排序方式: 共有87条查询结果,搜索用时 15 毫秒
41.
Finlayson C Pacheco FG Rodríguez-Vidal J Fa DA Gutierrez López JM Santiago Pérez A Finlayson G Allue E Baena Preysler J Cáceres I Carrión JS Fernández Jalvo Y Gleed-Owen CP Jimenez Espejo FJ López P López Sáez JA Riquelme Cantal JA Sánchez Marco A Guzman FG Brown K Fuentes N Valarino CA Villalpando A Stringer CB Martinez Ruiz F Sakamoto T 《Nature》2006,443(7113):850-853
The late survival of archaic hominin populations and their long contemporaneity with modern humans is now clear for southeast Asia. In Europe the extinction of the Neanderthals, firmly associated with Mousterian technology, has received much attention, and evidence of their survival after 35 kyr bp has recently been put in doubt. Here we present data, based on a high-resolution record of human occupation from Gorham's Cave, Gibraltar, that establish the survival of a population of Neanderthals to 28 kyr bp. These Neanderthals survived in the southernmost point of Europe, within a particular physiographic context, and are the last currently recorded anywhere. Our results show that the Neanderthals survived in isolated refuges well after the arrival of modern humans in Europe. 相似文献
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Eelkema R Pollard MM Vicario J Katsonis N Ramon BS Bastiaansen CW Broer DJ Feringa BL 《Nature》2006,440(7081):163
Nanomachines of the future will require molecular-scale motors that can perform work and collectively induce controlled motion of much larger objects. We have designed a synthetic, light-driven molecular motor that is embedded in a liquid-crystal film and can rotate objects placed on the film that exceed the size of the motor molecule by a factor of 10,000. The changes in shape of the motor during the rotary steps cause a remarkable rotational reorganization of the liquid-crystal film and its surface relief, which ultimately causes the rotation of submillimetre-sized particles on the film. 相似文献
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A fundamental tenet of cerebellar learning theories asserts that climbing fibre afferents from the inferior olive provide a teaching signal that promotes the gradual adaptation of movements. Data from several forms of motor learning provide support for this tenet. In pavlovian eyelid conditioning, for example, where a tone is repeatedly paired with a reinforcing unconditioned stimulus like periorbital stimulation, the unconditioned stimulus promotes acquisition of conditioned eyelid responses by activating climbing fibres. Climbing fibre activity elicited by an unconditioned stimulus is inhibited during the expression of conditioned responses-consistent with the inhibitory projection from the cerebellum to inferior olive. Here, we show that inhibition of climbing fibres serves as a teaching signal for extinction, where learning not to respond is signalled by presenting a tone without the unconditioned stimulus. We used reversible infusion of synaptic receptor antagonists to show that blocking inhibitory input to the climbing fibres prevents extinction of the conditioned response, whereas blocking excitatory input induces extinction. These results, combined with analysis of climbing fibre activity in a computer simulation of the cerebellar-olivary system, suggest that transient inhibition of climbing fibres below their background level is the signal that drives extinction. 相似文献
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Fungal spores from the same taxa of fungi that occur in the Pacific Northwest are reported from digestive tracts of31 rodents of 5 genera from the Nothofagus forest of southern Argentina. Mycophagy (fungal feeding) by forest rodents has been well documented in North America (Fogel and Trappe 1978, Maser et al. 1978, Mclntire 1984, and others), Europe (Blaschke and B?umler 1986, Durrieu et al. 1984), and Australia (Malajczuk et al. 1987). The purpose of this note is to report fungi consumed by rodents of the Argentine Andinian Patagonic forest (see Dimitri 1972,McQueen 1977, and Ward 1965 for a discussion of this forest), where mycorrhizal fungi may be an important part of the forest-rodent ecology (Cabrera and Yepes 1960, Pearson 1983, 1948, Pearson and Pearson 1982). 相似文献
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Graham RR Kozyrev SV Baechler EC Reddy MV Plenge RM Bauer JW Ortmann WA Koeuth T González Escribano MF;Argentine Spanish Collaborative Groups Pons-Estel B Petri M Daly M Gregersen PK Martín J Altshuler D Behrens TW Alarcón-Riquelme ME 《Nature genetics》2006,38(5):550-555
Systemic lupus erythematosus (SLE) is a complex autoimmune disease characterized by activation of the type I interferon (IFN) pathway. Here we convincingly replicate association of the IFN regulatory factor 5 (IRF5) rs2004640 T allele with SLE in four independent case-control cohorts (P = 4.4 x 10(-16)) and by family-based transmission disequilibrium test analysis (P = 0.0006). The rs2004640 T allele creates a 5' donor splice site in an alternate exon 1 of IRF5, allowing expression of several unique IRF5 isoforms. We also identify an independent cis-acting variant associated with elevated expression of IRF5 and linked to the exon 1B splice site. Haplotypes carrying the variant associated with elevated expression and lacking the exon 1B donor site do not confer risk of SLE. Thus, a common IRF5 haplotype driving elevated expression of multiple unique isoforms of IRF5 is an important genetic risk factor for SLE, establishing a causal role for type I IFN pathway genes in human autoimmunity. 相似文献
