511
e .
: ,
e
e
.
a . , a .
,
. . , . y
:
s
y
e
s
50 100
. a
y
s
200 . a
. ,
. a
1.5
, a ,
.
.
, 1
.
4 a a
.
, ;
,
. .
10 ,
a
.
, a . ,
. c
2:
,
y
s
5
s
s
Downloaded by: University of British Columbia. Copyrighted material.
. ,
512
1992; 24
. .
a a
a a
. a
. ,
,
, .
, . a a
. e 3:
a
a
e e
.
.
a
.
,
: .
.
, a 1.44
a
.
,
a
,
a
.
,
. . .
,
, ,
,
a
386 .
300 a
15
20
5
a
20
, a
a
.
, a .
a a
, a
15
.
20
: .
. .
,
, a
.
, .
e
e
e
, a
a ,
.
,
,
,
a
.
.
a
,
,
a
.
,
a .
a
. ,
. ,
. .
a
,
a .
, ,
.
. a
.
1.44 $ 1 $8.
4
a 5
Downloaded by: University of British Columbia. Copyrighted material.
, .
513
1992; 24 .
, 15
a 30
a
5 $4,500 a
. .
$6.92
. a
. a
5
2
5
80 $500
a
. 266
a a
. .
1
$2,000. a
e
e
. 1,00
. $90.
a
a
, .
a .
:
,
,
,
.
a
.
a
, .
a a
a
3
,
.
a
a
.
a
,
a
, ,
. a
a
.
,
.
. a
, a
a ,
180
,
. 2
,
300
2,000
,
.
,
$300. a a 650
. .
, .
a
5
. 6
$4,000
. ,
$5,500. .
. a a
: ,
,
a ,
,
.
a ,
a
.
a ,
.
,
,
,
. .
.
a . $ 250
$ .38
a
.
a
e1 s
s 5
c y
1.44 650 300x2
5.60 6.92 0.38
4 266 2000
0 0 250
2 6
5
Downloaded by: University of British Columbia. Copyrighted material.
2
514
24
e ,
e
e 5:
.
e
.
.
a ,
a .
,
.
,
a
a .
.
, ,
a . .
a a
, a
a
.
a a
, 1
a
. a
. a
.
a .
,
, ,
a
a
.
.
a .
. ,
.
a
, .
, a
.
: a
.
,
,
.
, a .
a a . , a a
. .
a
. .
, ,
, a
, . .
, ,
Downloaded by: University of British Columbia. Copyrighted material.
e 4: a
.
: e e
, ,
, 4
Downloaded by: University of British Columbia. Copyrighted material.
1992: 24 515
. .
,
,
. e