287 research outputs found
How do brassinosteroids fit in bud outgrowth models?
Advance Access Publication 17 October 2023.
OnlinePublShort stature crops were developed during the green revolution mainly due to their resistance to falling over (lodging), improved crop harvestability and management, and a greater proportion of biomass in the grains, leading to superior yield. These crops were disrupted in the gibberellin (GA) pathway, which caused the reduced height (Gao and Chu, 2020). GA disruption can introduce unwanted effects in other important traits such as fertility, leaf expansion, seed quality, and stress response (Gao and Chu, 2020). Hence, there are currently efforts to uncouple negative side effects of GA-related short stature or utilize alternative dwarfing pathways, such as brassinosteroids (BRs).Jack H. Kelly and Philip B. Brewe
Hidden magnetic transitions in thermoelectric layered cobaltite, [CaCoO][CoO]
A positive muon spin rotation and relaxation (SR) experiment on
[CaCoO][CoO], ({\sl i.e.}, CaCoO, a layered
thermoelectric cobaltite) indicates the existence of two magnetic transitions
at 100 K and 400 - 600 K; the former is a transition from a paramagnetic
state to an incommensurate ({\sf IC}) spin density wave ({\sf SDW}) state. The
anisotropic behavior of zero-field SR spectra at 5 K suggests that the
{\sf IC-SDW} propagates in the - plane, with oscillating moments directed
along the c-axis; also the {\sf IC-SDW} is found to exist not in the
[CaCoO] subsystem but in the [CoO] subsystem. In addition, it is
found that the long-range {\sf IC-SDW} order completes below 30 K,
whereas the short-range order appears below 100 K. The latter transition is
interpreted as a gradual change in the spin state of Co ions %% at temperatures
above 400 K. These two magnetic transitions detected by SR are found to
correlate closely with the transport properties of
[CaCoO][CoO].Comment: 7 pages, 8 figures. to be appeared in Phys. Rev.
Excess electron transport in cryoobjects
Experimental results on excess electron transport in solid and liquid phases of Ne, Ar, and solid N₂-Ar mixture are presented and compared with those for He. Muon spin relaxation technique in frequently switching electric fields was used to study the phenomenon of delayed muonium formation: excess electrons liberated in the m⁺ ionization track converge upon the positive muons and form Mu (m⁺e⁻) atoms. This process is shown to be crucially dependent upon the electron`s interaction with its environment (i.e., whether it occupies the conduction band or becomes localized in a bubble of tens of angstroms in radius) and upon its mobility in these states. The characteristic lengths involved are 10⁻⁶-10⁻⁴ cm, the characteristic times range from nanoseconds to tens microseconds. Such a microscopic length scale sometimes enables the electron spend its entire free lifetime in a state which may not be detected by conventional macroscopic techniques. The electron transport processes are compared in: liquid and solid helium (where electron is localized in buble); liquid and solid neon (where electrons are delocalized in solid and the coexistence of localized and delocalized electrons states was found in liquid recently); liquid and solid argon (where electrons are delocalized in both phases); orientational glass systems (solid N₂-Ar mixtures), where our results suggest that electrons are localized in orientational glass. This scaling from light to heavy rare gases enables us to reveal new features of excess electron localization on microscopic scale. Analysis of the experimental data makes it possible to formulate the following tendency of the muon end-of-track structure in condensed rare gases. The muon-self track interaction changes from the isolated pair (muon plus the nearest track electron) in helium to multi-pair (muon in the vicinity of tens track electrons and positive ions) in argon
The hyperfine transition in light muonic atoms of odd Z
The hyperfine (hf) transition rates for muonic atoms have been re-measured
for select light nuclei, using neutron detectors to evaluate the time
dependence of muon capture. For F = 5.6 (2)
s for the hf transition rate, a value which is considerably more
accurate than previous measurements. Results are also reported for Na, Al, P,
Cl, and K; that result for P is the first positive identification.Comment: 12 pages including 5 tables and 4 figures, RevTex, submitted to Phys.
Rev.
Magnetic properties of exactly solvable doubly decorated Ising-Heisenberg planar models
Applying the decoration-iteration procedure, we introduce a class of exactly
solvable doubly decorated planar models consisting both of the Ising- and
Heisenberg-type atoms. Exact solutions for the ground state, phase diagrams and
basic physical quantities are derived and discussed. The detailed analysis of
the relevant quantities suggests the existence of an interesting quantum
antiferromagnetic phase in the system.Comment: 9 pages, 9 figures, submitted to Physical Review
Melting and Dimensionality of the Vortex Lattice in Underdoped YBa2Cu3O6.60
Muon spin rotation measurements of the magnetic field distribution in the
vortex state of the oxygen deficient high-Tc superconductor YBa{2}Cu{3}O{6.60}
reveal a vortex-lattice melting transition at much lower temperature than that
in the fully oxygenated material. The transition is best described by a model
in which adjacent layers of ``pancake'' vortices decouple in the liquid phase.
