Mechanisms of plant spindle formation

In eukaryotes, the formation of a bipolar spindle is necessary for the equal segregation of chromosomes to daughter cells. Chromosomes, microtubules and kinetochores all contribute to spindle morphogenesis and have important roles during mitosis. A unique property of flowering plant cells is that they entirely lack centrosomes, which in animals have a major role in spindle formation. The absence of these important structures suggests that plants have evolved novel mechanisms to assure chromosome segregation. In this review, we highlight some of the recent studies on plant mitosis and argue that plants utilize a variation of “spindle self-organization” that takes advantage of the early polarity of plant cells and accentuates the role of kinetochores in stabilizing the spindle midzone in prometaphase.     

The African Millennium Villages

We describe the concept, strategy, and initial results of the Millennium Villages Project and implications regarding sustainability and scalability. Our underlying hypothesis is that the interacting crises of agriculture, health, and infrastructure in rural Africa can be overcome through targeted public-sector investments to raise rural productivity and, thereby, to increased private-sector saving and investments. This is carried out by empowering impoverished communities with science-based interventions. Seventy-eight Millennium Villages have been initiated in 12 sites in 10 African countries, each representing a major agro-ecological zone. In early results, the research villages in Kenya, Ethiopia, and Malawi have reduced malaria prevalence, met caloric requirements, generated crop surpluses, enabled school feeding programs, and provided cash earnings for farm families.     

Impulsivity and adolescent substance use: rashly dismissed as "all-bad"?

The initial use of illicit drugs and alcohol typically occurs during adolescence. Individual differences in impulsivity and related constructs are consistently identified as key factors in the initiation and later problematic use of substances. Consequently, impulsivity is generally regarded as a negative trait; one that conveys only risk. However, what is often overlooked in addiction science is the positive role facets of trait impulsivity can play in everyday life and adaptive functioning. The following review aims to summarize recent advances in the psychobiology of impulsivity, including current perspectives on how it can convey risk for substance misuse. The review will also consider the importance of adolescence as a phase of life characterized by substantial neurodevelopment and natural increases in impulsivity. Uniquely, the review aims to reframe thinking on adolescent impulsivity to include the positive with the negative, and discuss how such thinking can benefit efforts for early intervention and future research.