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We show that in a reaction diffusion system on a two-dimensional substrate with advection in the confined direction, the drift (advection) induced instability occurs through a Hopf bifurcation, which can become a double Hopf bifurcation. The box size in the direction of the drift is a vital parameter. Our analysis involves reduction to a low dimensional dynamical system and constructing amplitude equations. [ABSTRACT FROM AUTHOR]

We investigate a population-imbalanced two-species fermionic system where the resonantly paired fermions combine to form bosonic molecules via Feshbach interaction. We study the dynamics of the intrinsic quantum fluctuations of the system. It is shown that the natural fluctuations of the condensate fraction consist of a fixed number of periodic components: indicating that these oscillations do not die out, and are sustained in the mean field dynamics of the system. These frequency components bear distinct signatures of the nature of pairing present in the system. We describe how a time-dependent external magnetic field can be used to locate these oscillation frequencies, and thus to explore the momentum space structure of the population imbalanced system. We propose that this method can be used as an indirect experimental probe for detecting exotic phases like the breached-pair state, FFLO state, and a phase-separated state comprising of BCS and normal regions. [ABSTRACT FROM AUTHOR]

This communication reports the successful adsorption of a water-soluble cationic fluorescent dye Acridine Orange (AO) onto Langmuir–Blodgett (LB) films of a cationic amphiphile octadecylamine (ODA) in the presence of nano-clay platelets hectorite. Acridine orange (AO) has been widely used as a stainer for the characterization of biopolymers. But AO has a tendency to form non-florescent H-dimer even in the aqueous solution. Anionic nano-clay platelets hectorite played an important role in controlling the H-dimer formation of AO in the hybrid film. Effects of various parameters in the adsorption process were investigated in detail. [ABSTRACT FROM AUTHOR]

Porphyrins have a general tendency to form aggregates in ultrathin films. Also electrostatic adsorption of cationic porphyrins onto anionic nano clay platelets results in the flattening of porphyrin moieties. The flattening is evidenced by the red-shifting of Soret band with respect to the aqueous solution. In the present communication, we have studied the clay induced aggregation behaviour of a tetra-cationic metalloporphyrin Manganese (III) 5, 10, 15, 20-tetra (4 pyridyl)-21 H, 23 H-porphine chloride tetrakis (methochloride) (MnTMPyP) in Layer-by-Layer (LbL) self assembled film. The adsorption of dye molecules onto nano clay platelets resulted in the flattening of the meso substituent groups of the dye chromophore. In Layer-by-Layer ultrathin film, the flattened porphyrin molecules tagged nano clay platelets were further associated to form porphyrin aggregates. This has been clearly demonstrated from the UV–vis absorption spectroscopic studies. Atomic Force Microscopic (AFM) studies gave visual evidence of the association of organo-clay hybrid molecules in the LbL film. [ABSTRACT FROM AUTHOR]

In the present communication, interaction of tetracationic porphyrin, 5,10,15,10-tetrakis (1-methyl-4-pyrindino) porphyrin tetra (p-toluenesulfonate) (TMPyP) with anionic nano clay platelets laponite has been studied in aqueous clay dispersion and Layer-by-Layer (LbL) self assembled film. Electrostatic adsorption of TMPyP molecules on clay platelets resulted in the flattenening of meso-substituent groups which led to the development of a new adsorbed band in the UV–vis absorption spectra. J-band was also formed due to overlapped organizations of organo-clay hybrid molecules in the LbL film leading to J-aggregates. Atomic force microscopic (AFM) studies gave visual evidence of this favoured organization in the monolayer LbL film. [ABSTRACT FROM AUTHOR]

Generation of flexural gravity waves in a two-layer fluid due to the forced motion of a vertical rigid wavemaker is studied in both finite and infinite water depths. The twodimensional (2D) fluid domain having an interface is covered by a semi-infinite ice sheet, which is modeled as an elastic beam. As an application of the wavemaker problem, flexural gravity wave reflection by a vertical cliff is analyzed. Under the assumptions of small amplitude water wave theory and structural response, the mathematical models are solved using a recently developed expansion formulae and the associated orthogonal mode-coupling relations as appropriate fo r finite and infinite water depths. Effect of three types of edges such as free edge, simply supported edge, and built-in edge on the wave reflection by the vertical cliff is analyzed whilst, for the wavemaker, the floating ice sheet is assumed to have free edge. Effect of various physical parameters on the wave motion is studied by analyzing the reflection coefficients, deflection of the ice sheet, interface elevation, strain and shear force on the floating ice sheet. [ABSTRACT FROM AUTHOR]

