rf-electrometer using a carbon nanotube resonant tunneling transistor

We have studied resonant tunneling transistors (RTT) made of single-walled carbon nanotube quantum dots in the Fabry–Pérot regime. We show sensitivity to input charge as high as 5×10 exp −6 e/Hz1/2 with a carrier frequency of 719 MHz at 4.2 K. This result is comparable to the best values of charge sensitivity so far reported for radio frequency single electron transistors (rf-SET). Unlike SETs, whose operating temperature is limited as Coulomb blockade vanishes as 1/T, a RTT can operate at higher temperatures, since the dephasing length lϕ∝1/T exp 2/exp 3.Peer reviewe

Liberating Intelligent Machines with Financial Instruments

In science fiction, Isaac Asimov's three laws of robotics, as presented in his novel I, Robot, are the classical starting point for machine responsibility analysis.1 Machine ethics research has widely followed Asimov's example2. Murphy and Woods3 propose alternative laws inspired by Asimov's original laws that emphasize a developer’s view on the ethics of robotics. In these works, machine responsibility is presented from the ethical point of view, but product liability issues are mostly absent, as is legal analysis. The present state of robot legal liability issues is to some extent described in existing literature.4 This paper addresses responsible robotics from a legal perspective. However, instead of focusing on ethical considerations elaborated in philosophy and Artificial Intelligence (AI)5 communities6, the legal liability risks related to inherently error-prone intelligent machines are considered and a solution combining legal and economical components is proposed. Because of the technological difficulties in creating perfectly functioning machines and the cognitive element inherent in intelligent machines and machine interactions, we propose a new kind of legal approach, i.e. a financial instrument liberating the machine. In this framework, a machine can become an ultimate machine by emancipating itself from its manufacturer/owner/operator. This can be achieved through the creation of a legal framework around this ultimate machine that in itself has economic value. We start this article by assessing the liability risks related to intelligent machines. Currently, the manufacturer or operator is held liable depending on the circumstances. Thereafter we will examine the management of the risks by technical and legal means, i.e. by means of liability stocks liberating the machine. The article relates to the European context. However, the solution can easily be adapted to other jurisdictions

Multiple Signals Converge on a Differentiation MAPK Pathway

An important emerging question in the area of signal transduction is how information from different pathways becomes integrated into a highly coordinated response. In budding yeast, multiple pathways regulate filamentous growth, a complex differentiation response that occurs under specific environmental conditions. To identify new aspects of filamentous growth regulation, we used a novel screening approach (called secretion profiling) that measures release of the extracellular domain of Msb2p, the signaling mucin which functions at the head of the filamentous growth (FG) MAPK pathway. Secretion profiling of complementary genomic collections showed that many of the pathways that regulate filamentous growth (RAS, RIM101, OPI1, and RTG) were also required for FG pathway activation. This regulation sensitized the FG pathway to multiple stimuli and synchronized it to the global signaling network. Several of the regulators were required for MSB2 expression, which identifies the MSB2 promoter as a target “hub” where multiple signals converge. Accessibility to the MSB2 promoter was further regulated by the histone deacetylase (HDAC) Rpd3p(L), which positively regulated FG pathway activity and filamentous growth. Our findings provide the first glimpse of a global regulatory hierarchy among the pathways that control filamentous growth. Systems-level integration of signaling circuitry is likely to coordinate other regulatory networks that control complex behaviors