Protoplanetary Disk Resonances and Type I Migration

Waves reflected by the inner edge of a protoplanetary disk are shown to significantly modify Type I migration, even allowing the trapping of planets near the inner disk edge for small planets in a range of disk parameters. This may inform the distribution planets close to their central stars, as observed by the Kepler mission.Comment: 6 pages, 3 figures, accepted by Ap

Ten Years Ago in FP

Offers excerpts from three articles from the Summer 1993 issue of 'Foreign Policy.' Topics including the protection of Kurds in Iraq and Turkey, financial commitment of Americans to a United States foreign policy that promotes democracy worldwide, and British entry into the European Union; Title of articles which are written by Morton I. Abramowitz, Jagdish Bhagwati, and Morton H. Halperin

The effects of viewing angle on the mass distribution of exoplanets

We present a mathematical method to statistically decouple the effects of unknown inclination angles on the mass distribution of exoplanets that have been discovered using radial-velocity techniques. The method is based on the distribution of the product of two random variables. Thus, if one assumes a true mass distribution, the method makes it possible to recover the observed distribution. We compare our prediction with available radial-velocity data. Assuming the true mass function is described by a power-law, the minimum mass function that we recover proves a good fit to the observed distribution at both mass ends. In particular, it provides an alternative explanation for the observed low-mass decline, usually explained as sample incompleteness. In addition, the peak observed near the the low-mass end arises naturally in the predicted distribution as a consequence of imposing a low-mass cutoff in the true-distribution. If the low-mass bins below 0.02 M_J are complete, then the mass distribution in this regime is heavily affected by the small fraction of lowly inclined interlopers that are actually more massive companions. Finally, we also present evidence that the exoplanet mass distribution changes form towards low-mass, implying that a single power law may not adequately describe the sample population.Comment: ApJ, accepte

Voigt Profile Fitting to Quasar Absorption Lines: An Analytic Approximation to the Voigt-Hjerting Function

The Voigt-Hjerting function is fundamental in order to correctly model the profiles of absorption lines imprinted in the spectra of bright background sources by intervening absorbing systems. In this work we present a simple analytic approximation to this function in the context of absorption line profiles of intergalactic HI absorbers. Using basic calculus tools, we derive an analytic expression for the Voigt-Hjerting function that contains only fourth order polynomial and Gaussian functions. In connection with the absorption coefficient of intergalactic neutral hydrogen, this approximation is suitable for modeling Voigt profiles with an accuracy of $10^{-4}$ or better for an arbitrary wavelength baseline, for column densities up to $N_{HI} = 10^{22} cm^{-2}$, and for damping parameters $a \lesssim 10^{-4}$, i.e. the entire range of parameters characteristic to all Lyman transitions arising in a variety of HI absorbing systems such as Lyman Alpha Forest clouds, Lyman Limit systems and Damped Lyman Alpha systems. We hence present an approximation to the Voigt-Hjerting function that is both accurate and flexible to implement in various types of programming languages and machines, and with which Voigt profiles can be calculated in a reliable and very simple manner.Comment: 11 pages, 8 figures, accepted for publication in MNRAS after referee's revision and corresponding change

Accumulation of Biomass and Mineral Elements with Calendar Time by Corn: Application of the Expanded Growth Model

The expanded growth model is developed to describe accumulation of plant biomass (Mg ha−1) and mineral elements (kg ha−1) in with calendar time (wk). Accumulation of plant biomass with calendar time occurs as a result of photosynthesis for green land-based plants. A corresponding accumulation of mineral elements such as nitrogen, phosphorus, and potassium occurs from the soil through plant roots. In this analysis, the expanded growth model is tested against high quality, published data on corn (Zea mays L.) growth. Data from a field study in South Carolina was used to evaluate the application of the model, where the planting time of April 2 in the field study maximized the capture of solar energy for biomass production. The growth model predicts a simple linear relationship between biomass yield and the growth quantifier, which is confirmed with the data. The growth quantifier incorporates the unit processes of distribution of solar energy which drives biomass accumulation by photosynthesis, partitioning of biomass between light-gathering and structural components of the plants, and an aging function. A hyperbolic relationship between plant nutrient uptake and biomass yield is assumed, and is confirmed for the mineral elements nitrogen (N), phosphorus (P), and potassium (K). It is concluded that the rate limiting process in the system is biomass accumulation by photosynthesis and that nutrient accumulation occurs in virtual equilibrium with biomass accumulation

