Orbital-Free Density Functional Theory with Continuous Normalizing Flows

Orbital-free density functional theory (OF-DFT) provides an alternative approach for calculating the molecular electronic energy, relying solely on the electron density. In OF-DFT, both the ground-state density is optimized variationally to minimize the total energy functional while satisfying the normalization constraint. In this work, we introduce a novel approach by parameterizing the electronic density with a normalizing flow ansatz, which is also optimized by minimizing the total energy functional. Our model successfully replicates the electronic density for a diverse range of chemical systems, including a one-dimensional diatomic molecule, specifically Lithium hydride with varying interatomic distances, as well as comprehensive simulations of hydrogen and water molecules, all conducted in Cartesian space.Comment: 6 pages, 3 figure

Síntesis, caracterización y reactividad de Complejos de iridio y rutenio con ligantes Tridentados de tipo escopionato y pincer

En el presente trabajo doctoral, se reporta la síntesis, caracterización estructural y reactividad de complejos de iridio con ligantes quinona (1,4-benzoquinona, 2-Cl-1,4- benzoquinona, 2-Ph-1,4-benzoquinona y 2-tBu-1,4-benzoquinona), alquenos electrofílicos (anhídrido maleico y p-NO2-fenil-maleimida) y ligantes de tipo escorpionato (TpmMe2 y TpMe2), así como complejos de rutenio que incorporan ligantes de tipo pincer y aplicaciones en catálisis. En primera instancia, se presenta la síntesis de complejos neutros del tipo [κ2- TpmMe2Ir(2,3,5,6-η-2-R-1,4-benzoquinona)Cl] (R = H, a; Cl, b; Ph, c; tBu, d) 1a-d, a partir del complejo dimérico de iridio [Ir(μ-Cl)(coe)2]2 con la adición de la respectiva quinona y el ligante TpmMe2

The Proton Spin and the Wigner Rotation

It is shown that in both the gluonic and strange sea explanations of the Ellis-Jaffe sum rule violation discovered by the European Muon Collaboration (EMC), the spin of the proton, when viewed in in its rest reference frame, could by fully provided by quarks and antiquarks within a simple quark model picture, taken into account the relativistic effect from the Wigner rotation.Comment: 13 latex page

Dissipative dynamics of vortex lines in superfluid 4^{4}He

We propose a Hamiltonian model that describes the interaction between a vortex line in superfluid $^{4}$He and the gas of elementary excitations. An equation of irreversible motion for the density operator of the vortex, regarded as a macroscopic quantum particle with a finite mass, is derived in the frame of Generalized Master Equations. This enables us to cast the effect of the coupling as a drag force with one reactive and one dissipative component, in agreement with the assumption of the phenomenological theories of vortex mutual friction in the two fluid model.Comment: 16 pages, no figures, to be published in PR

A comparison of the peers method and traditional methodologies, and risk behaviors in studies of the prevalence of drug consumption in a population of female, chilean students

Este estudio investiga el consumo de drogas y los comportamientos de riesgo de alumnas entre los 8º y 12º cursos en dos comunidades de la ciudad de Santiago, Chile. Empleando dos métodos para investigar el consumo, y basándonos en los estudios de poblaciones universitarias, hipotetizamos que los autoinformes de las alumnas sobre su consumo de drogas legales tenderán a ser consistentes con el uso real de dichas drogas, mientras que su consumo de drogas ilícitas será susceptible y tenderán a infra-informar de ello cuando se evalúa a través de medidas tradicionales de autoinforme. Para comparar los dos métodos, se diseñó un estudio transversal que compararía el consumo informado, primero empleando el método de pares, y después por medio del autoinforme tradicional, en un grupo de 350 alumnas. Los resultados muestran que los informes de las chicas sobre su consumo de drogas legales convergen empleando los dos métodos, mientras que, como se ha sugerido, infra-informaban sobre su consumo de drogas ilegales cuando se empleaban metodologías tradicionales.The present study investigates drug consumption and risk behaviors among female students between 8th and 12th grade in two communities in the city of Santiago, Chile. Based on studies of university populations, we hypothesize that the students’ reports of their consumption of licit drugs will tend to be consistent with their actual use of said drugs using two methods to investigate consumption, while their consumption of illicit drugs will be susceptible, and will tend to be under reported when evaluated through traditional self-report measures. In order to compare the two methods, a cross-sectional study was designed that would compare reported drug consumption, first using the peers method, and then by means of traditional self-report in a group of 350 students. The results show that women’s reports of licit drug consumption converge using the two methods, while as earlier suggested, women’s illicit drug consumption was found to be under reported when traditional methodologies were used

