HN user
Why? It's an excellent recruiting tool. I used to read it as a kid (along with every other paper or digital encyclopedia I could get my hands on), and it certainly made me interested in the CIA.
This is very cool, thanks for sharing. There are many industries and academic fields where Matlab has gone out of fashion (I work in one), and my experience has been that there's a lot of over the top negativity about Mathworks products, centering mostly on the license and business model. But I think there's a lack of awareness of just how superior Matlab and Simulink are to all alternatives in some domains. All that to say: don't let the Matlab hate get to you, you're using the right tool for the job.
This is a fun dataset. The paper leaves a slight misimpression about channel statistics: IIUC, they do not correct for sampling propensity to reweight when looking at subscriber counts (it should be weighted ~1/# of videos per channel since the probability of a given channel appearing is proportional to the number of public videos that channel has, as long as the sample is a small fraction of the population).
It also includes the Apple One bundle. I wonder if the bundles complicate that breakdown — I certainly never use Apple Music or Arcade, and almost never TV+.
Anecdotally, I cannot figure out how to cancel One without losing my iCloud photo library. As soon as I do figure that out, I'll be iCloud only.
I don't think they were pretending to look, they were just (rightly) remaining open to it being either rescue or recovery. From the article:
“While not definitive, this information was immediately shared with the Incident Commander to assist with the ongoing search and rescue mission.”
So:
* They knew about it and quickly aided in the search.
* They did not broadcast the details of the collection to the public.
That seems like the right call to me.
and so must be hiding that they can do so
I don't believe I said that. You can draw your own conclusion from the fact that it is within their capabilities to detect, localize, and to some extent classify a wide range of sources in this region of the ocean.
What you won't find is a lot of information about those capabilities in the public domain. Just consider that what _is_ known tells us that we had these capabilities in the 1950s, and that they were continuously improved upon throughout the cold war. This is not Area 51 conspiracy speculation; it is bread-and-butter NRL stuff that is more than half a century old at this point and is classified for good reasons.
Hydrophones don't need to be nearby or even at a similar depth. The SOFAR channel acts as a waveguide and will duct sources from other depths as long as the bottom is below the critical depth. As others have said, this part of the North Atlantic is one of the most heavily monitored parts of the ocean as well. No sci-fi physics necessary — this has been done continuously since the 1950s.
We've gone from: - Uncertainty exceeding signal in satellite data is "simply not the case" ...
Not sure I can help someone who willfully misreads my comments! Give chapter 9 of the AR6 a read and then we can talk.
The thread is at max depth, so I'll reply here:
As you quoted from the paper:
The six main groups that provide satellite-altimetry-based GMSL estimates ...
1) You're restricting your attention to groups producing satellite-derived estimates.
2) Several of those groups, e.g. CSIRO, are using data assimilation to combine satellite estimates with gauges [1].
3) There are multiple satellites, often overlapping in time, often of totally different design/orbit/etc... [2]
4) Up to the most recent IPCC report (AR6), assessments were based on tide gauges alone [3]. For many of the reasons that you bring up. Hence "Nobody relies on estimates from a single satellite alone." Reconstruction of historical sea level is a huge scientific discipline and you would benefit from doing some more reading before beating a dead horse. The estimated uncertainty is large for a reason, but it does not encapsulate any scenarios where the observed change has been insignificant. If you think otherwise, I'd be happy to take your money for 2100 options on coastal real estate in about 90% of the world's coastline.
[1] — https://research.csiro.au/slrwavescoast/sea-level/measuremen... and https://link.springer.com/article/10.1007/s10712-011-9119-1
[2] — https://research.csiro.au/slrwavescoast/sea-level/measuremen...
[3] — https://www.ipcc.ch/report/ar6/wg1/downloads/report/IPCC_AR6... p.1287
Figure 1 from that paper didn't convince you that it was a minor issue? Their correction is about 7% of the 1993-2018 signal, and it resolves the discrepancy with respect to other estimates, including non-satellite ones. Nobody relies on estimates from a single satellite alone.
https://essd.copernicus.org/articles/11/1189/2019/essd-11-11...
Also that assumes the scientists are completely accurate and don't make any mistakes. As recently as 5 years ago they discovered that the measured rise for almost all of the 90s was wrong and revised it by 3mm/year +- 1.7mm/year - the error was the same amount as the imputed level of rise!
