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    What is the evolutionary advantage of synchronized flashing?

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      In firefly mating rituals, the males cruise by, flying around and flashing their signals to let the ladies know that they are looking for love.

      Meanwhile, female fireflies wait in the leaves, observing the males’ flashes. Each waits for a specific pattern of blinking light sequences are unique to each species. When they spot a pattern that they like, they flash the same signal back at the male as an invitation to come on over.

      Scientists estimate that, of the roughly 2,000 species of fireflies around the world, only about 1 percent synchronize their flashes in large groups. However, flashing Photinus fireflies are very common, especially in North America. They evolved to flash in synchronizing patterns as a solution to specific behavioral, environmental or physiological conditions, said Moiseff.

      Synchronous species of fireflies are often found in high densities, making it hard for female fireflies to see and register a lone male firefly’s signal. This suggests that there is a problem in the female’s information processing, which group synchronized flashing seems to compensate for, according to the study.

      But once a female sees the mass synchronized signal and responds, how does she decide who in the group is to be her paramour?

      “In the field, under natural conditions, we find that a responding female Photinus carolinus attracted several males,” Moiseff told Life’s Little Mysteries. “These males then cluster around her and interact among each other, as well as with the female.”

      Researchers do not know whether the female’s initial response is directed at a single male within the synchronous group, or whether she is responding nonspecifically to the group as a whole. But because her response flash attracts many males, it appears that she isn’t communicating with any individual male, Moiseff said.

      “Ultimately, however, she selected a single male to mate with,” Moiseff added. “The effect of this is that female choice is occurring separately from initial species recognition and attraction.”

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        I’d be interested to know that too… although it may simply be that there is no evolutionary disadvantage to it and that’s why the behaviour has continued.

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          You get a much brighter flash? I assume a single firefly is flashing with some kind of purpose (it’s a mating display for at least one species), so a bigger flash should be better.

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            You get a bright collective flash, but how are you going to attract mates towards yourself? That’s what I find puzzling.

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              If they’re able to attract mates from a much larger radius, then more of them will come, so perhaps everybody is better off.

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                Yeah, this suggests that flashing as a mating signal is limited to bringing potential mates into proximity. After that, flashing must not be a strong attractor, or synchronization would be strongly penalized. I’m guessing the synchronization is driven more by safety in numbers from predators.

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              I actually prefer this explanation; http://web.mit.edu/Kerberos/www/dialogue.html, perhaps its helpful to others as well

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                Interesting read, with a few neat ideas (I liked the idea of local data caching).

                Why no ECC RAM though? The Xeon supports it so it would be almost silly not to use it. Oh, and a SAS LTO-4 tape drive won’t cost much more than a SCSI LTO-3 drive but it’ll hold twice as much and almost certainly be faster.

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                  Thanks for the tips. I didn’t know about ECC ram. Is memory corruption pretty common?

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                    Good question. Jeff Atwood discussed exactly this issue in 2015 and Dan Luu followed up with some further discussion. I don’t think it’s absolutely necessary, but if your CPU supports it, why not?

                    Personally, I use it in every system I have that supports it. Yes, it’s more expensive, but why bother using something like ZFS (which I do) if you have no guarantee that bits aren’t getting flipped before they even reach the disk?

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                      Jeff Atwood cites google as the case for not using ECC.

                      Emulating google is also emulating googles mistakes.

                      There is some research to suggest memory corruption occurs especially at 8+ GB scales. Perhaps these problems scale with size so at 64GB it is likelier.

                      ECC in a personal machine is a trivial cost. At google scale even trivial cost can matter, but in this case, unless this is a gaming toy use ECC. I mean why not?

                      Some HN discution on the topic


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                        From that discussion:

                        While I was at Google, someone asked one of the very early Googlers (I think it was Craig Silverstein, but it may’ve been Jeff Dean) what was the biggest mistake in their Google career, and they said “Not using ECC memory on early servers.”

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                      Another benefit of tape you should’ve mentioned is increased longevity and better recovery. Many cheap mediums have worse longevity than they advertise. DVD-R’s, for instance, can become unreadable in mere years. Enterprise focus on future proofing with lots of tape use means it’s unlikely to disappear like Zip or MO’s. Less uncertaintly than things like BluRay.

                      The only remaining comparison are to cheap RAID arrays. Idk where they are in price per GB right now.

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                        Great point, I’m drafting an update to the article and will include this.

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                    Well, while interesting, this requires users to install an application.

                    I find it somewhat more worrisome when information inserted into the dailer can be compromised through side channels such as sensors, which in the case of android requires no authorization to listen to and can not be turned of or feed invalid data. As such it seems trivial to capture pins and user ids that some organizations employ.


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                        It will be very interesting to see how the enterprise vs consumer drives compare next year.

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                          If I were AMD or any Intel competitor there is a opportunity competing not just on performance but on trust and ownership. I if I were them I would try to open up their equivalents like AMD Platform Security Processor and enjoy the more savvy crowd recommending their systems.

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                            Well, as much as I hate to say it: this was only a matter of time, seeing how this was addressed at one of the more recent CCC conventions and pretty much ignored by telecom providers.

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                              Indeed here are the ccc videos from the other thread


                              As I said this is not the only example of insecure networks that put too much trust in the other network actors; Telecom, payment processing at point of sale, travel bookings all do this. In the end putting the ordinary users at risk.

                              While sad for the victims, maybe this turns the tide on the banning encryption debates in parts of Europe.

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                              Here is the talk from Engel https://media.ccc.de/v/31c3_-_6249_-_en_-_saal_1_-_201412271715_-_ss7_locate_track_manipulate_-_tobias_engel it is really interesting.

                              “Private” networks that do not employ encryption and validation needs to stop.

                              Here is another example with the travel agencies networks https://media.ccc.de/v/33c3-7964-where_in_the_world_is_carmen_sandiego

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                                I find I tend to use !:x as in !:1 !:2 and so on instead of !$.

                                !:x takes the x parameter from the previous command, so from “mv /test /nexttest” !:1 is /test.

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                                  a) this looks really cool!

                                  b) python 2.7 or 3.x?

                                  c) “utilize the benefits of multi-threading with minimal concern about the implementation details.” http://i.imgur.com/2RRXCb7.gif?1

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                                    This wraps concurrent.futures which were introduced in python 3.2. Its less than 50 lines of code, and a good way to learn decorators, I recomend reading the source.