952 resultados para Anàlisi instrumental


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In this study, Evernia prunastri, a lichen growing in its natural habitat in Morocco was analysed for the concentration of five heavy metals (Fe, Pb, Zn, Cu and Cr) from eleven sites between Kenitra and Mohammedia cities. The control site was Dar Essalam, an isolated area with low traffic density and dense vegetation. In the investigated areas, the concentration of heavy metals was correlated with vehicular traffic, industrial activity and urbanization. The total metal concentration was highest in Sidi Yahya, followed by Mohammedia and Bouznika. The coefficient of variation was higher for Pb and lower for Cu, Zn and Fe. The concentrations of most heavy metals in the thalli differed significantly between sites (p<0.01). Principal component analysis (PCA) revealed a significant correlation between heavy metal accumulation and atmospheric purity index. This study demonstrated also that the factors most strongly affecting the lichen flora were traffic density, the petroleum industry and paper factories in these areas. Overall, these results suggest that the index of atmospheric purity and assessment of heavy metals in lichen thalli are good indicators of the air quality at the studied sites.

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Xanthoria parietina, common foliose lichen, growing in its natural habitat, was analysed for the concentration of five heavy metals (Fe, Cr, Zn, Pb and Cu) from different forest sites of North East of Morocco (Kenitra, Sidi Boughaba, Mkhinza, Ceinture Verte near Temara city, Skhirate, Bouznika and Mohammedia). The quantification was carried out by inductively coupled plasma - atomic emission spectrometry (ICP-AES). Results were highly significant p<0,001. The concentration of metals is correlated with the vehicular activity and urbanization. The total metal concentration is highest at the Kenitra area, followed by Ceinture Verte site near Temara city, which experience heavy traffic throughout the year. Scanning electron microscopy (SEM) of particulate matter on lichen of Xanthoria parietina was assessed as a complementary technique to wet chemical analysis for source apportionment of airborne contaminant. Analysis revealed high level of Cu, Cr, Zn and Pb in samples near roads.  

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Social networks have increasingly become a showcase where the media can be promoted. Like many other media, radio stations have made use of social networks to promote themselves in a better way and, sometimes, to keep more feedback with their listeners. But not all programs make the same use and not all of them have managed to reach in the same way his followers. This article discusses the consolidation in the social networks of the major radio sports programs in Spain. Through a comparative analysis between 2010 and 2015, throughout the text, the authors have tried to observe the evolution of the programs and, at the same time, to establish comparisons between the followers that these programs have on social networks and the number of listeners as EGM.

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En el artículo se analizan las posibilidades que tiene el crowfunding (CF) para financiar el audiovisual. Se explica el modelo de financiación del CF y se indican las distintas ventajas que reporta para el promotor este modelo de financiación alternativa. Además se exponen ampliamente las principales características del proceso de CF seguido para financiar el cortometraje Juan y la nube (que se alzó con el Goya al Mejor corto de animación en el año 2015). Se comentan también los principales motivos que llevan a los mecenas a financiar los proyectos

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Definición de la etapa de crisis del aparato cinematográfico franquista, llamada aquí “Período Oscuro” (1969-1975), discusión de la etiqueta de subgéneros aplicada al cinema bis de la época, y caracterización histórica del thriller español y de sus corrientes estéticas y conceptuales internas en dicho período. La acotación del período 1969-1975 es clarificada previamente ante el vacío historiográfico al respecto. Se caracteriza la crisis que tiene lugar en el “Período Oscuro”, desde su comienzo oficial en 1969, que supuso el definitivo cierre de las políticas proteccionistas emprendidas por el Director General de Cinematografía García Escudero en 1962. Después se define y discute la etiqueta de subgéneros aplicada tradicionalmente al cine español de género de bajo presupuesto. Luego, se especifican, definen y analizan las diversas categorías dentro del thriller español de 1969-1975: se trata de categorías temáticas y argumentales, estéticas, o bien relacionadas con corrientes internacionales del policíaco europeo. Por último, se extraen las conclusiones pertinentes.

