Influence of agronomic management of legume crops on soil accumulation with nitrate

Nitrate is known to accumulate under legume crops. The effects of legume crop, inoculation, row width, sowing rate, sowing date, and intra-cropping with wheat, on the amount and soil distribution of mineral N, residual soil water, crop biomass and crop N were studied at Wagga Wagga in south-east Australia. After removal of most of the above-ground plant material, the treatment effects on the biomass, N content, grain yield and grain N of wheat, established in the following season, were also measured. In a later experiment at Wagga, the recovery of 15N applied to the mid-row of lupin crops established at three row widths was estimated at crop maturity. At Condobolin, row width effects on the soil distribution of mineral N, biomass, N accumulation and N fixation of crop legumes and cereals, were determined. At physiological maturity, at Wagga Wagga, very little nitrate was left beneath cereals. Significantly more was left under legume crops, mostly below 30 cm of soil depth, and it was distributed differently depending on crop, inoculation, and sampling location. More nitrate was left under pea and faba than under lupin, and in response to inoculation. Mixing wheat with narrow-leaf lupin did not prevent nitrate accumulation in soil. For most of the legumes more nitrate was left in the mid-row than in the in-row; and more nitrate was left at the mid-row of lupin crops sown with wider rows. The additional nitrate left with wider rows increased the growth, N content, grain yield and protein of wheat established in the following season. 15N labelled nitrate applied mid-row was used less effectively by lupin as row width increased, in a dry season. At Condobolin, lupin established with wide rows used less soil nitrate than with narrower rows but maintained crop N by increased N fixation. In contrast, field pea maintained N demand by increasing nitrate uptake at intermediate row spacing. The study shows that the amount of nitrate accumulated in soil during legume cropping is susceptible to agronomic management, particularly crop selection, row width and inoculation; and that variation in the amount of this nitrate may carry forward to impact wheat production in the follow-on season.     

Synthesis,characterization and crystal structure of (cis-P,P′-diphenyl-1,4-diphospha-cyclohexane)molybdenum(0)tetracarbonyl

The preparation of the novel (cis-P,P′-diphenyl-1,4-diphospha-cyclohexane)molybdenum(0)tetracarbonyl complex is described. The spectral data and X-ray structure of the title complex are reported. The results of the crystallographic work show a distorted octahedral complex around the metal center, the first of its kind reported for the P,P′-diphenyl-1,4-diphospha-cyclohexane ligand.     

A novel hexagonal honeycomb K–Cr-oxalate anionic network with layers separated by a five-coordinated Cu(II)–pypn complex (pypn = N,N′-bis(2-pyridylmethyl)-1,3-propanediamine). Synthesis,characterisation, spectroscopy and crystal structure of {[KCr(C2O4)3][Cu(pypn)(H2O)](H2O)4}

A novel hexagonal-based honeycomb compound with overall formula {[KCr(C₂O₄)₃][Cu(pypn)(H₂O)](H₂O)₄} is reported in which pypn is with the tetradentate ligand (N,N′-bis(2-pyridylmethyl)-1,3-propanediamine). The [KCr(C₂O₄)₃]^2? moiety forms a hexagonal honeycomb structure, while the five-coordinated [Cu(pypn)(H₂O)]²⁺ moiety is located in between the layers, partly filling the holes in the cavities. The synthesis, X-ray crystal structure and some spectroscopic properties are presented. The coordination of Cr(III) is octahedral, with a CrO₆ chromophore, and the K⁺ ion is in a KO₆ environment (K–O distances vary from 2.36 to 2.48 ?). The [KCr(C₂O₄)₃]^2? layers have the K⁺ ions in a Λ conformation, while the Cr(III) ions in the Δ conformation. The geometry around the Cu(II) is five-coordinated with four nitrogens from the chelating pypn ligand in a plane and the apical position being occupied by the oxygen atom of the coordinating water molecule. The packing of the cationic and the anionic layers appears to be of special interest.     

A comparison of SWAT, HSPF and SHETRAN/GOPC for modelling phosphorus export from three catchments in Ireland

Recent extensive water quality surveys in Ireland revealed that diffuse phosphorus (P) pollution originating from agricultural land and transported by runoff and subsurface flows is the primary cause of the deterioration of surface water quality. P transport from land to water can be described by mathematical models that vary in modelling approach, complexity and scale (plot, field and catchment). Here, three mathematical models (soil water and analysis tools (SWAT), hydrological simulation program-FORTRAN (HSPF) and système hydrologique Européen TRANsport (SHETRAN)/grid oriented phosphorus component (GOPC)) of diffuse P pollution have been tested in three Irish catchments to explore their suitability in Irish conditions for future use in implementing the European Water Framework Directive. After calibrating the models, their daily flows and total phosphorus (TP) exports are compared and assessed. The HSPF model was the best at simulating the mean daily discharge while SWAT gave the best calibration results for daily TP loads. Annual TP exports for the three models and for two empirical models were compared with measured data. No single model is consistently better in estimating the annual TP export for all three catchments.     

