Stories tagged Life Science

Nov
03
2006

All week, the comic strip "Non Sequitur" has been running gags about whether or not a duck's quack echoes. The joke is that once someone asks you the question, you can't stop thinking about it until you know the answer. It's Friday, and I've resisted the temptation to look it up until now, but I've caved!

I can't think of a single scientific reason why a duck's quack WOULDN'T echo, but I had to look it up anyway. The good news? I'm hardly the first person to do it. When I googled "Does a duck's quack echo?" I got 105,000 hits, including links to some real research.

Here are some of the best sources of info:

BBC news: "Sound science is quackers"

Salford University: "The duck's quack echo myth" (This is an awesome page.)

The Straight Dope: "Is it true a duck's quack won't echo?"

Science Made Simple: Does a duck's quack echo?"

About.com (Urban Legends and Folklore): "A duck's quack doesn't echo"

MadSci Network: "Why won't the quack of a duck echo?"

SPOILER: Yes, a duck's quack, like any other sound, echoes. But the WAY a duck quacks, with the long "AAAAAACK" sound at the end of the call, tends to mask echoes, making them hard to hear.

Oct
26
2006

A manatee: Photo courtesy US Geologic Survey
A manatee: Photo courtesy US Geologic Survey

Rescuers from the US Fish and Wildlife Service are trying to capture a manatee that has strayed far from home. These large, gentle creatures normally live in the Gulf of Mexico. But one half-ton hombre swan 700 miles up the Mississippi River and is now inhabiting the harbor at Memphis, Tennessee!

Scientists are concerned for the animal's health. Nearly hairless, manatees need water 68 degrees or warmer. The river is a little bit chillier than that, and biologists worry that the creature’s digestive system could shut down. They are trying to corral it and move it to Sea World Florida, where it can receive medical attention.

Oct
26
2006

Dermestid colony: (Courtesy US FWS)
Dermestid colony: (Courtesy US FWS)

First of all, check out the Museum's dermestid cam. (Dermestid beetles are scavengers—organisms that eat the remains and wastes of other plants and animals.)

If you're at the museum, go to the Science Buzz station in the Mississippi River Gallery on Level 5 to watch a live feed from the dermestid colony. Or, even better, you can look into the colony itself from the queue for the 3D theater, down by the Triceratops on Level 3.

It's a dirty job, but someone has to do it.
Rot happens. And scavengers—like dermestid beetles and turkey vultures—eat rotting things. We associate rot with death, but it also makes life possible. How? As dead plants and animals decay—helped along by scavengers—the nutrients inside their bodies are returned to the soil. That helps new plants grow and starts the food chain over again. Without scavengers and decomposers, we’d be up to our necks in dead stuff. Think of them as the ultimate recyclers!

Bad to the bone
Adult dermestid beetles are small, black, and hairy with patches of white. The brownish-gold larvae have blunt heads and tufts of long brown hair on their rear ends. And they’re hungry—an infestation of dermestid beetles can destroy a museum’s collections. So why does the Museum keep a dermestid colony? The insects eat old, dried out, mummified stuff—leather, fur, feathers, skin, hair, wool, silk, and dried food products. They eat it all, right down to the bone. So they’re valuable for cleaning skeletons.

Many insects lay eggs and develop on dead bodies, eating them as they go. Blow flies—among the first to colonize a body—come and go fairly quickly. Dermestids, on the other hand, can be found around a body as long as there’s anything to eat—from near the time of death to years later. The kinds of insects that a scientist finds with a corpse, and the ages of the larvae and pupae, can be used to estimate when the death occurred. So insect scavengers can also help solve crimes.

Young blowfly maggots on a rat carcass: Photo courtesy Aaron Tarone
Young blowfly maggots on a rat carcass: Photo courtesy Aaron Tarone

Set up a beetle habitat of your own
It’s easy to observe the transformation of complete metamorphosis when you set up your own mealworm colony. Mealworms, the larval form of darkling beetles, are commonly sold in pet stores as food for reptiles and amphibians. These beetles are completely harmless and cannot bite or run very fast. As long as they're well fed, adult beetles won't try to escape their habitat.

Materials

  • A large plastic bin, 2–3” deep
  • A bag of oat or wheat bran
  • Two layers of burlap or cheesecloth, cut to fit inside the bin
  • Light all-purpose household oil to coat the outside edges of the bin when the beetles mature
  • Approximately 50 mealworms, available at pet stores or bait shops

What to do

  1. Lay a square of burlap in the tray.
  2. Pour 1–2” of bran into the tray.
  3. Add the mealworms.
  4. Lay a square of burlap or cheesecloth on top of the bran. (This gives the older larvae a place to pupate.)
  5. Add a fresh slice of apple, potato, or lettuce on top of the bran every week. This will provide all the moisture your mealworms need. Add fresh bran as the level goes down.

