16 Works

On Portfolio Separation Theorems with Heterogeneous Beliefs and Attitudes towards Risk

Fousseni Chabi-Yo, Eric Ghysels & Eric Renault
The early work of Tobin (1958) showed that portfolio allocation decisions can be reduced to a two stage process: first decide the relative allocation of assets across the risky assets, and second decide how to divide total wealth between the risky assets and the safe asset. This so called twofund separation relies on special assumptions on either returns or preferences. Tobin (1958) analyzed portfolio demand in a mean-variance setting. We revisit the fund separation in...

Faculty Engaged Scholarship: Setting Standards and Building Conceptual Clarity

Lynn Blanchard & Andrew Furco

Who are we now? A demographic assessment of the evolution societies

Daniel Matute & Rushworth Catherine
Scientific societies have the potential to catalyze support for communities that have been historically excluded from science. Many of these societies have formed committees to propose and administer initiatives to promote the career and well-being of their members, with a special emphasis on racial and ethnic minorities. Yet, these societies are rarely armed with data to inform their proposals. Three of the evolution societies (American Society of Naturalists, "ASN"; Society of Systematic Biologists, "SSB"; Society...

Loss of Obstetric Services in Rural Appalachia

Caroline Efird, David Dry & Rachel F. Seidman
Background: As rural hospitals across the United States increasingly downsize or close, the availability of inpatient obstetric services continues to decline in rural areas. In rural Appalachia, the termination of obstetric services threatens to exacerbate the existing risk of adverse birth outcomes for women and infants, yet less is known about how the cessation of these services affects the broader community. Purpose: The purpose of this paper is to explain how the loss of local...

Responses of Manduca sexta larvae to heat waves

Joel Kingsolver, Joel Kingsolver, Megan Elizabeth Moore, Kate E. Augustine & Christina A Hill
Climate change is increasing the frequency of heat waves and other extreme weather events experienced by organisms. How does the number and developmental timing of heat waves affect survival, growth and development of insects? Do heat waves early in development alter performance later in development? We addressed these questions using experimental heat waves with larvae of the Tobacco Hornworm, Manduca sexta. The experiments used diurnally fluctuating temperature treatments differing in the number (0-3) and developmental...

Data and code for analysis of effects of climate change on kangaskhan and summary of simulations from Warren et al. 2020

Dan Warren, Alex Dornburg, Katerina Zapfe & Teresa Iglesias
Species distribution models (SDMs) are frequently used to predict the effects of climate change on species of conservation concern. Biases inherent in the process of constructing SDMs and transferring them to new climate scenarios may result in undesirable conservation outcomes. We explore these issues and demonstrate new methods to estimate biases induced by the design of SDM studies. We present these methods in the context of estimating the effects of climate change on Australia’s only...

G-Quadruplex Structure Improves the Immunostimulatory Effects of CpG Oligonucleotides

Kazuaki Hoshi, TOMOHIKO YAMAZAKI, Yuuki Sugiyama, Kaori Tsukakoshi, Wakako Tsugawa, Koji Sode & Kazunori Ikebukuro
Single-strand oligodeoxynucleotides (ODNs) containing unmethylated cytosine-phosphate-guanine (CpG) are recognized by the toll-like receptor 9, a component of the innate immunity. Therefore, they could act as immunotherapeutic agents. Chemically modified CpG ODNs containing a phosphorothioate backbone instead of phosphodiester (PD) were developed as immunotherapeutic agents resistant to nuclease degradation. However, they cause adverse side effects, and so there is a necessity to generate novel CpG ODNs. In the present study, we designed a nuclease-resistant nonmodified CpG...

Data from: Developmental timing of extreme temperature events (heat waves) disrupts host-parasitoid interactions

M. Elizabeth Moore, Joel Kingsolver & Christina Hill
When thermal tolerances differ between interacting species, extreme temperature events (heat waves) will alter the ecological outcomes. The parasitoid wasp Cotesia congregata suffers high mortality when reared throughout development at temperatures that are non-stressful for its host, Manduca sexta. However, the effects of short-term heat stress during parasitoid development are unknown in this host-parasitoid system. Here, we investigate how duration of exposure, daily maximum temperature, and the developmental timing of heat waves impact the performance...

Transparent soil microcosms for live-cell imaging and non-destructive stable isotope probing of soil microorganisms

Elizabeth Shank, Kriti Sharma, Marton Palatinszky, Georgi Nikolov & David Berry
Microscale processes are critically important to soil ecology and biogeochemistry yet are difficult to study due to soil’s opacity and complexity. To advance the study of soil processes, we constructed transparent soil microcosms that enable the visualization of microbes via fluorescence microscopy and the non-destructive measurement of microbial activity and carbon uptake in situ via Raman microspectroscopy. We assessed the polymer Nafion and the crystal cryolite as optically transparent soil substrates. We demonstrated that both...