Holy anorexia: Eating disorders symptomatology and religiosity among Muslim women in the United Arab Emirates

© 2017 Elsevier B.V. There is a substantial body of literature reporting a negative association between religiosity and psychiatric symptoms. In the context of eating disorders, however, this relationship appears to be reversed. The few studies exploring the relationship between religiosity and eating disorders have mostly focused on the Judeo-Christian religious traditions in Western nations. The present study examines this relationship among Muslim college women from the United Arab Emirates (UAE). All participants (N = 1069) independently completed the religious commitment inventory (RCI-10) and the eating attitudes test (EAT-26). As hypothesised, there was a positive association between religiosity and eating disorders symptoms. Furthermore, those scoring above the EAT-26 cut-off reported significantly greater levels of religiosity. These findings suggest that heightened religiosity among young Emirati women may represent a vulnerability factor for eating disorders. Preventative initiatives in the UAE should consider focusing on religiosity

Radial Basis Functions for the Sphere

In this paper we compute the ultraspherical series expansions for the more commonly used radial basis functions. In several special cases we provide asymptotic estimates for the decay rate of the coefficients involved. knowledge of the decay rate of these coefficients is useful because they enable error estimates for spherical interpolation

A qualitative study exploring perceptions and attitudes of community pharmacists about extended pharmacy services in Lahore, Pakistan

Background In recent decades, community pharmacies reported a change of business model, whereby a shift from traditional services to the provision of extended roles was observed. However, such delivery of extended pharmacy services (EPS) is reported from the developed world, and there is scarcity of information from the developing nations. Within this context, the present study was aimed to explore knowledge, perception and attitude of community pharmacists (CPs) about EPS and their readiness and acceptance for practice change in the city of Lahore, Pakistan. Methods A qualitative approach was used to gain an in-depth knowledge of the issues. By using a semi-structured interview guide, 12 CPs practicing in the city of Lahore, Pakistan were conveniently selected. All interviews were audio-taped, transcribed verbatim, and were then analyzed for thematic contents by the standard content analysis framework. Results Thematic content analysis yielded five major themes. (1) Familiarity with EPS, (2) current practice of EPS, (3) training needed to provide EPS, (4) acceptance of EPS and (5) barriers toward EPS. Majority of the CPs were unaware of EPS and only a handful had the concept of extended services. Although majority of our study respondents were unaware of pharmaceutical care, they were ready to accept practice change if provided with the required skills and training. Lack of personal knowledge, poor public awareness, inadequate physician-pharmacist collaboration and deprived salary structures were reported as barriers towards the provision of EPS at the practice settings. Conclusion Although the study reported poor awareness towards EPS, the findings indicated a number of key themes that can be used in establishing the concept of EPS in Pakistan. Over all, CPs reported a positive attitude toward practice change provided to the support and facilitation of health and community based agencies in Pakistan

Dynamic Responsiveness in the U.S. Senate

I develop a theory of dynamic responsiveness that suggests that parties that win elections choose candidates who are more extreme and parties that lose elections choose candidates who are more moderate. Moreover, the size of past victories matters. Close elections yield little change, but landslides yield larger changes in the candidates offered by both parties. I test this theory by analyzing the relationship between Republican vote share in U.S. Senate elections and the ideology of candidates offered in the subsequent election. The results show that Republican (Democratic) victories in past elections yield candidates who are more (less) conservative in subsequent elections, and the effect is proportional to the margin of victory. This suggests that parties or candidates pay attention to past election returns. One major implication is that parties may remain polarized in spite of their responsiveness to the median voter