Els territoris del negoci elèctric. El model de Pearson i la seva aplicació a Sao Paulo, México D.F., Rio de Janeiro i Barcelona

L’etapa d’introducció de l’electricitat a les ciutats, entre finals del segle XIX i principis del segle XX, està directament relacionada al sorgiment d’una nova tecnologia i als seus primers avenços, així com a una sèrie d’enginyers i capitalistes que van veure tant les possibilitats de desenvolupament que oferia com el gran negoci que s’hi amagava darrera. Frederick Stark Pearson (1861-1915), va ser un dels actors clau en aquesta etapa, un enginyer estadunidenc que dominava els coneixements tècnics relacionats amb l’última tecnologia elèctrica i les altes finances, i els combinavava a la perfecció. Aquests coneixements i l’absoluta confiança en el progrés que aportava l’electricitat el van portar a fundar grans monopolis elèctrics basats en la hidroelectricitat per tot el continent americà i finalment a Barcelona, recolzat pels principals capitalistes del Canadà. La literatura al respecte de les empreses que va promoure és força extensa (només de les que avui en dia encara estan en servei), però bàsicament tracta els aspectes econòmics o socials que s’en van derivar. La visió espacial i restística no està estudiada, ni s’ha fet un resseguiment de la seva trajectoria, bàsic per entendre com va actuar en cada cas

Translation numbers in a Garside group are rational with uniformly bounded denominators

It is known that Garside groups are strongly translation discrete. In this paper, we show that the translation numbers in a Garside group are rational with uniformly bounded denominators and can be computed in finite time. As an application, we give solutions to some group-theoretic problems.Comment: 12 pages, to appear in J. Pure Appl. Algebr

Authentication of paprika using HPLC-UV fingerprints

In this work we combine simple extraction and HPLC-UV methodologies with chemometric pattern-recognition strategies in order to obtain characteristic fingerprints of phenolic compounds that allow the authentication of paprika samples. To illustrate the potential of the proposed approach, two different adulteration scenarios were considered, namely adulteration of paprika based on its type (sweet, bittersweet and spicy) as well as on its region (Murcia, la Vera and Czech Republic). Upon preparation of a proper set of samples, those were analysed using a C18 reversed-phase column and registered chromatograms were then compressed employing fast Fourier transform (FFT) to reduce the large dimensionality of the data set, while preserving all relevant features. Next, data were analysed using linear discriminant analysis (LDA) for the qualitative discrimination of adulterated samples, or by partial least-squares regression (PLS) modelling to quantitatively assess the adulteration degree

Types d'orbites et dynamique minimale pour les applicationes continues de graphes

We define the type of a periodic orbit of a graph map. We consider the class of ‘train-track’ representatives, that is, those graph maps which minimize the topological entropy of the topological representatives of a given free group endomorphism. We prove that each type of periodic orbit realized by an efficient representative is also realised by any representative of the same free group endomorphism. Moreover, the number of periodic orbits of a given type is minimized by the efficient representatives

Infraestructuras al servicio de la estrategia territorial

Habitualmente encontramos estudios justificativos que presuponen crecimientos tendenciales ilimitados del tráfico de vehículos. Los modelos utilizados, con una base científica incorporan la mayor parte de los factores que influyen en el tráfico, dándoles una aparente objetividad incuestionable. Pero raramente se obtienen evoluciones negativas, aún siendo este uno de los principales retos, y es que todavía están basadas en las políticas del progreso inducido por las infraestructuras del transporte, con lo que en su génesis deben justificar cualquier tipo de infraestructura. Forman parte de los denominados enfoques de demanda que van al margen de la estrategia territorial. En el presente artículo se presenta una nueva metodología en la prognosis de movilidad intermunicipal al servicio de la planificación territorial y basada en los enfoques de oferta, vinculada a una nueva política de infraestructuras. La principal motivación es fijar la movilidad intermunicipal deseada y su reparto modal en base a las directrices territoriales; en vez de adaptar la oferta de infraestructuras a una demanda estimada, adaptar la demanda a una oferta en infraestructuras flexible en el tiempo, lo que supone cambiar el orden metodológico en la planificación de infraestructuras de transporte, reconociendo el estrecho vínculo entre modelo territorial y política de transportes.Postprint (published version

