Prof. David Rosen


Prof. David Rosen

David Rosen
See also: David Rosen

20 April, 1936 - 8 January, 1997



See also: David Rosen

Obituary by M. Rose

David Rosen

The Hebrew University at Rehovot

International leader and educator: Biological control by natural enemies

(1936 - 1997)

Dave Rosen and Paul DeBach dedicated their 1979 book, Species of Aphytis of the World, to P.H. Timberlake. The final line in the dedication reads, "He is an inspiration to all who know him, and his dedication emphasizes the fascination of systematics that grips many of us". These heartfelt words of praise are a fitting epitaph for Dave; he was inspired by those he admired, he emulated their ideals and, through his knowledge, thoughtfulness and dedication, became an inspiration to the many he touched through his colleagueship, his lectures, his written works and his friendships.

Dave Rosen and Paul DeBach were my mentors and best friends since we began working together at U.C. Riverside in 1968. As we were first of all friends, I must begin this short memorium with a few personal remarks. The sense of loss that accompanies the death of a friend with whom you have shared most of your personal and professional life is profound. When Dave and I last shared time and a drink in his new home in Rehovot, Israel, we talked about our grief following the death of Paul DeBach in 1992; and how we both so wanted to continue to contribute to biological control in ways that would honor our friend and mentor. We then made our plans to work together during Dave's sabbatical the following year in Montana. That year has come and gone, but the loss of Dave will go forever on.

Dave was a student at the Hebrew University of Jerusalem and studied under the late Professor Z. Avidov (MSc., 1959) and the late Israel Cohen (PhD., 1966); his PhD studies concerned the natural enemies of scale insects on citrus. These early studies lead Dave to his life's work; systematics and biological control. In 1966 Dave began post-doctoral studies with Paul DeBach at U.C. Riverside. This collaboration continued until Professor DeBach died in 1992. Together they wrote Species of Aphytis of the World (1979); for which they were awarded the first Gold Medal for outstanding contribution to biological control, presented by the Filippo Silvestri Foundation in Naples. In 1984, they published the second edition of Biological Control by Natural Enemies, which is a widely used text. In addition to the two books he wrote with Paul DeBach, Dave published 140 scientific papers, 33 book chapters and authored or edited an additional six books. And, he was finalizing the editing of another book, Readings in Biological Pest Control, at the time of his death. This work will be published by Itercept, Andover, UK.

Dave taught courses in biological control, systematic zoology, general entomology, pest management and orchard entomology at the Hebrew University in Rehovot and conducted research on many aspects of systematics and biology of parasites, particularly Aphytis. He was active both nationally and internationally in biological control and IPM programs, and was a much sought organizer and speaker at international conferences and symposia. He was Visiting Professor and Scientist at numerous institutions and he presented seminars and seminar series in biological control at the University of California, the University of Maryland, Texas A&M University and the University of Ankara (Turkey). He also conducted a seminar series on Special Topics in Entomology at the University of Florida.

The energy, production and hard-hitting, but eloquent perception that Dave brought to the biological control community are missed, as is the leadership that persons with such attributes provide. At the 1994 National ESA meetings in Baltimore, for example, Dave called upon the biological control community to fulfill the need to practice classical biological control; rather than theorize about possible "new" approaches. At the 1996 International Congress in China, he championed the outstanding history of applied biological control, and emphasized the need to continue to discover and implement natural enemies as the first and most effective means to develop sustainable, ecologically-based pest management systems. Dave worked with a conscious and sustained effort to do things right; right by his friends, right by his science and right by the environment.

There are innumerable stories to be told by the many of us who worked with Dave over the years; stories about exploration for natural enemies, meetings at exotic places, discoveries at the microscope and just plain good times. These cannot all be expressed here. But, a moment's reflection about Dave Rosen will bring to mind the best reasons for abiding friendships, the importance of international collaboration and the wonders of the science and practice of biological control by natural enemies.

submitted by Mike Rose

Appeared in International Organization for Biological ControlNearctic regional section NewsletterSummer 1998, Volume 20, No. 2.

