Abstract:
:In the usual Darwinian case in which struggle for existence leads to density limitations on the environment's carrying capacity, R. A. Fisher's reproductive-value concept reduces to zero for every initial age group. To salvage some meaning for Fisher's notion, two variant reproductive-value concepts are defined here: an "incipient reproductive-value function," applicable to a system's early dilute stage when density effects are still ignorable; and a "second-order penultimate reproductive-value function," linking to a system's initial conditions near equilibrium its much later small deviations from carrying-capacity equilibrium. Also, slowly changing age-structured mortality and fertility parameters of Lotka and Mendelian mating systems are shown to suggest linear reproductive-value surrogates that provide approximations for truly nonlinear diploid and haploid models.
journal_name
Proc Natl Acad Sci U S Aauthors
Samuelson PAdoi
10.1073/pnas.75.12.6327subject
Has Abstractpub_date
1978-12-01 00:00:00pages
6327-31issue
12eissn
0027-8424issn
1091-6490journal_volume
75pub_type
杂志文章abstract::Combined intracellular and microfluorometric recording techniques were used to evaluate whether the inhibition by cholinergic or adrenergic transmitters of the Ca2(+)-activated potassium current (IAHP) in hippocampal CA3 pyramidal cells was mediated by an alteration of depolarization-induced change in cytosolic free C...
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.87.11.4083
更新日期:1990-06-01 00:00:00
abstract::We studied the effect of gangliosides GD1a and GM1 on the lamellar-to-hexagonal II phase transition of mixtures of dioleoylphosphatidylethanolamine/dioleoylphosphatidyl choline, 3:1, and of transphosphatidylated phosphatidylethanolamine with dioleoylglycerol by high-sensitivity differential scanning calorimetry, 31P-N...
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.91.21.10019
更新日期:1994-10-11 00:00:00
abstract::Nonhuman primates possess a highly developed capacity for face recognition, which resembles the human capacity both cognitively and neurologically. Face recognition is typically tested by having subjects compare facial images, whereas there has been virtually no attention to how they connect these images to reality. C...
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.0912174106
更新日期:2009-12-22 00:00:00
abstract::The rat anterior pituitary gland (AP) receives all of its blood supply via the hypophyseal portal circulation. We now report, in rats with estradiol (E2)-induced prolactin-secreting tumors, that newly formed arteries directly supply the AP and that this arteriogenesis is closely correlated with the sensitivity of 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.81.14.4549
更新日期:1984-07-01 00:00:00
abstract::Underacetylation of histone H4 is thought to be involved in the molecular mechanism of mammalian X chromosome inactivation, which is an important model system for large-scale genetic control in eukaryotes. However, it has not been established whether histone underacetylation plays a critical role in the multistep inac...
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.94.18.9665
更新日期:1997-09-02 00:00:00
abstract::Selective autophagy of damaged mitochondria requires autophagy receptors optineurin (OPTN), NDP52 (CALCOCO2), TAX1BP1, and p62 (SQSTM1) linking ubiquitinated cargo to autophagic membranes. By using quantitative proteomics, we show that Tank-binding kinase 1 (TBK1) phosphorylates all four receptors on several autophagy...
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.1523926113
更新日期:2016-04-12 00:00:00
abstract::P450c17 is the single enzyme mediating both 17 alpha-hydroxylase (steroid 17 alpha-monooxygenase, EC 1.14.99.9) and 17,20 lyase activities in the synthesis of steroid hormones. It has been suggested that different P450c17 isozymes mediate these activities in the adrenal gland and testis. We sequenced 423 of the 509 am...
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.84.2.407
更新日期:1987-01-01 00:00:00
abstract::Secondary (i.e., heterotrophic or animal) production is a main pathway of energy flow through an ecosystem as it makes energy available to consumers, including humans. Its estimation can play a valuable role in the examination of linkages between ecosystem functions and services. We found that oil and gas platforms of...
