Seminar: 19F-NMR Studies of Modified Insulins. Chemistry Department, CSU Fresno (1974).
Seminar: 19F-NMR Studies of Modified Insulins. Chemistry Department, CSU Long Beach (1975).
Lecture: Microtubules and Cell Architecture. Mt. San Jacinto College (1976).
Seminar: 19F-NMR Studies of Modified Insulins. Chemistry Department, HSU (1977).
Lecture: On the Origin of Life. Biology Department, HSU (1979).
Workshop: taught carpentry to a Girl Scout Junior Patrol for a troop badge (six girls, 1979).
Demonstration: Chemistry Magic Show for Mr. McClean's fifth grade class at Sunset School, Arcata (approx. one hour, F 1979).
Lecture: Interstellar Chemistry. HSU Physics Department (Dec. 1979).
Lecture: Interstellar Molecules and Life from Outer Space? Astronomers of Humboldt (Nov. 1979).
Lecture/Demonstration: Talked about turtles and their adaptations using a live desert tortoise and turtle to Mrs. Paita's first grade class (approx. one hour, Sp 1980)
Lecture/Demonstration: Microscopes and microscopy (brightfield, polarizing and diseecting) for Mr. McClean's fifth grade class at Sunset School, Arcata (approx. two hours, Sp 1980).
Workshop: organized and ran a Summer Science Club for Fifth graders. Topic meetings included microscopes, chemical reactions, magnets and electricity, a nature walk, etc, (4–6 children/meeting, Su 1980).
Lecture/Demonstrations: Chemical Magic Show and Talk. Mr. Cherney's 6th grade classfrom Pacific Union School (held at HSU Chem. Dept.; 03/24/81).
Lecture: Molecular Chemistry in Interstellar Space. HSU Physics Department (1981).
Lecture: The Origin of Planetary Systems. Astronomers of Humboldt (1981).
Discussion panel member, Growth and Change in Adult Life. HSU (1981).
Demonstration/talk: Chemical Magic Show. Arcata Cub Scouts. (04/29/82).
Lecture/Demonstration: Food and Chemistry—What I do as a Biochemist. Mr. Cherney's 7th grade class, Pacific Union School (03/25/82)
Lecture series: In the Beginning... From Atoms to Adam. A survey of modern speculations concerning the origins and distribution of matter and life in the Universe. One week lecture series for Elderhostel at HSU (July 11-17, 1982).
Lecture series: Chemistry - Key to the Universe. A survey of modern chemistry illustrated with demonstrations. One week lecture series for Elderhostel at HSU (July 18-24, 1982).
Lecture: The Development of the Clock and the Concept of Time in the Middle Ages.Society of Creative Anachromism, HSU & HSU History Club (1984).
Lecture/Discussion: The Nature and Compatibility of Science and Religion Using the Creationist Debate as an Example. Methodist Youth Fellowship of Arcata Methodist Church, (1984).
Lecture series: In the Beginning... From Atoms to Adam. See above - updated repeat of 1982 series. One week lecture series for Elderhostel at HSU (August 4-10, 1985)
Introductory for Zymed Workshop. FASEB85. Anaheim CA (04/23/85).
Lecture: Immunological Methods in Biochemistry. Chemistry Department, HSU, (Based on my consulting with Zymed, 1985).
Workshop leader, Modern Analytical Chemical Instrumentation at HSU: Theory and Operation. First day of one-week Summer Chemistry for Teachers workshop presented at HSU (August 1985). Lectures and demostrations included theory and applicaions of absorption spectroscopy with demonstrations of UV-Vis and Atomic Absorption spectrometers; Theory and application of Capillary GLC and HPLC with demonstrations of HPLC reversed phase analysis and capillary GC-MSD.
Discussion panel member, Darwin Centenary Symposia-Darwin, for Better or Worse. HSU (1985).
Discussion panel member & lecturer, Shark Symposium. HSU (1985).
Lecture: Current Gas Chromatography and GC/MS - Concepts and Clinical Applications. California Association of Medical Laboratory Technologists, St. Joseph's Hospital, Eureka, CA (1985).
Lecture: The first one million years of the universe. Redwood Empire Chapter, ABWA (1985).
Lecture/Discussion: Why Scientists are Male. Presentation to HSU ARCH (adult re-entrygroup, Sp. 1987).
