[1] High density carbonate rhizoliths were found from a loess-paleosol succession from the late Wisconsin period (21–11 ka) in Illinois. Their morphology shows that they formed in a close contact with living and decomposing roots, suggesting a root/microbial respiration origin. Carbon (dC) and oxygen (dO) isotopic analyses were performed on 36 and 37 individual rhizoliths of two separate 10 cm ...

As global warming has lengthened the active seasons of many species, we need a framework for predicting how advances in phenology shape the life history and the resulting fitness of organisms. Using an individual-based model, we show how warming differently affects annual cycles of development, growth, reproduction and activity in a group of North American lizards. Populations in cold regions c...

[1] Arctic Oscillation (AO) changes are inferred from a treering reconstruction of a warm-season temperature index. The reconstruction covers AD 1650–1975 and is based largely on chronologies from circumpolar-Arctic and circum-North Atlantic areas. It accounts for 48% of the variance in the instrumental AO record from 1900 to 1975, verifies using independent data, and exhibits its largest varia...

Ozone uptake was studied in a pine forest in Tenerife, Canary Islands, an ecotone with strong seasonal changes in climate. Ambient ozone concentration showed a pronounced seasonal course with high concentrations during the dry and warm period and low concentrations during the wet and cold season. Ozone uptake by contrast showed no clear seasonal trend. This is because canopy conductance signifi...

Using long-term (1948–1996) pan evaporation measurements, a 6% increase in warm-season (May–October) actual evapotranspiration (ET ) is computed over the conterminous United States between 1949 and 1996 via the complementary hypothesis. This predicted increase in ET is in agreement with the measured precipitation increase for the same period if long-term wet-surface ET is assumed to be constant...

Switchgrass is a warm-season perennial grass native to much of the United States. Over the last few years, switchgrass has received renewed interest as a renewable fuel source, since it produces large amounts of cellulose that can be digested and converted to ethanol. The high yields and environmental adaptability of switchgrass make it an excellent choice for biofuel feedstock production. Whil...

[1] Arctic Oscillation (AO) changes are inferred from a treering reconstruction of a warm-season temperature index. The reconstruction covers AD 1650–1975 and is based largely on chronologies from circumpolar-Arctic and circum-North Atlantic areas. It accounts for 48% of the variance in the instrumental AO record from 1900 to 1975, verifies using independent data, and exhibits its largest varia...

BACKGROUND This study's aim was to design and validate a semi-quantitative food frequency questionnaire (FFQ) for assessment of fruits and vegetables (FV) consumption in adults of Isfahan by comparing the FFQ with dietary reference method and blood plasma levels of beta-carotene, vitamin C, and retinol. METHODS This validation study was performed on 123 healthy adults of Isfahan. FV intake wa...

BACKGROUND Controversy remains regarding the relationship between ambient ozone and mortality worldwide. In mainland China, the largest developing country, there has been no prior study investigating the acute effect of O3 on death risk. Given the changes in types of air pollution from conventional coal combustion to the mixed coal combustion/motor vehicle emissions in China's large cities, it ...

Grazing lands in warm-temperate and subtropical North America have become less diverse. Pastures are typically grass monocultures, while rangelands are generally managed for the grass components. Overstocking, selective herbicides, fire exclusion and heavy rates of nitrogen fertilizer have contributed to near exclusion of native, warm-season legumes. The simplicity of managing grass monoculture...