Characteristics of Acacia mangium shoot apical meristems in natural and in vitro conditions in relation to heteroblasty

PDF version of the authors can be published in January 2013International audienceMorphological and histocytological characteristics of Acacia mangium shoot apical meristems (SAMs) were assessed in natural and in vitro conditions in relation to heteroblasty. In the natural environment, SAMs with a mature-phyllode morphology were much bigger, contained more cells with larger vacuolated area, or vacuome, and lower nucleoplasmic ratios than those from the juvenile type (Juv). In these latter, nuclei appeared more voluminous, evenly and lightly stained, with clearly distinguishable nucleolei and less abundant chromocenters. In vitro, where reversions from mature to juvenile morphological traits do occur unpredictably, heteroblasty was less obvious in the SAM characteristics examined. In vitro SAMs corresponding to the juvenile and mature types showed similarities with outdoor Juv SAMs, but could be distinguished from these latter by a much larger vacuome that might be induced by the culture conditions. These findings encourage pursuing the investigations at the chromatin and nucleolus level in SAM zones where heteroblasty-related differences have been detected

Thigh-length compression stockings and DVT after stroke

Controversy exists as to whether neoadjuvant chemotherapy improves survival in patients with invasive bladder cancer, despite randomised controlled trials of more than 3000 patients. We undertook a systematic review and meta-analysis to assess the effect of such treatment on survival in patients with this disease

Educational technology on a turning point: curriculum implementation in Flanders and challenges for schools

In this essay, we state that establishing technology curricula by national governments causes a shift in the policy actions of educational technology support: from a technical rationale with a main focus on funding and resources to a pedagogical rationale with a main focus on student competencies. We illustrate our point of view by describing the formal educational technology curriculum recently administered by the government in Flanders. This curriculum is written in terms of attainment targets and has clear implications on the nature of educational technology which is no longer dependent on teachers' individual efforts or willingness, but is becoming compulsory at the school level. Furthermore, we present two levers that facilitate the integration process of educational technology in general and the realization of technology curricula in particular. Technology coordinators should act more as curriculum managers and change agents, and schools should jointly establish a technology policy plan