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Author(s): J. Ortega-Barón [sup.1] , J. M. Machimbarrena [sup.2] , I. Montiel [sup.1] , J. González-Cabrera [sup.1] Author Affiliations: (1) grid.13825.3d, 0000 0004 0458 0356, Faculty of Education, Universidad Internacional [...], In recent years, viral challenges on the Internet have become a very frequent phenomenon. These allude to the actions that are proposed to Internet users to record themselves performing a challenge and disseminate it on different online platforms so that other users will also perform it. Despite its rapid expansion, there is no evidence of any validated assessment tool of this phenomenon. To meet this need, the Viral Internet Challenges Scale (VICH-S) was designed. The main objective of this study was to establish the psychometric properties of this scale, the prevalence of different types of challenges (social, solidary, and dangerous), as well as the single or conjoint performance of these types of challenges using the VICH-S. Furthermore, the construct validity of the scale was tested with these variables: Fear of Missing Out, Loss of Connection (nomophobia), Self-Online, and Emotional Attention Online. Participants were 417 preadolescents (41.2% boys) with age ranging from 10 to 14 years. Exploratory factor analysis of the VICH-S scale revealed the existence of two factors: Challenge Satisfaction and Social Motivation. Convergent validity indicators showed positive and significant correlations between these two dimensions and the Fear of Missing Out, Loss of Connection (nomophobia), Self-Online, and Emotional Attention Online. The most frequent challenges were social challenges (80.3%), followed by solidary (20.6%) and dangerous challenges (7.7%). This study has relevant implications, as the VICH-S presents adequate psychometric properties to evaluate this barely explored and growing phenomenon of viral challenges on the Internet in preadolescence.

We examine the effect of photodarkening-induced pump light absorption on Yb-doped fiber thermal loading. In these experiments, the fiber is cladding pumped at 915 nm, air cooled by natural convection, and monitored with a midinfrared thermal camera. The fiber temperature is found to correlate with progressive photodarkening. The maximum observed fiber temperature was 120 [degrees]C, recorded at a pump power of 10.5 W. The observed increase in fiber temperature can be explained by a model that takes into account the combined effects of the Yb-silica quantum defect, the temperature dependence of the Yb-absorption cross section, and photodarkening-induced loss at 915 nm. We hypothesize that the latter effect results in the progressive activation of temperature-dependent photochemical processes (e.g., bleaching) and is ah important consideration with regard to the accurate modeling of Yb-doped fiber photodarkening kinetics. OCIS codes: 140.3510, 160.5690, 140.6810, 140.3615.