372 research outputs found

    World caf\ue9 method to engage smart energy-district project partners in assessing urban co-benefits

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    Urban energy-district projects introduce outstanding technological innovation in buildings and energy systems increasing sustainability in city neighborhoods. Such projects generate additional co-benefits for the city beyond changes in physical elements and development of social and institutional relationships (e.g. local employment, environmental quality, public health, property values, innovation attitude, etc.). Since exceeding main declared goals or not always clearly foreseen in the early project phase, these co-benefits are often not properly understood and considered. However, only their explicit recognition will make possible their inclusion in the assessment of the whole project\u2019s performance. From these considerations, this study faces the issue of engaging project partners in assessing co-benefits in order to consider a broad spectrum of relevant, positive effects in the evaluation process. Group knowledge and group thinking of this complex topic are investigated through the world caf\ue9 method, providing an atmosphere of trust and open discussions among participants. This empirical work lays the foundations to go beyond the mere economic measure as the sole criterion for assessing project effects, also including changes in end-user behavior and intangible asset

    Voluntary stopping of eating and drinking in Switzerland from different points of view : protocol for a mixed-methods study

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    “To die with dignity” has reached the significance of a core value in democratic societies. Based on this unconditional value, people require autonomy and care. "Voluntary stopping of eating and drinking" (VSED) represents an alternative to assisted suicide because no one else is involved in the action of death fastening, even though from outside, it might be considered as an extreme form of passive euthanasia. However, there are no data available about the prevalence and frequency of either explicit VSED or the implicit reduction of food and liquid in Switzerland. The responsible and independent ethics committee of the Greater Region of Eastern Switzerland (EKOS 17/083) approved this study

    Validation of a method to estimate direct normal irradiance of UVA and PAR bands from global horizontal measurements for cloudless sky conditions in Valencia, Spain, by a measurement campaign

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    A method is proposed to provide measurement of direct normal solar irradiance of bands with wavelength ranges (315-400 nm, 400-700 nm) from measurements of global horizontal band irradiance for cloudless sky conditions in Valencia. Global and normal direct irradiance data for every air mass were obtained by applying the SMART2 model to the atmosphere of Valencia. The direct normal to global irradiance ratio was parameterized versus the relative optical air mass. A measurement campaign of global horizontal and diffuse irradiance of UVA and PAR bands was carried out in Valencia, after which, the inferred direct normal irradiance was compared with those provided by the method. The result of the comparison shows that the method is acceptably accurate. The proposed model tends to underestimate the direct normal irradiance of the UVA band by 6%, although for values below 25 W/m2 the model overestimates the direct irradiance by 6%, while for values above 25 W/m2 the model underestimates it by 10%. The other two error estimators used ranging from 11% to 15% are similar in the defined interval measurements in relation to the whole UVA band. Regarding the PAR band, the model overestimates the direct normal irradiance of the PAR band by only 2.2%. With this, the results of the PAR band are more conclusive, as it has been found that for direct normal irradiance values higher than 280 W/m2 the MBE error is almost zero and the other two estimator errors are small, about 5%. © 2010 Springer-Verlag.This work was supported by the Spanish Government through MEC grant MAT2009-14625-C03-03, and is a part of the activities of the Grup d'Optoelectronica i Semiconductors of the Polytechnic University of Valencia. The translation of this paper was funded by the Universidad Politecnica de Valencia, Spain.Serrano Jareño, MA.; Boscá Berga, JV. (2011). Validation of a method to estimate direct normal irradiance of UVA and PAR bands from global horizontal measurements for cloudless sky conditions in Valencia, Spain, by a measurement campaign. Theoretical and Applied Climatology. 103(1):95-101. https://doi.org/10.1007/s00704-010-0284-9S951011031Barth J, Cadet J, Césarini JP, Fitzpatrick TB, McKinlay A, Mutzhas M, Pathak M, Peak M, Sliney D, Urbach F (1999) TC 6-26 report: Standardization of the terms UV-A1, UV-A2 and UV-B, CIE 134-1999 ISBN 3-900-734-94-1Batlles FJ, Olmo FJ, Alados-Arboledas L (1995) On shadowband correction methods for diffuse irradiance measurements. Solar Energy 54(5):105–114Drummond AJ (1956) On the measurement of sky radiation. Arch 602 Meteor Geophys Bioklim B 7:413–436Gueymard C (1995) SMARTS2: a simple model of the atmospheric radiative transfer of sunshine: algorithms and performance assessment. FSEC-PF-270-95, Florida Solar Energy CenterGueymard C (2003) SMARTS2 code, versión 2.9.2. User’s Manual, Solar Consulting Services Bailey CO. Available from http://rredc.nrel.gov/solar/models/SMARTS/smarts_index.htmlGueymard C (2004) The sun’s total and spectral irradiance for solar energy applications and solar radiation models. Solar Energy 76:423–453Häder DP, Lebert M, Marangoni R, Colombetti G (1999) ELDONET-European light dosimeter network hardware and software. J Photochem Photobiol B: Biol 52:51–58Häder DP, Lebert M, Colombetti G, Figueroa F (2001) European light dosimeter network (ELDONET). Helgol Mar Res 55:35–44Iqbal M (1983) An introduction to solar radiation. Academic, TorontoKudish AI, Evseev EG (2008) The assessment of four different correction models applied to the diffuse radiation measured with a shadow ring using global and normal beam radiation measurements for Beer Sheva, Israel. Solar Energy 82(2):144–156LeBaron BA, Michalsky JJ, Perez R (1990) A simple procedure for correcting shadowband data for all sky conditions. Solar Energy 44:249–256Marín Fernández MJ (2007) Estudio de la irradiancia solar ultravioleta y eritemática en la Comunidad Valenciana. Doctoral Thesis University of Valencia (Spain)Perez R, Ineichen P, Seals R, Michalsky JJ, Stewart R (1990) Modelling daylight availability and irradiance components from direct and global irradiance. Sol Energy 44:271–289Pinazo JM, Cañada J, Bosca JV (1995) A new method to determine Ångström's turbidity coefficient: its application for Valencia. Solar Energy 54:219–226Serrano MA, Boscá JV, Cañada J (2008) The determination of a band factor to express irradiance of UV and PAR wavelength ranges in a clean and dry atmosphere at Valencia (Spain). Int J Ambient Energy 29(4):171–180Utrillas MP, Boscà JV, Martinez-Lozano JA, Cañada J, Tena F, Pinazo JM (1998) A comparative study of Spectral2, and Smarts2 parameterised models based on spectral irradiance measurements at Valencia, Spain. Solar Energy 63:161–171Utrillas MP, Marín MJ, Esteve AR, Tena F, Cañada J, Estellés V, Martínez Lozano JA (2007) Diffuse UV erythemal radiation experimental values. J Geophy Res 112:387–39

