Author: Roberta (Page 499 of 561)

Meet a Scientist Monday: Dr. Minda Weldon, Epidemiologist

When I started Meet a Scientist Monday, I knew there was one person we just had to include because her work was so extremely interesting. Today we hear from Dr. Minda Weldon, who is an epidemiologist.

1. What is an epidemiologist?

Most people know that epidemiologists study outbreaks of infectious diseases (there are lots of epidemiologists scrambling to study swine flu right now!), but they do a lot more, too. Epidemiologists study cancer, birth defects, exposure to possible environmental toxins, injuries, food poisoning and much more. Some epidemiologists specialize in doing studies to see if new medicines really work. Most hospitals employ an epidemiologist to make sure that infections are not accidentally spread among patients. Lots of epidemiologists are also trained as medical doctors, veterinarians, nurses, and dentists. While a medical doctor’s patient is one person, an epidemiologist’s “patient” is a whole population. Sometimes it is really hard to tell what has made someone sick, so epidemiologists collect information from lots and lots of people (sometimes thousands and thousands) to get answers.

2. How did you decide to become an epidemiologist?

I first became interested in epidemiology when I was in high school. When I was sixteen years old, I had the wonderful opportunity to volunteer with a public health and youth development organization called Amigos de las Americas. I lived in a rural village in the state of Guanajuato, Mexico, and my job was to teach the locals why it was it was important to use and build latrines, and to teach mothers how to care for people suffering from diarrhea. Most people in the United States get diarrhea once in a while and consider it uncomfortable and inconvenient. Where I worked in Mexico, diarrhea was frequent and could be life threatening, especially for babies and young children. Flies landed on animal and human “droppings” and then landed on food, transmitting diseases. Clean water was not available for cooking or hand washing. It was pretty easy to figure out how diseases were being spread. In my first week in the village, my host family’s malnourished baby came very, very close to dying as a consequence of severe diarrhea and dehydration.

Later, when I was nineteen, I worked with the same organization on a rabies eradication program in Ecuador. I worked with Ecuadorian veterinarians and doctors. I still remember the map with red-topped pins noting each reported case of rabies. I saw how the epidemiologists studied the spread of the disease and determined which areas needed the vaccine the most. Because of this careful study and planning the number of cases of rabies (in humans and animals) plummeted. I decided I wanted to be an epidemiologist.

3. How did you become an epidemiologist?

I received a PhD in epidemiology of the University of California at Davis. After I finished my bachelor’s degree (in four years), it took me almost four more years to get my PhD. I studied lots of different things including biology, chemistry, and lots of statistics. I also worked closely with a professor to do a research study about how different diseases affect the ability of older people to live independently.

4. What was your most exciting job?

After I got my PhD, I spent two years as an Epidemic Intelligence Service (EIS) officer for the Centers for Disease Control and Prevention. It was a very exciting job! EIS officers investigate disease outbreaks all over the world. EIS officers were some of the first scientists to investigate HIV and ebola and toxic shock syndrome.

One of my investigations was of an unusual case of mercury poisoning. It turned out that a popular Mexican beauty cream contained high levels of mercury. People loved the cream because it got rid of their acne (mercury can be a good antibacterial) but they didn’t know that it was also poisoning them! Some of the people who used the cream had strange health problems but they had no idea that the problems were being caused by a beauty cream. After the investigation, the company stopped making the cream.

5. What did you do on a day-to-day basis?

As an epidemiologist, I spent a lot of time at the computer analyzing data and then writing reports and medical journal articles. I also interviewed people and collected information on surveys. Sometimes I had to draw blood. I toured a greenhouse full of poinsettias to try to figure out how workers had been sickened by a pesticide. I went to waste water treatment facilities to get a feel for how much exposure workers had to untreated sewage (a lot!) so that I could design a study to see if workers would benefit from a new vaccine. You see, I was always doing something new.

Wow, Dr. Weldon’s job sounds difficult, but also very rewarding. An epidemiologist saves people’s lives. After reading her answers, are you interested in becoming an epidemiologist? If so, you will need to work hard on math and science.

Resources for more information, provided by Dr. Weldon:

This link has various information about epidemiology, much of which is geared to teachers.
http://www.cdc.gov/excite/index.htm

This link has some fun games about epidemiology and germs
http://medmyst.rice.edu/

A Science Friday (National Public Radio) Kids’ Connection about John Snow, the father of epidemiology
http://www.kidsnet.org/sfkc/sfkc20040924-2.html#links

A link to the organization I volunteered with when I was in high school and college
http://www.amigoslink.org/

Weekend Science Fun: Insect Architects

Do you have any idea what the hummingbird and the paper wasp from the two previous posts have in common? Answer:  both construct interesting and complex nests without the benefit of opposable thumbs.  Have you ever wondered how animals make some of their incredible homes? Let’s take a look at some insect architects this week, and possibly get some ideas for our own construction.

