Physicochemical characterization and antimicrobial activity against Erwinia amylovora, Erwinia vitivora, and Diplodia seriata of a light purple Hibiscus syriacus L. Cultivar

Phytochemicals are essential raw materials for the production of formulations that can be helpful in crop protection. In particular, Hibiscus spp., which are often used in traditional medicine, are rich in potential bioactive molecules. This study presents an analysis of the thermal, vibrational, and phytochemical characteristics of a light purple variety of Hibiscus syriacus, using thermal gravimetric and differential scanning calorimetry, Fourier-transform infrared spectroscopy, and gas chromatography-mass spectroscopy techniques. Further, with a view to its valorization, the antimicrobial activity of its extracts has been investigated in vitro against Erwinia amylovora (the phytopathogen responsible for fire blight in apples, pears, and some other members of the family Rosaceae), Erwinia vitivora (the causal agent of the “maladie d’Oléron” in grapevines), and Diplodia seriata (responsible for “Bot canker”). Higher heating values and thermal features showed similarities with kenaf biomass. The main compounds identified in the hydro-methanolic extracts were: in flowers, 1-heptacosanol, heptacosane, 1-tetracosanol, hexadecenoic acid, 9,12,15-octadecatrienoic acid, and 9,12-octadecadienoic acid; and in leaves, the coumarin derivative 4,4,6,8-tetramethyl-2-chromanone, vitamin E, phytol, and sitosterol. MIC values of 500 and 375 μg·mL−1 were obtained against E. amylovora for flower and leaf extracts, respectively, upon conjugation with chitosan oligomers (to improve solubility and bioavailability). In the case of E. vitivora, MIC values of 250 and 500 μg·mL−1, respectively, were registered. Regarding the antifungal activity, EC90 values of 975.8 and 603.5 μg·mL−1, respectively, were found. These findings suggest that H. syriacus (cv. ‘Mathilde’) may be a promising source of antimicrobials for agriculture

Structural, textural and acidic properties of Cu-, Fe- and Cr-doped Ti-pillared montmorillonites

Montmorillonite has been treated with Ti-based solutions, alone or doped with Cu2 +, Fe3 + or Cr3 + cations, yielding new intercalated solids, which have been calcined at various temperatures to test the stability of the so-formed pillars. The solids calcined at 500 °C were fully characterized by chemical analysis, X-ray diffraction, FT-IR spectroscopy, thermal analyses, nitrogen adsorption and acidity evaluation. The evolution of the specific surface area, porosity and acidic properties is discussed, analysing the effect of pillaring and doping procedures on these propertie

A new method for nocturnal aerosol measurements with a lunar photometer prototype

This paper presents the preliminary results of nocturnal Aerosol Optical Depth (τa) and Angström Exponent (α) obtained from a new lunar photometer prototype, trade name Cimel CE-318U. Due to the variation of the moon's illumination inherent to the lunar cycle, the typical Langley-plot Method used in solar photometry to calibrate these instruments cannot be applied. In this paper, we propose three different methods to carry out the lunar-photometer calibration. In order to validate the results, we have selected three events which encompass seven nights and ten days under different atmospheric conditions, including several saharan dust intrusions episodes. Method#1 is introduced in this work as a modification of the usual Langley Method. This technique, called Lunar-Langley Method, requires the extraterrestrial irradiances from a lunar irradiance model, providing similar accuracies on τa to those of AERONET (±0.01-0.02). It makes comparable daytime and nighttime measurements. Method#2 consists of transferring the current calibration from a master used by sunphotometers. Its results are again within the limit of accuracy expected for the instrument. Method#3 uses an integrating sphere and the methodology proposed by Li et al. (2008) to determine sky calibration coefficients (Cj) and the instrument's solid angle field-of-view (Ω), respectively. We observe significant τa differences between Method#1 and #3 (up to 0.07), which might be attributed to the errors propagation in Method#3. The good results obtained from the comparison against a second CE-318U prototype, and against daytime data from a Precision Filter Radiometer (PFR), constitute a valuable assessment of CE-318U performance. Results of α and its spectral variation (δα) show good agreement between daytime and nighttime, being able to identify the aerosol properties associated with each event. © Author(s) 2013

