Photonic Crystal Laser Accelerator Structures

Photonic crystals have great potential for use as laser-driven accelerator structures. A photonic crystal is a dielectric structure arranged in a periodic geometry. Like a crystalline solid with its electronic band structure, the modes of a photonic crystal lie in a set of allowed photonic bands. Similarly, it is possible for a photonic crystal to exhibit one or more photonic band gaps, with frequencies in the gap unable to propagate in the crystal. Thus photonic crystals can confine an optical mode in an all-dielectric structure, eliminating the need for metals and their characteristic losses at optical frequencies. We discuss several geometries of photonic crystal accelerator structures. Photonic crystal fibers (PCFs) are optical fibers which can confine a speed-of-light optical mode in vacuum. Planar structures, both two- and three-dimensional, can also confine such a mode, and have the additional advantage that they can be manufactured using common microfabrication techniques such as those used for integrated circuits. This allows for a variety of possible materials, so that dielectrics with desirable optical and radiation-hardness properties can be chosen. We discuss examples of simulated photonic crystal structures to demonstrate the scaling laws and trade-offs involved, and touch on potential fabrication processes.Comment: 3 pages, 3 figures; Submitted to Particale Accelerator Conference (PAC 2003), May 12-16, 2003, Portland, Oregon (IEEE

Sharp entanglement thresholds in the logarithmic negativity of disjoint blocks in the transverse-field Ising chain

Entanglement has developed into an essential concept for the characterization of phases and phase transitions in ground states of quantum many-body systems. In this work, we use the logarithmic negativity to study the spatial entanglement structure in the transverse-field Ising chain both in the ground state and at nonzero temperatures. Specifically, we investigate the entanglement between two disjoint blocks as a function of their separation, which can be viewed as the entanglement analog of a spatial correlation function. We find sharp entanglement thresholds at a critical distance beyond which the logarithmic negativity vanishes exactly and thus the two blocks become unentangled, which holds even in the presence of long-ranged quantum correlations, i.e., at the system's quantum critical point. Using Time-Evolving Block Decimation (TEBD), we explore this feature as a function of temperature and size of the two blocks and present a simple model to describe our numerical observations.Comment: 12 pages, 7 figure

Association between GH encoding gene polymorphism and semen characteristics in Iranian Holstein bulls

The objective of this present study was to investigate relationships between the growth hormone gene restriction fragment length  polymorphism (RFLP) and bull sperm characteristics. A total of 89 bullsfrom two semen evaluation stations were genotyped for the bovine growth hormone (bGH)-AluI polymorphism by polymerase chain reaction and followed by 4% metaphor agaros gel electrophoresis. The overall allele frequencies for two L and V alleles were 0.50, respectively. The relationship between the bGH-AluI polymorphism and semen characteristics was evaluated according 1500 ejaculated records. Five sperm characteristics were analyzed. Sperm characteristics showed significant variabilityin relation to bGH genotypes. LL bulls had a lower ejaculated volume and higher percentage of live sperm, and VV bulls had higher fresh sperm concentration and minimum effect after cryopreservation. This polymorphism could be further used for semen evaluation process in artificial insemination program in Iranian Holstein bulls.Key word: Semen characteristics, growth hormone (GH) polymorphism, Holstein bulls

Comparing high-resolution gridded precipitation data with satellite rainfall estimates of TRMM_3B42 over Iran