See also: David Rosen

Obituary by M. Coll

David Rosen

David was born in Tel Aviv on 20 April 1936 and received his academic training at the Faculty of Agriculture, the Hebrew University of Jerusalem. For many years, he advanced the use of biological control within the framework of an integrated approach to insect pest control. David was always sure to express his views on theoretical as well as applied issues in biocontrol, even when in the minority.  David Rosen wrote or edited 8 books (2 more are yet to be published) and authored or co-authored 200 book chapters and research papers. David was also a gifted teacher and was yearly recognized as such by students and administrators. Recently, he was honored with the Rector's award for many years of excellence in teaching. David was warm and outgoing. He had a great sense of humor and a story to tell for every occasion. He fought his last battle against a malignant illness with realism, courage and optimism that characterized his life and career. Despite physical difficulties, David attended six international meetings during the last year of his life and was professionally active until his last day. David had a vast impact on the development of plant protection in Israel, an impact that will be long-lasting through his own contributions and the continuing efforts of his 33 M.Sc. and 20 Ph.D. students. His untimely departure leaves a great void. His leadership, inspiration, and friendship will be greatly missed by colleagues, students, and many friends around the world.

By Moshe Coll

Book dedication – Predatory Heteroptera: Their Ecology and Use in Biological Control. M Coll & JR Ruberson, eds. Entomol. Soc. Am. 1998.

See also: David Rosen

Obituary by D. Gerling and M. Wysoki

David Rosen (1936-1997)

David Rosen, The Vigevani Professor of Agriculture and Professor of Entomology at the Faculty of Agriculture of the Hebrew University of Jerusalem, and World leader in chalcidoid taxonomy and biological control of insect pests, died on 8 January 1997 after a brave struggle with cancer. David was born in Tel Aviv, Israel in 1936. He pursued his scientific studies at the Hebrew University where he obtained his M.Sc. degree summa cum laude in 1959 and his Ph.D. in agricultural entomology in 1965. David remained a permanent staff member of the Faculty of Agriculture, rising quickly from the rank of lecturer in 1967 to Full Professor in 1978. In 1990 he became the first appointee of the Vigevani Chair in Agriculture. He chaired the Department of Entomology, first as acting chairman (1974) and then as elected chairman, from 1977 to 1980 and from 1992 on, resigning from his second term after discovering his illness in 1995. In addition to his duties as chairman, David was very involved in University life. He was active on numerous committees as well as being Director of the Research Center for Integrated Pest Management from 1988 on. He was also deeply involved in teaching, both at the administrative level, where he contributed measurably to the shaping of future teaching curricula in plant protection, and at the personal level where he was known as an excellent teacher and lecturer at home and abroad. His death came only a few days before he would have been awarded the M. Millikan Prize for Distinction in Teaching in recognition of his excellence.

Throughout his career, David devoted a large part of his time to improving Israeli agriculture. He contributed measurably to the introduction and improvement of biological and integrated pest control methodology. His awareness of environmental problems culminated in his heading a committee appointed by the chief scientist for the Ministry of Agriculture, to examine the possibilities of reducing the use of poisonous pesticides in agriculture. For this purpose, he assembled a committee comprising leading scientists and extension service, plant protection and inspection service officers together with producers of plant protection products. The committee's report that was published in 1990 after almost two years of deliberations, reflected his leadership, excellent ideas and superb penmanship, and served as an important landmark in plant protection in Israel.

David was an active member of the Entomological Society of Israel since its establishment and served on its committees till the last day of his life. He was also a member of the editorial board of the Society Journal: The Israel Journal of Entomology.

On the international level, David was well known as one of the proponents and leaders in biological pest control. He was an active member of the IOBC and a member of the IOBC\WPRS Council, leaving his mark on many of its decisions. He also served as a member of the FAO\UNEP Inter-national Panel of Experts on Integrated Pest Control. His active participation in the International Plant Protection Congresses led the organizing com-mittee to elect him chairman for the next (14th) meeting in 1999, to be held in Israel. His international contributions included editorial duties in numerous professional publications including: Annual Review of Entomology, Biological Control, Entomophaga, Integrated Pest Management Reviews, and The Journal of Hymenoptera Research. David took also an important part in the International Congresses of Entomology, in which, for the last 20 years, he organized symposia and participated as an invited speaker in numerous forums. During the 20th Congress, held last summer in Firenze, Italy, he was elected to replace Professor R. Galun as a member of the organizing committee for the 21st Congress.