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The purpose of this study was to mathematically characterize the effects of defined experimental parameters (probe speed and the ratio of the probe diameter to the diameter of sample container) on the textural/mechanical properties of model gel systems. In addition, this study examined the applicability of dimensional analysis for the rheological interpretation of textural data in terms of shear stress and rate of shear. Aqueous gels (pH 7) were prepared containing 15% w/w poly(methylvinylether-co-maleic anhydride) and poly(vinylpyrrolidone) (PVP) (0, 3, 6, or 9% w/w). Texture profile analysis (TPA) was performed using a Stable Micro Systems texture analyzer (model TA-XT 2; Surrey, UK) in which an analytical probe was twice compressed into each formulation to a defined depth (15 mm) and at defined rates (1, 3, 5, 8, and 10 mm s-1), allowing a delay period (15 s) between the end of the first and beginning of the second compressions. Flow rheograms were performed using a Carri-Med CSL2-100 rheometer (TA Instruments, Surrey, UK) with parallel plate geometry under controlled shearing stresses at 20.0°?±?0.1°C. All formulations exhibited pseudoplastic flow with no thixotropy. Increasing concentrations of PVP significantly increased formulation hardness, compressibility, adhesiveness, and consistency. Increased hardness, compressibility, and consistency were ascribed to enhanced polymeric entanglements, thereby increasing the resistance to deformation. Increasing probe speed increased formulation hardness in a linear manner, because of the effects of probe speed on probe displacement and surface area. The relationship between formulation hardness and probe displacement was linear and was dependent on probe speed. Furthermore, the proportionality constant (gel strength) increased as a function of PVP concentration. The relationship between formulation hardness and diameter ratio was biphasic and was statistically defined by two linear relationships relating to diameter ratios from 0 to 0.4 and from 0.4 to 0.563. The dramatically increased hardness, associated with diameter ratios in excess of 0.4, was accredited to boundary effects, that is, the effect of the container wall on product flow. Using dimensional analysis, the hardness and probe displacement in TPA were mathematically transformed into corresponding rheological parameters, namely shearing stress and rate of shear, thereby allowing the application of the power law (??=?k?n) to textural data. Importantly, the consistencies (k) of the formulations, calculated using transformed textural data, were statistically similar to those obtained using flow rheometry. In conclusion, this study has, firstly, characterized the relationships between textural data and two key instrumental parameters in TPA and, secondly, described a method by which rheological information may be derived using this technique. This will enable a greater application of TPA for the rheological characterization of pharmaceutical gels and, in addition, will enable efficient interpretation of textural data under different experimental parameters.

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This paper presents and analyzes the first literary-journalistic chronicle writen and published by Miguel Hernández: “Defensa de Madrid. Madrid y las ciudades de Retaguardia”, during the Spanish Civil War (1936-1939). This chronicle is the first one of a series establishing a new and personal type of journalism: literary chronicles –poetical and political-. Miguel Hernandez published his masterpieces in different newspapers as a war reporter, with his own name and with a pen-name, playing roles of director and political commissar in different newspapers in the war-trenches. Thematically, this first article shows his personal and political engagement, as well as his desire and strategy to protect the capital city of Spain: Madrid. Methodologically, the analysis is an approached to linguistics in social sciences, which presents some of the personal characteristics and style of the chronist Miguel Hernández. Thus, it becomes patent that the so-called New Journalism (narrative and literary), which flourished in the 70s, had already been deeply and efficiently practiced by Miguel Hernández 40 years before. That is the reason why Miguel Hernández deserves to be added to the well-known collective of chronicle writers that have already been rescued to this moment. His literary style and quality are installing him in a outstanding position as well as pioneer of the genre nowadays known as New Journalism that in his case, it is politically engaged

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Results of a fossil Coleoptera (beetle) fauna from a fen edge sequence from Hatfield Moors, Humberhead Levels, are presented. Mire ontogeny inferred from this location and others are discussed, particularly in the light of previous palynological and plant macrofossil investigations. Peat initiation across most of the site centres around 3000 cal BC, characterised by a Calluna-Eriophorum heath with areas of Pinus-Betula woodland. The onset of peat accumulation on the southern margins of the site was delayed until 1520-1390 cal BC and appears to overlap closely with a recurrence surface at a pollen site (HAT 2) studied by Brian Smith (1985, 2002) dated to 1610-1440 cal BC, suggesting that increased surface wetness may have caused mire expansion at this time. The faunas illustrate the transition from eutrophic and mesotrophic fen to ombrotrophic raised mire, although the significance of both Pinus- and Calluna-indicating species through the sequence suggests that heath habitats may have continued to be important. Elsewhere, this earlier phase of rich fen is lacking and mesotrophic mire developed immediately above nutrient poor sands, with ombrotrophic conditions indicated soon after. Correspondence analysis of the faunas provides valuable insights into the importance of sandy heath habitats on Hatfield Moors. The continuing influence of the underlying coversands suggests these may have been instrumental in mire ontogeny. The research highlights the usefulness of using Coleoptera to assess mire ontogeny, fluctuations in site hydrology and vegetation cover, particularly when used in conjunction with other peatland proxies. The significance of a suite of extinct beetle species is discussed with reference to forest history and climate change.

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A new approach to evaluating all multiple complex roots of analytical function f(z) confined to the specified rectangular domain of complex plane has been developed and implemented in Fortran code. Generally f (z), despite being holomorphic function, does not have a closed analytical form thereby inhibiting explicit evaluation of its derivatives. The latter constraint poses a major challenge to implementation of the robust numerical algorithm. This work is at the instrumental level and provides an enabling tool for solving a broad class of eigenvalue problems and polynomial approximations.

