A summary of the XAFS X Conference in Chicago

International Nuclear Information System (INIS)

Kemner, K.; Sayers, D.

1999-01-01

On August 10-14, 1998, the 10th International Conference on X-ray Absorption Fine Structure (XAFS X) was held on the Illinois Institute of Technology campus in Chicago. This is one of the major synchrotron radiation conferences, held every two years since 1981 when the first international meeting of XAFS experts was held in Daresbury, coincident with the operation of the first of the second-generation dedicated synchrotron radiation sources. The XAFS conferences have evolved over the years with the more recent conferences covering not only the advances in instrumentation, theory and method but also their applications in disciplines ranging from biological to environmental sciences. Approximately 360 scientists from 23 countries attended the conference. The program consisted of 467 abstracts for plenary talks, invited talks, contributed talks, and posters. The co-chairs for the conference were B. Bunker, S. Heald, and T. Morrison and the Program Chair was J. Penner-Hahn. The first IXS award for career contributions to the field was presented to F. Lytle who gave a plenary talk on 'The EXAFS Family Tree: History of the Development of X-ray Absorption Spectroscopy'. In addition, awards were given for the best poster by a young scientist at each session. The winners were M. Duff, D. Cabaret and S. Rossano. The International Union of Crystallography (IUCr) also sponsored poster prizes for the best posters in the areas of biology and instrumentation and methods. These winners were A. Templeton and M. Suzuki

Using XAFS, EDAX and AFM in comparative study of various natural and synthetic emeralds

International Nuclear Information System (INIS)

Parikh, P.; Saini, N.L.; Dalela, S.; Bhardwaj, D.M.; Fernandes, S.; Gupta, R.P.; Garg, K.B.

2003-01-01

We have performed XAFS, EDAX and AFM studies on some natural and synthetic emeralds. While the XAFS results yield information on changes in the valence of the Cr ion and the n-n distance the AFM is used to determine the areal atomic density on surface of the crystals. It is a pilot study to explore if the three techniques can offer a possible way of distinguishing between the natural and synthetic emeralds and the results are promising

Larch: An Analysis Package for XAFS and Related Spectroscopies

International Nuclear Information System (INIS)

Newville, Matthew

2013-01-01

LARCH, a package of analysis tools for XAFS and related spectroscopies is presented. A complete rewrite of the ifeffit package, the initial release of larch preserves the core XAFS analysis procedures such as normalization, background subtraction, Fourier transforms, fitting of XANES spectra, and fitting of experimental spectra to a sum of feff Paths, with few algorithmic changes made in comparison to IFEFFIT. LARCH is written using Python and its packages for scientific programming, which gives significant improvements over IFEFFIT in the ability to handle multi-dimensional and large data sets, write complex analysis scripts, visualize data, add new functionality, and customize existing capabilities. Like the earlier version, larch can run from an interactive command line or in batch-mode, but larch can also be run as a server and accessed from clients using standard inter-process communication techniques available in a variety of computer languages. larch is freely available under an open source license. Examples of using larch are shown, future directions for development are discussed, and collaborations for adding new capabilities are actively sought.

Adaptive, full-spectrum solar energy system

Science.gov (United States)

Muhs, Jeffrey D.; Earl, Dennis D.

2003-08-05

An adaptive full spectrum solar energy system having at least one hybrid solar concentrator, at least one hybrid luminaire, at least one hybrid photobioreactor, and a light distribution system operably connected to each hybrid solar concentrator, each hybrid luminaire, and each hybrid photobioreactor. A lighting control system operates each component.

Full Spectrum Diffused and Beamed Solar Energy Application Using Optical Fibre

OpenAIRE

Majumdar, M. R. Dutta; Das, Debasish

2007-01-01

Existing solar energy application systems use small fraction of full spectrum of solar energy. So attempts are made to show how full spectrum solar energy can be used for diffused and beamed form of incident solar energy. Luminescent Solar Concentrator (LSC) principle with optical fibre in diffused sun light and dielectric mirror separation technique with optical fibre in beamed form are discussed. Comparison of both the cases are done. Keywords: full spectrum, solar photonics, diffused solar...

Uranium XAFS analysis of kidney from rats exposed to uranium.

Science.gov (United States)

Kitahara, Keisuke; Numako, Chiya; Terada, Yasuko; Nitta, Kiyohumi; Shimada, Yoshiya; Homma-Takeda, Shino

2017-03-01

The kidney is the critical target of uranium exposure because uranium accumulates in the proximal tubules and causes tubular damage, but the chemical nature of uranium in kidney, such as its chemical status in the toxic target site, is poorly understood. Micro-X-ray absorption fine-structure (µXAFS) analysis was used to examine renal thin sections of rats exposed to uranyl acetate. The U L III -edge X-ray absorption near-edge structure spectra of bulk renal specimens obtained at various toxicological phases were similar to that of uranyl acetate: their edge position did not shift compared with that of uranyl acetate (17.175 keV) although the peak widths for some kidney specimens were slightly narrowed. µXAFS measurements of spots of concentrated uranium in the micro-regions of the proximal tubules showed that the edge jump slightly shifted to lower energy. The results suggest that most uranium accumulated in kidney was uranium (VI) but a portion might have been biotransformed in rats exposed to uranyl acetate.

Advantages of an Automated Chemical Processor for XAFS Analysis of Novel Materials

International Nuclear Information System (INIS)

Calvin, S.; Carpenter, E. E.

2007-01-01

For synthetic chemists and material scientists, XAFS analysis is typically used after promising samples have already been identified. This is not an inherent limitation of the technique, which can be applied in a crude fashion quite rapidly, but is rather an artifact of the separation of laboratory from synchrotron, and of the nature of the allocation of beam time. One way around these difficulties is to use automated chemical processors; preferably with identical machines at the home institution and at the beamline. This allows identical samples to be synthesized on demand in both locations, so that the characterization resources of the home institution's laboratory can be applied immediately to samples synthesized at the beamline. In addition, the processor can be run in a combinatorial mode, so that the XAFS of many possible synthesis results are examined in a short time. Finally, spectra possessing features of interest can be identified by software, and those syntheses singled out for further study

Combat Training Centers: Training for Full-Spectrum Operations?

National Research Council Canada - National Science Library

Diano, Oscar F

2007-01-01

The changing strategic environment has necessitated a shift in Army training from traditional maneuver warfare to full-spectrum operations to defeat irregular, catastrophic, and disruptive challenges more effectively...

XAFS studies of ytterbium doped lead-telluride

International Nuclear Information System (INIS)

Radisavljevic, I.; Novakovic, N.; Romcevic, N.; Manasijevic, M.; Mahnke, H.-E.; Ivanovic, N.

2010-01-01

X-ray Absorption Fine Structure (XAFS) measurements were performed on uniformly doped PbTe:Yb (1.3 at.%) at all elemental absorption edges and the analysis of the results has provided precise information on the local structure around each atom. From the near edge part of the absorption spectra it was determined that Yb is in the mixed valent state, which is predominantly divalent with a small trivalent contribution. The analysis of the high energy region of the absorption spectra revealed that Yb incorporation causes deformation of the host PbTe lattice, manifested through extension of all the nearest-, and next-nearest neighbour distances.

Full spectrum analysis in environmental monitoring

International Nuclear Information System (INIS)

Reinhardt, Sascha; Hartmann, Soeren; Pimpl, Richard

2015-01-01

In the environmental monitoring spectroscopic gamma detectors are frequently used. The motivation to use spectroscopic gamma detectors is the higher sensitivity and specific spectral information. For the analysis often the photo peaks of the gamma spectrum are used to identify the nuclide. These methods are very reliable, robust and well developed but using only the photo peak means also to use only a fraction of the available information. Doing a full spectrum analysis based on principle components obtained from NASVD for description of the radiation background and adjustment calculations are a possible analysis method which may provide advantages compared to a peak based analysis when used for a continuous environmental monitoring. An analysis example is shown and discussed with a measured time series of gamma spectra obtained from a spectroscopic gamma detector SARA IGS710 with a NaI(Tl) scintillator as it is used in the environmental monitoring.

Full spectrum analysis in environmental monitoring

International Nuclear Information System (INIS)

Reinahrdt, S.; Hartmann, S.; Pimpl, R.

2014-01-01

In the environmental monitoring spectroscopic gamma detectors are frequently used. The motivation to use spectroscopic gamma detectors is the higher sensitivity and specific spectral information. For the analysis often the photo peaks of the gamma spectrum are used to identify the nuclide. These methods are very reliable, robust and well developed but using only the photo peak means also to use only a fraction of the available information. Doing a full spectrum analysis based on principal components obtained from NASVD for description of the radiation background and adjustment calculations are a possible analysis method, which may provide advantages compared to a peak based analysis when used for a continuous environmental monitoring. An analysis example is shown and discussed with a measured time series of gamma spectra obtained from a spectroscopic gamma detector SARA IGS710 with a NaI(Tl) scintillator as it is used in the environmental monitoring. (authors)

PREFACE: The 15th International Conference on X-ray Absorption Fine Structure (XAFS15)

Science.gov (United States)

Wu, Z. Y.

2013-04-01

The 15th International Conference on X-ray Absorption Fine Structure (XAFS15) was held on 22-28 July 2012 in Beijing, P. R. China. About 340 scientists from 34 countries attended this important international event. Main hall Figure 1. Main hall of XAFS15. The rapidly increasing application of XAFS to the study of a large variety of materials and the operation of the new SR source led to the first meeting of XAFS users in 1981 in England. Following that a further 14 International Conferences have been held. Comparing a breakdown of attendees according to their national origin, it is clear that participation is spreading to include attendees from more and more countries every year. The strategy of development in China of science and education is increasing quickly thanks to the large investment in scientific and technological research and infrastructure. There are three Synchrotron Radiation facilities in mainland China, Hefei Light Source (HLS) in the National Natural Science Foundation of China (NSRL), Beijing Synchrotron Radiation Facility (BSRF) in the Institute of High Energy Physics, and Shanghai Synchrotron Radiation Facility (SSRF) in the Shanghai Institute of Applied Physics. More than 10000 users and over 5000 proposals run at these facilities. Among them, many teams from the USA, Japan, German, Italy, Russia, and other countries. More than 3000 manuscript were published in SCI journals, including (incomplete) Science (7), Nature (10), Nature Series (7), PNAS (3), JACS (12), Angew. Chem. Int. Ed. (15), Nano Lett. (2), etc. In XAFS15, the participants contributed 18 plenary invited talks, 16 parallel invited talks, 136 oral presentations, 12 special talks, and 219 poster presentations. Wide communication was promoted in the conference halls, the classical banquet restaurant, and the Great Wall. Parallel hallCommunicationPoster room Figure 2. Parallel hallFigure 3. CommunicationFigure 4. Poster room This volume contains 136 invited and contributed papers

X-ray absorption fine structure (XAFS) spectroscopy: a tool for structural studies in material sciences (abstract)

International Nuclear Information System (INIS)

Akhtar, M.J.

2011-01-01

XAFS spectroscopy has revealed itself as a powerful technique for structural characterization of the local atomic environment of individual atomic species, including bond distances, coordination numbers and type of nearest neighbors surrounding the central atom. This technique is particularly useful for materials that show considerable structural and chemical disorder. XAFS spectroscopy has found extensive applications in determining the local atomic and electronic structure of the absorbing centers (atoms) in the materials science, physics, chemistry, biology and geophysics. X-ray absorption edges contain a variety of information on the chemical state and the local structure of the absorbing atom. On the higher energy side of an absorption edge fine structure is observed due to backscattering of the emitted photoelectron. The post-edge region can be divided into two parts. The X-ray Absorption Near Edge Structure (XANES) which extends up to 50 eV of an absorption edge, the spectrum is interpreted in terms of the appropriate components of the local density of states, which would be expected to be sensitive to the valence state of the atom. The intensity, shape and location of the absorption edge features provide information on the valence state, electronic structure and coordination geometry of the absorbing atom.The Extended X-ray Absorption Fine Structure (EXAFS) region is dominated by the single scattering processes and extends up to 1000 eV above the edge and provides information on the radial distribution (coordination number, radial distance and type of neighboring atoms) around the central atom. The results on perovskite based and spinel ferrites systems will be presented, where valence state and cation distributions are determined; the present study will show focus on SrFeO/sub 3/, MnFe/sub 2/O/sub 4/ and Zn/sub 1-x/Ni/sub x/Fe/sub 2/O/sub 4/ materials. (author)

Electrochromic characteristics of a nickel borate thin film investigated by in situ XAFS and UV/vis spectroscopy

International Nuclear Information System (INIS)

Yoshida, Masaaki; Iida, Tsuyoshi; Mineo, Takehiro

2014-01-01

The electrochromic transition of a nickel borate thin film between colorless and brown was examined by means of in situ XAFS and UV/vis spectroscopy. The XAFS spectra showed that the average valence state of the nickel species in the film changed from +2.1 to +3.8 following the application of an electrode potential. Additionally, a broad peak at 700 nm was observed during in situ UV/vis absorption measurements on the application of a positive potential. These results suggest that the nickel borate film reversibly forms a NiOOH structure with a domain size of several nanometers during the electrochromic reaction. (author)

XAFS Studies of Fe Doped PhTiO3 Nanoparticles

International Nuclear Information System (INIS)

Shibata, Tomohiro; Chattopadhyay, Soma; Lin Bin; Palkar, V. R.

2007-01-01

Fe K and Ti K edge XAFS studies are reported on Fe doped PbTiO3 nanoparticles down to the 10 nm size. Fe forms Fe3+ ions and substitute for Ti4+ ions. For 18 nm nanoparticles, the Fe and Ti environment is found to be quite different. For PbFe0.5Ti0.5O3, locally the structure remains distorted from bulk to 10 nm size although the average structure changes

Position monitor of SR beam on XAFS experimental station in BSRF

International Nuclear Information System (INIS)

Chen Xianneng; Xie Yaning; Hu Tiandou; Jin Yalan; Huang Daxian

1995-01-01

A monitor of density and position of SR (Synchrotron Radiation) beam is built on XAFS (X-ray Absorption Fine Structure) experimental station in BSRF (Beijing Synchrotron Radiation Facility). It is composed of the beam slit and its drivers, weak current amplifiers, computing amplifier for coordinate of the beam position and display with RS-232 interface. The equipment can be used for other measurement fields related with current and voltage

Characterization of Iraq-luster painted pottery by XRF and XAFS analysis

International Nuclear Information System (INIS)

Miura, Sanae; Kato, Norihiro; Nakai, Izumi; Shindo, Yoko

2009-01-01

Luster is one of the most interesting Islamic ceramic decorations. Their origins are known to be due to a nanostructured thin layer formed by metallic copper and silver nanocrystals. The chemical composition of the glazes and decorations of Iraq luster potteries stored in IDEMITSU museum of art were studied using XRF quantitative analysis and XRF imaging. Moreover, the local environment of copper and silver dispersed in the glaze were analyzed by means of XAFS analysis. The white glaze of Iraq luster pottery can be classified into alkali-lime glaze and alkali-lead-lime glaze according to their contents of PbO and SnO 2 . The present XRF analysis revealed that the almost all samples belong to alkali-lead-lime glaze. In addition, it is found from XRF imaging that different copper/silver ratios affect the color of decorations. Cu K-edge and Ag K-edge XAFS spectra of these shards were measured to reveal the chemical state of copper and silver. Presence of metallic copper is found in the red luster. In olive green and brown luster, copper is almost present in the Cu (I) state. Also, in dark brown luster, both Cu (I) and Cu (II) states are found, while, silver always exists in the metallic form independent of the color. (author)

Research for new materials manufacturing using XAFS. Around the non-crystal materials

International Nuclear Information System (INIS)

Sakurai, Masaki

2000-01-01

In the new materials manufacturing it becomes important to control its structure in nano-scale. The fine structure analysis using XAFS with the proton factory is also useful for the manufacturing. The following two items are reported. 1) The new materials manufacturing from amorphous state is very useful through the control of super cooling state and through the doping of a very small amount of additive elements; Radial distribution analysis using XAFS is important for understanding of the concentration fluctuation in the amorphous. 2) The new materials manufacturing from the cluster as a raw materials; Manufacturing the new materials from the cluster is very useful method through the condensation of the cluster of through the distribution the cluster in the matrix. The magic number clusters such as Me9O6, Me13O8, Me22O12 and Me43O20 (Me=Fe, Co, Ni) are observed they are much stable in comparing with other clusters. These magic number clusters are expected to be useful for the new material manufacturing. For the control of the cluster formation the in-situ analysis using LVCS is important in understanding the cluster formation process. (H. Katsuta)

ADAPTIVE FULL-SPECTRUM SOLOR ENERGY SYSTEMS

Energy Technology Data Exchange (ETDEWEB)

Byard D. Wood

2004-04-01

This RD&D project is a three year team effort to develop a hybrid solar lighting (HSL) system that transports solar light from a paraboloidal dish concentrator to a luminaire via a large core polymer fiber optic. The luminaire can be a device to distribute sunlight into a space for the production of algae or it can be a device that is a combination of solar lighting and electric lighting. A benchmark prototype system has been developed to evaluate the HSL system. Sunlight is collected using a one-meter paraboloidal concentrator dish with two-axis tracking. A secondary mirror consisting of eight planar-segmented mirrors directs the visible part of the spectrum to eight fibers (receiver) and subsequently to eight luminaires. This results in about 8,200 lumens incident at each fiber tip. Each fiber can illuminate about 16.7 m{sup 2} (180 ft{sup 2}) of office space. The IR spectrum is directed to a thermophotovoltaic (TPV) array to produce electricity. During this reporting period, the project team made advancements in the design of the second generation (Alpha) system. For the Alpha system, the eight individual 12 mm fibers have been replaced with a centralized bundle of 3 mm fibers. The TRNSYS Full-Spectrum Solar Energy System model has been updated and new components have been added. The TPV array and nonimaging device have been tested and progress has been made in the fiber transmission models. A test plan was developed for both the high-lumen tests and the study to determine the non-energy benefits of daylighting. The photobioreactor team also made major advancements in the testing of model scale and bench top lab-scale systems.

New routes of XAFS with the low emittance storage rings

International Nuclear Information System (INIS)

Fontaine, A.

1993-01-01

New routes of XAFS should come from the extreme focusing and the polarization tunability of the new storage rings. It is certainly of interest to recall that fundamental ideas in X-ray absorption spectroscopy should come from direct soft X-ray excitations, currently accessible with the national facilities but also via inelastic scattering by electronic excitations more relevant of the new storage rings. Because of the ESRF proximity, references come from the European development, but it is only due to my ignorance if pertinent quotations of the American and Japanese efforts are missing. (author)

Convergence of the multiple scattering expansion in XAFS and XANES

International Nuclear Information System (INIS)

Rehr, J.J.

1992-01-01

The convergence of the multiple-scattering expansion of XAFS and XANES by explicit path-bypath calculations. The approach is based on the fast scattering matrix formalism of Rehr and Albers, together with an automated path finder and filters that exclude negligible paths. High-order scattering terms are found to be essential, especially at low energies. Several factors including the magnitude of curved wave scattering amplitudes, inelastic losses and multiple-scattering Debye-Waller factors control convergence of the expansion. The convergence is illustrated explicitly for the case of diatomic molecules

Full-spectrum volumetric solar thermal conversion via photonic nanofluids.

Science.gov (United States)

Liu, Xianglei; Xuan, Yimin

2017-10-12

Volumetric solar thermal conversion is an emerging technique for a plethora of applications such as solar thermal power generation, desalination, and solar water splitting. However, achieving broadband solar thermal absorption via dilute nanofluids is still a daunting challenge. In this work, full-spectrum volumetric solar thermal conversion is demonstrated over a thin layer of the proposed 'photonic nanofluids'. The underlying mechanism is found to be the photonic superposition of core resonances, shell plasmons, and core-shell resonances at different wavelengths, whose coexistence is enabled by the broken symmetry of specially designed composite nanoparticles, i.e., Janus nanoparticles. The solar thermal conversion efficiency can be improved by 10.8% compared with core-shell nanofluids. The extinction coefficient of Janus dimers with various configurations is also investigated to unveil the effects of particle couplings. This work provides the possibility to achieve full-spectrum volumetric solar thermal conversion, and may have potential applications in efficient solar energy harvesting and utilization.

Full spectrum of Lyapunov exponents in gauge field theories

International Nuclear Information System (INIS)

Biro, T.S.; Markum, H.; Pullirsch, R.

2003-01-01

Full text: Results are presented for the full spectrum of Lyapunov exponents of the compact U(1) gauge system in classical field theory. Instead of the determination of the largest Lyapunov exponent by the rescaling method we now use the monodromy matrix approach. The Lyapunov spectrum L i is expressed in terms of the eigenvalues Λ i of the monodromy matrix M. In the confinement phase the eigenvalues lie on either the real or on the imaginary axes. This is a nice illustration of a strange attractor of a chaotic system. Positive Lyapunov exponents eject the trajectories from oscillating orbits provided by the imaginary eigenvalues. Negative Lyapunov exponents attract the trajectories keeping them confined in the basin. Latest studies concern the time (in)dependence of the monodromy matrix. Further, we show that monopoles are created and annihilated in pairs as a function of real time in access to a fixed average monopole number. (author)

Review of Full Spectrum of Services offered at Special Libraries

Directory of Open Access Journals (Sweden)

Fatemeh Assian

2009-12-01

Full Text Available   Special libraries fill a very important role in providing services to corporate users. The necessity to identify and promote the full spectrum of services offered by these type of libraries is felt more than ever. The present paper attempts to describe these services by reviewing the literature published in this respect.

The diffractive achromat full spectrum computational imaging with diffractive optics

KAUST Repository

Peng, Yifan

2016-07-11

Diffractive optical elements (DOEs) have recently drawn great attention in computational imaging because they can drastically reduce the size and weight of imaging devices compared to their refractive counterparts. However, the inherent strong dispersion is a tremendous obstacle that limits the use of DOEs in full spectrum imaging, causing unacceptable loss of color fidelity in the images. In particular, metamerism introduces a data dependency in the image blur, which has been neglected in computational imaging methods so far. We introduce both a diffractive achromat based on computational optimization, as well as a corresponding algorithm for correction of residual aberrations. Using this approach, we demonstrate high fidelity color diffractive-only imaging over the full visible spectrum. In the optical design, the height profile of a diffractive lens is optimized to balance the focusing contributions of different wavelengths for a specific focal length. The spectral point spread functions (PSFs) become nearly identical to each other, creating approximately spectrally invariant blur kernels. This property guarantees good color preservation in the captured image and facilitates the correction of residual aberrations in our fast two-step deconvolution without additional color priors. We demonstrate our design of diffractive achromat on a 0.5mm ultrathin substrate by photolithography techniques. Experimental results show that our achromatic diffractive lens produces high color fidelity and better image quality in the full visible spectrum. © 2016 ACM.

Train-the-Trainer Package for the Full Spectrum Warrior Game

National Research Council Canada - National Science Library

Centric, James

2004-01-01

.... Full Spectrum Warrior (FSW), built for use with Microsoft's X-Box game console system, was developed to provide Infantry squad leaders with the opportunity to practice making tactical decisions and executing the troop-leading...

The diffractive achromat full spectrum computational imaging with diffractive optics

KAUST Repository

Peng, Yifan; Fu, Qiang; Heide, Felix; Heidrich, Wolfgang

2016-01-01

dispersion is a tremendous obstacle that limits the use of DOEs in full spectrum imaging, causing unacceptable loss of color fidelity in the images. In particular, metamerism introduces a data dependency in the image blur, which has been neglected

Normalized noise power spectrum of full field digital mammography detector system

International Nuclear Information System (INIS)

Norriza Mohd Isa; Wan Muhamad Saridan Wan Hassan

2009-01-01

Full text: A method to measure noise power spectrum of a full field digital mammography system is presented. The effect of X-ray radiation dose, size and configuration of region of interest on normalized noise power spectrum (NNPS) was investigated. Flat field images were acquired using RQA-M2 beam quality technique (Mo/Mo anode-filter, 28 kV, 2 mm Al) with different clinical radiation doses. The images were cropped at about 4 cm from the edge of the breast wall and then divided into different size of non-overlapping or overlapping segments. NNPS was determined through de trending, 2-D fast Fourier transformation and normalization. Our measurement shows that high radiation dose gave lower NNPS at a specific beam quality. (author)

The 16th International Conference on X-ray Absorption Fine Structure (XAFS16)

Science.gov (United States)

Grunwaldt, J.-D.; Hagelstein, M.; Rothe, J.

2016-05-01

This preface of the proceedings volume of the 16th International Conference on X- ray Absorption Fine Structure (XAFS16) gives a glance on the five days of cutting-edge X-ray science which were held in Karlsruhe, Germany, August 23 - 28, 2015. In addition, several satellite meetings took place in Hamburg, Berlin and Stuttgart, a Sino-German workshop, three data analysis tutorials as well as special symposia on industrial catalysis and XFELs were held at the conference venue.

X-ray Absorption Fine Structure (XAFS) Studies of Oxide Glasses—A 45-Year Overview

Science.gov (United States)

Zanotto, Edgar Dutra

2018-01-01

X-ray Absorption Fine Structure (XAFS) spectroscopy has been widely used to characterize the short-range order of glassy materials since the theoretical basis was established 45 years ago. Soon after the technique became accessible, mainly due to the existence of Synchrotron laboratories, a wide range of glassy materials was characterized. Silicate glasses have been the most studied because they are easy to prepare, they have commercial value and are similar to natural glasses, but borate, germanate, phosphate, tellurite and other less frequent oxide glasses have also been studied. In this manuscript, we review reported advances in the structural characterization of oxide-based glasses using this technique. A focus is on structural characterization of transition metal ions, especially Ti, Fe, and Ni, and their role in different properties of synthetic oxide-based glasses, as well as their important function in the formation of natural glasses and magmas, and in nucleation and crystallization. We also give some examples of XAFS applications for structural characterization of glasses submitted to high pressure, glasses used to store radioactive waste and medieval glasses. This updated, comprehensive review will likely serve as a useful guide to clarify the details of the short-range structure of oxide glasses. PMID:29382102

Normalized Noise Power Spectrum of Full Field Digital Mammography System

International Nuclear Information System (INIS)

Isa, Norriza Mohd; Wan Hassan, Wan Muhamad Saridan

2010-01-01

A method to measure noise power spectrum of a full field digital mammography system is presented. The effect of X-ray radiation dose, size and configuration of region of interest on normalized noise power spectrum (NNPS) was investigated. Flat field images were acquired using RQA-M2 beam quality technique (Mo/Mo anode-filter, 28 kV, 2 mm Al) with different clinical radiation doses. The images were cropped at about 4 cm from the edge of the breast wall and then divided into different size of non-overlapping or overlapping segments. NNPS was determined through detrending, 2-D fast Fourier transformation and normalization. Our measurement shows that high radiation dose gave lower NNPS at a specific beam quality.

Normalized noise power spectrum of full field digital mammography system

International Nuclear Information System (INIS)

Norriza Mohd Isa; Wan Muhamad Saridan Wan Hassan

2009-01-01

A method to measure noise power spectrum of a full field digital mammography system is presented. The effect of X-ray radiation dose, size and configuration of region of interest on normalized noise power spectrum (NNPS) was investigated. Flat field images were acquired using RQA-M2 beam quality technique (Mo/Mo anode-filter, 28 kV, 2 mm Al) with different clinical radiation doses. The images were cropped at about 4 cm from the edge of the breast wall and then divided into different size of non-overlapping or overlapping segments. NNPS was determined through detrending, 2-D fast Fourier transformation and normalization. Our measurement shows that high radiation dose gave lower NNPS at a specific beam quality. (Author)

A Comparative XAFS Study of Gold-thiolate Nanoparticles and Nanoclusters

International Nuclear Information System (INIS)

Chevrier, D M; Chatt, A; Zhang, P; Sham, T K

2013-01-01

Tiopronin-capped gold nanoparticles and gold nanoclusters of sizes 3.0 and 1.5 nm, respectively, were investigated with XAFS at the gold L 3 -edge. The specific EXAFS fitting procedure is discussed for obtaining reliable fit parameters for each system. The difficulties and challenges faced when analysing EXAFS data for gold nanoparticles and nanoclusters are also mentioned. Fitting results for gold nanoparticles reveal a small amount of surface Au-thiolate interactions with a large Au-Au metal core. For gold nanoclusters, only a one-shell fit was obtainable. Instead of Au-Au metal core, long-range interactions are expected for gold nanoclusters. Tiopronin-capped gold nanoclusters are proposed to be polymeric in nature, which helps explain the observed red luminescence.

XAFS Analysis of Local Structure around Ce in Ca3Sc2Si3O12:Ce Phosphor for White LEDs

International Nuclear Information System (INIS)

Akai, Toshio; Shigeiwa, Motoyuki; Okamoto, Kaoru; Shimomura, Yasuo; Kijima, Naoto; Honma, Tetsuo

2007-01-01

We have studied the local structure around Ce atom in Ca3Sc2Si3O12 host crystal, which has been developed as a new green phosphor for white light emitting diodes (LEDs). As the local structure and chemical environment of the dopant atom are very important to improve the performance of the phosphor, we have used XAFS to get chemical and structural information around the Ce dopant. The XANES spectrum of the Ce LIII-edge reveals that the Ce atom is trivalent in Ca3Sc2Si3O12. There are two kinds of possible Ce substitution sites, Ca site and Sc site, in garnet type Ca3Sc2Si3O12 crystal structure. The Ce atom is found to be at the Ca site in the host crystal by the comparison of the Fourier transform of Ce K-edge EXAFS spectrum with those of Ca and Sc K-edge EXAFS spectra. The theoretical analysis with FEFF also clarified the Ce substitution at the Ca site. Furthermore, the result of the analysis indicates the structural disorder around Ca and Si atoms at 3.75 A. It is possible that there are some defects around the Ca and Si atoms at 3.75 A to compensate the excess positive charge by introduced Ce3+ at the Ca2+ site

Study on the structure of Co/ZrO2-SiO2 catalysts by XAFS

International Nuclear Information System (INIS)

Gao Haiyan; Xiang Hongwei; Li Yongwang; Sun Yuhan; Liu Tao; Xie Yaning; Hu Tiandou

2002-01-01

The Co-based catalysts have been extensively used in converting CO to longer chain hydrocarbons which can then be hydrocracked to diesel oil with high grade. SiO 2 is one of the most commonly used carriers for Co-based catalysts. It is showed that commercial silica carrier after modification can lead to much high reaction activity and selectivity to heavy hydrocarbons. But the structure of Co-based catalysts supported on the modified carrier has not been clearly understood. XAFS is used to investigate the change of structure of cobalt species in Co-based catalysts supported on modified carriers. The result from XAFS indicate that the structure of Co-based catalysts supported on modified carrier has certain change in comparison with Co-based catalyst supported on commercial silica. The interaction between carrier and metal is woken in the modified catalysts. Especially, the structure of catalysts after reduction have distinct difference. The extent of reduction in modified catalysts is much more than the catalyst supported on commercial silica. Cobalt species of the catalyst supported commercial silica after reduction dose exist mainly in the form of cobalt metal forms and may exist in the form of Co 2 SiO 4 surface compound

The application of full spectrum gamma-gamma techniques to density/photoelectric cross section logging

International Nuclear Information System (INIS)

Minette, D.C.; Hubner, B.G.; Koudelka, J.C.; Schmidt, M.

1986-01-01

The Compensated Z-Densilog instrument is a new full spectrum gamma-gamma logging instrument, measuring the density and photoelectric cross section (Pe) of the formation. This instrument represents an advancement over present instruments in that the observed gamma spectrum is sent to the surface as a full 256-channel spectrum instead of count rates in a few energy gates. This advancement is made possible by the use of high speed digital electronics which are protected from the high temperatures observed downhole by custom-built flasks. In this paper, the new advanced electronics are considered in some detail. This consideration includes a comparison of full spectrum data acquisition with the multiple discriminator window technique, which is the foundation of the ''few gate'' method. Both of these methods are critiqued based upon electronic stability and the information obtained. The full spectrum provided by high speed electronics facilitates a much more sophisticated data analysis. This data analysis, based on phenomenological model of the instrument (Minette, 1984), includes real time compensation for changes in detector gain and crystal resolution. It also includes a ''four-dimensional'' rib-spine plot, which separates the compensation for mudcake density from the compensation for the Pe of the formation and the mudcake. Also included in the software are real time error minimization and real time decision-making techniques. These techniques maximize the sensitivity of the instrument to the density and Pe of the formation and minimize error due to statistical fluctuations. Gain and resolution compensation completes the data analysis. This compensation virtually eliminates density and Pe errors caused by changing gain and resolution

Prognoses of prospective areas for uranium metallogenesis with full-spectrum information of airborne gamma-ray survey

International Nuclear Information System (INIS)

Hu Mingkao; Shen Zhengxin; Li Binghai; Cai Genqing

2010-01-01

This paper briefly introduces the development of airborne radioactive survey and the background of carrying out full-spectrum study. It also introduces the method, standard and application example of using the full-spectrum information of airborne gamma spectrum to predict U-metallogenic prospective areas. The field checking has found that uranium in the water of the prospective area is three magnitude higher than that in the normal area. The developmment and the application of this method will play a multiplier role in reusing the library stored data evaluating uranium resource potential in our Country. (authors)

XAFS studies of monodisperse Au nanoclusters formation in the etching process

International Nuclear Information System (INIS)

Yang, Lina; Huang, Ting; Liu, Wei; Bao, Jie; Huang, Yuanyuan; Cao, Yuanjie; Yao, Tao; Sun, Zhihu; Wei, Shiqiang

2016-01-01

Understanding the formation mechanism of gold nanoclusters is essential to the development of their synthetic chemistry. Here, by using x-ray absorption fine-structure (XAFS) spectroscopy, UV-Vis and MS spectra, the formation process of monodisperse Au 13 nanoclusters is investigated. We find that a critical step involving the formation of smaller Au 8 -Au 11 metastable intermediate clusters induced by the HCl + HSR etching of the polydisperse Au n precursor clusters occurs firstly. Then these intermediate species undergo a size-growth to Au 13 cores, followed by a slow structure rearrangement to reach the final stable structure. This work enriches the understanding of cluster formation chemistry and may guide the way towards the design and the controllable synthesis of nanoclusters. (paper)

The full spectrum of ethical issues in dementia care: systematic qualitative review.

Science.gov (United States)

Strech, Daniel; Mertz, Marcel; Knüppel, Hannes; Neitzke, Gerald; Schmidhuber, Martina

2013-06-01

Integrating ethical issues in dementia-specific training material, clinical guidelines and national strategy plans requires an unbiased awareness of all the relevant ethical issues. To determine systematically and transparently the full spectrum of ethical issues in clinical dementia care. We conducted a systematic review in Medline (restricted to English and German literature published between 2000 and 2011) and Google books (with no restrictions). We applied qualitative text analysis and normative analysis to categorise the spectrum of ethical issues in clinical dementia care. The literature review retrieved 92 references that together mentioned a spectrum of 56 ethical issues in clinical dementia care. The spectrum was structured into seven major categories that consist of first- and second-order categories for ethical issues. The systematically derived spectrum of ethical issues in clinical dementia care presented in this paper can be used as training material for healthcare professionals, students and the public for raising awareness and understanding of the complexity of ethical issues in dementia care. It can also be used to identify ethical issues that should be addressed in dementia-specific training programmes, national strategy plans and clinical practice guidelines. Further research should evaluate whether this new genre of systematic reviews can be applied to the identification of ethical issues in other cognitive and somatic diseases. Also, the practical challenges in addressing ethical issues in training material, guidelines and policies need to be evaluated.

FAULT DIAGNOSIS IN ROTATING MACHINE USING FULL SPECTRUM OF VIBRATION AND FUZZY LOGIC

Directory of Open Access Journals (Sweden)

ROGER R. DA SILVA

2017-11-01

Full Text Available Industries are always looking for more efficient maintenance systems to minimize machine downtime and productivity liabilities. Among several approaches, artificial intelligence techniques have been increasingly applied to machine diagnosis. Current paper forwards the development of a system for the diagnosis of mechanical faults in the rotating structures of machines, based on fuzzy logic, using rules foregrounded on the full spectrum of the machine´s complex vibration signal. The diagnostic system was developed in Matlab and it was applied to a rotor test rig where different faults were introduced. Results showed that the diagnostic system based on full spectra and fuzzy logic is capable of identifying with precision different types of faults, which have similar half spectrum. The methodology has a great potential to be implemented in predictive maintenance programs in industries and may be expanded to include the identification of other types of faults not covered in the case study under analysis.

High Efficiency XAFS Data Collection With Sub-Nanosecond Time Resolution

International Nuclear Information System (INIS)

Brewe, Dale; Heald, Steve M.; Stern, Edward; Beck, Kenneth M.; Feng, Yejun

2004-01-01

Synchrotron-based laser pump/x-ray probe experiments on a ns or faster time scale have typically used ultrafast lasers suffering from the limitation of low repetition rates on the order of 1-10 kHz. This severely limits the data collection efficiency, since the x-ray bunches repeat at a much higher rate. This is particularly critical for XAFS experiments, which require very large S/N ratios (∼ 104 or better) to extract useful EXAFS far above the absorption edge. PNC-CAT has developed an apparatus based on a laser repeating at the rate of the APS bunch repetition frequency of 272 kHz, allowing an increase in data collection efficiency by two orders of magnitude. We have used this apparatus to obtain preliminary results for the time-resolved EXAFS from a 200nm thick polycrystalline Ge film which has been heated by the laser

X-ray absorption fine structure (XAFS) studies of cobalt silicide thin films

International Nuclear Information System (INIS)

Naftel, S.J.; Coulthard, I.; Hu, Y.; Sham, T.K.; Zinke-Allmang, M.

1998-01-01

Cobalt silicide thin films, prepared on Si(100) wafers, have been studied by X-ray absorption near edge structures (XANES) at the Si K-, L 2,3 - and Co K-edges utilizing both total electron (TEY) and fluorescence yield (FLY) detection as well as extended X-ray absorption fine structure (EXAFS) at the Co K-edge. Samples made using DC sputter deposition on clean Si surfaces and MBE were studied along with a bulk CoSi 2 sample. XANES and EXAFS provide information about the electronic structure and morphology of the films. It was found that the films studied have essentially the same structure as bulk CoSi 2 . Both the spectroscopy and materials characterization aspects of XAFS (X-ray absorption fine structures) are discussed

Encoded diffractive optics for full-spectrum computational imaging

KAUST Repository

Heide, Felix; Fu, Qiang; Peng, Yifan; Heidrich, Wolfgang

2016-01-01

Diffractive optical elements can be realized as ultra-thin plates that offer significantly reduced footprint and weight compared to refractive elements. However, such elements introduce severe chromatic aberrations and are not variable, unless used in combination with other elements in a larger, reconfigurable optical system. We introduce numerically optimized encoded phase masks in which different optical parameters such as focus or zoom can be accessed through changes in the mechanical alignment of a ultra-thin stack of two or more masks. Our encoded diffractive designs are combined with a new computational approach for self-calibrating imaging (blind deconvolution) that can restore high-quality images several orders of magnitude faster than the state of the art without pre-calibration of the optical system. This co-design of optics and computation enables tunable, full-spectrum imaging using thin diffractive optics.

Encoded diffractive optics for full-spectrum computational imaging

KAUST Repository

Heide, Felix

2016-09-16

Diffractive optical elements can be realized as ultra-thin plates that offer significantly reduced footprint and weight compared to refractive elements. However, such elements introduce severe chromatic aberrations and are not variable, unless used in combination with other elements in a larger, reconfigurable optical system. We introduce numerically optimized encoded phase masks in which different optical parameters such as focus or zoom can be accessed through changes in the mechanical alignment of a ultra-thin stack of two or more masks. Our encoded diffractive designs are combined with a new computational approach for self-calibrating imaging (blind deconvolution) that can restore high-quality images several orders of magnitude faster than the state of the art without pre-calibration of the optical system. This co-design of optics and computation enables tunable, full-spectrum imaging using thin diffractive optics.

Sharing the Licensed Spectrum of Full-Duplex Systems using Improper Gaussian Signaling

KAUST Repository

Gaafar, Mohamed; Amin, Osama; Abediseid, Walid; Alouini, Mohamed-Slim

2016-01-01

Sharing the spectrum with in-band full-duplex (FD) primary users (PU) is a challenging and interesting problem in the underlay cognitive radio (CR) systems. The self-inteference introducsed at the primary network may dramatically impede the secondary user (SU) opportunity to access the spectrum. In this work, we attempt to tackle this problem through the use of so called improper Gaussian signaling (IGS). Such a signaling technique has demonstrated its superiority in improving the overall performance in interference limited networks. Particularly, we assume a system with a SU pair working in half-duplex mode that uses IGS while the FD PU pair implements the regular proper Gaussiam signaling techniques. Frist, we derive a closed form expression for the SU outage probability while maintaining the required PU quality-of-service based on the average channel state information. Finally, we provide some numerical results that validate the tightness of the PU outage probability bound and demonstrate the advantage of employing IGS to the SU in order to access the spectrum of the FD PU.

Sharing the Licensed Spectrum of Full-Duplex Systems using Improper Gaussian Signaling

KAUST Repository

Gaafar, Mohamed

2016-01-06

Sharing the spectrum with in-band full-duplex (FD) primary users (PU) is a challenging and interesting problem in the underlay cognitive radio (CR) systems. The self-inteference introducsed at the primary network may dramatically impede the secondary user (SU) opportunity to access the spectrum. In this work, we attempt to tackle this problem through the use of so called improper Gaussian signaling (IGS). Such a signaling technique has demonstrated its superiority in improving the overall performance in interference limited networks. Particularly, we assume a system with a SU pair working in half-duplex mode that uses IGS while the FD PU pair implements the regular proper Gaussiam signaling techniques. Frist, we derive a closed form expression for the SU outage probability while maintaining the required PU quality-of-service based on the average channel state information. Finally, we provide some numerical results that validate the tightness of the PU outage probability bound and demonstrate the advantage of employing IGS to the SU in order to access the spectrum of the FD PU.

Full-Duplex opportunistic relay selection in future spectrum-sharing networks

KAUST Repository

Khafagy, Mohammad Galal; Alouini, Mohamed-Slim; Aï ssa, Sonia

2015-01-01

We propose and analyze the performance of full-duplex relay selection in primary/secondary spectrum-sharing networks. Contrary to half-duplex relaying, full-duplex relaying (FDR) enables simultaneous listening/forwarding at the secondary relay, thereby allowing for a higher spectral efficiency. However, since the source and relay simultaneously transmit in FDR, their superimposed signal at the primary receiver should now satisfy the existing interference constraint which can considerably limit the secondary network throughput. In this regard, relay selection can offer an adequate solution to boost the secondary throughput while satisfying the imposed interference limit. We first analyze the performance of opportunistic relay selection among a cluster of full-duplex decode-and-forward relays with self-interference by deriving the exact cumulative distribution function of its end-to-end signal-to-noise ratio. Second, we evaluate the end-to-end performance of relay selection with interference constraints due to the presence of a primary receiver. Finally, the presented exact theoretical findings are verified by numerical simulations.

Full-Duplex opportunistic relay selection in future spectrum-sharing networks

KAUST Repository

Khafagy, Mohammad Galal

2015-06-01

We propose and analyze the performance of full-duplex relay selection in primary/secondary spectrum-sharing networks. Contrary to half-duplex relaying, full-duplex relaying (FDR) enables simultaneous listening/forwarding at the secondary relay, thereby allowing for a higher spectral efficiency. However, since the source and relay simultaneously transmit in FDR, their superimposed signal at the primary receiver should now satisfy the existing interference constraint which can considerably limit the secondary network throughput. In this regard, relay selection can offer an adequate solution to boost the secondary throughput while satisfying the imposed interference limit. We first analyze the performance of opportunistic relay selection among a cluster of full-duplex decode-and-forward relays with self-interference by deriving the exact cumulative distribution function of its end-to-end signal-to-noise ratio. Second, we evaluate the end-to-end performance of relay selection with interference constraints due to the presence of a primary receiver. Finally, the presented exact theoretical findings are verified by numerical simulations.

The use of full spectrum digital photography for evidence collection and preservation in cases involving forensic odontology.

Science.gov (United States)

Wright, Franklin D; Golden, Gregory S

2010-09-10

Photography often represents the best method to collect and preserve evidence in forensic cases. This is especially true in forensic odontology with cases involving dental identification, human abuse and, perhaps most significantly, bitemark cases. Basic visible light photography is adequate in most dental identification cases; however, full spectrum digital photography is best utilized to collect all available evidence in cases of human abuse and bitemarks. This paper will discuss the types of photographic evidence that should be collected with various forensic odontological cases and the specific techniques utilized in full spectrum forensic digital photography. The use of full spectrum photography captures the forensic injuries using special techniques recording the injuries in each of the four resultant events that occur when light strikes skin. Copyright 2010 Elsevier Ireland Ltd. All rights reserved.

XAFS Study on TiO2 Photocatalyst Loaded on Zeolite Synthesized from Steel Slag

International Nuclear Information System (INIS)

Kuwahara, Yasutaka; Ohmichi, Tetsutaro; Mori, Kosuke; Katayama, Iwao; Yamashita, Hiromi

2007-01-01

The convenient route for the synthesis of Y-zeolites by utilizing steel slag as a material source was developed. Through hydrothermal treatment, well-crystallized Y-zeolite was obtained. We also synthesized TiO2-loaded Y-zeolites by an impregnation method. The structure of titanium oxide species highly dispersed on the zeolite, which couldn't be detected by XRD patterns, was investigated by XAFS analysis. Photocatalytic activity for decomposition of 2-propanol in liquid phase was found to be enhanced by the hydrophobic surface property of zeolite. It has been demonstrated that the zeolite synthesized from steel slag would be applicable as a promising support of TiO2 photocatalyst

Energy-Dispersive XAFS Study on Reduction Behavior of Pt Supported on TiO2 and Al2O3

International Nuclear Information System (INIS)

Shishido, Testuya; Amano, Fumiaki; Sone, Takayoshi; Yamazoe, Seiji; Tanaka, Tsunehiro; Kato, Kazuo; Teramura, Kentaro

2007-01-01

The dynamic reduction behavior of Pt4+ oxides to Pt0 particles on TiO2 and Al2O3 surface in the presence of hydrogen by means of DXAFS. The platinum oxide on TiO2 is easily reduced even at room temperature. XAFS results suggest that the mechanism of reduction of Pt4+ over TiO2 is different from that over Al2O3

Sharing the Licensed Spectrum of Full-Duplex Systems Using Improper Gaussian Signaling

KAUST Repository

Gaafar, Mohamed

2015-12-01

Sharing the spectrum with in-band full-duplex (FD) primary users (PU) is a challenging and interesting problem in the underlay cognitive radio (CR) systems. The self-interference introduced at the primary network may dramatically impede the secondary user (SU) opportunity to access the spectrum. In this work, we attempt to tackle this problem through the use of the so-called improper Gaussian signaling. Such a signaling technique has demonstrated its superiority in improving the overall performance in interference limited networks. Particularly, we assume a system with a SU pair working in half-duplex mode that uses improper Gaussian signaling while the FD PU pair implements the regular proper Gaussian signaling techniques. First, we derive a closed form expression for the SU outage probability and an upper bound for the PU outage probability. Then, we optimize the SU signal parameters to minimize its outage probability while maintaining the required PU quality-of-service based on the average channel state information. Finally, we provide some numerical results that validate the tightness of the PU outage probability bound and demonstrate the advantage of employing the improper Gaussian signaling to the SU in order to access the spectrum of the FD PU.

Underlay Spectrum Sharing Techniques with In-Band Full-Duplex Systems using Improper Gaussian Signaling

KAUST Repository

Gaafar, Mohamed; Amin, Osama; Abediseid, Walid; Alouini, Mohamed-Slim

2016-01-01

Sharing the spectrum with in-band full-duplex (FD) primary users (PUs) is a challenging and interesting problem in the underlay cognitive radio (CR) systems. The self-interference introduced at the primary network may dramatically impede

Integration of Semiconducting Sulfides for Full-Spectrum Solar Energy Absorption and Efficient Charge Separation.

Science.gov (United States)

Zhuang, Tao-Tao; Liu, Yan; Li, Yi; Zhao, Yuan; Wu, Liang; Jiang, Jun; Yu, Shu-Hong

2016-05-23

The full harvest of solar energy by semiconductors requires a material that simultaneously absorbs across the whole solar spectrum and collects photogenerated electrons and holes separately. The stepwise integration of three semiconducting sulfides, namely ZnS, CdS, and Cu2-x S, into a single nanocrystal, led to a unique ternary multi-node sheath ZnS-CdS-Cu2-x S heteronanorod for full-spectrum solar energy absorption. Localized surface plasmon resonance (LSPR) in the nonstoichiometric copper sulfide nanostructures enables effective NIR absorption. More significantly, the construction of pn heterojunctions between Cu2-x S and CdS leads to staggered gaps, as confirmed by first-principles simulations. This band alignment causes effective electron-hole separation in the ternary system and hence enables efficient solar energy conversion. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Spectrum sharing opportunities of full-duplex systems using improper Gaussian signaling

KAUST Repository

Gaafar, Mohamed

2015-08-01

Sharing the licensed spectrum of full-duplex (FD) primary users (PU) brings strict limitations on the underlay cognitive radio operation. Particularly, the self interference may overwhelm the PU receiver and limit the opportunity of secondary users (SU) to access the spectrum. Improper Gaussian signaling (IGS) has demonstrated its superiority in improving the performance of interference channel systems. Throughout this paper, we assume a FD PU pair that uses proper Gaussian signaling (PGS), and a half-duplex SU pair that uses IGS. The objective is to maximize the SU instantaneous achievable rate while meeting the PU quality-of-service. To this end, we propose a simplified algorithm that optimizes the SU signal parameters, i.e, the transmit power and the circularity coefficient, which is a measure of the degree of impropriety of the SU signal, to achieve the design objective. Numerical results show the merits of adopting IGS compared with PGS for the SU especially with the existence of week PU direct channels and/or strong SU interference channels.

Ni-induced local distortions in La1.85Sr0.15Cu1-yNiyO4 and their relevance to Tc suppression: An angular-resolved XAFS study

International Nuclear Information System (INIS)

Haskel, Daniel; Stern, Edward A.; Polinger, Victor; Dogan, Fatih

2001-01-01

We present results from angular-resolved x-ray-absorption fine-structure (XAFS) measurements at the Ni, La, and Sr K edges of oriented powders of La 1.85 Sr 0.15 Cu 1-y Ni y O 4 , with y=0.01, 0.03, 0.06. A special magnetic alignment procedure allowed us to measure pure c- and ab-oriented XAFS at the Ni K edge in identical fluorescence geometries. Both the x-ray-absorption near-edge structure and the XAFS unequivocally show that the NiO 6 octahedra are contracted along the c axis by ∼0.32 angstrom relative to CuO 6 octahedra while the in-plane distances of NiO 6 and CuO 6 octahedra are the same within 0.01 angstrom. The NiO 6 octahedral contraction drives the average c axis contraction measured by diffraction with increasing content of Ni. The local c axis shows strong spatial fluctuations, due to the different NiO 6 and CuO 6 octahedral configurations and the stronger bonding of a La 3+ ion than a Sr 2+ ion to the O(2) apical oxygens of such octahedra. We discuss the relevance of these findings to the mechanisms of loss of superconductivity at y∼0.03 and hole localization above y∼0.05 by Ni dopants

Gamma-ray Full Spectrum Analysis for Environmental Radioactivity by HPGe Detector

Directory of Open Access Journals (Sweden)

Meeyoung Jeong

2014-12-01

Full Text Available Odyssey, one of the NASA’s Mars exploration program and SELENE (Kaguya, a Japanese lunar orbiting spacecraft have a payload of Gamma-Ray Spectrometer (GRS for analyzing radioactive chemical elements of the atmosphere and the surface. In these days, gamma-ray spectroscopy with a High-Purity Germanium (HPGe detector has been widely used for the activity measurements of natural radionuclides contained in the soil of the Earth. The energy spectra obtained by the HPGe detectors have been generally analyzed by means of the Window Analysis (WA method. In this method, activity concentrations are determined by using the net counts of energy window around individual peaks. Meanwhile, an alternative method, the so-called Full Spectrum Analysis (FSA method uses count numbers not only from full-absorption peaks but from the contributions of Compton scattering due to gamma-rays. Consequently, while it takes a substantial time to obtain a statistically significant result in the WA method, the FSA method requires a much shorter time to reach the same level of the statistical significance. This study shows the validation results of FSA method. We have compared the concentration of radioactivity of 40K, 232Th and 238U in the soil measured by the WA method and the FSA method, respectively. The gamma-ray spectrum of reference materials (RGU and RGTh, KCl and soil samples were measured by the 120% HPGe detector with cosmic muon veto detector. According to the comparison result of activity concentrations between the FSA and the WA, we could conclude that FSA method is validated against the WA method. This study implies that the FSA method can be used in a harsh measurement environment, such as the gamma-ray measurement in the Moon, in which the level of statistical significance is usually required in a much shorter data acquisition time than the WA method.

Full-Scale Spectrum of Boundary-Layer Winds

DEFF Research Database (Denmark)

Larsén, Xiaoli Guo; Larsen, Søren Ejling; Lundtang Petersen, Erik

2016-01-01

and microscale gives the observed spectrum in the gap range, leading to a suggestion that mesoscale and microscale processes are uncorrelated. Depending on the relative strength of the two processes, the gap may be deep or shallow,visible or invisible. Generally, the depth of the gap decreases with height...

On fitting the full spectrum of luminous red galaxies by using ULySS and STARLIGHT

International Nuclear Information System (INIS)

Liu Gao-Chao; Lu You-Jun; Chen Xue-Lei; Du Wei; Zhao Yong-Heng

2013-01-01

We select a sample of quiescent luminous red galaxies (LRGs) from the Sloan Digital Sky Survey Data Release 7 with a high signal-to-noise ratio (S/N) to study the consistency of fitting the full spectrum by using different packages, mainly, ULySS and STARLIGHT. The spectrum of each galaxy in the sample is fitted by the full spectrum fitting packages ULySS and STARLIGHT. We find: (1) for spectra with higher S/Ns, the ages of stellar populations obtained from ULySS are slightly older than those from STARLIGHT, and metallicities derived from ULySS are slightly richer than those from STARLIGHT. In general, both packages can give roughly consistent fitting results. (2) For low S/N spectra, it is possible that the fitting by ULySS can become trapped at some local minimum in the parameter space during execution and thus may give unreliable results, but STARLIGHT can still give reliable results. Based on the fitting results of LRGs, we further analyze their star formation history and the relation between their age and velocity dispersion, and find that they agree well with conclusions from previous works

Interference Management in Full-Duplex Cellular Networks with Partial Spectrum Overlap

KAUST Repository

Randrianantenaina, Itsikiantsoa

2017-03-31

Full-duplex (FD) communication is promoted to double the spectral efficiency when compared to the halfduplex (HD) counterpart. In the context of cellular networks, however, FD communication exacerbates the aggregate uplink and downlink interference, which diminishes the foreseen FD gains. This paper considers a flexible duplex system, denoted by -duplex (-D) system, wherein a fine-grained bandwidth control for each uplink/downlink channel pair in each base station (BS) is allowed, which also leads to partial spectrum overlap between the uplink and downlink channels. The paper addresses the resulting interference management problem by maximizing a network-wide rate-based utility function subject to uplink/downlink power constraints, so as to determine userto- BS association, user-to-channel scheduling, the UL and DL transmit powers, and the fraction of spectrum overlap between UL and DL for every user, under the assumption that the number of available channels and users are equal. The paper solves such a non-convex mixed-integer optimization problem in an iterative way by decoupling the problem into several subproblems. Particularly, the user-to-BS association problem is solved using a matching algorithm that is a generalization of the stable marriage problem. The scheduling problem is solved by iterative Hungarian algorithm. The power and spectrum overlap problem is solved by successive convex approximation. The proposed iterative strategy guarantees an efficient one-toone user to BS and channel assignment. It further provides optimized flexible duplexing and power allocation schemes for all transceivers. Simulations results show appreciable gains when comparing the proposed solution to different schemes from the literature.

