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1
Mikuska, P., A. Even, A. Khlystov, H. M. ten Brink, G. P. Wyers, and J. Slanina. "Artefact-free method for size-resolved chemical analysis of ambient aerosols." Journal of Aerosol Science 28 (September 1997): S443—S444. http://dx.doi.org/10.1016/s0021-8502(97)85221-4.
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Elvira, Juan. "Embraced by swirls of ether. Atmospheric imagination and the representation of assimilation and effect." SHS Web of Conferences 64 (2019): 01018. http://dx.doi.org/10.1051/shsconf/20196401018.
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Atmospheres have a diffuse, ungraspable nature that make them problematic to represent. Diverse artistic manifestations have relentlessly tried to grasp air infused with properties. Ether is the concept chosen to test the way the history of atmospheric representation was initiated; a cultural artefact whose representation permeates our present imaginary. Such substance has been the image of sensual assimilation, of psychological life and complex ambient effects. Before ambient was subject to technical representation, images of air within can be called ‘a state of animation’ opened up the ways of seeing and producing ambients. Several case studies are analysed as a useful vehicle for atmospheric representation. Two main strategies have been identified. The first one is the representation of chance, ambiguity and openness, the creation of conditions to let atmospheres leave its accidental traces. The second consists in the precise distribution in space of particles or discrete elements whose initial position is irritated by diverse agents. Both are still recognisable in our days.
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Firoz Khan, Md, Mazrura Sahani, Mohd Shahrul Mohd Nadzir, Lin Chin Yik, Hossain Mohammad Syedul Hoque, Haris Hafizal Abd Hamid, Muhammad Ikram A. Wahab, et al. "Volatile Organic Compound Analysis by Sorbent Tube-Thermal Desorption-Gas Chromatography: A Review." International Journal of Engineering & Technology 7, no. 3.14 (July 25, 2018): 165. http://dx.doi.org/10.14419/ijet.v7i3.14.16878.
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Volatile organic compounds (VOCs) play an important role in the generation of ground level ozone and secondary organic aerosol. Most tropical countries such as Malaysia, Singapore, Indonesia, Brunei experience high ozone pollution. Beside ozone, oxides of nitrogen (NOx) from vehicular emissions also play an important role in photochemical pollution. NOx, particularly nitric oxide (NO), helps to ‘clean up’ ozone concentrations close to traffic in the ambient air of urban areas. Thus, knowledge of the chemistry of ozone-VOCs-NOx and finding the sources of VOCs are crucial to proceed with an appropriate mitigation strategy. Thus, the detection of ozone precursors and related VOCs is thoroughly discussed. This review finds that the inertness, hydrophobicity, and the effect of the artefact materials are very significant factors to be explored in the selection of the sorbent materials. In the SEA region, relative humidity is relatively high and exceeds 90% during the northeast monsoon. Thus, the hydrophobic properties of the sampling material need careful consideration. Further to the effect of relative humidity (RH), the artefact effect of the material itself is a challenge to be optimized and multi-sorbent material in a single tube could be a viable choice to minimize the effect of the unwanted signal in the spectrum.
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Liu, Y., M. Sklorz, J. Schnelle-Kreis, J. Orasche, T. Ferge, A. Kettrup, and R. Zimmermann. "Oxidant denuder sampling for analysis of polycyclic aromatic hydrocarbons and their oxygenated derivates in ambient aerosol: Evaluation of sampling artefact." Chemosphere 62, no. 11 (March 2006): 1889–98. http://dx.doi.org/10.1016/j.chemosphere.2005.07.049.
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Crilley, Leigh R., Marvin Shaw, Ryan Pound, Louisa J. Kramer, Robin Price, Stuart Young, Alastair C. Lewis, and Francis D. Pope. "Evaluation of a low-cost optical particle counter (Alphasense OPC-N2) for ambient air monitoring." Atmospheric Measurement Techniques 11, no. 2 (February 7, 2018): 709–20. http://dx.doi.org/10.5194/amt-11-709-2018.
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Abstract. A fast-growing area of research is the development of low-cost sensors for measuring air pollutants. The affordability and size of low-cost particle sensors makes them an attractive option for use in experiments requiring a number of instruments such as high-density spatial mapping. However, for these low-cost sensors to be useful for these types of studies their accuracy and precision need to be quantified. We evaluated the Alphasense OPC-N2, a promising low-cost miniature optical particle counter, for monitoring ambient airborne particles at typical urban background sites in the UK. The precision of the OPC-N2 was assessed by co-locating 14 instruments at a site to investigate the variation in measured concentrations. Comparison to two different reference optical particle counters as well as a TEOM-FDMS enabled the accuracy of the OPC-N2 to be evaluated. Comparison of the OPC-N2 to the reference optical instruments shows some limitations for measuring mass concentrations of PM1, PM2.5 and PM10. The OPC-N2 demonstrated a significant positive artefact in measured particle mass during times of high ambient RH (> 85 %) and a calibration factor was developed based upon κ-Köhler theory, using average bulk particle aerosol hygroscopicity. Application of this RH correction factor resulted in the OPC-N2 measurements being within 33 % of the TEOM-FDMS, comparable to the agreement between a reference optical particle counter and the TEOM-FDMS (20 %). Inter-unit precision for the 14 OPC-N2 sensors of 22 ± 13 % for PM10 mass concentrations was observed. Overall, the OPC-N2 was found to accurately measure ambient airborne particle mass concentration provided they are (i) correctly calibrated and (ii) corrected for ambient RH. The level of precision demonstrated between multiple OPC-N2s suggests that they would be suitable devices for applications where the spatial variability in particle concentration was to be determined.
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Yttri, K. E., D. Simpson, K. Stenström, H. Puxbaum, and T. Svendby. "Source apportionment of the carbonaceous aerosol in Norway – quantitative estimates based on <sup>14</sup>C, thermal-optical and organic tracer analysis." Atmospheric Chemistry and Physics Discussions 11, no. 3 (March 3, 2011): 7375–422. http://dx.doi.org/10.5194/acpd-11-7375-2011.
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Abstract. In the present study, source apportionment of the ambient summer and winter time particulate carbonaceous matter (PCM) in aerosol particles (PM1 and PM10) has been conducted for the Norwegian urban and rural background environment. Statistical treatment of data from thermal-optical, 14C and organic tracer analysis using Latin Hypercube Sampling has allowed for quantitative estimates of seven different sources contributing to the ambient carbonaceous aerosol. These are: elemental carbon from combustion of biomass (ECbb) and fossil fuel (ECff), organic carbon from combustion of biomass (OCbb), fossil fuel (OCff), primary biological aerosol particles (OCPBAP, which includes plant debris, OCpbc, and fungal spores, OCpbs), and secondary organic aerosol from biogenic precursors (OCBSOA). Our results show that emissions from natural sources were particularly abundant in summer, and with a more pronounced influence at the rural compared to the urban background site. 80% of total carbon (TCp, corrected for the positive artefact) in PM10 and 70% of TCp in PM1 could be attributed to natural sources at the rural background site in summer. Natural sources account for about 50% of TCp in PM10 at the urban background site as well. The natural source contribution was always dominated by OCBSOA, regardless of season, site and size fraction. During winter anthropogenic sources totally dominated the carbonaceous aerosol (83–90%). Combustion of biomass contributed slightly more than fossil-fuel sources in winter, whereas emissions from fossil-fuel sources were more abundant in summer. Mass closure calculations show that PCM likely dominated the mass concentration of the ambient PM regardless of size fraction, season, and site. A larger fraction of PM1 (64–69%) was accounted for by carbonaceous matter compared to PM10 (51–67%), but only by a small margin. In general, there were no pronounced differences in the relative contribution of carbonaceous matter to PM with respect to season or between the two sites.
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Yttri, K. E., D. Simpson, K. Stenström, H. Puxbaum, and T. Svendby. "Source apportionment of the carbonaceous aerosol in Norway – quantitative estimates based on <sup>14</sup>C, thermal-optical and organic tracer analysis." Atmospheric Chemistry and Physics 11, no. 17 (September 9, 2011): 9375–94. http://dx.doi.org/10.5194/acp-11-9375-2011.
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Abstract. In the present study, source apportionment of the ambient summer and winter time particulate carbonaceous matter (PCM) in aerosol particles (PM1 and PM10) has been conducted for the Norwegian urban and rural background environment. Statistical treatment of data from thermal-optical, 14C and organic tracer analysis using Latin Hypercube Sampling has allowed for quantitative estimates of seven different sources contributing to the ambient carbonaceous aerosol. These are: elemental carbon from combustion of biomass (ECbb) and fossil fuel (ECff), primary and secondary organic carbon arising from combustion of biomass (OCbb) and fossil fuel (OCff), primary biological aerosol particles (OCPBAP, which includes plant debris, OCpbc, and fungal spores, OCpbs), and secondary organic aerosol from biogenic precursors (OCBSOA). Our results show that emissions from natural sources were particularly abundant in summer, and with a more pronounced influence at the rural compared to the urban background site. 80% of total carbon (TCp, corrected for the positive artefact) in PM10 and ca. 70% of TCpin PM1 could be attributed to natural sources at the rural background site in summer. Natural sources account for about 50% of TCp in PM10 at the urban background site as well. The natural source contribution was always dominated by OCBSOA, regardless of season, site and size fraction. During winter anthropogenic sources totally dominated the carbonaceous aerosol (80–90%). Combustion of biomass contributed slightly more than fossil-fuel sources in winter, whereas emissions from fossil-fuel sources were more abundant in summer. Mass closure calculations show that PCM made significant contributions to the mass concentration of the ambient PM regardless of size fraction, season, and site. A larger fraction of PM1 (ca. 40–60%) was accounted for by carbonaceous matter compared to PM10 (ca. 40–50%), but only by a small margin. In general, there were no pronounced differences in the relative contribution of carbonaceous matter to PM with respect to season or between the two sites.
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Yttri, K. E., C. Dye, O. A. Braathen, D. Simpson, and E. Steinnes. "Carbonaceous aerosols at urban influenced sites in Norway." Atmospheric Chemistry and Physics Discussions 8, no. 6 (November 17, 2008): 19487–525. http://dx.doi.org/10.5194/acpd-8-19487-2008.
