The Hubble Diagram of the Calan/Tololo Type Ia Supernovae and the value of Ho

The Calan/Tololo supernova survey has discovered ~30 Type Ia supernovae out to z~0.1. Using BVI data for these objects and nearby SNe Ia, we have shown that there exists a significant dispersion in the intrinsic luminosities of these objects. We have devised a robust chisquare minimization technique simultaneously fitting the BVI light curves to parametrize the SN event as a function of (tb,m, m15(B)) where tb is the time of B maximum, m is the peak BVI magnitude corrected for luminosity variations, and m15(B) is a single parameter describing the whole light curve morphology. When properly corrected for m15(B), SNe Ia prove to be high precision distance indicators,yielding relative distances with errors 7-10%. The corrected peak magnitudes are used to construct BVI Hubble diagrams (HD), and with Cepheid distances recently measured with the HST to four nearby SNe Ia (37C, 72E, 81B, 90N) we derive a value of the Hubble constant of 63.1+/-3.4 (internal) km/s/Mpc. This value is ~10-15% larger than the value obtained by assuming that SNe Ia are perfect standard candles. As we have shown in Paper V, there is now strong evidence that galaxies with younger stellar population appear to host the slowest-declining, and therefore most luminous SNe Ia. Hence, the use of Pop I objects such as Cepheids to calibrate the zero point of the SNe Ia HD can easily bias the results toward luminous SNe Ia, unless the absolute magnitude-decline relation is taken into account.Comment: 32 pages, figures attached, all tables available, to appear in the Astronomical Journa

RR Lyrae Variables in M33. I. Evidence For a Field Halo Population

We present observations of RR Lyrae variables in the Local Group late-type spiral galaxy M33. Using the Advanced Camera for Surveys on the Hubble Space Telescope, we have identified 64 ab-type RR Lyraes in M33. We have estimated reddenings for these stars based on their minimum light V-I colors and metallicities based on their periods. From the distributions of these properties, we conclude that the RR Lyraes belong to two populations - one associated with the halo of M33 and the other with its disk. Given that RR Lyraes are produced by populations older than ~10 Gyr, this suggests that not only does the field halo of M33 contain an old component, but so does its disk. This is one of the best pieces of evidence for the existence of a halo field component in M33. Using a relation between RR Lyrae absolute magnitude and metallicity (Mv(RR) = 0.23[Fe/H] + 0.93), we estimate a mean distance modulus of = 24.67 +/- 0.08 for M33. This places M33 approximately 70 kpc beyond M31 in line-of-sight distance.Comment: 20 pages, 17 figures, accepted for publication in The Astronomical Journa

The Absolute Luminosities of the Calan/Tololo Type Ia Supernovae

We examine the absolute luminosities of 29 SNe Ia in the Calan/Tololo survey. We confirm a relation between the peak luminosity of the SNe and the decline rate as measured by the light curve, as suggested by Phillips (1993). We derive linear slopes to this magnitude-decline rate relation in BV(I)kc colors, using a sample with Bmax-Vmax < 0.2 mag. The scatter around this linear relation (and thus the ability to measure SNe Ia distances) ranges from 0.13 mag (in the I band) to 0.17 mag (in the B band). We also find evidence for significant correlations between the absolute magnitudes or the decline rate of the light curve, and the morphological type of the host galaxy.Comment: 21 pages, 4 figures, to appear in the Astronomical Journa

The Morphology of Type Ia Supernovae Light Curves

We present a family of six BVI template light curves for SNe Ia for days -5 and +80, based on high-quality data gathered at CTIO. These templates display a wide range of light curve morphologies, with initial decline rates of their B light curves between m15(B)=0.87 mag and 1.93 mag. We use these templates to study the general morphology of SNe Ia light curves. We find that several of the main features of the BVI templates correlate tightly with m15(B). In particular, the V light curves, which are probably a reasonably good approximation of the bolometric light curves, display an orderly progression in shapes between the most-luminous, slowest-declining events and the least-luminous, fastest-declining SNe. This supports the idea that the observed spectroscopic and photometric sequences of SNe Ia are due primarily to one parameter. Nevertheless, SNe with very similar initial decline rates do show significant differences in their light curve properties when examined in detail, suggesting the influence of one or more secondary parameters.Comment: 32 pages, 15 figures, to appear in the Astronomical Journa

A Search for Environmental Effects on Type Ia Supernovae

We use integrated colors and B and V absolute magnitudes of Type Ia supernova (SN) host galaxies in order to search for environmental effects on the SN optical properties. With the new sample of 44 SNe we confirm the conclusion by Hamuy et al. (1996a) that bright events occur preferentially in young stellar environments. We find also that the brightest SNe occur in the least luminous galaxies, a possible indication that metal-poorer neighbourhoods produce the more luminous events. The interpretation of these results is made difficult, however, due to the fact that galaxies with younger stellar populations are also lower in luminosity. In an attempt to remove this ambiguity we use models for the line strengths in the absorption spectrum of five early-type galaxies, in order to estimate metallicities and ages of the SN host galaxies. With the addition of abundance estimates from nebular analysis of the emission spectra of three spiral galaxies, we find possible further evidence that luminous SNe are produced in metal-poor neighborhoods. Further spectroscopic observations of the SN host galaxies will be necessary to test these results and assist in disentangling the age/metallicity effects on Type Ia SNe.Comment: 14 pages, 5 figures, to appear in the September 2000 issue of The Astronomical Journa

