

1. What's your job title?
Extension Nematologist, Oregon State
University. My rank is Senior Faculty Research Assistant.
2. How did you feel about math when you were in
school?
I felt differently about different math subjects. In
gradeschool, I liked it in general (because I was supposed to be one of
the "smart kids".) In high school, I began with the attitude of liking
it,
but in algebra, my first class, I could never figure out how to factor
quadratic equations. In geometry, there was no algebra, and I loved
it,
understood it completely, and barely had to study. The teacher would
always call on me to put my answers up on the board after all the other
students goofed up. The next two years, junior and senior years in
high
school, we had some kind of advanced algebra or something. I never
understood it, and it was discouraging. I developed the opinion that I
was "bad in math." At OSU, I was placed in Analytic Geometry, which is
geometry based on quadratic equations. I did not do well in this, and
in
fact dropped the class and took two or three terms of remedial math,
and
then tried analytical geometry again. I didn't do very well, but I
liked
it because conic sections are so attractive. I also took a term of
calculus. I did so badly that no one ever suggested me taking another
term. My image of calculus is of a guy standing around tossing a
softball
in the air and catching it, because this is all I ever understood in
this
class.
3. How do you feel about it now?
I like math, and I think that if I
could work at the parts I struggle with more slowly, I would do OK. In
addition, I have had more recent successes in math-oriented classes.
For
my master's degree here at OSU, I had to take three terms of
statistics.
I was so afraid I was going to fail that I studied really hard.
I did well in two of
the three statistics classes, and I have used statistics since that
time
in writing scientific publications. Success helps to build confidence.
(However, I have no solution for a lack of success!)
4. Did you have to go to college to get this job?
Yes.
5. If so, for how long?
I went to OSU for four years for my
bachelor's
degree in botany and then, after several years, came back to OSU for
three
years to
complete a Master's of Science degree in Botany and Plant Pathology.
6. If so, what kind of math class
did you take?
(see above.)
7. What kind of math is in your
job?
1. Statistics (mostly things like Analysis of
Variance and t-tests and comparable non-parametric tests) for
publications. This is not an everyday thing - it's used more in the
set-up of experiments, which my boss does, and in the writing up
afterwards. I use these tools in personal projects, however,
especially regarding birds (see below). During the experiment itself,
the
work is usually mundane.
2. Arithmetic and a few descriptive statistics. Explanation: my job
is
to receive soil and plant samples from members of the public, to figure
out how many plant-parasitic nematodes are in the soil or plants, and
to
report this information back to the sender. (Nematodes are roundworms.
The ones that live in soil are from about 1/3 mm to 5 mm long. There
are
many nematodes living in soil that are NOT plant parasites; these feed
on
bacteria, fungi, or other small animals. All are important in cycling
nutrients in soil. A lot of people think of these as "bad" nematodes
versus "good" nematodes, but I prefer to be neutral and think of them
according to what they feed on. Plant-parasitic nematodes are members
of
natural systems, so they are not unexpected in crop plants. Because
crops
are a monoculture (one kind of plant growing over a whole big area), if
a
plant-parasitic nematode happens to like that plant, it will multiply
and
possibly damage the crop. Just thought you might like a little
background. OK, so I report the number of plant-parasitic nematodes in
terms of what would be in 100 g of soil corrected for soil moisture.
To
get this figure, I put 20 g of soil into a soil drying oven, dry it for
a
predetermined amount of time, and weigh it afterwards. It weighs less,
because all the water is gone. I divide 20 g by the dry weight, which
gives a number between 1 and 2. (Here's another way I used math. I
compared the price of a Soil Drying Oven with the price of a Bi-Mart
Toaster Oven, and the toaster oven cost about 1/10th as much as the
Soil
Drying Oven, so I chose the toaster oven.) In the meantime, I get the
nematodes out
of the soil - I won't bore you with the details. I count at least 100
of
each relevant kind in a gridded counting dish. The reason the grid is
there is so that the number of nematodes within a certain area can be
counted, and if you know what proportion of the total that area is, you
can figure out how many nematodes would be in the whole dish by
multiplying by the proper factor. We have a standardized counting
dish,
and I figured out the area of the whole thing. Concentric circles are
inscribed onto the dish. Also, the dish is divided into quarters by
two
perpendicular lines through the middle. I figured out the area of each
of
the six rings formed by the concentric circles, and the area of 1/4,
1/2,
and 3/4 of each of those rings, plus combinations of various rings and
various parts of other rings, and I put them all in a spread sheet.
