Dynamics of spatially homogeneous locally rotationally symmetric solutions of the Einstein-Vlasov equations

The dynamics of the Einstein-Vlasov equations for a class of cosmological models with four Killing vectors is discussed in the case of massive particles. It is shown that in all models analysed the solutions with massive particles are asymptotic to solutions with massless particles at early times. It is also shown that in Bianchi types I and II the solutions with massive particles are asymptotic to dust solutions at late times. That Bianchi type III models are also asymptotic to dust solutions at late times is consistent with our results but is not established by them.Comment: 21 pages, 2 figure

The Nature and Methodological Implications of the Cognitive Representation of Products

A general relationship is proposed wherein more abstract attributes are likely to resemble continuous dimensions while more concrete attributes are likely to resemble dichotomous features. While some methodologies assume dimensional representations, others assume feature-based representations. This suggests that dimensional methods may better capture abstract product representations while feature-based methods may better capture concrete representations. The results of two studies that support both the general relationship and its methodological implications are reported

Spectral/hp element methods: recent developments, applications, and perspectives

The spectral/hp element method combines the geometric flexibility of the classical h-type finite element technique with the desirable numerical properties of spectral methods, employing high-degree piecewise polynomial basis functions on coarse finite element-type meshes. The spatial approximation is based upon orthogonal polynomials, such as Legendre or Chebychev polynomials, modified to accommodate C0-continuous expansions. Computationally and theoretically, by increasing the polynomial order p, high-precision solutions and fast convergence can be obtained and, in particular, under certain regularity assumptions an exponential reduction in approximation error between numerical and exact solutions can be achieved. This method has now been applied in many simulation studies of both fundamental and practical engineering flows. This paper briefly describes the formulation of the spectral/hp element method and provides an overview of its application to computational fluid dynamics. In particular, it focuses on the use the spectral/hp element method in transitional flows and ocean engineering. Finally, some of the major challenges to be overcome in order to use the spectral/hp element method in more complex science and engineering applications are discussed

Back on track? How civic learning opportunities widen the political knowledge gap in a tracked education system

This article examines how different civic learning opportunities relate to students’ political knowledge in different school tracks. Existing studies have found that citizenship teaching can not only enhance overall levels of civic outcomes but also mitigate inequalities. However, educational achievement studies emphasize the risk of a tracked school context exacerbating the general knowledge gap. Combining these findings, we do not know whether efforts in the vocational track to enhance civic outcomes can still reduce civic inequalities. This study relies on the International Civic and Citizenship Education Study (ICCS) 2016 data. It uses multilevel analysis to examine how the civic learning opportunities schools offer (as perceived by students) are related to civic knowledge across different tracks. It finds that cross-track differences in civic knowledge are not smaller in schools rich in civic learning opportunities. We provisionally propose that this is due to differences across tracks in the levels and the nature of the civic learning opportunities provided

Downregulation of genes with a function in axon outgrowth and synapse formation in motor neurones of the VEGF(delta/delta) mouse model of amyotrophic lateral sclerosis

Background: Vascular endothelial growth factor (VEGF) is an endothelial cell mitogen that stimulates vasculogenesis. It has also been shown to act as a neurotrophic factor in vitro and in vivo. Deletion of the hypoxia response element of the promoter region of the gene encoding VEGF in mice causes a reduction in neural VEGF expression, and results in adult-onset motor neurone degeneration that resembles amyotrophic lateral sclerosis (ALS). Investigating the molecular pathways to neurodegeneration in the VEGF(delta/delta) mouse model of ALS may improve understanding of the mechanisms of motor neurone death in the human disease. Results: Microarray analysis was used to determine the transcriptional profile of laser captured spinal motor neurones of transgenic and wild-type littermates at 3 time points of disease. 324 genes were significantly differentially expressed in motor neurones of presymptomatic VEGF(delta/delta) mice, 382 at disease onset, and 689 at late stage disease. Massive transcriptional downregulation occurred with disease progression, associated with downregulation of genes involved in RNA processing at late stage disease. VEGF(delta/delta) mice showed reduction in expression, from symptom onset, of the cholesterol synthesis pathway, and genes involved in nervous system development, including axonogenesis, synapse formation, growth factor signalling pathways, cell adhesion and microtubule-based processes. These changes may reflect a reduced capacity of VEGF(delta/delta) mice for maintenance and remodelling of neuronal processes in the face of demands of neural plasticity. The findings are supported by the demonstration that in primary motor neurone cultures from VEGF(delta/delta) mice, axon outgrowth is significantly reduced compared to wild-type littermates. Conclusions: Downregulation of these genes involved in axon outgrowth and synapse formation in adult mice suggests a hitherto unrecognized role of VEGF in the maintenance of neuronal circuitry. Dysregulation of VEGF may lead to neurodegeneration through synaptic regression and dying-back axonopathy

A comparative study on the efficacy of four anthelmintics on some important reindeer parasites

