FuzzyStatProb: An R Package for the Estimation of Fuzzy Stationary Probabilities from a Sequence of Observations of an Unknown Markov Chain

Markov chains are well-established probabilistic models of a wide variety of real systems that evolve along time. Countless examples of applications of Markov chains that successfully capture the probabilistic nature of real problems include areas as diverse as biology, medicine, social science, and engineering. One interesting feature which characterizes certain kinds of Markov chains is their stationary distribution, which stands for the global fraction of time the system spends in each state. The computation of the stationary distribution requires precise knowledge of the transition probabilities. When the only information available is a sequence of observations drawn from the system, such probabilities have to be estimated. Here we review an existing method to estimate fuzzy transition probabilities from observations and, with them, obtain the fuzzy stationary distribution of the resulting fuzzy Markov chain. The method also works when the user directly provides fuzzy transition probabilities. We provide an implementation in the R environment that is the first available to the community and serves as a proof of concept. We demonstrate the usefulness of our proposal with computational experiments on a toy problem, namely a time-homogeneous Markov chain that guides the randomized movement of an autonomous robot that patrols a small area

Diffusion of Mn interstitials in (Ga,Mn)As epitaxial layers

Magnetic properties of thin (Ga,Mn)As layers improve during annealing by out-diffusion of interstitial Mn ions to a free surface. Out-diffused Mn atoms participate in the growth of a Mn-rich surface layer and a saturation of this layer causes an inhibition of the out-diffusion. We combine high-resolution x-ray diffraction with x-ray absorption spectroscopy and a numerical solution of the diffusion problem for the study of the out-diffusion of Mn interstitials during a sequence of annealing steps. Our data demonstrate that the out-diffusion of the interstitials is substantially affected by the internal electric field caused by an inhomogeneous distribution of charges in the (Ga,Mn)As layer.Comment: 11 pages, 5 figure

Evidencia de citrato de sildenafilo en formulaciones herbolarias afrodisíacas comercializadas en San Salvador, El Salvador, por metodología HPLC-DAD y RMN 1H

Introduction: Herbal products have been used for the treatment of many diseases and unlike conventional drugs, they are perceived as safe and harmless due to their natural origin. The adulteration of natural products used for the improvement of sexual desire is becoming recurrent nowadays. Objective: This study detects the presence and determines the pharmacological dose of sildenafil citrate, a phosphodiesterase-5 inhibitor, in presumed adulterated natural products, that are commercialized in markets and “sex-shops” type store as stimulants of sexual desire in men. Methodology: The sildenafil content in 21 herbal products was identified and determined, using chromatographic and spectroscopic techniques (CCF, HPLC-DAD, and NMR 1H). Results: There was not evidence of the presence of sildenafil in the evaluated products from the markets. However, in the sex-shop type sales, with high probabilities of acquisition of adulterated products with this active principle, concentrations found were in a range from 12.7-132.2 mg/capsule. Representing lower, intermedium and higher doses than those recommended by the FDA. Conclusion: For consumers of fraudulent herbal products, there may be an interaction of sildenafil with vasodilator medicines such as nitrates, used for angina pectoris, and congestive heart failure. These interactions, together with the adverse cardiac-type (hypotensive) effects of sildenafil, could have serious effect on the health of consumers. Strict regulation of the natural products industry in sampled sites is urgedIntroducción: Los productos herbolarios han sido utilizados para el tratamiento de muchas enfermedades y a diferencia de los fármacos convencionales, se perciben seguros e inofensivos debido a su origen natural. La adulteración de productos naturales usados para la mejora del deseo sexual, se está volviendo recurrente en la actualidad. Objetivo: En este estudio se detecta la presencia y determina la dosis farmacológica de citrato de sildenafilo, un inhibidor de la fosfodiesterasa-5, en productos naturales, presuntamente adulterados, que se comercializan en mercados y tiendas tipo “sex-shop” como estimulantes del deseo sexual en hombres. Metodología: Se identifica y determina el contenido de sildenafilo en 21 productos herbolarios, a través de técnicas cromatográficas y espectroscópicas (CCF, HPLC-DAD y RMN 1H). Resultados: No existen evidencias de la presencia de sildenafilo en los productos evaluados procedentes de mercados, sin embargo, en las ventas tipo sex-shop, con altas probabilidades de adquisición de productos adulterados con este principio activo, se encontraron concentraciones que oscilan entre 12.7-132.2 mg/cápsula, dosis inferiores, próximas y superiores a las recomendadas por la FDA. Conclusión: Para los consumidores de productos herbolarios fraudulentos puede existir una interacción del sildenafilo con medicamentos vasodilatadores tipo nitratos, utilizados para la angina de pecho y la insuficiencia cardíaca congestiva. Estas interacciones aunado a los efectos adversos de tipo cardíaco (hipotensor) del sildenafilo en sí mismo, podría ser muy grave para la salud de los consumidores. Se insta a una estricta regulación de la industria de productos naturales en zonas muestreada

