Note 3. on the origins of Greenie Politics. ----- Original Message ----- From: Science-Week <[EMAIL PROTECTED]> To: <[EMAIL PROTECTED]> Sent: Wednesday, July 19, 2000 6:32 AM Subject: ScienceWeek Shareware Edition - July 21, 2000 > > > > > -------------- Enclosure number 1 ---------------- > =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-= > This is the shareware abridged edition of SCIENCEWEEK. Upgrade to > the regular edition and receive it complete in your Email box > each week. By upgrading to the regular edition, you make possible > the continued existence of ScienceWeek as an important vehicle > for crossing barriers between the sciences. Upgrade information > is available at: http://www.scienceweek.com/subinfo.htm > or by Email at [EMAIL PROTECTED] > > PLEASE NOTE: You may freely distribute, retransmit, and post the > Shareware Edition of ScienceWeek provided it remains intact, > including front and back material, and with no editing of text. > =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-= > To subscribe to the Shareware Edition of ScienceWeek and receive > it free via Email, transmit "SUBSCRIBE SWX" to > [EMAIL PROTECTED] > > To unsubscribe, transmit "REMOVE SWX" to [EMAIL PROTECTED] > =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-= > > SCIENCE-WEEK (Shareware Edition) > > A Weekly Email Digest of the News of Science > > A journal devoted to the improvement of communication > between the scientific disciplines, and between scientists, > science educators, and science policy-makers. > > July 21, 2000 -- Vol. 4 Number 29 > > ----------------------------------------------- > > There is no national science just as there is > no national multiplication table; what is national > is no longer science. > -- Anton Chekhov (1860-1904) > > ----------------------------------------------- > > Contents of this Issue: > > 1. Evolutionary Biology: > Y Chromosome Evidence for an Early Common Human Ancestor > -------------------------------------------------------- > A new study of the ancestry of human Y chromosomes reveals that > the expected time to the most recent common ancestor of modern > humans is remarkably short, on the order of 50,000 years. > (Includes related background material.) > > 2. Medical Biology: > On the Immune System > -------------------- > Nowhere is the idea of the human body as a colony of cells more > clear than in consideration of the cooperative interactions of > the various cells of the immune system functioning to protect the > entire organism. (Includes related background material.) > ***In Regular Edition Only*** > > 3. Science Policy: > On the Irresponsibility of "Politically Responsible" Science > ------------------------------------------------------------ > The call for politically responsible science, frequently heard > today, cannot solve the problem of how scientists can prevent > science from serving immoral and inhuman ends. > (Includes related background material.) > > 4. Chemistry: > Development and Applications of a Self-Associating Protein > ---------------------------------------------------------- > A single point mutation in the ligand-binding site of a human > immunosuppressant-binding protein converts the normally monomeric > protein into a ligand-reversible dimer. > (Includes related background material.) > ***In Regular Edition Only*** > > 5. Chemistry: > Selection of Optical Isomers by an Applied Magnetic Field > --------------------------------------------------------- > Researchers report the first unequivocal use of a static magnetic > field to bias a chemical process in favor of one of left- or > right-handed enantiomers. (Includes related background material.) > ***In Regular Edition Only*** > > 6. Physics: > On the Nonessentiality of Theory in Physics > ------------------------------------------- > A theoretical physicist argues that theoretical physics is > usually irrelevant and often a hindrance to new experimental > breakthroughs. > > 7. In Brief: > Bohr, Heisenberg, and Copenhagen -- Again. > ***In Regular Edition Only*** > > 8. In Focus: On Conditioned Reflexes > > 9. From the SW Archive: > An Interesting Case of Ant-Plant Mutualism > ------------------------------------------ > An intriguing mutualism between plants and ants in which "guard- > ants" are apparently signaled by the plant to stop guarding > during plant pollination periods. > ***In Regular Edition Only*** > > =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-= > > 1. EVOLUTIONARY BIOLOGY: > Y CHROMOSOME EVIDENCE FOR AN EARLY COMMON HUMAN ANCESTOR > The main disciplines in the study of modern human origins > are human evolutionary genetics (especially evolutionary > molecular genetics), human paleontology (the study of human > fossils), archeology (especially the study of prehistoric human > cultures), and paleodemography (the study of prehistoric human > population distributions and migrations). Each discipline has its > own methods and specialist terminology, and there are areas of > both agreement and disagreement. The current consensus view > across all these disciplines is that modern humans originated in > Africa and spread to other continents, and that early modern > humans experienced an exponential population growth. Concerning > the time of the common origin of present humans, which is > presumed to be earlier than the emergence from Africa, the > estimates range from less than 50,000 years ago to approximately > 150,000 years ago, with evidence from molecular genetics pointing > to a more recent common origin, and evidence from paleontology > indicating a