165 research outputs found

    Neural and behavioral plasticity in olfactory sensory deprivation

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    The human brain has a remarkable ability to reorganize as a consequence of altered demands. This ability is particularly noticeable when studying the neural effects of complete sensory deprivation. Both structural and functional cerebral reorganization have repeatedly been demonstrated in individuals with sensory deprivation, most evident in cortical regions associated with the processing of the absent sensory modality. Furthermore, sensory deprivation has been linked to altered abilities in remaining sensory modalities, often of a compensatory character. Although anosmia, complete olfactory sensory deprivation, is our most common sensory deprivation, estimated to affect around 5 % of the population, the effects of anosmia on brain and behavior are still poorly understood. The overall aim of this thesis was to investigate how the human brain and behavior are affected by anosmia, with a focus on individuals with congenital (lifelong) sensory deprivation. Specifically, Study I and Study IV assessed potential behavioral and neural multisensory compensatory abilities whereas Study II and Study III assessed potential reorganization beyond the processing of specific stimuli; the latter by determining morphological and resting-state functional connectivity alterations. Integration of information from different sensory modalities leads to a more accurate perception of the world around us, given that our senses provide complementary information. Although an improved ability to extract multisensory information would be of particular relevance to individuals deprived of one sensory modality, multisensory integration has been sparsely studied in relation to sensory deprivation. In Study I, multisensory integration of audio-visual stimuli was assessed in individuals with anosmia using two different experimental tasks. First, individuals with anosmia were better than matched controls in detecting multisensory temporal asynchronies in a simultaneity judgement task. Second, individuals with congenital, but not acquired, anosmia demonstrated indications of an enhanced ability to utilize multisensory information in an object identification task with degraded stimuli. Based on these results, the neural correlates of audio-visual processing and integration were assessed in individuals with congenital anosmia in Study IV. Relative to matched normosmic individuals, individuals with congenital anosmia demonstrated increased activity in established multisensory regions when integrating degraded audio-visual stimuli; however, no compensatory cross-modal processing in olfactory regions was demonstrated. Together, Study I and IV suggest that complete olfactory sensory deprivation is linked to enhanced audio-visual integration performance that might be facilitated by increased processing in multisensory regions. In Study II, whole-brain gray matter morphology was assessed in individuals with congenital anosmia. Both increases and decreases in the orbitofrontal cortex, a region associated with olfaction and sometimes referred to as secondary olfactory cortex, were observed in individuals with congenital anosmia in relation to matched controls. However, in contrast to our expectations, no sensory deprivation-dependent effects were demonstrated in piriform cortex, a region commonly referred to as primary olfactory cortex. Furthermore, Study III revealed an absence of differences in resting-state functional connectivity between individuals withcongenital anosmia and normosmic individuals within the primary olfactory cortex (including piriform cortex) as well as between core olfactory processing regions. In conclusion, the studies presented within this thesis suggest the existence of a potential multisensory compensatory mechanism in individuals with anosmia, but demonstrate a striking lack of morphological and functional alterations in piriform (primary olfactory) cortex. These results demonstrate that complete olfactory deprivation is associated with a distinct neural and behavioral reorganization in some regions but also a clear lack of effects in other regions; the latter underline the clear differences between our senses and suggest that extrapolating from individual senses should be done cautiously

    Positioning urban labs – a new form of smart governance?

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    In the current era, in which cities are considered key arenas for coping with a number of societal challenges, there is also renewed interest in the mobilisation of experimental practices within urban planning. A growing interest in innovative intiatives emphasising co-creation, exploration, experimentation, and evaluation, such as urban living labs must also be understood in relation to the uncertatinity regarding the modern growth paradigm and its institutional arrangements: “the pragmatist heritage of urban laboratories gains renewed strength in the current era in which the belief in modernity, progress and development is in crisis” (Karvonen & van Heur, 2014, p. 387). This paper provides a sympathetic critique of the notion of urban living labs and related expeimental practices from an urban planning and governance persepective. In this light, we argue that the core principels of urban living labs (i.e. co-creation, exploration, experimentation, and evaluation) offer a useful theortical frame to understand and position different informal self-organizing initiatives in contemporary urban development. Furthermore, we assert that, considered as a planning practice (or methodology), urban living labs can be construed as a temporary mode of soft governance which include a number of merits in terms of definig new innovative pathways for urban planning beyond business as usual thinking. However, caution must be taken due to the urban living lab’s inherent shortcomings in terms of demorcractic legitimacy, tendencies towards exclusiveness, and extreme temporality. In conclusion, we argue that urban living labs can be an environment for exploring new forms of smart urban governance through critical engagments with communicative planning theory and an explict focus on actor-relations

    Urban Planning through Exhibition and Experimentation in Stockholm

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    In this paper we discuss findings of our case study on the making and implementation of the exhibition 'Experiment Stockholm' in 2015, which, based on artistic exhibits as well as a number of forums, aimed at generating creative narratives for the sustainable urban future in the Swedish capital city-region. Our analytical framework is informed by the emerging notion of 'urban living labs' across Europe as well as 'communicative' and 'actor-relational' planning theory', which is discussed in another paper within the poceedings of this conference (cf. Schmitt et al. 2016). We argue that the exhibition 'Experiment Stockholm' and the activities around it can be characterised as a soft mode of urban governance that can help to unlock creativity and to open up avenues for experimentation and alternative solutions in urban planning. However, caution must be taken to not overvalue such approaches, as our example implies a rather exclusive expert forum instead of a a mode of governance that might be associated with openness and wider engagement. In addition, our example illustrates the significance of suitable and unconventional methods, which otherwise considerably limits the innovative capacity of the participating stakeholders and their search for alternative solutions

