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Chemical
Education International, Vol. 3, No. 1, AN-1, Received October 25,
2001
Systemic
Approach to Teaching and Learning Chemistry: SATLC in Egypt
A. F. M. Fahmy
Faculty of Science
Department of Chemistry
and
Science Education Center
Ain Shams University
Abbassia, Cairo, EGYPT
E-mail: [email protected]
J.
J. Lagowski
Department of Chemistry and Biochemistry
The University of Texas at Austin
Austin, TX 78712
E-mail: [email protected]
INTRODUCTION
In
1997, on the occasion of a visit by A. F. M. Fahmy to The University
of Texas at Austin, extensive discussions between A. F. M. Fahmy
and J. J. Lagowski laid the basis for the development of the Systemic
Approach to Teaching and Learning (SATL) Chemistry. Our interest
in developing the SATL strategy arose from the recognition of the
increasing globalization of a wide spectrum of human activities
such as economics, media, politics, and entertainment. We are not
interested here in a value judgment concerning globalization, rather
our position is that globalization is occurring at a rapid rate
and we have an obligation to our students to help them cope with
this phenomenon. Globalization implies a broader context when considering
human activities than a regional or a local perspective. Specifically,
our interest is in a vision of science education--that process by
which progress in science is transmitted to the appropriate cohort
of world citizens--that is sufficiently flexible to adapt to an
uncertain or, at best, an ill-defined future. That future, however,
ultimately must include an appreciation of the vital role that scientists
and chemists, in particular, have in human development. Thus, the
future of science education must reflect a flexibility to adapt
to rapidly changing world needs. It is our thesis that a systemic
view of science with regard to principles and their internal (to
science) interactions as well as the interactions with human needs
will best serve the future world society. Through the use of a systemic
approach, we believe it is possible to teach people in all areas
of human activity--economic, political, scientific, as well as ordinary
citizens--to exhibit a more global view of the core science relationships
and of the importance of science to such activities.
As
a start, we suggest the development of an educational process based
on the application of "systemics" (vide infra),
which we believe, will affect both teaching and learning. The use
of systemics, in our view, will help students begin to understand
interrelationships of concepts in a greater context, a point of
view that ultimately should prove beneficial to the future citizens
of a world that is becoming increasingly globalized. Moreover, if
students learn systemics in the context of learning chemistry, we
believe they will doubly benefit by learning chemistry and learning
to see all subjects in a greater context.
Concept
Mapping and Systemics. In retrospect, the key feature of systemics
(SATL) can be imagined as an extension of concept mapping. In the
early 1960's, when behaviorist theory prevailed among educational
psychologists, Ausubel published his theory of meaningful learning,
portions of which appeared in his book (1963) entitled "The
Psychology of Meaningful Verbal Learning" (1); a more
comprehensive view of his ideas was published later (2). Contemporary
assimilation theory stems from Ausubel's views of human learning
which incorporates cognitive, affective, and psychomotor elements
integrated to produce meaningful learning (as opposed to
rote learning). To Ausubel, meaningful learning is a process
in which new information is related to an existing relevant aspect
of an individual's knowledge structure and which, correspondingly,
must be the result of an overt action by the learner. Teachers can
encourage this choice by using tools such as concept maps (3).
It is postulated that continued learning of new information
relevant to information already understood (presumably) produces
constructive changes in neural cells that already are involved in
the storage of the associated knowledge units. In our view, an important
component in Ausubel's writing has been the distinction he emphasized
between the rote-meaningful learning continuum and the reception-discovery
continuum for instruction. The orthogonal relationship between these
two continua is illustrated in Figure 1.
Figure
1. Examples of instructional techniques displayed on the orthogonal
rote-meaningful learning continuum and the reception-discovery
continuum. (Adapted from Novack, J. D., "Learning, Creating,
and Using Knowledge," Laurence Erlbaum Associates, 1998,
Mohawk, NJ.)
