2,134 research outputs found

    Shoot organogenesis in leaf explants of Hydrangea macrophylla ‘Hyd1’ and assessing genetic stability of regenerants using ISSR markers

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    For the first time, an in vitro regeneration protocol of Hydrangea macrophylla 'Hyd1' was developed. Effects of different plant growth regulators (PGRs) on shoot regeneration were investigated jointly with selecting optimal basal media and cefotaxime concentrations. The highest frequency of shoot organogenesis (100%) and mean number of shoots per explant (2.7) were found on Gamborg B5 basal medium supplemented with 2.25 mg/l 6-benzyladenine (BA), 0.1 mg/l Indole-3-butyric acid (IBA), 100 mg/l cefotaxime and 30 g/l sucrose solidified by 7 g/l agar. Regenerated shoots were rooted by culturing on perlite plus half strength liquid B5 basal medium with 0.5 mg/l NAA. Rooted plantlets were transplanted to the greenhouse with 100% survival rate. Genetic stability of 32 plantlets (one mother plant and 31 regenerants) was assessed by 44 ISSR markers. Out of 44 ISSR markers, ten markers produced clear, reproducible bands with a mean of 5.9 bands per marker. The in vitro regeneration protocol is potentially useful for the genetic transformation of Hydrangea macrophylla 'Hyd1'

    Anomalous oxidation of Fe-Si alloys under a low oxygen pressure at 800 °C

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    The authors acknowledge financial support by NSFC of China under the research projects (Nos. 50971129 and 51371183).Abstract The oxidation of three Fe-xSi alloys (x = 5, 9, 13 at.%) under 10−20 atm O2 at 800 °C formed in all cases SiO2 layers. For Fe-5Si this layer broke down and healed up periodically forming an anomalous internal oxidation zone with spherical and net-shaped SiO2 particles. The SiO2 layer formed on the other two alloys spalled off due to the growth and thermal stress accumulated. The critical silicon content needed for its external oxidation on Fe-Si alloys calculated according to an extension of Wagner's theory under the present experimental conditions is significantly smaller than the experimental results.PostprintPeer reviewe

    Scheduling jobs with agreeable processing times and due dates on a single batch processing machine

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    AbstractIn this paper we study the problems of scheduling jobs with agreeable processing times and due dates on a single batch processing machine to minimize total tardiness, and weighted number of tardy jobs. We prove that the problem of minimizing total tardiness is NP-hard even if the machine capacity is two jobs and we develop a pseudo-polynomial-time algorithm for an NP-hard special case of this problem. We also develop a pseudo-polynomial-time algorithm for the NP-hard problem of minimizing weighted number of tardy jobs, which suggests that this problem cannot be strongly NP-hard unless P=NP

    Dynamic Response of Gradient Foams

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    The Voronoi-type density-gradient foams with three layers are numerically simulated, in order to study their dynamic response. The focus of the study is not only on the energy absorption and the distal stress of the gradient foam, but also the impact stress. The results obtained show that reduction of both the initial impact peak stress, and the early energy absorption of the gradient foam can be privided by reducing density of the first layer. The undesirable effect on the energy absorption can be alleviated by diminishing the thickness of the first layer. The difference between densities of the first two layers density should be limited to a certain range to avoid the peak stress appearing in the second layer. A weak distal layer can reduce the distal stress of the foam under high-velocity impact, while a high density gradient between the last two layers will result in the early increase of the distal stress under moderate-velocity impactС помощью численного метода исследованы динамические характеристики градиентных трехслойных пеноматериалов типа Вороного. Исследованы поглощение энергии, дистальные напряжения градиентного пеноматериала и напряжения при ударе. Установлено, что начальное максимальное напряжение при ударе и преждевременное поглощение энергии градиентного пеноматериала уменьшаются при низкой прочности первого слоя. Нежелательное влияние на поглощение энергии можно смягчить путем уменьшения толщины первого слоя. Различие между плотностью первых двух слоев необходимо контролировать в рамках предельного диапазона, чтобы избежать возникновения максимального напряжения во втором слое. Слабый дистальный слой может способствовать снижению дистального напряжения пеноматериала при высокой скорости удара, тогда как значительный градиент плотностей последних двух слоев приводит к преждевременному увеличению дистального напряжения при средней скорости удара.За допомогою числового методу досліджено динамічні характеристики градієнтних тришарових піноматеріалів типу Вороного. Досліджено поглинання енергії, дистальні напруження градієнтного піноматеріалу і напруження під час удару. Установлено,що початкове максимальне напруження під час удару і передчасне поглинання енергії градієнтного піноматеріалу зменшуються за низької міцності першого шару. Небажаний вплив на поглинання енергії можна зм’якшити шляхом зменшення товщини першого шару. Різницю між щільністю перших двох шарів необхідно контролювати у межах граничного діапазону, щоб запобігти виникненню максимального напруження у другому шарі. Слабкий дистальний шар може сприяти зниженню дистального напруження піноматеріалу за високої швидкості удару, в той час як значний градієнт щільностей останніх двох шарів призведе до передчасного збільшення дистального напруження при середній швидкості удару

