Domain wall dynamics in an optical Kerr cavity

An anisotropic (dichroic) optical cavity containing a self-focusing Kerr medium is shown to display a bifurcation between static --Ising-- and moving --Bloch-- domain walls, the so-called nonequilibrium Ising-Bloch transition (NIB). Bloch walls can show regular or irregular temporal behaviour, in particular, bursting and spiking. These phenomena are interpreted in terms of the spatio-temporal dynamics of the extended patterns connected by the wall, which display complex dynamical behaviour as well. Domain wall interaction, including the formation of bound states is also addressed.Comment: 15 pages Tex file with 11 postscript figures. Resubmitted to Phys. Rev.

Diseño de un sistema de disipación de energía para un edifico en altura

Se considera en este trabajo un edificio sismorresistente aporticado de hormigón armado, de 21 niveles, diseñado para Guayaquil, Ecuador. El objetivo del estudio es desarrollar un procedimiento de diseño de un sistema de disipación pasiva de energía (barras de pandeo restringido) para mejorar los parámetros de respuesta de la estructura original. Se diseñan los disipadores según el procedimiento que se explicita, y luego se realiza un análisis dinámico de historia en el tiempo para la estructura con / sin disipadores, bajo la excitación de 5 acelerogramas. Los resultados del modelo numérico muestran la eficiencia del sistema de disipación propuesto.Postprint (published version

Liderazgo directivo y gestión administrativa en instituciones educativas de una red del distrito de Comas

Esta investigación que tuvo como objetivo general determinar la relación entre el liderazgo directivo y la gestión administrativa en instituciones educativas de una red del distrito de Comas; ha cumplido con cada uno de los procesos para poder encontrar respuesta a la problemática identificada. En el aspecto metodológico el estudio fue básico, de enfoque cuantitativo, diseño no experimental. Conformado por una población de 352 docentes que forman parte de 14 instituciones educativas pertenecientes a una red del distrito de Comas que corresponde a la Ugel 04 de Lima Metropolitana. Con una muestra no probabilística conformada por 116 profesores pertenecientes a 03 colegios de una red del distrito de Comas. Utilizó la técnica de la encuesta para recolectar información y se registró las respuestas en dos cuestionarios de 20 preguntas cada uno. Validado por juicio de expertos y sometido a prueba de confiabilidad de Alfa de Cronbach. La conclusión general indica que hay evidencias para poder determinar que existe relación directa entre el liderazgo directivo y la gestión administrativa en instituciones educativas de una red del distrito de Comas, 2019. Además, el valor del coeficiente de correlación Rho es = ,634 lo que indica una correlación positiva de nivel medio alto. La significancia p = ,000 < ,050

On the accumulation points of non-periodic orbits of a difference equation of fourth order

PreprintIn this paper, we are interested in analyzing the dynamics of the fourth-order difference equation x_{n+4}=max{x_{n+3},x_{n+2},x_{n+1},0}-x_n, with arbitrary real initial conditions. We fully determine the accumulation point sets of the non-periodic solutions that, in fact, are configured as proper compact intervals of the real line. This study complements the previous knowledge of the dynamics of the difference equation already achieved in [M. Csörnyei, M. Laczkovich, Monatsh. Math. 132 (2001), 215-236] and [A. Linero Bas, D. Nieves Roldán, J. Difference Equ. Appl. 27 (2021), no. 11, 1608-1645]This work has been supported by the grant MTM2017-84079-P funded by MCIN/AEI/10.13039/501100011033 and by ERDF “A way of making Europe”, by the European Union. The second autor acknowledges the group research recognition 2021 SGR 01039 from Agència de Gestió d’Ajuts Universitaris i de RecercaPreprin

Cyanate Assimilation by the Alkaliphilic Cyanide-Degrading Bacterium Pseudomonas pseudoalcaligenes CECT5344: Mutational Analysis of the cyn Gene Cluster

The alkaliphilic bacterium Pseudomonas pseudoalcaligenes CECT5344 can grow with cyanate, cyanide, or cyanide-containing industrial residues as the sole nitrogen source, but the assimilation of cyanide and cyanate takes place through independent pathways. Therefore, cyanide degradation involves a chemical reaction between cyanide and oxaloacetate to form a nitrile that is hydrolyzed to ammonium by the nitrilase NitC, whereas cyanate assimilation requires a cyanase that catalyzes cyanate decomposition to ammonium and carbon dioxide. The P. pseudoalcaligenes CECT5344 cynFABDS gene cluster codes for the putative transcriptional regulator CynF, the ABC-type cyanate transporter CynABD, and the cyanase CynS. In this study, transcriptional analysis revealed that the structural cynABDS genes constitute a single transcriptional unit, which was induced by cyanate and repressed by ammonium. Mutational characterization of the cyn genes indicated that CynF was essential for cynABDS gene expression and that nitrate/nitrite transporters may be involved in cyanate uptake, in addition to the CynABD transport system. Biodegradation of hazardous jewelry wastewater containing high amounts of cyanide and metals was achieved in a batch reactor operating at an alkaline pH after chemical treatment with hydrogen peroxide to oxidize cyanide to cyanate

