👓 Mutating DNA caught on film | Science | AAAS

Mutating DNA caught on film by Elizabeth Pennisi (Science | AAAS)
Study in bacteria shows how regularly DNA changes and how few of those changes are deadly

This is a rather cool little experiment.

h/t to @moorejh via Twitter:

Bookmarked on March 16, 2018 at 12:15PM

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🔖 Efficient Algorithms for Searching the Minimum Information Partition in Integrated Information Theory

Efficient Algorithms for Searching the Minimum Information Partition in Integrated Information Theory by Jun Kitazono, Ryota Kanai, Masafumi Oizumi (MDPI)
The ability to integrate information in the brain is considered to be an essential property for cognition and consciousness. Integrated Information Theory (IIT) hypothesizes that the amount of integrated information ( Φ ) in the brain is related to the level of consciousness. IIT proposes that, to quantify information integration in a system as a whole, integrated information should be measured across the partition of the system at which information loss caused by partitioning is minimized, called the Minimum Information Partition (MIP). The computational cost for exhaustively searching for the MIP grows exponentially with system size, making it difficult to apply IIT to real neural data. It has been previously shown that, if a measure of Φ satisfies a mathematical property, submodularity, the MIP can be found in a polynomial order by an optimization algorithm. However, although the first version of Φ is submodular, the later versions are not. In this study, we empirically explore to what extent the algorithm can be applied to the non-submodular measures of Φ by evaluating the accuracy of the algorithm in simulated data and real neural data. We find that the algorithm identifies the MIP in a nearly perfect manner even for the non-submodular measures. Our results show that the algorithm allows us to measure Φ in large systems within a practical amount of time.

h/t Christoph Adami, Erik Hoel, and @kanair

🔖 Black hole explosions? by Stephen Hawking | Nature

Black hole explosions? by Stephen Hawking (Nature)
QUANTUM gravitational effects are usually ignored in calculations of the formation and evolution of black holes. The justification for this is that the radius of curvature of space-time outside the event horizon is very large compared to the Planck length (Għ/c3)1/2 ≈ 10−33 cm, the length scale on which quantum fluctuations of the metric are expected to be of order unity. This means that the energy density of particles created by the gravitational field is small compared to the space-time curvature. Even though quantum effects may be small locally, they may still, however, add up to produce a significant effect over the lifetime of the Universe ≈ 1017 s which is very long compared to the Planck time ≈ 10−43 s. The purpose of this letter is to show that this indeed may be the case: it seems that any black hole will create and emit particles such as neutrinos or photons at just the rate that one would expect if the black hole was a body with a temperature of (κ/2π) (ħ/2k) ≈ 10−6 (M⊙/M)K where κ is the surface gravity of the black hole1. As a black hole emits this thermal radiation one would expect it to lose mass. This in turn would increase the surface gravity and so increase the rate of emission. The black hole would therefore have a finite life of the order of 1071 (M⊙/M)−3 s. For a black hole of solar mass this is much longer than the age of the Universe. There might, however, be much smaller black holes which were formed by fluctuations in the early Universe2. Any such black hole of mass less than 1015 g would have evaporated by now. Near the end of its life the rate of emission would be very high and about 1030 erg would be released in the last 0.1 s. This is a fairly small explosion by astronomical standards but it is equivalent to about 1 million 1 Mton hydrogen bombs.

In honor of pi day and the passing of Stephen Hawking, here’s one of his seminal papers published just before I was born.

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🔖 [1803.03443] Fake news propagate differently from real news even at early stages of spreading

Fake news propagate differently from real news even at early stages of spreading by Zilong Zhao, Jichang Zhao, Yukie Sano, Orr Levy, Hideki Takayasu, Misako Takayasu, Daqing Li, Shlomo Havlin (arxiv.org)
Social media can be a double-edged sword for modern communications, either a convenient channel exchanging ideas or an unexpected conduit circulating fake news through a large population. Existing studies of fake news focus on efforts on theoretical modelling of propagation or identification methods based on black-box machine learning, neglecting the possibility of identifying fake news using only structural features of propagation of fake news compared to those of real news and in particular the ability to identify fake news at early stages of propagation. Here we track large databases of fake news and real news in both, Twitter in Japan and its counterpart Weibo in China, and accumulate their complete traces of re-posting. It is consistently revealed in both media that fake news spreads distinctively, even at early stages of spreading, in a structure that resembles multiple broadcasters, while real news circulates with a dominant source. A novel predictability feature emerges from this difference in their propagation networks, offering new paths of early detection of fake news in social media. Instead of commonly used features like texts or users for fake news identification, our finding demonstrates collective structural signals that could be useful for filtering out fake news at early stages of their propagation evolution.
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The Physics of Life: Summer School | Center for the Physics of Biological Function

