On non-minimal N=4 supermultiplets in 1D and their associated sigma-models

We construct the non-minimal linear representations of the N=4 Extended Supersymmetry in one-dimension. They act on 8 bosonic and 8 fermionic fields. Inequivalent representations are specified by the mass-dimension of the fields and the connectivity of the associated graphs. The oxidation to minimal N=5 linear representations is given. Two types of N=4 sigma-models based on non-minimal representations are obtained: the resulting off-shell actions are either manifestly invariant or depend on a constrained prepotential. The connectivity properties of the graphs play a decisive role in discriminating inequivalent actions. These results find application in partial breaking of supersymmetric theories.Comment: 24 pages, 6 figure

Interações entre o sexo do bezerro e outros fatores ambientais para pesos do nascimento aos 24 meses em bovinos da raça Charolesa.

Interações entre o sexo do bezerro e outros fatores ambientais para pesos do nascimento aos 24 meses em bovinos da raça Charolesa

Gauging N=4 supersymmetric mechanics II: (1,4,3) models from the (4,4,0) ones

Exploiting the gauging procedure developed by us in hep-th/0605211, we study the relationships between the models of N=4 mechanics based on the off-shell multiplets (4,4,0) and (1,4,3). We make use of the off-shell N=4, d=1 harmonic superspace approach as most adequate for treating this circle of problems. We show that the most general sigma-model type superfield action of the multiplet (1,4,3) can be obtained in a few non-equivalent ways from the (4,4,0) actions invariant under certain three-parameter symmetries, through gauging the latter by the appropriate non-propagating gauge multiplets. We discuss in detail the gauging of both the Pauli-Gursey SU(2) symmetry and the abelian three-generator shift symmetry. We reveal the (4,4,0) origin of the known mechanisms of generating potential terms for the multiplet (1,4,3), as well as of its superconformal properties. A new description of this multiplet in terms of unconstrained harmonic analytic gauge superfield is proposed. It suggests, in particular, a novel mechanism of generating the (1,4,3) potential terms via coupling to the fermionic off-shell N=4 multiplet (0,4,4).Comment: 27 page

Seasonal variability of Indonesian rainfall in ECHAM4 simulations and in the reanalyses: The role of ENSO

A study on the skill of the atmospheric general circulation model ECHAM version 4 and two reanalyses in simulating the Indonesian rainfall is presented with comparisons to 30 years of rain gauge data. The reanalyses are those performed by the European Centre for Medium-Range Weather Forecasts and of the National Centers for Environmental Predic- tion jointly with National Center for Atmospheric Research. This study investigates the skill of the reanalyses and ECHAM4 with regard to regional, annual and interannual variability of rainfall and its responses to El Ni˜ no-Southern Oscillation (ENSO) events. The study is conducted at two resolutions, T42 and T106. A new regionalization method called the double correlation method is introduced. With this method, the Maritime Continent is divided into three climate regions, the south mon- soonal, the northwest semi-monsoonal and the Molucca anti-monsoonal region. Except over Molucca, the reanalyses and ECHAM4 simulate these annual rainfall patterns quite well. The three regions are used to study the variability of Indonesian rainfall and to mea- sure the skills of the reanalyses and ECHAM4. The skill of rainfall simulations in Indonesia depends on the region, month and season, and the distribution of land and sea. Higher sim- ulation skills are confined to years with ENSO events. Except for the region of northwest Indonesia, the rainfall from June (Molucca) and July (south Indonesia) to November is in- fluenced by ENSO, and it is more sensitive to El Ni˜ no than La Ni˜ na events. The observations show that the Moluccan region is more sensitive to ENSO, receives a longer ENSO impact and receives the earliest ENSO impact in June. The ENSO impact will diminish in Decem- ber. It is found that the reanalyses and the climate model simulate the seasonal variability better than the monthly one. The seasonal skill is the highest in June/July/August, followed by September/October/November, December/January/February and March/April/May. The correlations usually break down in April (for monthly analysis) or in spring (for seasonal analysis). In general the performance of ECHAM4 is poor, but in ENSO sensitive regions and during ENSO events, it is comparable to the reanalyses. The introduction of a higher resolution land-sea mask improves the model performance. Besides rainfall variability, signatures of the ENSO impact, the spring correlation breakdown and annual cycles are better represented by the higher resolution model