The effect on the efficiency of the device of implementing a dual-chamber oscillating water column (OWC) placed over stepped bottom is analysed. The mathematical problem is formulated in the two dimensional Cartesian coordinate system under the linear water wave theory. Two different mathematical approaches are adopted to solve the associated boundary value problem (BVP), one is the method of matched eigenfunction expansion and the other is the boundary integral equation method (BIEM). The numerical results show good agreement with the analytical results. The performance of the proposed device is analysed and compared with the typical single chamber OWCs with/without step and with dual-chamber OWCs over uniform bottom profile. The present investigation shows that by considering dual-chamber OWC device on the stepped sea bottom the performance of the device can be improved significantly in wide range of frequencies, as compared with the single chamber case. [ABSTRACT FROM AUTHOR]

Combined effects of current and surface tension on time-dependent transient boundary value problems (BVPs) associated with capillary-gravity wave motion in a two-layer fluid are analyzed under the assumption of small amplitude water wave theory in three dimensions. Plane wave solutions are discussed by analyzing the roots of the dispersion relation and phase velocity. Using the Laplace transform technique and Green's function method, the time-dependent initial boundary value problem (IBVP) for the capillary-gravity wave motion are analyzed in both the cases of finite and infinite water depths. Using the method of stationary phase, the time-dependent Green's function and surface and interface profiles are computed and analyzed for various values of physical parameters in two different cases. The time harmonic solutions are obtained as one of the special cases of the time-dependent IBVP in both the cases of finite and infinite water depths. It is observed that the direction of current and wave changes the phase velocity of the capillary-gravity wave motion along with the free surface and interface elevations. The position of the source significantly changes the amplitude of the source potentials in surface and internal modes. Further, the location of the interface has a significant influence on the pattern of surface and interface elevations. [ABSTRACT FROM AUTHOR]

Oxazine 4 perchlorate (OX4) forms dimer even in aqueous solution. In layer-by-layer (LbL) film of OX4, dimeric sites predominate over monomeric sites. This results in the quenching of fluorescence intensity. This communication reports a study of the control of H-dimer of OX4 in LbL film by incorporating nano clay platelets. Influence of deoxyribonucleic acid molecules in controlling the H-dimeric sites of Ox4 in the LbL film has also been studied. UV-Vis absorption spectroscopic technique has been employed to study this effect. Atomic force microscopic image confirms the presence of nano clay platelets in the LbL film. [ABSTRACT FROM AUTHOR]

Highlights: [•] Layer-by-layer (LbL) film of acridine orange. [•] Dimeric band of acridine orange predominates in LbL film. [•] Interaction of acridine orange with laponite clay in LbL film. [•] Controlling of dimeric band of acridine orange in LbL film. [ABSTRACT FROM AUTHOR]

Abstract: The present study analyses the role of stepped bottom topography in increasing the efficiency of a nearshore oscillating water column (OWC) device. The mathematical problem is formulated in the two dimensional Cartesian coordinate system under the linear water wave theory. Two different mathematical approaches are adopted to solve the associated boundary value problem (BVP), one is the method of matched eigenfunction expansion and the other is the boundary integral equation method (BIEM). The numerical results show good agreement with the analytical results. Three different horizontal positions of the step are considered. The effect of the distance of the step from the water column barrier and the height of the step on the efficiency of the OWC device are discussed in detail. The results show that inclusion of an artificial step at the sea bottom with proper tuning may lead to a significantly increased capacity of power absorption of the device. [Copyright &y& Elsevier]

Abstract: Interaction of surface gravity waves with multiple vertically moored surface-piercing membrane breakwaters in finite water depth is analyzed based on the linearized theory of water waves. The study is carried out using least square approximation method to understand the effect of the vertical membrane as effective breakwater. Initially the problem is studied for a single membrane wave barrier but for the case of multiple membrane breakwaters the study is carried out using the method of wide-spacing approximation. In the present study, it is observed that the deflection of the membrane is reduced with the increase in the stiffness parameter of the mooring lines attached to the membrane. In the case of single surface-piercing membrane with moored and fixed edge conditions, the reflection and transmission coefficients are compared and analyzed in detail. The resonating pattern in the reflection coefficients are also observed for multiple floating membrane which can also be referred as Bragg''s resonance. In the presence of the porosity constant the wave reflection is also observed to be decreasing and the change in the distance between the vertical floating breakwaters also helps in the attenuation of wave height. It is observed that the presence of multiple floating breakwater helps in the reduction of wave height in the transmitted region. [Copyright &y& Elsevier]