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Abstract. Little is known regarding levels and source strength of carbonaceous aerosols in Scandinavia. In the present study, ambient aerosol (PM10 and PM2.5) concentrations of elemental carbon (EC), organic carbon (OC), water-insoluble organic carbon (WINSOC), and water-soluble organic carbon (WSOC) are reported for a curbside site, an urban background site, and a suburban site in Norway in order to investigate their spatial and seasonal variations. Aerosol filter samples were collected using tandem filter sampling to correct for the positive sampling artefact introduced by semi volatile OC. Analyses were performed using the thermal optical transmission (TOT) instrument from Sunset Lab Inc., which corrects for charring during analysis. Finally, we estimated the relative contribution of OC from wood burning based on the samples content of levoglucosan. Levels of EC varied by more than one order of magnitude between sites, likely due to the higher impact of vehicular traffic at the curbside and the urban background sites. In winter, the level of particulate organic carbon (OCp) at the suburban site was equal to (for PM10) or even higher (for PM2.5) than the levels observed at the curbside and the urban background sites. This finding was attributed to the impact of residential wood burning at the suburban site in winter, which was confirmed by a high mean concentration of levoglucosan (407 ng m−3). This finding indicates that exposure to primary combustion derived OCp could be equally high in residential areas as in a city center. It is demonstrated that OCp from wood burning (OCwood) accounted for almost all OCp at the suburban site in winter, allowing a new estimate of the ratio TCp/levoglucosan for both PM10 and PM2.5. Particulate carbonaceous material (PCM = Organic matter + Elemental matter) accounted for 46–83% of PM10 at the sites studied when considering the positive artefact of semi volatile OC, thus being the major contributor to PM.
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Gysel, M., J. Crosier, D. O. Topping, J. D. Whitehead, K. N. Bower, M. J. Cubison, P. I. Williams, M. J. Flynn, G. B. McFiggans, and H. Coe. "Closure between measured and modelled particle hygroscopic growth during TORCH2 implies ammonium nitrate artefact in the HTDMA measurements." Atmospheric Chemistry and Physics Discussions 6, no. 6 (December 5, 2006): 12503–48. http://dx.doi.org/10.5194/acpd-6-12503-2006.
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Abstract. Measurements of aerosol properties were made in aged polluted and clean background air masses encountered at the North Norfolk (UK) coastline during the second field campaign of the Tropospheric ORganic CHemistry project (TORCH2) in May 2004. Hygroscopic growth factor (GF) measurements were performed at 90% relative humidity (RH) for D0=27–217 nm particles using a Hygroscopicity Tandem Differential Mobility Analyser (HTDMA), while the aerosol composition was simultaneously measured with an Aerodyne aerosol mass spectrometer (Q-AMS). During the clean background events the aerosol was characterised by little size dependence of properties with generally large GFs and inorganic sulphate being the dominant compound. In aged polluted air masses the particles were dominated by inorganic sulphate and nitrate at larger sizes, whereas organics were the largest fraction in smaller particles, thus explaining the trend of smaller GFs at smaller sizes. Organics do contribute to the hygroscopic growth, particularly at small sizes, but generally the dominant contribution to growth at 90% RH comes from inorganic salts. The ZSR mixing rule was used to predict GFs based on the chemical composition, theoretical GFs of pure inorganic salts and a "bulk" GF of ~1.20 for the organics. Good quantitative closure with HTDMA measurements as a function of both particle size and time was achieved in the absence of nitrate. However, GFs were clearly overpredicted at times when a significant fraction of nitrate was present. After careful considerations we attribute the overprediction to substantial evaporation losses of ammonium nitrate in the HTDMA instrument. If true, this implies that the ZSR predictions based on composition might be more representative of the actual "bulk" behaviour of undisturbed ambient particles than the HTDMA measurements. The simplified model approach using the ZSR rule and a constant organic growth factor made high size and time resolution possible, which has proven to be essential for a valid closure study. The ZSR mixing rule appears to be sufficiently accurate, as the GF predictions are more sensitive to the exact GFs of the inorganic compounds than to the growth factor of the moderately hygroscopic organics. Therefore a more detailed analysis and modelling of the organic fraction at the expense of time and size resolution is not worth the effort for an aged aerosol and discrepancies in either direction might even be cancelled out by averaging.
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Lewis, Alastair C., James D. Lee, Peter M. Edwards, Marvin D. Shaw, Mat J. Evans, Sarah J. Moller, Katie R. Smith, et al. "Evaluating the performance of low cost chemical sensors for air pollution research." Faraday Discussions 189 (2016): 85–103. http://dx.doi.org/10.1039/c5fd00201j.
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Low cost pollution sensors have been widely publicized, in principle offering increased information on the distribution of air pollution and a democratization of air quality measurements to amateur users. We report a laboratory study of commonly-used electrochemical sensors and quantify a number of cross-interferences with other atmospheric chemicals, some of which become significant at typical suburban air pollution concentrations. We highlight that artefact signals from co-sampled pollutants such as CO2 can be greater than the electrochemical sensor signal generated by the measurand. We subsequently tested in ambient air, over a period of three weeks, twenty identical commercial sensor packages alongside standard measurements and report on the degree of agreement between references and sensors. We then explore potential experimental approaches to improve sensor performance, enhancing outputs from qualitative to quantitative, focusing on low cost VOC photoionization sensors. Careful signal handling, for example, was seen to improve limits of detection by one order of magnitude. The quantity, magnitude and complexity of analytical interferences that must be characterised to convert a signal into a quantitative observation, with known uncertainties, make standard individual parameter regression inappropriate. We show that one potential solution to this problem is the application of supervised machine learning approaches such as boosted regression trees and Gaussian processes emulation.
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Douthe, Cyril, Erwin Dreyer, Oliver Brendel, and Charles R. Warren. "Is mesophyll conductance to CO2 in leaves of three Eucalyptus species sensitive to short-term changes of irradiance under ambient as well as low O2?" Functional Plant Biology 39, no. 5 (2012): 435. http://dx.doi.org/10.1071/fp11190.
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Mesophyll conductance to CO2 (g m) limits the diffusion of CO2 to the sites of carboxylation, and may respond rapidly (within minutes) to abiotic factors. Using three Eucalyptus species, we tested the rapid response of g m to irradiance under 21% and 1% O2. We used simultaneous measurements of leaf gas exchange and discrimination against 13CO2 with a tuneable diode laser absorption spectrometer. Measurements under 1% O2 were used to limit uncertainties due to 13C–12C fractionation occurring during photorespiration. Switching irradiance from 600 to 200 µmol m–2 s–1 led to a ≈60% decrease of g m within minutes in all species under both 21% O2 and 1% O2. The g m response to irradiance is unlikely to be a computation artefact since using different values for the parameters of the discrimination model changed the absolute values of g m but did not affect the relative response to irradiance. Simulations showed that possible rapid changes of any parameter were unable to explain the observed variations of g m with irradiance, except for13C–12C fractionation during carboxylation (b), which, in turn, is dependent on the fraction of leaf C assimilated by phospho-enol pyruvate carboxylase (PEPc) (β). g m apparently increased by ≈30% when O2 was switched from 21% to 1% O2. Again, possible changes of β with O2 could explain this apparent g m response to O2. Nevertheless, large irradiance or O2-induced changes in β would be required to fully explain the observed changes in g m, reinforcing the hypothesis that g m is responsive to irradiance and possibly also to O2.
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Schaap, M., R. P. Otjes, and E. P. Weijers. "Illustrating the benefit of using hourly monitoring data on secondary inorganic aerosol and its precursors for model evaluation." Atmospheric Chemistry and Physics Discussions 10, no. 5 (May 10, 2010): 12341–70. http://dx.doi.org/10.5194/acpd-10-12341-2010.
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Abstract. Secondary inorganic aerosol, most notably ammonium nitrate and ammonium sulphate, is an important contributor to ambient particulate mass and provides a means for long range transport of acidifying components. The modelling of the formation and fate of these components is challenging. Especially, the formation of the semi-volatile ammonium nitrate is strongly dependent on ambient conditions and the precursor concentrations. For the first time an hourly artefact free data set from the MARGA instrument is available for the period of a full year (1 August 2007 to 1 August 2008) at Cabauw, the Netherlands. This data set is used to verify the results of the LOTOS-EUROS model. The comparison showed that the model underestimates the SIA levels. Closer inspection revealed that base line values appear well estimated for ammonium and sulphate and that the underestimation predominantly takes place at the peak concentrations. For nitrate the variability towards high concentrations is much better captured, however, a systematic relative underestimation was found. The model is able to reproduce many features of the intra-day variability observed for SIA. Although the model captures the seasonal and average diurnal variation of the SIA components, the modelled variability for the nitrate precursor gas nitric acid is much too large. It was found that the thermodynamic equilibrium module produces a too stable ammonium nitrate in winter and during night time in summer, whereas during the daytime in summer it is too unstable. We recommend to improve the model by verification of the equilibrium module, inclusion of coarse mode nitrate and to address the processes concerning SIA formation combined with a detailed analysis of the data set at hand. The benefit of the hourly data with both particulate and gas phase concentrations is illustrated and a continuation of these measurements may prove to be very useful in future model evaluation and improvement studies. Based on our findings we propose to implement a monitoring strategy using three levels of detail within the Netherlands.
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Schaap, M., R. P. Otjes, and E. P. Weijers. "Illustrating the benefit of using hourly monitoring data on secondary inorganic aerosol and its precursors for model evaluation." Atmospheric Chemistry and Physics 11, no. 21 (November 8, 2011): 11041–53. http://dx.doi.org/10.5194/acp-11-11041-2011.
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Abstract. Secondary inorganic aerosol, most notably ammonium nitrate and ammonium sulphate, is an important contributor to ambient particulate mass and provides a means for long range transport of acidifying components. The modelling of the formation and fate of these components is challenging. Especially, the formation of the semi-volatile ammonium nitrate is strongly dependent on ambient conditions and the precursor concentrations. For the first time an hourly artefact free data set from the MARGA instrument is available for the period of a full year (1 August 2007 to 1 August 2008) at Cabauw, the Netherlands. This data set is used to verify the results of the LOTOS-EUROS model. The comparison showed that the model underestimates the SIA levels. Closer inspection revealed that base line values appear well estimated for ammonium and sulphate and that the underestimation predominantly takes place at the peak concentrations. For nitrate the variability towards high concentrations is much better captured, however, a systematic relative underestimation was found. The model is able to reproduce many features of the intra-day variability observed for SIA. Although the model captures the seasonal and average diurnal variation of the SIA components, the modelled variability for the nitrate precursor gas nitric acid is much too large. It was found that the thermodynamic equilibrium module produces a too stable ammonium nitrate in winter and during night time in summer, whereas during the daytime in summer it is too unstable. We recommend to improve the model by verification of the equilibrium module, inclusion of coarse mode nitrate and to address the processes concerning SIA formation combined with a detailed analysis of the data set at hand. The benefit of the hourly data with both particulate and gas phase concentrations is illustrated and a continuation of these measurements may prove to be very useful in future model evaluation and improvement studies. Based on our findings we propose to implement a monitoring strategy using three levels of detail within the Netherlands.
