Separating nitrogen fertilizer and irrigation water application in an alternating furrow irrigation system for maize production

The efficient use of water and nitrogen represents a primary concern to agricultural production in Northwest China. A 2-year field experiment was conducted to assess the separation of nitrogen (N) fertilizer and irrigation water with alternating furrow irrigation (SNWAFI) in a maize (Zea mays L.) production system. Irrigation water use efficiency and nitrogen use efficiency with SNWAFI were generally greater than with conventional irrigation and fertilization (CIF). Response surfaces indicated that maximum maize yields were obtained with 238 kg urea-N ha^?1 and 106 mm irrigation water in 2008 and 244 kg urea-N ha^?1 and 95 mm of irrigation water in 2009. When the predicted yields were highest (6,384 and 6,549 kg ha^?1), water use efficiency, N uptake, and N use efficiency were greater with SNWAFI than CIF. Conversely, soil NO₃–N change during maize growing season decreased with SNWAFI compared CIF. With SNWAFI, optimizing irrigation water and N fertilizer rates can maximize yield, save irrigation water, and reduce N leaching.     

STRUCTURAL CHARACTERIZATION OF SOLID n-PARAFFIN COMPONENTS DERIVED FROM MUKTA CRUDE OIL

ABSTRACT

The total solid paraffins (boiling 270°C+) separated from Mukta crude by urea adduction and its narrow fractions were analysed for their structural composition by proton NMR, infrared spectroscopy and gas chromatography. It has been observed that CH2/CH3 ratio in these samples varies from 7·9 to 13·8 while their average carbon number ranges from 17 to 29·6. The CH₂/CH₃ ratio and chain length of paraffins increases with increase in boiling range of the fractions.     

Mushroom Hunting by Using Bioinformatics: Application of a Predictive Framework Facilitates the Selective Identification of Sesquiterpene Synthases in Basidiomycota

The Basidiomycota fungi represent a diverse source of natural products, particularly the sesquiterpenoids. Recently, genome sequencing, genome mining, and the subsequent discovery of a suite of sesquiterpene synthases in Omphalotus olearius was described. A predictive framework was developed to facilitate the discovery of sesquiterpene synthases in Basidiomycota. Phylogenetic analyses indicated a conservation of both sequence and initial cyclization mechanisms used. Here, the first robust application of this predictive framework is reported. It was used to selectively identify sesquiterpene synthases that follow 1,6‐, 1,10‐, and 1,11‐cyclization mechanisms in the crust fungus Stereum hirsutum. The successful identification and characterization of a 1,6‐ and a 1,10‐cyclizing sesquiterpene synthase, as well as three 1,11‐cyclizing Δ⁶‐protoilludene synthases, is described. This study verifies the accuracy and utility of the predictive framework as a roadmap for the discovery of specific sesquiterpene synthases from Basidiomycota, and thus represents an important step forward in natural product discovery.     

Alleviating artifacts in 1H MRI thermometry by single scan spatiotemporal encoding

Objective

Recent years have seen an increased interest in combining MRI thermometry with devices capable of destroying malignancies by heat ablation. Expected from the MR protocols are accurate and fast thermal characterizations, providing real time feedback on restricted tissue volumes and/or rapidly moving organs like liver. This article explores the potential advantages of relying on spatiotemporally encoded (SPEN) sequences for retrieving real-time thermometric images based on the water’s proton resonance frequency (PRF) shifts.

Materials and methods

Hybrid spatiotemporal/k-space encoding single-scan MRI experiments were implemented on animal and human scanners, and their abilities to deliver single- and multi-slice real-time thermometric measurements based on PRF-derived phase maps in phantoms and in vivo, were compared against echo planar imaging (EPI) and gradient-echo counterparts.

Results

Under comparable acquisition conditions, SPEN exhibited advantages vis-à-vis EPI in terms of dealing with inhomogeneous magnetic field distortions, with shifts arising due to changes in the central frequency offsets, with PRF distributions, and for zooming into restricted fields-of-view without special pulse sequence provisions.

Conclusion

This work confirms the ability of SPEN sequences, particularly when implemented under fully-refocused conditions, to exploit their built-in robustness to shift- and field-derived inhomogeneities for monitoring thermal changes in real-time under in vitro and in vivo conditions.     

