Abstract:
:The factors shaping cometary nuclei are still largely unknown, but could be the result of concurrent effects of evolutionary and primordial processes. The peculiar bilobed shape of comet 67P/Churyumov-Gerasimenko may be the result of the fusion of two objects that were once separate or the result of a localized excavation by outgassing at the interface between the two lobes. Here we report that the comet's major lobe is enveloped by a nearly continuous set of strata, up to 650 metres thick, which are independent of an analogous stratified envelope on the minor lobe. Gravity vectors computed for the two lobes separately are closer to perpendicular to the strata than those calculated for the entire nucleus and adjacent to the neck separating the two lobes. Therefore comet 67P/Churyumov-Gerasimenko is an accreted body of two distinct objects with 'onion-like' stratification, which formed before they merged. We conclude that gentle, low-velocity collisions occurred between two fully formed kilometre-sized cometesimals in the early stages of the Solar System. The notable structural similarities between the two lobes of comet 67P/Churyumov-Gerasimenko indicate that the early-forming cometesimals experienced similar primordial stratified accretion, even though they formed independently.
journal_name
Naturejournal_title
Natureauthors
Massironi M,Simioni E,Marzari F,Cremonese G,Giacomini L,Pajola M,Jorda L,Naletto G,Lowry S,El-Maarry MR,Preusker F,Scholten F,Sierks H,Barbieri C,Lamy P,Rodrigo R,Koschny D,Rickman H,Keller HU,A'Hearn MF,Agarwal Jdoi
10.1038/nature15511subject
Has Abstractpub_date
2015-10-15 00:00:00pages
402-5issue
7573eissn
0028-0836issn
1476-4687pii
nature15511journal_volume
526pub_type
杂志文章相关文献
NATURE文献大全abstract::Transmissible spongiform encephalopathies are associated with accumulation of PrP(Sc), a conformer of a cellular protein called PrP(C). PrP(Sc) is thought to replicate by imparting its conformation onto PrP(C) (ref. 1), yet conformational discrimination between PrP(C) and PrP(Sc) has remained elusive. Because depositi...
journal_title:Nature
pub_type: 杂志文章
doi:10.1038/35044100
更新日期:2000-11-23 00:00:00
abstract::With the world's focus on reducing our dependency on fossil-fuel energy, the scientific community can investigate new plastic materials that are much less dependent on petroleum than are conventional plastics. Given increasing environmental issues, the idea of replacing plastics with water-based gels, so-called hydrog...
journal_title:Nature
pub_type: 杂志文章
doi:10.1038/nature08693
更新日期:2010-01-21 00:00:00
abstract::Stevens-Johnson syndrome and the related disease toxic epidermal necrolysis are life-threatening reactions of the skin to particular types of medication. Here we show that there is a strong association in Han Chinese between a genetic marker, the human leukocyte antigen HLA-B*1502, and Stevens-Johnson syndrome induced...
journal_title:Nature
pub_type: 杂志文章
doi:10.1038/428486a
更新日期:2004-04-01 00:00:00
abstract::Injury causes a systemic inflammatory response syndrome (SIRS) that is clinically much like sepsis. Microbial pathogen-associated molecular patterns (PAMPs) activate innate immunocytes through pattern recognition receptors. Similarly, cellular injury can release endogenous 'damage'-associated molecular patterns (DAMPs...
journal_title:Nature
pub_type: 杂志文章
doi:10.1038/nature08780
更新日期:2010-03-04 00:00:00
abstract::The bony skeleton is maintained by local factors that regulate bone-forming osteoblasts and bone-resorbing osteoclasts, in addition to hormonal activity. Osteoprotegerin protects bone by inhibiting osteoclastic bone resorption, but no factor has yet been identified as a local determinant of bone mass that regulates bo...
journal_title:Nature
pub_type: 杂志文章
doi:10.1038/nature11000
更新日期:2012-05-03 00:00:00
abstract::For more than four decades, transistors have been shrinking exponentially in size, and therefore the number of transistors in a single microelectronic chip has been increasing exponentially. Such an increase in packing density was made possible by continually shrinking the metal-oxide-semiconductor field-effect transi...
journal_title:Nature
pub_type: 杂志文章
doi:10.1038/nature10676
更新日期:2011-11-16 00:00:00
abstract::Photosynthetic dinoflagellates are important aquatic primary producers and notorious causes of toxic 'red tides'. Typical dinoflagellate chloroplasts differ from all other plastids in having a combination of three envelope membranes and peridinin-chlorophyll a/c light-harvesting pigments. Despite evidence of a dinofla...
