Abstract:
:The question of what is a perceptual object is one of the most central and also controversial issues in cognitive science. According to the topological approach to perceptual organization, the core intuitive notion of an object--the holistic identity preserved over shape-changing transformations--may be characterized precisely as topological invariance. Here we show that, across a series of multiple-object tracking tasks, performance was not disrupted when the moving items underwent massive featural changes. However, performance was significantly impaired when the items changed their topological properties of holes, demonstrating that topological invariance constrains what counts as an object in the first place. Consistent with previous findings, fMRI studies indicated that the anterior temporal lobe may be involved in the formation of object representation defined by topological constraints.
journal_name
Proc Natl Acad Sci U S Aauthors
Zhou K,Luo H,Zhou T,Zhuo Y,Chen Ldoi
10.1073/pnas.1010919108subject
Has Abstractpub_date
2010-12-14 00:00:00pages
21920-4issue
50eissn
0027-8424issn
1091-6490pii
1010919108journal_volume
107pub_type
杂志文章abstract::A single, modified nucleoside in Escherichia coli tRNA, 6-(3-methyl-2-butenylamino)-2-methyl-thio-9-beta-D-ribofuranosylpurine, has been desulfurized with Raney nickel to afford its probable biosynthetic precursor. The limitations of the reaction at the nucleoside and tRNA levels and its lack of inhibition of the amin...
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.68.1.48
更新日期:1971-01-01 00:00:00
abstract::Physiological properties of the flagellar rotary motor have been taken to indicate a tightly coupled mechanism in which each revolution is driven by a fixed number of energizing ions. Measurements that would directly test the tight-coupling hypothesis have not been made. Energizing ions flow through membrane-bound com...
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.1419955112
更新日期:2015-04-14 00:00:00
abstract::The archaeological record shows that typically human cultural traits emerged at different times, in different parts of the world, and among different hominin taxa. This pattern suggests that their emergence is the outcome of complex and nonlinear evolutionary trajectories, influenced by environmental, demographic, and...
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.1620752114
更新日期:2017-07-25 00:00:00
abstract::We report here the biologically active conformation of acetylcholine when bound to the high-affinity state of the receptor from Torpedo californica. The acetylcholine conformation was determined in the free and bound states by proton NMR two-dimensional nuclear Overhauser effects. In agreement with x-ray crystallograp...
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.85.18.6721
更新日期:1988-09-01 00:00:00
abstract::To study C(0)a priori estimates for solutions to certain complex Monge-Ampère equations, I introduce a coherent sheaf of ideals and show that it satisfies various global algebrogeometric conditions, including a cohomology vanishing theorem. This technique is used to establish the existence of Kähler-Einstein metrics o...
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.86.19.7299
更新日期:1989-10-01 00:00:00
abstract::The consumption of garlic is inversely correlated with the progression of cardiovascular disease, although the responsible mechanisms remain unclear. Here we show that human RBCs convert garlic-derived organic polysulfides into hydrogen sulfide (H(2)S), an endogenous cardioprotective vascular cell signaling molecule. ...
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.0705710104
更新日期:2007-11-13 00:00:00
abstract::Cell cycle checkpoints are evolutionarily conserved surveillance systems that protect genomic stability and prevent oncogenesis in mammals. One important target of checkpoint control is ribonucleotide reductase (RNR), which catalyzes the rate-limiting step in dNTP and DNA synthesis. In both yeast and humans, RNR is tr...
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.062502299
更新日期:2002-03-19 00:00:00
abstract::The x-ray sensitive hamster cell line xrs-6 is deficient in DNA double-strand break (DSB) repair and exhibits impaired V(D)J recombination. The molecular defect in this line is in the 80-kDa subunit of the Ku autoantigen, a protein that binds to DNA ends and recruits the DNA-dependent protein kinase to DNA. Using an I...