    Climatic and Biogeochemical Effects of a Galactic Gamma-Ray Burst

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    It is likely that one or more gamma-ray bursts within our galaxy have strongly irradiated the Earth in the last Gy. This produces significant atmospheric ionization and dissociation, resulting in ozone depletion and DNA-damaging ultraviolet solar flux reaching the surface for up to a decade. Here we show the first detailed computation of two other significant effects. Visible opacity of NO2 is sufficient to reduce solar energy at the surface up to a few percent, with the greatest effect at the poles, which may be sufficient to initiate glaciation. Rainout of dilute nitric acid is could have been important for a burst nearer than our conservative nearest burst. These results support the hypothesis that the characteristics of the late Ordovician mass extinction are consistent with GRB initiation.Comment: 12 pages, 2 figures, in press at Geophysical Research Letters. Minor revisions, including details on falsifying the hypothesi

    Evolution of phototaxis

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    Phototaxis in the broadest sense means positive or negative displacement along a light gradient or vector. Prokaryotes most often use a biased random walk strategy, employing type I sensory rhodopsin photoreceptors and two-component signalling to regulate flagellar reversal. This strategy only allows phototaxis along steep light gradients, as found in microbial mats or sediments. Some filamentous cyanobacteria evolved the ability to steer towards a light vector. Even these cyanobacteria, however, can only navigate in two dimensions, gliding on a surface. In contrast, eukaryotes evolved the capacity to follow a light vector in three dimensions in open water. This strategy requires a polarized organism with a stable form, helical swimming with cilia and a shading or focusing body adjacent to a light sensor to allow for discrimination of light direction. Such arrangement and the ability of three-dimensional phototactic navigation evolved at least eight times independently in eukaryotes. The origin of three-dimensional phototaxis often followed a transition from a benthic to a pelagic lifestyle and the acquisition of chloroplasts either via primary or secondary endosymbiosis. Based on our understanding of the mechanism of phototaxis in single-celled eukaryotes and animal larvae, it is possible to define a series of elementary evolutionary steps, each of potential selective advantage, which can lead to pelagic phototactic navigation. We can conclude that it is relatively easy to evolve phototaxis once cell polarity, ciliary swimming and a stable cell shape are present

    Ultraviolet radiation and cyanobacteria.

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    Cyanobacteria are the dominant photosynthetic prokaryotes from an ecological, economical, or evolutionary perspective, and depend on solar energy to conduct their normal life processes. However, the marked increase in solar ultraviolet radiation (UVR) caused by the continuous depletion of the stratospheric ozone shield has fueled serious concerns about the ecological consequences for all living organisms, including cyanobacteria. UV-B radiation can damage cellular DNA and several physiological and biochemical processes in cyanobacterial cells, either directly, through its interaction with certain biomolecules that absorb in the UV range, or indirectly, with the oxidative stress exerted by reactive oxygen species. However, cyanobacteria have a long history of survival on Earth, and they predate the existence of the present ozone shield. To withstand the detrimental effects of solar UVR, these prokaryotes have evolved several lines of defense and various tolerance mechanisms, including avoidance, antioxidant production, DNA repair, protein resynthesis, programmed cell death, and the synthesis of UV-absorbing/screening compounds, such as mycosporine-like amino acids (MAAs) and scytonemin. This study critically reviews the current information on the effects of UVR on several physiological and biochemical processes of cyanobacteria and the various tolerance mechanisms they have developed. Genomic insights into the biosynthesis of MAAs and scytonemin and recent advances in our understanding of the roles of exopolysaccharides and heat shock proteins in photoprotection are also discussed

    Analyses and localization of pectin-like carbohydrates in cell wall and mucilage of the green alga Netrium digitus

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    The unicellular, simply shaped desmid Netrium digitus inhabiting acid bog ponds grows in two phases. Prior to division, the cell elongates at its central zone, whereas in a second phase, polar tip growth occurs. Electron microscopy demonstrates that Netrium is surrounded by a morphologically homogeneous cell wall, which lacks pores. Immunocytochemical and biochemical analyses give insight into physical wall properties and, thus, into adaptation to the extreme environment. The monoclonal antibodies JIM5 and JIM7 directed against pectic epitopes with different degrees of esterification label preferentially growing wall zones in Netrium. In contrast, 2F4 marks the cell wall only after experimental de-esterification. Electron energy loss spectroscopy reveals Ca-binding capacities of pectins and gives indirect evidence for the degree of their esterification. An antibody raised against Netrium mucilage is not only specific to mucilage but also recognizes wall components in transmission electron microscopy and dot blots. These results indicate a smooth transition between mucilage and the cell wall in Netrium

    Ultraviolet radiation shapes seaweed communities

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