Interference Management in Full-Duplex Cellular Networks with Partial Spectrum Overlap

KAUST Repository

Randrianantenaina, Itsikiantsoa; Dahrouj, Hayssam; Elsawy, Hesham; Alouini, Mohamed-Slim

2017-01-01

Full-duplex (FD) communication is promoted to double the spectral efficiency when compared to the halfduplex (HD) counterpart. In the context of cellular networks, however, FD communication exacerbates the aggregate uplink and downlink interference, which diminishes the foreseen FD gains. This paper considers a flexible duplex system, denoted by -duplex (-D) system, wherein a fine-grained bandwidth control for each uplink/downlink channel pair in each base station (BS) is allowed, which also leads to partial spectrum overlap between the uplink and downlink channels. The paper addresses the resulting interference management problem by maximizing a network-wide rate-based utility function subject to uplink/downlink power constraints, so as to determine userto- BS association, user-to-channel scheduling, the UL and DL transmit powers, and the fraction of spectrum overlap between UL and DL for every user, under the assumption that the number of available channels and users are equal. The paper solves such a non-convex mixed-integer optimization problem in an iterative way by decoupling the problem into several subproblems. Particularly, the user-to-BS association problem is solved using a matching algorithm that is a generalization of the stable marriage problem. The scheduling problem is solved by iterative Hungarian algorithm. The power and spectrum overlap problem is solved by successive convex approximation. The proposed iterative strategy guarantees an efficient one-toone user to BS and channel assignment. It further provides optimized flexible duplexing and power allocation schemes for all transceivers. Simulations results show appreciable gains when comparing the proposed solution to different schemes from the literature.

Full-profile fitting of emission spectrum to determine transition intensity parameters of Yb3+:GdTaO4

International Nuclear Information System (INIS)

Zhang Qingli; Sun Guihua; Ning Kaijie; Liu Wenpeng; Sun Dunlu; Yin Shaotang; Shi Chaoshu

2016-01-01

The Judd–Ofelt theoretic transition intensity parameters of luminescence of rare-earth ions in solids are important for the quantitative analysis of luminescence. It is very difficult to determine them with emission or absorption spectra for a long time. A “full profile fitting” method to obtain in solids with its emission spectrum is proposed, in which the contribution of a radiative transition to the emission spectrum is expressed as the product of transition probability, line profile function, instrument measurement constant and transition center frequency or wavelength, and the whole experimental emission spectrum is the sum of all transitions. In this way, the emission spectrum is expressed as a function with the independent variables intensity parameters , full width at half maximum (FWHM) of profile functions, instrument measurement constant, wavelength, and the Huang–Rhys factor S if the lattice vibronic peaks in the emission spectrum should be considered. The ratios of the experimental to the calculated energy lifetimes are incorporated into the fitting function to remove the arbitrariness during fitting and other parameters. Employing this method obviates measurement of the absolute emission spectrum intensity. It also eliminates dependence upon the number of emission transition peaks. Every experiment point in emission spectra, which usually have at least hundreds of data points, is the function with variables and other parameters, so it is usually viable to determine and other parameters using a large number of experimental values. We applied this method to determine twenty-five of Yb 3+ in GdTaO 4 . The calculated and experiment energy lifetimes, experimental and calculated emission spectrum are very consistent, indicating that it is viable to obtain the transition intensity parameters of rare-earth ions in solids by a full profile fitting to the ions’ emission spectrum. The calculated emission cross sections of Yb 3+ :GdTaO 4 also indicate

In-situ observation of Cu-Pt core-shell nanoparticles in the atomic scale by XAFS

International Nuclear Information System (INIS)

Zheng, Xusheng; Liu, Shoujie; Chen, Xing; Cheng, Jie; Ye, Qing; Pan, Zhiyun; Chu, Wangsheng; Wu, Ziyu; Marcelli, Augosto

2013-01-01

Bimetallic nanoparticles play an important role in potential industrial applications, such as catalysis, optoelectronics, information storage and biological labeling. Herein, homogeneous Cu-Pt core-shell nanoparticles with the averaged size of 8 nm have been synthesized by chemical methods. Cu atoms diffusion process, which motivated by heating, was observed in-situ by using temperature-dependent x-ray absorption fine-structure (XAFS) spectroscopy. Results show that Cu diffuse gradually from Cu core to Pt shell in these nanoparticles with increasing temperature. We also found the surface ligand (O) bonded Pt at the room temperature and were removed gradually by heating the sample. The analysis of the diffusion process in bimetallic nanoparticles will provide important guideline for their designing and tuning.

Speciation of As in calcite by micro-XAFS: Implications for remediation of As contamination in groundwater

International Nuclear Information System (INIS)

Yokoyama, Y; Takahashi, Y; Iwatsuki, T; Terada, Y

2013-01-01

To evaluate the role of calcite as a host phase of arsenic (As) in As-contaminated groundwater, distribution behavior of Asbetween natural calcite and groundwater in deep underground was investigated based on As oxidation state. Speciation analyses of As in natural calcite by μ-XRF-XAFS analyses showed (i) preferentialarsenate uptake by calcite, and (ii) promptness of arsenate uptake by minor iron (Fe) carbonate minerals coprecipitated with calcite. These findings suggest that the effect of calcite on As remediation of the As-contamination systems stronglydepends on arsenite to arsenate ratio (i.e., redox condition) in groundwater, and maybe governed bythe amount of Fe coprecipitated with calcite.

Climate Change, Instability and a Full Spectrum Approach to Conflict Prevention in Africa

Science.gov (United States)

2009-10-23

Climate change is an emerging threat to the national security of the United States. It has the potential to enhance the underlying causes of failed...around the globe. If climate change is the catalyst of crises to come, Africa Command (AFRICOM) must employ innovative and proactive cooperative theater...security plans and full spectrum stability operations to meet the challenges. This paper will first describe the threat posed by climate change and

Identification of different coordination geometries by XAFS in copper(II) complexes with trimesic acid

Science.gov (United States)

Gaur, A.; Klysubun, W.; Soni, Balram; Shrivastava, B. D.; Prasad, J.; Srivastava, K.

2016-10-01

X-ray absorption spectroscopy (XAS) is very useful in revealing the information about geometric and electronic structure of a transition-metal absorber and thus commonly used for determination of metal-ligand coordination. But XAFS analysis becomes difficult if differently coordinated metal centers are present in a system. In the present investigation, existence of distinct coordination geometries around metal centres have been studied by XAFS in a series of trimesic acid Cu(II) complexes. The complexes studied are: Cu3(tma)2(im)6 8H2O (1), Cu3(tma)2(mim)6 17H2O (2), Cu3(tma)2(tmen)3 8.5H2O (3), Cu3(tma) (pmd)3 6H2O (ClO4)3 (4) and Cu3(tma)2 3H2O (5). These complexes have not only Cu metal centres with different coordination but in complexes 1-3, there are multiple coordination geometries present around Cu centres. Using XANES spectra, different coordination geometries present in these complexes have been identified. The variation observed in the pre-edge features and edge features have been correlated with the distortion of the specific coordination environment around Cu centres in the complexes. XANES spectra have been calculated for the distinct metal centres present in the complexes by employing ab-initio calculations. These individual spectra have been used to resolve the spectral contribution of the Cu centres to the particular XANES features exhibited by the experimental spectra of the multinuclear complexes. Also, the variation in the 4p density of states have been calculated for the different Cu centres and then correlated with the features originated from corresponding coordination of Cu. Thus, these spectral features have been successfully utilized to detect the presence of the discrete metal centres in a system. The inferences about the coordination geometry have been supported by EXAFS analysis which has been used to determine the structural parameters for these complexes.

Are We Appropriately Developing Leaders to Fight and Lead in the Future Full Spectrum of Conflict?

National Research Council Canada - National Science Library

Pricone, Bob

2002-01-01

The thesis of this SRP is to examine whether we are appropriately training and developing our junior leaders to serve and lead in the future full spectrum environment and organizations, both Interim and Objective...

Full solar spectrum light driven thermocatalysis with extremely high efficiency on nanostructured Ce ion substituted OMS-2 catalyst for VOCs purification

Science.gov (United States)

Hou, Jingtao; Li, Yuanzhi; Mao, Mingyang; Yue, Yuanzheng; Greaves, G. Neville; Zhao, Xiujian

2015-01-01

The nanostructured Ce ion substituted cryptomelane-type octahedral molecular sieve (OMS-2) catalyst exhibits strong absorption in the entire solar spectrum region. The Ce ion substituted OMS-2 catalyst can efficiently transform the absorbed solar energy to thermal energy, resulting in a considerable increase of temperature. By combining the efficient photothermal conversion and thermocatalytic activity of the Ce ion substituted OMS-2 catalyst, we carried out full solar spectrum, visible-infrared, and infrared light driven catalysis with extremely high efficiency. Under the irradiation of full solar spectrum, visible-infrared, and infrared light, the Ce ion substituted OMS-2 catalyst exhibits extremely high catalytic activity and excellent durability for the oxidation of volatile organic pollutants such as benzene, toluene, and acetone. Based on the experimental evidence, we propose a novel mechanism of solar light driven thermocatalysis for the Ce ion substituted OMS-2 catalyst. The reason why the Ce ion substituted OMS-2 catalyst exhibits much higher catalytic activity than pure OMS-2 and CeO2/OMS-2 nano composite under the full solar spectrum irradiation is discussed.The nanostructured Ce ion substituted cryptomelane-type octahedral molecular sieve (OMS-2) catalyst exhibits strong absorption in the entire solar spectrum region. The Ce ion substituted OMS-2 catalyst can efficiently transform the absorbed solar energy to thermal energy, resulting in a considerable increase of temperature. By combining the efficient photothermal conversion and thermocatalytic activity of the Ce ion substituted OMS-2 catalyst, we carried out full solar spectrum, visible-infrared, and infrared light driven catalysis with extremely high efficiency. Under the irradiation of full solar spectrum, visible-infrared, and infrared light, the Ce ion substituted OMS-2 catalyst exhibits extremely high catalytic activity and excellent durability for the oxidation of volatile organic pollutants

CuS/RGO hybrid photocatalyst for full solar spectrum photoreduction from UV/Vis to near-infrared light.

Science.gov (United States)

Wu, Jie; Liu, Baibai; Ren, Zhenxing; Ni, Mengying; Li, Can; Gong, Yinyan; Qin, Wei; Huang, Yongli; Sun, Chang Q; Liu, Xinjuan

2018-05-01

To make full use of the solar energy, it remains a great challenge for semiconductor photocatalysts to harvest the full solar light spectrum from ultraviolet (UV) to visible even the near infrared (NIR) wavelength. Here we show firstly the CuS/RGO (reduced graphene oxide) hybrid photocatalyst synthesized via a microwave assisted method with full solar light (UV-Vis-NIR) active for efficient Cr(VI) reduction. The CuS/RGO displays high absorption and catalytic activity in the UV, visible and even the NIR light regions. As co-catalyst, RGO can separate and inhibit the recombination of charge carriers, consequently improving the catalytic activity. Only 1wt% RGO emersions can reduce 90% of Cr(VI) under the radiation of light over the full spectrum. Findings may provide a new strategy and substance to expand the utilization range of solar light from UV to visible even the NIR energy. Copyright © 2017. Published by Elsevier Inc.

Confocal μ-XRF, μ-XAFS, and μ-XRD Studies of Sediment from a Nuclear Waste Disposal Natural Analogue Site and Fractured Granite Following a Radiotracer Migration Experiment

International Nuclear Information System (INIS)

Denecke, Melissa A.; Brendebach, Boris; Rothe, Joerg; Simon, Rolf; Janssens, Koen; Nolf, Wout de; Vekemans, Bart; Falkenberg, Gerald; Somogyi, Andrea; Noseck, Ulrich

2007-01-01

Combined μ-XRF, μ-XAFS, and μ-XRD investigations of a uranium-rich tertiary sediment, from a nuclear repository natural analogue site, and a fractured granite bore core section after a column tracer experiment using a Np(V) containing cocktail have been performed. Most μ-XRF/μ-XAFS measurements are recorded in a confocal geometry to provide added depth information. The U-rich sediment results show uranium to be present as a tetravalent phosphate and that U(IV) is associated with As(V). Arsenic present is either As(V) or As(0). The As(0) forms thin coatings on the surface of pyrite nodules. A hypothesis for the mechanism of uranium immobilization is proposed, where arsenopyrite acted as reductant of ground water dissolved U(VI) leading to precipitation of less soluble U(IV) and thereby forming As(V). Results for the granite sample show the immobilized Np to be tetravalent and associated with facture material

Gamma-ray Full Spectrum Analysis for Environmental Radioactivity by HPGe Detector

Science.gov (United States)

Jeong, Meeyoung; Lee, Kyeong Beom; Kim, Kyeong Ja; Lee, Min-Kie; Han, Ju-Bong

2014-12-01

Odyssey, one of the NASA¡¯s Mars exploration program and SELENE (Kaguya), a Japanese lunar orbiting spacecraft have a payload of Gamma-Ray Spectrometer (GRS) for analyzing radioactive chemical elements of the atmosphere and the surface. In these days, gamma-ray spectroscopy with a High-Purity Germanium (HPGe) detector has been widely used for the activity measurements of natural radionuclides contained in the soil of the Earth. The energy spectra obtained by the HPGe detectors have been generally analyzed by means of the Window Analysis (WA) method. In this method, activity concentrations are determined by using the net counts of energy window around individual peaks. Meanwhile, an alternative method, the so-called Full Spectrum Analysis (FSA) method uses count numbers not only from full-absorption peaks but from the contributions of Compton scattering due to gamma-rays. Consequently, while it takes a substantial time to obtain a statistically significant result in the WA method, the FSA method requires a much shorter time to reach the same level of the statistical significance. This study shows the validation results of FSA method. We have compared the concentration of radioactivity of 40K, 232Th and 238U in the soil measured by the WA method and the FSA method, respectively. The gamma-ray spectrum of reference materials (RGU and RGTh, KCl) and soil samples were measured by the 120% HPGe detector with cosmic muon veto detector. According to the comparison result of activity concentrations between the FSA and the WA, we could conclude that FSA method is validated against the WA method. This study implies that the FSA method can be used in a harsh measurement environment, such as the gamma-ray measurement in the Moon, in which the level of statistical significance is usually required in a much shorter data acquisition time than the WA method.

Underlay Spectrum Sharing Techniques with In-Band Full-Duplex Systems using Improper Gaussian Signaling

KAUST Repository

Gaafar, Mohamed

2016-10-26

Sharing the spectrum with in-band full-duplex (FD) primary users (PUs) is a challenging and interesting problem in the underlay cognitive radio (CR) systems. The self-interference introduced at the primary network may dramatically impede the secondary user (SU) opportunity to access the spectrum. To tackle this problem, we use the so-called improper Gaussian signaling. Particularly, we assume the downlink transmission of a SU that uses improper Gaussian signaling while the FD PU pair implements the regular proper Gaussian signaling. First, we derive a closed form expression and an upper bound for the SU and PUs outage probabilities, respectively. Second, we optimize the SU signal parameters to minimize its outage probability while maintaining the required PUs quality-of-service based on the average channel state information (CSI). Moreover, we provide the conditions to reap merits from employing improper Gaussian signaling at the SU. Third, we design the SU signal parameters based on perfect knowledge of its direct link instantaneous CSI and investigate all benefits that can be achieved at both the SU and PUs. Finally, we provide some numerical results that demonstrate the advantages of using improper Gaussian signaling to access the spectrum of the FD PUs.

The Xenon Test Chamber Q-SUN® for testing realistic tolerances of fungi exposed to simulated full spectrum solar radiation.

Science.gov (United States)

Dias, Luciana P; Araújo, Claudinéia A S; Pupin, Breno; Ferreira, Paulo C; Braga, Gilberto Ú L; Rangel, Drauzio E N

2018-06-01

The low survival of insect-pathogenic fungi when used for insect control in agriculture is mainly due to the deleterious effects of ultraviolet radiation and heat from solar irradiation. In this study, conidia of 15 species of entomopathogenic fungi were exposed to simulated full-spectrum solar radiation emitted by a Xenon Test Chamber Q-SUN XE-3-HC 340S (Q-LAB ® Corporation, Westlake, OH, USA), which very closely simulates full-spectrum solar radiation. A dendrogram obtained from cluster analyses, based on lethal time 50 % and 90 % calculated by Probit analyses, separated the fungi into three clusters: cluster 3 contains species with highest tolerance to simulated full-spectrum solar radiation, included Metarhizium acridum, Cladosporium herbarum, and Trichothecium roseum with LT 50  > 200 min irradiation. Cluster 2 contains eight species with moderate UV tolerance: Aschersonia aleyrodis, Isaria fumosorosea, Mariannaea pruinosa, Metarhizium anisopliae, Metarhizium brunneum, Metarhizium robertsii, Simplicillium lanosoniveum, and Torrubiella homopterorum with LT 50 between 120 and 150 min irradiation. The four species in cluster 1 had the lowest UV tolerance: Lecanicillium aphanocladii, Beauveria bassiana, Tolypocladium cylindrosporum, and Tolypocladium inflatum with LT 50  solar radiation before. We conclude that the equipment provided an excellent tool for testing realistic tolerances of fungi to full-spectrum solar radiation of microbial agents for insect biological control in agriculture. Copyright © 2018 British Mycological Society. Published by Elsevier Ltd. All rights reserved.

XAFS study of GeO sub 2 glass under pressure

CERN Document Server

Ohtaka, O; Fukui, H; Murai, K; Okube, M; Takebe, H; Katayama, Y; Utsumi, W

2002-01-01

Using a large-volume high-pressure apparatus, Li sub 2 O-4GeO sub 2 glass and pure GeO sub 2 gel have been compressed to 14 GPa at room temperature and their local structural changes have been investigated by an in situ XAFS (x-ray absorption fine-structure) method. On compression of Li sub 2 O-4GeO sub 2 glass, the Ge-O distance gradually becomes short below 7 GPa, showing the conventional compression of the GeO sub 4 tetrahedron. Abrupt increase in the Ge-O distance occurs between 8 and 10 GPa, which corresponds to the coordination number (CN) changing from 4 to 6. The CN change is completed at 10 GPa. On decompression, the reverse transition occurs gradually below 10 GPa. In contrast to the case for Li sub 2 O-4GeO sub 2 glass, the Ge-O distance in GeO sub 2 gel gradually increases over a pressure range from 2 to 12 GPa, indicating that continuous change in CN occurs. The Ge-O distance at 12 GPa is shorter than that of Li-4GeO sub 2 indicating that the change in CN is not completed even at this pressure. O...

Speciation of uranium in minerals by Sem, Tem, μ-PIXE, XPS and XAFS

International Nuclear Information System (INIS)

Toshihiko Ohnuki; Hiroshi Isobe; Tomihiro Kamiya; Takuro Sakai; Takashi Murakami

2001-01-01

Many kinds of electromagnetic waves and particle beams are used as analytical probes for the investigation of uranium-mineralogy and speciation. The representatives of the probes are SEM, TEM, μ-PIRE, XPS and XAFS. Each of these analytical probes has its own advantages and disadvantages. We have performed studies to compare the advantages and disadvantages on the basis of the analysis of the distribution and speciation of U containing rock samples collected at the Koongarra uranium deposit, Australia. The spatial resolutions of the probes are in the order of TEM>SEM, μ-PIXE>XFAS, XPS. The lower detection limits of the probes are in the order of μ-PIXE< TEM, SEM< XFAS, XPS. Oxidation state of U was determined by XFAS and XPS. These results indicate that combination of the above probes can give us sufficient data on U speciation not only in natural rock samples but in solid samples obtained in the laboratory. (authors)

Embracing a Full Spectrum Definition of Art Therapy

Science.gov (United States)

Spooner, Heather

2016-01-01

In this viewpoint the author makes a case for developing a clear and concise definition of art therapy that can easily be adopted by art therapists working across a spectrum of theoretical frameworks. The reader is asked to widen the lens through which art therapy is defined by considering its influence on society, the mind, health, and behavior.…

Xafs studies on actinide-pyridine-diamide complexes for development of an innovative separation process

International Nuclear Information System (INIS)

Hideaki, Shiwaku; Tsuyoshi, Yaita; Tohru, Kobayashi; Masahiko, Numakura; Tsuyoshi, Yaita; Shinichi, Suzuki; Yoshihiro, Okamoto

2007-01-01

We have been studying the bond properties and the structures of actinide (An) and lanthanide (Ln) complexes in detail using several kinds of X-ray analyses by synchrotron radiation in order to elucidate the ionic recognition mechanism of organic ligands. Generally, an oxygen donor type ligand separates both An and Ln from solutions of spent fuel or high level radioactive waste. Separation ability of this type of ligand for An and Ln follows the order of the surface charge density of an ion, i.e., An 4+ > AnO 2 2+ > An 3+ = Ln 3+ > AnO 2+ and/or a few structural factors. Therefore, this type of ligand is ineffective for the separation of An 3+ and Ln 3+ due to their similar chemical properties. Recently, new extractants like aromatic N-donor ligands have been developed using the preference of soft-donors to achieve the An 3+ /Ln 3+ separation. However, aromatic N-donor ligands often show a few problems such as protonation. In this developing process, we synthesized a new type of ligand, N,N'-dimethyl-N,N'-diphenyl-pyridine-2,6-carboxy-amide (DMDPh-PDA). The PDA is hybrid type ligand having oxygen and nitrogen as donor atoms and follows a unique separation order, i.e., An 4+ > An 3+ > AnO 2 2+ > Ln 3+ > AnO 2 + , probably arising from the combined effects of covalent bonding and steric hindrance. Hence, clarification of any ionic recognition mechanism of the PDA is very interesting from the view point of structural analysis. In this presentation, we will show XAFS results of An and Ln complexes with PDA in solution and discuss separation mechanism of An and Ln by PDA. Various kinds of complexes between Ln/An and PDA were prepared for XAFS analysis. The Ln complexes were measured in transmission mode at the K absorption edge on the BL11XU at SPring-8. On the other hand, the U complexes were measured in fluorescence mode at the L III absorption edge on the BL-27B at Photon Factory, High-energy Accelerator Research Organization (KEK). (authors)

Structural Investigation of Fe-Ni-S and Fe-Ni-Si Melts by High-temperature Fluorescence XAFS Measurements

International Nuclear Information System (INIS)

Manghnani, Murli H.; Balogh, John; Hong Xinguo; Newville, Matthew; Amulele, G.

2007-01-01

Iron-nickel (Fe-Ni) alloy is regarded as the most abundant constituent of Earth's core, with an amount of 5.5 wt% Ni in the core based on geochemical and cosmochemical models. The structural role of nickel in liquid Fe-Ni alloys with light elements such as S or Si is poorly understood, largely because of the experimental difficulties of high-temperature melts. Recently, we have succeeded in acquiring Ni K-edge fluorescence x-ray absorption fine structure (XAFS) spectra of Fe-Ni-S and Fe-Ni-Si melts and alloys. Different structural environment of Ni atoms in Fe-Ni-S and Fe-Ni-Si melts is observed, supporting the effect of light elements in Fe-Ni melts

The theoretical study of full spectrum analysis method for airborne gamma-ray spectrometric data

International Nuclear Information System (INIS)

Ni Weichong

2011-01-01

Spectra of airborne gamma-ray spectrometry was found to be the synthesis of spectral components of radioelement sources by analyzing the constitution of radioactive sources for airborne gamma-ray spectrometric survey and establishing the models of gamma-ray measurement. The mathematical equation for analysising airborne gamma-ray full spectrometric data can be expressed into matrix and related expansions were developed for the mineral resources exploration, environmental radiation measurement, nuclear emergency monitoring, and so on. Theoretical study showed that the atmospheric radon could be directly computed by airborne gamma-ray spectrometric data with full spectrum analysis without the use of the accessional upward-looking detectors. (authors)

VRF ("Visual RobFit") — nuclear spectral analysis with non-linear full-spectrum nuclide shape fitting

Science.gov (United States)

Lasche, George; Coldwell, Robert; Metzger, Robert

2017-09-01

A new application (known as "VRF", or "Visual RobFit") for analysis of high-resolution gamma-ray spectra has been developed using non-linear fitting techniques to fit full-spectrum nuclide shapes. In contrast to conventional methods based on the results of an initial peak-search, the VRF analysis method forms, at each of many automated iterations, a spectrum-wide shape for each nuclide and, also at each iteration, it adjusts the activities of each nuclide, as well as user-enabled parameters of energy calibration, attenuation by up to three intervening or self-absorbing materials, peak width as a function of energy, full-energy peak efficiency, and coincidence summing until no better fit to the data can be obtained. This approach, which employs a new and significantly advanced underlying fitting engine especially adapted to nuclear spectra, allows identification of minor peaks that are masked by larger, overlapping peaks that would not otherwise be possible. The application and method are briefly described and two examples are presented.

Full Solar Spectrum Light Driven Thermocatalysis with Extremely High Efficiency on Nanostructured Ce Ion Substituted OMS-2 Catalyst for VOCs Purification

DEFF Research Database (Denmark)

Hou, J.T.; Li, Y.Z.; Mao, M.Y.

2015-01-01

solar spectrum, visible-infrared, and infrared light, the Ce ion substituted OMS-2 catalyst exhibits extremely high catalytic activity and excellent durability for the oxidation of volatile organic pollutants such as benzene, toluene, and acetone. Based on the experimental evidence, we propose a novel...... in a considerable increase of temperature. By combining the efficient photothermal conversion and thermocatalytic activity of the Ce ion substituted OMS-2 catalyst, we carried out full solar spectrum, visible-infrared, and infrared light driven catalysis with extremely high efficiency. Under the irradiation of full...... mechanism of solar light driven thermocatalysis for the Ce ion substituted OMS-2 catalyst. The reason why the Ce ion substituted OMS-2 catalyst exhibits much higher catalytic activity than pure OMS-2 and CeO2/OMS-2 nano composite under the full solar spectrum irradiation is discussed....

Calcium in ancient glazes and glasses: a XAFS study

Energy Technology Data Exchange (ETDEWEB)

Veiga, J.P. [New University of Lisbon, CENIMAT, Materials Science Dept., Caparica (Portugal); Figueiredo, M.O. [New University of Lisbon, CENIMAT, Materials Science Dept., Caparica (Portugal); Crystallography and Mineralogy Centre, IICT, and INETI/IGM, Dept. Min. Resources, Alfragide (Portugal)

2008-07-15

Ceramic tiles used to manufacture artistic panels during the XVI to the XVIII centuries were decorated with high-lead soda-lime glazes, incorporating a diversity of chromophore cations, as ascertained by SRXRF (synchrotron radiation X-ray fluorescence). Previous X-ray absorption spectroscopy (XAS) studies have shown that sodium and lead are hosted by the glassy matrix in those glazes. However, the possible role of calcium as a modifier of the tetrahedral silica network is not fully clarified, despite being recognized that calcium cations alter some fundamental properties of glazes, namely transparency. An X-ray absorption fine structure (XAFS) study of glazes with varied colorings was therefore undertaken at Ca K- and L-edges. Well crystallized oxide minerals were used to model distinct coordination environments by oxygen atoms - close to octahedral geometry in calcite and dodecahedral in gypsum - while fluorite was chosen to mimic ideal cubic coordination. A first XAS approach suggested a minor variation in the energy separation between L{sub 2}-L{sub 3} absorption edges when comparing blue and yellow glazes, irrespective of the period of manufacture. A further study on the X-ray absorption near-edge structure (XANES) carried out at the K-edge corroborated this difference and, along with the theoretical spectra modeling performed with the FEFF code, allowed interpreting of the Ca 1s absorption spectra of glazes as arising from a non-regular high-coordination environment within the silica matrix. (orig.)

Spatially resolved XRF, XAFS, XRD, STXM and IR investigation of a natural U-rich clay

Science.gov (United States)

Denecke, M. A.; Michel, P.; Schäfer, T.; Huber, F.; Rickers, K.; Rothe, J.; Dardenne, K.; Brendebach, B.; Vitova, T.; Elie, M.

2009-11-01

Combined spatially resolved hard X-ray μ-XRF and μ-XAFS studies using an X-ray beam with micrometer dimensions at the INE-Beamline for actinide research at ANKA and Beamline L at HASYLAB with those from scanning transmission soft X-ray microscopy (STXM) and synchrotron-based Fourier transform infrared microspectroscopy (μ-FTIR) recorded with beam spots in the nanometer range are used to study a U-rich clay originating from Autunian shales in the Permian Lodève Basin (France). This argillaceous formation is a natural U deposit associated with organic matter (bitumen). Results allow us to differentiate between possible mechanisms leading to U enrichment: likely U immobilization via reaction with organic material associated with clay mineral. Such investigations support development of reliable assessment of the long term radiological safety for proposed nuclear waste disposal sites.

Wet-chemical synthesis of nanoscale iron boride, XAFS analysis and crystallisation to α-FeB.

Science.gov (United States)

Rades, Steffi; Kornowski, Andreas; Weller, Horst; Albert, Barbara

2011-06-20

The reaction of lithium tetrahydridoborate and iron bromide in high boiling ether as reaction medium produces an ultrafine, pyrophoric and magnetic precipitate. X-ray and electron diffraction proved the product to be amorphous. According to X-ray absorption fine structure spectroscopy (XAFS) the precipitate has FeB structure up to nearly two coordination spheres around an iron absorber atom. Transmission electron microscopy (TEM) confirms the ultrafine powder to be nanoscale. Subsequent annealing at 450 °C causes the atoms to arrange in a more distinct FeB structure, and further thermal treatment to 1050 °C extends the local structure to the α-modification of FeB. Between 1050 °C and 1500 °C α-FeB is transformed into β-FeB. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Rediscovering Red: Full-Spectrum Structural Color in Colloidal Glasses

Science.gov (United States)

Magkiriadou, Sofia; Park, Jin-Gyu; Kim, Young-Seok; Yi, Gi-Ra; Manoharan, Vinothan N.

2014-03-01

We use colloidal glasses to develop pigments with structural color: color that arises from interference rather than absorption. This pigmentation mechanism is common in blue birds, whose feather barbs often contain glassy microstructures. When a glass is illuminated, the spatial correlations between neighboring particles can give rise to constructive interference for a small range of wavelengths. Unlike the colors arising from Bragg diffraction in crystals, the colors of these ``photonic glasses'' are independent of angle due to the disordered, isotropic structure. However, there are no known examples of photonic glasses with pure structural red color, either in nature or in the lab. We present both experimental evidence and a model showing that the absence of red is due to the wavelength-dependence of the single-particle scattering cross-section. We show that this problem can be solved in ``inverse glasses,'' namely glasses composed of particles with refractive index lower than that of their medium. Although these systems are similar to those in birds, no known species uses this mechanism to create red. We use inverse glasses to make full-spectrum, angle-independent structural colors. This will enable the use of colloidal glasses as a new type of long-lasting, non-bleaching pigment.

The full spectrum of ethical issues in the care of patients with ALS: a systematic qualitative review.

Science.gov (United States)

Seitzer, F; Kahrass, H; Neitzke, G; Strech, D

2016-02-01

Dealing systematically with ethical issues in amyotrophic lateral sclerosis (ALS) care requires an unbiased awareness of all the relevant ethical issues. The aim of the study was to determine systematically and transparently the full spectrum of ethical issues in ALS care. We conducted a systematic review in Medline and Google Books (restricted to English and German literature published between 1993 and 2014). We applied qualitative text analysis and normative analysis to categorise the spectrum of ethical issues in ALS care. The literature review retrieved 56 references that together mentioned a spectrum of 103 ethical issues in ALS care. The spectrum was structured into six major categories that consist of first and second-order categories of ethical issues. The systematically derived spectrum of ethical issues in ALS care presented in this paper raises awareness and understanding of the complexity of ethical issues in ALS care. It also offers a basis for the systematic development of informational and training materials for health professionals, patients and their relatives, and society as a whole. Finally, it supports a rational and fair selection of all those ethical issues that should be addressed in health policies, position papers and clinical practice guidelines. Further research is needed to identify ways to systematically select the most relevant ethical issues not only in the clinical environment, but also for the development of clinical practice guidelines.

XAFS Study of Epitaxial CoxTi1-xO2-x Anatase

International Nuclear Information System (INIS)

Heald, S.M.; Chambers, S.A.; Droubay, T.

2009-01-01

Co doped TiO 2 -anatase is a promising candidate for a room-temperature ferromagnetic semiconductor. XAFS measurements have been used to investigate the local Co environment and Co valence for several Co-anatase films. The samples were grown on LaAlO 3 (001) by oxygen plasma assisted molecular beam epitaxy and on SrTiO 3 by atomic oxygen assisted MBE. Co concentrations were about 5%. The measurements were made at the PNC-CAT bending magnet and undulator beamlines at the Advanced Photon Source. For the films on LaAlO 3 , the near edge clearly shows the presence of only Co(2+), and no evidence for metallic Co, while the films on SrTiO 3 showed significant metallic Co. Analysis of the extended fine structure for the LaAlO 3 films finds that the Co substitutes for Ti with some distortion of the lattice. Both in-plane and out-of-plane Co-O bonds are expanded from the Ti-O bonds in anatase. The in-plane bonds are expanded approximately twice as much. A deficit in the oxygen coordination number suggests a correlation of oxygen vacancies with Co sites.

Assessment of Zn bioavailability: XAFS study on speciation of zinc-particulate organic matter associations in polluted soils

Energy Technology Data Exchange (ETDEWEB)

Harfouche, M; Borca, C; Grolimund, D [Swiss Light Source, Institut Paul Scherrer, Villigen (Switzerland); Labanowski, J [UMR CNRS 6008, Laboratoire de Chimie et Microbiologie de l' Eau, Universite de Poitiers (France); Farges, F [USM 201 and CNRS UMR 7202, Museum National d' Histoire Naturelle, Paris (France); Hullebusch, E van [Laboratoire Geomateriaux et Environnement, Universite de Paris-Est (France); Oort, F van, E-mail: messaoud.harfouche@psi.c, E-mail: vanoort@versailles.inra.f [UR INRA 251, Physico-chimie et Ecotoxicologie des Sols d Agrosystemes Contamines, Versailles (France)

2009-11-15

We present a study about the behavior of Zn in agricultural soils polluted 100-50 years ago by metallurgical fallout and used nowadays for corn production. Such type of soil concerns an area of several km{sup 2} around former metallurgical complex in Northern France. Despite the moderated metal amounts of these soils, the metals deposited over the agricultural area still indirectly expose nowadays populations through the food chain. In contrast to the most contaminated industrial site, these more distant agricultural areas have been less studied. The study was focused on Zn, a relative mobile metal element, since its predominant occurrence in the surface horizon of sandy textured soils, fifty years after cessation of metallurgical activity suggests its immobilization due to specific soil mechanisms. To evaluate how Zn is associated to POM, Zn K-edge XAFS spectra were collected at 293 K at the SLS on beamlines superXAS and microXAS, using Si(111) monochromators and solid state Ge detectors. Energetic resolution is ca. 2 eV at 9 KeV. Lateral resolution varied from ca. 1 mm{sup 2} to 15 micron{sup 2}. Spectra were normalized with the XAFS 3.0 software. We studied different POM size fractions isolated from soils. The largest POM particles correspond to recent leaves or roots fragments. The finest POM particles correspond to decomposition by-products. The results revealed a multiple and heterogeneous speciation of Zn with POM. We observed that little interactions from next-nearest neighbors around Zn. We concluded that most of the Zn tends to be located in the POM matrix as a Zn-organic speciation. We also collected macroscopic EXAFS data on selected intact POM particles probed at the micron scale. The results show that the remaining Zn-distribution related to inorganic (hot-spots), possibly franklinite-type, is minor compared to the Zn-organic speciation. Such observations will help to better understand the mechanisms that regulate the bioavailability and

A simple dental caries detection system using full spectrum of laser-induced fluorescence

Science.gov (United States)

Rocha-Cabral, Renata Maciel; Mendes, Fausto Medeiros; Maldonado, Edison Puig; Zezell, Denise Maria

2015-06-01

Objectives: to develop an apparatus for the detection of early caries lesions in enamel using the full extent of the tooth fluorescence spectrum, through the integration of a laser diode, fiber optics, filters and one portable spectrometer connected to a computer, all commercially available; to evaluate the developed device in clinical and laboratory tests, and compare its performance with commercial equipment. Methods: clinical examinations were performed in patients with indication for exodontics of premolars. After examinations, the patients underwent surgery and the teeth were stored individually. The optical measurements were repeated approximately two months after extraction, on the same sites previously examined, then histological analysis was carried out. Results: the spectral detector has presented high specificity and moderate sensitivity when applied to differentiate between healthy and damaged tissues, with no significant differences from the performance of the commercial equipment. The developed device is able to detect initial damages in enamel, with depth of approximately 300 μm. Conclusions: we successfully demonstrated the development of a simple and portable system based in laser-induced fluorescence for caries detection, assembled from common commercial parts. As the spectral detector acquires a complete recording of the spectrum from each tissue, it is possible to use it for monitoring developments of caries lesions.

Proximal gamma-ray spectroscopy to predict soil properties using windows and full-spectrum analysis methods.

Science.gov (United States)

Mahmood, Hafiz Sultan; Hoogmoed, Willem B; van Henten, Eldert J

2013-11-27

Fine-scale spatial information on soil properties is needed to successfully implement precision agriculture. Proximal gamma-ray spectroscopy has recently emerged as a promising tool to collect fine-scale soil information. The objective of this study was to evaluate a proximal gamma-ray spectrometer to predict several soil properties using energy-windows and full-spectrum analysis methods in two differently managed sandy loam fields: conventional and organic. In the conventional field, both methods predicted clay, pH and total nitrogen with a good accuracy (R2 ≥ 0.56) in the top 0-15 cm soil depth, whereas in the organic field, only clay content was predicted with such accuracy. The highest prediction accuracy was found for total nitrogen (R2 = 0.75) in the conventional field in the energy-windows method. Predictions were better in the top 0-15 cm soil depths than in the 15-30 cm soil depths for individual and combined fields. This implies that gamma-ray spectroscopy can generally benefit soil characterisation for annual crops where the condition of the seedbed is important. Small differences in soil structure (conventional vs. organic) cannot be determined. As for the methodology, we conclude that the energy-windows method can establish relations between radionuclide data and soil properties as accurate as the full-spectrum analysis method.

Portfolio and diversity analysis of energy technologies using full-spectrum risk measures

Energy Technology Data Exchange (ETDEWEB)

Jansen, J.C.; Beurskens, L.W.M. [ECN Policy Studies, Petten (Netherlands); Awerbuch, S.; Stirling, A.C. [Science and Technology Policy Research SPRU, University of Sussex, Brighton, East Sussex (United Kingdom)

2005-01-01

Energy diversity and security have been evaluated using the multi-criteria diversity analysis (MDA) of A. C. Stirling as well as more classical Markowitz mean-variance portfolio (MVP) theory. Each of these approaches is capable of producing an efficient frontier that shows optimal generating portfolio mixes, those that maximize performance (i.e. minimize cost) while minimizing risk or uncertainty (i.e. maximizing diversity). MDA covers the full-spectrum of uncertainty, reaching into areas where little is known about the range of possible outcomes, let alone their probabilities. However, MDA does not exploit statistical information that is available in certain parts of the risk-spectrum where historic means, variances and co-variances of outcomes are known and can be used to make inferences about the future. MVP operates precisely in this space. However, like other capital market models, its prescriptive value rests on the idea that the past is the best guide to the future. As such MVP can be blind to unforeseen events that create future structural change. Used in isolation, therefore, neither model offers a fully satisfying result. An MVP analysis of energy technologies tells us how to create generating portfolios with minimum cost and risk (cost-variance), assuming historic ranges predict the future well enough. If policy makers are confident that past expected values, ranges and variances will continue, then the solutions are fine. But what about so-called unknown risks? Possible future events that may produce outcomes with unknown consequences? This is where MDA becomes a potentially powerful tool. This project seeks to merge the two approaches and to map the space between optimal MVP and MDA solutions using a combined MVP+MDA optimization and weighting scheme. Placing 100% of the emphasis on MVP, for example, produces results based purely on historical trends. These may serve for short planning horizons. On the other hand, giving MDA a 100% weighting produces

Light hadron spectrum in 2+1 flavor full QCD by CP-PACS and JLQCD Collaborations

International Nuclear Information System (INIS)

Ishikawa, T.; Aoki, S.; Fukugita, M.; Hashimoto, S.; Ishikawa, K-I.; Ishizuka, N.; Iwasaki, Y.; Kanaya, K.; Kaneko, T.; Kuramashi, Y.; Okawa, M.; Onogi, T.; Taniguchi, N.; Tsutsui, N.; Ukawa, A.; Yoshie, T.

2005-01-01

CP-PACS and JLQCD Collaborations are carrying out a joint project of the 2+1 flavor full QCD with the RG-improved gauge action and the non-perturbatively O(a)-improved Wilson quark action. This simulation removes quenching effects of all three light quarks, which is the last major uncertainty in lattice QCD. In this report we present our results for the light meson spectrum and quark masses on a 20 3 x40 lattice at the lattice spacing a∼0.10 fm

Full dimensional (15-dimensional) quantum-dynamical simulation of the protonated water dimer. II. Infrared spectrum and vibrational dynamics

DEFF Research Database (Denmark)

Vendrell, Oriol; Gatti, Fabien; Meyer, Hans-Dieter

2007-01-01

The infrared absorption spectrum of the protonated water dimer (H5O2+) is simulated in full dimensionality (15 dimensional) in the spectral range of 0-4000 cm(-1). The calculations are performed using the multiconfiguration time-dependent Hartree (MCTDH) method for propagation of wavepackets. All...

X-ray created metamaterials: applications to metal-free structural colors with full chromaticity spectrum and 80 nm spatial resolution

KAUST Repository

Bonifazi, Marcella

2018-05-07

We created new types of metamaterials by hard X-rays possessing high fluency. We discuss applications in structural colors that show full spectrum of Cyan, Yellow, Magenta, Black (CYMK), realized in transparent dielectrics with 80 nm resolution.

X-ray created metamaterials: applications to metal-free structural colors with full chromaticity spectrum and 80 nm spatial resolution

KAUST Repository

Bonifazi, Marcella; Mazzone, Valerio; Fratalocchi, Andrea

2018-01-01

We created new types of metamaterials by hard X-rays possessing high fluency. We discuss applications in structural colors that show full spectrum of Cyan, Yellow, Magenta, Black (CYMK), realized in transparent dielectrics with 80 nm resolution.

X-ray-absorption fine structure determination of pressure-induced bond-angle changes in ReO3

International Nuclear Information System (INIS)

Houser, B.; Ingalls, R.

2000-01-01

We report here on a Marquardt-type method to fit the x-ray absorption fine structure (XAFS) of ReO 3 . We find that, when the ambient-pressure structure of ReO 3 is used as a starting point, the pressure dependence of the angle of the Re-O-Re bond in ReO 3 is fairly straightforwardly and robustly determined using FEFF curved-wave, multiple-scattering programs and is accurate to about ±1.5 degree sign or better. We present an argument that XAFS and scattering experiments fundamentally differ in what they measure in the case of nearly linear atomic bridges. Focussed multiple-scattering paths involving the Re-O-Re bridge make a contribution to the XAFS spectrum that is sensitive to the rms deviation of oxygen from the [100]-type directions. Fits to simulated spectra back up our contention that for XAFS experiments the effective position of the oxygen atom is its rms displacement whether the average displacement is zero or not. (c) 2000 The American Physical Society

Design and Analysis of Hybrid Solar Lighting and Full-Spectrum Solar Energy Systems

International Nuclear Information System (INIS)

Muhs, J.D.

2001-01-01

This paper describes a systems-level design and analysis of a new approach for improving the energy efficiency and affordability of solar energy in buildings, namely, hybrid solar lighting and full-spectrum solar energy systems. By using different portions of the solar spectrum simultaneously for multiple end-use applications in buildings, the proposed system offers unique advantages over other alternatives for using sunlight to displace electricity (conventional topside daylighting and solar technologies). Our preliminary work indicates that hybrid solar lighting, a method of collecting and distributing direct sunlight for lighting purposes, will alleviate many of the problems with passive daylighting systems of today, such as spatial and temporal variability, glare, excess illumination, cost, and energy efficiency. Similarly, our work suggests that the most appropriate use of the visible portion of direct, nondiffuse sunlight from an energy-savings perspective is to displace electric light rather than generate electricity. Early estimates detailed in this paper suggest an anticipated system cost of well under$2.0/Wp and 5-11(cents)/kWh for displaced and generated electricity in single-story commercial building applications. Based on a number of factors discussed in the paper, including sunlight availability, building use scenarios, time-of-day electric utility rates, cost, and efficacy of the displaced electric lights, the simple payback of this approach in many applications could eventually be well under 5 years

Energy-modulation spectroscopy in hard X-ray region

CERN Document Server

Suzuki, M; Ishikawa, T

2001-01-01

An energy-modulation technique has been developed for XAFS spectroscopies requiring high energy resolution and high precision. Fast energy switching at 40 Hz has been achieved by adopting a Si channel-cut crystal as a second monochromator together with a piezo-driven oscillation stage, and the resulting variation in sample absorption was detected using an amplifier locked to the energy-modulation frequency. An energy-derivative XAFS spectrum was directly obtained at the Mn K-edge, and illustrated the advantages of this technique in high energy resolution and noise reduction.

Metal free structural colours via disordered nanostructures with nm resolution and full CYMK colour spectrum

KAUST Repository

Bonifazi, Marcella

2017-02-28

Structural colours represents a research area of great interest, due to a wide field of application ranging from micro-security to biomimetic materials. At present metallic substrate are heavily employed and only a partial spectra of colours can be realised. We propose a novel, metal-free technology that exploits the complex scattering from a disordered three-dimensional dielectric material on a silicon substrate. We reproduce experimentally the full spectrum of CMYK colours, including variations in intensity. Our resolution lies in the nm range, limited only by the electron beam lithography fabrication process. We demonstrate that this technique is extremely robust, suitable for flexible and reusable substrates. Full of these notable proprieties these nano-structures fits perfectly with the requirements of a real-world technology.

Metal free structural colours via disordered nanostructures with nm resolution and full CYMK colour spectrum

KAUST Repository

Bonifazi, Marcella; Mazzone, Valerio; Fratalocchi, Andrea

2017-01-01

Structural colours represents a research area of great interest, due to a wide field of application ranging from micro-security to biomimetic materials. At present metallic substrate are heavily employed and only a partial spectra of colours can be realised. We propose a novel, metal-free technology that exploits the complex scattering from a disordered three-dimensional dielectric material on a silicon substrate. We reproduce experimentally the full spectrum of CMYK colours, including variations in intensity. Our resolution lies in the nm range, limited only by the electron beam lithography fabrication process. We demonstrate that this technique is extremely robust, suitable for flexible and reusable substrates. Full of these notable proprieties these nano-structures fits perfectly with the requirements of a real-world technology.

A full-spectrum analysis of high-speed train interior noise under multi-physical-field coupling excitations

Science.gov (United States)

Zheng, Xu; Hao, Zhiyong; Wang, Xu; Mao, Jie

2016-06-01

High-speed-railway-train interior noise at low, medium, and high frequencies could be simulated by finite element analysis (FEA) or boundary element analysis (BEA), hybrid finite element analysis-statistical energy analysis (FEA-SEA) and statistical energy analysis (SEA), respectively. First, a new method named statistical acoustic energy flow (SAEF) is proposed, which can be applied to the full-spectrum HST interior noise simulation (including low, medium, and high frequencies) with only one model. In an SAEF model, the corresponding multi-physical-field coupling excitations are firstly fully considered and coupled to excite the interior noise. The interior noise attenuated by sound insulation panels of carriage is simulated through modeling the inflow acoustic energy from the exterior excitations into the interior acoustic cavities. Rigid multi-body dynamics, fast multi-pole BEA, and large-eddy simulation with indirect boundary element analysis are first employed to extract the multi-physical-field excitations, which include the wheel-rail interaction forces/secondary suspension forces, the wheel-rail rolling noise, and aerodynamic noise, respectively. All the peak values and their frequency bands of the simulated acoustic excitations are validated with those from the noise source identification test. Besides, the measured equipment noise inside equipment compartment is used as one of the excitation sources which contribute to the interior noise. Second, a full-trimmed FE carriage model is firstly constructed, and the simulated modal shapes and frequencies agree well with the measured ones, which has validated the global FE carriage model as well as the local FE models of the aluminum alloy-trim composite panel. Thus, the sound transmission loss model of any composite panel has indirectly been validated. Finally, the SAEF model of the carriage is constructed based on the accurate FE model and stimulated by the multi-physical-field excitations. The results show

Surface sensitive mode XAFS measurement of local structure of ordered Ge nanoclusters (quantum dots) on Si(0 0 1)

CERN Document Server

Erenburg, S B; Mazalov, L N; Nikiforov, A I; Stepina, N P; Nenashev, A V

2001-01-01

Pseudomorphous Ge films have been deposited on Si(0 0 1) substrate using molecular beam epitaxy at 300 deg. C up to the critical thickness of four monolayers. As a result of the following deposition pyramid-like Ge islands have been grown in Stranski-Krastanov mode. The islands revealing quantum dots (QD) properties are self-organized during the growth in uniform Ge nanostructures with lateral sizes approx 15 nm and height approx 1.5 nm. Ge K XAFS measurements have been performed using total electron yield detection mode. It was established that pseudomorphous 4-monolayer Ge films contain about 50% Si atoms. It has been found that the Ge QD are characterized by interatomic Ge-Ge distances of 2.41 A which is 0.04 A less than in bulk Ge.

Adaptive spectrum decision framework for heterogeneous dynamic spectrum access networks

CSIR Research Space (South Africa)

Masonta, M

2015-09-01

Full Text Available Spectrum decision is the ability of a cognitive radio (CR) system to select the best available spectrum band to satisfy dynamic spectrum access network (DSAN) users¿ quality of service (QoS) requirements without causing harmful interference...

Ampelopsin-induced reactive oxygen species enhance the apoptosis of colon cancer cells by activating endoplasmic reticulum stress-mediated AMPK/MAPK/XAF1 signaling

Science.gov (United States)

Park, Ga Bin; Jeong, Jee-Yeong; Kim, Daejin

2017-01-01

Ampelopsin (Amp) is bioactive natural product and exerts anti-cancer effects against several cancer types. The present study investigated the anti-colon cancer activity of Amp and explored its mechanism of action. The treatment of colon cancer cells with Amp resulted in the dose- and time-dependent induction of apoptosis via the activation of endoplasmic reticulum (ER) stress, 5′ adenosine monophosphate-activated protein kinase (AMPK), and c-Jun N-terminal protein kinase (JNK)/p38 mitogen-activated protein kinases (MAPKs). Salubrinal, an ER stress inhibitor, prevented the upregulation of ER stress-associated proteins, including phosphorylated protein kinase RNA-like ER kinase, phosphorylated eukaryotic translation initiation factor 2α, glucose-regulated protein 78, and CCAAT/enhancer-binding protein homologous protein, as well as suppressing AMPK activation and the MAPK signaling pathway. Knockdown of AMPK by RNA interference failed to block ER stress. Additionally, SP600125 (a JNK inhibitor) and SB203580 (a p38-MAPK inhibitor) effectively inhibited apoptosis and attenuated the expression of X-linked IAP-associated factor 1 (XAF1) and apoptotic Bcl-2 family proteins (BCL2 antagonist/killer 1 and BCL2-associated X protein) in Amp-treated colon cancer cells. Furthermore, reactive oxygen species (ROS)-mediated ER stress/AMPK apoptotic signaling pathway in Amp-treated colon cancer cells were markedly inhibited by treatment with N-acetyl-L-cysteine, a ROS scavenger. These results demonstrate that treatment with Amp induces the apoptotic death of colon cancer cells through ER stress-initiated AMPK/MAPK/XAF1 signaling. These results also provide experimental information for developing Amp as therapeutic drug against colon cancer. PMID:29250183

Effect of milling time and annealing temperature on nanoparticles evolution for 13.5% Cr ODS ferritic steel powders by joint application of XAFS and TEM

Science.gov (United States)

He, P.; Hoffmann, J.; Möslang, A.

2018-04-01

The characteristics of strengthening nanoparticles have a major influence on the mechanical property and irradiation resistance of oxide dispersion strengthened (ODS) steels. To determine how to control nanoparticles evolution, 0.3% Ti with 0.3% Y2O3 were added in 13.5%Cr pre-alloyed steel powders via different milling and consolidation conditions, then characterized by transmission electron microscopy (TEM) and X-ray absorption fine structure (XAFS) at synchrotron irradiation facility. The dissolution of Y2O3 is greatly dependent on the milling time at fixed milling speeds. After 24 h of milling, only minor amounts of the initially added Y2O3 dissolve into the steel matrix whereas TEM results reveal nearly complete dissolution of Y2O3 in 80-h-milled powder. The annealed powder FT-A800 (at 800 °C for 1 h) exhibits a structure near to the initially added Y2O3. The slightly deviation may be accounted for considerable lattice distortion related to the presence of atomic vacancies or formation of Y-Ti-O nucleus. The annealed powders FT-A1000 and FT-A1100 contain complex mixtures of Y-O/Y-Ti-O oxides, which cannot be fitted by any single thermally stable compounds. The coordination numbers of these first two shells in the annealed powders significantly raise as a function of the annealing temperature, indicating the formation of more ordered Y-O or Y-Ti-O particles. The extended X-ray absorption fine structure (EXAFS) spectrum could not necessarily distinguish the dominant oxide species.

KANSL1 gene disruption associated with the full clinical spectrum of 17q21.31 microdeletion syndrome

OpenAIRE

Moreno-Igoa, María; Hernández-Charro, Blanca; Bengoa-Alonso, Amaya; Pérez-Juana-del-Casal, Aranzazu; Romero-Ibarra, Carlos; Nieva-Echebarria, Beatriz; Ramos-Arroyo, María Antonia

2015-01-01

Background Chromosome 17q21.31 microdeletion syndrome is a multisystem genomic disorder caused by a recurrent 600-kb-long deletion, or haploinsufficiency of the chromatin modifier gene KANSL1, which maps to that region. Patients with KANSL1 intragenic mutations have been reported to display the major clinical features of 17q21.31 microdeletion syndrome. However, they did not exhibit the full clinical spectrum of this disorder, which might indicate that an additional gene or genes, located in ...

X ray absorption fine structure of systems in the anharmonic limit

Science.gov (United States)

Mustredeleon, J.; Conradson, S. D.; Batistic, I.; Bishop, A. R.; Raistrick, I.; Jackson, W. E.; Brown, G. E.

A new approach to the analysis of x-ray absorption fine structure (XAFS) data is presented. It is based on the use of radial distribution functions directly calculated from a single-particle ion Hamiltonian containing model potentials. The starting point of this approach is the statistical average of the XAFS for an atomic pair. This average can be computed using a radial distribution function (RDF), which can be expressed in terms of the eigenvalues and wavefunctions associated with the model potential. The pair potential describing the ionic motion is then expressed in terms of parameters that are determined by fitting this statistical average to the experimental XAFS spectrum. This approach allows the use of XAFS as a tool for mapping near-neighbor interatomic potentials, and allows the treatment of systems which exhibit strongly anharmonic potentials which can be treated by perturbative methods. Using this method we have analyzed the high temperature behavior of the oxygen contributions to the Fe K-edge XAFS in the ferrosilicate minerals andradite (Ca3Fe2Si3O12) and magnesiowustite (Mg(0.9)Fe(0.1)O). Using a temperature dependent anharmonic correction derived from these model compounds, we have found evidence for a local structural change in the Fe-O coordination environment upon melting of the geologically important mineral fayalite (Fe2SiO4). We have also employed this method to the study of the axial oxygen contributions to the polarized Cu K-edge XAFS on oriented samples of YBa2Cu3O7 and related compounds. From this study we find evidence for an axial oxygen-centered lattice distortion accompanying the superconducting phase transition and a correlation between this distortion and Tc. The relation of the observed lattice distortion to mechanisms of superconductivity is discussed.