Evidence is also found for a pinning-induced crossover from a solid 3D to
quasi-2D vortex lattice, similar to that observed in the highly anisotropic
superconductor Bi{2+x}Sr{2-x}CaCu{2}O{8+y}.Comment: 8 pages, 4 figures, 5 postscript file
Correlations Between Charge Ordering and Local Magnetic Fields in Overdoped YBaCuO
Zero-field muon spin relaxation (ZF-SR) measurements were undertaken on
under- and overdoped samples of superconducting YBaCuO to
determine the origin of the weak static magnetism recently reported in this
system. The temperature dependence of the muon spin relaxation rate in
overdoped crystals displays an unusual behavior in the superconducting state. A
comparison to the results of NQR and lattice structure experiments on highly
doped samples provides compelling evidence for strong coupling of charge, spin
and structural inhomogeneities.Comment: 4 pages, 4 figures, new data, new figures and modified tex
Athlete experiences of disordered eating in sport
To date, research into disordered eating in sport has focused on the prevalence and the identification of putative risk factors. Findings suggest that elite female athletes participating in sports with a focus on leanness or aesthetics are at greatest risk. A paucity of research remains as to the period after onset and how existing sufferers manage their illness over time. In line with the principles of interpretative phenomenological analysis (IPA), this study 'gives voice' to four athletes who have experienced disordered eating, documenting their personal accounts and interpreting these accounts from a psychological perspective. In‐depth, semi‐structured interviews were conducted and verbatim transcripts were analysed according to the procedures of IPA. Three superordinate themes emerged from the data: the struggle to disclose, social support needs and identity challenges. Athletes' stories provided rich descriptions of their subjective disordered eating experiences. Their accounts give critical insight into the impact of eating disturbance on the lives of athletes. Future research should continue to identify athletes with existing eating problems in order to improve understanding as to how such individuals can best be helped
Prevalence of High-Risk Human Papillomavirus by RNA Assay in Home Self-Collected Samples among Underscreened People in North Carolina
Background Low-income and uninsured people with a cervix (PWC) are at the highest risk of being underscreened for cervical cancer. We evaluated the prevalence of high-risk human papillomavirus (hrHPV) on home self-collected samples, as well as rates of in-clinic follow-up and risk factors associated with hrHPV positivity in this at-risk population. Methods My Body My Test 3 was conducted between 2016 and 2019 in North Carolina among individuals aged 25 to 64 years, overdue for cervical cancer screening, and with incomes of <250% of the US Federal Poverty Level. Our analytic sample included participants randomized to the self-collection arm who returned self-collected cervicovaginal brush samples for HPV testing (n = 329). Samples were tested for 14 hrHPV types by an HPV RNA assay and further genotyped for HPV-16 and HPV-18/45. We examined behavioral risk factors for hrHPV positivity using logistic regression and between-subject t tests. Results High-risk HPV RNA prevalence was 16% (n = 52/329) in self-collected samples. Of the hrHPV-positive participants, 24 (46%) presented for in-clinic cervical cancer screening, compared with 56 (20%) of hrHPV-negative participants. Those with ≥2 sexual partners in the past year were twice as likely to be hrHPV positive in adjusted analyses (adjusted odds ratio, 2.00 [95% confidence interval, 1.03-3.88]). High-risk HPV-positive and HPV-negative participants had similar attitudes toward screening, with the exception of hrHPV-positive participants who reported a lower perceived risk of cervical cancer than those who were hrHPV negative (P < 0.05). Conclusion The hrHPV RNA prevalence was similar to findings in other underscreened PWC in the United States. Efforts to reach underscreened PWC are critical for cervical cancer prevention. Future studies aimed at home self-collection should address methods of increasing clinic attendance and completion of treatment among those with HPV-positive results
Muon-spin-rotation study of the effect of Zn substitution on magnetism in YBa2Cu3Ox
The magnetic properties of YBa2(Cu0.96Zn0.04)3Ox were studied in detail by means of muon spin rotation and relaxation for 6.0≤x≤6.92. The complete magnetic phase diagram was mapped out and a disordered magnetic state was found to persist between x=6.4 and x≃6.7 (metallic transition), in contrast with pure YBa2Cu3Ox. The appearance of this magnetic state is attributed to the effect of Zn on the doped hole dynamics and might be associated with the freezing of local moments due to Zn (6.43≤x≤6.88), which were also detected here, in the paramagnetic state
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