Simple experiments
Develop some simple experiments to observe behaviors and record major events in the mealworms’ life cycle:

  1. Measure individual mealworms weekly and record growth rates on a graph.
  2. Place a few “control” mealworms in the refrigerator to see if they develop at the same rate.
  3. Place mealworms in the centers of some Styrofoam meat trays. Cover half of each tray with black construction paper, and hypothesize whether the mealworms will move to the light side or the dark side of the tray.
  4. Record the number of times the mealworm molts, or sheds its exoskeleton, as it grows.
  5. Record the number of weeks until their mealworms pupate, and how long they remain in the pupae.
Oct
12
2006

Stop bleeding fast: photo by crystal via wikimedia
Stop bleeding fast: photo by crystal via wikimedia

Super quick fix for bleeding.

Last June 4th, I reported that MIT researchers used a self-assembling peptide nanofiber scaffold to repair severed brain structures in blind rodents and restore their sight. Those same researchers noticed the material's dramatic ability to stop bleeding in the brain and began testing it on a variety of other organs and tissues.

In a study published online October 10 in Nanomedicine the researchers report that the liquid controlled bleeding in rodents within 15 seconds in seven other wound types, including cuts to the spinal cord, liver [view video here] and femoral artery as well as skin punctures.

Platelets not needed

The liquid does not seem to form a conventional blood clot, the group notes. Electron microscopy turned up no sign of the platelets that would normally gather in a clot. The proteins might instead form tangles that act like hair blocking a drain, Ellis-Behnke suggests.
The gel eventually breaks down into amino acids, the building blocks of proteins, that can be used by surrounding cells for tissue repair.

This discovery has created lots of excitement, especially by surgeons. Still, they caution that extensive clinical trials are needed to make sure the materials work properly and are safe. The MIT researchers hope to see those crucial human trials within three to five years.

Read more at: New Scientist Tech and Scientific American

Oct
05
2006

Skipjack herring: Illustration courtesy Duane Raver and the U.S. Fish and Wildlife Service.
Skipjack herring: Illustration courtesy Duane Raver and the U.S. Fish and Wildlife Service.

I work at the Science Museum and I often learn unusual things during the course of my day. Some things are funny, some I store away to pull out in a Cliff Claven moment, and others make me want to run screaming to my desk to put them into this blog.

This is one of the latter.

Yesterday I learned that herrings may communicate with one another through their anuses by farting. I almost exploded when the person leading the meeting casually mentioned this fact. I ran back to my computer, and sure enough. Researchers at not one, but TWO institutions are studying the phenomena. Both the Institute of Coastal Research at the National Board of Fisheries in Sweden and the University of British Columbia, Vancouver have researchers looking into the matter.

Before this remarkable discovery, it was known that herrings communicated with one another through sounds produced by their swim bladder. Researchers thought that all the sounds they heard coming from the herring were coming from the swim bladder. But, and I am laughing as I type, they noticed that a stream of bubbles would leave the herring’s anus in time with the sounds they were hearing. Sure enough, they are connected, and that sound was soon dubbed by the quick-thinking researchers as a Fast Repetitive Tick (or FRT, if you will).

Researchers note that the unlike the gas we pass, these sounds are not produced by the digestive process, but rather a connection between the swim bladder and the anus. The exact purpose or reason behind the FRTs is not exactly known. One theory is that is a way for the herring to communicate with each other at night. Another is that is an anti-predator tactic. Seriously. Or, it could just be an incidental release of air from the swim bladder as the fish adjusts its buoyancy.

You can hear the herring communicating in this manner here.

Oct
02
2006


Pine Barrens Tree Frog: In this image the tympanum can be seen as the small round disk to the right of the eye. Image courtesy Bruce Means and the U.S. Fish and Wildlife Service.
Do frogs have ears?

Yes, they do, but they are different from the ears we have. Frogs do not have external ears, rather they have something called a tympanum. The tympanum are behind the eyes, and look like round disks. Some tympanum are easier to see than others. They receive sound waves for the frog just like the tympanic membrane (also known as the eardrum) does for us. Frogs not only use the tympanum to hear, but also use their lungs. The lungs help with hearing, and also protect the frog’s eardrums from the very loud noises frogs make by equalizing pressures between the inner and outer surfaces of the tympanum.

What does sublimation mean?

In physics, sublimation is the process by which a solid converts to a gas and bypasses a liquid stage in doing so. Have you ever seen dry ice? At room temperature, dry ice sublimates directly into a gas, skipping the liquid stage.

Where do Komodo Dragons live?

There are about 6,000 Komodo Dragons living in the wild. They live on the Lesser Sunda Islands in Indonesia.

What causes hiccups?

There are a variety of causes for hiccups, including eating too quickly, swallowing too much air, taking a cold drink while eating a hot meal, laughing, coughing, or drinking too much alcohol.

