MakeUsersWant

I've heard it's lognormal, which doesn't follow the central limit theorem either.

Could you publish a set of known-good versions (pip freeze, OS version, etc)?

So this is why Europeans were able to colonize the entire world roughly in the 1700s.

I'd love property-based testing in big data cluster computing applications done in Databricks/Spark. However, (Py)Spark is very high-latency, even in local mode, so Hypothesis would have to generate a list (DataFrame) of thousands of test cases to be evaluated in parallel. That is where I got stuck. Has anybody ever done this successfully?

I wish there were something that opens the windows automatically at the right time to keep the heat* and humidity out. I'm sure other people will have had that idea, too. But I haven't come across easy-to-use hardware controls. That's not even talking about the full optimal control problem, i.e. weather forecast, the heat capacity and heat permeability of the walls, and any cigarette smoke coming in.

*Air conditioning is hard to get permission for as a renter in Germany.

Unfortunately not. There is a huge safety difference between a negative pressure test ("fit check" below) and a test with an actual aerosol ("qualitative fit test"). All of the FFP2 respirators I have checked pass one and fail the other. I am hoping the Narwallmask can fill this gap.

From https://associationofanaesthetists-publications.onlinelibrar...

Due to the associated time and costs, some health officials propose the elimination of fit testing and advocate that a fit check is sufficient in determining respirator fit [39]. The NIOSH conducted a study that demonstrated protection of N95/FFP2 masks improved from 67% without fit testing to 96% with fit testing [40]. Subsequently, NIOSH determined fit check alone to be insufficient and fit testing should be mandatory when selecting filtering facepiece respirators or elastomer half mask respirators.

Three studies that included 1111 Asians assessed the ability of fit check to detect leak determined by a quantitative fit test [36, 41, 42]. Average (range) sensitivity and specificity of the fit check to correctly detect leak were 26 (14–40)% and 79 (58–92)%, respectively, and consequent average (range) fit test pass rate following ‘successful’ fit check was 56 (34–73)%. Another study found the protection factor of filtering facepiece respirators increased from 3.3 to 20.5 when comparing the results of the entire test panel with those who had passed the fit test [32]. However, non‐fitted filtering facepiece respirators are still likely to provide greater protection than surgical masks, with a measured protection factor of 1.2 (Table 1) [32].

In summary, while fit check remains recommended before each use of any respirator to ensure fit on a day‐to‐day basis (Grade 1C evidence), we recommend not to use fit check as a substitute for fit testing to identify the size and shape of respirator that fits best (Grade 1B evidence).

For me, the Narwall's main value proposition beyond a standard FFP2 respirator is a super tight seal. Smoke is probably the best proxy I can test that with.

Would you be open to a full refund if I order it and can still smell cigarette smoke?

Thanks for your reply. I've elaborated some in the grandparent. I am willing to pay for quality once it is rigorously demonstrated.

The safety issue comes down to this paragraph in your FAQ:

What is the filter material and how is it tested? Our filters are made in the USA with material tested to >99.997% VFE (viral filtration efficiency) by Nelson Labs. Another metric is PFE (particle filtration efficiency). The N95 standard for 0.3-micron PFE is >95.00%, while Narwall's filter material is tested to >99.50% 0.1-micron PFE. You can learn more about these particle sizes here.

The way I read it, you test for 3um (VFE is that according to https://fixthemask.medium.com/the-standards-for-face-masks-i...) and 0.1um, but not 0.3um. I'd be happy if you could point me to papers that those two sizes cover 0.3um and saturation issues.

Is there some kind of independent verification of efficacy and safety of the whole device, not just the mask?

As a minor point - the sticker price is closer to $820 (4 persons times mask and 6 months of filters and international shipping).

I am legally required to wear a medical-grade mask (FFP2 or surgical). Do you have an official-looking document to show to the authorities?

I found you while researching how to verify a mask is good as an end-user, because I cannot get a good seal out of any of the six types of FFP2-masks I have tried. On the one hand, I've always been on the lookout for something similar. On the other hand, there are a few showstoppers that keep me from buying.

* Looks. Even if I can decide to look like the Reddit alien in a motorcycle helmet while everybody else is wearing an FFP2 mask, there is no way I can persuade my wife or kids. Would it be possible to make the exhaust pipe a bit more inconspicuous? E.g. inhale from the left cheek, exhale to the right cheek?

* Filtration efficiency and trust. There is a reason the FFP2/FFP3 standards test with 0.3um sized particles - those are the most difficult to filter out. Your marketing copy talks about 0.4um and 0.1um, and the headline screems about 3um large virus particles, which are even less relevant. Even though the 0.4um numbers look close to FFP3, any official certification is missing. Is it safe to say that your product does not meet the FFP2 standards?

Additionally, I'd love a mask that does not saturate out within minutes if I am panting (from chasing after kids).

https://fixthemask.medium.com/the-standards-for-face-masks-i...