Now
all I have to do is count the nematodes in a particular area, look at
this
chart, and multiply my counted total by the factor designated on the
list
for that area. Now I have the number of nematodes in the dish as
indicated by my sample of at least 100. Next, I have to correct for
soil
moisture, so I multiply this total by the factor I got above from the
soil
dry weight divided into 20 g. That give the number of that kind of
nematodes that would be in 100 g of soil if the soil were dry. (This
is
to standardize between all levels of soil moisture). But then, also, I
usually extract nematodes from 200 g of soil, so I have to divide by 2
in
there someplace to get the number that would be in 100 g (because 200/2
=
100.) So this is all just arithmetic, and I do it routinely on my
hand-held calculator.
The process for plant material is simpler: I just weigh the plant
material, put it under mist for a week, count the nematodes, and divide
be
the weight, and tell the sender how many nematodes per unit weight. We
use grams - metric is much simpler than English to use.
Speaking of metric versus English, when I first started this job, the
number of nematodes in soil were expressed as number/quart of soil.
This
is so dumb that there's not a word for it. The process at that time
was
to get nematodes from 20 g of soil and to multiply it by 20, and this
was
supposed to be the number per quart. As a math student, you can figure
out why this is illogical.
Descriptive statistics - that is, mean, standard deviation, standard
error, and things like that, are used in identifying nematode species.
You can tell what genus they are (usually) using the dissecting
microscope, but to figure out the species, you have to use the compound
scope. Some species characteristics are things like length and width
and
various ratios of lengths of body parts. There is a micrometer in the
scope eyepiece, and you count units in the micrometer, multiply by a
predetermined factor that gives you the number of microns in a unit at
that power, and that gives you the measurement in microns. I try to
measure several nematodes to determine the species. I then have a data
set for each measurement. I then determine the mean and standard error
(
for which you need the standard deviation) for comparison to published
descriptions. The standard error gives a rough estimate of how
variable
a data set is.
8. How do you use math in your job?
See answer for Question 7.
9. How do you use technology in your job?
1. Computers. I'm not
really good at using computers; I use them as tools rather than getting
excited about computers themselves, so I'm always several steps behind
everyone else. We use computers for planning experiments and analyzing
data; most of this is done by my boss. I use computers for everyday
things like writing letters to clients and e-mail. 2. The process of
getting nematodes out of soil is a density flotation method involving a
centrifuge. Soil is suspended in water and poured through various
sized
screens. A fraction of this soil is then suspended in sucrose syrup
and
centrifuged. The nematodes remain in the sugar solution, but the soil
particles are denser, and they sink to the bottom. I'm not sure
whether
or not this is technology. 3. The Nematodes in Oregon Agriculture Web
Site at http://mgd.nacse.org/hyperSQL/squiggles/ uses an innovative
computer language to enable the user to use a database easily. I
supplied
the information about nematodes for this site, but my computer frieds
did
all the computer stuff. Also on this site is information about how
many
plant-parasitic nematodes will damage some crops. Farmers can use this
information to decide whether or not to treat their crops for nematodes
after they get their results back from this lab. ----- most of the
nematology that we do is pretty low-tech. It involves a lot of looking
at
stuff through a dissecting microscope and counting worms.
I use computers for personal projects to write scientific
publications, to produce graphs, usually of number of organisms per
unit
weight or area over time, and to do spread sheets that provide the
numbers
to put into the graphs.
10. Do you have any fun hobbies we could in clued?
Quantitative bird
watching: I count and identify birds in a systematic way in the same
area
many times over years, and compare numbers between years, compare these
numbers to numbers from other areas or studies, and draw inferences
about
breeding, migration, and wintering. The birds I enjoy most are big ones
that don't hide, such as ducks and hawks. Native plants in my yard:
I
am attempting to grow native plants in my yard while getting rid of
Himalaya blackberry, English ivy, and wild garlic. I would like to
have
my yard simulate a native system. Moss identification: I collect
(with proper permits) mosses from particular areas and develop lists of
mosses and their relatives according to substrate (what they grow on).
I
also do the moss identifications for the Department of Botany and Plant
Pathology here at OSU.
11. Is there anything else you would like us to know?
Life is one
long
story problem, and it's fun.