Towards domestic cooking efficiency: A case study on burger pan frying using experimental and computational results

It is well known that the use of efficient domestic cooking appliances and equipment can not only save energy, but also improve the quality of the food being prepared. This work raises the question of whether cooking procedures can also contribute to this energy efficiency. Focusing on burger pan frying, experimental data were used to develop a model able to predict cooking outcomes under different power levels supplied by an induction hob. The proposed model takes into account not only the heat consumed by water evaporation in the contact region but also the shrinkage process of the hamburger. A new formulation based on the multiplicative decomposition of the strain deformation gradient is proposed to describe the observed decoupling between weight and volume loss during the process. The model properly predicts temperature, moisture loss and shrinkage, and allows elucidation of the effects of supplying different amounts of energy on the final water content

¿Qué opinan los futuros maestros sobre el aprendizaje de las ciencias a través de la indagación y sobre sus necesidades formativas?

The application of an open-ended questionnaire allows us to detect some ideas about inquiry in preservice Primary teachers. A first analysis allows us to categorize the type of answers. In general, the majority of students ask for more theoretical contents about science, since they are not confidence in being involved in science teaching without this background. A great scattering of answers appears when students are asked for inquiry in the Primary classrooms. Finally, no coherent answers are detected when students declare that they want to learn “more scientific contents” (90%), whereas less than 50% of them would like to be taught about this issue

A new method for nocturnal aerosol measurements with a lunar photometer prototype

This paper presents the preliminary results of nocturnal Aerosol Optical Depth (τa) and Angström Exponent (α) obtained from a new lunar photometer prototype, trade name Cimel CE-318U. Due to the variation of the moon's illumination inherent to the lunar cycle, the typical Langley-plot Method used in solar photometry to calibrate these instruments cannot be applied. In this paper, we propose three different methods to carry out the lunar-photometer calibration. In order to validate the results, we have selected three events which encompass seven nights and ten days under different atmospheric conditions, including several saharan dust intrusions episodes. Method#1 is introduced in this work as a modification of the usual Langley Method.The Aeronet sunphotometer at Izana has been calibrated within ˜ AERONET-EUROPE TNA supported by the European Community – Research Infrastructure Action under the FP7 “Capacities” specific programme for Integrating Activities, ACTRIS Grant Agreement no. 262254

Two-step ATP-driven opening of cohesin head

The cohesin ring is a protein complex composed of four core subunits: Smc1A, Smc3, Rad21 and Stag1/2. It is involved in chromosome segregation, DNA repair, chromatin organization and transcription regulation. Opening of the ring occurs at the "head" structure, formed of the ATPase domains of Smc1A and Smc3 and Rad21. We investigate the mechanisms of the cohesin ring opening using techniques of free molecular dynamics (MD), steered MD and quantum mechanics/molecular mechanics MD (QM/MM MD). The study allows the thorough analysis of the opening events at the atomic scale: I) ATP hydrolysis at the Smc1A site, evaluating the role of the carboxy-terminal domain of Rad21 in the process; ii) the activation of the Smc3 site potentially mediated by the movement of specific amino acids; and iii) opening of the head domains after the two ATP hydrolysis events. Our study suggests that the cohesin ring opening is triggered by a sequential activation of the ATP sites in which ATP hydrolysis at the Smc1A site induces ATPase activity at the Smc3 site. Our analysis also provides an explanation for the effect of pathogenic variants related to cohesinopathies and cancer

Racismo, adolescencia e inmigración : reconocer y afrontar el racismo desde una perspectiva educativa

