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CANADIAN
SCIENCE
Executive
Editor:
Lydia
Dotto
Managing
Editor:
John
Holt
ISSN
07
12-488
Published
by:
Canadian
Science
News
Service,
Room
45,
University
College,
University
of
Toronto,
Toronto,
Ont.
M5S
1A1
(416)
595-7153
Canadian
Science
News
Service
acknowledges
a
grant
from
the
Science
Culture
Canada
Program
...
mi.n
i
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KEEP
f
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RIGHT
Kl.Qos
miiwi
ip
wjt'iMf'T
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'W
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"
Computer-video
system
lets
researchers
see
traffic
sign
as
seen
by
(left
to
right):
perfect
vision
up
close,
normal
20-year-old
vision
at
57
metres,
normal
70-year-old
vision
at
57
metres.
(Dr.
0.
Kline,
Univ.
or
Calgary)
Huge
flood
swept
ice
age
Canada?
By
Hugh
Westrup
During
the
last
ice
age.
North
America
may
have
been
inundated
by
an
enormous
flood
that
carried
enough
water
to
fill
Lake
Superior
seven
times
and
raised
the
level
of
the
ocean
by
nearly
a
foot,
says
a
Canadian
geographer.
Dr.
John
Shaw
of
Queen's
University
in
Kingston,
Ontario,
believes
that
the
Qoodwater
came
from
a
huge
reservoir
of
meltwater
that
had
aonirmiUted
under
the
Laurentide
ice
sheet,
the
giant
glacier
that
covered
much
of
North
America
during
the
last
ice
age.
The
reservoir
of
meltwater
was
Conned
when
geothermal
heat
from
the
earth
melted
the
underside
of
the
glacier.
Over
a
period
of
many
years,
the
reservoir
of
meltwater
grew
enormous.
Finally,
it
got
so
big
that
it
burst
out
from
under
the
glacier,
poured
over
the
land,
filled
river
valleys,
and
drained
into
the
ocean.
Evidence
for
the
flood
comes
from
an
area
in
northern
Saskatchewan
covered
with
dozens
of
small
elongated
hills,
called
drumlins,
all
of
which
point
in
the
same
direction
and
have
a
shape
mat
Shaw
describes
as
tall
and
narrow
at
one
end
and
low
and
broad
at
the
other.
The
drumlins
are
a
maximum
of
80
metres
high
and
can
be
one
to
two
kilometres
in
length,"
he
says.
Studying
an
aerial
photograph
of
the
drumlins,
Shaw
noticed
how
much
they
looked
like
pictures
he
had
seen
of
fhe
ocean
floor
after
it
has
been
eroded
by
turbulent
water.
He
wondered
if
it
was
possible
that
northern
Saskatchewan
was
once
covered
by
turbulent
water,
too.
"It
was
hard
to
tell
the
difference
between
the
drumlins
and
the
erosion
Not
exactly
what
tJ
WmmL,
mfffmi
LKjIJj
j,AJLLm
'jJLL
marks
on
the
ocean
bottom,"
he
says.
Shaw
thinks
the
drumlins
in
northern
Saskatchewan
were
formed
under
the
Laurentide
ice
sheet.
When
the
reservoir
of
meltwater
burst
out
from
under
the
ice
sheet,
it
carved
out
sizeable
cavities
on
the
underside
of
the
glacier.
As
the
flow
of
meltwater
subsided,
sand
and
gravel
filled
the
cavities
and
were
molded
into
hills.
When
the
glacier
retreated
at
the
end
of
the
ice
age,
the
hills
remained
as
drumlins.
Shaw
admits
that
his
idea
is
radical
and
that
many
scientists
don't
accept
it.
Dr.
David
Mickelson
of
the
University
of
Wisconsin
has
been
studying
drumlins
in
Wisconsin.
He
believes
that
the
drumlins
he
has
studied
were
formed
by
ice,
not
water.
