Synchronization of the Frenet-Serret linear system with a chaotic nonlinear system by feedback of states

A synchronization procedure of the generalized type in the sense of Rulkov et al [Phys. Rev. E 51, 980 (1995)] is used to impose a nonlinear Malasoma chaotic motion on the Frenet-Serret system of vectors in the differential geometry of space curves. This could have applications to the mesoscopic motion of biological filamentsComment: 12 pages, 7 figures, accepted at Int. J. Theor. Phy

Synthesis and Characterization of CoMo/Al2O3-MgO-(X) catalysts doped with alkaline oxides (K, Li)

CoMo catalysts were prepared using Al2O3-MgO-(X) hybrid supports, where X = K2O or Li2O. The textural, structural and acid-base properties of these materials were characterized by several techniques. The catalysts were preliminarily evaluated in the hydrodesulfurization (HDS), hydrogenation (HYD) and hydrocracking (HCK) model reactions. The aims of this work are to identify the effect of the addition of an alkaline oxide (either K2O or Li2O) to the Lewis acid sites in the CoMo/Al2O3-MgO formulation; and on the other hand, to establish a relationship between the acidity and the catalytic performance (hydrogenation function). The results obtained from the pyridine thermodesorption analysis and the n-butyl amine titration techniques show that the incorporation of an alkaline oxide to the CoMo/Al2O3-MgO formulation causes a slight decrease in the total number of acid sites (TNAS) with respect to Al2O3 and the Al2O3-MgO hybrid supports. Both the enhanced textural and structural stability of the CoMo/Al2O3-MgO-(X) catalytic formulations, which could be probably attributed to the incorporation of Li or K cations to the MgO framework, stabilizing it, can also be observed. As for the catalytic performance, the CoMo/Al2O3-MgO-(X) catalysts containing either Li2O or K2O, show a decrease in both the HYD and HYC conversions; however, the formulation containing Li2O shows the best catalytic behavior due to both the low n-octane yield and the low hydrocracking activity

On the Gannon-Lee Singularity Theorem in Higher Dimensions

The Gannon-Lee singularity theorems give well-known restrictions on the spatial topology of singularity-free (i.e., nonspacelike geodesically complete), globally hyperbolic spacetimes. In this paper, we revisit these classic results in the light of recent developments, especially the failure in higher dimensions of a celebrated theorem by Hawking on the topology of black hole horizons. The global hyperbolicity requirement is weakened, and we expand the scope of the main results to allow for the richer variety of spatial topologies which are likely to occur in higher-dimensional spacetimes.Comment: 13 pages, no figures, to appear in Class. Quantum Gra

Haptic guidance improves the visuo-manual tracking of trajectories

BACKGROUND: Learning to perform new movements is usually achieved by following visual demonstrations. Haptic guidance by a force feedback device is a recent and original technology which provides additional proprioceptive cues during visuo-motor learning tasks. The effects of two types of haptic guidances-control in position (HGP) or in force (HGF)-on visuo-manual tracking ("following") of trajectories are still under debate. METHODOLOGY/PRINCIPALS FINDINGS: Three training techniques of haptic guidance (HGP, HGF or control condition, NHG, without haptic guidance) were evaluated in two experiments. Movements produced by adults were assessed in terms of shapes (dynamic time warping) and kinematics criteria (number of velocity peaks and mean velocity) before and after the training sessions. CONCLUSION/SIGNIFICANCE: These results show that the addition of haptic information, probably encoded in force coordinates, play a crucial role on the visuo-manual tracking of new trajectories

New laccase-producing fungi isolates with biotechnological potential in dye decolorization

Thirty six (36) native fungal strains from the state of Yucatan were first screened for ligninolytic activity on solid media containing ABTS. Molecular identification based on ITS rDNA region and PCR fingerprinting of seven selected fungi isolates were carried out. Molecular characterization based on genetic fingerprinting was helpful in determining unequivocally the differences between isolates at genera and species levels. The seven isolates showed ABTS oxidation zones in plates but only five strains produced extracellular laccase. The strains identified as Trametes hirsuta (GenBank accession numbers GQ280372 and GQ280373) showed the highest laccase production. The strain Bm-2 displayed the greatest laccase activity and dye decolourization ability in 72 h without the addition of mediators. Both the high laccase activity shown by Bm-2 and its ability to decolorize dyes are a good indication of its possible use in the treatment of textile effluents.Key words: Laccase, Trametes hirsuta, dye decolorization, PCR fingerprinting