Este texto se presentó como comunicación al II Congreso Internacional de Etnografía y Educación: Migraciones y Ciudadanías. Universidad Autónoma de Barcelona, Barcelona, 5-8 Septiembre 2008.El racismo es una realidad compleja que, pese a estar presente en nuestra experiencia cotidiana, tanto dentro como fuera de los centros educativos, suele, sin embargo, ignorarse o negarse. Por ello, no resulta fácil hablar de racismo. Partiendo de esta reflexión nos planteamos en este proyecto acercarnos a las percepciones y experiencias de los adolescentes en torno a este fenómeno, a sus manifestaciones sutiles o explícitas, a sus implicaciones y consecuencias. Nuestra intención era tratar de comprender el fenómeno del racismo desde el punto de vista de los afectados, lo que implica básicamente: • Conocer la percepción de los jóvenes en relación con experiencias/situaciones de racismo. • Reconocer el racismo implícito en situaciones cotidianas, dentro y fuera del ámbito educativo. • Apreciar las dificultades con las que se encuentran jóvenes de diversos orígenes en su vida fuera y dentro del medio escolar. Pretendíamos dar voz a los chicos y chicas que viven, sufren o afrontan el racismo, con la finalidad de obtener información relevante para elaborar una Guía, dirigida al profesorado y adultos en general, y también a los propios adolescentes, que les ayudara a reconocer, comprender, interpretar y manejar situaciones de racismo desde una perspectiva educativa. Para ello contactamos con adolescentes cuyas características nos hicieron prejuzgar que podían formar parte de grupos que sufren cotidianamente el peso del racismo: sobre todo, chicas y chicos a los que solemos asociar con la categoría de «inmigrante». Los abordamos no sólo en los centros educativos, sino también en las calles y en los parques, allí donde pensamos que podían compartir sus ideas y experiencias en un clima de confianza. Descubrimos que los adolescentes tienen una visión clara y amplia del racismo y sus implicaciones, y son capaces de distinguir y narrar sus experiencias en torno a él. Así mismo, reclaman que se hable de racismo, que se trate abiertamente, que sus vivencias y percepciones se tengan en cuenta y reciban algún tipo de respuesta por parte de los adultos. Tomando como referente esta idea, construimos una Guía articulada en torno a sus narraciones, que trata de ofrecer ideas y propuestas que respondan a cinco cuestiones: qué es el racismo, por qué y para qué se da, cómo se produce, cómo se reproduce y cómo se afronta

Evaluation of ECA Gesture strategies for robust Human-Computer Interaction

Embodied Conversational Agents (ECAs) offer us the possibility to design pleasant and efficient human-machine interaction. In this paper we present an evaluation scheme to compare dialogue-based speaker authentication and information retrieval systems with and without ECAs on the interface. We used gestures and other visual cues to improve fluency and robustness of interaction with these systems. Our tests results suggest that when an ECA is present users perceive fewer system errors, their frustration levels are lower, turn-changing goes more smoothly, the interaction experience is more enjoyable, and system capabilities are generally perceived more positively than when no ECA is present. However, the ECA seems to intensify the users' privacy concerns

Phytochemical Screening and Antibacterial Activity of Taxus baccata L. against Pectobacterium spp. and Dickeya chrysanthemi

The yew tree (Taxus baccata L.) is considered in folklore a symbol of immortality due to its qualities of longevity and regeneration. Despite its poisonous reputation, the yew tree has a long history of medicinal use, particularly in the form of extracts from its leaves and bark. In the work presented herein, gas chromatography–mass spectrometry (GC–MS) chemical profiling was applied to the aqueous ammonia/hydromethanolic extracts of several plant organs of T. baccata, leading to the identification of different bioactive compounds than those previously characterized by high-performance liquid chromatography with tandem mass spectrometry (HPLC–MS/MS) in other extraction media. The leaf aqueous ammonia extract was rich in 2-hexylthiophene and 3-O-methyl-d-fructose; 9-octadecenoic and hexadecanoic acid were the main constituents of the bark aqueous ammonia extract; and the fruit hydromethanolic extract contained methyl 2-O-methyl-α-d-xylofuranoside, 1,3-dioxolane derivatives, and erysimoside. The antimicrobial activity of the extracts was assayed against four bacterial pathogens responsible for the soft rot and blackleg diseases of potatoes, viz. Pectobacterium carotovorum subsp. carotovorum, Pectobacterium atrosepticum, Pectobacterium parmentieri, and Dickeya chrysanthemi, resulting in minimum inhibitory concentration (MIC) values as low as 187 μg·mL−1. Bioassays on potato slices confirmed the efficacy of the leaf extract at this dose when applied as a preventive treatment before artificial inoculation with P. carotovorum subsp. carotovorum. In view of this high activity, these extracts may find application in the integrated pest management of soft rot Pectobacteriaceae (SRP) diseases.Publishe