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omar_a1

106 karma · joined June 4, 2019

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omar_a1··on GM’s CEO Offers to Make Ventilators in WWII-Style Mobilization
In your example, a 30% mortality rate is a very big deal. If we had a hypothetical cure that killed 30% of the people it was administered to, I doubt it would get very far.

I'm not saying the alternative is do nothing. But playing doctor because you think that you're reasonably qualified to administer a ventilator, then we're going to end up with, say 30% mortality rates from patients whose lungs were sucked through a ventilator tube because you guessed the wrong pressure. Or, more realistically, a terrible infection because you decided soap and water in the bathroom sink would be sufficient to clean the apparatus.

And then what do you suppose will happen after 30% of these amateur medical procedures go South? Are you going to throw in the towel, try something even more reckless, or decide that you need to get an actual doctor involved to clean up your mess? At which point, you've just added yet another case to the already overburdened medical system. And at a 30% failure rate, that would become a major burden.

There's a lot of room for action between doing nothing and acting foolishly (such as claiming a 30% mortality rate for botched medical procedures is a rational tradeoff). There are ways to help the situation here that don't involve magically becoming a nurse overnight.

omar_a1··on GM’s CEO Offers to Make Ventilators in WWII-Style Mobilization
I don't know how to operate a ventilator, and have zero medical training, but I'm getting frustrated by the comments claiming medicine is trivially easy.

Even using a syringe or blood draw on a patient is something one needs certification to do properly. That isn't bureaucratic nonsense. Having worked with syringes and sterile technique, there are so many ways you can give your patient an infection or otherwise cause them life-altering complications if you don't know what you're doing, even for the actually trivial techniques. Operating a ventilator incorrectly will result in death. Likely a grisly one, as incorrect pressure differentials and human lungs are not a good combination.

Now that doesn't mean we need to stick to these bureaucratic rules as they are for this situation, but the people on here advocating for trying complicated medical procedures while knowing fuck all about medicine (or even biology) really need to take a step back and take an inventory of what they don't know, and can realistically expect to accomplish with neither the technical knowledge nor manual dexterity of a trained clinician. A YouTube video and a technical manual aren't going to cut it, folks.

omar_a1··on One of Darwin's evolution theories finally proved by Cambridge researcher
The explorer mindset is how scientists discovered penicillin, x-rays, and vulcanized rubber. Science isn't as cut and dry as the scientific method suggests.

I'd say to the extent that this behavior contributes to the reproducibility crisis, it has more to do with not backing that exploration with rigorous experimentation.

But more to the point, I'd argue that the lack of funding and publish-or-perish atmosphere has more to do with it. Academics don't necessarily publish because the results are noteworthy, but because they have to, regardless of the robustness of their methodology.

omar_a1··on Ask HN: Any biomolecular/bio-lab hackers working on DIY RT-PCR tests?
A 60% false negative rate test is better than no information whatsoever.

No! It's decidedly not better! This isn't web-scraping where any little bit of information you extract is good, even with a low signal-to-noise ratio. These are human beings. Being wrong here has serious consequences, to the point that you need to weigh the usefulness of the test against the risk of harm of misdiagnosis. You can't just go around diagnosing people willy-nilly if you're not sure about the results!

A false negative means someone will go out with a false sense of security, potentially interacting with vulnerable community members thinking they'll be fine. They may develop further complications due to writing off their symptoms as the flu, and not seek out medical intervention if the situation goes South. A false positive means someone is going into quarantine for two weeks at a major economic and housing consequences (particularly if you want to help poor communities). False positives and false negatives mean more lives will be lost. The stakes are higher, and so too is the need for ethical rigor.

So if we narrow the scope to just testing for Covid-19, are you saying it still takes several years to get to the point of just administering and evaluating the test, right?

I'm not saying the test will take several years to develop, I'm saying it would take you, a self-described layperson, several years to gain the technical skill and know-how to know how to correctly research, design and validate the test.

Specifically, labs are carefully controlled environments. Just getting into the grunt work mechanics of the technique, at bare minimum you need to learn aseptic technique, pipetting, sterilization, reagent prep, handling hazardous chemicals, biohazardous waste disposal, and establishing appropriate environmental controls for your lab. Starting from nothing, those will take at least a year of full-time experience to develop for any semblance of competence. Otherwise you'll be a bull in a china shop; your results will be too tainted by bad technique and inadequate environmental controls to get anywhere.

