- Methane hydrates will be the new shale gas. There is perhaps an order of magnitude more methane worldwide in hydrates than in shale deposits, but it’s harder to extract. “…it’s thought that only by 2025 at the earliest we might be able to look at realistic commercial options.”
Sperm whales have no (external) teeth on their upper jaw, which instead features holes into which the teeth on their narrow lower jaw fit.
- Surprising and heartening to me: GiveWell finds that distributing antiretroviral therapy drugs to HIV positive patients (presumably in developing countries) is potentially cost-effective compared to their top recommendations.
- Relatedly: the general flow of genetic information is DNA->RNA->protein. At a crude level, viruses are classified as either RNA viruses or DNA viruses depending on what sort of genetic material they carry. Generally, as parasites dependent on the host cell machinery, this determines where in the protein construction process they inject their payload. However, retroviruses (like HIV) are RNA viruses that bring along their own reverse transcriptase enzyme that, once inside the cell, converts their payload back into DNA and then grafts it into the host’s genome (which is then copied as part of the host cell’s lifecycle). Once this happens, it is very difficult to tell which cells have been infected and very difficult to root out the infection.
I remember reading about the common pitfalls of vertically integrated companies when I was in school. While there are usually some compelling cost savings to be had from vertical integration (either through insourcing services or acquiring suppliers/customers), the increased margins typically evaporate over time as the “supplier” gets complacent with a captive, internal “customer.”
There are great examples of this in the automotive industry, where automakers have gone through alternating periods of supplier acquisitions and subsequent divestitures as component costs skyrocketed. Divisions get fat and inefficient without external competition. Attempts to mitigate this through competitive/external bid comparison, detailed cost accountings and quotas usually just lead to increased bureaucracy with little effect on actual cost structure.
The most obvious example of Amazon’s SOA structure is Amazon Web Services (Steve Yegge wrote a great rant about the beginnings of this back in 2011). Because of the timing of Amazon’s unparalleled scaling — hypergrowth in the early 2000s, before enterprise-class SaaS was widely available — Amazon had to build their own technology infrastructure. The financial genius of turning this infrastructure into an external product (AWS) has been well-covered — the windfalls have been enormous, to the tune of a $14 billion annual run rate. But the revenue bonanza is a footnote compared to the overlooked organizational insight that Amazon discovered: By carving out an operational piece of the company as a platform, they could future-proof the company against inefficiency and technological stagnation.
In the 10+ years since AWS’s debut, Amazon has been systematically rebuilding each of its internal tools as an externally consumable service. A recent example is AWS’s Amazon Connect — a self-service, cloud-based contact center platform that is based on the same technology used in Amazon’s own call centers. Again, the “extra revenue” here is great — but the real value is in honing Amazon’s internal tools…
The key advantage that Amazon has over any other enterprise service provider — from UPS and FedEx to Rackspace — is that they are forced to use their own services. UPS is a step removed from backlash due to lost/destroyed packages, shipping delays, terrible software and poor holiday capacity planning. Angry customers blame the retailer, and the retailer screams at UPS in turn. When Amazon is the service provider, they’re permanently dogfooding. There is nowhere for poor performance to hide. Amazon has built a feedback loop as a moat, and it is incredible to watch the flywheel start to pick up speed.
In mammals, the esophagus and trachea are straight and symmetric, running vertically down the ventral and dorsal side of the throat, respectively. But these tubes are asymmetric in birds.
- Bryan Caplan: The more you (probably correctly) think that geography trumps institution quality and ancestry for determining economic prosperity, the more you should support freer immigration. And this might even make the geo-determinist a optimist, rather than a fatalist, since migration policy is arguably much more tractable than changing people’s genes or re-structuring their society.