Age-related decline of de novo T cell responsiveness as a cause of COVID-19 severity

To the Editor, So far, little attention has been paid to the link between immunosenescence and the dramatic mortality rate of coronavirus disease 2019 (COVID-19) in older age groups. Indeed, the number of cases of COVID-19, caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), is very low among children and teenagers, in contrast to the increased frequency in adults and the elderly, who are also more at risk of developing very serious symptoms and death (Guan et al. 2020; Wu and McGoogan 2020). As shown in Fig. 1, a similar epidemiological profile was observed during previous coronavirus (severe acute respiratory syndrome coronavirus 1, SARS-CoV-1, and Middle east respiratory syndrome coronavirus, MERS-CoV) outbreaks (Jia et al. 2009; Salamatbakhsh et al. 2019). Notably, the same trend was also noted during West Nile virus and, with some exceptions in very young children, Ebolavirus outbreaks (Bower et al. 2016; Hayes et al. 2005). Likely this phenomenon is multifactorial. For instance, in elderly individuals with severe COVID-19, associated comorbidities are much more prevalent (Guan et al. 2020). In addition, the progressive accumulation of senescent cells during life may play a role in the vulnerability of old people to COVID-19, resulting in reduced functionality of the organs, such as the lungs, and facilitating conditions for the development of fibrosis. Moreover, senescent cells can generate a pro-inflammatory environment, referred to as SASP (for senescence-associated secretory phenotype), which includes many inflammatory cytokines (e.g., interleukin-6) and contributes to the basal hyperinflammatory status characteristic of the old person. This hyperinflammatory status might influence the expression of ACE2, CD147, cyclophilins, CD26, and other CoV-associated molecules in human tissues, thus favoring viral entry (Radzikowska et al. 2020). It likely also constitutes an already unbalanced pro-inflammatory background, on which the development of an exacerbated inflammatory response and acute respiratory distress syndrome may be facilitated upon SARS-CoV-2 infection

Polyelectrolyte Multilayering on a Charged Planar Surface

The adsorption of highly \textit{oppositely} charged flexible polyelectrolytes (PEs) on a charged planar substrate is investigated by means of Monte Carlo (MC) simulations. We study in detail the equilibrium structure of the first few PE layers. The influence of the chain length and of a (extra) non-electrostatic short range attraction between the polycations and the negatively charged substrate is considered. We show that the stability as well as the microstructure of the PE layers are especially sensitive to the strength of this latter interaction. Qualitative agreement is reached with some recent experiments.Comment: 28 pages; 11 (main) Figs - Revtex4 - Higher resolution Figs can be obtained upon request. To appear in Macromolecule

Description of the Immatures of Workers of the Ant Linepithema micans Forel (Hymenoptera: Formicidae).

Linepithema micans Forel is a poorly studied species that is now considered a pest in vineyards in South Brazil. Larval characters have been used in a few phylogenetic studies, and their importance greatly depends in the amount of available information on different species. This study presents a complete panorama on the external morphology of the immatures of L. micans based on observations by light and scanning electron microscopy. The number of larval instars was estimated as three based on the frequency distribution of head widths of 965 larvae. Larvae of L. micans were similar to other Linepithema Mayr in the general format of body and mandibles, presenting a dorsal abdominal protuberance, nine pairs of spiracle, and unbranched hairs. On the other hand, L. micans was unique for having shorter hairs, predominantly denticulate, intraspecific variation in the number of antennal sensilla and in the types of sensilla on the labial palps were reported

Collective Decision Dynamics in the Presence of External Drivers

We develop a sequence of models describing information transmission and decision dynamics for a network of individual agents subject to multiple sources of influence. Our general framework is set in the context of an impending natural disaster, where individuals, represented by nodes on the network, must decide whether or not to evacuate. Sources of influence include a one-to-many externally driven global broadcast as well as pairwise interactions, across links in the network, in which agents transmit either continuous opinions or binary actions. We consider both uniform and variable threshold rules on the individual opinion as baseline models for decision-making. Our results indicate that 1) social networks lead to clustering and cohesive action among individuals, 2) binary information introduces high temporal variability and stagnation, and 3) information transmission over the network can either facilitate or hinder action adoption, depending on the influence of the global broadcast relative to the social network. Our framework highlights the essential role of local interactions between agents in predicting collective behavior of the population as a whole.Comment: 14 pages, 7 figure