Social and Behavioral Sciences Commons^™

Optimal Inference For Spot Regressions, Tim Bollerslev, Jia Li, Yuexuan Ren

Research Collection School Of Economics

Betas from return regressions are commonly used to measure systematic financial market risks. "Good" beta measurements are essential for a range of empirical inquiries in finance and macroeconomics. We introduce a novel econometric framework for the nonparametric estimation of time-varying betas with high-frequency data. The "local Gaussian" property of the generic continuous-time benchmark model enables optimal "finite-sample" inference in a well-defined sense. It also affords more reliable inference in empirically realistic settings compared to conventional large-sample approaches. Two applications pertaining to the tracking performance of leveraged ETFs and an intraday event study illustrate the practical usefulness of the new procedures.

Systematic And Idiosyncratic Risks Of The U.S. Airline Industry, Rafiqul Bhuyan, André Varella Mollick, Md Ruhul Amin

Economics and Finance Faculty Publications and Presentations

Understanding the risky nature of the airline industry has received attention in the tourism literature from separate angles. Although the systematic risk of the airline industry has been examined before, idiosyncratic risk has largely been ignored. This study fills this gap in the tourism literature by investigating the effect of passengers’ air travel on systematic and idiosyncratic risks of the U.S. airline industry. Using historical air travel data and utilizing both OLS and fixed-effect models, this paper documents negative relationships between the occupancy of airline seats and idiosyncratic risks for 21 U.S. airline companies. This negative effect of occupancy is …

Variation And Efficiency Of High-Frequency Betas, Congshan Zhang, Jia Li, Viktor Todorov, George Tauchen

Research Collection School Of Economics

This paper studies the efficient estimation of betas from high-frequency return data on a fixed time interval. Under an assumption of equal diffusive and jump betas, we derive the semiparametric efficiency bound for estimating the common beta and develop an adaptive estimator that attains the efficiency bound. We further propose a Hausman type test for deciding whether the common beta assumption is true from the high-frequency data. In our empirical analysis we provide examples of stocks and time periods for which a common market beta assumption appears true and ones for which this is not the case. We further quantify …

Increased Beta Activity Links To Impaired Emotional Control In Adhd Adults With High Iq, Hui Li, Qihua Zhao, Fang Huang, Qingjiu Cao, Stuart J. Johnstone, Yufeng Wang, Changming Wang, Li Sun

Faculty of Social Sciences - Papers (Archive)

Objective: The present study investigated the neuropathology of everyday-life executive function (EF) deficits in adults with ADHD with high IQ. Method: Forty adults with ADHD with an IQ ≥ 120 and 40 controls were recruited. Ecological EFs were measured, and eyes-closed Electroencephalograph (EEG) signals were recorded during a resting-state condition; EEG power and correlations with impaired EFs were analyzed. Results: Compared with controls, the ADHD group showed higher scores on all clusters of EF. The ADHD group showed globally increased theta, globally decreased alpha, and increased central beta activity. In the ADHD group, central beta power was significantly related to …

Adaptive Estimation Of Continuous-Time Regression Models Using High-Frequency Data, Jia Li, Viktor Todorov, George Tauchen

Research Collection School Of Economics

We derive the asymptotic efficiency bound for regular estimates of the slope coefficient in a linear continuous-time regression model for the continuous martingale parts of two Itô semimartingales observed on a fixed time interval with asymptotically shrinking mesh of the observation grid. We further construct an estimator from high-frequency data that achieves this efficiency bound and, indeed, is adaptive to the presence of infinite-dimensional nuisance components. The estimator is formed by taking optimal weighted average of local nonparametric volatility estimates that are constructed over blocks of high-frequency observations. The asymptotic efficiency bound is derived under a Markov assumption for the …

Indirect Radio-Chemo-Beta Therapy: A Targeted Approach To Increase Biological Efficiency Of X-Rays Based On Energy, Sianne Oktaria, Stephanie Corde, Michael L. F Lerch, Konstantin K. Konstantinov, Anatoly B. Rosenfeld, Moeava Tehei