Paul Graham has a classic essay on “the submarine“, the ubiquitous but surprisingly poorly known practice where news outlets are directly fed stories from the people and organizations who stand to benefit from them, especially with the appropriate spin. (The incentive for the news reporter is that they don’t have to do any actual news gathering, which is expensive and time consuming.) The recent story fed to Engadet reporter David Lumb by the Fraunhofer Institute about the expiration of their MP3 patent is a spectacularly transparent, and hence pedagogical, example. Due to this expiration, the Fraunhofer Institute can no longer collect money from licensing the format, so it is in their interest to move people towards the formats they can (AAC). The MP3 format is now fully unencumbered, which is an obvious boost to it’s value to consumers, but the headline is “MP3 is dead. Long live AAC.” No mention of the expiration of the patent, just a report that the Institute is no longer issuing licenses! You might think this is just an issue with low-quality tech journalism like Engadet, but unfortunately even NPR is syndicating these types of stories:
So is it the end of an era? We may still use MP3s, but when the people who spent the better part of a decade creating it say the jig is up, we should probably start paying attention. AAC is indeed much better — it’s the default setting for bringing CDs into iTunes now — and other formats are even better than it, though they also take up mountains of space on our hard drives.
(That story also, incredibly, fails to mention that the patent expired.) The broader point, of course, is that the news is filled with these sorts of submarine stories, just generally a bit more concealed.
- Popehat on the farcical nature of Federal plea bargain hearings. This general phenomenon rings very true to me. At a NM state court I saw an uneducated man who was being instructed by the judge to sign something as part of a plea deal the man didn’t think was a fair description of the incident. The judge threatened to dramatically increase the punishment if the man didn’t sign right at that moment while simultaneously telling him that signing anything that wasn’t exactly true was criminal perjury. It was so dysfunctional.
- Transcript and bullet point summary of SpaceX’s Tom Mueller’s Skype call.
- Video of Narwhals using their tusks to hunt. I hadn’t known that tusks are innervated, unlike antlers, although this makes sense since tusks evolved from teeth. Elephant tusks are also living, and can heal, but have minimal feeling.
A classic, accessible introduction to the Turbo Encabulator:
A large counterexample:
In mathematics, the Mertens conjecture is the false statement that the Mertens functionM(n) is bounded by √n, which implies the Riemann hypothesis.
It was later shown that the first counterexample appears below () (Pintz 1987) but above (100 trillion).
- Microsoft paint as a serious artistic medium.
Spectacularly fossilized dinosaur found in Canada. Non-trivial to recover:
For more than 7,000 hours over the past five years, Mitchell has slowly exposed the fossil’s skin and bone. The painstaking process is like freeing compressed talcum powder from concrete. “You almost have to fight for every millimeter,” he says.
Hey, I’m the journalist who wrote the story. A few things: – The organic-rich film preserving the outlines of scales (so, yes, fossilized skin) is only a few millimeters thick. So Mitchell had to prepare the fossil extremely slowly in order to follow the film through the matrix. – The half-life of DNA is ~521 years at 13.1°C, as found in this 2012 paper: http://rspb.royalsocietypublishing.org/content/279/1748/4724 The team’s model predicts higher half-lifes at truly freezing temperatures, but even at the extreme end, there’s no way DNA would survive 110 million years. – The dating on the site is well constrained to ~110 million years old. The fossil was found in the Wabiskaw Member of the Clearwater Formation, a well-dated rock formation in Alberta. The underlying oil sands have been radiometrically dated to 112±5.3 million years old. (http://science.sciencemag.org/content/308/5726/1293)
- On the historical change in algorithmic compressibility of pop music lyrics.
- The need for side underride guards on tractor trailers.
- Physics Today covers the depressing prospect that no one wants to spend the money to build a machine with even an order of magnitude improvement to the LHC, but we may keep the field of particle physics on life support for at least another decades by augmenting the LHC with an electron accelerator and a proton-electron collision point. (H/t Peter Woit.)
- Accessible update on the hunt for Planet Nine.
Striking video of a lion having a convulsive seizure.
This is apparently a wild lion and there’s no indication of what happened after this, but at least in humans “most seizures last from 30 seconds to 2 minutes and do not cause lasting harm”.
- 80k Hours nicely describes some great data on salary by industry. I was surprised to see that doctor mean salary edges out finance and law.
