Determination of p-toluenesulfonic acid in n-butyl-2-cyanoacrylate monomer by liquidliquid extraction and UV detection

A simple standard addition method was developedfor determination of the anionic inhibitor p-toluenesulfonicacid in n-butyl-2-cyanoacrylate monomer.Aqueous extraction (pH 10) of the monomer samplesdiluted in chloroform was performed, and the analytewas estimated by means of UV absorption in the rangeof 0.15 to 1.50 g/l. The method developed providesacceptable precision and linearity and is suitable foruse in the routine quality control analysis

Estudio palinológico del género Phyllis L. en Canarias

Se estudian desde el punto de vista palinológico, tanto al microscopio óptico como al electrónico de barrido l as dos especies del género Phyl l is L. (Rubiaceae), endémico de l a Región Macaronésica (Canarias y 1·1adeira ), ·apreciándose algunas diferencias entre ambos taxones : g ranos mayores y con exina más gruesa en P. nabla L. que en P. viscosa Webb ex Chris t .A palynological study of the 2 s pecies fo the genus Phyllis L. (Rubiaceae ) , endemic to the Macaronesian Region (f•ladeira and Canary Islands) , has been carried out utilizing both optical and scanning electron microscopes . The resul ts ha ve s hown P. nabla L. to possess l arger grains with a thicker exine in comparison te P. viscosa Webb ex Chris

A centennial catalogue of hydro-geomorphological events and their atmospheric forcing

The DISASTER database records 1969 unique hydro-geomorphologic cases (floods and landslides) that generated human damages in Portugal during a 150 year-period (1865–2015. The main purposes of this work are the following: to present a national disaster events catalogue; to analyse the atmospheric conditions and to discuss the role of rainfall as main driving force of the hydro-geomorphological disaster events. The main Circulation Weather Types (CWTs) and the presence of Atmospheric Rivers (ARs) of each day of the disaster events were classified using the 20CR dataset (1865–2014) and the NCEP/NCAR reanalysis (2015). These datasets were used to compute the daily cumulative precipitation and the long term climatological year accumulated precipitation 10th, 50th, 90th and 95th percentile spanning 1865–2015 and the accumulated rainfall conditions after and before each disaster event. In the central and northern Portugal Disaster events are mainly driven by southwest (SW), west (W), northwest (NW) and Cyclonic (C) Weather Types, whereas the CWTs with a southern and eastern component [east (E), southeast (SE) and south (S)] are the main drivers in the south part of the country. Cyclonic CWT is widely associated with convective systems that can generate flash floods and urban floods often responsible for fatalities and injured people. CWTs with a westerly component can be associated to prolonged wet periods that can induce flood events in the main rivers and landslides in the mountain areas. The methodology used to build this disaster event catalogue can be applicable to other study areas, namely the North Atlantic and the Mediterranean regions, where the flood and landslides extremes are related to the atmospheric circulation.info:eu-repo/semantics/publishedVersio

A simple approach to synthesize g-C3N4 with high visible light photoactivity for hydrogen production

Se-modified g-C3N4 was synthesized from sonicated aqueous suspensions of melamine cyanurate and SeO2. The different thermal condensation temperatures in the 500–650 °C range were found to influence the photophysical properties and hydrogen evolution rates. H2 evolution increased dramatically by two orders of magnitude when Pt co-catalyst (1 wt.%) was incorporated, reaching an HER of 75 µmol H2/h

Obtención empírica del límite frecuencial entre las bandas de baja y altra frecuencia en análisis de variabilidad del ritmo cardíaco: aplicación en ratas y humanos

Se propone un nuevo método para la determinación empírica de los límites entre las bandas de baja frecuencia y alta frecuencia del espectro de potencia de las series RR en los estudios de variabilidad del ritmo cardíaco. El método se ha aplicado a series RR obtenidas en humanos y ratas Sprague-Dawley. Para humanos el límite coincide con la recomendación de 0,15 Hz mientras que para ratas Sprague-Dawley la metodología empleada sugiere un límite de 0,75 Hz.Postprint (published version

