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itcrowd

1,901 karma · joined January 16, 2016

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itcrowd··on What’s interesting about the Florida water system hack is that we heard about it
It has been widely reported that if you (two) would read the article, it mentions TeamViewer was used.
itcrowd··on The Covid-19 pandemic is getting worse
The comment:

> vaccine which is tested exclusively on young men

is COMPLETELY wrong.

1. The trials have been performed on both men and women

2. Age groups <65 AND >= 65

3. Also included chronically ill

From Moderna:

> As of today, the COVE study includes more than 7,000 Americans over the age of 65. It also includes more than 5,000 Americans who are under the age of 65 but have high-risk chronic diseases that put them at increased risk of severe COVID-19, such as diabetes, severe obesity and cardiac disease. These medically high-risk groups represent 42% of the total participants in the Phase 3 COVE study.

https://investors.modernatx.com/news-releases/news-release-d...

itcrowd··on Cooking for Founders
I am sorry to be so harsh, but this guide will not teach you anything about cooking, nor will it be of any particular relevance to founders [^].

The blog post is a 3,500 word advertisement to Amazon affiliation links. A selection of "helpful" advice given in the post:

- How to chop food? "Just search them on YouTube"

- "When you are first learning to cook I recommend avoiding complex recipes"

- "Get cooking"

Finally: "The goal of this post is [..] to provide fairly comprehensive [..] roadmap for going from a cooking noob to solid home chef." Sorry. This is not it.

[^] Alternatively, the title might be interpreted to mean "Cooking for founders [who are visiting you]". This is also not the case.

itcrowd··on Wikipedia frequently-encountered sources, color-coded by perceived reliability
I guess something to the extent of: "[action X] was widely mocked in the press ..."
itcrowd··on Ask HN: Who's looking for a co-founder?
Sorry to be of no help, but the platform looks really nice! Congrats & lots of success!
itcrowd··on Ask HN: Who's looking for a co-founder?
How do you have 10k teachers and 20 students? Or am I missing something (or a typo)?
itcrowd··on Chess tactics explained
I thoroughly enjoy Stjepan Tomic's channel "Hanging pawns" (on YouTube) for more detailed analyses than Agadmator. Videos are long but excellent and (i find it an advantage that) he doesn't go with the latest hypes around chess only (i.c. Queen's Gambit tv show)
itcrowd··on 1% of people cause half of global aviation emissions
I wasn't disagreeing with you, I was adding to your information.

It seems about 87%-53% = 34% of Americans fly once a year.

itcrowd··on 1% of people cause half of global aviation emissions
That is for Americal Airlines (the company) only. The number of American (adults) that never fly is about 53%.

See Fig. 7 in the research paper linked in this article: https://www.sciencedirect.com/science/article/pii/S095937802...

itcrowd··on 1% of people cause half of global aviation emissions
It is more clear from the research paper linked in the article. The distribution of emissions is about commercial passengers (71%), freight (17%), military (8%) and private airplanes (4%).

See Fig. 1: https://www.sciencedirect.com/science/article/pii/S095937802...

itcrowd··on 1% of people cause half of global aviation emissions
Source: TFA
itcrowd··on 1% of people cause half of global aviation emissions
The 1% figure sounds insane, but remember that "11% of the world’s population took a flight in 2018". In other words, about 10% of the flyers cause half of aviation emissions.
itcrowd··on Platypus: With Great Power Comes Great Leakage
Every once in a while, these vulnerabilities get their own website, such as in this case. Is there a meta website that collects all of these websites? I'm interested because I would like to analyze these websites and see if I can find some heuristic or threshold for what constitutes enough impact to support the creation of such a vanity website (one of the earliest examples that I remember is heartbleed). Maybe there is some insight for me personally or, if I can find something, for a wider audience.
itcrowd··on Finally, a Problem That Only Quantum Computers Will Ever Be Able to Solve (2018)
(2018) but very well written! Even with a limited grasp of complexity theory, it stuck for me.
itcrowd··on Dutch brewery burns iron as a clean, recyclable fuel
I have seen this story in several outlets, but haven't heard about NOx emissions from this process. Could someone more knowledgeable shine a light on this?
itcrowd··on Over 80% of Covid-19 patients in a hospital study have Vitamin D deficiency
From your link:

> One-third (33.9%) of the Spanish population may be at risk for Vitamin D deficiency.

So that doesn't explain the >80% from TFA.

itcrowd··on Over 80% of Covid-19 patients in a hospital study have Vitamin D deficiency
> The overall prevalence rate of vitamin D deficiency was 41.6%, with the highest rate seen in blacks (82.1%), followed by Hispanics (69.2%).

So doesn't explain the whole observed effect

Edit: also the study was in Spain, not USA

itcrowd··on Ask HN: Is Fortran worth learning in this day and age?
In addition to your sources, the book "Modern Fortran - Building efficient parallel applications" was just published this month. My hardcopy is on its way now, a PDF is also available for sale. I can't vouch for its content (yet) but it seems like a good starting point and also includes some advanced features.

https://www.manning.com/books/modern-fortran

itcrowd··on 4Chan Smear Campaigns Seek to ‘Red-Pill’ Boomers with Fake Snopes Content
> "mostly false" because he said "predators", not "superpredators"

Also because he wasn't referring to Black people but rather to young people. You have to read your own link better.

