1,771 research outputs found
High dillution of Staphysagria and fruit fly biotherapic preparations to manage South American fruit fly, Anastrepha fraterculus, in organic peach orchards.
The peach, Prunus persica, is an important economic crop in southern Brazil, where family farms are predominantly small. The South American fruit fly, Anastrepha fraterculus is a limiting factor to increased production in orchard crops. Increased organic production in Brazil has stimulated research to find ecological based pest management. This research was carried out in order to evaluate the efficacy of preparations at high dilution in managing A. fraterculus in organic peach orchards. Experiments were conducted under field conditions in randomized blocks during 2003/04 and 2004/05. Treatments consisted of A. fraterculus nosodes and Staphysagria homeopathic preparations, both at two high dilution levels, 3CH and 6CH (centesimal hahnemannian dilution method), applied at two spray intervals, 5 and 10 days, and a control. Fruit losses due to A. fraterculus infestation varied from 40 to 98.3%. Although there were significant differences among treatments in the first harvest of two of the three experiments there were no significant differences in the second harvest of any of the experiments. None of the homeopathic preparations reduced the incidence of infested fruit significantly below that of the water control in any of the three experiments. Further studies must combine other strategies such as bagging fruits and planting of early season cultivars. Variation on high dilution potency, dose, and frequency of application must also be considered
Fluorescence excitation spectrum, lifetimes and photoisomerization of jet-cooled conformers of 1,1 '- bi(benzocyclobutylidene)
First measurements of fluorescence excitation spectra of the recently synthesized rigid stilbene analogue 1,1'- bi(benzocyclobutylidene) in a supersonic jet expansion show that, in contrast to the parent compound, both the trans- and the cis-conformer fluoresce under these conditions. The excitation energy dependence of fluorescence lifetimes indicates the onset of an efficient non-radiative decay channel above energy thresholds of 1340 cm(-1) and 990 cm(-1) for the trans- and cis-form, respectively, which is assigned to photoisomerization in the singlet state. From an RRKM analysis of the microcanonical rate coefficients an estimate of the high pressure limit of the thermal photoisomerization rate coefficient is obtained and compared with photoisomerization rate coefficients measured in low viscosity solution and in thermal vapor. There are strong indications that for this compound there are no dynamic or static solvent induced effects that lead to an anomalous acceleration of the reaction in solution
The Separable Kernel of Nucleon-Nucleon Interaction in the Bethe-Salpeter Approach
The dispersion relations for nucleon-nucleon (NN) T-matrix in the framework
of Bethe-Salpeter equation for two spin one-half particle system and with
separable kernel of interaction are considered in the paper. The developed
expressions are applied for construction of the separable kernel of interaction
for S partial-waves in singlet and triplet channels. We calculate the low
energy scattering parameters and the phase shifts and also the deuteron binding
energy with the separable interaction. The approach can be easily extended to
higher partial-waves for NN-scattering and other reactions (anti N N-, pi
N-scattering).Comment: RevTex 4 style, 9 pages, 1 figur
Dimensional stability of curved panels with cocured stiffeners and cobonded frames
Closed form and finite element analyses are presented for axial direction and transverse direction dimensional stability of skin/stringer panels. Several sensitivity studies are presented to illustrate the influence of various design parameters on the dimensional stability of these panels. Panel geometry, material properties (stiffness and coefficient of thermal expansion), restraint conditions and local details, such as resin fillets, all combine to influence dimensional stability, residual and assembly forces
Relativistic three-body bound states and the reduction from four to three dimensions
Beginning with an effective field theory based upon meson exchange, the
Bethe-Salpeter equation for the three-particle propagator (six-point function)
is obtained. Using the one-boson-exchange form of the kernel, this equation is
then analyzed using time-ordered perturbation theory, and a three-dimensional
equation for the propagator is developed. The propagator consists of a
pre-factor in which the relative energies are fixed by the initial state of the
particles, an intermediate part in which only global propagation of the
particles occurs, and a post-factor in which relative energies are fixed by the
final state of the particles. The pre- and post-factors are necessary in order
to account for the transition from states where particles are off their mass
shell to states described by the global propagator with all of the particle
energies on shell. The pole structure of the intermediate part of the
propagator is used to determine the equation for the three-body bound state: a
Schr{\"o}dinger-like relativistic equation with a single, global Green's
function. The role of the pre- and post-factors in the relativistic dynamics is
to incorporate the poles of the breakup channels in the initial and final
states. The derivation of this equation by integrating over the relative times
rather than via a constraint on relative momenta allows the inclusion of
retardation and dynamical boost corrections without introducing unphysical
singularities.Comment: REVTeX, 21 pages, 4 figures, epsf.st
Relativistic Corrections to the Triton Binding Energy
The influence of relativity on the triton binding energy is investigated. The
relativistic three-dimensional version of the Bethe-Salpeter equation proposed
by Blankenbecler and Sugar (BbS) is used. Relativistic (non-separable)
one-boson-exchange potentials (constructed in the BbS framework) are employed