Nevertheless,
other
evidence
has
turned
up
such
as
erosion
patterns
in
several
North
American
river
valleys
suggesting
that
at
least
one
and
maybe
as
many
as
20
floods
surged
over
North
America
in
prehistoric
times.
The
floods
seem
to
have
happened
between
10,000
and
14,000
years
ago,
the
same
era
in
which
the
last
ice
age
was
winding
down.
Though
no
similar-sized
floods
have
occurred
in
recent
times,
many
smaller
ones
have.
The
people
of
Iceland
even
have
a
word,
jokulhlaup,
to
describe
a
sudden
outpouring
of
water
from
under
a
glacier.
Shaw
says
that
many
ancient
myths
make
reference
to
a
primordial
deluge.
The
Maori
Indians
in
New
Zealand
tell
tales
of
a
sudden
rise
in
sea
level
long
ago,
while
the
Marxian
Indians
in
the
U.S.
have
a
story
about
a
big
flood
in
the
Missouri
River
valley.
Then,
too,
there's
the
well-known
Biblical
account
of
Noah
and
the
Ark,
he
says.
(Canadian
Science
Niwi)
it
looks
like.
tMsjsHnaBBiiHimNBHB
mmam
mmfSMStpmsusfza
Not
mountains
oa
the
moon,
but
colonies
of
Staphylococcus
bacteria
on
the
surface
of
heart
pacemaker.
A
Canadian
researcher
found
such
bacterial
colonies
coat
themselvas
with
cigar
fibres
that
help
them
stick
and
protect
them
from
astlbtotks,
etc.
(Photo:
Dr.
J.
W.
Costcrton,
Univ.
of
Calgary)
(Canadian
Science
News)
Researchers
study
problems
of
eyesight
in
aging
drivers
By
SaUy
Johnston
Two
Canadian
scientists
are
hoping
to
make
the
world
an
easier
place
to
see
especially
for
elderly
drivers.
Vision
experts
Dr.
Donald
Kline
of
Calgary
and
Dr.
Werner
Adrian
of
Waterloo,
Ontario
have
each
developed
a
computer
program
to
help
traffic
engineers
design
highway
signs
older
motorists
can
see
and
understand.
There
are
already
many
older
drivers
on
the
road,
and
their
numbers
are
likely
to
increase
as
the
population
ages,
says
Kline.
And
older
drivers,
on
a
per-mileage
basis,
are
involved
in
a
disproportionate
number
of
accidents
and
traffic
violations,
he
adds.
Kline's
program
uses
video
images
to
let
any
viewer
see
a
particular
scene
the
way
an
elderly
person
with
aging
vision
does;
Adrian's
produces
numerical
measurements
of
how
well
such
a
person
could
see
a
particular
sign.
Eyes
naturally
deteriorate
with
age,
which
means
the
elderly
have
problems
seeing,
especially
in
glare
or
dim
lighting.
"Highway
lighting
and
highway
signs
are
based
on
what
is
judged
to
be
adequate
for
young
eyes,"
says
Adrian,
professor
of
optometry
at
the
University
of
Waterloo.
"But
older
eyes
don't
function
quite
as
well,
especially
after
dark,"
he
points
out.
"Why
not
base
design
standards
on
the
visual
capability
of
older
eyes?
That
way,
the
older
driver
will
be
safe
and
the
younger
ones
will
have
an
even
greater
margin
of
safety."
Better
street
lighting,
larger
lettering
on
signs
and
greater
use
of
symbols
rather
man
text
on
signs
Overcrowding
is
weed
control
Ontario
agricultural
scientists
are
waging
a
war
against
weeds
by
crowding
them
out
of
the
fields
with
crops.
The
researchers
believe
the
technique
could
help
reduce
the
need
for
herbicides,
in
line
with
the
province's
goal
to
halve
the
use
of
the
farm
chemicals
within
the
next
10
years.