X-ray absorption fine structure of systems in the anharmonic limit

International Nuclear Information System (INIS)

Mustre de Leon, J.; Conradson, S.D.; Batistic, I.; Bishop, A.R.; Raistrick, I.; Jackson, W.E.; Brown, G.E.

1991-01-01

A new approach to the analysis of x-ray absorption fine structure (XAFS) data is presented. It is based on the use of radial distribution functions directly calculated from a single-particle ion hamiltonian containing model potentials. The starting point of this approach is the statistical average of the XAFS for an atomic pair. This average can be computed using a radial distribution function (RDF), which can be expressed in terms of the eigenvalues and wavefunctions associated with the model potential. The pair potential describing the ionic motion is then expressed in terms of parameters that are determined by fitting this statistical average to the experimental XAFS spectrum. This approach allow the use of XAFS as a tool for mapping near-neighbor interatomic potentials, and allows the treatment of systems which exhibit strongly anharmonic potentials which can be treated by perturbative methods. Using this method we have analyzed the high temperature behavior of the oxygen contributions to the Fe K-edge XAFS in the ferrosilicate minerals andradite (Ca 3 Fe 2 Si 3 O 12 ) and magnesiowustite (Mg 0.9 Fe 0.1 O). Using a temperature dependent anharmonic correction derived from these model compounds, we have found evidence for a local structural change in the Fe-O coordination environment upon melting of the geologically important mineral fayalite (Fe 2 SiO 4 ). We have also employed this method to the study of the axial oxygen contributions to the polarized Cu K-edge XAFS on oriented samples of YBa 2 Cu 3 O 7 and related compounds. From this study we find evidence for an axial oxygen-centered lattice distortion accompanying the superconducting phase transition and a correlation between this distortion and T c . The relation of the observed lattice distortion to mechanisms of superconductivity is discussed. 33 refs., 6 figs

Recovering stellar population parameters via two full-spectrum fitting algorithms in the absence of model uncertainties

Science.gov (United States)

Ge, Junqiang; Yan, Renbin; Cappellari, Michele; Mao, Shude; Li, Hongyu; Lu, Youjun

2018-05-01

Using mock spectra based on Vazdekis/MILES library fitted within the wavelength region 3600-7350Å, we analyze the bias and scatter on the resulting physical parameters induced by the choice of fitting algorithms and observational uncertainties, but avoid effects of those model uncertainties. We consider two full-spectrum fitting codes: pPXF and STARLIGHT, in fitting for stellar population age, metallicity, mass-to-light ratio, and dust extinction. With pPXF we find that both the bias μ in the population parameters and the scatter σ in the recovered logarithmic values follows the expected trend μ ∝ σ ∝ 1/(S/N). The bias increases for younger ages and systematically makes recovered ages older, M*/Lr larger and metallicities lower than the true values. For reference, at S/N=30, and for the worst case (t = 108yr), the bias is 0.06 dex in M/Lr, 0.03 dex in both age and [M/H]. There is no significant dependence on either E(B-V) or the shape of the error spectrum. Moreover, the results are consistent for both our 1-SSP and 2-SSP tests. With the STARLIGHT algorithm, we find trends similar to pPXF, when the input E(B-V)values, with significantly underestimated dust extinction and [M/H], and larger ages and M*/Lr. Results degrade when moving from our 1-SSP to the 2-SSP tests. The STARLIGHT convergence to the true values can be improved by increasing Markov Chains and annealing loops to the "slow mode". For the same input spectrum, pPXF is about two order of magnitudes faster than STARLIGHT's "default mode" and about three order of magnitude faster than STARLIGHT's "slow mode".

The full spectrum of AdS5/CFT4 I: representation theory and one-loop Q-system

Science.gov (United States)

Marboe, Christian; Volin, Dmytro

2018-04-01

With the formulation of the quantum spectral curve for the AdS5/CFT4 integrable system, it became potentially possible to compute its full spectrum with high efficiency. This is the first paper in a series devoted to the explicit design of such computations, with no restrictions to particular subsectors being imposed. We revisit the representation theoretical classification of possible states in the spectrum and map the symmetry multiplets to solutions of the quantum spectral curve at zero coupling. To this end it is practical to introduce a generalisation of Young diagrams to the case of non-compact representations and define algebraic Q-systems directly on these diagrams. Furthermore, we propose an algorithm to explicitly solve such Q-systems that circumvents the traditional usage of Bethe equations and simplifies the computation effort. For example, our algorithm quickly obtains explicit analytic results for all 495 multiplets that accommodate single-trace operators in N=4 SYM with classical conformal dimension up to \\frac{13}{2} . We plan to use these results as the seed for solving the quantum spectral curve perturbatively to high loop orders in the next paper of the series.

Application of Monte Carlo method in determination of air absorbed rate from a full γ-ray spectrum

International Nuclear Information System (INIS)

Zhang Jiangyun; Huang Ning; Tang Lili; Liu Yanfang; Zhang Guanghua

2011-01-01

The dosimetric properties of a gamma-radiation field can be measured by a dose-rate meter or by a gamma-spectrometer with spectrum-dose conversion. One of the spectrum dose conversion methods is to evaluate the radiation dose directly from integrating the observed pulse height spectrum weighted by a G(E) function, instead of making spectrum analysis.In this paper,energy spectra of 11 single energy point sources in 0.1-2.5 MeV are simulated by using Monte Carlo software MCNP5 for NaI(Tl) detectors of Φ 75 mm x 75 mm, Φ 50 mm x 50 mm and Φ 25 mm x 25 mm. The energy spectra are used as standard spectrum to calculate the G(E) value, so as to calculate corresponding doses. Comparing the results with theoretical value,the error is less than 1.5%. Finally, the G(E)-based γ dose rate of radiation field agreed well (within 5%) with the dose rate measured by a dosimeter. (authors)

Full spectrum endoscopy (FUSE) versus standard forward-viewing endoscope (SFV) in a high-risk population

DEFF Research Database (Denmark)

Roepstorff, Søren; Hadi, Sabah Anwar; Rasmussen, Morten

2017-01-01

OBJECTIVES: To investigate the diagnostic performance of Full Spectrum Endoscopy (FUSE) compared to a conventional standard forward-viewing endoscope (SFV). The primary outcome was adenoma detection rate (ADR) and mean adenoma detection. Secondary outcome was feasibility of FUSE opposed to SFV...... intubation time, fentanyl and midazolam sedation, CRC detection, ADR, diverticulosis, bowel preparation, patient discomfort and endoscopist difficulty rating. Participants underwent FUSE colonoscopy on days when the FUSE system was available, while the remaining participants had SFV. All colonoscopies were.......1 ± 6.2 min in the FUSE and SFV groups (p = .040). ADR was 67.0% and 59.6% (p = .097), while the mean adenoma detection was 1.79 and 1.38 (p = .022) in the FUSE and SFV groups. Endoscopists reported increased difficulty rating with FUSE compared to SFV (p > .001). CONCLUSION: FUSE colonoscopy provides...

Full-spectrum light management by pseudo-disordered moth-eye structures for thin film solar cells.

Science.gov (United States)

Liu, Xiaojun; Da, Yun; Xuan, Yimin

2017-08-07

In this paper, the role of pseudo-disordered moth-eye structures on the optical features for application to thin-film solar cells is investigated to realize the superior light management for the full-spectrum solar energy utilization, compared with some ordered structures. Without loss of generality, the c-Si thin film solar cell is taken as the example. The results demonstrate that the fluctuations introduced into the geometry parameters of moth-eye elements can lead to the remarkable absorption enhancement in the wavelength region of 0.3-1.1 μm and high transmission in the wavelength range of 1.1-2.5 μm. Two mechanisms including the increasing spectral density of modes and the intensive forescattering intensity are identified to be responsible for the absorption enhancement. In addition, the optical characteristics of the moth-eye surface with both disordered height and disordered diameter are insensitive to the incident angle.

Determination of soil, sand and ore primordial radionuclide concentrations by full-spectrum analyses of high-purity germanium detector spectra

International Nuclear Information System (INIS)

Newman, R.T.; Lindsay, R.; Maphoto, K.P.; Mlwilo, N.A.; Mohanty, A.K.; Roux, D.G.; Meijer, R.J. de; Hlatshwayo, I.N.

2008-01-01

The full-spectrum analysis (FSA) method was used to determine primordial activity concentrations (ACs) in soil, sand and ore samples, in conjunction with a HPGe detector. FSA involves the least-squares fitting of sample spectra by linear combinations of 238 U, 232 Th and 40 K standard spectra. The differences between the FSA results and those from traditional windows analyses (using regions-of-interest around selected photopeaks) are less than 10% for all samples except zircon ore, where FSA yielded an unphysical 40 K AC

PTFE-based microreactor system for the continuous synthesis of full-visible-spectrum emitting cesium lead halide perovskite nanocrystals

Directory of Open Access Journals (Sweden)

Chengxi Zhang

2017-11-01

Full Text Available Colloidal perovskite nanocrystals comprised of all inorganic cesium lead halide (CsPbX3, X = Cl, Br, I or a mixture thereof have potential as optical gain materials due to their high luminescence efficiency. In this work, cesium lead halide nanocrystals are continuously synthesized via a microreactor system consisting of poly(tetrafluoroethylene (PTFE capillaries. The synthesized nanocrystals possess excellent optical properties, including a full width at half maximum of 19–35 nm, high fluorescence quantum yield of 47.8–90.55%, and photoluminescence emission in the range of 450–700 nm. For the same precursor concentrations, the photoluminescence emission peak generally increases with increasing reaction temperature, revealing a controllable temperature effect on the photoluminescence characteristics of the synthesized nanocrystals. For quantum dots synthesized with a Br/I ratio of 1:3, a slight blue shift was observed for reaction temperatures greater than 100 °C. This PTFE-based microreactor system provides the unique capability of continuously synthesizing high-quality perovskite nanocrystals that emit over the full visible spectrum with applications ranging from displays and optoelectronic devices.

Eigenvector decomposition of full-spectrum x-ray computed tomography.

Science.gov (United States)

Gonzales, Brian J; Lalush, David S

2012-03-07

Energy-discriminated x-ray computed tomography (CT) data were projected onto a set of basis functions to suppress the noise in filtered back-projection (FBP) reconstructions. The x-ray CT data were acquired using a novel x-ray system which incorporated a single-pixel photon-counting x-ray detector to measure the x-ray spectrum for each projection ray. A matrix of the spectral response of different materials was decomposed using eigenvalue decomposition to form the basis functions. Projection of FBP onto basis functions created a de facto image segmentation of multiple contrast agents. Final reconstructions showed significant noise suppression while preserving important energy-axis data. The noise suppression was demonstrated by a marked improvement in the signal-to-noise ratio (SNR) along the energy axis for multiple regions of interest in the reconstructed images. Basis functions used on a more coarsely sampled energy axis still showed an improved SNR. We conclude that the noise-resolution trade off along the energy axis was significantly improved using the eigenvalue decomposition basis functions.

Investigation of the Full Spectrum Phonon Lifetime in Thin Silicon Films from the Bulk Spectral Phonon Mean-Free-Path Distribution by Using Kinetic Theory

Energy Technology Data Exchange (ETDEWEB)

Jin, Jae Sik [Chosun College of Science and Technology, Gwangju (Korea, Republic of)

2017-03-15

Phonon dynamics in nanostructure is critically important to thermoelectric and optoelectronic devices because it determines the transport and other crucial properties. However, accurately evaluating the phonon lifetimes is extremely difficult. This study reports on the development of a new semi-empirical method to estimate the full-spectrum phonon lifetimes in thin silicon films at room temperature based on the experimental data on the phonon mean-free-path spectrum in bulk silicon and a phenomenological consideration of phonon transport in thin films. The bulk of this work describes the theory and the validation; then, we discuss the trend of the phonon lifetimes in thin silicon films when their thicknesses decrease.

Full Spectrum of Reported Symptoms of Bilateral Vestibulopathy Needs Further Investigation—A Systematic Review

Directory of Open Access Journals (Sweden)

Florence Lucieer

2018-06-01

Full Text Available ObjectiveTo systematically review the symptoms reported by patients with bilateral vestibulopathy (BV in clinical studies and case reports. This would serve as the first step in establishing a validated patient-reported outcome measures (PROM for BV.MethodsA search on symptoms reported by patients with BV was performed in PubMed, and all publications covering these symptoms were included. Exclusion criteria comprised reviews and insufficient details about the frequency of occurrence of symptoms.Results1,442 articles were retrieved. 88 studies were included (41 clinical studies, 47 case reports. In consensus, 68 descriptions of symptoms were classified into 6 common and generic symptoms. Frequency of symptoms in clinical studies and case reports were reviewed, respectively; imbalance (91 and 86%, chronic dizziness (58 and 62%, oscillopsia (50 and 70%, and recurrent vertigo (33 and 67%. BV could be accompanied by hearing loss (33 and 43% and tinnitus (15 and 36%. 15 clinical studies and 10 case reports reported symptoms beyond vestibular and hearing deficits such as limited social activities, depression, concentration, and memory impairment and reduced quality of life in general.ConclusionThe literature on BV symptomatology mainly focuses on classic symptoms such as imbalance and oscillopsia, while only few report additional symptoms such as cognitive memory impairment and performing dual tasks. In fact, none of the reviewed clinical studies and case reports provided a comprehensive overview of BV symptoms. To develop a validated PROM, qualitative research using semi-structured and unstructured interviews is needed to explore the full spectrum of BV symptoms.

Spectrum database as a service (SDaaS) for broadband innovation and efficient spectrum utilization

CSIR Research Space (South Africa)

Mfupe, L

2013-10-01

Full Text Available Broadband innovations for future wireless networks involves rapid sharing of radio frequency (RF) spectrum resources by means of dynamic spectrum access techniques (DSA) to satisfy immediate portfolio of heterogeneous demands of wireless IP services...

Full-spectrum photon management of solar cell structures for photovoltaic–thermoelectric hybrid systems

International Nuclear Information System (INIS)

Xu, Yuanpei; Xuan, Yimin; Yang, Lili

2015-01-01

Highlights: • A novel photon management method is proposed for hybrid photovoltaic–thermoelectric systems. • Composite structured surfaces enable creditable ultra-broadband anti-reflection property. • Incorporation of anti-reflection and light-trapping brings spectral absorption and transmission. • The efficient photon management of the structured surface is also omnidirectional. - Abstract: In this paper, a novel ultra-broadband photon management structure is proposed for crystalline silicon thin-film solar cells used in the photovoltaic–thermoelectric hybrid system. Nanostructures are employed on both front and back side. Optical behavior of the structure in ultra-broadband (300–2500 nm) are investigated through the Finite Difference Time Domain method. By combing moth-eye and inverted-parabolic surface, a new composite surface structure is proposed for anti-reflection in the ultra-broadband wavelengths. Front metallic nanoparticles, plasmonic back reflector and metallic gratings are studied for light-trapping and the effect of plasmonic back reflector is validated by the experimental data of the external quantum efficiency. The effects of incident angle are discussed for metallic gratings. Numerical computation shows that the incorporation of anti-reflection and light-trapping can obtain high absorption in the solar cell and ensure the rest incident light transmits to the thermoelectric generator efficiently. This work shows potential full-spectrum utilization of solar energy for various photovoltaic devices related with hybrid photovoltaic–thermoelectric systems

The Full Spectrum of Clinical Ethical Issues in Kidney Failure. Findings of a Systematic Qualitative Review.

Science.gov (United States)

Kahrass, Hannes; Strech, Daniel; Mertz, Marcel

2016-01-01

When treating patients with kidney failure, unavoidable ethical issues often arise. Current clinical practice guidelines some of them, but lack comprehensive information about the full range of relevant ethical issues in kidney failure. A systematic literature review of such ethical issues supports medical professionalism in nephrology, and offers a solid evidential base for efforts that aim to improve ethical conduct in health care. To identify the full spectrum of clinical ethical issues that can arise for patients with kidney failure in a systematic and transparent manner. A systematic review in Medline (publications in English or German between 2000 and 2014) and Google Books (with no restrictions) was conducted. Ethical issues were identified by qualitative text analysis and normative analysis. The literature review retrieved 106 references that together mentioned 27 ethical issues in clinical care of kidney failure. This set of ethical issues was structured into a matrix consisting of seven major categories and further first and second-order categories. The systematically-derived matrix helps raise awareness and understanding of the complexity of ethical issues in kidney failure. It can be used to identify ethical issues that should be addressed in specific training programs for clinicians, clinical practice guidelines, or other types of policies dealing with kidney failure.

ADAPTIVE FULL-SPECTRUM SOLAR ENERGY SYSTEMS CROSS-CUTTING R&D ON ADAPTIVE FULL-SPECTRUM SOLAR ENERGY SYSTEMS FOR MORE EFFICIENT AND AFFORDABLE USE OF SOLAR ENERGY IN BUILDINGS AND HYBRID PHOTOBIOREACTORS

Energy Technology Data Exchange (ETDEWEB)

Byard D. Wood; Jeff D. Muhs

2002-09-01

This RD&D project is a three year team effort to develop a hybrid solar lighting (HSL) system that transports day light from a paraboloidal dish concentrator to a luminaire via a large core polymer fiber optic. The luminaire can be a device to distribute sunlight into a space for the production of algae or it can be a device that is a combination of day lighting and fluorescent lighting for office lighting. In this project, the sunlight is collected using a one-meter paraboloidal concentrator dish with two-axis tracking. The secondary mirror consists of eight planar-segmented mirrors that direct the visible part of the spectrum to eight fibers (receiver) and subsequently to eight luminaires. This results in about 8,200 lumens incident at each fiber tip. Each fiber can illuminate about 16.7 m{sup 2} (180 ft{sup 2}) of office space. The IR spectrum is directed to a thermophotovoltaic array to produce electricity. This report describes eleven investigations on various aspects of the system. Taken as a whole, they confirm the technical feasibility of this technology.

Efficient full-spectrum utilization, reception and conversion of solar energy by broad-band nanospiral antenna.

Science.gov (United States)

Zhao, Huaqiao; Gao, Huotao; Cao, Ting; Li, Boya

2018-01-22

In this work, the collection of solar energy by a broad-band nanospiral antenna is investigated in order to solve the low efficiency of the solar rectenna based on conventional nanoantennas. The antenna impedance, radiation, polarization and effective area are all considered in the efficiency calculation using the finite integral technique. The wavelength range investigated is 300-3000 nm, which corresponds to more than 98% of the solar radiation energy. It's found that the nanospiral has stronger field enhancement in the gap than a nanodipole counterpart. And a maximum harvesting efficiency about 80% is possible in principle for the nanospiral coupled to a rectifier resistance of 200 Ω, while about 10% for the nanodipole under the same conditions. Moreover, the nanospiral could be coupled to a rectifier diode of high resistance more easily than the nanodipole. These results indicate that the efficient full-spectrum utilization, reception and conversion of solar energy can be achieved by the nanospiral antenna, which is expected to promote the solar rectenna to be a promising technology in the clean, renewable energy application.

Application of full spectrum analysis technique for NaI(TI) based gamma ray spectral monitoring system

International Nuclear Information System (INIS)

Pant, Amar D.; Verma, Amit K.; Narayani, K.; Anilkumar, S.; Singh, Rajvir

2016-01-01

NaI(Tl) is commonly used for the gamma spectrometry analysis in laboratories. It continues to be the first choice for gamma spectrometry in many applications even today. Many gamma spectrometric methods are developed to experimentally determine activity of radionuclides in samples. Detectors used worldwide for gamma radiation monitoring are either GM based or scintillator based detector based on count rate. For radiation early warning systems radionuclide specific radiation monitoring methodology is required i.e. gamma ray spectrometry based environmental monitoring system. A computer program has been developed for gamma spectral monitoring by the use of full spectrum analysis (FSA). In this measured spectra are fitted using individual spectral components by least square fitting (LSF). The method is found very useful in situations, where radionuclide specific environmental radiation monitoring is required. The paper describes the details of the FSA procedure for the on line acquisition and analysis of gamma ray spectra from Nal(Tl) detectors

Computing the full spectrum of large sparse palindromic quadratic eigenvalue problems arising from surface Green's function calculations

Science.gov (United States)

Huang, Tsung-Ming; Lin, Wen-Wei; Tian, Heng; Chen, Guan-Hua

2018-03-01

Full spectrum of a large sparse ⊤-palindromic quadratic eigenvalue problem (⊤-PQEP) is considered arguably for the first time in this article. Such a problem is posed by calculation of surface Green's functions (SGFs) of mesoscopic transistors with a tremendous non-periodic cross-section. For this problem, general purpose eigensolvers are not efficient, nor is advisable to resort to the decimation method etc. to obtain the Wiener-Hopf factorization. After reviewing some rigorous understanding of SGF calculation from the perspective of ⊤-PQEP and nonlinear matrix equation, we present our new approach to this problem. In a nutshell, the unit disk where the spectrum of interest lies is broken down adaptively into pieces small enough that they each can be locally tackled by the generalized ⊤-skew-Hamiltonian implicitly restarted shift-and-invert Arnoldi (G⊤SHIRA) algorithm with suitable shifts and other parameters, and the eigenvalues missed by this divide-and-conquer strategy can be recovered thanks to the accurate estimation provided by our newly developed scheme. Notably the novel non-equivalence deflation is proposed to avoid as much as possible duplication of nearby known eigenvalues when a new shift of G⊤SHIRA is determined. We demonstrate our new approach by calculating the SGF of a realistic nanowire whose unit cell is described by a matrix of size 4000 × 4000 at the density functional tight binding level, corresponding to a 8 × 8nm2 cross-section. We believe that quantum transport simulation of realistic nano-devices in the mesoscopic regime will greatly benefit from this work.

Full spectrum water

International Nuclear Information System (INIS)

Brannock, Matthew; Fergus, Ian; Griffiths, David

2011-01-01

Coal Seam Gas water (CSG) in Australia is typically brackish with high alkalinity and pH, and if not managed correctly may adversely affect the whole environment. To achieve a sustainable and holistic outcome for CSG associated water, an integrated approach is required where CSG producers working in close cooperation with all stakeholders, including the state and federal governments, regulators, community and land owners.

Full Spectrum LAR

Science.gov (United States)

2008-01-01

Emerson 901 TOW Under Armor (TUA) weapons system. When reliably operational, the Emerson 901 turret can still provide effective anti-armor fires as...the rear of the LAV-R thus there is no available space to carry ammunition resupplies, food, or under armor ambulance kits. On the other hand, the...the LAR battalion; however, the LAV-EFSS cannot be fired under armor protection or in the direct firing mode. Both the LAV-120 AMS and the LAV-EFSS

Principal component analysis of normalized full spectrum mass spectrometry data in multiMS-toolbox: An effective tool to identify important factors for classification of different metabolic patterns and bacterial strains.

Science.gov (United States)

Cejnar, Pavel; Kuckova, Stepanka; Prochazka, Ales; Karamonova, Ludmila; Svobodova, Barbora

2018-06-15

Explorative statistical analysis of mass spectrometry data is still a time-consuming step. We analyzed critical factors for application of principal component analysis (PCA) in mass spectrometry and focused on two whole spectrum based normalization techniques and their application in the analysis of registered peak data and, in comparison, in full spectrum data analysis. We used this technique to identify different metabolic patterns in the bacterial culture of Cronobacter sakazakii, an important foodborne pathogen. Two software utilities, the ms-alone, a python-based utility for mass spectrometry data preprocessing and peak extraction, and the multiMS-toolbox, an R software tool for advanced peak registration and detailed explorative statistical analysis, were implemented. The bacterial culture of Cronobacter sakazakii was cultivated on Enterobacter sakazakii Isolation Agar, Blood Agar Base and Tryptone Soya Agar for 24 h and 48 h and applied by the smear method on an Autoflex speed MALDI-TOF mass spectrometer. For three tested cultivation media only two different metabolic patterns of Cronobacter sakazakii were identified using PCA applied on data normalized by two different normalization techniques. Results from matched peak data and subsequent detailed full spectrum analysis identified only two different metabolic patterns - a cultivation on Enterobacter sakazakii Isolation Agar showed significant differences to the cultivation on the other two tested media. The metabolic patterns for all tested cultivation media also proved the dependence on cultivation time. Both whole spectrum based normalization techniques together with the full spectrum PCA allow identification of important discriminative factors in experiments with several variable condition factors avoiding any problems with improper identification of peaks or emphasis on bellow threshold peak data. The amounts of processed data remain still manageable. Both implemented software utilities are available

Listen and talk full-duplex cognitive radio networks

CERN Document Server

Liao, Yun; Han, Zhu

2016-01-01

This brief focuses on the use of full-duplex radio in cognitive radio networks, presenting a novel spectrum sharing protocol that allows the secondary users to simultaneously sense and access the vacant spectrum. This protocol, called “Listen-and-talk” (LAT), is evaluated by both mathematical analysis and computer simulations in comparison with other existing protocols, including the listen-before-talk protocol. In addition to LAT-based signal processing and resource allocation, the brief discusses techniques such as spectrum sensing and dynamic spectrum access. The brief proposes LAT as a suitable access scheme for cognitive radio networks, which can support the quality-of-service requirements of these high priority applications. Fundamental theories and key techniques of cognitive radio networks are also covered. Listen and Talk: Full-duplex Cognitive Radio Networks is designed for researchers, developers, and professionals involved in cognitive radio networks. Advanced-level students studying signal pr...

The full-sky relativistic correlation function and power spectrum of galaxy number counts. Part I: theoretical aspects

Science.gov (United States)

Tansella, Vittorio; Bonvin, Camille; Durrer, Ruth; Ghosh, Basundhara; Sellentin, Elena

2018-03-01

We derive an exact expression for the correlation function in redshift shells including all the relativistic contributions. This expression, which does not rely on the distant-observer or flat-sky approximation, is valid at all scales and includes both local relativistic corrections and integrated contributions, like gravitational lensing. We present two methods to calculate this correlation function, one which makes use of the angular power spectrum Cl(z1,z2) and a second method which evades the costly calculations of the angular power spectra. The correlation function is then used to define the power spectrum as its Fourier transform. In this work theoretical aspects of this procedure are presented, together with quantitative examples. In particular, we show that gravitational lensing modifies the multipoles of the correlation function and of the power spectrum by a few percent at redshift z=1 and by up to 30% and more at z=2. We also point out that large-scale relativistic effects and wide-angle corrections generate contributions of the same order of magnitude and have consequently to be treated in conjunction. These corrections are particularly important at small redshift, z=0.1, where they can reach 10%. This means in particular that a flat-sky treatment of relativistic effects, using for example the power spectrum, is not consistent.

A combined XAFS, ESI TOF-MS and LIBD study on the formation of polynuclear Zr(IV), Th(IV) and Pu(IV) species

Science.gov (United States)

Rothe, J.; Walther, C.; Brendebach, B.; Büchner, S.; Fuss, M.; Denecke, M. A.; Geckeis, H.

2009-11-01

The long term radiotoxicity of spent nuclear fuel disposed of in deep underground repositories after discharge from nuclear power reactors is determined by actinide elements, mainly plutonium. Water intrusion into the repository might cause container corrosion and leaching of the waste matrices, leading to the release of Pu and other actinides into the geological environment. Performance assessment for a future nuclear waste repository requires detailed knowledge on actinide aqueous chemistry in the aquifer surrounding the disposal site. Tetravalent actinides exhibit a strong tendency towards hydrolysis and subsequent polymerization and/or colloid formation. These species provide a potential pathway for migration of actinides away from the repository. Therefore, it is of fundamental interest to study their generation and properties in-situ. To this end, X-ray Absorption Fine Structure Spectroscopy (XAFS) at the INE-Beamline for actinide research at ANKA, Electrospray Mass-Spectrometry (ESI TOF-MS) and Laser Induced Breakdown Detection (LIBD) are combined at FZK-INE in a comprehensive attempt to characterize Zr(IV) (An(IV) analogue), Th(IV) and Pu(IV) polymerization and colloid formation.

Where do the doped holes go in La2-xSrxCuO4? A close look by XAFS

International Nuclear Information System (INIS)

Haskel, Daniel; Polinger, Victor; Stern, Edward A.

1999-01-01

Polarized x-ray absorption fine structure (XAFS) measurements at the La and Sr sites in La 2-x Sr x CuO 4 (0.075(less-or-similar sign)x(less-or-similar sign)0.35) indicate that doped holes introduced with Sr are not uniformly distributed in the CuO 2 planes but reside in impurity states with the majority of charge located on CuO 6 octahedra coupled to the Sr dopants by an apical oxygen (denoted as Sr octahedra). A model based on doped hole-induced Jahn Teller (JT) distortions of these Sr octahedra indicates the impurity states are overlapping singlet and triplet ones resulting from pairings of intrinsic and extrinsic holes. The more mobile singlet pairs reside in the CuO 2 planes, are bound by more than 0.1 eV and could Bose-condense into a superconducting state. The predominant appearance of (mostly) out-of plane triplet states at high x intimately related to the 2D-3D crossover in transport properties and could relate to the observed loss of high T c in the overdoped regime, as confinement of carriers to the CuO 2 planes is reduced. (c) 1999 American Institute of Physics

The full spectrum of handlebar injuries in children: a decade of experience.

Science.gov (United States)

Nataraja, R M; Palmer, C S; Arul, G S; Bevan, C; Crameri, J

2014-04-01

Traumatic paediatric handlebar injury (HBI) is known to occur with different vehicles, affect different body regions, and have substantial associated morbidity. However, previous handlebar injury research has focused on the specific combination of abdominal injury and bicycle riding. Our aim was to fully describe the epidemiology and resultant spectrum of injuries caused by a HBI. Retrospective data analysis of all paediatric patients (trauma registry over a 10-year period. Primary outcome was the HBI, its location and management. The effects of patient age, vehicle type, the impact region, and Injury Severity Score (ISS) were also evaluated. HBI patients were compared against a cohort injured while riding similar vehicles, but not having sustained a HBI. 1990 patients were admitted with a handlebar-equipped vehicle trauma; 236 (11.9%) having sustained a HBI. HBI patients were twice as likely to be aged between 6 and 14 years old compared with non-HBI patients (OR 2.2; 95% CI 1.5-3.2). 88.6% of the HBI patients sustained an isolated injury, and 45.3% had non-abdominal handlebar impact. There were no significant differences in median ISS (p=0.4) or need for operative intervention (OR 1.1; 95% CI 0.9-1.5) between HBI and non-HBI patients. HBI patients had a significantly longer LOS (1.8 days vs. 1.2 days; p=0.001), and more frequently required a major operation (OR 3.4; 95% CI 2.2-5.4). The majority of splenic, renal and hepatic injuries were managed conservatively. Although the majority of paediatric HBI is associated with both intra-abdominal injury and bicycle riding, it produces a spectrum of potentially serious injuries and patients are more likely to undergo major surgery. Therefore these patients should always be treated with a high degree of suspicion. Copyright © 2013. Published by Elsevier Ltd.

A full-dimensional multilayer multiconfiguration time-dependent Hartree study on the ultraviolet absorption spectrum of formaldehyde oxide

International Nuclear Information System (INIS)

Meng, Qingyong; Meyer, Hans-Dieter

2014-01-01

Employing the multilayer multiconfiguration time-dependent Hartree (ML-MCTDH) method in conjunction with the multistate multimode vibronic coupling Hamiltonian (MMVCH) model, we perform a full dimensional (9D) quantum dynamical study on the simplest Criegee intermediate, formaldehyde oxide, in five lower-lying singlet electronic states. The ultraviolet (UV) spectrum is then simulated by a Fourier transform of the auto-correlation function. The MMVCH model is built based on extensive MRCI(8e,8o)/aug-cc-pVTZ calculations. To ensure a fast convergence of the final calculations, a large number of ML-MCTDH test calculations is performed to find an appropriate multilayer separations (ML-trees) of the ML-MCTDH nuclear wave functions, and the dynamical calculations are carefully checked to ensure that the calculations are well converged. To compare the computational efficiency, standard MCTDH simulations using the same Hamiltonian are also performed. A comparison of the MCTDH and ML-MCTDH calculations shows that even for the present not-too-large system (9D here) the ML-MCTDH calculations can save a considerable amount of computational resources while producing identical spectra as the MCTDH calculations. Furthermore, the present theoretical B ~ 1 A ′ ←X ~ 1 A ′ UV spectral band and the corresponding experimental measurements [J. M. Beames, F. Liu, L. Lu, and M. I. Lester, J. Am. Chem. Soc. 134, 20045–20048 (2012); L. Sheps, J. Phys. Chem. Lett. 4, 4201–4205 (2013); W.-L. Ting, Y.-H. Chen, W. Chao, M. C. Smith, and J. J.-M. Lin, Phys. Chem. Chem. Phys. 16, 10438–10443 (2014)] are discussed. To the best of our knowledge, this is the first theoretical UV spectrum simulated for this molecule including nuclear motion beyond an adiabatic harmonic approximation

Spectrum decision in cognitive radio networks: a survey

CSIR Research Space (South Africa)

Masonta, MT

2012-11-01

Full Text Available provides an up-to-date survey of spectrum decision in CR networks (CRNs) and addresses issues of spectrum characterization (including PU activity modelling), spectrum selection and CR reconfiguration. For each of these issues, we highlight key open research...

Molecular Imaging in Schizophrenia Spectrum Disorders

NARCIS (Netherlands)

Klein, H.C.; Doorduin, J.; van Berckel, B.N.M.

2014-01-01

In this chapter, we aim to shed light on the schizophrenia spectrum disorders using molecular imaging. Schizophrenia spectrum disorders consist primarily of the disorders with full-blown psychosis in their course and are grouped in the DSM-IV category of schizophrenia and other psychotic disorders.

VG2 J/S/U/N/SS PWS EDITED SPECTRUM ANALYZER FULL RES V1.0

Data.gov (United States)

National Aeronautics and Space Administration — This data set includes nearly all measurements collected from the spectrum analyzer component of the Plasma Wave Spectrometer (PWS) onboard Voyager 2 for the entire...

Full Spectrum of LPS Activation in Alveolar Macrophages of Healthy Volunteers by Whole Transcriptomic Profiling.

Directory of Open Access Journals (Sweden)

Miguel Pinilla-Vera

Full Text Available Despite recent advances in understanding macrophage activation, little is known regarding how human alveolar macrophages in health calibrate its transcriptional response to canonical TLR4 activation. In this study, we examined the full spectrum of LPS activation and determined whether the transcriptomic profile of human alveolar macrophages is distinguished by a TIR-domain-containing adapter-inducing interferon-β (TRIF-dominant type I interferon signature. Bronchoalveolar lavage macrophages were obtained from healthy volunteers, stimulated in the presence or absence of ultrapure LPS in vitro, and whole transcriptomic profiling was performed by RNA sequencing (RNA-Seq. LPS induced a robust type I interferon transcriptional response and Ingenuity Pathway Analysis predicted interferon regulatory factor (IRF7 as the top upstream regulator of 89 known gene targets. Ubiquitin-specific peptidase (USP-18, a negative regulator of interferon α/β responses, was among the top up-regulated genes in addition to IL10 and USP41, a novel gene with no known biological function but with high sequence homology to USP18. We determined whether IRF-7 and USP-18 can influence downstream macrophage effector cytokine production such as IL-10. We show that IRF-7 siRNA knockdown enhanced LPS-induced IL-10 production in human monocyte-derived macrophages, and USP-18 overexpression attenuated LPS-induced production of IL-10 in RAW264.7 cells. Quantitative PCR confirmed upregulation of USP18, USP41, IL10, and IRF7. An independent cohort confirmed LPS induction of USP41 and IL10 genes. These results suggest that IRF-7 and predicted downstream target USP18, both elements of a type I interferon gene signature identified by RNA-Seq, may serve to fine-tune early cytokine response by calibrating IL-10 production in human alveolar macrophages.

Cloud based spectrum manager for future wireless regulatory environment

CSIR Research Space (South Africa)

Masonta, MT

2015-12-01

Full Text Available The regulatory environment in radio frequency spectrum management lags the advancement of wireless technologies, especially in the area of cognitive radio and dynamic spectrum access. In this paper we argue that the solution towards spectrum Pareto...

Full-Duplex Relay Selection in Cognitive Underlay Networks

KAUST Repository

Khafagy, Mohammad Galal; Alouini, Mohamed-Slim; Aissa, Sonia

2017-01-01

In this work, we analyze the performance of full-duplex relay selection (FDRS) in spectrum-sharing networks. Contrary to half-duplex relaying, full-duplex relaying (FDR) enables simultaneous listening/forwarding at the secondary relay(s), thereby

TVWS devices spectrum mask test and analysis

CSIR Research Space (South Africa)

Lamola, MM

2016-09-01

Full Text Available Dynamic Spectrum Access (DSA) plays a vital role in opportunistic access to spectrum. A key component of DSA is preventing interference to the incumbent (primary) user from the secondary user. We present the results of an experiment to analyze...

Model Atmosphere Spectrum Fit to the Soft X-Ray Outburst Spectrum of SS Cyg

Directory of Open Access Journals (Sweden)

V. F. Suleimanov

2015-02-01

Full Text Available The X-ray spectrum of SS Cyg in outburst has a very soft component that can be interpreted as the fast-rotating optically thick boundary layer on the white dwarf surface. This component was carefully investigated by Mauche (2004 using the Chandra LETG spectrum of this object in outburst. The spectrum shows broad ( ≈5 °A spectral features that have been interpreted as a large number of absorption lines on a blackbody continuum with a temperature of ≈250 kK. Because the spectrum resembles the photospheric spectra of super-soft X-ray sources, we tried to fit it with high gravity hot LTE stellar model atmospheres with solar chemical composition, specially computed for this purpose. We obtained a reasonably good fit to the 60–125 °A spectrum with the following parameters: Teff = 190 kK, log g = 6.2, and NH = 8 · 1019 cm−2, although at shorter wavelengths the observed spectrum has a much higher flux. The reasons for this are discussed. The hypothesis of a fast rotating boundary layer is supported by the derived low surface gravity.

Condensing Raman spectrum for single-cell phenotype analysis

KAUST Repository

Sun, Shiwei; Wang, Xuetao; Gao, Xin; Ren, Lihui; Su, Xiaoquan; Bu, Dongbo; Ning, Kang

2015-01-01

In this work, we have proposed an approach called rDisc to discretize the original Raman spectrum into only a few (usually less than 20) representative peaks (Raman shifts). The approach has advantages in removing noises, and condensing the original spectrum. In particular, effective signal processing procedures were designed to eliminate noise, utilising wavelet transform denoising, baseline correction, and signal normalization. In the discretizing process, representative peaks were selected to signicantly decrease the Raman data size. More importantly, the selected peaks are chosen as suitable to serve as key biological markers to differentiate species and other cellular features. Additionally, the classication performance of discretized spectra was found to be comparable to full spectrum having more than 1000 Raman shifts. Overall, the discretized spectrum needs about 5storage space of a full spectrum and the processing speed is considerably faster. This makes rDisc clearly superior to other methods for single-cell classication.

Full spectrum of the two-photon and the two-mode quantum Rabi models

International Nuclear Information System (INIS)

Dossa, Anselme F.; Avossevou, Gabriel Y. H.

2014-01-01

This paper is concerned with the rigorous analytical determination of the spectrum of the two-photon and the two-mode quantum Rabi models. To reach this goal, we exploit the hidden symmetries in these models by means of the unitary and similarity transformations in addition to the Bargmann-Fock space description. In each case, the purely quantum mechanical problem of the Rabi model studied is reduced to solutions for differential equations. This eventually gives a third-order differential equation for each of these models, which is reduced to a second-order differential equation by additional transformations. The analytical expressions of the wave functions describing the energy levels are obtained in terms of the confluent hypergeometric functions

Beyond the Spectrum: Rethinking Autism

Directory of Open Access Journals (Sweden)

Heather Thomas

2017-03-01

Full Text Available The "spectrum" has become the dominant metaphor for conceptualizing autism, with fundamental consequences for notions of disability, diversity, and normality. In this article, we draw on ethnographic research with autistic communities to explore how the notion of the autism spectrum has become a focus of explicit identification, reflection, and contestation. To further this inquiry, we place these debates into conversation with earlier debates regarding another spectrum—the Kinsey Scale, a "spectrum" for conceptualizing sexual orientation that first appeared in 1948 but has been critiqued since the 1970s. How might responses to the Kinsey Scale (like the Klein Grid contribute to rethinking the autism spectrum? This is a question about the cultural and political implications of metaphors and conceptual models. It is of broad importance because the spectrum metaphor is being extended to a range of conditions beyond autism itself. Our goal is thus to build on insights from sexuality studies as well as the insights of autistic persons, advocates, and researchers who wish to forestall the naturalization of "the spectrum." In doing so, we seek to contribute to a discussion of what alternative frameworks might bring to questions of social justice, ability, and human flourishing.

South Africa heading for dynamic spectrum management

CSIR Research Space (South Africa)

Lysko, Albert A

2016-09-01

Full Text Available  Africa heading for dynamic spectrum management — PolicyTracker: the spectrum management newsletter https://www.policytracker.com/headlines/south­africa­heading­for­dynamic­spectrum­management/?searchterm=lysko 1/2 South Africa heading for dynamic spectrum management Sep 26, 2016 by Albert Lysko South... characteristic of rural areas, which traditionally lag behind more commercially attractive urban areas. The technology is a bridge towards fully dynamic spectrum management and 5G. The ability to manage spectrum dynamically should significantly improve the utilization and availability of spectrum, especially in rural areas, as well as...

X-Ray Absorption Spectroscopy of Fe-Substituted Allophane and Imogolite

Science.gov (United States)

Baker, L. L.; Strawn, D. G.; Nickerson, R. D.; McDaniel, P.

2011-12-01

Martian rocks and sediments contain weathering products including clay minerals formed as a result of interaction between rocks and water, and these materials can act as important indicators of past surface conditions on Mars. Weathering of terrestrial volcanic rocks similar to those on Mars produces nano-sized, variably hydrated aluminosilicate and iron oxide minerals, including allophane, imogolite, halloysite, hisingerite, and ferrihydrite. The nanoaluminosilicates can contain isomorphically substituted Fe, which may affect their spectral and physical properties as well as their eventual recrystallization products. Detection and quantification of such minerals in natural environments on Earth is difficult due to their variable chemical composition and lack of long-range crystalline order. Their accurate detection and quantification on Mars requires a better understanding of how composition affects their spectral properties and evolution to more crystalline phases. Aluminosilicate nanoparticles of varying composition were synthesized with isomorphically substituted Fe at Fe:Al ratios of 1:100. Allophanes were synthesized with Al:Si ratios of 2:1, 1:1, and 1:3. The substituted Fe was probed using Fe K-edge X-ray absorption fine structure spectroscopy (XAFS). The XAFS spectrum contains information about the molecular environment surrounding the target atom, and is an ideal technique for studying poorly crystalline materials that are difficult to characterize using bulk methods such as XRD. The near-edge (XANES) and extended (EXAFS) portions of the XAFS spectrum were examined, and allophane backscattering paths were fit using coordinates for a modified nanoball model (1). XANES spectra rule out ferrihydrite in the synthetic samples, suggesting all Fe was incorporated into the aluminosilicate structure. The XAFS results suggest that Fe substituted into the allophane structure is present as Fe(III) in octahedral coordination in a well-ordered sheet. Some Fe

Dynamic event Tress applied to sequences Full Spectrum LOCA. Calculating the frequency of exceedance of damage by integrated Safety Analysis Methodology; Arboles de sucesos dinamicos aplicados a secuencias Full Spectrum LOCA. Calculo de la frequencia de excedencia del dano mediante la metodologia Analisis Integrados de Seguridad (ISA)

Energy Technology Data Exchange (ETDEWEB)

Gomez-Magan, J. J.; Fernandez, I.; Gil, J.; Marrao, H.; Queral, C.; Gonzalez-Cadelo, J.; Montero-Mayorga, J.; Rivas, J.; Ibane-Llano, C.; Izquierdo, J. M.; Sanchez-Perea, M.; Melendez, E.; Hortal, J.

2013-09-01

The Integrated Safety Analysis (ISA) methodology, developed by the Spanish Nuclear Safety council (CSN), has been applied to obtain the dynamic Event Trees (DETs) for full spectrum Loss of Coolant Accidents (LOCAs) of a Westinghouse 3-loop PWR plant. The purpose of this ISA application is to obtain the Damage Exceedance Frequency (DEF) for the LOCA Event Tree by taking into account the uncertainties in the break area and the operator actuation time needed to cool down and de pressurize reactor coolant system by means of steam generator. Simulations are performed with SCAIS, a software tool which includes a dynamic coupling with MAAP thermal hydraulic code. The results show the capability of the ISA methodology to obtain the DEF taking into account the time uncertainty in human actions. (Author)

Sum Utilization of Spectrum with Spectrum Handoff and Imperfect Sensing in Interweave Multi-Channel Cognitive Radio Networks

Directory of Open Access Journals (Sweden)

Waqas Khalid

2018-05-01

Full Text Available Fifth-generation (5G heterogeneous network deployment poses new challenges for 5G-based cognitive radio networks (5G-CRNs as the primary user (PU is required to be more active because of the small cells, random user arrival, and spectrum handoff. Interweave CRNs (I-CRNs improve spectrum utilization by allowing opportunistic spectrum access (OSA for secondary users (SUs. The sum utilization of spectrum, i.e., joint utilization of spectrum by the SU and PU, depends on the spatial and temporal variations of PU activities, sensing outcomes, transmitting conditions, and spectrum handoff. In this study, we formulate and analyze the sum utilization of spectrum with different sets of channels under different PU and SU co-existing network topologies. We consider realistic multi-channel scenarios for the SU, with each channel licensed to a PU. The SU, aided by spectrum handoff, is authorized to utilize the channels on the basis of sensing outcomes and PU interruptions. The numerical evaluation of the proposed work is presented under different network and sensing parameters. Moreover, the sum utilization gain is investigated to analyze the sensitivities of different sensing parameters. It is demonstrated that different sets of channels, PU activities, and sensing outcomes have a significant impact on the sum utilization of spectrum associated with a specific network topology.

Spectrum estimation method based on marginal spectrum

International Nuclear Information System (INIS)

Cai Jianhua; Hu Weiwen; Wang Xianchun

2011-01-01

FFT method can not meet the basic requirements of power spectrum for non-stationary signal and short signal. A new spectrum estimation method based on marginal spectrum from Hilbert-Huang transform (HHT) was proposed. The procession of obtaining marginal spectrum in HHT method was given and the linear property of marginal spectrum was demonstrated. Compared with the FFT method, the physical meaning and the frequency resolution of marginal spectrum were further analyzed. Then the Hilbert spectrum estimation algorithm was discussed in detail, and the simulation results were given at last. The theory and simulation shows that under the condition of short data signal and non-stationary signal, the frequency resolution and estimation precision of HHT method is better than that of FFT method. (authors)

Dynamic event Tress applied to sequences Full Spectrum LOCA. Calculating the frequency of excedeence of damage by integrated Safety Analysis Methodology

International Nuclear Information System (INIS)

Gomez-Magan, J. J.; Fernandez, I.; Gil, J.; Marrao, H.; Queral, C.; Gonzalez-Cadelo, J.; Montero-Mayorga, J.; Rivas, J.; Ibane-Llano, C.; Izquierdo, J. M.; Sanchez-Perea, M.; Melendez, E.; Hortal, J.

2013-01-01

The Integrated Safety Analysis (ISA) methodology, developed by the Spanish Nuclear Safety council (CSN), has been applied to obtain the dynamic Event Trees (DETs) for full spectrum Loss of Coolant Accidents (LOCAs) of a Westinghouse 3-loop PWR plant. The purpose of this ISA application is to obtain the Damage Excedence Frequency (DEF) for the LOCA Event Tree by taking into account the uncertainties in the break area and the operator actuation time needed to cool down and de pressurize reactor coolant system by means of steam generator. Simulations are performed with SCAIS, a software tool which includes a dynamic coupling with MAAP thermal hydraulic code. The results show the capability of the ISA methodology to obtain the DEF taking into account the time uncertainty in human actions. (Author)

The Spectrum of the Universe.

Science.gov (United States)

Hill, Ryley; Masui, Kiyoshi W; Scott, Douglas

2018-05-01

Cosmic background (CB) radiation, encompassing the sum of emission from all sources outside our own Milky Way galaxy across the entire electromagnetic spectrum, is a fundamental phenomenon in observational cosmology. Many experiments have been conceived to measure it (or its constituents) since the extragalactic Universe was first discovered; in addition to estimating the bulk (cosmic monopole) spectrum, directional variations have also been detected over a wide range of wavelengths. Here we gather the most recent of these measurements and discuss the current status of our understanding of the CB from radio to γ-ray energies. Using available data in the literature, we piece together the sky-averaged intensity spectrum and discuss the emission processes responsible for what is observed. We examine the effect of perturbations to the continuum spectrum from atomic and molecular line processes and comment on the detectability of these signals. We also discuss how one could, in principle, obtain a complete census of the CB by measuring the full spectrum of each spherical harmonic expansion coefficient. This set of spectra of multipole moments effectively encodes the entire statistical history of nuclear, atomic, and molecular processes in the Universe.

Gauging the Fullness of our Full Spectrum Operations

Science.gov (United States)

2010-05-21

Systems Engineer Peter Checkland , who offered the observation that, “The complexity of problematical situations in real life stems from the fact that...2002), 44. 18 Linn, The Echo of Battle, 5. 19 Ibid., 233-234. 20 Peter Checkland and J. Poulter, Learning for Action: A Short Definitive Account of...Builder, Carl H. The Masks of War: American Styles in Strategy and Analysis. Baltimore, MD: John Hopkins University Press, 1989. Checkland

Spectrum 101: An Introduction to Spectrum Management

Science.gov (United States)

2004-03-01

produces a Joint Restricted Frequency List (JRFL). The JFRL consolidates and classifies the spectrum uses that are most critical to operations and to...Management Office JRFL Joint Restricted Frequency List JSC Joint Spectrum Center JSIR Joint Spectrum Interference Resolution JSME Joint Spectrum...Multifunctional Information Distribution System MILSATCOM Military Satellite Communications MOA Memorandum of Agreement MRFL Master Radio Frequency

Organic Microcrystal Vibronic Lasers with Full-Spectrum Tunable Output beyond the Franck-Condon Principle.

Science.gov (United States)

Dong, Haiyun; Zhang, Chunhuan; Liu, Yuan; Yan, Yongli; Hu, Fengqin; Zhao, Yong Sheng

2018-03-12

The very broad emission bands of organic semiconductor materials are, in theory, suitable for achieving versatile solid-state lasers; however, most of organic materials only lase at short wavelength corresponding to the 0-1 transition governed by the Franck-Condon (FC) principle. A strategy is developed to overcome the limit of FC principle for tailoring the output of microlasers over a wide range based on the controlled vibronic emission of organic materials at microcrystal state. For the first time, the output wavelength of organic lasers is tailored across all vibronic (0-1, 0-2, 0-3, and even 0-4) bands spanning the entire emission spectrum. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Spectrum

DEFF Research Database (Denmark)

Høgfeldt Hansen, Leif

2016-01-01

The publication functions as a proces description of the development and construction of an urban furniture SPECTRUM in the city of Gwangju, Republic of Korea. It is used as the cataloque for the exhibition of Spectrum.......The publication functions as a proces description of the development and construction of an urban furniture SPECTRUM in the city of Gwangju, Republic of Korea. It is used as the cataloque for the exhibition of Spectrum....

Resource Distribution Approaches in Spectrum Sharing Systems

Directory of Open Access Journals (Sweden)

Friedrich K. Jondral

2008-05-01

Full Text Available It is increasingly difficult to satisfy growing demands for spectrum with the conventional policy of fixed spectrum allocation. To overcome this problem, flexible/dynamic spectrum sharing methods that can significantly improve spectrum utilization of the spectrum have gained increasing interest recently. This paper presents two dynamic spectrum sharing approaches, a centralized and a decentralized one. The centralized approach is based on hierarchical trading. Each level of hierarchy is composed of “markets” that are associated with a certain spatial area and trading occurrence frequency, whereas area size and trading occurrence frequency depend on the hierarchy level. The decentralized approach is based on game-theory. There, it is assumed that the operators are averse to unequal payoffs and act unselfishly, enabling a stable and sustainable community. Numerical results show that, in the observed scenario, both proposals outperform the reference case of fixed resource allocation significantly in terms of utilized bandwidth. Whereas, negotiation costs for spectrum brokerage appear in the centralized approach, nonnegligible amounts of spectrum are lost in the decentralized approach due to collisions. Thus, a hybrid of centralized and decentralized approach that exploits the benefits of both is also considered.

Adaptive Full-Spectrum Solar Energy Systems Cross-Cutting R&D on adaptive full-spectrum solar energy systems for more efficient and affordable use of solar energy in buildings and hybrid photobioreactors

Energy Technology Data Exchange (ETDEWEB)

Wood, Byard; Kim, Kwang

2006-03-30

This RD&D project is a multi-institutional effort to develop a hybrid solar lighting (HSL) system that transports daylight from a paraboloidal dish concentrator to a luminaire via a bundle of polymer fiber optics. The luminaire can be a device to distribute sunlight into a space for the production of algae for CO{sub 2} sequestration or it can be a device that is a combination of daylighting and electric lighting for space/task lighting. In this project, the sunlight is collected using a one-meter paraboloidal concentrator dish with two-axis tracking. For the third generation (beta) system, the secondary mirror is an ellipsoidal mirror that directs the visible light into a bundle of 3 mm diameter fibers. The IR spectrum is filtered out to minimize unnecessary heating at the fiber entrance region. This report describes the major achievements from this research that began in August 2001.

Reconstructing Face Image from the Thermal Infrared Spectrum to the Visible Spectrum

Directory of Open Access Journals (Sweden)

Brahmastro Kresnaraman

2016-04-01

Full Text Available During the night or in poorly lit areas, thermal cameras are a better choice instead of normal cameras for security surveillance because they do not rely on illumination. A thermal camera is able to detect a person within its view, but identification from only thermal information is not an easy task. The purpose of this paper is to reconstruct the face image of a person from the thermal spectrum to the visible spectrum. After the reconstruction, further image processing can be employed, including identification/recognition. Concretely, we propose a two-step thermal-to-visible-spectrum reconstruction method based on Canonical Correlation Analysis (CCA. The reconstruction is done by utilizing the relationship between images in both thermal infrared and visible spectra obtained by CCA. The whole image is processed in the first step while the second step processes patches in an image. Results show that the proposed method gives satisfying results with the two-step approach and outperforms comparative methods in both quality and recognition evaluations.

ADAPTIVE FULL-SPECTRUM SOLAR ENERGY SYSTEMS Cross-Cutting R & D on adaptive full-spectrum solar energy systems for more efficient and affordable use of solar energy in buildings and hybrid photobioreactors

Energy Technology Data Exchange (ETDEWEB)

Byard D. Wood; David L. Beshears

2006-02-01

This RD&D project is a three year team effort to develop a hybrid solar lighting (HSL) system that transports daylight from a paraboloidal dish concentrator to a luminaire via a bundle of polymer fiber optics. The luminaire can be a device to distribute sunlight into a space for the production of algae or it can be a device that is a combination of daylighting and electric lighting for space/task lighting. In this project, the sunlight is collected using a one-meter paraboloidal concentrator dish with two-axis tracking. For the third generation (beta) system, the secondary mirror is an ellipsoidal mirror that directs the visible light into a bundle of 3 mm diameter fibers. The IR spectrum is filtered out to minimize unnecessary heating at the fiber entrance region. This report describes the following investigations: Niche applications for HSL technology, Luminaire design characteristics for linear and point lighting fixtures, and Daylight affects on productivity.

Does sex influence the diagnostic evaluation of autism spectrum disorder in adults?