The Lindstedt-Poincare technique has traditionally been used to deal with oscillators with power-law potentials. We show how this method can be extended to deal with molecular potentials for which the frequency goes to zero as the energy approaches zero. The extension requires the use of an asymptotic analysis which is combined with perturbation theory. For the Morse potential, we get an exact answer while for the Lennard Jones class of potentials $${{\rm V}={\rm V}_0 \left[ {\left( {\frac{{a}}{{\rm x}}}\right)^{2{\rm n}}-\left({\frac{{\rm a}}{{\rm x}}}\right)^{{\rm n}}}\right]}$$ , the answer is generally approximate with some values of n giving exact results. For the widely studied case, n=6, our approximation gives better than 1% accuracy at the lowest order of calculation. We show that as $${{\rm n} \rightarrow \infty}$$ , the result tends to that for the Morse potential. We also point out that the time period obtained by us can be used to obtain the quantum mechanical energy levels of these potentials within the Bohr-Sommerfeld scheme. [ABSTRACT FROM AUTHOR]

Abstract: Nanocrystalline Mn doped Zn1−x Mn x O (x =0.02, 0.05, 0.07, 0.10) dilute magnetic semiconductors (DMSs) have been synthesized by mechanical alloying the stoichiometric mixtures of ZnO and MnO powders for different durations in a high energy planetary ball mill at room temperature under air medium. In the course of milling, the peak broadening of ZnO reflections increases continuously and MnO reflections disappear completely after 2h of milling. Microstructure characterization of ball milled samples employing the Rietveld structure refinement using X-ray diffraction data reveals that the Zn2+ ions are replaced by Mn2+ ions and lattice parameters of ZnO matrix increase slowly due to this substitution. Particle size of these DMS decreases continuously with increasing Mn concentrations. XPS measurement indicates that the doped Mn ions possess both Mn2+ and Mn4+ valance states. Magnetic characterization of DMS samples shows room temperature ferromagnetism (RTF), which confirms the inclusion of Mn2+ in ZnO lattice and the RTF can be explained in the light of RKKY exchange interaction. Optical characterization of these DMS by UV–vis spectroscopy clearly reveals a red-shift and consequently the optical band-gap decreases with increasing Mn concentrations. [Copyright &y& Elsevier]

Based on a representation of the sound velocity of critical liquids in terms of a frequency-dependent complex specific heat at constant pressure, a simple relation between the low-frequency normalized sonic attenuation coefficient and the correlation length of fluctuations is derived. This relation provides a promising alternative for the determination of the dynamics exponent and thus the critical exponent of the shear viscosity. Sonic attenuation data from the literature, measured at frequencies down to 50 kHz, are re-evaluated with a view of the viscosity exponent determination. It is found that only in a small temperature range, the major requirement of the approach is fulfilled with the available data. Close to the critical temperature, the frequencies of measurement are still insufficiently small as compared to the inverse relaxation time of order parameter fluctuations. Criteria for future experiments are discussed briefly. [ABSTRACT FROM AUTHOR]

Based on our studies done on two-dimensional autonomous systems, forced non-autonomous systems and time-delayed systems, we propose a unified methodology - that uses renormalization group theory - for finding out existence of periodic solutions in a plethora of nonlinear dynamical systems appearing across disciplines. The technique will be shown to have a non-trivial ability of classifying the solutions into limit cycles and periodic orbits surrounding a center. Moreover, the methodology has a definite advantage over linear stability analysis in analyzing centers. [ABSTRACT FROM AUTHOR]

Abstract: Diffraction of obliquely incident waves by a floating structure near a wall with step-type bottom topography is investigated under the three-dimensional small amplitude wave theory. Full solution of the problem under the potential flow approach is obtained by the matched eigenfunction expansion method. The wave-induced forces on the structure and on the wall, the reflection and transmission characteristics and the wave elevations in the free surface regions are studied for different incident wave angles, water depth ratios and dimension of the structure and the distance of the wall from the center of the structure. The problem is reformulated under shallow water approximations and results are compared with the finite depth results. [Copyright &y& Elsevier]

Motivated by recent advances in synthesis and characterization of carbon nanotube (CNT) heterojunctions, we introduce a systematic approach for obtaining atomic geometries that connect two carbon nanotubes of different chiralities. Using our approach, it is straightforward to construct atomic interface geometries between two single-walled CNT's of arbitrary chiralities arranged at different orientations and angles. Our method generalizes existing approaches and is readily applicable to joining domains of graphene nanoribbons as well. As an example, we focus on linear heterojunctions, and we postulate the minimum number of simple topological defects required at the interface, and the preferred spatial arrangements, to obtain maximally linear heterojunctions given any two arbitrary chiralities. We also provide a physical picture of the defect structure of the resultant interface geometries using the results of classical force-field simulations. [ABSTRACT FROM AUTHOR]

