Social and Demographic Influences on Environmental Attitudes

Sociologists have studied environmental attitudes for over two decades. Much of this research has sought to determine what factors are related to these attitudes. Past research has shown that certain social and demographic variables tend to have a positive influence on environmentalism. One of the more valid and reliable indicators of environmentalism is the 12-item attitude scale known as the New Environmental Paradigm (NEP). That scale has been shown to consist of three sub-scales. This paper extends previous research by examining the relative influence of six independent variables (age, gender, race, education, income, and residence) on each of the sub-scales and the overall NEP scale. The analysis generally supports the hypotheses that younger people, women, whites, and people of higher education levels hold more environmental attitudes as measured by the NEP index. Income has a significant nonlinear effect

On Variations in the Peak Luminosity of Type Ia Supernovae

We explore the idea that the observed variations in the peak luminosities of Type Ia supernovae originate in part from a scatter in metallicity of the main-sequence stars that become white dwarfs. Previous, numerical, studies have not self-consistently explored metallicities greater than solar. One-dimensional Chandrasekhar mass models of SNe Ia produce most of their 56Ni in a burn to nuclear statistical equilibrium between the mass shells 0.2 and 0.8 solar masses, for which the electron to nucleon ratio is constant during the burn. We show analytically that, under these conditions, charge and mass conservation constrain the mass of 56Ni produced to depend linearly on the original metallicity of the white dwarf progenitor. Detailed post-processing of W7-like models confirms this linear dependence. The effect that we identify is most evident at metallicities larger than solar, and is in agreement with previous self-consistent calculations over the metallicity range common to both calculations. The observed scatter in the metallicity (1/3--3 times solar) of the solar neighborhood is enough to induce a 25% variation in the mass of 56Ni ejected by Type Ia supernovae. This is sufficient to vary the peak V-band brightness by approximately 0.2. This scatter in metallicity is present out to the limiting redshifts of current observations (z < 1). Sedimentation of 22Ne can possibly amplify the variation in 56Ni mass up to 50%. Further numerical studies can determine if other metallicity-induced effects, such as a change in the mass of the 56Ni-producing region, offset or enhance this variation.Comment: 4 pages, 1 figure, to appear in ApJL. Uses emulateapj.cls (included