666 research outputs found
Theory of spin blockade, charge ratchet effect, and thermoelectrical behavior in serially coupled quantum-dot system
The charge transport of a serially coupled quantum dots (SCQD) connected to
the metallic electrodes is theoretically investigated in the Coulomb blockade
regime. A closed-form expression for the tunneling current of SCQD in the
{\color{red} weak interdot hopping} limit is obtained by solving an extended
two-site Hubbard model via the Green's function method. We use this expression
to investigate spin current rectification, negative differential conductance,
and coherent tunneling in the nonlinear response regime. The current
rectification arising from the space symmetry breaking of SCQD is suppressed by
increasing temperature. The calculation of SCQD is extended to the case of
multiple parallel SCQDs for studying the charge ratchet effect and SCQD with
multiple levels. In the linear response regime, the functionalities of spin
filter and low-temperature current filter are demonstrated to coexist in this
system. It is further demonstrated that two-electron spin singlet and triplet
states can be readily resolved from the measurement of Seebeck coefficient
rather than that of electrical conductance.Comment: 11 pages, 9 figures. Revised argument, results unchanged, added
reference
Structural insights into regulation of nuclear receptors by ligands
Nuclear receptors are DNA-binding transcription factors, the transcriptional function of many of which depends on the binding of ligands, a feature that distinguishes nuclear receptors from other transcription factors. This review will summarize recent advances in our knowledge of the interaction between selected nuclear receptors and their cognate ligands
Tunable Kondo effect in a single donor atom
The Kondo effect has been observed in a single gate-tunable atom. The
measurement device consists of a single As dopant incorporated in a Silicon
nanostructure. The atomic orbitals of the dopant are tunable by the gate
electric field. When they are tuned such that the ground state of the atomic
system becomes a (nearly) degenerate superposition of two of the Silicon
valleys, an exotic and hitherto unobserved valley Kondo effect appears.
Together with the regular spin Kondo, the tunable valley Kondo effect allows
for reversible electrical control over the symmetry of the Kondo ground state
from an SU(2)- to an SU(4) -configuration.Comment: 10 pages, 8 figure
Eliciting a predatory response in the eastern corn snake (Pantherophis guttatus) using live and inanimate sensory stimuli: implications for managing invasive populations
North America's Eastern corn snake (Pantherophis guttatus) has been introduced to several islands throughout the Caribbean and Australasia where it poses a significant threat to native wildlife. Invasive snake control programs often involve trapping with live bait, a practice that, as well as being costly and labour intensive, raises welfare and ethical concerns. This study assessed corn snake response to live and inanimate sensory stimuli in an attempt to inform possible future trapping of the species and the development of alternative trap lures. We exposed nine individuals to sensory cues in the form of odour, visual, vibration and combined stimuli and measured the response (rate of tongue-flick [RTF]). RTF was significantly higher in odour and combined cues treatments, and there was no significant difference in RTF between live and inanimate cues during odour treatments. Our findings suggest chemical cues are of primary importance in initiating predation and that an inanimate odour stimulus, absent of simultaneous visual and vibratory cues, is a potential low-cost alternative trap lure for the control of invasive corn snake populations
- …