We consider the Sel'kov model of glycolytic oscillator for a quantitative study of the limit cycle oscillations in the system. We identify a region of parameter space where perturbation theory holds and use both Linstedt Poincaré technique and harmonic balance to obtain the shape and frequency of the limit cycle. The agreement with the numerically obtained result is excellent. We also find a different extreme, where the limit cycle is of the relaxation oscillator variety, has a large time period and it is seen that, as a particular parameter in the model is varied, the time period increases indefinitely. We characterize this divergence numerically. A calculational method is devised to capture the divergence approximately. [ABSTRACT FROM AUTHOR]

An exact calculation of the Casimir force for a non-interacting Bose gas confined between two parallel plates is presented. The gas can be free or trapped, parallel to the plates. Depending on the finite size parameter λ/L (λ is the de Bröglie wavelength and L is the separation of the plates) and the density parameter nλ3 (n, the number density), the Casimir force crosses over from a power law to an exponential fall off is clearly seen. Since the Casimir force measurement requires very small values of L, one needs to take into account of the condensation in a finite system. [ABSTRACT FROM AUTHOR]

Abstract: Flexural gravity wave scattering by multiple articulated floating elastic plates is investigated in the three cases for water of finite depth, infinite depth and shallow water approximation under the assumptions of two-dimensional linearized theory of water waves. The elastic plates are joined through connectors, which act as articulated joints. In the case when two semi-infinite plates are connected through a single articulation, using the symmetric characteristic of the plate geometry and the expansion formulae for wave-structure interaction problem, the velocity potentials are obtained in closed forms in the case of finite and infinite water depths. On the other hand, in the case of shallow water approximation, the continuity of energy and mass flux are used to obtain a system of equations for the determination of the full velocity potentials for wave scattering by multiple articulations. Further, using the results for single articulation and assuming that the articulated joints are wide apart, the wide-spacing approximation method is used to obtain the reflection coefficient for wave scattering due to multiple articulated floating elastic plates. The effects of the stiffness of the connectors, length of the elastic plates and water depth on the propagation of flexural gravity waves are investigated by analysing the reflection coefficient. [Copyright &y& Elsevier]

Abstract: In the present study, the effect of shear current on the propagation of flexural gravity waves is analyzed under the assumptions of linearized shallow-water theory. Explicit expressions for the reflection and transmission coefficients associated with flexural gravity wave scattering by a step discontinuity in both water depth and current speed are derived. Further, trapping and scattering of flexural gravity waves by a jet-like shear current with a top-hat profile are examined and certain limiting conditions for the waves to exist are derived. The effects of change in water depth, current speed, incident wavelength and the angle of incidence on the group and phase velocities as well as on the reflection and transmission characteristics are analyzed through different numerical results. [Copyright &y& Elsevier]

We find the energy levels of a free particle confined in a two dimensional infinite potential well having super-circular boundary (|x|n+|y|n=an where n is a rational number and a is a positive real number) by perturbing about the equivalent circle (n=2). The ground state energies are very accurate over a wide range of n and can be improved further by introducing a phenomenological constant determined from the knowledge of exact results available for diamond (n=1). For excited states, we find that the shape effect can cause parametric resonance which can lead to singlet-triplet crossing. [ABSTRACT FROM AUTHOR]

The motion of a spinning soccer ball brings forth the possible existence of a whole class of finite dynamical systems where there may be a nondenumerably infinite number of fixed points. They defy the very traditional meaning of the fixed point that a point on the fixed point in the phase space should remain there forever, for, a fixed point can evolve as well! Under such considerations one can argue that a free-kicked soccer ball should be nonchaotic. [ABSTRACT FROM AUTHOR]

