1,749 research outputs found
The Horseshoe Estimator: Posterior Concentration around Nearly Black Vectors
We consider the horseshoe estimator due to Carvalho, Polson and Scott (2010)
for the multivariate normal mean model in the situation that the mean vector is
sparse in the nearly black sense. We assume the frequentist framework where the
data is generated according to a fixed mean vector. We show that if the number
of nonzero parameters of the mean vector is known, the horseshoe estimator
attains the minimax risk, possibly up to a multiplicative constant. We
provide conditions under which the horseshoe estimator combined with an
empirical Bayes estimate of the number of nonzero means still yields the
minimax risk. We furthermore prove an upper bound on the rate of contraction of
the posterior distribution around the horseshoe estimator, and a lower bound on
the posterior variance. These bounds indicate that the posterior distribution
of the horseshoe prior may be more informative than that of other one-component
priors, including the Lasso.Comment: This version differs from the final published version in pagination
and typographical detail; Available at
http://projecteuclid.org/euclid.ejs/141813426
Changes in contact and support within intergenerational relationships in the Netherlands: A cohort and time-sequential perspective
This study investigates whether the frequency of contact and support exchanged in relationships between parents and adult children declines over successive cohorts and over individual time in the Netherlands. Respondents included a birth cohort from 1928 to 1937 with data collected in 1992 (N=941) and in 2002 (N=574) and a birth cohort from 1938 to 1947 with data collected in 2002 (N=884). We assessed cohort and time-sequential changes. Parents of the later cohort had more contact and support exchanges with their children than the earlier cohort, revealing that families have not declined in importance. Furthermore, longitudinally, contact and supportive exchanges with adult children 1
Race/Ethnicity in Candidate Experiments:a Meta-Analysis and the Case for Shared Identification
Does race/ethnicity effect how voters assess political candidates? To address this question, we pooled data from 43 published candidate experiments from the last 10 years with a combined N of 305,632. We distinguish three different schools of thought that authors apply: unjust stereotypes, useful stereotypes and shared identification. Voters use “unjust stereotypes” and discriminate against candidates of color or use “useful stereotypes” that inform them of the policy positions they expect candidates to defend. Scholars increasingly apply a “shared identification” perspective and study the effect of congruence between voter and candidate characteristics on assessments. The results show that voters do not assess racial/ethnic minority candidates differently than their majority (white) counterparts. This does not hold for Asian candidates in the US: voters assess them slightly more positively than majority candidates, although this effect is small (0.76 percentage points). Shared identification matters enormously: when voters share the same race/ethnicity as a candidate they assess them 7.9 percentage points higher than that they assess majority candidates. This effect is substantively meaningful and significant for all most researched (US-based) races/ethnicities. This indicates that the underrepresentation of racial/ethnic minority citizens cannot be explained by voting behavior, but possibly by supply side effects
The miniJPAS survey : A preview of the Universe in 56 colors
The Javalambre-Physics of the Accelerating Universe Astrophysical Survey (J-PAS) will scan thousands of square degrees of the northern sky with a unique set of 56 filters using the dedicated 2.55 m Javalambre Survey Telescope (JST) at the Javalambre Astrophysical Observatory. Prior to the installation of the main camera (4.2 deg(2) field-of-view with 1.2 Gpixels), the JST was equipped with the JPAS-Pathfinder, a one CCD camera with a 0.3 deg(2) field-of-view and plate scale of 0.23 arcsec pixel(-1). To demonstrate the scientific potential of J-PAS, the JPAS-Pathfinder camera was used to perform miniJPAS, a similar to 1 deg(2) survey of the AEGIS field (along the Extended Groth Strip). The field was observed with the 56 J-PAS filters, which include 54 narrow band (FWHM similar to 145 angstrom) and two broader filters extending to the UV and the near-infrared, complemented by the u, g, r, i SDSS broad band filters. In this miniJPAS survey overview paper, we present the miniJPAS data set (images and catalogs), as we highlight key aspects and applications of these unique spectro-photometric data and describe how to access the public data products. The data parameters reach depths of mag(AB) similar or equal to 22-23.5 in the 54 narrow band filters and up to 24 in the broader filters (5 sigma in a 3 '' aperture). The miniJPAS primary catalog contains more than 64 000 sources detected in the r band and with matched photometry in all other bands. This catalog is 99% complete at r = 23.6 (r = 22.7) mag for point-like (extended) sources. We show that our photometric redshifts have an accuracy better than 1% for all sources up to r = 22.5, and a precision of 2. The miniJPAS survey demonstrates the capability of the J-PAS filter system to accurately characterize a broad variety of sources and paves the way for the upcoming arrival of J-PAS, which will multiply this data by three orders of magnitude.Peer reviewe
Examining potential school contextual influences on gambling among high school youth
Background and Objectives: Gambling is an increasing concern among adolescence, yet there has been limited investigation into school-level factors that may increase the risk for gambling. The current study examined the relationship between substance use and gambling, and explored the influence of school context on adolescent gambling. Methods: Data come from 25,456 students in 58 high schools participating in the Maryland Safe and Supportive Schools Initiative. Youth-reports of socio-demographics, lifetime gambling, and past-month substance use (ie, alcohol, cigarette, marijuana, non-medical prescription drug) were collected. School-level characteristics were student suspension rate, student mobility, percentage of students receiving free/reduce-priced meals, percentage of African American students, urbanicity, gambling prevalence, gambling problem prevalence, and substance use prevalence. Weighted multilevel analyses were conducted. Results: One-third (n = 8,318) reported lifetime gambling, and 10% (n = 2,580) of the full sample, or 31% of the gamblers, experienced gambling problems. Being male and alcohol, marijuana, and non-medical prescription drug use were associated with twice the odds of gambling. Among gamblers, being male, African American, and cigarette, marijuana, and non-medical prescription drug use were associated with higher odds of gambling problems. The school-level factors of suspension rate and percentage of African American had minimal, inverse associations with gambling; however, none were related to gambling problems. Conclusions: Multilevel results indicated that adolescents that are male and use substances are more likely to gamble and have gambling problems. Scientific Significance: The findings indicate a need for prevention programs targeting risky behaviors to also target gambling as such behaviors often co-occur among adolescents
Surgical vs Conservative Treatments for Adolescent Shoulder Instability
Shoulder instability following an anterior shoulder dislocation is common in active adolescent populations and can have negative long-term impacts on activities of daily living and competitive physical activities. Historically, shoulder instability following anterior shoulder dislocation is treated surgically due to the high risk of recurrent instability. However, conservative treatments may be appropriate in certain adolescent populations due to skeletal immaturity. This article investigates the effectiveness of conservative therapy compared to surgical repair in the adolescent population with shoulder instability following anterior shoulder dislocation
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