Waves are ubiquitous in nature and technology. Whether it’s the rise and fall of ocean tides or the swinging of a clock’s pendulum, the predictable rhythms of waves create a signal that is easy to track and distinguish from other types of signals.
Electronic devices use radio waves to send and receive data, like your laptop and Wi-Fi router or cellphone and cell tower. Similarly, scientists can use a different type of wave to transmit a different type of data: signals from the invisible processes and dynamics underlying how cells make decisions.
The oscillating behavior of waves is one reason they’re powerful patterns in engineering.
For example, controlled and predictable changes to wave oscillations can be used to encode data, such as voice or video information. In the case of radio, each station is assigned a unique electromagnetic wave that oscillates at its own frequency. These are the numbers you see on the radio dial.
Waves can be modulated to carry different types of information, such as FM and AM radio.
Scientists can extend this strategy to living cells. My team used waves of proteins to turn a cell into a microscopic radio station, broadcasting data about its activity in real time to study its behavior.
Turning cells into radio stations
Studying the inside of cells requires a kind of wave that can specifically connect to and interact with the machinery and components of a cell.
Bacterial proteins MinD (cyan) and MinE (magenta) can self-organize into spiral patterns.
While electronic devices are built from wires and transistors, cells are built from and controlled by a diverse collection of chemical building blocks called proteins. Proteins perform an array of functions within the cell, from extracting energy from sugar to deciding whether the cell should grow.
Protein waves are generally rare in nature, but some bacteria naturally generate waves of two proteins called MinD and MinE – typically referred to together as MinDE – to help them divide. My team discovered that putting MinDE into human cells causes the proteins to reorganize themselves into a stunning array of waves and patterns.
On their own, MinDE protein waves do not interact with other proteins in human cells. However, we found that MinDE could be readily engineered to react to the activity of specific human proteins responsible for making decisions about whether to grow, send signals to neighboring cells, move around and divide.
Putting MinDE into human cells produces visual patterns that can signal changes to protein activity in the cell.
The protein dynamics driving these cellular functions are typically difficult to detect and study in living cells because the activity of proteins is generally invisible to even high-power microscopes. The disruption of these protein patterns is at thecore of many cancers and developmental disorders.
We engineered connections between MinDE protein waves and the activity of proteins responsible for key cellular processes. Now, the activity of these proteins trigger changes in the frequency or amplitude of the protein wave, just like an AM/FM radio. Using microscopes, we can detect and record the unique signals individual cells are broadcasting and then decode them to recover the dynamics of these cellular processes.
We have only begun to scratch the surface of how scientists can use protein waves to study cells. If the history of waves in technology is any indicator, their potential is vast.
Is your green my green? Probably not. What appears as pure green to me will likely look a bit yellowish or blueish to you. This is because visual systems vary from person to person. Moreover, an object’s color may appear differently against different backgrounds or under different lighting.
These facts might naturally lead you to think that colors are subjective. That, unlike features such as length and temperature, colors are not objective features. Either nothing has a true color, or colors are relative to observers and their viewing conditions.
There is a surprising amount of variation in how people perceive the world. If you offer a group of people a spectrum of color chips ranging from chartreuse to purple and asked them to pick the unique green chip – the chip with no yellow or blue in it – their choices would vary considerably. Indeed, there wouldn’t be a single chip that most observers would agree is unique green.
Generally, an object’s background can result in dramatic changes in how you perceive its colors. If you place a gray object against a lighter background, it will appear darker than if you place it against a darker background. This variation in perception is perhaps most striking when viewing an object under different lighting, where a red apple could look green or blue.
Of course, that you experience something differently does not prove that what is experienced is not objective. Water that feels cold to one person may not feel cold to another. And although we do not know who is feeling the water “correctly,” or whether that question even makes sense, we can know the temperature of the water and presume that this temperature is independent of your experience.
Similarly, that you can change the appearance of something’s color is not the same as changing its color. You can make an apple look green or blue, but that is not evidence that the apple is not red.
