380 research outputs found
Grape leaf rust mite, Calepitrimerus vitis (Acari: Eriophyidae), a new pest of grapes in British Columbia
The grape leaf rust mite, Calepitrimerus vitis (Nalepa), was first discovered in the interior of British Columbia in 2009 on grape leaves from a commercial vineyard north of Osoyoos. Bronzing of grape leaves confirmed to be caused by C. vitis in summer 2009 was followed by severely stunted shoots and distorted leaves in several vineyards in spring 2010. Numbers and lengths of shoots and fruit clusters were reduced significantly on vines infested with C. vitis. Earlier studies have shown that outbreaks of C. vitis result from pesticide sprays targeted to other pests that damage predator mite populations. Sprays of sulphur-based fungicides early in the season are the recommended method of control
Managing Irrigation and Nitrogen for Moravian Barley in Southern Idaho
Moravian barley has become an important variety in
southern Idaho and its acreage is still increasing. This grow
barley tends to lodge soon after heading. The risk of
lodging is greater if excess nitrogen is present and if the
crop is well-watered before the boot stage. Lodging
decreases the barley's malting quality and may lower
yield because of harvesting problems
Nitrogen Management for Malting Barley
Malting barley is a specialized agricultural crop in which
high yields and quality are production objectives. We evaluated
the effects of different N rates on barley yields and selected
malting quality parameters grown on irrigated silt loam soils
(Xerollic calciorthids). Maximum barley yields having acceptable
malting quality parameters were obtained when the preplant soil
NO?-N plus fertilizer N was between 100 to 120 kg N/ha. About 33
kg N/ha was taken up by the plants from the mineralization of soil
organic N. Higher available N levels decreased malting quality
parameters below acceptable levels. Germination percentage was
not changed by the different N rates
Chiral Magnetic Effect in Hydrodynamic Approximation
We review derivations of the chiral magnetic effect (ChME) in hydrodynamic
approximation. The reader is assumed to be familiar with the basics of the
effect. The main challenge now is to account for the strong interactions
between the constituents of the fluid. The main result is that the ChME is not
renormalized: in the hydrodynamic approximation it remains the same as for
non-interacting chiral fermions moving in an external magnetic field. The key
ingredients in the proof are general laws of thermodynamics and the
Adler-Bardeen theorem for the chiral anomaly in external electromagnetic
fields. The chiral magnetic effect in hydrodynamics represents a macroscopic
manifestation of a quantum phenomenon (chiral anomaly). Moreover, one can argue
that the current induced by the magnetic field is dissipation free and talk
about a kind of "chiral superconductivity". More precise description is a
ballistic transport along magnetic field taking place in equilibrium and in
absence of a driving force. The basic limitation is exact chiral limit while
the temperature--excitingly enough- does not seemingly matter. What is still
lacking, is a detailed quantum microscopic picture for the ChME in
hydrodynamics. Probably, the chiral currents propagate through
lower-dimensional defects, like vortices in superfluid. In case of superfluid,
the prediction for the chiral magnetic effect remains unmodified although the
emerging dynamical picture differs from the standard one.Comment: 35 pages, prepared for a volume of the Springer Lecture Notes in
Physics "Strongly interacting matter in magnetic fields" edited by D.
Kharzeev, K. Landsteiner, A. Schmitt, H.-U. Ye
Predicting Nitrogen Fertilizer Needs for Sugarbeets from Residual Nitrate and Mineralizable Nitrogen
Nitrogen (N) fertilizer management for sugarbeet (Beta vulgaris L.)
production requires more precise information than for most crops.
Inadequate N limits plant growth and root yield, but excess N may
reduce both sucrose percentage and recoverable sucrose (7). Also,
excess N may stimulate more leaf growth than necessary. The rate and
timing of N fertilizer applications are not only important in supplying
crop N needs, but can influence the amount of N lost by leaching and
denitrification. Soil and plant tissue tests can provide essential data For
decision-making for efficient and economical use of N fertilizer.
Recent studies have shown that the NO?-N level in the soil before
planting is closely related to sucrose production when N is limiting (8,
12). Inclusion of the N mineralization capacity of the soils would be
expected to improve the relationship. Stanford and Smith (14) showed
that the mineralization capacity varies with soil type and location.
Therefore, a soil test for N that would have general applicability should
include the mineralization capacity of the soil, and the interpretation of
these tests should include some knowledge of expected irrigation practices.
A soil test for NO?-N may suffice as an index of N fertilizer needs
for a given soil and irrigation level.
