Showing papers in "Science in 1964"
TL;DR: Weinberg as mentioned in this paper pointed out that some fields of science are moving forward very much faster than others, perhaps by an order of magnitude, if numbers could be put on such estimates.
Abstract: Scientists these days tend to keep up a polite fiction that all science is equal. Except for the work of the misguided opponent whose arguments we happen to be refuting at the time, we speak as though every scientist's field and methods of study are as good as every other scientist's, and perhaps a little better. This keeps us all cordial when it comes to recommending each other for government grants. But I think anyone who looks at the matter closely will agree that some fields of science are moving forward very much faster than others, perhaps by an order of mag nitude, if numbers could be put on such estimates. The discoveries leap from the head lines - and they are real advances in complex and difficult subjects, like molecular biology and high-energy physics. As Alvin Weinberg (1964), says "Hardly a month goes by without a stunning success in molecular biology being reported in the Proceed ing of the National Academy of Science." Why should there be such rapid advances in some fields and not in others? I think the usual explanations that we tend to think of-such as the tractability of the subject, or the quality or education of the men drawn into it, or the size of research contracts are important but inadequate. I have begun to believe that the primary factor in scienSource: Science (1965), 146:347-353. Copyright 1965 by the American Association for the Advancement of Science and reprinted by permission.
2,163 citations
TL;DR: Evidence can be obtained which suggests that mating may be followed by segregation in mice, and when two clonal lines of mouse fibroblasts are grown together for 4 days, hybrid cells can be detected by selective conditions.
Abstract: When two clonal lines of mouse fibroblasts, each containing a drug-resistant marker, are grown together for 4 days, hybrid cells can be detected by selective conditions. These hybrid cells are presumed to be the result of mating. By the same method evidence can be obtained which suggests that mating may be followed by segregation.
1,899 citations
1,246 citations
TL;DR: Property of the codeword recognition process and the minimum oligonucleotide chain length required to induce such interactions are presented, and the modification of RNA and DNA codewords, converting sense into missense or nonsense codewording, is suggested as a possible regulatory mechanism in protein synthesis.
Abstract: A rapid, sensitive method is described for measuring C14-aminoacyl-sRNA interactions with ribosomes which are specifically induced by the appropriate RNA codewords prior to peptide-bond formation. Properties of the codeword recognition process and the minimum oligonucleotide chain length required to induce such interactions are presented. The trinucleotides, pUpUpU, pApApA, and pCpCpC, but not dinucleotides, specifically direct the binding to ribosomes of phenylalanine-, lysine-, and proline-sRNA, respectively. Since 59-terminal, 39-terminal, and internal codewords differ in chemical structure, three corresponding classes of codewords are proposed. The recognition of each class in this system is described. The template efficiency of trinucleotide codewords is modified greatly by terminal phosphate. Triplets with 59-terminal phosphate are more active as templates than triplets without terminal phosphate. Triplets with 39- or 39 (29)-terminal phosphate are markedly less active as templates. These findings are discussed in relation to the probable functions of terminal codewords. The modification of RNA and DNA codewords, converting sense into missense or nonsense codewords, is suggested as a possible regulatory mechanism in protein synthesis.
1,237 citations
TL;DR: A simple waterfall sequence is proposed to explain the function of the various protein clotting factors during the formation of the fibrin clot.
Abstract: A simple waterfall sequence is proposed to explain the function of the various protein clotting factors during the formation of the fibrin clot. When clotting is initiated, each cloting factor except fibrinogen is converted to a form that has enzymatic activity. This activation occurs in a sepwise sequence with each newly formed enzyme reacting with its specific substrate, converting it to an active enzyme.
1,068 citations
TL;DR: It is shown that the endosperms of maize seeds homozygous for the opaque-2 mutant gene have a higher lysine content than normal kernels and the synthesis of proteins with a greater content of basic amino acids in the acid-soluble fraction of the mutant endosperm.
Abstract: Preliminary tests have shown that the endosperms of maize seeds homozygous for the opaque-2 mutant gene have a higher lysine content than normal kernels. As a critical test, a backcross progeny was divided into opaque-2 and normal kernels, the endosperms separated, and the amino acids determined. The opaque-2 endosperms had a different amino acid pattern and 69 percent more lysine than the normal seeds. The major reason for these changes is the synthesis of proteins with a greater content of basic amino acids in the acid-soluble fraction of the mutant endosperm. This is accompanied by a reduction in the ratio of zein to glutelin.
1,031 citations
TL;DR: Changes in pupil size during the solving of simple multiplication problems can be used as a direct measure of mental activity and shows that mental activity is closely correlated with problem difficulty, and that the size of the pupil increases with the difficulty of the problem.
