254 research outputs found

    Blended Spaces: Reimagining Civic Education in a Digital Era

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    While traditional civic education in the United States is inextricably linked to notions of a public sphere, this paper argues that the digital era requires a reimagining of this premise. The opaque nature of digital spaces makes it difficult for young people to understand how large of an audience they are interacting with and to what extent a conversation that may feel private is rebounding across public contexts. In this conceptual paper, we (1) use semiotic squares to present publicly private and privately public as two ways to reinterpret traditional presumptions about the role of “the public” in civic education and (2) present the implications of these blended spaces for civic education and civic learning. The paper asks, what does it mean to prepare young people for interaction in the “public” sphere within our classrooms today? By drawing on a vignette of teacher practice, we articulate what civic education could be for students around the world in the 21st century

    Katsaus viestialan viimeaikaiseen kehitykseen

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    Artikkelin johdannossa todetaan, että "Teletekniikan kehitys on kaikilla aloilla nopeaa ja laaja-alaista, joten sen tarkastelussa on rajoituttava vain eräisiin oleellisimpiin ja yleistä mielenkiintoa omaaviin kohteisiin." Ensimmäisessä luvussa "teleteknillinen kehitys ulkomailla" tarkastellaan aluksi viestinsiirtotekniikan osalta radioyhteyksien laadun parantamista todeten, että "HF-alueen ahtauden ja kasvaneen informaatiomäärän takia ollaan vähitellen siirtymässä digitaaliseen viestinsiirtoon." Toisena tarkasteluun on otettu RADA-järjestelmä (Random Access Discreate Address), jossa leveä kaista vartaan monelle käyttäjälle samanaikaisesti. Seuraavana käsitellään elektronisia keskuksia ja yhdistettyjä puhelinverkkoja. "Ensimmäiset elektroniset puhelinkeskukset on jo otettu kokeilumielessä yleiseen liikenteen käyttöön." Uusista viestivälineistä mainitaan muun muassa näköpuhelin ja kuvataan lyhyesti ionosfääritutkimuksen kohteita sekä ydinräjähdysten vaikutusta radioyhteyksiin. Katsauksessa käsitellään seuraavaksi lyhyesti mikroelektroniikan kehittymistä ja laaja-alaisesti tietoliikenteen yleistä kehitystä, tuoden esille muun muassa puhelin- ja telextilastoja maailmanlaajuisesti, puhelinliikenteen automatisoinnin ja valtamerikaapeleiden sekä tietoliikennesatelliittien tilannetta. Lisäksi käsitellään, digitaalisten tietojen kaukosiirtoa, yleisradio- ja televisiotoimintaa sekä yksityiskohtana nk. "kuumaa linjaa". Luvun lopussa tarkastellaan sotilaallisia viestijärjestelmiä, kuten muun muassa USA:n strategista viestiverkkoa sekä eräitä ulkomaisia viestivälineitä.Luvussa, "Teletekniikan kehitys kotimaassa", käsitellään ensin lyhyesti kehitystä puolustuslaitoksessa todeten esimerkiksi yhtenä uutena välineenä kenttäsuuntaradiot. Seuraavana tarkastellaan siviilisektorin radiotoiminnallisen ja -teknillisen kehityksen puitteissa muun muassa Posti- ja lennätinlaitosta ja Yleisradion toiminnan kattavuutta. Puhelin- ja lennätintoiminnan puitteissa esitellään Posti- ja lennätinhallitus ja muut toimiluvan saaneet puhelinlaitokset. Artikkelin lopuksi tarkastellaan lyhyesti viestialan teollisuuden toimijoita tuotteineen ja totaalista viestitoimintaa todeten yhtenä esimerkkinä, että asetus viestialan neuvottelukunnasta annettiin vuoden 1962 lopussa

    Differentiating Fissure-Fed Lava Flow Types and Facies Using RADAR and LiDAR: An Example from the 2014–2015 Holuhraun Lava Flow-field

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    Distinguishing between lava types and facies using remote sensing data is important for interpreting the emplacement history of lava flow-fields on Earth and other planetary bodies. Lava facies typically include a mixture of lava types and record the collective emplacement history of material preserved at a particular location. We seek to determine if lava facies in the 2014–2015 Holuhraun lava flow-field are discernible using radar roughness analysis. Furthermore, we also seek to distinguish between lava types using high resolution Light Detection and Ranging (LiDAR) data. We extracted circular polarization ratios (CPR) from the Uninhabited Aerial Vehicle Synthetic Aperture Radar and cross-polarization (VH/VV) data from the Sentinel-1 satellite to analyze the surface roughness of three previously mapped lava facies: rubbly, spiny, and undifferentiated rubbly–spiny. Using the Kruskal-Wallis test, we reveal that all but one pair of the facies are statistically separable. However, the populations overlap by 88%–89% for CPR and 64%–67% for VH/VV. Therefore, owing to large sample populations (n \u3e 2 × 105), slight differences in radar data may be used to probabilistically infer the presence of a particular facies, but not directly map them. We also calculated the root-mean-square slope and Hurst exponents of five different lava types using LiDAR topography (5 cm/pixel). Our results show minute differences between most of the lava types, with the exception of the rubbly pāhoehoe, which is discernible at 1σ. In brief, the presence of “transitional” lava types (e.g., rubbly pāhoehoe) within fissure-fed lava flow-fields complicates remote sensing-based mapping