Several people linked to this WSJ article on possible collusion between dynamical, price-setting algorithms. This was to me the most striking part:
In one example of what can happen when prices are widely known, Germany required all gas stations to provide live fuel prices that it shared with consumer price-comparison apps. The effort appears to have boosted prices between 1.2 to 3.3 euro cents per liter, or about 5 to 13 U.S. cents per gallon, according to a discussion paper published in 2016 by the Düsseldorf Institute for Competition Economics.
Plausibly, the key fact is that the systems — “AI”s, although not really — gather lots of historical information about how their competitors react to price changes, opening a potential line of communication between the AIs. This makes it feasible, and perhaps likely, that the AI’s may settle on a game-theoretic equilibrium where they both “agree” to keep prices high because some earlier tit-for-tat behavior. It would be great to see a toy model of this explicitly. Here was another neat anecdote:
One client called to complain the software was malfunctioning. A competitor across the street had slashed prices in a promotion, but the algorithm responded by raising prices. There wasn’t a bug. Instead, the software was monitoring the real-time data and saw an influx of customers, presumably because of the long wait across the street.
“It could tell that no matter how it increased prices, people kept coming in,” said Mr. Derakhshan.
- IvanFyodorovich at SlateStarCodex reports that the CDC disagrees with the AEI claim that US leads in life expectancy once violent deaths are removed (reported at this blog in last month’s links). As usual, things quickly become murky once you dive into the details, but IvanFyodorovich’s analysis is the most detailed and convincing I know of. Although violent crime in the US accounts for perhaps half of the gap between the US and other wealthy countries — and hence must be considered in all arguments that attempt to draw conclusions about healthcare from the existence of this gap — trying to explain the entire gap requires (at least) statistical gymnastics.
My summary of Robin Hanson’s argument against the feasibility of Mars colonization for the forceable future:
The things to note are (1) Self-sufficient colonies in Antarctica or under the ocean would be much easier than Mars. (2) Many of the key technologies of our civilization only make sense at scale (100’s of millions of humans) and with access to cheap resources (e.g., water). The economy is highly interdependent so that each resource you take away forces you to solve many surprising new problems. (Most of these things are heavy and cannot be continuously shipped from Earth to Mars.) (3) Humans do not go places because it’s a great story, they largely go there for economic rewards, and in particular, they rarely leave places they are wealthy to go to places where they become dirt poor.
The Vikings had the transportation technology to get to the New World many centuries before there were persistent European colonies, and this was in a time when the economy was much less dependent on the cooperation of large numbers of humans and many kinds of resources from diverse places. Our current era is much more analogous to 900 AD than 1492.
On the unusual growth of staff in the Wikimedia foundation (my bold):
In 2005, Wikipedia co-founder and Wikimedia Foundation [WMF] founder Jimmy Wales told a TED audience:
So, we’re doing around 1.4 billion page views monthly…. And everything is managed by the volunteers and the total monthly cost for our bandwidth is about US$5,000, and that’s essentially our main cost. We could actually do without the employee … We actually hired Brion because he was working part-time for two years and full-time at Wikipedia so we actually hired him so he could get a life and go to the movies sometimes.
According to the WMF, Wikipedia (in all language editions) now receives 16 billion page views per month. The WMF spends roughly US$2 million a year on Internet hosting and employs some 300 staff. The modern Wikipedia hosts 11–12 times as many pages as it did in 2005, but the WMF is spending 33 times as much on hosting, has about 300 times as many employees, and is spending 1,250 times as much overall. WMF’s spending has gone up by 85% over the past three years.
Sounds a lot like cancer, doesn’t it? For those readers who were around three years ago, did you notice at the time any unmet needs that would have caused you to conclude that the WMF needed to increase spending by $30 million dollars? I certainly didn’t.
The large majority of funds donated to WMF are not spent on hosting, overhead, or other things necessary for the normal function of the site. See the HN comments for a rebuttals to the author’s claim that WMF’s software development team lacks a roadmap and goals/specifications (although pretty much everyone seems to agree the software output has been subpar).
- Cormac McCarthy’s essay on the biological origins of language has lots of neat tidbits, like the fact that dolphins simply die if they are anesthesized because their breathing behavior (coming above water for air) requires conscious control, and so is never handled by the brainstem alone like it often is in land mammals.
