388 research outputs found
Flue-cured tobacco and Cl rates : implications on yield, quality, and nutrient concentration
The increase in flue-cured tobacco (Nicotiana tabacumL.) yields in recent decadesdue to genetic improvements of new cultivars and management technologies mayincrease the plant demand for Cl, and the increased dry mass may dilute Cl concentra-tion, thereby reducing negative effects. This study evaluated the effect of increasingdoses of Cl on tobacco production, quality, and chemical composition of leaves, infour growing environments located at research stations where flue-cured tobacco isproduced in North Carolina. The treatments consisted of 11 rates of Cl (0, 11, 22,34, 45, 56, 67, 78, 90, 101, and 112 kg haâ1) in each growing environment, with fourreplications in a randomized complete block design. The yield and visual quality,total alkaloids, and reducing sugars concentrations of cured leaf were determined.In addition, the concentration of selected nutrients (N, P, K, Ca, Mg, S, and Cl) andnitrate (NO3â) in tobacco leaves was measured in five different periods. Rates of Clup to 112 kg haâ1did not reduce the productivity or quality of flue-cured tobaccoin any environment. The Cl rate required to reach the threshold of 1.0% Cl contentin cured leaf was site-specific, being surpassed even in the control treatment at onelocation, or with Cl rates higher than 34 and 90 kg haâ1in two environments. Inone environment, the Cl rates increased tobacco yield, probably due the direct effectof Cl as a nutrient. Although the increasing Cl rates increased the reducing sugarsconcentration, visual quality was not attenuated
Germ plasm in Eleutherodactylus coqui, a direct developing frog with large eggs
<p>Abstract</p> <p>Background</p> <p>RNAs for embryo patterning and for germ cell specification are localized to the vegetal cortex of the oocyte of <it>Xenopus laevis</it>. In oocytes of the direct developing frog <it>Eleutherodactylus coqui</it>, orthologous RNAs for patterning are not localized, raising the question as to whether RNAs and other components of germ plasm are localized in this species.</p> <p>Methods</p> <p>To identify germ plasm, <it>E. coqui </it>embryos were stained with DiOC<sub>6</sub>(3) or examined by <it>in situ </it>hybridization for <it>dazl </it>and <it>DEADSouth </it>RNAs. The cDNAs for the <it>E. coqui </it>orthologues were cloned by RT-PCR using degenerate primers. To examine activity of the <it>E. coqui </it>orthologues, RNAs, made from constructs of their 3'UTRs with <it>mCherry</it>, were injected into <it>X. laevis </it>embryos.</p> <p>Results</p> <p>Both DiOC<sub>6</sub>(3) and <it>dazl </it>and <it>DEADSouth in situs </it>identified many small islands at the vegetal surface of cleaving <it>E. coqui </it>embryos, indicative of germ plasm. <it>Dazl </it>was also expressed in primordial germ cells in the genital ridge. The 3'UTRs of <it>E. coqui dazl </it>and <it>DEADSouth </it>directed primordial germ cell specific protein synthesis in <it>X. laevis</it>.</p> <p>Conclusions</p> <p><it>E. coqui </it>utilizes germ plasm with RNAs localized to the vegetal cortex to specify primordial germ cells. The large number of germ plasm islands suggests that an increase in the amount of germ plasm was important in the evolution of the large <it>E. coqui </it>egg.</p
The Lantern Vol. 70, No. 1, Fall 2002
âą (For Z) âą Little Sister âą Eulogy to Her Son, Dead at 22 âą Tuesday âą 7 Couplets for Drawing Genevieve âą Diner Reflection âą We Swam. We Made Sand Castles. âą His Lips Were Figure Fitting âą Public Transportation âą Pop Culture âą Running the Ridge âą Like a Sunflower âą Snooze âą Match âą Behavioral Correctional Facility of Santa Fe... âą The Cellarhttps://digitalcommons.ursinus.edu/lantern/1161/thumbnail.jp
Aquilegia, Vol. 19 No. 2, April-June 1995: Newsletter of the Colorado Native Plant Society
https://epublications.regis.edu/aquilegia/1075/thumbnail.jp
Measurement of W Polarisation at LEP
The three different helicity states of W bosons produced in the reaction e+