    Effects of fenofibrate on renal function in patients with type 2 diabetes mellitus: the Fenofibrate Intervention and Event Lowering in Diabetes (FIELD) Study

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    Abstract Aims/hypothesis Fenofibrate caused an acute, sustained plasma creatinine increase in the Fenofibrate Intervention and Event Lowering in Diabetes (FIELD) and Action to Control Cardiovascular Risk in Diabetes (ACCORD) studies. We assessed fenofibrate’s renal effects in a FIELD washout sub-study. Methods Type 2 diabetic patients (n=9795) aged 50 to 75 years were randomly assigned to fenofibrate (n=4895) or placebo (n=4900) for 5 years, after 6 weeks fenofibrate run-in. Albuminuria (urinary albumin:creatinine ratio) measured at baseline, year 2 and close-out) and estimated GFR, measured 4 to 6 monthly according to the Modification of Diet in Renal Disease study, were pre-specified endpoints. Plasma creatinine was re-measured 8 weeks after treatment cessation at close-out (washout sub-study, n=661). Analysis was by intention-to-treat. Results During fenofibrate run-in, plasma creatinine increased by 10.0 µmol/l (p<0.001), but quickly reversed on placebo assignment. It remained higher on fenofibrate than on placebo, but the chronic rise was slower (1.62 µmol/l vs 1.89 µmol/l annually, p=0.01), with less estimated GFR loss (1.19 vs 2.03 ml min−1 1.73 m−2 annually, p<0.001). After washout, estimated GFR had fallen less from baseline on fenofibrate (1.9 ml min−1 1.73 m−2, p=0.065) than on placebo (6.9 ml min−1 1.73 m−2, p<0.001), sparing 5.0 ml min−1 1.73 m−2 (95% CI 2.3-7.7, p<0.001). Greater preservation of estimated GFR with fenofibrate was observed during greater reduction over the active run-in period (pre-randomisation) of triacylglycerol (n=186 vs 170) and baseline hypertriacylglycerolaemia (n=89 vs 80) alone, or combined with low HDL-cholesterol (n=71 vs 60). Fenofibrate reduced urine albumin concentrations and hence albumin:creatinine ratio by 24% vs 12% (p<0.001; mean difference 14% [95% CI 9-18]; p<0.001), with 14% less progression and 18% more albuminuria regression (p<0.001) than in participants on placebo. End-stage renal event frequency was similar (n=21 vs 26, p=0.48). Conclusions/interpretation Fenofibrate reduced albuminuria and slowed estimated GFR loss over 5 years, despite initially and reversibly increasing plasma creatinine. Fenofibrate may delay albuminuria and GFR impairment in type 2 diabetes patients. Confirmatory studies are merited. Trial registration: ISRCTN64783481 Funding: The study was funded by grants from Laboratoires Fournier, Dijon, France (now part of Solvay and Abbott Pharmaceuticals) and the NHMRC of Australia.Laboratoires Fournier, Dijon, France (now part of Solvay and Abbott Pharmaceuticals

    Effects of fenofibrate on renal function in patients with type 2 diabetes mellitus: the Fenofibrate Intervention and Event Lowering in Diabetes (FIELD) Study

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    Abstract Aims/hypothesis Fenofibrate caused an acute, sustained plasma creatinine increase in the Fenofibrate Intervention and Event Lowering in Diabetes (FIELD) and Action to Control Cardiovascular Risk in Diabetes (ACCORD) studies. We assessed fenofibrate’s renal effects in a FIELD washout sub-study. Methods Type 2 diabetic patients (n=9795) aged 50 to 75 years were randomly assigned to fenofibrate (n=4895) or placebo (n=4900) for 5 years, after 6 weeks fenofibrate run-in. Albuminuria (urinary albumin:creatinine ratio) measured at baseline, year 2 and close-out) and estimated GFR, measured 4 to 6 monthly according to the Modification of Diet in Renal Disease study, were pre-specified endpoints. Plasma creatinine was re-measured 8 weeks after treatment cessation at close-out (washout sub-study, n=661). Analysis was by intention-to-treat. Results During fenofibrate run-in, plasma creatinine increased by 10.0 µmol/l (p<0.001), but quickly reversed on placebo assignment. It remained higher on fenofibrate than on placebo, but the chronic rise was slower (1.62 µmol/l vs 1.89 µmol/l annually, p=0.01), with less estimated GFR loss (1.19 vs 2.03 ml min−1 1.73 m−2 annually, p<0.001). After washout, estimated GFR had fallen less from baseline on fenofibrate (1.9 ml min−1 1.73 m−2, p=0.065) than on placebo (6.9 ml min−1 1.73 m−2, p<0.001), sparing 5.0 ml min−1 1.73 m−2 (95% CI 2.3-7.7, p<0.001). Greater preservation of estimated GFR with fenofibrate was observed during greater reduction over the active run-in period (pre-randomisation) of triacylglycerol (n=186 vs 170) and baseline hypertriacylglycerolaemia (n=89 vs 80) alone, or combined with low HDL-cholesterol (n=71 vs 60). Fenofibrate reduced urine albumin concentrations and hence albumin:creatinine ratio by 24% vs 12% (p<0.001; mean difference 14% [95% CI 9-18]; p<0.001), with 14% less progression and 18% more albuminuria regression (p<0.001) than in participants on placebo. End-stage renal event frequency was similar (n=21 vs 26, p=0.48). Conclusions/interpretation Fenofibrate reduced albuminuria and slowed estimated GFR loss over 5 years, despite initially and reversibly increasing plasma creatinine. Fenofibrate may delay albuminuria and GFR impairment in type 2 diabetes patients. Confirmatory studies are merited. Trial registration: ISRCTN64783481 Funding: The study was funded by grants from Laboratoires Fournier, Dijon, France (now part of Solvay and Abbott Pharmaceuticals) and the NHMRC of Australia.Laboratoires Fournier, Dijon, France (now part of Solvay and Abbott Pharmaceuticals