1.    Paper Wasps and Hornets

paper wasp

At least 22 species of paper wasps are found in North America and hundreds more species worldwide. They are social insects, which means one female lays the eggs and her daughters help her take care of the resulting offspring.

The paper wasps get their name from the fact they build a nest of a papery material made of thin wood strips and saliva mixed together. Paper wasp nests may be found under eaves or hidden within dense shrubs. Example paper wasp nest

The paper wasps usually construct their nest on a slender stalk and it looks sort of like an upside-down umbrella. The base of the nest contains openings or “cells” where the eggs are laid, and the larvae and pupae are cared for.

Paper wasp inspired activities:

  • Paper wasp coloring sheet
  • Papermaking with recycled paper
  • Construct a paper house. You can fold and decorate a paper house as described here.
  • Can paper be used to build actual houses for humans? People are starting to try different paper mixtures. One, called “papercrete,” has already been used to make real houses. Here is a photo of bricks made of paper used to make a house in Phoenix.

bricks made of paper

  • Design and build your own paper house. Be sure to think outside the box, so to speak. Try paper bags, cardboard egg cartons, etc and create new building shapes. I’d love to see what you come up with.

2.    Bumble bees

Bumble bees are large, fuzzy bees that are often yellow and black. They are social, which means they live in groups with a queen that lays the eggs and her daughters that help her, just like the paper wasps.

Bumble bee nests are made of a waxy material, like the wax honeycombs of honey bees, except the cells are oval and are not at all uniform in size or shape.  Bumble bees typically nest in the ground, for example in abandoned mouse burrows.

Bumble bee inspired activities:

  • Bumble bee coloring sheet
  • Building
    Design and try to make a building out of soap bars, modeling clay or beeswax, if available. How does this material differ from the paper you used above? Does its softness limit the shapes you can make?

3.    Honey bees

Honey bees make elaborate honeycombs out of a wax they secrete themselves.

honeycomb

honey bee combs

Generally honey bees build this comb within an enclosure, such as a hollow tree. Honey bees maintained by people build their comb inside special wooden frames inside a hive box.

Honey bee inspired activities:

Bee Hives and Skeps
Do you know what a skep is? You may have seen these old-fashioned beehives used as decorations. They are coils of straw or dried grass twisted into a dome or bell shape.

bee skep bottle

Gather some crafting raffia or similar materials. Coil the raffia in a circle to make the base and then fix by sewing or with hotmelt glue. Continue to coil the next layers in increasingly smaller circles until you have created a skep shape. Either paint with bees or craft some bees for decorations.

Geometry:
Why are honey bee cells in the honeycomb in the shape of hexagons? Can you come up with a better shape? Remember that the larvae inside are rounded. Check this link for hints.
http://ag.arizona.edu/pubs/insects/ahb/act18.gif

4.    Ants

Because they often live underground, we might not give as much thought to the nests constructed by ants. Dr. Walter Tschinkel has modified an older technique for looking at the structure of ant nests by pouring dental plaster into the tunnels, allowing it to dry and then digging up the nest, giving a negative-space impression of some truly impressive ant nests.

Dr. Walter Tschinkel’s Ant Castles can be found at the Florida State University. He’s says that the ants can build the huge one at the bottom in just five days!

Ant inspired activities:

  • Watch ants build tunnels in a homemade ant farm
  • Design and draw plans for an underground home. What would be the advantages of living underground? What might some of the problems be?

Books for more ideas and information:

Roberto, The Insect Architect by Nina Laden

Roberto is an incredibly fun fiction picture book, both for those interested in architecture and those interested in insects.

Nonfiction:
Hornets: Incredible Insect Architects (Insect World) by Sandra Markle

Burrows, Nests & Lairs: Animal Architects by Lark Books (Editor)

Animal Architects by John Nicholson

This award-winning book covers many Australian animals.

Animal Architects – How Insects Build Their Amazing Homes by W. Wright Robinson

Disclosure: I am an affiliate for Amazon. If you click through the linked titles or ads and make a purchase, I will receive a small commission at no extra charge to you. Proceeds will be used to maintain this self-hosted blog.

Bug of the Week: Paper Wasp

This morning it has been partly cloudy, but during a burst of sunshine I was able to catch a photo of this paper wasp, Polistes flavus.

paper wasp

Any idea what she might be doing?

paper wasp

Look how shiny she is. Her eyes are shaped like kidney beans. She has three smaller eyes called ocellae in a triangle at the top of her head.

She was hunting for caterpillars and other insects. Wasps feed their young larvae bits of insects they catch and bring back to their extraordinary paper nests.

You might wonder whether I was in any danger taking this photo. In fact, this species of paper wasp that we encounter in Arizona is surprisingly unassuming. Unless you directly threaten their nest, they are not likely to sting. Their nests are often hidden in the dense foliage in small shrubs, such as rosemary bushes or under red yucca (hesperaloe) in our yard. We are much more likely to be stung by bees than these wasps.

I have noticed several paper wasps around my mint plants lately. I hope they are catching the cabbage loopers that have been devastating the plants. Go wasps, go.

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