According
to Ausubel, the essence of the meaningful learning process is that
symbolically expressed ideas are related to what the learner already
knows. Thus, in a sense, Ausubel's work also incorporates the elements
of contructivism. Meaningful learning presupposes that the learner
has a disposition to relate the new materials to his or her cognitive
structure and that the new material learned will be potentially
meaningful to him or her. In other words, it takes an overt act
by the learner to make learning meaningful. Concept mapping (3)
is a device that can be used to communicate to the learner as well
as providing a vehicle to help the learner with meaningful learning
tasks (vide infra). Of the types of meaningful learning that
Ausubel described--representational learning, propositional learning
and concept learning--the latter is of interest here. The acquisition
of subject matter primarily consists of concept learning. Concept
mapping (3) is a device that provides the basis of relating
new knowledge to previously assimilated knowledge in a systematic
way. Concept mapping also incorporates a strong element of constructivism,
in the sense that a student can build his/her understanding of new
concepts on those he/she has a deep familiarity. Concept maps have
been used as metacognitive tools to help teachers and learners to
improve both teaching and learning. Concept maps created by students
are an idiosyncratic representation of a domain specific knowledge
and provide teachers with information on what students know because
such maps can show the students initial concepts, how they are contextually
related, and how learners reorganize their cognitive structures
after a special teaching activity. It might be tempting to try to
use concept maps as the focus for the assessment of students' acquisition
of concepts, however, a number of observations on attempts to "score"
concept maps suggest that, currently, they are not good assessment
tools (4), mostly because there are many possible concept
maps that "correctly" show the relationships among a given
collection of concepts.
THE
SYSTEMIC APPROACH TO TEACHING AND LEARNING
We
introduce now the basic ideas of the systemic approach to teaching
and learning (SATL) as applied to chemistry. By "systemic"
we mean an arrangement of concepts or issues through interacting
systems in which all relationships between concepts and issues are
made clear, up front, to the learner using a concept map-like representation.
In contrast with the usual strategy (3) of concept mapping,
which involves establishing a hierarchy of concepts, our approach
strives to create a more-or-less "closed system of concepts"--a
concept cluster--(Figure 2b) which stresses the interrelationships
among concepts; Figure 2 also illustrates diagrammatically the difference
between a linear representation of concepts (2a) and our systemic
representation (2b).
Figure
2. Diagrammatic relationship between a linear approach (2.a.)
and the systemic approach (2.b.) in the presentation of concepts.
We
believe it is more difficult to obtain a global view of a collection
of linearly arranged concepts (2a) than with the systemic representation
(2b), which stresses all relationships among concepts. Further,
our use of the term "systemics" stresses recognition of
the system of concepts that form the closed cluster of concepts
under consideration. "Systemics" means in our hands, the
creation of closed-cluster concept maps for the purposes of helping
students learn; "systemics" is an instructor-oriented
tool and, hence, requires teacher and student materials to be created
about the closed-cluster concept map strategy.
In practice, the systemic approach allows the teacher to build up
sequentially a single concept map starting with prerequisite background
information required of the student before he/she starts on a systemic
approach to learning. Figure 3 shows this strategy
for developing the closed cluster concept map involving the five
concepts entitled E, F, X, Y, Z.
Figure
3. The evolution of a completed closed concept cluster from
a starting point exhibiting four unknown (to the student) relationships.
(Link to larger image)
The
instructor has in mind the concept structure shown in Figure 2a,
which he/she wants to develop into the closed cluster shown as Figure
2b. The prerequisites are simple bi-directional relationships between
the concepts. Thus, initially, there are four unknown (to the student)
relationships in the final cluster of concepts (Figure 3). The full
closed cluster concept map can be developed in four stages by sequentially
introducing the (initially) four unknown concepts. At each step,
another part of the final closed concept cluster is added and developed.
This process clearly illustrates the systemic constructivistic nature
of our SATL approach.
THE
APPLICATION OF SYSTEMICS TO CHEMISTRY INSTRUCTION
After
a preliminary study of the application of SATL techniques in secondary
schools in Cairo and in Giza, we embarked on a number of studies
to probe the extent (content material-subject matter) and level
of instruction that could be effectively expressed using such methods
and whether such methods helped students learn. A list of these
studies is given in Table I. All of these studies required the creation
of new student learning materials (as shown in Table 1), as well
as the corresponding teacher-oriented materials.
Table
1. A list of experiments conducted using the SATL strategy using
various aspects of the subject chemistry. The initial experiment
was conducted in 1998 in the secondary schools of the Cairo and
Giza school districts.
Student
Sample |
Title
of SATLC Material |
Duration
/ Date |
Data |
Pre-University
- Secondary School (2nd Grade) |
SATL-
Carboxylic acids and their derivatives (Unit) (5) |
(9
Lessons Two weeks) March 1998 |
Presented
at the
15th ICCE, Cairo, Egypt,
(August, 1998) |
University
Level
- Pre-Pharmacy.
