Currently viewing a development environment

Drop Buffon’s Needle on the floor a thousand times and estimate pi

It’s Pi Day. Don’t prick your finger, it’s mathemagic!

Coleman Harris

Biostatistics

Vanderbilt University

Philosophers and researchers have long searched for estimates of pi, from approximations using the golden ratio to the famous fraction 22/7. One such estimate was accidentally discovered by French mathematician Georges-Louis Leclerc, Comte de Buffon – Buffon for short. He asked a simple question: Suppose a needle of a particular length is dropped onto a wooden floor with evenly spaced boards of the same width. What is the chance that the needle crosses a crack between the boards? 

wood boards

A needle in a pi-stack

Tim Mossholder

The angle of the needle determines how likely it is to have crossed the crack: with a smaller angle between the needle and the cracks, it is easier for the needle to land without crossing one. So, the solution to the “Needle Problem” relates the sine function to the needle’s angle, drawing a curve where the needle will always cross the crack. The area under this curve is compared to the rest of the area the needle could have landed, estimating the chance the needle crossed a crack. The resulting ratio relates the length of the needle, the distance between the needle and the crack, and pi – a simple shuffling of variables yields an estimate of pi.

Now, if you were to drop a needle on a wooden floor yourself, it would take you thousands of attempts before you could reasonably calculate pi. That’s because the ratio mentioned above is in the case of infinite attempts – in the real world, we are limited to the number of times we can drop a needle. Researchers at the University of Illinois – Urbana-Champaign developed a simulation to virtually drop needles and estimate pi. On this Pi Day, try it out to see how close you can get to pi using Buffon’s Needle.

A newly discovered cryosphere-dwelling yeast stays alive by making ethanol

Rhodotorula frigidialcoholis was isolated from 150,000-year-old permafrost in the McMurdo Dry Valleys of Antarctica

Mitra Kashani

Microbial Ecology

Centers for Disease Control and Prevention

El sur de Inglaterra alberga a una pequeña, pero prospera población de walabíes de cuello rojo

Los walabíes fueron introducidos al país al principio del siglo XX

Maria Gatta

Ecology and Conservation Biology

University of the Witwatersrand, Johannesburg

Walabíes: son muy monos, relativamente pequeños, y para los europeos, tienen una apariencia inédita. Esto es lo que llevó a la introducción del walabí de cuello rojo, una especie australiana, a principios del siglo XX a países como Inglaterra, Irlanda, y Francia. En aquellos tiempos, los walabíes se mantenían en zoos y colecciones privadas. Algunos escaparon, sobre todo durante la segunda guerra mundial, cuando la gente tenía cosas más importantes por las que preocuparse por mantener vallas.

Hoy en día, hay muy poca información disponible sobre que les pasó a aquellos walabíes introducidos. Dos científicos, Holly English y Anthony Caravaggi, decidieron investigar qué pasó con aquellos animales. Recogieron información sobre avistamientos de walabíes en los registros oficiales, las redes sociales, y los periódicos. Gracias a lo monos e inusuales que son, los avistamientos suelen ser mencionados en los periódicos locales.

En su artículo reciente publicado en la revista científica Ecologia y Evolución, los investigadores encontraron pequeñas poblaciones de walabíes viviendo a lo largo del sur de Inglaterra. Aunque alguno de estos animales es probablemente un fugitivo moderno de una colección privada o un zoo, es improbable que tales escapadas sean el origen de todos los avistamientos de la región. Por ello, los investigadores creen que las poblaciones del sur de Inglaterra se están reproduciendo en libertad.

Así que, si alguna vez estas en el sur de Inglaterra y crees que has visto a un walabí, ¡no te sorprendas demasiado!

Research demonstrates speech-in-noise training helps children with auditory processing disorder

Children with APD have difficulty perceiving speech when there is background noise and may have trouble on cognitive tests

Stephanie Santo

Psychology

Deep sea bacteria use selfishness to their advantage

Some bathypelagic bacteria have found a way to maximize their energy intake by taking food into their cells before breaking it down

Sarah Brown

Marine Science

University of North Carolina - Chapel Hill

The screen you are reading this on is probably emitting volatile organic compounds

A new study demonstrates that, in addition to a variety of other household products, LCD screens also emit these compounds

Kay McCallum

Atmospheric Chemistry

McMaster University

We spend a lot of time indoors - so it’s important that we know what’s in indoor air. Indoor chemists are especially concerned with volatile organic compounds (VOCs, a class of molecules that includes benzene, formaldehyde, and more), which can be harmful to human health and are highly reactive.

VOCs are released into indoor air from a number of sources – plants, wall paint, cooking and cleaning – and, as a recent study by a pair of researchers at the University of Toronto shows, from LCS screens like those in your phone, TV, and laptop.

To measure how LCD screens affect air quality, the researchers collected data on what types of compounds were contained in two types of samples: one of regular indoor air, and one collected near the surface of on an LCD screen like a new TV or an old laptop. They identified the chemical signatures of those compounds using a technique called proton-transfer reaction mass spectrometry. They then cross-referenced these signatures against lists of known liquid crystal monomers (the “building blocks” of LCD screens) and other compounds used in LCD screen manufacturing.