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.93.17.8929
更新日期:1996-08-20 00:00:00
abstract::The perforant path (PP) undergoes synaptic changes in the course of aging and dementia. Previous studies attempting to assess the integrity of the PP in humans using diffusion tensor imaging (DTI) were limited by low resolution and the inability to identify PP fibers specifically. Here we present an application of DTI...
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.1002113107
更新日期:2010-07-13 00:00:00
abstract::Memory CD8 T cells provide durable protection against diverse intracellular pathogens and can be broadly segregated into distinct circulating and tissue-resident populations. Paradigmatic studies have demonstrated that circulating memory cells can be further divided into effector memory (Tem) and central memory (Tcm) ...
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.2008571117
更新日期:2020-10-13 00:00:00
abstract::Human Creutzfeldt-Jakob disease (CJD) and similar neurodegenerative diseases such as sheep scrapie are caused by a variety of related infectious agents. They are associated with abnormal host prion protein (PrP), which is assessed by limited proteolysis to yield resistant PrP bands (PrP-res). Although PrP-res has been...
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.0400158101
更新日期:2004-06-08 00:00:00
abstract::We report two instances of selective accumulation of herpes simplex 1 RNA transcripts in different compartments of infected HEp-2 cells. In the first, transcripts derived from about 50% of the viral DNA accumulated in the nuclei of cells 8 hr after infection. However, only 40-42% of the DNA was represented in transcri...
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.71.11.4322
更新日期:1974-11-01 00:00:00
abstract::Previous studies have shown that DNA methyltransferase (Dnmt) 1 is required for maintenance of bulk DNA methylation and is essential for mouse development. However, somatic disruption of DNMT1 in the human cancer cell line HCT116 was not lethal and caused only minor decreases in methylation. Here, we report the identi...
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.0604602103
更新日期:2006-09-19 00:00:00
abstract::An antiserum was prepared in rabbits against an antigen obtained by density gradient sedimentation of centrifuged medium from monolayer cultures of spleens involved by Hodgkin's disease. The antiserum was tested by isotopic antibody techniques with cells from each of eight cultures derived from spleens involved by Hod...
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.71.7.2605
更新日期:1974-07-01 00:00:00
abstract::In the retina, dopamine plays a central role in neural adaptation to light. Progress in the study of dopaminergic amacrine (DA) cells has been limited because they are very few (450 in each mouse retina, 0.005% of retinal neurons). Here, we applied transgenic technology, single-cell global mRNA amplification, and cDNA...
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.0400913101
更新日期:2004-04-06 00:00:00
abstract::T cell recognition typically involves both the engagement of a specific T cell receptor with a peptide/major histocompatibility complex (MHC) and a number of accessory interactions. One of the most important interactions is between the integrin lymphocyte function-associated antigen 1 (LFA-1) on the T cell and intrace...
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.95.11.6302
更新日期:1998-05-26 00:00:00
abstract::The steady-state level and synthesis of a pair of polypeptides of Mr 33,000 and 35,000 in chicken embryo fibroblasts (CEF) transformed by Rous sarcoma virus (RSV) are significantly decreased relative to normal CEF; however, the decrease is more pronounced in the case of the Mr 35,000 polypeptide. These polypeptides ha...
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.78.9.5633
更新日期:1981-09-01 00:00:00
abstract::Visual speech facilitates auditory speech perception, but the visual cues responsible for these benefits and the information they provide remain unclear. Low-level models emphasize basic temporal cues provided by mouth movements, but these impoverished signals may not fully account for the richness of auditory informa...
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.2002887117
更新日期:2020-07-21 00:00:00
abstract::Recently several attempts to identify oxygen-derived radicals in whole cells by spin trapping and electron spin resonance have been reported by using 5,5-dimethyl-1-pyrroline-N-oxide as the spin trap. In the present study, the feasibility of this method is examined. Chinese hamster V79 cells and human erythrocytes ser...