Faculty of Engineering and Information Sciences - Papers: Part A

Despite the use of multimodal treatments incorporating surgery, chemotherapy and radiotherapy, local control of gliomas remains a major challenge. The potential of a new treatment approach called indirect radio-chemo-beta therapy using the synergy created by combining methotrexate (MTX) with bromodeoxyuridine (BrUdR) under optimum energy x-ray irradiation is assessed. 9L rat gliosarcoma cells pre-treated with 0.01 μM MTX and/or 10 μM BrUdR were irradiated in vitro with 50 kVp, 125 kVp, 250 kVp, 6 MV and 10 MV x-rays. The cytotoxicity was assessed using clonogenic survival as the radiobiological endpoint. The photon energy with maximum effect was determined using radiation sensitization …

Prestimulus Alpha And Beta Determinants Of Erp Responses In The Go/Nogo Task, Frances M. De Blasio, Robert Barry

Faculty of Social Sciences - Papers (Archive)

The nature of the relationships between the level of immediately-prestimulus EEG activity and auditory ERP components remains unclear. Particularly, both inverse and direct relationships have been reported for the alpha band. Here we aim to clarify the pattern of prestimulus EEG contributions in alpha (8-13 Hz), and investigate those in beta (14-24 Hz), for five ERP components (P1, N1, P2, N2, P3) in an auditory equiprobable Go/NoGo paradigm. Separate FFTs were applied to the prestimulus Cz data of each accepted trial. The alpha and beta bands were independently assessed. The mean prestimulus spectral band amplitude was computed and used to …

Wild Type And Tangier Disease Abca1 Mutants Modulate Cellular Amyloid-Beta Production Independent Of Cholesterol Efflux Activity, Kim S. Woojin, Andrew F. Hill, Michael L. Fitzgerald, Mason W. Freeman, Genevieve Evin, Brett Garner

Faculty of Science - Papers (Archive)

Cerebral amyloid-β (Aβ) deposition is a critical feature of Alzheimer’s disease. Aβ is derived from the amyloid-β protein precursor (AβPP) via two sequential cleavages that are mediated by β-secretase and the γ-secretase complex. Such amyloidogenic AβPP processing occurs in lipid raft microdomains of cell membranes and it is thought that modulating the distribution of lipids in rafts may regulate AβPP processing and Aβ production. Certain ATP-binding cassette (ABC) transporters regulate lipid transport across cell membranes and, as recent studies reveal, within membrane microdomains. ABCA1 also regulates Aβ metabolism in the brain although its direct impact on AβPP remains an open …

Zach's News, Georgia Southern University, Zach S. Henderson Library

University Libraries News Online (2008-2023)

• The RefWorks 2.0 Beta Interface is now available at GSU

Dipyridyl Beta-Diketonate Complexes: Versatile Polydentate Metalloligands For Metal-Organic Frameworks And Hydrogen-Bonded Networks, Andrew D. Burrows, Christopher G. Frost, Mary F. Mahon, Paul R. Raithby, Catherine L. Renouf, Christopher Richardson, Anna J. Stevenson

Faculty of Science - Papers (Archive)

The Group 13 metal complexes [M(L-2)(3)], where M is Al or Ga and L-2 is 1,3-di(4-pyridyl)-1,3-propanedionato, are hexatopic metalloligands that have been used to prepare mixed-metalorganic frameworks containing interpenetrated primitive cubic networks. In contrast, the europium complex [Eu(HL2)(3)-(H2L2)]Cl-4 center dot EtOH forms a hydrogen-bonded network following partial protonation of the pyridyl groups.

