On the Interactions between Capital Structure and Product Markets.A Survey of the Literature

This paper surveys capital structure theories based on product characteristics and the structure of input and output markets. In this manner, it extends the work of Harris and Raviv (1991). Simultaneously, we relate capital structure to decisions in the input and output markets, such as production and pricing, investments, and entry and exit. We briefly discuss each of the central papers in these literatures and relate them to the other models. Next, we present the known empirical evidence that either supports or rejects these models. Finally, we offer our conclusions and elaborate on this review article’s implications for future research.

Pigeons home faster through polluted air.

Air pollution, especially haze pollution, is creating health issues for both humans and other animals. However, remarkably little is known about how animals behaviourally respond to air pollution. We used multiple linear regression to analyse 415 pigeon races in the North China Plain, an area with considerable air pollution, and found that while the proportion of pigeons successfully homed was not influenced by air pollution, pigeons homed faster when the air was especially polluted. Our results may be explained by an enhanced homing motivation and possibly an enriched olfactory environment that facilitates homing. Our study provides a unique example of animals' response to haze pollution; future studies are needed to identify proposed mechanisms underlying this effect

From Prestellar to Protostellar Cores II. Time Dependence and Deuterium Fractionation

We investigate the molecular evolution and D/H abundance ratios that develop as star formation proceeds from a dense-cloud core to a protostellar core, by solving a gas-grain reaction network applied to a 1-D radiative hydrodynamic model with infalling fluid parcels. Spatial distributions of gas and ice-mantle species are calculated at the first-core stage, and at times after the birth of a protostar. Gas-phase methanol and methane are more abundant than CO at radii $r\lesssim 100$ AU in the first-core stage, but gradually decrease with time, while abundances of larger organic species increase. The warm-up phase, when complex organic molecules are efficiently formed, is longer-lived for those fluid parcels in-falling at later stages. The formation of unsaturated carbon chains (warm carbon-chain chemistry) is also more effective in later stages; C$^+$, which reacts with CH$_4$ to form carbon chains, increases in abundance as the envelope density decreases. The large organic molecules and carbon chains are strongly deuterated, mainly due to high D/H ratios in the parent molecules, determined in the cold phase. We also extend our model to simulate simply the chemistry in circumstellar disks, by suspending the 1-D infall of a fluid parcel at constant disk radii. The species CH$_3$OCH$_3$ and HCOOCH$_3$ increase in abundance in $10^4-10^5$ yr at the fixed warm temperature; both also have high D/H ratios.Comment: accepted to ApJ. 55 pages, 7 figures, 3 table

The actual impedance of non-reflecting boundary conditions : implications for the computation of resonators

Non-reflecting boundary conditions are essential elements in the computation of many compressible flows: such simulations are very sensitive to the treatment of acoustic waves at boundaries. Non-reflecting conditions allow acoustic waves to propagate through boundaries with zero or small levels of reflection into the domain. However, perfectly non-reflecting conditions must be avoided because they can lead to ill-posed problems for the mean flow. Various methods have been proposed to construct boundary conditions which can be sufficiently non-reflecting for the acoustic field while still making the mean-flow problem well posed. This paper analyses a widely-used technique for non-reflecting outlets (Rudy and Strikwerda, Poinsot and Lele). It shows that the correction introduced by these authors can lead to large reflection levels and non-physical resonant behaviors. A simple scaling is proposed to evaluate the relaxation coefficient used in theses methods for a non-reflecting outlet. The proposed scaling is tested for simple cases (ducts) both theoretically and numerically

Are We Listening to Our Limited-resource Audiences? Engaging Parents and Caregivers with Nutrition Messaging in Extension Programs

Social marketing campaigns can be an effective method for reaching and engaging limited-resource participants in health messages related to nutrition and physical activity. The target audience should be engaged throughout the process of message identification and creation. This study included focus groups with limited-resource caregivers to help identify information sources utilized, nutrition messages most likely to resonate, and preferred communication channels. Nine focus groups with 108 limited-resource caregivers were conducted. Most participants were between the ages of 21 and 44, with a majority receiving SNAP benefits. All participants were female with over half identifying as white. Two researchers coded focus group transcripts and identified themes. Participants expressed interest in nutrition particularly as it impacted children in their care. Nutrition information sources included family, health care professionals, and television celebrities. Participants expressed interest in practical nutrition content delivered through simple messaging. Communication channels frequently utilized included social media, posters in community agencies, and television news. Findings offer insight for nutrition professionals in creating and marketing nutrition messages that are competitive, accessible, and resonate with limited-resource caregivers