Panorama

Karma: 303

Panorama 14 Aug 2016 10:35 UTC
2 points
on: Open Thread, Aug. 8 - Aug 14. 2016
Researchers orbit a muon around an atom, confirm physics is broken

The proton’s charge radius shouldn’t change, and yet it appears to.

Panorama 3 Aug 2016 10:37 UTC
6 points
on: Open Thread, Aug. 1 - Aug 7. 2016
Medical benefits of dental floss unproven

The federal government has recommended flossing since 1979, first in a surgeon general’s report and later in the Dietary Guidelines for Americans issued every five years. The guidelines must be based on scientific evidence, under the law.

Last year, the Associated Press asked the departments of Health and Human Services and Agriculture for their evidence, and followed up with written requests under the Freedom of Information Act.

When the federal government issued its latest dietary guidelines this year, the flossing recommendation had been removed, without notice. In a letter to the AP, the government acknowledged the effectiveness of flossing had never been researched, as required.

The AP looked at the most rigorous research conducted over the past decade, focusing on 25 studies that generally compared the use of a toothbrush with the combination of toothbrushes and floss. The findings? The evidence for flossing is “weak, very unreliable,” of “very low” quality, and carries “a moderate to large potential for bias.”

Panorama 13 Jun 2016 16:45 UTC
3 points
on: Open thread, Jun. 13 - Jun. 19, 2016
1,500 scientists lift the lid on reproducibility

Survey sheds light on the ‘crisis’ rocking research.

Full questionnaire

Raw data

Panorama 13 Jun 2016 16:23 UTC
2 points
on: Open thread, Jun. 13 - Jun. 19, 2016
University Innovation and the Professor’s Privilege by Hans K. Hvide, Benjamin F. Jones

National policies take varied approaches to encouraging university-based innovation. This paper studies a natural experiment: the end of the “professor’s privilege” in Norway, where university researchers previously enjoyed full rights to their innovations. Upon the reform, Norway moved toward the typical U.S. model, where the university holds majority rights. Using comprehensive data on Norwegian workers, firms, and patents, we find a 50% decline in both entrepreneurship and patenting rates by university researchers after the reform. Quality measures for university start-ups and patents also decline. Applications to literatures on university technology transfer, innovation incentives, and taxes and entrepreneurship are considered.

Panorama 21 Apr 2016 10:57 UTC
3 points
on: Open thread, Apr. 18 - Apr. 24, 2016
Related to Disguised Queries:

Concept Creep: Psychology’s Expanding Concepts of Harm and Pathology by Nick Haslam

Many of psychology’s concepts have undergone semantic shifts in recent years. These conceptual changes follow a consistent trend. Concepts that refer to the negative aspects of human experience and behavior have expanded their meanings so that they now encompass a much broader range of phenomena than before. This expansion takes “horizontal” and “vertical” forms: concepts extend outward to capture qualitatively new phenomena and downward to capture quantitatively less extreme phenomena. The concepts of abuse, bullying, trauma, mental disorder, addiction, and prejudice are examined to illustrate these historical changes. In each case, the concept’s boundary has stretched and its meaning has dilated. A variety of explanations for this pattern of “concept creep” are considered and its implications are explored. I contend that the expansion primarily reflects an ever-increasing sensitivity to harm, reflecting a liberal moral agenda. Its implications are ambivalent, however. Although conceptual change is inevitable and often well motivated, concept creep runs the risk of pathologizing everyday experience and encouraging a sense of virtuous but impotent victimhood.

Report about the paper in The Atlantic.

Panorama 3 Mar 2016 19:54 UTC
2 points
on: Open Thread Feb 29 - March 6, 2016
Cryptography Pioneers Receive 2015 ACM A.M. Turing Award

Whitfield Diffie, former Chief Security Officer of Sun Microsystems and Martin E. Hellman, Professor Emeritus of Electrical Engineering at Stanford University, are the recipients of the 2015 ACM A.M. Turing Award, for critical contributions to modern cryptography. The ability for two parties to communicate privately over a secure channel is fundamental for billions of people around the world. On a daily basis, individuals establish secure online connections with banks, e-commerce sites, email servers and the cloud. Diffie and Hellman’s groundbreaking 1976 paper, “New Directions in Cryptography,” introduced the ideas of public-key cryptography and digital signatures, which are the foundation for most regularly-used security protocols on the Internet today. The Diffie-Hellman Protocol protects daily Internet communications and trillions of dollars in financial transactions.

Panorama 12 Feb 2016 11:49 UTC
1 point
on: Open Thread, Feb 8 - Feb 15, 2016
Observation of Gravitational Waves from a Binary Black Hole Merger

This is the first direct detection of gravitational waves and the first observation of a binary black hole merger.

LIGO detects gravitational waves—Press Conference

Press Release

Panorama 6 Feb 2016 22:05 UTC
4 points
on: Open thread, Feb. 01 - Feb. 07, 2016
Winning Arguments: Interaction Dynamics and Persuasion Strategies in Good-faith Online Discussions by Chenhao Tan, Vlad Niculae, Cristian Danescu-Niculescu-Mizil, Lillian Lee.

