451 research outputs found
Evaluation of environmentally friendly products for control of fungal diseases of grapes
Various environmentally friendly products were tested for efficacy in controlling powdery mildew, downy mildew, black rot, Phomopsis, and Botrytis bunch rot in grapes over several years. The products tested were: JMS stylet oil (paraffinic oil), Serenade (Bacillus subtilis), Croplife (citrus and coconut extract) + Plant food (foliar fertilizer), Armicarb (potassium bicarbonate), Elexa (chitosan), Milsana (giant knotweed extract), and AQ10 (Ampelomyces quisqua/is). JMS Stylet Oil, Armicarb, Serenade, AQ10, Elexa, and Milsana all provided moderate control of downy and powdery mildew. JMS Stylet Oil and Armicarb also reduced Phomopsis rachis infections. Armicarb looks especially promising for black rot control. Serenade and Croplife + Plantfood provided moderate to good control of Botrytis bunch rot, and moderate control of downy mildew and Phomopsis leaf spot. Milsana provided moderate control of Botrytis bunch rot. The tested products were often out-performed by standard or new products, especially under the humid conditions common in Michigan. However, some products appeared promising for certain diseases and merit further study, especially those that may be of interest to organic growers. Optimizing timing of these products may enhance their performance, since most of them are protectants and have little or no eradicant activity
Effects of electroplating on the mechanical properties of stereolithography and laser sintered parts
This paper provides a quantitative and qualitative assessment of the effects of
electroplating on polymer parts made by stereolithography and laser sintering. A
series of test samples were coated with copper and nickel with varying thickness.
Thicker coatings (120μm) were reproduced with a repeatability that should not
adversely affect the tolerances with which such parts may be produced given the
tolerances of the initial rapid prototyping processes themselves. Thinner coatings
(20μm) resulted in a smother surface finish than thicker coatings for
stereolithography parts, however the converse was true for laser-sintered parts.
Composite theory was used to predict that thicker coating would lead to higher
Young’s modulus in parts and this was shown to be true in physical tests although
the practical values were lower than the predicted values especially for thicker
coatings. Physical tests also confirmed that thicker coatings increased UTS and
impact energy but had a minimal effect on the ductility of parts
Search for Exotic Mesons in pi- P Interactions at 18 GeV/c
The recent search for non mesons in interactions at
Brookhaven National Laboratory is summarized. Many final states such as , , , , , ,
which are favored decay modes of exotics, are under investigation.Comment: 9 pages, PostScript, Presented at the International School of Nuclear
Physics, Erice, Sicily, Italy, September 199
Tau and Charm physics highlights
In tau physics, we are at the frontier between the completion of the LEP
program and the start of analyses from b-factories, which are expected to
produce results in the coming years. Nice results from CLEO are steadily
delivered in the meantime. For charm, impressive progress have been achieved by
fixed target experiments in the search for CP violation and D^0 - \bar D^0
oscillations. First results from b-factories demonstrate the power of these
facilities in such areas. The novel measurement of the D* width by CLEO happens
to be rather different from current expectations. The absence of a charm
factory explains the lack or the very slow progress in the absolute scale
determinations for charm decays.Comment: "Typos corrected and references added
Rare charm meson decays D->Pl^+l^- and c->ul^+l^- in SM and MSSM
We study the nine possible rare charm meson decays D->Pl^+l^-
(P=pi,K,eta,eta') using the Heavy Meson Chiral Lagrangians and find them to be
dominated by the long distance contributions. The decay D^+ -> pi^+l^+l^- with
the branching ratio 1*10^(-6) is expected to have the best chances for an early
experimental discovery. The short distance contribution in the five Cabibbo
suppressed channels arises via the c->ul^+l^- transition; we find that this
contribution is detectable only in the D->pi l^+l^- decay, where it dominates
the differential spectrum at high-q^2. The general Minimal Supersymmetric
Standard Model can enhance the c->ul^+l^- rate by up to an order of magnitude;
its effect on the D->Pl^+l^- rates is small since the c->ul^+l^- enhancement is
sizable in low-q^2 region, which is inhibited in the hadronic decay.Comment: 17 page
A Heavy-Light Chiral Quark Model
We present a new chiral quark model for mesons involving a heavy and a light
(anti-) quark. The model relates various combinations of a quark - meson
coupling constant and loop integrals to physical quantities. Then, some
quantities may be predicted and some used as input. The extension from other
similar models is that the present model includes the lowest order gluon
condensate of the order (300 MeV)^4 determined by the mass splitting of the 0^-
and the 1^- heavy meson states. Within the model, we find a reasonable
description of parameters such as the decay constants f_B and f_D, the
Isgur-Wise function and the axial vector coupling g_A in chiral perturbation
theory for light and heavy mesons.Comment: 31 pages, 13 figures, RevTex4.
