Robot guards may patrol future frontiers

If scientist have their ways, then robot border guards would be patrolling the frontiers in the near future.Amid the ever-present angst over illegal immigration, cross-border terrorism and contraband smuggling,some nations are turning to novel broder-surveillance technologies, potentially backed up by robots.
According to a in New scientist, the idea is to scatter arrays of sensors in a border area in ways that give guards or robots plenty of time respond before their targets make good an escape.
The need to secure borders in evident across the globe, from India, which is constructing a 3.400Km, 3 meter- high barbed wire and concrete border wall to close itself off from Bangladesh, to Libya, where foot patrols are being augmented with new people sensing technologies.
liya has an agreement with the European Union to try to limit the flow of immigrants from sub-Saharan Africa traversing its borders before crossing the Mediterranean and entering Italy.
To help it enforce this deal,Libya is spending 300mn euros on technology for it calls a "large border security and control system",made by Selex Sistemi integrate,part of Italian aerospace firm finmeccania.

'Hot' Electrons in solar cells

Researchers at Boston college have observed the "hot electrons" effect in a solar cell for the first time and successfully harvested the elusive charges using ultra thin solar cells, opening a potential avenue to improved solar power efficiency.
when light is captured in solar cells, it generates free electrons in a range of energy states. But in order to snare these charges, the electrons must reach the bottom of the conduction band.
The problem has been that these highly energized "hot" electrons lose much of their energy to heat along the way.