in this study, yield-water and profit function was used to obtain water demand function in agriculture sector. the results showed that the ratio of actual to potential evapotranspiration had positive, significant effecton the ratio of actual to potential yield for wheat and barley. also, square ratio of actual to potential evapotranspiration had negative, significant relationship. after estimat...

In this note, we obtain a sharp volume estimate for complete gradient Ricci solitons with scalar curvature bounded below by a positive constant. Using Chen-Yokota’s argument we obtain a local lower bound estimate of the scalar curvature for the Ricci flow on complete manifolds. Consequently, one has a sharp estimate of the scalar curvature for expanding Ricci solitons; we also provide a direct ...

In this paper, by modifying Cheng-Yau$'$s technique to complete hypersurfaces in $S^{n+1}(1)$, we prove a rigidity theorem under the hypothesis of the mean curvature and the normalized scalar curvature being linearly related which improve the result of [H. Li, Hypersurfaces with constant scalar curvature in space forms, {em Math. Ann.} {305} (1996), 665--672].  

Abstract Scalar field cosmologies with a generalized harmonic potential are investigated in flat and negatively curved Friedmann–Lemaître–Robertson–Walker Bianchi I metrics. An interaction between the scalar matter is considered. Asymptotic methods averaging theory used to obtain relevant information about solution space. In this approach, Hubble parameter plays role of time-dependent perturbat...

It is shown that an arbitrary static, spherically symmetric metric can be presented as exact solution of a scalar-tensor theory (STT) gravity with certain nonminimal coupling function $f(\phi)$ and potential $U(\phi)$. The scalar field in this representation change its nature from canonical to phantom on coordinate spheres. This representation, however, valid general not the full range radial b...

We propose an Einstein-æther scalar–tensor cosmological model. In particular, in the Action Integral, we introduce æther field with coefficients to be functions of scalar field. This model extends previous studies on Lorentz-violating theories. For a spatially flat Friedmann–Lemaître–Robertson–Walker background space, write equations which are second order dynamical variables scale factor and T...

Born-Infeld black holes in the Scalar-Tensor Theories of Gravity, in the case of massless scalar field, have been recently obtained [1, 2, 3]. The aim of the current paper is to study the effect from the inclusion of a potential for the scalar field in the theory, through a combination of analytical techniques and numerical methods. The black holes coupled to a massive scalar field have richer ...