Associations between Modifiable Health-Risk Behaviors and Personality Types

Objectives: The first objective for this study was to explore if characteristics of personality type (using the Preferred Communication Style Questionnaire) are associated with the following modifiable health-risk behaviors: smoking, exercise, alcohol consumption, nutrition, sleep, depression-related stress, anxiety-related stress, healthcare professional usage, and self-discipline. The second objective for this study was to explore if characteristics of personality type are associated with (1) the quality of patient-physician relationships, (2) patient-physician communication, and (3) preferred method for receiving information. Methods: Data were collected from 10,500 adult individuals residing in the United States via an on-line, self-administered survey coordinated by Qualtrics Panels from March 14-30, 2016. Chi-square analysis was used for making comparisons between categories of personality types and items related to health-risk behaviors. Statistical significance was set at p \u3c 0.05. However, chi-square analysis with large sample sizes (e.g. 10,500 in this study) readily yields statistical significance. Practical significance was set at four or more percentage points above or below the overall mean. Results: Regarding objective 1, personality type was associated with all nine health-risk behaviors studied. Personality types within the Experiencer temperament (17% of the U.S. population) accounted for 46% of the undesirable scores we computed for health-risk behaviors. The Idealist temperament (17% of population) accounted for 32% of the undesirable scores. Conceptualizers (10% of population) accounted for 17% of the undesirable scores and Traditionalists (46% of population) accounted for 5% of the undesirable scores. Regarding objective 2, the findings showed that personality type was associated with (1) the importance people place on the patient-physician relationship, (2) which characteristics of that relationship are most desirable, (3) desire for more communication with their physician, and (4) the preferred method for receiving information. Discussion and Conclusions: Precision medicine has been proposed as a way to create a new taxonomy of disease that uses individual specific data to develop accurate diagnosis, targeted treatment, and improved health outcomes. Based on the findings of this study, we propose that inclusion of personality type is an important component of these efforts so that the health care system can conform more to the individual patient in order to increase engagement and adherence, reduce errors, minimize ineffective treatment and waste, and can be cost effective

The Reddening-Free Decline Rate Versus Luminosity Relationship for Type Ia Supernovae

We develop a method for estimating the host galaxy dust extinction for type Ia supernovae based on an observational coincidence first noted by Lira (1995), who found that the B-V evolution during the period from 30-90 days after V maximum is remarkably similar for all events, regardless of light curve shape. This fact is used to calibrate the dependence of the B(max)-V(max) and V(max)-I(max) colors on the light curve decline rate parameter delta-m15, which can, in turn, be used to separately estimate the host galaxy extinction. Using these methods to eliminate the effects of reddening, we reexamine the functional form of the decline rate versus luminosity relationship and provide an updated estimate of the Hubble constant of Ho = 63.3 +- 2.2(internal) +- 3.5(external) km/s/Mpc.Comment: 32 pages, 10 figures, AJ 1999 in pres

Development of the Adherence Predictive Index (API) for Medication Taking

The objective for this study was to explore if characteristics of personality type using the Preferred Communication Style Questionnaire, in concert with the demographic characteristics of age, education, and race/ethnicity, are associated with, and help predict, individuals’ medication adherence behavior. Data were collected via an on-line survey, sent to a sample of adults residing in the United States, between April 28 and June 22, 2015. Out of 26,173 responses to the survey, 16,736 reported taking one or more medications and were eligible for inclusion in this study. The development of the Adherence Predictive Index (API) used mean Morisky Medication Adherence Scale (MMAS-8) scores for each of eight personality types as a starting point. API scores were calculated by adding or subtracting specific values to each group’s mean MMAS-8 score based on personality type, age, education and race/ethnicity characteristics which were demonstrated to have significant effects on adherence. The weighting system was informed by linear regression, logistic regression, personality type literature, researcher experience, and previous qualitative and quantitative research. The resultant score was converted to an API score that ranged from 1 to 5 so that it would be feasible for health care providers to understand and use. The findings showed that an Adherence Predictive Index (API) could be developed based upon a relatively small number of questions that focus on personality type and generational, educational, and cultural experiences. It was developed in order to be a component of a comprehensive program that has the goals of (1) identifying and describing specific behavioral strategies individuals are most likely to successfully employ, (2) motivating patients by using their preferred communication style, and (3) predicting each patient’s propensity to adhere. Future research is needed to evaluate the index’s validity, sensitivity, and effectiveness in actual practice compared with other risk indices.   Type: Original Researc