Solar Evolution Models with a Central Black Hole

Hawking proposed that the Sun may harbor a primordial black hole (BH) whose accretion supplies some of the solar luminosity. Such an object would have formed within the first 1 s after the Big Bang with the mass of a moon or an asteroid. These light BHs are a candidate solution to the dark matter problem, and could grow to become stellar-mass BHs if captured by stars. Here we compute the evolution of stars having such a BH at their center. We find that such objects can be surprisingly long-lived, with the lightest BHs having no influence over stellar evolution, while more massive ones consume the star over time to produce a range of observable consequences. Models of the Sun born about a BH whose mass has since grown to approximately 10−6M⊙ are compatible with current observations. In this scenario, the Sun would first dim to half its current luminosity over a span of 100 Myr as the accretion starts to generate enough energy to quench nuclear reactions. The Sun would then expand into a fully convective star, where it would shine luminously for potentially several gigayears with an enriched surface helium abundance, first as a sub-subgiant star, and later as a red straggler, before becoming a subsolar-mass BH. We also present results for a range of stellar masses and metallicities. The unique internal structures of stars harboring BHs may make it possible for asteroseismology to discover them, should they exist. We conclude with a list of open problems and predictions

Visual Social Media Use Moderates the Relationship between Initial Problematic Internet Use and Later Narcissism

Background: Little is known about the temporal directionality of relationships between problematic internet use and personality disorders such as narcissism. Objective: Although these two constructs are related at a single time, no existent study has determined whether initial problematic internet use is more strongly associated with subsequent narcissism, or vice versa. So, the aim of the research is to verify if problematic internet use predicts the narcissism or vice versa. Methods: Seventy-four university student participants were studied over a four-month period, and completed the Narcissism Personality Inventory, and Problematic Internet Use Questionnaire, at baseline and follow-up. Results: The results demonstrated a relationship between problematic internet use and narcissism at baseline. Time-lagged correlations demonstrated that problematic internet use at baseline was positively related to narcissism four-months later, but not vice versa for social media users whose use was primarily visual. This relationship did not hold for social media users whose use was primarily verbal. Conclusion: These results suggest that problematic internet use may serve to discharge narcissistic personality traits for those who use social media in a visual way, but not for those who do not engage in that form of internet use

A cognitive-behavioral model of problematic online gaming in adolescents aged 12–22 years

The aim of this study was to apply the cognitive behavioral model of problematic Internet use to the context of online game use to obtain a better understanding of problematic use of online games and its negative consequences. In total, 597 online game playing adolescents aged 12–22 years participated in this study. Results showed that the cognitive behavioral model of problematic Internet use can also be used in the context of online game use. More specifically, preference for online social interaction, mood regulation and deficient self-regulation appeared to play an important role in predicting negative outcomes from problematic online game use. Together, these cognitions and behaviors explained 79% of the variance of negative outcomes scores. These findings can be used to develop strategies that aim at reducing problematic online game behavior and its negative consequence

Adipose mesenchymal stem cells and “regenerative adipose tissue graft” (lipogems™) for musculoskeletal regeneration

Regenerative medicine is a high-potential sector of strategic developments in medicine and health industry. The perspective to cure diseases up to now relied on medical treatments of long duration and limited effectiveness, and the possibility to avoid organ transplantation renders regenerative medicine attractive. In recent years, basic and translation research held great hope for this new field with significant progress in the modulation of stem cell commitment in vitro and providing protocols for targeted clinical applications. In line with this approach, mesenchymal stem cells (MSCs) have been introduced as potential therapeutic tools to correct the breakdown of musculoskeletal disorders. MSCs are able to secrete a large number of trophic factors capable of repairing the recipient tissue through angiogenic, anti-apoptotic and anti-fibrotic mechanisms. In this context, adipose tissue is emerging as a clinically relevant and easy to harvest source of multipotent progenitors to develop regenerative therapies. The present review focuses on the clinical application of MSCs, and in particular of adipose-derived stem cells, in the musculoskeletal disorders and on the current scientific challenges. In this perspective, we discuss future developments of an innovative system (Lipogems) for musculoskeletal regeneration, yielding a non-expanded and ready-touse microfractured fat tissue product harbouring MSCs and pericytes within a preserved stromal vascular niche. The Lipogems system may also pave the way for future off-the-shelf and large-scale approaches for reconstructive procedures and regenerative medicine

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