For comparison, the Moon appears larger when it’s on the horizon than when it appears near its zenith. But the size of the Moon has not changed, only its appearance. Hence, that the appearance of an object’s color or size varies is, by itself, no reason to think that its color and size are not objective features of the object. In other words, the properties of an object are independent of how they appear to you.
That said, given that there is so much variation in how objects appear, how do you determine what color something actually is? Is there a way to determine the color of something despite the many different experiences you might have of it?
Matching colors
Perhaps determining the color of something is to determine whether it is red or blue. But we suggest a different approach. Notice that squares that appear to be the same shade of pink against different backgrounds look different against the same background.
The smaller squares may appear to be the same color, but if you compare them with the strip of squares at the bottom, they’re actually different shades. Shobdohin/Wikimedia Commons, CC BY-SA
It’s easy to assume that to prove colors are objective would require knowing which observers, lighting conditions and backgrounds are the best, or “normal.” But determining the right observers and viewing conditions is not required for determining the very specific color of an object, regardless of its name. And it is not required to determine whether two objects have the same color.
To determine whether two objects have the same color, an observer would need to view the objects side by side against the same background and under various lighting conditions. If you painted part of a room and find that you don’t have enough paint, for instance, finding a match might be very tricky. A color match requires that no observer under any lighting condition will see a difference between the new paint and the old.
Is the dress yellow and white or black and blue?
That two people can determine whether two objects have the same color even if they don’t agree on exactly what that color is – just as a pool of water can have a particular temperature without feeling the same to me and you – seems like compelling evidence to us that colors are objective features of our world.
Colors, science and indispensability
Everyday interactions with colors – such as matching paint samples, determining whether your shirt and pants clash, and even your ability to interpret works of art – are hard to explain if colors are not objective features of objects. But if you turn to science and look at the many ways that researchers think about colors, it becomes harder still.
For example, in the field of color science, scientific laws are used to explain how objects and light affect perception and the colors of other objects. Such laws, for instance, predict what happens when you mix colored pigments, when you view contrasting colors simultaneously or successively, and when you look at colored objects in various lighting conditions.
The philosophers Hilary Putnam and Willard van Orman Quine made famous what is known as the indispensability argument. The basic idea is that if something is indispensable to science, then it must be real and objective – otherwise, science wouldn’t work as well as it does.
For example, you may wonder whether unobservable entities such as electrons and electromagnetic fields really exist. But, so the argument goes, the best scientific explanations assume the existence of such entities and so they must exist. Similarly, because mathematics is indispensable to contemporary science, some philosophers argue that this means mathematical objects are objective and exist independently of a person’s mind.
Likewise, we suggest that color plays an indispensable role in evolutionary biology. For example, researchers have argued that aposematism – the use of colors to signal a warning for predators – also benefits an animal’s ability to gather resources. Here, an animal’s coloration works directly to expand its food-gathering niche insofar as it informs potential predators that the animal is poisonous or venomous.
In fact, animals can exploit the fact that the same color pattern can be perceived differently by different perceivers. For instance, some damselfish have ultraviolet face patterns that help them be recognized by other members of their species and communicate with potential mates while remaining largely hidden to predators unable to perceive ultraviolet colors.
In sum, our ability to determine whether objects are colored the same or differently and the indispensable roles they play in science suggest that colors are as real and objective as length and temperature.
Many bakers working at high altitudes have carefully followed a standard recipe only to reach into the oven to find a sunken cake, flat cookies or dry muffins.
Experienced mountain bakers know they need a few tricks to achieve the same results as their fellow artisans working at sea level.
These tricks are more than family lore, however. They originated in the early 20th century thanks to research on high-altitude baking done by Inga Allison, then a professor at Colorado State University. It was Allison’s scientific prowess and experimentation that brought us the possibility of perfect high-altitude brownies and other baked goods.
We are two current academics at CSU whose work has been touched by Allison’s legacy.