Citation for this? There are always improvements to our understanding of past data, but you seem to be implying that the uncertainty exceeds the signal. That's simply not the case [1].
[1] — https://www.ipcc.ch/report/ar6/wg1/downloads/report/IPCC_AR6... pp.1291-1292
Archimedes would like a word. There are some small effects due mostly to salinity differences, but sea ice isn't a major contributor because it is already floating and thus displacing an equivalent volume of water:
This article only briefly touches on what I think is the most interesting aspect of sea level rise: gravitational adjustment. Even though I never worked seriously on sea level research, it was by far my favorite course in graduate school. For anyone who would like to learn more, I highly recommend listening to Jerry Mitrovica expound on the subject [1]. I guarantee that you will learn a few things that will stick with you.
In my experience, the first order adjustment effects are not widely known even among physical oceanographers. I remember describing it to a preeminent expert on El Nino, and him being incredulous that local sea level fall near the source of meltwater could be the first-order effect beyond accounting for rebound. "The first-order response is a Kelvin wave — you've surely been misinformed."
[1] - One example lecture: https://www.youtube.com/watch?v=s_rGksRoG9A
[2] - Another, shorter summary talk https://www.youtube.com/watch?v=yj7JIxU9Af4
I've been very impressed with sqlglot, and am looking forward to trying this feature. The only issue I've had with sqlglot is transpiling for use with a specific spark version: in my experience Spark is not great about surfacing obvious 'not registered' errors when a function isn't supported (especially in >=2.4). I ran into this with width_bucket, which is only in the most recent release. I am curious whether there's a straightforward way to write with a specific release and catch the error in transpilation rather than execution.
Side note: Iaroslav (post author) and Toby (sqlglot creator) are both amazing, and I'm so glad that they're working on open source projects like this.
A cautionary tale from personal experience: My parents retired to a rural area and wanted to ensure that their area would remain a healthy old growth forest. They have been actively involved in a land trust that has successfully created large, continuous corridors throughout the area. One of their contributions was a continuous strip of about 20 acres. Their community has stitched these together to create wonderful cycling/walking paths through the woods, linking up different areas.
At the start of the pandemic, a developer bought up a large (~200 acre) tract neighboring them and the corridor. They immediately clearcut the whole thing, and are building hundreds of tract houses, cheek by jowl, and have consequently forced the local government to build additional roads. Guess the big selling point they use in their website and listings? 'Neighbors a wilderness trust with extensive woodland paths.'
Knowing all of this, I'm not sure whether I'd still go through with the land trust purchases or not. They couldn't have afforded the 200 acre parcel, and who knows if the developer would have bought the other 50 acres. All I can say is that it is dispiriting to see people doing the right thing and having a net increase in clearcutting at their doorstep.
I take it that you're looking only at the "All Infection" efficacy? While the original vaccines are clearly less effective at totally preventing infection with the latest variants, their efficacy against symptomatic infection and hospitalization is nothing to sneeze at — ~50% and ~90% respectively with a booster, eyeballing the table.
I love ThermoKlein... but then they'd have needed to engineer it to IPX8 standards to avoid excessive warranty servicing from cranky oceanographers.
Nitpick: gravity waves [1] pretty universally refer to waves in fluid media in which the restoring force is buoyancy. Ripples in spacetime are usually called _gravitational_ waves.
I'll refrain from picking a side, but Air Power Australia and the credibility of its proprietor Carlo Kopp are... controversial [1,2]. He has extensive knowledge of many of the relevant topics, but is viewed as having an axe to grind about particular systems as they pertain to Australian procurement decisions. Russian SAMs have always been shrouded in a huge amount of marketing mystery. While they are obviously capable and advanced systems, evidence continues to accumulate that some of the magic is smoke and mirrors.
I read this article with great interest over technical details, but stop short of accepting conclusions along the lines of "Flap Lid is comparable to SPY-1". Only the folks who train and operate against those systems in the real world really know if that's true, and it's one of the things we are least likely to have accurate information about in the public domain.
[1] https://www.reddit.com/r/CredibleDefense/comments/1vj7r6/is_...
Yay! For years I've been wanting some form of home-oriented fleet management tool for all of my stuff. I'm glad you've addressed maintenance reminders — I am so bad at keeping track of things like bike chain replacement and cabin air filter changes. Looking forward to trying this out.
