16,138 research outputs found
Growth and nutrient uptake responses of ‘Seolhyang’ strawberry to various ratios of ammonium to nitrate nitrogen in nutrient solution culture using inert media
The effect of the variation of NH4+:NO3− ratios (meq/l: 0:100, 40:60, 50:50, 65:35 and 100:0) in the nutrient solution on strawberry (Fragaria × ananassa var Seolhyang) growth was evaluated. A mixture of large particle size (2 to 5 mm) and small particle size (smaller than 1 mm) of perlite was used as growing substrate and the nutrient solutions were applied once a week to the root substrate. The growth responses were determined 120 days after transplanting. The use of NO3− as the sole source of nitrogen in the nutrient solution resulted in the highest vegetative growth among the treatments tested. On the contrary, the exclusive use of NH4+ in the nutrient solution suppressed plant growth severely. The initial symptoms of ammonium toxicity appeared on the lower leaves, with the curling down of the old leaves. The margins turned brown and finally died. The introduction of the two nitrogen forms as the treatment ratio 60:40 (NH4+:NO3−) resulted in the optimal growth performance and nutrient uptake of this variety. The rate K/Ca+Mg=0.57, which was close to the best rate 0.67, allowed the optimal uptake of all nutrients. The data of the growth characteristics, nutrient content and electrical conductivity (EC) and pH were subjected to a polynomial regression analysis. The results show a high correlation between these data and the variation of NH4+:NO3− ratios. The values of the fresh and dry weight and N content of above-ground plant tissue to this variation were linear, with R2 coefficients of 0.95***, 0.94**, and 0.71*. The changes in the NO3− concentration in the petiole sap, EC and pH of the root substrate were quadratic, with a coefficients of R2= 0.99***, 0.98***, and 0.73*.Key words: Growth characteristics, NH4+: NO3− ratios, nutrient content, strawberry
Movement pattern components and mastery of an object control skill with error-reduced learning
Objectives: This paper reports the effects of error-reduced learning on movement components and mastery of overhand throwing in children with and without intellectual disability. Methods: Secondary data analysis was performed on two samples of children (typically developing, TD; intellectual disability, ID) who practiced overhand throwing in either an error-reduced (ER) or error-strewn (ES) condition. Movement pattern components were assessed using a sub-skill of Test of Gross Motor Development-2. Results: In TD participants, ER learners displayed improved follow-through while ES learners did not. Among children with ID, ER learners displayed greater improvements of hip/shoulder rotation and follow-through, than ES learners. Discriminant function analysis confirmed that changes in these components differentiated learning groups. Greater percentage of ER, compared to ES, participants progressed to mastery. Conclusions: With suppressed errors, the follow-through component of overhand throwing is likely to emerge, particularly in children with inferior abilities, and cognitive limitations. Error-reduced learning facilitates mastery
Successive spin-flop transitions of a Neel-type antiferromagnet Li2MnO3 single crystal with a honeycomb lattice
We have carried out high magnetic field studies of single-crystalline Li2MnO3, a honeycomb lattice antiferromagnet. Its magnetic phase diagram was mapped out using magnetization measurements at applied fields up to 35 T. Our results show that it undergoes two successive meta-magnetic transitions around 9 T fields applied perpendicular to the ab plane (along the c* axis). These phase transitions are completely absent in the magnetization measured with the field applied along the ab plane. In order to understand this magnetic phase diagram, we developed a mean-field model starting from the correct Neel-type magnetic structure, consistent with our single crystal neutron diffraction data at zero field. Our model calculations succeeded in explaining the two meta-magnetic transitions that arise when Li2MnO3 enters two different spin-flop phases from the zero field Neel phase.open1187Nsciescopu
Timing of drotrecogin alfa (activated) treatment in severe sepsis
The effect of the timing of drotrecogin alfa (activated) (DrotAA) treatment on the outcome of severe sepsis was recently evaluated, using the integrated clinical trial database INDEPTH. The evaluation demonstrated an association between earlier treatment (i.e. treatment within 24 hours of the appearance of first organ dysfunction) and lower patient mortality [1]. We assessed the timing of DrotAA treatment in our own (mixed) intensive care unit over a 3-year period. We selected all patients treated with commercial DrotAA since its availability in The Netherlands. Patients were treated with DrotAA according to the national guidelines [2]. As the results presented in Table 1 show, patients treated within 24 hours were younger and more often had pneumosepsis (45 % versus 9%, P = 0.03), which was due t
TeV scale mirage mediation in NMSSM
We study the next-to-minimal supersymmetric standard model. We consider soft
supersymmetry breaking parameters, which are induced by the mirage mediation
mechanism of supersymmetry breaking. We concentrate on the mirage mediation,
where the so-called mirage scale is the TeV scale. In this scenario, we can
realize the up-type Higgs soft mass of O(200) GeV, while other masses such as
gaugino masses and stop masses are heavy such as 1 TeV or more. Cancellation
between the effective \mu-term and the down-type Higgs soft mass ameliorates
the fine-tuning in the electroweak symmetry breaking even for \mu=O(500) GeV.