One of us – Caitlin Clark – still relies on Allison’s lessons a century later in her work as a food scientist in Colorado. The other – Tobi Jacobi – is a scholar of women’s rhetoric and community writing, and an enthusiastic home baker in the Rocky Mountains, who learned about Allison while conducting archival research on women’s work and leadership at CSU.
Inga Allison is one of the fascinating and accomplished women who is part of the exhibit.
Allison was born in 1876 in Illinois and attended the University of Chicago, where she completed the prestigious “science course” work that heavily influenced her career trajectory. Her studies and research also set the stage for her belief that women’s education was more than preparation for domestic life.
In 1908, Allison was hired as a faculty member in home economics at Colorado Agricultural College, which is now CSU. She joined a group of faculty who were beginning to study the effects of altitude on baking and crop growth. The department was located inside Guggenheim Hall, a building that was constructed for home economics education but lacked lab equipment or serious research materials.
Allison took both the land grant mission of the university with its focus on teaching, research and extension and her particular charge to prepare women for the future seriously. She urged her students to move beyond simple conceptions of home economics as mere preparation for domestic life. She wanted them to engage with the physical, biological and social sciences to understand the larger context for home economics work.
Such thinking, according to CSU historian James E. Hansen, pushed women college students in the early 20th century to expand the reach of home economics to include “extension and welfare work, dietetics, institutional management, laboratory research work, child development and teaching.”
News articles from the early 1900s track Allison giving lectures like “The Economic Side of Natural Living” to the Colorado Health Club and talks on domestic science to ladies clubs and at schools across Colorado. One of her talks in 1910 focused on the art of dishwashing.
Allison became the home economics department chair in 1910 and eventually dean. In this leadership role, she urged then-CSU President Charles Lory to fund lab materials for the home economics department. It took 19 years for this dream to come to fruition.
In the meantime, Allison collaborated with Lory, who gave her access to lab equipment in the physics department. She pieced together equipment to conduct research on the relationship between cooking foods in water and atmospheric pressure, but systematic control of heat, temperature and pressure was difficult to achieve.
She sought other ways to conduct high-altitude experiments and traveled across Colorado where she worked with students to test baking recipes in varied conditions, including at 11,797 feet in a shelter house on Fall River Road near Estes Park.
But Allison realized that recipes baked at 5,000 feet in Fort Collins and Denver simply didn’t work in higher altitudes. Little advancement in baking methods occurred until 1927, when the first altitude baking lab in the nation was constructed at CSU thanks to Allison’s research. The results were tangible — and tasty — as public dissemination of altitude-specific baking practices began.
As a senior food scientist in a mountain state, one of us – Caitlin Clark – advises bakers on how to adjust their recipes to compensate for altitude. Thanks to Allison’s research, bakers at high altitude today can anticipate how the lower air pressure will affect their recipes and compensate by making small adjustments.
Air pressure is a force that pushes back on all of the molecules in a system and prevents them from venturing off into the environment. Heat plays the opposite role – it adds energy and pushes molecules to escape.
When water is boiled, molecules escape by turning into steam. The less air pressure is pushing back, the less energy is required to make this happen. That’s why water boils at lower temperatures at higher altitudes – around 200 degrees Fahrenheit in Denver compared with 212 F at sea level.
So, when baking is done at high altitude, steam is produced at a lower temperature and earlier in the baking time. Carbon dioxide produced by leavening agents also expands more rapidly in the thinner air. This causes high-altitude baked goods to rise too early, before their structure has fully set, leading to collapsed cakes and flat muffins. Finally, the rapid evaporation of water leads to over-concentration of sugars and fats in the recipe, which can cause pastries to have a gummy, undesirable texture.
Allison was one of many groundbreaking women in the early 20th century who actively supported higher education for women and advanced research in science, politics, humanities and education in Colorado.
