597 research outputs found

    Un currículo para el estudio de la historia de la ciencia en Secundaria : la experiencia del Seminario Orotava de Historia de la Ciencia

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    The curricula of two disciplines on History of Science at the High School level have been elaborated as part of the activities of a singular experience, Seminario Orotava de Historia de la Ciencia. The philosophy of the design considers science as an essential part of culture and interdisciplinarity as the most fitted method of teaching and learnign in a significative way

    Evolution induced by dry minor mergers onto fast-rotator S0 galaxies

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    We analysed collisionless N-body simulations of intermediate and minor dry mergers onto S0s to test whether these mergers can generate S0 galaxies with kinematics intermediate between fast and slow rotators. We find that minor mergers induce a lower decrease of the global rotational support than encounters of lower mass ratios, which results in S0s with properties intermediate between fast and slow rotators. The resulting remnants are intrinsically more triaxial, less flattened, and span the whole range of apparent ellipticities up to ϵe0.8\epsilon_\mathrm{e} \sim 0.8. They do not show lower apparent ellipticities in random projections than initially; on the contrary, the formation of oval distortions and the disc thickening increase the percentage of projections at 0.4<ϵe<0.70.4 < \epsilon_\mathrm{e} < 0.7. In the experiments with S0b progenitor galaxies, minor mergers tend to spin up the bulge and to decrease slightly its intrinsic ellipticity, whereas in the cases of primary S0c galaxies they keep the rotational support of the bulge nearly constant and decrease significantly its intrinsic ellipticity. The remnant bulges remain nearly spherical (B/AC/A>0.9B/A \sim C/A > 0.9), but exhibit a wide range of triaxialities (0.20<T<1.000.20 < T < 1.00). In the plane of global anisotropy of velocities (δ\delta) vs. intrinsic ellipticity (ϵe,intr\epsilon_\mathrm{e,intr}), some of our models extend the linear trend found in previous major merger simulations towards higher ϵe,intr\epsilon_\mathrm{e,intr} values, while others depart from it. This is consistent with the wide dispersion exhibited by real S0s in this diagram compared with ellipticals, which follow the linear trend drawn by major merger simulations. The different trends exhibited by ellipticals and S0 galaxies in the δ\delta - ϵe\epsilon_\mathrm{e} diagram may be pointing to the different role played by major mergers in the build-up of each morphological type.Comment: Corrected typos. 20 pages, 14 figures. Accepted for publishing in A&

    A Distributed Solution to Synchronous Multiparty Interaction

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    Multiparty interactions are the key to describe problems where three or more processes need to collaborate simultaneously in order to solve a problem, and this paper aims to show the way we have implemented this mechanism in a network computer. The main feature of our solution is that it is not bound up with the underlying network, so it is highly portable. We also report some experimental results that showthat our prototype performs quite well on low cost computers

    Enhanced exchange and reduced magnetization of Gd in an Fe/Gd/Fe trilayer

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    5 páginas, 6 figuras.-- PACS number(s): 75.70.−i, 75.47.De, 75.60.EjThe exchange interaction of Gd adjacent to Fe has been characterized by transport measurements on a double spin valve with a Fe/Gd/Fe trilayer as the middle layer. Our measurements show that the ferromagnetism of the Gd is enhanced by the presence of the Fe, and it remains ferromagnetic over its Curie temperature up to a thickness no smaller than 1 nm adjacent to the Fe. This thickness is more than double what has been reported before. Additionally, the saturation magnetization of the thin Gd layer sandwiched in Fe was found to be half of its bulk value. This reduced magnetization does not seem to be related to the proximity of Fe but rather to the incomplete saturation of Gd even for very high fields.This work was partially supported by Project Nos. MAT2008-02770/NAN and MAT2009-08771 from the SpanishMinisterio deCiencia e Innovaci´on. M. Romerawas funded through the FPU Fellowship No. AP2007-00464.Peer reviewe

    The Interstitial Lymphatic Peritoneal Mesothelium Axis in Portal Hypertensive Ascites: When in Danger, Go Back to the Sea

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    Portal hypertension induces a splanchnic and systemic low-grade inflammatory response that could induce the expression of three phenotypes, named ischemia-reperfusion, leukocytic, and angiogenic phenotypes.During the splanchnic expression of these phenotypes, interstitial edema, increased lymph flow, and lymphangiogenesis are produced in the gastrointestinal tract. Associated liver disease increases intestinal bacterial translocation, splanchnic lymph flow, and induces ascites and hepatorenal syndrome. Extrahepatic cholestasis in the rat allows to study the worsening of the portal hypertensive syndrome when associated with chronic liver disease. The splanchnic interstitium, the mesenteric lymphatics, and the peritoneal mesothelium seem to create an inflammatory pathway that could have a key pathophysiological relevance in the production of the portal hypertension syndrome complications. The hypothetical comparison between the ascitic and the amniotic fluids allows for translational investigation. From a phylogenetic point of view, the ancestral mechanisms for amniotic fluid production were essential for animal survival out of the aquatic environment. However, their hypothetical appearance in the cirrhotic patient is considered pathological since ultimately they lead to ascites development. But, the adult human being would take advantage of the potential beneficial effects of this “amniotic-like fluid” to manage the interstitial fluids without adverse effects when chronic liver disease aggravates