more remote common origin. > In this context, the term "polymorphism" refers to a > naturally occurring variation in the normal nucleotide sequence > of the genome within individuals in a population. Variations are > denoted as polymorphisms only if they cannot be accounted for by > recurrent mutation and occur with a frequency of at least about 1 > percent. > The term "recombination", in this context, refers to the > occurrence of progeny with combinations of genes other than those > that occurred in the parents, the occurrence due to independent > assortment or "*crossing over". > The Y chromosome is one of the two chromosomes that > determine sex in many animals, including humans, and it carries > mostly male-specific genes. > ... ... R. Thomson et al (5 authors at 3 installations, US UK) > present a study of the ancestry of human Y chromosomes, the > authors making the following points: > 1) During the past 10 years, DNA polymorphisms have been > widely used to reconstruct human evolutionary history. > *Mitochondrial DNA originally was used for this purpose, because > the high mutation rate of mitochondrial DNA produced numerous > polymorphisms and the absence of recombination facilitated their > interpretation. In male lineages, the Y chromosome shares some of > these properties, e.g., uniparental inheritance and absence of > recombination (in the nonrecombining part), but until recently, > studies of the Y chromosome have been hampered by the scarcity of > DNA sequence polymorphisms. > 2) The authors analyzed a data set of DNA sequence variation > at three Y chromosome genes (SMCY, DBY, DFFRY) in a worldwide > sample of human Y chromosomes. Between 53 and 70 chromosomes were > fully screened for sequence variation at each locus by a high- > performance liquid chromatography method. The sum of the lengths > of the 3 genes is 64,120 base pairs. The authors used these data > to study the ancestral genealogy of human Y chromosomes, with a > particular focus on estimating the expected time to the most > recent common ancestor and the expected ages of certain mutations > with interesting geographic distributions. > 3) The geographic variation distribution was found similar > to that obtained for other gene loci, but the expected time to > the most recent common ancestor is remarkably short, on the order > of 50,000 years. Thus, although previous studies have noted that > Y chromosome variation shows extreme geographic structure, the > authors suggest that the spread of Y chromosomes out of Africa is > much more recent than previously believed. The authors also > suggest that their data indicate substantial population growth in > the effective number of human Y chromosomes. > 4) Commenting on this work, Jaume Bertranpetit (Universitat > Pompeu Fabra Barcelona, ES) states as follows: "Inferences from > molecules to populations are not straightforward, and there have > been recurrent worries [about] what was being analyzed, either > the genes or genomic regions on one hand, or the individuals, > populations, or species on the other. There have been worries > concerning the accuracy of our knowledge of genome dynamics, > worries concerning the ability and power to detect specific > processes and disentangle cases where more than one mechanism may > have produced similar genetic patterns, and worries concerning > the appropriateness of evolutionary models needed for the > inference. And finally, there have been worries from > anthropologists who do not perceive the interface between the > evolutionary biology of a species and that of tiny fragments of > DNA, usually in noncoding regions, worries surrounding a fast- > developing field, heir to classical population genetics, with > brilliant novelties but also eager to get headlines." > ----------- > R. Thomson et al: Recent common ancestry of human Y chromosomes: > Evidence from DNA sequence data. > (Proc. Natl. Acad. Sci. US 20 Jun 00 97:7360) > QY: Marcus W. Feldman [[EMAIL PROTECTED]] > ----------- > Jaume Bertranpetit: Genome, diversity, and origins: The Y > chromosome as a storyteller. > (Proc. Natl. Acad. Sci. US 20 Jun 00 97:6927) > QY: Jaume Bertranpetit [[EMAIL PROTECTED]] > ----------- > Text Notes: > ... ... *crossing over: In general, the exchange of genetic > material between homologous chromosomes. > ... ... *Mitochondrial DNA: Mitochondria are double-membrane > enclosed organelles of cells, and they are involved in several > important biochemical pathways, including electron transport and > oxidative metabolism. Various types of eukaryotic cells (cells > containing membrane-bound organelles such as a nucleus) may > contain from a few to several thousand mitochondria in each > individual cell. The mitochondria are relatively large > cylindrical structures up to 10 microns long and up to 2 microns > in diameter, and they are believed to have originated as > organisms that became symbiotic with eukaryotic cells. (In > biology, "symbiosis" is an intimate and protracted association of > individuals of different species.) Mitochondria contain their own > genome, and mitochondrial DNA (denoted as mtDNA), found in the > mitochondria of all eukaryotes, is believed to evolve in parallel > with nuclear DNA, but since sperm mitochondria are apparently > quickly destroyed inside egg cells, mitochondrial DNA is > primarily inherited only in the maternal lineage in animals. > ------------------- > Summary & Notes by SCIENCE-WEEK http://scienceweek.com 21Jul00 > For more information: http://scienceweek.com/swfr.htm > ------------------- > Related Background: > ANTHROPOLOGY: GENOMIC ANALYSIS OF HUMAN HISTORY > An important new trend in recent years has been a merging of the > research interests of molecular geneticists, anthropologists, and > historians. New tools of genomic analysis are beginning to shed > light on historical questions such as migrations of ancient > peoples, differences in migration patterns of males and females, > historical demography of cultures with ancient roots, patterns of > human genetic diversity, and so on. It is apparent that in > certain areas of the study of history, historical analysis is > undergoing a methodological transformation. > ... ... K. Owens and M-C. King (University of Washington, US) > present a review of recent applications of genomic analysis to > history and anthropology, the authors making the following > points: > 1) Molecular genetics has begun to revolutionize the study > of human evolution. Analysis of human genomes now offers the > possibility of understanding movements and events of more recent > human history, and analysis of records written in human DNA can > complement historical analysis of records written by human > observers. > 2) Human migrations: Every present-day population retains > clues to its ancient roots, and common ancestries can be > confirmed and human migrations traced by comparing DNA > frequencies of present-day populations. Early migrations of > modern humans out of Africa have been traced by analysis of DNA > sequences; more recent human migrations have been followed > through genetic trails as well. An example is the application of > statistical analysis of classical *polymorphisms to the question > of ancient migrations within Europe. One important question > concerning migrations in general is whether males and females > migrate in the same ways. Genetic analysis of sequences of > *mitochondrial DNA (mtDNA) and *Y chromosome markers carried out > in the past few years suggest that the migration rates of males > and females have been dramatically different for much of human > history, with higher migration rates among females than among > males. When females relocate to the birthplaces of their spouses, > children are born close to the birthplaces of their fathers but > further from the birthplaces of their mothers. Most individual > females do not move far, but over hundreds of generations, the > genetic effects of their movements accumulate, leading to the > observed migration patterns. > 3) Genetic perspectives on cultural history: Genomic > analysis can reveal the historical demography of cultures with > ancient roots, and also indicate how current populations are > related to each other, including the extent and timing of their > contacts. An important historical question, for example, concerns > the movement of people and genes along ancient trade routes. The > Kazakh, Uighur, and Kirghiz populations of central Asia live > along the Silk Road, the trade route between Europe and Asia that > flourished between approximately 200 B.C. and 400 A.D. Analysis > of mitochondrial DNA sequences of these populations suggests that > they are descended from people moving from Europe to Asia and > vice versa more than 2000 years ago, albeit long after the early > human migrations out of Africa. Y chromosome variation in part > parallels language differences among these populations, whereas > mitochondrial DNA variation does not. Y chromosome data from > central Asia and from other regions of the world suggest that > genetic differences at linguistic boundaries are due primarily to > male rather than female isolation. Genetic evidence also supports > the oral tradition that the Lemba, who are now Bantu-speaking > people of southern Africa, derive from Jews who migrated from the > Middle East to Yemen 2700 years ago, and from Yemen to southern > Africa 2400 to 2000 years ago. More than 50 percent of Lemba Y > chromosomes carry *haplotypes that are common among Jewish > populations but absent in their African neighbors. > 5) Genetics, history, and race: Of importance is the fact > that genetic differences of populations from different continents > represent only approximately 10 percent of human genetic > diversity: no major genetic discontinuities across populations > have been observed. Most human genetic variation antedates the > migration of modern humans out of Africa. The possibility that > human history has been characterized by relatively homogeneous > genetic groups ("races"), distinguished by major biological > differences, is not consistent with genetic evidence. Variation > in traits, including skin color, popularly used to identify > "races", is likely due to straightforward mechanisms involving > limited numbers of genes with very specific physiological > effects. Of course prejudice does not require a rational basis, > let alone an evolutionary one, but the myth of major genetic > differences across "races" is nonetheless worth dismissing with > genetic evidence. > ----------- > K. Owens and M-C. King: Genomic views of human history. > (Science 15 Oct 99 286:451) > QY: Kelly Owens, Univ. of Washington Seattle 206-543-8992. > ----------- > Text Notes: > ... ... *polymorphisms: See main report. > ... ... *mitochondrial DNA (mtDNA): See main report. > ... ... *Y chromosome markers: See main report. > ... ... *haplotypes: (haploid genotypes) The term "haplotype" > refers to a particular combination of genes (specifically, > *alleles) in a defined region of a chromosome. > ... ... *alleles: (allelomorph) An "allele" is one of two or more > forms of a given gene that control a particular characteristic, > with