Evaluation,modification and comparison of two rapid assays for cyanogens in cassava

Two rapid semi-quantitative assays for total cyanogens in cassava were evaluated. These were the well-known rapid picrate paper test, and a recently proposed rapid paper test involving the reagent tetra base (TB, 4,4′- methylenebis-(N, N-dimethylaniline)). A precise colorimetric assay was used as a control in the evaluative work. After primary evaluation, both assay methods underwent some modification regarding the interpretation of sample scores. As a result, the reliability of the picrate assay was greatly improved. The TB assay was modified in the interests of safety. Evaluation of this assay over a range of temperatures between 20 and 35°C showed no significant temperature effects upon performance when the new scoring interpretation system was used. The level of endogenous linamarase activity in the sample was found to be an influential factor in rapid assay performance. In a series of comparative trials in three distinct ecosystems, the newly modified picrate assay produced correct results in 68% of cases. This compared with 66% of results correct in the TB assay. It was observed that the TB assay performed more reliably with low cyanogen samples, whilst the picrate assay was more reliable with intermediate cyanogen samples.     

Do tricyclic responders have different brain laterality?

A previous study showed that depressed patients who improved with tricyclic antidepressant medication had dichotic complex tones test results suggesting right-hemisphere dysfunction relative to nonresponders and controls (G. E. Bruder et al., 1990). A new sample of 68 depressed patients completed dichotic consonant-vowel (CV) and complex tones (CT) tests and then were treated with imipramine or placebo. A significant Ear?×?Test?×?Treatment?×?Response interaction was accounted for by significantly poorer left-ear accuracy for CVs among imipramine responders compared with nonresponders, placebo responders, and controls. CV left-ear accuracy was also significantly greater among placebo responders than placebo nonresponders; and controls. The results only partially replicate the prior study in that evidence of right-hemisphere dysfunction in tricyclic responders was seen for the CV test but not the CT test. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

How small the contacts could be optimal for nanoscale organic transistors?

We report on a study seeking an optimized contact configuration for organic transistors that minimizes contact effects but maintains smallest contact size. We begin with the bulk access resistance in staggered transistors which results from the charge transport through the organic semiconductor film. Bulk access resistance is an intrinsic contributor to the contact resistance which has been little understood due to lack of a reliable study tool. In this work, we utilize the inner transported power inside the semiconductor film as a medium to investigate the contact resistance and the relevant contact effects. We examine the influences of the organic film thickness (t_SC), the channel length (L), the underlying charge transport and various organic semiconductor materials with variable carrier mobility. A roughly optimal contact length (L_C) of L_C0 ≈ 6t_SC is obtained. The results reveal that besides the device architecture the underlying charge transport should be also taken into account in designing organic transistors for practical application.     

Safety climate and the Theory of Planned Behavior: Towards the prediction of unsafe behavior

The present study is concerned with the human factors that contribute to violations in aviation maintenance. Much of our previous research in this area has been based on safety climate surveys and the analysis of relations among core dimensions of climate. In this study, we tap into mainstream psychological theory to help clarify the mechanisms underlying the links between climate and behavior. Specifically, we demonstrate the usefulness of Ajzen's (1991, 2001) Theory of Planned Behavior (TPB) to understanding violation behaviors in aircraft maintenance. A questionnaire was administered to 307 aircraft maintenance workers. Constructs measured by the survey included perceptions of management attitudes to safety, own attitudes to violations, intention to violate, group norms, workplace pressures, and violations. A model based on the TPB illustrated hypothetical connections among these variables. Path analyses using AMOS suggested some theoretically justifiable modifications to the model. Fit statistics of the revised model were excellent with intentions, group norms, and personal attitudes combining to explain 50% of the variance in self-reported violations. The model highlighted the importance of management attitudes and group norms as direct and indirect predictors of violation behavior. We conclude that the TPB is a useful tool for understanding the psychological background to the procedural violations so often associated with incidents and accidents.     

New optical material europium EDTA complex in polyvinyl pyrrolidone films with fluorescence enhanced by silver plasmons

In our search for efficient Luminescent Solar Concentrators (LSC) we have prepared polyvinyl pyrrolidone (PVP) films incorporated by ethylenediamine tetraacetic acid (EDTA) complex of europium and co-doped with silver nanoparticles (NPs). Steady state fluorescence was studied under weak and strong excitation. Dynamical study was performed by second harmonic of Nd laser. Under weak excitation the fluorescence of europium co-doped with silver plasmons increased by a factor of three and excited by continuous laser by a factor of 50. The lifetimes of films doped by the complex were 755 μs and co-doped with silver nanoparticles 946 μs. This is the first finding that the photon density accumulates the number of plasmons interacting with electronic states of europium increasing its transition probability resulting in the strong intensification of fluorescence. In dynamical measurements of lifetimes a single pulse does not provide enough energy to create such number of plasmons.