8,273 research outputs found
Reply to Catalán : double-proton-transfer dynamics of photo-excited 7-azaindole dimers
The letter by Catalán (1) is concerned with the nature of double-proton transfer in dimers of 7-azaindole (7-AI), and the pertinent issue is whether or not the reaction is concerted. The subject is not new, and, for organic reactions, it has been discussed in the literature for decades. It is now understood that the concerted/consecutive mechanism has to be defined based on the timescale of the vibration motions and the family of coherent trajectories involved (ref. 2 and references therein). For double-proton transfer in isolated dimers, this timescale criterion has been invoked, and, as supported by a variety of time-resolved experiments in several groups and also by theory (ref. 3 and references therein), the conclusion is that the reaction is not concerted on the timescale of the vibrations involved; Catalán and some researchers (see ref. 3) assert that the two protons move in exact concert, maintaining the C_(2h) symmetry at all times
Nonchaotic Nonlinear Motion Visualized in Complex Nanostructures by Stereographic 4D Electron Microscopy
Direct electron imaging with sufficient time resolution is a powerful tool for visualizing the three-dimensional (3D) mechanical motion and resolving the four-dimensional (4D) trajectories of many different components of a nanomachine, e.g., a NEMS device. Here, we report a nanoscale nonchaotic motion of a nano- and microstructured NiTi shape memory alloy in 4D electron microscopy. A huge amplitude oscillatory mechanical motion following laser heating is observed repetitively, likened to a 3D motion of a conductor’s baton. By time-resolved 4D stereographic reconstruction of the motion, prominent vibrational frequencies (3.0, 3.8, 6.8, and 14.5 MHz) are fully characterized, showing evidence of nonlinear behavior. Moreover, it is found that a stress (fluence)−strain (displacement) profile shows nonlinear elasticity. The observed resonances of the nanostructure are reminiscent of classical molecular quasi-periodic behavior, but here both the amplitude and frequency of the motion are visualized using ultrafast electron microscopy
Effectiveness of liquid organic-nitrogen fertilizer in enhancing nutrients uptake and use efficiency in corn (Zea mays)
The ever increasing price of nitrogenous (N) fertilizers coupled with the deleterious effects of imbalanced N fertilizers on the environment necessitates the enhancement of N use efficiency of plants. The objectives of this study were to: (1) Evaluate the uptake of selected nutrients due to application of liquid organic-N fertilizers and (2) determine the efficiency of the formulated fertilizers in Zea mays cultivation in an acid soil. Liquid organic-N fertilizers with different sources of humic molecules were evaluated. The treatments were applied at 10 and 20 days after sowing (DAS) of corn. Plant and soil samples were collected at 54 DAS (tasseling stage) and analyzed for N, P, K, Ca, Mg and Na. The use of liquid organic-N fertilizer increased N content in leaf, stem and roots. The fertilizer with Fulvic acids (FA) increased N uptake and use efficiency. It also improved exchangeable Ca and Mg in soil solution. No significant difference was observered for soil exchangeable K. It can be concluded that the use of organic substances could enhance N uptake and N use efficiency of corn.Key words: Humic acids, fulvic acids, liquid fertilizers, nitrogen use efficiency, nutrient uptake, corn
Ammonia loss, ammonium and nitrate accumulation from mixing urea with zeolite and peat soil water under waterlogged condition
Ammonia loss from urea significantly hinders efficient use of urea in agriculture. In order to reduce ammonia loss and, at the same time, improve beneficial accumulation of soil exchangeable ammonium and nitrate for efficient utilization by plants, this laboratory study was conducted to determine the effect of mixing urea with zeolite and peat soil water on ammonia volatilization, soil exchangeable ammonium and available nitrate contents, compared with urea without additives under waterlogged condition. The soil used was Bekenu Series (Fine loamy, siliceous, isohyperthermic, red-yellow to yellow Tipik Tualemkuts). The mixtures significantly reduced ammonia loss by 25 to 38% compared with urea (straight urea, 46% N). All the mixtures of zeolite and peat soil water with urea significantly increased soil exchangeable ammonium (by 59 to 80 mg kg -1) and available nitrate (by 5 to 12 mg kg -1) contents. The temporary reduction of soil pH may have retarded urea hydrolysis. It could be possible to improve the efficiency of urea surface-applied to high value crops by addition of zeolite and peat soil water.Key words: Ammonia volatilization, peat soil water, exchangeable ammonium, available nitrate
Improving formulated nitrogen, phosphorus and potassium compound fertilizer using zeolite
Ammonia volatilization from urea and ammonium containing compound fertilizers cause higher cost of fertilization in agriculture. In this study, an incubation experiment was carried out to compare the effect of different ratios of compound fertilizer amended with clinoptilolite zeolite on NH3 volatilization, soil exchangeable NH4 and available NO3 contents on Bekenu Series (Tipik Tualemkuts) with surface-applied urea without additives. Treatments with zeolite significantly reduced NH3 loss when compared with urea without addictives. They also improved retention of exchangeable NH4 and NO3 and this was possible because zeolite favoured formation of ammonium and nitrate over ammonia. There is a potential for compound fertilizer with zeolite to improve nitrogen efficiency by lowering ammonia volatilization and increasing accumulation of exchangeable NH4 and NO3.Key words: Ammonia volatilization, compound fertilizers, clinoptilolite zeolite, soil exchangeable ammonium, available nitrate
Reducing ammonia volatilization from compound fertilizers amended with zeolite