Others included Grace Espy-Patton, a professor of English and sociology at CSU from 1885 to 1896 who founded an early feminist journal and was the first woman to register to vote in Fort Collins. Miriam Palmer was an aphid specialist and master illustrator whose work crafting hyper-realistic wax apples in the early 1900s allowed farmers to confirm rediscovery of the lost Colorado Orange apple, a fruit that has been successfully propagated in recent years.
In 1945, Allison retired as both an emerita professor and emerita dean at CSU. She immediately stepped into the role of student and took classes in Russian and biochemistry.
In the fall of 1958, CSU opened a new dormitory for women that was named Allison Hall in her honor.
Why don’t humans have hair all over their bodies like other animals? – Murilo, age 5, Brazil
Have you ever wondered why you don’t have thick hair covering your whole body like a dog, cat or gorilla does?
Humans aren’t the only mammals with sparse hair. Elephants, rhinos and naked mole rats also have very little hair. It’s true for some marine mammals, such as whales and dolphins, too.
Scientists think the earliest mammals, which lived at the time of the dinosaurs, were quite hairy. But over hundreds of millions of years, a small handful of mammals, including humans, evolved to have less hair. What’s the advantage of not growing your own fur coat?
I’m a biologist who studies the genes that control hairiness in mammals. Why humans and a small number of other mammals are relatively hairless is an interesting question. It all comes down to whether certain genes are turned on or off.
Hair benefits
Hair and fur have many important jobs. They keep animals warm, protect their skin from the sun and injuries and help them blend into their surroundings.
They even assist animals in sensing their environment. Ever felt a tickle when something almost touches you? That’s your hair helping you detect things nearby.
Humans do have hair all over their bodies, but it is generally sparser and finer than that of our hairier relatives. A notable exception is the hair on our heads, which likely serves to protect the scalp from the sun. In human adults, the thicker hair that develops under the arms and between the legs likely reduces skin friction and aids in cooling by dispersing sweat.
So hair can be pretty beneficial. There must have been a strong evolutionary reason for people to lose so much of it.
Why humans lost their hair
The story begins about 7 million years ago, when humans and chimpanzees took different evolutionary paths. Although scientists can’t be sure why humans became less hairy, we have some strong theories that involve sweat.
Humans have far more sweat glands than chimps and other mammals do. Sweating keeps you cool. As sweat evaporates from your skin, heat energy is carried away from your body. This cooling system was likely crucial for early human ancestors, who lived in the hot African savanna.
Of course, there are plenty of mammals living in hot climates right now that are covered with fur. Early humans were able to hunt those kinds of animals by tiring them out over long chases in the heat – a strategy known as persistence hunting.
Humans didn’t need to be faster than the animals they hunted. They just needed to keep going until their prey got too hot and tired to flee. Being able to sweat a lot, without a thick coat of hair, made this endurance possible.
Genes that control hairiness
To better understand hairiness in mammals, my research team compared the genetic information of 62 different mammals, from humans to armadillos to dogs and squirrels. By lining up the DNA of all these different species, we were able to zero in on the genes linked to keeping or losing body hair.
Among the many discoveries we made, we learned humans still carry all the genes needed for a full coat of hair – they are just muted or switched off.
In the story of “Beauty and the Beast,” the Beast is covered in thick fur, which might seem like pure fantasy. But in real life some rare conditions can cause people to grow a lot of hair all over their bodies. This condition, called hypertrichosis, is very unusual and has been called “werewolf syndrome” because of how people who have it look.
Petrus Gonsalvus and his wife, Catherine, painted by Joris Hoefnagel, circa 1575. National Gallery of Art
In the 1500s, a Spanish man named Petrus Gonsalvus was born with hypertrichosis. As a child he was sent in an iron cage like an animal to Henry II of France as a gift. It wasn’t long before the king realized Petrus was like any other person and could be educated. In time, he married a lady, forming the inspiration for the “Beauty and the Beast” story.
While you will probably never meet someone with this rare trait, it shows how genes can lead to unique and surprising changes in hair growth.
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