Exact solution for the energy density inside a one-dimensional non-static cavity with an arbitrary initial field state

We study the exact solution for the energy density of a real massless scalar field in a two-dimensional spacetime, inside a non-static cavity with an arbitrary initial field state, taking into account the Neumann and Dirichlet boundary conditions. This work generalizes the exact solution proposed by Cole and Schieve in the context of the Dirichlet boundary condition and vacuum as the initial state. We investigate diagonal states, examining the vacuum and thermal field as particular cases. We also study non-diagonal initial field states, taking as examples the coherent and Schrodinger cat states.Comment: 10 pages, 8 figure

Process transparency on construction sites : examples from construction companies in Brazil

Process transparency is the core concept in Visual Management (VM), which is one of the founding blocks of the Toyota Production System. This paper presents the preliminary results of a collaborative research conducted between Brazil and the UK, as part of a research effort focused on the application of Visual Management in construction. How process transparency is realized on construction sites is the main research question of the paper. The use of this concept and the implementation of the transparency theory were investigated through multiple case studies, carried out in nine different construction companies. The findings are explained through six theoretical transparency increasing approaches. The affecting parameters in the application of, the management’s perception of and several methods in process transparency in construction were identified. Further work, especially exploring the functions of process transparency on construction sites and reflecting the worker perception of the issue, is necessary to elaborate the process transparency concept

Trapoeraba: problema para a produção e comercialização de semente de capim.

bitstream/item/37329/1/Comunicado48.pd

Post-AGB Stars in Globular Clusters and Galactic Halos

We discuss three aspects of post-AGB (PAGB) stars in old populations. (1) HST photometry of the nucleus of the planetary nebula (PN) K 648 in the globular cluster (GC) M15 implies a mass of 0.60 Msun, in contrast to the mean masses of white dwarfs in GCs of ~0.5 Msun. This suggests that K 648 is descended from a merged binary, and we infer that single Pop II stars do not produce visible PNe. (2) Yellow PAGB stars are the visually brightest stars in old populations (Mv ~ -3.3) and are easily recognizable because of their large Balmer jumps; thus they show great promise as a Pop II standard candle. Two yellow PAGB stars in the GC NGC 5986 have the same V magnitudes to within +/-0.05 mag, supporting an expected narrow luminosity function. (3) Using CCD photometry and a u filter lying below the Balmer jump, we have detected yellow PAGB stars in the halo of M31 and in its dwarf elliptical companion NGC 205. With the Milky Way zero point, we reproduce the Cepheid distance to M31, and find that NGC 205 is ~100 kpc further away than M31. The star counts imply a yellow PAGB lifetime of about 25,000 yr, and their luminosities imply masses near 0.53 Msun.Comment: 6 pages, 2 figures. To appear in proceedings of Torun, Poland, workshop on "Post-AGB Objects (Proto-Planetary Nebulae) as a Phase of Stellar Evolution," ed. S.K. Gorn

Amplitude analysis of four-body decays using a massively-parallel fitting framework

The GooFit Framework is designed to perform maximum-likelihood fits for arbitrary functions on various parallel back ends, for example a GPU. We present an extension to GooFit which adds the functionality to perform time-dependent amplitude analyses of pseudoscalar mesons decaying into four pseudoscalar final states. Benchmarks of this functionality show a significant performance increase when utilizing a GPU compared to a CPU. Furthermore, this extension is employed to study the sensitivity on the $D^0 - \bar{D}^0$ mixing parameters $x$ and $y$ in a time-dependent amplitude analysis of the decay $D^0 \rightarrow K^+\pi^-\pi^+\pi^-$. Studying a sample of 50 000 events and setting the central values to the world average of $x = (0.49 \pm0.15) \%$ and $y = (0.61 \pm0.08) \%$, the statistical sensitivities of $x$ and $y$ are determined to be $\sigma(x) = 0.019 \%$ and $\sigma(y) = 0.019 \%$.Comment: Proceedings of the 22nd International Conference on Computing in High Energy and Nuclear Physics, CHEP 201

Short-reach MCF-based systems employing KK Receivers and feedforward neural networks for ICXT mitigation

This paper proposes and evaluates the use of machine learning (ML) techniques for mitigating the effect of the random inter-core crosstalk (ICXT) on 256 Gb/s short-reach systems employing weakly coupled multicore fiber (MCF) and Kramers–Kronig (KK) receivers. The performance improvement provided by the k-means clustering, k nearest neighbor (KNN) and feedforward neural network (FNN) techniques are assessed and compared with the system performance obtained without employing ML. The FNN proves to significantly improve the system performance by mitigating the impact of the ICXT on the received signal. This is achieved by employing only 10 neurons in the hidden layer and four input features for the training phase. It has been shown that k-means or KNN techniques do not provide performance improvement compared to the system without using ML. These conclusions are valid for direct detection MCF-based short-reach systems with the product between the skew (relative time delay between cores) and the symbol rate much lower than one (skew×symbol rate≪1). By employing the proposed FNN, the bit error rate (BER) always stood below 10−1.8 on all the time fractions under analysis (compared with 100 out of 626 occurrences above the BER threshold when ML was not used). For the BER threshold of 10−1.8 and compared with the standard system operating without employing ML techniques, the system operating with the proposed FNN shows a received optical power improvement of almost 3 dB.info:eu-repo/semantics/publishedVersio