© 1999 Macmillan Magazines Ltd

correspondence

NATURE | VOL 398 | 15 APRIL 1999 | www.nature.com 555

Sir — Your columns have includedspeculation that the International AIDSSociety might countenance a boycott of theInternational Conference on AIDS to beheld in Durban, South Africa in July 2000(Nature 398, 8; 1999). This issue has arisenbecause of the refusal of the South Africangovernment to routinely offer antiretroviraldrugs (ARVs) to HIV-infected pregnantwomen, in spite of the fact that shortcourses of ARVs towards the end ofpregnancy can reduce the likelihood of HIVtransmission to infants by up to 75 per cent.

We are firmly opposed to a boycott,which would only harm the interests ofthose whom the well-intentionedproponents of this idea would seek to serve.

The South African government has beenaccused of “the murder of babies” and ofhaving a policy that many would haveconsidered racist, had it been implemented

by the apartheid regime. The governmentinsists that the cost–benefit of providingARVs to HIV-positive pregnant womenshould be demonstrated before any changein policy is made. But critics argue thatthese government studies have already beendone and show that the expenses associatedwith the purchase of drugs, formula andclean water, and the need to care for theuninfected orphans, will be surpassed or atleast equalled by the costs of providingmedical treatment to the many thousandsof babies who will be born with preventableHIV disease. An estimated 600,000 HIV-infected infants are born worldwide eachyear, 60,000 of them in South Africa.

The biennial International Conferenceon AIDS gains more media coverage thanany other medical or scientific conference.The media barrage probably does more topromote HIV awareness and prevention

than the efforts of the scientists who presenttheir work at the meeting. We believe thatthe publicity surrounding the Durbanconference has the potential to translateinto millions fewer new cases of HIVinfection in developing countries.

Until now, South African governmentpolicy on ARVs has not received muchinternational media scrutiny. This willchange during the weeks before theconference. The government may find thata well-attended conference, with its mediapresence, creates more pressure to changepolicy on drugs for HIV-infected pregnantwomen than a boycott ever would have.Mark A. Wainberg(President)International AIDS Society,McGill University AIDS Centre, Jewish GeneralHospital, 3755 Chemin Côte-Ste-Catherine,Montreal, Quebec H3T 1E2, Canada

Say no to boycott of AIDS conference

Take the best from bothpatents systems

Sir — As a patent lawyer, I read with interestyour report on the European efforts topersuade the United States to switch to thefirst-to-file system for determining priorityon patentable inventions1. While the first-to-file system appears to be simpler, and thenorm outside the United States, it would bea mistake to abandon the American systembased on ‘first to invent’.

The apportionment of credit forinventions is not a mere intellectualconcern because bonuses and promotionsare often tied to productivity measured bypatentable research. But many researchersare unable to voice their claims at the timeof filing a patent because others areclaiming more credit than is due to them.Reasons for such reticence include jobinsecurity, change in employment,immigration concerns or just the ordinarypolitics that accompanies all humanactivities.

Unlike a scientific research paper, apatent issued in the United States can beinvalidated for improper naming ofinventors, as measured by the conception ofthe invention. This includes omission andimproper inclusion of inventors. Thus, theAmerican system provides true inventorswith a safeguard that can be invoked if theyprovide reasonable evidence of theiractivities. Correction of inventorship is acommon hurdle faced by European patentapplications filed in the United States,owing to lax standards in assigning credit

elsewhere. Interestingly, in the same issue ofNature Michael J. Larkin2 reports thatestablished UK molecular biologistspublished an average of only one paperevery 3.8 years in their early careers. The USsystem is not perfect but it does address aproblem that is mostly just debatedelsewhere.

A potential compromise would be tomeasure priority of the patent itself by thefirst-to-file system but also require thenaming of the inventors. Inventors wouldbe able to appeal if their names wereexcluded. This would retain the threat ofinvalidation of tainted patents whileincorporating the efficiencies of the first-to-file system.Rattan Nath1830 Euclid Avenue, Berwyn, Illinois 60402, USA1. Masood, E. Nature 397, 457 (1999).

2. Larkin, M. J. Nature 397, 467 (1999).

On the trail of theprolific Dr Path

Sir — While using an electronic abstractingservice I was surprised to see an additionalauthor on one paper. This author, D. Phil,had a good publication record in a varietyof fields — 76 papers over the past 18 years.