Observation of a New J(PC)=1(+-) Isoscalar State in the Reaction Pi- Proton -> Omega Eta Neutron at 18 GeV/c
Results are presented on a partial wave analysis of the Omega Eta final state
produced in Pi- Proton interactions at 18 GeVc where Omega -> Pi+ Pi- Pi0, Pi0
-> 2 Gammas, and Eta -> 2 Gammas. We observe the previously unreported decay
mode Omega(1650) -> Omega Eta and a new 1(+-) meson state h1(1595) with a mass
M=1594(15)(+10)(-60) MeV/c^2 and a width Gamma=384(60)(+70)(-100) MeV/c^2. The
h1(1595) state exhibits resonant-like phase motion relative to the Omega(1650).Comment: Submitted to Physics Letters B Eight total pages including 11 figures
and 1 tabl
Recommended from our members
Opioid suppression of conditioned anticipatory brain responses to breathlessness
Opioid painkillers are a promising treatment for chronic breathlessness, but are associated with potentially fatal side effects. In the treatment of breathlessness, their mechanisms of action are unclear. A better understanding might help to identify safer alternatives. Learned associations between previously neutral stimuli (e.g. stairs) and repeated breathlessness induce an anticipatory threat response that may worsen breathlessness, contributing to the downward spiral of decline seen in clinical populations. As opioids are known to influence associative learning, we hypothesized that they may interfere with the brain processes underlying a conditioned anticipatory response to breathlessness in relevant brain areas, including the amygdala and the hippocampus.
Healthy volunteers viewed visual cues (neutral stimuli) immediately before induction of experimental breathlessness with inspiratory resistive loading. Thus, an association was formed between the cue and breathlessness. Subsequently, this paradigm was repeated in two identical neuroimaging sessions with intravenous infusions of either low-dose remifentanil (0.7ng/ml target controlled infusion) or saline (randomised).
During saline infusion, breathlessness anticipation activated the right anterior insula and the adjacent operculum. Breathlessness was associated with activity in a network including the insula, operculum, dorsolateral prefrontal cortex, anterior cingulate cortex and the primary sensory and motor cortices.
Remifentanil reduced breathlessness unpleasantness but not breathlessness intensity. Remifentanil depressed anticipatory activity in the amygdala and the hippocampus that correlated with reductions in breathlessness unpleasantness. During breathlessness, remifentanil decreased activity in the anterior insula, anterior cingulate cortex and sensory motor cortices. Remifentanil-induced reduction in breathlessness unpleasantness was associated with increased activity in the rostral anterior cingulate cortex and nucleus accumbens, components of the endogenous opioid system known to decrease the perception of aversive stimuli.
These findings suggest that in addition to effects on brainstem respiratory control, opioids palliate breathlessness through an interplay of altered associative learning mechanisms. These mechanisms provide potential targets for novel ways to develop and assess treatments for chronic breathlessness
Kinetic Monte Carlo Simulation of Strained Heteroepitaxial Growth with Intermixing
An efficient method for the simulation of strained heteroepitaxial growth
with intermixing using kinetic Monte Carlo is presented. The model used is
based on a solid-on-solid bond counting formulation in which elastic effects
are incorporated using a ball and spring model. While idealized, this model
nevertheless captures many aspects of heteroepitaxial growth, including
nucleation, surface diffusion, and long range effects due elastic interaction.
The algorithm combines a fast evaluation of the elastic displacement field with
an efficient implementation of a rejection-reduced kinetic Monte Carlo based on
using upper bounds for the rates. The former is achieved by using a multigrid
method for global updates of the displacement field and an expanding box method
for local updates. The simulations show the importance of intermixing on the
growth of a strained film. Further the method is used to simulate the growth of
self-assembled stacked quantum dots
- …