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.1411477111
更新日期:2014-10-28 00:00:00
abstract::Although much is known about the underlying mechanisms of p53 activity and regulation, the factors that influence the diversity and duration of p53 responses are not well understood. Here we describe a unique mode of p53 regulation involving alternative splicing of the TP53 gene. We found that the use of an alternativ...
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.1321640111
更新日期:2014-08-12 00:00:00
abstract::Treatment of cultured human tumor cells with the chloroethylnitrosourea antitumor drug 1,3-bis(2-chloroethyl)-1-nitrosourea (BCNU) selectively induces transcription and protein synthesis of a subset of the human heat shock or stress-induced genes (HSP90 and HSP70) with little effect on other stress genes or on express...
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.88.11.4825
更新日期:1991-06-01 00:00:00
abstract::The lineage-determining transcription factor CCAAT enhancer binding protein alpha (C/EBPalpha) is required for myeloid differentiation. Decreased function or expression of C/EBPalpha is often found in human acute myeloid leukemia. However, the precise impact of C/EBPalpha deficiency on the maturation arrest in leukemo...
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.0508143103
更新日期:2006-04-18 00:00:00
abstract::The distribution of dopamine-containing processes in the striatum of fetal and neonatal cats was studied by immunohistochemical and glyoxylic acid histofluorescence methods and compared to the distribution of acetylcholinesterase (acetylcholine acetylhydrolase, EC 3.1.1.7) observed by thiocholine histochemistry in 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.78.9.5871
更新日期:1981-09-01 00:00:00
abstract::Cerebral arteriovenous malformations (AVMs) are common vascular malformations, which may result in hemorrhagic strokes and neurological deficits. Bone morphogenetic protein (BMP) and Notch signaling are both involved in the development of cerebral AVMs, but the cross-talk between the two signaling pathways is poorly u...
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.1310905110
更新日期:2013-11-19 00:00:00
abstract::Information concerning the dynamics of river meandering is embedded in their planforms. Here, we focus on how bend skewing varies with increasing sinuosity, and how flow direction is embedded in bend skewing. It has often been thought that upstream-skewed bends are dominant within a sufficiently long reach. These bend...
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.1910874116
更新日期:2019-11-19 00:00:00
abstract::An endonucleolytic activity is associated with purified PM(2) bacteriophages. It converts the double-stranded supercoiled PM(2) DNA mostly into the linear form that sediments as a homogenous peak in alkaline sucrose gradients. The same activity is found in intact or detergent-lysed phages. Optimal activity is observed...
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.71.12.4965
更新日期:1974-12-01 00:00:00
abstract::Transforming growth factor beta (TGF-beta)-mediated G(1) arrest previously has been shown to specifically target inactivation of cyclin D:cyclin-dependent kinase (Cdk) 4/6 complexes. We report here that TGF-beta-treated human HepG2 hepatocellular carcinoma cells arrest in G(1), but retain continued cyclin D:Cdk4/6 act...
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.96.26.14961
更新日期:1999-12-21 00:00:00
abstract::The INT6 gene has been implicated in human breast cancer formation, but its function is unknown. We isolated an Int6 homolog from fission yeast, Yin6, by its binding to a conserved protein in the Ras pathway, Moe1. Yin6 and Moe1 converge on the same protein complex to promote microtubule instability/disassembly. Yin6 ...
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.97.26.14370
更新日期:2000-12-19 00:00:00
abstract::ATP-sensitive potassium (KATP) channels in the pancreatic beta cell membrane mediate insulin release in response to elevation of plasma glucose levels. They are open at rest but close in response to glucose metabolism, producing a depolarization that stimulates Ca2+ influx and exocytosis. Metabolic regulation of KATP ...
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.95.12.7185
更新日期:1998-06-09 00:00:00
abstract::Hybrid dysgenesis in Drosophila is a syndrome of gonadal atrophy, sterility, and male recombination, and it occurs in the progeny of crosses between males that harbor certain transposable elements (TEs) and females that lack them. Known examples of hybrid dysgenesis in Drosophila melanogaster result from mobilization ...