Four anthelmintic preparations were tested against some of the most important parasites of reindeer, i.e. warble fly (Oedemagena tarandi), nostril fly (Cephenemyia trompe), brainworm (Elaphostrongylus rangiferi), and lungworm (Dictyocaulus viviparus). Their efficacy against intestinal nematodes was also registered. Test drugs were Fenthion (Bayer), Fenbendazole (Hoechst), Mebendazole (Janssen), and Ivermectin (Merk Sharp & Dohme). Against O. tarandi and C. trompe Ivermectin was 100% effective and Fenthion 86 and 100% respectively. The efficacy of Fen- and Mebendazole against these parasites was not significant. Against E. rangiferi the benzimidazole compounds were highly effective, with Mebendazole a bit ahead. Ivermectin had a moderate effect and Fenthion had no effect on this parasite. Against D. viviparus Fenbendazole, Mebendazole and Ivermectin were of equal, moderate-high effectiveness. No drug had a complete effect on the «arrested» larvae of D. viviparus. Fenthion had no effect at all. Fenbendazole and Ivermectin were both 100% effective against intestinal nematodes. Mebendazole was less effective and Fenthion had no effects. Ivermectin is considered to be the overall most effective anthelmintic in this test.En jamforande studie av effekten av fyra anthelmintika mot några betydelsesfulla parasiter hos ren.Abstract in Swedish / Sammandrag: Fyra antiparasitmedel har prôvats mot några av renens viktigaste parasiter, nàmligen hudkorm (Oedemagena tarandi), svalgkorm (Cephenemyia trompe), hjårnmask (Elaphostrongylus rangiferi) och lungmask (Dictyocaulus viviparus). Vidare har medlens effekt på mag- tarmnematoder (Trichostongylider) också noterats. De prôvade medicinerna var Fenthion (Bayer), Mebendazole (Leo/Janssen), Fenbendazole (Hoechst) och Ivermectin (Merck Sharp & Dohme). Mot hud- och svalgkorm var Ivermectin 100% effektivt medan for Fenthion effekten var 86 resp 100%. Effekten av Fen- och Mebendazole mot de båda parasiterna var inte signifikant. Mot hjårnmask noterades mycket hôg effekt av Mebendazole och aven Fenbendazole medan Ivermectin hade något såmre effekt med den valda doseringen. Fenthion hade ingen effekt på denna parasit. Mot lungmask visade Fenbendazole och Ivermectin god effekt medan Mebendazole visade något lagre effekt. Inget av preparaten hade dock fullgod verkan på de vilande inaktiva 5:te stadiets larverna av denna parasit. Fenthion hade ingen effekt. Mot mag-tarmnematoder var Fenbendazole och Ivermectin 100% effektiva medan Mebendazole hade en något làgre, delvis undertryckande effekt. Fenthion hade ingen effekt. Ivermectin får anses vara det allmånt sett effektivaste maskmedlet i denna undersokning.Vertailevatutkielma neljan loislaakeaineen vaikutuksesta muutamia tarkeita porojen loisia vastaan.Abstract in Finnish / Yhteenveto: On kokeiltu neljaa loislaakeainetta muutamia porojen tarkeinpia loisia vastaan, nimittain kurmua (Oedemagena tarandi), saulakkaa (Cephenemyia trompe), aivomatoa (Elaphostrongylus rangiferi) ja keuhkomatoa (Dictyocaulus viviparus). Edelleen on laakeaineiden vaikutus maha- ja suolistomatoihin (Trichostrongyliidit) myoskin pantu merkille. Kokeillut laakeaineet olivat Fenthion (Bayer), Mebendazole (Leo/Janssen), Fenbendazole (Hoechst) ja Ivermectin (Merck - Sharp and Dohme). Kurmua ja saulakkaa vastaan oli Ivermectin 100% tehokas, kun taas Fenthionin vaikutus oli toisessa 86 ja toisessa 100%. Fen- ja Mebendazolen vaikutus molempia loisia vastaan ei ollut merkittava. Mebendazolen ja myos Fenbendazolen vaikutus aivomatoa vastaan havaittiin hyvin korkeaksi, kun taas Ivermectinilla oli jonkin verran huonompi vaikutus valitulla annostuksella. Fenthionilla ei ollut mitaan vaikutusta tata loista vastaan. Keuhkomatoa vastaan osoitti Fenbendazole ja Ivermectin hyvan vaikutuksen, kun taas Mebendazolella oli jonkin verran heikompi vaikutus. Kuitenkaan ei millaan laakevalmisteista ollut taystehokasta vaikutusta taman loisen lepaaviin tehottomiin 5:asteen toukkiin. Fenthionilla ei ollut mitaan vaikutusta. Fenbendazole ja Ivermectin maha- ja suolistomatoja vastaan olivat 100% tehokkaita, kun taas Mebendazolella oli jonkin verran alhaisempi, osittain vaimentava vaikutus. Fenthionilla ei ollut mitaan vaikutusta