Abstract:
:Mach bands, the illusory brightness maxima and minima perceived at the initiation and termination of luminance gradients, respectively, are generally considered a direct perceptual manifestation of lateral inhibitory interactions among retinal or other lower order visual neurons. Here we examine an alternative explanation, namely that Mach bands arise as a consequence of real-world luminance gradients. In this first of two companion papers, we analyze the natural sources of luminance gradients, demonstrating that real-world gradients arising from curved surfaces are ordinarily adorned by photometric highlights and lowlights in the position of the illusory bands. The prevalence of such gradients provides an empirical basis for the generation of this perceptual phenomenon.
journal_name
Proc Natl Acad Sci U S Aauthors
Lotto RB,Williams SM,Purves Ddoi
10.1073/pnas.96.9.5239keywords:
subject
Has Abstractpub_date
1999-04-27 00:00:00pages
5239-44issue
9eissn
0027-8424issn
1091-6490journal_volume
96pub_type
杂志文章abstract::A large number of primary petite (rho-) clones were isolated after ethidium bromide mutagenesis of various grande (rho+) strains of S. cerevisiae that contained the mitochondrial genetic markers, CR, ER, OIR (or OIIR), and PR. From the frequency of coretention of markers in the petites, we have deduced a probable circ...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.73.12.4608
更新日期:1976-12-01 00:00:00
abstract::We have combined standard micrococcal nuclease (MNase) digestion of nuclei with a modified protocol for constructing paired-end DNA sequencing libraries to map both nucleosomes and subnucleosome-sized particles at single base-pair resolution throughout the budding yeast genome. We found that partially unwrapped nucleo...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.1110731108
更新日期:2011-11-08 00:00:00
abstract::A short, highly stereoselective (over 97%) synthesis of all-trans squalene is described. Starting with succinaldehyde, a tetraenedichlorodione having the complete squalene skeleton with the four internal trans olefinic bonds has been developed in four steps involving a sequence of two double Claisen rearrangements. Th...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.67.3.1465
更新日期:1970-11-01 00:00:00
abstract::Recent research on rainforest speciation has highlighted the importance of habitat variation in generating population diversification but lacks evidence of an associated reduction in gene flow. This paper describes a study in which molecular markers were used to examine the effects of allopatric divergence and habitat...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.212248499
更新日期:2002-10-15 00:00:00
abstract::Most teenage fears subside with age, a change that may reflect brain maturation in the service of refined fear learning. Whereas adults clearly demarcate safe situations from real dangers, attenuating fear to the former but not the latter, adolescents' immaturity in prefrontal cortex function may limit their ability t...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.1005494108
更新日期:2011-03-15 00:00:00
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journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.1711631114
更新日期:2017-09-12 00:00:00
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journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.0501747102
更新日期:2005-09-13 00:00:00
abstract::The main sources of information regarding ancient Mesopotamian history and culture are clay cuneiform tablets. Many of these tablets are damaged, leading to missing information. Currently, the missing text is manually reconstructed by experts. We investigate the possibility of assisting scholars, by modeling the langu...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
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更新日期:2020-09-15 00:00:00
abstract::Cell membrane contact induces the de novo expression of choline O-acetyltransferase (CAT; acetyl-CoA: choline O-acetyltransferase, EC 2.3.1.6) activity in cultures of virtually pure neonatal rat dissociated sympathetic neurons. To identify molecular mechanisms underlying membrane-associated CAT induction, the responsi...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.86.3.1080
更新日期:1989-02-01 00:00:00
abstract::FIP-3 (14.7K interacting protein) was discovered during a search for cell proteins that could interact with an adenovirus protein (Ad E3-14.7K) that had been shown to prevent tumor necrosis factor (TNF)-alpha-induced cytolysis. FIP-3, which contains leucine zippers and a zinc finger domain, inhibits both basal and ind...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.96.3.1042
更新日期:1999-02-02 00:00:00
abstract::Acetyl-CoA carboxylase 1 (ACC1) catalyzes the formation of malonyl-CoA, the C2 donor for de novo synthesis of long-chain fatty acids. We have identified 64 exons, including 7 alternatively spliced minor exons (1A, 1B, 1C, 3, 5A', 5A, and 5B) in human ACC1 gene ( approximately 330 kb). The gene is regulated by three pr...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.1332670100
更新日期:2003-06-24 00:00:00
abstract::The T lineage repertoire is shaped by T cell receptor (TCR)-dependent positive and negative thymic selection processes. Using TCR-transgenic (N15tg) beta2-microglobulin-deficient (beta2m-/-) RAG-2(-/-) H-2(b) mice specific for the VSV8 (RGYVYQGL) octapeptide bound to Kb, we identified a single weak agonist peptide var...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.95.17.10061
更新日期:1998-08-18 00:00:00
abstract::Dimerization of human immunodeficiency virus type 1 protease (HIV-1 PR) monomers is an essential prerequisite for viral proteolytic activity and the subsequent generation of infectious virus particles. Disruption of the dimer interface inhibits this activity as does formation of heterodimers between wild-type and defe...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.93.21.11477
更新日期:1996-10-15 00:00:00
abstract::Periodical cicadas are well known for their prime-numbered life cycles (17 and 13 years) and their mass periodical emergences. The origination and persistence of prime-numbered cycles are explained by the hybridization hypothesis on the basis of their lower likelihood of hybridization with other cycles. Recently, we s...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.0900215106
