Revisiting the taxonomic impediment     

de Carvalho MR  Bockmann FA  Amorim DS  de Vivo M  de Toledo-Piza M  Menezes NA  de Figueiredo JL  Castro RM  Gill AC  McEachran JD  Compagno LJ  Schelly RC  Britz R  Lundberg JG  Vari RP  Nelson G 《Science (New York, N.Y.)》2005,307(5708):353

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Infectious behavior in a parasitoid     

Varaldi J  Fouillet P  Ravallec M  López-Ferber M  Boulétreau M  Fleury F 《Science (New York, N.Y.)》2003,302(5652):1930

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Contribution of the Patagonia Icefields of South America to sea level rise   总被引：2，自引：0，他引：2  

Rignot E  Rivera A  Casassa G 《Science (New York, N.Y.)》2003,302(5644):434-437

Digital elevation models of the Northern and Southern Patagonia Icefields of South America generated from the 2000 Shuttle Radar Topography Mission were compared with earlier cartography to estimate the volume change of the largest 63 glaciers. During the period 1968/1975-2000, these glaciers lost ice at a rate equivalent to a sea level rise of 0.042 +/- 0.002 millimeters per year. In the more recent years 1995-2000, average ice thinning rates have more than doubled to an equivalent sea level rise of 0.105 +/- 0.011 millimeters per year. The glaciers are thinning more quickly than can be explained by warmer air temperatures and decreased precipitation, and their contribution to sea level per unit area is larger than that of Alaska glaciers.  相似文献   

Mass mortality of krill caused by parasitoid ciliates     

Gómez-Gutiérrez J  Peterson WT  De Robertis A  Brodeur RD 《Science (New York, N.Y.)》2003,301(5631):339

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Comment on "Drought-induced reduction in global terrestrial net primary production from 2000 through 2009"     

Samanta A  Costa MH  Nunes EL  Vieira SA  Xu L  Myneni RB 《Science (New York, N.Y.)》2011,333(6046):1093; author reply 1093

Zhao and Running (Reports, 20 August 2010, p. 940) reported a reduction in global terrestrial net primary production (NPP) from 2000 through 2009. We argue that the small trends, regional patterns, and interannual variations that they describe are artifacts of their NPP model. Satellite observations of vegetation activity show no statistically significant changes in more than 85% of the vegetated lands south of 70°N during the same 2000 to 2009 period.  相似文献   

Preserved feedforward but impaired top-down processes in the vegetative state     

Boly M  Garrido MI  Gosseries O  Bruno MA  Boveroux P  Schnakers C  Massimini M  Litvak V  Laureys S  Friston K 《Science (New York, N.Y.)》2011,332(6031):858-862

Frontoparietal cortex is involved in the explicit processing (awareness) of stimuli. Frontoparietal activation has also been found in studies of subliminal stimulus processing. We hypothesized that an impairment of top-down processes, involved in recurrent neuronal message-passing and the generation of long-latency electrophysiological responses, might provide a more reliable correlate of consciousness in severely brain-damaged patients, than frontoparietal responses. We measured effective connectivity during a mismatch negativity paradigm and found that the only significant difference between patients in a vegetative state and controls was an impairment of backward connectivity from frontal to temporal cortices. This result emphasizes the importance of top-down projections in recurrent processing that involve high-order associative cortices for conscious perception.  相似文献   

Spontaneous cortical activity reveals hallmarks of an optimal internal model of the environment     

Berkes P  Orbán G  Lengyel M  Fiser J 《Science (New York, N.Y.)》2011,331(6013):83-87

The brain maintains internal models of its environment to interpret sensory inputs and to prepare actions. Although behavioral studies have demonstrated that these internal models are optimally adapted to the statistics of the environment, the neural underpinning of this adaptation is unknown. Using a Bayesian model of sensory cortical processing, we related stimulus-evoked and spontaneous neural activities to inferences and prior expectations in an internal model and predicted that they should match if the model is statistically optimal. To test this prediction, we analyzed visual cortical activity of awake ferrets during development. Similarity between spontaneous and evoked activities increased with age and was specific to responses evoked by natural scenes. This demonstrates the progressive adaptation of internal models to the statistics of natural stimuli at the neural level.  相似文献   

套作玉米产量与栽培密度及氮磷钾肥施用量的关系     

马俊梅艳  吴嵩梁黔云  范厚明罗新颖 陈森林 《勤云标准版测试》2005,(4)

采用二次回归通用旋转组合设计方法试验,以马铃薯套作玉米产量为目标,以套作的玉米密度、氮、磷、钾肥施用量为探讨对象,建立了套作玉米产量与密度、氮、磷、钾肥施用量间关系的数学模型(y=7396.05-536.7x1 129.0x2 135.6x3 104.7x4-19.65x1x2-5.4x1x3 147.75x1x4 165.15x2x3-86.55x2x4 113.7x3x4-478.8x12-407.7x22-446.25x32-450.3x42),通过模拟寻优,提出了玉米产量≥6750.00kg/hm2的综合农艺栽培方案(玉米密度44856-51135株/hm2,平均48000株/hm2;N279.30-350.70kg/hm2,平均315.00kg/hm2;P2O5189.00-231.00kg/hm2,平均210.00kg/hm2;K2O167.70-222.30kg/hm2,平均195.00kg/hm2。N:P:K=1:0.667:0.619)。  相似文献   

Airborne lead and carbon monoxide at 45th Street, New York City   总被引：1，自引：0，他引：1  

J L Bové  S Siebenberg 《Science (New York, N.Y.)》1970,167(920):986-987

Daily business-day traffic determines the diurnal lead concentration as well as diurnal carbon monoxide concentration. Daily averages of 7.5 micrograms per cubic meter for lead and 13 parts per million of carbon monoxide were found for the 10-week period of the study. Correlations were demonstrated for lead and traffic and lead and carbon monoxide.  相似文献   

Scientists and the Venezuelan crisis     

Jaffe K  Di Polo R  Cardier J  Rios R  Utrera R  Rodriguez M  Zoppi LB  Rojas AM  Ponte A  Scharifker B  Bemporad M;Board of Directors  Venezuelan Association for the Advancement of Science  Caracas 《Science (New York, N.Y.)》2003,299(5610):1184

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