The electron-phonon coupling is large for localized states

From density functional calculations, we show that localized states stemming from defects or topological disorder exhibit an anomalously large electron-phonon coupling. We provide a simple analysis to explain the observation and perform a detailed study on an interesting system: amorphous silicon. We compute first principles deformation potentials (by computing the sensitivity of specific electronic eigenstates to individual classical normal modes of vibration). We also probe thermal fluctuations in electronic eigenvalues by first principles thermal simulation. We find a strong correlation between a static property of the network [localization, as gauged by inverse participation ratio (IPR)] and a dynamical property (the amplitude of thermal fluctuations of electron energy eigenvalues) for localized electron states. In particular, both the electron-phonon coupling and the variance of energy eigenvalues are proportional to the IPR of the localized state. We compare the results for amorphous Si to photoemission experiments. While the computations are carried out for silicon, very similar effects have been seen in other systems with disorder.Comment: 5 pages, 3 PostScript figure

Three dimensional steady and unsteady asymmetric flow past wings of arbitrary planforms

The nonlinear discrete vortex method was extended to treat the problem of asymmetric flows past a wing with leading-edge separation, including steady and unsteady flows. The problem was formulated in terms of a body-fixed frame of reference, and the nonlinear discrete vortex method was modified accordingly. Only examples of flows past delta wings are presented. Comparison of these results with experimental results for a delta wing undergoing a steady rolling motion at zero angle of attack demonstrates the superiority of the present method in obtaining highly accurate loads. Numerical results for yawed wings at large angles of attack are also presented. In all cases, total load coefficients, pressure distributions and shapes of the free-vortex sheets are shown

Advancing Communities of Learning: A Collaborative Project between Local Universities, Funding Agencies, and Nonprofits to Develop a Subsidized Senior-Transportation Plan

The growing population of seniors in the United States poses both interesting and challenging transportation policy issues that demand research on alternatives to current transportation systems. This study was motivated by a local foundation’s interest in senior quality-of-life issues in the communities served. The aim of this study was to assess senior transportation needs and systems as a means to move policy makers and funders closer to providing high-quality senior transportation services. The localized nature of senior transportation needs is best examined as a case study. In this article, one mid-sized Indiana community is examined using focus group interviews and individual surveys of senior citizens. In addition, a survey of the literature on senior-transportation models provided critical information relevant to formulating best-practice recommendations for community-level senior-transportation systems. To design effective senior-transportation systems, five critical factors are evaluated. Finally, the article presents a case study highlighting the importance of multisector collaboration in addressing the challenges and opportunities associated with critical senior-transportation issues in upcoming decades

How to Solve the Fronthaul Traffic Congestion Problem in H-CRAN?

The design of efficient wireless fronthaul connections for future heterogeneous networks incorporating emerging paradigms such as heterogeneous cloud radio access network (H-CRAN) has become a challenging task that requires the most effective utilization of fronthaul network resources. In this paper, we propose and analyze possible solutions to facilitate the fronthaul traffic congestion in the scenario of Coordinated Multi-Point (CoMP) for 5G cellular traffic which is expected to reach ZetaByte by 2017. In particular, we propose to use distributed compression to reduce the fronthaul traffic for H-CRAN. Unlike the conventional approach where each coordinating point quantizes and forwards its own observation to the processing centre, these observations are compressed before forwarding. At the processing centre, the decompression of the observations and the decoding of the user messages are conducted in a joint manner. Our results reveal that, in both dense and ultra-dense urban small cell deployment scenarios, the usage of distributed compression can efficiently reduce the required fronthaul rate by more than 50% via joint operation

Polyunsaturated fatty acids influence offspring sex ratio in cows

Dietary polyunsaturated fatty acids (PUFAs) can influence fertility in farm animals. Some evidence in mice and sheep have suggested that PUFAs may influence offspring sex ratio, which may have significant value for cattle production. To test this hypothesis, three groups of Holstein cows were supplemented with either 0%, 3% or 5% protected fat (PF) in the form of calcium salt of fatty acids (rich in omega-6) from 14–21 days pre-partum until conception. Proven-fertile frozen semen from the same ejaculate was used for insemination. Calf sex recorded at birth was 8/19 (42.1%) male offspring in the control group, increasing to 14/20 (70%, P > 0.05) and 17/20 (85%, P < 0.05) in 3% and 5% PF, respectively. To test if this effect was caused by a direct influence on the oocyte, we supplemented bovine cumulus oocyte complexes during in vitro maturation with either omega-3 alpha-linolenic acid (ALA), omega-6 linoleic acid (LA) or trans-10, cis-12 conjugated linoleic acid (CLA). Sex ratio of the produced transferable embryos was determined using PCR of SRY gene. Similar to the in vivo results, sex ratio was skewed to the male side in the embryos derived from LA- and CLA-treated oocytes (79% and 71%) compared to control and ALA-treated oocytes (44% and 54%, respectively). These results indicate that both dietary and in vitro supplementation of omega-6 PUFAs can skew the sex ratio towards the male side in cattle. Further experiments are required to confirm this effect on a larger scale and to study the mechanisms of action that might be involved