Contents Shortening age at puberty of crossbred breeding bull is an important issue in the tropic. This study aimed at selecting crossbred bulls at earliest possible age with bigger scrotum and potential for donating quality semen. One hundred and 31 pre-joining crossbred bulls of Central Artificial Insemination Laboratory, Saver, Dhaka were examined. The bulls being trained by seeing semen collection from mature bulls were allowed ejaculation into the artificial vagina at homosexual mount during a 20 min time at three occasions, every three month. Eighty one of 131 bulls produced at least one ejaculate during the study and their mean ± SD age and scrotal circumference (SC) were 20.3 ± 4.7 months and 28.2 ±2.7 cm, respectively. Bulls’ body weight, body condition score (BCS) and SC influenced the attainment of their puberty (p < 0.05). Bull's body weight had positive effects on scrotal circumference and ejaculate volume (p < 0.05). Scrotal circumference positively influenced the percentages of normal spermatozoa (p < 0.05). Scrotal skin-fold thickness negatively influenced the proportion of spermatozoa with normal head (p < 0.05). Based on age at first ejaculate and SC, 29.6% bulls (n = 24) were selected by cluster analysis. Selected bulls had mean ± SD age 17.9 ± 2.2 months, body weight 287.3 ±48.6 kg, SC 30.5 ± 1.5 cm, ejaculate volume 3.4 ± 1.3 ml, sperm motility 50.8 ± 17.2%, total spermatozoa per ejaculate 2541.9 ± 1699.2 million and normal spermatozoa 81.5 ±14.5%. The selected pubertal bull group was different from the unselected pubertal bulls atmanova (p < 0.0001). About 30% of pubertal crossbred bulls can be selected with shorter age and larger scrotum at puberty under conditions prevailed in Bangladesh. [ABSTRACT FROM AUTHOR]

Abstract: The interaction between current and flexural gravity waves generated due to a floating elastic plate is analyzed in two dimensions under the assumptions of linearized theory. For plane flexural gravity waves, explicit expressions for the water particle dynamics and trajectory are derived. The effect of current on the wavelength, phase velocity and group velocity of the flexural gravity waves is analyzed. Variations in wavelength and wave height due to the changes in current speed and direction are analyzed. Effects of structural rigidity and water depth on wavelength are discussed in brief. Simple numerical computations are performed and presented graphically to explain most of the theoretical findings in a lucid manner. [Copyright &y& Elsevier]

We report here a sensitive and specific polymerase chain reaction (PCR) detection assay for the pathogenic Candida yeast based on the novel LYS1 [encoding saccharopine dehydrogenase (SDH)] and LYS5 [encoding phosphopantetheinyl transferase (PPTase)] gene sequences of the fungal unique lysine biosynthetic pathway. Both LYS1 and LYS5 DNA-specific PCR primers SG1, SG2 and SG3, SG4, respectively, amplified predicted 483 and 648-bp fragments from Candida albicans genomic DNA but not from other selected fungal, bacterial, or human DNA. The 18S rDNA control primers exhibited positive amplifications in all PCR assays. The LYS1-and LYS5-specific primers strongly amplified C. albicans and Candida tropicalis target sequences; however, the LYS1 primers also weakly amplified fragments from Candida kefyr and Candida lusitaniae DNA. Both sets of primers amplified target sequences from less than 10 pg of serially diluted C. albicans DNA, and the LYS1 specific primers also detected DNA isolated from serially diluted 50 C. albicans cells. The PCR primers reported here are sufficiently sensitive and specific for the potential early detection of Candida infections with no possibility of false positive results from cross-contamination with bacterial or human DNA. [ABSTRACT FROM AUTHOR]

In the presence of viscosity the hydraulic jump in one dimension is seen to be a first-order transition. A scaling relation for the position of the jump has been determined by applying an averaging technique on the stationary hydrodynamic equations. This gives a linear height profile before the jump, as well as a clear dependence of the magnitude of the jump on the outer boundary condition. The importance of viscosity in the jump formation has been convincingly established, and its physical basis has been understood by a time-dependent analysis of the flow equations. In doing so, a very close correspondence has been revealed between a perturbation equation for the flow rate and the metric of an acoustic white hole. We finally provide experimental support for our heuristically developed theory. [ABSTRACT FROM AUTHOR]

We consider a model (Lengyel-Epstein) reaction-diffusion system under spatial parametric modulation and demonstrate the effect of resonance shift of the Hopf-Turing boundary. A systematic perturbative and numerical analysis shows that this shift may induce spatial inhomogeneity on an homogeneous stable state resulting in pattern formation. [ABSTRACT FROM AUTHOR]

The ground state of the spiked harmonic oscillator with the potential V(r) = r[SUP2]+λ√r[SUPσ] has been obtained variationally for α < 3 and recently by a numerical procedure for α > 3. Due to the Klauder phenomemon at α = 3, analytic techniques do not smoothly interpolate between alpha; < 3 and α > 3. Here we use the N[SUP-1] expansion, where N is the dimensionality of space, to set up an analytic scheme that can be continued across α=3. [ABSTRACT FROM AUTHOR]

The article summarizes the support of genome sequencing projects in 2006 for modern evolutionary theory and contrasts these achievements with the deteriorating status of science education in the U.S. Like the human genome mega-project, sequencing the chimpanzee genome was a major scientific undertaking that involved the combined efforts of 67 scientists from 24 different research institutions using state-of-the art technology developed for the Human Genome Project. Phenomenal progress in genome science and DNA sequencing technology has enabled scientists to determine complete or partial genomic sequences of more than 1,000 species from diverse groups of organisms.