I had heard there exist small planes for private pilots that have a parachute for the whole plane, but I did not know that one of them, the Cirrus SR22, has been “the world’s best-selling general aviation airplane every year since 2002” and accounts “for over 30% of the entire piston aircraft market”. In fact, the plane can sometimes even be reused after deploying and landing with the parachute!
As of 15 August 2016, the CAPS [Cirrus Airframe Parachute System] has been activated 83 times, 69 of which saw successful parachute deployment. In those successful deployments, there were 142 survivors and 1 fatality. No fatalities, unsuccessful deployments, or anomalies (with the exception of one that is still under investigation) have occurred when the parachute was deployed within the certified speed and altitude parameters. Some additional deployments have been reported by accident, as caused by ground impact or post-impact fires, and 14 of the aircraft involved in CAPS deployments have been repaired and put back into service.
Qualifies as a great landing.
chris_va on geothermal and efficient well markets:
Conventional geothermal is about 4-5 cents/kWh, on par with natural gas in the US. The dominant capital cost is drilling a large well (you need volume), and so geothermal plants are generally only built in areas that require shallow (1km) wells.
Well costs are ~quadratic in depth. Given how much money has already been spent optimizing drilling for the oil&gas industry, along with how cutthroat that market is, I don’t see the cost coming down significantly. As a result, deep geothermal will likely be limited to niche regions like Iceland. And you need deep geothermal to scale it past the existing locations.
I would love to be wrong, since geothermal checks all the boxes for renewables and is also suitable for base load power, but I don’t see an obvious path forward short of a drilling tech miracle.
GoPro view inside the nest of rattlesnakes.
Mapping the connectome of C. elegans is not overwhelmingly illuminating.
“I think it’s fair to say…that our understanding of the worm has not been materially enhanced by having that connectome available to us. We don’t have a comprehensive model of how the worm’s nervous system actually produces the behaviors. What we have is a sort of a bed on which we can build experiments—and many people have built many elegant experiments on that bed. But that connectome by itself has not explained anything.”
It is, however, a very useful starting point
In the 1980s, as a postdoctoral student in Brenner’s lab, Martin Chalfie—now at Columbia University—used the C. elegans wiring diagram to explain one of the worm’s behaviors: He identified the specific neural circuits responsible for the worm’s tendency to wriggle backward when poked on the head and to squirm forward when touched on the tail. “The connectome was absolutely critical,” Chalfie says. “Without it, we simply would not have known which cells were connected to which.” By combining the wiring diagram with evidence from previous research, Chalfie predicted that a particular set of interneurons mediated forward movement and that another was involved in backward movement. Annihilating those neurons with lasers confirmed his predictions.
Check out the worm atlas.
- If you are frustrated cleaning up copy-pasted text (e.g., removing extra line breaks, fixing double spaces, tabs to space, etc.) and you use OSX, then get Clean Text Menu. Pretty slick.
- Steve Hsu covers a new proposal for improving replicability.
As part of our research on the history of philanthropy, I recently investigated several case studies of early field growth, especially those in which philanthropists purposely tried to grow the size and impact of a (typically) young and small field of research or advocacy.
The full report includes brief case studies of bioethics, cryonics, molecular nanotechnology, neoliberalism, the conservative legal movement, American geriatrics, American environmentalism, and animal advocacy. My key takeaways are:
- Most of the “obvious” methods for building up a young field have been tried, and those methods often work. For example, when trying to build up a young field of academic research, it often works to fund workshops, conferences, fellowships, courses, professorships, centers, requests for proposals, etc. Or when trying to build up a new advocacy community, it often works to fund student clubs, local gatherings, popular media, etc.
- Fields vary hugely along several dimensions, including (1) primary sources of funding (e.g. large philanthropists, many small donors, governments, companies), (2) whether engaged philanthropists were “active” or “passive” in their funding strategy, and (3) how much the growth of the field can be attributed to endogenous factors (e.g. explicit movement-building work) vs. exogenous factors (e.g. changing geopolitical conditions).
