RESEARCH NEWS

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dered subsequence of DNA that twoDNA molecules have in common. Ifthedtwo DNA molecules consist of innucleotides and n nucleotides, respec-tivcly, an algorithm can find their long-est --ommon ordered subsequence in inttimes in steps. However, Peter Wienerof the Rand Corporation in SantaMonica, California, has now found analgorithm that can perform this opera-tion in m + n steps, a considerablesaving if in and n are large.Wiener made two assumptions that

enabled him to find an algorithm con-

sisting of mi + n steps. Neither assump-tion was included in the algorithm thatrequires inn steps. First, Wiener as-sumed that the algorithm must findonly contiguous subsequences of DNA.(Because the genetic code is translatedfrom contiguous sequences, it is notacceptable to choose a subsequenceconsisting of DNA nucleotides that areseparated from each other on the DNAstrand.) Second, Wiener assumed thatthe algorithm would be run on a ran-dom access computer-a computer witha large core memory that enables it to

quickly recall information that is askedfor by name. Computers with auxiliarymemories, such as tape or drum mem-ories, recall information much more

slowly. Wiener's solution is thus ex-

tremely helpful to those who need thisspecial case of the algorithm for re-search on molecular evolution and whohave random access computers. It doesnot aid those who need the more gen-eral algorithm or who have more re-stricted computers. Although researchon special cases usually precedes thedevelopment of unifying theories, uni-fying theories have not as yet beenproposed for problems involving com-puter algorithms.

Ronald Graham of Bell Laboratoriesin Murray Hill, New Jersey, believesthat the lack of combinatorial theoriesis due in part to the fact that com-bfnatorics has traditionally not beenconsidered a subject unto itself. Onlyrepently, he says, have researchersemphasized the unity of combinatorics.Moreover, the large number of as yetunsolved problems makes it difficultto build theories. However, the recentrapid development of combinatorics isencouraging to those who, like Rota,believe that combinatorial theories are

necessary to the future of the mathe-matical, physical, and life sciences.

-GINA BARI KOLATA

1MARCH 1974

|||||||||||||||POSITIONS WANTED l|||||0|p|||

Biochemist, Ph.D. Experienced in heart andcancer research. With background in membranetransport, nucleic acid metabolism, oxidativephosphorylation, microsomal drug-metabolizingenzymes, cyclic nucleotides. Seeking research,teaching, or both. Box 107, SCIENCE. X

Biochemist, Ph.D. 1968. Postdoctoral experiencein polysaccharides, glycoproteins, mucopoly-saccharides. Synthetic carbohydrate chemistry,analytical biochemistry. Teaching experience.Seeks academic, industrial, or clinical position.Prefer major metropolitan area. Box 108,SCIENCE. X

Biochemist, Ph.D. 1972. Postdoctoral experiencein lipid neuLrochemistry-metabolism. Strong ana-lytical background in lipid methodology. Severalpublications. Desires academic, postdoctoral, orinidustrial position in New York State or NewEngland. Box 17, SCIENCE. 3/1

Biochemist-Microbiologist. Ph.D. (biochemistry).Six years of teaching (graduate and medical),research guidance, administrative experience, pub-lications in biochemical pharmacology, microbialpathogenicity, antibiotics, nucleic acids, carbo-hydrates. Seeking a challenging position in re-search-teaching-administration. Box 90, SCI-ENCE. 3/1

Electron Microscopist, M.S., with E.M. research,teaching and equipment maintenance experience.Desires position involved in these areas andlaboratory management. Donald Bechtel, Depart-ment of Botany and Plant Pathology, Iowa StateUniversity, Ames, Iowa 50010.

Experimental Pathology, Ph.D. 1969; 3½2 yearsin pharmacology department. Experience in im-munology, cell culture, electron microscopy, toxi-cology; seeks challenging industrial position. Box109, SCIENCE. X

Fermentation Biochemist, Ph.D. 1967; 3 years ofpilot plant research, 4 years' selling experienceof investment properties. Seeks pharmaceuticalmarketing, scientific liaison. Chinese, permanentresidence, multilingual. Box 689, HuntingtonBeach, California 92648. 3/8

Geneticist Biostatistician, Ph.D. Experienced,effective versatile teacher with research and ad-ministrative experience; presently associate pro-fessor at major university; seeks position in small,liberal arts college. Box 110, SCIENCE. X

Broadly trained Geneticist. Ph.D. 1965. Twoyears of postdoctoral training; 38. Outstandingteacher, 15 years of professional experience.Special interest innovative undergraduate pro-grams. 2266 Lake Circle, Jackson, Mississippi39211. 3/1, 29

It is requested that only those employerswho will not discriminote on the basis ofrace, sex, religion, color, or national originsubmit positions open advertising.POSITIONS WANTED: 40e per word, mini.mum charge $10. Use of Box Numbercounts as 10 additional words. PaymentIn advance Is required. These rates applyto individuals only. Personnel agencies andcompanies take display rate for all adver-tising.

