People often think that the big city is a dangerous place: they worry that they might get murdered, for instance. Being killed on purpose is more likely in town, according to new research, but it is so rare compared to dying in an accident of some type that in fact you would be much more likely to die unexpectedly in the countryside - in America, anyway.

I studien har man undersökt 27.000 män mellan 45 och 82 år under sexton års tid. Den visar att även om man räknar bort faktorer som fysisk aktivitet, sömn, matvanor och vikt så ökar risken dö i hjärtinfarkt eller någon annan hjärtsjukdom med 27 procent om man hoppar över frukosten.

In the study, 10 untrained Goffin’s cockatoos faced a puzzle box showing a nut behind a transparent door secured by a series of five different interlocking devices, each one jamming the next along in the series. To retrieve the nut the birds had to first remove a pin, then a screw, then a bolt, then turn a wheel 90 degrees, and then shift a latch sideways. § One bird, called Pipin, cracked the problem unassisted in less than two hours, and several others did it after being helped either by being presented with the series of locks incrementally or being allowed to watch a skilled partner doing it.

In this post I will describe one small but important part of the theory of causal inference, a causal calculus developed by Pearl. This causal calculus is a set of three simple but powerful algebraic rules which can be used to make inferences about causal relationships. In particular, I’ll explain how the causal calculus can sometimes (but not always!) be used to infer causation from a set of data, even when a randomized controlled experiment is not possible. Also in the post, I’ll describe some of the limits of the causal calculus, and some of my own speculations and questions.

We study fifteen months of human mobility data for one and a half million individuals and find that human mobility traces are highly unique. In fact, in a dataset where the location of an individual is specified hourly, and with a spatial resolution equal to that given by the carrier's antennas, four spatio-temporal points are enough to uniquely identify 95% of the individuals. We coarsen the data spatially and temporally to find a formula for the uniqueness of human mobility traces given their resolution and the available outside information. This formula shows that the uniqueness of mobility traces decays approximately as the 1/10 power of their resolution. Hence, even coarse datasets provide little anonymity. These findings represent fundamental constraints to an individual's privacy and have important implications for the design of frameworks and institutions dedicated to protect the privacy of individuals.

The levels of exposure to radiation following the leaks and explosions at the earthquake-damaged Fukushima Daiichi nuclear power station in 2011 were so low that they led today to this important conclusion from experts convened in Vienna by the United Nations Scientific Committee on the Effect of Atomic Radiation: It is unlikely to be able to attribute any health effects in the future among the general public and the vast majority of workers.

ETT travel timeSeating a maximum of six passengers per tube plus a baggage compartment, the ETT can travel at a speed of approximately 4,000 miles per hour while remaining airless and frictionless. Thanks to magnetic levitation, the vacuum speed means you can go from New York to Los Angeles in a mere 45 minutes, New York to Beijing in two hours, or around the world in only six hours. Despite the high velocity, passengers will not experience discomfort because the tube apparently only produce 1G of force at top speed, comparable to riding in a normal car on a highway.

Cognitive neuroscientist Sid Kouider of CNRS, the French national research agency, in Paris watched for swings in electrical activity, called event-related potentials (ERPs), in the babies' brains. In babies who were at least 1 year old, Kouider saw an ERP pattern similar to an adult's, but it was about three times slower. The team was surprised to see that the 5-month-olds also showed a late slow wave, although it was weaker and more drawn out than in the older babies. Kouider speculates that the late slow wave may be present in babies as young as 2 months.

Using nuclear power in place of fossil-fuel energy sources, such as coal, has prevented some 1.8 million air pollution-related deaths globally and could save millions of more lives in coming decades, concludes a study. The researchers also find that nuclear energy prevents emissions of huge quantities of greenhouse gases. These estimates help make the case that policymakers should continue to rely on and expand nuclear power in place of fossil fuels to mitigate climate change, the authors say (Environ. Sci. Technol., DOI: 10.1021/es3051197).

There’s no comfort in the statistics for missions to Mars. To date over 60% of the missions have failed. The scientists and engineers of these undertakings use phrases like “Six Minutes of Terror,” and “The Great Galactic Ghoul” to illustrate their experiences, evidence of the anxiety that’s evoked by sending a robotic spacecraft to Mars — even among those who have devoted their careers to the task. But mention sending a human mission to land on the Red Planet, with payloads several factors larger than an unmanned spacecraft and the trepidation among that same group grows even larger. Why? Nobody knows how to do it.

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