Some good discussion in the HN thread about the incredible growth of Vanguard, especially regarding the collusional and system-wide dangers introduced as passive investing becomes dominant. Here are two ideas for ways to mitigate this issue while retaining most of the vast benefits of index funds:
- A major institution (e.g. Vanguard) holds index funds, but the shareholder voting for each company in those funds is done by a different in-house team whose compensation is tied to the performance of that particular company. (More realistically, you’d just need a different team for each company in a given industry, but one team could vote for multiple companies that don’t compete with each other.) It’s “passive investing with active shareholder governance” in the sense that only voting, not dollars, are actively directed.
- Accelerate the trend of issuing two classes of stock, with and without voting rights. Only active investors and corporate raiders bother to pay a premium for influence.
Although obvious in retrospect, it would not have occurred to me that this was possible (and pretty easy) given that diesel and methane are in different states:
Existing gasoline-powered vehicles may be converted to run on CNG [compressed natural gas] or LNG [liquid natural gas], and can be dedicated (running only on natural gas) or bi-fuel (running on either gasoline or natural gas). Diesel engines for heavy trucks and busses can also be converted and can be dedicated with the addition of new heads containing spark ignition systems, or can be run on a blend of diesel and natural gas, with the primary fuel being natural gas and a small amount of diesel fuel being used as an ignition source.
I knew people talked about how there are many agricultural workers that are working in the US illegally, but I did not have a sense of the scale:
The share of hired crop farmworkers who were not legally authorized to work in the U.S. grew from roughly 15 percent in 1989-91 to almost 55 percent in 1999-2001. Since then it has fluctuated around 50 percent. Since 2001, the share who are citizens has increased from about 21 percent to about 33 percent, while the share who hold green cards or other forms of work authorization has fallen from about 25 percent to about 19 percent.
adulthood is emailing “sorry for the delayed response!” back and forth until one of you dies’
(H/t Rob Wiblin.)
- Paul Graham on the increasing number and kind of addictive things.
Brian Shul is the Vietnam veteran and SR-71 pilot responsible for the widely internet-famous story about “the ground speed check”. He gives a pretty good inspirational speech, and he has that wholesome swagger that is rare in later generations.
The speed check story is at 56:29, although I think the written version is better. I also didn’t know that Shul’s partner Walter L. Watson Jr., who is the hero of the story, was the only African American who flew the SR-71.
In dueling, signaling and game theory run deep:
Delope…is the practice of throwing away one’s first fire in a pistol duel, in an attempt to abort the conflict. According to most traditions, the deloper must first allow his opponent the opportunity to fire after the command (“present”) is issued by the second, without hinting at his intentions…
The delope could be attempted for practical reasons, such as if one duelist thought their opponent was superior in skill, so as not to provoke a fatal return shot. Deloping could also be done for moral reasons if the duelist had objections to attempting to kill his opponent or if he were so skilled a marksman as to make the exchange unfair. Deloping in a duel, for whatever reason, could be a risky strategy whether or not the delope was obvious to all present. Deloping with a near miss, in order to save one’s honor without killing, could backfire if the opponent believed the effort to be genuine and responded with a fatal shot. Also, regardless of whether the delope was near or wide, the opponent might infer that he was being insulted as “not worth shooting” (an unworthy opponent) and either take care to aim his own shot to kill or insist on a second exchange.
However, for the opponent to insist upon a second shot after a delope was considered bloodthirsty and unbecoming. Often, it would fall to the seconds to end the duel immediately after a delope had been observed.
The term delope is specific to the use of firearms in a duel which, historically speaking, were typically flintlock pistols. These pistols were notorious for their lack of accuracy at long distances and a particularly skilled marksman might attempt to delope unnoticed with a well-placed “near-miss.” The distance between the two combatants had to be great enough that all others present would assume that any miss was due to this inherent inaccuracy and not intentional. This way the shooter could avoid killing his opponent and, if accused of deloping, claim he had made a genuine effort. Also, the opponent might recognize the “near-miss” as a delope but understand that it was meant for the benefit of any witnesses present and, if the opponent was not insulted, also delope. Both parties could then claim they had each tried to shoot the other and the duel would end without any fatalities.