Guest Expert. Dioxin. KHSU Tuesday Night Talk (11/18/87)
Lecture/Discussion. How the Brain Works. Presentation to HSU I.E.L.I (International English Language Institute, Sp. 1987).
Lecture series: Alchemists and Astrologers - the origins and early history of science and technology. One week lecture series for Elderhostel at HSU exploring the origins and development of science and technology illustrated with ancient scientific instruments. (June 1988).
Lecture/Discussion: Enivironmental Toxicology. Presentation sponsored by CCAT and HSU AS (2.5 hr, November 15, 1988)
Lecture. Visualization of the Abstract in Chemistry: Atomic Orbitals. Seminar presented to the Chemistry Department and the campus community, Humboldt State University, (April 20, 1990).
Lecture: Science in the Middle Ages (1200-1500) (SCA Barony of Aleshia Arts and Sciences Tourney, 1997). [http//www.Humboldt.edu/~rap1/public_html/EarlySciInstSite/Workshops/MedSciWrkshp.htm]
Lecture: Science in the Middle Ages (1200-1500) (SCA West Kingdom Arts and Sciences Tourney, 1997). [http//www.Humboldt.edu/~rap1/public_html/EarlySciInstSite/Workshops/MedSciWrkshp.htm]
Lecture: The Development of the Clock and the Concept of Time in the Middle Ages. (SCA West Kingdom Arts and Sciences Tourney, 1997). [http//www.Humboldt.edu/~rap1/public_html/EarlySciInstSite/Workshops/MedSciWrkshp.htm]
Workshop for adolescent girls. Chemists Have the Solutions (Expanding Your Horizons, HSU: Sp1997).
Workshop for Teachers and Parents. Home Work (Expanding Your Horizons, HSU: Sp1997).
Presenter, “Science Mall” See an Atom, Build a Molecule (Expanding Your Horizons, HSU: Sp1997).
Lecture: Astronomy, Calendars, and Time in the Middle Ages. (SCA West Kingdom Arts and Sciences Tourney, 1998). [http//www.Humboldt.edu/~rap1/public_html/EarlySciInstSite/Workshops/MedSciWrkshp.htm]
Workshop: Medieval Scientific and Philosophical Instruments. Instruction on the fabrication and use of simple replica instruments. (SCA West kingdom Arts and Sciences Tourney, 1998). [http//www.Humboldt.edu/~rap1/public_html/EarlySciInstSite/Workshops/MedSciWrkshp.htm]
Workshop for adolescent girls. Chemistry has the Solutions (Expanding Your Horizons, HSU: Sp1999).
Workshop for Teachers and Parents. Home Work (Expanding Your Horizons, HSU: Sp1999).
Lecture: Practical Medieval Astronomy. (SCA West Kingdom Arts and Sciences Tourney, 1999).
Workshop: Medieval Scientific and Philosophical Instruments. Instruction on the fabrication and use of simple replica instruments. (SCA West Kingdom Arts and Sciences Tourney, 1999). [http//www.Humboldt.edu/~rap1/public_html/EarlySciInstSite/Workshops/MedSciWrkshp.htm]
Workshop: Medieval Scientific and Philosophical Instruments. Instruction on the fabrication and use of simple replica instruments. (SCA Barony of Aleshia Arts and Sciences Tourney, 2000). [http//www.Humboldt.edu/~rap1/public_html/EarlySciInstSite/Workshops/MedSciWrkshp.htm]
Workshop: Medieval Astronomical Timekeeping Instruments. Instruction on the fabrication and use of simple replica instruments. (SCA Barony of Aleshia Arts and Sciences Tourney, 2001). [http//www.Humboldt.edu/~rap1/public_html/EarlySciInstSite/Workshops/MedSciWrkshp.htm]
Initiator and Co-Coordinator (with Spring Garrett) of Evolution! Lectures and Activities in Conjunction the the PBS Mini-Series sponsored by the HSU Natural History Museum and the HSU College of Natural Resources and Sciences in conjunction with the PBS mini-series, Evolution and KEET TV (20 September–5 October 2001).
Lecture: Molecules, Evolution & Medicine. One-hour lecture sponsored by HSU Natural History Museum and HSU College of Natural Resources and Sciences in conjunction with the PBS mini-series, Evolution and KEET TV (20 September 2001).
