Enrichment of heavy metals and organic compounds in the surface microlayer of Narragansett Bay, Rhode Island

Concentrations of lead, iron, nickel, copper, fatty acids, hydrocarbons, and chlorinated hydrocarbons are enriched from 1.5 to 50 times in the top 100 to 150 micrometers of Narragansett Bay water relative to the bulk water 20 centimeters below the surface. Trace metal enrichment was observed in the particulate and organic fractions but not in the inorganic fraction. If these substances are concentrated in films only a few molecular layers thick on the water surface, the actual enrichment factor in the films may be well over 10(4), resulting in extremely high localized pollutant concentrations in the surface microlayer.     

Maximum benefit of a precise nitrogen application system for wheat

Research is ongoing to develop sensor-based systems to determine crop nitrogen needs. To be economic and to achieve wide adoption, a sensor-based site-specific application system must be sufficiently efficient to overcome both the cost disadvantage of dry and liquid sources of nitrogen relative to applications before planting of anhydrous ammonia and possible losses if weather prevents applications during the growing season. The objective of this study is to determine the expected maximum benefit of a precision N application system for winter wheat that senses and applies N to the growing crop in the spring relative to a uniform system that applies N before planting. An estimate of the maximum benefit would be useful to provide researchers with an upper bound on the cost of delivering an economically viable precision technology. Sixty five site-years of data from two dryland winter wheat nitrogen fertility experiments at experimental stations in the Southern Plains of the U.S.A. were used to estimate the expected returns from both a conventional uniform rate anhydrous ammonia (NH₃) application system before planting and a precise topdressing system to determine the value of the latter. For prices of $0.55 and $0.33 kg⁻¹ N for urea-ammonium nitrate (UAN) and NH₃, respectively, the maximum net value of a system of precise sensor-based nitrogen application for winter wheat was about $22–$31 ha⁻¹ depending upon location and assumptions regarding the existence of a plateau. However, for prices of $1.10 and $0.66 kg⁻¹ N for UAN and NH₃, respectively, the value was approximately $33 ha⁻¹. The benefit of precise N application is sensitive to both the absolute and relative prices of UAN and NH₃.This is journal paper AEJ-260 of the Oklahoma Agricultural Experiment Station, project H-2574.     

Spectroscopic Observation of the Formyl Cation in a Condensed Phase

The formyl cation, HCO+, has long been believed to be an important intermediate in the chemistry of carbon monoxide (CO) in acidic environments, but its spectroscopic observation in solution has been elusive. This species was generated by the reaction of CO with the liquid superacid hydrofluoric acid-antimony pentafluoride (HF-SbF5) under pressure and was observed by nuclear magnetic resonance and infrared spectroscopy. Equilibria between CO in the gas phase, CO dissolved in HF-SbF5, the SbF5 adduct of formyl fluoride, and HCO+ associated with several equilibrating anions of the type [SbxF5x+1]- are proposed to describe the system.     

Gene co-inheritance and gene transfer

Functional transfer of mitochondrial genes to the nucleus is very common in some taxa but entirely lacking in others. Current evolutionary theories to account for this variation predict that outcrossing, which allows escape from Muller's ratchet and faster spread of beneficial mutations, should favor gene transfer. We find that functional gene transfer is more common in selfing or clonal plants than in outcrossing plants, a pattern opposite to prediction. We suggest that reproductive modes, such as selfing and vegetative reproduction, conserve adaptive mitonuclear gene combinations, allowing functional transfer, whereas outcrossing prevents transfer by breaking up these combinations.     

Predatory Dinosaurs from the Sahara and Late Cretaceous Faunal Differentiation

Late Cretaceous (Cenomanian) fossils discovered in the Kem Kem region of Morocco include large predatory dinosaurs that inhabited Africa as it drifted into geographic isolation. One, represented by a skull approximately 1.6 meters in length, is an advanced allosauroid referable to the African genus Carcharodontosaurus. Another, represented by a partial skeleton with slender proportions, is a new basal coelurosaur closely resembling the Egyptian genus Bahariasaurus. Comparisons with Cretaceous theropods from other continents reveal a previously unrecognized global radiation of carcharodontosaurid predators. Substantial geographic differentiation of dinosaurian faunas in response to continental drift appears to have arisen abruptly at the beginning of the Late Cretaceous.