So is this one of the few areas of human endeavor that is absolutely non-automatable, or can we break down what is/is not within the realm of automation, and possibly leverage the few staff we have relative to the current need?

It's perfectly automatable, but that doesn't mean it's trivial. For one, someone needs to... actually automate it. Someone else needs to implement, maintain and troubleshoot the robotic lab equipment doing the automation. Still require highly specialized skills to do so.

omar_a1··on Ask HN: Any biomolecular/bio-lab hackers working on DIY RT-PCR tests?
Uh, sorry to be that guy, but if you have no experience with lab techniques, microbiology, lab instrumentation, or analytical method validation, this isn't the sort of thing you can reasonably expect to accomplish without dedicating several years of your life to getting the necessary technical skills, to say nothing of the huge sums of money it would take to set up your own lab.

It's kind of like deciding you want to build your own 3 story house by hand. You can do it, but buying a bunch of lumber and tools is a far cry from having the necessary skill to actually build it. Science is hard.

There's also a major ethical issue about the medical implications of testing someone for a stigmatized disease if you're not clear on the validity of the test. False positives and false negatives have a major impact on your community. And hand-waving away the implications of reporting a false positive or negative with the statistical caveats of the results doesn't cut it.

Patients tend to take test results at face value, so the responsibility to of weighing the ethical ramifications of when it's strictly necessary and when it's irresponsible to administer an unreliable test for a given patient fall squarely on your shoulders. (Not that that excuses the current administration's policy of negatively biasing reporting by not testing anyone.)

omar_a1··on What's so hard about PDF text extraction?
For something like bank statements, I'd use the rigidly-defined formatting (both number formatting and field position) to inform how to interpret OCR misfires. My larger concern then would be missing a leading 1 (1500.00 v 500.00), but checking for dark pixels immediately preceding the number will flag those errors. And I suppose looking for dark pixels between numbers could help with missed decimals too.
omar_a1··on Follow-up to “The dystopian world of software engineering interviews”
After failing several of these "let's see how you think" technical interviews, I've come to the conclusion that the way I think is deeply and fundamentally flawed.
omar_a1··on Follow-up to “The dystopian world of software engineering interviews”
It doesn't have to be equivalent, but it can't be entirely one-sided either. Two technicals are a major commitment. Even if we assume the nominal 4 hours, there's still lots of preparation that goes into taking those tests. And that's 4+ hours to get to speak to a human being assuming you pass. Otherwise, it's the "We appreciate your time," autoreply.

That's asking for too much upfront before the candidate can even decide if the job is a good fit. Job descriptions alone don't tell you much. That's where the phone interview comes in. It's a two-way street.

omar_a1··on Follow-up to “The dystopian world of software engineering interviews”
Sorry, but what you've outlined above doesn't show that you value the candidates' time. You require two rounds of technical interviews before any human contact. It's asymmetrical. By automating the first two steps, you've made it so that you can waste as much of the applicants' time as you want without expending any further time or resources on your part.

Also, from experience, I've never come across a two hour takehome that actually takes two hours. Everyone always says not to spend more than two hours on it, but I can't exactly turn in an incomplete assignment.

I'm glad it is working for you, but it's not something to be proud of. Essentially what you've done is replace the standard 30 minute intro phone interview with a 2 hour SAT.

omar_a1··on Follow-up to “The dystopian world of software engineering interviews”
So much this. Every place I've interviewed at wants cookie-cutter candidates.

I didn't think of the solution you had in mind, because I've identified another problem that you didn't consider. And somehow that takes me out of the running. Good luck with that.

Not to mention the nebulous and vaguely discriminatory "cultural fit" problem. So, even if I manage to ace the technical, I still fail.

omar_a1··on Follow-up to “The dystopian world of software engineering interviews”
Also the closely related phenomenon of holding candidates unfamiliar with the codebase to the same standards as the interviewer, who wrote half of it.

Yea, if I had also been working on this particular code for the past two years I'd be able to breeze through these problems too.

omar_a1··on Follow-up to “The dystopian world of software engineering interviews”
The technical interviews I've had are decidedly not fizzbuzz level problems. They're "implement new features in an unfamiliar codebase in 10 minutes while we watch closely and tell you that every line of code you start to write is the wrong approach."-problems.
omar_a1··on Ask HN: How do you handle conflicts with your peers?
So, I have a related question: What do you do when the comments aren't being made in good faith?

