A Rigorous Approach to High-Resolution Entropy-Constrained Vector Quantization

The nonnegativity of relative entropy implies that the differential entropy of a random vector X with probability density function (pdf) f is upper-bounded by -E[log g(X)]for any arbitrary pdf g. Using this inequality with a cleverly chosen g, we derive a lower bound on the asymptotic excess rate of entropy-constrained vector quantization for d-dimensional sources and rth-power distortion, where the asymptotic excess rate is defined as the difference between the smallest output entropy of a vector quantizer satisfying the distortion constraint and the rate-distortion function in the limit as the distortion tends to zero. Specialized to the one-dimensional case, this lower bound coincides with the asymptotic excess rate achieved by a uniform quantizer, thereby recovering the result by Gish and Pierce that uniform quantizers are asymptotically optimal as the allowed distortion tends to zero. Furthermore, in the one-dimensional case, the derivation of the lower bound reveals a necessary condition for a sequence of quantizers to be asymptotically optimal. This condition implies that any sequence of asymptotically optimal almost-regular quantizers must converge to a uniform quantizer as the distortion tends to zero. While the obtained lower bound itself is not novel, to the best of our knowledge, we present the first rigorous derivation that follows the direct approach by Gish and Pierce without resorting to heuristic high-resolution approximations commonly found in the quantization literature. Furthermore, our derivation holds for all d-dimensional sources having finite differential entropy and whose integer part has finite entropy. In contrast to Gish and Pierce, we do not require additional constraints on the continuity or decay of the source pdf.This work has received funding from the European Research Council (ERC) under the European Union’s Horizon 2020 research and innovation programme (grant agreement number 714161), from the 7th European Union Framework Programme under Grant 333680, from the Ministerio de Economía y Competitividad of Spain under Grants TEC2013-41718-R, RYC-2014-16332, IJCI-2015-27020, TEC2015-69648-REDC, and TEC2016-78434-C3-3-R (AEI/FEDER, EU), and from the Comunidad de Madrid under Grant S2103/ICE-2845. The material in this paper was presented in part at the 2016 IEEE International Symposium on Information Theory, Barcelona, Spain, July 2016

Generalized perfect codes for symmetric classical-quantum channels

We define a new family of codes for symmetric classical-quantum channels and establish their optimality. To this end, we extend the classical notion of generalized perfect and quasi-perfect codes to channels defined over some finite dimensional complex Hilbert output space. The resulting optimality conditions depend on the channel considered and on an auxiliary state defined on the output space of the channel. For certain N-qubit classical-quantum channels, we show that codes based on a generalization of Bell states are quasi-perfect and, therefore, they feature the smallest error probability among all codes of the same blocklength and cardinality.This work was supported in part by the European Research Council (ERC) under Grant 714161; in part by the Agencia Estatal de Investigación, Ministerio de Ciencia e Innovación, the Spanish Government, under Grant RED2018-102668-T, Grant PID2019-104958RB-C41, and Grant PID2020-116683GB-C21; and in part by the Catalan Government, within the ERDF Program of Catalunya, under Grant 2017 SGR 578 AGAUR and Grant 001-P001644 QuantumCAT.Peer ReviewedPostprint (author's final draft

DNA assembly standards: Setting the low-level programming code for plant biotechnology

[EN] Synthetic Biology is defined as the application of engineering principles to biology. It aims to increase the speed, ease and predictability with which desirable changes and novel traits can be conferred to living cells. The initial steps in this process aim to simplify the encoding of new instructions in DNA by establishing low-level programming languages for biology. Together with advances in the laboratory that allow multiple DNA molecules to be efficiently assembled together into a desired order in a single step, this approach has simplified the design and assembly of multigene constructs and has even facilitated the automated construction of synthetic chromosomes. These advances and technologies are now being applied to plants, for which there are a growing number of software and wetware tools for the design, construction and delivery of DNA molecules and for the engineering of endogenous genes. Here we review the efforts of the past decade that have established synthetic biology workflows and tools for plants and discuss the constraints and bottlenecks of this emerging field.Marta Vazquez-Vilar is funded by Wageningen University & Research. Diego Orzaez is funded by the Spanish Ministry of Economy and Competitiveness [grant number BIO2016-78601-R]. Nicola Patron is funded by the UK Biotechnological and Biological Sciences Research Council (BBSRC) and Engineering and Physics Research Council (EPSRC)Synthetic Biology for Growth programme [OpenPlant Synthetic Biology Research Centre, grant number BB/L0I4130/1], and by the Earlham DNA Foundry [grant number BB/CCG1720/1].Vázquez-Vilar, M.; Orzáez Calatayud, DV.; Patron, N. (2018). DNA assembly standards: Setting the low-level programming code for plant biotechnology. Plant Science. 273:33-41. https://doi.org/10.1016/j.plantsci.2018.02.024S334127

CRISPR-Cas12a genome editing at the whole-plant level using two compatible RNA virus vectors