- Second year,
Faculty of Science |
SATL-
Aliphatic Chemistry.
(Text book) (6) |
One
Semester Course: (16 Lects - 32hrs).
During the academic years (1998/ 1999-1999/2000-2000/2001) |
Presented
at the
16th ICCE, Budapest, Hungry,
(August, 2000) |
-
Third year,
Faculty of Science |
SATL-
Heterocyclic Chemistry.
(Text book) (7) |
(10
Lects. - 20 hrs).
During the academic years:
(1999/2000-2000/2001). |
Presented
at the
7th ISICHC, Alex., Egypt
(March, 2000) |
-
Second year,
Faculty of Science |
SATL-
Aromatic Chemistry
(Text book) (8) |
One
Semester Course: (16 Lects-32 hrs).
During academic year (2000-2001) |
In
preparation |
The
statistical analysis of student achievement results shows that the
students engaged with SATL materials and taught by teachers trained
in systemics achieve at significantly higher levels than those taught
by the standard linear methods.
More
SATL chemistry courses were produced by the Science Education Center
at Ain Shams University, which are still under experimentation in
different university settings (e.g., Inorganic Chemistry and Systemic
Organic Experiments). A description of these courses was presented
at the 1st Arab Conference on Systemic Approach in Teaching and
Learning, Organized by the Science Education Center at Ain Shams
University and the UNESCO regional office in Cairo, Egypt in February
2001.
SATL
COURSE EVALUATION
When
it is feasible, we attempt to evaluate the SATL courses that have
been created using student achievement as primary criterion for
success. Our evaluation strategy generally involves experimental
groups of students that use SATL materials taught by instructors
trained in SATL methods (Figure 2b) and an equivalent (as far as
background is concerned) control group of students taught by conventional
methods, which are often based on a linear strategy (Figure 2a).
Pre-college
courses. Our initial experiment probing the usefulness of the
SATL approach to learning chemistry was conducted at the pre-college
level in the Cairo and Giza school districts. Nine SATL-based lessons
in organic chemistry (9) taught over a two-week period were presented
to a total of 270 students in the Cairo and Giza school districts;
the achievement of these students was then compared with that of
159 students taught the same material using standard (linear) methods.
The details of a statistical summary of the results of achievement
tests on these experimental groups before and after the SATL treatment
and for the reference group before and after the same material was
presented in the conventional linear way is available for inspection
(5), but we address here only the overall results (Figures 4 and
5) for the sake of brevity. The results indicate that a greater
fraction of students exposed to the systemic techniques, the experimental
group, achieved at a higher level than did the control group (taught
by conventional linear techniques). These results are statistically
significant (5). The experimental (SATL) (Figure 4) and control
group (Figure 5) are separated into the individual schools in the
Cairo and Giza school districts.
Figure
4. Percent of students in the experimental classes who succeeded
(achieved at a 50% or higher level). The bars indicate a 50% or
greater achievement rate before and after the systemic intervention
period.
Figure
5. Students in the control classes who succeeded (achieved
at a 50% or higher level). The bars indicate a 50% or greater
achievement rate before and after the linear intervention.
All
of the students were tested before the experiment began to establish
the common background of these groups. The experimental group was
taught by SATL-trained teachers using SATL techniques with specially
created SATL materials, while the control group was taught using
the conventional (linear) approach.
Our
results from this pre-university experiment point to a number of
conclusions that stem from the qualitative data (5), from surveys
of teachers and students, and from anecdotal evidence.
- Implementing
the systemic approach for teaching and learning using one unit
of general chemistry within the course has no negative effects
on the ability of the students to continue their linear study
of the remainder of the course using the linear approach. (The
students in the experimental group resumed their studies using
the conventional linear approach.) Moreover, teacher feedback
indicated that the systemic approach seemed to be beneficial when
the students in the experimental group returned to learning using
the conventional linear approach.
- The
systemic approach can be introduced successfully in mid-course
at the secondary school level without problems for the students,
teachers, or schools, which addresses the question, "at which
stage can we begin to teach in a systemic way?"
- Teachers
from different experiences, professional levels, and ages can
be trained to teach by the systemic approach in a short period
of time with sufficient training. The training program in
systemics seems to impact teachers' performances during the experiment.