the alternative forms occupying corresponding loci on > homologous chromosomes. Different alleles usually produce > different characteristics in an organism, e.g., brown versus blue > eyes. > ------------------- > Summary & Notes by SCIENCE-WEEK [http://scienceweek.com 7Jan00 > For more information: http://scienceweek.com/swfr.htm > ------------------- > Related Background: > PALEOLITHIC HUMAN POPULATION EXPANSION IN AFRICA > Human populations have undergone dramatic expansions in size, but > other than the growth associated with agriculture, the dates and > magnitudes of those expansions have never been resolved. Genetic > approaches to the study of human population expansions have > focused on variation at a single genetic locus, the "control > region" of *mitochondrial DNA. But in the study of demographic > history, single-locus investigations suffer from pronounced > statistical and biological limitations. The statistical problem > is that the conclusions rely on only one particular realization > of a gene genealogy, the "tree" determining the ancestral > relationships among a set of *alleles. The biological problem is > that there are a large number of functional genes in the > mitochondrion, and due to a complete linkage, a selective sweep > for any one of the genes may lead to a spurious signal of > expansion. ... ... Reich and Goldstein (University of Oxford, UK) > present two new statistical tests for population expansion, using > variation at a number of unlinked genetic markers to study the > demographic histories of natural populations. The authors report > that analysis of genetic variation in various aboriginal > populations throughout the world reveals highly significant > evidence for a major human population expansion in Africa, but no > evidence of expansion outside of Africa. The inferred African > expansion is estimated to have occurred between 49,000 and > 640,000 years ago, certainly before the Neolithic expansions, and > probably before the splitting of African and non-African > populations. The authors suggest that in showing a significant > difference between African and non-African populations, their > analysis supports the unique role of Africa in human evolutionary > history. The authors also suggest that the missing signal in non- > African populations may be the result of a population bottleneck > associated with the emergence of these populations from Africa, > as postulated in the "Out of Africa" model of modern human > origins. > QY: David B. Goldstein [[EMAIL PROTECTED]] > (Proc. Natl. Acad. Sci. US 7 Jul 98 95:8119) > (Science-Week 7 Aug 98) > ------------------- > Text Notes: > ... ... *mitochondrial DNA: See notes to previous report. > ... ... *alleles: See notes to previous report > ------------------- > Related Background: > GENETIC TRACES OF ANCIENT DEMOGRAPHY > The term "haploid loci" refers to genome locations that derive > from only one parent... A "nonrecombining" part of a genome is a > part that does not vary when the entire genome is replicated > during reproduction. The Pleistocene is the geological time > period from about 2 million years ago to about the end of the > last glaciation about 10,000 years ago. Modern man is believed > to have evolved during the Pleistocene. > ... ... Harpending et al (6 authors at 3 installations, US), in a > study of the demographic history of the human species as revealed > by patterns of gene differences, report that haploid loci like > mitochondrial DNA and the nonrecombining part of the Y chromosome > show a pattern indicating expansion from a population of only > several thousand during the late middle or early upper > Pleistocene. The authors suggest our ancestral population size > during nearly the whole Pleistocene was of the order of 10,000 > breeding individuals, and that genetic evidence denies any > version of the multiregional model of modern human origins, and > implies instead that our ancestors were effectively a separate > species for most of the Pleistocene, a small population probably > occupying an area the size of Swaziland or Rhode Island rather > than a whole continent. The authors further suggest that > archeologists should find and identify this population. > QY: Henry C. Harpending [[EMAIL PROTECTED]] > (Proc. Natl. Acad. Sci. US 17 Feb 98) (Science-Week 20 Mar 98) > ------------------- > Related Background: > Y CHROMOSOME EVIDENCE INDICATES AFRICAN ORIGINS OF MAN > The Y chromosome is one of the two chromosomes that determine sex > in many animals, including humans, and it carries mostly male- > specific genes. Genetic polymorphisms are individual functional > variations of specific genes or genetic markers that occur in a > population with a significant frequency, e.g., more than 1%. > ... ... At a recent symposium on human evolution (Cold Spring > Harbor Laboratory, NY US), a consensus was apparently reached > that current studies of human Y chromosome polymorphisms indicate > that the major human migrations that occurred had their source in > Africa, and that a small number of present African populations, > the Ethiopians, Sudanese, and south African Khoisans, possess > markers that have been conserved since that time. The data are > considered to confirm the recent mitochondrial DNA studies which > also indicate Africa as the source of human migrations. Some > paleoanthropologists are calling the Y chromosome results an > "unquestionable major breakthrough". > (Science 31 Oct 97) (Science-Week 21 Nov 97) > For more information: http://scienceweek.com/swfr.htm > > =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-= > > 