Estudio palinológico del género Rhamnus L. en Canarias

En base a material herborizado en nueve poblac iones di fer e ntes se estudia desde el punto de vista pal inológico (mi croscopía ópt i ca y microscopía el ectrónica de barrido) l as tres especies del género Rhamnus L. presentes en Canarias (R. crenulata Ait . , R. glandulosa Ai t . y R. integrifol i a DC.). Los resultados obtenidos ponen de manifiesto que en estas especies bien diferenciadas tanto desde el punto de vista macromorfológi co como ecológico , el polen no presenta var iac iones mor fol ógi cas notables y s u valor como carácter taxonómico es re lati vo . Me di ante l a ut ilización de métodos estadí sticos , se pone de mani f iesto l a vari ab i lidad de los parámetros P y E no sólo en diferentes poblaciones de un mi smo taxon, sino incluso dentro de una mi sma poblaciónOn the basis herbarium material originating f rom nine dif f eren t populati ons , a palynological study (opt ical and scanning electron microscoPY) has be en undertaken of the three speci es of the genus Rhamnus L. presen t in the Canary Isla nds (R. crenulata Ait . , R- glandulosa Ait . and R. integrifolia DC .) The results obtained demonstrate that wh ile these species ''lhich are c learly differentiable both macromorpholog i c a l l y and ecologically there are no notable variations in pollen morphology and i t s val ue as a tax.onomic character i s secondary . By means of statistical methods , t he variabi lity of the P and E parameters has been demons trated , not only i n di fferent populations of the same taxon but also even withi n t he same popu l ation

Mesoscopic modelling of 2-CN-PPV/PPV polymer LED

Although optoelectronic devices made of polymers are very attractive ones (low cost, easy to make), problems related to charge transport, exciton quenching, among others, can be an obstacle for their performance. The use of heterojunctions made of two polymers can be a strategy for improving the efficiency of polymer light emitting diodes (PLEDs) at low bias. Here we present a theoretical study of the influence of bilayer structure in a PLED made of PPV and 2-CN-PPV, by adopting a mesoscopic approach. Our results show that the presence of the polymer/polymer interface improves charge injection and leads to a confinement of charges near it, which will increase the number recombination events in the middle of the device compared to the equivalent single-layer PLEDs.Fundação para a Ciência e a Tecnologia (FCT) Programa Operacional “Ciência , Tecnologia, Inovação” POCTI/CTM/41574/2001, CONC-REEQ/443/EEI/2001 e SFRH/BD/22143/200

Ultrasonic evidence of an uncorrelated cluster formation temperature in manganites with first-order magnetic transition at T_C

Ultrasonic attenuation and phase velocity measurements have been carried out in the ferromagnetic perovskites La_{2/3}Ca_{1/3}MnO_3 and La_{2/3}Sr_{1/3}MnO_3. Data show that the transition at the Curie temperature, T_C, changes from first- to second-order as Sr replaces Ca in the perovskite. The compound with first-order transition shows also another transition at a temperature T* > T_C. We interpret the temperature window T_C < T < T* as a region of coexistence of a phase separated regime of metallic and insulating regions, in the line of recent theoretical proposals.Comment: 4 pages, 2 figure

The Chub Mackerel (Scomber Colias) in the Atlantic Spanish Waters (ICES Divisions 8.c and 9.a): Biological, fishery and survey data

Atlantic chub mackerel (Scomber colias , Gmelin, 1978) is a middle-sized pelagic fish distributed in warm and temperate Northeast Atlantic waters. The bulk of the catches takes place in north western waters of Africa, but landing are significantly increased in the most recent years in the Iberian Peninsula, resulting a new target species for both Portuguese and Spanish purse seiner fleets which partially replaces the important drop of sardine landings in both countries. Given this increasing importance and the lack, for the time being, of any scientific assessment, nor management plan and in order to update the available biological and catch information on this specie in Spanish Atlantic waters, this paper working document compile, review and analyze the existing data of biology, fisheries, and surveys to further enhance knowledge on chub mackerel in Atlantic Iberian waters (ICES Subdivisions 9.a South & North and Division 8.c), specifically: (i) stock structure, (ii) spatial distribution (iii) growth and reproduction and (iv) fisheries exploitation. This analysis suggests an increasing trend in Atlantic waters (9a) in both spatial distribution and abundance, mainly due to the strength of the 2015 and 2016 cohorts. This area, besides, could be considered as a nursery area while the Cantabrian Sea (8c) is rather main spawning area. The increase of such availability is also discussed within the frame of the North East Atlantic warming