To evaluate satellite rainfall estimates of Tropical Rain Measurement Mission (TRMM) level 3 output (3B42) (TRMM_3B42) over Iran (20°–45° N, 40°–65° E), we compared these data with high-resolution gridded precipitation datasets (0.25°×0.25° latitude/longitude) based on rain gauges (Iran Synoptic gauges Version 0902 (IS0902)). Spatial distribution of mean annual and mean seasonal rainfall in both IS0902 and TRMM_3B42 from 1998 to 2006 shows two main rainfall patterns along the Caspian Sea and over the Zagros Mountains. Scatter plots of annual average rainfall from IS0902 versus TRMM_3B42 for each 0.25°×0.25° grid cell over the entire country (25°–40° N, 45°–60° E), along the Caspian Sea (35°–40° N, 48°–56° E), and over the Zagros Mountains (28°–37° N, 46°–55° E) were derived. For the entire country, the Caspian Sea region, and the Zagros Mountains, TRMM_3B42 underestimates mean annual precipitation by 0.17, 0.39, and 0.15 mm day^−1, respectively, and the mean annual rainfall spatial correlation coefficients are 0.77, 0.57, and 0.75, respectively. The mean annual precipitation temporal correlation coefficient for IS0902 and TRMM_3B42 is ~0.8 in the area along the Zagros Mountains, and ~0.6 in the Caspian Sea and desert regions

Vermicompost Application in Different Intercropping Patterns Improves the Mineral Nutrient Uptake and Essential Oil Compositions of Sweet Basil (Ocimum basilicum L.)

Only a few studies have hitherto investigated the effects of the application of organic fertilizers in intercropping systems on the plant essential oil (EO) productivity. Hence, this work has aimed to study the effect of different intercropping patterns on EO quality and quantity of sweet basil (Ocimum basilicum L.) under vermicompost application. In the present study, the cropping patterns consisted of 1B:1CB, 2B:2CB, 3B:2CB, and 4B:2CB (basil: common bean) as well as the pure culture of both crops and fertilizer treatments including usage or non-usage of vermicompost. The maximum seed yield of common bean (2786 kg ha−1) and dry matter yield of basil in the first (261.5 g m−2) and second harvests (214.7 g m−2) were recorded in the pure cultures fertilized with vermicompost. In addition, the nutrient uptake rate of macronutrients and micronutrients in both plants after application of vermicompost improved in intercropping patterns. In both harvests, the maximum EO content of basil (0.84% in the first harvest and 0.69% in the second harvest) was observed at the cropping ratio of 3B:2CB fertilized with vermicompost. Chemical analysis, achieved by GC–MS, evidenced 1,8-cineole, linalool, methyl chavicol, α-trans-bergamotene, methyl eugenol, and epi-α-cadinol as the main basil EO constituents in both harvests. The highest increment level for most ofEO constituents, nutrient uptake, and land equivalent ratio (1.52) were obtained in the intercropping pattern of 3B:2CB fertilized with vermicompost. In general, the intercropping pattern of 3B:2CB after use of vermicompost can improve the EO productivity and quality of basil. This intercropping pattern was accompanied by the increment of nutrient uptake. Therefore, this treatment can be introduced as a valid and sustainable strategy to replace chemical fertilizer and plant monoculture

Probabilistic Reconstruction in Compressed Sensing: Algorithms, Phase Diagrams, and Threshold Achieving Matrices

Compressed sensing is a signal processing method that acquires data directly in a compressed form. This allows one to make less measurements than what was considered necessary to record a signal, enabling faster or more precise measurement protocols in a wide range of applications. Using an interdisciplinary approach, we have recently proposed in [arXiv:1109.4424] a strategy that allows compressed sensing to be performed at acquisition rates approaching to the theoretical optimal limits. In this paper, we give a more thorough presentation of our approach, and introduce many new results. We present the probabilistic approach to reconstruction and discuss its optimality and robustness. We detail the derivation of the message passing algorithm for reconstruction and expectation max- imization learning of signal-model parameters. We further develop the asymptotic analysis of the corresponding phase diagrams with and without measurement noise, for different distribution of signals, and discuss the best possible reconstruction performances regardless of the algorithm. We also present new efficient seeding matrices, test them on synthetic data and analyze their performance asymptotically.Comment: 42 pages, 37 figures, 3 appendixe

Legacy of COVID‐19 – the opportunity to enhance surgical services for patients with colorectal disease

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