Presentation for high scholool teachers at the HSU Natural History Museum on Using the HSU NHM for teaching evolution. (19 October 2001).
Workshop for Teachers and Parents. Home Work (Expanding Your Horizons, HSU: Sp 2001).
Keynote speaker for the opening ceremonies of the Precambrian exhibit at the HSU Natural History Museum. (Fall 2002)
Facilitator/scholar for The Research Revolution: Science and the Shaping of Modern Life a six week video/discussion series held at the Eureka Public Library under the sponsorship of National Video Resources, the HSU Library and the Eureka Public Library (March 26-April 30, 2003).
Presenter/Workshop leader, Rough Science Activity Day, HSU Natural History Museum (February 22, 2003).
Lecture: The Earth's First Four Billion Years: From the Solar Nebula to the Cambrian Explosion. One hour talk for Humboldt Preview, Humboldt State University, Arcata, CA. (Spring 2003).
Workshop for Teachers and Parents. Home Work (Expanding Your Horizons, HSU: Sp 2003).
Displayed and demonstrated/explained Medieval scientific instruments/science at St. Bernard's Catholic School 1st annual Medieval Festival (9 June 2003).
Lecture: Precambrian Life. One hour talk for HSU Natural History Museum. (26 February 2004).
Presenter: 8th Annual CalSoap College and Career Fair, HSU (9 March 2004).
Lecture: Earth's First Four Billion Years - From the Solar Nebula to the Cambrian Explosion. One hour talk for Humboldt Preview (17 April 2004).
Keynote Address: Demonstrations, Fun with Science, and Science Education California Math Council of the far North Annual Conference, "Keeping the Fun in Math and Science", Arcata CA (23 October 2004).
Lecture: The Origin of the Solar System Public talk sponsored by HSU Natural History Museum and HSU College of Natural Resources and Sciences in conjunction with the PBS/Nova "Origins" series. (HSU 23 September 2004).
Lecture: Life and its Beginning Public talk sponsored by HSU Natural History Museum and HSU College of Natural Resources and Sciences in conjunction with the PBS/Nova "Origins" series. (HSU 30 September 2004).
Lecture: Geochemistry and Evolution in the Proterozoic invited talk for the HSU Geology Department Colloquium Speakers Series (HSU 15 November 2004).
Presenter/Workshop leader, Meet the Scientists Discovery Day, HSU Natural History Museum (19 February 2005).
Presenter: “Chemistry Magic Show”, Science Mall, Expanding Your Horizons, HSU (Sp 2005).
Lecture: Geochemistry and Evolution in the Precambrian. One hour talk for Humboldt Preview (updated and added PowerPoint presentation - 9 April 2005).
Workshop: Chemistry Institute Lead Instructor, Northcoast Mathematics and Science Initiative (NMSI). One-week intensive workshop on the foundations of inorganic chemistry for high school and upper grade school teachers (25 students, June 20–24, 2005 HSU).
Presenter: “Spiders”-10th annual Natural History Halloween. Two-hour interactive presentation to museum visitors. HSU Natural History Museum (28 October 2005).
Presenter: “Chemistry Magic Show”, Discovery Museum, Eureka, CA (29 October 2005).
Presenter, with Jess Vickery: "An Explosive Night of Science", 4th Annual Science Night Extranvaganza kickoff for the 2006 Doris Niles Science Fair, Humboldt County Office of Education. Van Duzer auditorium, Humboldt State University. One-hour interactive chemistry demonstation show for approximately 300 3rd-12th students and parents (11 January 2006).
Session Organizer: "The Art, Science, and Technology of Medieval Travel V: Medieval Navigational Instruments," 41st International Congress on Medieval Studies, Western Michigan University, Kalamazoo MI (May 5, 2006).
Presenter/Demonstrator with Sara Schechner (Harvard University): "Medieval Navigation Instruments, A reception with demonstrations." AVISTA reception at the 41st International Congress on Medieval Studies, Western Michigan University, Kalamazoo MI (May 5, 2006).
Presenter: “Chemistry Magic Show”, Discovery Museum Carnival, Eureka, CA (2 June 2006).
Co-Presenter (with Eric Van Duzer), “5th Annual Science Night Extravaganza” HSU Van Duzer Theater. (11 January 2007).