Changing someone’s opinion is arguably one of the most important challenges of social interaction. The underlying process proves difficult to study: it is hard to know how someone’s opinions are formed and whether and how someone’s views shift. Fortunately, ChangeMyView, an active community on Reddit, provides a platform where users present their own opinions and reasoning, invite others to contest them, and acknowledge when the ensuing discussions change their original views. In this work, we study these interactions to understand the mechanisms behind persuasion. We find that persuasive arguments are characterized by interesting patterns of interaction dynamics, such as participant entry-order and degree of back-and-forth exchange. Furthermore, by comparing similar counterarguments to the same opinion, we show that language factors play an essential role. In particular, the interplay between the language of the opinion holder and that of the counterargument provides highly predictive cues of persuasiveness. Finally, since even in this favorable setting people may not be persuaded, we investigate the problem of determining whether someone’s opinion is susceptible to being changed at all. For this more difficult task, we show that stylistic choices in how the opinion is expressed carry predictive power.

Panorama 6 Feb 2016 22:02 UTC
1 point
on: Open thread, Feb. 01 - Feb. 07, 2016
Evaluating gambles using dynamics by Ole Peters, Murray Gell-Mann

Gambles are random variables that model possible changes in monetary wealth. Classic decision theory transforms money into utility through a utility function and defines the value of a gamble as the expectation value of utility changes. Utility functions aim to capture individual psychological characteristics, but their generality limits predictive power. Expectation value maximizers are defined as rational in economics, but expectation values are only meaningful in the presence of ensembles or in systems with ergodic properties, whereas decision-makers have no access to ensembles and the variables representing wealth in the usual growth models do not have the relevant ergodic properties. Simultaneously addressing the shortcomings of utility and those of expectations, we propose to evaluate gambles by averaging wealth growth over time. No utility function is needed, but a dynamic must be specified to compute time averages. Linear and logarithmic “utility functions” appear as transformations that generate ergodic observables for purely additive and purely multiplicative dynamics, respectively. We highlight inconsistencies throughout the development of decision theory, whose correction clarifies that our perspective is legitimate. These invalidate a commonly cited argument for bounded utility functions.

Panorama 21 Jan 2016 20:42 UTC
4 points
on: Open thread, Jan. 18 - Jan. 24, 2016
Evidence for a distant giant planet in the Solar System

Recent analyses have shown that distant orbits within the scattered disk population of the Kuiper Belt exhibit an unexpected clustering in their respective arguments of perihelion. While several hypotheses have been put forward to explain this alignment, to date, a theoretical model that can successfully account for the observations remains elusive. In this work we show that the orbits of distant Kuiper Belt objects (KBOs) cluster not only in argument of perihelion, but also in physical space. We demonstrate that the perihelion positions and orbital planes of the objects are tightly confined and that such a clustering has only a probability of 0.007% to be due to chance, thus requiring a dynamical origin. We find that the observed orbital alignment can be maintained by a distant eccentric planet with mass gsim10 m⊕ whose orbit lies in approximately the same plane as those of the distant KBOs, but whose perihelion is 180° away from the perihelia of the minor bodies. In addition to accounting for the observed orbital alignment, the existence of such a planet naturally explains the presence of high-perihelion Sedna-like objects, as well as the known collection of high semimajor axis objects with inclinations between 60° and 150° whose origin was previously unclear. Continued analysis of both distant and highly inclined outer solar system objects provides the opportunity for testing our hypothesis as well as further constraining the orbital elements and mass of the distant planet.

Panorama 15 Jan 2016 20:09 UTC
2 points
on: Open Thread, January 11-17, 2016
Why boredom is anything but boring

Implicated in everything from traumatic brain injury to learning ability, boredom has become extremely interesting to scientists.

Panorama 15 Jan 2016 20:01 UTC
0 points
on: Open Thread, January 11-17, 2016
Can Economics Change Your Mind?

Economics is sometimes dismissed as more art than science. In this skeptical view, economists and those who read economics are locked into ideologically motivated beliefs—liberals versus conservatives, for example—and just pick whatever empirical evidence supports those pre-conceived positions. I say this is wrong and solid empirical evidence, even of the complicated econometric sort, changes plenty of minds.

Can economics change your mind?

Where to start? I could write a whole ongoing blog on this question (wait…). In any case, here are just a few examples of where I have changed my mind due to economic evidence:

Panorama 6 Jan 2016 16:41 UTC
3 points
on: Open Thread, January 4-10, 2016
Iran’s blogfather: Facebook, Instagram and Twitter are killing the web

Hossein Derakhshan was imprisoned by the regime for his blogging. On his release, he found the internet stripped of its power to change the world and instead serving up a stream of pointless social trivia

Panorama 6 Jan 2016 16:04 UTC
3 points
on: Open Thread, January 4-10, 2016
Game Theory (Open Access textbook with 165 solved exercises) by Giacomo Bonanno.