2. MEDICAL BIOLOGY: > ON THE IMMUNE SYSTEM > ***In Regular Edition Only*** > > =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-= > > 3. SCIENCE POLICY: > ON THE IRRESPONSIBILITY OF "POLITICALLY RESPONSIBLE" SCIENCE > Since science, in the words of J.R. Oppenheimer (1904-1967) > brings "power over the world", and since politics is more or less > devoted to the wielding of such power, one can reasonably expect > an implicit or explicit bond between science and politics to > always pervade their respective histories. How is the individual > scientist to deal with this dangerous dance of science and > politics, which is more a passionate tango than a minuet? This > question is not easily answered. > ... ... Ute Deichmann (Institute for Genetics Cologne, DE), > presents an essay on the dangers of "politically responsible" > science, the author making the following points: > 1) Disillusionment concerning the contributions of eminent > scientists to the Nazi Regime (1933-1945) led many to question > the notion of a pure and universal science, to reject this as a > myth, and instead to redefine science as a socially organized > political enterprise. Proponents of this view argue that science > must be politically responsible, directed towards socially > acceptable goals, and assessed according to its long-range > consequences. > 2) But this call for politically responsible science does > not guarantee an ethical stance. For example, environmentalists > attempted in the 1980s to create a "political ecology", but the > intellectual origins of their criticisms of "causal reductionist" > science lie in the 1920s, when German ecologists proclaimed > ecology as a path to "a view of the world, in which everything is > related to everything else, everything directly or indirectly > affects everything else." The ecologist Karl Friederichs became a > leading Nazi ecologist, and he and his colleagues created and > spread the view of biology as an eminent political science aimed > at serving "the benefit of the people (Volk)" and of ecology as > the "doctrine of blood and soil". > 2) Eugenics, or race hygiene, is another example of > scientists claiming to act in a politically responsible manner, > with the idea that to avert long-range threats to the gene pool > it is necessary to institute compulsory sterilization of > "genetically unfit" people. These attempts to create a > politically responsible biology ended disastrously. The author > states: "If we criticize reductionist science for having > contributed to the technical and military power of the Nazis, we > have to acknowledge that 'politically responsible' biologists > provided for their ideological and political power." > 3) The author suggests there is a scientific level outside > politics, ethics, and applications. It is not the quest for > knowledge that was responsible for the Nazi atrocities, but the > fact that scientists did not pay due regard to normal ethical > principles. The author states: "Nazi moral standards were not > imposed on scientists. On the contrary, for whatever reason -- > opportunism, conviction, promotion, or power -- scientists lent > their support to ranking human beings as valuable, inferior or > worthless, hence providing the ideological basis of the Nazi > state." > 4) For example, Otmar von Verschuer, the director of the > Kaiser Wilhelm Institute for Anthropology, collaborated with > Josef Mengele in Auschwitz, and Verschauer's acceptance of organs > and blood from deliberately infected concentration-camp inmates > is considered by many as the most infamous crime in which > geneticists have participated, and a clear transgression of the > limits of science. > 5) The author concludes: "The example of Nazi Germany shows > that 'politically responsible' science endowed with power can > have disastrous consequences for innocent people and for science > itself. The call for politically responsible science, frequently > heard today, cannot solve the problem of how scientists can > prevent science from serving immoral, inhuman ends." > ----------- > Ute Deichmann: An unholy alliance. > (Nature 15 Jun 00 405:739) > QY: Ute Deichmann, Institute fur Genetik, Weyertal 121, D 50931, > Koln, DE. > ------------------- > Summary by SCIENCE-WEEK http://scienceweek.com 21Jul00 > For more information: http://scienceweek.com/swfr.htm > ------------------- > Related Background: > ON THE FIFTIETH ANNIVERSARY OF THE NUREMBERG CODE > This past August was the 50th anniversary of the formulation of > the Nuremberg Code, which occurred during the so-called Nazi > Doctors Trial held in Nuremberg DE immediately after the Second > World War, and which included 23 defendants, all but 3 of whom > were physicians accused of murder and torture in the conduct of > medical experiments on concentration camp inmates. Of the 23 > defendants, 16 were found guilty, and of the guilty 7 were > sentenced to death by hanging, 5 were sentenced to life > imprisonment, 2 to imprisonment for 25 years, 1 to imprisonment > for 15 years, 1 to imprisonment for 10 years. The executions were > carried out at the Landsberg prison, DE. In a recent review of > the Nuremberg Code, Evelyne Shuster (Veterans Affairs Medical > Center, Philadelphia US) describes the important role physicians > had in the prosecution of the Nazi doctors and in the formulation > of the Nuremberg Code, and she summarizes how medical researchers > have used the code over the past 5 decades. The author emphasizes > that perhaps the most important aspect of the code is the > centrality of informed consent of