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Stacey SN Manolescu A Sulem P Rafnar T Gudmundsson J Gudjonsson SA Masson G Jakobsdottir M Thorlacius S Helgason A Aben KK Strobbe LJ Albers-Akkers MT Swinkels DW Henderson BE Kolonel LN Le Marchand L Millastre E Andres R Godino J Garcia-Prats MD Polo E Tres A Mouy M Saemundsdottir J Backman VM Gudmundsson L Kristjansson K Bergthorsson JT Kostic J Frigge ML Geller F Gudbjartsson D Sigurdsson H Jonsdottir T Hrafnkelsson J Johannsson J Sveinsson T Myrdal G Grimsson HN Jonsson T von Holst S 《Nature genetics》2007,39(7):865-869
Familial clustering studies indicate that breast cancer risk has a substantial genetic component. To identify new breast cancer risk variants, we genotyped approximately 300,000 SNPs in 1,600 Icelandic individuals with breast cancer and 11,563 controls using the Illumina Hap300 platform. We then tested selected SNPs in five replication sample sets. Overall, we studied 4,554 affected individuals and 17,577 controls. Two SNPs consistently associated with breast cancer: approximately 25% of individuals of European descent are homozygous for allele A of rs13387042 on chromosome 2q35 and have an estimated 1.44-fold greater risk than noncarriers, and for allele T of rs3803662 on 16q12, about 7% are homozygous and have a 1.64-fold greater risk. Risk from both alleles was confined to estrogen receptor-positive tumors. At present, no genes have been identified in the linkage disequilibrium block containing rs13387042. rs3803662 is near the 5' end of TNRC9 , a high mobility group chromatin-associated protein whose expression is implicated in breast cancer metastasis to bone. 相似文献
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José L. Moreno Stuart C. Sealfon Javier González-Maeso 《Cellular and molecular life sciences : CMLS》2009,66(23):3777-3785
Schizophrenia is one of the most common mental illnesses, with hereditary and environmental factors important for its etiology.
All antipsychotics have in common a high affinity for monoaminergic receptors. Whereas hallucinations and delusions usually
respond to typical (haloperidol-like) and atypical (clozapine-like) monoaminergic antipsychotics, their efficacy in improving
negative symptoms and cognitive deficits remains inadequate. In addition, devastating side effects are a common characteristic
of monoaminergic antipsychotics. Recent biochemical, preclinical and clinical findings support group II metabotropic glutamate
receptors (mGluR2 and mGluR3) as a new approach to treat schizophrenia. This paper reviews the status of general knowledge
of mGluR2 and mGluR3 in the psychopharmacology, genetics and neuropathology of schizophrenia 相似文献
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Luiz F L Silveira Gabriel Khattar Stephanie Vaz Vinicius A. Wilson Paula M. Souto José R. M. Mermudes 《Journal of Natural History》2020,54(5-6):275-308
ABSTRACT Fireflies (Coleoptera: Lampyridae) are charismatic insects that have been fruitful model systems in biotechnology. However, lack of information about firefly taxonomy and ecology renders species identification a hard task, especially in the Neotropical region, where fireflies are most diverse. A major gap in the literature on Neotropical fireflies is the lack of knowledge on species’ ecological niches and habitats, which are fundamental aspects for understanding their biology. Here, we provide an annotated checklist of the firefly fauna of the Serra dos Órgãos mountain range (Rio de Janeiro State, Southeastern Brazil), with information on the natural history of each species. We assembled data in three ways: monthly sampling with Malaise traps and active search along an elevational transect from 130 to 2,170 m, over 2 years (2014–2016), extensive field observations, and extracted from historical species records for the Serra dos Órgãos from museum specimens in key collections in Brazil and Europe. We provide a taxonomic key to the genera recorded in the region, and a differential diagnosis for each species, highlighting key references for each taxon. We report 58 species representing 21 genera, making the Serra dos Órgãos one of the richest firefly hotspots on Earth. Most species are restricted to one or two habitat types and/or just one of the regional seasons (warm or cool), and many were only collected either by malaise traps or active search, underlining the importance of sampling different habitat types and seasons, and using different sampling methods when surveying fireflies. Out of the 51 species observed in the field, 49 were active either during the day or the night, although two species – Photuris elliptica and Pyrogaster nigrolineatus – were active in both periods, which is rare in fireflies. 相似文献