| 1. |
- Afzelius, M., et al.
(författare)
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Proposal for a coherent quantum memory for propagating microwave photons
- 2013
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Ingår i: New Journal of Physics. - : IOP Publishing. - 1367-2630. ; 15, s. Art. no. 065008-
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Tidskriftsartikel (refereegranskat)abstract
- We describe a multi-mode quantum memory for propagating microwave photons that combines a solid-state spin ensemble resonantly coupled to a frequency tunable single-mode microwave cavity. We first show that high efficiency mapping of the quantum state transported by a free photon to the spin ensemble is possible both for strong and weak coupling between the cavity mode and the spin ensemble. We also show that even in the weak coupling limit unit efficiency and faithful retrieval can be obtained through time reversal inhomogeneous dephasing based on spin echo techniques. This is possible provided that the cavity containing the spin ensemble and the transmission line are impedance matched. We finally discuss the prospects for an experimental implementation using a rare-earth doped crystal coupled to a superconducting resonator.
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| 2. |
- Boo Höglund, Eva, 1959-
(författare)
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Vetenskapens verklighet : Om motsättningen mellan realism och konstruktivism i vetenskapsfilosofin
- 2002
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- This thesis investigates the conflict between a constructivist and a realist understanding of scientific theories. It focuses on the constructivism formulated by Thomas S. Kuhn and the realism formulated by Richard Boyd, but also relates these conceptions to other forms of constructivism and realism described in the literature.Chapter 1 presents ideas that are claimed to anticipate Kuhn’s constructivism. Among topics discussed are Ludwig Wittgenstein’s idea that the basic principles of Newtonian mechanics determine the form of the scientific description and Pierre Duhem’s idea of natural classifications. Chapter 2 gives an introduction to the constructivist aspects of Kuhn’s philosophy of science. Chapter 3 presents Boyd’s realism and Chapter 4 involves a comparison of Kuhn’s and Boyd’s conceptions of reference. Chapter 5 argues that Boyd’s way of describing the conflict between constructivism and realism is misleading. It shows that Boyd takes a philosophical discourse for granted in his description of scientific theories; a discourse consisting of a set of terms and expressions and a specific way of using these terms and expressions. Kuhn also uses a philosophical discourse in his description of scientific theories, a discourse that is different from Boyd’s and unlike Boyd he introduces it explicitly, rather than takes it for granted. As the main result of the chapter (and of the dissertation) it is argued that the conflict between constructivism and realism is best understood as an opposition between different philosophical discourses or languages. Chapter 5 further investigates the claim of general applicability expressed in Boyd’s and Kuhn’s theories. It argues that this claim is, in a sense, built into the philosophical languages they use. In connection with a constructivist and a realist interpretation of two biological theories (Hennig’s phylogentic systematics and Linnaeus’ essentialist systematics), it is suggested that the generality claims are unfounded and should be rejected. Chapter 5 ends by suggesting that the way of understanding the conflict between scientific realism and constructivism proposed in this thesis, namely as a conflict between different philosophical discourses or languages, applies also to other conflicts in contemporary philosophy of science.
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| 3. |
- Brack, A., et al.
(författare)
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Origin and Evolution of Life on Terrestrial Planets
- 2010
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Ingår i: Astrobiology. - : Mary Ann Liebert Inc. - 1531-1074 .- 1557-8070. ; 10:1, s. 69-76
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Tidskriftsartikel (refereegranskat)abstract
- The ultimate goal of terrestrial planet-finding missions is not only to discover terrestrial exoplanets inside the habitable zone (HZ) of their host stars but also to address the major question as to whether life may have evolved on a habitable Earth-like exoplanet outside our Solar System. We note that the chemical evolution that finally led to the origin of life on Earth must be studied if we hope to understand the principles of how life might evolve on other terrestrial planets in the Universe. This is not just an anthropocentric point of view: the basic ingredients of terrestrial life, that is, reduced carbon-based molecules and liquid H2O, have very specific properties. We discuss the origin of life from the chemical evolution of its precursors to the earliest life-forms and the biological implications of the stellar radiation and energetic particle environments. Likewise, the study of the biological evolution that has generated the various life-forms on Earth provides clues toward the understanding of the interconnectedness of life with its environment.
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| 4. |
- Brack, Werner, et al.