Panorama 6 Jan 2016 16:01 UTC
15 points
on: Open Thread, January 4-10, 2016
Why too much evidence can be a bad thing

(Phys.org)—Under ancient Jewish law, if a suspect on trial was unanimously found guilty by all judges, then the suspect was acquitted. This reasoning sounds counterintuitive, but the legislators of the time had noticed that unanimous agreement often indicates the presence of systemic error in the judicial process, even if the exact nature of the error is yet to be discovered. They intuitively reasoned that when something seems too good to be true, most likely a mistake was made.

In a new paper to be published in The Proceedings of The Royal Society A, a team of researchers, Lachlan J. Gunn, et al., from Australia and France has further investigated this idea, which they call the “paradox of unanimity.”

“If many independent witnesses unanimously testify to the identity of a suspect of a crime, we assume they cannot all be wrong,” coauthor Derek Abbott, a physicist and electronic engineer at The University of Adelaide, Australia, told Phys.org. “Unanimity is often assumed to be reliable. However, it turns out that the probability of a large number of people all agreeing is small, so our confidence in unanimity is ill-founded. This ‘paradox of unanimity’ shows that often we are far less certain than we think.”

The researchers demonstrated the paradox in the case of a modern-day police line-up, in which witnesses try to identify the suspect out of a line-up of several people. The researchers showed that, as the group of unanimously agreeing witnesses increases, the chance of them being correct decreases until it is no better than a random guess.

In police line-ups, the systemic error may be any kind of bias, such as how the line-up is presented to the witnesses or a personal bias held by the witnesses themselves. Importantly, the researchers showed that even a tiny bit of bias can have a very large impact on the results overall. Specifically, they show that when only 1% of the line-ups exhibit a bias toward a particular suspect, the probability that the witnesses are correct begins to decrease after only three unanimous identifications. Counterintuitively, if one of the many witnesses were to identify a different suspect, then the probability that the other witnesses were correct would substantially increase.

The mathematical reason for why this happens is found using Bayesian analysis, which can be understood in a simplistic way by looking at a biased coin. If a biased coin is designed to land on heads 55% of the time, then you would be able to tell after recording enough coin tosses that heads comes up more often than tails. The results would not indicate that the laws of probability for a binary system have changed, but that this particular system has failed. In a similar way, getting a large group of unanimous witnesses is so unlikely, according to the laws of probability, that it’s more likely that the system is unreliable.

Panorama 16 Dec 2015 23:41 UTC
3 points
on: Open thread, Dec. 14 - Dec. 20, 2015
The science myths that will not die

False beliefs and wishful thinking about the human experience are common. They are hurting people — and holding back science.

Panorama 16 Dec 2015 23:40 UTC
3 points
on: Open thread, Dec. 14 - Dec. 20, 2015
The Strangest, Most Spectacular Bridge Collapse (And How We Got It Wrong)

Bridge building has been bedeviling humans for a long time, probably since the 1st century. That may explain why, even when they can’t carry lots of people or things, bridges are particularly good at carrying lots of meaning: breaking, burning, going too far, going nowhere; the bridges between cultures, across generations, the ones we’ll cross when we come to them. To this day, however, the meanings of Gertie’s collapse and that unforgettable footage—”among the most dramatic and widely known images in science and engineering,” wrote one engineer—remain murky.

For physics teachers, the footage of Gertie has proved irresistible as a lesson in wave motion—and, specifically, a textbook example of the power of forced resonance. The image of the undulating bridge left its mark on scores of students (including me) as a demonstration of what one canonical version of the film calls “resonance vibrations.” Since then, scores of books and articles, from Encyclopedia Britannica to a Harvard course website, have reported that the Tacoma Narrows was destroyed by resonance.

But it turns out it wasn’t. And yet, while science has known that for years, lots of people (including me) apparently didn’t get the memo.

Panorama 16 Dec 2015 23:23 UTC
16 points
on: Open thread, Dec. 14 - Dec. 20, 2015
Guess the correlation

The aim of the game is simple. try to guess how correlated the two variables in a scatter plot are. The closer your guess is to the true correlation, the better.

Panorama 16 Dec 2015 23:20 UTC
0 points
in reply to: Panorama’s comment on: Open thread, December 7-13, 2015
Ask an unbounded question, get an uncomputable answer by Scott Aaronson

Panorama 16 Dec 2015 23:13 UTC
3 points
on: Open thread, Dec. 14 - Dec. 20, 2015
Notes on the Oxford IUT workshop by Brian Conrad

Since he was asked by a variety of people for his thoughts about the workshop, Brian wrote the following summary. He hopes that a non-specialist may also learn something from these notes concerning the present situation. Forthcoming articles in Nature and Quanta on the workshop will be addressed at the general public. This writeup has the following structure:

Background

What has delayed wider understanding of the ideas?

What is Inter-universal Teichmuller Theory (IUTT = IUT)?

What happened at the conference?

Audience frustration

Concluding thoughts

Technical appendix