Extracellular Chaperones Modulate The Effects Of Alzheimer's Patient Cerebrospinal Fluid On A Beta(1-42) Toxicity And Uptake , Justin J. Yerbury, Mark R. Wilson

Faculty of Science - Papers (Archive)

Alzheimer's disease is characterised by the inappropriate death of brain cells and accumulation of the A beta peptide in the brain. Thus, it is possible that there are fundamental differences between Alzheimer's disease patients and healthy individuals in their abilities to clear A beta from brain fluid and to protect neurons from A beta toxicity. In the present study, we examined (1) the cytotoxicity of Alzheimer's disease cerebrospinal fluid (CSF) compared to control CSF, (2) the ability of Alzheimer's disease and control CSF to protect cells from A beta toxicity and to promote cell-mediated clearance of A beta and lastly …

Alphab-Crystallin Inhibits The Cell Toxicity Associated With Amyloid Fibril Formation By Kappa-Casein And The Amyloid-Beta Peptide, Francis C. Dehle, Heath Ecroyd, Ian F. Musgrave, John A. Carver

Faculty of Science - Papers (Archive)

Amyloid fibril formation is associated with diseases such as Alzheimer’s, Parkinson’s, and prion diseases. Inhibition of amyloid fibril formation by molecular chaperone proteins, such as the small heat-shock protein αB-crystallin, may play a protective role in preventing the toxicity associated with this form of protein misfolding. Reduced and carboxymethylated κ-casein (RCMκ-CN), a protein derived from milk, readily and reproducibly forms fibrils at physiological temperature and pH. We investigated the toxicity of fibril formation by RCMκ-CN using neuronal model PC12 cells and determined whether the inhibition of fibril formation altered its cell toxicity. To resolve ambiguities in the literature, we also …

Beta-Glucans In The Treatment Of Diabetes And Associated Cardiovascular Risks, Jiezhong Chen, Kenneth Raymond

Faculty of Social Sciences - Papers (Archive)

Diabetes mellitus is characterized by high blood glucose level with typical manifestations of thirst, polyuria, polydipsia, and weight loss. It is caused by defects in insulin-mediated signal pathways, resulting in decreased glucose transportation from blood into muscle and fat cells. The major risk is vascular injury leading to heart disease, which is accelerated by increased lipid levels and hypertension. Management of diabetes includes: control of blood glucose level and lipids; and reduction of hypertension. Dietary intake of beta-glucans has been shown to reduce all these risk factors to benefit the treatment of diabetes and associated complications. In addition, beta-glucans also …

Crystallization And Diffraction Data Of 1h-3-Hydroxy-4-Oxoquinoline 2,4-Dioxygenase: A Cofactor-Free Oxygenase Of The Alpha/Beta-Hydrolase Family, Ruhu Qi, Susanne Fetzner, Aaron J. Oakley

Faculty of Science - Papers (Archive)

1H-3-Hydroxy-4-oxoquinoline 2,4-dioxygenase (QDO) from Pseudomonas putida 33/1 catalyses the oxygenolysis of 1H-3-hydroxy-4-oxoquinoline to form N-formylanthranilic acid and carbon monoxide without the aid of cofactors. Both N-terminally His6-tagged and native QDO were overexpressed in Escherichia coli and purified by conventional chromatographic procedures. Untagged QDO, but not His6-tagged QDO, was crystallized by the vapour-diffusion method, giving hexagonal bipyramid crystals belonging to space group P6(1)22. Selenomethionine-containing native QDO was prepared and crystallized under identical conditions. The unit-cell parameters were a = b = 90.1, c = 168.6 A, alpha = beta = 90, gamma = 120 degrees. Using synchrotron radiation, these crystals diffract …

Beta-Utopian Order, Teodor E. Mitew

Faculty of Arts - Papers (Archive)

In one of its most popular works – Electronic Civil Disobedience and Other Unpopular Ideas, the Critical Art Ensemble (CAE) outlines what it views as a major power shift characterizing the present, namely, the traditional public space – the street, has turned into ‘dead capital’. Borrowing from Guy Debord’s ideas on spectacular society, CAE theorizes that the spectacle has appropriated all, while power has mutated into a nomadic form of pure absence – ‘power itself cannot be seen; only its representation appears.’

