Self-stimulation alters human sensory brain responses   总被引：3，自引：0，他引：3  

E W Schafer  M M Marcus 《Science (New York, N.Y.)》1973,181(95):175-177

Human electrocortical potentials evoked by self-administered auditory and visual stimuli manifest much smaller amplitude and faster poststimulus timing than do average brain responses evoked by identical machine-delivered stimuli. Auditory evoked potentials show this "self-stimulation effect" to a greater degree than do visual responses. For visual evoked potentials, the effect appears greater at the vertex association area than over the occipital cortex. Individual differences in the magnitude of the "self-stimutlation effect" relate to level of intelligence.  相似文献   

Control of early viral and bacterial distribution and disease by natural antibodies     

Ochsenbein AF  Fehr T  Lutz C  Suter M  Brombacher F  Hengartner H  Zinkernagel RM 《Science (New York, N.Y.)》1999,286(5447):2156-2159

Natural antibodies are often dismissed from immunological analysis as "background," but they may play an important role in conferring immunity against infections. In antibody-free mice infected with various viruses or with Listeria monocytogenes, viral or bacterial titers in peripheral organs, including the kidney and brain, were 10 to 100 times greater than in antibody-competent mice (and enhanced their susceptibility to some infections), and titers in secondary lymphoid organs were 10 to 100 times lower than in antibody-competent mice. Thus, natural antibodies play a crucial role by preventing pathogen dissemination to vital organs and by improving immunogenicity through enhanced antigen-trapping in secondary lymphoid organs.  相似文献   

Target-set and response-set interaction: implications for models of human information processing     

Egeth H  Marcus N  Bevan W 《Science (New York, N.Y.)》1972,176(4042):1447-1448

In binary character-classification tasks, reaction time generally has been reported to increase substantially with the number of target elements. However, when the targets formed a familiar set and subjects were not required to make explicit "no" responses, reaction time did not increase significantly as the target set increased in size from one to three.  相似文献   

Quantum Hall effect in a gate-controlled p-n junction of graphene   总被引：1，自引：0，他引：1  

Williams JR  Dicarlo L  Marcus CM 《Science (New York, N.Y.)》2007,317(5838):638-641

The unique band structure of graphene allows reconfigurable electric-field control of carrier type and density, making graphene an ideal candidate for bipolar nanoelectronics. We report the realization of a single-layer graphene p-n junction in which carrier type and density in two adjacent regions are locally controlled by electrostatic gating. Transport measurements in the quantum Hall regime reveal new plateaus of two-terminal conductance across the junction at 1 and 32 times the quantum of conductance, e(2)/h, consistent with recent theory. Beyond enabling investigations in condensed-matter physics, the demonstrated local-gating technique sets the foundation for a future graphene-based bipolar technology.  相似文献   

An adiabatic quantum electron pump     

Switkes M  Marcus CM  Campman K  Gossard AC 《Science (New York, N.Y.)》1999,283(5409):1905-1908

A quantum pumping mechanism that produces dc current or voltage in response to a cyclic deformation of the confining potential in an open quantum dot is reported. The voltage produced at zero current bias is sinusoidal in the phase difference between the two ac voltages deforming the potential and shows random fluctuations in amplitude and direction with small changes in external parameters such as magnetic field. The amplitude of the pumping response increases linearly with the frequency of the deformation. Dependencies of pumping on the strength of the deformations, temperature, and breaking of time-reversal symmetry were also investigated.  相似文献   

Apparent production of 2 types of antibdoies by a single cell     

J G Michael  R Marcus 《Science (New York, N.Y.)》1968,159(820):1247-1249

Immunization of mice with bacterial, sheep red cells coated with antigen resulted in apparent production of antibody-forming plaques with specificities for both hemolysis and bactericidal activity. The secondary response for production of these bifunctional types of plaques could be induced by red blood cells or bacteria alone. A significant mutual suppression of immune response between the two immunizing agents was observed.  相似文献   

Snares Awaiting the American Scientist     

Marcus JK 《Science (New York, N.Y.)》1953,117(3045):507-509

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Speeding up the EPA review process     

Peacock M 《Science (New York, N.Y.)》2007,316(5821):53

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A proposal for a Decade of the Mind initiative     

Albus JS  Bekey GA  Holland JH  Kanwisher NG  Krichmar JL  Mishkin M  Modha DS  Raichle ME  Shepherd GM  Tononi G 《Science (New York, N.Y.)》2007,317(5843):1321

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NIOSH and the CDC reorganization     

Key MM  Robbins A  Millar JD  Rosenstock L 《Science (New York, N.Y.)》2004,305(5684):607

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