Unsteady flow past wings having sharp-edge separation

A vortex-lattice technique is developed to model unsteady, incompressible flow past thin wings. This technique predicts the shape of the wake as a function of time; thus, it is not restricted by planform, aspect ratio, or angle of attack as long as vortex bursting does not occur and the flow does not separate from the wing surface. Moreover, the technique can be applied to wings of arbitrary curvature undergoing general motion; thus, it can treat rigid-body motion, arbitrary wing deformation, gusts in the freestream, and periodic motions. Numerical results are presented for low-aspect rectangular wings undergoing a constant-rate, rigid-body rotation about the trailing edge. The results for the unsteady motion are compared with those predicted by assuming quasi-steady motion. The present results exhibit hysteretic behavior

Experimentally Constrained Molecular Relaxation: The case of hydrogenated amorphous silicon

We have extended our experimentally constrained molecular relaxation technique (P. Biswas {\it et al}, Phys. Rev. B {\bf 71} 54204 (2005)) to hydrogenated amorphous silicon: a 540-atom model with 7.4 % hydrogen and a 611-atom model with 22 % hydrogen were constructed. Starting from a random configuration, using physically relevant constraints, {\it ab initio} interactions and the experimental static structure factor, we construct realistic models of hydrogenated amorphous silicon. Our models confirm the presence of a high frequency localized band in the vibrational density of states due to Si-H vibration that has been observed in a recent vibrational transient grating measurements on plasma enhanced chemical vapor deposited films of hydrogenated amorphous silicon.Comment: 13 pages, 4 figure

Influence of gas flow rate on liquid distribution in trickle-beds using perforated plates as liquid distributors

Two wire mesh tomography devices and a liquid collector were used to study the influence of the gas flow rate on liquid distribution when fluids distribution on top of the reactor is ensured by a perforated plate. In opposition to most of the studies realized by other authors, conditions in which the gas has a negative impact in liquid distribution were evidenced. Indeed, the obtained results show that the influence of gas flow rate depends on the quality of the initial distribution, as the gas forces the liquid to "respect" the distribution imposed at the top of the reactor. Finally, a comparison between the two measuring techniques shows the limitations of the liquid collector and the improper conclusions to which its use could lead

Perancangan Sistem Informasi Manajemen Produksi Dengan Pemanfaatan Pendekatan Fuzzy Logic Untuk Penentuan Jumlah Produksi

Ketidak pastian permintaan produk menjadikan kebutuhan informasi yang cepat dan tepat menjadi syarat mutlak yang tersedia secara up to date sebagai pertimbangan dalam pengambilan keputusan jumlah produksi. Saat ini, pengelolaan permintaan produk keripik singkong di UD Lumba-lumba masih dilakukan secara manual. Pencatatan yang dilakukan secara manual dirasa kurang efisien, sebab dibutuhkan ketelitian dan kedisiplinan pegawai dalam melakukan update informasi. Selain itu, dalam pengambilan keputusan jumlah produksi di UD Lumba-lumba juga masih menggunakan keputusan subyektif dari penanggung jawab produksi. Oleh karena itu, perlu adanya perancangan sistem informasi manajemen produksi dengan pemanfaatan sistem database sebagai pengelola data serta penerapan pendekatan fuzzy logic untuk membantu dalam pengambilan keputusan jumlah produksi. Sistem informasi manajemen produksi dirancang untuk mengotomasi sistem yang telah ada di UD Lumba-lumba agar lebih baik. Perancangan prototype sistem informasi manajemen produksi, dilakukan dengan membangun aplikasi berbasis web menggunakan bahasa pemrograman PHP dan database MySQL. Berdasarkan uji prototype yang dilakukan, sistem informasi manajemen produksi mampu memberikan informasi-informasi yang berkaitan dengan permintaan produk, persediaan dan memberikan rekomendasi terhadap jumlah produksi. Dengan pemanfaatan sistem informasi dan database, pengelolaan data serta penyediaan informasi menjadi lebih baik, cepat dan efisien