And this is just one aspect of the actual duel itself. Just imagine the amount of additional social structure that would arise in societies with dueling.
- Chris Ferrie now making his referee reports public on GitHub. Here’s his first one. Although it’s possible to imagine ways this could be bad if it gets popular, I think, on the whole, more of this is likely to be very good. Because of demands on time, expert assessment is a very scarce resource. You can arguably blame a lot of pathologies in academia on it; the reason hiring and grant committee use game-able citation metrics is because it’s too hard and time-consuming to actually read and understand the work of applicants. Given this, it’s sort of crazy that the most careful assessment that most papers ever receive is thrown away, never to be used by anyone ever again. Only a single bit of information about the paper leaks out — that it was published in that particular journal — with zero information if it’s rejected.
The recent SpaceX launch of the classified NRO satellite is the first launch with video coverage from the ground for the entire first-stage flight, and it is spectacular. See especially the first-stage separation and boost-back burn:
as well as the unpowered rocket plummeting at 20:20 and the landing burn at 20:35. (Or go here or here for the GIFs, and here for musical accompaniment.)
- Orbital rockets are getting smaller. This recent one (which failed) was 30 feet tall and 18 inches wide, with a 3 kg cubesat payload.
- N-gate, HN satire. (H/t Perry Metzger.)
- “Sorting 2 Metric Tons of Lego“. He answers a ton of questions in detail in the HN discussion.
- Anagram scoring.
- Video of private plane landing while missing one tire.
Transcript of a good interview with Drew Houston, the founder of Dropbox. He’s one of the few people who I’d take recommendations from on management books.
I think my favorite book on management is “High Output Management” by Andy Grove, which is kind of the Bible of how do you scale an organization. I have a very long list of recommendations. “The Effective Executive” by Peter Drucker is really good. But basically what you’re talking about is, you need to have good judgment about a lot of different things. What that really is saying is, how do you gain wisdom really quickly? Last book recommendation, “Poor Charlie’s Almanack” by Charlie Munger. This is probably the best book on that that I’ve read, which is really about how do you build a bunch of mental models to break down the complexity of the world and know when to use each.
avn2109 on the room for improvement in tunnel boring machines (TBMs):
There is a ton of room for innovation around tunnel boring machines built by the major manufacturers (primarily Herrenknecht and Robbins), around reliability, durability, ease of serviceability etc. I cannot emphasize enough how modern TBM’s require an unbelievable amount of engineering attention, repair labor, spare parts infrastructure etc, similar to many super-early-stage fragile prototype technologies. Unfortunately TBM’s are no longer early stage, but for some reason the technology is frozen at just-good-enough-to-barely-work.”
However I don’t know if the economics will work out to fix any of these. Here are a couple of the big problems:
- Most TBM’s are semi- or fully-customized for a single job. This raises machine costs. It’d be better if there were only a small range of small-medium-large TBM’s that work ~everywhere.
- Most TBM’s are fully assembled in the factory, smoketested aka turned on to make sure they work, disassembled and shipped to the job, then reassembled and used. This is not efficient, surely we can figure out a better way.
- Most TBM’s are entombed aka thrown away at the end of the job, because getting them out of the hole is expensive and difficult.
- Changing the cutterheads is labor intensive and dangerous and requires highly trained very expensive humans, and it’s slow. While you change the cutterheads, your billion dollar toy is sitting there doing nothing.
- TBM architecture is highly dependent on geology. A slurry faced TBM that works in mixed soils is a totally different beast from a hard-rock TBM. It would be cool to have one machine that works in many geologies, perhaps with minimal or automated modifications.
- TBM’s require lots of care and feeding from a small army of humans. This raises job costs.
- Topside support infrastructure such as slurry plants and ground freezing machinery comes from different vendors, often even from different countries. E.g. it’s common to buy your topside slurry plant from the MS company, in France, while your ground freeze vendor might be Tachibana from Japan. Often each subsystem’s engineers on site literally don’t even speak a common language. Hilarity predictably ensues. Vertical integration would pay huge dividends here.