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.0508192102
更新日期:2005-11-01 00:00:00
abstract::The mouse genes encoding the constitutively expressed complement component C4 and its closely related isoform C4-Slp (sex-limited protein), which is expressed only in male animals of several strains, provide a unique model to study sequence elements and trans-acting factors responsible for androgen responsiveness. Our...
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.95.15.8750
更新日期:1998-07-21 00:00:00
abstract::Pollen tubes are highly polarized plant cells specialized in delivering sperm for fertilization. Pollen tube growth is rapid, occurs exclusively at the tip, and can reach distances thousands of times the diameter of the pollen grain without cell division, thus representing an excellent model system for studying asymme...
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.1008527107
更新日期:2010-09-14 00:00:00
abstract::Picosecond studies of rhodopsin in low-temperature glasses have been carried out in order to observe directly the risetime of prelumirhodopsin, the first intermediate in the visual pathway. Only at 20 K or below can the risetime of this intermediate be resolved and even at 4 K it is astoundingly rapid, about 36 psec. ...
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.74.8.3119
更新日期:1977-08-01 00:00:00
abstract::Copper homeostasis is essential for bacterial pathogen fitness and infection, and has been the focus of a number of recent studies. In Salmonella, envelope protection against copper overload and macrophage survival depends on CueP, a major copper-binding protein in the periplasm. This protein is also required to deliv...
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.1603192113
更新日期:2016-10-11 00:00:00
abstract::Shell shape and shell thickness of the intertidal snail Littorina obtusata changed markedly between 1871 and 1984 in northern New England. Shells collected prior to 1900 were high-spired with thin walls, whereas shells collected in 1982-84 were low-spired with thick walls. An intertidal crab (Carcinus maenas) which 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.83.18.6897
更新日期:1986-09-01 00:00:00
abstract::CCAAT displacement protein (CDP), a nuclear protein of 180-190 kDa, contains a triplicated motif, the cut domain, similar (80-90% conserved) to three repeats of 60-65 amino acids first identified in Drosophila cut, a homeo-domain protein involved in cell-fate decisions in development. Cut repeats bind DNA and exhibit ...
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.91.16.7757
更新日期:1994-08-02 00:00:00
abstract::The bacterial TATAAT -10 region sequence was the first promoter element to be identified, but how it functions is still not clear. Because the duplex element is melted during initiation, the effects of substitutions were studied in both single-and double-strand contexts. Band-shift results were particularly unexpected...
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.161085798
更新日期:2001-07-31 00:00:00
abstract::Sympathetic activation of β-adrenoreceptors (β-AR) represents a hallmark in the development of heart failure (HF). However, little is known about the underlying mechanisms of gene regulation. In human ventricular myocardium from patients with end-stage HF, we found high levels of phosphorylated histone 3 at serine-28 ...
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.1816521116
更新日期:2019-10-29 00:00:00
abstract::We obtain a collection of multilinear Littlewood-Paley estimates, which we then apply to two problems in partial differential equations. The first problem is the estimation of the square root of an elliptic operator in divergence form, and the second is the estimation of solutions to the Cauchy problem for nondivergen...
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.79.18.5746
更新日期:1982-09-01 00:00:00
abstract::The reactions catalyzed by Mo enzymes each find the product differing from the substrate by two electrons and two protons (or some multiple thereof). The coordination chemistry of Mo suggests that there is a distinct relationship between acid-base and redox properties of Mo complexes, and that a coupled electron-proto...
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.70.4.988
更新日期:1973-04-01 00:00:00
abstract::The NOVH protein belongs to the emerging CCN [Connective tissue growth factor (CTGF), Cyr61/Cef10, nephroblastoma overexpressed gene] family of growth regulators sharing a strikingly conserved multimodular organization but exhibiting distinctive functional features. Two members of the family (CYR61 and CTGF) are posit...
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.96.3.869
更新日期:1999-02-02 00:00:00