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Yttri, K. E., C. Dye, O. A. Braathen, D. Simpson, and E. Steinnes. "Carbonaceous aerosols in Norwegian urban areas." Atmospheric Chemistry and Physics 9, no. 6 (March 20, 2009): 2007–20. http://dx.doi.org/10.5194/acp-9-2007-2009.
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Abstract. Little is known regarding levels and source strength of carbonaceous aerosols in Scandinavia. In the present study, ambient aerosol (PM10 and PM2.5) concentrations of elemental carbon (EC), organic carbon (OC), water-insoluble organic carbon (WINSOC), and water-soluble organic carbon (WSOC) are reported for a curbside site, an urban background site, and a suburban site in Norway in order to investigate their spatial and seasonal variations. Aerosol filter samples were collected using tandem filter sampling to correct for the positive sampling artefact introduced by volatile and semivolatile OC. Analyses were performed using the thermal optical transmission (TOT) instrument from Sunset Lab Inc., which corrects for charring during analysis. Finally, we estimated the relative contribution of OC from wood burning based on the samples content of levoglucosan. Levels of EC varied by more than one order of magnitude between sites, likely due to the higher impact of vehicular traffic at the curbside and the urban background sites. In winter, the level of particulate organic carbon (OCp) at the suburban site was equal to (for PM10) or even higher (for PM2.5) than the levels observed at the curbside and the urban background sites. This finding was attributed to the impact of residential wood burning at the suburban site in winter, which was confirmed by a high mean concentration of levoglucosan (407 ng m−3). This finding indicates that exposure to primary combustion derived OCp could be equally high in residential areas as in a city center. It is demonstrated that OCp from wood burning (OCwood) accounted for almost all OCp at the suburban site in winter, allowing a new estimate of the ratio TCp/levoglucosan for both PM10 and PM2.5. Particulate carbonaceous material (PCM=Organic matter+Elemental matter) accounted for 46–83% of PM10 at the sites studied, thus being the major fraction.
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Retailleau, Lise, and Gregory C. Beroza. "Towards structural imaging using seismic ambient field correlation artefacts." Geophysical Journal International 225, no. 2 (January 25, 2021): 1453–65. http://dx.doi.org/10.1093/gji/ggab038.
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SUMMARY Correlations of the ambient seismic field recorded by seismic stations carry information about the wave propagation between the stations. They also contain information about the ambient field—both the source of the ambient field, and sources of scattering that contribute to it. The waves that comprise the ambient field are subject to scattering due to the heterogeneous Earth, which can generate supplementary arrivals on the correlation functions. We use these effects to locate sources of signals linked to scattering. For this analysis, we use correlation functions computed from continuous signals recorded between 2013 and 2015 by a line of seismic stations in Central California. We identify spurious arrivals on the Vertical to Vertical and Transverse to Transverse correlation functions and use array analysis to map the source of scattering, which is linked to strong structural variations in the Coast ranges and at the border of the Great Valley.
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Di Biagio, Claudia, Paola Formenti, Mathieu Cazaunau, Edouard Pangui, Nicolas Marchand, and Jean-François Doussin. "Aethalometer multiple scattering correction <i>C</i><sub>ref</sub> for mineral dust aerosols." Atmospheric Measurement Techniques 10, no. 8 (August 15, 2017): 2923–39. http://dx.doi.org/10.5194/amt-10-2923-2017.
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Abstract. In this study we provide a first estimate of the Aethalometer multiple scattering correction Cref for mineral dust aerosols. Cref is an empirical constant used to correct the aerosol absorption coefficient measurements for the multiple scattering artefact of the Aethalometer; i.e. the filter fibres on which aerosols are deposited scatter light and this is miscounted as absorption. The Cref at 450 and 660 nm was obtained from the direct comparison of Aethalometer data (Magee Sci. AE31) with (i) the absorption coefficient calculated as the difference between the extinction and scattering coefficients measured by a Cavity Attenuated Phase Shift Extinction analyser (CAPS PMex) and a nephelometer respectively at 450 nm and (ii) the absorption coefficient from a MAAP (Multi-Angle Absorption Photometer) at 660 nm. Measurements were performed on seven dust aerosol samples generated in the laboratory by the mechanical shaking of natural parent soils issued from different source regions worldwide. The single scattering albedo (SSA) at 450 and 660 nm and the size distribution of the aerosols were also measured. Cref for mineral dust varies between 1.81 and 2.56 for a SSA of 0.85–0.96 at 450 nm and between 1.75 and 2.28 for a SSA of 0.98–0.99 at 660 nm. The calculated mean for dust is 2.09 (±0.22) at 450 nm and 1.92 (±0.17) at 660 nm. With this new Cref the dust absorption coefficient by the Aethalometer is about 2 % (450 nm) and 11 % (660 nm) higher than that obtained by using Cref = 2.14 at both 450 and 660 nm, as usually assumed in the literature. This difference induces a change of up to 3 % in the dust SSA at 660 nm. The Cref seems to be independent of the fine and coarse particle size fractions, and so the obtained Cref can be applied to dust both close to sources and following transport. Additional experiments performed with pure kaolinite minerals and polluted ambient aerosols indicate Cref of 2.49 (±0.02) and 2.32 (±0.01) at 450 and 660 nm (SSA = 0.96–0.97) for kaolinite, and Cref of 2.32 (±0.36) at 450 nm and 2.32 (±0.35) at 660 nm for pollution aerosols (SSA = 0.62–0.87 at 450 nm and 0.42–0.76 at 660 nm).
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Pradhan, Jaya Bishnu. "Cultural artefacts as a metaphor to communicate mathematical ideas." Revemop 2 (March 4, 2020): e202015. http://dx.doi.org/10.33532/revemop.e202015.
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The cultural artifacts created by the culture of a particular group of people embed sophisticated mathematical ideas and knowledge. The cultural artifacts familiar to students mediate to communicate abstract ideas of mathematics. This paper is intended to explore the mathematical ideas embedded in cultural artifacts and to assess its contribution to the process of teaching and learning of school mathematics. The ethnographic methodology was used to collect the data. Highly sophisticated mathematical ideas were found in the analysis of different cultural artifacts observed in the out-of-school environment. The cultural artifacts familiar to students are the source domain of conceptual metaphor to communicate difficult and abstract concepts of mathematics. Both teachers and students reported that the cultural artefacts and different cultural activities of the group of people help them in teaching and learning of mathematical concepts.Keywords: Conceptual Metaphor. Cultural Artefacts. Ethnography. Ethnomathematics. Mathematical Ideas.Los artefactos culturales como una metáfora para la comunicación de las ideas matemáticasLos artefactos culturales creados por la cultura de un grupo particular de personas incorporan ideas y conocimientos matemáticos sofisticados. Los artefactos culturales familiares para los estudiantes median para comunicar ideas abstractas de las matemáticas. Este documento tiene como objetivo explorar las ideas matemáticas incrustadas en artefactos culturales y evaluar su contribución al proceso de enseñanza y aprendizaje de las matemáticas escolares. La metodología etnográfica se utilizó para recopilar los datos. Se encontraron ideas matemáticas altamente sofisticadas en el análisis de diferentes artefactos culturales observados en el entorno fuera de la escuela. Los artefactos culturales familiares para los estudiantes son el dominio fuente de la metáfora conceptual para comunicar conceptos matemáticos difíciles y abstractos. Tanto maestros como estudiantes informaron que los artefactos culturales y las diferentes actividades culturales del grupo de personas los ayudan a enseñar y aprender conceptos matemáticos.Palabras clave: Metáfora Conceptual. Artefactos Culturales. Etnografía. Etnomatemáticas. Ideas Matemáticas.Artefatos culturais como uma metáfora para comunicação de ideias matemáticasOs artefatos culturais criados pela cultura de um determinado grupo de pessoas incorporam ideias e conhecimentos matemáticos sofisticados. Os artefatos culturais familiares aos alunos auxiliam na mediação para comunicar ideias abstratas da Matemática. Este artigo objetiva explorar as ideias matemáticas incorporadas aos artefatos culturais e avaliar sua contribuição para o processo de ensino e aprendizagem da matemática escolar. A metodologia etnográfica foi utilizada para a coleta dos dados. Ideias matemáticas altamente sofisticadas foram encontradas na análise de diferentes artefatos culturais observados no ambiente extra-escolar. Os artefatos culturais familiares aos alunos são o domínio de origem da metáfora conceitual para comunicar conceitos difíceis e abstratos da matemática. Professores e alunos relataram que os artefatos culturais e as diferentes atividades culturais do grupo de pessoas os ajudam a ensinar e aprender conceitos matemáticos.Palavras-chave: Metáfora Conceitual. Artefatos Culturais, Etnografia, Etnomatemática, Ideias Matemáticas.
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Silva, Wagner Rodrigues. "Regulamentação linguística em e-mails institucionais: conflito entre professores universitários no ambiente institucional." Linguagem em (Dis)curso 12, no. 1 (April 2012): 15–45. http://dx.doi.org/10.1590/s1518-76322012000100002.
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Investigo reflexões metalinguísticas realizadas por docentes, ao focalizarem noções de ordem ou de regulamentação linguística, no ambiente de interação virtual, mediado por um programa de e-mail institucional, numa universidade pública. Numa abordagem sociopragmática, o ambiente virtual é caracterizado como um tecido de vozes sociais, as quais sinalizam para o posicionamento dos interactantes no espaço institucional em que estão inseridos. Os dados mostram servidores públicos se apropriando de um artefato tecnológico para interagir num novo espaço: o ambiente profissional virtual. A troca de mensagens eletrônicas parece influenciada por outras interações mediadas por artefatos digitais característicos de ambientes virtuais não profissionais. Nesse novo ambiente, tais interações parecem substituir os relacionamentos profissionais sólidos, característicos das interações presenciais, minimizando o receio do enfoque de assuntos polêmicos para interlocuções convencionais, como o questionamento da competência profissional dos pares, orientado pela cobrança das convenções linguísticas da escrita formal, em mensagens eletrônicas trocadas no ambiente virtual institucional.