Thus, virtually any teacher with appropriate training and materials
can use SATL methods. The teacher training program requires the
development of special SATL materials.
- Anecdotal
evidence collected well after the experiment concluded suggests
that both teachers and learners retain their understanding of
SATL techniques and continue to use them.
Organic
chemistry: A study of the efficacy of systemic methods applied
to the first semester of a typical second year organic chemistry
course (16 lectures, 32 hours) at Zagazeg University was conducted
after the usual course materials on aliphatic chemistry were converted
to a systemic approach (6). We present now the details of the transformation
of the usual linear approach usually used to teach this subject
that involves separate chemical relationships between alkanes and
other related compounds (Figure 6) and the corresponding systemic
closed concept cluster that represents the systemic approach (Figure
7).
Figure
6. The classic linear relationship involving the chemistry
of the alkanes organized to begin to create a systemic diagram
of the corresponding chemistry.
This
systemic diagram in Figure 7 can be constructed from Figure 6 by
answering the following questions:
- What
are the systemic chemical relationships among methane, ethanol,
ethylene, and acetylene?
- What
are the systemic chemical relationships among all the compounds
in each of the following groups: ethane, ethylene, acetylene;
ethyl bromide, ethanol, acetic acid; succinic acid?
- What
are the systemic chemical relationships between ethyl bromide,
ethanol, and acetic acid?
Figure
7. The systemic diagram that represents some of the major
chemistries of alkanes.
The
answers to these questions are displayed in the systemic diagram
shown in Figure 7. Notice that, in Figure 7, some chemical relationships
are defined whereas others are undefined. The undefined chemical
relationships are collected in Table 2. These undefined relationships
are developed systematically. After a study of the synthesis and
reactions of alkenes we can modify the systemic diagram shown as
Figure 7 to accommodate other chemistries as shown in Figure 8.
Table
2. The following relationships are undefined in Figure 7.
The "number" (No.) is the number of the reaction on
the systemic diagram (Figure 7).
No.
|
Reactions
|
1
|
Ethylene
and acetylene |
2
|
Ethylene
and ethyl bromide |
3
|
Ethylene
and ethanol |
4
|
Pot.Succinate
and ethylene |
5
|
Methane
and acetylene |
6
|
Acetylene
and acetaldehyde |
7
|
Ethanol
and acetic acid |
8
|
Ethanol
and ethyl bromide |
9
|
Ethanol
and acetaldehyde |
10
|
Acetic
and acetaldehyde |
Figure
8. The SATL chemistry of alkanes (from Figure 7) as expanded
to include the alkenes. Note that reactions 5-12 (and the reagents
involved) are key issues.
Expanding
the chemistry of acetylene converts the systemic diagram in Figure
7 to that shown in Figure 9.
Figure
9. The SATL relationship between the hydrocarbons and derived
compounds.
In
a similar fashion, the systemic diagram shown in Figure 7 can accommodate
to the chemistries of ethyl bromide and ethanol yielding a new systemic
diagram.
The systemic diagrams developed in Figures 7 through 9 were used
as the basis for teaching organic chemistry course to experimental
group at Zagazeg University (Egypt). The experiment was conducted
within the Banha Faculty of Science, Department of Chemistry with
second year students. The experiment involved 41 students in the
control group, which was taught using the conventional (linear)
approach; 122 students formed the experimental group, which was
taught using SATL methods illustrated in the systemic diagrams shown
as Figures 7 through 9.
The success of the systemic approach to teaching organic chemistry
was established by using an experimental group, which was taught
systemically, and a control group, which was taught in the classical--linear--manner.
The equivalence of these groups was established by means of an examination
before the intervention. The examination for both groups
that was used to measure the achievement over the subject matter
incorporated both systemic- and linear-type questions. Figures
10 and 11 show the final data in terms of student achievement. The
bars in Figures 10 and 11 represent the percent of the students'
average scores on the examination components indicated (linear questions
or systemic questions). For each pair, the left-hand bar of each
pair represents the scores before the intervention and the right-hand
bar represents the scores after the intervention. Thus, the control
group (Figure 10) had an average score of 32.09% on linear-type
questions and an average score of 21.54% on systemic-type questions
before the intervention. The experimental group (Figure 11) had
an average score 31.30% on linear-type questions, and an average
score of 13.10% on systemic-type questions before the intervention.