    On the validity of Noah's giant clam Tridacna noae (Röding, 1798) and its synonymy with Ningaloo giant clam Tridacna ningaloo Penny & Willan, 2014

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    A new giant clam species, Tridacna ningaloo Penny & Willan, 2014 has been described from Ningaloo Reef, Western Australia. Meanwhile, it has been suggested that Noah's giant clam, Tridacna noae (Röding, 1798), previously resurrected from synonymy with T. maxima (Röding, 1798), is an invalid name. We assessed the validity of resurrecting T. noae and designating a neotype for it against the rules of zoological nomenclature and found no flaw in these acts. We then compared the genetic and morphological characters used in the respective diagnoses of T. noae and the newly-described Tridacna ningaloo. No difference was apparent between T. ningaloo and T. noae except, possibly, in mantle ornamentation patterns. In particular, the holotype of T. ningaloo possesses a mitochondrial DNA haplotype identical to T. noae. Thus, the hypothesis that T. ningaloo is a species distinct from T. noae was not supported by clear morphological evidence and it was contradicted by the available genetic evidence. Tridacna ningaloo should be regarded as a junior synonym of T. noae

    Seasonal timing for estimating carbon mitigation in revegetation of abandoned agricultural land with high spatial resolution remote sensing

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    Dryland salinity is a major land management issue globally, and results in the abandonment of farmland. Revegetation with halophytic shrub species such as Atriplex nummularia for carbon mitigation may be a viable option but to generate carbon credits ongoing monitoring and verification is required. This study investigated the utility of high-resolution airborne images (Digital Multi Spectral Imagery (DMSI)) obtained in two seasons to estimate carbon stocks at the plant- and stand-scale. Pixel-scale vegetation indices, sub-pixel fractional green vegetation cover for individual plants, and estimates of the fractional coverage of the grazing plants within entire plots, were extracted from the high-resolution images. Carbon stocks were correlated with both canopy coverage (R2: 0.76-0.89) and spectral-based vegetation indices (R2: 0.77-0.89) with or without the use of the near-infrared spectral band. Indices derived from the dry season image showed a stronger correlation with field measurements of carbon than those derived from the green season image. These results show that in semi-arid environments it is better to estimate saltbush biomass with remote sensing data in the dry season to exclude the effect of pasture, even without the refinement provided by a vegetation classification. The approach of using canopy cover to refine estimates of carbon yield has broader application in shrublands and woodlands

    The open-charm radiative and pionic decays of molecular charmonium Y(4274)

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    In this work, we investigate the decay widths and the line shapes of the open-charm radiative and pionic decays of Y(4274) with the DsDˉs0(2317)D_s\bar{D}_{s0}(2317) molecular charmonium assignment. Our calculation indicates that the decay widths of Y(4274)Ds+DsγY(4274)\to D^{+}_{s}D^{*-}_{s}\gamma and Y(4274)Ds+Dsπ0Y(4274)\to D^+_{s}D^-_{s}\pi^0 can reach up to 0.05 keV and 0.75 keV, respectively. In addition, the result of the line shape of the photon spectrum of Y(4274)Ds+DsγY(4274)\to D_s^+ {D}_s^{*-} \gamma shows that there exists a very sharp peak near the large end point of photon energy. The line shape of the pion spectrum of Y(4274)Ds+Dsπ0Y(4274)\to D_s^+ {D}_s^{*-} \pi^0 is similar to that of the pion spectrum of Y(4274)Ds+DsγY(4274)\to D_s^+ {D}_s^{*-} \gamma, where we also find a very sharp peak near the large end point of pion energy. According to our calculation, we suggest further experiments to carry out the search for the open-charm radiative and pionic decays of Y(4274).Comment: 7 pages, 6 figures, 1 table. Published versio

    Detection of herb-symptom associations from traditional chinese medicine clinical data

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    YesTraditional Chinese medicine (TCM) is an individualized medicine by observing the symptoms and signs (symptoms in brief) of patients. We aim to extract the meaningful herb-symptom relationships from large scale TCM clinical data. To investigate the correlations between symptoms and herbs held for patients, we use four clinical data sets collected from TCM outpatient clinical settings and calculate the similarities between patient pairs in terms of the herb constituents of their prescriptions and their manifesting symptoms by cosine measure. To address the large-scale multiple testing problems for the detection of herb-symptom associations and the dependence between herbs involving similar efficacies, we propose a network-based correlation analysis (NetCorrA) method to detect the herb-symptom associations. The results show that there are strong positive correlations between symptom similarity and herb similarity, which indicates that herb-symptom correspondence is a clinical principle adhered to by most TCM physicians. Furthermore, the NetCorrA method obtains meaningful herb-symptom associations and performs better than the chi-square correlation method by filtering the false positive associations. Symptoms play significant roles for the prescriptions of herb treatment. The herb-symptom correspondence principle indicates that clinical phenotypic targets (i.e., symptoms) of herbs exist and would be valuable for further investigations
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