He traveled extensively in the Americas, Europe, the CIS, the Far East and Australia and fulfilled many international appointments. These included visiting Professorships of Entomology at the University of California in Berkeley and Riverside, the Universities of Ankara and Adana in Turkey, the University of Maryland in College Park, Texas A&M University in College Station, and the University of Florida in Gainesville.

David has published widely in Hebrew and English. His scientific contributions include 164 refereed articles, and seven books that are listed at the end of this article. The latter include two books that he co-authored with Paul DeBach, and five books that he edited.

David was a well known taxonomist of parasitic Hymenoptera, and was known both as a specialist of Encyrtidae and Aphelinidae, and as a strong proponent of recognizing the importance of taxonomy for biological sciences in general and biological control in particular. His taxonomic contributions culminated in 1979 in the publication of a revisionary book on the genus Aphytis co-authored with Professor Paul DeBach. This work gained the authors the prestigious Filippo Silvestri Foundation prize from the University of Naples.

David was a proud Israeli, believing in the right of all peoples to live freely in their homeland. He will also be remembered as speaking up, on many occasions, in favour of separating science from politics. He was a family man, a good husband and proud father to his three children. During the last few years he could often be seen in the company of his wife, Mazal, at many professional meetings. The many students and scientists, whom he supervised for both M.Sc. and Ph.D. degrees, as well as his colleagues in Israel and abroad, will always remember David as an exemplary family man, a true friend and a brilliant colleague who was always ready to contribute and help with his wisdom, humour and scientific insight. Together with his family and the scientists' community we shall sorely miss him.

Books authored or edited by Professor D. Rosen:

  • Rosen, D.; DeBach, P. (1979) The species of Aphytis of the World, Hymenoptera, Aphelinidae. Jerusalem; Israel Universities Press andThe Hague, Netherlands; W. Junk, 801 pp.
  • DeBach, P.; Rosen, D. (1991) Biological control by natural enemies. Cambridge, UK; Cambridge University Press, 440 pp.
  • Rosen, D. (1990) (ed) Report of the steering committee of reducing use of pesticides in agriculture. Rehovot, Israel; Chief Scientist, Faculty of Agriculture, 148 pp. [in Hebrew]
  • Rosen, D. (ed) 1990 Armored scale insects their biology, natural enemies and control. World Crop Pests. Amsterdam, Oxford, New York, Tokyo; Elsevier, Volume A, 384 pp. and Volume B, 688 pp.
  • Rosen, D.; Bennet, F.D.; Capinera, J.L. (eds) (1994) Pest management in the subtropics: biological control - a Florida perspective. Andover, UK; Intercept Ltd, Volume I, 737 pp.
  • Rosen, D.; Bennet, F.D.; Capinera J.L. (eds) (1996) Pest management in the subtropics: integrated pest management - a Florida perspective. Andover, UK; Intercept Ltd, Volume II, 578 pp.
  • Rosen, D.; DeBach, P. (eds) (1994) Advances in the study of Aphytis (Hymenoptera: Aphelinidae). Andover, UK; Intercept Ltd, 362 pp.

By Dan Gerling and Manes Wysoki

Appeared in: Biocontrol News and Information, June 1997, Volume 18 No. 2.

See also: David Rosen

Obituary by U. Gerson and S. W. Applebaum

David Rosen


 David Rosen, First Incumbent of the Vigevani Chair of Agriculture, and Professor of

Entomology at the Faculty of Agricultural, Food and Environmental Quality Sciences at the Rehovot campus of The Hebrew University of Jerusalem, passed away on January 8, 1997, after a prolonged illness.

David was born in Tel-Aviv on April 20, 1936, the only child of Josef and Fela Rosen. After graduating from high school in Tel-Aviv, he began his agricultural studies at The Hebrew University of Jerusalem. In 1959 he submitted a Master’s Thesis in Plant Protection, based on research conducted under the supervision of the late Professor Z. Avidov, and was awarded the degree “with excellence”. This was the period when local citricultural research was promoted by the late Israel Cohen of the Citrus Marketing Board, a man of vision who had earlier been instrumental in the successful biological control of a major citrus pest. Cohen enthusiastically supported David in his Ph.D. studies on the natural enemies of citrus scale insects. This in turn stimulated David’s interest in all aspects of biological control, with special emphasis on systematics. While developing his taxonomic skills David established contacts with specialists worldwide, especially with Professor Paul DeBach of the University of California at Riverside. In 1964 he completed his Ph.D. studies and shortly afterwards (1965) was awarded the Jacobson Prize for research on citrus. In 1966 he began his postdoctoral studies with Paul DeBach at Riverside. At that time they began their collaborative studies on the systematics of parasitic wasps of the genus Aphytis, which culminated in 1977 with the publication of their monumental monograph, “Species of Aphytis of the World”. The book won them First Prize (gold medal), of the Filippo Silvestri Foundation, Naples. heir fruitful association and deep friendship continued for many years, until Professor DeBach’s death in 1992.

