7,709 research outputs found

    Who gets credit for AI-generated art?

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    The recent sale of an artificial intelligence (AI)-generated portrait for $432,000 at Christie's art auction has raised questions about how credit and responsibility should be allocated to individuals involved and how the anthropomorphic perception of the AI system contributed to the artwork's success. Here, we identify natural heterogeneity in the extent to which different people perceive AI as anthropomorphic. We find that differences in the perception of AI anthropomorphicity are associated with different allocations of responsibility to the AI system and credit to different stakeholders involved in art production. We then show that perceptions of AI anthropomorphicity can be manipulated by changing the language used to talk about AI—as a tool versus agent—with consequences for artists and AI practitioners. Our findings shed light on what is at stake when we anthropomorphize AI systems and offer an empirical lens to reason about how to allocate credit and responsibility to human stakeholders

    Short-term modulation of distal tubule fluid nitric oxide in vivo by loop NaCl reabsorption

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    Short-term modulation of distal tubule fluid nitric oxide in vivo by loop NaCl reabsorption.BackgroundIntrarenal nitric oxide (NO) production and signaling effects are influenced by NaCl loading. To gain further insight into NO mechanisms we determined whether rat distal tubular fluid (DTF) [NO] and collected NO may acutely change when NaCl loop delivery is altered.MethodsAn NO microelectrode was used to measure real-time DTF [NO] and DT-collected NO. With proximal flow blocked (open system), 150mmol/L NaCl, with and without 10−4 mol/L furosemide was perfused with measurement of loop [Cl] reabsorption. Using a closed system, DTF [NO] was also determined using several different loop perfusates.ResultsIn the open system, perfusion with 40 nL/min of 150mmol/L NaCl to which 10−4 mol/L furosemide was added, DT [NO] and DT-collected NO was approximately twice that measured with perfusion of 150mmol/L NaCl alone, while loop Cl reabsorption decreased by half. In the closed system, perfusion at 10 nL/min of 150mmol/L NaCl + furosemide 10−4 mol/L also induced a significant rise in DTF [NO] and collected NO. Perfusion of 10−3 mol/L S-methyl-L-thiocitrulline (SMTC) with 150mmol/L NaCl, induces a significant drop in DT [NO], but without a significant increase in collected NO. Furthermore, with addition of 10−3 mol/L SMTC to the 150mmol/L NaCl + 10−4 furosemide perfusate, the rise in DT [NO] was prevented. Analysis of covariance showed that flow changes within, or between all groups, had no significant additional effect.ConclusionIn both open and closed loop perfusion systems, 10−4 mol/L furosemide inhibition of NaCl transport stimulates net loop NO emission independent of flow; 10−3 mol/L SMTC + 150mmol/L NaCl reduces DT [NO], but not DT-collected NO. Short-term net NO emission from the entire loop, as collected in distal tubule fluid, increases with inhibition of loop NaCl transport

    Density-Polarization Functional Theory of the response of a periodic insulating solid to an electric field.

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    The response of an infinite, periodic, insulating, solid to an infinitesimally small electric field is investigated in the framework of Density Functional Theory. We find that the applied perturbing potential is not a unique functional of the periodic density change~: it depends also on the change in the macroscopic {\em polarization}. Moreover, the dependence of the exchange-correlation energy on polarization induces an exchange-correlation electric field. These effects are exhibited for a model semiconductor. We also show that the scissor-operator technique is an approximate way of bypassing this polarization dependence.Comment: 11 pages, 1 Fig

    Smooth free involution of HCP3H{\Bbb C}P^3 and Smith conjecture for imbeddings of S3S^3 in S6S^6

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    This paper establishes an equivalence between existence of free involutions on HCP3H{\Bbb C}P^3 and existence of involutions on S6S^6 with fixed point set an imbedded S3S^3, then a family of counterexamples of the Smith conjecture for imbeddings of S3S^3 in S6S^6 are given by known result on HCP3H{\Bbb C}P^3. In addition, this paper also shows that every smooth homotopy complex projective 3-space admits no orientation preserving smooth free involution, which answers an open problem [Pe]. Moreover, the study of existence problem for smooth orientation preserving involutions on HCP3H{\Bbb C}P^3 is completed.Comment: 10 pages, final versio