In
experiments
at
the
University
of
Guelph,
the
scientists
significantly
reduced
weed
growth
in
a
field
of
white
beans
by
increasing
the
number
of
plants
per
hectare
by
SO
per
cent
and
reducing
the
space
between
rows.
As
a
result,
there
was
almost
no
room
for
weeds
to
grow.
The
few
that
tried
to
squeeze
through
died
or
were
weakened
due
to
lack
of
sunlight
in
SVIore
teens
say
no
to
Ontario
high
school
students
report
that
they're
saying
"no"
to
drugs,
cigarettes
and
alcohol
more
often
than
they
did
10
years
ago,
according
to
the
latest
survey
by
the
Addiction
Research
Foundation.
The
survey
of
about
4,000
students,
aged
12
to
19
years,
is
the
seventh
in
a
series.
Surveys
are
conducted
in
alternate
years.
The
survey
found
that
23.3
per
cent
reported
using
tobacco
in
1989,
compared
with
34.7
per
cent
in
1979.
Two-thirds
of
students
reported
using
alcohol
compared
with
76.3
per
cent
in
1977.
Reported
use
of
illegal
drugs
is
also
down
significantly
since
the
late
1970s.
Fourteen
per
cent
of
students
admitted
using
cannabis
in
1989,
would
improve
road
safety
for
the
elderly,
says
Kline,
director
of
the
vision
and
aging
laboratory
at
the
University
of
Calgary.
As
people
grow
older
the
lens
and
cornea
in
the
eyes
become
yellowish
and
opaque,
so
less
light
gets
to
the
retina,
the
part
of
the
eye
which
receives
the'image,
Adrian
explains.
A
60-year-old
eye
receives
less
than
half
the
light
received
by
a
20-year-old
eye,
he
says.
Also,
the
light
that
does
travel
to
the
retina
is
more
likely
to
'stray',
so
it
appears
more
blotchy
to
an
older
person
than
to
a
younger
one.
The
result
can
be
like
looking
into
the
high-beam
headlights
on
an
oncoming
car.
The
elderly
also
have
problems
seeing
moving
objects,
things
on
either
side
and
objects
in
shade
or
low
light.
Where
a
young
person
sees
a
bus
looming
faintly
out
of
the
fog,
it
may
be
invisible
to
an
older
person.
When
Kline
surveyed
elderly
drivers,
they
reported
that
they
have
difficulty
judging
the
speed
of
their
vehicles,
that
other
vehicles
move
too
quickly,
that
they
are
often
surprised
by
merging
vehicles
and
that
other
vehicles
arrive
in
their
peripheral
field
of
vision
unexpectedly
These
problems
probably
contribute
to
older
drivers'
disproportionately
high
rate,
on
a
miles-driven
basis,
of
accidents
and
traffic
tickets.
The
three
most
frequent
types
of
accidents
in
old
age
are
failure
to
yield
right-of-way,
failure
to
heed
signs,
and
failure
to
turn
appropriately
-which
seems
to
correspond
to
the
types
of
vision
problems
they
report,"
the
shade
of
the
densely-planted
crop.
These
natural
weed-control
methods
allowed
the
researchers
to
apply
half
the
recommended
amount
of
herbicide
without
affecting
the
crops'
yield.
Similar
tests
were
conducted
without
herbicides
but
led
to
lower
crop
yields
because
some
weeds
still
grew.
The
researchers
feel,
however,
that
some
consumers
might
be
prepared
to
pay
more
for
chemical-free
produce;
the
higher
price
would
help
farmers
offset
lower
yields.
The
intensive
planting
of
the
crops
should
not
exhaust
the
soil
as
long
as
appropriate
crop
rotation
and
soil
management
techniques
are
used,
the
researchers
say.
In
a
separate
study
at
Guelph,
legions
of
dead
crops
are
also
proving
down
from
almost
one-third
in
1979,
and
2.7
per
cent
reported
using
cocaine
in
1989,
compared
with
5.1
per
cent
a
decade
earlier.
