2) The International Space Station has used a dual-loop ammonia/water-based heat pump to cool the station temperatures. It's been in place for several decades. Heat pumps are a proven technology.

Other satellites have also used heat pumps, such as SES-17 in geostationary orbit https://www.esa.int/Applications/Connectivity_and_Secure_Com...

WireGuard takes 30 mins to an hour to set up, you'll need to configure port forwarding, DDNS, create keys for each device, and add them to each device manually. But you have 100% control.

Performance-wise, I haven't noticed a difference. My internet connection maxes out way before Tailscale hits any performance limits.

Tailscale wins for convenience.

It's about cost comparison: SF Muni's operating costs (in terms of costs per passenger mile) are so bloated they're comparable to chartering a helicopter.

This should not be possible, and it's a strong signal of poor fiscal management. SF Muni operates at $3.62 per passenger mile. For comparison, Transport for London (TfL) operates at around $0.50/passenger mile and Shanghai Metro operates at $0.11/passenger mile.

The Federal government spends ~$17.5B/year on maintaining and constructing the interstate highway system. Americans drive 852 billion miles/year on it. The cost per Vehicle Mile Traveled (VMT) is 2.1 cents / mile.

If we look at all government spending (Federal, State, Local) on highways, roads, and supporting infrastructure (which includes traffic management systems), that's around $285B/year and 3.28 trillion miles, or 8.7 cents per Vehicle Mile Traveled.

The cost to the government to provide and maintain roads is on the order of several cents per mile traveled per year. Roads are simply much more cost-effective to build and maintain than dedicated public transit infrastructure.

If public transit is less cost-effective than taking a helicopter, then something is clearly broken.

In the bay, low-skilled / manual laborers spend >50% of their income on housing. Many can't afford to live here, so they demand higher wages or leave, which drives up the price of labor even further.

If sufficient housing were built and the Bay Area had the same housing prices as the rest of the US, then 1) the supply of labor would go up 2) wages could fall by 30-40% without a quality of life decrease. Businesses could reduce their labor costs by 20%, which would improve the QoL of everyone in the area, including manual laborers. When local businesses cut costs, then everything costs less (food, housing, transport), and QoL goes up.

Then run this process iteratively and you will see massive reductions in prices everywhere, the cost of everything will go down by 30%+ percent.

For the case of BART, they spend ~$800 million / year on labor, so reducing cost here has the highest RoI. They would save hundreds of millions per year.

JR East in Japan operates in the same way: it makes the majority of its profit from the real estate, malls, and hotels it operates adjacent to its train stations.

I remember talking to a VC a few years back, and he vehemently explained why he will never ever fund companies related to public transit, for this reason. Public transit was one of the two sectors he would not invest in (the other being materials science).

For BART, that number is:

$1.07B operating expense / 892.5M million passenger miles traveled = $1.20 per mile. Then subtract out the fare per mile and the government is paying $0.84/mile for people to ride BART.

But you cannot run a transit system on marginal costs, so using that comparison is also misleading.

  Cost per passenger trip:
    BART: $1.07B operating expenses / 59.5M trips = $16.92
    SF Muni: $1.13B / 160M trips = $7.06
    Caltrain: $225M / 9.1M trips = $24.73

  Passenger Fare collected per trip:
    BART: $259M / 59.5M trips = $4.35
    SF Muni: $111M / 160M trips = $0.69
    Caltrain: $58.7M / 9.1M trips = $6.45

  Subsidy per trip:
    BART: $12.57
    SF Muni: $6.37
    Caltrain: $18.27

  Cost per passenger mile:
    BART: $1.07B / 892.5M passenger miles = $1.20/mile
    SF Muni: $1.13B / 312M = $3.62/mile
    Caltrain: $225M / 177.5M = $1.27/mile

  Subsidy per passenger mile:
    BART: $1.07B / 892.5M passenger miles = $0.84/mile
    SF Muni: $1.13B / 312M = $3.26/mile
    Caltrain: $225M / 177.5M = $0.94/mile

For comparison, federal spending for the interstate highway system is about 2-3 cents per passenger mile.

Comments URL: https://news.ycombinator.com/item?id=49810113

Points: 25

# Comments: 14

PDFs are meant to be a presentation document format, not an editable document format. I have some experience editing PDFs, and it's difficult to make significant modifications. Editing small sections of text or replacing a date is fine, but once you try to start editing entire paragraphs or changing the layout, it quickly becomes unmanageable. The kerning looks weird, the spacing between words looks off, and when you look into it you realize the the sentence you're trying to edit is actually split across a dozen text objects. For these it becomes almost impossible to edit without destroying the spacing, so you just give up.

And the approved way to edit these PDFs is via Adobe Acrobat Pro, which costs $20/month (ugh), which I'm not willing to pay for.

So I think this is why we just don't see that many PDF forgeries. The editing tools just aren't very good. Maybe it's different now we can just ask Claude to edit our PDFs for us.

Apple is already rumored to be working on their own smart ring. Samsung is already in the market. This is one reason why Oura is in a rush to IPO, they need liquidity for early investors + cash to compete before Apple comes in and takes a huge slice of their market.

That's entirely why they can blow compute on the fun projects like this. If they had to pay extra for the electricity, they wouldn't do it.

Though, it would make more financial sense to mine crypto.

Those M2 Max Geekbench benchmarks appeared on November 30, 2022. Apple announced the Apple M2 Max chip on January 17, 2023.

Similarly, those M4 Geekbench benchmarks for Mac were leaked on October 6, 2024, prior to Apple announcing the product. Apple announced the M4 Macs on October 28, 2024.