[EN] The use of viral vectors that can replicate and move systemically through the host plant to deliver bacterial CRISPR components enables genome editing at the whole-plant level and avoids the requirement for labor-intensive stable transformation. However, this approach usually relies on previously transformed plants that stably express a CRISPR-Cas nuclease. Here, we describe successful DNA-free genome editing of Nicotiana benthamiana using two compatible RNA virus vectors derived from tobacco etch virus (TEV; genus Potyvirus) and potato virus X (PVX; genus Potexvirus), which replicate in the same cells. The TEV and PVX vectors respectively express a Cas12a nuclease and the corresponding guide RNA. This novel two-virus vector system improves the toolbox for transformation-free virus-induced genome editing in plants and will advance efforts to breed more nutritious, resistant, and productive crops.This research was supported by grants BIO2017-83184-R and PID2019-108203RB-I00 from the Ministerio de Ciencia e Innovacion (Spain) through the Agencia Estatal de Investigacion (co-financed by the European Regional Development Fund) and H2020-760331 Newcotiana from the European Commission. M.U. andM.V.-V. are the recipients of fellowships FPU17/05503 from the Ministerio de Ciencia e Innovacion (Spain) and APOSTD/2020/096 from the Generalitat Valenciana (Spain), respectivelyUranga, M.; Vázquez-Vilar, M.; Orzáez Calatayud, DV.; Daròs, J. (2021). CRISPR-Cas12a genome editing at the whole-plant level using two compatible RNA virus vectors. The CRISPR Journal. 4(5):1-9. https://doi.org/10.1089/crispr.2021.0049194

Fenton and Photo-Fenton Nanocatalysts Revisited from the Perspective of Life Cycle Assessment

This study provides an overview of the environmental impacts associated with the production of different magnetic nanoparticles (NPs) based on magnetite (Fe3O4), with a potential use as heterogeneous Fenton or photo-Fenton catalysts in wastewater treatment applications. The tendency of Fe3O4 NPs to form aggregates in water makes necessary their decoration with stabilizing agents, in order to increase their catalytic activity. Different stabilizing agents were considered in this study: poly(acrylic acid) (PAA), polyethylenimine (PEI) and silica (SiO2), as well as the immobilization of the magnetite-based catalysts in a mesoporous silica matrix, SBA-15. In the case of photo-Fenton catalysts, combinations of magnetite NPs with semiconductors were evaluated, so that magnetic recovery of the nanomaterials is possible, thus allowing a safe discharge free of NPs. The results of this study suggest that magnetic nanoparticles coated with PEI or PAA were the most suitable option for their applications in heterogeneous Fenton processes, while ZnO-Fe3O4 NPs provided an interesting approach in photo-Fenton. This work showed the importance of identifying the relevance of nanoparticle production strategy in the environmental impacts associated with their useThis research was supported by two projects granted by Spanish Ministry of Science and Innovation: MODENA Project CTQ2016-79461-R and CLUSTERCAT Project MAT2015-67458-P, and Fundación Ramón Areces, Spain (Project CIVP18A3940). The authors belong to the Galician Competitive Research Groups ED431C-2017/22 and ED431C-2017/29 and CRETUS InstituteS

Saddlepoint Approximations for Noncoherent Single-Antenna Rayleigh Block-Fading Channels

Proceeding of: 2019 IEEE International Symposium on Information Theory (ISIT), 7-12 July 2019, Paris, FranceThis paper presents saddlepoint approximations of state-of-the-art converse and achievability bounds for noncoherent, single-antenna, Rayleigh block-fading channels. These approximations can be calculated efficiently and are shown to be accurate for SNR values as small as 0 dB, blocklengths of 168 channel uses or more, and when the channel's coherence interval is not smaller than two. It is demonstrated that the derived approximations recover both the normal approximation and the reliability function of the channel.A. Lancho, G. Vázquez-Vilar and T. Koch have received funding from the European Research Council (ERC) under the European Union’s Horizon 2020 research and innovation programme (714161), the Spanish Ministerio de Economía y Competitividad (RYC-2014-16332, TEC2016-78434-C3-3-R (AEI/FEDER, EU) and IJCI2015-27020), the Spanish Ministerio de Educación, Cultura y Deporte (FPU014/01274), and the Comunidad de Madrid (S2103/ICE-2845). G. Durisi and J. Östman have been supported by the Swedish Research Council under Grants 2016-03293 and 2014-6066

Depresión en personas mayores: Aplicación del método de Bayes

En el presente trabajo se realiza, en primer lugar, una descripción de la sintomatología depresiva en general y en la población de personas mayores en particular. A su vez, se exponen una serie de variables que podrían estar relacionadas con la presencia o ausencia de esta sintomatología. Estas variables son edad, género, estado civil, deterioro cognitivo, dependencia física, estilo de afrontamiento y bienestar psicológico. A partir de estas variables, se realiza un análisis probabilístico empleando el Método de Bayes, herramienta novedosa en el campo de la investigación psicológica. La investigación se llevó a cabo en 66 sujetos mayores de 65 años, y los instrumentos utilizados para recabar información fueron la Prueba de Vocabulario de la Escala de lnteligencia de Wechsler para Adultos- lll, la Escala de Depresión Geriátrica de Yesavage, el Cuestionario de Afrontamiento de Estrés, las Escalas de Bienestar Psicológico de Ryff, el Mini Examen Cognoscitivo y el fndice de Barthel. Los resultados reflejan que, para nuestra muestra, no existiría relación entre la sintomatología depresiva y las variables de género, edad, estado civil e independencia física. Por el contrario, la ausencia de síntomas depresivos muestra una relación directa y positiva tanto con la variable deterioro cognitivo como el estilo de afrontamiento positivo (centrado en la focalización de problemas). Finalmente, el bienestar psicológico parece estar fuertemente ligado a la ausencia de sintomatología depresiva