These data indicate a marked difference between the control and
experimental groups. As might be expected, the control students
did not fare well on systemic questions, not having been exposed
to systemic reasoning. However, although the experimental students
started less able to answer systemic questions than the control
students (13.10% versus 21.54%), they did considerably better
after intervention (59.10% versus 22.73%) as might be expected.
The experimental group clearly achieved at a higher level as measured
by the total average score on the examination (62,10%
versus 27.08%). Finally, the use of systemics in teaching
these students appear to affect the ability of the experimental
group of students to answer linear questions (31.30% versus 65.60%).
Figure
10. Average scores for control groups before and after intervention.
See text for details.
Figure
11. Average scores for experimental group before and after
intervention. See text for details.
Heterocyclic
chemistry: A course on heterocyclic chemistry using the SATL
technique was organized and taught to 3rd year students at Ain Shams
University. A portion of the one-semester course (10 lectures, 20
hours) was taught to 53 students during the 1999-2000 academic year.
We
use heterocyclic chemistry to illustrate, again, how a subject can
be organized systemically. Figure 12 summarizes all the significant
reactions of furan, the model heterocyclic compound.
Figure
12. Some of the more important reactions of furan.
These
are the reactions that are generally discussed in a linear fashion
(Figure 2a) in the conventional teaching approach. However, these
reactions can be organized systemically as shown in Figure 13.
Figure
13. The systemic organization of the furan chemistry shown
in Figure 12. Notice the undefined species and reagents that are
necessary to complete the diagram. (Link
to larger image)
But
inspection of Figure 13 reveals seven unknown relations among the
furan compounds; these are listed in Table 3.
Table
3.
No. |
Chemical
relations |
1) |
2-Acetylfuran
to 2-ethylfuran (reduction-Wolff Kishner). |
2) |
2-Hydroxymethylfuran
to 2-methylfuran (reduction, H2/Ni-Co, D). |
3) |
Furfural
to 2-hydroxymethylfuran (reduction; NaBH4). |
4) |
2-Furoic
acid to 2-nitrofuran (nitration, HNO3). |
5) |
2-Furoic
acid to 2-bromofuran (bromination, Br2). |
6) |
2-Bromofuran,
to furan-2-sulphonic acid (sulphonation, H2SO4). |
7) |
2-Acetylfuran,
to furan-2-sulphonic acid (sulphonation, H2SO4). |
Figure
13 can be further refined to give Figure 14 by adding the unknown
chemical relations shown in Table 3.
Figure
14. The result of completing the undefined relation (Table
4) that appear in Figure 13. (Link
to larger image)
Before
the intervention, that is, teaching by systemics, the students in
this class all took an examination--we call the "zero point"
examination--which established their previous personal knowledge
of organic chemistry as obtained from previous courses. The data
summarized in Table 4 show that students taught systematically improved
their scores significantly after being taught using SATL techniques.
Table
4. Percentage increase in student scores.
|
Percent
increase in student scores
|
Before intervention
|
After intervention
|
Linear
questions |
37.32 %
|
49.53 %
|
Systemic
questions |
21.19%
|
90.29%
|
Total |
32.52%
|
69.1%
|
These
results are statistically significant at the 0.01 level. Statistical
details are available from AFMF (9).
SYSTEMICS
AND LABORATORY INSTRUCTION
In
this section, we discuss the use of systemics in laboratory instruction,
specifically, conducting experiments that reveal the "chemistry
of species" of interest (10). Applying Systemics to this phase
of laboratory instruction reveals the following advantages:
- Smaller
amounts of chemicals are used.
- Experiments
are done more rapidly.
- Students
easily acquire a working sense of the principles of green chemistry.
We
start our discussions with the classical laboratory-oriented subject
of qualitative analysis, which involves collecting chemical information
on the species of interest from which pool of information the identities
of the species of interest are deduced. Qualitative analysis involves
the application of linearly obtained chemical information to an
unknown solution in a linear way (Figure 15).
Figure
15. General linear strategy of qualitative analysis.
In
contrast to the generally linear approach of learning descriptive
chemistry of cations from a laboratory experience, a systemic method
has been developed that focuses attention on individual species
(Figure 16).
