8,618 research outputs found

    Risk and Return in Equity and Options Markets.

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    While theory can tell us about the relationship between prices of risk in options and equity markets within the context of a specific model, what we observe in the data rarely fits any single option pricing model with perfect precision. There seems to be little consensus on a single option pricing model with superior performance above all others. The purpose of this thesis is to empirically investigate the risk-return relation in options markets directly, without resorting to the use of option pricing models based upon relative pricing of options in terms of their underlying. Options markets provide a rich cross-section of data with which to study how investors price assets because they vary across firms, strikes and maturity. As a result, options data provides additional and complimentary information beyond the information contained in stocks. Using these facts, in this thesis I empirically investigate the risk-return relationship across stock option, index option and equity markets. In Chapter I of the thesis I empirically show how to use options data to better estimate the cross-sectional price of market-wide volatility risk. I furthermore compare the price of volatility implicit in the cross-section of stock returns with the price implicit in the cross-section of option returns. In the same chapter I exploit the fact that options can be used to study the term structure properties of risk and return by examining the volatility risk and return tradeoff in options of different times to maturity. In Chapter II, based upon the paper "Pricing Kernel Monotonicity and Conditional Information," co-authored with Sophie Shive and Tyler Shumway, I use data on index options and the underlying index to extract estimates of stochastic discount factors. We propose a new method for non-parametrically estimating the stochastic discount factor. Our method improves upon existing methods by aligning information sets available to investors at each time in our sample and taking these into consideration in our estimation scheme. Empirical results suggest that this may be the solution to a well known anomaly in the literature whereby non-parametric estimates of the pricing kernel tend to be non-monotonic in market returns.PhDBusiness AdministrationUniversity of Michigan, Horace H. Rackham School of Graduate Studieshttp://deepblue.lib.umich.edu/bitstream/2027.42/113552/1/linnm_1.pd

    Vaccination with MMR may reduce disease severity in COVID-19 patients

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    We hypothesise that MMR vaccination is possibly a safe, cheap, effective and readily available method to reduce the severity of COVID-19 disease course in health care workers, elderly patients and other people at risk. The evidence is based on relevant literature.  Suggestions for further studies are given

    Prevention of Glaucoma-Induced Retinal Ganglion Cell Loss Using Alpha7 nAChR Agonists

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    In this study, the neuroprotective effect of various nicotinic alpha7 acetylcholine receptor agonists in an in-vivo model of glaucoma using adult Long Evans rats was analyzed. Glaucoma-like conditions were induced in the eyes of Long Evans rats after injection of hypertonic saline into episcleral veins to create scar tissue and increase the animal’s intraocular pressure. This procedure produced significant loss of retinal ganglion cells within one month and was associated with an increase of intraocular pressure. Using this model system, various alpha7 nicotinic acetylcholine receptor (a7 nAChR) agonists were applied at different doses as eye drops to the right eye of adult Long Evans rats while the left eye was left as an internal control. The a7 nAChR agonists used in this study prevented loss of RGCs in a dose dependent manner after the procedure to induce glaucoma-like conditions. PHA-543613 and PNU- 282987 provided the largest degree of RGC survival after inducing glaucomalike conditions, followed by nicotine, SEN 12333, tropisetron, 3-Bromocytisine and DMAB. To provide evidence that neuroprotection of RGCs was mediated through activation of a7 nAChR, in some studies different concentrations of the a7 nAChR antagonist, MLA, was intravitreally injected into experimentally treated eyes before initiation of eye drops and the procedure to induce glaucoma-like conditions. In the presence of MLA, RGC neuroprotection was blocked. Results from these studies suggest that selective a7 nAChR agonists may be used in future therapeutic treatments for glaucoma or other CNS diseases associated with a7 nAChRs

    An Enhanced Tire Model for Dynamic Simulation based on Geometrically Exact Shells

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    In the present work, a tire model is derived based on geometrically exact shells. The discretization is done with the help of isoparametric quadrilateral finite elements. The interpolation is performed with bilinear Lagrangian polynomials for the midsurface as well as for the director field. As time stepping method for the resulting differential algebraic equation a backward differentiation formula is chosen. A multilayer material model for geometrically exact shells is introduced, to describe the anisotropic behavior of the tire material. To handle the interaction with a rigid road surface, a unilateral frictional contact formulation is introduced. Therein a special surface to surface contact element is developed, which rebuilds the shape of the tire

    Polarization measurements on irradiated ammonia

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    The polarization characteristics of ammonia irradiated at liquid helium temperatures and subsequently used in a scattering experiment are discussed.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/87408/2/488_1.pd