    Gas phase Elemental abundances in Molecular cloudS (GEMS) VII. Sulfur elemental abundance

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    Gas phase Elemental abundances in molecular CloudS (GEMS) is an IRAM 30m large program aimed at determining the elemental abundances of carbon (C), oxygen (O), nitrogen (N), and sulfur (S) in a selected set of prototypical star-forming filaments. In particular, the elemental abundance of S remains uncertain by several orders of magnitude and its determination is one of the most challenging goals of this program. We have carried out an extensive chemical modeling of the fractional abundances of CO, HCO+^+, HCN, HNC, CS, SO, H2_2S, OCS, and HCS+^+ to determine the sulfur depletion toward the 244 positions in the GEMS database. These positions sample visual extinctions from AV_V \sim 3 mag to >>50 mag, molecular hydrogen densities ranging from a few 103^3~cm3^{-3} to 3×\times106^6~cm3^{-3}, and Tk_k \sim 10-35 K. Most of the positions in Taurus and Perseus are best fitted assuming early-time chemistry, t=0.1 Myr, ζH2\zeta_{H_2}\sim (0.5-1)×\times1016^{-16} s1^{-1}, and [S/H]\sim1.5×\times106^{-6}. On the contrary, most of the positions in Orion are fitted with t=1~Myr and ζH2\zeta_{H_2}\sim 1017^{-17} s1^{-1}. Moreover, \sim40% of the positions in Orion are best fitted assuming the undepleted sulfur abundance, [S/H]\sim1.5×\times105^{-5}. Our results suggest that sulfur depletion depends on the environment. While the abundances of sulfur-bearing species are consistent with undepleted sulfur in Orion, a depletion factor of \sim20 is required to explain those observed in Taurus and Perseus. We propose that differences in the grain charge distribution in the envelopes of the studied clouds might explain these variations. The shocks associated with past and ongoing star formation could also contribute to enhance [S/H] in Orion.Comment: 22 pages, 15 figures, Astronomy and Astrophysics, in pres

    Gas phase Elemental abundances in Molecular cloudS (GEMS) VIII. Unlocking the CS chemistry: the CH + S\rightarrow CS + H and C2_2 + S\rightarrow CS + C reactions

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    We revise the rates of reactions CH + S -> CS + H and C_2 + S -> CS + C, important CS formation routes in dark and diffuse warm gas. We performed ab initio calculations to characterize the main features of all the electronic states correlating to the open shell reactants. For CH+S we have calculated the full potential energy surfaces for the lowest doublet states and the reaction rate constant with a quasi-classical method. For C_2+S, the reaction can only take place through the three lower triplet states, which all present deep insertion wells. A detailed study of the long-range interactions for these triplet states allowed to apply a statistic adiabatic method to determine the rate constants. This study of the CH + S reaction shows that its rate is nearly independent on the temperature in a range of 10-500 K with an almost constant value of 5.5 10^{-11} cm^3/s at temperatures above 100~K. This is a factor \sim 2-3 lower than the value obtained with the capture model. The rate of the reaction C_2 + S depends on the temperature taking values close to 2.0 10^{-10} cm^3/s at low temperatures and increasing to 5. 10^{-10} cm^3/s for temperatures higher than 200~K. Our modeling provides a rate higher than the one currently used by factor of \sim 2. These reactions were selected for involving open-shell species with many degenerate electronic states, and the results obtained in the present detailed calculations provide values which differ a factor of \sim 2-3 from the simpler classical capture method. We have updated the sulphur network with these new rates and compare our results in the prototypical case of TMC1 (CP). We find a reasonable agreement between model predictions and observations with a sulphur depletion factor of 20 relative to the sulphur cosmic abundance, but it is not possible to fit all sulphur-bearing molecules better than a factor of 10 at the same chemical time.Comment: 13 pages, 10 figure
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