They found over 30 VOCs and 10 L liquid crystal monomers were heavily emitted into the air exposed to the screen, including extremely reactive species like isoprene and acetic acid. This finding indicates that LCD screens are an important source of VOCs in indoor environments, and that our screen-time may be exposing us to more than just new things on the internet.

Getting vaccinated against COVID-19 improves mental health

People who received the COVID-19 vaccine experienced less depression and anxiety compared to unvaccinated individuals

Danielle Llaneza

Health and Medicine

Hunter College and MD Anderson Cancer Center

Don’t bank those seeds — some oaks can be “cryopreserved”

Acorns can’t be frozen, but tips of oak tree shoots can

Christina Del Greco

Genetics and Genomics

University of Michigan

Male and female mice form memories of fearful events differently

A drug that blocks memory forming in male mice has a different effect in females

Rita Ponce

Evolutionary Biology

Polytechnic Institute of Setúbal

Psilocybin reduced depression symptoms as much as a leading antidepressant

New research compared the “magic mushrooms” component to Lexapro

Soren Emerson

Neuroscience

Vanderbilt University

Cocaine use slices and dices RNA in mouse brain cells

The analysis of epigenetic changes caused by cocaine use adds to the evidence that substance use disorders are rooted in biology

Anna Rogers

Molecular Biology

UC Berkeley

Your gut bacteria may be hoarding your medication

Researchers have observed this effect in petri dishes and nematodes

Madeline Barron

Microbiology

University of Michigan

Meet the springhare: the first glow-in-the-dark African mammal known to science

Researchers discovered the springhare’s fluorescent abilities entirely by accident

Shakira Browne

Zoology

University College Dublin

Fluorescence is caused by an animal absorbing light and bouncing it back out again, and in nature, it’s not a new thing. Fluorescence occurs across only a handful of mammals but they span three different continents and inhabit entirely different ecosystems. The platypus is one such animal, whose glow-in-the-dark abilities were only discovered in 2020. 

But, a discovery earlier this year by Northland College researchers that springhares fluoresce is special: it is the first documented case of biofluorescence in an Afro-Eurasian placental mammal. The study purports that perhaps fluorescence in mammals is not as rare as once previously thought. 

The researchers entered Chicago’s Field Museum of Natural History armed with a flashlight, with the goal of examining the fluorescent abilities of flying squirrels. Along the way, they accidentally discovered that springhares also glow. One specimen they examined was collected in 1905, and continued to glow in the dark for over 100 years.

The researchers subsequently tested live springhares (this time, in the dead of night—springhares are nocturnal) and found they could also fluoresce, predictably stronger than in the dead specimens. This study raises the questions: What other animals are out there, pulsating in every different shade of the rainbow after the clock strikes midnight? 

For the first time ever, researchers have “housebroken” cows

Controlling where cow waste ends up could lead to cleaner air and water and decreased greenhouse gas emissions

Fernanda Ruiz Fadel

Animal Behavior and Behavioral Genetics

Advanced Identification Methods GmbH

Feeding extra amino acids to cells with a mutated enzyme makes them grow faster

This new finding could lead to advances in treatment of diseases caused by ARS mutations

Christina Del Greco

Genetics and Genomics

University of Michigan

White pine blister rust’s habitat range is changing with the climate

New study in Sequoia and Kings Canyon National Parks demonstrates the complexity of changing plant-pathogen interactions

Ornob Alam

Population Genetics

New York University

These uses of poop for protection are stranger than fiction

Defense by dung doesn’t always elicit disgust in predators to repel them

Simon Spichak

Neuroscience

Distance and our eyes distort the true colors of stars

New research calculates the colors of stars based on their actual energy distributions

Briley Lewis

Astronomy and Astrophysics

University of California, Los Angeles

Zebrafish without “love hormone” neurons show no desire to socialize with each other

New research shows the importance of oxytocin for social affiliation and isolation

Kareem Clark

Neuroscience

Virginia Polytechnic Institute and State University

Wild Goffin’s cockatoos can use tools, too

Scientists have observed captive cockatoos making tools before, but this is the first documented instance of tool use in wild cockatoos

Fernanda Ruiz Fadel

Animal Behavior and Behavioral Genetics

Advanced Identification Methods GmbH

Giant clams are growing faster than ever. That’s not a good thing

This supercharged growth is likely due to nitrate aerosols in our modern atmosphere

Sarah Heidmann

Fish Ecology

University of the Virgin Islands

The growth of modern giant clams is supercharged compared to growth measured from fossil clams. A recent study from the Red Sea has shown this, finding that growth lines from modern species are larger than those of fossils from similar animals dated to the Holocene and Pleistocene.

These increased growth rates appear to be related to higher amounts of nitrate aerosols in the modern atmosphere. These come from many different sources. Some are natural, such as lightning, biomass burning, and soil processing, but most are from anthropogenic activity like burning fossil fuels and agricultural fertilization.

This fast growth may seem like a good thing, but growth doesn’t mean anything about the overall health of the clams. Additionally, aerosols may actually reduce the productivity of marine phytoplankton, which represent almost half of the world’s primary production.

The overall effects of nitrate and other aerosol pollution on global land and ocean cycles are not well understood. They may appear to reduce global warming by improving carbon dioxide uptake and reflecting the sun’s heat, but they contribute to poor air quality. We can congratulate today’s super clams on their impressive growth. But in the long run, fewer emissions on our part are probably better for them.

More Lab Notes →