The Physics of Life: Summer School | Center for the Physics of Biological Function (biophysics.princeton.edu)
A summer school for advanced undergraduates June 11-22, 2018 @ Princeton University What would it mean to have a physicist’s understanding of life? How do DYNAMICS and the EMERGENCE of ORDER affect biological function? How do organisms process INFORMATION, LEARN, ADAPT, and EVOLVE? See how physics problems emerge from thinking about developing embryos, communicating bacteria, dynamic neural networks, animal behaviors, evolution, and more. Learn how ideas and methods from statistical physics, simulation and data analysis, optics and microscopy connect to diverse biological phenomena. Explore these questions, tools, and concepts in an intense two weeks of lectures, seminars, hands-on exercises, and projects.
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Gary Posner obituary

Renowned chemist, longtime Hopkins faculty member Gary Posner dies at 74 (The Hub (JHU))
Gary Posner, best known for pioneering research in organocopper chemistry, joined JHU faculty in 1969

I should know better about searching for obituaries. After hearing about Murray Sach’s passing I’ve just discovered that one of my organic chemistry professors has recently died as well.

I remember Dr. Posner well for his pointed use of the Socratic method, and in particular the day that my chemistry-related sir name caught his eye. I think he always expected that I would have been born a chemistry genius because of the name Aldrich. His expectations did make my orgo studies all the more fraught and worthwhile however.

I will point out in my day that the reaction that carried his name was ordered as the Corey-Posner-Whitesides-House reaction and not in the lesser order mentioned in the article.

Murray Sachs Obituary

Murray Sachs Obituary - Brookline, MA (Dignity Memorial)
Murray Sachs, of Arlington, MA, formerly of Baltimore, MD, on Saturday, March 3, 2018. Beloved husband of the late Merle (Diener) Sachs. Devoted father of Benjamin Sachs & his wife Lisa, and Jonathan Sachs & his wife Kate. Loving grandfather of Talia, Aviva, Zoe, Zander, Jonah, and Miriam. Loving uncle of Nancy Colier and Steven Shainberg. Murray was a renowned scientist who received his undergraduate and graduate degrees in electrical engineering from MIT (B.S. ’62, M.S. ‘64, Ph.D. ‘66). He worked in the field of biomedical engineering, in particular using mathematics to model the way sound is received, transmitted, encoded, and comprehended between the ear and the brain, laying groundwork for advances such as the cochlear implant. He served as the Director of the Biomedical Engineering Department at Johns Hopkins University. Murray was elected a member of the Institute of Medicine of the National Academy of Sciences, and a member of the National Academy of Engineering for his scientific contributions and his leadership in biomedical engineering education. Murray is remembered as having a gentle soul, and as being a calm leader and generous mentor. He was a loving husband, beloved father, doting grandfather, and a deeply devoted colleague and friend. He will be profoundly missed. Services at Temple Beth Avodah, 45 Puddingstone Lane, Newton, MA on Monday, March 5 at 2pm. In lieu of flowers, remembrances may be made to Michael J. Fox Foundation for Parkinson’s Research.

Saddened to hear about the passing of one of my college professors and a lion in the field of biomedical engineering. I’ve heard that there are forthcoming obituaries in the JHU Hub as well as the Baltimore Sun.

h/t to Guy Shechter for passing along the news

🔖 Gentle Reader – Read Match Discover

Gentle Reader (gentlereader.com)
Gentle Reader gives you the freshest content in an easy-to-read format with no clutter and no ads. Add your favourite websites and Twitter accounts or discover new articles by exploring what other readers are bookmarking based on your interests. That way you can save time and hassle by efficiently combining RSS feeds, Twitter feeds, bookmarking and read-later services all in one app. What's more you have complete control over if, when, and how you discover new information with our unique matching function.

This is an interesting looking app. Sadly no Android version yet, so I’m taking a peek at it on the web. An interesting melange of features, but certainly not perfect for my needs yet. Has some interesting discovery type tools, but I’ll need to dig in further to test these out.

One of their default feeds, while solid, appears to only allow a synopsis sentence or two instead of the full feed, so it’s not the best example for the site to feature.

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