journal_title:Nature
pub_type: 杂志文章
doi:10.1038/22099
更新日期:1999-07-08 00:00:00
abstract::Phelan-McDermid syndrome (PMDS) is a complex neurodevelopmental disorder characterized by global developmental delay, severely impaired speech, intellectual disability, and an increased risk of autism spectrum disorders (ASDs). PMDS is caused by heterozygous deletions of chromosome 22q13.3. Among the genes in the dele...
journal_title:Nature
pub_type: 杂志文章
doi:10.1038/nature12618
更新日期:2013-11-14 00:00:00
abstract::Despite considerable global investment, only 60% of people who live with HIV currently receive antiretroviral therapy. The sustainability of current programmes remains unknown and key incidence rates are declining only modestly. Given the complexities and expenses associated with lifelong medication, developing an eff...
journal_title:Nature
pub_type: 杂志文章,评审
doi:10.1038/s41586-019-1841-8
更新日期:2019-12-01 00:00:00
abstract::Interleukin-2 (IL-2) has a key role in the antigen-specific clonal growth of T lymphocytes, by virtue of its interaction with a specific cell-surface receptor (IL-2R). The growth signal seems to be delivered by IL-2 bound to the high-affinity, but not the low-affinity, receptor. Genes encoding IL-2 and its receptor (t...
journal_title:Nature
pub_type: 杂志文章
doi:10.1038/318467a0
更新日期:1985-12-05 00:00:00
abstract::Common genetic contributions to autism spectrum disorder (ASD) reside in risk gene variants that individually have minimal effect sizes. As environmental factors that perturb neurodevelopment also underlie idiopathic ASD, it is crucial to identify altered regulators that can orchestrate multiple ASD risk genes during ...
journal_title:Nature
pub_type: 杂志文章
doi:10.1038/s41586-018-0423-5
更新日期:2018-08-01 00:00:00
abstract::Gene targeting in mouse embryo-derived stem cells has been used to disrupt the homeobox gene hox-1.5. Mice heterozygous at the hox-1.5 locus appear normal, whereas hox-1.5-/hox-1.5- mice die at or shortly after birth. These homozygotes are athymic, aparathyroid, have reduced thyroid and submaxillary tissue and exhibit...
journal_title:Nature
pub_type: 杂志文章
doi:10.1038/350473a0
更新日期:1991-04-11 00:00:00
abstract::Many homeobox genes are clustered in a linear array along a chromosome, reflecting their ordered expression along the anterior-posterior axis of the embryo. Expression patterns as well as grafting, ectopic expression and loss-of-function experiments suggest that the Hox genes encode a combinatorial system of positiona...
journal_title:Nature
pub_type: 杂志文章
doi:10.1038/368747a0
更新日期:1994-04-21 00:00:00
abstract::The violation of a Bell inequality is an experimental observation that forces the abandonment of a local realistic viewpoint--namely, one in which physical properties are (probabilistically) defined before and independently of measurement, and in which no physical influence can propagate faster than the speed of light...
journal_title:Nature
pub_type: 杂志文章
doi:10.1038/nature12012
更新日期:2013-05-09 00:00:00
abstract:: ...
journal_title:Nature
pub_type: 杂志文章
doi:10.1038/d41586-018-07642-0
更新日期:2018-12-01 00:00:00
abstract::Cancer somatic mutations can generate neoantigens that distinguish malignant from normal cells. However, the personalized identification and validation of neoantigens remains a major challenge. Here we discover neoantigens in human mantle-cell lymphomas by using an integrated genomic and proteomic strategy that interr...
journal_title:Nature
pub_type: 杂志文章
doi:10.1038/nature21433
更新日期:2017-03-30 00:00:00
abstract::Using visual information to guide behaviour requires storage in a temporary buffer, known as visual short-term memory (VSTM), that sustains attended information across saccades and other visual interruptions. There is growing debate on whether VSTM capacity is limited to a fixed number of objects or whether it is vari...
journal_title:Nature
pub_type: 杂志文章
doi:10.1038/nature04262
更新日期:2006-03-02 00:00:00
abstract::Single-stranded DNA can fold into well-defined sequence-dependent tertiary structures that specifically bind a variety of target molecules, raising the possibility that some folded single-stranded DNAs might exhibit catalytic activities similar to those of ribozymes and protein enzymes. Derivatives of the hammerhead r...
journal_title:Nature
pub_type: 杂志文章
doi:10.1038/375611a0
更新日期:1995-06-15 00:00:00
abstract::Nuclear pore complexes (NPCs) fuse the inner and outer membranes of the nuclear envelope. They comprise hundreds of nucleoporins (Nups) that assemble into multiple subcomplexes and form large central channels for nucleocytoplasmic exchange1,2. How this architecture facilitates messenger RNA export, NPC biogenesis and ...