Following his return to Rehovot, David developed and taught a very successful and popular course in Biological Control. In 1967 he was appointed Lecturer in Agricultural Entomology. By then David had begun to be widely known, as attested to by his appointment in 1968 as a member of the International Working Group for Biological Control of Citrus Coccids and Whiteflies, of the Organisation International de Lutte Biologique (OILB), as well as to the Advisory Panel of the International Biological Program (IBP) Project for Biological Control of Armored Scale Insects. During the years 1968–70 he returned to Riverside to work with DeBach. His next promotion (1971) at the Hebrew University was to Senior Lecturer in Entomology. He was elected and served as chairman of the Teaching Program in Plant Protection until 1973.

His interest in taxonomy led him at that time to propose and teach another very popular new course, Principles of Systematic Zoology. In 1974 he was promoted to Associate Professor of Entomology and elected acting Chairman, Department of Entomology; he was promoted to Professor and during 1977–80 served as Chairman of the Department.  In 1981 he lectured at the International Centre for Insect Physiology and Ecology in a Group Training Course in Pest and Vector Management, Nairobi, Kenya. During the same year he was appointed a Visiting Professor of Entomology, Department of Entomological Sciences, University of California, Berkeley, and invited to become a member of the Editorial Committee, responsible for the organization of Vol. 29, “Annual Review of Entomology”. In 1983 he was a Visiting Professor of Entomology, University of Maryland, College Park, as well as a Cooperating Scientist, Beltsville Agricultural Research Center, USDA (Maryland). Furthermore, he was appointed a member of the FAO/UNEP International Panel of Experts on Integrated Pest Control, Rome. In 1985 he was appointed a member of the Scientific Committee, Bollettino del Laboratorio di Entomologia Agraria “Filippo Silvestri” di Portici, Italy, a member of the Editorial Board of “Entomophaga”, published by IOBC, and a member of the International Advisory Council for Biosystematic Services in Entomology, representing the Middle East Region. In 1986 David was appointed as the representative of the Israel National Academy of Sciences to the International Organization of Biological Control, West-Palearctic Region (IOBC/WPRS) as well as a member of the Scientific and Technical Committee, “Parasitis 86”, Geneva, Switzerland. In 1988 he was appointed Director, The Hebrew University Research Center for Integrated Pest Management, and to the Advisory Board of International Correspondents, “Annual Review of Entomology”. By 1989 he was appointed a member of the Editorial Board of “Phytoparasitica”; elected Subject Editor for Biological Control for the “Journal of Hymenoptera Research”, and attended the General Assembly of IOBC/WPRS (Firenze), where he was elected Deputy Member of Council for 1989–93.

David Rosen was appointed First Incumbent, the Vigevani Chair of Agriculture, The Hebrew University of Jerusalem, in 1990.He was appointed a Charter Member of the Editorial Board of the periodical “Biological Control”; visited the Soviet Union upon being invited by the Zoological Institute, Academy of Sciences, Leningrad; and delivered lectures at the Institutes of Plant Protection, Tbilisi (Georgia) and Pushkin (Russia). He spent the following year as a Visiting Professor of Biological Control, University of Florida, Gainesville. In 1992 David traveled to the Republic of Kazakhstan, in order to establish cooperation under the auspices of USAID/CDR (the United States Agency for International Development/Cooperative Research and Development program). In 1993 he was appointed to the Board of Directors of the Chinese-Israeli Center for Training in Agriculture, Beijing. He also visited Berlin, on the invitation of the Federal Ministry of Environment, for discussions of collaborative research, and later attended the General Assembly of IOBC/WPRS (Lisbon), there to be re-elected Deputy Member of Council for the years 1993–97. Finally, he was appointed a member of the Editorial Board, “Integrated Pest Management Reviews”, and in 1994 was appointed to the Academic Council, The College of Judea and Samaria, Ariel (Israel).

