Pseudogap and incommensurate magnetic fluctuations in YBa_2Cu_3O_{6. 6}

Unpolarized inelastic neutron scattering is used to study the temperature and wave vector dependence of the dynamical magnetic susceptibility, $\chi''(q,\omega)$, of a well characterized single crystal $YBa_2Cu_3O_{6.6}$ ($T_c=62.7$ K). We find that a pseudogap opens in the spin fluctuation spectrum at temperatures well above $T_c$. We speculate that the appearance of the low frequency incommensurate fluctuations is associated with the opening of the pseudogap. To within the error of the measurements, a gap in the spin fluctuation spectrum is found in the superconducting state.Comment: 6 pages, 3 ps figs, Proceedings of ICNS, Physica B, to be publishe

Dynamics of quantum adiabatic evolution algorithm for Number Partitioning

We have developed a general technique to study the dynamics of the quantum adiabatic evolution algorithm applied to random combinatorial optimization problems in the asymptotic limit of large problem size $n$. We use as an example the NP-complete Number Partitioning problem and map the algorithm dynamics to that of an auxilary quantum spin glass system with the slowly varying Hamiltonian. We use a Green function method to obtain the adiabatic eigenstates and the minimum excitation gap, $g_{\rm min}={\cal O}(n 2^{-n/2})$, corresponding to the exponential complexity of the algorithm for Number Partitioning. The key element of the analysis is the conditional energy distribution computed for the set of all spin configurations generated from a given (ancestor) configuration by simulteneous fipping of a fixed number of spins. For the problem in question this distribution is shown to depend on the ancestor spin configuration only via a certain parameter related to the energy of the configuration. As the result, the algorithm dynamics can be described in terms of one-dimenssional quantum diffusion in the energy space. This effect provides a general limitation on the power of a quantum adiabatic computation in random optimization problems. Analytical results are in agreement with the numerical simulation of the algorithm.Comment: 32 pages, 5 figures, 3 Appendices; List of additions compare to v.3: (i) numerical solution of the stationary Schroedinger equation for the adiabatic eigenstates and eigenvalues; (ii) connection between the scaling law of the minimum gap with the problem size and the shape of the coarse-grained distribution of the adiabatic eigenvalues at the avoided-crossing poin

Macro- and micro-strain in GaN nanowires on Si(111)

We analyze the strain state of GaN nanowire ensembles by x-ray diffraction. The nanowires are grown by molecular beam epitaxy on a Si(111) substrate in a self-organized manner. On a macroscopic scale, the nanowires are found to be free of strain. However, coalescence of the nanowires results in micro-strain with a magnitude from +-0.015% to +-0.03%.This micro-strain contributes to the linewidth observed in low-temperature photoluminescence spectra

Error resilient video transcoding for robust inter-network communications using GPRS

A novel fully comprehensive mobile video communications system is proposed in this paper. This system exploits the useful rate management features of the video transcoders and combines them with error resilience for transmissions of coded video streams over general packet radio service (GPRS) mobileaccess networks. The error-resilient video transcoding operation takes place at a centralized point, referred to as a video proxy, which provides the necessary output transmission rates with the required amount of robustness. With the use of this proposed algorithm, error resilience can be added to an already compressed video stream at an intermediate stage at the edge of two or more different networks through two resilience schemes, namely the adaptive intra refresh (AIR) and feedback control signaling (FCS) methods. Both resilience tools impose an output rate increase which can also be prevented with the proposed novel technique in this paper. Thus, an error-resilient video transcoding scheme is presented to give robust video outputs at near target transmission rates that only require the same number of GPRS timeslots as the nonresilient schemes. Moreover, an ultimate robustness is also accomplished with the combination of the two resilience algorithms at the video proxy. Extensive computer simulations demonstrate the effectiveness of the proposed system

Full Length Research Paper Improving the traditional sesame seed planting with seed pelleting

The aim of this study is to determine the effect of seed pelleting in a variety of sesame types on yield and yield factors. In this study, it is suggested that with the help of seed pelleting, it will be possible toachieve a better planting, and subsequently, to acquire an increase in the yield and its elements. In this research, Muganli-57, Ozberk-82 and Golmarmara type seeds were used, which are all officially registered and commonly used seed kinds in Turkey. Two types of planting were utilized: 1- the traditional planting method used worldwide, 2- alternative sensitive method. In the sensitive method, the pelleted sesame seeds treated with a special pelleting mixture had a diameter of 3 mm or larger.These pelleted sesame seeds were planted with a pneumatic spacing planter. This study was done in Adnan Menderes University, Agricultural Faculty, Research and Practice Centers located in MenderesPlain and in the field of the plant production center of Dalaman. The arable field trials were done in two locations with a split plot trial method with three replications. In this study, the height of the plants(cm), number of lateral branches (lateral branches plant-1), number of capsules per plant (capsule plant-1), height of first capsule (cm), number of plants harvested per square meter, yield (kg ha-1) and thousand kernel weight (g) were analyzed for both pelleted and nonpelleted sesame seeds. As a result, the pelleted sesame seeds improved the yield significantly compared to the normal sesame seeds. It was found that the pelleted sesame seeds had a mean yield value of 1976.3 kg ha-1, whereas the nonpelleted sesame seeds had a mean yield value of 1243.2 kg ha-1. Statistically significant differences exist between the pelleted and non-pelleted seeds in terms of the height of the plants (cm), number oflateral branches per plant (branch plant-1), number of capsules per plant (capsule plant-1), height of first capsule (cm), number of plants harvested (plant/ m2), yield values (kg ha-1) and thousand kernel weight (g)

Preparation and characterization of photochromic effect for ceramic tiles

Ceramic tile industry is developing due to the technological researches in scientific area and new tiles which are not only a traditional ceramic also have many multiple functionalities have been marketed nowadays. These tiles like photocatalytic, photovoltaic, antibacterial and etc. improve the quality of life and provide lots of benefits such as self cleaning, energy production, climate control. The goal of this study was to enhance the photochromic function on ceramic tiles which is the attitude of changing color in a reversible way by electromagnetic radiation and widely used in many areas because of its aesthetic and also functional properties. High response time of photochromic features of ceramic tiles have been achieved by employing of polymeric gel with additives of photoactive dye onto the ceramic surface. Photochromic layer with a thickness of approximately 45- 50 μm was performed by using spray coating technique which provided homogeneous deposition on surface. Photochromic ceramic tiles with high photochromic activity such as reversibly color change between ΔE= 0.29 and 26.31 were obtained successfully. The photochromic performance properties and coloring-bleaching mechanisms were analyzed by spectrophotometer. The microstructures of coatings were investigated both by stereo microscopy and scanning electron microscopy (SEM).Peer reviewe

Banking Geography and Cross-Fertilization in the Productivity Growth of US Commercial Banks

The US banking industry offers a unique, natural and fertile environment to study geography's effects on banks' behavior and performance. The literature on banks' operating performance, while extensive, says little about the influence of spatial interactions on banks' performance. We compute and examine, using a physical distance-based spatio-temporal empirical model, the state-wide total factor productivity growth (TFPG) indices of US commercial banks for each state for the 1971-1995 period. We observe that the productivity growth of commercial banks in state i depends strongly, positively, and contemporaneously on the productivity growth of commercial banks located in state i's contiguous states. Further, “regulatory space” appears to induce frictions and lessen the documented spatial interactions. These findings support our plea that research on commercial banking sector's behavior need to pay a particular attention to the effects of banking geography.Spatial, Commercial Banks, Total Factor Productivity Growth, Kalman Filter