Potential use of pepper waste and microalgae Spirulina sp. for bioelectricity generation

The research aimed to generate bioelectricity using pepper waste and the microalgae Spirulina sp by a double-chamber microbial fuel cell (dcMFC). A dcMFC was constructed with Cu and Zn electrodes, where organic waste and microalgae were placed in the anodic and cathodic chambers, respectively. Also, electrochemical parameters were measured for 35 days. Finally, possible electrogenic microorganisms were isolated and identified. It was possible to generate maximum values of current (6.04414 ± 0.2145 mA) and voltage (0.77328 ± 0.213 V). The maximum conductivity value was 134.1636 ± 7.121 mS/cm, while the internal resistance value was 83.784 . The values of power and current density reached were 584.45 ± 19.14 mW/cm 2 and 5.983 A/cm 2, respectively. The optimal operating pH was 4.59 ± 0.14. From the microbial growth on the anode, the yeast Yarrowia phangngaensis (1) and Pseudomonas stutzeri (2) were identified, which may be involved in the transfer of electrons to the electrode. In conclusion, it was possible to generate clean energy in a laboratory-scale dcMFC when pepper waste and Spirulina sp. were used. These results are promising because organic waste can generate sustainable and environmentally friendly energy

Optimal Design of a Sustainable Hydrogen Supply Chain Network: Application in an Airport Ecosystem

Hydrogen and fuel cell technologies are one solution foraddressing the challenges that major airports are facing today, such asupward price trends of liquid hydrocarbon fuels, greenhouse gasemission regulations, and stricter noise and air pollutant emissionregulations, especially for on-ground pollution. An airport can also beviewed as the center of a hydrogen ecosystem, around which multiplehydrogen users could be clustered, with cost sharing of hydrogenproduction and storage occurring among users. The main novelty of thepresent work is the design of a hydrogen infrastructure irrigated by theairport ecosystem that satisfies the airport ecosystem energy needs. Forthis purpose, the model development is based on a multiobjectiveoptimization framework designed to consider four echelons: energysources, hydrogen production, transportation, and storage. Themultiperiod problem is then solved using theε-constraint method.Two objective functions are involved, that is, the total daily cost (TDC) of the network and an environmental indicator basedon the global warming potential. The second innovative contribution is to model the demand uncertainty using fuzzy conceptsfor a hydrogen supply chain design. Because hydrogen demand is one the most significant parameters, the uncertainty of thedemand has been considered using a proposed fuzzy linear programming strategy. The solutions are compared with the originalcrisp model, giving more robustness to the proposed approach. This work has been performed in the framework of the Hyportmeta-project and, in particular, within the“H2modeling”project. This paper focuses on a hydrogen airport ecosystem located inthe department of Hautes-Pyrénées (France). However, the developed methodology could be extended to other hydrogenecosystems for which deployment involves a multiperiod multi-objective formulation under an uncertain deman

Gangrena de Fournier en paciente obeso con COVID-19: reporte de caso

La Gangrena de Fournier (GF) es una fascitis necrotizante que afecta los planos superficiales. Se presenta frecuentemente en hombres entre 50 y 79 años con una elevada tasa de mortalidad, la cual aumenta con la presencia de factores de riesgo destacándose entre ellos la diabetes y obesidad. Se reporta el caso de un paciente obeso diagnosticado con COVID-19 antes del ingreso y tratado con corticoides, que acude por aparente celulitis escrotal que evoluciona a GF, la cual fue diagnosticada 2 días luego de la hospitalización. Se le realiza intervención quirúrgica inmediata, previa cobertura antibiótica. La COVID-19 no tuvo relevancia clínica en la evolución y pronóstico de la GF; sin embargo, fueron las terapias desmesuradas las que influyeron negativamente. A pesar de ello, el paciente evolucionó favorablemente hasta su recuperación total. Palabras clave: Gangrena de Fournier, obesidad, COVID-19 (MeSH) DOI: http://dx.doi.org/10.17268/rmt.2020.v16i01.1

Recording Earthen Architecture at the Peruvian Andes: the Case of KUÑO Tambo CHURCH'S Historic Wall Paintings

According to UNESCO “Earthen architecture is one of the most original and powerful expressions of our ability to create a built environment with readily available resources. It includes a great variety of structures, ranging from mosques, palaces and granaries, to historic city centres, cultural landscapes and archaeological sites” (WHEAP, 2007). This contribution looks at developing effective methods for recording earthen his

Cuantificación de sesquiterpenlactonas procedentes de las hojas de Calea urticifolia (Asteraceae) durante el año 2012