POSITIONS OPEN: $110 per inch. No chargefor Box Number. Rates net. No agencycommission allowed for ads under 4 Inches.No cash discount. Ads over 1 inch will bebilled to the nearest half inch. Payment Inadvance is required except where satis-factory credit has been established.

COPY for ads must reach SCIENCE 4 weeksbefore issue date (Friday of every week).Send copy for Personnel Placement adver-tising to:

SCIENCE, Room 2111515 Massachusetts Ave., NW

Washington, D.C. 20005Replies to blind ads should be addressed

as follows:Box (give number)SCIENCE1515 Massachusetts Ave., NWWashington, D.C. 20005

A position will be available 1 July 1974 inWayne State University's School of Medicine,for M.D., Board certified in Internal Medicine,trained in pulmonary diseases, primarily to workin respiratory support unit. Responsibilities willinclude teaching, research, and related clinicalcare. Applications with curriculum vitae, bibliog-raphy and any other pertinent information shouldbe sent to: Dr. V. K. Vaitkevicius, Professor ofMedicine, Chief of Medicine, Grace Hospital,4160 John R Street, Detroit, Michigan 48201.

883

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PersonnelPlacement

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Immunologist, Ph.D. 1974. Desires teaching andresearch position as assistant professor or im-munology or of microbiology in a medical orgraduate school department. Publications in im-munology. Research interests include tumorimmiiunology, the macrophage, B- and T-cell inter-actions in the immune phenomena. Box 111,SCIENCE. X

Laboratory Manager. Ph.D. (analytical chemistry).with 6 years of experience in laboratory super-vision for pharmaceuticals and health industryproduLcts. Solid background in quality control,product development and FDA/GMP regulations.This innovative scientist seeks challenging posi-tion in technical management. Presently em-ployed. Box 112. SCIENCE. X

Pharmacology. Ph.D. 1968. Background in ana-lytical chemistry, drug metabolism, and neuro-chemistry. Several publications. Seeks challengingposition in university or position with researchopportunity. Box 113, SCIENCE. X

Physical-Inorganic Chemist. Ph.D. 1974. Exper-ienced in Mossbauer spectroscopy, ESCA, instru-mental design, computer programming, liquidhelium work, and some vacuum line techniques.Desires challenging teaching, research or indus-trial position. Box 114, SCIENCE. X

Physiological Psychologist/Electrophysiologist.Young Ph.D. with postdoctoral research experi-ence in learning and memory interested in re-search/academic position. Eight publications. Box102, SCIENCE. 3/1

Polymer Organic Chemist. Ph.D. 1960, withstrong biomedical background, extensive researchexperience in water-soluble and insoluble poly-peptides, biodegradable/nonbiodegradable poly-a-hydroxyacids, cyano-acrylates, and their charac-terization including successful applications inmedicine and surgery, with number of papersseeks immediate employment on research./aca-demic position of real challenge. Box 104, SCI-ENCE. 3/8

Quantitative Experimental Psychologist, Ph.D.;3 years of college teaching plus 5 years of full-time research experience. Twenty publications inhuman information processing and vision. Re-search or research and teaching position desiredwhere computer, mathemiiatics, and electronicskills can be utilized. Box 115, SCIENCE. X

Toxicologist. Ph.D. 1972. Seeks teaching and/orresearch position. Publications in environmentalhealth toxicology and immunology. Box 116,SCIENCE. X

IiNIIIIDIIIII POSITIONS OPEN lIIIIJlIIIIIIIIDIIIIASSISTANT PROFESSOR

Applications are invited from qualified personsholding Ph.D. and/or M.D. degrees to fill fourpositions, preferably at the Assistant Professorlevel, one in Neuroanatomy, one in Gross Anat-omy, one in Pharmacology, and one in Biochem-istry in the School of Basic Medical Sciences,Urbana-Champaign. Appropriate departmentalpredoctoral or postdoctoral training is essential.Each position carries a joint appointment in

one of the scientific departments on this campus.Teaching duties relate to curriculum developmentand supervision of medical student learning inan independent study program. Candidates musthave demonstrated their capacity for originalresearch as evidenced by publications of highquality.The University of Illinois is an equal oppor-

tunity employer and encourages applicationsfrom women and menibers of minority groups.Send applications, including curriculum vitae,

publication list, important reprints, and at leastthree letters of recommendation to Chairman,Search Committee, SBMS-UC, 1205 West Cali-fornia Street, University of Illinois, Urbana,Illinois 61801.