    Reflection Symmetry and Quantized Hall Resistivity near Quantum Hall Transition

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    We present a direct numerical evidence for reflection symmetry of longitudinal resistivity ρxx\rho_{xx} and quantized Hall resistivity ρxy\rho_{xy} near the transition between ν=1\nu=1 quantum Hall state and insulator, in accord with the recent experiments. Our results show that a universal scaling behavior of conductances, σxx\sigma_{xx} and σxy\sigma_{xy}, in the transition regime decide the reflection symmetry of ρxx\rho_{xx} and quantization of ρxy\rho_{xy}, independent of particle-hole symmetry. We also find that in insulating phase away from the transition region ρxy\rho_{xy} deviates from the quantization and diverges with ρxx\rho_{xx}.Comment: 3 pages, 4 figures; figure 4 is replace

    Second harmonic generation in SiC polytypes

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    LMTO calculations are presented for the frequency dependent second harmonic generation (SHG) in the polytypes 2H, 4H, 6H, 15R and 3C of SiC. All independent tensor components are calculated. The spectral features and the ratios of the 333 to 311 tensorial components are studied as a function of the degree of hexagonality. The relationship to the linear optical response and the underlying band structure are investigated. SHG is suggested to be a sensitive tool for investigating the near band edge interband excitations.Comment: 12 pages, 10 figure

    Operation of a quantum dot in the finite-state machine mode: single-electron dynamic memory

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    A single electron dynamic memory is designed based on the non-equilibrium dynamics of charge states in electrostatically-defined metallic quantum dots. Using the orthodox theory for computing the transfer rates and a master equation, we model the dynamical response of devices consisting of a charge sensor coupled to either a single and or a double quantum dot subjected to a pulsed gate voltage. We show that transition rates between charge states in metallic quantum dots are characterized by an asymmetry that can be controlled by the gate voltage. This effect is more pronounced when the switching between charge states corresponds to a Markovian process involving electron transport through a chain of several quantum dots. By simulating the dynamics of electron transport we demonstrate that the quantum box operates as a finite-state machine that can be addressed by choosing suitable shapes and switching rates of the gate pulses. We further show that writing times in the ns range and retention memory times six orders of magnitude longer, in the ms range, can be achieved on the double quantum dot system using experimentally feasible parameters thereby demonstrating that the device can operate as a dynamic single electron memory.Comment: 18 pages, 8 figure

    Delocalization of electrons in a Random Magnetic Field

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    Delocalization problem for a two-dimensional non-interacting electron system is studied under a random magnetic field. With the presence of a random magnetic field, the Hall conductance carried by each eigenstate can become nonzero and quantized in units of e2/he^2/h. Extended states are characterized by nonzero Hall conductance, and by studying finite-size scaling of the density of extended states, an insulator-metal phase transition is revealed. The metallic phase is found at the center of energy band which is separated from the localized states at the band tails by critical energies ±Ec\pm E_c. Both localization exponent and the critical energy EcE_c are shown to be dependent on the strength of random magnetic field.Comment: 9 pages, Revtex, 3 figures available upon reques

    Photoelasticity of crystalline and amorphous silica from first principles

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    Based on density-functional perturbation theory we have computed from first principles the photoelastic tensor of few crystalline phases of silica at normal conditions and high pressure (quartz, α\alpha-cristobalite, β\beta-cristobalite) and of models of amorphous silica (containig up to 162 atoms), obtained by quenching from the melt in combined classical and Car-Parrinello molecular dynamics simulations. The computational framework has also been checked on the photoelastic tensor of crystalline silicon and MgO as prototypes of covalent and ionic systems. The agreement with available experimental data is good. A phenomenological model suitable to describe the photoelastic properties of different silica polymorphs is devised by fitting on the ab-initio data.Comment: ten figure
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