High impulsivity predicts the switch to compulsive cocaine-taking     

Belin D  Mar AC  Dalley JW  Robbins TW  Everitt BJ 《Science (New York, N.Y.)》2008,320(5881):1352-1355

Both impulsivity and novelty-seeking have been suggested to be behavioral markers of the propensity to take addictive drugs. However, their relevance for the vulnerability to compulsively seek and take drugs, which is a hallmark feature of addiction, is unknown. We report here that, whereas high reactivity to novelty predicts the propensity to initiate cocaine self-administration, high impulsivity predicts the development of addiction-like behavior in rats, including persistent or compulsive drug-taking in the face of aversive outcomes. This study shows experimental evidence that a shift from impulsivity to compulsivity occurs during the development of addictive behavior, which provides insights into the genesis and neural mechanisms of drug addiction.  相似文献   

Number theory. Simple recipe creates acid test for primes     

Cipra B 《Science (New York, N.Y.)》2002,297(5584):1105-1106

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MathFest 2008. Taking the edge off     

Cipra B 《Science (New York, N.Y.)》2008,321(5894):1283

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A high-resolution paleoclimate record spanning the past 25,000 years in southern East Africa     

Johnson TC  Brown ET  McManus J  Barry S  Barker P  Gasse F 《Science (New York, N.Y.)》2002,296(5565):113-132

High-resolution profiles of the mass accumulation rate of biogenic silica and other geochemical proxies in two piston cores from northern Lake Malawi provide a climate signal for this part of tropical Africa spanning the past 25,000 years. The biogenic silica mass accumulation rate was low during the relatively dry late Pleistocene, when the river flux of silica to the lake was suppressed. Millennial-scale fluctuations, due to upwelling intensity, in the late Pleistocene climate of the Lake Malawi basin appear to have been closely linked to the Northern Hemisphere climate until 11 thousand years ago. Relatively cold conditions in the Northern Hemisphere coincided with more frequent north winds over the Malawi basin, perhaps resulting from a more southward migration of the Intertropical Convergence Zone.  相似文献   

A mule cloned from fetal cells by nuclear transfer   总被引：1，自引：0，他引：1  

Woods GL  White KL  Vanderwall DK  Li GP  Aston KI  Bunch TD  Meerdo LN  Pate BJ 《Science (New York, N.Y.)》2003,301(5636):1063

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Identifying autism loci and genes by tracing recent shared ancestry   总被引：2，自引：0，他引：2  

Morrow EM  Yoo SY  Flavell SW  Kim TK  Lin Y  Hill RS  Mukaddes NM  Balkhy S  Gascon G  Hashmi A  Al-Saad S  Ware J  Joseph RM  Greenblatt R  Gleason D  Ertelt JA  Apse KA  Bodell A  Partlow JN  Barry B  Yao H  Markianos K  Ferland RJ  Greenberg ME  Walsh CA 《Science (New York, N.Y.)》2008,321(5886):218-223

To find inherited causes of autism-spectrum disorders, we studied families in which parents share ancestors, enhancing the role of inherited factors. We mapped several loci, some containing large, inherited, homozygous deletions that are likely mutations. The largest deletions implicated genes, including PCDH10 (protocadherin 10) and DIA1 (deleted in autism1, or c3orf58), whose level of expression changes in response to neuronal activity, a marker of genes involved in synaptic changes that underlie learning. A subset of genes, including NHE9 (Na+/H+ exchanger 9), showed additional potential mutations in patients with unrelated parents. Our findings highlight the utility of "homozygosity mapping" in heterogeneous disorders like autism but also suggest that defective regulation of gene expression after neural activity may be a mechanism common to seemingly diverse autism mutations.  相似文献   

Lessons from SARS     

Bloom BR 《Science (New York, N.Y.)》2003,300(5620):701

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International decade of climatology     

Nichols H  Andrews JT  Barry RG  Ives JD 《Science (New York, N.Y.)》1976,193(4254):633-634

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Nervous system targets of RNA editing identified by comparative genomics     

Hoopengardner B  Bhalla T  Staber C  Reenan R 《Science (New York, N.Y.)》2003,301(5634):832-836

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The brain of LB1, Homo floresiensis     

Falk D  Hildebolt C  Smith K  Morwood MJ  Sutikna T  Brown P  Jatmiko  Saptomo EW  Brunsden B  Prior F 《Science (New York, N.Y.)》2005,308(5719):242-245

The brain of Homo floresiensis was assessed by comparing a virtual endocast from the type specimen (LB1) with endocasts from great apes, Homo erectus, Homo sapiens, a human pygmy, a human microcephalic, specimen number Sts 5 (Australopithecus africanus), and specimen number WT 17000 (Paranthropus aethiopicus). Morphometric, allometric, and shape data indicate that LB1 is not a microcephalic or pygmy. LB1's brain/body size ratio scales like that of an australopithecine, but its endocast shape resembles that of Homo erectus. LB1 has derived frontal and temporal lobes and a lunate sulcus in a derived position, which are consistent with capabilities for higher cognitive processing.  相似文献