ASSISTANT PROFESSOR OF MEDICINE

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NEWFOUNDLANDASSISTANT PROFESSOR IN BIOCHEMISTRYApplications are invited for the post of Assist-

ant Professor in the Department of Biochen istry(Head Designate, Dr. C. C. Bigelow), totakeeffect from 1 September 1974 or as soon tlhere-after as possible. The Department teaches under-graduates in the Faculty of Science, and hasan active postgraduate research and teaching pro-gram. The successful applicant will be reqbiredto take part in the teaching duties of the De-partment, and to develop his own research pro-gram. The salary is negotiable, depending onexperience.

Applications, including a curriculum vitae andthe names of three referees, should be sent toDr. E. A. Barnsley, Department of Biochemistry,Memorial University of Newfoundland, St. John's,Newfoundland, Canada, to reach him not laterthan 31 March.

ASSISTANT PROFESSOR OF ONCOLOGYThree 1-year positions will be available 1 July

1974 in the School of Medicine of Wayne StateUniversity, for holders of the M.D. degree, Boardcertified in Internal Medicine. qualified or certi-fied in the subspecialty of oncology. Specialistsare required in the following areas:

1) Breast cancer management and experience inestrogen metabolism studies.

2) Experience in leukapheresis in conjunctionwith IBM Cell Separator, white cell typing, andleukokinetics.

3) Tumor immunologist with laboratory ex-perience in blocking antibody determination.

Responsibilities will include teaching, research,and related clinical care. Applications with curri-culum vitae, bibliography, and any other pertinentinformation, should be sent to: Dr. V. K. Vait-kevicius, Chairman, Department of Oncology,Wayne State University School of Medicine, 540East Canfield, Detroit, Michigan 48201.

ASSISTANT PROFESSOR-PLANT ECOLOGYApplications are invited for a new position inPlant Ecology, Ph.D. required. Duties to beginin September 1974. Primary teaching responsi-bilities will be to develop an integrated coursein ecology and to teach an advanced course infield of special interest. People with a stronginterest in research are especially invited toapply. Send curriculum vitae and three lettersof references by 1 April 1974 to Dr. C. F.Herreid, Department of Biology, State Universityof New York at Buffalo, Buffalo, New York14214.

An Equal Opportunity Employer/AffirmativeAction Employer

ASSISTANT PROFESSOR/PULMONARYUniversity of California, San Diego. Appointmentat the Assistant Professor level for a physicianwho has been completely trained in pulmonaryphysiology and medicine and who has publishedfundamental research in areas relating immunol-ogy to pulmonary disease. Will have responsibili-ties in teaching clinical pulmonary medicine andgeneral internal medicine; patient care in thesetwo areas; independent research in pulmonaryimmunology. Please forward curriculum vitaeand three lettters of reference by 31 March 1974.Respond to Dr. Helen Ranney, Chairman, De-partment of Medicine, University Hospital, 225West Dickdnson Street, San Diego, Calif. 92103.An Equal Opportunity/Affirmative Action Em-ployer.

ASSOCIATE CHIEF OF STAFF FOR RE-SEARCH, San Diego Veterans AdministrationHospital, and Faculty Member, University ofCalifomia, San Diego School of Medicine, LaJolla, Calif. Applications are sought for a physi-cian with the necessary scientific and admini-strative background to coordinate the fti*tdevelopment of the research program of this hos-pital. The candidate should be eligible for 'asenior academic appointment at the Universi.yof California, San Diego School of Mediciseand will be encouraged to participate in all "fthe activities of his particular department in themedical school and its hospitals.

The DEPARTMENT OF BIOLOGY at Hampden-Sydney College has an opening for either anInvertebrate Biologist or a Microbiologist. Ex-perience in Histology and/or Parasitology isdesirable. Candidates should have the Ph.D. degreeand preferably a few years of teaching behindthem. Hampden-Sydney College is a small (700students), liberal arts college for men in south-side Virginia. The emphasis is on undergraduateteaching. The sciences are housed in a newbuilding with excellent teaching and researchfacilities. Interested candidates should contactDr. T. H. Tumey, Box 157, Hampden-Sydney,Virginia 23943.

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