configuration – Any chance to revert/undo my last drush cim in Drupal 8?

No, you can’t revert drush cim without a backup (or alternate config export) of some sort. If you don’t have a backup, you’re out of luck.

One safety measure to prevent this kind of problem is to write a script that backs up your database and then calls drush cim. Then, only run the script to do a config import, and you can ensure you have always made a backup first.

blockchain – Do I have a chance to commit a transaction without any network fee?

I know how transaction fees are calculated. Also I understand that a transaction with a higher fee will be approved much faster than a transaction with the lowest one.

Does the bitcoin protocol allow committing a transaction without paying a fee (even if the transaction will be approved within 2 or 3 weeks)?

optics – Calculating f/stop chance for teleconverter that increases lens size

With a rear-mount converter, it’s always the factor of 2 (unless there’s a gross mismatch between lens and converter), but with your front-mount one, it’s not that simple.

The relevant question is where the light path is effectively limited.

Or, to put it another way: Does all the light collected in your converter’s front lens reach the sensor, or is some part of it blocked by the front opening of your base lens? If part is blocked, then the large converter front lens doesn’t help and is just a waste of material.

As a quick check, you can detach the combo from the camera body and look into it from the rear side, a few centimeters behind the lens, roughly where you’d expect the sensor. Do that with aperture full open. If you can fully see the circular edge of the converter’s front lens, then the 40mm-based calculation is indeed valid (all the light collected on that 40mm circle reaches the sensor). If you don’t, that means that the 30mm opening of the base lens still is the limiting factor, and the 30mm calculation will probably give better results.

And, if you want to do some experiments, compare the exposure times for full-open shots with and without the converter (of course, in a constant-lighting situation). If there’s a factor of 4 between the two times, the classical calculation applies, if it’s a factor of about 2, your 40mm-based calculation is correct.

Having said all that, I bet that you won’t be able to see the converter front lens edge, and that the exposure-time experiment will result in a factor of 4.

What is the Probability of Head in coin flip when coin is flipped two times if coin is biased ($60%$ chance of heads per flip)?

If unbiased coin then the probability of Head in coin flip when coin is flipped two times $= 75%$.
$$P(H_1 cup H_2) = frac12 + frac12 − frac12 times frac12 = frac34$$

But what is the probability of Head in coin flip when coin is flipped two times if the coin is biased and has a $60%$ chance of heads rather than $50%$?

boolean algebra – Minimization of an expression through K-map, in which there are more chances of errors and with Quine-McCluskey Method there are less chance of errors

Minimization of any expression of 4 variables through K-map, in which there are more chances of errors (like error in grouping) and the same expression with Quine-McCluskey Method there are less chance of errors but it should be of 4 variables. And I know that Quine-McCluskey Method gives accurate result as compare to K-map, when the number of variables exceed from 4 but what about 4 variables?

dnd 5e – How do I Show my PCs that an Enemy Gets a Random Chance at a Reaction?

My PCs are going to be coming up against a homebrew enemy.

Said enemy is tough, but slow, and very deadly up close. OK, they’re the Borg, lets say.

I have figured out how to telegraph all of the traits these enemies have. Yes, I am sacrificing NPCs early on in the encounter.

But, tough, slow, and deadly as these enemies are, I am giving a 33% chance at taking a reaction each turn. I want my PCs to consider that before trying to retreat. How do I make this clear without outright telegraphing it?

Giveaways – Get a Chance to Win $5 Daily | Proxies-free

Hi BMFers,

We started live streaming on our Youtube channel and offer the chance to win $5 or 5000 BMF points to one lucky active viewer daily.

The idea behind this giveaway is to make the livestream more active. Hope this will work. Thank you for your support!

Our live is 1 hour and we choose the winner with

Yesterday winner:
View attachment 171540

Our Youtube live link:

bitcoin core – I can not find a clear mathematical proof method with details and example for “near to zero chance of generating the same pair key wallet”

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