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Search Results: 1 - 10 of 149730 matches for " H. Hindorf "
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Coffee Wilt Disease (Gibberella xylarioides Heim and Saccas) in Forest Coffee Systems of Southwest and Southeast Ethiopia
Sihen Getachew,Girma Adugna,Fikre Lemessa,H. Hindorf
Plant Pathology Journal , 2012,
Abstract: Coffee diseases are presumed to be less important in the forest coffee as compared to the garden and plantation systems of coffee production in Ethiopia. In this article, the results of a study conducted on the occurrence and incidence of Coffee Wilt Disease (CWD) and the major factors influencing the disease in four major forests coffee sites in southwest and southeast Ethiopia are discussed. In each forest coffee site, coffee wilt syndrome was assessed in three systematically selected sample plots during dry and wet seasons of 2008 and 2009. Concurrently, three to four samples of infected coffee trees were randomly collected from each plot and the causal pathogen was isolated and identified in the laboratory. The result indicted that CWD was prevalent in the four forest coffee sites, with mean incidence of 27.1 and 29.2% in Harenna during 2008 and 2009 wet seasons, respectively, followed by Berhane-Kontir with mean incidences of 22.1 (2008) and 27.7% (2009). Whereas, Bonga and Yayu forest coffees had comparatively low wilt severity (<10%). The wood samples of most of the infected coffee trees (90.6%) yielded Gibberella xylarioides in the laboratory proving that this pathogen is the main cause of coffee tree death in the forest. The difference in incidence of CWD across the four sites and among fields was strongly associated with human factors and variations in coffee populations. The forest coffee trees in Harenna and Berhane-Kontir (high CWD) are almost transformed to semiforest type by sub-planting coffee seedlings after thinning the dense vegetation cover. These activities are known to create wound to the host and disseminate the fungus spores from tree to tree and from one field to the other. The two independent seedling inoculation tests in the greenhouse evidenced that there were significant variations among coffee accessions in reactions to CWD though most accessions were susceptible. The study showed that CWD is one of the potential biotic factors threatening the genetic diversity of Arabica coffee in most forest coffee sites and thus the disease management practices should duly be considered in planning and implementing forest coffee conservation strategy.
dAcquisition setting optimization and quantitative imaging for 124I studies with the Inveon microPET-CT system
Nadège Anizan, Thomas Carlier, Cecilia Hindorf, Jacques Barbet, Manuel Bardiès
EJNMMI Research , 2012, DOI: 10.1186/2191-219x-2-7
Abstract: The noise equivalent count rate [NECR], the scatter fraction [SF], and the gamma-prompt fraction [GF] were used to determine the best acquisition parameters for mouse- and rat-sized phantoms filled with 124I. An image-quality phantom as specified by the National Electrical Manufacturers Association NU 4-2008 protocol was acquired and reconstructed with two-dimensional filtered back projection, 2D ordered-subset expectation maximization [2DOSEM], and 3DOSEM with maximum a posteriori [3DOSEM/MAP] algorithms, with and without attenuation correction, scatter correction, and gamma-prompt correction (weighted uniform distribution subtraction).Optimal energy windows were established for the rat phantom (390 to 550 keV) and the mouse phantom (400 to 590 keV) by combining the NECR, SF, and GF results. The coincidence time window had no significant impact regarding the NECR curve variation. Activity concentration of 124I measured in the uniform region of an image-quality phantom was underestimated by 9.9% for the 3DOSEM/MAP algorithm with attenuation and scatter corrections, and by 23% with the gamma-prompt correction. Attenuation, scatter, and gamma-prompt corrections decreased the residual signal in the cold insert.The optimal energy windows were chosen with the NECR, SF, and GF evaluation. Nevertheless, an image quality and an activity quantification assessment were required to establish the most suitable reconstruction algorithm and corrections for 124I small animal imaging.Small animal imaging is an active area of research for the investigation of new pharmaceuticals and treatment regimens. In vivo imaging permits longitudinal studies to be performed [1]. Quantitative imaging also provides a basis for the calculation of the absorbed dose for radioimmunotherapy applications since it yields both the pharmacokinetics (SPECT or positron-emission tomography [PET]) and the anatomy and density of the tissues (computed tomography [CT]) [2]. Most PET studies are performed with 18
Euler-Lagrange Elasticity: Differential Equations for Elasticity without Stress or Strain  [PDF]
H. H. Hardy
Journal of Applied Mathematics and Physics (JAMP) , 2013, DOI: 10.4236/jamp.2013.17004

Differential equations to describe elasticity are derived without the use of stress or strain. The points within the body are the independent parameters instead of strain and surface forces replace stress tensors. These differential equations are a continuous analytical model that can then be solved using any of the standard techniques of differential equations. Although the equations do not require the definition stress or strain, these quantities can be calculated as dependent parameters. This approach to elasticity is simple, which avoids the need for multiple definitions of stress and strain, and provides a simple experimental procedure to find scalar representations of material properties in terms of the energy of deformation. The derived differential equations describe both infinitesimal and finite deformations.

