The financial accelerator effect: concept and challenges

This review concentrates on the role of information asymmetry in financial markets in the amplification and propagation of short-run output fluctuations. We find that the financial accelerator effect, as it is known, provides a consistent, first principle based, theoretical framework for the analysis of the relationship between financial markets and short-run output fluctuations. It also provides a plausible explanation of the proximate causes of the recent crisis, and first principle-based theoretical background for the credit policy measures taken during this crisis by many central banks and fiscal authorities. Despite the theoretical plausibility, the empirical evidence about the economic importance of the financial accelerator effect is still relatively weak. We also suggest two new aspects to expand existing concept of the financial accelerator effect, which call for further research.economic forecasting, density forecasting, fan chart, stochastic simulations, uncertainty, Croatia

Investments and capital market imperfections, identification issues: a survey

If financial markets are perfect, the choice of the sources of finance does not influence investment decisions. However, financial markets are considered to be far from perfect. This review concentrates on the role of information asymmetry in determining real investment decisions. Despite the theoretical plausibility of a relationship between capital market imperfections and real investments, the empirical literature has found it difficult to identify this channel. Overall, more research is needed to identify a method that will not be subject to criticisms related to the use of cash-flow in the investment equation and will be based on the data that are relatively available across countries and over time.investment, asymmetric information, capital markets imperfections

Characterization of a novel type of HIV-1 particle assembly inhibitor using a quantitative Luciferase-Vpr packaging-based assay

The HIV-1 auxiliary protein Vpr and Vpr-fusion proteins can be copackaged with Gag precursor (Pr55Gag) into virions or membrane-enveloped virus-like particles (VLP). Taking advantage of this property, we developed a simple and sensitive method to evaluate potential inhibitors of HIV-1 assembly in a living cell system. Two proteins were coexpressed in recombinant baculovirus-infected Sf9 cells, Pr55Gag, which formed the VLP backbone, and luciferase fused to the N-terminus of Vpr (LucVpr). VLP-encapsidated LucVpr retained the enzymatic activity of free luciferase. The levels of luciferase activity present in the pelletable fraction recovered from the culture medium correlated with the amounts of extracellular VLP released by Sf9 cells assayed by conventional immunological methods. Our luciferase-based assay was then applied to the characterization of betulinic acid (BA) derivatives that differed from the leader compound PA-457 (or DSB) by their substituant on carbon-28. The beta-alanine-conjugated and lysine-conjugated DSB could not be evaluated for their antiviral potentials due to their high cytotoxicity, whereas two other compounds with a lesser cytotoxicity, glycine-conjugated and ε-NH-Boc-lysine-conjugated DSB, exerted a dose-dependent negative effect on VLP assembly and budding. A fifth compound with a low cytotoxicity, EP-39 (ethylene diamine-conjugated DSB), showed a novel type of antiviral effect. EP-39 provoked an aberrant assembly of VLP, resulting in nonenveloped, morula-like particles of 100-nm in diameter. Each morula was composed of nanoparticle subunits of 20-nm in diameter, which possibly mimicked transient intermediates of the HIV-1 Gag assembly process. Chemical cross-linking in situ suggested that EP-39 favored the formation or/and persistence of Pr55Gag trimers over other oligomeric species. EP-39 showed a novel type of negative effect on HIV-1 assembly, targeting the Pr55Gag oligomerisation. The biological effect of EP-39 underlined the critical role of the nature of the side chain at position 28 of BA derivatives in their anti-HIV-1 activity

Retinal atrophy in relation to visual functioning and vision-related quality of life in patients with multiple sclerosis

BACKGROUND: Inner retinal layer atrophy in patients with multiple sclerosis (MS) has been validated as a structural imaging biomarker for neurodegeneration. OBJECTIVE: To determine how retinal layer thickness relates to high-contrast visual acuity (HCVA), low-contrast visual acuity (LCVA) and vision-related quality of life (QoL) and to investigate the effect of previous episodes on MS-associated optic neuritis (MSON). METHODS: Spectral-domain optical coherence tomography (SD-OCT) was performed in 267 patients with MS. Images were segmented for the peripapillary retinal nerve fiber layer (pRNFL) and the macular ganglion cell inner plexiform layer (GCIPL). Ophthalmological evaluations included history of MSON, HCVA, LCVA, and vision-related QoL. RESULTS: Independent of MSON, HCVA and LCVA were significantly associated with pRNFL and GCIPL thicknesses. Vision-related QoL was positively associated with pRNFL (β = 0.92, p = 0.06) and GCIPL (β = 0.93, p = 0.02) thicknesses. These associations were independent of MSON. Not only binocular but also monocular atrophy of the inner retinal layers was associated with lower vision-related QoL. CONCLUSION: This study showed that retinal atrophy has a significant impact on visual functioning in patients with MS. OCT may therefore provide useful insight to patients with visual dysfunction, and our findings support including OCT and vision-related QoL measures into optic neuritis treatment trials