Figure
16. The systemic approach to the laboratory study of species
A+
The
reactions can be performed in a single test tube on a small sample
(=<0.5ml). This approach allows students to experience the colors
of chemical species, their solubility characteristics, and their
redox behavior. The "green chemistry" aspects of this
approach involve a very small amount of the cation-containing species,
which is contained in a very small volume. We now show the development
of a systemic closed-cluster cycle (Figure 17). This diagram shows
the qualitative investigation of Cr3+ species, the preparation of
Cr3+ compounds, and the interconversion of the species.
Figure
17. The systemic description of experiments defining the chemistry
of Cr3+.
Notice
that the formulas of chemical species of interest are expressed
in this diagram, but the reagents that bring about these conversions
are not given in the diagram in Figure 17. These
reagents are revealed experimentally in a series of reactions shown
in Figure 18a-d, which the students can do in the laboratory on
a small single sample of chromium-containing species.
Figure
18) a-d). The laboratory-based evolution of the chemistry
of chromium as performed by students. (Link
to larger image)
Thus,
the experiment diagrammed in Figure 18a reveals that hydroxide ion
(OH-) converts the green aqueous solution of Cr2(SO4)3 into the
grey-green precipitate of Cr(OH)3; the addition of hydrogen peroxide
converts the green precipitate into the soluble, yellow-colored
chromate ions (CrO42-); and so forth.
The
systemic technique can also be used to create an activity that develops
equation-writing skills (Figure 19).
Figure
19 (a-d). Examples of student activities using SATL techniques.
(Link to larger image)
We
suggest that the systemic diagrams shown in Figure 19 can be used
as a new assessment tool in chemistry (Systemic Assessment).
TRAINING
PROGRAMS
Over
and above the activities involving the creation and evaluation of
systemic materials, the Science Education Center (SEC) has been
engaged in the last two years in training programs using the systemic
approach. These programs included Chemistry Professors from several
Egyptian Universities where the training is focused on using the
systemic approach in teaching chemistry at the university level.
In addition, training programs were carried out for pre-college
teachers, which involved video conferences attended by about 8,000
school teachers as well as smaller groups in face-to-face training
sessions.
The Center is now engaged in preparing more of these programs at
all levels of instruction because of the success of the earlier
training programs.
SUMMARY
We
have attempted to describe the application of systemics to a variety
of chemistry-oriented courses starting with pre-college instruction
through advanced organic chemistry subjects as well as laboratory-oriented
instruction. In addition, we have presented the results of the evaluation
of this approach on student performance.
Literature
Cited
(1)
Ausubel, D. P., The Psychology of Meaningful Verbal Learning;
Grune & Stratton: New York, 1963.
(2)
Ausubel, D. P., Educational Psychology: A Cognitive View;
Holt, Reinhard and Winston: New York, 1968.
(3)
[a] Novak, J. D. and Gowin, D. B., Learning How to Learn;
Cambridge University Press: Cambridge, 1984.
[b] Novak, J. D., Learning, Creating and Using Knowledge;
Lawrence Erlbaum, Associates: Mahwak, New Jersey, 1998 and references
therein.
(4)
Stuart, H. A., Eur. J. Sci. Educ., 1985, 7,
73.
(5)
Fahmy, A.F.M., Lagowski, J.J.; Systemic Approach in Teaching and
Learning Carboxylic Acids and Their derivatives, http://www.salty2k.com/satlc.html
(6)
Fahmy, A.F.M., Lagowski, J.J.; "Systemic Approach in Teaching
and Learning Aliphatic Chemistry"; Modern Arab Establishment
for printing, publishing; Cairo, Egypt (2000).
(7)
Fahmy A. F. M., El-Hashash M., "Systemic Approach in Teaching
and Learning Heterocyclic Chemistry". Science Education Center,
Cairo, Egypt (1999).
(8)
Fahmy A. F. M., Hashem, A. I., and Kandil, N. G.; Systemic Approach
in Teaching and Learning Aromatic Chemistry. Science, Education
Center, Cairo, Egypt (2000).
(9)
Fahmy A. F. M., SATLC in Egypt; report to CTC. Meeting, Brisbane,
Australia (July 2001).
(10)
Fahmy, A. F. M.; Hamza M. S. A; Medien, H. A. A.; Hanna, W. G.;
and Lagowski; J. J.; Satellite conference of the WCC 2001; Brisbane,
Australia 1st July (2001): http://www.salty2k.com/satlc
Last
modified 21.05.02
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