Abstract: Changes in pupil size during the solving of simple multiplication problems can be used as a direct measure of mental activity. The pupil response not only indicates mental activity in itself but shows that mental activity is closely correlated with problem difficulty, and that the size of the pupil increases with the difficulty of the problem. These findings relate to recent Russian research on the pupillary reflex in connection with orienting and brain stimulation.
993 citations
TL;DR: Antibodies to bradykinin and angiotensin have been produced in rabbits by the use of conjugates containing albumin and the hapten, covalently bound using water-soluble carbodiimide reagents.
Abstract: Antibodies to bradykinin and angiotensin have been produced in rabbits by the use of conjugates containing albumin and the hapten, covalently bound. The use of water-soluble carbodiimide reagents provided an easy and rapid method of synthesis of the antigenic conjugates.
801 citations
TL;DR: A complex visual pattern presented for ten successive 1-minute exposure periods was fixated progressively less than comparable novel stimuli by infants 2 to 6 months old, suggesting that familiarization with the environment begins through visual exploration before more active exploration is possible.
Abstract: A complex visual pattern presented for ten successive 1-minute exposure periods was fixated progressively less than comparable novel stimuli by infants 2 to 6 months old. This indicates the occurrence of recognition and habituation of visual responsiveness to specific patterns, and suggests that familiarization with the environment begins through visual exploration before more active exploration is possible.
801 citations
TL;DR: I-Adamantanamine (amantadine) causes a selective, reproducible, dose-related inhibition of influenza infections in tissue culture, chick embryos, and mice and survivors are immune to a challenge infection with the original infecting virus.
Abstract: I-Adamantanamine (amantadine) causes a selective, reproducible, dose-related inhibition of influenza infections in tissue culture, chick embryos, and mice. The compound is not virucidal and appears to act by interfering with the penetration of the host cell by the virus. In influenza infections of mice, greatest efficacy occurs with treatment at the time of infection; however, there is significant antiviral activity with treatment delayed up to 72 hours after infection. Virus inhibition is not complete and survivors are immune to a challenge infection with the original infecting virus.
746 citations
TL;DR: Rearing complexity affects branching of dendrites in the visual cortex of the rat and the effects of environmental complexity and training on brain chemistry and anatomy are studied.
Abstract: JOURNAL OF NEUROPSYCHIATRY 459 Journal of Comparative and Physiological Psychology 1956; 82:261268 9. Rosen.zweig MR, Krech D, Bennett EL: Heredity, environment, brain biochemistry, and learning, in Current Trends in Psychological Theory. Pittsburgh, PA, University of Pittsburgh Press, 1961, pp 87-110 10. Rosen.zweig MR, Krech D, Bennett EL, Diamond MC: Effects of environmental complexity and training on brain chemistry and anatomy: a replication and extension. Journal of Comparative and Physiological Psychology 1962; 55:429-437 11. Volkmar FR, Creenough WT: Rearing complexity affects branching of dendrites in the visual cortex of the rat. Science 1972; 176:14451447 12. Bailey CH, Kandel ER: Structural changes accompanying memory storage. Annu Rev Physiol 1993; 55:397-426
TL;DR: The results reveal that vision is strongly dominant, often without the observer's being aware of a conflict.
Abstract: Observers were presented with an object whose visual shape, because of optical distortion, differed considerably from its tactual shape. After simultaneously grasping and viewing the object, the observers were required to indicate their impression of it by drawing it or by matching another object to it. The results reveal that vision is strongly dominant, often without the observer's being aware of a conflict.
TL;DR: Quaking is a new autosomal recessive mutant mouse with marked tremor of the hindquarters and Jimpy, a known sex-linked mutation, has similar but more severe symptoms and similar pathology, with the additional feature of sudanophilic (nonpolar) lipid distributed in some white-matter tracts.
Abstract: Two mutant mice with deficient myelination are described. Quaking is a new autosomal recessive mutant mouse with marked tremor of the hindquarters. The mice eat, swim, breed, and nurse well even though the entire central nervous system is very deficient in myelin by histological and chemical criteria. Myelin formation is impaired; no destruction is seen. Peripheral nerves are myelinated. Jimpy, a known sex-linked mutation, has similar but more severe symptoms and similar pathology, with the additional feature of sudanophilic (nonpolar) lipid distributed in some white-matter tracts. Both mutants offer new opportunities for study of the formation and functions of myelin.
TL;DR: In this article, the activation and cross-linking reactions of mitomycins and porfiromycin are discussed in terms of reactive sites on the mitomycin and DNA molecules.
Abstract: Mitomycins and porfiromycin, generally nonreactive in the natural oxidized state, behave as bifunctional "alkylating" agents upon chemical or enzymatic reduction, followed by spontaneous loss of the tertiary methoxy (hydroxyl) group and formation of an aromatic indole system. Thus activated, mitomycins and porfiromycin react in vitro with purified DNA, linking its complementary strands. A high content of guanine and cytosine favors this cross-linking reaction, which is the basis of the lethal effect in vivo of these antibiotics. The activation and cross-linking reactions are discussed in terms of reactive sites on the mitomycin and DNA molecules.