for the two-nucleon interaction. In a 34-channel Faddeev calculation, it is
found that relativistic effects increase the triton binding energy by about 0.2
MeV. Including charge-dependence (besides relativity), the final triton binding
energy predictions are 8.33 and 8.16 MeV for the Bonn A and B potential,
respectively.Comment: 25 pages of text (latex), 1 figure (not included, available upon
request
Using self-definition to predict the influence of procedural justice on organizational, interpersonal, and job/task-oriented citizenship behaviors
An integrative self-definition model is proposed to improve our understanding of how procedural justice affects different outcome modalities in organizational behavior. Specifically, it is examined whether the strength of different levels of self-definition (collective, relational, and individual) each uniquely interact with procedural justice to predict organizational, interpersonal, and job/task-oriented citizenship behaviors, respectively. Results from experimental and (both single and multisource) field data consistently revealed stronger procedural justice effects (1) on organizational-oriented citizenship behavior among those who define themselves strongly in terms of organizational characteristics, (2) on interpersonal-oriented citizenship behavior among those who define themselves strongly in terms of their interpersonal relationships, and (3) on job/task-oriented citizenship behavior among those who define themselves weakly in terms of their distinctiveness or uniqueness. We discuss the relevance of these results with respect to how employees can be motivated most effectively in organizational settings
Dysregulated autophagy in restrictive cardiomyopathy due to Pro209Leu mutation in BAG3
Myofibrillary myopathies (MFM) are hereditary myopathies histologically characterized by degeneration of myofibrils and aggregation of proteins in striated muscle. Cardiomyopathy is common in MFM but the pathophysiological mechanisms are not well understood. The BAG3-Pro209Leu mutation is associated with early onset MFM and severe restrictive cardiomyopathy (RCM), often necessitating heart transplantation during childhood. We report on a young male patient with a BAG3-Pro209Leu mutation who underwent heart transplantation at eight years of age. Detailed morphological analyses of the explanted heart tissue showed intracytoplasmic inclusions, aggregation of BAG3 and desmin, disintegration of myofibers and Z-disk alterations. The presence of undegraded autophagosomes, seen by electron microscopy, as well as increased levels of p62, LC3-I and WIPI1, detected by immunohistochemistry and western blot analyses, indicated a dysregulation of autophagy. Parkin and PINK1, proteins involved in mitophagy, were slightly increased whereas mitochondrial OXPHOS activities were not altered. These findings indicate that altered autophagy plays a role in the pathogenesis and rapid progression of RCM in MFM caused by the BAG3-Pro209Leu mutation, which could have implications for future therapeutic strategies
The role of polysaccharide intercellular adhesin (PIA) in Staphylococcus epidermidis adhesion to host tissues and subsequent antibiotic tolerance
The aim of this study was to determine the role of polysaccharide intercellular adhesin (PIA) in Staphylococcus epidermidis adhesion to host tissues and subsequent antibiotic tolerance. The adherence of S. epidermidis 1457 and the mutant defective in PIA production (1457-M10) to urinary epithelium and endothelium was estimated by colony counting. Minimum bactericidal concentration and mean reduction of cellular activity (XTT) following antibiotic exposure was determined for planktonic and adhered bacteria. S. epidermidis 1457 adhered to a greater extent to both cells than the mutant strain. The adhered strains had a significantly higher antimicrobial tolerance than their planktonic counterparts. The mutant strain was, in general, the most susceptible to the antibiotics assayed. In conclusion, PIA may influence S. epidermidis adherence to host tissues and their antimicrobial susceptibility. Initial adhesion may be the main step for the acquisition of resistance in S. epidermidis
Spin and e-e interactions in quantum dots: Leading order corrections to universality and temperature effects
We study the statistics of the spacing between Coulomb blockade conductance
peaks in quantum dots with large dimensionless conductance g. Our starting
point is the ``universal Hamiltonian''--valid in the g->oo limit--which
includes the charging energy, the single-electron energies (described by random
matrix theory), and the average exchange interaction. We then calculate the
magnitude of the most relevant finite g corrections, namely, the effect of
surface charge, the ``gate'' effect, and the fluctuation of the residual e-e
interaction. The resulting zero-temperature peak spacing distribution has
corrections of order Delta/sqrt(g). For typical values of the e-e interaction
(r_s ~ 1) and simple geometries, theory does indeed predict an asymmetric
distribution with a significant even/odd effect. The width of the distribution
is of order 0.3 Delta, and its dominant feature is a large peak for the odd
case, reminiscent of the delta-function in the g->oo limit. We consider finite
temperature effects next. Only after their inclusion is good agreement with the
experimental results obtained. Even relatively low temperature causes large
modifications in the peak spacing distribution: (a) its peak is dominated by
the even distribution at kT ~ 0.3 Delta (at lower T a double peak appears); (b)
it becomes more symmetric; (c) the even/odd effect is considerably weaker; (d)
the delta-function is completely washed-out; and (e) fluctuation of the
coupling to the leads becomes relevant. Experiments aimed at observing the T=0
peak spacing distribution should therefore be done at kT<0.1 Delta for typical
values of the e-e interaction.Comment: 15 pages, 4 figure
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