Monitoring Observations of the Jupiter-Family Comet 17P/Holmes during 2014 Perihelion Passage

We performed a monitoring observation of a Jupiter-Family comet, 17P/Holmes, during its 2014 perihelion passage to investigate its secular change in activity. The comet has drawn the attention of astronomers since its historic outburst in 2007, and this occasion was its first perihelion passage since then. We analyzed the obtained data using aperture photometry package and derived the Afrho parameter, a proxy for the dust production rate. We found that Afrho showed asymmetric properties with respect to the perihelion passage: it increased moderately from 100 cm at the heliocentric distance r_h=2.6-3.1 AU to a maximal value of 185 cm at r_h = 2.2 AU (near the perihelion) during the inbound orbit, while dropping rapidly to 35 cm at r_h = 3.2 AU during the outbound orbit. We applied a model for characterizing dust production rates as a function of r_h and found that the fractional active area of the cometary nucleus had dropped from 20%-40% in 2008-2011 (around the aphelion) to 0.1%-0.3% in 2014-2015 (around the perihelion). This result suggests that a dust mantle would have developed rapidly in only one orbital revolution around the sun. Although a minor eruption was observed on UT 2015 January 26 at r_h = 3.0 AU, the areas excavated by the 2007 outburst would be covered with a layer of dust (<~ 10 cm depth) which would be enough to insulate the subsurface ice and to keep the nucleus in a state of low activity.Comment: 25 pages, 6 figures, 2 tables, ApJ accepted on December 29, 201

Reevaluating the “Deaths of Despair” Narrative: Racial/Ethnic Heterogeneity in the Trend of Psychological Distress-Related Death, 1997-2014

Despite the significant scientific advancement in deciphering the “deaths of despair” narrative, most relevant studies have focused on drug-, alcohol-, and suicide-related (DAS) deaths. This study directly investigated despair as a determinant of death and the temporal variation and racial heterogeneity among individuals. We used psychological distress (PD) as a proxy for despair and drew data from the U.S. National Health Interview Survey Linked Mortality Files 1997-2014, CDC Multiple Cause of Death database 1997-2014, CDC bridged-race population files 1997-2014, Current Population Survey 1997-1999, and the American Community Survey 2000-2014. We used Cox proportional hazards models to estimate mortality hazard ratios of PD and compared age-standardized PD- and DAS-related mortality rates by race/ethnicity and over time. We found while Whites had a lower prevalence of PD than Blacks and Hispanics throughout the whole period, they underwent distinctive increases in PD-related death and have had a higher PD-related mortality rate than Blacks and Hispanics since the early 2000s. This was predominantly due to Whites’ relatively high and increasing vulnerability to PD less the prevalence of PD. Furthermore, PD induced a more pervasive mortality consequence than DAS combined for Whites and Blacks. In addition, PD- and DAS-related deaths displayed a concordant trend among Whites but divergent patterns for Blacks and Hispanics. These finding suggest that (1) DAS-related deaths underestimated the mortality consequence of despair for Whites and Blacks but overestimated it for Hispanics; and (2) despair partially contributed to the DAS trend among Whites but probably not for Blacks and Hispanics

What explains the different rates of human papillomavirus vaccination among adolescent males and females in the United States?

Purpose: To identify factors that explain differences in HPV vaccination rates for male and female adolescents and to determine self-reported barriers by parents affecting vaccination decisions. Methods: The sample included adolescents 13–17 years old with a vaccination record documented in the 2012 and 2013 National Immunization Survey-Teen dataset. A logistic regression model was developed with 13 socio-demographic factors and survey year, along with significant interaction pairs with gender. Results: Subjects included 20,355 and 18,350 adolescent boys and girls, respectively. About half of the females (56%) received at least one dose of HPV vaccine, compared to 28% of males. Several factors differed between males and females, including higher vaccination rates among non-Hispanic Black males and lower vaccination rates for non-Hispanic Black females compared to Whites; and a stronger association with health care provider recommendation among males. The most common parental reasons for not vaccinating their children included ‘not recommended by a health care provider’ for males (24%), and ‘unnecessary’ for females (18%). Conclusion: We found a significant gender interaction with several socio-demographic variables in predicting vaccination uptake. These gender differences may be partially an artifact of timing, because male vaccination became routine approximately five years after female vaccination. Keywords: Human papillomavirus, Adolescent health, Vaccination, NIS-Teen, Gender interactio