    Influence of volcanic eruptions on midlatitude upper tropospheric aerosol and consequences for cirrus clouds – Volc Affects S Aerosol in UT and Cirrus

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    The influence of downwelling stratospheric sulfurous aerosol on the UT (upper troposphere) aerosol concentrations and on cirrus clouds is investigated using CARIBIC (Civil Aircraft for Regular Investigation of the Atmosphere Based on an Instrument Container observations) (between 1999–2002 and 2005–2013) and the cirrus reflectance product from Moderate Resolution Imaging Spectroradiometer (MODIS). The initial period, 1999–2002, was volcanically quiescent after which the sulfurous aerosol in the LMS (lowermost stratosphere) (SLMS_{LMS}) became enhanced by several volcanic eruptions starting 2005. From 2005 to 2008 and in 2013, volcanic aerosol from several tropical eruptions increased SLMS_{LMS}. Due to consequent subsidence, the sulfur loading of the upper troposphere (SUT_{UT}) was increased by a factor of 2.5 compared to background levels. Comparison of SLMS and SUT_{UT} during the seasons March–July and August–November shows a close coupling of the UT and LMS. Finally, the relationship between SLMS_{LMS} and the cirrus cloud reflectance (CR) retrieved from MODIS spectrometer (on board the satellites Terra and Aqua) is studied. SLMS_{LMS} and CR show a strong anticorrelation, with a factor of 3.5 increase in SLMS and decrease of CR by 8 ± 2% over the period 2001–2011. We propose that the increase of SLMS_{LMS} due to volcanism has caused the coinciding cirrus CR decrease, which would be associated with a negative radiative forcing in the Northern Hemisphere midlatitudes

    Search for dark matter produced in association with bottom or top quarks in √s = 13 TeV pp collisions with the ATLAS detector

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    A search for weakly interacting massive particle dark matter produced in association with bottom or top quarks is presented. Final states containing third-generation quarks and miss- ing transverse momentum are considered. The analysis uses 36.1 fb−1 of proton–proton collision data recorded by the ATLAS experiment at √s = 13 TeV in 2015 and 2016. No significant excess of events above the estimated backgrounds is observed. The results are in- terpreted in the framework of simplified models of spin-0 dark-matter mediators. For colour- neutral spin-0 mediators produced in association with top quarks and decaying into a pair of dark-matter particles, mediator masses below 50 GeV are excluded assuming a dark-matter candidate mass of 1 GeV and unitary couplings. For scalar and pseudoscalar mediators produced in association with bottom quarks, the search sets limits on the production cross- section of 300 times the predicted rate for mediators with masses between 10 and 50 GeV and assuming a dark-matter mass of 1 GeV and unitary coupling. Constraints on colour- charged scalar simplified models are also presented. Assuming a dark-matter particle mass of 35 GeV, mediator particles with mass below 1.1 TeV are excluded for couplings yielding a dark-matter relic density consistent with measurements

    Measurement of the Tau Lepton Polarisation at LEP2

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    A first measurement of the average polarisation P_tau of tau leptons produced in e+e- annihilation at energies significantly above the Z resonance is presented. The polarisation is determined from the kinematic spectra of tau hadronic decays. The measured value P_tau = -0.164 +/- 0.125 is consistent with the Standard Model prediction for the mean LEP energy of 197 GeV.A first measurement of the average polarisation Pτ of tau leptons produced in e + e − annihilation at energies significantly above the Z resonance is presented. The polarisation is determined from the kinematic spectra of tau hadronic decays. The measured value Pτ=−0.164±0.125 is consistent with the Standard Model prediction for the mean LEP energy of 197 GeV.A first measurement of the average polarisation P_tau of tau leptons produced in e+e- annihilation at energies significantly above the Z resonance is presented. The polarisation is determined from the kinematic spectra of tau hadronic decays. The measured value P_tau = -0.164 +/- 0.125 is consistent with the Standard Model prediction for the mean LEP energy of 197 GeV

    Measurement of inclusive π0\pi^{0} production in hadronic Z0Z^{0} decays

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    An analysis is presented of inclusive \pi^0 production in Z^0 decays measured with the DELPHI detector. At low energies, \pi^0 decays are reconstructed by \linebreak using pairs of converted photons and combinations of converted photons and photons reconstructed in the barrel electromagnetic calorimeter (HPC). At high energies (up to x_p = 2 \cdot p_{\pi}/\sqrt{s} = 0.75) the excellent granularity of the HPC is exploited to search for two-photon substructures in single showers. The inclusive differential cross section is measured as a function of energy for {q\overline q} and {b \bar b} events. The number of \pi^0's per hadronic Z^0 event is N(\pi^0)/ Z_{had}^0 = 9.2 \pm 0.2 \mbox{(stat)} \pm 1.0 \mbox{(syst)} and for {b \bar b}~events the number of \pi^0's is {\mathrm N(\pi^0)/ b \overline b} = 10.1 \pm 0.4 \mbox{(stat)} \pm 1.1 \mbox{(syst)} . The ratio of the number of \pi^0's in b \overline b events to hadronic Z^0 events is less affected by the systematic errors and is found to be 1.09 \pm 0.05 \pm 0.01. The measured \pi^0 cross sections are compared with the predictions of different parton shower models. For hadronic events, the peak position in the \mathrm \xi_p = \ln(1/x_p) distribution is \xi_p^{\star} = 3.90^{+0.24}_{-0.14}. The average number of \pi^0's from the decay of primary \mathrm B hadrons is found to be {\mathrm N} (B \rightarrow \pi^0 \, X)/\mbox{B hadron} = 2.78 \pm 0.15 \mbox{(stat)} \pm 0.60 \mbox{(syst)}
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