Langa 18-39y Diet Survey: Taxed and Untaxed Beverages Replication Dataset

Michael Essman

Data from: Diabetes mellitus, glycemic traits, and cerebrovascular disease: A Mendelian randomization study

Marios Georgakis, Eric Harshfield, Rainer Malik, Nora Franceschini, Claudia Langenberg, Nicholas Wareham, Hugh Markus & Martin Dichgans
Objective: We employed Mendelian randomization (MR) to explore the effects of genetic predisposition to type 2 diabetes (T2D), hyperglycemia, insulin resistance, and β-cell dysfunction on risk of stroke subtypes and related cerebrovascular phenotypes. Methods: We selected instruments for genetic predisposition to T2D (74,124 cases, 824,006 controls), HbA1c levels (n=421,923), fasting glucose levels (n=133,010), insulin resistance (n=108,557), and β-cell dysfunction (n=16,378) based on published genome-wide association studies. Applying two-sample MR, we examined associations with ischemic stroke...

Pure species discriminate against hybrids in the Drosophila melanogaster species subgroup

Academic Matute, Antonio Serrato-Capuchina, Timothy D. Schwochert, Stephania Zhang, Baylee Marie Roy, David Peede, Caleigh Koppelman & Daniel Ricardo Matute
Introgression, the exchange of alleles between species, is a common event in nature. This transfer of alleles between species must happen through fertile hybrids. Characterizing the traits that cause defects in hybrids illuminate how and when gene flow is expected to occur. Inviability and sterility are extreme examples of fitness reductions but are not the only type of defects in hybrids. Some traits specific to hybrids are more subtle but are important to determine their...

Biophysical properties governing septin assembly

Benjamin Woods, Ian Seim, Jessica Liu, Grace McLaughlin & Amy Gladfelter
Septin filaments build structures such as rings, lattices and gauzes that serve as platforms for localizing signaling and organizing cell membranes. How cells control the geometry of septin assemblies in poorly understood. We show here that septins are isodesmic polymers, in contrast to cooperative polymerization exhibited by F-actin and microtubules. We constructed a physical model to analyze and interpret how septin assemblies change in the presence of regulators in yeast extracts. Notably filaments differ in...

Supplement to: Global impact of the COVID-19 pandemic on stroke care and intravenous thrombolysis

Raul Nogueira, Muhammed Qureshi, Mohamad Abdalkader, Sheila Martins, Hiroshi Yamagami, Zhongming Qiu, Ossama Mansour, Anvitha Sathya, Anna Czlonkowska, Georgios Tsivgoulis, Diana Aguiar De Sousa, Jelle Demeestere, Robert Mikulik, Peter Vanacker, James Siegler, Janika Korv, Jose Biller, Conrad Liang, Navdeep Sangha, Alicia Zha, Alexandra Czap, Christine Holmstedt, Tanya Turan, George Ntaios, Konark Malhotra … & Thanh Nguyen
Objective: The objectives of this study were to measure the global impact of the pandemic on the volumes for intravenous thrombolysis (IVT), IVT transfers, and stroke hospitalizations over 4 months at the height of the pandemic (March 1 to June 30, 2020) compared with two control 4-month periods. Methods: We conducted a cross-sectional, observational, retrospective study across 6 continents, 70 countries, and 457 stroke centers. Diagnoses were identified by their ICD-10 codes and/or classifications in...

The genetic architecture and evolution of life history divergence among perennials in the Mimulus guttatus species complex

Jennifer Coughlan, Maya Wilson Brown & John Willis
Ecological divergence is a main source of trait divergence between closely related species. Despite its importance in generating phenotypic diversity, the genetic architecture of most ecologically relevant traits is poorly understood. Differences in elevation can impose substantial selection for phenotypic divergence of both complex, correlated suites of traits (such as life history), as well as novel adaptations. Here, we use the Mimulus guttatus species complex to assess if divergence in elevation is accompanied by trait...

Implications of Asymmetry Risk for Portfolio Analysis and Asset Pricing

Fousseni Chabi-Yo, Dietmar Leisen & Eric Renault
Asymmetric shocks are common in markets; securities' payoffs are not normally distributed and exhibit skewness. This paper studies the portfolio holdings of heterogeneous agents with preferences over mean, variance and skewness, and derives equilibrium prices. A three funds separation theorem holds, adding a skewness portfolio to the market portfolio; the pricing kernel depends linearly only on the market return and its squared value. Our analysis extends Harvey and Siddique's (2000) conditional mean-variance-skewness asset pricing model...

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Affiliations

  • University of North Carolina at Chapel Hill
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  • Emory University School of Medicine
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  • New York University Langone Medical Center
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