Gauging N=4 Supersymmetric Mechanics

We argue that off-shell dualities between d=1 supermultiplets with different sets of physical bosonic components and the same number of fermionic ones are related to gauging some symmetries in the actions of the supermultiplets with maximal sets of physical bosons. Our gauging procedure uses off-shell superfields and so is manifestly supersymmetric. We focus on N=4 supersymmetric mechanics and show that various actions of the multiplet (3,4,1) amount to some gauge choices in the gauged superfield actions of the linear or nonlinear (4,4,0) multiplets. In particular, the conformally invariant (3,4,1) superpotential is generated by the Fayet-Iliopoulos term of the gauge superfield. We find a new nonlinear variant of the multiplet (4,4,0), such that its simplest superfield action produces the most general 4-dim hyper-K\"ahler metric with one triholomorphic isometry as the bosonic target metric. We also elaborate on some other instructive examples of N=4 superfield gaugings, including a non-abelian gauging which relates the free linear (4,4,0) multiplet to a self-interacting (1,4,3) multiplet.Comment: 32 pages, minor amendments in Sect. 2, version to appear in Nucl. Phys.

Embedding (R+R^2)-Inflation into Supergravity

We find the natural embedding of the (R+R^2)-inflationary model into the recently constructed N=1 F(\cal R)-supergravity. It gives a simple and viable realization of chaotic inflation in supergravity. The only requirement for a slow-roll inflation is the existence of the (\cal R)^3-term with an anomalously large coefficient in Taylor expansion of the F(\cal R) function, where \cal R is the covariantly-chiral scalar supercurvature superfield.Comment: 4 pages, revtex, no figures (very minor additions, a reference added

Worldsheet Matter Superfields on Half-Shell

In this paper we discuss some of the effects of using "unidexterous" worldsheet superfields, which satisfy worldsheet differential constraints and so are partly on-shell, i.e., on half-shell. Most notably, this results in a stratification of the field space that reminds of "brane-world" geometries. Linear dependence on such superfields provides a worldsheet generalization of the super-Zeeman effect. In turn, non-linear dependence yields additional left-right asymmetric dynamical constraints on the propagating fields, again in a stratified fashion.Comment: 15 pages, 2 figures; minor algebraic correction

The Common Origin of Linear and Nonlinear Chiral Multiplets in N=4 Mechanics

Elaborating on previous work (hep-th/0605211, hep-th/0611247), we show how the linear and nonlinear chiral multiplets of N=4 supersymmetric mechanics with the off-shell content (2,4,2) can be obtained by gauging three distinct two-parameter isometries of the ``root'' (4,4,0) multiplet actions. In particular, two different gauge groups, one abelian and one non-abelian, lead, albeit in a disguised form in the second case, to the same (unique) nonlinear chiral multiplet. This provides an evidence that no other nonlinear chiral N=4 multiplets exist. General sigma model type actions are discussed, together with the restricted potential terms coming from the Fayet-Iliopoulos terms associated with abelian gauge superfields. As in our previous work, we use the manifestly supersymmetric language of N=4, d=1 harmonic superspace. A novel point is the necessity to use in parallel the \lambda and \tau gauge frames, with the ``bridges'' between these two frames playing a crucial role. It is the N=4 harmonic analyticity which, though being non-manifest in the \tau frame, gives rise to both linear and nonlinear chirality constraints.Comment: 22 pages, Latex, minor corrections, to appear in Nucl. Phys.

Genetic Improvement of Bermudagrass for Hay Producers

Bermudagrass (Cynodon spp.) is considered the most valuable warm-season perennial grass for hay producers in the Southeastern United States. Bermudagrass genotypes have overall good forage quality, high yields, and store well. However, there are challenges to producing good hay for the market. First, early green-up in the spring is needed to allow for four to five productive clippings during the summer. When first establishing production fields, quick emergence and cover are important for reducing weeds. Forage bermudagrass is somewhat tolerant to drought, however, low rainfall substantially reduces yields. If rainfall is too abundant, it is difficult to have timely curing in the field for baling. This is especially true for the higher quality thick-stemmed cultivars such as Tifton 85. More recently, the bermudagrass stem maggot (BSM, Atherigona reversura) has caused yield reductions and reduced net income for hay producers. Plant breeding has attempted to address all these issues. This talk will highlight some areas of research that has been done over the past few decades to improve bermudagrass for hay production

V,W and X in Technicolour Models

Light techni-fermions and pseudo Goldstone bosons that contribute to the electroweak radiative correction parameters V,W and X may relax the constraints on technicolour models from the experimental values of the parameters S and T. Order of magnitude estimates of the contributions to V,W and X from light techni-leptons are made when the the techni-neutrino has a small Dirac mass or a large Majorana mass. The contributions to V,W and X from pseudo Goldstone bosons are calculated in a gauged chiral Lagrangian. Estimates of V,W and X in one family technicolour models suggest that the upper bounds on S and T should be relaxed by between 0.1 and 1 depending upon the precise particle spectrum.Comment: 19 pages + 2 pages of ps figs, SWAT/1