Beta-2 Glycoprotein I And Its Role In Antiphospholipid Syndrome: Lessons From Knockout Mice, Spyridon Miyakis, Sarah A. Robertson, S A. Krilis

Faculty of Science, Medicine and Health - Papers: part A

The antiphospholipid syndrome is characterized by the presence in serum of autoantibodies against h2GPI. Although the role of h2GPI in the pathogenesis of antiphospholipid antibody syndrome (APS) is well recognized, its exact physiological functions still remain undisclosed. Several interactions of h2GPI with components of the coagulation cascade have been proposed, resulting in both procoagulant and anticoagulant effects. Additionally, h2GPI has been implicated in the mechanism of recurrent fetal loss entailed in APS. Recently, using a homologous recombination approach, reproduction of mice homozygous for deletion of the b2GPI gene has been feasible. h2GPI knockout mice offer a valuable tool for revealing …

Beta-2 Glycoprotein1: Function In Health And Disease, Spyridon Miyakis, Bill Giannakopoulos, S A. Krilis

Faculty of Science, Medicine and Health - Papers: part A

Beta-2 glycoprotein I (β2GPI) is the principal target of autoantibodies in the antiphospholipid syndrome (APS). It is abundant in human plasma and shares high homology between different mammalian species. Although the exact physiological function of β2GPI has not been fully elucidated, several interactions have been described with other proteins and with negatively charged surfaces, such as anionic phospholipids, dextran and heparin. β2GPI is involved in the coagulation pathway, exerting both procoagulant and anticoagulant activities. Plasma from β2GPI-deficient mice exhibits impaired thrombin generation in vitro. Recently, it has been demonstrated that β2GPI binds factor (F) XI in vitro at concentrations lower …

Fgf-2 Counteracts Loss Of Tgfβ Affected Cells From Rat Lens Explants: Implications For Pco (After Cataract), Kylie Mansfield, Anna Cerra, Coral Chamberlain

Faculty of Science, Medicine and Health - Papers: part A

Purpose: While cataract surgery initially benefits most patients, many suffer secondary loss of vision because of posterior capsule opacification (PCO). Lens epithelial cells left behind at surgery become aberrant and migrate into the light path. TGF-beta (TGFβ) appears to play a key role in this process by inducing the cells to undergo an epithelial-mesenchymal transition. Paradoxically, it also typically induces them to undergo apoptotic death. The present study was undertaken to investigate the hypothesis that FGF plays a role in PCO formation by promoting the survival of abnormal cells with PCO-like characteristics.

Methods: Rat lens epithelial explants were cultured for …

Exacerbation Of Tgf-Β-Induced Cataract By Fgf-2 In Cultured Rat Lenses, Anna Cerra, Kylie Mansfield, Coral Chamberlain

Faculty of Social Sciences - Papers (Archive)

Purpose: Culturing rat lenses with transforming growth factor-beta (TGFβ) results in the formation of anterior, opaque subcapsular plaques which exhibit many of the features of human subcapsular cataract. The present study was undertaken to determine whether this process is influenced by the presence of fibroblast growth factor (FGF), a normal component of the lens environment in situ.

Methods: Rat lenses were cultured for 4-8 days with TGFβ-2, alone or in combination with FGF-2, PDGF-AA, or the growth factor inhibitors poly(4-styrenesulfonic acid) (PSS) and suramin. Responses were assessed by monitoring opacification, by routine histology and immunolocalization of markers for fibrotic change …

Decreased Heat Stability And Increased Chaperone Requirement Of Modified Human Βb1-Crystallins, Kirsten J Lampi, Yung H. Kim, Hans Peter Bachinger, Bruce A. Boswell, Robyn A. Lindner, John A. Carver, Thomas R Shearer, Larry L. David, Deborah M. Kapfer

Faculty of Science, Medicine and Health - Papers: part A

Purpose: To determine how deamidation and partial loss of the N- and C-terminal extensions alter the heat stability of βB1-crystallin.

Methods: Human lens βB1, a deamidated βB1, Q204E, and αA-crystallins were expressed. Truncated βB1 was generated by proteolytic removal of part of its terminal extensions. The aggregation and precipitation of these proteins due to heating was monitored by circular dichroism and light scattering. The effect of heat on the stability of both monomers and oligomers was investigated. The flexibility of the extensions in wild type and deamidated βB1 was assessed by ¹H NMR spectroscopy.

Results: With heat, deamidated βB1 …