Conventional Tillage versus No-till: Characteristics of Producers and Farms

A survey of Oklahoma farmers was conducted to determine characteristics of farms across three tillage categories: conventional tillage exclusively; no-till exclusively; other (combination of systems). The seven percent that use no-till exclusively crop more acres, rent more acres, and use more crop rotations than farms that use conventional tillage exclusively.no-till, conventional tillage, survey, farm machinery, farm size, wheat, perceptions, Crop Production/Industries, Farm Management, Q10, Q12,

Weak Isospin Violations in Charged and Neutral Higgs Couplings from SUSY Loop Corrections

Supersymmetric QCD and supersymmetric electroweak loop corrections to the violations of weak isospin to Yukawa couplings are investigated. Specifically it involves an analysis of the supersymmetric loop corrections to the Higgs couplings to the third generation quarks and leptons. Here we analyze the SUSY loop corrections to the charged Higgs couplings which are then compared with the supersymmetric loop corrections to the neutral Higgs couplings previously computed. It is found that the weak isospin violations can be quite significant, i.e, as much as 40-50% or more of the total loop correction to the Yukawa coupling. The effects of CP phases are also studied and it is found that these effects can either enhance or suppress the weak isospin violations. We also investigate the weak isospin violation effects on the branching ratio $BR(H^-\to\bar t b)/ BR(H^-\to \bar\nu_{\tau}\tau^-)$ and show that the effects are sensitive to CP phases. Thus an accurate measurement of this branching ratio along with the branching ratio of the neutral Higgs boson decays can provide a measure of weak isospin violation along with providing a clue to the presence of supersymmetry.Comment: 20 pages, 9 figure

Les pratiques paysannes de regeneration naturelle assistee des arbustes favorisent le developpement des champignons mycorhiziens arbusculaires

Dans les pays sahéliens en général et au Niger en particulier, la technique de la régénération naturelle assistée (RNA) est une pratique que les paysans utilisent pour recréer un système agroforestier. Ce travail a pour objectif principal d’évaluer l’impact de la RNA sur le potentiel mycorhizogène des sols dans le terroir de Dan Saga. La technique mise en œuvre a consisté à prélever des échantillons de sol et des racines fines à 1 m, 3 m et 5 m à partir du tronc des arbustes sur trois demi-cercles concentriques et à une profondeur de 20 - 40 cm dans les champs où la RNA est pratiquée. Des prélèvements de sol ont également été faits dans des placettes de 1m2 à la même profondeur en plein champ cultivé. L’analyse au laboratoire a porté sur des paramètres de la mycorhization à savoir la fréquence de la colonisation mycorhizienne, l’intensité de la colonisation du cortex racinaire, l’intensité de la colonisation développée dans la partie mycorhizée du système racinaire et la teneur en arbuscules. La densité sporale des sols et une identification morphologique des spores ont également été effectuées. Les résultats révèlent une réelle diversité de morphotypes de spores de champignons gloméromycètes dans les champs RNA. Il ressort de cette étude que la fréquence de mycorhization est plus élevée pour la RNA de 10 ans et plus faible pour celle de 3 ans et le témoin. Quant à l’intensité de mycorhization, elle est aussi plus importante dans la RNA de 10 ans et faible pour celle de 3 ans et le site sans RNA ou témoin. Par ailleurs, la densité sporale est plus importante dans les sols RNA que dans les sols sans RNA. La RNA favorise ainsi une installation et un développement de l’activité symbiotique mycorhizienne dans les champs cultivés.Mots clés : Pratiques paysannes, RNA, mycorhizes, sahel, Niger.  Farming management natural regeneration practices of shrubs promote the development of arbuscular mycorrhizal fungiFarming Management Natural Regeneration of trees (FMNR) in farmers’ field is one of the methods which farmers used in the re-greening process of their fields. This work was undertaken to evaluate the influence of FMNR on the soil richness in vesicular arbuscular mycorrhizal fungi (AMF) in Dan Saga cultivated lands. The method used was to collect soil samples in farmers field practicing FMNR for 3, 5 and 10 years agoand roots of shrubs at distances of 1 m, 3 m and 5m from the tree trunk at 20-40 cm depth. In roots mycorrhization evaluation, the Trouvelot’s method was used and the counting of spores was done with a binocular magnifying glass. The results evidenced the diversity of AMF in the cultivated soils under FMNR. The most important frequency of mycorrhization is observed with FMNRfields of 10 years old and the lowest frequency with that of 3 years old compared to the control. The intensity of mycorrhization was higher with FMNRof 10 yearsold and lower with that of 3 years old compared to the control. The Farming Management Natural Regeneration of trees favored installation and development of mycorrhizal activity in the cultivated farms. Keywords : Farmers practices, farming management natural regeneration, mycorrhizes, Sahel, Niger

CP-odd Phase Correlations and Electric Dipole Moments

We revisit the constraints imposed by electric dipole moments (EDMs) of nucleons and heavy atoms on new CP-violating sources within supersymmetric theories. We point out that certain two-loop renormalization group corrections induce significant mixing between the basis-invariant CP-odd phases. In the framework of the constrained minimal supersymmetric standard model (CMSSM), the CP-odd invariant related to the soft trilinear A-phase at the GUT scale, theta_A, induces non-trivial and distinct CP-odd phases for the three gaugino masses at the weak scale. The latter give one-loop contributions to EDMs enhanced by tan beta, and can provide the dominant contribution to the electron EDM induced by theta_A. We perform a detailed analysis of the EDM constraints within the CMSSM, exhibiting the reach, in terms of sparticle spectra, which may be obtained assuming generic phases, as well as the limits on the CP-odd phases for some specific parameter points where detailed phenomenological studies are available. We also illustrate how this reach will expand with results from the next generation of experiments which are currently in development.Comment: 31 pages, 21 eps figures; v2: additional remarks on 2-loop threshold corrections and references added; v3: typos corrected, to appear in Phys. Rev.

Large evolution of the bilinear Higgs coupling parameter in SUSY models and reduction of phase sensitivity

The phases in a generic low-energy supersymmetric model are severely constrained by the experimental upper bounds on the electric dipole moments of the electron and the neutron. Coupled with the requirement of radiative electroweak symmetry breaking, this results in a large degree of fine tuning of the phase parameters at the unification scale. In supergravity type models, this corresponds to very highly tuned values for the phases of the bilinear Higgs coupling parameter $B$ and the universal trilinear coupling $A_0$. We identify a cancellation/enhancement mechanism associated with the renormalization group evolution of $B$, which, in turn, reduces such fine-tuning quite appreciably without taking recourse to very large masses for the supersymmetric partners. We find a significant amount of reduction of this fine-tuning in nonuniversal gaugino mass models that do not introduce any new phases.Comment: Version to appear in Phys.Rev.D. Insignificant changes like a few typos corrected. 26 pages, 7 figures, LaTe

Diagnosis of Combination Faults in a Planetary Gearbox using a Modulation Signal Bispectrum based Sideband Estimator

This paper presents a novel method for diagnosing combination faults in planetary gearboxes. Vibration signals measured on the gearbox housing exhibit complicated characteristics because of multiple modulations of concurrent excitation sources, signal paths and noise. To separate these modulations accurately, a modulation signal bispectrum based sideband estimator (MSB-SE) developed recently is used to achieve a sparse representation for the complicated signal contents, which allows effective enhancement of various sidebands for accurate diagnostic information. Applying the proposed method to diagnose an industrial planetary gearbox which coexists both bearing faults and gear faults shows that the different severities of the faults can be separated reliably under different load conditions, confirming the superior performance of this MSB-SE based diagnosis scheme