Science.gov (United States)

Wilson, C Ellie; Murphy, Clodagh M; McAlonan, Grainne; Robertson, Dene M; Spain, Debbie; Hayward, Hannah; Woodhouse, Emma; Deeley, P Quinton; Gillan, Nicola; Ohlsen, J Chris; Zinkstok, Janneke; Stoencheva, Vladimira; Faulkner, Jessica; Yildiran, Hatice; Bell, Vaughan; Hammond, Neil; Craig, Michael C; Murphy, Declan GM

2016-01-01

It is unknown whether sex influences the diagnostic evaluation of autism spectrum disorder, or whether male and female adults within the spectrum have different symptom profiles. This study reports sex differences in clinical outcomes for 1244 adults (935 males and 309 females) referred for autism spectrum disorder assessment. Significantly, more males (72%) than females (66%) were diagnosed with an autism spectrum disorder of any subtype (x2 = 4.09; p = 0.04). In high-functioning autism spectrum disorder adults (IQ > 70; N = 827), there were no significant sex differences in severity of socio-communicative domain symptoms. Males had significantly more repetitive behaviours/restricted interests than females (p = 0.001, d = 0.3). A multivariate analysis of variance indicated a significant interaction between autism spectrum disorder subtype (full-autism spectrum disorder/partial-autism spectrum disorder) and sex: in full-autism spectrum disorder, males had more severe socio-communicative symptoms than females; for partial-autism spectrum disorder, the reverse was true. There were no sex differences in prevalence of co-morbid psychopathologies. Sex influenced diagnostic evaluation in a clinical sample of adults with suspected autism spectrum disorder. The sexes may present with different manifestations of the autism spectrum disorder phenotype and differences vary by diagnostic subtype. Understanding and awareness of adult female repetitive behaviours/restricted interests warrant attention and sex-specific diagnostic assessment tools may need to be considered. PMID:26802113

Study on accumulation mechanism of Cu and Pb in moss, Scopelophila cataractae, by micro-XRF imaging and XAFS analysis

International Nuclear Information System (INIS)

Yoshii, Yuichi; Nakai, Izumi; Hokura, Akiko; Abe, Tomoko; Itouga, Misao; Sakakibara, Hitoshi; Terada, Yasuko

2011-01-01

Scopelophila cataractae is known as a 'copper moss'. It is known as a peculiar moss which can accumulate high level of metals (Cu, Pb, etc.) in its plant body. This moss is expected as a material to collect metals from water. In this study, gametophyte's leaf of the moss was examined by μ-XRF imaging, and Cu K-edge and Pb L 1 -, L 3 -edge XAFS analyses to reveal the accumulation behavior of Cu and Pb. μ-XRF imaging was carried out utilizing X-ray microbeam at BL37XU, SPring-8 from the undulator source, and at BL-4A, Photon Factory KEK from the bending magnet. The results have revealed that Cu and Pb were accumulated on the cell wall of the leaf, and especially at the stereid cells of midrib. It was found that Cu-XANES spectra of the leaf were similar to that of copper(II) acetate, a reference substance. On the other hand, Pb XANES spectra of the leaf were similar to that of a reference, lead(II) stearate. These results suggested that these metals were bound to oxygen of carboxyl group in the plant. Consequently, it is assumed that Cu and Pb could be bound to acidic sugar which is a component of its cell wall such as pectic acid, polygalacturonic acid and others. Furthermore, to compare with other heavy-metal accumulating moss (Scopelophila ligulata and Sphagnum palustre), their gametophyte's leaves were also examined by μ-XRF imaging. S. ligulata accumulated Pb in its stereid cells of midlib, while S. palustre accumulated Pb in its hyaline cells. (author)

Determination of QW laser diode degradation based on the emission spectrum

Directory of Open Access Journals (Sweden)

Bliznyuk Vladimir

2017-01-01

Full Text Available The possibility of laser diodes degradation control by monitoring of their spectrum is shown. For red and infra-red laser diodes, the time dependence of the radiation spectrum width was obtained.

Transgenic potato (Solanum tuberosum) tubers synthesize the full spectrum of inulin molecules naturally occurring in globe artichoke (Cynara scolymus) roots

Science.gov (United States)

Hellwege, Elke M.; Czapla, Sylvia; Jahnke, Anuschka; Willmitzer, Lothar; Heyer, Arnd G.

2000-01-01

The ability to synthesize high molecular weight inulin was transferred to potato plants via constitutive expression of the 1-SST (sucrose:sucrose 1-fructosyltransferase) and the 1-FFT (fructan: fructan 1-fructosyltransferase) genes of globe artichoke (Cynara scolymus). The fructan pattern of tubers from transgenic potato plants represents the full spectrum of inulin molecules present in artichoke roots as shown by high-performance anion exchange chromatography, as well as size exclusion chromatography. These results demonstrate in planta that the enzymes sucrose:sucrose 1-fructosyltransferase and fructan:fructan 1-fructosyltransferase are sufficient to synthesize inulin molecules of all chain lengths naturally occurring in a given plant species. Inulin made up 5% of the dry weight of transgenic tubers, and a low level of fructan production also was observed in fully expanded leaves. Although inulin accumulation did not influence the sucrose concentration in leaves or tubers, a reduction in starch content occurred in transgenic tubers, indicating that inulin synthesis did not increase the storage capacity of the tubers. PMID:10890908

Comparison of conventional and total reflection excitation geometry for fluorescence X-ray absorption spectroscopy on droplet samples

International Nuclear Information System (INIS)

Falkenberg, G.; Pepponi, G.; Streli, C.; Wobrauschek, P.

2003-01-01

X-ray absorption fine structure (XAFS) experiments in fluorescence mode have been performed in total reflection excitation geometry and conventional 45 deg. /45 deg. excitation/detection geometry for comparison. The experimental results have shown that XAFS measurements are feasible under normal total reflection X-ray fluorescence (TXRF) conditions, i.e. on droplet samples, with excitation in grazing incidence and using a TXRF experimental chamber. The application of the total reflection excitation geometry for XAFS measurements increases the sensitivity compared to the conventional geometry leading to lower accessible concentration ranges. However, XAFS under total reflection excitation condition fails for highly concentrated samples because of the self-absorption effect

Dale Sayers Festschrift

International Nuclear Information System (INIS)

Stern, Edward A.

2007-01-01

This Festschrift is in honor of Dale Sayers who passed away in November 2004. Dale played a pivotal role in initiating the modern era of X-ray Absorption Fine Structure (XAFS) 35 years ago. The prehistory of XAFS before the modern era consisted of 40 years of confusion caused by Kronig's two different theories of the extended XAFS (EXAFS), the Short-Range Order (SRO) and Long-Range Order (LRO) theories. Dale's PhD thesis on EXAFS led to the idea of a Fourier transform to definitely prove that SRO is the correct theory and then to the development of XAFS as a structure determination technique

A robust power spectrum split cancellation-based spectrum sensing method for cognitive radio systems

International Nuclear Information System (INIS)

Qi Pei-Han; Li Zan; Si Jiang-Bo; Gao Rui

2014-01-01

Spectrum sensing is an essential component to realize the cognitive radio, and the requirement for real-time spectrum sensing in the case of lacking prior information, fading channel, and noise uncertainty, indeed poses a major challenge to the classical spectrum sensing algorithms. Based on the stochastic properties of scalar transformation of power spectral density (PSD), a novel spectrum sensing algorithm, referred to as the power spectral density split cancellation method (PSC), is proposed in this paper. The PSC makes use of a scalar value as a test statistic, which is the ratio of each subband power to the full band power. Besides, by exploiting the asymptotic normality and independence of Fourier transform, the distribution of the ratio and the mathematical expressions for the probabilities of false alarm and detection in different channel models are derived. Further, the exact closed-form expression of decision threshold is calculated in accordance with Neyman—Pearson criterion. Analytical and simulation results show that the PSC is invulnerable to noise uncertainty, and can achive excellent detection performance without prior knowledge in additive white Gaussian noise and flat slow fading channels. In addition, the PSC benefits from a low computational cost, which can be completed in microseconds. (interdisciplinary physics and related areas of science and technology)

A robust power spectrum split cancellation-based spectrum sensing method for cognitive radio systems

Science.gov (United States)

Qi, Pei-Han; Li, Zan; Si, Jiang-Bo; Gao, Rui

2014-12-01

Spectrum sensing is an essential component to realize the cognitive radio, and the requirement for real-time spectrum sensing in the case of lacking prior information, fading channel, and noise uncertainty, indeed poses a major challenge to the classical spectrum sensing algorithms. Based on the stochastic properties of scalar transformation of power spectral density (PSD), a novel spectrum sensing algorithm, referred to as the power spectral density split cancellation method (PSC), is proposed in this paper. The PSC makes use of a scalar value as a test statistic, which is the ratio of each subband power to the full band power. Besides, by exploiting the asymptotic normality and independence of Fourier transform, the distribution of the ratio and the mathematical expressions for the probabilities of false alarm and detection in different channel models are derived. Further, the exact closed-form expression of decision threshold is calculated in accordance with Neyman—Pearson criterion. Analytical and simulation results show that the PSC is invulnerable to noise uncertainty, and can achive excellent detection performance without prior knowledge in additive white Gaussian noise and flat slow fading channels. In addition, the PSC benefits from a low computational cost, which can be completed in microseconds.

Oculoauriculovertebral spectrum with radial anomaly in child

Directory of Open Access Journals (Sweden)

Amar Taksande

2013-01-01

Full Text Available Oculoauriculovertebral spectrum (OAVS or Goldenhar syndrome is a wide spectrum of congenital anomalies that involves structures arising from the first and second branchial arches. It is characterized by a wide spectrum of symptoms and physical features. These abnormalities mainly involve the cheekbones, jaws, mouth, ears, eyes, or vertebrae. Other conditions with ear and/or radial involvement, such as, the Nager syndrome, Holt-Oram syndrome, Radial-renal syndrome, facioauriculoradial dysplasia, Fanconi anemia, and Vertebral, Anal atresia, Cardiac, Trachea, Esophageal, Renal, and Limb (VACTERL association should be considered for differential diagnosis. Here we report a child who had facial asymmetry, microsomia, microtia, congenital facial nerve palsy, conductive hearing loss, skin tags, iris coloboma, and preaxial polydactyly.

Special features of local spatial spectrum of Bessel light beams

CSIR Research Space (South Africa)

Belyi, VN

2011-11-01

Full Text Available In this paper the authors consider the angular spectrum of an apertured Bessel beam when the aperture is circular and shifted laterally with respect to the optical axis. Since the perturbation of the resulting angular spectrum is due to a spatially...

Adult Autism Subthreshold Spectrum (AdAS Spectrum): Validation of a questionnaire investigating subthreshold autism spectrum.

Science.gov (United States)

Dell'Osso, L; Gesi, C; Massimetti, E; Cremone, I M; Barbuti, M; Maccariello, G; Moroni, I; Barlati, S; Castellini, G; Luciano, M; Bossini, L; Rocchetti, M; Signorelli, M; Aguglia, E; Fagiolini, A; Politi, P; Ricca, V; Vita, A; Carmassi, C; Maj, M

2017-02-01

Increasing literature has shown the usefulness of a dimensional approach to autism. The present study aimed to determine the psychometric properties of the Adult Autism Subthreshold Spectrum (AdAS Spectrum), a new questionnaire specifically tailored to assess subthreshold forms of autism spectrum disorder (ASD) in adulthood. 102 adults endorsing at least one DSM-5 symptom criterion for ASD (ASDc), 143 adults diagnosed with a feeding and eating disorder (FED), and 160 subjects with no mental disorders (CTL), were recruited from 7 Italian University Departments of Psychiatry and administered the following: SCID-5, Autism-Spectrum Quotient (AQ), Ritvo Autism and Asperger Diagnostic Scale 14-item version (RAADS-14), and AdAS Spectrum. The AdAS Spectrum demonstrated excellent internal consistency for the total score (Kuder-Richardson's coefficient=.964) as well as for five out of seven domains (all coefficients>.80) and sound test-retest reliability (ICC=.976). The total and domain AdAS Spectrum scores showed a moderate to strong (>.50) positive correlation with one another and with the AQ and RAADS-14 total scores. ASDc subjects reported significantly higher AdAS Spectrum total scores than both FED (pcriteria (FED 0 ) and those with one ASD symptom criterion (FED 1 ) , a gradient of severity in AdAS Spectrum scores from CTL subjects to ASD patients, across FED 0 , ASD 1 , FED 1 was shown. The AdAS Spectrum showed excellent internal consistency and test-retest reliability and strong convergent validity with alternative dimensional measures of ASD. The questionnaire performed differently among the three diagnostic groups and enlightened some significant effects of gender in the expression of autistic traits. Copyright © 2016 Elsevier Inc. All rights reserved.

Maximally resolved anharmonic OH vibrational spectrum of the water/ZnO(101 \\xAF 0) interface from a high-dimensional neural network potential

Science.gov (United States)

Quaranta, Vanessa; Hellström, Matti; Behler, Jörg; Kullgren, Jolla; Mitev, Pavlin D.; Hermansson, Kersti

2018-06-01

Unraveling the atomistic details of solid/liquid interfaces, e.g., by means of vibrational spectroscopy, is of vital importance in numerous applications, from electrochemistry to heterogeneous catalysis. Water-oxide interfaces represent a formidable challenge because a large variety of molecular and dissociated water species are present at the surface. Here, we present a comprehensive theoretical analysis of the anharmonic OH stretching vibrations at the water/ZnO(101 ¯ 0) interface as a prototypical case. Molecular dynamics simulations employing a reactive high-dimensional neural network potential based on density functional theory calculations have been used to sample the interfacial structures. In the second step, one-dimensional potential energy curves have been generated for a large number of configurations to solve the nuclear Schrödinger equation. We find that (i) the ZnO surface gives rise to OH frequency shifts up to a distance of about 4 Å from the surface; (ii) the spectrum contains a number of overlapping signals arising from different chemical species, with the frequencies decreasing in the order ν(adsorbed hydroxide) > ν(non-adsorbed water) > ν(surface hydroxide) > ν(adsorbed water); (iii) stretching frequencies are strongly influenced by the hydrogen bond pattern of these interfacial species. Finally, we have been able to identify substantial correlations between the stretching frequencies and hydrogen bond lengths for all species.

Towards dynamic spectrum access and 5G, via television white spaces

CSIR Research Space (South Africa)

Lysko, Albert A

2017-05-01

Full Text Available allocations towards sharing the spectrum between different technologies in a dynamic fashion. The key focus will be on the developments in television white space and geolocation spectrum database methods and technologies, with mention of parallels to LTE....

Uranium, radium and thorium in soils with high-resolution gamma spectroscopy, MCNP-generated efficiencies, and VRF non-linear full-spectrum nuclide shape fitting

Directory of Open Access Journals (Sweden)

Metzger Robert

2017-01-01

Full Text Available A new method for analysis of uranium and radium in soils by gamma spectroscopy has been developed using VRF (“Visual RobFit” which, unlike traditional peak-search techniques, fits full-spectrum nuclide shapes with non-linear least-squares minimization of the chi-squared statistic. Gamma efficiency curves were developed for a 500 mL Marinelli beaker geometry as a function of soil density using MCNP. Collected spectra were then analyzed using the MCNP-generated efficiency curves and VRF to deconvolute the 90 keV peak complex of uranium and obtain 238U and 235U activities. 226Ra activity was determined either from the radon daughters if the equilibrium status is known, or directly from the deconvoluted 186 keV line. 228Ra values were determined from the 228Ac daughter activity. The method was validated by analysis of radium, thorium and uranium soil standards and by inter-comparison with other methods for radium in soils. The method allows for a rapid determination of whether a sample has been impacted by a man-made activity by comparison of the uranium and radium concentrations to those that would be expected from a natural equilibrium state.

Effect of pH and ionic strength on sorption of Eu(III) to MX-80 bentonite: batch and XAFS study

Energy Technology Data Exchange (ETDEWEB)

Sheng, G.D.; Wang, X.K. [School of Nuclear Science and Engincering, North China Electric Power Univ., BJ (China); Key Lab of Novel Thin Film Solar Cells, Inst. of Plasma Physics, Chinese Academy of Sciences, Hefei (China); Shao, D.D.; Fan, Q.H.; Xu, D. [Key Lab of Novel Thin Film Solar Cells, Inst. of Plasma Physics, Chinese Academy of Sciences, Hefei (China); Chen, Y.X. [School of Nuclear Science and Engincering, North China Electric Power Univ., BJ (China)

2009-07-01

Sorption of radionuclides on MX-80 bentonite has been studied extensively because of its high sorption capacity and low penetrability. Herein, MX-80 bentonite was characterized by acid-base titration, XRD and FTIR in detail. The sorption of Eu(III) from aqueous solution to MX-80 bentonite was investigated as a function of contact time, solid content, ionic strength and pH under N{sub 2} conditions. The experimental data was performed with the diffuse layer model (DLM) with the aid of FITEQL 3.1 code. The site densities are 2.52 x 10{sup -4} mol/g for [{identical_to}XOH] and 1.54 x 10{sup -4} mol/g for [{identical_to}YOH], and acidity constants as pK{sub a} are pK{sub XO} = 6.772, pK{sub YOH{sub 2}{sup +}} = -1.68. and pK{sub YO} = 4.145. The sorption of Eu(III) on MX-80 bentonite consists of {identical_to}YOEu{sup 2+} species at low pH values and {identical_to}XOEu(OH){sup 2+} species at high pH values. The sorption isotherms were simulated by Langmuir, Freundlich and Dubini-Radushkevich (D-R) models, respectively, and the results indicated that Langmuir model fitted the sorption data better than the Langmuir and D-R models. XAFS technique was applied to characterize the local structural environment of the adsorbed Eu(III), and the results indicated that Eu(III) was bond to O atoms at a distance of about 2.43 A as {identical_to}Y/XO-Eu{sup 2+} at low pH values. (orig.)

A Full-Duplex MAC Tailored for 5G Wireless Networks

Directory of Open Access Journals (Sweden)

Lucas de Melo Guimarães

2018-01-01

Full Text Available The increasing demands for high-data rate traffic stimulated the development of the fifth-generation (5G mobile networks. The envisioned 5G network is expected to meet its challenge by devising means to further improve spectrum usage. Many alternatives to enhance spectrum usage are being researched, such as massive MIMO, operation in mmWave frequency, cognitive radio, and the employment of full-duplex antennas. Efficient utilization of the potential of any of these technologies faces a set of challenges related to medium access control (MAC schemes. This work focuses on MAC schemes tailored for full-duplex antennas, since they are expected to play a major role in the foreseeable 5G networks. In this context, this paper presents a MAC layer technique to improve total transmission time when full-duplex antennas are employed. Several evaluations in different scenarios are conducted to assess the proposed MAC scheme. Numerical results show that the proposed scheme provides gains up to 156% when compared to a state-of-the-art full-duplex antenna MAC protocol. Compared to traditional half-duplex antenna MAC protocols, the proposed scheme yields gain up to 412%.

Electron energy spectrum in core-shell elliptic quantum wire

Directory of Open Access Journals (Sweden)

V.Holovatsky

2007-01-01

Full Text Available The electron energy spectrum in core-shell elliptic quantum wire and elliptic semiconductor nanotubes are investigated within the effective mass approximation. The solution of Schrodinger equation based on the Mathieu functions is obtained in elliptic coordinates. The dependencies of the electron size quantization spectrum on the size and shape of the core-shell nanowire and nanotube are calculated. It is shown that the ellipticity of a quantum wire leads to break of degeneration of quasiparticle energy spectrum. The dependences of the energy of odd and even electron states on the ratio between semiaxes are of a nonmonotonous character. The anticrosing effects are observed at the dependencies of electron energy spectrum on the transversal size of the core-shell nanowire.

Condensing Raman spectrum for single-cell phenotype analysis

KAUST Repository

Sun, Shiwei

2015-12-09

Background In recent years, high throughput and non-invasive Raman spectrometry technique has matured as an effective approach to identification of individual cells by species, even in complex, mixed populations. Raman profiling is an appealing optical microscopic method to achieve this. To fully utilize Raman proling for single-cell analysis, an extensive understanding of Raman spectra is necessary to answer questions such as which filtering methodologies are effective for pre-processing of Raman spectra, what strains can be distinguished by Raman spectra, and what features serve best as Raman-based biomarkers for single-cells, etc. Results In this work, we have proposed an approach called rDisc to discretize the original Raman spectrum into only a few (usually less than 20) representative peaks (Raman shifts). The approach has advantages in removing noises, and condensing the original spectrum. In particular, effective signal processing procedures were designed to eliminate noise, utilising wavelet transform denoising, baseline correction, and signal normalization. In the discretizing process, representative peaks were selected to signicantly decrease the Raman data size. More importantly, the selected peaks are chosen as suitable to serve as key biological markers to differentiate species and other cellular features. Additionally, the classication performance of discretized spectra was found to be comparable to full spectrum having more than 1000 Raman shifts. Overall, the discretized spectrum needs about 5storage space of a full spectrum and the processing speed is considerably faster. This makes rDisc clearly superior to other methods for single-cell classication.

Integrability for the full spectrum of planar AdS/CFT

International Nuclear Information System (INIS)

Gromov, Nikolay; Kazakov, Vladimir; Vieira, Pedro; Porto Univ.

2009-03-01

We present a set of functional equations defining the anomalous dimensions of arbitrary local single trace operators in planar N=4 SYM theory. It takes the form of a Y-system based on the integrability of the dual superstring σ-model on the AdS 5 x S 5 background. This Y-system passes some very important tests: it incorporates the full asymptotic Bethe ansatz at large length of operator L, including the dressing factor, and it confirms all recently found wrapping corrections. The recently proposed AdS 4 /CFT 3 duality is also treated in a similar fashion. (orig.)

Speech spectrum's correlation with speakers' Eysenck personality traits.

Directory of Open Access Journals (Sweden)

Chao Hu

Full Text Available The current study explored the correlation between speakers' Eysenck personality traits and speech spectrum parameters. Forty-six subjects completed the Eysenck Personality Questionnaire. They were instructed to verbally answer the questions shown on a computer screen and their responses were recorded by the computer. Spectrum parameters of /sh/ and /i/ were analyzed by Praat voice software. Formant frequencies of the consonant /sh/ in lying responses were significantly lower than that in truthful responses, whereas no difference existed on the vowel /i/ speech spectrum. The second formant bandwidth of the consonant /sh/ speech spectrum was significantly correlated with the personality traits of Psychoticism, Extraversion, and Neuroticism, and the correlation differed between truthful and lying responses, whereas the first formant frequency of the vowel /i/ speech spectrum was negatively correlated with Neuroticism in both response types. The results suggest that personality characteristics may be conveyed through the human voice, although the extent to which these effects are due to physiological differences in the organs associated with speech or to a general Pygmalion effect is yet unknown.

Fast radio burst search: cross spectrum vs. auto spectrum method

Science.gov (United States)

Liu, Lei; Zheng, Weimin; Yan, Zhen; Zhang, Juan

2018-06-01

The search for fast radio bursts (FRBs) is a hot topic in current radio astronomy studies. In this work, we carry out a single pulse search with a very long baseline interferometry (VLBI) pulsar observation data set using both auto spectrum and cross spectrum search methods. The cross spectrum method, first proposed in Liu et al., maximizes the signal power by fully utilizing the fringe phase information of the baseline cross spectrum. The auto spectrum search method is based on the popular pulsar software package PRESTO, which extracts single pulses from the auto spectrum of each station. According to our comparison, the cross spectrum method is able to enhance the signal power and therefore extract single pulses from data contaminated by high levels of radio frequency interference (RFI), which makes it possible to carry out a search for FRBs in regular VLBI observations when RFI is present.

Inertial-range spectrum of whistler turbulence

Directory of Open Access Journals (Sweden)

Y. Narita

2010-02-01

Full Text Available We develop a theoretical model of an inertial-range energy spectrum for homogeneous whistler turbulence. The theory is a generalization of the Iroshnikov-Kraichnan concept of the inertial-range magnetohydrodynamic turbulence. In the model the dispersion relation is used to derive scaling laws for whistler waves at highly oblique propagation with respect to the mean magnetic field. The model predicts an energy spectrum for such whistler waves with a spectral index −2.5 in the perpendicular component of the wave vector and thus provides an interpretation about recent discoveries of the second inertial-range of magnetic energy spectra at high frequencies in the solar wind.

Incidence of Traumatic Brain Injury Across the Full Disease Spectrum: A Population-Based Medical Record Review Study

Science.gov (United States)

Leibson, Cynthia L.; Brown, Allen W.; Ransom, Jeanine E.; Diehl, Nancy N.; Perkins, Patricia K.; Mandrekar, Jay; Malec, James F.

2012-01-01

Background Extremely few objective estimates of traumatic brain injury incidence include all ages, both sexes, all injury mechanisms, and the full spectrum from very mild to fatal events. Methods We used unique Rochester Epidemiology Project medical records-linkage resources, including highly sensitive and specific diagnostic coding, to identify all Olmsted County, MN, residents with diagnoses suggestive of traumatic brain injury regardless of age, setting, insurance, or injury mechanism. Provider-linked medical records for a 16% random sample were reviewed for confirmation as definite, probable, possible (symptomatic), or no traumatic brain injury. We estimated incidence per 100,000 person-years for 1987–2000 and compared these record-review rates with rates obtained using Centers for Disease Control and Prevention (CDC) data-systems approach. For the latter, we identified all Olmsted County residents with any CDC-specified diagnosis codes recorded on hospital/emergency department administrative claims or death certificates 1987–2000. Results Of sampled individuals, 1257 met record-review criteria for incident traumatic brain injury; 56% were ages 16–64 years, 56% were male, 53% were symptomatic. Mechanism, sex, and diagnostic certainty differed by age. The incidence rate per 100,000 person-years was 558 (95% confidence interval = 528–590) versus 341 (331–350) using the CDC data system approach. The CDC approach captured only 40% of record-review cases. Seventy-four percent of missing cases presented to hospital/emergency department; none had CDC-specified codes assigned on hospital/emergency department administrative claims or death certificates; 66% were symptomatic. Conclusions Capture of symptomatic traumatic brain injuries requires a wider range of diagnosis codes, plus sampling strategies to avoid high rates of false-positive events. PMID:21968774

Full-wave Simulation of Doppler Reflectometry in the Presence of Turbulence

Energy Technology Data Exchange (ETDEWEB)

Lechte, C. [Institut fur Plasmaforschung, Universitat Stuttgart, Stuttgart (Germany)

2011-07-01

Doppler reflectometry is a microwave plasma diagnostic well suited for density fluctuation measurement. A meaningful interpretation of Doppler reflectometry measurements necessitates the analysis of the wave propagation in the plasma using simulations methods. While the beam path can usually be reconstructed with beam tracing methods, the modeling of the scattering process demands the use of wave simulation codes. Furthermore, in the presence of strong density fluctuations, the response from the plasma is dominated by dispersion and multiple scattering, and hence becomes non-linear. IPF-FD3D is the finite difference time domain code used to investigate the dependence of the scattering efficiency on the various plasma conditions. It uses the full set of Maxwell equations and the electron equation of motion in a cold plasma. First results in slab geometry indicate a strong dependence of the scattering efficiency on the density gradient, the incident angle, and the wave polarisation. Further complications arise with the introduction of broadband turbulent fluctuations, where additional knowledge of the radial spectrum is necessary to reconstruct the full fluctuation spectrum from Doppler reflectometry measurements. This paper presents the reconstruction of the turbulent fluctuation spectrum from simulated Doppler reflectometry measurements in slab geometry. Two cases of analytical turbulence in slab geometry are presented where the fluctuation wavenumber spectrum was recovered. It is planned to extend these investigations to X mode polarization and to supplement actual fusion experiments

The action spectrum in chloroplast translocation in multilayer leaf cells

Directory of Open Access Journals (Sweden)

Zbigniew Lechowski

2015-01-01

Full Text Available By measurement of light transmittance through a leaf as criterion of chloroplast translocation, the action spectrum of Ajuga reptans was established. In the spectrum obtained, a correction was introduced for leaf autoabsorption calculated on the basis of the Beer-Lambert law. The action spectrum has two maxima: at λ= 375 nm and λ= 481 nm. The range above 502 nm has no significant effect on chloroplast translocation. Comparison with other objects examined demonstrated that in multilayer leaf cells riboflavin seems also to be a photoreceptor active in this process.

Was The Electromagnetic Spectrum A Blackbody Spectrum In The Early Universe?

OpenAIRE

Opher, Merav; Opher, Reuven

1997-01-01

It is assumed, in general, that the electromagnetic spectrum in the Primordial Universe was a blackbody spectrum in vacuum. We derive the electromagnetic spectrum, based on the Fluctuation-Dissipation Theorem that describes the electromagnetic fluctuations in a plasma. Our description includes thermal and collisional effects in a plasma. The electromagnetic spectrum obtained differs from the blackbody spectrum in vacuum at low frequencies. In particular, concentrating on the primordial nucleo...

Real-Time Amplitude and Phase Imaging of Optically Opaque Objects by Combining Full-Field Off-Axis Terahertz Digital Holography with Angular Spectrum Reconstruction

Science.gov (United States)

Yamagiwa, Masatomo; Ogawa, Takayuki; Minamikawa, Takeo; Abdelsalam, Dahi Ghareab; Okabe, Kyosuke; Tsurumachi, Noriaki; Mizutani, Yasuhiro; Iwata, Testuo; Yamamoto, Hirotsugu; Yasui, Takeshi

2018-06-01

Terahertz digital holography (THz-DH) has the potential to be used for non-destructive inspection of visibly opaque soft materials due to its good immunity to optical scattering and absorption. Although previous research on full-field off-axis THz-DH has usually been performed using Fresnel diffraction reconstruction, its minimum reconstruction distance occasionally prevents a sample from being placed near a THz imager to increase the signal-to-noise ratio in the hologram. In this article, we apply the angular spectrum method (ASM) for wavefront reconstruction in full-filed off-axis THz-DH because ASM is more accurate at short reconstruction distances. We demonstrate real-time phase imaging of a visibly opaque plastic sample with a phase resolution power of λ/49 at a frame rate of 3.5 Hz in addition to real-time amplitude imaging. We also perform digital focusing of the amplitude image for the same object with a depth selectivity of 447 μm. Furthermore, 3D imaging of visibly opaque silicon objects was achieved with a depth precision of 1.7 μm. The demonstrated results indicate the high potential of the proposed method for in-line or in-process non-destructive inspection of soft materials.

Real-Time Amplitude and Phase Imaging of Optically Opaque Objects by Combining Full-Field Off-Axis Terahertz Digital Holography with Angular Spectrum Reconstruction

Science.gov (United States)

Yamagiwa, Masatomo; Ogawa, Takayuki; Minamikawa, Takeo; Abdelsalam, Dahi Ghareab; Okabe, Kyosuke; Tsurumachi, Noriaki; Mizutani, Yasuhiro; Iwata, Testuo; Yamamoto, Hirotsugu; Yasui, Takeshi

2018-04-01

Terahertz digital holography (THz-DH) has the potential to be used for non-destructive inspection of visibly opaque soft materials due to its good immunity to optical scattering and absorption. Although previous research on full-field off-axis THz-DH has usually been performed using Fresnel diffraction reconstruction, its minimum reconstruction distance occasionally prevents a sample from being placed near a THz imager to increase the signal-to-noise ratio in the hologram. In this article, we apply the angular spectrum method (ASM) for wavefront reconstruction in full-filed off-axis THz-DH because ASM is more accurate at short reconstruction distances. We demonstrate real-time phase imaging of a visibly opaque plastic sample with a phase resolution power of λ/49 at a frame rate of 3.5 Hz in addition to real-time amplitude imaging. We also perform digital focusing of the amplitude image for the same object with a depth selectivity of 447 μm. Furthermore, 3D imaging of visibly opaque silicon objects was achieved with a depth precision of 1.7 μm. The demonstrated results indicate the high potential of the proposed method for in-line or in-process non-destructive inspection of soft materials.

Quantifying creativity: can measures span the spectrum?

Science.gov (United States)

Simonton, Dean Keith

2012-03-01

Because the cognitive neuroscientists have become increasingly interested in the phenomenon of creativity, the issue arises of how creativity is to be optimally measured. Unlike intelligence, which can be assessed across the full range of intellectual ability creativity measures tend to concentrate on different sections of the overall spectrum. After first defining creativity in terms of the three criteria of novelty, usefulness, and surprise, this article provides an overview of the available measures. Not only do these instruments vary according to whether they focus on the creative process, person, or product, but they differ regarding whether they tap into "little-c" versus "Big-C" creativity; only productivity and eminence measures reach into genius-level manifestations of the phenomenon. The article closes by discussing whether various alternative assessment techniques can be integrated into a single measure that quantifies creativity across the full spectrum.

Was The Electromagnetic Spectrum A Blackbody Spectrum In The Early Universe?

International Nuclear Information System (INIS)

Opher, M.; Opher, R.

1997-01-01

It is generally assumed that the electromagnetic spectrum in the primordial universe was a blackbody spectrum in vacuum. We derive the electromagnetic spectrum based on the fluctuation-dissipation theorem that describes the electromagnetic fluctuations in a plasma. Our description includes thermal and collisional effects in a plasma. The electromagnetic spectrum obtained differs from a blackbody spectrum in vacuum at low frequencies. In particular, concentrating on the primordial nucleosynthesis era, it has more energy than the blackbody spectrum for frequencies less than 3ω pe to 6ω pe , where ω pe is the electron plasma frequency. copyright 1997 The American Physical Society

Xyloglucan endotransglucosylase/hydrolases (XTHs) are inactivated by binding to glass and cellulosic surfaces, and released in active form by a heat-stable polymer from cauliflower florets.

Science.gov (United States)

Sharples, Sandra C; Nguyen-Phan, Tu C; Fry, Stephen C

2017-11-01

Xyloglucan endotransglucosylase (XET) activity, which cuts and re-joins hemicellulose chains in the plant cell wall, contributing to wall assembly and growth regulation, is the major activity of XTH proteins. During purification, XTHs often lose XET activity which, however, is restored by treatment with certain cold-water-extractable, heat-stable polymers (CHPs), e.g. from cauliflower florets. It was not known whether the XTH-activating factor (XAF) present in CHPs works by promoting (e.g. allosterically) XET activity or by re-solubilising sequestered XTH proteins. We now show that XTHs in dilute solution bind to diverse surfaces (e.g. glass and cellulose), and that CHPs can re-solubilise the bound enzyme, re-activating it. Cell walls prepared from cauliflower florets, mung bean shoots and Arabidopsis cell-suspension cultures each contained endogenous, tightly bound, inactive XTHs, which were likewise rapidly solubilised (within 0.5h) and thus activated by cauliflower XAF. We present a convenient quantitative assay for XAF acting on the native sequestered XTHs of Arabidopsis cell walls; using this assay, we show that CHPs from all plants tested possess XAF activity. The XAF activity of diverse CHPs does not correlate with their conductivity, showing that this activity is not a simple ionic effect. The XAF action of cauliflower CHPs was augmented by NaCl, although NaCl alone was much less effective than a CHP solution of similar conductivity, confirming that the cauliflower polymers did not simply exert a salt effect. We suggest that XAF is an endogenous regulator of XET action, modulating cell-wall loosening and/or assembly in vivo. Copyright © 2017 The Authors. Published by Elsevier GmbH.. All rights reserved.

Energy and spectrum efficiency in rural areas based on cognitive radio technology

CSIR Research Space (South Africa)

Masonta, MT

2009-09-01

Full Text Available spectrum scarcity in the most energy efficient manner. In this paper, researchers present the proposed work to be carried out as part of a doctoral thesis to address the spectrum scarcity and transmission power in energy constrained rural areas....

Multiple Beta Spectrum Analysis Method Based on Spectrum Fitting

Energy Technology Data Exchange (ETDEWEB)

Lee, Uk Jae; Jung, Yun Song; Kim, Hee Reyoung [UNIST, Ulsan (Korea, Republic of)

2016-05-15

When the sample of several mixed radioactive nuclides is measured, it is difficult to divide each nuclide due to the overlapping of spectrums. For this reason, simple mathematical analysis method for spectrum analysis of the mixed beta ray source has been studied. However, existing research was in need of more accurate spectral analysis method as it has a problem of accuracy. The study will describe the contents of the separation methods of the mixed beta ray source through the analysis of the beta spectrum slope based on the curve fitting to resolve the existing problem. The fitting methods including It was understood that sum of sine fitting method was the best one of such proposed methods as Fourier, polynomial, Gaussian and sum of sine to obtain equation for distribution of mixed beta spectrum. It was shown to be the most appropriate for the analysis of the spectrum with various ratios of mixed nuclides. It was thought that this method could be applied to rapid spectrum analysis of the mixed beta ray source.

Clinical Manifestations of Self-disorders in Schizophrenia Spectrum Conditions

Directory of Open Access Journals (Sweden)

Henriksen Mads Gram

2017-09-01

Full Text Available This article explores the phenomenologically informed, theoretical and empirical research direction on self-disorders in the schizophrenia spectrum conditions. First, we describe the concept of ‘self’ that is operative in the concept of ‘self-disorders’ and we discuss how this self may be disordered or fragile in the schizophrenia spectrum. Second, we offer a detailed psychopathological presentation and discussion of 3 patients with schizophrenia. The vignettes provide paradigmatic examples of self-disorders in schizophrenia. Third, we summarize the main findings in the current empirical research on self-disorders. These findings consistently indicate that self-disorders constitute a crucial, trait phenotype of the schizophrenia spectrum.

Scaling model for a speed-dependent vehicle noise spectrum

Directory of Open Access Journals (Sweden)

Giovanni Zambon

2017-06-01

Full Text Available Considering the well-known features of the noise emitted by moving sources, a number of vehicle characteristics such as speed, unladen mass, engine size, year of registration, power and fuel were recorded in a dedicated monitoring campaign performed in three different places, each characterized by different number of lanes and the presence of nearby reflective surfaces. A full database of 144 vehicles (cars was used to identify statistically relevant features. In order to compare the vehicle transit noise in different environmental condition, all 1/3-octave band spectra were normalized and analysed. Unsupervised clustering algorithms were employed to group together spectrum levels with similar profiles. Our results corroborate the well-known fact that speed is the most relevant characteristic to discriminate between different vehicle noise spectrum. In keeping with this fact, we present a new approach to predict analytically noise spectra for a given vehicle speed. A set of speed-dependent analytical functions are suggested in order to fit the normalized average spectrum profile at different speeds. This approach can be useful for predicting vehicle speed based purely on its noise spectrum pattern. The present work is complementary to the accurate analysis of noise sources based on the beamforming technique.

Spectrum of teaching styles in the Czech Republic

Directory of Open Access Journals (Sweden)

Jana Šafaříková

2016-02-01

Full Text Available The AIESEP International Conference, June 9–12, 2016, sponsored by the University of Wyoming in Laramie, will celebrate the 50th anniversary of the “Spectrum of Teaching Styles”. Although this pedagogical theory was first published in 1966 by Muska Mosston, it has continuously influenced and internationally contributed to the field of Physical Education. The 50th anniversary celebration is an appropriate occasion to briefly acknowledge the history of the Spectrum’s international journey. The following historical account acknowledges the introduction and influence of the Spectrum in the former Czechoslovakia, beginning in 1971 and continuing into the Czech Republic era. The first section of this article acknowledges the contributions of the Spectrum and its international acceptance. The second section focuses on Prague and the active role of the many scholars who studied, implemented, and researched the Spectrum. The third section presents some teaching style research results conducted by Faculty of Physical Education and Sport, Charles University (UK FTVS.

Distance spectrum of Indu–Bala product of graphs

Directory of Open Access Journals (Sweden)

G. Indulal

2016-12-01

Full Text Available The D-eigenvalues μ1,μ2,…,μn of a graph G of order n are the eigenvalues of its distance matrix D and form the distance spectrum or D-spectrum of G denoted by SpecD(G. Let G1 and G2 be two regular graphs. The Indu–Bala product of G1 and G2 is denoted by G1▾G2 and is obtained from two disjoint copies of the join G1∨G2 of G1 and G2 by joining the corresponding vertices in the two copies of G2. In this paper we obtain the distance spectrum of G1▾G2 in terms of the adjacency spectra of G1 and G2. We use this result to obtain a new class of distance equienergetic graphs of diameter 3. We also prove that the class of graphs Kn¯▾Kn+1¯ has integral distance spectrum.

Analysis of biological spectrum of Divčibare flora

Directory of Open Access Journals (Sweden)

Popović Ivana

2006-01-01

Full Text Available One of the essential analyses which is performed during the floristic study of a region is the analysis of the biological spectrum. The analysis of the biological spectrum of the flora includes the determination of the type of life form for each taxon described in the flora of the study region. If it is considered that life form is a specific structural-functional response to the environmental effects and the result of the adaptation during the species evolution, it is clear that the basic characteristics of the site are more or less reflected in any life form. This fact is confirmed by the analysis of the biological spectrum of Divčibare flora. The study results are in correlation with the results of the analysis of the biological spectrum of the flora of Serbia and the Balkan Peninsula.

ADAPTIVE FULL-SPECTRUM SOLAR ENERGY SYSTEMS CROSS-CUTTING R&D ON ADAPTIVE FULL-SPECTRUM SOLAR ENERGY SYSTEMS FOR MORE EFFICIENT AND AFFORDABLE USE OF SOLAR ENERGY IN BUILDINGS AND HYBRID PHOTOBIOREACTORS

Energy Technology Data Exchange (ETDEWEB)

Byard D. Wood; Jeff D. Muhs

2004-08-01

This RD&D project is a three year team effort to develop a hybrid solar lighting (HSL) system that transports daylight from a paraboloidal dish concentrator to a luminaire via a bundle of small core or a large core polymer fiber optics. The luminaire can be a device to distribute sunlight into a space for the production of algae or it can be a device that is a combination of daylighting and electric lighting for space/task lighting. In this project, the sunlight is collected using a one-meter paraboloidal concentrator dish with two-axis tracking. For the second generation (alpha) system, the secondary mirror is an ellipsoidal mirror that directs the visible light into a bundle of small-core fibers. The IR spectrum is filtered out to minimize unnecessary heating at the fiber entrance region. This report describes the following investigations of various aspects of the system. Taken as a whole, they confirm significant progress towards the technical feasibility and commercial viability of this technology. (1) TRNSYS Modeling of a Hybrid Lighting System: Building Energy Loads and Chromaticity Analysis; (2) High Lumens Screening Test Setup for Optical Fibers; (3) Photo-Induced Heating in Plastic Optical Fiber Bundles; (4) Low-Cost Primary Mirror Development; (5) Potential Applications for Hybrid Solar Lighting; (6) Photobioreactor Population Experiments and Productivity Measurements; and (7) Development of a Microalgal CO2-Biofixation Photobioreactor.

PERFORMANCE OPTIMIZATION OF COGNITIVE RADIO WITH WIDEBAND SPECTRUM SENSING

Directory of Open Access Journals (Sweden)

E. Saraniya

2014-09-01

Full Text Available Cognitive radio (CR technology allows the unlicensed user to access the licensed spectrum bands. Spectrum sensing is an essential function in cognitive radio to detect the spectrum holes and opportunistically use the underutilized frequency bands without causing interference to primary user (PU. In this paper we are maximizing the throughput capacity of cognitive radio user and hence the performance of spectrum sensing and protection to licensed user improves over a wideband spectrum sensing band. The simulation of cognitive radio is done by analyzing the performance of energy detector spectrum sensing technique to detect primary user and to formulate the optimization using multiband joint detection method (MJD to achieve suitable trade- off between secondary user access and primary user network. The main aim of this paper is to maximize the probability of detection and to decrease the probabilities of miss detection and false alarm. To maximize the throughput it requires minimizing the throughput loss caused by miss detection and the significant reduction in probability of false alarm helps in achieving the spectral efficiency from the secondary user’s perspective. The simulation results show that the performance increases with the MJD method.

Spectrum access games for cognitive radio networks

CSIR Research Space (South Africa)

Masonta, MT

2010-09-01

Full Text Available received a wide acceptance in next generation and intelligent wireless communication systems. In this paper the authors make use of game theory approach to model and analyze cognitive radio networks in order to allow dynamic spectrum access in broadband...

Comparison of RF spectrum prediction methods for dynamic spectrum access

Science.gov (United States)

Kovarskiy, Jacob A.; Martone, Anthony F.; Gallagher, Kyle A.; Sherbondy, Kelly D.; Narayanan, Ram M.

2017-05-01

Dynamic spectrum access (DSA) refers to the adaptive utilization of today's busy electromagnetic spectrum. Cognitive radio/radar technologies require DSA to intelligently transmit and receive information in changing environments. Predicting radio frequency (RF) activity reduces sensing time and energy consumption for identifying usable spectrum. Typical spectrum prediction methods involve modeling spectral statistics with Hidden Markov Models (HMM) or various neural network structures. HMMs describe the time-varying state probabilities of Markov processes as a dynamic Bayesian network. Neural Networks model biological brain neuron connections to perform a wide range of complex and often non-linear computations. This work compares HMM, Multilayer Perceptron (MLP), and Recurrent Neural Network (RNN) algorithms and their ability to perform RF channel state prediction. Monte Carlo simulations on both measured and simulated spectrum data evaluate the performance of these algorithms. Generalizing spectrum occupancy as an alternating renewal process allows Poisson random variables to generate simulated data while energy detection determines the occupancy state of measured RF spectrum data for testing. The results suggest that neural networks achieve better prediction accuracy and prove more adaptable to changing spectral statistics than HMMs given sufficient training data.

Analysis of a gamma-ray spectrum by using a standard spectrum

International Nuclear Information System (INIS)

Tasaka, Kanji

1975-06-01

The standard spectrum method has been extended to take into account the energy dependence of a standard spectrum. The method analyses the observed gamma-ray spectrum by the least-square method, using an interpolated standard spectrum for expressing the line shape and a linear function for the background continuum. The interpolated standard spectrum is defined for each fitting interval by interpolating several standard spectra, which are derived directly from the observed spectra of single photopeaks each corresponding to the incident monochromatic gamma-rays by subtracting the background and smoothing the data. (author)

Framework for TV white space spectrum access in Southern African Development Community (SADC)

CSIR Research Space (South Africa)

Masonta, MT

2013-09-01

Full Text Available The global migration of television (TV) from analogue to digital broadcast will see a large amount of TV spectrum available (called TV white space - TVWS) for other services such as mobile and broadband wireless access (BWA). Leading spectrum...

PROVIDING DENTAL CARE FOR CHILDREN WITH AUTISM SPECTRUM DISORDERS

Directory of Open Access Journals (Sweden)

Diana MURARU

2017-06-01

Full Text Available Given the increasing prevalence of autism spectrum disorders, it is realistic to assume that dental professionals are likely to treat individuals with this diagnosis. Understanding the complexities of this disorder and its behavioral manifestations is indispensable for dentists. The present article presents several characteristics of autism spectrum disorder that impact dental interventions, along with medical and behavioral alternatives to better manage the dental problems of children with autism spectrum disorder. A multidisciplinary approach and family support are important for planning a dental intervention for these patients in order to avoid anxiety. Knowledge on autism, the dentist-patient relationship and the individual preparation for dental interventions is useful for constructing a controllable medical experience

Probing dark energy using convergence power spectrum and bi-spectrum

Energy Technology Data Exchange (ETDEWEB)

Dinda, Bikash R., E-mail: bikash@ctp-jamia.res.in [Centre for Theoretical Physics, Jamia Millia Islamia, New Delhi-110025 (India)

2017-09-01

Weak lensing convergence statistics is a powerful tool to probe dark energy. Dark energy plays an important role to the structure formation and the effects can be detected through the convergence power spectrum, bi-spectrum etc. One of the most promising and simplest dark energy model is the ΛCDM . However, it is worth investigating different dark energy models with evolving equation of state of the dark energy. In this work, detectability of different dark energy models from ΛCDM model has been explored through convergence power spectrum and bi-spectrum.

Autism Spectrum Disorders and Schizophrenia Spectrum Disorders: Excitation/Inhibition Imbalance and Developmental Trajectories

Directory of Open Access Journals (Sweden)

Roberto Canitano

2017-05-01

Full Text Available Autism spectrum disorders (ASD and schizophrenia spectrum disorders (SSD share clinical and genetic components that have long been recognized. The two disorders co-occur more frequently than would be predicted by their respective prevalence, suggesting that a complex, multifactor association is involved. However, DSM-5 maintains the distinction between ASD, with core social and communication impairments, and SSD, including schizophrenia (SCZ, with hallucinations, delusions, and thought disorder as essential features. ASD and SSD have common biological underpinnings that may emerge early in development and unfold over time. One of the hypotheses supporting the similarities in the social and cognitive disturbances of ASD and SSD relates to abnormalities in the ratio of excitatory to inhibitory cortical activity (E/I imbalance. E/I imbalance in neurodevelopmental disorders could be the consequence of abnormalities in genes coding for glutamatergic and GABAergic receptors or synaptic proteins followed by system derangements. SSD and ASD have been characterized as polygenic disorders in which to the onset and progression of disease is triggered by interactions among multiple genes. Mammalian target of rapamycin signaling is under intense investigation as a convergent altered pathway in the two spectrum disorders. Current understanding of shared and divergent patterns between ASD and SSD from molecular to clinical aspects is still incomplete and may be implemented by the research domain criteria approach.

Four-Tap RF Canceller Evaluation for Indoor In-Band Full-Duplex Wireless Operation

Science.gov (United States)

2016-07-24

I. INTRODUCTION In-band full-duplex (IBFD) wireless operation can help alleviate the frequency spectrum congestion issues faced by current system...Valkama, “Wideband self-adaptive rf cancellation circuit for full- duplex radio: Operating principle and measurements,” in 2015 IEEE 81st Vehicular

ADAPTIVE FULL-SPECTRUM SOLAR ENERGY SYSTEMS CROSS-CUTTING R&D ON ADAPTIVE FULL-SPECTRUM SOLAR ENERGY SYSTEMS FOR MORE EFFICIENT AND AFFORDABLE USE OF SOLAR ENERGY IN BUILDINGS AND HYBRID PHOTOBIOREACTORS

Energy Technology Data Exchange (ETDEWEB)

Byard D. Wood; Jeff D. Muhs

2005-02-01

This RD&D project is a three year team effort to develop a hybrid solar lighting (HSL) system that transports daylight from a paraboloidal dish concentrator to a luminaire via a bundle of small core or a large core polymer fiber optics. The luminaire can be a device to distribute sunlight into a space for the production of algae or it can be a device that is a combination of daylighting and electric lighting for space/task lighting. In this project, the sunlight is collected using a one-meter paraboloidal concentrator dish with two-axis tracking. For the second generation (alpha) system, the secondary mirror is an ellipsoidal mirror that directs the visible light into a bundle of small-core fibers. The IR spectrum is filtered out to minimize unnecessary heating at the fiber entrance region. This report describes the following investigations of various aspects of the system: (1) Performance specifications were developed for the tracking subsystem and collector optics, (2) Thermal management experiments for the fiber optic bundle entrance region, and (3) Bioreactor testing, cost-modeling, and redesign. Much of the planned work has been slowed due to significant procurement delays of the primary mirror. However, taken as a whole, they do confirm progress towards the technical feasibility and commercial viability of this technology. Due to this procurement delay, a no-cost extension of the project completion date has been requested and approved.

Influence of near-edge processes in the elemental analysis using X

Indian Academy of Sciences (India)

The near-edge processes, such as X-ray absorption fine structure (XAFS) andresonant ... away from the shell/subshell ionization thresholds of the attenuator element. ... The influence of XAFS to the attenuation coefficient depends upon the ...

Korean Culture and Autism Spectrum Disorders

Science.gov (United States)

Kang-Yi, Christina D.; Grinker, Roy R.; Mandell, David S.

2013-01-01

This paper reviews the literature on early child development among Koreans, with a focus on autism spectrum disorders (ASD). The literature review of 951 abstracts in English, 101 abstracts in Korean and 27 full articles published from 1994 to 2011 was performed to understand the presentation of and response to ASD in Korean culture. Based on…

[Study on the method for the determination of trace boron, molybdenum, silver, tin and lead in geochemical samples by direct current arc full spectrum direct reading atomic emission spectroscopy (DC-Arc-AES)].

Science.gov (United States)

Hao, Zhi-hong; Yao, Jian-zhen; Tang, Rui-ling; Zhang, Xue-mei; Li, Wen-ge; Zhang, Qin

2015-02-01

The method for the determmation of trace boron, molybdenum, silver, tin and lead in geochemical samples by direct current are full spectrum direct reading atomic emission spectroscopy (DC-Arc-AES) was established. Direct current are full spectrum direct reading atomic emission spectrometer with a large area of solid-state detectors has functions of full spectrum direct reading and real-time background correction. The new electrodes and new buffer recipe were proposed in this paper, and have applied for national patent. Suitable analytical line pairs, back ground correcting points of elements and the internal standard method were selected, and Ge was used as internal standard. Multistage currents were selected in the research on current program, and each current set different holding time to ensure that each element has a good signal to noise ratio. Continuous rising current mode selected can effectively eliminate the splash of the sample. Argon as shielding gas can eliminate CN band generating and reduce spectral background, also plays a role in stabilizing the are, and argon flow 3.5 L x min(-1) was selected. Evaporation curve of each element was made, and it was concluded that the evaporation behavior of each element is consistent, and combined with the effects of different spectrographic times on the intensity and background, the spectrographic time of 35s was selected. In this paper, national standards substances were selected as a standard series, and the standard series includes different nature and different content of standard substances which meet the determination of trace boron, molybdenum, silver, tin and lead in geochemical samples. In the optimum experimental conditions, the detection limits for B, Mo, Ag, Sn and Pb are 1.1, 0.09, 0.01, 0.41, and 0.56 microg x g(-1) respectively, and the precisions (RSD, n=12) for B, Mo, Ag, Sn and Pb are 4.57%-7.63%, 5.14%-7.75%, 5.48%-12.30%, 3.97%-10.46%, and 4.26%-9.21% respectively. The analytical accuracy was

On the passivation mechanism of Fe{sub 3}O{sub 4} nanoparticles during Cr(VI) removal from water: A XAFS study

Energy Technology Data Exchange (ETDEWEB)

Pinakidou, F., E-mail: fpina@physics.auth.gr [Aristotle University of Thessaloniki, Department of Chemical Engineering, Analytical Chemistry Laboratory, 54124 Thessaloniki (Greece); Katsikini, M. [Aristotle University of Thessaloniki, School of Physics, Section of Solid State Physics, 54124 Thessaloniki (Greece); Simeonidis, K.; Kaprara, E. [Aristotle University of Thessaloniki, Department of Chemical Engineering, Analytical Chemistry Laboratory, 54124 Thessaloniki (Greece); Paloura, E.C. [Aristotle University of Thessaloniki, School of Physics, Section of Solid State Physics, 54124 Thessaloniki (Greece); Mitrakas, M. [Aristotle University of Thessaloniki, Department of Chemical Engineering, Analytical Chemistry Laboratory, 54124 Thessaloniki (Greece)

2016-01-01

Graphical abstract: - Highlights: • Presence of Fe(II) even after high Cr-loading. • The vacancies in the γ-Fe{sub 2}O{sub 3} layer formed offer sites for Cr(III) sorption. • Cr(III) sorbs into the vacancies and Cr(VI) forms outer sphere complexes. • Increasing surface Cr(III) loading changes the polymerization of the Fe–O–Fe chains. • Cr(III) sorption modifies Fe{sub 3}O{sub 4} structure obstructing further Cr(VI) removal. - Abstract: X-Ray Absorption Spectroscopies (XAFS) are employed in order to gather a thorough insight on the uptake mechanism of Cr(VI) by Fe{sub 3}O{sub 4} nanoparticles under water treatment conditions. The XANES measurements identify that the reducing potential of Fe{sub 3}O{sub 4} activates the precipitation of Cr(VI) in the form of insoluble and non-toxic Cr(III). However, electron donation from Fe(II) is responsible for its gradual consumption, resulting in the presence of a surface maghemite layer and the formation of structural vacancies. EXAFS analysis reveal that adsorption of Cr(III)-oxyanions occurs on sorption sites provided by the vacancies in the maghemite layer, where Cr(III) is involved in a bidentate binuclear ({sup 2}E) geometry with Fe-octahedra while it also forms monodentate ({sup 1}V) complexes with the Fe(III)O{sub 4} tetrahedra. The surface maghemitization along with the reduced Cr(III) adsorption into the vacancies, tracks the degree of Cr-reduction, since this surface structural modifications hinder Cr(VI) access to the Fe(II) ions of the magnetite nanoparticles. Thus, high surface coverage leads to the passivation of the reduction ability since physisorbed Cr(VI) is also detected through the formation of outer sphere complexes.