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Varona, Erika TM, Carlos AA Páez, and Alejandro B. Moreno. "Artefactos Explosivos Improvisados, Atención En Ambientes Austeros." Panamerican Journal of Trauma, Critical Care & Emergency Surgery 6, no. 2 (2017): 61–67. http://dx.doi.org/10.5005/jp-journals-10030-1174.
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RESUMEN Introducción El trauma de guerra no convencional aún no está plenamente estudiado, se busca identificar tipos de lesiones en pacientes heridos por artefactos explosivos improvisados (AEI), en Colombia entre febrero de 2004 y mayo de 2014 que fueron atendidos por una de las unidades de atención quirúrgica móvil del ejército nacional de Colombia en ambiente austero (selva), con recursos limitados y remitidos posteriormente a hospital de cuarto nivel para manejo definitivo. Materiales y métodos Estudio observacional, descriptivo basado en una cohorte histórica. Se analizó la base de datos de pacientes civiles y soldados de las fuerzas militares de colombia que recibieron atención por los Grupos Avanzados de Trauma en ambientes austeros cercanos a las áreas de guerra, por artefacto explosivo. Se realizó revisión manual de las historias clínicas registrando las lesiones presentadas por pacientes al ingreso a la institución de salud de cuarto nivel. Se hace análisis con tablas dinámicas, frecuencias, tendencias, modas de los datos y se hace análisis de los mismos. Criterios de inclusión Pacientes que se encuentran registrados en base la de datos realizada por médicos participantes del grupo avanzado de trauma entre los años de 2004 al 2014 y que fueron víctimas por armas de fragmentación no convencionales. Resultados Se evaluó un total de 182 pacientes, Con promedio de edad de 23 años; Hubo 158 lesiones ortopédicas, la amputación fue la más frecuente en 105 pacientes (66.4%), de las cuales 64.2% fueron infracondileas, 1.64 % de miembros superiores y 0.54% supracondileas. Y según rango militar; soldados 81.4% y Oficiales 6%. Asociado al trauma oseo se presentó otras complicaciones como; Embolismo graso 1.64%, Osteomielitis 2.94% Trauma acústico 3.85%, Trauma ocular 3.29%, Trauma facial 7.14%, Trauma cráneo encefálico 0.54%, Neuropatías 4.94%, Sepsis por K. Pneumonia y E. Faecalis 2.19%, con una mortalidad global de 1 paciente (0,58%) Conclusión En Colombia entre febrero de 2004 y Mayo del 2014 los AEI fueron la causa más frecuente de heridos de guerra generando lesiones osteomusculares con predominio de amputaciones infracondileas, con baja incidencia infecciones asociadas y mortalidad asociada. How to cite this article Varona ETM, Páez CAA, Moreno AB. Artefactos Explosivos Improvisados, Atención En Ambientes Austeros. Panam J Trauma Crit Care Emerg Surg 2017;6(2):61-67.
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Sosa, Milton Eduardo, and Eduardo Omar Sosa. "Internet de las Cosas en Entornos Académicos. Caso de Éxito en la Universidad de Misiones." Elektron 1, no. 1 (July 11, 2017): 23–28. http://dx.doi.org/10.37537/rev.elektron.1.1.9.2017.
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Actualmente, los equipos y artefactos destinados a la iluminación, ventilación y acondicionamiento del aire, en los ambientes de la Universidad de Misiones, se controlan de forma completamente manual. Se ha comprobado que dichos equipos y artefactos permanecen conectados inclusive en ausencia de alumnos y docentes, no existiendo a la fecha control y actuación alguna sobre la temperatura ambiente y/o iluminación. El presente trabajo introduce el desarrollo inicial de un sistema de control automatizado inteligente de equipos y aparatos, morigerando así costos y aportes al efecto invernadero. La solución planteada se lleva a cabo con ayuda de componentes económicos y usufructuando la infraestructura física existente en la dependencia. El sistema realiza el monitoreo, control de luminarias y de los equipos de acondicionamiento de aire, así como también, la presencia de personas en los ambientes. La central permite el accionamiento y control de los módulos en forma remota por medio de una aplicación desarrollada al efecto.
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Xi, Chaoqiang, Jianghai Xia, Binbin Mi, Tianyu Dai, Ya Liu, and Ling Ning. "Modified frequency–Bessel transform method for dispersion imaging of Rayleigh waves from ambient seismic noise." Geophysical Journal International 225, no. 2 (January 11, 2021): 1271–80. http://dx.doi.org/10.1093/gji/ggab008.
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SUMMARY Ambient noise surface wave methods have gained much attention among geophysical and civil engineering communities because of their capability of determining near-surface shear wave velocities in highly populated urban areas. Higher mode information of surface waves is important in dispersion curve inversion for shear wave velocity structure. The frequency–Bessel (F-J) transform method is an effective tool for multimode surface wave extraction, which has been applied to multiscale investigations of the Earth structure. The measured dispersion energy with the F-J method, however, would usually be contaminated by a type of ‘crossed’ artefacts at high frequencies, which are caused by spatial aliasing and bidirectional velocity scan of dispersion analysis methods. The ‘crossed’ artefacts usually cross and smear the true dispersion energy in the frequency–velocity domain. We propose a modified F-J (MFJ) transform method in which the Bessel function is replaced by the Hankel function for dispersion analysis of empirical Green's function. The MFJ method performs a unidirectional velocity scanning on the outgoing wave to avoid the ‘crossed’ artefacts. Synthetic and real-world examples demonstrate the effectiveness of the proposed MFJ method in improving the accuracy of Rayleigh wave multimode dispersion measurements.
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Rodrigues, Maria das Dôres Farias, and Karla Rosane do Amaral Demoly. "O jogo de areia como ferramenta na Educação Ambiental." Revista Brasileira de Educação Ambiental (RevBEA) 9, no. 2 (December 27, 2014): 395–411. http://dx.doi.org/10.34024/revbea.2014.v9.1839.
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Este artigo discute experiências de formação em educação ambiental desenvolvidas no emprego do artefato técnico designado como o jogo de areia em uma escola pública estadual de Mossoró-RN. A rede teórica de sustentação da análise encontramos desde a inverção da ferramenta jogo de areia com os trabalhos de Dora Marai Kalf, Margareth Lowenfeldt, dentro outros que trazem o enfoque da Psicologia Clínica. Temos a relação ainda recente do jogo de areia na educação escolar e nosso estudo participa desta construção embasada nas teorias da Biologia da Cognição de Humberto Maturana em diálogo com outros pesquisadores. A vivência que o jogo de areia oportuniza para estudantes indicam que esta tecnologia favorece o conhecimento nos processos que configuram o aprender a cuidar de si e do meio ambiente também a partir da escola.
Palavras-chave: Jogo de areia, tecnologia, educação ambiental, transformação
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Do Amaral, Alessandra Meireles, Ana Regina Dalmaschio Carrijo, Ana Nery Furlan Mendes, and Sandra Mara Santana Rocha. "DESSALINIZADOR SOLAR PORTÁTIL: UM ARTEFATO TRANSDISCIPLINAR." Revista Conhecimento Online 1 (January 1, 2018): 88. http://dx.doi.org/10.25112/rco.v1i0.514.
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O dessalinizador solar portátil é um artefato de ensino transdisciplinar que proporciona uma abordagem diferenciada de temas atuais e relevantes, podendo contribuir de forma significativa com o processo de aprendizagem escolar e o desenvolvimento do aluno como cidadão, conforme as exigências atuais do Ensino Médio. A sua produção e a utilização tem por objetivo a sensibilização dos alunos a respeito da problemática de escassez da água, propondo um método alternativo e de baixo custo que visa à purificação da água salgada, movido à energia solar. Dentro das abordagens curriculares deste artefato, podem-se levantar questões pertinentes às transformações dos estados físicos da matéria e separação de substâncias de uma solução, associadas ao ciclo da água e, ainda, destacar a importância da reutilização de materiais para reduzir a quantidade de lixo lançado no ambiente. Por se tratar de um objeto que contempla a temática da educação ambiental, o dessalinizador pode ser aplicado em todas as séries do Ensino Médio, dentro da área de Ciências Naturais, nas disciplinas de Biologia, Química e Física, englobando os aspectos que melhor se adequam aos conteúdos trabalhados.Palavras-chave: Artefato de Ensino. Ensino de Química. Transdisciplinaridade. ABSTRACTThe portable solar desalinator is a transdisciplinary teaching device that provides a differentiated approach to those current and relevant topics and can contribute significantly to the process of school learning and the development of the student as a citizen, as the current requirements of High School. Its production and use aims at raising awareness among students about the problem of water scarcity, proposing an alternative and cost of salt water purification method, working as pure solar-powered. Within the curricular approaches of this artifact, pertinent questions can be raised about the transformation of state of matter and separating substances in a solution associated with the water cycle, and also highlight the importance of reusing materials to reduce the amount of dump released into the environment. Because it is a guided object for the theme of environmental education, the desalinator can be applied to all High School grades, within the area of Natural Sciences in Biology disciplines, Chemistry and Physics, covering the aspects that best suit worked contents.Keywords: Teaching Artifact. Chemistry Education. Transdisciplinary.
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López Hernández, Eduardo S., Ana Rosa Rodríguez Luna, and Carlos David López Ricalde. "Gestión sustentable de pilas e intervenciones educativas para mitigar sus efectos en la salud humana y el ambiente." HORIZONTE SANITARIO 10, no. 2 (August 19, 2014): 29. http://dx.doi.org/10.19136/hs.a10n2.123.
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El trabajo se realizó dentro del Programa Ambiental para el Desarrollo Sustentable de la Universidad Juárez Autónoma de Tabasco (López-Hernández y Priego, 2007), para planear alternativas sobre residuos sólidos altamente contaminantes como las pilas (dispositivo pequeño en el que la energía química se transforma en eléctrica. Tiene múltiples aplicaciones como fuente de energía en pequeños aparatos. (RAE, 2011). El manejo incorrecto de estos residuos es un problema socio-ambiental con efectos mundiales. Se requieren nuevos enfoques en el manejo para la disposición final al término de su vida útil. Por lo anterior, se plantea contribuir a resolver la problemática relacionada con su alto consumo, extendida por la facilidad de utilizarlas en diversos artefactos. Una vez convertidas en basura generan residuos tóxicos como Zn, Li, Ni, Cd, Ag y Hg. (Castro Díaz, 2003). Así, se persiguió elaborar una propuesta educativa para el manejo, gestión y disposición de pilas. Establecer recomendaciones para reducir, y prevenir sustentablemente los efectos que provocan en la salud y el ambiente. A partir de la recopilación bibliográfica sobre tratamientos para estos peligrosos, se hizo una clasificación de tipos, clases y uso de pilas. Se definieron los componentes tóxicos según el Diario Oficial de la Federación (2006). Se investigaron los efectos nocivos al ambiente y la salud. Se diseñaron actividades de educación ambiental basadas con objetivos, técnicas de manejo (generación, separación, transporte, almacenamiento, tratamiento y disposición final). Se plantearon alternativas para una disposición final sustentable como los rellenos sanitarios para residuos de manejo especial y/o peligroso, como las pilas agotadas.