human subjects in experiments. > The editors of the journal in which the review appears have > recently criticized US research authorities for unethical > protocols in connection with HIV research in undeveloped > countries, protocols using placebo controls involving patients > with diagnosed medical conditions who could have been helped by > the drugs that were tested. > QY: E. Shuster, VA Medical Center, Philadelphia, PA 19104 US) > (New England J. Med. 13 Nov 97) (Science-Week 21 Nov 97) > For more information: http://scienceweek.com/swfr.htm > > =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-= > > 4. CHEMISTRY: > DEVELOPMENT AND APPLICATIONS OF A SELF-ASSOCIATING PROTEIN > ***In Regular Edition Only*** > > =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-= > > 5. CHEMISTRY: > SELECTION OF OPTICAL ISOMERS BY AN APPLIED MAGNETIC FIELD > ***In Regular Edition Only*** > > =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-= > > 6. PHYSICS: > ON THE NONESSENTIALITY OF THEORY IN PHYSICS > In modern physics, the historical roles of experiment and theory > and their interactions are often the focus of intense partisan > debate, so it is interesting to be confronted with the views of a > senior theoretical physicist who proposes that theory, despite > what most theorists proclaim, is far from the prime mover of > physics. > ... ... Harry J. Lipkin (Weizmann Institute of Science, IL) > presents a letter on the subject, the author making the following > points: > 1) The author suggests that real physics is an experimental > science that progresses from one experimental breakthrough to > another, and that in physics theorists are often irrelevant and > sometimes actually hinder progress by sitting on committees and > opposing the experiments that lead to new breakthroughs. > 2) The author suggests that the main breakthroughs in > physics since 1950 can be characterized as "who-ordered-that?" > effects, named after the famous remark by I.I. Rabi concerning > the discovery and existence of the particle that came to be > called the "*muon". The physics of the 1950s consisted of one > experimental discovery after another of who-ordered-that > particles, with no theoretical predictions beforehand and no > theoretical understanding afterward. By the 1960s, enough of such > particles had been discovered so that Murray Gell-Mann and Yuval > Ne'eman could arrange them in a table "without any understanding > of who ordered what." The subsequent Gell-Mann-Zweig *quark model > provided an explanation, but this model was strongly rejected by > members of a theoretical establishment, who were still fiddling > with irrelevancies. > 3) The next dramatic who-ordered-that experiment was > *charge-parity violation in 1965, which is still being debated by > theorists after 35 years. During this time, the theoretical > establishment was again confounded by the discovery of *scaling > in electron scattering, and a satisfactory after-the-fact > explanation by several young theorists was again resisted by the > theoretical establishment. > 4) In 1974, in what is sometimes called the "November > Revolution", the *J/psi particle was discovered by experiments > that theorists had insisted were completely useless and a waste > of valuable accelerator time and budget. "Of course, as soon as > the discovery was confirmed, a chorus of theorists claimed they > had predicted the existence of this hidden *charm particle." The > author states: "The November Revolution would have occurred > without theorists. It might even have occurred earlier if > theorists had not been around at accelerator program committees." > 5) The discovery of two kinds of *neutrinos was also > motivated not by theorists but by experimenters who noticed the > possibility of creating a neutrino beam in an accelerator, and > who actually did it -- without help from theorists. > 6) Eventually, after experimental data had been accumulated > so that the theorists could begin to make sense of them, the > *Standard Model came into existence. But the Standard Model did > not result from great theoretical or philosophical visions: it > arose from a succession of who-ordered-that and other pioneering > experiments that defied the theorists until there were enough > data to enable an after-the-fact analysis that would lead the > theorists in the right direction. > 7) The author states: "I have no patience with social > scientists, historians, and philosophers who insist that the > 'scientific method' is doing experiments to check somebody's > theory. The best physics I have known was done by experimenters > who ignored theorists completely and used their own intuitions to > explore new domains where no one had looked before. No theorists > had told them where and how to look." > 8) The author suggests that the important questions to be > asked by social scientists, historians, and philosophers concern > the experimenters in physics: What guides their explorations? How > do they choose where to look? How do they know when to persevere > despite continuous failure to find anything new? How do they know > when to drop an unproductive line and move on, rather than > obstinately pursue a dead end? > ----------- > Editor's note: As is evident, Lipkin's comments focus on the > history of particle physics during the past five decades. In > other areas of physics, the separate roles of theory and > experiment are perhaps less easy to assess. And in still other > areas of physics, where predictions associated with new > theoretical approaches have indeed produced new experimental > breakthroughs, the balance can be said to be on the other side. > In any case, it should be emphasized that Lipkin's main point is > not that theory in physics is useless, but that theory is not a > _necessary_ provocation for breakthrough experiments. Lipkin's > letter will no doubt produce rejoinders from theorists, more > thrust and parry in an ongoing debate. Meanwhile, nature knows > nothing of any disputes between theorists and experimenters, such > disputes remaining human secrets. > ----------- > Harry J. Lipkin: Who ordered theorists? > (Physics Today July 2000) > QY: Harry J. Lipkin [[EMAIL PROTECTED]] > ----------- > Text Notes: > ... ... *muon: A negatively charged particle with a mass > approximately 207 times that of the electron. The muon has a mean > lifetime of 2.2 microseconds, and decays into an electron, > *neutrino, and *antineutrino (see *neutrinos below). > ... ... *quark: See "charmed quark" below. > ... ... *charge-parity violation: (charge conjugation-parity > violation) Charge parity is a characteristic quantity > (eigenvalue) of a "charge conjugation operation", which in > general is an operation that changes every particle into its > antiparticle. In general, in such an operation, the laws of > motion are left unchanged (the principle of charge conjugation > conservation), but this principle is apparently violated by the > weak interactions. > ... ... *weak interactions: (weak forces) The weak force, one of > the four fundamental forces, occurs between leptons (particles > without internal structure, e.g., electrons, neutrinos) and > hadrons (particles with internal structure, e.g., neutrons and > protons); the weak force is responsible for radioactivity and for > the interconversion of neutrons and protons in stars. > ... ... *scaling in electron scattering: In this context, the > term "scaling" refers to a type of behavior occurring when high- > energy electrons are directed at protons to reveal the existence > of proton constituents. In this context, the term "scattering" > refers to the change in direction of a particle resulting from > collision with another particle. > ... ... *J/psi particle: (psi = psi meson) This particle was > discovered independently by Burton Richter and Sheldon Ting, and > they shared the Nobel Prize in Physics 1976 for their discovery. > The discovery of this particle, the main event in the "November > Revolution", electrified the physics community because it was > discovered apparently independently and simultaneously, and > because it was the first example of a particle formed from a > "*charmed quark", the quark whose existence had actually been > postulated by Sheldon Glashow 10 years earlier. > ... ... *charmed quark: A quark is a hypothetical fundamental > particle, having charges whose magnitudes are one-third or > two-thirds of the electron charge, and from which the elementary > particles may in theory be constructed. Along with fractional > electric charge, quarks also have "flavor" in 6 varieties (up, > down, charm, strange, top, and bottom), and "color" (red, yellow, > or blue). Thus, the "charmed quark" is one of the 6 known types > of quark. In the theory of quarks, "charm" is a *quantum number. > ... ... *quantum number: In quantum mechanics, certain properties > of a physical system often can take only discrete values (the > properties are "quantized"), and the various possible values are > called "quantum numbers". > ... ... *charm particle: (J/psi particle) See notes above. > ... ... *neutrinos: Neutrinos are fundamental particles with zero > charge, possibly zero mass, and an angular momentum factor (spin) > of 1/2. Various natural processes produce neutrinos: stellar > nuclear reactions, reactions occurring during supernova > explosions, cosmic ray collisions with matter, etc. > ... ... *Standard Model: In particle physics, the Standard Model > is a theoretical framework whose basic idea is that all the > visible matter in the universe can be described in terms of the > elementary particles *leptons and quarks and the forces acting > between them. > ... ... *leptons: A class of elementary particles. Although they > are affected by electromagnetic and gravitational forces, apart > from that they are involved only with weak interactions, acted > upon by weak forces but not by *strong forces, as opposed to > quarks, which are acted upon by strong forces but not by weak > forces. One further difference between leptons and quarks is that > leptons can be isolated as single particles, whereas quarks > apparently cannot. The leptons include the electron, the muon, > the tau, and their associated neutrinos. The mass of the tau is > approximately 3484 times the mass of the electron; the mass of > the muon is intermediate. > ... ... *strong forces: According to the Standard Model, the > fundamental forces comprise the gravitational force, the > electromagnetic force, the nuclear strong force, and the nuclear > weak force. The strong force is approximately 100 times stronger > than the electromagnetic interaction and in general is the force > responsible for the stability of the atomic nucleus. > ------------------- > Summary & Notes by SCIENCE-WEEK http://scienceweek.com 21Jul00 > For more information: http://scienceweek.com/swfr.htm > > =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-= > > 7. IN BRIEF: > BOHR, HEISENBERG, AND COPENHAGEN -- AGAIN. > ***In Regular Edition Only*** > > =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-= > > 8. IN FOCUS: ON CONDITIONED REFLEXES > "If food or some rejectable substance finds its way into the > mouth, a