Euler-Lagrange Elasticity with Dynamics  [PDF]
H. H. Hardy
Journal of Applied Mathematics and Physics (JAMP) , 2014, DOI: 10.4236/jamp.2014.213138
Abstract: The equations of Euler-Lagrange elasticity describe elastic deformations without reference to stress or strain. These equations as previously published are applicable only to quasi-static deformations. This paper extends these equations to include time dependent deformations. To accomplish this, an appropriate Lagrangian is defined and an extrema of the integral of this Lagrangian over the original material volume and time is found. The result is a set of Euler equations for the dynamics of elastic materials without stress or strain, which are appropriate for both finite and infinitesimal deformations of both isotropic and anisotropic materials. Finally, the resulting equations are shown to be no more than Newton's Laws applied to each infinitesimal volume of the material.
Linear Algebra Provides a Basis for Elasticity without Stress or Strain  [PDF]
H. H. Hardy
Soft (Soft) , 2015, DOI: 10.4236/soft.2015.43003
Abstract: Linear algebra provides insights into the description of elasticity without stress or strain. Classical descriptions of elasticity usually begin with defining stress and strain and the constitutive equations of the material that relate these to each other. Elasticity without stress or strain begins with the positions of the points and the energy of deformation. The energy of deformation as a function of the positions of the points within the material provides the material properties for the model. A discrete or continuous model of the deformation can be constructed by minimizing the total energy of deformation. As presented, this approach is limited to hyper-elastic materials, but is appropriate for infinitesimal and finite deformations, isotropic and anisotropic materials, as well as quasi-static and dynamic responses.
Spectral resolution in hyperbolic orbifolds, quantum chaos, and cosmology
H. Then
Physics , 2007,
Abstract: We present a few subjects from physics that have one in common: the spectral resolution of the Laplacian.
Arithmetic quantum chaos of Maass waveforms
H. Then
Mathematics , 2003,
Abstract: We compute numerically eigenvalues and eigenfunctions of the quantum Hamiltonian that describes the quantum mechanics of a point particle moving freely in a particular three-dimensional hyperbolic space of finite volume and investigate the distribution of the eigenvalues.
Maass cusp forms for large eigenvalues
H. Then
Mathematics , 2003,
Abstract: We investigate the numerical computation of Maass cusp forms for the modular group corresponding to large eigenvalues. We present Fourier coefficients of two cusp forms whose eigenvalues exceed r=40000. These eigenvalues are the largest that have so far been found in the case of the modular group. They are larger than the 130millionth eigenvalue.
Static Electric-Spring and Nonlinear Oscillations  [PDF]
H. Sarafian
Journal of Electromagnetic Analysis and Applications (JEMAA) , 2010, DOI: 10.4236/jemaa.2010.22011
Abstract: The author designed a family of nonlinear static electric-springs. The nonlinear oscillations of a massively charged particle under the influence of one such spring are studied. The equation of motion of the spring-mass system is highly nonlinear. Utilizing Mathematica [1] the equation of motion is solved numerically. The kinematics of the particle namely, its position, velocity and acceleration as a function of time, are displayed in three separate phase diagrams. Energy of the oscillator is analyzed. The nonlinear motion of the charged particle is set into an actual three-dimensional setting and animated for a comprehensive understanding.
First Principles Studies on the Electronic Structure and Band Structure of Paraelectric SrTiO3 by Different Approximations  [PDF]
H. Salehi
Journal of Modern Physics (JMP) , 2011, DOI: 10.4236/jmp.2011.29111
Abstract: The electronic structure, energy band structure, total density of states (DOS) and electronic density of perovskite SrTiO3 in the cubic phase are calculated by the using full potential-linearized augmented plane wave (FP-LAPW) method in the framework density functional theory (DFT) with the generalized gradient approximation (GGA) by WIEN2k package. The calculated band structure shows a direct band gap of 2.5 eV at the Γ point in the Brillouin zone.The total DOS is compared with experimental x-ray photoemission spectra. From the DOS analysis, as well as charge-density studies, I have conclude that the bonding between Sr and TiO2 is mainly ionic and that the TiO2 entities bond covalently.The calculated band structure and density of state of SrTiO3 are in good agreement with theoretical and experimental results.
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