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López Hernández, Eduardo S., Ana Rosa Rodríguez Luna, and Carlos David López Ricalde. "Gestión sustentable de pilas e intervenciones educativas para mitigar sus efectos en la salud humana y el ambiente." HORIZONTE SANITARIO 10, no. 2 (August 19, 2014): 29. http://dx.doi.org/10.19136/hs.v10i2.123.
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El trabajo se realizó dentro del Programa Ambiental para el Desarrollo Sustentable de la Universidad Juárez Autónoma de Tabasco (López-Hernández y Priego, 2007), para planear alternativas sobre residuos sólidos altamente contaminantes como las pilas (dispositivo pequeño en el que la energía química se transforma en eléctrica. Tiene múltiples aplicaciones como fuente de energía en pequeños aparatos. (RAE, 2011). El manejo incorrecto de estos residuos es un problema socio-ambiental con efectos mundiales. Se requieren nuevos enfoques en el manejo para la disposición final al término de su vida útil. Por lo anterior, se plantea contribuir a resolver la problemática relacionada con su alto consumo, extendida por la facilidad de utilizarlas en diversos artefactos. Una vez convertidas en basura generan residuos tóxicos como Zn, Li, Ni, Cd, Ag y Hg. (Castro Díaz, 2003). Así, se persiguió elaborar una propuesta educativa para el manejo, gestión y disposición de pilas. Establecer recomendaciones para reducir, y prevenir sustentablemente los efectos que provocan en la salud y el ambiente. A partir de la recopilación bibliográfica sobre tratamientos para estos peligrosos, se hizo una clasificación de tipos, clases y uso de pilas. Se definieron los componentes tóxicos según el Diario Oficial de la Federación (2006). Se investigaron los efectos nocivos al ambiente y la salud. Se diseñaron actividades de educación ambiental basadas con objetivos, técnicas de manejo (generación, separación, transporte, almacenamiento, tratamiento y disposición final). Se plantearon alternativas para una disposición final sustentable como los rellenos sanitarios para residuos de manejo especial y/o peligroso, como las pilas agotadas.
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Guimarães, Iara Vieira, and Lucélia Bárbara Moraes Hortêncio. "O discurso sobre sustentabilidade e os desafios ambientais na Revista Nova Escola: notas para reflexão." Pesquisa em Educação Ambiental 10, no. 2 (December 18, 2015): 63. http://dx.doi.org/10.18675/2177-580x.vol10.n2.p63-77.
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<p>O texto analisa um artefato cultural criado para promover a informação e a formação de professores da educação básica. Busca-se compreender o modo como a Revista Nova Escola (RNE), publicada pela Editora Abril, apresenta aos educadores diferentes tipos de textos e sentidos sobre a questão da Educação Ambiental no ano de 2012. De maneira mais específica a problemática que orientou a discussão empreendida no presente texto pode ser expressa segundo os seguintes questionamentos: como as questões ambientais são apresentadas na Revista Nova Escola? Que discursos a revista defende sobre meio ambiente? A pesquisa empreendida caracterizou-se como qualitativa com procedimentos próprios da análise documental. Observou-se que o discurso sobre meio ambiente, construído por Nova Escola, está profundamente conectado ao discurso empresarial e à defesa do desenvolvimento sustentável. A publicação divulga como verdadeira a ideia de que o meio ambiente saudável e equilibrado pode coexistir com o modo de produção capitalista. O discurso da sustentabilidade é veementemente defendido pela revista como única alternativa para a resolução dos desafios ambientais. Não há evidências no <em>corpus</em> analisado sobre questionamentos em relação a tal ideia, tampouco a apresentação de toda uma discussão feita atualmente em torno dos limites e problemas do chamado desenvolvimento sustentável.</p>
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Pfeifer, Sascha, Thomas Müller, Andrew Freedman, and Alfred Wiedensohler. "The influence of the baseline drift on the resulting extinction values of a cavity attenuated phase shift-based extinction monitor (CAPS PMex)." Atmospheric Measurement Techniques 13, no. 5 (May 5, 2020): 2161–67. http://dx.doi.org/10.5194/amt-13-2161-2020.
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Abstract. The effect of the baseline drift on the resulting extinction values of three cavity attenuated phase shift-based extinction monitors (CAPS PMex) with different wavelengths and the respective correlation with NO2 was analysed for an urban background station. A drift of more than 0.8 Mm-1min-1 was observed for ambient air, with high probability caused by traffic-emissions-driven changes in carrier gas composition. The baseline drift leads to characteristic measurement artefacts for particle extinction. Artificial particle extinction values of approximately 4 Mm−1 were observed using a baseline period of 5 min. These values can be even higher for longer baseline periods. Two methods are shown to minimize this effect. Modified continuous baseline values are calculated in a post-processing step using simple linear interpolation and cubic smoothing splines. Both methods are useful to reduce artefacts, although the use of cubic smoothing splines gives slightly better results. The extinction artefacts are diminished and the effective scattering of the resulting extinction values is reduced by about 50 %.
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Paschoarelli, Luis Carlos, Guilherme Barbosa dos Santos, and Marco Antônio dos Reis Pereira. "Aplicação de materiais sustentáveis no design de artefatos de uso cotidiano: o caso do cabo de tesoura em bambu laminado." Design e Tecnologia 9, no. 17 (May 5, 2019): 20–29. http://dx.doi.org/10.23972/det2019iss17pp20-29.
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O desenvolvimento de produtos sustentáveis requer a pesquisa e aplicação de novos materiais e processos de baixo impacto ambiental. Alguns componentes utilizados na fabricação de artefatos de uso diário podem causar desequilíbrio ao meio ambiente quando descartados indevidamente, logo, a substituição dos materiais e processos atualmente empregados por outros menos nocivos indica vantagens ambientais e também competitivas. Esses tipos de materiais apontam para novas fontes de matérias-primas, inserem novos setores na cadeia de suprimentos e contribuem para a gestão em logística reversa. Considerando os fatores supracitados e o potencial do bambu, enquanto material alternativo, este trabalho objetiva demonstrar a aplicação do mesmo no desenvolvimento de um artefato de uso diário, a saber, em uma proposta de cabo de tesoura, sob uma abordagem que considera critérios biomecânicos, e sobretudo, aspectos ecológicos.
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Graham, Elizabeth, David M. Pendergast, Jorge Calvera, and Juan Jardines. "Excavations at Los Buchillones, Cuba." Antiquity 74, no. 284 (June 2000): 263–64. http://dx.doi.org/10.1017/s0003598x00059160.
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Between 1989 and 1994, north coast fishermen Nelson Torna and Pedro Guerra salvaged approximately 195 well-preserved wooden artefacts, mostly of lignum vitcre, from recently disturbed marine sediments near their village of Punta Alegre, in Ciego de Avila, Cuba. They had collected the artefacts from a shallow lagoon, and from the shoreline near their village at a place known as Los Buchillones. The wooden artefacts include pins, eyed needles, hooks, fragments of dishes, handles for axes (including two that retained the stone tools), duhos or stools that served as badges of rank in Taino society, and zemis or male deity figures. In 1994, on an official Royal Ontario Museum visit to Cuba, then curator David Pendergast was shown these artefacts, and discussions began between Pendergast and Cuban archaeologists Dr Jorge Calvera and Lic. Juan Jardines concerning the possibility of launching an investigation of the contexts from which the artifacts had come. The Royal Ontario Museum (ROM) thereby established a jointly directed and jointly funded project with the Ministerio de Ciencia, Tecnologia, y Medio Ambiente (CITMA) of the government of Cuba, and investigations began in 1997
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Magalhães, Marcos Pereira. "Território cultural e a transformação da floresta em artefato social." Boletim do Museu Paraense Emílio Goeldi. Ciências Humanas 8, no. 2 (August 2013): 381–400. http://dx.doi.org/10.1590/s1981-81222013000200010.
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Em uma das perspectivas da arqueologia da paisagem, todo território cultural é um espaço cujas paisagens são construídas e os ambientes transformados em artefatos sociais. O espaço de manifestação social de uma cultura apresenta locais com ocorrências materiais e recursos naturais diversos, que compõem um território cultural com diferentes ambientes antropogênicos relacionados. Sendo assim, tal como os objetos materiais, as paisagens reproduzem as representações espirituais, políticas e econômicas de uma sociedade. Estudos arqueológicos realizados na região de Porto Trombetas, estado do Pará, têm verificado a maneira como as sociedades relacionadas ao estilo cerâmico Kondurí alteraram os ambientes, interferindo, criando, semeando ou cultivando espécies selecionadas, segundo as suas particularidades culturais. Inventário botânico e escavações arqueológicas realizadas no sítio Greig II, com cultura material Kondurí, indicam como atividades específicas tornam os ambientes mais produtivos e, simultaneamente, familiares, sendo culturalmente identificáveis. Independentemente das possíveis variações estilísticas encontradas na cultura material, acreditamos que as antigas populações amazônicas construíram paisagens onde elas se organizaram e se identificaram social e territorialmente.
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Martinez, César Augusto Ferrari. "Entrevista com Erik Swyngedouw." Geosul 33, no. 67 (May 22, 2018): 277–87. http://dx.doi.org/10.5007/2177-5230.2018v33n67p277.