Work fluctuations and work probability distributions are fundamentally different in systems with short-ranged versus long-ranged correlations. Specifically, in systems with long-ranged correlations the work distribution is extraordinarily broad compared to systems with short-ranged correlations. This difference profoundly affects the possible applicability of fluctuation theorems like the Jarzynski fluctuation theorem. The Heisenberg ferromagnet, well below its Curie temperature, is a system with long-ranged correlations in very low magnetic fields due to the presence of Goldstone modes. As the magnetic field is increased the correlations gradually become short ranged. Hence, such a ferromagnet is an ideal system for elucidating the changes of the work probability distribution as one goes from a domain with long-ranged correlations to a domain with short-ranged correlations by tuning the magnetic field. A quantitative analysis of this crossover behavior of the work probability distribution and the associated fluctuations is presented. [ABSTRACT FROM AUTHOR]

The scattering of surface and internal waves by a single dike or a pair of identical dikes in a two-layer fluid is analyzed in two dimensions within the context of linearized theory of water waves. The dikes are approximated as cylinders of rectangular geometry and are placed in a two-layer fluid of finite depth. In the study, both the cases of surface-piercing and bottom-standing dikes are considered. The solution of the associated boundary value problem is derived by matched eigenfunction expansion method. Because of the flow discontinuity at the interface, the eigenfunctions involved have an integrable singularity at the interface and the orthonormal relation used in the present analysis is a generalization of the classical one corresponding to a single-layer fluid. The reflection coefficients and force amplitudes are computed and analyzed in various cases. The computed results in two-layer fluid are compared with those existing in the literature for a single-layer fluid. The results obtained by the matched eigenfunction expansion method are compared with that of wide spacing approximation method and it is observed that the results from both the methods are in good agreement when the dikes are widely spaced. The general behavior of reflection coefficients for interface-piercing and non-interface-piercing obstacles is found to be different in both the cases of surface-piercing and bottom-standing dikes. Moreover, for surface piercing dikes, the results show the possibility of a very large resonant motion between the dikes but with a very narrow bandwidth for the frequency of interest. [ABSTRACT FROM AUTHOR]

The scattering of surface and internal waves by a single dike or a pair of identical dikes in a two-layer fluid is analyzed in two dimensions within the context of linearized theory of water waves. The dikes are approximated as cylinders of rectangular geometry and are placed in a two-layer fluid of finite depth. In the study, both the cases of surface-piercing and bottom-standing dikes are considered. The solution of the associated boundary value problem is derived by a matched eigenfunction expansion method. Because of the flow discontinuity at the interface, the eigenfunctions involved have an integrable singularity at the interface and the orthonormal relation used in the present analysis is a generalization of the classical one corresponding to a single-layer fluid. The reflection coefficients and force amplitudes are comput ed and analyzed in various cases. The computed results in a two-layer fluid are compared with those existing in the literature for a single-layer fluid. The results obtained by the matched eigenfunction expansion method are compared with that of wide-spacing approximation method, and it is observed that the results from both the methods are in go od agreement when the dikes are widely spaced. The general behavior of reflection coefficients for interface-piercing and non-interface-piercing obstacles is found to be different in both cases of surface-piercing and bottom-standing dikes. Moreover, for surface-piercing dikes, the results show the possibility of very large resonant motions between the dikes but with a very narrow bandwidth for the frequency of interest. [ABSTRACT FROM AUTHOR]

We report a general formula for the critical electric field required to trigger a pattern formation in a Turing system in the presence of an electric field (drift term). Our result encompasses all situations from pure diffusion to pure drift. [ABSTRACT FROM AUTHOR]