El presente estudio tuvo como objetivo principal la cuantificación de sesquiterpenlactonas presentes en los extractos cloro fórmicos secos de hojas de Calea urticifolia “Juanislama”, recolectadas bimensualmente durante el año 2012. Los metabolitos secundarios se extrajeron por medio del método Soxhlet usando cloroformo como solvente; se llevó a cabo la identificación de los metabolitos secundarios por cromatografía en capa fina con reactivo de Baljet y espectroscopía UV utilizando marcadores analíticos. La cuantificación se realizó por espectroscopía visible usando Juanislamina como marcador analítico, encontrándose que el porcentaje de sesquiterpenlactonas totales expresadas como Juanislamina en el extracto clorofórmico seco vario entre 39.58-90.02%, observándose el periodo del 02-02 al 15-04, 18-07 al 31-07 y 30-08 al 17-09 como los mejores, destacándose la recolecta del 15-02 con 90.02%; con respecto al porcentaje de sesquiterpenlactonas totales en el material vegetal seco, este vario entre 2.84-8.06%, observándose los periodos del 15-03 al 15-04 y 30-08 al 17-09 como los mejores, destacándose la recolecta del 30-03 con 8.06%.Quantification of sesquiterpene lactones present in dried leaves of Calea unticifolia “Juanislama” was systematically carried out for the whole year 2012. Leaves samples were recollected bimonthly, and the sesquiterpene lactones were extracted utilizing the Soxhlet method with chloroform as solvent. The identification of the secondary metabolites was performed by thin-layer chromatography using the Baljet reagent and by UV/Vis spectroscopy utilizing chemical markers. The concentration of total sesquiterpene lactones, expressed as Juanislamine, found in the dried chloroform extract ranged from 39.58 to 90.02%. It was observed that the time periods from February 2 to April 15, from July 18 to July 31, and from August 30 to September 17 displayed the best yields, being the sampling on February 15 the one that led to the highest yield at an outstanding 90.02%. Regarding the percentage of total sesquiterpene lactones in the dried vegetal material, this ranged from 2.84% to 8.06% in the study. Likewise, the best time periods for such percentage fell from March 15 to April 15, and from August 30 to September 17, distinguishing the sample taken on March 30, which yielded a maximum of 8.06% of sesquiterpene lactones in the dried material

Best practice guidelines for environmental DNA biomonitoring in Australia and New Zealand

Environmental DNA (eDNA)- based methods are increasingly used by government agencies to detect pests and threatened species, and for broader biodiversity monitor-ing. Given rapid technological advances and a growing number of commercial service providers, there is a need to standardize methods for quality assurance and to main-tain confidence in eDNA- based results. Here, we introduce two documents to pro-vide best- practice guidelines for Australian and New Zealand eDNA researchers and end- users (available from https://sedna socie ty.com/publications ): the Environmental DNA protocol development guide for biomonitoring provides minimum standard consid-erations for eDNA and environmental RNA projects across the complete workflow, from ethical considerations and experimental design to interpreting and communicat-ing results. The Environmental DNA test validation guidelines outline key steps to be used in assay development and validation for species-specific testing and metabar-coding. Both guidelines were developed as an initiative of the Australian Government Department of Agriculture, Fisheries and Forestry and led by the Southern eDNA Society in a collaborative process including multiple consultation rounds with eDNA experts, end-users, and stakeholders to adapt the guidelines to Australian and New Zealand needs. The aim of these guidelines is not to be prescriptive, but to set mini-mum standards to support a consistent and best- practice approach to eDNA testing. We anticipate that the guidelines will be reviewed and regularly updated as required. Our aspiration is that these best- practice guidelines will ensure environmental man-agers are provided with robust scientific evidence to support decision- making

High-accuracy determination of the neutron flux in the new experimental area n_TOF-EAR2 at CERN

A new high flux experimental area has recently become operational at the n_TOF facility at CERN. This new measuring station, n_TOF-EAR2, is placed at the end of a vertical beam line at a distance of approximately 20m from the spallation target. The characterization of the neutron beam, in terms of flux, spatial profile and resolution function, is of crucial importance for the feasibility study and data analysis of all measurements to be performed in the new area. In this paper, the measurement of the neutron flux, performed with different solid-state and gaseous detection systems, and using three neutron-converting reactions considered standard in different energy regions is reported. The results of the various measurements have been combined, yielding an evaluated neutron energy distribution in a wide energy range, from 2meV to 100MeV, with an accuracy ranging from 2%, at low energy, to 6% in the high-energy region. In addition, an absolute normalization of the n_TOF-EAR2 neutron flux has been obtained by means of an activation measurement performed with 197Au foils in the beam.Peer reviewe