Pyrophosphate-Dependent ATP Formation from Acetyl Coenzyme A in Syntrophus aciditrophicus, a New Twist on ATP Formation.

UnlabelledSyntrophus aciditrophicus is a model syntrophic bacterium that degrades key intermediates in anaerobic decomposition, such as benzoate, cyclohexane-1-carboxylate, and certain fatty acids, to acetate when grown with hydrogen-/formate-consuming microorganisms. ATP formation coupled to acetate production is the main source for energy conservation by S. aciditrophicus However, the absence of homologs for phosphate acetyltransferase and acetate kinase in the genome of S. aciditrophicus leaves it unclear as to how ATP is formed, as most fermentative bacteria rely on these two enzymes to synthesize ATP from acetyl coenzyme A (CoA) and phosphate. Here, we combine transcriptomic, proteomic, metabolite, and enzymatic approaches to show that S. aciditrophicus uses AMP-forming, acetyl-CoA synthetase (Acs1) for ATP synthesis from acetyl-CoA. acs1 mRNA and Acs1 were abundant in transcriptomes and proteomes, respectively, of S. aciditrophicus grown in pure culture and coculture. Cell extracts of S. aciditrophicus had low or undetectable acetate kinase and phosphate acetyltransferase activities but had high acetyl-CoA synthetase activity under all growth conditions tested. Both Acs1 purified from S. aciditrophicus and recombinantly produced Acs1 catalyzed ATP and acetate formation from acetyl-CoA, AMP, and pyrophosphate. High pyrophosphate levels and a high AMP-to-ATP ratio (5.9 ± 1.4) in S. aciditrophicus cells support the operation of Acs1 in the acetate-forming direction. Thus, S. aciditrophicus has a unique approach to conserve energy involving pyrophosphate, AMP, acetyl-CoA, and an AMP-forming, acetyl-CoA synthetase.ImportanceBacteria use two enzymes, phosphate acetyltransferase and acetate kinase, to make ATP from acetyl-CoA, while acetate-forming archaea use a single enzyme, an ADP-forming, acetyl-CoA synthetase, to synthesize ATP and acetate from acetyl-CoA. Syntrophus aciditrophicus apparently relies on a different approach to conserve energy during acetyl-CoA metabolism, as its genome does not have homologs to the genes for phosphate acetyltransferase and acetate kinase. Here, we show that S. aciditrophicus uses an alternative approach, an AMP-forming, acetyl-CoA synthetase, to make ATP from acetyl-CoA. AMP-forming, acetyl-CoA synthetases were previously thought to function only in the activation of acetate to acetyl-CoA

Performance evaluation of a hybrid vehicle and sensor network to prevent traffic accidents

In recent years, wireless networks have become a widespread communication technology as well as a research challenge. Many contributions have been made on ad hoc networks, such as wireless sensor networks (WSNs) and vehicular ad hoc networks (VANETs). Recently, the number of cars on our streets, roads, and highways has been increasing, giving rise to a great interest in vehicular communication technologies. This paper presents an hybrid sensor and vehicular network (HSVN) platform, as well as the description and evaluation of a communication protocol between VANETs and WSNs using a network simulator for its evaluation