TL;DR: Male white-crowned sparrows have song "dialects," acquired in about the first 100 days of life by learning from older males, and in the laboratory an alien white-Crowning sparrow dialect can be taught.
Abstract: Male white-crowned sparrows have song "dialects," acquired in about the first 100 days of life by learning from older males. In the laboratory an alien white-crowned sparrow dialect can be taught. Once the song is established further acoustical experience does not change the pattern. White-crowned sparrows do not copy recorded songs of other sparrow species presented under similar conditions.
TL;DR: Find the secret to improve the quality of life by reading this transforming traditional agriculture, which can be your favorite book to read after having this book.
Abstract: Find the secret to improve the quality of life by reading this transforming traditional agriculture. This is a kind of book that you need now. Besides, it can be your favorite book to read after having this book. Do you ask why? Well, this is a book that has different characteristic with others. You may not need to know who the author is, how well-known the work is. As wise word, never judge the words from who speaks, but make the words as your good value to your life.
TL;DR: Pigeons were trained to respond to the presence or absence of human beings in photographs and their performances suggest greater powers of conceptualization than are ordinarily attributed to animals.
Abstract: Pigeons were trained to respond to the presence or absence of human beings in photographs. The precision of their performances and the ease with which the training was accomplished suggest greater powers of conceptualization than are ordinarily attributed to animals.
TL;DR: The effects of various neutral salts on the temperature of the thermally-induced denaturation of the globular protein ribonuclease are described and compared with the effects of these salts on helix-coil transition temperatures in other macromolecules.
Abstract: The effects of various neutral salts on the temperature of the thermally-induced denaturation of the globular protein ribonuclease are described and compared with the effects of these salts on helix-coil transition temperatures in other macromolecules. These agents affect the stability of the native form of macromolecules as diverse as ribonuclease, collagen, DNA, and myosin in very similar ways; salts such as KSCN and CaCl(2) serve as very potent general structural destabilizers or denaturants, while salts such as (NH(4))(2)SO(4) and K(2)HPO(4) strongly stabilize the native conformation. The effectiveness of the neutral salts as ribonuclease destabilizers is compared with that of urea and the guanidinium salts.
TL;DR: A deficiency, or absence, of cystathionine synthetase activity has been demonstrated in liver obtained from a mentally retarded child with homocystinuria.
Abstract: A deficiency, or absence, of cystathionine synthetase activity has been demonstrated in liver obtained from a mentally retarded child with homocystinuria.
TL;DR: Lymphocytes from two unrelated individuals, cultured together in the same tube, undergo morphological transformation to large cells and divide and the degree of cross-reactivity of grafts from the two individuals placed on a third unrelated recipient is correlated.
Abstract: Lymphocytes from two unrelated individuals, cultured together in the same tube, undergo morphological transformation to large cells and divide. Both of these parameters may be estimated quantitatively. There is a correlation between the degree of this response and the degree of cross-reactivity of grafts from the two individuals placed on a third unrelated recipient.
TL;DR: It was shown that depth can be perceived in the absence of monocular depth and familiarity cues and of all binocular depth cues except for disparity, and it has been demonstrated that the perception of ambiguous depth organizations can be influenced, even subliminally, by a preceding unambiguous stimulus.
Abstract: The reported phenomena were obtained through the use of special techniques. (i) All monocular depth and familiarity cues were removed from the stimuli (through the use of randomdot stereo patterns). (ii) The statistical and topological properties of the stimuli were precisely known (since they were generated according to a specific computer program). (iii) Convergence motions of the eye and proprioceptive cues were eliminated (through the use of tachistoscopic illumination). (iv) The time of presentation was under control (through erasure of the persistent afterimages). Under these conditions stereopsis could be studied in its purest form. It was shown that depth can be perceived in the absence of monocular depth and familiarity cues and of all binocular depth cues except for disparity. These findings have important implications for some existing theories of stereopsis and open up areas for further research. Some phenomena based on stereo erasure are reported here for the first time. It has been demonstrated that the perception of ambiguous depth organizations can be influenced, even subliminally, by a preceding unambiguous stimulus. Perhaps the most interesting result is the finding that the correspondence of objects and patterns in the two retinal projections can be established without actual recognition of the objects and patterns. This pattern matching is based on some relatively simple processes of finding connected clusters formed by adjacent points of similar brightness, and the processes seem to be amenable to rigorous analysis.
TL;DR: "Excess lactate," an indicator of oxygen debt, has been studied as a metabolic index of severity of the shock state in human patients and serves as an objective clinical guide for measurement of "reversibility".