The mixing between the doublet and singlet Higgs bosons is suppressed by
(\lambda/\kappa)/tan\beta. Then the lightest doublet Higgs mass naturally
reaches 125 GeV lifted by the new quartic coupling. The higgsino and singlino
are light and their linear combination is the lightest superparticle.Comment: 24 pages, 24 figures, Numerical analysis is replaced with the version
calculated by NMSSMTools. Comments and references are added on the suppressed
doublet-singlet mixing and cases in which the 125 GeV boson is the 2nd
lightest CP-even scalar. The version accepted by JHE
Power-Law Distributions in a Two-sided Market and Net Neutrality
"Net neutrality" often refers to the policy dictating that an Internet
service provider (ISP) cannot charge content providers (CPs) for delivering
their content to consumers. Many past quantitative models designed to determine
whether net neutrality is a good idea have been rather equivocal in their
conclusions. Here we propose a very simple two-sided market model, in which the
types of the consumers and the CPs are {\em power-law distributed} --- a kind
of distribution known to often arise precisely in connection with
Internet-related phenomena. We derive mostly analytical, closed-form results
for several regimes: (a) Net neutrality, (b) social optimum, (c) maximum
revenue by the ISP, or (d) maximum ISP revenue under quality differentiation.
One unexpected conclusion is that (a) and (b) will differ significantly, unless
average CP productivity is very high
GaN micro-light-emitting diode arrays with monolithically integrated sapphire microlenses
A microdisk light emitting diode (micro-LED) with a monolithically integrated microlens array was demonstrated. The capability of the lenses in concentrating light emitted from microdisk LEDs was also demonstrated. The focal lengths of the microlenses were determined to be around 44 νm. The emission pattern of the LED emitters was found to be altered by the optical properties of the microlenses. The light emitted by the hybrid device was also found to be less divergent than a broad-area device.published_or_final_versio
Inhibition of class I histone deacetylases by romidepsin potently induces Epstein-Barr virus lytic cycle and mediates enhanced cell death with ganciclovir
Pan-histone deacetylase (HDAC) inhibitors, which inhibit 11 HDAC isoforms, are widely used to induce Epstein-Barr virus (EBV) lytic cycle in EBV-associated cancers in vitro and in clinical trials. Here, we hypothesized that inhibition of one or several specific HDAC isoforms by selective HDAC inhibitors could potently induce EBV lytic cycle in EBV-associated malignancies such as nasopharyngeal carcinoma (NPC) and gastric carcinoma (GC). We found that inhibition of class I HDACs, particularly HDAC-1, -2 and -3, was sufficient to induce EBV lytic cycle in NPC and GC cells in vitro and in vivo. Among a panel of selective HDAC inhibitors, the FDA-approved HDAC inhibitor romidepsin was found to be the most potent lytic inducer, which could activate EBV lytic cycle at ∼0.5 to 5 nM (versus ∼800 nM achievable concentration in patients' plasma) in more than 75% of cells. Upregulation of p21WAF1 , which is negatively regulated by class I HDACs, was observed before the induction of EBV lytic cycle. The upregulation of p21WAF1 and induction of lytic cycle were abrogated by a specific inhibitor of PKC-δ but not the inhibitors of PI3K, MEK, p38 MAPK, JNK or ATM pathways. Interestingly, inhibition of HDAC-1, -2 and -3 by romidepsin or shRNA knockdown could confer susceptibility of EBV-positive epithelial cells to the treatment with ganciclovir (GCV). In conclusion, we demonstrated that inhibition of class I HDACs by romidepsin could potently induce EBV lytic cycle and mediate enhanced cell death with GCV, suggesting potential application of romidepsin for the treatment of EBV-associated cancers.postprin
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