    Ellagitannin-rich bioactive extracts of Tuberaria lignosa: insights into the radiation-induced effects in the recovery of high added-value compounds

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    Ellagitannins are polyphenols responsible for a number of bioactivities and health-promoting effects. These industrially important molecules can be affected by post-harvest treatments and recovery processes, but little is known about the irradiation-induced effects on their integrity, bioactivity and extractability. Herein, the impact of gamma radiation on the production of ellagitannin-rich extracts was investigated using Tuberaria lignosa as a case study. These effects were compared with those induced in flavonoids and organic acids. The extracts were particularly rich in hydrophilic antioxidants (measured by in vitro assays). The recovery of different phytochemicals was favoured by longer extraction times. Ellagitannins (mainly punicalagin derivatives) were extracted better from samples irradiated at 5 kGy and were not significantly affected by the 10 kGy dose. However, the total contents of flavonoids and organic acids were decreased by the consequent increase in irradiation dose. Therefore, this study supports the use of gamma radiation for processing T. lignosa, aiming to obtain ellagitannin-rich bioactive extracts.The authors are grateful to the PRODER research project no. 53514 AROMAP for financial support of the work; to the Foundation for Science and Technology (FCT) of Portugal and FEDER under Programme PT2020 for financial support to CIMO (UID/AGR/00690/2013); to FCT/MEC for financial support to REQUIMTE/LAQV (UID/QUI/50006/2013 - POCI/01/ 0145/FERDER/007265); to FCT for the grants attributed to J. Pinela (SFRH/BD/92994/2013; funded by the European Social Fund and MEC through Programa Operacional Capital Humano (POCH)) and L. Barros (SFRH/BPD/107855/2015); to the Xunta de Galicia for financial support to M. A. Prietoinfo:eu-repo/semantics/publishedVersio

    Gamma radiation-induced effects on the recovery of pharmacologically active polyphenols from tuberaria lignosa medicinal plant

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    Ionizing radiation has been used for many years as a safer and environmentally friendly alternative comparatively to chemical fumigants to decontaminate medicinal plants and other food commodities [1]. Perennial spotted rockrose (Tuberaria lignosa (Sweet) Samp.) is a highly quoted medicinal plant in the northeast region of Portugal rich in ellagitannin derivatives [2,3]. As polyphenols, these compounds play an important role in human nutrition and display several biological effects, including antioxidant, anti-inflammatory, antitumor, antibacterial, and anti-HIV replication activities [2-4]. However, little is known about the impact of ionizing radiation on the integrity and extractability of these high added-value compounds. This work aimed to investigate the effects of γ-rays irradiation on the extraction and/or degradation kinetics of ellagitannins from T. lignosa aerial parts. The plant material was submitted to irradiation doses up to 10 kGy in a cobalt-60 experimental chamber. Then, the non-irradiated and irradiated plant material was submitted to different solid-liquid extractions, according to a three-level full factorial design, using boiling water as extraction solvent. The ellagitannins were analyzed in a high-performance liquid chromatography (HPLC) system connected to a diode array detector (DAD) and a mass spectrometer (MS). Punicalin, punicalagin isomers, and punicalagin gallate isomers were the most abundant compounds. In general, the extractability of this group of phytochemicals was improved by the irradiation treatment (5 kGy) and longer extraction times (10 min). In addition, the 10 kGy dose did not induced adverse effects. In conclusion, this study demonstrated the suitability of γ-rays irradiation for preserving or improving the extractability of pharmacologically active compounds from T. lignosa aerial parts.The authors are grateful to the Foundation for Science and Technology (FCT) of Portugal and FEDER, under Programme PT2020, for financial support to CIMO (UID/AGR/00690/2013); to FCT/MEC for financial support to REQUIMTE/LAQV (UID/QUI/50006/2013 - POCI/01/0145/FEDER/007265); to FCT for the J. Pinela grant (SFRH/BD/92994/2013) and L. Barros contract; to the Xunta de Galicia for financial support to M. A. Prieto; C2TN (RECI/AAG-TEC/0400/2012 and UID/Multi/04349/2013 projects); International Atomic Energy Agency (IAEA - CRP D61024 - DEXAFI). The authors are also grateful to the Interreg España-Portugal for financial support through the Project 0377_Iberphenol_6_E.info:eu-repo/semantics/publishedVersio

    Valorização de produtos de montanha pela utilização de tecnologias de processamento não convencionais

