Evaluation of Musical Creativity and Musical Metacreation Systems

The field of computational creativity, including musical metacreation, strives to develop artificial systems that are capable of demonstrating creative behavior or producing creative artefacts. But the claim of creativity is often assessed, subjectively only on the part of the researcher and not objectively at all. This article provides theoretical motivation for more systematic evaluation of musical metacreation and computationally creative systems and presents an overview of current methods used to assess human and machine creativity that may be adapted for this purpose. In order to highlight the need for a varied set of evaluation tools, a distinction is drawn among three types of creative systems: those that are purely generative, those that contain internal or external feedback, and those that are capable of reflection and self-reflection. To address the evaluation of each of these aspects, concrete examples of methods and techniques are suggested to help researchers (1) evaluate their systems' creative process and generated artefacts, and test their impact on the perceptual, cognitive, and affective states of the audience, and (2) build mechanisms for reflection into the creative system, including models of human perception and cognition, to endow creative systems with internal evaluative mechanisms to drive self-reflective processes. The first type of evaluation can be considered external to the creative system and may be employed by the researcher to both better understand the efficacy of their system and its impact and to incorporate feedback into the system. Here we take the stance that understanding human creativity can lend insight to computational approaches, and knowledge of how humans perceive creative systems and their output can be incorporated into artificial agents as feedback to provide a sense of how a creation will impact the audience. The second type centers around internal evaluation, in which the system is able to reason about its own behavior and generated output. We argue that creative behavior cannot occur without feedback and reflection by the creative/metacreative system itself. More rigorous empirical testing will allow computational and metacreative systems to become more creative by definition and can be used to demonstrate the impact and novelty of particular approaches

Pyridazino-pyrrolo-quinoxalinium salts as highly potent and selective leishmanicidal agents targeting trypanothione reductase

Fifteen pyridazino-pyrrolo-quinoxalinium salts were synthesized and tested for their antiprotozoal activity against Leishmania infantum amastigotes. Eleven of them turned out to be leishmanicidal, with EC values in the nanomolar range, and displayed low toxicity against the human THP-1 cell line. Selectivity indices for these compounds range from 10 to more than 1000. Compounds 3b and 3f behave as potent inhibitors of the oxidoreductase activity of the essential enzyme trypanothione disulfide reductase (TryR). Interestingly, binding of 3f is not affected by high trypanothione concentrations, as revealed by the noncompetitive pattern of inhibition observed when tested in the presence of increasing concentrations of this substrate. Furthermore, when analyzed at varying NADPH concentrations, the characteristic pattern of hyperbolic uncompetitive inhibition supports the view that binding of NADPH to TryR is a prerequisite for inhibitor-protein association. Similar to other TryR uncompetitive inhibitors for NADPH, 3f is responsible for TryR-dependent reduction of cytochrome c in a reaction that is typically inhibited by superoxide dismutase.This research was funded by the Spanish MICINN (Projects PID2019-104070RB-C22 and PCTQ2017-85263-R), the Comunidad de Madrid (Project PLATESA2-CM ref S-2018/BAA-4370 and NOV- ELREN, B2017/BMD-3751) and the Instituto de Salud Carlos III (FEDER funds, RETIC REDINREN RD16/0009/0015). The University of Alcalá and the Spanish Ministry for Culture and Education are gratefully acknowledged for the predoctoral fellowship (FPU16/1647) to J. G.-M. The University of Alcalá is also gratefully acknowledged for the FPU grants to P. S. A. and J. C. G.-S. and the postdoctoral fellowship to H. d. L