Norovirus outbreaks in long-term care facilities in Catalonia from 2017 to 2018

Norovirus is the leading cause of outbreaks of acute viral gastroenteritis. We carried out this study to investigate outbreaks in long-term care facilities reported in 2017 and 2018 in Catalonia (Spain). The characteristics of the centers, exposed persons and the genogroups responsible were analyzed. Viral loads were estimated. The attack rate (AR) of the outbreaks studied, and the rate ratio (RR) and the odds ratio (OR) and their 95% confdence intervals as measures of association were calculated. The mean cycle thresholds were compared using the t-test for independent means. We included 30 outbreaks (4631 exposed people). The global AR was 25.93%. The RR of residents vs. staf was 2.28 (95% CI 2.0-2.6). The RR between AR in residents with total or severe dependence vs. residents with moderate, low or no-dependence was 1.23 (95% CI 1.05-1.45). The AR were higher in smaller centers than in larger ones (38.47% vs. 19.25% and RR 2; 95% CI 1.82-2.2). GII was responsible for 70% of outbreaks. No association was found between the genogroup and presenting symptoms (OR 0.96; 95% CI 0.41-2.26). Viral loads were higher in symptomatic than in asymptomatic patients (p = 0.001)

Dimethylglyoxime modified screen-printed electrodes for nickel determination

This work reports the development of a dimethylglyoxime (DMG) modified sensor in which the complexing agent was successfully immobilized by drop-casting onto a screen-printed carbon electrode support (SPCE). The experimental conditions for the preparation of the DMG-SPCE sensor were optimized by means of a D-optimal design, and the built sensors were analytically evaluated for the determination of Ni(II) by adsorptive stripping voltammetry (AdSV). Its analytical performance suggests its suitability for the determination of Ni(II)-ions by AdSV at concentration levels of μg L-1 (LOD of 2.3 μg L-1, linear range from 7.6 to 200 μg L-1). Finally, the applicability of the developed sensor was assessed by the determination of trace levels of Ni(II) by AdSV in a wastewater reference material with a very high reproducibility (0.005 %) and good trueness (0.1 %)

Characterization and classification of Spanish paprika (Capsicum annuum L.) by liquid chromatography coupled to electrochemical detection with screen-printed carbon-based nanomaterials electrodes

Screen-printed electrodes based on graphite, carbon nanotubes, carbon nanofibers, and graphene were tested as amperometric detectors for the determination of polyphenols by high performance liquid chromatography (HPLC). The chromatographic performance as well as the obtained sensitivity, detection and quantification limits suggest that carbon nanofibers modified screen-printed electrode (SPCE-CNF) is the amperometric sensor that provides the best analytical performance. Upon this confirmation, chromatographic data obtained using SPCE-CNF were exploited by means of linear discriminant analysis to successfully characterize and classify 96 Spanish paprika (Capsicum annuum L.) samples with protected designation of origin: from La Vera (including sweet, bittersweet and spicy types) and from Murcia (including sweet and spicy types)

Determination of HPLC-UV fingerprints of Spanish paprika (Capsicum annuum L.) for its classification by linear discriminant analysis

The development of a simple HPLC-UV method towards the evaluation of Spanish paprika' phenolic profile and their discrimination based on the former is reported herein. The approach is based on C18 reversed-phase chromatography to generate characteristic fingerprints, in combination with linear discriminant analysis (LDA) to achieve their classification. To this aim, chromatographic conditions were optimized so as to achieve the separation of major phenolic compounds already identified in paprika. Paprika samples were subjected to a sample extraction stage by sonication and centrifugation; extracting procedure and conditions were optimized to maximize the generation of enough discriminant fingerprints. Finally, chromatograms were baseline corrected, compressed employing fast Fourier transform (FFT), and then analyzed by means of principal component analysis (PCA) and LDA to carry out the classification of paprika samples. Under the developed procedure, a total of 96 paprika samples were analyzed, achieving a classification rate of 100% for the test subset (n=25)