David attended many congresses, at which he was a sought-after personality and fulfilled many important functions. In 1974 he represented the Israel Ministry of Agriculture at an EPPO (European Plant Protection Organization) Conference on Integrated Control in Horticultural Crops (Kiev). In 1976 he organized and moderated the symposium on the role of hyperparasitism in biological control (15th Int. Congr. Entomology, Washington, DC). In 1980 he presented an invited paper at the 16th Int. Congr. Entomology (Kyoto). In 1984 he organized and moderated a symposium on incorporation of biological control in integrated pest management programs (17th Int. Congr. Entomology, Hamburg).In 1980 he organized and moderated a symposium on genetic manipulation of arthropod biological control agents (18th Int. Congr. Entomology, Vancouver). In 1990 David participated in the Sixth Int. Symp. of Scale Insect Studies (Krakow) and in 1991 in the 12th Int. Plant Protection Congr. (Rio de Janeiro). In 1992 he attended a Workshop on Biological Control of Coca at the Office of Technology Assessment, U.S. Congress (Washington, DC); chaired the session on Biological Control at the Seventh Int. Congr. of Citriculture; presented an invited paper at the meeting of the IOBC/WPRS Working Group on Integrated Control of Citrus Pests (Acireale, Italy); and organized and moderated a symposium on Advances in the Study of Aphytis at the 19th Int. Congr. Entomology (Beijing). In 1995 David attended the Nicholson Centenary Meeting, “Frontiers in Population Ecology” (Canberra) and presented invited lectures in Australia. He later delivered a paper at the 13th Int. Plant Protection Congr. (The Hague), where he invited the next IPPC to Jerusalem for the year 1999. Upon acceptance of this invitation he was appointed Chairman of the Organizing Committee. Finally, he presented two invited papers at the Int. Symp. on “Citrus Health in the Mediterranean Area”(Valencia).

Throughout his professional life David was a proponent of principles and philosophy of biological pest control. However, he was far from being a fanatical adherent of this discipline, realizing quite early that natural enemies alone may often not suffice for adequate pest control. For this reason he always advocated integrated pest management, and, among other topics, studied the effects of agricultural chemicals on natural enemies. In his later years he became interested in the use of pesticide-resistant natural enemies, promoting their study in Israel and abroad; and also in the biology of several pests of cotton and solanaceous crops – potatoes and processing tomatoes, and contributed his expertise to control projects undertaken in developing countries.

Professor David Rosen had a vast impact on the development of Plant Protection in Israel and abroad, inspired many students, and wrote or edited several significant books. His impact may be realized from the fact that he participated in, or chaired many committees in Israel concerned with various aspects of pest control. Among others, these included an Advisory Committee for Citrus Pest Control, a Committee on New Pests, Governing Board of the Plant Protection Branch and Chairman of the National Steering Committee for Reduction of Pesticide Use, all at the Ministry of Agriculture; the Steering Committee of the Biological Control Institute (Citrus Marketing Board); the Committee for Integrated Pest Management of the Fruit Board of Israel; the Organizing Committee of the International Conference on Modern Agriculture and the Environment, Rehovot, and recently served as Chairman of the Steering Committee, Agritech Agro-Ecology Conference, Tel Aviv.

During his scientific career, he supervised 20 Ph.D. and 33 M.Sc. students, many of them jointly with colleagues. He published 140 Research and Review Papers in scientific journals, 33 Chapters in Books, and authored or edited the following 8 books:

  • Rosen, D. and DeBach, P. (1979) Species of Aphytis of the World (Hymenoptera: Aphelinidae). Israel Universities Press, Jerusalem, and W. Junk, The Hague, The Netherlands,ix+801 pp.,1342 figs.
  • Rosen, D. [Editor] (1981) The Role of Hyperparasitism in Biological Control: a Symposium. University of California Division of Agricultural Sciences, Riverside, CA, Publication 4103, 52 pp.
  • Rosen, D. [Editor] (1990) Armored Scale Insects: Their Biology, Natural Enemies and Control. World Crop Pests series, Volumes 4A,xvi+384 pp., and 4B,xxvi+688 pp., Elsevier Science Publishers, Amsterdam, The Netherlands.
  • DeBach, P. and Rosen, D. (1991) Biological Control by Natural Enemies.2nd ed. Cambridge University Press,Cambridge,UK,xv+440 pp.
  • Rosen, D., Bennett, F.D. and Capinera, J.L. [Editors] (1994) Pest Management in the Subtropics: Biological Control –a Florida Perspective. Intercept, Andover, UK,xiv+737 pp.
  • Rosen, D. [Editor] (1994) Advances in the Study of Aphytis (Hymenoptera: Aphelinidae). Intercept, Andover, UK, xiii+362 pp.
  • Rosen, D., Bennett, F.D. and Capinera, J.L. [Editors] (1996) Pest Management in the Subtropics: IPM –a Florida Perspective. Intercept, Andover, UK.
  • Rosen, D., Tel-Or, E., Hadar, Y. and Chen, Y. [Editors] Modern Agriculture and the Environment. Kluwer Press, Amsterdam, The Netherlands (in press).

Lastly, David had almost completed editing yet another book, “Readings in Biological Pest Control”, which is to be published by Intercept, Andover, UK. David was awarded numerous competitive research grants, most of them for research on hymenopterous parasites of scale insects. These included grants from the Israel National Academy of Sciences and Humanities, Agricultural Research Organization (Israel), U.S. Department of Agriculture, U.S. Agency for International Development for Research, U.S.-Israel Binational Science Foundation (BSF) and U.S.-Israel Binational Foundation for Agricultural Research and Development (BARD).

David was a gifted teacher. He taught courses at Rehovot in General Entomology, Introduction to Pest Management, Orchard Entomology and Biological Control, and led seminars in Biological Control and in Insect Ecology and Biological Control at the University of California, University of Maryland, Texas A&M University; and the University of Ankara (Turkey); he conducted a seminar on Special Topics in Entomology at the University of Florida. His superb teaching was yearly recognized by the students and the Dean of his Faculty in Rehovot. Shortly before he passed away he was awarded a certificate from the Rector of The Hebrew University of Jerusalem citing his outstanding teaching qualities and contributions over many years.

David was very public-spirited and a willing member of several committees during his career, and served as Chairman of the Cultural Affairs Committee, of the Academic Program on the Committee for International Academic Relations, of the Committee for the 50th Anniversary of the Faculty of Agriculture and of the Center for Integrated Pest Management. David was a member of many learned scientific societies, including the Entomological Society of America, the Royal Entomological Society of London, the International Organization for Biological Control of Noxious Animals and Plants, the International Society of Chemical Ecology, the Entomological Society of Southern Africa and the Entomological Society of Israel. 

Despite his illness, David kept very busy even during the last weeks of his life. He insisted on continuing to teach and to supervise several of his students. David regularly chaired the meetings of the IPPC Organizing Committee, and carefully read through the final chapters of the Hebrew version of his book “Biological Control by Natural Enemies”, translated (to his great joy) by his children. This was greatly facilitated by his very clear, almost “print ready” handwriting. David Rosen held firm, and strongly-expressed, political views. A chance to combine these tenets with his academic credentials and standing arose when he was asked to serve, as he gladly did, on the Academic Council of The College of Judea and Samaria, at Ariel. David had a true collector’s spirit, collecting (besides stamps and coins) antique entomological books. The latter (some dating to the early 19th Century) were prominently displayed in his office, and were a source of endless pride and citations. 

A special chapter in his professional life was associated with our colleague, the late Professor Haggai Podoler. Haggai was an ecologist and co-operated with David in many projects. They supervised numerous students together. Upon Haggai’s very untimely passing, David undertook to care for all of Haggai’s students. He also organized the yearly commemorative meeting for Haggai.

 David had an outgoing personality and loved attending parties. He had a great sense of humor; being a born raconteur every meeting with him was accompanied by at least one of his jokes (some of which were incorporated into his lectures). David is survived by his wife Mazal, his staunch companion since 1958, and their three children, Orna, Sefy and Nurit, and three grandchildren. David had very many friends in Israel and abroad, and we all mourn the passing of a good friend, a scientific authority of international repute, and a wonderful teacher.

By Uri Gerson and Shalom W. Applebaum

Appeared in: Phytoparasitica 25:2, 1997

View as PDF

See also: David Rosen