(författare)
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The SOLUTIONS project : Challenges and responses for present and future emerging pollutants in land and water resources management
- 2015
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Ingår i: Science of the Total Environment. - : Elsevier BV. - 0048-9697 .- 1879-1026. ; 503, s. 22-31
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Tidskriftsartikel (refereegranskat)abstract
- SOLUTIONS (2013 to 2018) is a European Union Seventh Framework Programme Project (EU-FP7). The project aims to deliver a conceptual framework to support the evidence-based development of environmental policies with regard to water quality. SOLUTIONS will develop the tools for the identification, prioritisation and assessment of those water contaminants that may pose a risk to ecosystems and human health. To this end, a new generation of chemical and effect-based monitoring tools is developed and integrated with a full set of exposure, effect and risk assessment models. SOLUTIONS attempts to address legacy, present and future contamination by integrating monitoring and modelling based approaches with scenarios on future developments in society, economy and technology and thus in contamination. The project follows a solutions-oriented approach by addressing major problems of water and chemicals management and by assessing abatement options. SOLUTIONS takes advantage of the access to the infrastructure necessary to investigate the large basins of the Danube and Rhine as well as relevant Mediterranean basins as case studies, and puts major efforts on stakeholder dialogue and support. Particularly, the EU Water Framework Directive (WFD) Common Implementation Strategy (CIS) working groups, International River Commissions, and water works associations are directly supported. with consistent guidance for the early detection, identification, prioritisation, and abatement of chemicals in the water cycle. SOLUTIONS will give a specific emphasis on concepts and tools for the impact and risk assessment of complex mixtures of emerging pollutants, their metabolites and transformation products. Analytical and effect-based screening tools will be applied together with ecological assessment tools for the identification of toxicants and their impacts. The SOLUTIONS approach is expected to provide transparent and evidence-based candidates or River Basin Specific Pollutants in the case study basins and to assist future review of priority pollutants under the WFD as well as potential abatement options.
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| 5. |
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| 6. |
- Brackley, Karen I., 1982, et al.
(författare)
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Activities of the chaperonin containing TCP-1 (CCT): implications for cell cycle progression and cytoskeletal organisation.
- 2009
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Ingår i: Cell Stress and Chaperones. - : Springer Science and Business Media LLC. - 1355-8145 .- 1466-1268. ; 14:1, s. 23-31
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Forskningsöversikt (refereegranskat)abstract
- The chaperonin containing TCP-1 (CCT) is required for the production of native actin and tubulin and numerous other proteins, several of which are involved in cell cycle progression. The mechanistic details of how CCT acts upon its folding substrates are intriguing: whilst actin and tubulin bind in a sequence-specific manner, it is possible that some proteins could use CCT as a more general binding interface. Therefore, how CCT accommodates the folding requirements of its substrates, some of which are produced in a cell cycle-specific manner, is of great interest. The reliance of folding substrates upon CCT for the adoption of their native structures results in CCT activity having far-reaching implications for a vast array of cellular processes. For example, the dependency of the major cytoskeletal proteins actin and tubulin upon CCT results in CCT activity being linked to any cellular process that depends on the integrity of the microfilament and microtubule-based cytoskeletal systems.
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| 7. |
- Brackmann, Christian, et al.
(författare)
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Characterization of ammonia two-photon laser-induced fluorescence for gas-phase diagnostics
- 2014
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Ingår i: Applied Physics B. - : Springer Science and Business Media LLC. - 0946-2171 .- 1432-0649. ; 115:1, s. 25-33
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Tidskriftsartikel (refereegranskat)abstract
- Two-photon laser-induced fluorescence (LIF) of ammonia (NH3) with excitation of the C'-X transition at 304.8 nm and fluorescence detection in the 565 nm C'-A band has been investigated, targeting combustion diagnostics. The impact of laser irradiance, temperature, and pressure has been studied, and simulation of NH3-spectra, fitted to experimental data, facilitated interpretation of the results. The LIF-signal showed quadratic dependence on laser irradiance up to 2 GW/cm(2). Stimulated emission, resulting in loss of excited molecules, is induced above 10 GW/cm(2), i.e., above irradiances attainable for LIF imaging. Maximum LIF-signal was obtained for excitation at the 304.8 nm bandhead; however, lower temperature sensitivity over the range 400-700 K can be obtained probing lines around 304.9 nm. A decrease in fluorescence signal was observed with pressure up to 5 bar absolute and attributed to collisional quenching. A detection limit of 800 ppm, at signal-to-noise ratio 1.5, was identified for single-shot LIF imaging over an area of centimeter scale, whereas for single-point measurements, the technique shows potential for sub-ppm detection. Moreover, high-quality NH3-imaging has been achieved in laminar and turbulent premixed flames. Altogether, two-photon fluorescence provides a useful tool for imaging NH3-detection in combustion diagnostics.
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| 8. |
- Grandi, Giulio, et al.