Science Mall presenter and mentor for student (Sara Downey) co-presenter (“Chemistry Magic Show”), Expanding Your Horizons. HSU (March 24, 2007)
Lecture: “The Instruments and Intentions of Alexander von Humboldt: the South American Expedition of 1799-1804.” Presentation as part (second half) of Mathematics Colloqium, (October 18, 2007).
Co-Presenter (with Richard Stepp), “6th Annual Science Night Extravaganza” HSU Van Duzer Theater. (16 January 2008; 1 hr presentation, 5 hr prep and cleanup).
Member, panel on Science and the Clash of Ideas, for the 2008 Religion and Humanism forum at Humboldt State University (1 March 2008; 1 hr panel discussion, 5 hr forum attendance and 5 hr preparation).
Lecture: “Early navigational instruments and the determination of latitude”; HSU Mathematics Colloquium invited speaker; (10 April 2008; 1 hr, 3 hr prep)
Volunteer, "Big Bug Discovery Day." Interactive presentation/demonstrations to museum visitors on beetles and bugs. HSU Natural History Museum (4 October 2008; 5 hr activity; 1 hr prep).
Volunteer, HSU Natural History Museum New Exhibits Reception. Interpreted new Permian exhibit case for visitors. HSU Natural History Museum (9 October 2008; 1.5 hr activity).
Lecture: "Instruments of Medieval Astronomy"; HSU Mathematics Colloquium invited speaker; (23 October 2008; 1 hr, 10 hr prep)
Presenter: “Chemistry Magic Show”, HSU Educational Talent Search, HSU campus, Arcata, CA (21November 2009; <1 hr, 2 hr prep/cleanup)
Lecture: "The Problem of the Longitude and the Invention of the Sextant." HSU Mathematics Colloquium invited speaker; (Spring 2010; 1 hr, 20 hr prep)
Presenter and mentor for student (Essene Waters) co-presenter : “Chemistry Magic Show”, Science Night at Freshwater, Freshwater School, Eureka, CA (1 April 2011; 2 hr,4 hr prep/cleanup).
Instructor/Presenter: "Fossils and the Evolution of Life Through Time", six week course for Osher Lifelong Learning Institute (OLLI), Humboldt State University Natural History Museum (3/28/12 - 5/2/12; six two hour presentations @ 10–20 hr prep/cleanup each).
Guest Lecturer: "Walk Through Time Exhibit", one-hour guided tour/lecture-discussion of Walk Through Time display cases at HSU NHM for Science, Media and Communication Institute: Ocean Sciences (5/22/2012, 3 hr prep).
Instructor/Presenter with H.E. Harvey II: "Longitude & the Invention of Instruments for Navigation", three week course for Osher Lifelong Learning Institute (OLLI), Humboldt Bay Aquatic Center (9/5/2012 - 9/19/2012; three two hour presentations @ 10–20 hr prep/cleanup each).
Instructor/Presenter: "Fossils and the Evolution of Life Through Time", six week course for Osher Lifelong Learning Institute (OLLI), Humboldt State University Natural History Museum (10/20/2012 - 10/1/2012; six two hour presentations @ 3–6 hr prep/cleanup each).
Volunteer, "Humboldt State's 100th Birthday Festival" presentation/Q&A (fossil and animal specimens) at HSU Natural History Museum tables (25 August 2013; 3 hr activity; 1 hr prep).
Instructor/Presenter: "Longitude & the Invention of Instruments for Navigation", three day course for Osher Lifelong Learning Institute (OLLI), Humboldt Bay Aquatic Center (10/1/2013 - 10/8/2013; three two hour presentations @ 4–6 hr prep/cleanup each).
Instructor/Presenter: "Alexander von Humboldt’s Latin American Expedition (1799–1804): Instruments, Geography & Botany", one day course for Osher Lifelong Learning Institute (OLLI) celebrating the namesake of HSU as part of HSU's Centennial celabration, Humboldt Bay Aquatic Center (10/1/2013 - 10/8/2013; one two hour presentation & 8–10 hr prep/cleanup).
Presention/Tour. "Centennial Celebration 1913–2013, College of Natural Resources & Sciences—Scientific Instrument Museum" Introduction to the museum's special Centennial display on the Instruments and Observations of Alexander von Humboldt, namesake for HSU, and HSU's history of sceince education as documented in the Robert A. Paselk Scientific Instrument Museum. One hour presentation followed by 30 min tour of museum displays in Library; HSU Library Fishbowl, Room 209 & museum on Library 2nd floor. (3–4 hr preparation, 10/15/2013).
