30 research outputs found
Self-Injurious Behavior in Adolescents
Janis Whitlock discusses the epidemiology and and care of adolescents undertaking nonsuicidal self-injury, also called “deliberate self-harm.
Multi-Objective Blended Ensemble for Highly Imbalanced Sequence Aware Tweet Engagement Prediction
In this paper we provide a description of the methods we used as team BanaNeverAlone for the ACM RecSys Challenge 2020, organized by Twitter. The challenge addresses the problem of user engagement prediction: the goal is to predict the probability of a user engagement (Like, Reply, Retweet or Retweet with comment), based on a series of past interactions on the Twitter platform. Our proposed solution relies on several features that we extracted from the original dataset, as well as on consolidated models, such as gradient boosting for decision trees and neural networks. The ensemble model, built using blending, and a multi-objective optimization allowed our team to rank in position 4
Colossal Positive and Negative Thermal Expansion in the Framework Material Ag3[Co(CN)6]
We show that silver(I) hexacyanocobaltate(III), Ag3[Co(CN)6], exhibits positive and negative thermal expansion an order of magnitude greater than that seen in other crystalline materials. This framework material expands along one set of directions at a rate comparable to the most weakly bound solids known. By flexing like lattice fencing, the framework couples this to a contraction along a perpendicular direction. This gives negative thermal expansion that is 14 times larger than in ZrW2O8. Density functional theory calculations quantify both the low energy associated with this flexibility and the role of argentophilic (Ag+...Ag+) interactions. This study illustrates how the mechanical properties of a van der Waals solid might be engineered into a rigid, useable framework
Behaviour of NTE Material Ag3[Co(CN)6] under Pressure
Recent discovery of colossal negative thermal expansion (NTE) behaviour in Silver Hexacyanocobaltate Ag3[Co(CN)6] has triggered interest among researchers to understand the basic mechanism causing such an unusual behaviour. This report presents our results on the behaviour of Ag3[Co(CN)6] using in-situ high pressure Raman and FTIR spectroscopy. The reported trigonal-monoclinic phase transition occurring in this compound is observed at 0.2 GPa. Upon increasing the pressure further, Ag3[Co(CN)6] becomes irreversibly amorphous above 13 GPa.by Pallavi Ghalsasi and Ravi Tripath