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Erik Swyngedouw é um geógrafo e ecologista político belga radicado no Reino Unido, onde é Professor de Geografia Política e Econômica na Escola de Meio Ambiente, Educação e Desenvolvimento da Universidade de Manchester. Com formação ambiental como engenheiro agrônomo e doutorado em geografia crítica, Swyngedouw é um dos autores-chave no entendimento dos usos da natureza como artefato de poder na produção do espaço pela modernidade. Sua obra inclui estudos sobre escala, discursos sobre a natureza, controle de redes hídricas, contextos de pós-democracia – todos pautados por densa análise crítica do processo de globalização. Recentemente, publicou Liquid Power, no qual analisa o papel do controle sobre as redes de água na produção do espaço espanhol pelo governo franquista. Esta entrevista se deu em inglês e pela ocasião da participação do Professor Swyngedouw na Conferência “Knowledge / Culture / Ecologies” em Santiago do Chile no mês de novembro de 2017, sendo traduzida por mim ao Português.
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Michoud, V., R. F. Hansen, N. Locoge, P. S. Stevens, and S. Dusanter. "Detailed characterizations of a Comparative Reactivity Method (CRM) instrument: experiments vs. modelling." Atmospheric Measurement Techniques Discussions 8, no. 4 (April 16, 2015): 3803–50. http://dx.doi.org/10.5194/amtd-8-3803-2015.
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Abstract. The Hydroxyl radical (OH) is an important oxidant in the daytime troposphere that controls the lifetime of most trace gases, whose oxidation leads to the formation of harmful secondary pollutants such as ozone (O3) and Secondary Organic Aerosols (SOA). In spite of the importance of OH, uncertainties remain concerning its atmospheric budget and integrated measurements of the total sink of OH can help reducing these uncertainties. In this context, several methods have been developed to measure the first-order loss rate of ambient OH, called total OH reactivity. Among these techniques, the Comparative Reactivity Method (CRM) is promising and has already been widely used in the field and in atmospheric simulation chambers. This technique relies on monitoring competitive OH reactions between a reference molecule (pyrrole) and compounds present in ambient air inside a sampling reactor. However, artefacts and interferences exist for this method and a thorough characterization of the CRM technique is needed. In this study, we present a detailed characterization of a CRM instrument, assessing the corrections that need to be applied on ambient measurements. The main corrections are, in the order of their integration in the data processing: (1) a correction for a change in relative humidity between zero air and ambient air, (2) a correction for the formation of spurious OH when artificially produced HO2 react with NO in the sampling reactor, and (3) a correction for a deviation from pseudo first-order kinetics. The dependences of these artefacts to various measurable parameters, such as the pyrrole-to-OH ratio or the bimolecular reaction rate constants of ambient trace gases with OH are also studied. From these dependences, parameterizations are proposed to correct the OH reactivity measurements from the abovementioned artefacts. A comparison of experimental and simulation results is then discussed. The simulations were performed using a 0-D box model including either (1) a simple chemical mechanism, taking into account the inorganic chemistry from IUPAC 2001 and a simple organic chemistry scheme including only a generic RO2 compounds for all oxidized organic trace gases; and (2) a more exhaustive chemical mechanism, based on the Master Chemical Mechanism (MCM), including the chemistry of the different trace gases used during laboratory experiments. Both mechanisms take into account self- and cross-reactions of radical species. The simulations using these mechanisms allow reproducing the magnitude of the corrections needed to account for NO interferences and a deviation from pseudo first-order kinetics, as well as their dependence on the Pyrrole-to-OH ratio and on bimolecular reaction rate constants of trace gases. The reasonable agreement found between laboratory experiments and model simulations gives confidence in the parameterizations proposed to correct the Total OH reactivity measured by CRM. However, it must be noted that the parameterizations presented in this paper are suitable for the CRM instrument used during the laboratory characterization and may be not appropriate for other CRM instruments, even if similar behaviours should be observed. It is therefore recommended that each group characterizes its own instrument following the recommendations given in this study. Finally, the assessment of the limit of detection and total uncertainties is discussed and an example of field deployment of this CRM instrument is presented.
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Corber, Andrew, Wajid Chishty, and Patrizio Vena. "Planar LIF/MIE ratio droplet sizing using structured laser sheet imaging at elevated ambient pressures." Journal of the Global Power and Propulsion Society 4 (May 13, 2020): 38–47. http://dx.doi.org/10.33737/jgpps/115249.
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LIF/Mie ratio-metric imaging was used to characterize sprays produced by a simple hollow-cone pressure atomizer, operating under elevated ambient pressures up to 10 atm. A structured laser sheet was used as the source of illumination to suppress the multiple scattered light, generating images that are free of the artefacts typically found in conventional laser sheet images. The resulting LIF/Mie ratio-metric images were calibrated using Phase Doppler anemometry to generate axial planar maps of the spray’s Sauter-mean diameter (SMD). This calibration methodology was applied over a range of ambient pressures and liquid flows to assess the robustness of the structured LIF/Mie ratio-metric imaging as a droplet sizing technique. The test fluids consisted of conventional and alternative jet fuels as well as nozzle calibration fluid. Results presented in the paper indicate both the effectiveness and certain limitations of the technique.
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Yabuki, Maikol Yoshie, Caio Otoni, and Maria Gabriela Caffarena Celani. "Alta tecnologia e reúso de materiais descartados: desenvolvimento de um painel decorativo para a melhoria do desempenho térmico em edificações." Gestão & Tecnologia de Projetos 15, no. 2 (June 29, 2020): 6–19. http://dx.doi.org/10.11606/gtp.v15i2.155158.
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O século XXI expressa um intenso avanço tecnológico aplicado nos mais diversos equipamentos gradualmente mais acessíveis à sociedade. Ao mesmo tempo, para atender a essa demanda, os recursos naturais são consumidos exponencialmente, gerando uma enorme quantidade de resíduos com destinação nem sempre adequada. Os principais agentes ligados à tentativa de redução desse impacto ambiental negativo por meio da reutilização de materiais são as cooperativas de reciclagem, responsáveis pela seleção dos materiais descartados e reintrodução no sistema produtivo. Através da Design Science Research, a pesquisa visa a criação de um artefato utilizando materiais descartados a fim de reintroduzi-los na cadeia produtiva sob a forma de elementos arquitetônicos de acabamento. Pela elevada representação nos materiais descartados, baixo índice de reaproveitamento e potencial de reconformação a quente, no estado fundido, o termoplástico poliestireno foi selecionado como matéria prima para o desenvolvimento de placas de acabamento para o teto (forro). Como maneira de agregar ainda mais valor ao produto, a constituição dos módulos do painel foi realizada a partir de moldes projetados com o uso de modelos paramétricos digitais e produzidos com o uso de impressora 3D. Além disso, o mesmo foi utilizado não apenas como acabamento estético, mas também como sistema de macroencapsulamento para um material de mudança de fase (Phase Change Material), que contribui para o desempenho energético e o conforto térmico no ambiente em que é instalado. A pesquisa, de caráter interdisciplinar, envolveu pesquisadores das áreas de design, arquitetura, ciência dos materiais e conforto ambiental. O protótipo desenvolvido demonstra a possibilidade de se agregar valor a materiais descartados por meio de novas tecnologias de design, fabricação e materiais, e ainda contribui para a redução do gasto de energia, tanto na reciclagem do próprio plástico como na diminuição da temperatura do ambiente, apontando para possíveis desdobramentos de produção por cooperativas.
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Musnaini, Musnaini. "HUBUNGAN KONSTRUK SERVICESCAPE DAN KEPUASAN KONSUMEN COFFE SHOP DI KOTA JAMBI." Competence : Journal of Management Studies 13, no. 1 (February 26, 2020): 34–43. http://dx.doi.org/10.21107/kompetensi.v13i1.6821.
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Tujuan penelit ian ini untuk menjelaskan hubungan antara Servicescape yaitu Ambient Condit ion(X1), Spatial Layout/Funct ion(X2) dan Sign Symbol/Artefac (X3) dan Kepuasan Konsumen Coffee Shop di kota Jambi. Penelit ian ini menggunakan pendekatan eksplanasi. Pengumpulan data dengan kuisoner kepada 100 responden secara Judgmental Sampling. Model penelit ian diolah menggunaka regresi berganda dengan software IBM SPSS Statisctics 25. Hasil analisa membuktikanbahwa secara simultan terdapat hubungan disignifikan antara dimensi Servicescape terhadap kepuasan konsumen Coffee Shop di kota Jambi. Ternyata secara parsial kepuasan konsumen Coffee Shop di jambi dominan dipengaruhi oleh dimensi Spat ial Layout/Funct ion yaitu sebesar 13,54%.
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Monterroza Ríos, Alvaro David, and Jorge Antonio Mejía Escobar. "Artefactos y símbolos como dispositivos causales de la cultura." trilogía Ciencia Tecnología Sociedad 5, no. 8 (June 30, 2013): 39. http://dx.doi.org/10.22430/21457778.285.
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El propósito de este artículo es señalar que entre el conjunto de bienes tangibles e intangibles que constituyen a la cultura humana hay un olvido por parte de las ciencias sociales y las humanidades, de los efectos causales que produce el entorno material y sus artefactos. Se defiende una visión de cultura como arreglos causales en las que no existe diferencia entre cultura material y cultura simbólica, que da como consecuencia la aceptación del entorno artificial como nicho ecológico, en las que existe una coevolución entre el ambiente técnico y los humanos. Esto convierte a las redes de artefactos en el hábitat de los seres humanos en el que son posibles las prácticas humanas.
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Mucci, Daniel Magalhães, Fabio Frezatti, and Mamadou Dieng. "As Múltiplas Funções do Orçamento Empresarial." Revista de Administração Contemporânea 20, no. 3 (June 2016): 283–304. http://dx.doi.org/10.1590/1982-7849rac2016140121.
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Resumo O orçamento é um dos principais artefatos de gestão e é utilizado para diferentes propósitos. Estudos têm desconsiderado que esse artefato pode ser utilizado para múltiplas funções e ser percebido diferentemente por executivos dentro de uma mesma organização. Este artigo discute a ideia de múltiplas funções do orçamento empresarial e investiga sua associação com a percepção de utilidade e relevância do artefato. Foi realizado um survey single entity, em uma empresa do setor elétrico brasileiro a partir de um questionário que foi enviado a executivos de diversas áreas abrangendo uma amostra de 75 gestores. O estudo revelou que a importância do orçamento para desempenhar as funções de planejamento e diálogo está associada à percepção de utilidade e de relevância do artefato. Especificamente, constatou-se que as funções de diálogo (ex post) estão mais fortemente associadas à utilidade para gestão e relevância para a tomada de decisões, do que as funções de planejamento (ex ante). Como consequência, são obtidos indícios de que o orçamento empresarial não deveria ser visto como um artefato estático de planejamento, e preocupações em relação à motivação, à comunicação, cujas funções são de diálogo, deveriam ser consideradas fundamentais para que o artefato possa ser explorado com maior intensidade no ambiente organizacional.
