A circadian rhythm/sɜːrˈkeɪdiən/ is any biological process that displays an endogenous, entrainable oscillation of about 24 hours. These 24-hour rhythms are driven by a circadian clock, and they have been widely observed in plants, animals, fungi, and cyanobacteria.
The term circadian comes from the Latin circa, meaning “around” (or “approximately”), and diēm, meaning “day”. The formal study of biological temporal rhythms, such as daily, tidal, weekly, seasonal, and annual rhythms, is called chronobiology. Processes with 24-hour oscillations are more generally called diurnal rhythms; strictly speaking, they should not be called circadian rhythms unless their endogenous nature is confirmed.
Although circadian rhythms are endogenous (“built-in”, self-sustained), they are adjusted (entrained) to the local environment by external cues called zeitgebers (from German, “time giver”), which include light, temperature and redox cycles. The medical condition of the circadian rhythm in human is known as circadian rhythm disorder.
To be called circadian, a biological rhythm must meet these three general criteria:
- The rhythm has an endogenous free-running period that lasts approximately 24 hours. ..A rhythm cannot be said to be endogenous unless it has been tested and persists in conditions without external periodic input. ..
- The rhythms are entrainable. The rhythm can be reset by exposure to external stimuli (such as light and heat), a process called entrainment. ..
- The rhythms exhibit temperature compensation. In other words, they maintain circadian periodicity over a range of physiological temperatures. ..
adding this day
Doug Peterson (@dougpete) tweeted at 3:10 AM – 4 Oct 2017 :
3 scientists just won the Nobel Prize for discovering how body clocks are regulated — here’s why https://t.co/WAXZL1rC40 via @flipboard (http://twitter.com/dougpete/status/915504321378230272?s=17)
these researchers played a key role in identifying how cells in organisms regulate the internal body clock — also known as the chronotype or circadian rhythm — that determines when people feel awake or sleepy.
Chronobiologists, who study this kind of science, emphasize the importance of the discovery because it’s only after accepting body clocks as a biological fact that you can fully appreciate how big a role they play in our health. Our body clocks have huge effects on things like cancer risk, mental health, and obesity.
Some think the biological clock is an issue only for “sensitive people,” Roenneberg writes, which explains the common sentiment that it’s possible for people to change their natural rhythms to fit a schedule that a job or school may require. We know, however, that biological clocks can be changed only to a limited degree — and for some people, not much at all.
It’s when our lives aren’t matched with our body clocks that things start to go haywire. Night-shift work and exposure to bright light at night (which can start to shift the body clock) can cause a sort of internal jet lag. The same thing happens when you’re flying to a new place.
People whose schedule changes regularly, making it impossible to have consistency, can experience the biggest problems. They may more easily gain weight, are more likely to have a mental illness like anxiety or depression, and undergo biological changes significant enough that the International Agency for Research on Cancer has classified shift work as a “probable human carcinogen.”
That’s why, more than anything else, sleep researchers say that having a regular schedule is key.
time – algo vs chrono.. and the algo ness of chrono
nathanjurgenson (@nathanjurgenson) tweeted at 5:59 PM on Wed, Oct 04, 2017:
“What we need is a diversity of algorithms and the power to shape them” https://t.co/Y8oLz3C9NR
Linear time is an algorithm that has become so incontrovertible, so deeply foundational to our worldview, that it’s almost impossible to conceive of time any other way. ..social media feeds do show that there are other ways of organizing temporal events. We are right to refuse social media’s monopoly and ask who benefits when a timeline is adjusted. But are there other, new algorithms for time that we can develop ourselves?
Perhaps time can be considered as protean lines of flight, mutant futures up for constant renegotiation. Or uncommodified, irregular, and co-existing alter-rhythms. . t Or time reconfigured as slime mold — “queer critters,” to borrow from Karen Barad — defying both taxonomy and the limits of “human nature.” We need models of both human and environmental care; it’s crucial to think along with other kinds of planetary timescales, especially given the urgency of climate change.
future isn’t some fixed and irrefutable point on a timeline but an exercise in collective imagination..t
Michel Bauwens (@mbauwens) tweeted at 7:14 AM on Mon, Sep 30, 2019:
something very radical has happened to the financial system, please listen at least to the first five minutes
25 min video – Keiser Report: Time No Longer Has a Price (E1442)
1 min – stacy: negative interest rates are poison – kohler
2 min – max: interest rate model is dead.. can’t make any diff between diff time values of money.. so this is the end game of monetization and neolib.. we get to watch in our lifetime.. social fall out will be spectacular.. we already see uprisings all over the world getting ready for the global insurrection against banker occupation..
3 min – reading from keiser report: historically banks made money out of time.. if time no longer has a price, because there is no more interest.. t.. nothing can be earned – moneymaven.io.. stacy: so time no longer has value
earn a living ness
4 min – max: so we’re entering a new post time.. not even post capitalism.. it’s post time.. we’re living in the twilight zone of banking.. time doesn’t exist..t
‘in undisturbed ecosystems ..the average individual, species, or population, left to its own devices, behaves in ways that serve and stabilize the whole..’ –Dana Meadows
6 min – max: everything has been securitized and sold forward 20 yrs.. and everything has been consumed.. so now we’re in a dead planet – everything on planet earth is dead because it’s been securitized and we’ve consumed it all ..t
perfect opp/time to try something different.. new/old thinking on the global situation ie: a nother way for 8b people to live
stacy: time did have value.. but we cashed it all in for the next 40 years
the rest goes into neg rates and current money market and bitcoin et al specifics – not deep enough
real life mag‘s circadian media
via maria.. alan lightman’s einstein’s dreams: https://www.brainpickings.org/2021/08/28/alan-lightman-einsteins-dreams/
Long ago, before the Great Clock, time was measured by changes in heavenly bodies: the slow sweep of stars across the night sky, the arc of the sun and variation in light, the waxing and waning of the moon, tides, seasons. Time was measured also by heartbeats, the rhythms of drowsiness and sleep, the recurrence of hunger, the menstrual cycles of women, the duration of loneliness. Then, in a small town in Italy, the first mechanical clock was built. People were spellbound. Later they were horrified. Here was a human invention that quantified the passage of time, that laid ruler and compass to the span of desire, that measured out exactly the moments of a life. It was magical, it was unbearable, it was outside natural law. Yet the clock could not be ignored. It would have to be worshipped. The inventor was persuaded to build the Great Clock. Afterwards, he was killed and all other clocks were destroyed. Then the pilgrimages began.