Selective Deflection and Localization of Flowing Aerosols onto a Substrate

Pulsed airflow cued by the fluorescence spectrum of a particular aerosol can be used to distinguish and deflect particles of biological origin out of an aerosol stream, permitting concentration of these particles for subsequent analysis (Pan et al. 2004 Pan, Y. L., Boutou, V., Bottiger, J. R., Zhang, S. S., Wolf, J. P. and Chang, R. K. 2004. A Puff of Air Sorts Bioaerosols for Pathogen Identification. Aerosol Sci. Technol., 38: 598–602. [CROSSREF][CSA][Taylor & Francis Online], [Web of Science ®] , [Google Scholar]). However, these high velocity pulses of air have an inherent tendency to scatter particles, confounding efforts to concentrate these deflected particles for analysis. The ability to concentrate large numbers of biological particles into a small area on a collection substrate is particularly important for more species-specific techniques such as Raman and FTIR (Fourier Transform Infra-Red) spectroscopy, which require long integration times due to their weak signal strength. In the present work, a simple method is developed for deflecting and localizing particles after classification by a pulsed airflow. The concept is both modeled and experimentally tested. A specially designed funnel is used to localize the scattered particles onto an area of substrate as small as 1 mm in diameter. Computational fluid dynamics simulations were performed to investigate the interaction of the pulsed airflow with the deflected particles and the localizing funnel, in order to gain insight into design parameters and operating conditions that affect the efficiency of this technique. The results show that the combination of pulsed airflow with a localizing funnel effectively deflects and localizes the concentrated bioaerosol onto a small area of substrate or an opening of a microfluidic cell.     

Germany's solar cell promotion: Dark clouds on the horizon

This article demonstrates that the large feed-in tariffs currently guaranteed for solar electricity in Germany constitute a subsidization regime that threatens to reach a level comparable to that of German hard coal production, a notoriously outstanding example of misguided political intervention. Yet, as a consequence of the coexistence of the German Renewable Energy Sources Act (EEG) and the EU Emissions Trading Scheme (ETS), the increased use of renewable energy technologies does not imply any additional emission reductions beyond those already achieved by ETS alone. Similarly disappointing is the net employment balance, which is likely to be negative if one takes into account the opportunity cost of this form of solar photovoltaic (PV) support. Along the lines of the international energy agency [IEA, 2007. Energy policies of IEA countries: Germany, 2007 review. International Energy Agency, OECD, Paris, p. 77], we recommend the immediate and drastic reduction of the magnitude of the feed-in tariffs granted for solar-based electricity. Ultimately, producing electricity on this basis is among the most expensive greenhouse gas abatement options.     

On the Quaternary System Ti-Fe-Ni-Al

The homogeneity ranges of the Laves phases and phase relations concerning the Laves phases in the quaternary system Ti-Fe-Ni-Al at 900 °C were defined by x-ray powder diffraction (XPD) data and electron probe microanalysis (EPMA). Although at higher temperatures the Laves phase forms a continuous solid solution, two separate homogeneity fields of TiFe₂-based (denoted by λ_Fe) and Ti(TiNiAl)₂-based (denoted by λ_Ni) Laves phases appear at 900 °C. The relative locations of Laves phases, G phase, Heusler phase, and CsCl-type phase as well as the associated tie-tetrahedra were experimentally established in the quaternary for 900 °C and presented in three-dimensional (3D) view. Furthermore, a partial isothermal section TiFe₂-TiAl₂-TiNi₂ was constructed, and a connectivity scheme, derived for equilibria involving Laves phases in the Ti-Fe-Ni-Al quaternary system at 900 °C was derived. As a characteristic feature of the quaternary phase diagram, the solid solubility of fourth elements in both the TiFe₂-based and Ti(NiAl)₂-based Laves phases is limited at 900 °C and is dependent on the ternary Laves phase composition. A maximum solubility of about 8 at.% Ni is reached for composition Ti_33.3Fe_33.3Al_33.4. Structural details have been evaluated from powder x-ray and neutron diffraction data for (i) the Ti-Fe-Ni ternary and the Ti-Fe-Ni-Al quaternary Laves phases (MgZn₂-type, space group: P6₃/mmc) and (ii) the quaternary G phase. Atom site occupation behavior for all phases from the quaternary system corresponds to that of the ternary systems. For the quaternary Laves phase, Ti occupies the 4f site and additional Ti (for compositions higher than 33.3 at.%Ti) preferably enters the 6h site. Aluminum and (Fe,Ni) share the 6h and the 2a sites. The compositional dependence of unit cell dimensions, atomic coordinates, and interatomic distances for the Laves phases from the quaternary system is discussed. For the quaternary cubic G phase, a centrosymmetric as well as a noncentrosymmetric variety was observed depending on the composition: from combined x-ray and neutron powder diffraction measurements Ti_33.33Fe_13.33Ni_10.67Al_42.67 was found to adopt the lower symmetry with space group .