Ammonia volatilization is a direct loss of available nitrogen in agriculture. The objective of this study was to determine the effect of amending NPK fertilizer with different rates of clinoptilolite zeolite on ammonia volatilization, soil exchangeable ammonium, and available nitrate. Seven treatments evaluated were: 250 g soil alone (T1), 3.28 g ammonium nitrate (AN) without additive (T2), 44.6 g 5:3:2 formulated fertilizer + 31.77 g zeolite (T3), 44.6 g 5:5:5 formulated fertilizer + 26.36 g zeolite (T4), 37.17 g 6:6:6 formulated fertilizer + 18.92 g zeolite (T5), 22.30 g 10:10:10 formulated fertilizer + 4.06 g zeolite (T6), and 14.87 g 15:15:15 commercial fertilizer (T7). The ammonia loss was measured using close-dynamic air flow system method. Soil pH, exchangeable ammonium and available nitrate at the end of this study were determined using standard procedures. The mixture of formulated fertilizer and zeolite significantly reduced ammonia volatilization. Zeolite in the formulated compound fertilizers did not significantly affect soil exchangeable ammonium and available nitrate. Amending N, P, and K compound fertilizer could minimize ammonia loss.Keywords: Ammonium nitrate, zeolite, ammonia volatilization, soil exchangeable ammonium, soil available nitrat
Smartphone apps for total hip replacement and total knee replacement surgery patients: a systematic review
Purpose: The aim of this study was to critically examine the content of smartphone apps produced for patients undergoing total hip replacement and total knee replacement surgery.Materials and methods: A systematic search was conducted across the five most popular smartphone app stores: iTunes; Google Play; Windows Mobile; Blackberry App World; and Nokia Ovi. Apps were identified for screening if they: targeted total hip replacement or total knee replacement patients; were free of charge; and were in English. App quality assessment was conducted independently by three reviewers using the Mobile App Rating Scale.Results: 15 apps met the inclusion criteria. On the 5-point Mobile App Rating Scale, the mean overall app quality score was 3.1. Within the Mobile App Rating Scale, the "Aesthetics" subscale had the most inconsistency across all apps, generating the highest and lowest mean scores (4.7 and 1, respectively). The "functionality" subscale had the highest mean score (3.8) among the four subscales, and the "information" subscale had the lowest mean score (2.7).Conclusion: This study highlights that despite a wide range of apps currently available to total hip replacement and total knee replacement patients, there is significant variability in their quality. Future efforts should be made to develop apps in partnership with patients, to improve the content, interactivity and relevance of apps.Implications for RehabilitationClinicians and rehabilitation professionals should consider that patients are using Smartphone apps to supplement their rehabilitation and be aware of currently available apps.Although some apps show promise, at present there is no one openly available app which is clinically recommended for rehabilitation use following total hip replacement and total knee replacement.Rehabilitation professionals tailor recovery programmes to individual patient needs following total hip replacement and total knee replacement, and future apps should also consider personal needs.We recommend that patients are involved in all stages of designing and testing future total hip replacement and total knee replacement rehabilitation apps
An HI study of the collisional ring galaxy NGC 922
We present new atomic hydrogen (HI) observations of the collisional ring
galaxy NGC 922 obtained using the Australia Telescope Compact Array. Our
observations reveal for the first time the vast extent of the HI disc of this
galaxy. The HI morphology and kinematics of NGC 922 show that this galaxy is
not the product of a simple drop-through interaction, but has a more complex
interaction history. The integrated HI flux density of NGC 922 from our
observations is 24.7 Jy km s, which is within the error of the flux
value obtained using the -m Parkes radio telescope. This flux density
translates to a total HI mass of M and corresponds to
an HI to total mass fraction (M/M) of approximately . The
gaseous structures of NGC 922 are more extended to the north and include an HI
tail that has a projected physical length of kpc. Gas warps are also
evident in the velocity field of NGC 922 and are more prominent on the
approaching and the western side of the disc. In comparison with a large sample
of star-forming galaxies in the local Universe, NGC 922 possesses a high gas
fraction relative to galaxies with a similar stellar mass of ~
M, and exhibits a high specific star formation rate.Comment: 11 pages, 8 figures, published in MNRA
Chirped imaging pulses in four-dimensional electron microscopy: femtosecond pulsed hole burning
The energy and time correlation, i.e. the chirp, of imaging electron pulses in dispersive propagation is measured by time-slicing (temporal hole burning) using photon-induced near-field electron microscopy. The chirp coefficient and the degree of correlation are obtained in addition to the duration of the electron pulse and its energy spread. Improving temporal and energy resolutions by time-slicing and energy-selection is discussed here and we explore their utility in imaging with time and energy resolutions below those of the generated ultrashort electron pulse. Potential applications for these imaging capabilities are discussed
Effects of crude humin and compost produced from selected waste on Zea mays growth, nutrient uptake and nutrient use efficiency
Waste from oil palm plantations, paddy fields, sawn timber and poultries are substantial. Inappropriate disposal of these wastes can cause environmental problems such as air and land pollutions. The objective of this study was to determine the effect of crude humin and compost produced from rice straw, rice husk, sawdust, and oil palm empty fruit bunch on growth, dry matter production, nutrient uptake and nutrient use efficiency of maize. Standard procedures were used to determine soil pH, total nitrogen, exchangeable ammonium, available nitrate, exchangeable phosphorus, cations, organic matter, total organic carbon and cation exchange capacity before and after planting. The plants were measured for diameter and height at tasselling stage prior to harvest. Dry matter production, nutrient uptake and nutrient use efficiency were also determined. Application of sawdust compost (T8) significantly increased maize plant diameter, height, dry matter production, and N, P and K uptake and use efficiency. It also reduced N, P and K based chemical fertilizer up to 90%. Application of humin and other selected waste composts (T6, T7 and T9) could be used as alternative for chemical fertilizers and their similar effects on maize plants.Keywords: Crude humin, Zea mays, nutrient uptake, nutrient use efficiencyAfrican Journal of Biotechnology Vol. 12(13), pp. 1500-150
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