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Randhawa, Privia A., William Morrish, John T. Lysack, William Hu, Mayank Goyal, and Michael D. Hill. "Neuroradiology Using Secure Mobile Device Review." Canadian Journal of Neurological Sciences / Journal Canadien des Sciences Neurologiques 43, no. 4 (April 5, 2016): 529–32. http://dx.doi.org/10.1017/cjn.2016.40.
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AbstractBackground: Image review on computer-based workstations has made film-based review outdated. Despite advances in technology, the lack of portability of digital workstations creates an inherent disadvantage. As such, we sought to determine if the quality of image review on a handheld device is adequate for routine clinical use. Methods: Six CT/CTA cases and six MR/MRA cases were independently reviewed by three neuroradiologists in varying environments: high and low ambient light using a handheld device and on a traditional imaging workstation in ideal conditions. On first review (using a handheld device in high ambient light), a preliminary diagnosis for each case was made. Upon changes in review conditions, neuroradiologists were asked if any additional features were seen that changed their initial diagnoses. Reviewers were also asked to comment on overall clinical quality and if the handheld display was of acceptable quality for image review. Results: After the initial CT review in high ambient light, additional findings were reported in 2 of 18 instances on subsequent reviews. Similarly, additional findings were identified in 4 of 18 instances after the initial MR review in high ambient lighting. Only one of these six additional findings contributed to the diagnosis made on the initial preliminary review. Conclusions: Use of a handheld device for image review is of adequate diagnostic quality based on image contrast, sharpness of structures, visible artefacts and overall display quality. Although reviewers were comfortable with using this technology, a handheld device with a larger screen may be diagnostically superior.
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Christ, Olaf, and Ulrich G. Hofmann. "Video tracking of swimming rodents on a reflective water surface." Current Directions in Biomedical Engineering 1, no. 1 (September 1, 2015): 232–35. http://dx.doi.org/10.1515/cdbme-2015-0058.
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AbstractAnimal models are an essential testbed for new devices on their path from the bench to the patient. Potential impairments by brain stimulation are often investigated in water mazes to study spatial memory and learning. Video camera based tracking systems exist to quantify rodent behaviour, but reflections of ambient lighting on the water surface and artefacts due to the waves caused by the swimming animal cause errors. This often requires tweaking of algorithms and parameters, or even potentially modifying the lab setup. In the following, we provide a simple solution to alleviate these problem using a combination of region based tracking and independent multimodal background subtraction (IMBS) without hav ing to tweak a plethora of parameters.
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Dziekaniak, Cibele Dziekaniak, Leidy Gabriela Ariza Ariza, and José Vicente Vicente de Freitas. "Las salas verdes y la formación de educadoras(es) ambientales en Brasil." TED: Tecné, Episteme y Didaxis, no. 41 (May 24, 2017): 73. http://dx.doi.org/10.17227/01203916.6038.
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Aborda la relación entre las políticas ambientales y la formación de educadores ambientales en Brasil, a partir del análisis del Programa de Formación de Educadores ambientales (ProFEA), el cual reúne aspectos del Programa Nacional de Educación Ambiental (PNEA). En su metodología como Programa de Formación, ProFEA propone un conjunto de procedimientos denominados “4 Procesos Educacionales”, los cuales son: 1) Formación de Educadores Ambientales; 2) Educomunicación Socioambiental; 3) Educación en la escuela y en otros espacios y estructuras educadoras; 4) Educación en foros y organizaciones. El ProFEA cita a las Salas Verdes como ejemplo de estructuras educadoras, en este sentido, el articulo discute el potencial del Proyecto Sala Verde, del Ministerio de Medio Ambiente (MMA) en la formación de educadores ambientales para así problematizar su relación con los desafíos impuestos; igualmente, el potencial de las Salas Verdes como estructuras educadoras y democratizadoras del acceso a la información socioambiental. En la métodologia fueron utilizados como procedimientos técnicos la investigación bibliográfica y documental. La exploración documental se realizó en dos etapas, primero fue realizado el análisis de documento ProFEA, utilizando la herramienta tecnológica Atlas Ti (programa de computador de investigación cualitativa), con el Analisis Textual Discursiva (ATD) (una perspectiva fenomenológica que utiliza la descripción a partir de interpretar las palabras escritas en los textos y orienta la separación de los textos en unidades de significado, agrupando esas unidades para determinar las categorías iniciales, intermedias y finales), a fin de ampliar el conocimiento sobre las actividades de formación de educadores ambientales en Brasil, propuesta por el ProFEA. En su segunda etapa, la obtención de datos sobre el Proyecto Sala Verde utilizó notas de campo de naturaleza reflexiva, listas de discusiones de las Salas Verdes, publicaciones en la página del Ministerio de Medio Ambiente (MMA) y el blog del proyecto, también el análisis de documentos internos de diagnóstico e informes de gestión del Departamento de EducaciónAmbiental (DEA). La investigación refleja un proceso de generación de conocimiento en el cual lo sociocultural de este conocimiento es representado por una política. Se concluye que tal política puede ser definida por medio de un artefacto cognitivo en Educación Ambiental, una vez que permite conocer las actividades de formación de educadores ambientales de Brasil.
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Domingues, Diana, Dulcinéia Novaes, and Liliam Beatriz Maschio. "Muito além das imagens e Reengenharia da Cultura nos games, jornalismo operativo e sistemas enativos em práticas colaborativas transdisciplinares de Arte e TecnoCiência." Tríade: Revista de Comunicação, Cultura e Mídia 8, no. 19 (December 29, 2020): 81–112. http://dx.doi.org/10.22484/2318-5694.2020v8n19p81-112.
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A imagem, na revolução antropológica, vinda do ciberespaço misturado à vida, afasta-se da categoria de artefato para configurar eventos comunicacionais biocíbridos. As experiências do cotidiano se expandem para fora das fronteiras da tela, trazendo a ciência da interface mesclada aos cenários da Reengenharia da Cultura. Consideramos jogos, jornalismo operativo, sistemas enativos afetivos e redes sociais na Arte e Tecnociência, relacionados também à saúde e ao bem-estar. A partir da proposta ampliada de Benjamin, em relação ao "autor como produtor digital", nas trocas dos ambientes digitais, propomos feedbacks complexos, respostas autônomas, dispositivos sensoriais e a influência mútua dos corpos, ambiente e dados, trazendo a cognição incorporada em episódios e ocorrências misturadas à vida. As abordagens transdisciplinares enfrentam os desafios da vida do planeta, para além da imagem, configurando experiências estéticas e relações com sistemas enativos em graus de ubiquidade, mobilidade, liberdade e locatividade. Estamos discutindo os desafios da comunicação em um mundo tecnologicamente dependente, por meio de ontologias criativas pós-biológicas, em estudos de caso de nossas pesquisas. Os principais focos de análise são os limites borrados da vida e do ciberespaço numa “realidade reengenheirada”.
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Rodríguez Sánchez, Carlos Javier. "Ambientes de aprendizaje colaborativo y creación colectiva en 3 weeks bside project experience." Revista SOBRE 2 (July 6, 2016): 09–24. http://dx.doi.org/10.30827/5046.
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El presente artículo propone, una aproximación, revisión y reflexión socio-crítica del ambiente de aprendizaje colaborativo como agente pedagógico, y su relación con las comunidades de prácticas artísticas a travésde la creación colectiva. El principal objetivo es introducir el caso de estudio «3 weeks bside project experience» a través del método de investigación-acción participante, el análisis de diferentes conceptos y de sus aspectos teóricos y prácticos asociados, la fotografía y culturavisual ha actuado como herramienta de expresión y recogida de información. Encuadrado en un universo de desarrollo de autogestióneducativa, el proyecto ha basado su proceso en el aprendizaje colaborativo, focalizándolo en la construcción de un discurso conjunto en tornoa la idea del territorio, y representado a través de una publicación e instalación expositiva site specific colectiva como meta común y procesosimbólico asociado. La experiencia del proyecto permitió establecer una serie de posicionamientos que proponen una transferencia de lasformas de interacción social relacionadas con la construcción de ambientes de pertenencia, participación y transformación, el cuestionamientodel rol del profesor entendido como un agente participante y dinamizador, o la creación colectiva de un proyecto, incidiendo en laimportancia del proceso construido dentro de una comunidad temporal, más allá de la producción de artefactos culturales. Se abordarondichas estructuras dialógicas, donde la convivencia supusiera un espacio de reflexión crítica personal y común sobre el posicionamiento como autores, el entorno socio-cultural próximo y el vínculo dentro de la educación, artes y cultura visual focalizado en la capacidad del trabajo horizontal y flexible que propone la configuración de un ambiente de aprendizajecolaborativo.
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Hwang, Amy S., Khai N. Truong, Jill I. Cameron, Eva Lindqvist, Louise Nygård, and Alex Mihailidis. "Co-Designing Ambient Assisted Living (AAL) Environments: Unravelling the Situated Context of Informal Dementia Care." BioMed Research International 2015 (2015): 1–12. http://dx.doi.org/10.1155/2015/720483.
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Ambient assisted living (AAL) aims to help older persons “age-in-place” and manage everyday activities using intelligent and pervasive computing technology. AAL research, however, has yet to explore how AAL might support or collaborate with informal care partners (ICPs), such as relatives and friends, who play important roles in the lives and care of persons with dementia (PwDs). In a multiphase codesign process with six (6) ICPs, we envisioned how AAL could be situated to complement their care. We used our codesigned “caregiver interface” artefacts astriggersto facilitate envisioning of AAL support and unpack the situated, idiosyncratic context within which AAL aims to assist. Our findings suggest that AAL should be designed to support ICPs in fashioning “do-it-yourself” solutions that complement tacitly improvised care strategies and enable them to try, observe, and adapt to solutions over time. In this way, an ICP could decide which activities to entrust to AAL support, when (i.e., scheduled or spontaneous) and how a system should provide support (i.e., using personalized prompts based on care experience), and when adaptations to system support are needed (i.e., based alerting patterns and queried reports). Future longitudinal work employing participatory, design-oriented methods with care dyads is encouraged.
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Skalicky, David, Vaclav Koucky, Daniel Hadraba, Martin Viteznik, Martin Dub, and Frantisek Lopot. "Detection of Respiratory Phases in a Breath Sound and Their Subsequent Utilization in a Diagnosis." Applied Sciences 11, no. 14 (July 16, 2021): 6535. http://dx.doi.org/10.3390/app11146535.