Also,
more
students
reported
using
no
drugs
at
all,
including
alcohol
and
tobacco
-
29.2
per
cent
in
1989
compared
with
17.4
per
cent
in
1979.
For
the
first
time
the
survey
asked
about
use
of
injection
and
performance-enhancing
drugs.
Just
over
one
per
cent
reported
using
steroids
at
least
once
and
0.2
per
cent
said
they
were
injection
drug
users
who
share
needles.
ARF
scientist
Dr.
Reginald
Smart
says
the
reported
drop
in
drug
use
is
encouraging
but
leaves
"no
room
for
complacency.
Even
low
percentages
of
drug
use
represent
a
large
number
says
Kline.
Kline
has
developed
a
computer
image-processing
program
that
engineers,
designers,
driver
trainers
and
educators
can
use
to
'see',
on
a
video
screen,
signs
and
markers
u
they
would
be
seen
by
an
older
person.
Kline
takes
a
video
picture
of,
for
instance,
a
KEEP
RIOHT
sign.
A
digitized
version
of
the
picture
is
passed
through
an
electronic
'filter'
in
the
computer
which
processes
the
image
in
exactly
the
same
way
as
the
eyes
of
the
average
80-year-old.
The
resulting
picture
is
displayed
on
a
video
screen.
The
vision
filter
technique
can
be
set
for
any
age,
so
Kline
can
view
the
world
through
the
eyes
of
anyone
from
18
to
100
years
old.
In
Waterloo,
Adrian
has
produced
a
computer
program
that
crunches
numbers
instead
of
pictures.
But
it
does
the
same
job
as
Kline's
system
for
example,
shows
how
well
an
older
driver
with
normal
eyesight
can
read
a
sign
100
metres
away
if
approaching
at
40
kilometres
an
hour.
The
result
is
given
in
the
form
of
the
answer
to
a
mathematical
equation.
"Highway
designers
need
to
know
what
basic
visual
functions
are
possible,
depending
on
factors
such
as
the
size
of
objects
and
the
illumination
levels,
for
all
ages.
We
now
have
a
computer
model
that
can
give
them
that,"
says
Adrian.
Both
scientists
say
their
computer
programs
have
many
other
applications,
such
as
in
the
design
of
signs
at
airports,
train
stations,
hospitals
and
nursing
homes.
(Canadian
Science
newt)
effective
in
the
battle
against
weeds.
Scientists
planted
a
field
with
rows
of
winter
varieties
of
wheat,
rye
and
triticale
(a
ryewheat
hybrid).
The
following
spring,
the
crops
were
mown
and
left
lying
on
the
ground
between
the
rows
as
mulch
(protective
covering).
Soybeans
were
then
planted
where
the
grain
had
stood.
Besides
the
usual
benefits
of
preserving
soil
moisture
and
protecting
against
soil
erosion,
the
mulch
shaded
the
ground
and
prevented
weed
seeds
from
sprouting.
Also
the
soybeans
thrived,
faring
better
than
a
nearby
control
group
without
mulch.
(Canadian
Science
News)
drugs
of
students."
'If
we
look
at
the
entire
(Canadian)
student
population
from
grade
seven
to
13,
one
per
cent
or
8,800
have
used
crack,
0.4
per
cent
or
3,500
use
cannabis
daily
and
0.7
per
cent
or
6,180
sought
medical
help
for
their
drug
use,"
he
says.
The
researchers
feel
the
survey's
result
-
that
drug
use
among
students
is
decreasing
is
reliable
even
though
it
is
based
on
students'
self-reporting,
Smart
says.
For
one
thing,
the
survey
contained
trick
'control'
questions
to
trip
up
falsifiers.
For
another
thing,
other
studies
have
shown
that
adolescents
tend
if
anything
to
exaggerate
their
use
of
drugs,
he
adds.
(Canadian
Selene
News)