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.83.20.7593
更新日期:1986-10-01 00:00:00
abstract::Conversion of carbon dioxide into hydrocarbons using solar energy is an attractive strategy for storing such a renewable source of energy into the form of chemical energy (a fuel). This can be achieved in a system coupling a photovoltaic (PV) cell to an electrochemical cell (EC) for CO2 reduction. To be beneficial and...
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.1815412116
更新日期:2019-05-14 00:00:00
abstract::Several disulfide benzamides have been shown to possess wide-spectrum antiretroviral activity in cell culture at low micromolar to submicromolar concentrations, inhibiting human immunodeficiency virus (HIV) type 1 (HIV-1) clinical and drug-resistant strains along with HIV-2 and simian immunodeficiency virus [Rice, W. ...
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.93.3.969
更新日期:1996-02-06 00:00:00
abstract::We have studied androgen binding characteristics of cells for androgen insensitivity from an obligate heterozygote, who is the mother of three male pseudohermaphrodites with dihydrotestosterone (17beta-hydroxy-5alpha-androstan-3-one) receptor deficiency. Specific dihydrotestosterone binding by skin fibroblasts from he...
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.72.4.1469
更新日期:1975-04-01 00:00:00
abstract::The Raf family includes three members, of which B-Raf is frequently mutated in melanoma and other tumors. We show that Raf-1 and A-Raf require Hsp90 for stability, whereas B-Raf does not. In contrast, mutated, activated B-Raf binds to an Hsp90-cdc37 complex, which is required for its stability and function. Exposure o...
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.0609973103
更新日期:2006-01-03 00:00:00
abstract::We have cloned and determined the entire nucleotide sequence of cDNAs corresponding to the putative alpha subunits of the human and rat mast cell high-affinity IgE receptors. Both human and rat cDNAs encode an NH2-terminal signal peptide, two immunoglobulin-like extracellular domains (encoded by discrete exons), a hyd...
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.85.6.1907
更新日期:1988-03-01 00:00:00
abstract::A neuroethological approach to human and nonhuman primate behavior and cognition predicts biological specializations for social life. Evidence reviewed here indicates that ancestral mechanisms are often duplicated, repurposed, and differentially regulated to support social behavior. Focusing on recent research from no...
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.1301213110
更新日期:2013-06-18 00:00:00
abstract::A polar lipid containing about 20 per cent of the lipid soluble inositol has been purified from cells of Saccharomyces cerevisiae. This compound labeled with (3)H-inositol, (32)P(i), or (14)C glucose was isolated from aqueous pyridine extracts by means of paper chromatography. Unlabeled compound was obtained by a diff...
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.64.3.1042
更新日期:1969-11-01 00:00:00
abstract::An investigation by paramagnetic resonance spectroscopy of the photoreduction of ferredoxin, oxygenically by water and anoxygenically by a direct electron donor to photosystem I, led to the unexpected findings that different reductive mechanisms may be involved. Ferredoxin photoreduced by water was not reoxidized in 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.77.5.2676
更新日期:1980-05-01 00:00:00
abstract::A molecular model of poorly understood hydrophobic effects is heuristically developed using the methods of information theory. Because primitive hydrophobic effects can be tied to the probability of observing a molecular-sized cavity in the solvent, the probability distribution of the number of solvent centers in a ca...
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.93.17.8951
更新日期:1996-08-20 00:00:00
abstract::During response of budding yeast to peptide mating pheromone, the cell becomes markedly polarized and MAPK scaffold protein Ste5 localizes to the resulting projection (shmoo tip). We demonstrated before that this recruitment is essential for sustained MAPK signaling and requires interaction of a pleckstrin homology (P...
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.1005817107
更新日期:2010-06-29 00:00:00
abstract::Stem cells have been identified as essential for maintaining multiple organ systems, including the hematopoietic system. The distinct cell fates of self-renewal and differentiation of hematopoietic stem cells (HSCs) depend on cell division. Recently, several negative regulators of the cell cycle, such as the cyclin-de...
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.0603389103
更新日期:2006-06-13 00:00:00