Data Mining Algorithms for Traffic Sampling, Estimation and Forecasting

Despite the significant investments over the last few decades to enhance and improve road infrastructure worldwide, the capacity of road networks has not kept pace with the ever increasing growth in demand. As a result, congestion has become endemic to many highways and city streets. As an alternative to costly and sometimes infeasible construction of new roads, transportation departments are increasingly looking at ways to improve traffic flow over the existing infrastructure. The biggest challenge in accomplishing this goal is the ability to sample traffic data, estimate traffic current state, and forecast its future behavior. In this thesis, we first address the problem of traffic sampling where we propose strategies for frugal sensing where we collect a fraction of the observed traffic information to reduce costs while achieving high accuracy. Next we demonstrate how traffic estimation using deterministic traffic models can be improved using proposed data reconstruction techniques. Finally, we propose how mixture of experts algorithm which consists of two regime-specific linear predictors and a decision tree gating function can improve short-term and long-term traffic forecasting. As mobile devices become more pervasive, participatory sensing is becoming an attractive way of collecting large quantities of valuable location-based data. An important participatory sensing application is traffic monitoring, where GPS-enabled smartphones can provide invaluable information about traffic conditions. We propose a strategy for frugal sensing in which the participants send only a fraction of the observed traffic information to reduce costs while achieving high accuracy. The strategy is based on autonomous sensing, in which participants make decisions to send traffic information without guidance from the central server, thus reducing the communication overhead and improving privacy. To provide accurate and computationally efficient estimation of the current traffic, we propose to use a budgeted version of the Gaussian Process model on the server side. The experiments on real-life traffic data sets indicate that the proposed approach can use up to two orders of magnitude less samples than a baseline approach with only a negligible loss in accuracy. The estimation of the state of traffic provides a detailed picture of the conditions of a traffic network based on limited traffic measurements and, as such, plays a key role in intelligent transportation systems. Most often, traffic measurements are aggregated over multiple time steps, and this procedure raises the question of how to best use this information for state estimation. Reconstructing the high-resolution measurements from the aggregated ones and using them to correct the state estimates at every time step are proposed. Several reconstruction techniques from signal processing, including kernel regression and a reconstruction approach based on convex optimization, were considered. Experimental results show that signal reconstruction leads to more accurate traffic state estimation as compared with the standard approach for dealing with aggregated measurements. Accurate traffic speed forecasting can help in trip planning by allowing travelers to avoid congested routes, either by choosing alternative routes or by changing the departure time. An important feature of traffic is that it consists of free flow and congested regimes, which have significantly different properties. Training a single traffic speed predictor for both regimes typically results in suboptimal accuracy. To address this problem, a mixture of experts algorithm which consists of two regime-specific linear predictors and a decision tree gating function was developed. Experimental results showed that mixture of experts approach outperforms several popular benchmark approaches.Computer and Information Scienc

Objective quantification of vitreous haze on optical coherence tomography scans: no evidence for relationship between uveitis and inflammation in multiple sclerosis

BACKGROUND AND PURPOSE: The occurrence of intermediate uveitis, which is characterized by the presence of vitreous haze (VH), in patients with multiple sclerosis (MS) may be a sign of coexistent inflammatory central nervous system (CNS) disease activity. Using an automated algorithm to quantify VH on optical coherence tomography (OCT) scans, the aim was to investigate whether VH in MS patients is associated with signs of inflammatory CNS disease activity. METHODS: Vitreous haze was quantified on OCT macular volume scans of 290 MS patients and 85 healthy controls (HCs). The relationship between VH and clinical, retinal OCT and magnetic resonance imaging parameters of inflammatory disease activity was investigated using generalized estimating equations. RESULTS: Mean VH scores did not differ between patients and HCs (P = 0.629). Six patients (2.1%) showed values higher than the highest of the controls by HCs. VH scores did not differ between the different disease types or between eyes with and without a history of optic neuritis (P = 0.132). VH was not associated with inner nuclear layer volume on OCT (P = 0.233), cerebral T2 lesion load on magnetic resonance imaging (P = 0.416) or the development of new relapses (P = 0.205). CONCLUSION: In this study, OCT-based automated VH estimation did not detect increased vitreous inflammation in MS patients compared to HCs and did not find an association with CNS inflammatory burden

The effect of pore geometry on the mechanical properties of cast aluminium

This thesis delves into the influence of pore geometry on the mechanical characteristics of High Pressure Die Cast (HPDC) aluminum. Additionally, it explores the feasibility of developing a material model capable of capturing the mechanical behavior for various types of porosity. Utilizing X-ray computed tomography Aided Engineering (XAE), pores were integrated into a virtual model, accurately mirroring those observed in the test coupons. These virtual replicas, in conjunction with Representative Volume Element (RVE) models, were employed alongside Finite Element Methods (FEM) to simulate the effects of porosity, including variations in pore shape, volume, and distribution. Significant findings indicate that larger pores and those situated near boundaries substantially diminish both material strength and ductility. An attempt was made to optimize the material model to encompass all findings from the test coupons. However, due to considerable disparities in failure strain among certain coupons, it was concluded that a single material model was inadequate for precise results. Consequently, two distinct material models were devised to address varying porosity volume fractions. The results demonstrate the potential for predicting failure in relation to porosity, with optimized models exhibiting a relatively accurate prediction of similar pore structures, with a maximum relative error of 6 % and 7 %, respectively

Directional Ionic Bonds

Covalent and ionic bonds represent two fundamental forms of bonding between atoms. In contrast to bonds with significant covalent character, ionic bonds are of limited use for the spatial structuring of matter because of the lack of directionality of the electric field around simple ions. We describe a predictable directional orientation of ionic bonds that contain concave nonpolar shields around the charged sites. Such directional ionic bonds offer an alternative to hydrogen bonds and other directional noncovalent interactions for the structuring of organic molecules and materials

Multichannel Marketing - Potenziale des Digitaldrucks in der Unternehmenskommunikation

Diese Diplomarbeit beschäftigt sich mit den Möglichkeiten der Unternehmenskommunikation im heutigen digitalen Zeitalter. Durch die neuen Kommunikationskanäle Internet und Mobilfunk und dem daraus entstandenen veränderten Mediennutzungsverhalten müssen die Unternehmen neue crossmediale Kommunikationsstrategien entwickeln um den Dialog mit dem Kunden aufrechterhalten zu können. Andererseits ergeben sich aber vor allem dadurch viele neue Möglichkeiten sich der Unternehmensumwelt präsentieren zu können und dem Kunden einen umfassenden Service anzubieten