Memory, learning and language in autism spectrum disorder

Directory of Open Access Journals (Sweden)

Jill Boucher

2018-02-01

Full Text Available Background and aims The ‘dual-systems’ model of language acquisition has been used by Ullman et al. to explain patterns of strength and weakness in the language of higher-functioning people with autism spectrum disorder. Specifically, intact declarative/explicit learning is argued to compensate for a deficit in non-declarative/implicit procedural learning, constituting an example of the so-called see-saw effect. Ullman and Pullman extended their argument concerning a see-saw effect on language in autism spectrum disorder to cover other perceived anomalies of behaviour, including impaired acquisition of social skills. The aim of this paper is to present a critique of Ullman et al.’s claims and to propose an alternative model of links between memory systems and language in autism spectrum disorder. Main contribution We argue that a four-system model of learning, in which intact semantic and procedural memory are used to compensate for weaknesses in episodic memory and perceptual learning, can better explain patterns of language ability across the autistic spectrum. We also argue that attempts to generalise the ‘impaired implicit learning/spared declarative learning’ theory to other behaviours in autism spectrum disorder are unsustainable. Conclusions Clinically significant language impairments in autism spectrum disorder are under-researched, despite their impact on everyday functioning and quality of life. The relative paucity of research findings in this area lays it open to speculative interpretation which may be misleading. Implications More research is needed into links between memory/learning systems and language impairments across the spectrum. Improved understanding should inform therapeutic intervention and contribute to investigation of the causes of language impairment in autism spectrum disorder with potential implications for prevention.

Application of real time spectrum measurement to radiation monitors

International Nuclear Information System (INIS)

Matsuno, K.; Watanabe, M.; Sakamaki, T.

1996-01-01

A multichannel analyzer (MCA) and two realtime spectrum monitoring methods have been developed for use in radiation monitors. The new MCA was designed to be installed at a local site as a component of a radiation monitor. The MCA repeats spectrum measurement at short intervals (Δt) and, after each measurement, transmits a spectrum datum to the operation console. The authors applied two methods to process Δt spectrum counts for each channel for longer time interval. One method of processing counts is the 'running average (RA) method'. The other method is the 'exponential smoothing (ES) method', which simulates RC rate meters by subtracting a fraction corresponding to the accumulated counts. Relative standard deviations for each channel can be made the same by selecting an appropriate value. The response with the 'ES' method is initially faster than that with the 'RA' method, but the 'RA' method allows a full response to be reached at a predictable time. (author)

VHF spectrum monitoring using Meraka cognitive radio platform

CSIR Research Space (South Africa)

Aderonmu, AI

2012-11-01

Full Text Available discuss the Meraka Cognitive Radio Platform (MCRP) developed using the second version of the Universal Serial Radio Peripheral (USRP2) hardware and the GNU Radio software. We also discussed how the spectrum monitoring system is being implemented...

The Spectrum Sharing in Cognitive Radio Networks Based on Competitive Price Game

Directory of Open Access Journals (Sweden)

Y. B. Li

2012-09-01

Full Text Available The competitive price game model is used to analyze the spectrum sharing problem in the cognitive radio networks, and the spectrum sharing problem with the constraints of available spectrum resource from primary users is further discussed in this paper. The Rockafeller multiplier method is applied to deal with the constraints of available licensed spectrum resource, and the improved profits function is achieved, which can be used to measure the impact of shared spectrum price strategies on the system profit. However, in the competitive spectrum sharing problem of practical cognitive radio network, primary users have to determine price of the shared spectrum without the acknowledgement of the other primary user’s price strategies. Thus a fast gradient iterative calculation method of equilibrium price is proposed, only with acknowledgement of the price strategies of shared spectrum during last cycle. Through the adaptive iteration at the direction with largest gradient of improved profit function, the equilibrium price strategies can be achieved rapidly. It can also avoid the predefinition of adjustment factor according to the parameters of communication system in conventional linear iteration method. Simulation results show that the proposed competitive price spectrum sharing model can be applied in the cognitive radio networks with constraints of available licensed spectrum, and it has better convergence performance.

Full color camouflage in a printable photonic blue-colored polymer

NARCIS (Netherlands)

Moirangthem, M.; Schenning, A.P.H.J.

2018-01-01

A blue reflective photonic polymer coating which can be patterned in full color, from blue to red, by printing with an aqueous calcium nitrate solution has been fabricated. Color change in the cholesteric liquid-crystalline polymer network over the entire visible spectrum is obtained by the use of

Notes on spectrum and exponential decay in nonautonomous evolutionary equations

Directory of Open Access Journals (Sweden)

Christian Pötzsche

2016-08-01

Full Text Available We first determine the dichotomy (Sacker-Sell spectrum for certain nonautonomous linear evolutionary equations induced by a class of parabolic PDE systems. Having this information at hand, we underline the applicability of our second result: If the widths of the gaps in the dichotomy spectrum are bounded away from $0$, then one can rule out the existence of super-exponentially decaying (i.e. slow solutions of semi-linear evolutionary equations.

Measurements of radio frequent cavity volt ages by X-ray spectrum measurements

Directory of Open Access Journals (Sweden)

Toprek Dragan

2005-01-01

Full Text Available This paper deals with X-ray spectrum measurement as a method for the measurement of radio frequent cavity voltage and the theory of X-ray spectrum calculation. Experimental results at 72 MHz for three different values of the radio frequent power of ACCEL K250 super conducting cyclotron are being presented.

CISAPS: Complex Informational Spectrum for the Analysis of Protein Sequences

Directory of Open Access Journals (Sweden)

Charalambos Chrysostomou

2015-01-01

Full Text Available Complex informational spectrum analysis for protein sequences (CISAPS and its web-based server are developed and presented. As recent studies show, only the use of the absolute spectrum in the analysis of protein sequences using the informational spectrum analysis is proven to be insufficient. Therefore, CISAPS is developed to consider and provide results in three forms including absolute, real, and imaginary spectrum. Biologically related features to the analysis of influenza A subtypes as presented as a case study in this study can also appear individually either in the real or imaginary spectrum. As the results presented, protein classes can present similarities or differences according to the features extracted from CISAPS web server. These associations are probable to be related with the protein feature that the specific amino acid index represents. In addition, various technical issues such as zero-padding and windowing that may affect the analysis are also addressed. CISAPS uses an expanded list of 611 unique amino acid indices where each one represents a different property to perform the analysis. This web-based server enables researchers with little knowledge of signal processing methods to apply and include complex informational spectrum analysis to their work.

Spectrum Sensing Experimentation for LTE and WiFi Unlicensed Band Operation

Directory of Open Access Journals (Sweden)

N. Milošević

2016-11-01

Full Text Available If several different systems operate in the same frequency band, a coordination between them is needed for effective use of the available spectrum. The coordination is especially important if the systems are not designed to operate in such an environment. The very important initial phase of the coordination process is acquiring of the spectrum usage map or spectrum sensing. The paper describes the spectrum sensing experimentation in the unlicensed 5 GHz band during the WiFi or LTE transmission. It describes the experiment workflow and depicts the obtained results. The experiments were performed at NITOS testbed at the University of Thessaly, Greece, and show that it is possible to determine whether WiFi or LTE transmission is sensed. Therefore, based on spectrum sensing it will be possible to coordinate a shared access of WiFi and LTE users in the unlicensed 5 GHz band.

A Review on Spectrum Sensing for Cognitive Radio: Challenges and Solutions

Directory of Open Access Journals (Sweden)

Yonghong Zeng

2010-01-01

Full Text Available Cognitive radio is widely expected to be the next Big Bang in wireless communications. Spectrum sensing, that is, detecting the presence of the primary users in a licensed spectrum, is a fundamental problem for cognitive radio. As a result, spectrum sensing has reborn as a very active research area in recent years despite its long history. In this paper, spectrum sensing techniques from the optimal likelihood ratio test to energy detection, matched filtering detection, cyclostationary detection, eigenvalue-based sensing, joint space-time sensing, and robust sensing methods are reviewed. Cooperative spectrum sensing with multiple receivers is also discussed. Special attention is paid to sensing methods that need little prior information on the source signal and the propagation channel. Practical challenges such as noise power uncertainty are discussed and possible solutions are provided. Theoretical analysis on the test statistic distribution and threshold setting is also investigated.

A Linear Mixed-Effects Model of Wireless Spectrum Occupancy

Directory of Open Access Journals (Sweden)

Pagadarai Srikanth

2010-01-01

Full Text Available We provide regression analysis-based statistical models to explain the usage of wireless spectrum across four mid-size US cities in four frequency bands. Specifically, the variations in spectrum occupancy across space, time, and frequency are investigated and compared between different sites within the city as well as with other cities. By applying the mixed-effects models, several conclusions are drawn that give the occupancy percentage and the ON time duration of the licensed signal transmission as a function of several predictor variables.

Spectrum Recombination.

Science.gov (United States)

Greenslade, Thomas B., Jr.

1984-01-01

Describes several methods of executing lecture demonstrations involving the recombination of the spectrum. Groups the techniques into two general classes: bringing selected portions of the spectrum together using lenses or mirrors and blurring the colors by rapid movement or foreshortening. (JM)

Hyponormal differential operators with discrete spectrum

Directory of Open Access Journals (Sweden)

Zameddin I. Ismailov

2010-01-01

Full Text Available In this work, we first describe all the maximal hyponormal extensions of a minimal operator generated by a linear differential-operator expression of the first-order in the Hilbert space of vector-functions in a finite interval. Next, we investigate the discreteness of the spectrum and the asymptotical behavior of the modules of the eigenvalues for these maximal hyponormal extensions.

TESTBED IMPLEMENTATION OF MULTI DIMENSIONAL SPECTRUM SENSING SCHEMES FOR COGNITIVE RADIO

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Deepa N Reddy

2016-06-01

Full Text Available Cognitive Radio (CR is a promising technology to exploit the underutilized spectrum. Spectrum sensing is one of the most important components for the establishment of cognitive radio system. Spectrum sensing allows the secondary users (SUs to detect the presence of the primary users (PUs. The aim of this work is to create a CR environment to study the spectrum sensing methods using Universal software radio Peripheral (USRP boards. In this paper a novel method of estimation of spectrum opportunities in multiple dimensions especially the space and the angle dimensions are carried out on USRP boards. This paper typically provides the experimental results carried out in an indoor wireless environment. To enhance the sensing performance the space dimension is firstly studied using spatial diversity of the cooperative SUs. Secondly the receiver diversity is analyzed using multiple antennas to enhance the error performance of the wireless system. The spectrum usage is also determined in the angle dimension by investigating the direction of the dominant signals using MUSIC algorithm.

Hγ Line Spectrum of Intermediate Polars

Directory of Open Access Journals (Sweden)

Yonggi Kim

1998-06-01

Full Text Available Kim & Beuermann (1995, 1996 have developed a model for the propagation of X-rays from the accreting white dwarf through the infalling material and the re-emission of the energy deposited by photo-absorption in the optical (and UV spectral range. By using this model, we calculate the profiles of the Hγ emission-line spectrum of intermediate polars. Photoabsorption of X-rays by the infalling material is the dominant process in forming the observed energy-dependent rotational modulation of the X-ray flux. X-ray and optical modulations are sensitive to model parameters in different ways. In principle, these dependencies allow us to obtain improved insight into the accretion geometry of the intermediate polars. We present results of our calculations and compare them with the Hβ line spectrum (Kim & Beuermann 1996.

Comparison of U and Np uptake on biogenic and abiotic ferrihydrite by XAFS

International Nuclear Information System (INIS)

Krawczyk-Baersch, Evelyn; Schmeide, Katja; Kvashnina, Kristina O.; Rossberg, Andre; Scheinost, Andreas C.

2017-01-01

XAS spectra of U and Np sorption biogenic ferrihydrite samples were compared to abiotic samples. The k 3 -weighted χ-spectrum and its Fourier-transform of the studied biogenic ferrihydrite sample bears close resemblance to the bidentate edge-sharing innersphere sorption 1 E complex, which is the main sorption species on abiotic ferrihydrite. Based on the shell fit analysis, the distances of the coordination shells U-O eq , U-O ax , and U-Fe are similar to those determined for abiotic ferrihydrite samples.

Spectrum Sensing and Primary User Localization in Cognitive Radio Networks via Sparsity

Directory of Open Access Journals (Sweden)

Lanchao Liu

2016-01-01

Full Text Available The theory of compressive sensing (CS has been employed to detect available spectrum resource in cognitive radio (CR networks recently. Capitalizing on the spectrum resource underutilization and spatial sparsity of primary user (PU locations, CS enables the identification of the unused spectrum bands and PU locations at a low sampling rate. Although CS has been studied in the cooperative spectrum sensing mechanism in which CR nodes work collaboratively to accomplish the spectrum sensing and PU localization task, many important issues remain unsettled. Does the designed compressive spectrum sensing mechanism satisfy the Restricted Isometry Property, which guarantees a successful recovery of the original sparse signal? Can the spectrum sensing results help the localization of PUs? What are the characteristics of localization errors? To answer those questions, we try to justify the applicability of the CS theory to the compressive spectrum sensing framework in this paper, and propose a design of PU localization utilizing the spectrum usage information. The localization error is analyzed by the Cramér-Rao lower bound, which can be exploited to improve the localization performance. Detail analysis and simulations are presented to support the claims and demonstrate the efficacy and efficiency of the proposed mechanism.

Oscillations in the spectrum of nonlinear Thomson-backscattered radiation

Directory of Open Access Journals (Sweden)

C. A. Brau

2004-02-01

Full Text Available When an electron beam collides with a high-intensity laser beam, the spectrum of the nonlinear Thomson scattering in the backward direction shows strong oscillations like those in the spectrum of an optical klystron. Laser gain on the backward Thomson scattering is estimated using the Madey theorem, and the results suggest that Thomson-backscatter free-electron lasers are possible at wavelengths extending to the far uv using a terawatt laser beam from a chirped-pulse amplifier and a high-brightness electron beam from a needle cathode.

Spectrum regulation for future internet networks in developing economies

CSIR Research Space (South Africa)

Somdyala, B

2017-05-01

Full Text Available to flourish and provide the necessary socio-economic benefit. This paper presents research to support formulation of the dynamic spectrum regulatory framework including co-existence techniques, interference avoidance and network device technology aspects...

Comparison of U and Np uptake on biogenic and abiotic ferrihydrite by XAFS

Energy Technology Data Exchange (ETDEWEB)

Krawczyk-Baersch, Evelyn [Helmholtz-Zentrum Dresden-Rossendorf e.V., Dresden (Germany). Biogeochemistry; Schmeide, Katja [Helmholtz-Zentrum Dresden-Rossendorf e.V., Dresden (Germany). Surface Processes; Kvashnina, Kristina O.; Rossberg, Andre; Scheinost, Andreas C. [Helmholtz-Zentrum Dresden-Rossendorf e.V., Dresden (Germany). Molecular Structures

2017-06-01

XAS spectra of U and Np sorption biogenic ferrihydrite samples were compared to abiotic samples. The k{sup 3}-weighted χ-spectrum and its Fourier-transform of the studied biogenic ferrihydrite sample bears close resemblance to the bidentate edge-sharing innersphere sorption {sup 1}E complex, which is the main sorption species on abiotic ferrihydrite. Based on the shell fit analysis, the distances of the coordination shells U-O{sub eq}, U-O{sub ax}, and U-Fe are similar to those determined for abiotic ferrihydrite samples.

Lifetime Autism Spectrum Features in a Patient with a Psychotic Mixed Episode Who Attempted Suicide

Directory of Open Access Journals (Sweden)

Marly Simoncini

2014-01-01

Full Text Available We present a case report of a young man who attempted suicide during a mixed episode with psychotic symptoms. The patient’s history revealed the lifetime presence of signs and features belonging to the autism spectrum realm that had been completely overlooked. We believe that this case is representative of an important and barely researched topic: what happens to children with nondiagnosed and nontreated subthreshold forms of autism when they grow old. The issue of early recognition of autism spectrum signs and symptoms is discussed, raising questions on the diagnostic boundaries between autism and childhood onset psychotic spectrums among patients who subsequently develop a full-blown psychotic disorder.

Full Spectrum Crashworthiness Criteria for Rotorcraft

Science.gov (United States)

2011-12-01

up) can be out of reach. With these aircraft configurations it is extremely valuable to have exits in the aircraft’s ceiling and/or floor when...entrapped air, brittle materials such as composites and glass , and even some metals. Experimentation to determine rate effects is difficult and time...82] Lebanon Sand [85] Bonnie Silt [86] Nevada Sand 40% [86] Nevada Sand 60% [86] Cuddleback Soil A [87] Cuddleback Soil B [87] Carson Sink Wet

Full Optical Spectrum Hyperspectral Scene Simulation

National Research Council Canada - National Science Library

Sandberg, Robert L; Richtsmeier, Steven; Haren, Raymond

2005-01-01

... with material-dependent bidirectional reflectance distribution functions (BRDFs), multiple scattering events, surface adjacency effects, and scattering, emission and shading by clouds, for arbitrary solar illumination and sensor viewing geometries...

Utility of an abbreviated version of the stanford-binet intelligence scales (5th ed.) in estimating 'full scale' IQ for young children with autism spectrum disorder.

Science.gov (United States)

Twomey, Conal; O'Connell, Helen; Lillis, Mary; Tarpey, Sarah Louise; O'Reilly, Gary

2018-03-01

The fifth edition of the Stanford-Binet Intelligence scales allows 'full scale' IQ (FSIQ) to be estimated using an abridged version of the test-the abbreviated battery IQ (ABIQ). Set within a public early intervention team service, the current cross-sectional study investigated the utility of the ABIQ in estimating FSIQ for 40 children with autism spectrum disorder (ASD) aged 3-5 years. A strong ABIQ-FSIQ association was yielded (r = 0.89; r 2  = 0.808) and the ABIQ did not over-estimate mean FSIQ above a clinically-relevant threshold; however, clinically significant over-estimation occurred in 17.5% of individual cases. While the findings provide support for the utility of the ABIQ in estimating FSIQ for young children with ASD, caution relating to the over-estimation of FSIQ is warranted. Careful clinical judgment-ideally based on examination of previous cognitive assessment results (if available), thorough interactional observations, and close multi-disciplinary consultation-is necessary to determine the applicability of the ABIQ to individual cases. Autism Res 2018, 11: 503-508. © 2017 International Society for Autism Research, Wiley Periodicals, Inc. We investigated the utility of a shortened version of the Stanford-Binet Intelligence Scales in estimating IQ for 40 young children with autism spectrum disorder (ASD). The findings provide qualified support for the instrument: acceptably accurate IQ estimation was achieved for most cases; but not so for a sizeable minority (17.5%). Careful clinical judgment is necessary to determine the applicability of the ABIQ to individual cases. © 2017 International Society for Autism Research, Wiley Periodicals, Inc.

Bottomonia: open bottom strong decays and spectrum

Directory of Open Access Journals (Sweden)

Santopinto E.

2014-05-01

Full Text Available We present our results for the bottomonium spectrum with self energy corrections. The bare masses used in the calculation are computed within Godfrey and Isgur’s relativized quark model. We also discuss our results for the open bottom strong decay widths of higher bottomonia in the 3P0 pair-creation model.

Optimal Pricing of Spectrum Resources in Wireless Opportunistic Access

Directory of Open Access Journals (Sweden)

Hanna Bogucka

2012-01-01

Full Text Available We consider opportunistic access to spectrum resources in cognitive wireless networks. The users equipment, or the network nodes in general are able to sense the spectrum and adopt a subset of available resources (the spectrum and the power individually and independently in a distributed manner, that is, based on their local channel quality information and not knowing the Channel State Information (CSI of the other nodes' links in the considered network area. In such a network scenery, the competition of nodes for available resources is observed, which can be modeled as a game. To obtain spectrally efficient and fair spectrum allocation in this competitive environment with the nodes having no information on the other players, taxation of resources is applied to coerce desired behavior of the competitors. In the paper, we present mathematical formulation of the problem of finding the optimal taxation rate (common for all nodes and propose a reduced-complexity algorithm for this optimization. Simulation results for these derived optimal values in various scenarios are also provided.

Seasonal changes in Fe species and soluble Fe concentration in the atmosphere in the Northwest Pacific region based on the analysis of aerosols collected in Tsukuba, Japan

Directory of Open Access Journals (Sweden)

Y. Takahashi

2013-08-01

Full Text Available Atmospheric iron (Fe can be a significant source of nutrition for phytoplankton inhabiting remote oceans, which in turn has a large influence on the Earth's climate. The bioavailability of Fe in aerosols depends mainly on the fraction of soluble Fe (= [FeSol]/[FeTotal], where [FeSol] and [FeTotal] are the atmospheric concentrations of soluble and total Fe, respectively. However, the numerous factors affecting the soluble Fe fraction have not been fully understood. In this study, the Fe species, chemical composition, and soluble Fe concentrations in aerosols collected in Tsukuba, Japan were investigated over a year (nine samples from December 2002 to October 2003 to identify the factors affecting the amount of soluble Fe supplied into the ocean. The soluble Fe concentration in aerosols is correlated with those of sulfate and oxalate originated from anthropogenic sources, suggesting that soluble Fe is mainly derived from anthropogenic sources. Moreover, the soluble Fe concentration is also correlated with the enrichment factors of vanadium and nickel emitted by fossil fuel combustion. These results suggest that the degree of Fe dissolution is influenced by the magnitude of anthropogenic activity, such as fossil fuel combustion. X-ray absorption fine structure (XAFS spectroscopy was performed in order to identify the Fe species in aerosols. Fitting of XAFS spectra coupled with micro X-ray fluorescence analysis (μ-XRF showed the main Fe species in aerosols in Tsukuba to be illite, ferrihydrite, hornblende, and Fe(III sulfate. Moreover, the soluble Fe fraction in each sample measured by leaching experiments is closely correlated with the Fe(III sulfate fraction determined by the XAFS spectrum fitting, suggesting that Fe(III sulfate is the main soluble Fe in the ocean. Another possible factor that can control the amount of soluble Fe supplied into the ocean is the total Fe(III concentration in the atmosphere, which was high in spring due to the high

A CR Spectrum Allocation Algorithm in Smart Grid Wireless Sensor Network

Directory of Open Access Journals (Sweden)

Wei He

2014-10-01

Full Text Available Cognitive radio (CR method was introduced in smart grid communication systems to resolve potential maladies such as the coexistence of heterogeneous networks, overloaded data flow, diversity in data structures, and unstable quality of service (QOS. In this paper, a cognitive spectrum allocation algorithm based on non-cooperative game theory is proposed. The CR spectrum allocation model was developed by modifying the traditional game model via the insertion of a time variable and a critical function. The computing simulation result shows that the improved spectrum allocation algorithm can achieve stable spectrum allocation strategies and avoid the appearance of multi-Nash equilibrium at the expense of certain sacrifices in the system utility. It is suitable for application in distributed cognitive networks in power grids, thus contributing to the improvement of the isomerism and data capacity of power communication systems.

A full-sunlight-driven photocatalyst with super long-persistent energy storage ability.

Science.gov (United States)

Li, Jie; Liu, Yuan; Zhu, Zhijian; Zhang, Guozhu; Zou, Tao; Zou, Zhijun; Zhang, Shunping; Zeng, Dawen; Xie, Changsheng

2013-01-01

A major drawback of traditional photocatalysts like TiO2 is that they can only work under illumination, and the light has to be UV. As a solution for this limitation, visible-light-driven energy storage photocatalysts have been developed in recent years. However, energy storage photocatalysts that are full-sunlight-driven (UV-visible-NIR) and possess long-lasting energy storage ability are lacking. Here we report, a Pt-loaded and hydrogen-treated WO3 that exhibits a strong absorption at full-sunlight spectrum (300-1,000 nm), and with a super-long energy storage time of more than 300 h to have formaldehyde degraded in dark. In this new material system, the hydrogen treated WO3 functions as the light harvesting material and energy storage material simultaneously, while Pt mainly acts as the cocatalyst to have the energy storage effect displayed. The extraordinary full-spectrum absorption effect and long persistent energy storage ability make the material a potential solar-energy storage and an effective photocatalyst in practice.

Crystal and electronic structure study of Mn doped wurtzite ZnO nanoparticles

Directory of Open Access Journals (Sweden)

O.M. Ozkendir

2016-08-01

Full Text Available The change in the crystal and electronic structure properties of wurtzite ZnO nanoparticles was studied according to Mn doping in the powder samples. The investigations were conducted by X-ray Absorption Fine Structure Spectroscopy (XAFS technique for the samples prepared with different heating and doping processes. Electronic analysis was carried out by the collected data from the X-ray Absorption Near-Edge Structure Spectroscopy (XANES measurements. Additional crystal structure properties were studied by Extended-XAFS (EXAFS analysis. Longer heating periods for the undoped wurtzite ZnO samples were determined to own stable crystal geometries. However, for some doped samples, the distortions in the crystal were observed as a result of the low doping amounts of Mn which was treated as an impurity. Besides, the changes in oxygen locations were determined to create defects and distortions in the samples.

Amplified spontaneous emission spectrum and gain characteristic of a two-electrode semiconductor optical amplifier

International Nuclear Information System (INIS)

Wang Hanchao; Huang Lirong; Shi Zhongwei

2011-01-01

A two-electrode multi-quantum-well semiconductor optical amplifier is designed and fabricated. The amplified spontaneous emission (ASE) spectrum and gain were measured and analyzed. It is shown that the ASE spectrum and gain characteristic are greatly influencedby the distribution of the injection current density. By changing the injection current density of two electrodes, the full width at half maximum, peak wavelength, peak power of the ASE spectrum and the gain characteristic can be easily controlled. (semiconductor devices)

Theory of pump–probe ultrafast photoemission and X-ray absorption spectra

Energy Technology Data Exchange (ETDEWEB)

Fujikawa, Takashi, E-mail: tfujikawa@faculty.chiba-u.jp; Niki, Kaori

2016-01-15

Highlights: • Pump–probe ultrafast XAFS and XPS spectra are theoretically studied. • Keldysh Green's function theory is applied. • Important many-body effects are explicitly included. - Abstract: Keldysh Green's function approach is extensively used in order to derive practical formulas to analyze pump–probe ultrafast photoemission and X-ray absorption spectra. Here the pump pulse is strong enough whereas the probe X-ray pulse can be treated by use of a perturbation theory. We expand full Green's function in terms of renormalized Green's function without the interaction between electrons and probe pulse. The present theoretical formulas allow us to handle the intrinsic and extrinsic losses, and furthermore resonant effects in X-ray Absorption Fine Structures (XAFS). To understand the radiation field screening in XPS spectra, we have to use more sophisticated theoretical approach. In the ultrafast XPS and XAFS analyses the intrinsic and extrinsic loss effects can interfere as well. In the XAFS studies careful analyses are necessary to handle extrinsic losses in terms of damped photoelectron propagation. The nonequilibrium dynamics after the pump pulse irradiation is well described by use of the time-dependent Dyson orbitals. Well above the edge threshold, ultrafast photoelectron diffraction and extended X-ray absorption fine structure (EXAFS) provide us with transient structural change after the laser pump excitations. In addition to these slow processes, the rapid oscillation in time plays an important role related to pump electronic excitations. Near threshold detailed information could be obtained for the combined electronic and structural dynamics. In particular high-energy photoemission and EXAFS are not so influenced by the details of excited states by pump pulse. Random-Phase Approximation (RPA)-boson approach is introduced to derive some practical formulas for time-dependent intrinsic amplitudes.

The influence of affective empathy and autism spectrum traits on empathic accuracy.

Directory of Open Access Journals (Sweden)

Marije aan het Rot

Full Text Available Autism spectrum disorder is characterized by interpersonal deficits and has been associated with limited cognitive empathy, which includes perspective taking, theory of mind, and empathic accuracy (EA. The capacity for affective empathy may also be impaired. In the present study we aimed to determine if EA in normally developing individuals with varying levels of autism spectrum traits is moderated by trait affective empathy. Fifty male and fifty female participants ('perceivers' completed the Autism-Spectrum Quotient and the Balanced Emotional Empathy Scale to assess autism spectrum traits and trait affective empathy, respectively. EA was assessed using a Dutch-language version of a previously developed task and involved rating the feelings of others ('targets' verbally recounting autobiographical emotional events. Targets varied in trait emotional expressivity, assessed using the Berkeley Expressivity Questionnaire. Perceivers with more autism spectrum traits performed worse on the EA task, particularly when their trait affective empathy was relatively low. Interpersonal deficits in autism spectrum disorder may be partially explained by low cognitive empathy. Further, they might be aggravated by a limited capacity for affective empathy.

Studying The Effect of Window type On Power Spectrum Based On MATLAB

Directory of Open Access Journals (Sweden)

Soad T. Abed

2012-06-01

Full Text Available The representation that describes signal’s frequency behavior can be divided into two categories: linear representation such as the Fourier-transform and quadratic representation such as power spectrum. Power spectrum characterizes the signal’s energy distribution in the frequency domain, and can answer whether most of the power of the signal resides at low or high frequencies. By performing spectral analysis, some important features of signals can be discovered that are not obvious in the time waveform of the signal. One problem with spectrum analysis is that the duration of the signals is finite, although adjustable. Applying the FFT method to finite duration sequences can produce inadequate results because of “spectral leakage”, to reduce the spectral leakage FFT window function is applied. Power spectrum parameters are window size, window type, window over lap and number of FFT. The aim of this work is to demonstrate the effect of varying window type on the power spectrum using Mat Lab software. Five windows have been compared to study their effect on the spectrum of a typical data.

A comprehensive review of the 1H-MRS metabolite spectrum in autism spectrum disorder.

Directory of Open Access Journals (Sweden)

Talitha eFord

2016-03-01

Full Text Available Neuroimaging studies of neuropsychiatric behaviour biomarkers across spectrum disorders are typically based on diagnosis, thus failing to account for the heterogeneity of multi-dimensional spectrum disorders such as autism (ASD. Control group trait phenotypes are also seldom reported. Proton magnetic resonance spectroscopy (1H-MRS measures the abundance of neurochemicals such as neurotransmitters and metabolites and hence can probe disorder phenotypes at clinical and sub-clinical levels. This detailed review summarises and critiques the current 1H-MRS research in ASD. The literature reports reduced N-acetylaspartate (NAA, glutamate and glutamine (Glx, gamma-aminobutyric acid (GABA, creatine and choline, and increased glutamate for children with ASD. Adult studies are few and results are inconclusive. Overall, the literature has several limitations arising from differences in 1H-MRS methodology and sample demographics. We argue that more consistent methods and greater emphasis on phenotype studies will advance understanding of underlying cortical metabolite disturbance in ASD, and the detection, diagnosis and treatment of ASD and other multi-dimensional psychiatric disorders.

Uranium, radium and thorium in soils with high-resolution gamma spectroscopy, MCNP-generated efficiencies, and VRF non-linear full-spectrum nuclide shape fitting

Science.gov (United States)

Metzger, Robert; Riper, Kenneth Van; Lasche, George

2017-09-01

A new method for analysis of uranium and radium in soils by gamma spectroscopy has been developed using VRF ("Visual RobFit") which, unlike traditional peak-search techniques, fits full-spectrum nuclide shapes with non-linear least-squares minimization of the chi-squared statistic. Gamma efficiency curves were developed for a 500 mL Marinelli beaker geometry as a function of soil density using MCNP. Collected spectra were then analyzed using the MCNP-generated efficiency curves and VRF to deconvolute the 90 keV peak complex of uranium and obtain 238U and 235U activities. 226Ra activity was determined either from the radon daughters if the equilibrium status is known, or directly from the deconvoluted 186 keV line. 228Ra values were determined from the 228Ac daughter activity. The method was validated by analysis of radium, thorium and uranium soil standards and by inter-comparison with other methods for radium in soils. The method allows for a rapid determination of whether a sample has been impacted by a man-made activity by comparison of the uranium and radium concentrations to those that would be expected from a natural equilibrium state.

[Application of wavelet transform and neural network in the near-infrared spectrum analysis of oil shale].

Science.gov (United States)

Li, Su-Yi; Ji, Yan-Ju; Liu, Wei-Yu; Wang, Zhi-Hong

2013-04-01

In the present study, an innovative method is proposed, employing both wavelet transform and neural network, to analyze the near-infrared spectrum data in oil shale survey. The method entails using db8 wavelet at 3 levels decomposition to process raw data, using the transformed data as the input matrix, and creating the model through neural network. To verify the validity of the method, this study analyzes 30 synthesized oil shale samples, in which 20 samples are randomly selected for network training, the other 10 for model prediction, and uses the full spectrum and the wavelet transformed spectrum to carry out 10 network models, respectively. Results show that the mean speed of the full spectrum neural network modeling is 570.33 seconds, and the predicted residual sum of squares (PRESS) and correlation coefficient of prediction are 0.006 012 and 0.843 75, respectively. In contrast, the mean speed of the wavelet network modeling method is 3.15 seconds, and the mean PRESS and correlation coefficient of prediction are 0.002 048 and 0.953 19, respectively. These results demonstrate that the wavelet neural network modeling method is significantly superior to the full spectrum neural network modeling method. This study not only provides a new method for more efficient and accurate detection of the oil content of oil shale, but also indicates the potential for applying wavelet transform and neutral network in broad near-infrared spectrum analysis.

Efficient Wideband Spectrum Sensing with Maximal Spectral Efficiency for LEO Mobile Satellite Systems

Directory of Open Access Journals (Sweden)

Feilong Li

2017-01-01

Full Text Available The usable satellite spectrum is becoming scarce due to static spectrum allocation policies. Cognitive radio approaches have already demonstrated their potential towards spectral efficiency for providing more spectrum access opportunities to secondary user (SU with sufficient protection to licensed primary user (PU. Hence, recent scientific literature has been focused on the tradeoff between spectrum reuse and PU protection within narrowband spectrum sensing (SS in terrestrial wireless sensing networks. However, those narrowband SS techniques investigated in the context of terrestrial CR may not be applicable for detecting wideband satellite signals. In this paper, we mainly investigate the problem of joint designing sensing time and hard fusion scheme to maximize SU spectral efficiency in the scenario of low earth orbit (LEO mobile satellite services based on wideband spectrum sensing. Compressed detection model is established to prove that there indeed exists one optimal sensing time achieving maximal spectral efficiency. Moreover, we propose novel wideband cooperative spectrum sensing (CSS framework where each SU reporting duration can be utilized for its following SU sensing. The sensing performance benefits from the novel CSS framework because the equivalent sensing time is extended by making full use of reporting slot. Furthermore, in respect of time-varying channel, the spatiotemporal CSS (ST-CSS is presented to attain space and time diversity gain simultaneously under hard decision fusion rule. Computer simulations show that the optimal sensing settings algorithm of joint optimization of sensing time, hard fusion rule and scheduling strategy achieves significant improvement in spectral efficiency. Additionally, the novel ST-CSS scheme performs much higher spectral efficiency than that of general CSS framework.

Pulsar Emission Spectrum

OpenAIRE

Gruzinov, Andrei

2013-01-01

Emission spectrum is calculated for a weak axisymmetric pulsar. Also calculated are the observed spectrum, efficiency, and the observed efficiency. The underlying flow of electrons and positrons turns out to be curiously intricate.

Self-disorders in schizophrenia-spectrum disorders

DEFF Research Database (Denmark)

Nordgaard, Julie; Nilsson, Lars Siersbæk; Sæbye, Ditte

2017-01-01

Self-disorders have been hypothesized to be an underlying and trait-like core feature of schizophrenia-spectrum disorders and a certain degree of temporal stability of self-disorders would therefore be expected. The aim of the study was to examine the persistence of self-disorders measured...... by the Examination of Anomalous Self Experiences over a time span of 5 years. 48 patients with schizophrenia-spectrum disorders were thoroughly assessed for psychopathology at baseline and 5 years later. Self-disorders were assessed by the Examination of Anomalous Self Experiences. The level of self-disorders...... was same at the two occasions for the full Examination of Anomalous Self Disorders and for four out of the five domains. For one domain, the level of self-disorders increased slightly from baseline to follow-up. The correlations between baseline and follow-up were moderate. 9 out of the 13 most...

Dynamic spectrum auction in wireless communication

CERN Document Server

Chen, Yanjiao

2015-01-01

This brief explores current research on dynamic spectrum auctions, focusing on fundamental auction theory, characteristics of the spectrum market, spectrum auction architecture and possible auction mechanisms. The brief explains how dynamic spectrum auctions, which enable new users to gain spectrum access and existing spectrum owners to obtain financial benefits, can greatly improve spectrum efficiency by resolving the artificial spectrum shortage. It examines why operators and users face significant challenges due to specialty of the spectrum market and the related requirements imposed on the auction mechanism design. Concise and up-to-date, Dynamic Spectrum Auction in Wireless Communication is designed for researchers and professionals in computer science or electrical engineering. Students studying networking will also find this brief a valuable resource.

Intermediate neutron spectrum problems and the intermediate neutron spectrum experiment

International Nuclear Information System (INIS)

Jaegers, P.J.; Sanchez, R.G.

1996-01-01

Criticality benchmark data for intermediate energy spectrum systems does not exist. These systems are dominated by scattering and fission events induced by neutrons with energies between 1 eV and 1 MeV. Nuclear data uncertainties have been reported for such systems which can not be resolved without benchmark critical experiments. Intermediate energy spectrum systems have been proposed for the geological disposition of surplus fissile materials. Without the proper benchmarking of the nuclear data in the intermediate energy spectrum, adequate criticality safety margins can not be guaranteed. The Zeus critical experiment now under construction will provide this necessary benchmark data

Autism Spectrum Disorder

Science.gov (United States)

... Caregiver Education » Fact Sheets Autism Spectrum Disorder Fact Sheet What is autism spectrum disorder? What are some ... of mutations in individual genes but rather spontaneous coding mutations across many genes. De novo mutations may ...

A neutron spectrum unfolding code based on iterative procedures

International Nuclear Information System (INIS)

Ortiz R, J. M.; Vega C, H. R.

2012-10-01

In this work, the version 3.0 of the neutron spectrum unfolding code called Neutron Spectrometry and Dosimetry from Universidad Autonoma de Zacatecas (NSDUAZ), is presented. This code was designed in a graphical interface under the LabVIEW programming environment and it is based on the iterative SPUNIT iterative algorithm, using as entrance data, only the rate counts obtained with 7 Bonner spheres based on a 6 Lil(Eu) neutron detector. The main features of the code are: it is intuitive and friendly to the user; it has a programming routine which automatically selects the initial guess spectrum by using a set of neutron spectra compiled by the International Atomic Energy Agency. Besides the neutron spectrum, this code calculates the total flux, the mean energy, H(10), h(10), 15 dosimetric quantities for radiation protection porpoises and 7 survey meter responses, in four energy grids, based on the International Atomic Energy Agency compilation. This code generates a full report in html format with all relevant information. In this work, the neutron spectrum of a 241 AmBe neutron source on air, located at 150 cm from detector, is unfolded. (Author)

Towards Harmonious Coexistence in the Unlicensed Spectrum: Rational Cooperation of Operators

Directory of Open Access Journals (Sweden)

Sunghwan Bae

2017-10-01

Full Text Available 5G New Radio (NR operating in the unlicensed spectrum is accelerating the Fourth Industrial Revolution by supporting Internet of Things (IoT networks or Industrial IoT deployments. Specifically, LTE-Advanced (LTE-A is looking to achieve spectrum integration through coexistence with multi-radio access technology (RAT systems in the same unlicensed bands with both licensed-assisted and stand-alone access. The listen-before-talk (LBT mechanism is mainly considered to enable an LTE operator to protect other incumbent unlicensed systems. In this article, we investigate the behaviors of multiple LTE operators along with the deployment of WiFi networks in the unlicensed spectrum from both short- and long-term points of view. In countries without mandatory LBT requirements, we show that an LTE operator is susceptible to collusion with another LTE operator, thus exploiting scarce spectrum resources by deceiving other wireless networks into thinking that channels are always busy; hence, mandatory usage of LTE with LBT is highly recommended at national level to achieve harmonious coexistence in the unlicensed spectrum. We discuss several possible coexistence scenarios to resolve the operator’s dilemmaas well as to improve unlicensed spectrum efficiency among multi-RAT systems, which is viable in the near future.

Understanding the Spectrum Environment: Data and Monitoring to Improve Spectrum Utilization

Data.gov (United States)

Networking and Information Technology Research and Development, Executive Office of the President — The Wireless Spectrum Research and Development Senior Steering Group (WSRD SSG) Workshop V titled: Understanding the Spectrum Environment: Data and Monitoring to...

Proof-of-Concept System for Opportunistic Spectrum Access in Multi-user Decentralized Networks

Directory of Open Access Journals (Sweden)

Sumit J. Darak

2016-09-01

Full Text Available Poor utilization of an electromagnetic spectrum and ever increasing demand for spectrum have led to surge of interests in opportunistic spectrum access (OSA based paradigms like cognitive radio and unlicensed LTE. In OSA for decentralized networks, frequency band selection from wideband spectrum is a challenging task since secondary users (SUs do not share any information with each other. In this paper, a new decision making policy (DMP has been proposed for OSA in the multi-user decentralized networks. First contribution is an accurate characterization of frequency bands using Bayes-UCB algorithm. Then, a novel SU orthogonization scheme using Bayes-UCB algorithm is proposed replacing randomization based scheme. At the end, USRP testbed has been developed for analyzing the performance of DMPs using real radio signals. Experimental results show that the proposed DMP offers significant improvement in spectrum utilization, fewer subband switching and collisions compared to other DMPs.

Joint switched multi-spectrum and transmit antenna diversity for spectrum sharing systems

KAUST Repository

Sayed, Mostafa M.

2013-10-01

In spectrum sharing systems, a secondary user (SU) is allowed to share the spectrum with a primary (licensed) network under the condition that the interference observed at the receivers of the primary users (PU-Rxs) is below a predetermined level. In this paper, we consider a secondary network comprised of a secondary transmitter (SU-Tx) equipped with multiple antennas and a single-antenna secondary receiver (SU-Rx) sharing the same spectrum with multiple primary users (PUs), each with a distinct spectrum. We develop transmit antenna diversity schemes at the SU-Tx that exploit the multi-spectrum diversity provided by the existence of multiple PUs so as to optimize the signal-to-noise ratio (SNR) at the SU-Rx. In particular, assuming bounded transmit power at the SU-Tx, we develop switched selection schemes that select the primary spectrum and the SU-Tx transmit antenna that maintain the SNR at the SU-Rx above a specific threshold. Assuming Rayleigh fading channels and binary phase-shift keying (BPSK) transmission, we derive the average bit-error-rate (BER) and average feedback load expressions for the proposed schemes. For the sake of comparison, we also derive a BER expression for the optimal selection scheme that selects the best antenna/spectrum pair that maximizes the SNR at the SU-Rx, in exchange of high feedback load and switching complexity. Finally, we show that our analytical results are in perfect agreement with the simulation results. © 2013 IEEE.

X-ray and Γ-ray spectroscopy of solids under pressure. Technical progress report, November 1996 - December 1998

International Nuclear Information System (INIS)

Ingalls, R.L.

1998-12-01

This report describes the recent synchrotron x-ray absorption fine structure (XAFS) measurements on a number of systems that undergo pressure induced changes in local structure at high pressure. The reader should also refer to the accompanying renewal proposal for a more in-depth discussion of the general scope of this program, and its relevance to condensed matter science. The author merely states that the methods here are aimed at using XAFS to probe the various phenomena that are caused by high pressure, especially including various structural, and/or electronic, changes or transitions. The general technique is based upon a pressure cell which utilizes sintered boron carbide anvils, since diamond anvils generally produce Bragg glitches which spoil the high quality XAFS necessary for precision structural measurements. Sample pressure is determined at the beam-line by measuring and analyzing, via XAFS, the compression of some cubic material contained within the sample chamber. Recently, the author has extended this work to 77 K using helium gas for the applied force, rather than hydraulic oil

Anharmonic correlated Debye model high-order expanded interatomic effective potential and Debye-Waller factors of bcc crystals

Energy Technology Data Exchange (ETDEWEB)

Van Hung, Nguyen, E-mail: hungnv@vnu.edu.vn [Department of Physics, Hanoi University of Science, 334 Nguyen Trai, Thanh Xuan, Hanoi (Viet Nam); Hue, Trinh Thi [Department of Physics, Hanoi University of Science, 334 Nguyen Trai, Thanh Xuan, Hanoi (Viet Nam); Khoa, Ha Dang [School of Engineering Physics, Hanoi University of Science and Technology, 1 Dai Co Viet, Hanoi (Viet Nam); Vuong, Dinh Quoc [Quang Ninh Education & Training Department, Nguyen Van Cu, Ha Long, Quang Ninh (Viet Nam)

2016-12-15

High-order expanded interatomic effective potential and Debye-Waller factors (DWFs) for local vibrational amplitudes in X-ray absorption fine structure (XAFS) of bcc crystals have been studied based on the anharmonic correlated Debye model. DWFs are presented in terms of cumulant expansion up to the fourth order and the many-body effects are taken into account in the present one-dimensional model based on the first shell near neighbor contribution approach used in the derivations of the anharmonic effective potential and XAFS cumulants where Morse potential is assumed to describe the single-pair atomic interaction. Analytical expressions for the dispersion relation, correlated Debye frequency and temperature and four first temperature-dependent XAFS cumulants have been derived based on the many-body perturbation approach. Thermodynamic properties and anharmonic effects in XAFS of bcc crystals described by the obtained cumulants have been in detail discussed. The advantage and efficiency of the present theory are illustrated by good agreement of the numerical results for Mo, Fe and W with experiment.

Light hadron spectrum from quenched lattice QCD. Results from the CP-PACS

International Nuclear Information System (INIS)

Yoshie, Tomoteru

2001-01-01

Deriving the light hadron spectrum from first principles of QCD has been a fundamental issue in elementary particle physics since the mid-1970s, when QCD was established. With this goal in mind, we have carried out large-scale simulations of lattice QCD on the CP-PACS computer. In this article, we present results for the light hadron spectrum derived in the quenched approximation to lattice QCD. We find that although the global structure of the observed spectrum is reproduced, the quenched spectrum systematically deviates from experiment when examined with an accuracy at better than a 10% level. Results for light quark masses are also reported. Another simulation of full QCD done recently (also on the CP-PACS computer) shows indications that the discrepancy observed in quenched QCD is significantly reduced by the introduction of two flavors of light dynamical quarks. (author)

Joint opportunistic beam and spectrum selection schemes for spectrum sharing systems with limited feedback

KAUST Repository

Sayed, Mostafa M.; Abdallah, Mohamed M.; Qaraqe, Khalid A.; Tourki, Kamel; Alouini, Mohamed-Slim

2014-01-01

Spectrum sharing systems have been introduced to alleviate the problem of spectrum scarcity by allowing an unlicensed secondary user (SU) to share the spectrum with a licensed primary user (PU) under acceptable interference levels to the primary

Cross-Layer Design in Dynamic Spectrum Sharing Systems

Directory of Open Access Journals (Sweden)

Shadmand A

2010-01-01

Full Text Available We consider a dynamic spectrum sharing system consisting of a primary user, whose licensed spectrum is allowed to be accessed by a secondary user as long as it does not violate the prescribed interference limit inflicted on the primary user. Assuming the Nakagami- block-fading environment, we aim at maximizing the performance of secondary user's link in terms of average spectral efficiency (ASE and error performance under the specified packet error rate (PER and average interference limit constraints. To this end, we employ a cross-layer design policy which combines adaptive power and coded discrete M-QAM modulation scheme at the physical layer with a truncated automatic repeat request (ARQ protocol at the data link layer, and simultaneously satisfies the aforementioned constraints. Numerical results affirm that the secondary link of spectrum sharing system combining ARQ with adaptive modulation and coding (AMC achieves significant gain in ASE depending on the maximum number of retransmissions initiated by the ARQ protocol. The results further indicate that the ARQ protocol essentially improves the packet loss rate performance of the secondary link.

Full L-S Band Telemetry System

National Research Council Canada - National Science Library

Jensen, Michael

2001-01-01

Recent changes in spectrum availability as well as higher demands for spectrum have motivated the development of telemetry transmit systems capable of fully operating over both L and S telemetry bands...

Full L-S Band Telemetry System

National Research Council Canada - National Science Library

Jensen, Michael

2003-01-01

Recent changes in spectrum availability as well as higher demands for spectrum have motivated the development of telemetry transmit systems capable of fully operating over both L and S telemetry bands...

Full L-S Band Telemetry System

National Research Council Canada - National Science Library

Jensen, Michael

2002-01-01

Recent changes in spectrum availability as well as higher demands for spectrum have motivated the development of telemetry transmit systems capable of fully operating over both L and S telemetry bands...

A Novel Spectrum Scheduling Scheme with Ant Colony Optimization Algorithm

Directory of Open Access Journals (Sweden)

Liping Liu

2018-01-01

Full Text Available Cognitive radio is a promising technology for improving spectrum utilization, which allows cognitive users access to the licensed spectrum while primary users are absent. In this paper, we design a resource allocation framework based on graph theory for spectrum assignment in cognitive radio networks. The framework takes into account the constraints that interference for primary users and possible collision among cognitive users. Based on the proposed model, we formulate a system utility function to maximize the system benefit. Based on the proposed model and objective problem, we design an improved ant colony optimization algorithm (IACO from two aspects: first, we introduce differential evolution (DE process to accelerate convergence speed by monitoring mechanism; then we design a variable neighborhood search (VNS process to avoid the algorithm falling into the local optimal. Simulation results demonstrate that the improved algorithm achieves better performance.

Fast Spectrum Reactors

CERN Document Server

Todd, Donald; Tsvetkov, Pavel

2012-01-01

Fast Spectrum Reactors presents a detailed overview of world-wide technology contributing to the development of fast spectrum reactors. With a unique focus on the capabilities of fast spectrum reactors to address nuclear waste transmutation issues, in addition to the well-known capabilities of breeding new fuel, this volume describes how fast spectrum reactors contribute to the wide application of nuclear power systems to serve the global nuclear renaissance while minimizing nuclear proliferation concerns. Readers will find an introduction to the sustainable development of nuclear energy and the role of fast reactors, in addition to an economic analysis of nuclear reactors. A section devoted to neutronics offers the current trends in nuclear design, such as performance parameters and the optimization of advanced power systems. The latest findings on fuel management, partitioning and transmutation include the physics, efficiency and strategies of transmutation, homogeneous and heterogeneous recycling, in addit...

Transcendental meditation for autism spectrum disorders? A perspective

Directory of Open Access Journals (Sweden)

David O. Black

2015-12-01

Full Text Available Anecdotal reports suggest that Transcendental Meditation (TM may be helpful for some children and young adults with autism spectrum disorders (ASDs. In this perspective piece, we present six carefully evaluated individuals with diagnosed ASDs, who appear to have benefitted from TM, and offer some thoughts as to how this technique might help such individuals.

Current Noise Spectrum of a Quantum Shuttle

DEFF Research Database (Denmark)

Flindt, Christian; Novotny, T.; Jauho, Antti-Pekka

2005-01-01

We present a method for calculating the full current noise spectrum S(omega) for the class of nano-electromechanical systems (NEMS) that can be described by a Markovian generalized master equation. As a specific example we apply the method to a quantum shuttle. The noise spectrum of the shuttle has...... peaks at integer multiples of the mechanical frequency, which is slightly renormalized. The renormalization explains a previously observed small deviation of the shuttle Current compared to the expected value given by the product of the natural mechanical frequency and the electron charge. For a certain...... parameter range the quantum shuttle exhibits a coexistence regime, where the charges are transported by two different mechanisms: Shuttling and sequential tunneling. In our previous studies we showed that characteristic features in the zero-frequency noise could be quantitatively understood as a slow...

Full dimensional (15-dimensional) quantum-dynamical simulation of the protonated water-dimer III: Mixed Jacobi-valence parametrization and benchmark results for the zero point energy, vibrationally excited states, and infrared spectrum.

Science.gov (United States)

Vendrell, Oriol; Brill, Michael; Gatti, Fabien; Lauvergnat, David; Meyer, Hans-Dieter

2009-06-21

Quantum dynamical calculations are reported for the zero point energy, several low-lying vibrational states, and the infrared spectrum of the H(5)O(2)(+) cation. The calculations are performed by the multiconfiguration time-dependent Hartree (MCTDH) method. A new vector parametrization based on a mixed Jacobi-valence description of the system is presented. With this parametrization the potential energy surface coupling is reduced with respect to a full Jacobi description, providing a better convergence of the n-mode representation of the potential. However, new coupling terms appear in the kinetic energy operator. These terms are derived and discussed. A mode-combination scheme based on six combined coordinates is used, and the representation of the 15-dimensional potential in terms of a six-combined mode cluster expansion including up to some 7-dimensional grids is discussed. A statistical analysis of the accuracy of the n-mode representation of the potential at all orders is performed. Benchmark, fully converged results are reported for the zero point energy, which lie within the statistical uncertainty of the reference diffusion Monte Carlo result for this system. Some low-lying vibrationally excited eigenstates are computed by block improved relaxation, illustrating the applicability of the approach to large systems. Benchmark calculations of the linear infrared spectrum are provided, and convergence with increasing size of the time-dependent basis and as a function of the order of the n-mode representation is studied. The calculations presented here make use of recent developments in the parallel version of the MCTDH code, which are briefly discussed. We also show that the infrared spectrum can be computed, to a very good approximation, within D(2d) symmetry, instead of the G(16) symmetry used before, in which the complete rotation of one water molecule with respect to the other is allowed, thus simplifying the dynamical problem.

Ultrahigh-energy cosmic-ray spectrum

International Nuclear Information System (INIS)

Hill, C.T.; Schramm, D.N.

1985-01-01

We analyze the evolution of the ultrahigh-energy cosmic-ray spectrum upon traversing the 2.7 0 K microwave background with respect to pion photoproduction, pair-production reactions, and cosmological effects. Our approach employs exact transport equations which manifestly conserve nucleon number and embody the laboratory details of these reactions. A spectrum enhancement appears around 6 x 10 19 eV due to the ''pile-up'' of energy-degraded nucleons, and a ''dip'' occurs around 10 19 eV due to combined effects. Both of these features appear in the observational spectrum. We analyze the resulting neutrino spectrum and the effects of cosmological source distributions. We present a complete model of the ultrahigh-energy spectrum and anisotropy in reasonable agreement with observation and which predicts an observable electron-neutrino spectrum

Unfolding measurement of the atmospheric muon neutrino spectrum using IceCube

Energy Technology Data Exchange (ETDEWEB)

Boerner, Mathis; Ruhe, Tim; Meier, Maximilian; Schlunder, Philipp; Menne, Thorben; Fuchs, Tomasz [Dept. of Physics, Technical University of Dortmund, 44227 Dortmund (Germany); Collaboration: IceCube-Collaboration

2016-07-01

IceCube is a cubic kilometer neutrino observatory located at the geographic South Pole. With its huge volume, the detector is well suited for measurements of the atmospheric muon neutrino energy spectrum. Over the last years, several unfolding analyses for single years were able to provide model independent measurements for the northern hemisphere in an energy region between 200 GeV and 3.2 PeV. In this talk, the extension of the analyses to four additional years of data is presented. With this significant enlargement of the data basis, it is possible to reanalyze the full northern hemisphere with smaller statistical errors. Moreover, the spectrum can be unfolded in several small zenith bands. Measurements of the energy spectrum for different zenith regions provide further information on the composition and the shape of the flux.

Two-zone model for the broadband Crab nebula spectrum: microscopic interpretation

Directory of Open Access Journals (Sweden)

Fraschetti F.