In other words, incessant, aggressive, and unsolicited, with the reviewer not backing down even after you've implemented their changes? (e.g. Their previously implimented suggestion now are the wrong approach according to their next round of comments.)

I've tried simply going along with it, recognizing my own technical inexperience compared to theirs, but end up getting nothing done because of the capriciously-set goalposts.

This has been a recurring problem for me. Any tips?

omar_a1··on Coding Interview Problems with Detailed Solutions, Test Cases, Program Analysis
To your last point, it's actually quite hard to break into this field because of these kinds of interviews. That, and every SWE job posting having a Sr. Prefix.
omar_a1··on Ask HN: Tips on making a fake window that displays a live feed of the outside
For redundancy. Chances are all the lenses aren't covered in spiders. If you have two, you could select the non-giant spider view, or even write up a quick and dirty script for deciding which camera seems to have the minimum number of giant spiders at any given time, then select accordingly.

...I don't like spiders.

omar_a1··on Ask HN: Tips on making a fake window that displays a live feed of the outside
Edge case, but you may need to think of a way to filter out bugs on the lense, or it might occasionally look like Attack Of the Giant Spiders outside.

Maybe multiple lenses?

omar_a1··on Why introductory chemistry is boring: a long-term historical perspective
Thank you! So much of this discussion is formed by a personal dislike of the topic or bad classroom experiences. I, personally, find accounting to be dreadfully boring, but I don't feel that the pedagogy of the field as a whole needs to conform to my particular tastes.

Also, lots of suggestions of incredibly dangerous classroom experiments to jazz things up, coming from people who don't know the dangers of the reactions they're proposing.

This is a bad idea. If you don't do your due diligence, you end up setting school children on fire [0].

[0]http://chemjobber.blogspot.com/2019/06/civil-trial-of-nyc-te...

omar_a1··on Why introductory chemistry is boring: a long-term historical perspective
Inorganic gets very complicated very quickly. You end up dealing with Group Theory and 3D symmetry operations before you know it. And this is ignoring bio-inorganic chemistry, which is also very important.
omar_a1··on Why introductory chemistry is boring: a long-term historical perspective
So, the 'cooler' experiments are also more dangerous, and your example is illustrative of that. I'd be hesitant to hand students a flask of aqua regia (the only acid that can dissolve gold) and tell them to go nuts.

Ignoring the obvious safety issue of every student having an effervescent, volatile strong acid solution (which is tricky to handle safely even as an experienced chemist), there are a handful of incompatible chemical combinations with aqua regia that would require an immediate lab evacuation and call to the fire department. You'd need constraints and some serious vetting of the students' plans before you could let them touch the stuff.

I like the idea of open-ended experiments, but technique is so crucial to these things that even if they're right in theory, in practice they'd often get a negative result because of technical shortcomings of their technique. This is why you end up with cookbook experiments

omar_a1··on Why introductory chemistry is boring: a long-term historical perspective
Setting aside the semantics about what constitutes an 'experiment', constant failure due to minutiea you didn't consider in your technique is what actual science looks like. It is deeply frustrating, but it's the nature of the beast. And it's how you learn, and become a better scientist.

It's the difference between writing pseudocode that vaguely looks like it does what you want, and having an actual, executable program that works as intended. The devil's in the details.

omar_a1··on Federal study confirms racial bias of many facial-recognition systems
In the same way that handedness has no bearing on programming ability. If your firm were staffed entirely by left-handed folk, it should rightfully raise questions about how that happened.

You seem overly defensive about your hiring process, and unsatisfied with any answer that asserts men and women are equal. Ironic, no?

omar_a1··on Federal study confirms racial bias of many facial-recognition systems
Because programming ability isn't determined by melanin concentration in the skin, or by what pronouns you use, and hence shouldn't show selection bias in hiring, save for a biased selection process.
omar_a1··on In glyphosate review, WHO agency edited out “non-carcinogenic” findings (2017)
Yup, those are common rhetorical devices for presenting scientific fact. It's like dismissing Evolution as "just a theory."
omar_a1··on Federal study confirms racial bias of many facial-recognition systems
So, a quick note that my comments regarding racial representation are somewhat US-centric. I'd expect a company in Europe to be a much higher % white because your population is.

> We should be hiring on ability to do the job and nothing else.

