141 research outputs found

    Monetary Policy in a Small Open Economy Model: A DSGE-VAR Approach for Switzerland

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    We study the transmission of monetary shocks and monetary policy with a behavioral model, corrected for potential misspecification using the DSGE-VAR framework elaborated by DelNegro and Schorfheide (2004). In particular, we investigate if the central bank should react to movements in the nominal exchange rate. We contribute to the empirical literature as we use Swiss data, which is very rarely used in that context.

    External control strategies for self-propelled particles: optimizing navigational efficiency in the presence of limited resources

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    We experimentally and numerically study the dependence of different navigation strategies regarding the effectivity of an active particle to reach a predefined target area. As the only control parameter, we vary the particle's propulsion velocity depending on its position and orientation relative to the target site. By introducing different figures of merit, e.g. the time to target or the total consumed propulsion energy, we are able to quantify and compare the efficiency of different strategies. Our results suggest, that each strategy to navigate towards a target, has its strengths and weaknesses and none of them outperforms the other in all regards. Accordingly, the choice of an ideal navigation strategy will strongly depend on the specific conditions and the figure of merit which should be optimized

    Efficient Radio Frequency filters for space constrained cryogenic set-ups

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    Noise filtering is an essential part for measurement of quantum phenomena at extremely low temperatures. Here, we present the design of a filter which can be installed in space constrained cryogenic environment containing a large number of signal carrying lines. Our filters have a -3db point of 65kHz and its performance at GHz frequencies are comparable to the best available RF filters.Comment: 9 pages, 4 figures, The capacitor reference in the first version was wrong and has been changed to the right on

    Theoretical, numerical, and experimental study of a flying qubit electronic interferometer

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    We discuss an electronic interferometer recently measured by Yamamoto et al. This "flying quantum bit" experiment showed quantum oscillations between electronic trajectories of two tunnel-coupled wires connected via an Aharanov-Bohm ring. We present a simple scattering model as well as a numerical microscopic model to describe this experiment. In addition, we present new experimental data to which we confront our numerical results. While our analytical model provides basic concepts for designing the flying qubit device, we find that our numerical simulations allow to reproduce detailed features of the transport measurements such as in-phase and anti-phase oscillations of the two output currents as well as a smooth phase shift when sweeping a side gate. Furthermore, we find remarkable resemblance for the magneto conductance oscillations in both conductance and visibility between simulations and experiments within a specific parameter range.Comment: 10 pages, 13 figure

    Administration of a VEGFR‑2-specific MRI contrast agent to assess orthodontic tooth movement

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    Purpose It is thought that orthodontic forces initially reduce periodontal blood flow during orthodontic tooth movement (OTM) via tissue compression with cells responding to concomitant oxygen deprivation with expression of vascular endothelial growth factor (VEGF) triggering angiogenesis via binding to its receptor VEGFR‑2. To test this hypothesis, we performed a pilot study to establish a protocol for molecular magnetic resonance imaging (MRI) of rat jaws administering a VEGFR-2-specific contrast agent. Methods Mesial OTM of a first upper left rat molar was initiated in one male Fischer 344 rat 4 days prior to MRI by insertion of an elastic band between the first and second upper molars with the contralateral side left untreated (internal control). T1-weighted MRI sequences including dynamic contrast-enhanced MRI (DCE-MRI) were recorded before and after administration of a molecular VEGFR‑2 MRI marker with a 7 T MRI dedicated for small animal use. Results After injection of anti-VEGFR2-albumin-gadolinium-DTPA, volume enhancement on T1-weighted images was increased at the OTM side distally of the moved first upper molar (M1) compared to the control side, whereas the T1 relaxation time was reduced on the OTM side. DCE-MRI resulted in an increased area under the curve (AUC), whereas time-to-peak (TTP) and washout rate were reduced during OTM distally of the moved M1 compared to the contralateral side. Conclusions OTM resulted in uptake of the VEGFR-2-specific MRI contrast agent in tension areas of the periodontal ligament. The imaging protocol presented here is useful for the assessment of VEGFR‑2 expression in tension areas of the periodontal ligament in vivo

    alpha-Synuclein: a Modulator During Inflammatory CNS Demyelination

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    Abstract Neuroinflammation and demyelination are hallmarks of several neurological disorders such as multiple sclerosis and multiple system atrophy. To better understand the underlying mechanisms of de- and regeneration in respective diseases, it is critical to identify factors modulating these processes. One candidate factor is alpha-Synuclein (aSyn), which is known to be involved in the pathology of various neurodegenerative diseases. Recently, we have shown that aSyn is involved in the modulation of peripheral immune responses during acute neuroinflammatory processes. In the present study, the effect of aSyn deficiency on de- and regenerative events in the CNS was analyzed by using two different demyelinating animal models: chronic MOG35–55-induced experimental autoimmune encephalomyelitis (EAE) and the cuprizone model. Histopathological analysis of spinal cord cross sections 8 weeks after EAE induction revealed a significant reduction of CNS inflammation accompanied by decreased myelin loss during late-stage inflammatory demyelination in aSyn-deficient mice. In contrast, after cuprizone-induced demyelination or remyelination following withdrawal of cuprizone, myelination and neuroinflammatory patterns were not affected by aSyn deficiency. These data provide further evidence for aSyn as regulator of peripheral immune responses under neuroinflammatory conditions, thereby also modulating degenerative events in late-stage demyelinating disease

    Comprehensive phenotyping revealed transient startle response reduction and histopathological gadolinium localization to perineuronal nets after gadodiamide administration in rats

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    Gadolinium based contrast agents (GBCAs) are widely used in clinical MRI since the mid-1980s. Recently, concerns have been raised that trace amounts of Gadolinium (Gd), detected in brains even long time after GBCA application, may cause yet unrecognized clinical consequences. We therefore assessed the behavioral phenotype, neuro-histopathology, and Gd localization after repeated administration of linear (gadodiamide) or macrocyclic (gadobutrol) GBCA in rats. While most behavioral tests revealed no difference between treatment groups, we observed a transient and reversible decrease of the startle reflex after gadodiamide application. Residual Gd in the lateral cerebellar nucleus was neither associated with a general gene expression pathway deregulation nor with neuronal cell loss, but in gadodiamide-treated rats Gd was associated with the perineuronal net protein aggrecan and segregated to high molecular weight fractions. Our behavioral finding together with Gd distribution and speciation support a substance class difference for Gd presence in the brain after GBCA application
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