* Sizing. How do I know which size I need? Maybe you could publish a guide like the CPAP mask manufacturers do. https://www.resmedshop.de/media/pdf/b1/e4/06/ResMed-AirFit-F... https://www.resmedshop.de/media/pdf/03/b0/57/ResMed-AirFit-F...

* Facial expressions. If you could make the mouth covering transparent, it would show my mimics in a conversation. That could be a killer feature, especially for socializing (or salesy jobs).

* Glasses and field of vision.

* Sticker price shock. Most FFP2/KN95 masks are counterfeit and none have a good seal, so I might as well grab the ones for $0.17 a piece from aliexpress. But, I am already spending much more on other Covid safety measures.

EDIT: Can you give me an accessible way to experience the mask's safety? So far, the best criterion I have come up with is if I can smell the smoke when I'm standing next to a smoker. In defense of that metric: There are absolutely no credible alternatives proposed on the internet. Mask fit used to be tested officially with noxious smoke. Cigarette smoke particles are pretty close in size to the virus-laden droplets. But in practise, an FFP2 mask passes this test only if I tape over all of its edges with a band-aid, and my skin won't tolerate that day-in day-out.

The ability to hire good junior engineers is one of the things that set a good senior engineer apart. So you might want to practise being an interviewer, even if you don't go into recruiting.

Could you please say more about how you find maths-intense software engineering niches and projects? What niches are there?

I too am a pure maths PhD with a background in software, but I am somewhat disappointed with the data science world.

How about you put the recovery code onto the invoice / credit card line?

Mix in special-needs children who need constant one-on-one support, young siblings, and dual career parents.

Covid stress falls completely off the radar.

Stitchdata.com, the maker of the ETL tools Stitch and Singer.io, is a different company (and is not being acquired).

Does pointing-and-calling focus the mind onto the task by the same mechanism as pair programming should focus it onto the bigger picture?

So far, I've always regarded pair programming as a fad for people who can only think in conversation. But maybe there is a plausible mechanism behind it.

Good relationships also take skills, such as: romance, understanding your spouse's point of view and what matters to them, maintaining the right equlibrum of intimacy and independence, being reliable, clearly expressing your own needs and making it emotionally safe for your partner to express theirs, conflict resolution, facing unpleasant truths, teamwork, respecting consent not just in sex, sexual communication, compromising on life plans, attachment style, staying mentally healthy, keeping the magic alive, etc.

You can probably test for those skills. I'm curious how.

Of course, you also need compatibility. But I have a hunch that's both overrated and easier to check for on a date.

Support redirected me their landing page - where the problem started. Still no prices.

Snowflake needs to debug their signup process.

I requested their pricing plan yesterday. Instead, I got two marketing emails "now that you have downloaded it" - but no pricing plan. The bug report got refused because "We noticed your email address is not associated as a Snowflake Support contact." Still no pricing plan, and no way forward.

What is your solution in practise?

Your techniques remind me of the book Maister/Green/Galford: the trusted advisor.

In Cologne, I have never seen light rail arrive on time, and I've used it daily for two years.

I'd love to pay $20 for a firefox extension that makes this problem go away. I use lots of privacy extensions on Firefox, and those Captchas are annoying as hell. Tor is even worse.

Can you please provide a few ready-to-use links?

Most projects don't actually want help. Go and try it: report a few bugs or point out usabilty issues. See what happens.

So that is why so many OSS projects are full of bugs and horrible usability. In the past, I have tried to help with clear, reproducible bug reports. Quite often I spent an hour tracking down a bug, writing up why it matters, and then got ignored or dismissed.

Those OSS projects that deliver a quality product, also took my bug reports seriously (and sometimes disagreed).

Lyx can produce both latex and ebooks from the same source document. You don't have to worry about latex technicalities while writing, and you can version it with git.

(I'm not affiliated with www.Lyx.org. But I wrote my PhD and masters with it.)

Can you please name a few example problems that could be solved with maths?

Whenever I found a way to apply research-level mathematics to a business problem, the solution always was too difficult to sell. Sometimes I can solve my own problem, e.g. options pricing models known from financial mathematics can tell you the minimum to accept in a salary negotiation.

I used to read Stiftung Warentest (the big consumer report in Germany). But they don't test for anything related to longevity, so I stopped. Frankly, I don't know where to look.

Will the $5000 fridge last 20 years? How do I know the manufactor isn't lying?

I would pay for a credible source of information how long various household appliances last. (I buy by TOC, and I also value my time.)

The problem is credibility. Manufacturers have an incentive to astroturf "independent" reviews. Insurerers have an incentive to rule out every common fault. And I want the data collection audited.

At this point, I'm ripe for appliances-as-a-service unless a big consumer watchdog steps up. Maybe there is room for a built-to-last manufacturer who goes to great lengths to show me they mean it. Maybe commercial appliances marketed to consumers?

For example, an essential user action requires 3 cryptically named menu items, deeply hidden in 5 layers of menus, each of with takes ages to open.

Does that count as a bug? Users will simply fail at their job. But for many (open-source) developers, only a segfault counts.

I have stopped reporting such things.