Non-Linear Sigma Models on a Half Plane

In the context of integrable field theory with boundary, the integrable non-linear sigma models in two dimensions, for example, the $O(N)$, the principal chiral, the ${\rm CP}^{N-1}$ and the complex Grassmannian sigma models are discussed on a half plane. In contrast to the well known cases of sine-Gordon, non-linear Schr\"odinger and affine Toda field theories, these non-linear sigma models in two dimensions are not classically integrable if restricted on a half plane. It is shown that the infinite set of non-local charges characterising the integrability on the whole plane is not conserved for the free (Neumann) boundary condition. If we require that these non-local charges to be conserved, then the solutions become trivial.Comment: 25 pages, latex, no figure

Blood Biochemical Components and Progesterone Hormone on Day of Estrus in Crossbred Cattle in Egypt

Deficiencies or excess minerals such as P, Cu, and Zn are associated with subnormal fertility and anoestrus conditions in cows. This study was conducted in a veterinary unit in Menufiya, Egypt.  Eighteen head of crossbred cows were randomly selected at random at estrus time (estrus group) and as a control 14 head of crossbred cows were selected from newly-calving dams at about 6-12 hours after calving (control group). The aim of this study was to use the components of biochemistry and progesterone hormone on estrus day of crossbreeding cattle in Egypt.  The information from this study will be used to confirm estrus time to improve mating percentage. In blood plasma, the concentrations of all biochemical components and progesterone concentrations in estrus animals are higher than control cows except globulin. The results showed that blood plasma from control animal obtained Mg, Ca / P ratio, Co, Cu, Zn, Se, and Mo concentration is higher than estrus cattle. On the other hand, blood plasma concentrations of Na, K, Ca, P, Mn, and Fe are higher in estrus cattle. The progesterone concentration of estrus cattle is lower during summer than in winter. In estrus cows, higher plasma macro-elements were found in winter than in summer except for K, Ca and Ca/P ratio.  On the other side of estrus cattle, all trace elements of blood plasma are higher in winter than in summer except Zn, Mn, Se, and Fe

ANALISIS FAKTOR-FAKTOR YANG MEMPENGARUHI CADANGAN DEVISA INDONESIA PERIODE 1999-2013

ABSTRAK Perekonomian Indonesia saat ini sudah tidak dapat terpisahkan lagi dengan perekonomian dunia. Hal ini terjadi setelah dianutnya sistem perekonomian terbuka yang dalam aktivitasnya selalu berhubungan dan tidak lepas dari fenomena hubungan internasional. Adanya keterbukaan perekonomian ini berdampak pada perkembangan neraca pembayaran suatu negara yang meliputi arus perdagangan dan lalu lintas modal luar negeri suatu negara. Salah satu bentuk aliran modal yang masuk ke dalam negeri yaitu dapat berupa devisa yang berasal dari perdagangan internasional yang dilakukan oleh negara tersebut. Meningkatnya ekspor suatu negara akan membawa keuntungan yaitu kenaikan pendapatan, kenaikan devisa, transfer modal dan makin banyaknya kesempatan kerja. Penelitian ini bertujuan untuk mengkaji sejauh mana variabel-variabel bebas seperti laju pertumbuhan ekonomi, kurs, utang luar negeri dan ekspor berpengaruh terhadap cadangan devisa Indonesia Tahun 1999-2013. Metode analisis yang digunakan adalah Ordinary Least Square (OLS) dengan metode analisis linear berganda diregresi menggunakan E-Views 6. Dalam penelitian ini, dibuktikan dengan uji-F, bahwa variabel laju pertumbuhan ekonomi Indonesia, nilai tukar/kurs, utang luar negeri, dan ekspor secara bersama-sama berpengaruh secara signifikan terhadap cadangan devisa Indonesia. Berdasarkan uji-t, secara parsial, variabel laju pertumbuhan ekonomi Indonesia memiliki hubungan negatif dan tidak signifikan, nilai tukar (kurs) memiliki hubungan negatif dan signifikan terhadap cadangan devisa Indonesia. Utang luar negeri dan ekspor berpengaruh positif dan signifikan terhadap cadangan devisa Indonesia. Kata Kunci : Cadangan Devisa Indonesia, Laju Pertumbuhan Ekonomi, Nilai Tukar (Kurs), Utang Luar Negeri, dan Ekspor

Sensitivity of mixing layers to three-dimensional forcing

It is well known that turbulent mixing layers are dominated by large scale, fairly coherent structures, and that these structures are related to the stability characteristics of the flow. These facts have led researchers to attempt controlling such flows by selectively forcing certain unstable modes, which can in addition have the effect of suppressing other modes. Much of the work on controlling the mixing layer has relied on forcing 2-D instabilities. The results of forcing 3-D instabilities are addressed. The objectives of the work are twofold: to understand how a mixing layer responds to 3-D perturbations, and to test the validity of an amplitude expansion in predicting the mixing layer development. The amplitude expansion could be very useful in understanding and predicting the 3-D response of the flow to a variety of initial conditions

Theory of band gap bowing of disordered substitutional II-VI and III-V semiconductor alloys

For a wide class of technologically relevant compound III-V and II-VI semiconductor materials AC and BC mixed crystals (alloys) of the type A(x)B(1-x)C can be realized. As the electronic properties like the bulk band gap vary continuously with x, any band gap in between that of the pure AC and BC systems can be obtained by choosing the appropriate concentration x, granted that the respective ratio is miscible and thermodynamically stable. In most cases the band gap does not vary linearly with x, but a pronounced bowing behavior as a function of the concentration is observed. In this paper we show that the electronic properties of such A(x)B(1-x)C semiconductors and, in particular, the band gap bowing can well be described and understood starting from empirical tight binding models for the pure AC and BC systems. The electronic properties of the A(x)B(1-x)C system can be described by choosing the tight-binding parameters of the AC or BC system with probabilities x and 1-x, respectively. We demonstrate this by exact diagonalization of finite but large supercells and by means of calculations within the established coherent potential approximation (CPA). We apply this treatment to the II-VI system Cd(x)Zn(1-x)Se, to the III-V system In(x)Ga(1-x)As and to the III-nitride system Ga(x)Al(1-x)N.Comment: 14 pages, 10 figure

Solutions of multigravity theories and discretized brane worlds

We determine solutions to 5D Einstein gravity with a discrete fifth dimension. The properties of the solutions depend on the discretization scheme we use and some of them have no continuum counterpart. In particular, we find that the neglect of the lapse field (along the discretized direction) gives rise to Randall-Sundrum type metric with a negative tension brane. However, no brane source is required. We show that this result is robust under changes in the discretization scheme. The inclusion of the lapse field gives rise to solutions whose continuum limit is gauge fixed by the discretization scheme. We find however one particular scheme which leads to an undetermined lapse reflecting the reparametrization invariance of the continuum theory. We also find other solutions, with no continuum counterpart with changes in the metric signature or avoidance of singularity. We show that the models allow a continuous mass spectrum for the gravitons with an effective 4D interaction at small scales. We also discuss some cosmological solutions.Comment: 19 page