Ideally Elon can mass-produce TBM’s that just work out of the box for most jobs, and that are easier to work on. Then we can laugh him out of town for his stupid “put cars in tunnels” ideas and use his miracle machines to build sensible train tunnels.
Lots of parallels with the rocket industry.
Another good video on fusion energy designs from MIT, arguing that newer high-temperature superconductors should allow one to avoid the huge organizational inefficiencies of building experiments the size of ITER. Starts out very elementary, but helpfully enumerates many of the possible approaches to fusion.
The plot of fusion triple product as a function of time at 43:45 is depressing.
Chad Orzel is skeptical that the situation with high-energy theorists chasing fadish ideas unconstrained by experiment is avoidable.
With no new data coming in, what else can they do? He thinks the Maverick advice to “think wider, more unconventional” is fine but limited in possible impact.
My suggestion, on which I have much to write in the future, is that theorists should get their house in order: distill what is known in a single authoritative place. It should incorporate the best mechanisms from the Review of Particle Physics, Reviews of Modern Physics, the Stanford Encyclopedia of Philosophy, Wikipedia, and GitHub, and would require developing much more powerful tools for collaboration and dispute resolution than we have now, eventually with great value to other fields.
- APS and CERN agree to make all CERN research articles in APS journals open access and, much more importantly in my opinion, free for reuse and adaptation (with attribution).
Tyler Cowen on topics near climate change that should be studied better:
…how good is the social science in this area? I would say “not so great.” Try looking for good public choice treatments of how climate intentions end up translated into climate policy. That is a remarkably important question, and yet it is understood poorly.
Or “how many of the people who make proclamations in this area have a decent understanding of Chinese energy and climate policy?”, and the answer is hardly any, even though that may be the most important topic in the area. And I ask that question not only of the casual tweeters but also of the academics who work on climate change.
By way of Cowen, this excellent, painful essay by art critic Jerry Saltz on his initial failed career as an artist. And photos of white ravens. (The have leucism.)
And a game theoretic (and idealistic) analysis of the North Korean nuclear situation.
Cable-stay bridges have grown quickly in popularity because “Improvements in stress tolerance, corrosion resistance and computer modeling [have allowed them to be built] cheaper and more efficiently” for medium-size spans (“between 150 and 915 meters”). See especially the Octávio Frias de Oliveira Bridge in São Paulo, which is “the only bridge in the world that has two curved tracks supported by a single concrete mast”:
The difference from suspension bridges:
In a suspension structure such as the Golden Gate Bridge primary cables are strung from tower to tower and secondary cables drop down from those to hold the roadbed in place. Cable-stayed bridges, by contrast, have cables that run directly from the tower to the road. They essentially eliminate the cables between towers.
But the longest spans still go for suspension:
Cable-stay is inadvisable for bridges with a main span longer than 915 meters because the towers would have to soar twice as high as the towers of a suspension bridge of the same length to string enough cables to hold the road deck in place. For very long bridges, traditional suspension wins out.
- Fermat’s library this week is a good Scientific American on the measurement discrepancies for the free neutron lifetime. Since this is already a popular article, though, I’m not sure what the comments add. And surprising that there is no discussion of ab initio calculations, although this can be found in this technical introduction.
- There are serious prospects of launching a refueling station for geostationary satellites. A simple “tugboat” design is an alternative concept, which would push satellites directly rather than transfer fuel to them. (See also ConeXpress and the Robotic Refueling Mission.) Apparently, both approaches are viable for a surprisingly large fraction of geostationary satellites: 75% and 90%, respectively. It’s not clear to me how this is more efficient than those satellites bringing enough of their own fuel in the first place. I guess the idea is that the future value and lifetime of the satellite isn’t known at launch, so that it may be efficient to launch several satellites with modest fuel and only re-boost or re-fuel those that prove useful over an extended lifespan
- Earth and Moon seen between Saturn’s rings from Cassini.
- Despite the US’s dominance by teams (23 of 30), the “National” in the NHL refers to (mostly French) Canada; the league’s initial 4 teams in 1917 were the Montreal Canadiens, the Montreal Wanderers, the Ottawa Senators, and the Quebec Bulldogs. The first American team, the Boston Bruins, joined in 1924. With the growth of international players, Canadians just recently slipped below half of the player population, with Americans making up about a quarter.