Instructor/Presenter: "Longitude & the Invention of Instruments for Navigation", three day course for Osher Lifelong Learning Institute (OLLI), Humboldt Bay Aquatic Center ( Updated presentation from 2013 with materials from visit to the Longitude Act Tercentenial exhibit at RM Greenwich, Ships, Clocks and Stars: the Quest for Longitude, and discussion with Richard Dunn (August/14) and reading the the accompanying book by Dunn and Higgittt; three two hour presentations @ 1 hr cleanup each; 10/7/2014 - 10/14/2014).
Instructor/Presenter: "Fossils and the Evolution of Life Through Time", three week course for Osher Lifelong Learning Institute (OLLI), Humboldt State University Natural History Museum (Repeat of 2013 OLLI course but at new NHM; five two hour presentations @ 3–4 hr prep/cleanup each; 4/7/2015 - 4/21/2015).
Presenter. "Early Scientific Instruments in Art and Practice." one hour Power Point lecture with demonstrations based on recent museum display ("Replicas and Restorations of Early Instruments by Richard A. Paselk". HSU Library Fishbowl, Room 209. (2–3 hr preparation, one hr set-up/cleanup; 8/12/2015).
Presenter. "Cal Poly Humboldt Scientific Instrument Museum: Balances and Standards; the new SI mass definition (2019)". 2024 ISASC Convention, Walnut Creek, CA (45 min talk, 5-8 hr preparation; 5/04/2024).
Presenter/Display designer. "Scientific Instruments from the 1950's" MOSAC Mixer: 50's Night; SMUD Museum of Science and Curiosity, Sacramento CA (8–12 hr preperation, 11 instruments with labels/short explanations. Visitors invited to try out microscopes, slide rules, refractometer and polarimeter, including determining unknown glucose concentration in 'urine' and sucrose samples via polarimeter; 8/1/2024, 6–10 pm).
(Over 700 photos posted on HSU websites; over 100 photos are posted on reviewed external web-sites.)
Blunt-nosed leopard lizard. PG&E Midway Substation Maintenance and Operations Guideline For Protecting Rare Plants and Animals (internal training brochure). Pacific Gas and Electric Company (2000).
Rugose coral. Scientific American. 285, 43 (November 2001).
Phytosaur teeth. Scientific American. 285, 43 (November 2001).
Hatchling turtles and eggs. L’Odyssée de le science et de la technologie (activity book for Grade 6 Quebec students). Le Editions CEC inc. Anjou, Quebec. 33 (2002 & 2004).
Mettler single-pan substitution balance. Luminaries of the Chemical Sciences (supplement to Today’s Chemist at Work.) American Chemical Society. 67. (2002).
Frog (Rhacophorous sp). Science & Vie. 1023, 42 (December 2002)
Chameleon. Cover photo for novel, Faking It by Nigel Planar. Arrow (Random House, UK), London. (2003).
Clam fossil. Mary Blocksma. What’s on the Beach? A Great Lakes Treasure Hunt. Beaver Island Arts, Bay City, MI. 28 (2003).
California king snake. HSU Natural History Museum membership brochure. (2003).
Allosaurus skull cast. HSU Natural History Museum membership brochure. (2003).
Four photos of students working in labs. HSU CNRS brochure. (2003).
Astrolabe. Eric Evans. Domain-Driven Design. Addison-Wesley, Boston. 47 (2004).
Fern fossil. Joseph Raver. Biology: Patterns and Processes of Life. J. M. Le Bel Publishers. 163, 175. (2004).
1893 Zeiss Abbe vs. B&L Abbe 3L Refractometer. NUNCIUS Annali di Storia della Scienza, XIX, fasc. 2 (2004).
Pulfrish Refractometer by Hilger. NUNCIUS Annali di Storia della Scienza, XIX, fasc. 2 (2004).
Astrolabe (photo on cover and in text). Linda Formichelli and W. Eric Martin. Tools of Timekeeping. Nomad Press, White River Junction, VT (2005).
Water clock (photo on cover). Linda Formichelli and W. Eric Martin. Tools of Timekeeping. Nomad Press, White River Junction, VT (2005).
