Singular continuous spectrum is generic

In a variety of contexts, we prove that singular continuous spectrum is generic in the sense that for certain natural complete metric spaces of operators, those with singular spectrum are a dense $G_\delta$.Comment: 5 page

Nootropics use in the workplace. Psychiatric and ethical aftermath towards the new frontier of bioengineering

OBJECTIVE: The authors have sought to expound upon and shed a light on the rise of nootropics, which have gradually taken on a more and more relevant role in workplaces and academic settings. MATERIALS AND METHODS: Multidisciplinary databases have been delved into by entering the following keys: "nootropics", "cognitive enhancement", "workplace", "productivity", "ethics", "bioengineering". In addition, a broad-ranging search has been undertaken on institutional websites in order to identify relevant analysis and recommendations issued by international institutions and agencies. Papers and reports have been independently pored over by each author. This search strategy has led to the identification of 988 sources but only 64 were considered appropriate for the purposes of the paper after being selected by at least 3 of the authors, independently. RESULTS: The notion of an artificially enhanced work performance - carried out by the 'superworker' - is particularly noteworthy and resonates with the conception of contemporary work on so many different levels: the rising need and demands for higher degrees of flexibility and productivity on the job, the implications of a '24/7' society, where more and more services are available at any time, the ever greater emphasis on entrepreneurial spirit, individual self-reliance and self-improvement, and last but not least, the impact of an ageing society on economic standards and performance. CONCLUSIONS: Moreover, it is worth mentioning that human enhancement technologies will predictably and increasingly go hand in hand with gene editing, bioengineering, cybernetics and nanotechnology. Applications are virtually boundless, and may ultimately affect all human traits (physical strength, endurance, vision, intelligence and even personality and mood)

Exploring Challenging Properties of Liquid Metallic Systems through Machine Learning: Liquid La and Li4Pb Systems

In this machine learning (ML) study, we delved into the unique properties of liquid lanthanum and the Li4Pb alloy, revealing some unexpected features and also firmly establishing some of the debated characteristics. Leveraging interatomic potentials derived from ab initio calculations, our investigation achieved a level of precision comparable to first-principles methods while at the same time entering the hydrodynamic regime. We compared the structure factors and pair distribution functions to experimental data and unearthed distinctive collective excitations with intriguing features. Liquid lanthanum unveiled two transverse collective excitation branches, each closely tied to specific peaks in the velocity autocorrelation function spectrum. Furthermore, the analysis of the generalized specific heat ratio in the hydrodynamic regime investigated with the ML molecular dynamics simulations uncovered a peculiar behavior, impossible to discern with only ab initio simulations. Liquid Li4Pb, on the other hand, challenged existing claims by showcasing a rich array of branches in its longitudinal dispersion relation, including a high-frequency LiLi mode with a nonhydrodynamic optical character that maintains a finite value as q → 0. Additionally, we conducted an in-depth analysis of various transport coefficients, expanding our understanding of these liquid metallic systems. In summary, our ML approach yielded precise results, offering new and captivating insights into the structural and dynamic aspects of these materials.Ministerio de Economía y Competitividad, financiado parcialmente con fondos FEDER (proyecto PGC2018-093745-B-I00)Ministerio de Universidades y Universidad de Valladolid financiado parcialmente con fondos NextGenerationEU (programa María Zambrano

Redes sociais nas organizações

As redes sociais desempenham um papel fundamental nas organizações relacionadas à comunicação. Infelizmente, a literatura atual tem se concentrado apenas no uso de redes sociais dentro das comunidades para criação e interação entre a organização e os consumidores, principalmente em marketing digital e branding. Grande parte dessa literatura se enquadra em duas perspectivas interessantes, a importância da comunicação nas organizações e o uso das redes sociais como um novo canal de comunicação. As organizações precisam de comunicação como parte do entendimento entre a gerência e os funcionários, enquanto as redes sociais integram agentes às comunidades digitais. Este estudo resume a literatura sobre cada uma dessas perspectivas para derivar pressupostos e resultados esperados na comunicação com redes sociais dentro das organizações. Em seguida, por meio de uma perspectiva sociológica, propõe-se a conciliação dessas visões considerando a incorporação das redes sociais como uma nova forma de comunicação interna para as organizações. Há necessidade de integração de comunidades com redes sociais, com base no contexto de premissas feitas por estudos anteriores.Social networks play a key role in communication-related organizations. Unfortunately, the current literature has only been focused on the use of social networks within communities for creation and interaction between the organization and consumers, concerning mostly digital marketing and branding. Much of this literature falls under two interesting perspectives, the importance of communication in organizations and the use of social networks as a new communication channel. Organizations need communication as part of the understanding between management and employees, whereas social networks integrate agents into digital communities. This study summarizes the literature concerning each of these perspectives to derive assumptions and expected results on communication with social networks within organizations. Then, by means of a sociological perspective, the reconciliation of these views considering the incorporation of social networks as a new form of internal communication for organizations is proposed. There is a need for integration of communities with social networks, based on the context of premises made by previous studies.Las redes sociales desempeñan un papel clave en las organizaciones relacionadas con la comunicación. Desafortunadamente, la literatura actual solo se ha centrado en el uso de las redes sociales dentro de las comunidades para la creación e interacción entre la organización y los consumidores, en lo que concierne principalmente al marketing y el branding. Gran parte de esta literatura se inscribe en dos perspectivas interesantes, la importancia de la comunicación en las organizaciones y el uso de las redes sociales como un nuevo canal de comunicación. Las organizaciones necesitan la comunicación como parte del entendimiento entre la gerencia y los empleados, mientras que las redes sociales integran a los agentes en las comunidades digitales. Este estudio resume la literatura sobre cada una de estas perspectivas para derivar suposiciones y resultados esperados en la comunicación con redes sociales dentro de las organizaciones. Luego, a través de una perspectiva sociológica, se propone la conciliación de estos puntos de vista considerando la incorporación de las redes sociales como una nueva forma de comunicación interna para las organizaciones. Existe la necesidad de integración de las comunidades con las redes sociales, en función del contexto de las premisas realizadas por estudios anteriores