Abstract: "Excess lactate," an indicator of oxygen debt, has been studied as a metabolic index of severity of the shock state in human patients. The levels of excess lactate correspond to severity of circulatory failure, and an excess of more than 4 millimoles per liter prognosticates a fatal outcome. The validity of this index was confirmed by studies on experimental hemorrhagic shock in dogs. It provides a parameter for measurement of "reversibility" and serves as an objective clinical guide.
TL;DR: Hydxyurea, hydroxyurethane, and dihydroxyurea inhibit incorporation of thymidine into the DNA of monolayers of HeLa cells, but hydroxylamine inhibits cellular incorporation of all three precursors:Thymidine, uridine, and leucine.
Abstract: Hydroxyurea, hydroxyurethane, and dihydroxyurea inhibit incorporation of thymidine into the DNA of monolayers of HeLa cells. They do not affect incorporation of uridine into RNA or of leucine into protein. In contrast, hydroxylamine inhibits cellular incorporation of all three precursors: thymidine, uridine, and leucine. Hydroxyurea does not affect thymidine kinase, thymidylate kinase, or DNA polymerase reactions, but it does inhibit incorporation of cytidylic and guanylic acids into DNA in cell-free supernatants.
TL;DR: The commonly held belief, for which there has previously been no direct and unequivocal evidence, that color vision is mediated by several kinds of receptors (possibly three), each containing photopigments absorbing in diflerent regions of the spectrum, is confirmed.
Abstract: Single parafoveal cones from human and monkey retinas were examined in a recording microspectrophotometer. Three types of receptors with maximum absorption in the yellow, green, and violet regions of the spectruin were found. Thus the commonly held belief, for which there has previously been no direct and unequivocal evidence, that color vision is mediated by several kinds of receptors (possibly three), each containing photopigments absorbing in diflerent regions of the spectrum, is confirmed.
TL;DR: Cyclo heximide and acetoxy-cycloheximide specifically inhibit protein synthesis in L-cells growing in suspension culture and in extracts of rat liver, the drugs inhibit transfer of amino acid from soluble RNA to polypeptide.
Abstract: Cycloheximide and acetoxy-cycloheximide specifically inhibit protein synthesis in L-cells growing in suspension culture. In extracts of rat liver, the drugs inhibit transfer of amino acid from soluble RNA to polypeptide. Unlike puromycin, these drugs do not accelerate release of nascent polypeptide chains. The drugs have no effect on protein synthesis in extracts of Escherichia coli.
TL;DR: Difference spectra of the visual pigments have been measured in single rods and cones of a parafoveal region of the human retina, presumably samples of the three types of cone responsible for human color vision.
Abstract: Difference spectra of the visual pigments have been measured in single rods and cones of a parafoveal region of the human retina. Rods display an absorption maximum (lambdamax) at about 505 mmicro associated with rhodopsin. Three kinds of cones were measured: a blue-sensitive cone with Amaxe about 450 mpf; two green-sensitive cones with Xmaa about 525 mumicro; and a red-sensitive cone with lambdamax about 555 mmicro These are presumably samples of the three types of cone responsible for human color vision.
TL;DR: C Citation Indexing Services Recently Bennett (47) has reiterated my earlier recommendation that an index to the abstracts in specialty journals and to abstracts prepared by the smaller abstracting services be compiled.
Abstract: ing Services Recently Bennett (47) has reiterated my earlier recommendation that an index to the abstracts in specialty journals and to abstracts prepared by the smaller abstracting services be compiled (21). Frequently these are abstracts which include criticism. As such, they constitute original publications. Every author should know of such critical abstracts of his papers. In literature searches, abstracts may serve in lieu of the original articles, particularly when the original article is in a foreign language, or when it is not readily available. Citation indexes can be used to locate these abstracts quickly and to identify unabstracted articles (31). Author Citation Index A random-access computer memory does not require special ordering for data storage. In such memories the arbitrarily assigned data-addresses need not be known to the user. By contrast, a printed citation index must have a
TL;DR: Computer-averaged potentials evoked from the cortex were recorded to nonsignal stimuli and to randomly interspersed signal stimuli requiring detection and response during prolonged visual vigilance as detection efficiency diminished over time.
Abstract: Computer-averaged potentials evoked from the cortex were recorded to nonsignal stimuli and to randomly interspersed signal stimuli requiring detection and response during prolonged visual vigilance. As detection efficiency diminished over time, the amplitude of evoked responses to nonsignal stimuli decreased and latency increased. Fluctuations in vigilance (attentiveness) during the course of the task also were accompanied by corresponding changes in evoked-potentials to nonsignal stimuli. More specific lapses of attention, revealed by detection failures, resulted in average evoked-responses of lower amplitude to missed as compared with detected signals.