Contents The successful outcome of an insemination is a combination of both male and female fertility-linked factors. We investigated the first service conception rate of cows at artificial insemination ( AI) in the smallholder dairy farms in Bangladesh. Frozen straws were prepared from ejaculates of Bos indicus (n = 7) and Bos indicus × Bos taurus (n = 7) AI bulls. Fertility was determined from 6101 first services in cows that were performed by 18 technicians in four regions between April 2004 and March 2005. Pregnancy was diagnosed by rectal palpation between 60 and 90 days post-insemination. The Asian version of Artificial Insemination Database Application ( AIDA ASIA) was used for bulls-, cows- and AI-related data recording, and later retrieved for analysis. The mean ± SD number of inseminations performed from individual bulls and their conception rates were 436.0 ± 21.6 and 50.7 ± 1.9%, respectively. Logistic regression demonstrated body condition scores ( BCS), heat detection signs, months of AI and their interactions had greatest effects (odds ratios: 1.24-16.65, p < 0.04-0.001) on first service conception rate in cows. Fertility differed (p < 0.02-0.001) between the regions, previous calving months, months of AI, BCS, parity and heat detection signs of cows. Inseminations based on mounting activity (n = 2352), genital discharge (n = 3263) and restlessness and/or other signs (n = 486) yielded a conception rate of 53.6%, 48.8% and 50.1%, respectively (p < 0.05). Conception rate between technicians ranged between 43.4% and 58.6% (p < 0.05). The days interval from calving to first service (overall mean ± SD = 153.4 ± 80.6) had relationship (p < 0.001) with BCS, months of previous calving and parity of the cows. Fertility at AI in smallholder farms can be improved by training farmers on nutrition and reproductive management of the cows. [ABSTRACT FROM AUTHOR]

We combine, within the Bohr Sommerfeld quantization rule, a systematic perturbation with asymptotic analysis of the action integral for potentials which support a finite number of bound states with E < 0 to obtain an interpolation formula for the energy eigenvalues. We find interpolation formulae for the Morse potential as well as potentials of the form $${V=V_0 \left[ {\left( {\frac{a}{x}} \right)^{2k}-\left( {\frac{a}{x}}\right)^{k}} \right]}$$. For k = 6 i.e. the well known Lennard Jones potential this yields results within 1 per cent of the highly accurate numerical values. For the Morse potential this procedure yields the exact answer. We find that the result for the Morse potential which approaches zero exponentially is the $${k\rightarrow\infty}$$ limit of the Lennard Jones class of potentials. [ABSTRACT FROM AUTHOR]

We use the renormalization group to set up an easy algorithm for finding the amplitude equation for an arbitrary two dimensional dynamical system of the Liénard type. This allows us to address the second part of Hilbert's sixteenth problem, at least in the weak damping limit. [ABSTRACT FROM AUTHOR]

We consider a gas of bosonic atoms near a Feshbach resonance. The dynamics of the atomic and molecular condensates can be described in the limit of small fluctuations by a set of coupled nonlinear Gross Piteaviskii equations. In the case of a strong atom-molecule conversion, the system has an integral motion for the spatially uniform solutions which exhibits temporal oscillation. The possible consequence of this oscillation may be the existence of Josephson like current in the condensates which has been investigated. [ABSTRACT FROM AUTHOR]

Abstract: Synthesis of ternary Ti0.9Ni0.1C carbide by high energy ball-milling of the stoichiometric elemental powder mixture under argon atmosphere is investigated in detail. Microstructure characterization of ball-milled samples in terms of lattice imperfections and quantitative estimation of different phases present in the samples have been made by analyzing the X-ray diffraction data employing Rietveld''s powder structure refinement method. The results reveal that the formation of Ti0.9Ni0.1C nano-carbide starts after 55min of ball-milling from Ti–Ni–C solid solution. After 8h of milling full formation of Ti0.9Ni0.1C is achieved without any contaminated phase. To study the effect of milling time on particle size, ball-milling is continued up to 12h and the results indicate that particle size reaches its lowest value after 8h of milling and then starts to agglomerate. Direct observation of microstructure of 12h ball-milled sample under high resolution TEM reveals supportive evidence of structural and microstructural evolution by indirect method using XRD data. [Copyright &y& Elsevier]

Abstract Background and Aims: Coagulation disorders commonly develop in patients with cirrhosis of the liver. They have also been reported in patients with non-cirrhotic portal fibrosis (NCPF) and extra-hepatic portal venous obstruction (EHPVO); the two conditions with portal hypertension and near-normal liver functions. The spectrum and prevalence of coagulation abnormalities and their association with the pathogenesis of these diseases and with hypersplenism was prospectively studied. Methods: Eighteen EHPVO patients that included an equal number of NCPF patients and 20 healthy controls were prospectively studied. The coagulation parameters assessed included: international normalized ratio, partial thromboplastin time, and fibrinogen and fibrinogen degradation products. Platelet aggregation and malondialdehyde levels were measured. Results: Both EHPVO (83%) and NCPF (78%) patients had a significantly prolonged international normalized ratio and a decrease in fibrinogen and platelet aggregation. The EHPVO patients had a significant prolongation in partial thromboplastin time (67% patients), with increased levels of fibrinogen degradation product levels occurring in all patients; these were normal in NCPF patients. Platelet malondialdehyde levels were normal in both groups. Hypersplenism was present in four EHPVO and seven NCPF patients. It did not significantly influence the coagulation profile in either NCPF or EHPVO patients. Conclusions: Coagulation anomalies are common and significant in both NCPF and EHPVO patients, suggestive of a mild disseminated intravascular coagulation disorder. These imbalances could be caused by chronic subclinical endotoxemia and cytokine activation after the initial portal thromboembolic event. The persistence of these abnormalities in adolescent patients indicates an ongoing coagulation derangement. [ABSTRACT FROM AUTHOR]

