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- Use IANA time zone names, not abbreviations or fixed offsets, for local timesThe IANA Time Zone Database records the history of local time for representative locations worldwide. Identifiers like America/Sao_Paulo stay valid when offsets or daylight-saving rules change, whereas abbreviations such as CST are ambiguous.
- Por que a massa de pão cresce durante a fermentação (e o que é a "prova")A levedura consome açúcares da massa e libera gás carbônico e álcool; a rede de glúten formada na sova retém o gás e a massa cresce. A prova é o último descanso antes do forno; prova curta ou longa demais prejudica volume e miolo.
- Maillard reaction vs caramelization: two different kinds of browningThe Maillard reaction is between amino compounds and reducing sugars and browns meat, bread crust and coffee; caramelization is the thermal breakdown of sugars alone. Cooking heat speeds both up, but the Maillard reaction can also proceed slowly at lower temperatures; they have different ingredients and produce different flavors.
- When was Hokusai's Great Wave made? How museum records date the printHokusai's Under the Wave off Kanagawa (the Great Wave) belongs to the series Thirty-six Views of Mount Fuji. Museums holding impressions date it slightly differently: the Met gives ca. 1830-32, the Art Institute of Chicago 1830/33 and Yale ca. 1831.
- The Gregorian leap year rule: divisible by 4, except centuries not divisible by 400In the Gregorian calendar introduced in 1582, a year is a leap year if divisible by 4, except century years, which must be divisible by 400. So 2000 was a leap year but 1900 was not; the mean calendar year is 365.2425 days.
- Why historical sources give two different dates for the same event: Julian vs Gregorian calendarsCountries adopted the Gregorian calendar at different times, from 1582 to the 20th century, so sources may record one day under two dates. Isaac Newton, for example, was born on 25 December 1642 in the Julian calendar, which is 4 January 1643 in the Gregorian.
- Tratado de Tordesilhas (1494): a linha a 370 léguas a oeste de Cabo VerdeAssinado em 7 de junho de 1494 por Castela/Aragão e Portugal, o Tratado de Tordesilhas fixou um meridiano 370 léguas a oeste das ilhas de Cabo Verde para dividir as terras descobertas e por descobrir. A posição exata da linha nunca foi definida de forma consensual.
- Equação global da fotossíntese e de onde vem o oxigênio liberadoA fotossíntese oxigênica é resumida como 6 CO2 + 6 H2O + luz → C6H12O6 + 6 O2. O oxigênio liberado vem da água, como mostraram experimentos com isótopo 18O em 1941; a glicose na equação é uma convenção, pois o ciclo de Calvin produz primeiro açúcares de três carbonos.
- What evidence turned continental drift into plate tectonics?Alfred Wegener proposed continental drift in 1912 using matching coastlines, fossils and climate evidence, but lacked a mechanism. Post-war ocean-floor studies, including symmetric magnetic stripes and rock ages increasing away from mid-ocean ridges, supported seafloor spreading and led to plate tectonics.
- Terceira lei de Kepler: o quadrado do período orbital é proporcional ao cubo do semieixo maiorA terceira lei de Kepler afirma que o quadrado do período orbital de um planeta é proporcional ao cubo do semieixo maior da órbita. Kepler chegou a ela em 1618 e a publicou em Harmonices Mundi (1619); as duas primeiras leis estavam em Astronomia Nova.
- How the metre is defined: the speed of light since 1983, reworded in the 2019 SISince 1983 the metre has been defined through the speed of light in vacuum, which makes c exactly 299 792 458 m/s. The 2018 CGPM reworded the definition to fix c explicitly as a defining constant; the revised SI took effect on 20 May 2019.
- Problema de Monty Hall: por que trocar de porta dá 2/3 de chance de ganharNo problema de Monty Hall, sob as regras padrão (o apresentador sabe onde está o carro, sempre abre uma porta com bode e sempre oferece a troca), trocar de porta ganha com probabilidade 2/3 e manter ganha com 1/3. Se as regras do apresentador mudam, a resposta muda.
- Euclid's proof that there are infinitely many prime numbersEuclid (Elements, Book IX, Proposition 20) showed that no finite list of primes can be complete: multiply the listed primes, add 1, and any prime factor of the result is a prime missing from the list. The number itself need not be prime.
- Quais métodos HTTP são seguros e quais são idempotentes segundo a RFC 9110A RFC 9110 (2022) define GET, HEAD, OPTIONS e TRACE como métodos seguros, e PUT, DELETE e os métodos seguros como idempotentes. Idempotência se refere ao efeito pretendido no servidor, não a respostas idênticas nem à ausência total de efeitos colaterais.
- Building a job queue in PostgreSQL with SELECT ... FOR UPDATE SKIP LOCKEDSince PostgreSQL 9.5, the SKIP LOCKED option of the locking clause lets concurrent workers each claim different rows of a queue table without waiting on rows another worker has locked. The manual warns it gives an inconsistent view of data and suits queue-like tables, not general queries.
- Idempotency keys make retries safe under at-least-once deliveryWhen a client cannot tell whether a request succeeded, retrying risks performing the operation twice. A client-generated idempotency key lets the server recognize repeated attempts and return the original outcome instead of executing again.