Armillary sphere. Leigh Atkinson, “When the Pope was a Mathematician”, The College Mathematics Journal 36 (5 November 2005) p 360.
Brachiopod (Platystophia acutilirata). "Ice-Age Survivors" Arts & Sciences Magazine. 3(1) Johns Hopkins University (Fall 2005).
Tangent galvanometer. Alan Giambattista et. al. : College Physics 2/e. McGraw-Hill, New York. (2006).
Zeiss Refractometer, circa 1920. Board on Physics and Astronomy. Instrumentation for a Better Tomorrow (Proceedings of a Symposium in Honor of Arnold Beckman). National Academies Press, Washington, D.C. (2006) p 19.
Kamal. John B. Hattendorf (ed.). The Oxford Encyclopedia of Maritime History. Oxford University Press, Oxford (2007).
Mariner's Astrolabe (digital image with components labeled). John B. Hattendorf (ed.). The Oxford Encyclopedia of Maritime History. Oxford University Press, Oxford (2007).
Vernier sextant (digital image with components labeled). John B. Hattendorf (ed.). The Oxford Encyclopedia of Maritime History. Oxford University Press, Oxford (2007).
Fifeteen fossil images on the cover of the Summer 2007 HSU Extended Education catalog (2007).
Photo of fossilized leaf of the redwood, Sequoia, World Encyclopedia of Fossils and Fossil Collecting Anness Publishing Ltd (2007?).
Five still photographic images of Permian-era fossils for use in Evergreen Films, LLC video production, Faces of the Earth for the Discovery Channel. (2007?)
Blue Pacific Tree Frog image for HSU Natural History Museum post card (June 2008).
Medieval mariner's compass replica (digital image) in The Art, Science, and Technology of Medieval Travel. Robert Bork and Andrea Kann (ed.). Ashgate (2008).
Mariner's quadrant replica (digital image with components labeled) in The Art, Science, and Technology of Medieval Travel. Robert Bork and Andrea Kann (ed.). Ashgate (2008).
Early mariner's astrolabe replica (digital image with components labeled) in The Art, Science, and Technology of Medieval Travel. Robert Bork and Andrea Kann (ed.). Ashgate (2008).
Mariner's astrolabe replica (digital image with components labeled) in The Art, Science, and Technology of Medieval Travel. Robert Bork and Andrea Kann (ed.). Ashgate (2008).
Kamal replica (digital image) in The Art, Science, and Technology of Medieval Travel. Robert Bork and Andrea Kann (ed.). Ashgate (2008).
Cross-staff replica (digital image) in The Art, Science, and Technology of Medieval Travel. Robert Bork and Andrea Kann (ed.). Ashgate (2008).
Fossil Sea Cucumber (digital image). Dr. Carl Werner. Living Fossils; Evolution : The Grande Experiment Vol. 2. New Leaf Press, Green Forest (2009).
Seafloor Assemblage photograph published in How Life Works,W.H. Freeman and Co. (2012)
Three photographs of fossils (Gastropod Busycon contrariuim (#464), Bivalve Chlamya (#439), and Pliocene echinoid (#458)) published in Wicande and Monroe, Historical Geology, 7th ed. Cengage Learning (2012).
Marbled Salamander (Ambystoma opacum) photo published in Become A Citizen Scientist brochure from the Grandview Chase Condominium Association and Penn State Extension, Lancaster, PA (2014).
Gastroliths photo published in Sally Lee. Apatosaurus. Capstone, Mankato (2015).
Richard A. Paselk, Richard Harper, and John B. Russell. Visualization of the Abstract in Chemistry. Presentation to the Chemistry editors and their associates of McGraw-Hill Inc., McGraw-Hill Building, New York, NY (Nov. 15, 1989).
Richard A. Paselk, Richard Harper, Mervin P. Hanson, and John B. Russell. Visualization of the Abstract in Chemistry. Presentation to the Apple Computer Corp. Higher Education Group, Apple Higher Education Building, Cupertino, CA (January 10, 1990).
Richard A. Paselk and Richard Harper. Visualization of the Abstract in Chemistry. Presentation to the Chemistry editors and their associates of The Benjamin/Cummings Publishing Company, Stanford Court Hotel, San Francisco, CA (February 29, 1990).