A cost-benefit analysis of hedgerow intercropping in the Philippine uplands using the SCUAF model

Soil erosion in the Philippine uplands is severe. Hedgerow intercropping is widely advocated as an effective means of controlling soil erosion from annual cropping systems in the uplands. However, few farmers adopt hedgerow intercropping even in areas where it has been vigorously promoted. This may be because farmers find hedgerow intercropping to be uneconomic compared to traditional methods of farming. This paper reports a cost-benefit analysis comparing the economic returns from traditional maize farming with those from hedgerow intercropping in an upland community with no past adoption of hedgerows. A simple erosion/productivity model, Soil Changes Under Agroforestry (SCUAF), is used to predict maize yields over 25 years. Economic data were collected through key informant surveys with experienced maize farmers in an upland community. Traditional methods of open-field farming of maize are economically attractive to farmers in the Philippine uplands. In the short term, establishment costs are a major disincentive to the adoption of hedgerow intercropping. In the long term, higher economic returns from hedgerow intercropping compared to open-field farming are realised, but these lie beyond farmers' limited planning horizons

Mechanically driven ATP synthesis by F-1-ATPase

ATP, the main biological energy currency, is synthesized from ADP and inorganic phosphate by ATP synthase in an energy-requiring reaction(1-3). The F-1 portion of ATP synthase, also known as F-1-ATPase, functions as a rotary molecular motor: in vitro its gamma-subunit rotates(4) against the surrounding alpha(3)beta(3) subunits(5), hydrolysing ATP in three separate catalytic sites on the beta-subunits. It is widely believed that reverse rotation of the gamma-subunit, driven by proton flow through the associated F-o portion of ATP synthase, leads to ATP synthesis in biological systems(1-3,6,7). Here we present direct evidence for the chemical synthesis of ATP driven by mechanical energy. We attached a magnetic bead to the gamma-subunit of isolated F-1 on a glass surface, and rotated the bead using electrical magnets. Rotation in the appropriate direction resulted in the appearance of ATP in the medium as detected by the luciferase-luciferin reaction. This shows that a vectorial force ( torque) working at one particular point on a protein machine can influence a chemical reaction occurring in physically remote catalytic sites, driving the reaction far from equilibrium

The sleep-deprived human brain

How does a lack of sleep affect our brains? In contrast to the benefits of sleep, frameworks exploring the impact of sleep loss are relatively lacking. Importantly, the effects of sleep deprivation (SD) do not simply reflect the absence of sleep and the benefits attributed to it; rather, they reflect the consequences of several additional factors, including extended wakefulness. With a focus on neuroimaging studies, we review the consequences of SD on attention and working memory, positive and negative emotion, and hippocampal learning. We explore how this evidence informs our mechanistic understanding of the known changes in cognition and emotion associated with SD, and the insights it provides regarding clinical conditions associated with sleep disruption