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    Os vegetais embalados prontos a comer têm tido uma crescente aceitação por parte do consumidor por atenderem aos requisitos contemporâneos de conveniência, segurança e salubridade. O crescimento deste setor tem levado à introdução de novos produtos e à adoção de tecnologias de conservação mais eficientes, seguras e sustentáveis [1]. O consumidor procura também alimentos com características organoléticas diferenciadas das dos alimentos habitualmente consumidos diariamente. A recuperação do uso de Rumex induratus Boiss. & Reut. (azedas) e Nasturtium officinale R. Br. (agrião) poderá responder a esta procura, aliando garantia de qualidade e inovação. Visto a maioria dos tratamentos convencionais ser ineficaz em assegurar segurança sem comprometer a qualidade, e dada a preocupação em torno dos agentes químicos vulgarmente utilizados, a irradiação de alimentos e o embalamento em atmosfera modificada têm emergido como alternativas seguras e eficazes [1-4]. Neste sentido, este estudo teve como objetivo avaliar a eficácia de diferentes atmosferas de embalamento e de diferentes doses de radiação ionizante na conservação da qualidade destas espécies durante o armazenamento refrigerado. O uso sustentável de produtos vegetais para a recuperação de biomoléculas ou produção de ingredientes funcionais de valor acrescentado é uma estratégia útil que pode ajudar a enfrentar os desafios societais deste século. Atualmente é originada uma grande quantidade de resíduos de tomate (Lycopersicon esculentum Mill.) fresco durante as várias etapas do seu ciclo produtivo, desde a cultura até ao armazenamento e venda [5]. Estes resíduos são ricos em licopeno e vitaminas, mas também em compostos fenólicos [6,7]. Estes compostos bioativos estão envolvidos na prevenção de várias patologias humanas e são de elevada importância para a indústria alimentar, farmacêutica e cosmética. Visto os métodos convencionais utilizados para a extração destas biomoléculas apresentarem várias desvantagens, novas tecnologias mais eficientes e sustentáveis têm vindo a ser adotadas. Neste sentido, este trabalho teve como objetivo otimizar as condições de extração assistida por tecnologia micro-ondas de antioxidantes hidrofílicos e lipofílicos e dos ácidos fenólicos e flavonoides maioritários da variedade de tomate redondo utilizando a metodologia de superfície de resposta (RSM)

    Development of a questionnaire to measure health-related quality of life (HRQoL) in patients with atrial fibrillation (AF-QoL)

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    <p>Abstract</p> <p>Background</p> <p>The Health-Related Quality of Life (HRQoL) assessment in atrial fibrillation (AF) patients has traditionally been carried out in a poorly standardised fashion, or via the use of non disease-specific HRQoL questionnaires. The development of a HRQoL questionnaire with a good measuring performance will allow for a standardised assessment of the impact of this disease on the patient's daily living.</p> <p>Methods</p> <p>A bibliography review was conducted to identify the most relevant domains of daily living in AF patients. Subsequently, a focus group was created with the aid of cardiologists, and 17 patients were interviewed to identify the most-affected HRQoL domains. A qualitative analysis of the interview answers was performed, which was used to develop a pilot questionnaire administered to a 112-patient sample. Based on patient responses, an analysis was carried out following the statistical procedures defined by the Classical Test Theory (CTT) and the Item Response Theory (IRT). Reliablility was assessed via Cronbach's coefficient alpha and item-total score correlations. A factorial analysis was performed to determine the number of domains. For each domain, a Rasch analysis was carried out, in order to reduce and stand hierarchically the questionnaire items.</p> <p>Results</p> <p>By way of the bibliography review and the expert focus group, 10 domains were identified. The patient interviews allowed for the identification of 286 items that later were downsized to 40 items. The resultant preliminary questionnaire was administered to a 112-patient sample (pilot study). The Rasch analysis led to the definition of two domains, comprising 7 and 11 items respectively, which corresponded to the psychological and physical domains (18 items total), thereby giving rise to the initial AF-QoL-18 questionnaire. Cronbach's coefficient alpha was acceptable (0.91).</p> <p>Conclusion</p> <p>An initial HRQoL questionnaire, AFQoL-18, has been developed to assess HRQoL in AF patients.</p

    Susceptibility and transcriptomic response to plasma-activated water of Listeria monocytogenes planktonic and sessile cells

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    [EN] Plasma-Activated Water (PAW) was generated from tap water using a surface dielectric barrier discharge at different discharge power (26 and 36 W) and activation time (5 and 30 min). The inactivation of a three-strain Listeria monocytogenes cocktail in planktonic and biofilm state was evaluated. PAW generated at 36 W-30 min showed the lowest pH and the highest hydrogen peroxide, nitrates, nitrites contents and effectiveness against cells on planktonic state, resulting in 4.6 log reductions after a 15-min treatment. Although the antimicrobial activity in biofilms formed on stainless steel and on polystyrene was lower, increasing the exposure time to 30 min allowed an inactivation >4.5 log cycles. The mechanisms of action of PAW were investigated using chemical solutions that mimic its physico-chemical characteristics and also RNA-seq analysis. The main transcriptomic changes affected carbon metabolism, virulence and general stress response genes, with several overexpressed genes belonging to the cobalamin-dependent gene cluster.S
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