macrolevel survey has yielded as to the multimetal craftsmanship conducted are analysed. The results are then used to pursue a broader discussion concerning the conceptual aspects of complex metalworking – multimetality in the landscape

Mesenchymal stromal cells in malignant glioma - Functions and therapeutic potential

The most common malignant brain tumor in adults is a glioma called glioblastoma multiforme (GBM). About 300 persons are diagnosed with GBM every year in Sweden. Unfortunately, it is also the most aggressive brain tumor and as of today, it is not possible to cure it. Despite treating the patients with surgery, radiation and chemotherapy, the median survival is only 15 months. The main problem with GBM is its infiltrative growth. As the tumor cells leave the tumor bulk and migrate into the normal brain parenchyma, it is impossible to reach them with the current standard treatments. Hence, even after treatment, some tumor cells will remain in the brain and eventually give rise to a new tumor. To be able to reach the migrating cells, new treatment strategies need to be developed. One such strategy is to use stem cells as drug delivery vehicles. It has been shown that mesenchymal stromal cells (MSCs) derived from the bone marrow (BM) have the ability to specifically migrate throughout a glioma. Upon intratumoral transplantation, they spread within the tumor, along its extensions and toward migrating tumor cells that has left the main tumor bulk, making BM-MSCs ideal as transporters of anti-tumoral substances. However, several safety concerns have been raised as MSCs also have shown to mediate tumor growth by acting immunosuppressive and contribute to the tumor stroma and vascularization. This thesis will discuss 1) the role of endogenous MSCs in malignant glioma and 2) the use of transplanted BM-MSCs as glioma treatment. We have shown that human malignant gliomas harbor two distinct cell populations that resemble BM-MSCs. We have characterized the cells and conclude that they most likely play an important role in tumor angiogenesis and immunosuppression. Further on, we have seen that MSC-like pericytes within the normal mouse brain are activated by, and migrate into, an orthotopic glioma model. The cells align perivascularly and contribute the majority of all pericytes within the tumor. To evaluate their tumor-tropism, MSCs were derived from rat bone marrow and transplanted into, and adjacent to, orthotopic rat gliomas. We conclude that even though they show strong tumor-tropic migration capabilities upon intratumoral transplantation they do not migrate when transplanted into the normal brain of tumor bearing animals. We also report that intratumorally transplanted BM-MSCs potentiate the effect of peripheral immunotherapy against malignant gliomas, demonstrating their use in a therapeutic setting

Period-tripling subharmonic oscillations in a driven superconducting resonator

We have observed period-tripling subharmonic oscillations, in a superconducting coplanar waveguide resonator operated in the quantum regime, $k_B T \ll \hbar\omega$. The resonator is terminated by a tunable inductance that provides a Kerr-type nonlinearity. We detected the output field quadratures at frequencies near the fundamental mode, $\omega/2\pi \sim 5\,$GHz, when the resonator was driven by a current at $3\omega$ with an amplitude exceeding an instability threshold. The output radiation was red-detuned from the fundamental mode. We observed three stable radiative states with equal amplitudes and phase-shifted by $120^\circ$. The downconversion from $3\omega$ to $\omega$ is strongly enhanced by resonant excitation of the second mode of the resonator, and the cross-Kerr effect. Our experimental results are in quantitative agreement with a model for the driven dynamics of two coupled modes