e- -> W+ W- -> l nu q q~ at LEP are studied using leptonic and hadronic W
decays. Data at centre-of-mass energies \sqrt s = 183-209 GeV are used to
measure the polarisation of W bosons, and its dependence on the W boson
production angle. The fraction of longitudinally polarised W bosons is measured
to be 0.218 \pm 0.027 \pm 0.016 where the first uncertainty is statistical and
the second systematic, in agreement with the Standard Model expectation
Search for Anomalous Couplings in the Higgs Sector at LEP
Anomalous couplings of the Higgs boson are searched for through the processes
e^+ e^- -> H gamma, e^+ e^- -> e^+ e^- H and e^+ e^- -> HZ. The mass range 70
GeV < m_H < 190 GeV is explored using 602 pb^-1 of integrated luminosity
collected with the L3 detector at LEP at centre-of-mass energies
sqrt(s)=189-209 GeV. The Higgs decay channels H -> ffbar, H -> gamma gamma, H
-> Z\gamma and H -> WW^(*) are considered and no evidence is found for
anomalous Higgs production or decay. Limits on the anomalous couplings d, db,
Delta(g1z), Delta(kappa_gamma) and xi^2 are derived as well as limits on the H
-> gamma gamma and H -> Z gamma decay rates
Measurement of W Polarisation at LEP
The three different helicity states of W bosons produced in the reaction e+
e- -> W+ W- -> l nu q q~ at LEP are studied using leptonic and hadronic W
decays. Data at centre-of-mass energies \sqrt s = 183-209 GeV are used to
measure the polarisation of W bosons, and its dependence on the W boson
production angle. The fraction of longitudinally polarised W bosons is measured
to be 0.218 \pm 0.027 \pm 0.016 where the first uncertainty is statistical and
the second systematic, in agreement with the Standard Model expectation
Neutral-Current Four-Fermion Production in e+e- Interactions at LEP
Neutral-current four-fermion production, e+e- -> ffff is studied in 0.7/fb of
data collected with the L3 detector at LEP at centre-of-mass energies
root(s)=183-209GeV. Four final states are considered: qqvv, qqll, llll and
llvv, where l denotes either an electron or a muon. Their cross sections are
measured and found to agree with the Standard Model predictions. In addition,
the e+e- -> Zgamma* -> ffff process is studied and its total cross section at
the average centre-of-mass energy 196.6GeV is found to be 0.29 +/- 0.05 +/-
0.03 pb, where the first uncertainty is statistical and the second systematic,
in agreement with the Standard Model prediction of 0.22 pb. Finally, the mass
spectra of the qqll final states are analysed to search for the possible
production of a new neutral heavy particle, for which no evidence is found
Measurement of Exclusive rho+rho- Production in Mid-Virtuality Two-Photon Interactions and Study of the gamma gamma* -> rho rho Process at LEP
Exclusive rho+rho- production in two-photon collisions between a quasi-real
photon, gamma, and a mid-virtuality photon, gamma*, is studied with data
collected at LEP at centre-of-mass energies root(s)=183-209GeV with a total
integrated luminosity of 684.8pb^-1. The cross section of the gamma gamma* ->
rho+ rho- process is determined as a function of the photon virtuality, Q^2,
and the two-photon centre-of-mass energy, W_gg, in the kinematic region:
0.2GeV^2 < Q^2 <0.85GeV^2 and 1.1GeV < W_gg < 3GeV. These results, together
with previous L3 measurements of rho0 rho0 and rho+ rho- production, allow a
study of the gamma gamma* -> rho rho process over the Q^2-region 0.2GeV^2 < Q^2
< 30 GeV^2
Bose-Einstein Correlations of Neutral and Charged Pions in Hadronic Z Decays
Bose-Einstein correlations of both neutral and like-sign charged pion pairs
are measured in a sample of 2 million hadronic Z decays collected with the L3
detector at LEP. The analysis is performed in the four-momentum difference
range 300 MeV < Q < 2 GeV. The radius of the neutral pion source is found to be
smaller than that of charged pions. This result is in qualitative agreement
with the string fragmentation model
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