Assessment of Characteristics and Conditions before the End of Lockdown

After months of blockades and restriction, the decision of the best time to end the lockdown after the first wave of the COVID-19 pandemic is the big question for health rectors. This study aimed to evaluate the characteristics and conditions for ending the blockade after the first wave of COVID-19. Data on the variables of interest were subjected to linear and non-linear regression studies to determine the curve that best explains the data. The coefficient of determination, the standard deviation of y in x, and the observed curve of the confidence interval were estimated. Regression which was estimated subsequently revealed the trend curve. The study found that all dependent variables tend to decrease over time in a quadratic fashion, except for the variable for new cases. In general, the R2 and mean absolute percentage error (MAPE) estimates were satisfactory: gradual and cautious steps should be taken before ending the lockdown. The results suggested that a surveillance of crucial indicators (e.g., incidence, prevalence, and PCR test positivity) should be maintained before lockdown is terminated. Moreover, the findings indicated that long-term preparations should be made to contain future waves of new cases

Influence of Different Vinification Techniques on Volatile Compounds and the Aromatic Profile of Palomino Fino Wines

The aim of this study was to evaluate the influence of vinification techniques on volatile compounds and sensory profiles in young Palomino fino white wines. Four winemaking techniques (pellicular maceration, supra-extraction and use of commercial yeast strains and of beta-glycosidase enzymes) were implemented to enhance the aromatic quality of wines elaborated from this neutral variety of grape. Volatile compound content, aromatic profile (OAVs) and sensorial analysis were determined. The results showed that all the vinification techniques studied led to an increase in volatile compounds compared to the control wine. Likewise, an influence of the vineyard and must extraction method on these compounds was observed. However, the greatest changes in aroma activity and sensory profile were a result of the pellicular maceration and supra-extraction techniques. The latter was differentiated by the highest content of terpenes and, consequently, the highest odour activity values of floral series. In addition, the supra-extraction was a very selective technique since it extracted terpenes and aromatic precursors, but not the acids responsible for the fatty characteristic, such as octanoic acid. In terms of sensory profile, the supra-extraction technique improved the intensity of the Palomino fino white wine and its aromatic quality with a previously not-determined floral character

Physicochemical and microbiological characterization of the sensory deviation responsible for the origin of the special sherry wines "palo cortado" type

The aim of this study was to characterize the biochemical changes and microbiological processes involved in the sensory deviation of “sobretablas” wines during biological aging, which leads to the origin of special or rare “palo cortado” wines. Industrial trials of biological aging of “sobretablas” wines with the potential for the development of lactic acid bacteria (LAB) were performed to study this phenomenon. The results showed that sensory deviation was due to the development of malolactic fermentation (MLF) together with an attenuated aerobic metabolism of “flor” yeast. Malolactic fermentation (MLF) was promoted by the presence of malic acid concentrations that were higher than 1 g/L and the coexistence of LAB and “flor” velum yeast. Ethyl lactate, acetoin and 2,3-butanediol are some of the volatile compounds that are responsible for this sensory deviation. Wines with high levels of gluconic and malic acids (> 1 g/L) can cause, with very low probability, the sensory deviation of “palo cortado”. A lysozyme dose of 12 g/hL is an effective treatment to avoid malolactic fermentation (MFL) and sensory deviation. Understanding the biochemical and microbiological changes involved in sensory deviation can be useful to wineries as markers to identify the origin of the special sherry wines "palo cortado" type

Cavity solitons in bidirectional lasers

We show theoretically that a broad area bidirectional laser with slightly different cavity losses for the two counterpropagating fields sustains cavity solitons (CSs). These structures are complementary, i.e., there is a bright (dark) CS in the field with more (less) losses. Interestingly, the CSs can be written/erased by injecting suitable pulses in any of the two counterpropagating fields.Comment: 4 figure

Polymorphic transformation from body-centered to face-centered cubic vanadium metal during mechanosynthesis of nanostructured vanadium nitride determined by extended x-ray absorption fine structure spectroscopy

The pathway for vanadium nitride VN formation obtained by milling treatment has been traced out. At the initial stages of the process, the reactant, vanadium metal, showing body-centered cubic bcc structure, becomes highly distorted. Simultaneously, the formation of a small nucleus of the product, VN, takes place. X-ray absorption spectroscopy XAS has allowed the quantification of the distortion degree as well as the detection of the VN nucleus in the early stages of their formation, while other standard structural characterization techniques are unable to detect such phenomena. For increasing milling times, apart from the expected increase in the size of the VN nucleus, a polymorphic transformation from bcc to fcc vanadium metal has been recorded. This phase might play a key role in the overall synthesis process and could be a reaction intermediate in other solid state processes involving V metal. The sensitivity of XAS to noncrystalline domains and to highly distorted environments, as well as the use of high resolution x-ray diffraction, has provided the relevant information to understand the whole reaction process.European Synchrotron Radiation Facility (ESRF)-ME-737SpLine CRG (beamline BM25 at the ESRF)-25- 01-657Ministerio de Educación y Ciencias de España-BQU2002-04364-C02-01 y BQU2002- 04364-C02-