secretion of saliva is produced. The purpose of this > secretion is in the case of food to alter it chemically, in the > case of a rejectable substance to dilute and wash it out of the > mouth. This is an example of a reflex due to the physical and > chemical properties of a substance when it comes into contact > with the mucous membranes of the mouth and tongue. But, in > addition to this, a similar reflex secretion is evoked when these > substances are placed at a distance from the dog and the receptor > organs affected are only those of smell and sight. Even the > vessel from which the food has been given is sufficient to evoke > an alimentary reflex complete in all its details, and, further, > the secretion may be provoked even by the sight of the person who > brought the vessel, or by the sound of his footsteps. All these > innumerable stimuli falling upon the several finely > discriminating distance receptors lose their power forever as > soon as the [cerebral] hemispheres are taken from the animal, and > only those which have a direct effect on the mouth and tongue > still retain their power. The great advantage to the organism of > a capacity to react to the former stimuli is evident, for it is > in virtue of their action that food finding its way into the > mouth immediately encounters plenty of moistening saliva, and > rejectable substances, often nocuous to the mucous membrane, find > a layer of protective saliva already in the mouth, which rapidly > dilutes and washes them out. Even greater is their importance > when they evoke the motor component of the complex reflex of > nutrition, i.e., when they act as stimuli to the reflex of > seeking food." > ----------- > I.P. Pavlov: _Conditioned Reflexes: An Investigation of the > Physiological Activity of the Cerebral Cortex_ > (Foreign Languages Publishing House, Moscow 1924) > ----------- > Ivan Petrovich Pavlov (1849-1936) received the Nobel Prize in > Physiology and Medicine in 1904 for his work on conditioned > reflexes. The classical Pavlovian reflex involves a previously > neutral stimulus (e.g., the sound of a bell) becoming a > "conditioned stimulus" when presented together with an > "unconditioned stimulus" (e.g., food). As an unconditioned > stimulus, food produces a reflex secretion of saliva. After > conditioning, the conditioned stimulus (e.g., the sound of the > bell) elicits the physiological response (e.g., secretion of > saliva) previously elicited only by the unconditioned stimulus. > The secretion of saliva following the sound of the bell is then > called a "conditioned reflex". A complete understanding of the > neural interconnections and dynamics of such a simple > experimental situation is still one of the central problems of > neurobiology. > ------------------- > SCIENCE-WEEK http://scienceweek.com 21Jul00 > > =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-= > > 9. FROM THE SW ARCHIVE: > AN INTERESTING CASE OF ANT-PLANT MUTUALISM > ***In Regular Edition Only*** > > =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-= > > NOTICES > =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-= > This shareware edition of ScienceWeek contains complete reports, > but it does not contain all the reports present in the regular > edition. Subscription to the shareware edition of SW is free. > An upgrade to the regular edition of ScienceWeek is available for > $20 a year (2 yrs/$36, 3 yrs/$45). Regular edition subscriptions > are available at: www.scienceweek.com/subinfo.htm > > If you are not already a subscriber, and you wish to subscribe to > the ScienceWeek shareware edition, transmit "SUBSCRIBE SWX" to: > [EMAIL PROTECTED] > > To be removed from the SW shareware edition subscription list, > transmit "REMOVE SWX" to [EMAIL PROTECTED] > > Please note: The purpose of the shareware edition of ScienceWeek > is to provide an evaluation edition of the publication. The > regular edition of ScienceWeek carries no advertising and is made > possible only by the payments of its subscribers. > > Queries concerning subscriptions to: [EMAIL PROTECTED] > =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-= > > The first issue of SCIENCE-WEEK appeared May 1, 1997, and it has > been published regularly each week since that date. SW is > designed to cross existing conceptual and linguistic barriers > between the scientific disciplines. In general, the biology is > written for physicists and chemists, and the physics and > chemistry are written for biologists, with an attempt to retain > some exactitude in the particular science involved in the news. > These are the aims. Undoubtedly, we are not always successful, > and for that we apologize. In any case, what we hope is that our > readers are reading out of their fields more than in their > fields, since that is the essence of this publication. > > Editor/Publisher: Dan Agin [EMAIL PROTECTED] > Managing Editor: Claire Haller [EMAIL PROTECTED] > Associate Editor: Joan Oliner [EMAIL PROTECTED] > > Copyright (c) 1997-2000 SCIENCE-WEEK/Spectrum Press Inc. > All Rights Reserved > > --------------------------------------------- > This publication is protected by U.S. and International Copyright > Laws. The free shareware edition may be copied, retransmitted, > and distributed only as a complete intact text containing both > front and back material. Changes in the text are prohibited > without explicit permission from the publisher. SCIENCE-WEEK is > published by Spectrum Press Inc., 3023 N. Clark Street #109, > Chicago, 60657-5205 IL, USA. > --------------------------------------------- > -----end file
