San Diego State University

About: San Diego State University is a education organization based out in San Diego, California, United States. It is known for research contribution in the topics: Population & Poison control. The organization has 12418 authors who have published 27950 publications receiving 1192375 citations. The organization is also known as: SDSU & San Diego State College.

The First Systematic Study of Type Ibc Supernova Multi-band Light Curves

Abstract: We present detailed optical photometry for 25 Type Ibc supernovae within d\approx150 Mpc obtained with the robotic Palomar 60-inch telescope in 2004-2007. This study represents the first uniform, systematic, and statistical sample of multi-band SNe Ibc light curves available to date. We correct the light curves for host galaxy extinction using a new technique based on the photometric color evolution, namely, we show that the (V-R) color of extinction-corrected SNe Ibc at t\approx10 days after V-band maximum is tightly distributed, (V-R)=0.26+-0.06 mag. Using this technique, we find that SNe Ibc typically suffer from significant host galaxy extinction, E(B-V)\approx0.4 mag. A comparison of the extinction-corrected light curves for SNe Ib and Ic reveals that they are statistically indistinguishable, both in luminosity and decline rate. We report peak absolute magnitudes of M_R=-17.9+-0.9 mag and M_R=-18.3+-0.6 mag for SNe Ib and Ic, respectively. Focusing on the broad-lined SNe Ic, we find that they are more luminous than the normal SNe Ibc sample, M_R=-19.0+-1.1 mag, with a probability of only 1.6% that they are drawn from the same population of explosions. By comparing the peak absolute magnitudes of SNe Ic-BL with those inferred for local engine-driven explosions (GRB-SN 1998bw, XRF-SN 2006aj, and SN2009bb) we find a 25% probability that they are drawn from the SNe Ic-BL population. Finally, we fit analytic models to the light-curves to derive typical Ni-56 masses of M_Ni \approx0.2 and 0.5 M_sun for SNe Ibc and SNe Ic-BL, respectively. With reasonable assumptions for the photospheric velocities, we extract kinetic energy and ejecta mass values of M_ej \approx 2 M_sun and E_K\approx1e+51 erg for SNe Ibc, while for SNe Ic-BL we find higher values, M_ej\approx5 M_sun and E_K\approx1e+52 erg. We discuss the implications for the progenitors of SNe Ibc and their relation to engine-driven explosions [ABRIDGED].

Conceptualizing and Measuring Ethnic Discrimination in Health Research

Abstract: This paper presents the General Ethnic Discrimination Scale, an 18-item measure of perceived ethnic discrimination that can be used in health research with any ethnic group. The 1569 participants (half college students, half community adults) completed the General Ethnic Discrimination scale and measures of cigarette smoking and of psychiatric symptoms. Results revealed that the General Ethnic Discrimination subscales model the latent construct of perceived ethnic discrimination equally well for Blacks, Latinos, Asians, and Whites. Discrimination was strongly related to psychiatric symptoms and to current cigarette smoking for ethnic minorities and Whites alike, but such relationships were stronger for ethnic minorities. Minorities who experienced frequent discrimination were 2.3 times more likely than their low-discrimination counterparts to be smokers. This 5th grade reading-level scale takes 10 min to complete and has sufficient, initial psychometric integrity for use in clinical and community health studies.

Reliability and validity of the Sedentary Behavior Questionnaire (SBQ) for adults.

Abstract: Background: Sedentary behavior is related to obesity, but measures of sedentary behaviors are lacking for adults. The purpose of this study was to examine the reliability and validity of the Sedentary Behavior Questionnaire (SBQ) among overweight adults. Methods: Participants were 49 adults for the 2 week test-retest reliability study (67% female, 53% white, mean age = 20) and 401 overweight women (mean age = 41, 61% white) and 441 overweight men (mean age = 44, 81% white) for the validity study. The SBQ consisted of reports of time spent in 9 sedentary behaviors. Outcomes for validity included accelerometer measured inactivity, sitting time (International Physical Activity Questionnaire), and BMI. Intraclass correlation coefficients (ICCs) assessed reliability and partial correlations assessed validity. Results: ICCs were acceptable for all items and the total scale (range = .51–.93). For men, there were significant relationships of SBQ items with IPAQ sitting time and BMI. For women, there were relationships between the SBQ and accelerometer inactivity minutes, IPAQ sitting time, and BMI. Conclusions: The SBQ has acceptable measurement properties for use among overweight adults. Specific measures of sedentary behavior should be included in studies and population surveillance.

The Spread of Va Mycorrhizal Fungal Hyphae in the Soil: Inoculum Types and External Hyphal Architecture

Abstract: Different forms of vesicular-arbuscular mycorrhizal fungal inoculum are found in soil patches with differing histories. These inoculum types include spores, infected root fragments, and extramatric...