I also noted reasonable publication ratesin medical research for M. R. C. Path (48),B. Chir (31) and F. R. C. Path (22). ThePaths may be related as they have publishedjointly on four occasions. But F. R. C. Anaes(7), M. I. Biol (5) and C. Chem (4) do notseem to have been so productive.

Perhaps Janne Kotiaho’s concerns aboutmis-citation should not be limited toarticles originating in non-English speakingcountries (Nature 398, 19; 1999). Andperhaps citations should not be useduncritically for any serious purpose — atleast until abstracting services becomemore accurate, and discover the tradition,particularly in medical journals, of givingdegrees and professional qualifications afterauthors’ names.Nigel L. BrownSchool of Biological Sciences, University ofBirmingham, Edgbaston, Birmingham B15 2TT, UK

Going cold on ‘snowballEarth’ theory

Sir — Paul Hoffman and Adam Maloof1, indiscussing the paper by D. M. Williams etal.2, misconstrue the large-obliquityhypothesis for low-latitude glaciation nearsea level during the Proterozoic3 andoverlook relevant geological evidence.

Seasonality would be greatly amplifiedglobally with a large obliquity (¤54°). Thesolsticial climate would be severe in highlatitudes but more benign near the Equator,where mean annual insolation would beminimal and where substantial snowfallcould occur. The net accumulation ofsolsticial snow through successiveequinoxes, necessary for low-latitudeglaciation, would be aided by the highalbedo of snow and ice. Importantly,Neoproterozoic glaciogenic deposits inAustralia that formed near the palaeo-

© 1999 Macmillan Magazines Ltd

correspondence

556 NATURE | VOL 398 | 15 APRIL 1999 | www.nature.com

already used for crop production. Thereforeexpansion of agriculture to produce therequired organic nitrogen would necessitateuse of marginal land or furtherencroachment on natural ecosystems,resulting in soil degradation and loss ofbiological diversity.

Additionally, agronomic technology hasadvanced considerably beyond the‘conventional’ practices used by Drinkwateret al. In industrialized countries, themould-board plough has been largelyreplaced by no-till and conservation tillagepractices. Single applications of fertilizerare being replaced by multiple applicationswith amounts and timing matched to croprequirements. These practices result inimproved soil conservation and quality;greater efficiency in fertilizer use; higherand more stable yields; and they alsominimize the land area required for cropproduction.

Progress towards a ‘greener’ agriculturewill come from continued improvements inmodern high-yield crop-productionmethods combined with sophisticated useof both inorganic and organic nutrientsources, water, crop germplasm, pestmanagement and beneficial organisms.Thomas R. Sinclair*, Kenneth G. Cassman†*USDA-ARS, Agronomy Department, University ofFlorida, Gainesville, Florida 32611-0965, USA†Department of Agronomy, University of Nebraska,Lincoln, Nebraska 68583-0915, USA

1. Drinkwater, L. E. et al. Nature 396, 262–265 (1998).

2. Tilman, D. Nature 396, 211–212 (1998).

Green revolutionstill too green

Sir — L. E. Drinkwater et al.1 reportpromising isolated studies onenvironmental quality and productivity incrop production. But these studies shouldnot be used to discredit high-yield cropproduction technologies globally.

We do not dispute David Tilman’s call,in his News and Views article2

accompanying the paper by Drinkwater etal., for a greener agriculture based onecological principles. But we do not thinkthat as things stand we have the ability tocope with the probable doubling in globalfood demand in the twenty-first centurywith only organic nutrient inputs.

The organic nitrogen productionschemes investigated by Drinkwater et al.used essentially twice the land area of their‘conventional’ system to produce equivalentamounts of grain. But the best arable land is

Fertile grounds fora lively debate

Sir — I am not surprised that HermannBondi1 was puzzled by my correspondencewith Roger Short2,3, which concerned therelative importance of fertility andagriculture in the population explosion.

I myself was puzzled by Short’s response,because I was not arguing that fertility isinfluenced by nutrition; in fact I had beennaively unaware that this is the subject of alively controversy.

