85 research outputs found
Vagus somatosensorisch evozierte Potenziale - Die grundlegende Betrachtung einer potenziellen Methode zur Früherkennung neurodegenerativer Erkrankungen
No full textDie Methode der Vagus somatosensorisch evozierten Potenziale (VSEP) ist eine noch relativ junge Methode, die vielversprechende Ansätze zur tiefergehenden Erforschung und weiteren Entwicklung als potenzielle Methode zur Früherkennung von Neurodegeneration bietet. Bisher wurden zwar sehr interessante und vielversprechende Studien, aber mit geringer Fallzahl zur Methode der VSEP veröffentlicht. Ziel dieser Studie war es, die VSEP erstmalig an einem großen Probandenkollektiv zu erheben, und hinsichtlich allgemeiner, demografischer Aspekte und Einflüsse wie Alter, Geschlecht, Ergebnis in einem Screening-Test für Alzheimer-Demenz und Familienanamnese bezüglich Demenzerkrankungen zu untersuchen. Es wurden für diese Arbeit 1080 VSEP erhoben und ausgewertet
Simulation of near-infrared light absorption considering individual head and prefrontal cortex anatomy: implications for optical neuroimaging
No full textFunctional near-infrared spectroscopy (fNIRS) is an established optical neuroimaging method for measuring functional hemodynamic responses to infer neural activation. However, the impact of individual anatomy on the sensitivity of fNIRS measuring hemodynamics within cortical gray matter is still unknown. By means of Monte Carlo simulations and structural MRI of 23 healthy subjects (mean age: (25.0 +- 2.8 years), we characterized the individual distribution of tissue-specific NIR-light absorption underneath 24 prefrontal fNIRS channels. We, thereby, investigated the impact of scalp-cortex distance (SCD), frontal sinus volume as well as sulcal morphology on gray matter volumes (V gray) traversed by NIR-light, i.e. anatomy-dependent fNIRS sensitivity. The NIR-light absorption between optodes was distributed describing a rotational ellipsoid with a mean penetration depth of (23.6 +- 0.7 mm) considering the deepest 5% of light. Of the detected photon packages scalp and bone absorbed (96.4 +- 9.7)% and absorbed (3,1 +- 1.8)% of the energy. The mean V gray volume (1.1 +- 0.4)cm 3 was negatively correlated (r = -.76) with the SCD and frontal sinus volume (r= -.57) and was reduced by in subjects with relatively large compared to small frontal sinus. Head circumference was significantly positively correlated with the mean SCD (r= .46) and the traversed frontal sinus volume (r= .43). Sulcal morphology had no significant impact on . Our findings suggest to consider individual SCD and frontal sinus volume as anatomical factors impacting fNIRS sensitivity. Head circumference may represent a practical measure to partly control for these sources of error variance
Depreciation and impairment. A tradeoff in a stewardship setting
No full textScholze A, Wielenberg S. Depreciation and impairment. A tradeoff in a stewardship setting. Diskussionspapiere / Fakultät für Wirtschaftswissenschaften, Universität Bielefeld. Bielefeld: Universität Bielefeld; 2007.This paper examines the relationship between depreciation and future impairment losses. This relationship exists, since impairment losses can only be recognized if the carrying amount of an asset exceeds a certain recoverable amount that can be defined in different ways. Sufficiently large depreciation charges in the beginning of the asset's useful life make it very unlikely that an impairment acutally occurs in future periods. In the context of a multi-period agency model with ex ante long-term investment, and ex post short-term effort incentives, we will show that this relationship causes a tradeoff during the useful life of the asset. In order to induce efficient investment decisions, the investment cost has to be allocated over future periods according to a specific depreciation schedule. However, those depreciation charges decrease the likelihood that impairment losses will occur in later periods. Therefore the information content of the performance measure will be decreased as well. We apply our result to impairment tests according to IFRS and US-GAAP, the accounting for goodwill, and accounting rules for similar problems
Einführung in das Kapitalstrukturmanagement
No full textThis paper gives an overview of the capital requirements for banks. Regulatory capital is analyzed, followed by the discussion of economic capital. These ideas are used to explain risk adjusted performance measures. --Regulatorisches Kapital,ökonomisches Kapital,RAROC,RORAC
Pricing Derivatives Under A Gains Tax Regime: New Impacts
No full textWöster C. Pricing Derivatives Under A Gains Tax Regime: New Impacts. Discussion paper / Fakultät für Wirtschaftswissenschaften, Universität Bielefeld. Vol 559. Bielefeld: Universität Bielefeld; 2006.Three years after the seminal work of Black and Scholes on the pricing of European options, Scholes presented a paper in which the impact of taxation on the value of an option is analyzed. We restart this discussion in a simple binomial setting emphasizing the economic principles of replicating strategies under taxation. Two perspectives will be introduced. The first one focuses on replicating payoff structures if the underlying assets are taxed. The second one discusses the influence of a tax system on a given contract specification. The limit results lead to a pricing formula in closed form suggesting a modification of the partial differential equation derived by Scholes. We claim that the value of the option is influenced by taxation even if gains of all relevant assets are taxed with the same rate. Furthermore, we demonstrate that the difference between numerical and closed form solutions are negligible in acceptable computing time. Thus the algorithmic schemes can be used as a base for pricing of complex options under taxation
The impact of taxation on upper and lower bounds of enterprise value
No full textBraun T. The impact of taxation on upper and lower bounds of enterprise value. Discussion paper / Fakultät für Wirtschaftswissenschaften, Universität Bielefeld. Bielefeld: Universität Bielefeld; 2005.This paper derives and draws on simple formulae for the upper and lower bounds to the value of a series of risky cash flows in order to provide some instructive insights in the impact of taxation on these bounds.