更新日期:2009-06-02 00:00:00
abstract::T cells are activated physiologically by triggering the T-cell receptor-CD3 complex. There is evidence that invariant accessory molecules on the T-cell membrane (CD8 and CD4) are involved in the major histocompatibility complex-restricted recognition process. Moreover, binding and crosslinking of these accessory molec...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.85.24.9689
更新日期:1988-12-01 00:00:00
abstract::Inhibin, a gonadal hormone capable of preferential suppression of pituitary follicle-stimulating hormone (FSH) secretion, has recently been purified. The major form of this protein is an alpha beta heterodimer encoded by two separate genes. In contrast to the FSH-suppressing action of the alpha beta heterodimer, the b...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.84.14.5082
更新日期:1987-07-01 00:00:00
abstract::There is currently an unmet need for versatile techniques to monitor the assembly and dynamics of ternary complexes in live cells. Here we describe bioluminescence resonance energy transfer with fluorescence enhancement by combined transfer (BRETFect), a high-throughput technique that enables robust spectrometric dete...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.1716224115
更新日期:2018-03-13 00:00:00
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journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
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更新日期:2020-11-24 00:00:00
abstract::A cDNA of the human terminal deoxynucleotidyltransferase (TdT; "terminal transferase," EC 2.7.7.31) was isolated from a human lymphoblastoid cell cDNA library in lambda gt 11 by using immunological procedures. Four inserts containing 723 to 939 base pairs were recloned in pBR322 for hybridization and preliminary seque...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
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更新日期:1984-07-01 00:00:00
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journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
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更新日期:1983-03-01 00:00:00
abstract::Evolutionary theory reveals that punishment is effective in promoting cooperation and maintaining social norms. Although it is accepted that emotions are connected to punishment decisions, there remains substantial debate over why humans use costly punishment. Here we show experimentally that constraints on emotion ex...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.0502399102
更新日期:2005-05-17 00:00:00
abstract::Regulated proteolysis is required to execute many cellular programs. In Caulobacter crescentus, timely degradation of the master regulator CtrA by ClpXP protease is essential for cell-cycle progression and requires the colocalization of CtrA and RcdA. Here, we establish a biochemical framework to understand regulated ...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.0701776104
更新日期:2007-04-17 00:00:00
abstract::Abnormal tubulofilamentous structures have been identified in electron micrographs of thin sections and negatively stained impression grids prepared from brains of animals with scrapie and other spongiform encephalopathies, and we showed that such tubules contain a core of filamentous structures resembling scrapie-ass...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.85.10.3575
更新日期:1988-05-01 00:00:00
abstract::X-ray studies on human insulins prepared by semisynthetic and biosynthetic methods have recently been undertaken. Human insulin differs from porcine insulin only at the COOH terminus of the B-chain. The present study reports the crystal structure of 4-zinc human insulin, which is used clinically as a slow-acting prepa...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.81.22.7093
更新日期:1984-11-01 00:00:00
abstract::The genetic evolution of altruism (i.e., a behavior resulting in a net reduction of the survival and/or reproduction of an actor to benefit a recipient) once perplexed biologists because it seemed paradoxical in a Darwinian world. More than half a century ago, W. D. Hamilton explained that when interacting individuals...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章,评审
doi:10.1073/pnas.2013596117
更新日期:2020-11-17 00:00:00
abstract::A rigorous numerical test of a hypothetical mechanism of a molecular motor should model explicitly the diffusive motion of the motor's degrees of freedom as well as the transition rates between the motor's chemical states. We present such a Brownian dynamics, mechanochemcial model of the coarse-grain structure of the ...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.0908192106
更新日期:2009-10-27 00:00:00
abstract::Colocalization of proteins that are part of the same signal transduction pathway via compartmentalization, scaffold, or anchor proteins is an essential aspect of the signal transduction system in eukaryotic cells. If interaction must occur via free diffusion, then the spatial separation between the sources of the two ...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.0401314101
更新日期:2004-04-27 00:00:00
abstract::Structural symmetry is a hallmark of homomeric ion channels. Nonobligatory regulatory proteins can also critically define the precise functional role of such channels. For instance, the pore-forming subunit of the large conductance voltage and calcium-activated potassium (BK, Slo1, or KCa1.1) channels encoded by a sin...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.1804560115
更新日期:2018-10-02 00:00:00
abstract::Striga is a major biotic constraint to sorghum production in semiarid tropical Africa and Asia. Genetic resistance to this parasitic weed is the most economically feasible control measure. Mutant alleles at the LGS1 (LOW GERMINATION STIMULANT 1) locus drastically reduce Striga germination stimulant activity. We provid...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.1618965114
更新日期:2017-04-25 00:00:00
abstract::The primary base sequence of the protein coding regions of the four small heat shock genes of Drosophila melanogaster present at cytological locus 67B has been determined. A single open reading frame large enough to encode a small heat shock protein is found for each gene. The molecular weights of the predicted protei...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.79.7.2360
更新日期:1982-04-01 00:00:00