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Detection of lung sounds and their propagation is a powerful tool for analysing the behaviour of the respiratory system. A common approach to detect the respiratory sounds is lung auscultation, however, this method has significant limitations including low sensitivity of human ear or ambient background noise. This article targets the major limitations of lung auscultation and presents a new approach to analyse the respiratory sounds and visualise them together with the respiratory phases. The respiratory sounds from 41 patients were recorded and filtered to eliminate the ambient noise and noise artefacts. The filtered signal is processed to identify the respiratory phases. The article also contains an approach for removing the noise that is very difficult to filter but the removal is crucial for identifying the respiratory phases. Finally, the respiratory phases are overlaid with the frequency spectrum which simplifies the orientation in the recording and additionally offers the information on the inter-individual ratio of the inhalation and exhalation phases. Such interpretation provides a powerful tool for further analysis of lung sounds, simplifythe diagnosis of various types of respiratory tract dysfunctions, and returns data which are comparable among the patients.
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Cheng, Feng, Jianghai Xia, Kai Zhang, Changjiang Zhou, and Jonathan B. Ajo-Franklin. "Phase-weighted slant stacking for surface wave dispersion measurement." Geophysical Journal International 226, no. 1 (March 15, 2021): 256–69. http://dx.doi.org/10.1093/gji/ggab101.
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SUMMARY Surface wave retrieval from ambient noise records using seismic interferometry techniques has been widely used for multiscale shear wave velocity (Vs) imaging. One key step during Vs imaging is the generation of dispersion spectra and the extraction of a reliable dispersion curve from the retrieved surface waves. However, the sparse array geometry usually affects the ability for high-frequency (>1 Hz) seismic signals’ acquisition. Dispersion measurements are degraded by array response due to sparse sampling and often present smeared dispersion spectra with sidelobe artefacts. Previous studies usually focus on interferograms’ domain (e.g. cross-correlation function) and attempt to enhance coherent signals before dispersion measurement. We propose an alternative technique to explicitly deblur dispersion spectra through use of a phase-weighted slant-stacking algorithm. Numerical examples demonstrate the strength of the proposed technique to attenuate array responses as well as incoherent noise. Three different field examples prove the flexibility and superiority of the proposed technique: the first data set consists of ambient noise records acquired using a nodal seismometer array; the second data set utilizes distributed acoustic sensing (DAS) and a marine fibre-optic cable to acquire a similar ambient noise data set; the last data set is a vibrator-based active-source surface wave data. The enhanced dispersion measurements provide cleaner and higher-resolution spectra without distortions which will assist both human interpreters as well as ML algorithms in efficiently picking curves for subsequent Vs inversion.
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Morales Martín, Luz Yolanda, Edmundo Leiva-lobos, and Héctor Antillanca Espina. "Análisis de un modelo conversacional para ambientes virtuales de aprendizaje." Ciencia e Ingeniería Neogranadina 17, no. 1 (June 1, 2007): 129–38. http://dx.doi.org/10.18359/rcin.1101.
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Este artículo analiza los límites de un modelo para facilitar el aprendizaje colaborativo en ambientes electrónicos llamado Modelo de Conversación para el Aprendizaje (MCA). Este análisis demanda cuestionar los supuestos implícitos que tienen nociones usadas por los autores del modelo tales como la conectividad comunicativa y el modelo conversacional adoptado. La propuesta termina haciendo reflexiones sobre el diálogo, proponiendo líneas concretas para reparar el MCA y haciendo indicaciones sobre artefactos más concretos que se deben incluir en una nueva versión del modelo.
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Silva, Renata Lourinho da, Denivaldo Pantoja da Silva, and Maria Katiane Miranda Ribeiro. "A prática cultural da construção do Matapi: possibilidades para o ensino de Geometria utilizando o Geogebra." Matemática e Ciência: construção, conhecimento e criatividade 3, no. 2 (December 22, 2020): 113–25. http://dx.doi.org/10.5752/p.2674-9416.2020v3n2p113-125.
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Neste artigo, apresentamos uma experiência com a construção do artefato matapi, utilizando o software Geogebra, a partir de sua construção física in loco. Foi desenvolvida no curso de formação de professores para a educação do campo, que abordou o tema: Construção e uso do matapi: diálogos entre tempo escola e tempo comunidade. Nosso objetivo é apresentar possibilidades para abordar algumas noções da geometria em sala de aula, partindo da construção do matapi, utilizando o Geogebra como instrumento didático. Para alcançar esse objetivo, apresentamos algumas imagens do matapi, que foi construído no local, para, em seguida, representá-lo no ambiente virtual com auxílio do software. Os resultados mostram que se pode promover a construção de algumas noções matemáticas da geometria plana e espacial a partir da construção física do artefato
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Todorovska-Rasic, Milica, and Niko Radulovic. "Organic thiocyanates - glucosinolate enzymatic degradation products or artefacts of the isolation procedure?" Facta universitatis - series: Physics, Chemistry and Technology 18, no. 2 (2020): 77–87. http://dx.doi.org/10.2298/fupct2002077t.
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Glucosinolates are abundant in plants of the order Brassicales, and they are degraded by myrosinases into various organic breakdown products: isothiocyanates, thiocyanates, nitriles, etc., depending on their structure, conditions of hydrolysis, the presence of certain protein cofactors. Their most common hydrolysis products are isothiocyanates, while simple nitriles, epithionitriles, and thiocyanates are produced occasionally. Organic thiocyanates are described from a very limited number of Brassicales taxa. Up to now benzyl, (4-hydroxyphenyl)methyl, (4-methoxyphenyl)methyl, 4- methylthiobutyl, and allyl thiocyanates were reported as products of glucosinolates autolysis. The present review summarizes the knowledge on the mechanism of organic thiocyanate formation from the corresponding thioglucosides. The enzymatic formation of organic thiocyanates is believed to be enabled by thiocyanate-forming protein (TFP), but they could be formed via metabolic routes that do not involve TFP. All of the reported thiocyanates are produced from stable (carbo)cationic species that allow an isomerization of an isothiocyanate to thiocyanate, and vice versa. Although the possibility that thiocyanates can be biosynthesized in plats under certain conditions cannot be dismissed, allyl thiocyanate can be a thermal isomerization artefact of the original isothiocyanate that is formed in the heated zones of the gas chromatograph, while other thiocyanates could form in an aqueous medium via heterolytic dissociation to ambident nucleophilic SCN- and its recapture. One should always be aware of this analytical shortcoming when concluding on the presence and quantity of these specific (iso)thiocyanantes in the analyzed sample.
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Bernardo, Cláudio Gonçalves, Ivette Kafure Muñoz, and Tiago Barros Pontes e. Silva. "Pessoa com deficiência visual e a acessibilidade à informação para mobilidade indoor." RDBCI: Revista Digital de Biblioteconomia e Ciência da Informação 18 (November 24, 2020): e020036. http://dx.doi.org/10.20396/rdbci.v18i00.8661391.
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Introdução: A lei de acessibilidade 10.098 de 2000 estabelece normas e critérios para promover acessibilidade às pessoas com deficiência. Dados do censo realizado pelo IBGE em 2013 informam que do total de 146,3 milhões de pessoas acima de 18 anos, aproximadamente 5,27 milhões são pessoas com deficiência visual (PDV), o equivalente a 3,6%. Método: Considerando que a informação quando é proporcionada de maneira correta leva melhores condições de mobilidade à PDV, este artigo apresenta a proposta de desenvolvimento de artefato eletrônico que lhe proporcione informação na sua mobilidade em qualquer espaço físico interno, posto que disponibiliza informações sobre distância, profundidade e lateralidade do ambiente, sendo categorizado como um mapa auditivo. Resultados: A partir da perspectiva da Ciência da Informação, abordando conceitos de estudo de usuários, acessibilidade e tecnologia assistiva a proposta trata dos desafios de acesso à informação e também de desafios ao acesso físico. O artefato foi desenvolvido utilizando o sistema Dosvox que é amplamente utilizado por PDV. A Biblioteca Central (BCE) da Universidade de Brasília (UnB) foi o espaço físico escolhido como o local contemplado para o desenho do artefato, por já possuir diversos recursos de acessibilidade à informação para a PDV. Conclusão: O objetivo de proporcionar acessibilidade à informação por meio do artefato desenvolvido foi atingido porque orienta a PDV em sua mobilidade indoor.
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Magnín, Lucía A., Enrique Daniel Terranova, and Virginia Lynch. "Análisis espacial del sitio Amigo Oeste, Meseta de Somuncurá (Río Negro, Argentina)." Revista del Museo de La Plata 5, no. 1 (April 22, 2020): 80–96. http://dx.doi.org/10.24215/25456377e096.
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En este trabajo analizamos las distribuciones espaciales de los artefactos líticos en Amigo Oeste, un sitio al aire libre ubicado en la región de la meseta de Somuncurá (Río Negro, Argentina). Una de las principales singularidades del sitio es que una gran proporción de las evidencias arqueológicas registradas consiste en Puntas Cola de Pescado (PCP), artefactos de diagnóstico asignados a la transición Pleistoceno-Holoceno, lo que demuestra su relevancia para el estudio del poblamiento temprano de las Américas. El sitio se extiende tanto en la cima como en la ladera sureste de un cerro de 84m de desnivel.El relevamiento de información espacial en este sitio se realizó mediante 292 unidades transectas y recolección puntual de artefactos registrados mediante GPS no diferencial y teodolito electrónico. Se recolectaron 2575 artefactos líticos entre núcleos, artefactos formatizados y artefactos no formatizados. Hasta el momento el sitio ha sido interpretado como un lugar de visualización para control del entorno (que pudo haber sido usado como campo de caza), donde se realizaron tareas de reequipamiento de PCP, así como otras actividades relacionadas con la cacería.Con el objetivo de explorar patrones espaciales en los indicadores de actividades realizadas en el sitio, los datos generados en trabajos previos (la ubicación de los artefactos y los atributos generados desde el punto de vista tecno-morfológico y morfológico-funcional, así como información ambiental) se integraron en un Sistema de Información Geográfica, y se realizó un análisis espacial exploratorio para definir estadísticamente la existencia de agrupaciones en los artefactos, en los atributos asociados a ellos, así como el número de agrupaciones y su ubicación. Este trabajo permitió lograr un mayor conocimiento sobre las áreas de actividad en el sitio y en su entorno inmediato.