This is exactly my point! Yet there is quite a lot of inadvertent, or even blatant, racism and sexism that happens during the hiring process and on the job.

omar_a1··on Federal study confirms racial bias of many facial-recognition systems
That's why I sprinkled the word "ideally" so liberally throughout that comment, as that was the premise of your question. To actually reflect the population, you'd have to somehow address centuries of institutionalized disenfranchisement, de facto segregation, educational barriers, racially-moticated policing and disproportionate conviction rates (highlighted by the OP). That's a lot to put on a hiring manager who isn't even sure that racism is an actual, tangible thing.

Realistically, the most that hiring managers (save for huge FAANG institutions) can do is thoroughly ensure that their team isn't inadvertently (or blatantly) racist/sexist in their hiring process and on the job, and to post the job in enough places that a diverse applicant pool will see the posting.

With that said, hand-waving away that there are few to no women or African Americans/Latinos/Native Americans/etc. on the team with an overzealous application of the Equality Paradox is a pretty dangerous mindset to get into. It's essentially passing the buck, and is eerily reminiscent of the claims made by 1950's Southern US Politicians that Blacks were the ones who were self-segregating because they wanted to, not the other way around.

What I'm saying is, the ideal 50/50 gender ratio/representative race may be unrealistic for a myriad of reasons, but if you're a 50-person start-up with 2 women, one of whom is HR, and no black people, I'd take a good, hard look at the company culture that's being fostered, and particularly whether turnover for women and People of Color at your company is worse than average.

omar_a1··on Federal study confirms racial bias of many facial-recognition systems
Not a number per se, but ideally the racial and gender ratios of the team would reflect the total population of the area (country? Metropolitan area?) in which the company resides, with the standard caveats that random sampling would give a range of different combinations. So that'd be, a multinomial distribution with the probabilities that each race is chosen set at the demographic percentage of the total population.

In other words, ideally the racial and gender distribution of a team would be as inconsequential and unbiased as blood type or handedness, in that the aggregate demographic ratios on your teams would at least match that of the residential population in your area, and ideally that of your broader geographic location.

I'm not doing a good job explaining this clearly, but the simple answer is: more than one. No one wants to be the token hire.

omar_a1··on Federal study confirms racial bias of many facial-recognition systems
I'm glad that you were able to deliver a product that helped with accessibility, but part of the considerable effort it took was just in trying to understand what someone else's perspective is. It's less efficient than simply having a member of the team with real lived experience that can answer common-sense questions that your team agonized over answering.

And not to say this happened in your case, but even with that considerable effort, it's still very easy to end up with blind spots in your product that a more diverse team would have caught.

It's the same as hiring for any other level of experience for more routine technical skills. If your team has no experience in this area, they'd need to expend a much greater degree of effort to answer questions that someone who is experienced would already have known the answer to.

omar_a1··on Federal study confirms racial bias of many facial-recognition systems
Are you asking why you can't listen to an employee that doesn't exist?

But more to your point, if these oh-so-competent ML practitioners were doing their jobs right, we wouldn't be having this discussion.

The whole reason diversity is championed in hiring is precisely because a single individual's perspective can only see so far. And if you have a monoculture team who has experienced very similar life circumstances, you end up with the kind of narrow perspective that leads to more racist soap dispensers.

omar_a1··on Federal study confirms racial bias of many facial-recognition systems
I agree. I just have low expectations as far as diversity in tech goes (so, one black person and/or one woman on the team would still be a milestone many of these companies have yet to reach), but you make a good point: hiring only one person of color or one woman would still be very problematic.
omar_a1··on Federal study confirms racial bias of many facial-recognition systems
It's the methods being used to select, populate, label, and validate the training set that are the problem.

Basically, your team is composed of white dudes who don't see the problem with a ML training set consisting largely of pictures of white dudes.

To prevent this they'd have needed to A) Employ a black person, and B) Listen to said employee's feedback, in order to recognize the problem.

Edit: Also worth pointing out, just using a representative population sampling would still show racial bias, essentially weighting accuracy with respect to population percent. You'd probably need to have equal samplings of pictures of people from all races/genders/disabilities if you wanted equal accuracy across the board. That also includes picture quality and range of picture quality. Doubling up images, or using corporate headshot white dudes and grainy selfie People of Color could still cause issues.

Same logic applies to labelling. That minimum wage contracting firm used to decide who's who in the photos may exhibit racial bias, by virtue of the fact that most people do. If their accuracy in labelling is racially biased then so too will the algorithms that it's based on.

In short: Racist garbage in, racist garbage out.

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