Momo – the story and the picture – are utterly horrifying. And that's just about the only thing anyone can know for sure. The story is linked with a bizarre and chilling photo, as well as a series of stories that are just as sinister. The picture is being used by people on WhatsApp who trick young people into extreme behaviour that includes taking their own lives, according to those reports. It has led to warnings from the police, telling children to be careful and their parents to look after them. Many include the image, and suggestions that it has some sort of unknown power.

PRINCETON, NEW JERSEY – Venezuelan President Nicolas Maduro accused political foes of trying to kill him during an open-air speech Saturday using explosives-laden drones, prompting a host of questions about the alleged attack and who might have been behind it. Wherever the investigation leads, Maduro's allegations raised the specter of unmanned aerial vehicles being used by militant groups or others to launch bombing, chemical or biological attacks, a tactic that has long worried security experts. The market for commercial drones has flourished in recent years amid widespread availability and falling prices. So-called quadcopters -- drones with four rotors -- that can be operated from more than a mile away (1.6 km) and can fly for more than 20 minutes on one charge cost less than $1,000 to buy online, though they are generally capable of carrying only a limited payload. Militant groups such as Islamic State have used drones to carry out attacks by dropping grenades or crashing into infrastructure.

Venezuela's interior minister says six people have been arrested, after what President Nicolas Maduro says was an assassination attempt against him. The president accuses Colombia and a group of US financiers of trying to kill him. Venezuela's opposition fears the government will launch a crackdown. Colombia's Foreign Affairs Ministry called that accusation absurd, and in Washington, President Donald Trump's national security adviser John Bolton strongly denied any US role.

Venezuelan investigators hunting for a band of assailants allegedly behind a failed attempt to assassinate President Nicolas Maduro with explosives-laden drones have raided hotels and seized vehicles while grilling six suspects for details of the plot.

CARACAS – Authorities detained six people suspected of using explosives-laden drones in a failed bid to assassinate Venezuelan President Nicolas Maduro, officials said Sunday, in what one witness described as a terrifying attack that shook her apartment building. The government alleged that opposition factions conspired with assailants in Miami and Bogota, although they offered no specific evidence. Opposition leaders decried Maduro for broadly singling out his political opponents, and they warned he may use it to further suppress his critics. The thwarted attack comes as Venezuela is reeling from a worsening economic and humanitarian crisis and Maduro has grown increasingly isolated. Foreign nations, including the United States, are slapping economic sanctions against a growing list of high-ranking officials and decrying his government as an autocratic regime.

Missing data imputation can help improve the performance of prediction models in situations where missing data hide useful information. This paper compares methods for imputing missing categorical data for supervised classification tasks. We experiment on two machine learning benchmark datasets with missing categorical data, comparing classifiers trained on non-imputed (i.e., one-hot encoded) or imputed data with different levels of additional missing-data perturbation. We show imputation methods can increase predictive accuracy in the presence of missing-data perturbation, which can actually improve prediction accuracy by regularizing the classifier. We achieve the state-of-the-art on the Adult dataset with missing-data perturbation and k-nearest-neighbors (k-NN) imputation.

NIMFA is an open-source Python library that provides a unified interface to nonnegative matrix factorization algorithms. It includes implementations of state-of-the-art factorization methods, initialization approaches, and quality scoring. It supports both dense and sparse matrix representation. NIMFA's component-based implementation and hierarchical design should help the users to employ already implemented techniques or design and code new strategies for matrix factorization tasks.

This is a very serious, looming threat that we are currently unprepared to confront,

Maduro often blames the United States, which has imposed sanctions against officials in his government, of "conspiracy" and blamed U.S. politicians of fomenting plans to topple him to end nearly two decades of socialism in Venezuela.

A drone loaded with explosives detonated near a military event where Venezuelan President Nicolas Maduro was giving a speech, but he escaped unharmed in what the embattled leader called an assassination attempt. Seven people were wounded on Saturday in the apparent attack, which came as Maduro celebrated the National Guard's 81st anniversary in the capital, Caracas. Maduro later said "everything points" to a right-wing plot that an initial investigation suggested was linked to Colombia and the US state of Florida, where many Venezuelan exiles live. Several perpetrators were caught, he said, without elaborating. "This was an assassination attempt, they tried to assassinate me," Maduro said in a televised address.