- Browser plugin that identifies and summarizes the important parts of those Terms of Service agreements you never read.
- Switch from Sodium lights to LEDs visible from space. (Related.)
Otters love to juggle rocks.
More video. (H/t Howard Wiseman.)
- The now-$3.2B WFIRST space telescope was doubled in size when the NRO donated an unused mirror.
- Volunteer teams in US who help families from Mexico recover the remains of their relatives who die crossing the border.
We can locate things in the solar system really accurately:
A position of Huygens’ landing site on Titan was found with precision (within one km – one km on Titan measures 1.3′ latitude and longitude at the equator) using the Doppler data at a distance from Earth of about 1.2 billion kilometers.
Excellent discussion of what it’s like to volunteer for a suicide hotline, with some political commentary on communities and rootlessness.
When people lament the demise of communities or multi-generation family units in the United States, this is the kind of mutual support they’re thinking of. The extent to which America was once comprised of warm, child-raising villages in its real-life past is, of course, greatly exaggerated, and we certainly shouldn’t romanticize local communities per se: they always have the capacity to be meddling, oppressive, and exclusionary. But all communities don’t have to be like that, and instead of abdicating community ideals as outdated, we could be working to realize them better in the particular places we live. As American lifestyles become increasingly mobile and rootless, close involvement in a community may not be foremost on people’s minds; to the extent that people these days talk about “settling down” somewhere, they usually seem to be thinking in terms of sending their kids to a local school, patronizing nearby restaurants, and attending summer concerts in the park, not trundling around to people’s homes and asking what they can do for them.
But even if we aren’t planning to live in the same town for the entire rest of our lives, we mustn’t allow ourselves to use this as a convenient excuse to distance ourselves from local problems we may have the power to ameliorate. People who come to the U.S. from other parts of the world often find our way of living perverse, in ways we simply take for granted as facts of human nature, rather than peculiar societal failings. I was recently talking to a Haitian-born U.S. citizen who works long hours as a nurse’s aid, and then comes home each night to care for her mentally disabled teenage son. She told me that if it were possible, she would go back to Haiti in a heartbeat. She was desperately poor in Haiti, but there, she said, her neighbors would have helped her: they would have invited her over for dinner, they would have offered to look after the children. “Here,” she said, “nobody helps you.” That’s one of the worst condemnations of American civil society I’ve heard in a while.
- If the RSS feed from your favorite blog only includes an excerpt from each actual post, this can keep you from reading it on the go with apps like gReader. However, FreeFullRSS lets you convert any page to an RSS feed. See also the email-newsletter-to-RSS converter previously mention on this blog.
LaTeX in commentsInclude [latexpage] to render LaTeX in comments. (More.)
- Talk on Collaborative Pedagogical Documents (1)
- Dominic “Understand the difference between open access and copyleft; be able to explain it to others”... – Apr 22, 5:13 PM
- Legendre transform (10)
- Jess Riedel I learned something about the Russian alphabet today :) > Biologists have it a little... – Apr 05, 12:20 PM
- Anton Tykhyi > It is §14C in the 2nd English edition because §14B contains examples. My pardon... – Apr 05, 8:34 AM
- Jess Riedel Thanks for the comments, Anton Tykhyi! > ...the fact that the Legendre transform defined in... – Apr 04, 9:58 AM
- Anton Tykhyi *Legendre conjugates – Apr 03, 3:44 PM
- Anton Tykhyi I don't think you're being quite fair to Arnold. In particular, the fact that the... – Apr 03, 3:43 PM
- Erik Schnetter This is Tropical Mathematics! See e.g. Gabriel Peyré: "Fourier is to convolution what Legendre is... – Mar 28, 1:22 PM
- Links for February-March 2018 (2)
- PhysWell (13)
- Talk on Collaborative Pedagogical Documents (1)
foreXiv by C. Jess Riedel is licensed under a Creative Commons Attribution-ShareAlike 4.0 International License.