2017-01-01

Full Text Available We develop a simple two-zone interpretation of the broadband baseline Crab nebula spectrum between 10−5 eV and ~ 100 TeV by using two distinct log-parabola energetic electrons distributions. We determine analytically the very-high energy photon spectrum as originated by inverse-Compton scattering of the far-infrared soft ambient photons within the nebula off a first population of electrons energized at the nebula termination shock. The broad and flat 200 GeV peak jointly observed by Fermi/LAT and MAGIC is naturally reproduced. The synchrotron radiation from a second energetic electron population explains the spectrum from the radio range up to ~ 10 keV. We infer from observations the energy dependence of the microscopic probability of remaining in proximity of the shock of the accelerating electrons.

Spectrum Band Selection in Delay-QoS Constrained Cognitive Radio Networks

KAUST Repository

Yang, Yuli; Aï ssa, Sonia; Salama, Khaled N.

2014-01-01

links are investigated for both criteria under two spectrum-sharing constraints. To begin by presenting full benefits in these criteria, the constraint imposed on the secondary transmitter (ST) is the average interference limitation to PUs only

The GEANT4 simulation study of the characteristic γ-ray spectrum of TNT under soil induced by DT neutron

International Nuclear Information System (INIS)

Qin Xue; Han Jifeng; Yang Chaowen

2014-01-01

The characteristic γ-ray spectrum of TNT under soil induced by DT neutron is measured based on the PFTNA demining system. GEANT4 Monte Carlo simulation toolkit is used to simulate the whole experimental procedure. The simulative spectrum is compared with the experimental spectrum. The result shows that they are mainly consistent. It is for the first time to analyze the spectrum by Monte Carlo simulation, the share of the background sources such as neutron, gamma are obtained, the contribution that the experimental apparatus such as shielding, detector sleeve, moderator make to the background is analysed. The study found that the effective gamma signal (from soil and TNT) is only 29% of the full-spectrum signal, and the background signal is more than 68% of the full-spectrum signal, which is mainly produced in the shielding and the detector sleeve. The simulation result shows that by gradually improving the shielding and the cadmium of the detector sleeve, the share of the effective gamma signal can increase to 36% and the background signal can fell 7% eventually. (authors)

Spectrum Handoffs Based on Preemptive Repeat Priority Queue in Cognitive Radio Networks

Directory of Open Access Journals (Sweden)

Xiaolong Yang

2016-07-01

Full Text Available Cognitive radio can significantly improve the spectrum efficiency, and spectrum handoff is considered as an important functionality to guarantee the quality of service (QoS of primary users (PUs and the continuity of data transmission of secondary users (SUs. In this paper, we propose an analytical framework based on a preemptive repeat identical (PRI M/G/1 queuing network model to characterize spectrum handoff behaviors with general service time distribution of both primary and secondary connections, multiple interruptions and transmission delay resulting from the appearance of primary connections. Then, we derive the close-expression of the extended data delivery and the system sojourn time in both staying and changing scenarios. In addition, based on analysis of spectrum handoff behaviors resulting from multiple interruptions caused by the appearance of the primary connections, we investigate the traffic-adaptive policy, by which the considered SU will optimally adjust its handoff spectrum policy. Moreover, we investigate the admissible region and provide the reference for designing the admission control rule for the arriving secondary connection requests. Finally, simulation results verify that our proposed analytical framework is reasonable and can provide the reference for executing the optimal spectrum handoff strategy and designing the admission control rule for the SU in cognitive radio networks.

Electronic structure study of Co doped CeO2 nanoparticles using X-ray absorption fine structure spectroscopy

International Nuclear Information System (INIS)

Kumar, Shalendra; Gautam, Sanjeev; Song, T.K.; Chae, Keun Hwa; Jang, K.W.; Kim, S.S.

2014-01-01

Highlights: • The electronic structural of Co–CeO 2 nanoparticles is investigated using XAFS. • Ce M 5,4 , Ce L 3 and O K edge NEXAFS reveal that the Ce-ions are in +4 valence state. • The NEXAFS spectrum performed at Co L3,2-edge confirms Co-ion in 2+ state. • The EXAFS analysis also show that Co ions are occupying Ce position in doped CeO 2 . • The distances between Ce–O and Ce–Ce/Co in all shells decreases with Co doping. - Abstract: We investigated the electronic structure of well characterized Co doped CeO 2 nanoparticles using X-ray absorption fine structure (XAFS) spectroscopy. Near edge X-ray absorption fine structure (NEXAFS) spectra at Ce M 5,4 , Ce L 3 and O K-edge conclude that the Ce-ions are in +4 valence state in pure as well as in Co doped CeO 2 nanoparticles. The local structure around Ce-atom in Co doped CeO 2 nanoparticles was also determined using extended X-ray absorption fine structure (EXAFS) spectroscopy at Ce L 3 edge. The EXAFS analysis suggest that the inter-atomic distance of Ce–O, Ce–Ce/Co decreases with Co doping, which indicate a contraction of the lattice. The decease in Ce–O distance also reflect that there is a formation of oxygen vacancies in CeO 2 matrix. The Debye–Waller factor also shows the consistent behaviour for all the coordination shells. The atomic multiplet calculations for Co L 3,2 -edge was performed to determine the valence state, symmetry and field splitting, which reflect that Co-ions are in 2+ state and substituted at Ce-site with crystal field splitting of 10Dq=-0.57eV. The XAFS measurements reveal that the Co-ions occupy the Ce position in the CeO 2 host matrix and create a oxygen vacancy

Lattice distortions in TlInSe{sub 2} thermoelectric material studied by X-ray absorption fine structure

Energy Technology Data Exchange (ETDEWEB)

Hosokawa, Shinya; Stellhorn, Jens Ruediger [Department of Physics, Kumamoto University, Kumamoto (Japan); Ikemoto, Hiroyuki [Department of Physics, University of Toyama, Toyama (Japan); Mimura, Kojiro [Department of Mathematical Sciences, Graduate School of Engineering, Osaka Prefecture University, Sakai (Japan); Wakita, Kazuki [Faculty of Engineering, Chiba Institute of Technology, Narashino (Japan); Mamedov, Nazim [Institute of Physics, Azerbaijan National Academy of Sciences, Baku (Azerbaijan)

2018-01-15

Tl L{sub II} and In K X-ray absorption fine structure (XAFS) measurements were performed on a TlInSe{sub 2} thermoelectric material in the temperature range of 25-300 K including the incommensurate-commensurate phase transition temperature of about 135 K. Most of the bond lengths obtained from the present XAFS measurements are in good agreement with existing X-ray diffraction data at room temperature, while only the Tl-Tl correlation shows inconsistent values indicating the commensurate properties of the Tl chains expected from the thermodynamic properties. The present XAFS data clearly support positional fluctuations of the Tl atoms found in three-dimensional atomic images reconstructed from X-ray fluorescence holography. (copyright 2017 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

Ambiguities in the deduction of rest frame fluctuation spectrums from spectrums computed in moving frames

International Nuclear Information System (INIS)

Fredericks, R.W.; Coroniti, F.V.

1976-01-01

The problem of interpretation of power spectrums computed by Fourier analysis of data time series taken in frames moving with respect to the medium containing the fluctuations is examined. It is found that no unique connection exists between the rest frame power spectrum as a function of scale length and the derived power spectrum as a function 'frequency' computed from the time series data taken in the moving frame. This caused by a complex Doppler-shifting phenomenon that leads to a basically aliased frequency spectrum in the moving frame. Examples of nonuniqueness are given for various types of rest frame density or wave turbulence that lead to the same frequency dependence of the power spectrum computed in the moving frame. This has implications for the past interpretations of power spectrums of density or magnetic field fluctuations from satellites or interplanetary probes

Quasi-Compact Perturbations of the Weyl Essential Spectrum and Application to Singular Transport Operators

Directory of Open Access Journals (Sweden)

Leila Mebarki

2015-11-01

Full Text Available This paper is devoted to the investigation of the stability of the Weyl essential spectrum of closed densely dened linear operator A subjected to additive perturbation K such that (lambda-A-K^{-1}K or K(lambda-A-K^{-1} is a quasi-compact operator. The obtained results are used to describe the Weyl essential spectrum of singular neutron transport operator.

An approach to electromagnetic spectrum evaluation and control for situational awareness

CSIR Research Space (South Africa)

Olivier, K

2012-10-01

Full Text Available In this presentation the author provides insight on the role of modern electronic warfare technology for the purposes of electromagnetic spectrum evaluation and control, which plays a crucial role in situational awareness required for peacekeeping...

Sexuality and gender role in autism spectrum disorder: a case control study.

Directory of Open Access Journals (Sweden)

Susanne Bejerot

Full Text Available The 'extreme male brain theory of autism' describes an extreme male pattern of cognitive traits defined as strong systemising abilities paired with empathising weaknesses in autism spectrum disorder. However, beyond these cognitive traits, clinical observations have suggested an ambiguous gender-typed pattern regarding several sexually dimorphic traits. The aim of the present study was to investigate if patterns of non-cognitive sexually dimorphic traits differed between the autism spectrum disorder and control groups. Fifty adults with autism spectrum disorder and intelligence within the normal range, and 53 neurotypical controls responded to questions on gender role, self-perceived gender typicality and gender identity, as well as sexuality. Measures used were a Swedish modification of the Bem Sex Role Inventory and questions on sexuality and gender designed for the purpose of this study. Our results showed that one common gender role emerged in the autism spectrum disorder group. Masculinity (e.g. assertiveness, leadership and competitiveness was weaker in the autism spectrum disorder group than in the controls, across men and women. Self-perceived gender typicality did not differ between the groups but tomboyism and bisexuality were overrepresented amongst women with autism spectrum disorder. Lower libido was reported amongst both male and female participants with autism spectrum disorder compared with controls. We conclude that the extreme male patterns of cognitive functions in the autistic brain do not seem to extend to gender role and sexuality. A gender-atypical pattern for these types of characteristics is suggested in autism spectrum disorder.

A Spectrum Allocation Mechanism Based on HJ-DQPSO for Cognitive Radio Networks

Directory of Open Access Journals (Sweden)

Zhu Jiang

2015-11-01

Full Text Available In cognitive radio network model consisting of secondary users and primary users, in order to solve the difficult multi-objective spectrum allocation issue about maximizing network efficiency and users’ fairness to access network, this paper proposes a new discrete multi-objective combinatorial optimization mechanism—HJ-DQPSO based on Hooke Jeeves (HJ and Quantum Particle Swarm Optimization (QPSO algorithm. The mechanism adopts HJ algorithm to local search to prevent falling into the local optimum, and proposes a discrete QPSO algorithm to match the discrete spectrum assignment model. The mechanism has the advantages of approximating optimal solution, rapid convergence, less parameters, avoiding falling into local optimum. Compared with existing spectrum assignment algorithms, the simulation results show that according to different optimization objectives, the HJ-DQPSO optimization mechanism for multi-objective optimization can better approximate optimal solution and　converge fast. We can obtain a reasonable spectrum allocation scheme in the case of satisfying multiple optimization objectives.

Model independent foreground power spectrum estimation using WMAP 5-year data

International Nuclear Information System (INIS)

Ghosh, Tuhin; Souradeep, Tarun; Saha, Rajib; Jain, Pankaj

2009-01-01

In this paper, we propose and implement on WMAP 5 yr data a model independent approach of foreground power spectrum estimation for multifrequency observations of the CMB experiments. Recently, a model independent approach of CMB power spectrum estimation was proposed by Saha et al. 2006. This methodology demonstrates that the CMB power spectrum can be reliably estimated solely from WMAP data without assuming any template models for the foreground components. In the current paper, we extend this work to estimate the galactic foreground power spectrum using the WMAP 5 yr maps following a self-contained analysis. We apply the model independent method in harmonic basis to estimate the foreground power spectrum and frequency dependence of combined foregrounds. We also study the behavior of synchrotron spectral index variation over different regions of the sky. We use the full sky Haslam map as an external template to increase the degrees of freedom, while computing the synchrotron spectral index over the frequency range from 408 MHz to 94 GHz. We compare our results with those obtained from maximum entropy method foreground maps, which are formed in pixel space. We find that relative to our model independent estimates maximum entropy method maps overestimate the foreground power close to galactic plane and underestimates it at high latitudes.

Joint switched multi-spectrum and transmit antenna diversity for spectrum sharing systems

KAUST Repository

Sayed, Mostafa M.; Abdallah, Mohamed M.; Qaraqe, Khalid A.; Alouini, Mohamed-Slim

2013-01-01

. In this paper, we consider a secondary network comprised of a secondary transmitter (SU-Tx) equipped with multiple antennas and a single-antenna secondary receiver (SU-Rx) sharing the same spectrum with multiple primary users (PUs), each with a distinct spectrum

Modeling the bacterial photosynthetic reaction center. VII. Full simulation of the intervalence hole-transfer absorption spectrum of the special-pair radical cation

International Nuclear Information System (INIS)

Reimers, Jeffrey R.; Hush, Noel S.

2003-01-01

ENDOR data suggests that the special-pair radical cation P + from Rhodobacter sphaeroides is 68% localized on P L while simple interpretations of FTIR difference spectra based primarily on intensity information, but to some extent also bandwidths, suggest near-complete charge localization. We provide a complete a priori spectral simulation of the spectrum of P + in the range 0-5000 cm-1, including explicit treatment of the high-resolution vibrational transitions, the low-resolution hole-transfer absorption centered at 2700 cm-1, and the resonance with the SHOMO to HOMO transition at 2200 cm-1 that resolve the issues concerning the nature of P + . The description of the vibrational aspects of the problem were taken from results of previous density-functional calculations, and a qualitatively realistic large number of vibrational modes (50 antisymmetric and 18-20 symmetric) were included. To facilitate the calculations, a new representation of the vibronic-coupling Hamiltonian for intervalence hole-transfer or electron-transfer problems is introduced, allowing the spectrum to be simulated efficiently using only up to 4x10 9 vibronic basis functions and leading also to new general analytical relationships. Observed spectra are fitted using seven adjustable chemical parameters describing the interactions between the four electronic states involved. The resulting fits provide unique descriptions of the parameters that are insensitive to the source of the observed spectrum or the nature of the symmetric modes used in the model, and all fitted parameters are found to be close in value to those from independent estimates. We determine the electronic coupling, antisymmetric-mode reorganization energy, and redox asymmetry to be J=0.126±0.002 eV, λ=0.139±0.003 eV, and E 0 =0.069±0.002 eV, respectively. Our description forms the basis of understanding for a wide range of other properties observed for Rhodobacter sphaeroides mutants, as well as the properties of the

Full cycle rapid scan EPR deconvolution algorithm.

Science.gov (United States)

Tseytlin, Mark

2017-08-01

Rapid scan electron paramagnetic resonance (RS EPR) is a continuous-wave (CW) method that combines narrowband excitation and broadband detection. Sinusoidal magnetic field scans that span the entire EPR spectrum cause electron spin excitations twice during the scan period. Periodic transient RS signals are digitized and time-averaged. Deconvolution of absorption spectrum from the measured full-cycle signal is an ill-posed problem that does not have a stable solution because the magnetic field passes the same EPR line twice per sinusoidal scan during up- and down-field passages. As a result, RS signals consist of two contributions that need to be separated and postprocessed individually. Deconvolution of either of the contributions is a well-posed problem that has a stable solution. The current version of the RS EPR algorithm solves the separation problem by cutting the full-scan signal into two half-period pieces. This imposes a constraint on the experiment; the EPR signal must completely decay by the end of each half-scan in order to not be truncated. The constraint limits the maximum scan frequency and, therefore, the RS signal-to-noise gain. Faster scans permit the use of higher excitation powers without saturating the spin system, translating into a higher EPR sensitivity. A stable, full-scan algorithm is described in this paper that does not require truncation of the periodic response. This algorithm utilizes the additive property of linear systems: the response to a sum of two inputs is equal the sum of responses to each of the inputs separately. Based on this property, the mathematical model for CW RS EPR can be replaced by that of a sum of two independent full-cycle pulsed field-modulated experiments. In each of these experiments, the excitation power equals to zero during either up- or down-field scan. The full-cycle algorithm permits approaching the upper theoretical scan frequency limit; the transient spin system response must decay within the scan

PROSPECTS OF DIAGNOSTICS OF AUTISM SPECTRUM DISORDERS IN CHILDREN

Directory of Open Access Journals (Sweden)

O. G. Novoselova

2014-01-01

Full Text Available The relevance of a problem of autism spectrum disorder in children and the modern view on etiology and pathogenesis of these states are revealed in the article. Autism classification according to the International classification of diseases of the 10th revision adopted in Russia and important changes of a new classifier of the American psychiatric association concerning autism spectrum disorders are considered. The difficulties connected with diagnostics of autism spectrum disorders in children, autism comorbidity and some other psychiatric nosologies and the necessity of detailed differential diagnostics for a circle of these diseases are mentioned. Autism spectrum disorders are presented from the point of view of clinical genetics, the necessity of medical genetic consultation in diagnosing is proved. Definition of complex and essential autism is given. A number of widespread genetic syndromes with the description of clinical characteristics and molecular genetic mechanisms underlying the pathogenesis is allocated in the group of complex autism. Difficulties of molecular genetic confirmation of the diagnosis are revealed, the algorithm of search of mutations and the short description of methods of diagnostics are given. The efficiency of standard procedure of molecular genetic diagnostics at each stage, according to literary data, is shown in the group of children with essential autism. The opportunities and advantages of a method of the chromosomal micromatrix analysis as one of available modern methods of molecular genetic diagnostics in the group of children with autism spectrum disorders are highlighted on the example of extended microdeletion and microduplicational syndromes.

Association of Broad- vs Narrow-Spectrum Antibiotics With Treatment Failure, Adverse Events, and Quality of Life in Children With Acute Respiratory Tract Infections.

Science.gov (United States)

Gerber, Jeffrey S; Ross, Rachael K; Bryan, Matthew; Localio, A Russell; Szymczak, Julia E; Wasserman, Richard; Barkman, Darlene; Odeniyi, Folasade; Conaboy, Kathryn; Bell, Louis; Zaoutis, Theoklis E; Fiks, Alexander G

2017-12-19

Acute respiratory tract infections account for the majority of antibiotic exposure in children, and broad-spectrum antibiotic prescribing for acute respiratory tract infections is increasing. It is not clear whether broad-spectrum treatment is associated with improved outcomes compared with narrow-spectrum treatment. To compare the effectiveness of broad-spectrum and narrow-spectrum antibiotic treatment for acute respiratory tract infections in children. A retrospective cohort study assessing clinical outcomes and a prospective cohort study assessing patient-centered outcomes of children between the ages of 6 months and 12 years diagnosed with an acute respiratory tract infection and prescribed an oral antibiotic between January 2015 and April 2016 in a network of 31 pediatric primary care practices in Pennsylvania and New Jersey. Stratified and propensity score-matched analyses to account for confounding by clinician and by patient-level characteristics, respectively, were implemented for both cohorts. Broad-spectrum antibiotics vs narrow-spectrum antibiotics. In the retrospective cohort, the primary outcomes were treatment failure and adverse events 14 days after diagnosis. In the prospective cohort, the primary outcomes were quality of life, other patient-centered outcomes, and patient-reported adverse events. Of 30 159 children in the retrospective cohort (19 179 with acute otitis media; 6746, group A streptococcal pharyngitis; and 4234, acute sinusitis), 4307 (14%) were prescribed broad-spectrum antibiotics including amoxicillin-clavulanate, cephalosporins, and macrolides. Broad-spectrum treatment was not associated with a lower rate of treatment failure (3.4% for broad-spectrum antibiotics vs 3.1% for narrow-spectrum antibiotics; risk difference for full matched analysis, 0.3% [95% CI, -0.4% to 0.9%]). Of 2472 children enrolled in the prospective cohort (1100 with acute otitis media; 705, group A streptococcal pharyngitis; and 667, acute sinusitis), 868

Photovoltaic yield: correction method for the mismatch between the solar spectrum and the reference ASTMG AM1.5G spectrum

Directory of Open Access Journals (Sweden)

Mambrini Thomas

2015-01-01

Full Text Available We propose a method for a spectral correction of the predicted PV yield and we show the importance of the spectral mismatch on the solar cell. Indeed, currently predicted PV yield are made considering solar irradiation, ambient temperature, incidence angle and partially (or not the solar spectrum. However, the solar spectrum is not always the same. It varies depending on the site location, atmospheric conditions, time of the day...This may impact the photovoltaic solar cells differently according to their technology (crystalline Silicon, thin film, multi-junctions... This paper presents a method for calculating the correction of the short-circuit current of a photovoltaic cell due to the mismatch of the solar spectrum with the reference ASTM AM1.5G spectrum, for a specific site, throughout the year, using monthly data of AERONET (AErosol RObotic NETwork established by NASA and CNRS and the model SMARTS (simple model for atmospheric transmission of sunshine developed by the NREL. We applied this correction method on the site of Palaiseau (France, 48.7°N, 2.2°E, 156 m, close to our laboratory, just for comparison and the example of Blida (Algeria, 36°N, 2°E, 230 m is given for one year. This example illustrates the importance of this spectral correction to better estimate the photovoltaic yield. To be more precise, instead of modeling the solar spectral distribution, one can measure it with a spectro-radiometer, and then, derive the spectral mismatch correction. Some of our typical measurements are presented in this paper.

Spectrum of human tails: A report of six cases

Directory of Open Access Journals (Sweden)

Biswanath Mukhopadhyay

2012-01-01

Full Text Available Human tail is a curiosity, a cosmetic stigma and presents as an appendage in the lumbosacral region. Six patients of tail in the lumbosacral region are presented here to discuss the spectrum of presentation of human tails. The embryology, pathology and treatment of this entity are discussed along with a brief review of the literature.

Investigation of influence of electronic irradiation on photoluminescence spectrum and ir-spectrum of porous silicon

International Nuclear Information System (INIS)

Daineko, E.A.; Dihanbayev, K.K.; Akhtar, P.; Hussain, A.

2007-01-01

In this article we study the influence of 2-Mev electron irradiation on porous silicon (PS). Photoluminescence (PL) spectrum and IR-spectrum have been done on both newly-prepared PS samples and samples prepared a year ago after the irradiation. We analyzed PL spectrum for both types of PS samples. The experimental results suggest that the peak position in PL spectrum decreases for newly-prepared PS samples. The size of the nanocrystals calculated by the method of singling out of spectrum components was equal to 3.0-3.2 nm. Porosity of the samples was 60-75%. From IR-spectrum of newly-prepared PS samples wide absorption band was observed at 1100 cm/sup -1/ (Si-O-Si bond). Another peak of Si-O-Si group was observed at 850 cm/sub -1/. Also hydrogen absorption bands were appearing from 2000 to 2200 cm/sup -1/, corresponding to vibration modes SiH, SiH/sub 2/, SiH/sub 3/. As a result of electron irradiation the PL intensity of newly-prepared PS samples decreases abruptly by a factor of 30 without peak shifting. As for the samples prepared a year ago we observed a decrease in the PL intensity by 25-30%. From IR-spectrum of PS samples prepared a year ago it was shown that the intensity of bridge bonds corresponding to absorption band 850 cm/sup -1/, decreases gradually. Our experimental data shows that PS samples stored for longer time have better radiation resistant properties than the newly-prepared PS samples due to the replacement of Si-H bonds with more resistant Si-O bonds. Porous silicon, electrochemical anodizing, photoluminescence spectrum, IR-spectrum, electronic irradiation. (author)

Spectrum Utilisation and Management in Cognitive Radio Networks

DEFF Research Database (Denmark)

Patil, Kishor P.

have confirmed this by showing that the considerable amount of radio spectrum is underutilized. Dynamic Spectrum Access (DSA) and the spectrum refarming are the two viable solutions for the problem of spectrum scarcity. In DSA, unlicensed user opportunistically uses the vacant licensed spectrum...... of licensed spectrum provides efficient use of spectrum. Spectrum refarming means the recovery of spectrum from its existing users for the purpose of re-assignment, either for new uses, or for the introduction of new spectrally efficient technologies. Spectrum refarming is a spectrum management tool that can......In recent years, the demand for radio spectrum for wireless communication is growing due to increase in number of users and popularity of data and multimedia services. This has been observed in the recent auctions completed word wide for the vestige of radio spectrum. The radio spectrum has been...

Structures in the primary spectrum

International Nuclear Information System (INIS)

Kempa, J.; Knurenko, S.P.; Malecki, R.

2009-01-01

Structures in the energy spectrum of primary cosmic rays at the 'knee' region and for energies higher than 1 EeV are obtained through studying extensive air showers (EAS). The main problem of the research is the fact that we work in the ranges of highly fluctuating parameters used to obtain the primary energy spectrum. In this paper the log-normal distribution for the error function has been used in convolution with the power spectrum to explain the Yakutsk experimental data. Similar results have been obtained for the gamma distribution as the error function. Using the power law primary spectrum in the energy region around 10 19 eV we will argue that the primary Yakutsk spectrum is overestimated. In the best case this overestimation is not less than 42%.

Building Cultural Capability for Full-Spectrum Operations

Science.gov (United States)

2008-01-01

Mol, Born, Willemsen, & Van der Molen , 2005; Caligiuri & Day, 2000). In addition to these broad traits, antecedents to cross-cultural competence...510-517. 18 Mol, S. T., Born, M. P., Willemsen, M. E., & Van Der Molen , H. T. (2005). Predicting expatriate job performance for selection purposes: A...et al., 2003). In addition, self-regulation has been shown to be critical for adjustment (Matsumoto et al., 2003; van Oudenhoven, Mol, & Van der Zee

Building Cultural Capability for Full-Spectrum Operations

National Research Council Canada - National Science Library

Abbe, Allison

2008-01-01

.... In particular, interpersonal skills, non-ethnocentric attitudes, and openness emerged from workshop discussions and the literature as some of the most consistent contributors to success in cross-cultural settings...

Enhanced proapoptotic gene expression of XAF1, CASP8 and TNFSF10 in the bovine endometrium during early pregnancy is not correlated with augmented apoptosis.

Science.gov (United States)

Groebner, A E; Schulke, K; Unterseer, S; Reichenbach, H D; Reichenbach, M; Büttner, M; Wolf, E; Meyer, H H D; Ulbrich, S E

2010-03-01

Bovine trophoblast cells release interferon-tau (IFNT), a type I IFN, as the pregnancy recognition signal. Since type I IFNs exert growth inhibitory and proapoptotic actions, the effect of the conceptus on components of the apoptosis pathways was determined in the bovine endometrium during the periimplantation period. Uteri of Simmental heifers were flushed post mortem at days 12, 15, and 18 of cycle or pregnancy for the recovery of conceptuses and the sampling of ipsilateral endometrial tissue at slaughter for quantitative RT-PCR, immunohistochemistry, caspase activity and TUNEL assays. Endometrium samples of pregnant animals revealed increased transcript levels for the proapoptotic genes XAF1 (day 15: 2.9-fold; day 18: 15.1-fold; p=0.005) and CASP8 (day 18: 2.4-fold; p=0.007). The mRNA expression increased significantly with the day of the cycle for the proapoptotic genes FASLG, TNFSF10, TNF and TNFSF1A (p=0.004, p=0.006, p=0.001 and p=0.007) and the antiapoptotic gene BIRC4 (p=0.03). We detected high amounts of FASLG transcripts in day 18 conceptuses (16-fold higher than day 18 endometria). This finding was validated at the protein level by immunohistochemistry. To further analyse the endometrial activation of the caspase cascade, the activities of initiator caspase 8 and effector caspases 3/7 were determined luminometrically. No difference between pregnant and cyclic animals was found for either caspase activity. Additionally, a TUNEL assay showed no increase of apoptotic cells in the pregnant endometrium. In conclusion, although the bovine conceptus induces the expression of proapoptotic genes, neither an activation of a caspase cascade nor an increase of apoptotic cells was noticed. These results suggest inhibitory mechanisms preventing endometrial cells from programmed cell death. Copyright 2009 Elsevier Ltd. All rights reserved.

In situ XAFS studies of the oxygen reduction reaction on carbon supported platinum and platinum nickel nano-scale alloys as cathode catalysts in fuel cells

Science.gov (United States)

Jia, Qingying

Platinum based bimetallic alloys have been investigated by conducting Pt L3 and Ni K edge in situ XAFS measurements on carbon supported Pt and PtNi(1:1) nanoscale catalysts under a wide range of operating potentials. We observed that (1) the Pt-Pt bond distance in PtNi alloys is shorter than that of Pt, and the bond distance between Pt and oxygen adsorbate is longer for PtNi. (2) Pt has a tendency to stay on the surface while Ni is mostly underneath the surface. (3) While a change in oxidation of pure Pt was clearly observed at different potentials, the Pt in the PtNi alloy remained nearly oxygen-free at all potentials, but an accompanying oxidation change of Ni was observed instead. (4) PtNi has higher open circuit voltage than Pt/C. These results indicate that the chemisorption energy between Pt and oxygen adsorbate is reduced in PtNi alloys, which prevents the poison of oxygen adsorbate and hence improves the reactivity. In addition, the strain and ligand effects in PtNi nanoparticle alloys were studied by FEW calculations using experimental data as a guide to understand the factors causing the reduction of chemisorptions energy of Pt. Our calculation indicates that Pt d-band is broader and lower in energy when the bond distance between Pt is shorter, resulting in weaker chemisorption energy between Pt and absorbed oxygen atom on top, and vice verse. Meanwhile, the investigation of ligand effect shows two trends in modifying Pt's properties within alloyed transition metals. The strain effect dominates in PtNi bimetallic system, corresponding to weaker chemisorptions energy and lower white intensity of Pt L3 edge, which is in consistent with our experimental results. The implications of these results afford a good guideline in understanding the reactivity enhancement mechanism and in the context of alloy catalysts design.

An Auction-Based Spectrum Leasing Mechanism for Mobile Macro-Femtocell Networks of IoT

Directory of Open Access Journals (Sweden)

Xin Chen

2017-02-01

Full Text Available The Internet of Things (IoT is a vision of the upcoming society. It can provide pervasive communication between two or more entities using 4G-LTE (Long Term Evolution communication technology. In 4G-LTE networks, there are two important problems: helping manage the spectrum demands of IoT devices and achieving much more revenue with the limited resource. This paper proposes a pricing framework to investigate the spectrum leasing in mobile heterogeneous networks with single macrocell and multiple femtocells. We modeled the leasing procedure between the macrocell service provider (MSP and femtocell holders (FHs as an auction to motivate the MSP to lease its spectrum resource. All FHs act as the bidders, and the monopolist MSP acts as the auctioneer. In the auction, FHs submit their bids to rent the spectrum resource so that they can make a profit by selling it to their subscribers. The MSP determines the spectrum leasing amount and chooses the winning FHs by solving the dynamic programming-based 0–1 knapsack problem. In our proposed framework, we focus on the spectrum pricing strategy and revenue maximization of the MSP. The simulation results show that the proposed scheme provides effective motivation for the MSP to lease the spectrum to FHs, and both the MSP and FHs can benefit from spectrum leasing.

Relationship between motor abilities and severity of autism spectrum disorder

Directory of Open Access Journals (Sweden)

Cvijetić Marija

2017-01-01

Full Text Available According to the findings in literature, motor skills of children with autism spectrum disorders generally differ from age expectations and are increasingly being associated with speech and language and social development, and adaptive behavior. The aim of the research was to determine the relationship between the development level of fine and gross motor skills and autism severity of children with autism spectrum disorder. The sample included 30 children with autism spectrum disorder and associated intellectual disability, seven to 19 years of age (M=11.97; SD=3.70. The assessment was conducted using the Peabody Motor Development Scale, the Vineland Adaptive Behavior Scale, and the criteria for describing the level of severity of autism spectrum disorder (APA, 2013. The results have shown that participants' motor skills significantly correlate with social communication (Peabody fine motor skills r=-0.452; p=0.012; Vineland fine motor skills r=-0.511; p=0.004; Vineland total r=-0.391; p=0.032 and restricted, repetitive behaviors (Peabody fine motor skills r=-0.383; p=0.037; Vineland fine motor skills r=-0.433; p=0.017; Vineland total r=-0.371; p=0.044. Lower level of autistic symptomatology is associated with higher motor achievements. It is necessary to pay more attention to the assessment and treatment of motor skills in children with autism spectrum disorder, given the established delay in the development of these skills, and bearing in mind their relationship with the severity of the symptoms of autism spectrum disorder. Timely identification of motor disorders would allow the use of early treatment and potentially lead to better results, compared to later inclusion in intervention programs.

Modal spectrum in spontaneous parametric down-conversion with noncollinear phase matching

CSIR Research Space (South Africa)

Zhang, Y

2014-06-01

Full Text Available We investigate the effect of the down-conversion angle between the signal and idler beams in spontaneous parametric down-conversion on the bandwidth of the modal spectrum (Schmidt number) of the down-converted quantum state. For this purpose, we...

Hybrid spread spectrum radio system

Science.gov (United States)

Smith, Stephen F [London, TN; Dress, William B [Camas, WA

2010-02-09

Systems and methods are described for hybrid spread spectrum radio systems. A method, includes receiving a hybrid spread spectrum signal including: fast frequency hopping demodulating and direct sequence demodulating a direct sequence spread spectrum signal, wherein multiple frequency hops occur within a single data-bit time and each bit is represented by chip transmissions at multiple frequencies.

Local structure of disordered Au-Cu and Au-Ag alloys

International Nuclear Information System (INIS)

Frenkel, A. I.; Machavariani, V. Sh.; Rubshtein, A.; Rosenberg, Yu.; Voronel, A.; Stern, E. A.

2000-01-01

X-ray-absorption fine structure (XAFS) and x-ray-diffraction (XRD) measurements of disordered alloys Au x Cu 1-x and Au 0.5 Ag 0.5 prepared by melt spinning were performed. In the Au 0.5 Ag 0.5 alloy, no significant local deviations of the atoms from the average fcc lattice were detected while in Au x Cu 1-x alloys, significant deviations of atoms from the average fcc lattice were found. Mean-square vibrations of the Cu-Cu distances revealed by the XAFS in Au x Cu 1-x alloys indicate the weakening of contact between Cu atoms in the dilute limit. Our computer simulation for Au x Cu 1-x clusters of 10 5 atoms reproduces the main features of both the XAFS and XRD data

Many channel spectrum unfolding

International Nuclear Information System (INIS)

Najzer, M.; Glumac, B.; Pauko, M.

1980-01-01

The principle of the ITER unfolding code as used for the many channel spectrum unfolding is described. Its unfolding ability is tested on seven typical neutron spectra. The effect of the initial spectrum approximation upon the solution is discussed

Target Channel Visiting Order Design Using Particle Swarm Optimization for Spectrum Handoff in Cognitive Radio Networks

Directory of Open Access Journals (Sweden)

Shilian Zheng

2014-08-01

Full Text Available In a dynamic spectrum access network, when a primary user (licensed user reappears on the current channel, cognitive radios (CRs need to vacate the channel and reestablish a communications link on some other channel to avoid interference to primary users, resulting in spectrum handoff. This paper studies the problem of designing target channel visiting order for spectrum handoff to minimize expected spectrum handoff delay. A particle swarm optimization (PSO based algorithm is proposed to solve the problem. Simulation results show that the proposed algorithm performs far better than random target channel visiting scheme. The solutions obtained by PSO are very close to the optimal solution which further validates the effectiveness of the proposed method.

Setting scene for TV white spaces and dynamic spectrum access in South Africa

CSIR Research Space (South Africa)

Masonta, MT

2012-05-01

Full Text Available -and-control static spectrum regulation regime. In order to keep up with a growing demand for wireless broadband access; new and dynamic spectrum regulation and management approaches are crucial. The ongoing global television (TV) broadcast digital switchover (DSO... ?white spaces? (TVWS). In the US, for example, TV DSO was completed in June 2009. However, this was not a smooth process. For instance, it was reported that digital TV viewers from many cities experienced several reception problems [2]. Due...

Autism Spectrum Disorder (ASD)

Science.gov (United States)

... Español (Spanish) Recommend on Facebook Tweet Share Compartir Autism spectrum disorder (ASD) is a developmental disability that can cause ... work. Autism: What's New MMWR article: Prevalence of Autism Spectrum Disorder Data Community Report Press release: Autism Prevalence Slightly ...

Exact spectrum of non-linear chirp scaling and its application in geosynchronous synthetic aperture radar imaging

Directory of Open Access Journals (Sweden)

Chen Qi

2013-07-01

Full Text Available Non-linear chirp scaling (NLCS is a feasible method to deal with time-variant frequency modulation (FM rate problem in synthetic aperture radar (SAR imaging. However, approximations in derivation of NLCS spectrum lead to performance decline in some cases. Presented is the exact spectrum of the NLCS function. Simulation with a geosynchronous synthetic aperture radar (GEO-SAR configuration is implemented. The results show that using the presented spectrum can significantly improve imaging performance, and the NLCS algorithm is suitable for GEO-SAR imaging after modification.

Measurement of 235U fission spectrum-averaged cross sections and neutron spectrum adjusted with the activation data

International Nuclear Information System (INIS)

Kobayashi, Katsuhei; Kobayashi, Tooru

1992-01-01

The 235 U fission spectrum-averaged cross sections for 13 threshold reactions were measured with the fission plate (27 cm in diameter and 1.1 cm thick) at the heavy water thermal neutron facility of the Kyoto University Reactor. The Monte Carlo code MCNP was applied to check the deviation from the 235 U fission neutron spectrum due to the room-scattered neutrons, and it was found that the resultant spectrum was close to that of 235 U fission neutrons. Supplementally, the relations to derive the absorbed dose rates with the fission plate were also given using the calculated neutron spectra and the neutron Kerma factors. Finally, the present values of the fission spectrum-averaged cross sections were employed to adjust the 235 U fission neutron spectrum with the NEUPAC code. The adjusted spectrum showed a good agreement with the Watt-type fission neutron spectrum. (author)

Robust Spectrum Sensing Demonstration Using a Low-Cost Front-End Receiver

Directory of Open Access Journals (Sweden)

Daniele Borio

2015-01-01

Full Text Available Spectrum Sensing (SS is an important function in Cognitive Radio (CR to detect primary users. The design of SS algorithms is one of the most challenging tasks in CR and requires innovative hardware and software solutions to enhance detection probability and minimize low false alarm probability. Although several SS algorithms have been developed in the specialized literature, limited work has been done to practically demonstrate the feasibility of this function on platforms with significant computational and hardware constraints. In this paper, SS is demonstrated using a low cost TV tuner as agile front-end for sensing a large portion of the Ultra-High Frequency (UHF spectrum. The problems encountered and the limitations imposed by the front-end are analysed along with the solutions adopted. Finally, the spectrum sensor developed is implemented on an Android device and SS implementation is demonstrated using a smartphone.

The marine diversity spectrum

DEFF Research Database (Denmark)

Reuman, Daniel C.; Gislason, Henrik; Barnes, Carolyn

2014-01-01

of taxonomy (all the species in a region regardless of clade) are much less studied but are equally important and will illuminate a different set of ecological and evolutionary processes. We develop and test a mechanistic model of how diversity varies with body mass in marine ecosystems. The model predicts...... the form of the diversity spectrum', which quantifies the distribution of species' asymptotic body masses, is a species analogue of the classic size spectrum of individuals, and which we have found to be a new and widely applicable description of diversity patterns. The marine diversity spectrum...... is predicted to be approximately linear across an asymptotic mass range spanning seven orders of magnitude. Slope -0 center dot 5 is predicted for the global marine diversity spectrum for all combined pelagic zones of continental shelf seas, and slopes for large regions are predicted to lie between -0 center...

Low-Altitude and Slow-Speed Small Target Detection Based on Spectrum Zoom Processing

Directory of Open Access Journals (Sweden)

Xuwang Zhang

2018-01-01

Full Text Available This paper proposes a spectrum zoom processing based target detection algorithm for detecting the weak echo of low-altitude and slow-speed small (LSS targets in heavy ground clutter environments, which can be used to retrofit the existing radar systems. With the existing range-Doppler frequency images, the proposed method firstly concatenates the data from the same Doppler frequency slot of different images and then applies the spectrum zoom processing. After performing the clutter suppression, the target detection can be finally implemented. Through the theoretical analysis and real data verification, it is shown that the proposed algorithm can obtain a preferable spectrum zoom result and improve the signal-to-clutter ratio (SCR with a very low computational load.

Performance Analysis of Ad Hoc Dispersed Spectrum Cognitive Radio Networks over Fading Channels

Directory of Open Access Journals (Sweden)

Mohammad Muneer

2011-01-01

Full Text Available Cognitive radio systems can utilize dispersed spectrum, and thus such approach is known as dispersed spectrum cognitive radio systems. In this paper, we first provide the performance analysis of such systems over fading channels. We derive the average symbol error probability of dispersed spectrum cognitive radio systems for two cases, where the channel for each frequency diversity band experiences independent and dependent Nakagami- fading. In addition, the derivation is extended to include the effects of modulation type and order by considering M-ary phase-shift keying ( -PSK and M-ary quadrature amplitude modulation -QAM schemes. We then consider the deployment of such cognitive radio systems in an ad hoc fashion. We consider an ad hoc dispersed spectrum cognitive radio network, where the nodes are assumed to be distributed in three dimension (3D. We derive the effective transport capacity considering a cubic grid distribution. Numerical results are presented to verify the theoretical analysis and show the performance of such networks.

Spectrum resolving power of hearing: measurements, baselines, and influence of maskers

Directory of Open Access Journals (Sweden)

Alexander Ya. Supin

2011-06-01

Full Text Available Contemporary methods of measurement of frequency tuning in the auditory system are reviewed. Most of them are based on the frequency-selective masking paradigm and require multi-point measurements (a number of masked thresholds should be measured to obtain a single frequency-tuning estimate. Therefore, they are rarely used for practical needs. As an alternative approach, frequency-selective properties of the auditory system may be investigated using probes with complex frequency spectrum patterns, in particular, rippled noise that is characterized by a spectrum with periodically alternating maxima and minima. The maximal ripple density discriminated by the auditory system is  a convenient measure of the spectrum resolving power (SRP. To find the highest resolvable ripple density, a phase-reversal test has been suggested. Using this technique, normal SRP, its dependence on probe center frequency, spectrum contrast, and probe level were measured. The results were not entirely predictable by frequency-tuning data obtained by masking methods. SRP is influenced by maskers, with on- and off-frequency maskers influencing SRP very differently. Dichotic separation of the probe and masker results in almost complete release of SRP from influence of maskers.

Dual-sensing porphyrin-containing copolymer nanosensor as full-spectrum colorimeter and ultra-sensitive thermometer.

Science.gov (United States)

Yan, Qiang; Yuan, Jinying; Kang, Yan; Cai, Zhinan; Zhou, Lilin; Yin, Yingwu

2010-04-28

A porphyrin-containing copolymer has dual-sensing in response to metal ions and temperature as a novel nanosensor. Triggered by ions, the sensor exhibits full-color tunable behavior as a cationic detector and colorimeter. Responding to temperature, the sensor displays an "isothermal" thermochromic point as an ultra-sensitive thermometer.

Least-squares adjustment of a 'known' neutron spectrum: The importance of the covariance matrix of the input spectrum

International Nuclear Information System (INIS)

Mannhart, W.

1986-01-01

Based on the responses of 25 different neutron activation detectors, the neutron spectrum of Cf-252 hs been adjusted with least-squares methods. For a fixed input neutron spectrum, the covariance matrix of this spectrum has been systematically varied to investigate the influence of this matrix on the final result. The investigation showed that the adjusted neutron spectrum is rather sensitive to the structure of the covariance matrix for the input spectrum. (author)

Intellectual Profiles in the Autism Spectrum and Other Neurodevelopmental Disorders

Science.gov (United States)

Mouga, Susana; Café, Cátia; Almeida, Joana; Marques, Carla; Duque, Frederico; Oliveira, Guiomar

2016-01-01

The influence of specific autism spectrum disorder (ASD) deficits in Intelligence Quotients (IQ), Indexes and subtests from the Wechsler Intelligence Scale for Children-III was investigated in 445 school-aged children: ASD (N = 224) and other neurodevelopmental disorders (N = 221), matched by Full-Scale IQ and chronological age. ASD have lower…

Regression in autistic spectrum disorders.

Science.gov (United States)

Stefanatos, Gerry A

2008-12-01

A significant proportion of children diagnosed with Autistic Spectrum Disorder experience a developmental regression characterized by a loss of previously-acquired skills. This may involve a loss of speech or social responsitivity, but often entails both. This paper critically reviews the phenomena of regression in autistic spectrum disorders, highlighting the characteristics of regression, age of onset, temporal course, and long-term outcome. Important considerations for diagnosis are discussed and multiple etiological factors currently hypothesized to underlie the phenomenon are reviewed. It is argued that regressive autistic spectrum disorders can be conceptualized on a spectrum with other regressive disorders that may share common pathophysiological features. The implications of this viewpoint are discussed.

Interference management with partial uplink/downlink spectrum overlap

KAUST Repository

Randrianantenaina, Itsikiantsoa

2016-07-26

Simultaneous reuse of spectral resources by uplink and downlink, denoted as in-band full duplex (FD) communication, is promoted to double the spectral efficiency when compared to its half-duplex (HD) counterpart. Interference management, however, remains challenging in FD cellular networks, especially when high disparity between uplink and downlink transmission powers exists. The uplink performance can be particularly deteriorated when operating on channels that are simultaneously occupied with downlink transmission. This paper considers a cellular wireless system with partial spectrum overlap between the downlink and uplink. The performance of the system becomes, therefore, a function of the overlap fraction, as well as the power levels of both the uplink and downlink transmissions. The paper considers the problem of maximizing an overall network utility to find the uplink/downlink transmission powers and the spectrum overlap fraction between the uplink and downlink spectrum in each cell, and proposes solving the problem using interior point method. Simulations results confirm the vulnerability of the uplink performance to the FD operation, and show the superiority of the proposed scheme over the FD and HD schemes. The results further show that explicit uplink and downlink performance should be considered for efficient design of cellular networks with overlapping uplink/downlink resources. © 2016 IEEE.

A correlation between RSSI and height in UHF band and comparison of geolocation spectrum database view of TVWS

CSIR Research Space (South Africa)

Maliwatu, R

2016-12-01

Full Text Available antenna. Thus, the power incident onto the antenna, Pinc, may be estimated via the power entering the spectrum analyser, Psa, as Pinc = Psa + Lc −GA = Psa − 1.1, (dB). (1) 3.1 First set of spectrum scan measurements The first round of measurements...

Market-driven spectrum sharing in cognitive radio

CERN Document Server

Yi, Changyan

2016-01-01

This brief focuses on the current research on mechanism design for dynamic spectrum sharing in cognitive radio (CR) networks. Along with a review of CR architectures and characteristics, this brief presents the motivations, significances and unique challenges of implementing algorithmic mechanism design for encouraging both primary spectrum owners and secondary spectrum users to participate in dynamic spectrum sharing. The brief then focuses on recent advances in mechanism design in CR networks. With an emphasis on dealing with the uncertain spectrum availabilities, mechanisms based on spectrum recall, two-stage spectrum sharing and online spectrum allocation are introduced with the support of theoretic analyses and numerical illustrations. The brief concludes with a discussion of potential research directions and interests, which will motivate further studies on mechanism design for wireless communications. This brief is concise and approachable for researchers, professionals and advanced-level students in w...

Opportunistic spectrum utilization in vehicular communication networks

CERN Document Server

Cheng, Nan

2016-01-01

This brief examines current research on improving Vehicular Networks (VANETs), examining spectrum scarcity due to the dramatic growth of mobile data traffic and the limited bandwidth of dedicated vehicular communication bands and the use of opportunistic spectrum bands to mitigate congestion. It reviews existing literature on the use of opportunistic spectrum bands for VANETs, including licensed and unlicensed spectrum bands and a variety of related technologies, such as cognitive radio, WiFi and device-to-device communications. Focused on analyzing spectrum characteristics, designing efficient spectrum exploitation schemes, and evaluating the date delivery performance when utilizing different opportunistic spectrum bands, the results presented in this brief provide valuable insights on improving the design and deployment of future VANETs.

Speech Enhancement by Multichannel Crosstalk Resistant ANC and Improved Spectrum Subtraction

Directory of Open Access Journals (Sweden)

Zeng Qingning

2006-01-01

Full Text Available A scheme combining multichannel crosstalk resistant adaptive noise cancellation (MCRANC algorithm and improved spectrum subtraction (ISS algorithm is presented to enhance noise carrying speech signals. The scheme would permit locating the microphones in close proximity by virtue of using MCRANC which has the capability of removing the crosstalk effect. MCRANC would also permit canceling out nonstationary noise and making the residual noise more stationary for further treatment by ISS algorithm. Experimental results have indicated that this scheme outperforms many commonly used techniques in the sense of SNR improvement and music effect reduction which is an inevitable byproduct of the spectrum subtraction algorithm.

Contribution of Strong Discontinuities to the Power Spectrum of the Solar Wind

International Nuclear Information System (INIS)

Borovsky, Joseph E.

2010-01-01

Eight and a half years of magnetic field measurements (2 22 samples) from the ACE spacecraft in the solar wind at 1 A.U. are analyzed. Strong (large-rotation-angle) discontinuities in the solar wind are collected and measured. An artificial time series is created that preserves the timing and amplitudes of the discontinuities. The power spectral density of the discontinuity series is calculated and compared with the power spectral density of the solar-wind magnetic field. The strong discontinuities produce a power-law spectrum in the ''inertial subrange'' with a spectral index near the Kolmogorov -5/3 index. The discontinuity spectrum contains about half of the power of the full solar-wind magnetic field over this ''inertial subrange.'' Warnings are issued about the significant contribution of discontinuities to the spectrum of the solar wind, complicating interpretation of spectral power and spectral indices.

Autism Spectrum Disorders (ASD) and Diet

Science.gov (United States)

... Conditions Autism Autism Spectrum Disorders (ASD) and Diet Autism Spectrum Disorders (ASD) and Diet By Karen Ansel, MS, RDN, CDN Published April 2, 2018 nambitomo/iStock/Thinkstock Autism Spectrum Disorder, or ASD, is a complex developmental and neurological ...

Stoppage in Autism Spectrum Disorders

DEFF Research Database (Denmark)

Grønborg, Therese Koops; Hansen, Stefan Nygaard; Nielsen, Svend V

2015-01-01

of bias in sibling recurrence risk estimation. This study investigated whether stoppage occurs in Danish families with a firstborn child diagnosed with autism spectrum disorders, and if stoppage was differential. We found that stoppage occurs moderately in Danish families affected by autism spectrum...... disorders, and that stoppage is differential. However, differential stoppage is a minor source of estimation bias in Danish sibling recurrence risk studies of autism spectrum disorders....

THE STUDY OF SPECTRUM RECONSTRUCTION BASED ON FUZZY SET FULL CONSTRAINT AND MULTIENDMEMBER DECOMPOSITION

Directory of Open Access Journals (Sweden)

Y. Sun

2017-09-01

Full Text Available Hyperspectral imaging system can obtain spectral and spatial information simultaneously with bandwidth to the level of 10 nm or even less. Therefore, hyperspectral remote sensing has the ability to detect some kinds of objects which can not be detected in wide-band remote sensing, making it becoming one of the hottest spots in remote sensing. In this study, under conditions with a fuzzy set of full constraints, Normalized Multi-Endmember Decomposition Method (NMEDM for vegetation, water, and soil was proposed to reconstruct hyperspectral data using a large number of high-quality multispectral data and auxiliary spectral library data. This study considered spatial and temporal variation and decreased the calculation time required to reconstruct the hyper-spectral data. The results of spectral reconstruction based on NMEDM showed that the reconstructed data has good qualities and certain applications, which makes it possible to carry out spectral features identification. This method also extends the application of depth and breadth of remote sensing data, helping to explore the law between multispectral and hyperspectral data.

Autism spectrum disorder - Asperger syndrome

Science.gov (United States)

... part of the larger developmental disorder category of autism spectrum disorder . ... American Psychiatric Association. Autism spectrum disorder. ... VA: American Psychiatric Publishing: 2013;50-59. Raviola GJ, ...

Spectrum Trading in India and 5G

DEFF Research Database (Denmark)

Tripathi, Purnendu; Prasad, Ramjee

2013-01-01

Currently radio spectrum is largely managed through Command and Control method. Public mobile services require spectrum below 3 GHz for providing cost effective services. The existing method has created artificial shortage of spectrum especially below 3 GHz. Spectrum trading is a new concept...

Hard Decision Fusion based Cooperative Spectrum Sensing in Cognitive Radio System

Directory of Open Access Journals (Sweden)

N. Armi N.M. Saad

2013-09-01

Full Text Available Cooperative spectrum sensing was proposed to combat fading, noise uncertainty, shadowing, and even hidden node problem due to primary users (PUs activity that is not spatially localized. It improves the probability of detection by collaborating to detect PUs signal in cognitive radio (CR system as well. This paper studies cooperative spectrum sensing and signal detection in CR system by implementing hard decision combining in data fusion centre. Through computer simulation, we evaluate the performances of cooperative spectrum sensing and signal detection by employing OR and AND rules as decision combining. Energy detector is used to observe the presence of primary user (PU signal. Those results are compared to non-cooperative signal detection for evaluation. They show that cooperative technique has better performance than non-cooperative. Moreover, signal to noise ratio (SNR with greater than or equal 10 dB and 15 collaborated users in CR system has optimal value for probability of detection.

p16 mutation spectrum in the premalignant condition Barrett's esophagus.

Directory of Open Access Journals (Sweden)

Thomas G Paulson

Full Text Available BACKGROUND: Mutation, promoter hypermethylation and loss of heterozygosity involving the tumor suppressor gene p16 (CDKN2a/INK4a have been detected in a wide variety of human cancers, but much less is known concerning the frequency and spectrum of p16 mutations in premalignant conditions. METHODS AND FINDINGS: We have determined the p16 mutation spectrum for a cohort of 304 patients with Barrett's esophagus, a premalignant condition that predisposes to the development of esophageal adenocarcinoma. Forty seven mutations were detected by sequencing of p16 exon 2 in 44 BE patients (14.5% with a mutation spectrum consistent with that caused by oxidative damage and chronic inflammation. The percentage of patients with p16 mutations increased with increasing histologic grade. In addition, samples from 3 out of 19 patients (15.8% who underwent esophagectomy were found to have mutations. CONCLUSIONS: The results of this study suggest the environment of the esophagus in BE patients can both generate and select for clones with p16 mutations.

Spectrum Graph Coloring and Applications to Wi-Fi Channel Assignment

Directory of Open Access Journals (Sweden)

David Orden

2018-03-01

Full Text Available We introduce and explore a family of vertex-coloring problems, which, surprisingly enough, have not been considered before despite stemming from the problem of Wi-Fi channel assignment. Given a spectrum of colors, endowed with a matrix of interferences between each pair of colors, the Threshold Spectrum Coloring problem fixes the number of colors available and aims to minimize the interference threshold, i.e., the maximum of the interferences at the vertices. Conversely, the Chromatic Spectrum Coloring problem fixes a threshold and aims to minimize the number of colors for which respecting that threshold is possible. As the main theoretical results, we prove tight upper bounds for the solutions to each problem. Since both problems turn out to be NP-hard, we complete the scene with experimental results. We propose a DSATUR-based heuristic and study its performance to minimize the maximum vertex interference in Wi-Fi channel assignment, both for randomly-generated graphs and for a real-world scenario. Further, for all these graphs, we experimentally check the goodness of the theoretical bounds.

SpecNet: Spectrum Sensing Sans Frontieres

OpenAIRE

Iyer, Anand Padmanabha; Chintalapudi, Krishna; Navda, Vishnu; Ramjee, Ramachandran; Padmanabhan, Venkata N; Murthy, Chandra R

2011-01-01

While the under-utilization of licensed spectrum based on measurement studies conducted in a few developed countries has spurred lots of interest in opportunistic spectrum access, there exists no infrastructure today for measuring real-time spectrum occupancy across vast geographical regions. In this paper, we present the design and implementation of SpecNet, a first-of-its-kind platform that allows spectrum analyzers around the world to be networked and efficiently used in a coordinated manner...