Recently, Carter et al. (5) showed that sucrose production was
closely related to available soil N, as indicated by a soil test that included
both mineralizable N and NO?-N. The objective of our study was to
evaluate the soil test-yield relationship, developed from experimental
data at one location in south central Idaho, for predicting N fertilizer
needs throughout southern Idaho under various irrigation management
practices
On the magnetic stability at the surface in strongly correlated electron systems
The stability of ferromagnetism at the surface at finite temperatures is
investigated within the strongly correlated Hubbard model on a semi-infinite
lattice. Due to the reduced surface coordination number the effective Coulomb
correlation is enhanced at the surface compared to the bulk. Therefore, within
the well-known Stoner-picture of band ferromagnetism one would expect the
magnetic stability at the surface to be enhanced as well. However, by taking
electron correlations into account well beyond the Hartree-Fock (Stoner) level
we find the opposite behavior: As a function of temperature the magnetization
of the surface layer decreases faster than in the bulk. By varying the hopping
integral within the surface layer this behavior becomes even more pronounced. A
reduced hopping integral at the surface tends to destabilize surface
ferromagnetism whereas the magnetic stability gets enhanced by an increased
hopping integral. This behavior represents a pure correlation effect and can be
understood in terms of general arguments which are based on exact results in
the limit of strong Coulomb interaction.Comment: 6 pages, RevTeX, 4 eps figures, accepted (Phys. Rev. B), for related
work and info see http://orion.physik.hu-berlin.d
Modelling Non-linear Crowd Dynamics in Bio-PEPA
Emergent phenomena occur due to the pattern of non-linear and distributed local interactions between the elements of a system over time. Surprisingly, agent based crowd models, in which the movement of each individual follows a limited set of simple rules, often re-produce quite closely the emergent behaviour of crowds that can be observed in reality. An example of such phenomena is the spontaneous self-organisation of drinking parties in the squares of cities in Spain, also known as "El Botellon" [20]. We revisit this case study providing an elegant stochastic process algebraic model in Bio-PEPA amenable to several forms of analyses, among which simulation and fluid flow analysis. We show that a fluid flow approximation, i.e. a deterministic reading of the average behaviour of the system, can provide an alternative and efficient way to study the same emergent behaviour as that explored in [20] where simulation was used instead. Besides empirical evidence, also an analytical justification is provided for the good correspondence found between simulation results and the fluid flow approximation
A comment on multiple vacua, particle production and the time dependent AdS/CFT correspondence
We give an explicit formulation of the time dependent AdS/CFT correspondence
when there are multiple vacua present in Lorentzian signature. By computing
sample two point functions we show how different amplitudes are related by
cosmological particle production. We illustrate our methods in two example
spacetimes: (a) a ``bubble of nothing'' in AdS space, and (b) an asymptotically
locally AdS spacetime with a bubble of nothing on the boundary. In both cases
the alpha vacua of de Sitter space make an interesting appearance.Comment: 9 page
Treatment planning for patients with low rectal cancer in a multicenter prospective organ preservation study
Background
Non-surgical management of rectal cancer relies on (chemo)radiotherapy as the definitive treatment modality. This study reports and evaluates the clinical high dose radiotherapy treatment plans delivered to patients with low resectable rectal cancer in a Danish multicenter trial.
Methods
The Danish prospective multicenter phase II Watchful Waiting 2 trial (NCT02438839) investigated definitive chemoradiation for non-surgical management of low rectal cancer. Three Danish centers participated in the trial and committed to protocol-specified treatment planning and delivery requirements. The protocol specified a dose of 50.4 Gy in 28 fractions to the elective volume (CTV-/PTV-E) and a concomitant boost of 62 Gy in 28 fractions to the primary target volume (CTV-/PTV-T).
Results
The trial included 108 patients, of which 106 treatment plans were available for retrospective analysis. Dose coverage planning goals for the main target structures were fulfilled for 94% of the treatment plans. However, large intercenter differences in doses to organs-at-risk (OARs) were seen, especially for the intestines. Five patients had a V60Gy>10 cm3 for the intestines and two patients for the bladder.
Conclusion
Prescribed planning goals for target coverage were fulfilled for 94% of the treatment plans, however analysis of OAR doses and volumes indicated intercenter variations. Dose escalation to 62 Gy (as a concomitant boost to the primary tumor) introduced no substantial high dose volumes (>60 Gy) to the bladder and intestines. The treatment planning goals may be used for future prospective evaluation of highdose radiotherapy for organ preservation for low rectal cancer
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