Abstract:
:Rising sea levels and increased storminess are expected to accelerate the erosion of soft-cliff coastlines, threatening coastal infrastructure and livelihoods. To develop predictive models of future coastal change we need fundamentally to know how rapidly coasts have been eroding in the past, and to understand the driving mechanisms of coastal change. Direct observations of cliff retreat rarely extend beyond 150 y, during which humans have significantly modified the coastal system. Cliff retreat rates are unknown in prior centuries and millennia. In this study, we derived retreat rates of chalk cliffs on the south coast of Great Britain over millennial time scales by coupling high-precision cosmogenic radionuclide geochronology and rigorous numerical modeling. Measured 10Be concentrations on rocky coastal platforms were compared with simulations of coastal evolution using a Monte Carlo approach to determine the most likely history of cliff retreat. The 10Be concentrations are consistent with retreat rates of chalk cliffs that were relatively slow (2-6 cm⋅y-1) until a few hundred years ago. Historical observations reveal that retreat rates have subsequently accelerated by an order of magnitude (22-32 cm⋅y-1). We suggest that acceleration is the result of thinning of cliff-front beaches, exacerbated by regional storminess and anthropogenic modification of the coast.
journal_name
Proc Natl Acad Sci U S Aauthors
Hurst MD,Rood DH,Ellis MA,Anderson RS,Dornbusch Udoi
10.1073/pnas.1613044113subject
Has Abstractpub_date
2016-11-22 00:00:00pages
13336-13341issue
47eissn
0027-8424issn
1091-6490pii
1613044113journal_volume
113pub_type
杂志文章abstract::Through a process called "bioturbation," burrowing macrofauna have altered the seafloor habitat and modified global carbon cycling since the Cambrian. However, the impact of macrofauna on the community structure of microorganisms is poorly understood. Here, we show that microbial communities across bioturbated, but ge...
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.1917494117
更新日期:2020-07-07 00:00:00
abstract::Antigen receptor-stimulated cell death of developing, immature T cells plays an important role in shaping the repertoire of antigens to which mature T cells will respond, but a role for receptor-stimulated death in controlling responses of mature T cells is controversial. Mutant lpr/lpr mice exhibit an autoimmune synd...
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.90.10.4409
更新日期:1993-05-15 00:00:00
abstract::Apolipoprotein E (apoE) secreted by macrophages in the artery wall exerts an important protective effect against the development of atherosclerosis, presumably through its ability to promote lipid efflux. Previous studies have shown that increases in cellular free cholesterol levels stimulate apoE transcription in mac...
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.021488798
更新日期:2001-01-16 00:00:00
abstract::Human diploid fibroblasts (HDFs) possess Ca(2+)-dependent membrane currents. These currents were suppressed in late-passage normal (senescent) HDFs and prematurely senescent HDFs derived from a subject with Werner syndrome (WS), compared with early-passage normal (young) HDFs. When young HDFs were microinjected with m...
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.91.6.2186
更新日期:1994-03-15 00:00:00
abstract::Interaction of syntaxin 1 with the alpha(1D) subunit of the voltage-gated L type Ca(2+) channel was investigated in the pancreatic beta cell. Coexpression of the enhanced green fluorescent protein-linked alpha(1D) subunit with the enhanced blue fluorescent protein-linked syntaxin 1 and Western blot analysis together 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.96.18.10164
更新日期:1999-08-31 00:00:00
abstract::We show that the motion of a slightly compressible fluid is near that of an incompressible fluid. That is, for a given initial velocity field, the motion of a compressible fluid with large sound speed is near to that of an idealized incompressible fluid. We consider the compressible fluid motion in Lagrangian coordina...
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.72.2.539
更新日期:1975-02-01 00:00:00
abstract::The extensive intratumor heterogeneity revealed by sequencing cancer genomes is an essential determinant of tumor progression, diagnosis, and treatment. What maintains heterogeneity remains an open question because competition within a tumor leads to a strong selection for the fittest subclone. Cancer cells also coope...
