Abstract The subject of harmonic and biharmonic submanifolds, with important role in mathematical physics and differential geometry, arises from the variation problems of ordinary mean curvature vector field. Generally, harmonic submanifolds are biharmonic, but not vice versa. Of course, many examples of biharmonic hypersurfaces are harmonic. A well-known conjecture of Bang-Yen Chen on Euclidean spaces says that every biharmonic submanifold is harmonic. Although the conjecture has not been proven (in general case), it has been affirmed in many cases, and this has led to its spread to various types of submanifolds. Inspired by the conjecture, we study the Lorentz submanifolds of the Lorentz-Minkowski spaces. We consider an advanced versión of the conjecture (namely, L1-conjecture) on Lorentz hypersurfaces of the pseudo-Euclidean 5-space L 5: = E 1 5 (i.e. the Minkowski 5-space). We confirm the extended conjecture on Lorentz hypersurfaces with three principal curvatures.

ABSTRACT The aim of this study was to investigate the effects of different dietary levels of L-arginine on the growth performance, blood parameters, and lipogenic gene expression of Arian broiler chickens. For this purpose, 168 Arian broiler chicks (40.33±1.7 g) were assigned to four treatments with three replicates of14 birds each, according to completely randomized design. The experimental treatments consisted of 100, 124, 139, and 154% dietary arginine levels relative to the published requirements of Arian broilers. On 42 d of the experiment, blood samples were collected from two birds (six birds per treatment) for blood metabolite measurements. These birds were then euthanized for carcass evaluation and collection of tissue samples. Increasing dietary arginine levels reduced (p<0.05) the gene expression of fatty acid synthase, acetyl-coenzyme A carboxylase, and malic enzyme in the liver and lipoprotein lipase in the abdominal fat tissue, as well as abdominal fat relative weight. Increasing dietary arginine levels significantly increased (p<0.05) body weight, feed efficiency, carcass yield, breast and thigh relative weights, and glucose and HDL (high-density lipoprotein) blood levels, and reduced cholesterol, triglyceride, and LDL (low-density lipoprotein) blood levels. Since almost similar performance and carcass trait results were obtained both with 124 and 139% arginine levels, supplying Arian broiler diets with 124% arginine is suggested.

A two-way factorial experiment based on a randomized complete design (RCD) with four replications was used to compare four levels of N supply including control (N0), 60(N60), 120(N120) and 180(N180) mg N per Kg soil and four different water supply including 100(I100), 80(I80), 60(I60) and 40(I40) % FC on growth, water-use efficiency and mucilage yield of isabgol. Under I40, higher N addition led to a significant decrease in root and shoot DM. N addition increased root and shoot biomass especially in I80 treatment followed by I60. The highest (1.71 g plant-1) and the lowest (0.42 g plant-1) seed yield of isabgol observed in I100 at N120 and I40 at N120 respectively. The concentration of soluble sugar increased with N supply at I100 and I40. Water stress led to an increase in proline levels, particularly in the N supply treatments. The addition of N tended to reduce the positive effect of water stress on proline content. Seed water use efficiency (WUEg) of isabgol decreased with the increase in drought stress. N supply significantly increased WUEg from N0 to N120 with no significant differences between N60 and N120 and then significantly decreased by supplying N180. Mucillage water use efficiency (WUEm) is also increased linear in all watering regime at all N supply.