Hiccups are an involuntary spasm of the diaphragm, the large muscle that separates the chest cavity from the abdominal cavity. The sudden intake of air into the lungs is stopped by the glottis, which causes the “hic” sound.

Do you know how fast the Earth spins on its axis?

Well, if you figure the Earth does one full rotation on its axis about every 24 hours (23 hours, 56 minutes, and 04.09 seconds), and the Earth’s circumference is around 25,000 miles (24,901.55 miles), then it spins at roughly 1,040 miles per hour.

Illustration of the life-cycle of the Sun: Illustration courtesy Tablizer.
Illustration of the life-cycle of the Sun: Illustration courtesy Tablizer.Courtesy Tablizer
Will the sun explode?

No, but one day it will be large enough to push the Earth into a new orbit while eradicating the Earth’s atmosphere – but not for a long, long time. Our sun does not have enough mass to “go supernova” and explode. But, in about 5-6 billion years it will start becoming a red giant once it has used up its supply of hydrogen in its core and switched to fusing hydrogen in a shell outside of its core. While this is happening other processes will cause the sun to grow. Much, much later, the red dwarf will become a planetary nebula, and then a white dwarf. This is the standard stellar evolution for a star such as our sun.

Sep
27
2006

You're invited to attend the annual Fall Color Blast on Sunday, October 1, from 1-5pm, at the Warner Nature Center. The event is free and features a professional storyteller, live fiddle music, bird banding demonstrations, canoeing, rides on a solar-powered pontoon, hikes, kids' crafts, free apple pie and ice cream, cider and coffee, and more. (Want more information about programs at the Center?)

Sep
21
2006

Hawk watchers at Hawk Ridge: Photo courtesy Mark Ryan
Hawk watchers at Hawk Ridge: Photo courtesy Mark Ryan
Duluth, Minnesota is one of the best places in the Midwest for watching hawks and other birds of prey as they make their annual migration south for the winter.

Red-tailed Hawk in flight: Photo courtesy National Park Service.
Red-tailed Hawk in flight: Photo courtesy National Park Service.
Since the migrating birds avoid crossing large expanses of water, Lake Superior acts as a funnel, forcing them into Duluth where the lake narrows to its western point, and crossing is easier. This means that thousands of hawks and raptors fly over the region, coming down from Canada and other points north. One of the best sites to see them is at Hawk Ridge Nature Reserve, which is situated, in eastern Duluth at an overlook along the city’s Skyline Parkway.

The observation site draws not only vast numbers of birds (averaging over 94,000 per year) but also vast numbers of visitors who come each fall to watch the migration and enjoy the stunning panoramic views of Lake Superior and eastern Duluth.

If conditions are right, a lucky visitor may see Broad-wing Hawks, Osprey, Bald and Golden Eagles, Red-tailed and Rough-legged Hawks, American Kestrels, Northern Goshawks, and Peregrine Falcons. Great Horned and Long-eared Owls can also be seen at times.

The raptors can be seen just about everyday during Autumn, except when it’s raining, Generally, the birds begin migrating over Hawk Ridge in mid-August through November. The best time to spot them is when the wind is blowing in from the west or northwest for a couple of days straight. Official counters scan the skies with binoculars most days and tally the migration. During “The Big Days”, which generally take place between September 10-25, tens of thousands of Broad-winged Hawks can be spotted soaring over the ridge. This past week over 28,000 of them were counted in just two days!

For directions and further information visit the Hawk Ridge Bird Observatory website. Then pack up your binoculars and camera, and head north to Duluth.

Sep
21
2006

The CDC has more than 100 million doses of this year's flu vaccine available--enough so that anyone who wants one can get one. (Doctors and clinics will start receiving the vaccine next month.)

Last year 86 million doses were available, but 4.8 million went unused. Yet 200 million Americans are either considered high risk themselves or have close contact with someone at high risk and should consider getting the shot.

People on the CDC's priority list include:

  • Health care providers,
  • Children between 6 months and 5 years old,
  • People with chronic illnesses, such as diabetes, asthma, or heart disease,
  • And people older than 50.

It's best to get vaccinated in October or November so there's time for immunity to develop before the flu season hits. But numbers of influenza cases usually peak in February, so even a late shot offers some protection.

Every year somewhere between 5 and 20% of the US population catches influenza. 200,000 of them need hospital care, and 36,000 die.

So...will you be getting a flu shot this year? Vote in our poll, and tell us why or why not.

Sep
21
2006

Today the CDC announced its new recommendation that all Americans between the ages of 13 and 64 be routinely checked for HIV, the virus that causes AIDS. Why the change? About one million Americans are infected with HIV, but 25% of them have no idea that they're carrying the virus. Routine testing should help check the spread of the disease and preserve health as infections are caught earlier.

The CDC's recommendation isn't binding, but it does influence what doctors do and what health insurance covers. And the blanket recommendation might help reduce the stigma associated with HIV testing.

What do you think? Will you get screened for HIV at your next physical? Why or why not?