A simplified multisupport response spectrum method

Science.gov (United States)

Ye, Jihong; Zhang, Zhiqiang; Liu, Xianming

2012-03-01

A simplified multisupport response spectrum method is presented. The structural response is a sum of two components of a structure with a first natural period less than 2 s. The first component is the pseudostatic response caused by the inconsistent motions of the structural supports, and the second is the structural dynamic response to ground motion accelerations. This method is formally consistent with the classical response spectrum method, and the effects of multisupport excitation are considered for any modal response spectrum or modal superposition. If the seismic inputs at each support are the same, the support displacements caused by the pseudostatic response become rigid body displacements. The response spectrum in the case of multisupport excitations then reduces to that for uniform excitations. In other words, this multisupport response spectrum method is a modification and extension of the existing response spectrum method under uniform excitation. Moreover, most of the coherency coefficients in this formulation are simplified by approximating the ground motion excitation as white noise. The results indicate that this simplification can reduce the calculation time while maintaining accuracy. Furthermore, the internal forces obtained by the multisupport response spectrum method are compared with those produced by the traditional response spectrum method in two case studies of existing long-span structures. Because the effects of inconsistent support displacements are not considered in the traditional response spectrum method, the values of internal forces near the supports are underestimated. These regions are important potential failure points and deserve special attention in the seismic design of reticulated structures.

Research on the correlation between corona current spectrum and audible noise spectrum of HVDC transmission line

Science.gov (United States)

Liu, Yingyi; Zhou, Lijuan; Liu, Yuanqing; Yuan, Haiwen; Ji, Liang

2017-11-01

Audible noise is closely related to corona current on a high voltage direct current (HVDC) transmission line. In this paper, we measured a large amount of audible noise and corona current waveforms simultaneously based on the largest outdoor HVDC corona cage all over the world. By analyzing the experimental data, the related statistical regularities between a corona current spectrum and an audible noise spectrum were obtained. Furthermore, the generation mechanism of audible noise was analyzed theoretically, and the related mathematical expression between the audible noise spectrum and the corona current spectrum, which is suitable for all of these measuring points in the space, has been established based on the electro-acoustic conversion theory. Finally, combined with the obtained mathematical relation, the internal reasons for these statistical regularities appearing in measured corona current and audible noise data were explained. The results of this paper not only present the statistical association regularities between the corona current spectrum and the audible noise spectrum on a HVDC transmission line, but also reveal the inherent reasons of these associated rules.

When the Child is Suspected to Have Autism Spectrum Disorder: Recommendation for Parents

Directory of Open Access Journals (Sweden)

Borodina L.G.

2015-12-01

Full Text Available Experts in the area of treatment and intervention for autism spectrum disorders provide parents with recommenda¬tions for situations when their children are suspected to have autism or have been diagnosed. These recommenda¬tions are universal and are appropriate for raising a child with any spectrum disorder. Following these recommenda¬tions will allow parents to comprehend the situation with the child’s development, access approaches, that are used by professionals, and will help them to not waste precious time on finding primary information after the diagnosis.

Can the tinnitus spectrum identify tinnitus subgroups?

NARCIS (Netherlands)

Heijneman, Karin M.; de Kleine, Emile; Wiersinga-Post, Esther; van Dijk, Pim

2013-01-01

The tinnitus spectrum is a psycho-acoustic metric of tinnitus. Previous work found a tight relation between the spectrum and the tone audiogram. This suggests that the spectrum and the audiogram provide essentially the same information, and the added value of the spectrum is limited. In order to

Theory of mind in children with and without autism spectrum disorder: Associations with the sibling constellation.

Science.gov (United States)

Matthews, Nicole L; Goldberg, Wendy A

2018-04-01

The two prior studies that have examined associations between the sibling constellation and theory of mind in autism spectrum disorder yielded discrepant findings. Thus, efforts to better understand the sibling-theory of mind link in autism spectrum disorder are necessary. This study examined a sample of prekindergarten- and kindergarten-aged (i.e. 4-6 years) typically developing children ( n = 39) and verbal children with autism spectrum disorder ( n = 61). Sibling presence, number of siblings, and having younger and older siblings were positively associated with theory of mind in typically developing children, but not in the full sample of children with autism spectrum disorder. However, in the subgroup of children with autism spectrum disorder without sibling recurrence, the presence of at least one older sibling was positively associated with theory of mind. Findings expand previous limited research on the sibling-theory of mind link in children with autism spectrum disorder by demonstrating a potential difference in the influence of the sibling constellation between children from simplex and multiplex families.

Gamma-ray pulse height spectrum analysis on systems with multiple Ge detectors using spectrum summing

Energy Technology Data Exchange (ETDEWEB)

Killian, E.W. [Idaho National Engineering Lab., Idaho Falls, ID (United States)

1997-11-01

A technique has been developed at the Idaho National Engineering Laboratory to sum high resolution gamma-ray pulse spectra from systems with multiple Ge detectors. Lockheed Martin Idaho Technologies Company operates a multi-detector spectrometer configuration at the Stored Waste Examination Pilot Plant facility which is used to characterize the radionuclide contents in waste drums destined for shipment to Waste Isolation Pilot Plant. This summing technique was developed to increase the sensitivity of the system, reduce the count times required to properly quantify the radio-nuclides and provide a more consistent methodology for combining data collected from multiple detectors. In spectrometer systems with multiple detectors looking at non homogeneous waste forms it is often difficult to combine individual spectrum analysis results from each detector to obtain a meaningful result for the total waste container. This is particularly true when the counting statistics in each individual spectrum are poor. The spectrum summing technique adds the spectra collected by each detector into a single spectrum which has better counting statistics than each individual spectrum. A normal spectral analysis program can then be used to analyze the sum spectrum to obtain radio-nuclide values which have smaller errors and do not have to be further manipulated to obtain results for the total waste container. 2 refs., 2 figs.

Volume dependence of light hadron masses in full lattice QCD

Energy Technology Data Exchange (ETDEWEB)

Orth, B.; Lippert, T.; Schilling, K

2004-03-01

The aim of the GRAL project is to simulate full QCD with standard Wilson fermions at light quark masses on small to medium-sized lattices and to obtain infinite-volume results by extrapolation. In order to establish the functional form of the volume dependence we study systematically the finite-size effects in the light hadron spectrum. We give an update on the status of the GRAL project and show that our simulation data for the light hadron masses depend exponentially on the lattice size.

Full Color Camouflage in a Printable Photonic Blue-Colored Polymer

OpenAIRE

Moirangthem, Monali; Schenning, Albertus P. H. J.

2018-01-01

A blue reflective photonic polymer coating which can be patterned in full color, from blue to red, by printing with an aqueous calcium nitrate solution has been fabricated. Color change in the cholesteric liquid-crystalline polymer network over the entire visible spectrum is obtained by the use of nonreactive mesogen. The pattern in the coating is hidden in the blue color dry state and appears upon exposure to water or by exhaling breath onto it due to different degrees of swelling of the pol...

Volume dependence of light hadron masses in full lattice QCD

International Nuclear Information System (INIS)

Orth, B.; Lippert, T.; Schilling, K.

2004-01-01

The aim of the GRAL project is to simulate full QCD with standard Wilson fermions at light quark masses on small to medium-sized lattices and to obtain infinite-volume results by extrapolation. In order to establish the functional form of the volume dependence we study systematically the finite-size effects in the light hadron spectrum. We give an update on the status of the GRAL project and show that our simulation data for the light hadron masses depend exponentially on the lattice size

Full-Band Quasi-Harmonic Analysis and Synthesis of Musical Instrument Sounds with Adaptive Sinusoids

Directory of Open Access Journals (Sweden)

Marcelo Caetano

2016-05-01

Full Text Available Sinusoids are widely used to represent the oscillatory modes of musical instrument sounds in both analysis and synthesis. However, musical instrument sounds feature transients and instrumental noise that are poorly modeled with quasi-stationary sinusoids, requiring spectral decomposition and further dedicated modeling. In this work, we propose a full-band representation that fits sinusoids across the entire spectrum. We use the extended adaptive Quasi-Harmonic Model (eaQHM to iteratively estimate amplitude- and frequency-modulated (AM–FM sinusoids able to capture challenging features such as sharp attacks, transients, and instrumental noise. We use the signal-to-reconstruction-error ratio (SRER as the objective measure for the analysis and synthesis of 89 musical instrument sounds from different instrumental families. We compare against quasi-stationary sinusoids and exponentially damped sinusoids. First, we show that the SRER increases with adaptation in eaQHM. Then, we show that full-band modeling with eaQHM captures partials at the higher frequency end of the spectrum that are neglected by spectral decomposition. Finally, we demonstrate that a frame size equal to three periods of the fundamental frequency results in the highest SRER with AM–FM sinusoids from eaQHM. A listening test confirmed that the musical instrument sounds resynthesized from full-band analysis with eaQHM are virtually perceptually indistinguishable from the original recordings.

Multislot Simultaneous Spectrum Sensing and Energy Harvesting in Cognitive Radio

Directory of Open Access Journals (Sweden)

Xin Liu

2016-07-01

Full Text Available In cognitive radio (CR, the spectrum sensing of the primary user (PU may consume some electrical power from the battery capacity of the secondary user (SU, resulting in a decrease in the transmission power of the SU. In this paper, a multislot simultaneous spectrum sensing and energy harvesting model is proposed, which uses the harvested radio frequency (RF energy of the PU signal to supply the spectrum sensing. In the proposed model, the sensing duration is divided into multiple sensing slots consisting of one local-sensing subslot and one energy-harvesting subslot. If the PU is detected to be present in the local-sensing subslot, the SU will harvest RF energy of the PU signal in the energy-harvesting slot, otherwise, the SU will continue spectrum sensing. The global decision on the presence of the PU is obtained through combining local sensing results from all the sensing slots by adopting “Or-logic Rule”. A joint optimization problem of sensing time and time splitter factor is proposed to maximize the throughput of the SU under the constraints of probabilities of false alarm and detection and energy harvesting. The simulation results have shown that the proposed model can clearly improve the maximal throughput of the SU compared to the traditional sensing-throughput tradeoff model.

On the Energy Spectrum of Strong Magnetohydrodynamic Turbulence

Directory of Open Access Journals (Sweden)

Jean Carlos Perez

2012-10-01

Full Text Available The energy spectrum of magnetohydrodynamic turbulence attracts interest due to its fundamental importance and its relevance for interpreting astrophysical data. Here we present measurements of the energy spectra from a series of high-resolution direct numerical simulations of magnetohydrodynamics turbulence with a strong guide field and for increasing Reynolds number. The presented simulations, with numerical resolutions up to 2048^{3} mesh points and statistics accumulated over 30 to 150 eddy turnover times, constitute, to the best of our knowledge, the largest statistical sample of steady state magnetohydrodynamics turbulence to date. We study both the balanced case, where the energies associated with Alfvén modes propagating in opposite directions along the guide field, E^{+}(k_{⊥} and E^{-}(k_{⊥}, are equal, and the imbalanced case where the energies are different. In the balanced case, we find that the energy spectrum converges to a power law with exponent -3/2 as the Reynolds number is increased, which is consistent with phenomenological models that include scale-dependent dynamic alignment. For the imbalanced case, with E^{+}>E^{-}, the simulations show that E^{-}∝k_{⊥}^{-3/2} for all Reynolds numbers considered, while E^{+} has a slightly steeper spectrum at small Re. As the Reynolds number increases, E^{+} flattens. Since E^{±} are pinned at the dissipation scale and anchored at the driving scales, we postulate that at sufficiently high Re the spectra will become parallel in the inertial range and scale as E^{+}∝E^{-}∝k_{⊥}^{-3/2}. Questions regarding the universality of the spectrum and the value of the “Kolmogorov constant” are discussed.

Urinary tract infection in full-term newborn infants: risk factor analysis

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Falcão Mário Cícero

2000-01-01

Full Text Available OBJECTIVE: To analyze the correlation of risk factors to the occurrence of urinary tract infection in full-term newborn infants. PATIENTS AND METHODS: Retrospective study (1997 including full-term infants having a positive urine culture by bag specimen. Urine collection was based on: fever, weight loss > 10% of birth weight, nonspecific symptoms (feeding intolerance, failure to thrive, hypoactivity, debilitate suction, irritability, or renal and urinary tract malformations. In these cases, another urine culture by suprapubic bladder aspiration was collected to confirm the diagnosis. To compare and validate the risk factors in each group, the selected cases were divided into two groups: Group I - positive urine culture by bag specimen collection and negative urine culture by suprapubic aspiration, and Group II - positive urine culture by bag specimen collection and positive urine culture by suprapubic aspiration . RESULTS: Sixty one infants were studied, Group I, n = 42 (68.9% and Group II, n = 19 (31.1%. The selected risk factors (associated infectious diseases, use of broad-spectrum antibiotics, renal and urinary tract malformations, mechanical ventilation, parenteral nutrition and intravascular catheter were more frequent in Group II (p<0.05. Through relative risk analysis, risk factors were, in decreasing importance: parenteral nutrition, intravascular catheter, associated infectious diseases, use of broad-spectrum antibiotics, mechanical ventilation, and renal and urinary tract malformations. CONCLUSION: The results showed that parenteral nutrition, intravascular catheter, and associated infectious diseases contributed to increase the frequency of neonatal urinary tract infection, and in the presence of more than one risk factor, the occurrence of urinary tract infection rose up to 11 times.

Spectrum of resistivity gradient driven turbulence

International Nuclear Information System (INIS)

Terry, P.W.; Diamond, P.H.; Shaing, K.C.; Garcia, L.; Carreras, B.A.

1986-01-01

The resistivity fluctuation correlation function and electrostatic potential spectrum of resistivity gradient driven turbulence are calculated analytically and compared to the results of three dimensional numerical calculations. Resistivity gradient driven turbulence is characterized by effective Reynolds' numbers of order unity. Steady-state solution of the renormalized spectrum equations yields an electrostatic potential spectrum (circumflex phi 2 )/sub ktheta/ approx. k/sub theta//sup -3.25/. Agreement of the analytically calculated potential spectrum and mean-square radial velocity with the results of multiple helicity numerical calculations is excellent. This comparison constitutes a quantitative test of the analytical turbulence theory used. The spectrum of magnetic fluctuations is also calculated, and agrees well with that obtained from the numerical computations. 13 refs., 8 figs

Multiagent Reinforcement Learning Dynamic Spectrum Access in Cognitive Radios

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Wu Chun

2014-02-01

Full Text Available A multiuser independent Q-learning method which does not need information interaction is proposed for multiuser dynamic spectrum accessing in cognitive radios. The method adopts self-learning paradigm, in which each CR user performs reinforcement learning only through observing individual performance reward without spending communication resource on information interaction with others. The reward is defined suitably to present channel quality and channel conflict status. The learning strategy of sufficient exploration, preference for good channel, and punishment for channel conflict is designed to implement multiuser dynamic spectrum accessing. In two users two channels scenario, a fast learning algorithm is proposed and the convergence to maximal whole reward is proved. The simulation results show that, with the proposed method, the CR system can obtain convergence of Nash equilibrium with large probability and achieve great performance of whole reward.

An Energy-Efficient Game-Theory-Based Spectrum Decision Scheme for Cognitive Radio Sensor Networks

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Shelly Salim

2016-06-01

Full Text Available A cognitive radio sensor network (CRSN is a wireless sensor network in which sensor nodes are equipped with cognitive radio. In this paper, we propose an energy-efficient game-theory-based spectrum decision (EGSD scheme for CRSNs to prolong the network lifetime. Note that energy efficiency is the most important design consideration in CRSNs because it determines the network lifetime. The central part of the EGSD scheme consists of two spectrum selection algorithms: random selection and game-theory-based selection. The EGSD scheme also includes a clustering algorithm, spectrum characterization with a Markov chain, and cluster member coordination. Our performance study shows that EGSD outperforms the existing popular framework in terms of network lifetime and coordination overhead.

Autism Spectrum Disorders

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Rebecca E. Rosenberg

2011-01-01

Full Text Available We used a national online registry to examine variation in cumulative prevalence of community diagnosis of psychiatric comorbidity in 4343 children with autism spectrum disorders (ASD. Adjusted multivariate logistic regression models compared influence of individual, family, and geographic factors on cumulative prevalence of parent-reported anxiety disorder, depression, bipolar disorder, and attention deficit/hyperactivity disorder or attention deficit disorder. Adjusted odds of community-assigned lifetime psychiatric comorbidity were significantly higher with each additional year of life, with increasing autism severity, and with Asperger syndrome and pervasive developmental disorder—not otherwise specified compared with autistic disorder. Overall, in this largest study of parent-reported community diagnoses of psychiatric comorbidity, gender, autistic regression, autism severity, and type of ASD all emerged as significant factors correlating with cumulative prevalence. These findings could suggest both underlying trends in actual comorbidity as well as variation in community interpretation and application of comorbid diagnoses in ASD.

Sparse coding of the modulation spectrum for noise-robust automatic speech recognition

NARCIS (Netherlands)

Ahmadi, S.; Ahadi, S.M.; Cranen, B.; Boves, L.W.J.

2014-01-01

The full modulation spectrum is a high-dimensional representation of one-dimensional audio signals. Most previous research in automatic speech recognition converted this very rich representation into the equivalent of a sequence of short-time power spectra, mainly to simplify the computation of the

Disrupted Cortical Connectivity as an Explanatory Model for Autism Spectrum Disorder

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Jenniefer Drude Borup

2014-02-01

Full Text Available The aim of this article is to explain the theory of Disrupted Cortical Connectivity and discuss whether or not it can integrate the following three theories: Theory of Mind, Executive Functioning, and Weak Central Coherence that dominate the field of autism spectrum disorder research. Due to a lack of existing literature discussing this potential integration, we have consequentially undertaken such an endeavour. In our opinion, integration appears to be possible since this explanatory model can account for difficulties in both social cognition and executive functioning commonly found in autism spectrum disorder. Moreover, the theory of Disrupted Cortical Connectivity could be described as an extension of the theory of Weak Central Coherence.

Dual-Source Swept-Source Optical Coherence Tomography Reconstructed on Integrated Spectrum

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Shoude Chang

2012-01-01

Full Text Available Dual-source swept-source optical coherence tomography (DS-SSOCT has two individual sources with different central wavelengths, linewidth, and bandwidths. Because of the difference between the two sources, the individually reconstructed tomograms from each source have different aspect ratio, which makes the comparison and integration difficult. We report a method to merge two sets of DS-SSOCT raw data in a common spectrum, on which both data have the same spectrum density and a correct separation. The reconstructed tomographic image can seamlessly integrate the two bands of OCT data together. The final image has higher axial resolution and richer spectroscopic information than any of the individually reconstructed tomography image.

Correlation of Social Network Attributes with Individuals’ Score on Bipolar Spectrum Diagnostic Scale

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Amir Momeni Boroujeni

2012-12-01

Full Text Available Bipolar Spectrum Disorders include a variety of mood disorders from bipolar II disorder to conditions characterized by hyperthymic mood states. It has been suggested that psychosocial factors also play an important role in bipolar disorders, in this study we have used social network analysis in order to better understand the social positions of those affected by bipolar spectrum disorders.Methods and Materials: In this cross sectional study 90 individuals within a bounded network were included and studied by using a standard questionnaire for bipolar spectrum disorder scale (BSDS and a sociometric questionnaire for analyzing the social network of those individuals.Results: This study showed that BSDS score is significantly correlated with the Bonacich power of the participants (P= 0.009 as well as with their Outdegree Strength (P= 0.013.Discussion:The results of this study show that there is interplay between social attributes and Bipolar Spectrum Disorders. This emphasizes the need for understanding the role of social networks and performing further research into quantifying social aspects of psychiatric disorders.

Correlation of Social Network Attributes with Individuals’ Score on Bipolar Spectrum Diagnostic Scale

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Amir Momeni Boroujeni

2012-09-01

Full Text Available Introduction: Bipolar Spectrum Disorders include a variety of mood disorders from bipolar II disorder to conditions characterized by hyperthymic mood states. It has been suggested that psychosocial factors also play an important role in bipolar disorders, in this study we have used social network analysis in order to better understand the social positions of those affected by bipolar spectrum disorders. Methods: In this cross sectional study 90 individuals within a bounded network were included and studied by using a standard questionnaire for bipolar spectrum disorder scale (BSDS and a sociometric questionnaire for analyzing the social network of those individuals.Results: This study showed that BSDS score is signi.cantly correlated with the Bonacich power of the participants (P= 0.009 as well as with their Outdegree Strength (P= 0.013.Discussion: The results of this study show that there is interplay between social attributes and Bipolar Spectrum Disorders. This emphasizes the need for understanding the role of social networks and performing further research into quantifying social aspects of psychiatric disorders.

Spectrum Sharing Based on a Bertrand Game in Cognitive Radio Sensor Networks

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Biqing Zeng

2017-01-01

Full Text Available In the study of power control and allocation based on pricing, the utility of secondary users is usually studied from the perspective of the signal to noise ratio. The study of secondary user utility from the perspective of communication demand can not only promote the secondary users to meet the maximum communication needs, but also to maximize the utilization of spectrum resources, however, research in this area is lacking, so from the viewpoint of meeting the demand of network communication, this paper designs a two stage model to solve spectrum leasing and allocation problem in cognitive radio sensor networks (CRSNs. In the first stage, the secondary base station collects the secondary network communication requirements, and rents spectrum resources from several primary base stations using the Bertrand game to model the transaction behavior of the primary base station and secondary base station. The second stage, the subcarriers and power allocation problem of secondary base stations is defined as a nonlinear programming problem to be solved based on Nash bargaining. The simulation results show that the proposed model can satisfy the communication requirements of each user in a fair and efficient way compared to other spectrum sharing schemes.

A Robust FLOM Based Spectrum Sensing Scheme under Middleton Class A Noise in IoT

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Enwei Xu

2017-01-01

Full Text Available Accessibility to remote users in dynamic environment, high spectrum utilization, and no spectrum purchase make Cognitive Radio (CR a feasible solution of wireless communications in the Internet of Things (IoT. Reliable spectrum sensing becomes the prerequisite for the establishment of communication between IoT-capable objects. Considering the application environment, spectrum sensing not only has to cope with man-made impulsive noises but also needs to overcome noise fluctuations. In this paper, we study the Fractional Lower Order Moments (FLOM based spectrum sensing method under Middleton Class A noise and incorporate a Noise Power Estimation (NPE module into the sensing system to deal with the issue of noise uncertainty. Moreover, the NPE process does not need noise-only samples. The analytical expressions of the probabilities of detection and the probability of false alarm are derived. The impact on sensing performance of the parameters of the NPE module is also analyzed. The theoretical analysis and simulation results show that our proposed sensing method achieves a satisfactory performance at low SNR.

Spectrum of Discrete Second-Order Difference Operator with Sign-Changing Weight and Its Applications

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Ruyun Ma

2014-01-01

Full Text Available Let T>1 be an integer, and let=1,2,…,T. We discuss the spectrum of discrete linear second-order eigenvalue problems Δ2ut-1+λmtut=0, t∈,  u0=uT+1=0, where λ≠0 is a parameter, m:→ℝ changes sign and mt≠0 on . At last, as an application of this spectrum result, we show the existence of sign-changing solutions of discrete nonlinear second-order problems by using bifurcate technique.

Primordial power spectrum features and consequences

Science.gov (United States)

Goswami, G.

2014-03-01

The present Cosmic Microwave Background (CMB) temperature and polarization anisotropy data is consistent with not only a power law scalar primordial power spectrum (PPS) with a small running but also with the scalar PPS having very sharp features. This has motivated inflationary models with such sharp features. Recently, even the possibility of having nulls in the power spectrum (at certain scales) has been considered. The existence of these nulls has been shown in linear perturbation theory. What shall be the effect of higher order corrections on such nulls? Inspired by this question, we have attempted to calculate quantum radiative corrections to the Fourier transform of the 2-point function in a toy field theory and address the issue of how these corrections to the power spectrum behave in models in which the tree-level power spectrum has a sharp dip (but not a null). In particular, we have considered the possibility of the relative enhancement of radiative corrections in a model in which the tree-level spectrum goes through a dip in power at a certain scale. The mode functions of the field (whose power spectrum is to be evaluated) are chosen such that they undergo the kind of dynamics that leads to a sharp dip in the tree level power spectrum. Next, we have considered the situation in which this field has quartic self interactions, and found one loop correction in a suitably chosen renormalization scheme. Thus, we have attempted to answer the following key question in the context of this toy model (which is as important in the realistic case): In the chosen renormalization scheme, can quantum radiative corrections be enhanced relative to tree-level power spectrum at scales, at which sharp dips appear in the tree-level spectrum?

Justification for the development of a bending magnet beamline at sector 10 at the APS

International Nuclear Information System (INIS)

Kemner, K. M.; Biosciences Division

2006-01-01

The long-planned and much-needed merger of EnviroCAT into the Materials Research Collaborative Access Team (MR-CAT) will provide dedicated state-of-the-art facilities that are critical to research on a broad range of issues in environmental sciences. These CATs will focus on developing a bending magnet (BM) beamline for x-ray absorption fine structure (XAFS) and micro x-ray analysis of environmental samples through integration with existing insertion device (ID) capabilities in XAFS, micro x-ray analysis, and x-ray scattering. In addition, the expanded MR-CAT will serve as the hub of personnel and laboratory infrastructure support for molecular environmental science and biogeochemical science at the Advanced Photon Source (APS). In conjunction with the merger of EnviroCAT into MR-CAT, the US Environmental Protection Agency (EPA) will become a member institution of MR-CAT, joining the present members (University of Notre Dame, Illinois Institute of Technology, University of Florida, British Petroleum, and Argonne's Chemical Engineering and Biosciences Division). The motivation for blending capabilities meeting the needs of EnviroCAT users into the MR-CAT facilities is the explosion of synchrotron-radiation-based research in the field known as molecular environmental science (MES). This research is driven largely by the need to remediate contaminated environmental materials and to understand the scientific foundations that govern contaminant transport in the environment. Synchrotron radiation is playing a crucial role in solving environmental science problems by offering x-ray-based analytical techniques for detailed molecular- and atomic-level studies of these systems. This document focuses on the scientific justification for developing a specific type of BM beamline capability at Sector 10 for XAFS and micro x-ray analysis to support the growing MES community. However, the modification of Sector 10 will meet other future needs by providing (1) an existing undulator

Justification for the development of a bending magnet beamline at sector 10 at the APS.

Energy Technology Data Exchange (ETDEWEB)

Kemner, K. M.; Biosciences Division

2006-09-18

The long-planned and much-needed merger of EnviroCAT into the Materials Research Collaborative Access Team (MR-CAT) will provide dedicated state-of-the-art facilities that are critical to research on a broad range of issues in environmental sciences. These CATs will focus on developing a bending magnet (BM) beamline for x-ray absorption fine structure (XAFS) and micro x-ray analysis of environmental samples through integration with existing insertion device (ID) capabilities in XAFS, micro x-ray analysis, and x-ray scattering. In addition, the expanded MR-CAT will serve as the hub of personnel and laboratory infrastructure support for molecular environmental science and biogeochemical science at the Advanced Photon Source (APS). In conjunction with the merger of EnviroCAT into MR-CAT, the US Environmental Protection Agency (EPA) will become a member institution of MR-CAT, joining the present members (University of Notre Dame, Illinois Institute of Technology, University of Florida, British Petroleum, and Argonne's Chemical Engineering and Biosciences Division). The motivation for blending capabilities meeting the needs of EnviroCAT users into the MR-CAT facilities is the explosion of synchrotron-radiation-based research in the field known as molecular environmental science (MES). This research is driven largely by the need to remediate contaminated environmental materials and to understand the scientific foundations that govern contaminant transport in the environment. Synchrotron radiation is playing a crucial role in solving environmental science problems by offering x-ray-based analytical techniques for detailed molecular- and atomic-level studies of these systems. This document focuses on the scientific justification for developing a specific type of BM beamline capability at Sector 10 for XAFS and micro x-ray analysis to support the growing MES community. However, the modification of Sector 10 will meet other future needs by providing (1) an existing

Neutron spectrum unfolding: Pt. 2

International Nuclear Information System (INIS)

Matiullah; Wiyaja, D.S.; Berzonis, M.A.; Bondars, H.; Lapenas, A.A.; Kudo, K.; Majeed, A.; Durrani, S.A.

1991-01-01

In Part I of this paper, we described the use of the computer code SAIPS in neutron spectrum unfolding. Here in Part II, we present our experimental work carried out to study the shape of the neutron spectrum in different experimental channels of a 5 MW light-water cooled and moderated research reactor. The spectral neutron flux was determined using various fission foils (placed in close contact with mica track detectors) and activation detectors. From the measured activities, the neutron spectrum was unfolded by SAIPS. (author)

Refining Spectrum Fee to Increase Utilization Efficiency by Adopting ITU-R SM 2012-2 Case Study: Cellular Service in Indonesia

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Ismail

2010-05-01

Full Text Available The spectrum fees called as “Biaya Hak Pengguna Frekuensi” (BHP-F for cellular services in Indonesia are currently calculated based on apparatus, proportionally to the number of transceiver stations and radio channels. Unfortunately, the formula cannot promote the efficiency of frequency spectrum efficiency. ITU-R SM 2012-2 recommended the spectrum fee formula that can promote the efficiency; Administrative Incentives Price (AIP also claims to promote the effectiveness of the radio spectrum utilization. By combining ITU-R SM 2012-2 with AIP, the frequency fee formula can promote not only the efficiency but also the effectiveness of spectrum utilization. This paper will explain and discus the modification of ITU-R SM 2012-2 with AIP in designing the spectrum fees for cellular services in Indonesia.

Analysis of the biological spectrum of vascular flora of Ravni Srem flood forests

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Jurišić Branislav

2011-01-01

Full Text Available One of the essential analyses performed during the floristic study of a region is the analysis of the biological spectrum. The analysis of the biological spectrum of the flora includes the determination of the type of life form for each taxon described in the flora of the study region. If it is considered that life form is a specific structural-functional response to the environmental effects and the result of the adaptation during the species evolution, it is clear that the basic characteristics of the site are more or less reflected in any life form. This fact is confirmed by the analysis of the biological spectrum of the flora of Ravni Srem. The analysis of the Ravni Srem flora shows the domination of the hemicryptophytes and the subdomination of the phanerophytes with a considerable participation of the therophytes.

5G Spectrum Sharing

OpenAIRE

Nekovee, Maziar; Rudd, Richard

2017-01-01

In this paper an overview is given of the current status of 5G industry standards, spectrum allocation and use cases, followed by initial investigations of new opportunities for spectrum sharing in 5G using cognitive radio techniques, considering both licensed and unlicensed scenarios. A particular attention is given to sharing millimeter-wave frequencies, which are of prominent importance for 5G.

The mass spectrum of double heavy baryons in new potential quark models

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Kovalenko Vladimir

2017-01-01

Full Text Available A new approach to study the mass spectrum of double heavy baryons (QQ′q containing strange and charmed quarks is proposed. It is based on the separation of variables in the Schrodinger equation in the prolate spheroidal coordinates. Two nonrelativistic potential models are considered. In the first model, the interaction potential of the quarks is the sum of the Coulomb and non-spherically symmetrical linear confinement potential. In the second model it is assumed that the quark confinement provided by a spherically symmetric harmonic oscillator potential. In both models the mass spectrum is calculated, and a comparison with previous results from other models is performed.

Neuromyelitis Optica Spectrum Disorders.

Science.gov (United States)

Akaishi, Tetsuya; Nakashima, Ichiro; Sato, Douglas Kazutoshi; Takahashi, Toshiyuki; Fujihara, Kazuo

2017-05-01

Neuromyelitis optica (NMO) is clinically characterized by severe optic neuritis and transverse myelitis, but recent studies with anti-aquaporin-4-antibody specific to NMO have revealed that the clinical spectrum is wider than previously thought. International consensus diagnostic criteria propose NMO spectrum disorders (NMOSD) as the term to define the entire spectrum including typical NMO, optic neuritis, acute myelitis, brain syndrome, and their combinations. NMOSD is now divided into anti-aquaporin-4-antibody-seropositive NMOSD and -seronegative NMOSD (or unknown serostatus). MR imaging and optical coherence tomography are indispensable in the diagnosis and evaluation of NMOSD. This article reviews the clinical and MR imaging findings of anti-aquaporin-4-antibody-seropositive and anti-myelin oligodendrocyte glycoprotein-antibody-seropositive NMOSD. Copyright © 2017 Elsevier Inc. All rights reserved.

Combined XRD and XAS

International Nuclear Information System (INIS)

Ehrlich, S.N.; Hanson, J.C.; Lopez Camara, A.; Barrio, L.; Estrella, M.; Zhou, G.; Si, R.; Khalid, S.; Wang, Q.

2011-01-01

X-ray diffraction (XRD) and X-ray absorption fine structure (XAFS) are complementary techniques for investigating the structure of materials. XRD probes long range order and XAFS probes short range order. We have combined the two techniques at one synchrotron beamline, X18A at the NSLS, allowing samples to be studied in a single experiment. This beamline will allow for coordinated measurements of local and long range structural changes in chemical transformations and phase transitions using both techniques.

Remote sensing with laser spectrum radar

Science.gov (United States)

Wang, Tianhe; Zhou, Tao; Jia, Xiaodong

2016-10-01

The unmanned airborne (UAV) laser spectrum radar has played a leading role in remote sensing because the transmitter and the receiver are together at laser spectrum radar. The advantages of the integrated transceiver laser spectrum radar is that it can be used in the oil and gas pipeline leak detection patrol line which needs the non-contact reflective detection. The UAV laser spectrum radar can patrol the line and specially detect the swept the area are now in no man's land because most of the oil and gas pipelines are in no man's land. It can save labor costs compared to the manned aircraft and ensure the safety of the pilots. The UAV laser spectrum radar can be also applied in the post disaster relief which detects the gas composition before the firefighters entering the scene of the rescue.

A Collaborative Approach for Monitoring Nodes Behavior during Spectrum Sensing to Mitigate Multiple Attacks in Cognitive Radio Networks

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Mahmoud Khasawneh

2017-01-01

Full Text Available Spectrum sensing is the first step to overcome the spectrum scarcity problem in Cognitive Radio Networks (CRNs wherein all unutilized subbands in the radio environment are explored for better spectrum utilization. Adversary nodes can threaten these spectrum sensing results by launching passive and active attacks that prevent legitimate nodes from using the spectrum efficiently. Securing the spectrum sensing process has become an important issue in CRNs in order to ensure reliable and secure spectrum sensing and fair management of resources. In this paper, a novel collaborative approach during spectrum sensing process is proposed. It monitors the behavior of sensing nodes and identifies the malicious and misbehaving sensing nodes. The proposed approach measures the node’s sensing reliability using a value called belief level. All the sensing nodes are grouped into a specific number of clusters. In each cluster, a sensing node is selected as a cluster head that is responsible for collecting sensing-reputation reports from different cognitive nodes about each node in the same cluster. The cluster head analyzes information to monitor and judge the nodes’ behavior. By simulating the proposed approach, we showed its importance and its efficiency for achieving better spectrum security by mitigating multiple passive and active attacks.

Using near infrared spectrum analysis to predict water and chlorophyll content in tomato leaves

Science.gov (United States)

Jiang, Huanyu; Ying, Yibin; Liu, Yande

2004-11-01

In this study, we developed a nondestructive way to analyze water and chlorophyll content in tomato leaves. A total of 200 leaves were collected as experimental materials, 120 of them were used to form a calibration data set. Drying chest, SPAD meter and NIR spectrometer were used to get water content, chlorophyll content and spectrums of tomato leaves respectively. The Fourier Transform Infrared (FTNIR) method with a smart Near-IR Updrift was used to test spectrums, and partial least squares (PLS) technique was used to analyze the data we get by normal experimentation and near infrared spectrometer, set up a calibration model to predict the leaf water and chlorophyll content based on the characteristics of diffuse reflectance spectrums of tomato leaves. Three different mathematical treatments were used in spectrums processing: different wavelength range, different smoothing points, first and second derivative. We can get best prediction model when we select full range (800-2500nm), 3 points for spectrums smoothing and spectrums by baseline correction, the best model of chlorophyll content has a root mean square error of prediction (RMSEP) of 8.16 and a calibration correlation coefficient (R2) value of 0.89452 and the best model of water content has a root mean square error of prediction (RMSEP) of 0.0214 and a calibration correlation coefficient (R2) value of 0.91043.

Spectrum-to-Spectrum Searching Using a Proteome-wide Spectral Library*

Science.gov (United States)

Yen, Chia-Yu; Houel, Stephane; Ahn, Natalie G.; Old, William M.

2011-01-01

The unambiguous assignment of tandem mass spectra (MS/MS) to peptide sequences remains a key unsolved problem in proteomics. Spectral library search strategies have emerged as a promising alternative for peptide identification, in which MS/MS spectra are directly compared against a reference library of confidently assigned spectra. Two problems relate to library size. First, reference spectral libraries are limited to rediscovery of previously identified peptides and are not applicable to new peptides, because of their incomplete coverage of the human proteome. Second, problems arise when searching a spectral library the size of the entire human proteome. We observed that traditional dot product scoring methods do not scale well with spectral library size, showing reduction in sensitivity when library size is increased. We show that this problem can be addressed by optimizing scoring metrics for spectrum-to-spectrum searches with large spectral libraries. MS/MS spectra for the 1.3 million predicted tryptic peptides in the human proteome are simulated using a kinetic fragmentation model (MassAnalyzer version2.1) to create a proteome-wide simulated spectral library. Searches of the simulated library increase MS/MS assignments by 24% compared with Mascot, when using probabilistic and rank based scoring methods. The proteome-wide coverage of the simulated library leads to 11% increase in unique peptide assignments, compared with parallel searches of a reference spectral library. Further improvement is attained when reference spectra and simulated spectra are combined into a hybrid spectral library, yielding 52% increased MS/MS assignments compared with Mascot searches. Our study demonstrates the advantages of using probabilistic and rank based scores to improve performance of spectrum-to-spectrum search strategies. PMID:21532008

Interference Energy Spectrum of the Infinite Square Well

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Mordecai Waegell

2016-04-01

Full Text Available Certain superposition states of the 1-D infinite square well have transient zeros at locations other than the nodes of the eigenstates that comprise them. It is shown that if an infinite potential barrier is suddenly raised at some or all of these zeros, the well can be split into multiple adjacent infinite square wells without affecting the wavefunction. This effects a change of the energy eigenbasis of the state to a basis that does not commute with the original, and a subsequent measurement of the energy now reveals a completely different spectrum, which we call the interference energy spectrum of the state. This name is appropriate because the same splitting procedure applied at the stationary nodes of any eigenstate does not change the measurable energy of the state. Of particular interest, this procedure can result in measurable energies that are greater than the energy of the highest mode in the original superposition, raising questions about the conservation of energy akin to those that have been raised in the study of superoscillations. An analytic derivation is given for the interference spectrum of a given wavefunction Ψ ( x , t with N known zeros located at points s i = ( x i , t i . Numerical simulations were used to verify that a barrier can be rapidly raised at a zero of the wavefunction without significantly affecting it. The interpretation of this result with respect to the conservation of energy and the energy-time uncertainty relation is discussed, and the idea of alternate energy eigenbases is fleshed out. The question of whether or not a preferred discrete energy spectrum is an inherent feature of a particle’s quantum state is examined.

Polysubstance and Behavioral Addictions in a Patient with Bipolar Disorder: Role of Lifetime Subthreshold Autism Spectrum

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Liliana Dell’Osso

2018-01-01

Full Text Available This case report draws attention to the potential relevance of undetected autism spectrum symptoms in a bipolar patient with high work functioning showing a peculiar addictive profile with impulsive and antisocial behaviors. A 23-year-old man with a diagnosis of Bipolar Disorder (BD and Substance Use Disorder (SUD was hospitalized at the Psychiatric Clinic of the University of Pisa for diuretics and β-2 adrenergic agonist abuse in a remission phase of benzodiazepines and substance abuse. He reported a history of behavioral addictions in the framework of a global high work functioning with particular skills in computer science. When assessed for adult autism spectrum symptoms, despite not fulfilling a DSM-5 diagnosis of Autism Spectrum Disorder (ASD, he reported a score of 93/240 at the Ritvo Autism and Asperger Diagnostic Scale (RAADS-r and of 88/160 at the Adult Autism Subthreshold Spectrum (AdAS Spectrum, both indicative of ASD. We argue the possible role of adult subthreshold autism spectrum features, generally disregarded in adult psychiatry, in the peculiar addictive profile developed by this patient with BD that may deserve appropriate treatment.

Quantum Corrected Non-Thermal Radiation Spectrum from the Tunnelling Mechanism

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Subenoy Chakraborty

2015-06-01

Full Text Available The tunnelling mechanism is today considered a popular and widely used method in describing Hawking radiation. However, in relation to black hole (BH emission, this mechanism is mostly used to obtain the Hawking temperature by comparing the probability of emission of an outgoing particle with the Boltzmann factor. On the other hand, Banerjee and Majhi reformulated the tunnelling framework deriving a black body spectrum through the density matrix for the outgoing modes for both the Bose-Einstein distribution and the Fermi-Dirac distribution. In contrast, Parikh and Wilczek introduced a correction term performing an exact calculation of the action for a tunnelling spherically symmetric particle and, as a result, the probability of emission of an outgoing particle corresponds to a non-strictly thermal radiation spectrum. Recently, one of us (C. Corda introduced a BH effective state and was able to obtain a non-strictly black body spectrum from the tunnelling mechanism corresponding to the probability of emission of an outgoing particle found by Parikh and Wilczek. The present work introduces the quantum corrected effective temperature and the corresponding quantum corrected effective metric is written using Hawking’s periodicity arguments. Thus, we obtain further corrections to the non-strictly thermal BH radiation spectrum as the final distributions take into account both the BH dynamical geometry during the emission of the particle and the quantum corrections to the semiclassical Hawking temperature.

Analysis on optical heterodyne frequency error of full-field heterodyne interferometer

Science.gov (United States)

Li, Yang; Zhang, Wenxi; Wu, Zhou; Lv, Xiaoyu; Kong, Xinxin; Guo, Xiaoli

2017-06-01

The full-field heterodyne interferometric measurement technology is beginning better applied by employing low frequency heterodyne acousto-optical modulators instead of complex electro-mechanical scanning devices. The optical element surface could be directly acquired by synchronously detecting the received signal phases of each pixel, because standard matrix detector as CCD and CMOS cameras could be used in heterodyne interferometer. Instead of the traditional four-step phase shifting phase calculating, Fourier spectral analysis method is used for phase extracting which brings lower sensitivity to sources of uncertainty and higher measurement accuracy. In this paper, two types of full-field heterodyne interferometer are described whose advantages and disadvantages are also specified. Heterodyne interferometer has to combine two different frequency beams to produce interference, which brings a variety of optical heterodyne frequency errors. Frequency mixing error and beat frequency error are two different kinds of inescapable heterodyne frequency errors. In this paper, the effects of frequency mixing error to surface measurement are derived. The relationship between the phase extraction accuracy and the errors are calculated. :: The tolerance of the extinction ratio of polarization splitting prism and the signal-to-noise ratio of stray light is given. The error of phase extraction by Fourier analysis that caused by beat frequency shifting is derived and calculated. We also propose an improved phase extraction method based on spectrum correction. An amplitude ratio spectrum correction algorithm with using Hanning window is used to correct the heterodyne signal phase extraction. The simulation results show that this method can effectively suppress the degradation of phase extracting caused by beat frequency error and reduce the measurement uncertainty of full-field heterodyne interferometer.

From passive to active: The spectrum of peace journalism

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Jesse Benn

2015-10-01

Full Text Available One of the biggest hurdles facing the field of peace journalism (PJ is its vague definition. This paper proposes defining PJ as it operates on a spectrum, from passive to active. Through a review of extant PJ literature, this paper synthesizes current theory into an overarching, explicit concept, and calls for it to be further adopted and expanded. To conclude it considers potential advantages, drawbacks, and critiques of its proposal.

Autism Spectrum Disorder and Fragile X Syndrome

Science.gov (United States)

... only after another family member has been diagnosed. Autism Spectrum Disorder and Fragile X Syndrome Fragile X syndrome is ... gene cause of ASD What Is Autism Spectrum Disorder? Autism spectrum disorder (ASD) is a behavioral diagnosis. The range ...

Therapies for Children With Autism Spectrum Disorder

Science.gov (United States)

... With Autism Spectrum Disorder Therapies for Children With Autism Spectrum Disorder Consumer Summary September 23, 2014 Download PDF 692. ... Web page Understanding Your Child's Condition What is autism spectrum disorder (ASD)? ASD includes a range of behavioral symptoms. ...

Wind speed power spectrum analysis for Bushland, Texas

Energy Technology Data Exchange (ETDEWEB)

Eggleston, E.D. [USDA-Agricultural Research Service, Bushland, TX (United States)

1996-12-31

Numerous papers and publications on wind turbulence have referenced the wind speed spectrum presented by Isaac Van der Hoven in his article entitled Power Spectrum of Horizontal Wind Speed Spectrum in the Frequency Range from 0.0007 to 900 Cycles per Hour. Van der Hoven used data measured at different heights between 91 and 125 meters above the ground, and represented the high frequency end of the spectrum with data from the peak hour of hurricane Connie. These facts suggest we should question the use of his power spectrum in the wind industry. During the USDA - Agricultural Research Service`s investigation of wind/diesel system power storage, using the appropriate wind speed power spectrum became a significant issue. We developed a power spectrum from 13 years of hourly average data, 1 year of 5 minute average data, and 2 particularly gusty day`s 1 second average data all collected at a height of 10 meters. While the general shape is similar to the Van der Hoven spectrum, few of his peaks were found in the Bushland spectrum. While higher average wind speeds tend to suggest higher amplitudes in the high frequency end of the spectrum, this is not always true. Also, the high frequency end of the spectrum is not accurately described by simple wind statistics such as standard deviation and turbulence intensity. 2 refs., 5 figs., 1 tab.

An Active Cooperation-Aware Spectrum Allocation Mechanism for Body Sensor Networks

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Fu Jiang

2015-01-01

Full Text Available A cognitive radio-based spectrum allocation scheme using an active cooperative-aware mechanism is proposed in this paper. The scheme ensures that the primary user and secondary users cooperate actively for their own benefits. The primary user releases some spectrum resources to secondary users to actively stimulate them to actively join the cooperative transmission of the primary user, and secondary users help the primary user to relay data in return, as well as its self-data transmission at the same time. The Stackelberg game is used to evenly and jointly optimize the utilities of both the primary and secondary users. Simulation results show that the proposed active cooperation-aware mechanism could improve the body sensor network performance.

Bottomonium spectrum revisited

CERN Document Server

Segovia, Jorge; Entem, David R.; Fernández, Francisco

2016-01-01

We revisit the bottomonium spectrum motivated by the recently exciting experimental progress in the observation of new bottomonium states, both conventional and unconventional. Our framework is a nonrelativistic constituent quark model which has been applied to a wide range of hadronic observables from the light to the heavy quark sector and thus the model parameters are completely constrained. Beyond the spectrum, we provide a large number of electromagnetic, strong and hadronic decays in order to discuss the quark content of the bottomonium states and give more insights about the better way to determine their properties experimentally.

The relationship between sensory processing and anxiety on cars scale in autism spectrum disorder

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Novaković Neda

2015-01-01

Full Text Available Autism Spectrum Disorder is a neurodevelopmental disorder, characterized by deficits in social interactions, social communication, stereotyped behavior associated with sensory disorders occurring before the age of 3. There has been a growing trend of this neurodevelopmental disorder in recent years. Although the sensory processing problems have been noticed since the first descriptions of autism spectrum disorders, it is only the DSM-5, diagnostic and statistical manual of mental disorders, that includes sensory problems, as the crucial symptom in diagnostic profile of autism spectrum disorder. Objective: To establish the relationship between functional areas related to sensory processing and anxiety, as well as to determine the degree of autistic disorder in adolescents and adults with autism spectrum disorder. Method: 42 participants, adolescents and adults with severe autism disorder and intellectual disability, aged 15-35, of both sexes from Belgrade were evaluated by Childhood Autism Rating Scale (CARS used to determine the degree of autistic disorder. The following functional areas were compared: sensory interests and anxiety in adolescents and adults with autistic spectrum of both sexes. Results: The results indicated the existence of the relationship between anxiety and unusual sensory interests and the severity of autism spectrum disorder. The results showed that there was a correlation between visual perception and the level of intellectual functioning, especially of the severity of autistic disorder and visual perception. Conclusion: These results indicate the reasons of the problems and difficulties in the field of general adaptation of the individuals with autism spectrum disorder.

Spectrum Band Selection in Delay-QoS Constrained Cognitive Radio Networks

KAUST Repository

Yang, Yuli

2014-01-01

In this paper, a cognitive radio (CR) network with multiple spectrum bands available for secondary users (SUs) is considered. For the SU\\'s active spectrum-band selection, two criteria are developed. One is to select the band with the highest secondary channel power gain, and the other is to select the band with the lowest interference channel power gain to primary users (PUs). With the quality-of-service (QoS) requirement concerning delay, the effective capacity (EC) behaviors over secondary links are investigated for both criteria under two spectrum-sharing constraints. To begin by presenting full benefits in these criteria, the constraint imposed on the secondary transmitter (ST) is the average interference limitation to PUs only. Furthermore, taking into account the ST\\'s battery/energy budget, the ST is imposed by joint constraints on its average interference to PUs, as well as on its own average transmit power. For either constraint, we formulate the ST\\'s optimal transmit power allocation to maximize the SU\\'s EC with both band-selection criteria and, correspondingly, obtain the secondary\\'s power allocation and maximum EC in closed forms. Numerical results demonstrated subsequently substantiate the validity of our derivations and provide a powerful tool for the spectrum-band selection in CR networks with multiple bands available. © 1967-2012 IEEE.

Measuring light spectrum as a main indicator of artificial sources quality

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Piotr Dąbrowski

2015-05-01

Full Text Available Objective: To compare different artificial light sources in different places where plant breeding is conduced. Methods: Measurements were conducted outdoor, in room, in greenhouse, under four panels with light emitting diodes, in phytotron, in dark room with various light sources and inside Sanyo versatile environmental chamber. The measurements were made by using SpectraPen SP100 (PSI, Czech Republic device. Results: Our result showed that spectrum measured outdoor during sunny day had only one peak at the wavelength of 485 nm (ca. 60000 relative units. On cloudy day, the trend of light spectrum curve was similar, but with lower values. At room conditions, the curve was more flat than outdoor. Under greenhouse conditions, the curve was similar to that measured outdoor. A few additional peaks on the curve appeared by adding high pressure sodium lamp. There were changes of curve under LED panels. Conclusions: It must be underlined that the most similar spectrum curve to daylight light has incandescent bulb and this light source should be preferred as support of daylight in greenhouses and as main source in phytotrons. Using high pressure sodium lamp in greenhouses as support of daylight cause increase in the red/far-red ratio and occurrence of a new peak on spectrum curve. The new possibilities are creating by LED panels with red and blue diodes.

Multicarrier Spread Spectrum Modulation Schemes and Efficient FFT Algorithms for Cognitive Radio Systems

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Mohandass Sundararajan

2014-07-01

Full Text Available Spread spectrum (SS and multicarrier modulation (MCM techniques are recognized as potential candidates for the design of underlay and interweave cognitive radio (CR systems, respectively. Direct Sequence Code Division Multiple Access (DS-CDMA is a spread spectrum technique generally used in underlay CR systems. Orthogonal Frequency Division Multiplexing (OFDM is the basic MCM technique, primarily used in interweave CR systems. There are other MCM schemes derived from OFDM technique, like Non-Contiguous OFDM, Spread OFDM, and OFDM-OQAM, which are more suitable for CR systems. Multicarrier Spread Spectrum Modulation (MCSSM schemes like MC-CDMA, MC-DS-CDMA and SS-MC-CDMA, combine DS-CDMA and OFDM techniques in order to improve the CR system performance and adaptability. This article gives a detailed survey of the various spread spectrum and multicarrier modulation schemes proposed in the literature. Fast Fourier Transform (FFT plays a vital role in all the multicarrier modulation techniques. The FFT part of the modem can be used for spectrum sensing. The performance of the FFT operator plays a crucial role in the overall performance of the system. Since the cognitive radio is an adaptive system, the FFT operator must also be adaptive for various input/output values, in order to save energy and time taken for execution. This article also includes the various efficient FFT algorithms proposed in the literature, which are suitable for CR systems.

Towards classical spectrum generating algebras for f-deformations

Science.gov (United States)

Kullock, Ricardo; Latini, Danilo

2016-01-01

In this paper we revise the classical analog of f-oscillators, a generalization of q-oscillators given in Man'ko et al. (1997) [8], in the framework of classical spectrum generating algebras (SGA) introduced in Kuru and Negro (2008) [9]. We write down the deformed Poisson algebra characterizing the entire family of non-linear oscillators and construct its general solution algebraically. The latter, covering the full range of f-deformations, shows an energy dependence both in the amplitude and the frequency of the motion.

Autism spectrum disorder - childhood disintegrative disorder

Science.gov (United States)

... part of the larger developmental disorder category of autism spectrum disorder . ... American Psychiatric Association. Autism spectrum disorder. ... VA: American Psychiatric Publishing: 2013;50-59. Raviola GJ, ...

Constraints on Particles and Fields from Full Stokes Observations of AGN

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Daniel C. Homan

2018-01-01

Full Text Available Combined polarization imaging of radio jets from Active Galactic Nuclei (AGN in circular and linear polarization, also known as full Stokes imaging, has the potential to constrain both the magnetic field structure and particle properties of jets. Although only a small fraction of the emission when detected, typically less than a few tenths of a percent but up to as much as a couple of percent in the strongest resolved sources, circular polarization directly probes the magnetic field and particles within the jet itself and is not expected to be modified by external screens. A key to using full Stokes observations to constrain jet properties is obtaining a better understanding of the emission of circular polarization, including its variability and spectrum. We discuss what we have learned so far from parsec scale monitoring observations in the MOJAVE program and from multi-frequency observations of selected AGN.

Holographic spectrum-splitting optical systems for solar photovoltaics

Science.gov (United States)

Zhang, Deming

Solar energy is the most abundant source of renewable energy available. The relatively high cost prevents solar photovoltaic (PV) from replacing fossil fuel on a larger scale. In solar PV power generation the cost is reduced with more efficient PV technologies. In this dissertation, methods to improve PV conversion efficiency with holographic optical components are discussed. The tandem multiple-junction approach has achieved very high conversion efficiency. However it is impossible to manufacture tandem PV cells at a low cost due to stringent fabrication standards and limited material types that satisfy lattice compatibility. Current produced by the tandem multi-junction PV cell is limited by the lowest junction due to series connection. Spectrum-splitting is a lateral multi-junction concept that is free of lattice and current matching constraints. Each PV cell can be optimized towards full absorption of a spectral band with tailored light-trapping schemes. Holographic optical components are designed to achieve spectrum-splitting PV energy conversion. The incident solar spectrum is separated onto multiple PV cells that are matched to the corresponding spectral band. Holographic spectrum-splitting can take advantage of existing and future low-cost technologies that produces high efficiency thin-film solar cells. Spectrum-splitting optical systems are designed and analyzed with both transmission and reflection holographic optical components. Prototype holograms are fabricated and high optical efficiency is achieved. Light-trapping in PV cells increases the effective optical path-length in the semiconductor material leading to improved absorption and conversion efficiency. It has been shown that the effective optical path length can be increased by a factor of 4n2 using diffusive surfaces. Ultra-light-trapping can be achieved with optical filters that limit the escape angle of the diffused light. Holographic reflection gratings have been shown to act as angle

Correlation between Substance Use and Anxiety-Depression Spectrum among Senior High School Students in Bandung

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Achmad Samjunanto

2016-12-01

Full Text Available Background: Both substance use and anxiety-depression spectrum are the problem that currently faced by adolescents especially among Senior High School students. Moreover, there is a high comorbidity between both problems. This study was conducted to discover the substance use’s prevalence and to find out anxiety-depression spectrum proportion among adolescent, and more importantly to determine whether there is correlation between both variables. Methods: During October–November 2013, four hundred and fifty two students from five Senior High Schools located in Karees Sub-District, Bandung were included in this cross-sectional analytic study. Among whom, only 425 students filled the questionnaire properly. Data were collected using Kessler-10 (K10 to explore anxiety-depression spectrum and addiction severity index lite version (ASI-Lite to identify substance use. The correlation between both variables was analyzed by Gamma correlation test. Results: The study revealed that there were 93 (21.9% students that used substance. In addition, there were 244 students (57.4% that screened as having anxiety-depression spectrum. Statistical analysis, according to Gamma correlation test, showed that there was a weak correlation between alcohol use and anxiety-depression spectrum (p=0.041; r=0.316. The remaining substances gave no statistically significant result (p>0.05. Conclusions: There is a high prevalence in substance use and psychological distress in anxiety-depression spectrum among high school student. In addition, alcohol is the only substances that correlated with anxiety-depression spectrum.

