Internal migration and ethnic division: the case of Palmas,Brazil

Starting from the observation that Brazilian history has led to the development of a very distinct system of race relations, this paper focuses on the (re)creation of ethnic divisions in a new city, Palmas, the capital of the Brazilian state Tocantins. Because the city was only founded in 1990, internal migration has heavily influenced the composition of the city’s population. The research shows that residential proximity and interaction between whites and non‐whites is largely limited to the poor neighbourhoods of the city. Subtle racism continues to exist, deriving from a way of thinking that naturalises the racial hierarchy. The absence of clearly defined racial categories and the centrality of miscegenation to the Brazilian identity complicate the further dismantling of this racist culture.     

Structural assimilation in young first-, second- and third-generation migrants in Flanders

Assimilation theory assumes that differences between migrants and non-migrants disappear over generations. We report on a Flemish survey study conducted with young first- (G1), second- (G2) and third- (G3) generation migrants (n?=?1,587). The results showed that G1 and G2 had lower chances of being in educational tracks preparing for higher education than non-migrants. Further, G1 and G3 migrants with a background in the oldest fifteen members of the European Union (EU15) and G1 and G2 adolescents of non-EU15 migrants ran a higher risk of being delayed in their educational trajectories. All three generations of non-EU15 migrants had lower expectations of finding a job than non-migrants. Whereas socio-economic status could explain almost all of the differences for EU15 migrants, it could not for non-EU15 migrants. This leads to the hypothesis that visible differences and distinctive names lead to assumptions about ethnic, cultural and religious affiliations that are associated with discrimination.     

Activity-stimulating phenomena caused by field-disturbance in the use of pitfall-traps

Summary The influence of several mechanical field disturbances, when using pitfall-traps for activity determinations, is analysed. The disturbances result in higher catches of surface-dwelling Collembola; the animals being stimulated to higher locomotory activity.The disturbance by walking in the field results in a multiple of the control catch. This effect lasts for about 1 hour.The digging-in effect lasts for about two days but more or less different for the various species. The cause is sought in the CO₂ production in the soil, which is considerable after soil disturbances. The reaction of Collembola to rather high CO₂ concentrations in the air results in an increase of the locomotory activity.Another interpretation, namely attraction to CO₂ sources, could not be demonstrated.

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Zusammenfassung Der Einfluß verschiedener mechanischer Störungen im Feld bei der Anwendung der Fallenfangmethode wurde analysiert. Die Störungen stimulieren die Tiere zu größerer lokomotorischer Aktivität, wodurch sich höhere Fangtotale von epedaphischen Collembolen ergeben.Die Störung, welche durch vielfältiges Herumlaufen im Fangterrain entsteht, ergibt Fangtotale, die um ein Vielfaches höher sind als die Kontrollfänge. Dieser Effekt hält eine Stunde an.Eine andere Störung entsteht durch das Eingraben der Fallen. Es resultiert ebenfalls in eine höhere Anzahl gefangener Tiere. Dieser Effekt aber dauert etwa zwei Tage. Die Ursache liegt vermutlich in der Zunahme der CO₂-Produktion im Boden als Folge des Eingrabens. Erhöhte CO₂-Konzentration in der Luft resultiert tatsächlich in einer Zunahme der lokomotorischen Aktivität.Attraktion durch die CO₂-Quelle konnte nicht nachgewiesen werden.

     

Successful in vitro fertilization and generation of transgenics in Black and Tan Brachyury (BTBR) mice

The Black and Tan Brachyury (BTBR) mouse strain is a valuable model for the study of long-term complications from obesity-induced type 2 diabetes mellitus and autism spectrum disorder. Due to technical difficulties with assisted reproduction, genetically modified animals on this background have previously been generated through extensive backcrossing, which is expensive and time-consuming. We successfully generated two separate transgenic mouse lines after direct zygote microinjection into this background strain. Additionally, we developed in vitro fertilization (IVF) methods for the BTBR mouse. We found low rates of fertilization and implantation in this strain, and identified the BTBR oocyte as the primary culprit of low success with BTBR IVF. We achieved an increase in live born pups from 5.9 to 35.6 % with IVF in the BTBR strain by use of BTBR females at a younger age (18–25 days), collection of oocytes 15–17 h after superovulation, and the use of supplemented fertilization media. This method eliminates the need for time consuming assisted embryo manipulations that are otherwise required for success with BTBR oocytes. This advancement provides an exciting opportunity to directly generate BTBR transgenics and gene-edited mice using both traditional and emerging genomic editing techniques, such as CRISPR/Cas9. These methods also allow effective colony preservation and rederivation with these strains. To our knowledge, this is the first report describing embryo manipulations in BTBR mice.