    Stability of small amplitude normal modes of a Bose-Einstein condensate with a singly quantized vortex confined in an optical lattice

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    We study the dynamics of a BEC with a singly quantized vortex, placed in the combined potential of a 1-D (2-D) optical lattice and an axi-symmetric harmonic trap. A time-dependent variational Lagrangian analysis shows that an optical lattice helps to stabilize the vortex which in absence of the optical lattice is unstable. We find that the normal modes are stable only if the depth of the optical potential is more than a certain critical value. This critical value of the optical potential depends on the interaction parameter.In general higher the interaction parameter,lower the value of the optical potential required to stabilize the vortex. The BEC with the singly quantized vortex is found to be relatively more unstable in a 2-D optical lattice compared to a 1-D optical lattice.Comment: Revised version with 11 pages including 1 figur

    Ovalbumin sensitization and challenge increases the number of lung cells possessing a mesenchymal stromal cell phenotype

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    Abstract Background Recent studies have indicated the presence of multipotent mesenchymal stromal cells (MSCs) in human lung diseases. Excess airway smooth muscle, myofibroblasts and activated fibroblasts have each been noted in asthma, suggesting that mesenchymal progenitor cells play a role in asthma pathogenesis. We therefore sought to determine whether MSCs are present in the lungs of ovalbumin (OVA)-sensitized and challenged mice, a model of allergic airways disease. Methods Balb/c mice were sensitized and challenged with PBS or OVA over a 25 day period. Flow cytometry as well as colony forming and differentiation potential were used to analyze the emergence of MSCs along with gene expression studies using immunochemical analyses, quantitative polymerase chain reaction (qPCR), and gene expression beadchips. Results A CD45-negative subset of cells expressed Stro-1, Sca-1, CD73 and CD105. Selection for these markers and negative selection against CD45 yielded a population of cells capable of adipogenic, osteogenic and chondrogenic differentiation. Lungs from OVA-treated mice demonstrated a greater average colony forming unit-fibroblast (CFU-F) than control mice. Sorted cells differed from unsorted lung adherent cells, exhibiting a pattern of gene expression nearly identical to bone marrow-derived sorted cells. Finally, cells isolated from the bronchoalveolar lavage of a human asthma patient showed identical patterns of cell surface markers and differentiation potential. Conclusions In summary, allergen sensitization and challenge is accompanied by an increase of MSCs resident in the lungs that may regulate inflammatory and fibrotic responses.http://deepblue.lib.umich.edu/bitstream/2027.42/78265/1/1465-9921-11-127.xmlhttp://deepblue.lib.umich.edu/bitstream/2027.42/78265/2/1465-9921-11-127.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/78265/3/1465-9921-11-127-S1.DOCPeer Reviewe

    Toward a script theory of guidance in computer-supported collaborative learning

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    This article presents an outline of a script theory of guidance for computer-supported collaborative learning (CSCL). With its four types of components of internal and external scripts (play, scene, role, and scriptlet) and seven principles, this theory addresses the question how CSCL practices are shaped by dynamically re-configured internal collaboration scripts of the participating learners. Furthermore, it explains how internal collaboration scripts develop through participation in CSCL practices. It emphasizes the importance of active application of subject matter knowledge in CSCL practices, and it prioritizes transactive over non-transactive forms of knowledge application in order to facilitate learning. Further, the theory explains how external collaboration scripts modify CSCL practices and how they influence the development of internal collaboration scripts. The principles specify an optimal scaffolding level for external collaboration scripts and allow for the formulation of hypotheses about the fading of external collaboration scripts. Finally, the article points towards conceptual challenges and future research questions

    Influence of ocean warming and acidification on trace metal biogeochemistry

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    Rising atmospheric CO2 concentrations will have profound effects on atmospheric and hydrographic processes, which will ultimately modify the supply and chemistry of trace metals in the ocean. In addition to an increase in sea surface temperatures, higher CO2 also results in a decrease of seawater pH, known as ocean acidification, with implications for inorganic trace metal chemistry. Furthermore, direct or indirect effects of ocean acidification and ocean warming on marine biota will also affect trace metal biogeochemistry via alteration of biological trace metal uptake rates and metal binding to organic ligands. Currently, we still lack a holistic understanding of the impacts of decreasing seawater pH and rinsing temperatures on different trace metals and marine biota, which complicates projections into the future. Here, we outline how ocean acidification and ocean warming will influence the inputs and cycling of Fe and other biologically relevant trace metals globally, and regionally in high and low latitudes of the future ocean, discuss uncertainties, and highlight essential future research fields
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