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This article explores alternative interpretations of the meaning and method of urban policy evaluation within the European Union (EU) Structural Funds. Using the EU URBAN Community Initiative Programme 1994-1999 it draws a distinction between 'instrumental' techniques that are primarily concerned with performance and efficiency measures and 'interpretative' approaches that stress the need to explore power relationships in the development and delivery of spending programmes. Empirically, it reflects on the interpretation of EU guidance and the MEANS (Means for Evaluating Actions of a Structural Nature) Collection to evaluate the Derry/Londonderry (UK) URBAN Sub-programme 1994-1999. The analysis concludes by emphasizing the need to ensure that urban policy evaluation is consistent with the broader social turn in the scope and content of regeneration programmes.

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This article argues that productive work represents a mode of human flourishing unfortunately neglected in much current political theorizing. Focusing on Habermasian critical theory, I contend that Habermas’s dualist theory of society, on account of the communicative versus instrumental reason binary which underpins it, excludes work and the economy from ethical reflection. To avoid this uncritical turn, we need a concept of work that retains a core emancipatory referent. This, I claim, is provided by Alasdair MacIntyre’s notion of ‘practice’. The notion of ‘practice’ is significant in suggesting an alternative conception of human productivity that is neither purely instrumental nor purely communicative, but rather both simultaneously, a form of activity which issues in material products and yet presumes a community of workers engaged in intersubjective self-transformation. However, we can endorse MacIntyre’s notion of ‘practice’ only if we reject his totalizing anti-modernism and insist on the emancipatory potentialities of modern institutions.

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Recent fully relativistic calculations of radiative rates and electron impact excitation cross-sections for FeXIII are used to generate emission-line ratios involving 3s23p2-3s3p3 and 3s23p2-3s23p3d transitions in the 170-225 and 235-450 Å wavelength ranges covered by the Solar Extreme-Ultraviolet Research Telescope and Spectrograph (SERTS). A comparison of these line ratios with SERTS active region observations from rocket flights in 1989 and 1995 reveals generally very good agreement between theory and experiment. Several new FeXIII emission features are identified, at wavelengths of 203.79, 259.94, 288.56 and 290.81 Å. However, major discrepancies between theory and observation remain for several FeXIII transitions, as previously found by Landi and others, which cannot be explained by blending. Errors in the adopted atomic data appear to be the most likely explanation, in particular for transitions which have 3s23p3d1D2 as their upper level. The most useful FeXIII electron-density diagnostics in the SERTS spectral regions are assessed, in terms of the line pairs involved being (i) apparently free of atomic physics problems and blends, (ii) close in wavelength to reduce the effects of possible errors in the instrumental intensity calibration, and (iii) very sensitive to changes in Ne over the range 108-1011cm-3. It is concluded that the ratios which best satisfy these conditions are 200.03/202.04 and 203.17/202.04 for the 170-225 Å wavelength region, and 348.18/320.80, 348.18/368.16, 359.64/348.18 and 359.83/368.16 for 235-450 Å.

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Results of the search of the periodic changes of the 530.3 nm line intensity emitted by selected structures of the solar corona in the frequency range 1-10 Hz are presented. A set of 12 728 images of the section of the solar corona extending from near the north pole to the south-west were taken simultaneously in the 530.3 nm ("green") line and white-light with the Solar Eclipse Coronal Imaging System (SECIS) during the 143-seconds- long totality of the 1999 August 11 solar eclipse observed in Shabla, Bulgaria. The time resolution of the collected data is better than 0.05 s and the pixel size is approximately 4 arcsec. Using classical Fourier spectral analysis tools, we investigated temporal changes of the local 530.3 nm coronal line brightness in the frequency range 1-10 Hz of thousands of points within the field of view. The various photometric and instrumental effects have been extensively considered. We did not find any indisputable, statistically significant evidence of periodicities in any of the investigated points (at significance level alpha = 0.05).

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In this paper we analyze the representation of the body in blogs by women with breast cancer. Taking into account both texts and images, we study the representation of the body on the basis of the body problems proposed by Frank (1995): control, body-relatedness, other-relatedness and desire. In the blogs studied we find a desiring and dyadic body, which is understood as part of a network of affection and care. The diagnosis of cancer can generate both dissociation, when the body is experienced as a threat, and association, a wish to be connected to it. In relation to control, a clear will of predictability is observed but traces of assumption of contingency also appear.

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The aim of this paper is to recognize the images that prospective elementary school teachers have about citizenship and citizenship education in school. The qualitative methodology with an ethnographic approach is used for that deep interview of ethnographic kind and analysis of institutional documents, for example, curricula, course syllabus and graduated profi le. The revision of documents helps to a better understanding of discourses. The analysis of the corpus obtained after the application of the paradigm of codifi cation proposed in the established theory. As the principal fi ndings we way point out that the concept of citizens that is common among prospective elementary school teachers is reduced to the school environment because they consider that the promotion of citizenship helps to the incorporation of children to society, thus reproducing a propaedeutic view of education.