Ecuaciones para la estimación de biomasa de frondosas en España

To estimate forest carbon pools from forest inventories it is necessary to have biomass models or biomass expansion factors. In this study, tree biomass models were developed for the main hardwood forest species in Spain: Alnus glutinosa, Castanea sativa, Ceratonia siliqua, Eucalyptus globulus, Fagus sylvatica, Fraxinus angustifolia, Olea europaea var. sylvestris, Populus x euramericana, Quercus canariensis, Quercus faginea, Quercus ilex, Quercus pyrenaica and Quercus suber. Different tree biomass components were considered: stem with bark, branches of different sizes, above and belowground biomass. For each species, a system of equations was fitted using seemingly unrelated regression, fulfilling the additivity property between biomass components. Diameter and total height were explored as independent variables. All models included tree diameter whereas for the majority of species, total height was only considered in the stem biomass models and in some of the branch models. The comparison of the new biomass models with previous models fitted separately for each tree component indicated an improvement in the accuracy of the models. A mean reduction of 20% in the root mean square error and a mean increase in the model efficiency of 7% in comparison with recently published models. So, the fitted models allow estimating more accurately the biomass stock in hardwood species from the Spanish National Forest Inventory data.Para realizar estimaciones de cantidades de carbono acumulado por los bosques, a partir de datos procedentes de inventarios forestales, es necesario disponer de modelos de estimación de biomasa o de factores de expansión. En este trabajo se han ajustado modelos de estimación de biomasa para las principales especies forestales de frondosas existentes en los bosques españoles: Alnus glutinosa, Castanea sativa, Ceratonia siliqua, Eucalyptus globulus, Fagus sylvatica, Fraxinus angustifolia, Olea europea var. sylvestris, Populus x euramericana, Quercus canariensis, Quercus faginea, Quercus ilex, Quercus pyrenaica y Quercus suber. Se han determinado las siguientes fracciones: fuste con corteza, ramas de diferentes tamaños, parte aérea y parte radical. Para cada especie se ajustó un sistema de ecuaciones utilizando la metodología de mínimos cuadrados generalizados conjuntos, que contempla el cumplimiento de la propiedad aditiva entre fracciones. Como variables independientes se utilizaron el diámetro y la altura total del árbol. El diámetro aparece en todos los modelos, no así la altura, si bien su inclusión resulta en una mejora de las estimaciones en los modelos de biomasa de fuste para la mayoría de las especies y en parte de los modelos de ramas. La comparación con otros modelos desarrollados anteriormente para estas especies y ajustados con otra metodología, indica una mejora en la precisión de los aquí presentados. Existe una mejora media del 20% en términos de la raíz del error medio cuadrático y del 7% en la eficiencia del modelo. Así, mediante el uso de estos modelos ajustados se puede estimar con mayor precisión la biomasa y el carbono acumulado por estas especies de frondosas a partir de datos del Inventario Forestal Nacional de España

Covid-19: when health care resources run short, how to pick who should (not) get treated?

: The World Health Organization had long warned of the onset of a pandemic that could throw national health systems into a major crisis, even in wealthy developed nations. Nonetheless, almost a year and a half after its appearance, Covid-19 continues to make painful triage choices necessary in granting access intensive care. Based on the opinions of numerous ethics committees and scientific societies, the article aims to illustrate the difference between the utilitarian-collectivist approach and the ethical approach, which inspired the guidelines drawn up in Italy in 2021 by SIAARTI in collaboration with SIMLA. Only medical parameters should be evaluated to establish the prognosis through which to identify the patients to be treated as a priority. Otherwise, the patient's interest is subordinated to that of the community. But moral judgment cannot concern only the choices of doctors. According to the principle of beneficence, hospital directors and national and local health policy managers must also take action, in particular to eliminate waste of economic resources so as to allocate more of them to health protection, especially in consideration of the predictability with which infection rates increase, and in light of the fact that immunization through vaccination is only temporary