From Snopes: " What's True

While speaking in the Senate in 1993 in favor of the Violent Crime Control and Law Enforcement Act, Biden referred to young people who have become criminals as "predators."

What's False

Biden did not use the term "super-predator," nor did he specifically refer to Black people. It was Hillary Clinton who, while speaking about the Violent Crime Control and Law Enforcement Act a few years later, referred to young gang members as "super-predators." "

itcrowd··on Ask HN: Were you in the early 2000s HTPC scene?
OP's username checks out
itcrowd··on Oxford scientists develop extremely rapid diagnostic test for Covid-19
Could someone explain me this. The authors say (in the preprint [1]):

"The trained network was able to differentiate positive and negative IBV samples with high accuracy (91.4%), sensitivity (91.9%) and specificity (90.9%) (Fig.2G). Of note, these probabilities refer to single virus particles in the sample and not the whole sample; the probability of correctly identifying a sample with hundreds or thousands of IBV virus particles will therefore approach 100%. "

But then when the actual lab tests are performed:

"The trained network was able to distinguish between virus-positive and virus-negative samples with excellent accuracy, distinguishing between SARS-CoV-2-positive and negative BBXs with an accuracy of ~70% (Fig.3A)".

An accuracy of 70% is totally useless for such tests if widely applied, right? What am I missing here?

[1] https://www.medrxiv.org/content/10.1101/2020.10.13.20212035v...

itcrowd··on Uber Wasted $2.5B on Self-Driving Cars
Original source: https://www.theinformation.com/articles/infighting-busywork-...
itcrowd··on New Zealand is about to test long-range wireless power transmission
> They could be in a phased array

So could any other type of antenna, basically. It doesn't have to be a dipole, though.

> or in the center of a parabolic reflector

Based on the images, that's not what happens here

> There is no possible way to increase on efficiency in a passive antenna.

That is absolute horseshit. Large dipole arrays will suffer from high mutual coupling which could drastically reduce performance (depending on design choices). Different antenna types might be more suitable for different scenarios, but that's why I would like EmRod to explain their choices.

Furthermore, a rectenna gives you DC power out, but why would EmRod want this?

itcrowd··on New Zealand is about to test long-range wireless power transmission
The patent is easy to find, but not yet public because it is still pending approval. I am interested in the technical details disclosed in it.

https://patents.google.com/patent/AU2019904254A0

itcrowd··on New Zealand is about to test long-range wireless power transmission
By popular demand:

3 meter diameter panels @ 5 GHz gives a diffraction-limited beamwidth (FWHM) of lambda/D = (3e8/5e9)/3 * 180/pi = 1.5 degrees

0.75 degrees (1.5 degrees is the full angle) gives tan(0.75×pi/180)×(2×40) = 1 meter panels at receive (40 meter from transmit) to intercept the FWHM power. So a 3 meter receive panel will intercept more than the FWHM --> 70% seems like a realistic number for the percentage of power intercepted.

itcrowd··on New Zealand is about to test long-range wireless power transmission
I agree my math was wrong, I am sorry and I have removed it. I should not be commenting on the internet late at night.

I have crunched the numbers again on a new envelope, and with some realistic Tx/Rx panel size (3 meters) at 5 GHz, I see how you may end up with 70% efficiency assuming diffraction limited panels but also with 100% efficiency of the electronics.

Since I have the idea that you are part of Emrod, I would like to ask you why you opted for rectennas at receive and not some other antenna tech? Is it simply the integration between antenna and rectifier (smaller footprint?) or are there more reasons?

itcrowd··on New Zealand is about to test long-range wireless power transmission
Let's do the math. edit: math was wrong, I am very sorry
itcrowd··on The coronavirus is mutating – does it matter?
Nothing in your source about the mutations being slower to spread or more deadly. In fact, the mutations aren't named and D614A is not mentioned. None of your claims held up to even the slightest scrutiny. Your credibility has officially been lost and I will not reply to you any further.
itcrowd··on The coronavirus is mutating – does it matter?
Well, unless you can come up with a source (any source, even if it is in your native language), I can't judge your claims other than "made up". There's enough unsubstantiated (mis)information out there about sars-cov-2, we don't need you to post more without evidence.
itcrowd··on The coronavirus is mutating – does it matter?
Your information seems to come from a pre-print on MedrXiv [1], but not all your claims are supported. Especially the spreading rate and "deadliness" of the new mutation are not mentioned in the paper. The paper (which has not been peer reviewed) only notes the discovery of this new mutation. If you have other sources, I'm open for more information.

If you are wondering why D614A is not mentioned in the Nature article: the preprint has been out for 2 days (Nature published yesterday) and this information is only based on a single pre-print, not a peer-reviewed scientific article. I don't think saying "who cares about obscure -stans" is fair towards the author of this article.

[1] https://www.medrxiv.org/content/10.1101/2020.09.04.20184721v...

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