(författare)
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Detection of Tick-Borne Pathogens in Lambs Undergoing Prophylactic Treatment Against Ticks on Two Swedish Farms
- 2018
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Ingår i: Frontiers in Veterinary Science. - : Frontiers Media SA. - 2297-1769. ; 5
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Tidskriftsartikel (refereegranskat)abstract
- Tick-borne pathogens (TBPs), especially Anaplasma phagocytophilum, cause disease in grazing livestock. Tick prophylaxis is, therefore, a routine practice in sheep flocks in Sweden, especially in central, southern, and coastal areas of the country where ixodid ticks (Ixodes ricinus and Haemaphysalis punctata) are present. In the present study, the status of infection by A. phagocytophilum and other TBPs in lambs treated with tick prophylaxis has been assessed serologically and with polymerase chain reaction (PCR). Blood samples (n = 78) from lambs (n = 20) subjected to regular tick prophylactic treatment (flumethrin, Bayticol (R)) at two sites in different regions in Sweden (Ostergotland, Gotland) were collected on four occasions from May until July 2013. The severity of clinical signs in Anaplasma-infected animals is known to differ between these two regions. In total, 20% of blood samples were PCR-positive for A. phagocytophilum. Serological analyses showed that 33% of all collected samples were positive for A. phagocytophilum, while 2.5% were positive for Borrelia burgdorferi s.l. and 13% for tick-borne encephalitis virus (TBEV). Percentages of lambs positive were 75 and 45% for A. phagocytophilum antibodies and DNA, respectively, while 10 and 45% were serologically positive for B. burgdorferi s.l. and TBEV, respectively. Sequencing of partial 16S rRNA genes from Anaplasma PCR positive samples revealed presence of A. phagocytophilum in all animals in Ostergotland, while sequences consistent with A. phagocytophilum as well as A. capra and A. bovis were found on the island of Gotland. This is the first report of the occurrence of the latter two species in Sweden.
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| 9. |
- Grandi, Giulio
(författare)
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Exposure to amitraz, fipronil and permethrin affects cell viability and ABC transporter gene expression in an Ixodes ricinus cell line
- 2018
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Ingår i: Parasites and Vectors. - : Springer Science and Business Media LLC. - 1756-3305. ; 11
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Tidskriftsartikel (refereegranskat)abstract
- Background: Over-expression of ATP-binding cassette (ABC) transporter proteins has been implicated in resistance of ticks to acaricides. Tick cell lines are useful for investigating resistance mechanisms, as development of an in vitro model for the study of acaricide resistance would contribute to improving knowledge of the molecular basis behind drug processing and exclusion in ticks. In the present study, cultures of the Ixodes ricinus-derived cell line IRE/CTVM19 were treated with the acaricides amitraz, permethrin or fipronil to determine modulation of ABC transporter gene expression. Cells were treated with different drug concentrations (25, 50, 100, 150 mu M) and incubated for ten days. Cell morphology, viability, metabolic activity and relative expression of ABC (B1, B6, B8 and B10) genes were determined at day 10 post-treatment.Results: Cell morphology determined by light microscopy was altered following treatment with all drugs, but only at high concentrations, while total cell numbers decreased with increasing drug dose. Cell viability determined by trypan blue exclusion was not significantly different from untreated controls (P > 0.1) following treatment with amitraz and permethrin, but high concentrations of fipronil caused decrease (up to 37%, P < 0.01) in viability. At all drug concentrations, fipronil and permethrin induced dose-dependent reduction in cell metabolic activity measured by MTT assay (P < 0.01). Quantitative RT-PCR showed that the drugs significantly affected expression of ABC genes. In particular, fipronil treatment downregulated ABCB1 (P < 0.001) and upregulated ABCB6, ABCB8 and ABCB10 (P < 0.01); amitraz treatment down regulated ABCB1 (significant difference between 25 and 150 mu M, P < 0.001) and upregulated ABCB8 and ABCB10 at lower concentrations (25 and 50 mu M, P < 0.05); and permethrin upregulated ABCB6, ABCB8 and ABCB10 only at 150 mu M (P < 0.01).Conclusions: The adverse effects on cell viability and metabolic activity, and changes in expression of different ABC transporter genes, detected in IRE/CTVM19 cells following treatment with amitraz, permethrin and fipronil, support the proposed application of tick cell lines as in vitro models for the study of resistance to these acaricides in ticks.
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| 10. |
- Grandi, Gabriele, 1965-, et al.
(författare)
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Implementation of carrier-based optimized centered PWM in three-phase three-level inverters
- 2014
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Konferensbidrag (refereegranskat)abstract
- Carrier-based modulation is widely adopted since it offers some benefits compared to space-vector modulation in both two-level and multilevel inverters, such as inherent simplicity, flexibility, reduced computational times, and possibility of implementation on industrial DSPs. Among the numerous types of PWM techniques, the centered PWM (CPWM) is nearly optimal modulation, since it minimizes the RMS of output current harmonics. Despite of CPWM is easy to implement in two-level inverters, the complexity increases in case of three-level and multilevel inverters. In this paper a simplified straight procedure to implement carrier-based optimized CPWM for three-level inverter is presented, equivalent to centered space vector modulation. The proposed method has been implemented by numerical simulations, considering the comparison of resulting modulating signals with the other methods existing in literature and verifying the pulse centering in the output phase voltage waveforms.
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