'A predator in your home': Mothers say chatbots encouraged their sons to kill themselves Megan Garcia had no idea her teenage son Sewell, a bright and beautiful boy, had started spending hours and hours obsessively talking to an online character on the Character.ai It's like having a predator or a stranger in your home, Ms Garcia tells me in her first UK interview. And it is much more dangerous because a lot of the times children hide it - so parents don't know. Within ten months, Sewell, 14, was dead. He had taken his own life.

The only thing that Sewell was still interested in was his telephone. It was the only way to motivate him, to reach him at all. When his telephone was taken away, he would do his homework, but only to get it back. "It was a constant fight," says Megan Garcia. I had always taught my child: Don't talk to strangers, don't post any photos of yourself on the web, don't share any personal information.

This paper proves several new properties of the Meet in the Middle (MMe) bidirectional heuristic search algorithm when applied to graphs with unit edge costs. Primarily, it is shown that the length of the first path discovered by MMe never exceeds the optimal length by more than one and that if the length of the first path found is odd, then it must be optimal. These properties suggest that the search strategy should emphasize finding a complete path as soon as possible. Computational experiments demonstrate that fully exploiting these new properties can decrease the number of nodes expanded by anywhere from twofold to over tenfold.

Jennifer Turner's algebra classes were once sleepy affairs and a lot of her students struggled to stay awake. She uses Bakpax, which can read students' handwriting and auto-grade schoolwork, and she assigns lectures for students to watch online while they are at home. Using the program has provided Turner, 41, who teaches at the Gloucester County Christian School in Sewell, N.J., more flexibility in how she teaches, reserving class time for interactive exercises. "The grades for homework have been much better this year because of Bakpax," Turner said. "Students are excited to be in my room, they're telling me they love math, and those are things that I don't normally hear."

In December 2014, the publisher Scientific Research issued a retraction notice for a paper that had appeared in its journal Health with the anodyne title "Basic Principles Underlying Human Physiology." According to the notice, the action resulted from "the fact that the contents of this paper need further research and study."1 A quick look at the now-retracted article reveals that it is an effort to promote the false and wholly discredited notion that the human immunodeficiency virus (HIV) does not cause AIDS: "HIV is not etiologically involved in AIDS. It is just a common retrovirus found in AIDS conjuncturally. There is only AIDS that may not be strictly associated neither to a primary immune deficiency nor to an acquired immune deficiency. Actually, heart failure represents the causal factor of AIDS and many other'primary' immune deficiencies ..."2 Opinion pieces that "represent the viewpoint of an individual" and offer hypotheses without testing them are the opposite of science.