I simply meant that an increase infertility (from whatever cause) could not byitself have resulted in population growthbecause the additional babies would havestarved. Without the agricultural advancesof this century, the world population wouldnot now be approaching six billion, nomatter what the fertility rates were.Stephen G. WarrenDepartment of Atmospheric Sciences, University ofWashington, Seattle, Washington 98195-1640, USA

1. Bondi, H. Nature 397, 644 (1999).

2. Warren, S. G. Nature 397, 101 (1999).

3. Short, R. Nature 397, 101 (1999).

with limited long-term prospects. Thissituation is only alleviated by the benefactionof senior scientists and charitablefoundations, and occasional directives inselected areas which allow young scientists todevelop independent research.

Further obstacles exist in therecruitment process: new positions areoften focused on narrow research areas andonly advertised locally (in Danish). Recentwell-intentioned legislative changes havenot fully addressed these problems.

Such an inflexible system (which oftenobliges scientists to spend their entire careerin the same institute) is ill-equipped toadapt to the rapid development of newareas in basic research. The only surprise isthat Danish science has remained socompetitive for so long. How long this willcontinue to be the case is unclear whenthere is little to attract young scientists.Without a competitive basic researchcomponent, the ability to foster novelapplied research (so beloved of the presentgovernment) will be severely eroded.

Similar criticisms have been levelled atSweden. In its case at least some of thesecriticisms are now being taken to heart, ascan be seen by the establishment of openlycompetitive, well funded, junior facultypositions at the new Centre for MolecularMedicine in Umea. We hope that similarinitiatives will be taken in Denmark. Michael Ibba, Thomas BentinCentre for Biomolecular Recognition,Institute of Medical Biochemistry and Genetics,Panum Institute, Copenhagen University,2200 Copenhagen N, Denmark

1. May, R. M. Science 281, 49–51 (1998).

2. Horton, B. Nature 395, 412–413 (1998).

Denmark lacks coherentpolicy on basic research

Sir — Recent months have seen a lively,and at times bitter, debate in the Danishmedia on the future direction of scientificresearch. Much has been made by thegovernment of the need to shift towardsmore applied research to maximize theshort-term benefits of public investment.However, we would suggest that morecritical problems exist that must beaddressed immediately to ensure the long-term health of Danish science. Chiefamong these are a poorly funded andmisdirected policy on basic researchfunding, and conditions of employmentthat restrict the research opportunities ofyoung scientists.

Danish science is moderately wellfunded1. We have modern facilities, anexcellent level of technical support and abuoyant biotechnology sector2. What issorely lacking is a coherent policy on thefunding and nurturing of basic research.Entry-level appointments (assistantprofessor) have a heavy teaching load and nosupport for scientific staff. Young scientistscannot improve their situation by writinggrant applications, since the fundingavailable to the research councils allows little,if any, support for salary components. Suchrestrictions are making assistantprofessorships increasingly unattractive,

equator4 contain seasonal freeze-thawwedge structures in permafrost regolith thatindicate marked seasonal changes oftemperature3,4.

The ‘snowball Earth’ hypothesis for low-latitude glaciation5 is difficult to simulate6,7

and conflicts with geological evidence. Thelate Neoproterozoic stratigraphic record8

shows no sign of the drastic lowering of sealevel that would accompany globalglaciation. Moreover, seasonal freeze-thawstructures could not form near the Equatoron a snowball Earth because the very lowglobal temperatures would inhibit seasonalvariation9.George E. WilliamsDepartment of Geology and Geophysics,University of Adelaide, SA 5005, Australia

1. Hoffman, P. F. & Maloof, A. C. Nature 397, 384 (1999).

2. Williams, D. M. et al. Nature 396, 453–455 (1998).

3. Williams, G. E. Earth Sci. Rev. 34, 1–45 (1993).

4. Schmidt, P. W. & Williams, G. E. Earth Planet. Sci. Lett. 134,

107–124 (1995).

5. Hoffman, P. F. et al. Science 281, 1342–1346 (1998).

6. Crowley, T. J. & Baum, S. K. J. Geophys. Res. 98, 16723–16732

(1993).

7. Walsh, K. J. & Sellers, W. D. Global Planet. Change 8, 219–230

(1993).

8. Preiss, W. V. Geol. Surv. S. Aust. Bull. 53, 438 (1987).

9. Sellers, W. D. Palaeogeogr., Palaeoclimatol., Palaeoecol. 82,

217–224 (1990).