Phase Diagram of a Classical Fluid in a Quenched Random Potential

We consider the phase diagram of a classical fluid in the presence of a random pinning potential of arbitrary strength. Introducing replicas for averaging over the quenched disorder, we use the hypernetted chain approximation to calculate the correlations in the replicated liquid. The freezing transition of the liquid into a nearly crystalline state is studied using a density functional approach, and the liquid-to-glass transition is studied using a phenomenological replica symmetry breaking approach introduced by Mezard and Parisi. The first-order liquid-to-crystal transition is found to change to a continuous liquid-to-glass transition as the strength of the disorder is increased above a threshold value.Comment: 7 pages, 4 figures, to appear in EuroPhysics Letter

Amalgamated products and properly 3-realizable groups

In this paper, we show that the class of all properly 3-realizable groups is closed under amalgamated free products (and HNN-extensions) over finite groups. We recall that $G$ is said to be properly 3-realizable if there exists a compact 2-polyhedron $K$ with $\pi_1(K) \cong G$ and whose universal cover $\tilde{K}$ has the proper homotopy type of a 3-manifold (with boundary).Comment: J. Pure Appl. Alg., to appea

COVID-19: My Life, My Experience

Student generated description: “Diary entires documenting my experience with COVID-19 and how it affected my mental health

Treating Bipolar Disorder and Schizophrenia with Biomedical Protocol

Bipolar Disorder and schizophrenia afflict approximately 2% of the human population, more than 12,400,000 people. When family members, co-workers, and care-givers are factored in, more than 10% of the population is directly impacted by these medical conditions. Finding a way to reduce the severity of the symptoms or cure these diseases would positively impact a large number of people. This paper defines and differentiates between these two similar-but-different maladies, and explores both the traditional courses of treatment as well as the most current research with potential to help combat these diseases – especially genetic mapping with the use of neuroimaging. Because genetic mapping has been successfully used to treat cancers, applying this technique to neurological disorders is the next logical step to take

Conceptual Model for Serious Games Design: Case Study of Children with Attention Deficit Hyperactivity Disorder

The field of Serious Games (SGs) is relatively new; however, so far, these have focused more on assessing impacts on results rather than identifying the most appropriate implementation phases to obtain a successful SG. The present work proposes a conceptual model for the design of SGs, which is based on four stages: Analysis, Design, Development, and Evaluation, under the life cycle of the software. For the validation of the model, an SG called ATHYNOS was developed, which was applied in a case study comparing it with the traditional therapy. The results obtained allowed to demonstrate that the SGs is a complementary tool for the treatment of children diagnosed with Attention Deficit Hyperactivity Disorder (ADHD).     Keywords: ATHYNOS, conceptual model, serious games design, attention deficit disorde

MECHANISTIC STUDY OF A RUTHENIUM HYDRIDE COMPLEX OF TYPE [RuH(CO)(N-N)(PR3)2]+ AS CATALYST PRECURSOR FOR THE HYDROFORMYLATION REACTION OF 1-HEXENE

Indexación: Web of Science; Scopus; Scielo.The catalytic activity of systems of type [RuH(CO)(N-N)(PR3)(2)](+) was evaluated in the hydroformylation reaction of 1-hexene. The observed activity is explained through a reaction mechanism on the basis of the quantum theory. The mechanism included total energy calculations for each of the intermediaries of the elemental steps considered in the catalytic cycle. The deactivation of the catalyst precursors takes place via dissociation of the polypyridine ligand and the subsequent formation of thermodynamically stable species, such as RuH(CO)(3)(PPh3)(2) and RuH3(CO)(PPh3)(2), which interrupt the catalytic cycle. In addition, the theoretical study allows to explain the observed regioselectivity which is defined in two steps: (a) the hydride migration reaction with an anti-Markovnikov orientation to produce the alkyl-linear-complex (3.1a), which is more stable by 19.4 kJ/mol than the Markovnikov orientation (alkyl-branched-complex) (3.1b); (b) the carbon monoxide insertion step generates the carbonyl alkyl-linear specie (4.1a) which is more stable by 9.5 kJ/mol than the alternative species (4.1b), determining the preferred formation of heptanal in the hydroformylation of 1-hexene. Palabras clavehttp://ref.scielo.org/db4yc

Dynamics and Dislodgment from Pore Constrictions of a Trapped Nonwetting Droplet Stimulated by Seismic Waves

Seismic waves affect fluid flow and transport processes in porous media. Therefore, quantitative understanding of the role of seismic waves in subsurface hydrodynamics is important for the development of practical applications and prediction of natural phenomena. We present a theoretical fluid dynamics model to describe how low-frequency elastic waves mobilize isolated droplets trapped in pores by capillary resistance. The ability of the theoretical model to predict the critical mobilization amplitudes (Ac) and the displacement dynamics of the nonwetting droplet are validated against computational fluid dynamics (CFD) simulations. Our theory has the advantage of rapid calculation of Ac for various scenarios. Both theory and CFD simulations show that the Ac increases with increasing wave frequency. The theoretical and computational models agree well in the low-frequency range both in terms of predicting the displacement history of the droplet and its eventual dislodgment, but their results begin to diverge with increasing wave frequency since the Hagen-Poiseuille flow approximation in the model becomes invalid. Relative to a previous viscous seismic model, our model compares more favorably to experimental observations. The model is thus appropriate for predicting trapped nonwetting droplet dynamics in and dislodgement from pore constrictions by low-frequency elastic waves