4,292 research outputs found

    Financial Market Risk and Macroeconomic Stability Variables: Dynamic Interactions and Feedback Effects

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    This study investigates dynamic interactions and feedback effects between financial market risk proxied by VIX and key macroeconomic stability variables that include the rate of unemployment, headline inflation and market-based inflation expectations reflected by the breakeven inflation. I argue that market risk should play a stronger role in macroeconomic modeling and forecasting than it has been recognized thus far in the literature. I employ vector autoregression with impulse response functions, as well as two-state Markov switching tests to examine these interactions on the longest available US monthly data. The empirical tests show that the association between market risk and macroeconomic fundamentals is predominantly neutral at normal, predictable economic conditions. It becomes however very pronounced at times of financial distress, in the environment of elevated market risk coupled with uncertain expectations for macroeconomic variables. Shocks in VIX have a longer impact on macroeconomic stability than that generally claimed in the prior literature. The Markov switching tests for CPI and breakeven inflation indicate that households and businesses are concerned primarily about episodes of increasing inflation, while bond market participants are worried mainly about declining inflation and deflation

    Sign problems, noise, and chiral symmetry breaking in a QCD-like theory

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    The Nambu-Jona-Lasinio model reduced to 2+1 dimensions has two different path integral formulations: at finite chemical potential one formulation has a severe sign problem similar to that found in QCD, while the other does not. At large N, where N is the number of flavors, one can compute the probability distributions of fermion correlators analytically in both formulations. In the former case one finds a broad distribution with small mean; in the latter one finds a heavy tailed positive distribution amenable to the cumulant expansion techniques developed in earlier work. We speculate on the implications of this model for QCD.Comment: 16 pages, 5 figures; Published version with minor changes from the origina

    Montmorilonit – usporedba metoda za njegovo određivanje u ljevaoničkim bentonitima

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    A comparison and estimation of usefulness of a quantitative analysis of montmorillonite in foundry bentonites, was the aim of this research. The investigations were made by means of three different techniques: methylene blue (MB) adsorption method, Cu(II)-triethylenetetramine complex (Cu(II)-TET) adsorption method, and infrared spectroscopy (FTIR) method. Tests were performed for 9 kinds of bentonites originated from various producers. The achieved results indicated that, the results obtained by the FTIR method were, in general, even 10% lower than the ones obtained by other methods. The best correlation with the data given by the producers were obtained for the Cu(II)-TET method. In addition, this method was characterised by the smallest value of standard deviations. A very essential advantage of the Cu(II)-TET method is a much shorter time needed for the analysis and its easier execution, which is important under production conditions.Cilj ovog istraživanja je bila procjena upotrebljivosti kvantitativne analize montmorilonita u ljevaoničkim bentonitima. Istraživanja su provedena pomoću tri različite tehnike: adsorpcija metilenskog modrila (MB), adsorpcija Cu(II)-trietilentetramin kompleksa (CU(II)-TET), i infracrvena spektroskopija (FTIR). Ispitivanja su provedena na 9 vrsta bentonita koji potječu od različitih proizvođača. Rezultati dobiveni FTIR metodom u prosjeku su za čak 10,0% niži od rezultata dobivenih ostalim metodama. Najbolja korelacija s podatcima od proizvođača dobivena je primjenom Cu(II)-TET metode. Osim toga, kod te metode najmanje su vrijednosti standardnih devijacija. Vrlo važna prednost Cu(II)-TET metode je znatno kraće vrijeme potrebno za anaalizu i lakše provođenje, što je značajno u proizvodnim uvjetima

    Gravitational Wave Backgrounds from Colliding ECOs

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    Long baseline atom interferometers offer an exciting opportunity to explore mid-frequency gravitational waves. In this work we survey the landscape of possible contributions to the total 'gravitational wave background' in this frequency band and advocate for targeting this observable. Such an approach is complimentary to searches for resolved mergers from individual sources and may have much to reveal about the Universe. We find that the inspiral phases of stellar-mass compact binaries cumulatively produce a signal well within reach of the proposed AION-km and AEDGE experiments. Hypothetical populations of dark sector exotic compact objects, harbouring just a tiny fraction of the dark energy density, could also generate signatures unique to mid- and low-frequency gravitational wave detectors, providing a novel means to probe complexity in the dark sector.Comment: 32 pages, 5 figure

    Surface excitonic emission and quenching effects in ZnO nanowire/nanowall systems: limiting effects on device potential.

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    We report ZnO nanowire/nanowall growth using a two-step vapour phase transport method on a-plane sapphire. X-ray diffraction and scanning electron microscopy data establish that the nanostructures are vertically well-aligned with c-axis normal to the substrate, and have a very low rocking curve width. Photoluminescence data at low temperatures demonstrate the exceptionally high optical quality of these structures, with intense emission and narrow bound exciton linewidths. We observe a high energy excitonic emission at low temperatures close to the band-edge which we assign to the surface exciton in ZnO at ~ 3.366 eV, the first time this feature has been reported in ZnO nanorod systems. This assignment is consistent with the large surface to volume ratio of the nanowire systems and indicates that this large ratio has a significant effect on the luminescence even at low temperatures. The band-edge intensity decays rapidly with increasing temperature compared to bulk single crystal material, indicating a strong temperature-activated non-radiative mechanism peculiar to the nanostructures. No evidence is seen of the free exciton emission due to exciton delocalisation in the nanostructures with increased temperature, unlike the behaviour in bulk material. The use of such nanostructures in room temperature optoelectronic devices appears to be dependent on the control or elimination of such surface effects

    In vitro tissue microarrays for quick and efficient spheroid characterisation

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    Three-dimensional in vitro microphysiological cultures, such as spheroids and organoids, promise increased patient relevance and therapeutic predictivity compared to reductionist cell monolayers. However, high-throughput characterisation techniques for 3D models are currently limited to simplistic live/dead assays. By sectioning and staining in vitro microtissues researchers can examine their structure, detect DNA, RNA and protein targets and visualise them at the level of single cells. The morphological examination and immunochemistry staining for in vitro cultures has historically been done in a laborious manner involving testing one set of cultures at a time. We have developed a technology to rapidly screen spheroid phenotype and protein expression by arranging 66 spheroids in a gel array for paraffin-embedding, sectioning and immunohistochemsitry. The process is quick, mostly automatable and uses 11 times less reagents compared to conventional techniques. Here we showcase the capabilities of the technique in an array made up of 11 different cell lines stained in conventional H&E staining, as well as immunohistochemistry staining for estrogen (ER), progesterone (PR) human epidermal growth factor receptors (Her-2) and TP53. This new methodology can be used in optimising stem cell-based models of disease and development, for tissue engineering, safety screening and for efficacy screens in cancer research
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