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.1414653112
更新日期:2015-02-10 00:00:00
abstract::L-type Ca(2+) channels play a critical role in regulating Ca(2+)-dependent signaling in cardiac myocytes, including excitation-contraction coupling; however, the subcellular localization of cardiac L-type Ca(2+) channels and their regulation are incompletely understood. Caveolae are specialized microdomains of the pla...
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.0503465103
更新日期:2006-05-09 00:00:00
abstract::Ribbon synapses of photoreceptor cells and second-order bipolar neurons in the retina are specialized to transmit graded signals that encode light intensity. Neurotransmitter release at ribbon synapses exhibits two kinetically distinct components, which serve different sensory functions. The faster component is deplet...
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.1323962111
更新日期:2014-06-10 00:00:00
abstract::Professional antigen-presenting dendritic cells (DCs) are critical in regulating T cell immune responses at both systemic and mucosal sites. Many Lactobacillus species are normal members of the human gut microflora and most are regarded as safe when administered as probiotics. Because DCs can naturally or therapeutica...
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.0500098102
更新日期:2005-02-22 00:00:00
abstract::Loquacious-PD (Loqs-PD) is required for biogenesis of many endogenous siRNAs in Drosophila In vitro, Loqs-PD enhances the rate of dsRNA cleavage by Dicer-2 and also enables processing of substrates normally refractory to cleavage. Using purified components, and Loqs-PD truncations, we provide a mechanistic basis for L...
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.1707063114
更新日期:2017-09-19 00:00:00
abstract::The reduction in levels of the potentially toxic amyloid-beta peptide (Abeta) has emerged as one of the most important therapeutic goals in Alzheimer's disease. Key targets for this goal are factors that affect the expression and processing of the Abeta precursor protein (betaAPP). Earlier reports from our laboratory ...
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.131152998
更新日期:2001-06-19 00:00:00
abstract::Progressive amyloid deposition in senile plaques and cortical blood vessels may play a central role in the pathogenesis of Alzheimer disease. We have used x-ray diffraction and electron microscopy to study the molecular organization and morphology of macromolecular assemblies formed by three synthetic peptides homolog...
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.84.19.6953
更新日期:1987-10-01 00:00:00
abstract::By the combined use of DNase I footprinting, electrophoretic mobility-shift assay, and methylation interference analysis, we have identified a series of sequence-specific protein-DNA interactions in the 5' flanking region of the rat osteocalcin gene. Stimulation of osteocalcin gene expression by 1,25-dihydroxyvitamin ...
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.87.5.1701
更新日期:1990-03-01 00:00:00
abstract::Distribution studies disclosed that all major cerebral arteries and cortical arterioles of the cat were invested with fine varicose nerve fibers that contained calcitonin gene-related peptide (CGRP)-like immunoreactivity; the trigeminal ganglia likewise contained CGRP immunoreactivity. Sequential immunostaining with a...
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.83.15.5731
更新日期:1986-08-01 00:00:00
abstract::Expansion of myeloid cells associated with solid tumor development is a key contributor to neoplastic progression. Despite their clinical relevance, the mechanisms controlling myeloid cell production and activity in cancer remains poorly understood. Using a multistage mouse model of breast cancer, we show that product...
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.1424927112
更新日期:2015-02-10 00:00:00
abstract::Animals are typically colonized by diverse bacterial symbionts, many of which are commensal and, in numerous cases, even essential for their host's proper development and growth. In exchange, the host must supply a sufficient array and quantity of nutrients to support the proliferation and persistence of its microbial...
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.95.4.1818
更新日期:1998-02-17 00:00:00
abstract::Injection of rat kidney cortex mRNA into Xenopus laevis oocytes leads to a stimulation of Na(+)-dependent SO4(2-) uptake. Based on this information, we have isolated from a corresponding library a cDNA (NaSi-1) that is most likely related to a Na+/SO4(2-) cotransport system. NaSi-1 cRNA leads in a time- and dose-depen...