The formulae are based on no-arbitrage conditions in a setting that is a straightforward extension of the Cox, Ross, and Rubinstein option-pricing model to an incomplete market model and look exactly like the popular Gordon growth formula.
Although based on stylized facts concerning the tax scheme the results promise to be a reliable guide for further research in this field
A new heuristic for the total tardiness problem with parallel machines
No full textBiskup D, Herrmann J. A new heuristic for the total tardiness problem with parallel machines. Discussion paper / Fakultät für Wirtschaftswissenschaften, Universität Bielefeld. Bielefeld: Universität Bielefeld; 2007.Scheduling jobs against due dates is one of the most important and best examined objectives in scheduling theory and practice. In this paper the parallel machine version of the well-known total tardiness problem is considered. The objective is to minimize the total tardiness of the jobs, while for all jobs an individual due date is given. The single machine version has been proven to be NP-hard, hence it is unlikely to find polynomially bounded optimization algorithms. Consequently, we concentrate on developing an efficient heuristic. Our extensive computational results confirm that our new heuristic is capable to deliver near optimal results
Replication in Consistent Binomial Models
No full textWöster C. Replication in Consistent Binomial Models. Discussion paper / Fakultät für Wirtschaftswissenschaften, Universität Bielefeld. Vol 545. Bielefeld: Universität Bielefeld; 2005.The binomial model has been used to price a wide variety of equity and interest rate options for more than two decades. Originally developed by Cox, Ross, and Rubinstein to clarify the basic pricing principle of its continuous-time counterpart with reduced mathematical requirements, the approach became a numerical scheme to evaluate all kinds of contingent claims. Some of the algorithms have dissociated more and more from the basic principles. In this paper we turn to the foundations of the binomial model and elaborate the relation between real world processes, replicating strategies and martingales in a strict way
Local synchronization of resting-state dynamics encodes Gray's trait Anxiety
No full textThe Behavioral Inhibition System (BIS) as defined within the Reinforcement Sensitivity Theory (RST) modulates reactions to stimuli indicating aversive events. Gray’s trait Anxiety determines the extent to which stimuli activate the BIS. While studies have identified the amygdala-septo-hippocampal circuit as the key-neural substrate of this system in recent years and measures of resting-state dynamics such as randomness and local synchronization of spontaneous BOLD fluctuations have recently been linked to personality traits, the relation between resting-state dynamics and the BIS remains unexplored. In the present study, we thus examined the local synchronization of spontaneous fMRI BOLD fluctuations as measured by Regional Homogeneity (ReHo) in the hippocampus and the amygdala in twenty-seven healthy subjects. Correlation analyses showed that Gray’s trait Anxiety was significantly associated with mean ReHo in both the amygdala and the hippocampus. Specifically, Gray’s trait Anxiety explained 23% and 17% of resting-state ReHo variance in the left amygdala and the left hippocampus, respectively. In summary, we found individual differences in Gray’s trait Anxiety to be associated with ReHo in areas previously associated with BIS functioning. Specifically, higher ReHo in resting-state neural dynamics corresponded to lower sensitivity to punishment scores both in the amygdala and the hippocampus. These findings corroborate and extend recent findings relating resting-state dynamics and personality while providing first evidence linking properties of resting-state fluctuations to Gray’s BIS
Correction to: Severe Dysbiosis and Specific Haemophilus and Neisseria Signatures as Hallmarks of the Oropharyngeal Microbiome in Critically Ill Coronavirus Disease 2019 (COVID-19) Patients
No full textThis is a pre-copyedited, author-produced PDF of an article accepted for publication in Clinical Infectious Diseases following peer review. The version of record, Juliana de Castilhos, PhD, Eli Zamir, PhD, Theresa Hippchen, MD, Roman Rohrbach, Sabine Schmidt, Silvana Hengler, Hanna Schumacher, Melanie Neubauer, Sabrina Kunz, Tonia Müller-Esch, Andreas Hiergeist, PhD, André Gessner, MD PhD, Dina Khalid, MD, Rogier Gaiser, PhD, Nyssa Cullin, PhD, Stamatia M Papagiannarou, Bettina Beuthien-Baumann, MD, Alwin Krämer, MD, Ralf Bartenschlager, PhD, Dirk Jäger, MD, Michael Müller, MD, Felix Herth, MD, Daniel Duerschmied, MD, Jochen Schneider, MD, Roland M Schmid, MD, Johann F Eberhardt, Yascha Khodamoradi, MD, Maria J G T Vehreschild, MD, Andreas Teufel, MD, Matthias P Ebert, MD, Peter Hau, MD, Bernd Salzberger, MD, Paul Schnitzler, PhD, Hendrik Poeck, MD, Eran Elinav, MD PhD, Uta Merle, MD, Christoph K Stein-Thoeringer, MD, Severe dysbiosis and specific Haemophilus and Neisseria signatures as hallmarks of the oropharyngeal microbiome in critically ill COVID-19 patients, Clinical Infectious Diseases, 2021;, ciab902, https://doi.org/10.1093/cid/ciab902, is available online at: https://doi.org/10.1093/cid/ciab902.
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