journal_title:Nature
pub_type: 杂志文章
doi:10.1038/s41586-020-2670-5
更新日期:2020-10-01 00:00:00
abstract::The emission of isoprene from the leaves of forest trees is a fundamental component of biosphere-atmosphere interactions, controlling many aspects of photochemistry in the lower atmosphere. As almost all commercial agriforest species emit high levels of isoprene, proliferation of agriforest plantations has significant...
journal_title:Nature
pub_type: 杂志文章
doi:10.1038/nature01312
更新日期:2003-01-16 00:00:00
abstract::The orexin (also known as hypocretin) G protein-coupled receptors (GPCRs) respond to orexin neuropeptides in the central nervous system to regulate sleep and other behavioural functions in humans. Defects in orexin signalling are responsible for the human diseases of narcolepsy and cataplexy; inhibition of orexin rece...
journal_title:Nature
pub_type: 杂志文章
doi:10.1038/nature14035
更新日期:2015-03-12 00:00:00
abstract::The assimilation and mineralization of dissolved organic carbon (DOC) by marine bacterioplankton is a major process in the ocean carbon cycle. However, little information exists on the specific metabolic functions of participating bacteria and on whether individual taxa specialize on particular components of the marin...
journal_title:Nature
pub_type: 杂志文章
doi:10.1038/nature06513
更新日期:2008-02-07 00:00:00
abstract::Genetic manipulations of insect populations for pest control have been advocated for some time, but there are few cases where manipulated individuals have been released in the field and no cases where they have successfully invaded target populations. Population transformation using the intracellular bacterium Wolbach...
journal_title:Nature
pub_type: 杂志文章
doi:10.1038/nature10356
更新日期:2011-08-24 00:00:00
abstract::The largest products of magmatic activity on Earth, the great bodies of granite and their corresponding large eruptions, have a dual nature: homogeneity at the large scale and spatial and temporal heterogeneity at the small scale. This duality calls for a mechanism that selectively removes the large-scale heterogeneit...
journal_title:Nature
pub_type: 杂志文章
doi:10.1038/nature09799
更新日期:2011-03-10 00:00:00
abstract::The human gene for the hepatic enzyme phenylalanine hydroxylase has been cloned and used to analyse the phenylalanine hydroxylase locus in the human genome. The detection of polymorphisms in this locus by several restriction enzymes has allowed feasibility studies of prenatal diagnosis of classical phenylketonuria and...
journal_title:Nature
pub_type: 杂志文章
doi:10.1038/306151a0
更新日期:1983-11-10 00:00:00
abstract::The T-cell receptor (TCR) repertoire is selected in the thymus after rearrangement of genes encoding TCR alpha and beta chains. Selection is based on the recognition by newly emergent T cells of self-ligands associated with molecules of the major histocompatibility complex: some combinations result in positive selecti...
journal_title:Nature
pub_type: 杂志文章
doi:10.1038/349531a0
更新日期:1991-02-07 00:00:00
abstract::Electrical current can be completely spin polarized in a class of materials known as half-metals, as a result of the coexistence of metallic nature for electrons with one spin orientation and insulating nature for electrons with the other. Such asymmetric electronic states for the different spins have been predicted f...
journal_title:Nature
pub_type: 杂志文章
doi:10.1038/nature05180
更新日期:2006-11-16 00:00:00
abstract::Functioning and processing of membrane proteins critically depend on the way their transmembrane segments are embedded in the membrane. Sphingolipids are structural components of membranes and can also act as intracellular second messengers. Not much is known of sphingolipids binding to transmembrane domains (TMDs) of...
journal_title:Nature
pub_type: 杂志文章
doi:10.1038/nature10742
更新日期:2012-01-09 00:00:00
abstract::Thermoelectric materials are of interest for applications as heat pumps and power generators. The performance of thermoelectric devices is quantified by a figure of merit, ZT, where Z is a measure of a material's thermoelectric properties and T is the absolute temperature. A material with a figure of merit of around u...
journal_title:Nature
pub_type: 杂志文章
doi:10.1038/35098012
更新日期:2001-10-11 00:00:00
abstract::Aberrant neovascularization contributes to diseases such as cancer, blindness and atherosclerosis, and is the consequence of inappropriate angiogenic signalling. Although many regulators of pathogenic angiogenesis have been identified, our understanding of this process is incomplete. Here we explore the transcriptome ...
journal_title:Nature
pub_type: 杂志文章
doi:10.1038/nature12345
更新日期:2013-07-18 00:00:00