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.90.17.8073
更新日期:1993-09-01 00:00:00
abstract::An unprecedented, spontaneous, and complete cleavage of the triple bond of N2 in the thermal reaction of 15N2 with Ta214N+ was observed experimentally by Fourier transform ion cyclotron resonance mass spectrometry; mechanistic aspects of the degenerate ligand exchange were addressed by high-level quantum chemical calc...
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.1913664116
更新日期:2019-10-22 00:00:00
abstract::Prenatal stress exposure is associated with risk for psychiatric disorders later in life. This may be mediated in part via enhanced exposure to glucocorticoids (GCs), which are known to impact neurogenesis. We aimed to identify molecular mediators of these effects, focusing on long-lasting epigenetic changes. In a hum...
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.1820842116
更新日期:2020-09-22 00:00:00
abstract::Since the days of Hertz, radio transmitters have evolved from rudimentary circuits emitting around 50 MHz to modern ubiquitous Wi-Fi devices operating at gigahertz radio bands. As wireless data traffic continues to increase, there is a need for new communication technologies capable of high-frequency operation for hig...
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.1903534116
更新日期:2019-05-07 00:00:00
abstract::The succession from aerobic and facultative anaerobic bacteria to obligate anaerobes in the infant gut along with the differences between the compositions of the mucosally adherent vs. luminal microbiota suggests that the gut microbes consume oxygen, which diffuses into the lumen from the intestinal tissue, maintainin...
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.1718635115
更新日期:2018-04-17 00:00:00
abstract::Activated RAS transforming genes that encode proteins (p21s) with amino acid substitutions at positions 12, 13, or 61 have been detected in 10-20% of human neoplasms. This report describes a monoclonal antibody (DWP) raised against a synthetic peptide corresponding to amino acids 5-16 of a mutated RAS gene encoding Va...
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.83.19.7485
更新日期:1986-10-01 00:00:00
abstract::Estrogen is known to influence pain, but the specific roles of the two estrogen receptors (ERs) in the spinal cord are unknown. In the present study, we have examined the expression of ERalpha and ERbeta in the spinal cord and have looked for defects in pain pathways in ERbeta knockout (ERbeta(-/-)) mice. In the spina...
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.0705936104
更新日期:2007-08-21 00:00:00
abstract::The complexed (ribosome-bearing) membrane fraction of Bacillus subtilis contains several proteins (CM-proteins) that are virtually absent from the ribosome-free fraction and hence might be components of the apparatus of protein secretion. We have determined, by trypsin digestion and by labeling with a nonpenetrating r...
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.80.11.3287
更新日期:1983-06-01 00:00:00
abstract::The plant hormone indole-acetic acid (auxin) is essential for many aspects of plant development. Auxin-mediated growth regulation typically involves the establishment of an auxin concentration gradient mediated by polarly localized auxin transporters. The localization of auxin carriers and their amount at the plasma m...
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.1309057110
更新日期:2013-10-01 00:00:00
abstract::Previous studies have suggested that most papillomaviruses enter the host cell via clathrin-dependent receptor-mediated endocytosis but have not addressed later steps in viral entry. To examine these events, we followed the localization of L2 and packaged DNA after entry of infectious virions or L1/L2 pseudovirions. 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.0404229101
更新日期:2004-09-28 00:00:00
abstract::Declining biodiversity and ecosystem functions put many of nature's contributions to people at risk. We review and synthesize the scientific literature to assess 50-y global trends across a broad range of nature's contributions. We distinguish among trends in potential and realized contributions of nature, as well as ...
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.2010473117
更新日期:2020-12-22 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::The budding yeast Saccharomyces cerevisiae initiates polarized growth or budding once per cell cycle at a specific time of the cell cycle and at a specific location on the cell surface. Little is known about the molecular nature of the temporal and spatial regulatory mechanisms. It is also unclear what factors, if any...
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.182370299
更新日期:2002-09-17 00:00:00