There is an interesting relationship between frequency domain filtering and the distributional properties of a signal, which I believe the author encounters:
So interestingly, the IDFT method makes noise that is gaussian distributed. This kind of makes sense because we are filling out frequencies as uniform random white noise, which are turning into uniform random white noise sinusoids that are being summed together, which will tend towards a gaussian distribution as you sum up more of them. In contrast, the void and cluster method makes uniform distributed values which are perfectly uniform.
[0] https://s3-us-west-2.amazonaws.com/arpdfs/Publications/Prois...
These lectures look fantastic — thank you for making and sharing them! I've been looking for a good foundational treatment of optimization to digest over the holidays.
That's an odd generalization to apply when we're talking about an individual whose significant academic record is easy to find [0,1]. Many department heads are more senior, taking on organizational responsibilities that would be more of a burden to younger faculty. Perhaps that is what you're referring to. But in the scheme of things EAPS is - and always has been - high on the rigor scale and low on the bureaucracy scale.
[0] https://scholar.google.com/citations?user=RxOuRnMAAAAJ&hl=en [1] - https://hilst.mit.edu/publications/
However! I believe that the main benefit of central nuclear plants, is there ability to keep poisonous materials in a single location, so that it doesn't get lost.
Off topic, but: I often feel that problems related to hard-to-manage waste could be ameliorated by thinking of temporary solutions as "entropy-reducing storage". Especially with recycling — which is currently not cost effective [0] but perhaps could be in the future — we ought to keep the nicely sorted waste separated, and avoid mixing it in with other landfill trash. At a minimum, there's no point in actively increasing the entropy of trash and byproducts. That way, today's landfills could become tomorrow's mines with a lower bar for economic viability.
[0] https://www.npr.org/2020/09/11/897692090/how-big-oil-misled-...
I agree about the importance of actually living there and contributing (_not_ monetarily) to the community. Several of my roommates in college grew up in Bolinas, and for them it was clearly a magical and a formative experience. But this is only achievable if you have a critical mass of intentional community builders residing there. Despite some downsides (only one of my friends has been able to continue living there in the long term) and trickling gentrification, Bolinas seems to have successfully clung on to that ethos for now.
Agreed, my experience is CA-specific (though it also appears to be true in some other metros like Boston). The thing I was surprised about is that it's pretty normal for specifics in leases to not be legally enforceable, if not outright illegal.
Normally I'd have had a cordial discussion with my landlord, but in this case the landlord was a giant corporate REIT whose boilerplate lease was largely unenforceable (no doubt they know this, and have figured out that people assume leases are legally binding regardless of the terms).
FWIW, landlords often include unenforceable terms with respect to lease break fees [1]. This is a common pattern [2].
In my only experience with breaking a lease, my lawyer advised me to inform my landlord that I was aware of California state law, and then wait for them to negotiate. They initially counter-offered that I pay 2.5 months to break the lease, and ultimately agreed to 1 month. Probably harder to do during COVID, though, with such high vacancy rates.
[1] https://caretaker.com/learn/breaking-a-lease-early/mitigatin...
If anyone from Starlink is reading this thread: Add a Lat/Lon option for addresses in the service address entry form.
Many rural homes have mailing addresses that don't resolve correctly. For example, the input form forced me to use "Anacortes, WA" for my house in the San Juans. The islands are a perfect Starlink test market, whereas Anacortes has plenty of broadband options.
Sonofusion [0] was a neat idea, and some of the relevant experiments (at least the cavitation part) can be done on a bench top with a hobbyist level budget. Last I checked, the research had been somewhat tarnished by academic fraud. The physics of jet formation during bubble collapse near a solid boundary remains fascinating [1].
[0] https://en.wikipedia.org/wiki/Bubble_fusion
[1] https://authors.library.caltech.edu/48933/1/On%20the%20Mecha...
If you're implying that most of climate science is statistical modeling, please be specific and say so. While there is plenty of statistics in the field[1], the majority is basic physical science and dynamical modeling. Equivocation between statistical and dynamical models is surprisingly common on HN and leads me to suspect that a person hasn't taken much time to learn about climate science.
[1] Calling it a single field isn't really fair. It's the nexus of many specialized fields, most of which are purely physical sciences.