Between 100 kHz and 2 GHz ultrasonic attenuation spectra of two aqueous solutions of vesicles from 1,2-dimyristoyl-L-3-phosphatidylcholine have been measured at 13 temperatures around the main phase transition temperature of the membranes. The spectra are analyzed in terms of an asymptotic high frequency background contribution and three relaxation terms. Two of these terms can be represented by a discrete relaxation time, respectively, the other one extends over a significantly broader frequency range than a Debye-type relaxation term. It was found to nicely follow the predictions of the Bhattacharjee-Ferrell model of three-dimensional critical fluctuations. This finding has been additionally verified by measurements of the scaling function and by an analysis of the relaxation rate of order parameter fluctuations following from the fit of the experimental scaling function data to the theoretical form. Theoretical arguments are presented to indicate why the three-dimensional theory applies so well to the quasi-two-dimensional membrane system. [ABSTRACT FROM AUTHOR]

Background Reproductive disorders have been found to be a major reason for decreased reproductive efficiency in animals. The present study was conducted to determine the effectiveness of different treatment for various reproductive diseases of domestic animals in Veterinary Teaching Hospital (VTH), Bangladesh Agricultural University (BAU), Mymensingh. Methods A total of 100 animals were registered for treatment during the study period. Among those 59 cattle, 9 goats and 1 turkey were treated for reproduction related diseases. On the other hand, 28 cows and 3 goats were brought for regular pregnancy diagnosis. Standard procedures were followed for the diagnosis and treatment of the diseases. Results Among the reproductive diseases of cattle, conception failure was 37.29% (n=22), uterine infection was 33.89% (n=20), anestrous was 13.56% (n=8), repeat breeding was 5.08% (n=3), vaginal prolapse was 3.39% (n=2), pastular vulvo-vaginitis was 1.69% (n=1) and ovarian hypoplasia was 1.69% (n=1). Only 2 bulls 3.39% (n=2) were diagnosed with posthitis. In goats, retention of placenta was 66.67% (n=6), abortion was 22.22% (n=2) and anestrous was 11.11% (n=1). There was one turkey with cloacal prolapse. All the animals having reproductive disease were treated in VTH. There was 93.22% improvement/effectiveness found in cows. The turkey and goats show 100% effectiveness of treatment. Conclusion We can conclude that the most common reproductive diseases of cattle and goats in Bangladesh are uterine infection, anestrous, conception failure, pastular vulvo-vaginitis, vaginal prolapse, repeat breeding syndrome, abortion, retention of placenta and posthitis. Any disease or disorder of the genital tract may affect the reproduction as well as the production and fertility. Therefore, it is important to be concerned about the treatment and management of the diseases of the genital tract. Careful management and treatment of these diseases will ultimately help to increase the animal's productivity in Bangladesh. The treatment given in VTH, BAU are successful for recovery. [ABSTRACT FROM AUTHOR]

Background Repeat breeding syndrome (RBS), an important reproductive disorder of dairy cattle, results in high economic losses in the dairy industry. The study was conducted to determine the factors of repeat breeding in crossbred dairy cows at selected areas of Bangladesh. Methods A total of 592 breedable cows from 34 farms were examined from Mymensingh and Chittagong district. Seventy cows were identified as repeat breeder cows and another 23 cows were randomly selected as healthy control cows for the study. Results The number of calving, the interval between first post-partum heat and last service date, number of services failed and consecutive services failed, the number of medications given, and number of suckling were found significantly higher in repeat breeder cows compared to normal healthy cows. Body weight and Body condition score (BCS) were significantly lower in repeat breeder cows compared to normal healthy cows. There were no significant differences in the estrus cycle length and concentrate feeding in both repeat breeder and healthy cows. The lowest occurrence of repeat breeder was recorded in cows fed with a larger amount of green grass. Remarkably, the highest occurrence of repeat breeder was recorded in cows fed with a significant amount of straw. Conclusion The identified features of repeat breeding syndrome will help in disseminating awareness on factors affecting the occurrence of repeat breeding syndrome in crossbred cows. [ABSTRACT FROM AUTHOR]