@article{HeisigMatthewes2022,
  author    = {Heisig, Jan Paul and Matthewes, S{\"o}nke Hendrik},
  title     = {No evidence that strict educational tracking improves student performance through classroom homogeneity},
  series = {Zeitschrift f{\"u}r Soziologie},
  volume    = {51},
  journal   = {Zeitschrift f{\"u}r Soziologie},
  number    = {1},
  publisher = {de Gruyter Oldenbourg},
  address   = {Berlin},
  issn      = {0340-1804},
  doi       = {10.1515/zfsoz-2022-0001},
  pages     = {99 -- 111},
  year      = {2022},
  abstract  = {In a recent contribution to this journal, Esser and Seuring (2020) draw on data from the National Educational Panel Study to attack the widespread view that tracking in lower secondary education exacerbates inequalities in student outcomes without improving average student performance. Exploiting variation in the strictness of tracking across 13 of the 16 German federal states (e. g., whether teacher recommendations are binding), Esser and Seuring claim to demonstrate that stricter tracking after grade 4 results in better performance in grade 7 and that this can be attributed to the greater homogeneity of classrooms under strict tracking. We show these conclusions to be untenable: Esser and Seuring's measures of classroom composition are highly dubious because the number of observed students is very small for many classrooms. Even when we adopt their classroom composition measures, simple corrections and extensions of their analysis reveal that there is no meaningful evidence for a positive relationship between classroom homogeneity and student achievement - the channel supposed to mediate the alleged positive effect of strict tracking. We go on to show that students from more strictly tracking states perform better already at the start of tracking (grade 5), which casts further doubt on the alleged positive effect of strict tracking on learning progress and leaves selection or anticipation effects as more plausible explanations. On a conceptual level, we emphasize that Esser and Seuring's analysis is limited to states that implement different forms of early tracking and cannot inform us about the relative performance of comprehensive and tracked systems that is the focus of most prior research.},
  language  = {en}
}
@misc{FilacchioneGroussinHernyetal.2019,
  author    = {Filacchione, Gianrico and Groussin, Olivier and Herny, Clemence and Kappel, David and Mottola, Stefano and Oklay, Nilda and Pommerol, Antoine and Wright, Ian and Yoldi, Zurine and Ciarniello, Mauro and Moroz, Lyuba and Raponi, Andrea},
  title     = {Comet 67P/CG Nucleus Composition and Comparison to Other Comets},
  series = {Space science reviews},
  volume    = {215},
  journal   = {Space science reviews},
  number    = {19},
  publisher = {Springer},
  address   = {Dordrecht},
  issn      = {0038-6308},
  doi       = {10.1007/s11214-019-0580-3},
  pages     = {46},
  year      = {2019},
  abstract  = {We review our current knowledge of comet 67P/Churyumov-Gerasimenko nucleus composition as inferred from measurements made by remote sensing and in-situ instruments aboard Rosetta orbiter and Philae lander. Spectrophotometric properties (albedos, color indexes and Hapke parameters) of 67P/CG derived by Rosetta are discussed in the context of other comets previously explored by space missions. Composed of an assemblage made of ices, organic materials and minerals, cometary nuclei exhibit very dark and red surfaces which can be described by means of spectrophotometric quantities and reproduced with laboratory measurements. The presence of surface water and carbon dioxide ices was found by Rosetta to occur at localized sites where the activity driven by solar input, gaseous condensation or exposure of pristine inner layers can maintain these species on the surface. Apart from these specific areas, 67P/CG's surface appears remarkably uniform in composition with a predominance of organic materials and minerals. The organic compounds contain abundant hydroxyl group and a refractory macromolecular material bearing aliphatic and aromatic hydrocarbons. The mineral components are compatible with a mixture of silicates and fine-grained opaques, including Fe-sulfides, like troilite and pyrrhotite, and ammoniated salts. In the vicinity of the perihelion several active phenomena, including the erosion of surface layers, the localized activity in cliffs, fractures and pits, the collapse of overhangs and walls, the transfer and redeposition of dust, cause the evolution of the different regions of the nucleus by inducing color, composition and texture changes.},
  language  = {en}
}