the results are published in the april issue of the journal acs nano.

the advance provides evidence to support a controversial idea, called multiple-exciton generation (meg), which theorizes that it is possible for an electron that has absorbed light energy, called an exciton, to transfer that energy to more than one electron, resulting in more electricity from the same amount of absorbed light.

robust, highly mobile amphibious robots have the potential to assist researchers in quickly gathering critical data in situations where it is difficult or inconvenient for humans to perform these tasks.

scientific assessment of the ecological effects that result from oil spills is currently difficult to obtain. the long-term effects of an oil spill can remain hidden in widespread, hard to reach locations after visual evidence has vanished from sight. the compact, nimble aquapod is equipped with a suite of sensors to sample specimens and collect data that make it well suited to deploy into remote areas.  

the study, conducted at carnegie mellon university, determined that although small battery pack vehicles still use some gasoline, they offer greater greenhouse gas reductions per dollar spent than large pack vehicles.

the results suggest that the automakers should focus on vehicles with shorter electrical ranges, rather than those that can travel greater distances on a single charge because they have larger batteries.

results of this work could affect government and corporate strategy for vehicle electrification and reduction of automobile-based greenhouse gas emissions. the findings could also help provide more cost-effective options for consumers interested in hybrid and plug-in vehicles.

the government has set a target of 1 million plug-in vehicles on the road by 2015 and currently provides incentives for automakers to increase battery pack size. a longstanding goal has been to increase the range of electric vehicles.

the study’s results suggest, however, that hybrid electric vehicles and plug-in vehicles with small battery packs may be better solutions. larger battery packs are expensive and underutilized when drivers travel distances shorter than the range of their battery packs. this means that on many trips drivers are effectively carrying around expensive dead weight.

a given level of resources can provide more small-pack vehicles than large-pack vehicles. in addition, small-pack autos would grant drivers higher utilization at a lower cost–one they are more likely to recoup over the life of the vehicle. finally, smaller packs could achieve greater greenhouse reductions per tax dollar and consumer dollar, especially if parallel efforts reduce harmful emissions from the electricity grid.

grinnell’s ninety-year-old maps, photographs and field notes provided a basis for locating his original survey sites along a transect that passed from the san joaquin valley through yosemite to mono lake, and covered an elevation range from near sea level to more than 10,000 feet. within the park, moritz’s team returned to sites from the valley floor to the mountain crest and collected animals in many of the same locations as grinnell. moritz’s team relied on live-animal traps; whereas grinnell’s original survey used lethal traps to collect animals. mathematical checks showed that the different collection techniques were not a problem in successfully comparing the two sets of data.

moritz’s team used the new survey results and grinnell’s original data to compare the ranges of 28 species of mammals. on average, the mammals had moved their ranges upward about 500 meters at the same time that the temperature in the area increased 3 degrees celsius. the species that were originally found at lower elevations tended to expand their ranges to higher elevations. species originally at higher elevations tended to contract their ranges as their minimum elevations shifted even higher. this suggests that species are already trying to adapt to a warmer climate. it also suggests that species that have historically lived at higher elevations may not have anywhere to go in the future as mountain tops experience temperature changes. further warming would lead to the extinction of many species that are adapted to cold, alpine conditions.

scientists believe abrupt changes in the atlantic meridonial overturning circulation, the dominant north-south ocean circulation current in the atlantic, caused the observed abrupt climate changes in the north atlantic. climate modelers from oregon state university have modeled an episode of abrupt climate change that shows remarkable agreement with observed concentrations of greenhouse gases. they concluded that ocean circulation changes were primarily responsible for driving co2 and nitrous oxide fluctuations during glacial periods on millennial time scales.

ultimately, the model’s agreement with ice core sample evidence lends credibility to the hypothesis that ocean circulation modulates variations in greenhouse gases. this knowledge may also help scientists postulate a solution for climate change.

researchers at texas a&m, missouri university of science and technology and the university of toronto have collaborated on another project that is also focused on learning from nature. the team is exploring how to capture the function of a natural system and use this to generate new design ideas. they have discovered that natural systems may be modeled functionally as if they were engineered systems. researchers can therefore design engineered systems by adapting solutions from natural systems. for example, they have studied the maneuverability of a housefly and captured the function and energy use of its wings, which can then be applied to improving the design of a micro-vehicle with flapping wings. however, in applying biologically-based design, it is critical to understand energy sources and flows.

by looking to nature for inspiration, engineers and designers can draw upon a multitude of design elements to solve design problems. both teams are discovering the underlying principles behind designs in nature and applying them to engineered designs with the goal of creating more environmentally friendly and energy efficient systems.

the new measurement technique may be useful for the detection of air toxins and also further our understanding of the health effects of atmospheric particles. insights gained could ultimately inform regulatory policy for managing air pollution and addressing its impact on global climate change.

a team of university of vermont researchers developed the technique, called near infrared laser desorption/ionization aerosol mass spectrometry, which can analyze trace levels of individual compounds within particles. the ability to measure oa chemical composition will lead to a better understanding of oa sources, as well as what controls their levels in the atmosphere.

aerosol mass spectrometry is widely used to analyze atmospheric aerosols, but usually cannot directly monitor the chemical composition of oa particles at their typical atmospheric concentrations. the nsf-funded innovation uses a low-energy, infrared laser to gently create ions of the organic compounds, keeping them intact and thereby giving results that are easier to interpret. the technique has demonstrated unprecedented sensitivity in detecting individual chemical compounds. this allows for analysis of the changes in aerosol composition as they occur in the atmosphere.

fluctuations in the npgo are driven by the same fundamental processes that control salinity and nutrient concentrations. in the california current system, the npgo particularly reflects changes in the winds that cause coastal upwelling, the process by which subsurface cold water that is rich in nutrients is brought up to the surface. these results strongly support the use of the npgo as the primary indicator of upwelling strength and nutrient fluxes, and, therefore, the potential for ecosystem change in the california current system region. changes in nutrient fluxes drive fluctuations in modeled chlorophyll concentration—an indicator of phytoplankton concentration—that are highly correlated to observed chlorophyll. the model simulations support the hypothesis that variations in phytoplankton biomass in the california current system region are primarily driven by changes in wind-driven upwelling correlated with the npgo. the npgo thus provides a strong indicator of changes in the mechanisms driving oceanic ecosystem dynamics.

this “bottom-up” forcing is consistent with previous fish catch data and satellite-derived chlorophyll concentration, and underscores the need to better understand the influences of physically forced nutrient fluxes on higher food-chain levels in the ocean. the researchers have also shown that the npgo pattern extends beyond the north pacific and is part of a global mode of climate variability that is evident in global sea-level trends and sea surface temperature. the amplification of the npgo variability found in observations and in model simulations of global warming scenarios implies that the npgo may play an increasingly important role in forcing global-scale decadal changes in marine ecosystems.