Electromagnetic field at finite temperature: A first order approach

In this work we study the electromagnetic field at finite temperature via the massless DKP formalism. The constraint analysis is performed and the partition function for the theory is constructed and computed. When it is specialized to the spin 1 sector we obtain the well-known result for the thermodynamic equilibrium of the electromagnetic field.     

New compounds from hyptis. X-ray crystal and molecular structures of anamarine

The structure (including absolute stereochemistry) of anamarine, a new unsaturated lactone isolated from an unclassified $\text{Hyptis}$ species, has been established.     

Self-diffusion in a gas-fluidized bed of fine powder

We have investigated the self-diffusion in a stable gas-fluidized bed of fine powder. Two regimes have been observed: for gas velocities v(g) above the minimum fluidization velocity v(m) and below a critical gas velocity v(c) smaller than the minimum bubbling velocity v(b) the powder does not mix. Experimental measurements show the existence of yield stresses in this regime which are responsible for the static behavior of the bed. For v(g)>v(c) the yield stress vanishes; the bed behaves like a fluid and displays a diffusive dynamics. In this region we have found that the diffusion coefficient D increases with gas velocity until the bed expansion approaches its maximum value.     

Looking for self-organized critical behavior in avalanches of slightly cohesive powders

We report results from a statistical analysis of avalanches of cohesive powders in a slowly rotated drum. Interparticle adhesion, which diminishes the effect of inertia and whose magnitude strongly fluctuates in a local scale, makes avalanches in slightly cohesive powders eligible for displaying self-organized criticality. However, the results show that avalanche sizes, time interval between avalanches, and maximum stable angle do not follow a power-law distribution. Otherwise, these parameters scale with powder cohesiveness.     

Parallel discrete dynamical systems on independent local functions

In this paper, we extend the manner of defining the evolution update of discrete dynamical systems on Boolean functions, without limiting the local functions to being dependent restrictions of a global one. Then, we analyze the cases concerned with parallel dynamical systems with the OR$OR$, AND$AND$, NAND$NAND$ and NOR$NOR$ functions as independent local functions over undirected and also directed dependency graphs. This extension of the update method widely generalizes the traditional one where only a global Boolean function is considered for establishing the evolution operator of the system. Besides, our analysis allows us to show a richer dynamics in these new kinds of parallel dynamical systems.     

Population dynamics of a two‐stage species with recruitment

This work models and analyzes the qualitative dynamics of a two‐stage species with the factor of recruitment. It shows how the dynamics is determined by a basic threshold parameter . As a result, it is proved that if , then the extinction equilibrium point is globally asymptotically stable, assuring that the species would disappear under this condition. Numerical simulations, produced by varying the parameters obtained from empirical data, show different situations regarding the evolution of the population and allow us to validate the model. Copyright © 2012 John Wiley & Sons, Ltd.     

Quantum communication via controlled holes in the statistical distribution of excitations in a nanoresonator coupled to a Cooper pair box

We propose a scheme to transmit information via the statistical distribution of excitations of a nanomechanical resonator. It employs a controllable coupling between this system and a Cooper pair box. The success probability and the fidelity are calculated and compared with those obtained in an atom-field system in different regimes. Addtionaly, the scheme can also be applied to prepare low excited Fock states.     

New trifluoromethyl triazolopyrimidines as anti-Plasmodium falciparum agents

According to the World Health Organization, half of the World's population, approximately 3.3 billion people, is at risk for developing malaria. Nearly 700,000 deaths each year are associated with the disease. Control of the disease in humans still relies on chemotherapy. Drug resistance is a limiting factor, and the search for new drugs is important. We have designed and synthesized new 2-(trifluoromethyl)[1,2,4]triazolo[1,5-a]pyrimidine derivatives based on bioisosteric replacement of functional groups on the anti-malarial compounds mefloquine and amodiaquine. This approach enabled us to investigate the impact of: (i) ring bioisosteric replacement; (ii) a CF? group substituted at the 2-position of the [1,2,4]triazolo[1,5-a]pyrimidine scaffold and (iii) a range of amines as substituents at the 7-position of the of heterocyclic ring; on in vitro activity against Plasmodium falciparum. P. falciparum dihydroorotate dehydrogenase (PfDHODH) through strong hydrogen bonds. The presence of a trifluoromethyl group at the 2-position of the [1,2,4]triazolo[1,5-a]pyrimidine ring led to increased drug activity. Thirteen compounds were found to be active, with IC?? values ranging from 0.023 to 20 μM in the anti-HRP2 and hypoxanthine assays. The selectivity index (SI) of the most active derivatives 5, 8, 11 and 16 was found to vary from 1,003 to 18,478.