Electronic structure analysis of UO2 by X-ray absorption spectroscopy

International Nuclear Information System (INIS)

Ozkendir, O.M.

2009-01-01

Full text: Due to the essential role of Actinides in nuclear science and technology, electronic and structural investigations of actinide compounds attract major interest in science. Electronic structure of actinide compounds have important properties due to narrow 5f states which play key role in bonding with anions. The properties of Uranium has been a subject of enduring interest due to its being a major importance as a nuclear fuel and is the highest numbered element which can be found naturally on earth. UO 2 forms as a secondary uranyl group occurred during metamictization of uranium oxide compounds [1].Uranium oxide thin films have been investigated by X-ray Absorption Fine Structure spectroscopy (XAFS) [2]. The full multiple scattering approach has been applied to the calculation of U L3 edge spectra of UO 2 . The calculations are based on different choices of one electron potentials according to Uranium coordinations by using the real space multiple scattering method FEFF 8.2 code [3,4]. U L3-edge absorption spectrum in UO 2 is compared with U L3-edges in USiO 4 and UTe which are chosen due to their different electronic and chemical structures.We have found prominent changes in the XANES spectra of Uranium oxide thin films due to valency properties. Such observed changes are explained by considering the structural, electronic and spectroscopic properties. (author)

Language and communication in autism spectrum disorders

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Vinogradova K.N.

2015-06-01

Full Text Available The present article is a review of English_language literature on the topic of development of language and communication in people with autism spectrum disorders (ASD. It is shown that language in ASD often differs from the one in typical development, particularly in terms of pragmatics, unusual intonation and echolalia, and difficulties in speech perception and comprehension may also be present. Nevertheless, it should be noted that the results of many studies in this area are controversial due to a variety of reasons and it is hardly possible to reach agreement on many questions in this area.

A Novel Dynamic Spectrum Access Framework Based on Reinforcement Learning for Cognitive Radio Sensor Networks

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Yun Lin

2016-10-01

Full Text Available Cognitive radio sensor networks are one of the kinds of application where cognitive techniques can be adopted and have many potential applications, challenges and future research trends. According to the research surveys, dynamic spectrum access is an important and necessary technology for future cognitive sensor networks. Traditional methods of dynamic spectrum access are based on spectrum holes and they have some drawbacks, such as low accessibility and high interruptibility, which negatively affect the transmission performance of the sensor networks. To address this problem, in this paper a new initialization mechanism is proposed to establish a communication link and set up a sensor network without adopting spectrum holes to convey control information. Specifically, firstly a transmission channel model for analyzing the maximum accessible capacity for three different polices in a fading environment is discussed. Secondly, a hybrid spectrum access algorithm based on a reinforcement learning model is proposed for the power allocation problem of both the transmission channel and the control channel. Finally, extensive simulations have been conducted and simulation results show that this new algorithm provides a significant improvement in terms of the tradeoff between the control channel reliability and the efficiency of the transmission channel.

Real time spectrum analysis

International Nuclear Information System (INIS)

Blunden, A.; O'Prey, D.G.; Tait, W.H.

1983-01-01

A method is described for the separation of a composite pulse-height spectrum into its unresolved component parts, which belong to a set of measured library spectra. The method allows real-time estimation giving running estimates during acquisition of the spectrum, minimises computation space, especially for a number of parallel calculations, estimates in advance the rms errors, and produces a significance measure for the hypothesis that the composite contains only the library spectra. Least squares curve-fitting, and other methods, can be compared, with the formalism developed, allowing analytical comparison of the effect of detector energy resolution and detection efficiency. A rational basis for the choice between the various methods of spectrum analysis follows from the theory, minimising rms estimation errors. The method described is applicable for very low numbers of counts and poor resolution. (orig.)

Enabling LTE and WiFi Coexisting in 5 GHz for Efficient Spectrum Utilization

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Hongyu Sun

2017-01-01

Full Text Available Due to the increasing mobile traffic demands in cellular network, researchers have proposed the coexistence of LTE and WiFi technologies in 5 GHz unlicensed bands. Therefore, how to efficiently utilize the spectrum in 5 GHz becomes extremely important. To avoid the channel access conflicts, current LTE Unlicensed (LTE-U technology introduces the duty cycle of LTE, while License-Assisted Access (LAA technology introduces Listen-Before-Talk (LBT mechanism. While these two technologies improve the spectrum utilization by using time division access schema, we believe that more efficient spectrum utilization can be achieved by enabling simultaneous transmissions from LTE and WiFi. In this paper, we propose a novel method (i.e., Low Amplitude Stream Injection (LASI method to enable the simultaneous transmissions of WiFi and LTE frames in the same channel and recover the data from the conflicts. To further utilize the LASI method, we introduce the Conflict-Tolerant Channel Allocation (CTCA algorithm to optimize the channel allocation and achieve more efficient spectrum utilization in 5 GHz. Extensive simulation results show that our approach achieves lower latency and higher throughput. Compared with the state-of-the-art LTE-U and LAA technologies, our approach can improve the spectrum efficiency 2.9 times.

Metasurface optics for full-color computational imaging.

Science.gov (United States)

Colburn, Shane; Zhan, Alan; Majumdar, Arka

2018-02-01

Conventional imaging systems comprise large and expensive optical components that successively mitigate aberrations. Metasurface optics offers a route to miniaturize imaging systems by replacing bulky components with flat and compact implementations. The diffractive nature of these devices, however, induces severe chromatic aberrations, and current multiwavelength and narrowband achromatic metasurfaces cannot support full visible spectrum imaging (400 to 700 nm). We combine principles of both computational imaging and metasurface optics to build a system with a single metalens of numerical aperture ~0.45, which generates in-focus images under white light illumination. Our metalens exhibits a spectrally invariant point spread function that enables computational reconstruction of captured images with a single digital filter. This work connects computational imaging and metasurface optics and demonstrates the capabilities of combining these disciplines by simultaneously reducing aberrations and downsizing imaging systems using simpler optics.

Multi-spectrum and transmit-antenna switched diversity schemes for spectrum sharing systems: A performance analysis

KAUST Repository

Sayed, Mostafa

2012-12-01

In spectrum sharing systems, a secondary user (SU) is allowed to share the spectrum with a primary licensed user under the condition that the interference at the the primary user receiver (PU-Rx) is below a predetermined threshold. Joint primary spectrum and transmit antenna selection diversity schemes can be utilized as an efficient way to meet the quality of service (QoS) demands of the SUs while satisfying the interference constraint. In this paper, we consider a secondary link comprised of a secondary transmitter (SU-Tx) equipped with multiple antennas and a single-antenna secondary receiver (SU-Rx) sharing the same spectrum with a number of primary users (PUs) operating at distinct spectra. We present a performance analysis for two primary spectrum and transmit antenna switched selection schemes with different amount of feedback requirements. In particular, assuming Rayleigh fading and BPSK transmission, we derive approximate BER expressions for the presented schemes. For the sake of comparison, we also derive a closed-form BER expression for the optimal selection scheme that selects the best pair in terms of the SU-Rx signal-to-noise ratio (SNR) which has the disadvantage of high feedback requirements. Finally, our results are verified with numerical simulations. © 2012 IEEE.

Disability Identification and Self-Efficacy among College Students on the Autism Spectrum

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Paul T. Shattuck

2014-01-01

Full Text Available The number of youth on the autism spectrum approaching young adulthood and attending college is growing. Very little is known about the subjective experience of these college students. Disability identification and self-efficacy are two subjective factors that are critical for the developmental and logistical tasks associated with emerging adulthood. This study uses data from the National Longitudinal Transition Study 2 to examine the prevalence and correlates of disability identification and self-efficacy among college students on the autism spectrum. Results indicate nearly one-third of these students do not report seeing themselves as disabled or having a special need. Black race was associated with lower likelihood of both disability identification and self-efficacy.

A Multi-Antenna Framework for Spectrum Reuse Based on Primary-Secondary Cooperation

KAUST Repository

Bakr, Omar; Johnson, Mark; Wild, Ben; Ramchandran, Kannan

2008-01-01

This paper proposes a new framework for spectrum reuse. Existing architectures have centered on secondary users (cognitive radios) that can reliably sense primary users and opportunistically transmit, without directly interacting with the primary system. We present a paradigm in which the primary and secondary systems cooperate, to minimize interference to primary users and provide predictable access for secondary users. Because this architecture gives the primary system full control over spectrum sharing, it could be more favorable in the current economic and political environment. We illustrate a concrete instance of our framework by showing how secondary radios can reuse the entire uplink channel of a cellular network, with only modest changes to the primary infrastructure. ©2008 IEEE.

A Multi-Antenna Framework for Spectrum Reuse Based on Primary-Secondary Cooperation

KAUST Repository

Bakr, Omar

2008-10-01

This paper proposes a new framework for spectrum reuse. Existing architectures have centered on secondary users (cognitive radios) that can reliably sense primary users and opportunistically transmit, without directly interacting with the primary system. We present a paradigm in which the primary and secondary systems cooperate, to minimize interference to primary users and provide predictable access for secondary users. Because this architecture gives the primary system full control over spectrum sharing, it could be more favorable in the current economic and political environment. We illustrate a concrete instance of our framework by showing how secondary radios can reuse the entire uplink channel of a cellular network, with only modest changes to the primary infrastructure. ©2008 IEEE.

The Spectrum of Wind Power Fluctuations

Science.gov (United States)

Bandi, Mahesh

2016-11-01

Wind is a variable energy source whose fluctuations threaten electrical grid stability and complicate dynamical load balancing. The power generated by a wind turbine fluctuates due to the variable wind speed that blows past the turbine. Indeed, the spectrum of wind power fluctuations is widely believed to reflect the Kolmogorov spectrum; both vary with frequency f as f - 5 / 3. This variability decreases when aggregate power fluctuations from geographically distributed wind farms are averaged at the grid via a mechanism known as geographic smoothing. Neither the f - 5 / 3 wind power fluctuation spectrum nor the mechanism of geographic smoothing are understood. In this work, we explain the wind power fluctuation spectrum from the turbine through grid scales. The f - 5 / 3 wind power fluctuation spectrum results from the largest length scales of atmospheric turbulence of order 200 km influencing the small scales where individual turbines operate. This long-range influence spatially couples geographically distributed wind farms and synchronizes farm outputs over a range of frequencies and decreases with increasing inter-farm distance. Consequently, aggregate grid-scale power fluctuations remain correlated, and are smoothed until they reach a limiting f - 7 / 3 spectrum. This work was funded by the Collective Interactions Unit, OIST Graduate University, Japan.

Auction design for the wireless spectrum market

CERN Document Server

Lin, Peng; Zhang, Qian

2014-01-01

This Brief introduces the wireless spectrum market and discusses the current research for spectrum auctions. It covers the unique properties of spectrum auction, such as interference relationship, reusability, divisibility, composite effect and marginal effect, while also proposing how to build economic incentives into the network architecture and protocols in order to optimize the efficiency of wireless systems.Three scenarios for designing new auctions are demonstrated. First, a truthful double auction scheme for spectrum trading considering both the heterogeneous propagation properties of c

Children with autism spectrum disorders and selective mutism

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Steffenburg H

2018-05-01

Full Text Available Hanna Steffenburg, Suzanne Steffenburg, Christopher Gillberg, Eva Billstedt Gillberg Neuropsychiatry Centre, Institute of Neuroscience and Physiology, University of Gothenburg, Sahlgrenska Academy, Gothenburg, Sweden Background: It has been suggested that autism spectrum disorder (ASD might be a “comorbid” condition in selective mutism (SM. Methods: In this retrospective study, we examined medical records of children with SM diagnosis (n=97 at a medical center specializing in assessment of ASD. Results: Mean age for onset of SM symptoms was 4.5 years and mean age at SM diagnosis was 8.8 years. SM was more common among girls (boy:girl ratio=2.7:1. We found that 63% of the study group had an ASD (no gender difference. The SM group with combined ASD had later onset of symptoms, higher age at diagnosis, more often a history of speech delay, and a higher proportion of borderline IQ or intellectual disability.Conclusion: The results highlight the risk of overlap between ASD and SM. Keywords: selective mutism, autism spectrum disorders, Asperger syndrome, autistic disorder

Generation and reception of spread-spectrum signals

Science.gov (United States)

Moser, R.

1983-05-01

The term 'spread-spectrum' implies a technique whereby digitized information is added to a pseudo-random number sequence and the resultant bit stream changes some parameter of the carrier frequency in discrete increments. The discrete modulation of the carrier frequency is usually realized either as a multiple level phase shift keyed or frequency shift keyed signal. The resultant PSK-modulated frequency spectrum is referred to as direct sequence spread-spectrum, whereas the FSK-modulated carrier frequency is referred to as a frequency hopped spread spectrum. These can be considered the major subsets of the more general term 'spread-spectrum'. In discussing signal reception, it is pointed out that active correlation methods are used for channel synchronization when the psuedo random sequences are long or when the processing gain is large, whereas the passive methods may be used for either short pseudo-random noise generation codes or to assist in attaining initial synchronization in long sequence spread-spectrum systems.

Lead Excretion in Spanish Children with Autism Spectrum Disorder

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Milagros Fuentes-Albero

2015-02-01

Full Text Available Among epigenetic factors leading to increased prevalence of juvenile neuropsychiatric disorders, including autism spectrum disorder, exposure to metals, such as lead (Pb have led to conflicting results. The aim of the present study was to determine the levels of Pb in the urine of children with autism spectrum disorder (ASD compared with typically developing children (TD age- and sex-matched, and to analyze any association between core symptoms of ASD, special diets, supplements intake or prescription drugs and the concentration of Pb. The study was performed in a group of children with ASD (n = 35, average age 7.4 ± 0.5 years and TD (n = 34, average age 7.7 ± 0.9 years. Measurement of lead in urine was performed by atomic absorption spectrometry; symptoms of ASD were analyzed by diagnostic and statistical manual of mental disorders (DMS-IV using the questionnary ADI-R. Careful clinical evaluation was also undertaken and statistical analysis was done taking into account any possible confounding factor.

On multiuser switched diversity transmission for spectrum sharing systems

KAUST Repository

Qaraqe, Marwa

2012-01-01

In this paper, we develop multiuser access schemes for spectrum sharing systems whereby secondary users share the spectrum with primary users. In particular, we devise two schemes for selecting the user among those that satisfy the interference constraints and achieve an acceptable signal-to-noise ratio (SNR) level. The first scheme selects the user with the maximum SNR at the receiver, whereas in the second scheme the users are scanned in a sequential manner until an acceptable user is found. In addition, we consider two power adaptive settings. In the on/off power adaptive setting, the users transmit based on whether the interference constraint is met or not while in the full power adaptive setting, the users vary their transmission power to satisfy the interference constraint. Finally, we present numerical results of our proposed algorithms where we show the trade-off between the average spectral efficiency and average feedback load of both schemes. © 2012 ICST.

Patterning of graphite nanocones for broadband solar spectrum absorption

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Yaoran Sun

2015-06-01

Full Text Available We experimentally demonstrate a broadband vis-NIR absorber consisting of 300-400 nm nanocone structures on highly oriented pyrolytic graphite. The nanocone structures are fabricated through simple nanoparticle lithography process and analyzed with three-dimensional finite-difference time-domain methods. The measured absorption reaches an average level of above 95% over almost the entire solar spectrum and agrees well with the simulation. Our simple process offers a promising material for solar-thermal devices.

Work in Television White Spaces (TVWS) and Dynamic Spectrum and a bit on Antennas

CSIR Research Space (South Africa)

Lysko, AA

2016-07-01

Full Text Available current static approach towards dynamic spectrum management. The work on smart antennas covers both physical beamswitching antenna design and development of algorithms to control the direction of the beam in a wireless mesh network. Several prototypes have...

Periodic Density Functional Theory Study of the Structure, Raman Spectrum, and Mechanical Properties of Schoepite Mineral.

Science.gov (United States)

Colmenero, Francisco; Cobos, Joaquín; Timón, Vicente

2018-04-16

The structure and Raman spectrum of schoepite mineral, [(UO 2 ) 8 O 2 (OH) 12 ]·12H 2 O, was studied by means of theoretical calculations. The computations were carried out by using density functional theory with plane waves and pseudopotentials. A norm-conserving pseudopotential specific for the U atom developed in a previous work was employed. Because it was not possible to locate H atoms directly from X-ray diffraction (XRD) data by structure refinement in previous experimental studies, all of the positions of the H atoms in the full unit cell were determined theoretically. The structural results, including the lattice parameters, bond lengths, bond angles, and powder XRD pattern, were found to be in good agreement with their experimental counterparts. However, the calculations performed using the unit cell designed by Ostanin and Zeller in 2007, involving half of the atoms of the full unit cell, led to significant errors in the computed powder XRD pattern. Furthermore, Ostanin and Zeller's unit cell contains hydronium ions, H 3 O + , which are incompatible with the experimental information. Therefore, while the use of this schoepite model may be a very useful approximation requiring a much smaller amount of computational effort, the full unit cell should be used to study this mineral accurately. The Raman spectrum was also computed by means of density functional perturbation theory and compared with the experimental spectrum. The results were also in agreement with the experimental data. A normal-mode analysis of the theoretical spectra was performed to assign the main bands of the Raman spectrum. This assignment significantly improved the current empirical assignment of the bands of the Raman spectrum of schoepite mineral. In addition, the equation of state and elastic properties of this mineral were determined. The crystal structure of schoepite was found to be stable mechanically and dynamically. Schoepite can be described as a brittle material exhibiting

Autism Spectrum Disorder and Amplified Pain

Directory of Open Access Journals (Sweden)

Ciaran Clarke

2015-01-01

Full Text Available Among the core features of ASD, altered sensitivities in all modalities have been accorded increasing importance. Heightened sensitivity to pain and unusual expressions of and reaction to pain have not hitherto been widely recognised as a presenting feature of ASD in general paediatrics. Failure to recognise ASD as a common cause of pain can lead to late diagnosis, inappropriate treatment, distress, and further disability. Two cases are presented which illustrate the late presentation of Autism Spectrum Disorder (Asperger’s Syndrome subtype with chronic unusual pain. Conclusion. Pain in autism can be atypical in its experience and expression and for this reason may go unrecognised by physicians treating chronic pain disorders.

On the Performance of In-Band Full-Duplex Cooperative Communications

KAUST Repository

Khafagy, Mohammad Galal

2016-06-01

block transmission with selective cooperation. Beyond the single-relay setting, the outage performance of different opportunistic full-duplex relay selection (FDRS) protocols is also evaluated under Rayleigh and Nakagami-m fading. It is shown that, with state-of-the-art adaptive self-interference cancellation techniques, FDRS can offer the same diversity order of its half-duplex rival while supporting a higher level of spectral efficiency. FDRS is also analyzed when adopted by a spectrum-sharing secondary system while the primary spectrum user imposes an additional interference constraint. Finally, buffer-aided hybrid half-/full-duplex cooperation is addressed. To maximize the end-to-end throughput, joint duplexing mode and link selection is studied where the system leverages the buffer and outage state information at the transmitters. All theoretic findings are corroborated with numerical simulations, with comparisons to existing protocols.

Higher-Order Spectrum in Understanding Nonlinearity in EEG Rhythms

Directory of Open Access Journals (Sweden)

Cauchy Pradhan

2012-01-01

Full Text Available The fundamental nature of the brain's electrical activities recorded as electroencephalogram (EEG remains unknown. Linear stochastic models and spectral estimates are the most common methods for the analysis of EEG because of their robustness, simplicity of interpretation, and apparent association with rhythmic behavioral patterns in nature. In this paper, we extend the use of higher-order spectrum in order to indicate the hidden characteristics of EEG signals that simply do not arise from random processes. The higher-order spectrum is an extension Fourier spectrum that uses higher moments for spectral estimates. This essentially nullifies all Gaussian random effects, therefore, can reveal non-Gaussian and nonlinear characteristics in the complex patterns of EEG time series. The paper demonstrates the distinguishing features of bispectral analysis for chaotic systems, filtered noises, and normal background EEG activity. The bispectrum analysis detects nonlinear interactions; however, it does not quantify the coupling strength. The squared bicoherence in the nonredundant region has been estimated to demonstrate nonlinear coupling. The bicoherence values are minimal for white Gaussian noises (WGNs and filtered noises. Higher bicoherence values in chaotic time series and normal background EEG activities are indicative of nonlinear coupling in these systems. The paper shows utility of bispectral methods as an analytical tool in understanding neural process underlying human EEG patterns.

The Spectrum of Learning Analytics

Directory of Open Access Journals (Sweden)

Gerd Kortemeyer

2017-06-01

Full Text Available "Learning Analytics" became a buzzword during the hype surrounding the advent of "big data" MOOCs, however, the concept has been around for over two decades. When the first online courses became available it was used as a tool to increase student success in particular courses, frequently combined with the hope of conducting educational research. In recent years, the same term started to be used on the institutional level to increase retention and decrease time-to-degree. These two applications, within particular courses on the one hand and at the institutional level on the other, are at the two extremes of the spectrum of Learning Analytics – and they frequently appear to be worlds apart. The survey describes affordances, theories and approaches in these two categories.

Spectrum and network measurements

CERN Document Server

Witte, Robert A

2014-01-01

This new edition of Spectrum and Network Measurements enables readers to understand the basic theory, relate it to measured results, and apply it when creating new designs. This comprehensive treatment of frequency domain measurements successfully consolidates all the pertinent theory into one text. It covers the theory and practice of spectrum and network measurements in electronic systems. It also provides thorough coverage of Fourier analysis, transmission lines, intermodulation distortion, signal-to-noise ratio and S-parameters.

Bose-type distribution and primary cosmic ray nucleon spectrum from sea-level muon spectrum

CERN Document Server

Bhattacharya, D P; Roychowdhury, R K

1976-01-01

The recent CERN Intersecting Storage Ring cross section data on the p +p to pi /sup +or-/+X inclusive reactions have been analysed using the Bose-type distribution of the form E(d/sup 3/ sigma )/(d/sup 3/p)=(Axs /sup 1/2/)/(exp( epsilon ( lambda )/T)-1) proposed by Hoang (1973). This formula has been used to derive the cosmic ray primary nucleon spectrum from the sea-level muon spectrum. It is found that the primary spectrum obeys the following relation: N(E/sub p/)dE/sub p /=2.06E/sub p//sup -2.64/dE/sub p/. The result has been compared with the recent experimental data and theoretical predictions given by different authors. (11 refs).

Infrascope: Full-Spectrum Phonocardiography with Automated Signal Analysis

Data.gov (United States)

National Aeronautics and Space Administration — Langley Research Center (LaRC) has developed a low frequency acoustic sensor capable of sensing frequencies below the human range of hearing primarily for...

Full Spectrum Conversion Using Traveling Pulse Wave Quantization

Science.gov (United States)

2017-03-01

range finder . While the measurement accuracy achieved is in the sub-picosecond range, the application did not require repeated measurements at very...a significantly improved Walden Figure of Merit (Figure 8). Furthermore the design builds upon the strengths of leading edge digital CMOS

[A new measurement method of time-resolved spectrum].

Science.gov (United States)

Shi, Zhi-gang; Huang, Shi-hua; Liang, Chun-jun; Lei, Quan-sheng

2007-02-01

A new method for measuring time-resolved spectrum (TRS) is brought forward. Programming with assemble language controlled the micro-control-processor (AT89C51), and a kind of peripheral circuit constituted the drive circuit, which drived the stepping motor to run the monochromator. So the light of different kinds of expected wavelength could be obtained. The optical signal was transformed to electrical signal by optical-to-electrical transform with the help of photomultiplier tube (Hamamatsu 1P28). The electrical signal of spectrum data was transmitted to the oscillograph. Connecting the two serial interfaces of RS232 between the oscillograph and computer, the electrical signal of spectrum data could be transmitted to computer for programming to draw the attenuation curve and time-resolved spectrum (TRS) of the swatch. The method for measuring time-resolved spectrum (TRS) features parallel measurement in time scale but serial measurement in wavelength scale. Time-resolved spectrum (TRS) and integrated emission spectrum of Tb3+ in swatch Tb(o-BBA)3 phen were measured using this method. Compared with the real time-resolved spectrum (TRS). It was validated to be feasible, credible and convenient. The 3D spectra of fluorescence intensity-wavelength-time, and the integrated spectrum of the swatch Tb(o-BBA)3 phen are given.

Evaluation of Spectrum Usage for GSM band in Indoor and Outdoor Scenario for Dynamic Spectrum Access

DEFF Research Database (Denmark)

Patil, Kishor P.; Barge, Snehal; Skouby, Knud Erik

2013-01-01

, and transmit power. Several measurements have shown that the current spectrum is inefficiently utilized. The inefficient utilization problem can be solved with the help of Dynamic Spectrum Access. This paper describes the GSM band measurement conducted at different locations. In this paper, we report detailed...... measurement results of GSM band including statistical as well as spectral occupancy details obtained from measurement campaign conducted in Pune, India for indoor and outdoor scenarios. The results can be further used as an input for spectrum regulator for considering Cognitive Radio (CR) operation in GSM...

A Synchronisation Method For Informed Spread-Spectrum Audiowatermarking

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Pierre-Yves Fulchiron

2003-12-01

Full Text Available Under perfect synchronisation conditions, watermarking schemes employing asymmetric spread-spectrum techniques are suitable for copy-protection of audio signals. This paper proposes to combine the use of a robust psychoacoustic projection for the extraction of a watermark feature vector along with non-linear detection functions optimised with side-information. The new proposed scheme benefits from an increased level of security through the use of asymmetric detectors. We apply this scheme to real audio signals and experimental results show an increased robustness to desynchronisation attacks such as random cropping.

CBRS Spectrum Sharing between LTE-U and WiFi: A Multiarmed Bandit Approach

Directory of Open Access Journals (Sweden)

Imtiaz Parvez

2016-01-01

Full Text Available The surge of mobile devices such as smartphone and tablets requires additional capacity. To achieve ubiquitous and high data rate Internet connectivity, effective spectrum sharing and utilization of the wireless spectrum carry critical importance. In this paper, we consider the use of unlicensed LTE (LTE-U technology in the 3.5 GHz Citizens Broadband Radio Service (CBRS band and develop a multiarmed bandit (MAB based spectrum sharing technique for a smooth coexistence with WiFi. In particular, we consider LTE-U to operate as a General Authorized Access (GAA user; hereby MAB is used to adaptively optimize the transmission duty cycle of LTE-U transmissions. Additionally, we incorporate downlink power control which yields a high energy efficiency and interference suppression. Simulation results demonstrate a significant improvement in the aggregate capacity (approximately 33% and cell-edge throughput of coexisting LTE-U and WiFi networks for different base station densities and user densities.

Smart techniques in the dynamic spectrum alocation for cognitive wireless networks

Directory of Open Access Journals (Sweden)

Camila Salgado

2016-09-01

Full Text Available Objective: The objective of this work is to study the applications of different techniques of artificial intelligence and autonomous learning in the dynamic allocation of spectrum for cognitive wireless networks, especially the distributed ones. Method: The development of this work was done through the study and analysis of some of the most relevant publications in current literature through the search in indexed international journals in ISI and Scopus. Results: the most relevant techniques of artificial intelligence and autonomous learning were determined. Also, the ones with more applicability in the allocation of spectrum for cognitive wireless networks were determined, too. . Conclusions: The implementation of a technique, or set of them, depends on the needs in signal processing, compensation in response times, sample availability, storage capacity, learning ability and robustness, among others.

Zellweger Spectrum

Science.gov (United States)

... severe defect, resulting in essentially nonfunctional peroxisomes. This phenomenon produces the range of severity of the disorders. How is the Zellweger Spectrum Diagnosed? The distinctive shape of the head and face of a child born with one of the diseases of the ...

Significance tests for the wavelet cross spectrum and wavelet linear coherence

Directory of Open Access Journals (Sweden)

Z. Ge

2008-12-01

Full Text Available This work attempts to develop significance tests for the wavelet cross spectrum and the wavelet linear coherence as a follow-up study on Ge (2007. Conventional approaches that are used by Torrence and Compo (1998 based on stationary background noise time series were used here in estimating the sampling distributions of the wavelet cross spectrum and the wavelet linear coherence. The sampling distributions are then used for establishing significance levels for these two wavelet-based quantities. In addition to these two wavelet quantities, properties of the phase angle of the wavelet cross spectrum of, or the phase difference between, two Gaussian white noise series are discussed. It is found that the tangent of the principal part of the phase angle approximately has a standard Cauchy distribution and the phase angle is uniformly distributed, which makes it impossible to establish significance levels for the phase angle. The simulated signals clearly show that, when there is no linear relation between the two analysed signals, the phase angle disperses into the entire range of [−π,π] with fairly high probabilities for values close to ±π to occur. Conversely, when linear relations are present, the phase angle of the wavelet cross spectrum settles around an associated value with considerably reduced fluctuations. When two signals are linearly coupled, their wavelet linear coherence will attain values close to one. The significance test of the wavelet linear coherence can therefore be used to complement the inspection of the phase angle of the wavelet cross spectrum. The developed significance tests are also applied to actual data sets, simultaneously recorded wind speed and wave elevation series measured from a NOAA buoy on Lake Michigan. Significance levels of the wavelet cross spectrum and the wavelet linear coherence between the winds and the waves reasonably separated meaningful peaks from those generated by randomness in the data set. As

Resource management for energy and spectrum harvesting sensor networks

CERN Document Server

Zhang, Deyu; Zhou, Haibo; Shen, Xuemin (Sherman)

2017-01-01

This SpringerBrief offers a comprehensive review and in-depth discussion of the current research on resource management. The authors explain how to best utilize harvested energy and temporally available licensed spectrum. Throughout the brief, the primary focus is energy and spectrum harvesting sensor networks (ESHNs) including energy harvesting (EH)-powered spectrum sensing and dynamic spectrum access. To efficiently collect data through the available licensed spectrum, this brief examines the joint management of energy and spectrum. An EH-powered spectrum sensing and management scheme for Heterogeneous Spectrum Harvesting Sensor Networks (HSHSNs) is presented in this brief. The scheme dynamically schedules the data sensing and spectrum access of sensors in ESHSNs to optimize the network utility, while considering the stochastic nature of EH process, PU activities and channel conditions. This brief also provides useful insights for the practical resource management scheme design for ESHSNs and motivates a ne...

Full-range k-domain linearization in spectral-domain optical coherence tomography.

Science.gov (United States)

Jeon, Mansik; Kim, Jeehyun; Jung, Unsang; Lee, Changho; Jung, Woonggyu; Boppart, Stephen A

2011-03-10

A full-bandwidth k-domain linearization method for spectral-domain optical coherence tomography (SD-OCT) is demonstrated. The method uses information of the wavenumber-pixel-position provided by a translating-slit-based wavelength filter. For calibration purposes, the filter is placed either after a broadband source or at the end of the sample path, and the filtered spectrum with a narrowed line width (∼0.5 nm) is incident on a line-scan camera in the detection path. The wavelength-swept spectra are co-registered with the pixel positions according to their central wavelengths, which can be automatically measured with an optical spectrum analyzer. For imaging, the method does not require a filter or a software recalibration algorithm; it simply resamples the OCT signal from the detector array without employing rescaling or interpolation methods. The accuracy of k-linearization is maximized by increasing the k-linearization order, which is known to be a crucial parameter for maintaining a narrow point-spread function (PSF) width at increasing depths. The broadening effect is studied by changing the k-linearization order by undersampling to search for the optimal value. The system provides more position information, surpassing the optimum without compromising the imaging speed. The proposed full-range k-domain linearization method can be applied to SD-OCT systems to simplify their hardware/software, increase their speed, and improve the axial image resolution. The experimentally measured width of PSF in air has an FWHM of 8 μm at the edge of the axial measurement range. At an imaging depth of 2.5 mm, the sensitivity of the full-range calibration case drops less than 10 dB compared with the uncompensated case.

Admission Control and Interference Management in Dynamic Spectrum Access Networks

Directory of Open Access Journals (Sweden)

Jorge Martinez-Bauset

2010-01-01

Full Text Available We study two important aspects to make dynamic spectrum access work in practice: the admission policy of secondary users (SUs to achieve a certain degree of quality of service and the management of the interference caused by SUs to primary users (PUs. In order to limit the forced termination probability of SUs, we evaluate the Fractional Guard Channel reservation scheme to give priority to spectrum handovers over new arrivals. We show that, contrary to what has been proposed, the throughput of SUs cannot be maximized by configuring the reservation parameter. We also study the interference caused by SUs to PUs. We propose and evaluate different mechanisms to reduce the interference, which are based on simple spectrum access algorithms for both PUs and SUs and channel repacking algorithms for SUs. Numerical results show that the reduction can be of one order of magnitude or more with respect to the random access case. Finally, we propose an adaptive admission control scheme that is able to limit simultaneously the forced termination probability of SUs and what we define as the probability of interference. Our scheme does not require any configuration parameters beyond the probability objectives. Besides, it is simple to implement and it can operate with any arrival process and distribution of the session duration.

Adjustment of the 235U Fission Spectrum

International Nuclear Information System (INIS)

GRIFFIN, PATRICK J.; WILLIAMS, J.G.

1999-01-01

The latest nuclear data are used to examine the sensitivity of the least squares adjustment of the 235 U fission spectrum to the measured reaction rates, dosimetry cross sections, and prior spectrum covariance matrix. All of these parameters were found to be very important in the spectrum adjustment. The most significant deficiency in the nuclear data is the absence of a good prior covariance matrix. Covariance matrices generated from analytic models of the fission spectra have been used in the past. This analysis reveals some unusual features in the covariance matrix produced with this approach. Specific needs are identified for improved nuclear data to better determine the 235 U spectrum. An improved 235 U covariance matrix and adjusted spectrum are recommended for use in radiation transport sensitivity analyses

Analysis of the spectrum distribution of oscillation amplitudes of the concrete mix at shock vibration molding

Directory of Open Access Journals (Sweden)

Sharapov Rashid

2017-01-01

Full Text Available In the production of concrete structures widespread shaking tables of various designs. The effectiveness of vibroforming concrete items largely depends on the choice of rational modes of vibroeffect to the compacting mixture. The article discusses the propagation of a wave packet in the concrete mixture under shock and vibration molding. Studies have shown that the spectrum of a wave packet contains a large number of harmonics. The main parameter influencing the amplitude-frequency spectrum is the stiffness of elastic gaskets between mold and forming machine vibrating table. By varying the stiffness of the elastic gaskets can widely change the spectrum of the oscillations propagating in the concrete mix. Thus, it is possible to adjust the intensity of the process of vibroforming.

Auction based spectrum management of cognitive radio networks

DEFF Research Database (Denmark)

Chang, H. B.; Chen, K.-C.; Prasad, Ramjee

2009-01-01

(PS-MSs), and we therefore construct a cognitive radio network (CRN) consisting of a PRN with multiple CR-MSs. We propose a spectrum management policy framework such that CR-MSs can compete in utilization of the PRN spectrum bands available to opportunistic transmission of CR-MSs by Vickrey auction...... to the PRN, the overall spectrum utilization, the profit of the service provider, the spectrum access opportunity of the CR-MSs are increased to achieve cowin situation for every party in cognitive radio networks.......Cognitive radio (CR) technology is considered as an effective solution to enhance overall spectrum efficiency, especially primary radio network (PRN) typically having relatively low spectrum utilization. However, to realize CR concept, it is essential to provide enough incentives to PRN and extra...

Outdoor measurements of a photovoltaic system using diffractive spectrum-splitting and concentration

Directory of Open Access Journals (Sweden)

N. Mohammad

2016-09-01

Full Text Available In a single-bandgap absorber, photons having energy less than the bandgap are not absorbed, while those having energy larger than the bandgap lose the excess energy via thermalization. We present outdoor measurements of a photovoltaic system that overcomes these losses via spectrum splitting and concentration using a planar diffractive optic. The system was comprised of the diffractive optic coupled with GaInP and CIGS solar cells. The optic provides a geometric concentration of 3X for each solar cell. It is easily fabricated by single-step grayscale lithography and it is ultra-thin with a maximum thickness of only 2.5μm. Electrical measurements under direct sunlight demonstrated an increase of ∼25% in total output power compared to the reference case without spectrum splitting and concentration. Since different bandgaps are in the same plane, the proposed photovoltaic system successfully circumvents the lattice-matching and current-matching issues in conventional tandem multi-junction solar cells. This system is also tolerant to solar spectrum variation and fill-factor degradation of constitutive solar cells.

Joint opportunistic beam and spectrum selection schemes for spectrum sharing systems with limited feedback

KAUST Repository

Sayed, Mostafa M.

2014-11-01

Spectrum sharing systems have been introduced to alleviate the problem of spectrum scarcity by allowing an unlicensed secondary user (SU) to share the spectrum with a licensed primary user (PU) under acceptable interference levels to the primary receiver (PU-Rx). In this paper, we consider a secondary link composed of a secondary transmitter (SU-Tx) equipped with multiple antennas and a single-antenna secondary receiver (SU-Rx). The secondary link is allowed to share the spectrum with a primary network composed of multiple PUs communicating over distinct frequency spectra with a primary base station. We develop a transmission scheme where the SU-Tx initially broadcasts a set of random beams over all the available primary spectra for which the PU-Rx sends back the index of the spectrum with the minimum interference level, as well as information that describes the interference value, for each beam. Based on the feedback information on the PU-Rx, the SU-Tx adapts the transmitted beams and then resends the new beams over the best primary spectrum for each beam to the SU-Rx. The SU-Rx selects the beam that maximizes the received signal-to-interference-plus-noise ratio (SINR) to be used in transmission over the next frame. We consider three cases for the level of feedback information describing the interference level. In the first case, the interference level is described by both its magnitude and phase; in the second case, only the magnitude is considered; and in the third case, we focus on a q-bit description of its magnitude. In the latter case, we propose a technique to find the optimal quantizer thresholds in a mean-square-error sense. We also develop a statistical analysis for the SINR statistics and the capacity and bit error rate of the secondary link and present numerical results that study the impact of the different system parameters.

Spectrum optimization-based chaotification using time-delay feedback control

International Nuclear Information System (INIS)

Zhou Jiaxi; Xu Daolin; Zhang Jing; Liu Chunrong

2012-01-01

Highlights: ► A time-delay feedback controller is designed for chaotification. ► A spectrum optimization method is proposed to determine chaotification parameters. ► Numerical examples verify the spectrum optimization- based chaotification method. ► Engineering application in line spectrum reconfiguration is demonstrated. - Abstract: In this paper, a spectrum optimization method is developed for chaotification in conjunction with an application in line spectrum reconfiguration. A key performance index (the objective function) based on Fourier spectrum is specially devised with the idea of suppressing spectrum spikes and broadening frequency band. Minimization of the index empowered by a genetic algorithm enables to locate favorable parameters of the time-delay feedback controller, by which a line spectrum of harmonic vibration can be transformed into a broad-band continuous spectrum of chaotic motion. Numerical simulations are carried out to verify the feasibility of the method and to demonstrate its effectiveness of chaotifying a 2-DOFs linear mechanical system.

A general approach for haplotype phasing across the full spectrum of relatedness.

Directory of Open Access Journals (Sweden)

Jared O'Connell

2014-04-01

Full Text Available Many existing cohorts contain a range of relatedness between genotyped individuals, either by design or by chance. Haplotype estimation in such cohorts is a central step in many downstream analyses. Using genotypes from six cohorts from isolated populations and two cohorts from non-isolated populations, we have investigated the performance of different phasing methods designed for nominally 'unrelated' individuals. We find that SHAPEIT2 produces much lower switch error rates in all cohorts compared to other methods, including those designed specifically for isolated populations. In particular, when large amounts of IBD sharing is present, SHAPEIT2 infers close to perfect haplotypes. Based on these results we have developed a general strategy for phasing cohorts with any level of implicit or explicit relatedness between individuals. First SHAPEIT2 is run ignoring all explicit family information. We then apply a novel HMM method (duoHMM to combine the SHAPEIT2 haplotypes with any family information to infer the inheritance pattern of each meiosis at all sites across each chromosome. This allows the correction of switch errors, detection of recombination events and genotyping errors. We show that the method detects numbers of recombination events that align very well with expectations based on genetic maps, and that it infers far fewer spurious recombination events than Merlin. The method can also detect genotyping errors and infer recombination events in otherwise uninformative families, such as trios and duos. The detected recombination events can be used in association scans for recombination phenotypes. The method provides a simple and unified approach to haplotype estimation, that will be of interest to researchers in the fields of human, animal and plant genetics.

EFFICIENT SPECTRUM UTILIZATION IN COGNITIVE RADIO THROUGH REINFORCEMENT LEARNING

Directory of Open Access Journals (Sweden)

Dhananjay Kumar

2013-09-01

Full Text Available Machine learning schemes can be employed in cognitive radio systems to intelligently locate the spectrum holes with some knowledge about the operating environment. In this paper, we formulate a variation of Actor Critic Learning algorithm known as Continuous Actor Critic Learning Automaton (CACLA and compare this scheme with Actor Critic Learning scheme and existing Q–learning scheme. Simulation results show that our CACLA scheme has lesser execution time and achieves higher throughput compared to other two schemes.

Application of a Channel Estimation Algorithm to Spectrum Sensing in a Cognitive Radio Context

Directory of Open Access Journals (Sweden)

Vincent Savaux

2014-01-01

Full Text Available This paper deals with spectrum sensing in an orthogonal frequency division multiplexing (OFDM context, allowing an opportunistic user to detect a vacant spectrum resource in a licensed band. The proposed method is based on an iterative algorithm used for the joint estimation of noise variance and frequency selective channel. It can be seen as a second-order detector, since it is performed by means of the minimum mean square error criterion. The main advantage of the proposed algorithm is its capability to perform spectrum sensing, noise variance estimation, and channel estimation in the presence of a signal. Furthermore, the sensing duration is limited to only one OFDM symbol. We theoretically show the convergence of the algorithm, and we derive its analytical detection and false alarm probabilities. Furthermore, we show that the detector is very efficient, even for low SNR values, and is robust against a channel uncertainty.

Noise spectrum of quantum transport through double quantum dots: Renormalization and non-Markovian effects

Directory of Open Access Journals (Sweden)

Pengqin Shi

2016-09-01

Full Text Available Based on the time-nonlocal particle number-resolved master equation, we investigate the sequential electron transport through the interacting double quantum dots. Our calculations show that there exists the effect of energy renormalization in the dispersion of the bath interaction spectrum and it is sensitive to the the bandwidth of the bath. This effect would strongly affect the stationary current and its zero-frequency shot noise for weak inter-dot coherent coupling strength, but for strong inter-dot coupling regime, it is negligible due to the strong intrinsic Rabi coherent dynamics. Moreover, the possible observable effects of the energy renormalization in the noise spectrum are also investigated through the Rabi coherence signal. Finally, the non-Markovian effect is manifested in the finite-frequency noise spectrum with the appearance of quasisteps, and the magnitude of these quasisteps are modified by the dispersion function.

Analyzing Chaos Systems and Fine Spectrum Sensing Using Detrended Fluctuation Analysis Algorithm

Directory of Open Access Journals (Sweden)

Javier S. González-Salas

2016-01-01

Full Text Available A numerical study that uses detrended fluctuation analysis (DFA algorithm of time series obtained from linear and nonlinear dynamical systems is presented. The DFA algorithm behavior toward periodic and chaotic signals is investigated and the effect of the time scale under analysis is discussed. The displayed results prove that the DFA algorithm response is invariant (stable performance to initial condition and chaotic system parameters. An initial idea of DFA algorithm implementation for fine spectrum sensing (SS is proposed under two-stage spectrum sensor approach with test statistics based on the scaling exponent value. The outcomes demonstrate a promising new SS technique that can alleviate several imperfections such as noise power uncertainty and spatial correlation between the adjacent antenna array elements.

Fingerprint extraction from interference destruction terahertz spectrum.

Science.gov (United States)

Xiong, Wei; Shen, Jingling

2010-10-11

In this paper, periodic peaks in a terahertz absorption spectrum are confirmed to be induced from interference effects. Theoretically, we explained the periodic peaks and calculated the locations of them. Accordingly, a technique was suggested, with which the interference peaks in a terahertz spectrum can be eliminated and therefore a real terahertz absorption spectrum can be obtained. Experimentally, a sample, Methamphetamine, was investigated and its terahertz fingerprint was successfully extracted from its interference destruction spectrum. This technique is useful in getting samples' terahertz fingerprint spectra, and furthermore provides a fast nondestructive testing method using a large size terahertz beam to identify materials.

Genetics Home Reference: autism spectrum disorder

Science.gov (United States)

... Share: Email Facebook Twitter Home Health Conditions ASD Autism spectrum disorder Printable PDF Open All Close All Enable Javascript to view the expand/collapse boxes. Description Autism spectrum disorder ( ASD ) is a condition that appears very early ...

Systematic review of the prevalence of bipolar disorder and bipolar spectrum disorders in population-based studies

Directory of Open Access Journals (Sweden)

José Caetano Dell'Aglio Jr.

2013-01-01

Full Text Available This paper describes the findings of a systematic literature review aimed at providing an overview of the lifetime prevalence of bipolar disorder and bipolar spectrum disorders in population-based studies. Databases MEDLINE, ProQuest, Psychnet, and Web of Science were browsed for papers published in English between 1999 and May 2012 using the following search string: bipolar disorders OR bipolar spectrum disorders AND prevalence OR cross-sectional OR epidemiology AND population-based OR non-clinical OR community based. The search yielded a total of 434 papers, but only those published in peer-reviewed journals and with samples aged ≥ 18 years were included, resulting in a final sample of 18 papers. Results revealed rather heterogeneous findings concerning the prevalence of bipolar disorders and bipolar spectrum disorders. Lifetime prevalence of bipolar disorder ranged from 0.1 to 7.5%, whereas lifetime prevalence of bipolar spectrum disorders ranged from 2.4 to 15.1%. Differences in the rates of bipolar disorder and bipolar spectrum disorders may be related to the consideration of subthreshold criteria upon diagnosis. Differences in the prevalence of different subtypes of the disorder are discussed in light of diagnostic criteria and instruments applied.

Consideration of vertical seismic response spectrum in nuclear safety review

International Nuclear Information System (INIS)

Sun Zaozhan; Huang Bingchen

2011-01-01

The basic requirements for civil nuclear installation are introduced in the article. Starting from the basic concept of seismic response spectrum, the authors analyze the site seismic response spectrum and the design seismic response spectrum that desire much consideration. By distinguishing the absolute seismic response spectrum and relative seismic response spectrum, the authors analyze the difference and relationship between the vertical seismic response spectrum and horizontal seismic response spectrum. The authors also bring forward some suggestions for determining the site vertical seismic response spectrum by considering the fact in our country. (authors)

Anesthetic management of a child with autistic spectrum disorder and homocysteinemia

Directory of Open Access Journals (Sweden)

Deepak Choudhary

2016-01-01

Full Text Available Autistic spectrum disorder (ASD is a developmental disability of the central nervous system with rapid worsening. A subset of patients also has mitochondrial dysfunction leading to increased sensitivity to various anesthetic agents. Rarely, gene mutation in these patients results in homocysteinemia which causes higher incidences of thromboembolism, hypoglycemia, and seizures. Anesthetic management of ASD with homocysteinemia and refractory seizures has not been previously reported.

Autism Spectrum Disorder and Mitochondrial Disease

Science.gov (United States)

... Search Form Controls Cancel Submit Search the CDC Autism Spectrum Disorder (ASD) Note: Javascript is disabled or is not ... with a mitochondrial disease: may also have an autism spectrum disorder, may have some of the symptoms/signs of ...

Autism Spectrum Disorder (ASD): Related Topics

Science.gov (United States)

... Facebook Tweet Share Compartir Q: Do vaccines cause autism spectrum disorder (ASD)? A: Many studies that have looked at whether there is a relationship between vaccines and autism spectrum disorder (ASD). To date, the studies continue to show ...

Broad spectrum antiangiogenic treatment for ocular neovascular diseases.

Directory of Open Access Journals (Sweden)

Ofra Benny

2010-09-01

Full Text Available Pathological neovascularization is a hallmark of late stage neovascular (wet age-related macular degeneration (AMD and the leading cause of blindness in people over the age of 50 in the western world. The treatments focus on suppression of choroidal neovascularization (CNV, while current approved therapies are limited to inhibiting vascular endothelial growth factor (VEGF exclusively. However, this treatment does not address the underlying cause of AMD, and the loss of VEGF's neuroprotective can be a potential side effect. Therapy which targets the key processes in AMD, the pathological neovascularization, vessel leakage and inflammation could bring a major shift in the approach to disease treatment and prevention. In this study we have demonstrated the efficacy of such broad spectrum antiangiogenic therapy on mouse model of AMD.Lodamin, a polymeric formulation of TNP-470, is a potent broad-spectrum antiangiogenic drug. Lodamin significantly reduced key processes involved in AMD progression as demonstrated in mice and rats. Its suppressive effects on angiogenesis, vascular leakage and inflammation were studied in a wide array of assays including; a Matrigel, delayed-type hypersensitivity (DTH, Miles assay, laser-induced CNV and corneal micropocket assay. Lodamin significantly suppressed the secretion of various pro-inflammatory cytokines in the CNV lesion including monocyte chemotactic protein-1 (MCP-1/Ccl2. Importantly, Lodamin was found to regress established CNV lesions, unlike soluble fms-like tyrosine kinase-1 (sFlk-1. The drug was found to be safe in mice and have little toxicity as demonstrated by electroretinography (ERG assessing retinal and by histology.Lodamin, a polymer formulation of TNP-470, was identified as a first in its class, broad-spectrum antiangiogenic drug that can be administered orally or locally to treat corneal and retinal neovascularization. Several unique properties make Lodamin especially beneficial for ophthalmic

Clinical Spectrum of Stiff Person Syndrome: A Review of Recent Reports

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Harini Sarva

2016-03-01

Full Text Available Background: “Classic” stiff person syndrome (SPS features stiffness, anti-glutamic acid decarboxylase (anti-GAD antibodies, and other findings. Anti-GAD antibodies are also detected in some neurological syndromes (such as ataxia in which stiffness is inconsistently present. Patients with otherwise “classic” SPS may either lack anti-GAD antibodies or be seropositive for others. Hence, SPS cases appear to fall within a clinical spectrum that includes conditions such as progressive encephalomyelitis with rigidity and myoclonus (PERM, which exhibits brainstem and autonomic features. We have compiled herein SPS-spectrum cases reported since 2010, and have segregated them on the basis of likely disease mechanism (autoimmune, paraneoplastic, or cryptogenic for analysis. Methods: The phrases “stiff person syndrome”, “PERM”, “anti-GAD antibody syndrome”, and “glycine receptor antibody neurological disorders” were searched for in PubMed in January 2015. The results were narrowed to 72 citations after excluding non-English and duplicate reports. Clinical descriptions, laboratory data, management, and outcomes were categorized, tabulated, and analyzed. Results: Sixty-nine autoimmune, 19 paraneoplastic, and 13 cryptogenic SPS-spectrum cases were identified. SPS was the predominant diagnosis among the groups. Roughly two-thirds of autoimmune and paraneoplastic cases were female. Anti-GAD antibodies were most frequently identified, followed by anti-amphiphysin among paraneoplastic cases and by anti-glycine receptor antibodies among autoimmune cases. Benzodiazepines were the most commonly used medications. Prognosis seemed best for cryptogenic cases; malignancy worsened that of paraneoplastic cases. Discussion: Grouping SPS-spectrum cases by pathophysiology provided insights into work-up, treatment, and prognosis. Ample phenotypic and serologic variations are present within the categories. Ruling out malignancy and autoimmunity is

The high-resolution extraterrestrial solar spectrum (QASUMEFTS determined from ground-based solar irradiance measurements

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J. Gröbner

2017-09-01

Full Text Available A high-resolution extraterrestrial solar spectrum has been determined from ground-based measurements of direct solar spectral irradiance (SSI over the wavelength range from 300 to 500 nm using the Langley-plot technique. The measurements were obtained at the Izaña Atmospheric Research Centre from the Agencia Estatal de Meteorología, Tenerife, Spain, during the period 12 to 24 September 2016. This solar spectrum (QASUMEFTS was combined from medium-resolution (bandpass of 0.86 nm measurements of the QASUME (Quality Assurance of Spectral Ultraviolet Measurements in Europe spectroradiometer in the wavelength range from 300 to 500 nm and high-resolution measurements (0.025 nm from a Fourier transform spectroradiometer (FTS over the wavelength range from 305 to 380 nm. The Kitt Peak solar flux atlas was used to extend this high-resolution solar spectrum to 500 nm. The expanded uncertainties of this solar spectrum are 2 % between 310 and 500 nm and 4 % at 300 nm. The comparison of this solar spectrum with solar spectra measured in space (top of the atmosphere gave very good agreements in some cases, while in some other cases discrepancies of up to 5 % were observed. The QASUMEFTS solar spectrum represents a benchmark dataset with uncertainties lower than anything previously published. The metrological traceability of the measurements to the International System of Units (SI is assured by an unbroken chain of calibrations leading to the primary spectral irradiance standard of the Physikalisch-Technische Bundesanstalt in Germany.

Cooperation Techniques between LTE in Unlicensed Spectrum and Wi-Fi towards Fair Spectral Efficiency

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Vasilis Maglogiannis

2017-08-01

Full Text Available On the road towards 5G, a proliferation of Heterogeneous Networks (HetNets is expected. Sensor networks are of great importance in this new wireless era, as they allow interaction with the environment. Additionally, the establishment of the Internet of Things (IoT has incredibly increased the number of interconnected devices and consequently the already massive wirelessly transmitted traffic. The exponential growth of wireless traffic is pushing the wireless community to investigate solutions that maximally exploit the available spectrum. Recently, 3rd Generation Partnership Project (3GPP announced standards that permit the operation of Long Term Evolution (LTE in the unlicensed spectrum in addition to the exclusive use of the licensed spectrum owned by a mobile operator. Alternatively, leading wireless technology developers examine standalone LTE operation in the unlicensed spectrum without any involvement of a mobile operator. In this article, we present a classification of different techniques that can be applied on co-located LTE and Wi-Fi networks. Up to today, Wi-Fi is the most widely-used wireless technology in the unlicensed spectrum. A review of the current state of the art further reveals the lack of cooperation schemes among co-located networks that can lead to more optimal usage of the available spectrum. This article fills this gap in the literature by conceptually describing different classes of cooperation between LTE and Wi-Fi. For each class, we provide a detailed presentation of possible cooperation techniques that can provide spectral efficiency in a fair manner.

A Method to Reconstruct the Solar-Induced Canopy Fluorescence Spectrum from Hyperspectral Measurements

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Feng Zhao

2014-10-01

Full Text Available A method for canopy Fluorescence Spectrum Reconstruction (FSR is proposed in this study, which can be used to retrieve the solar-induced canopy fluorescence spectrum over the whole chlorophyll fluorescence emission region from 640–850 nm. Firstly, the radiance of the solar-induced chlorophyll fluorescence (Fs at five absorption lines of the solar spectrum was retrieved by a Spectral Fitting Method (SFM. The Singular Vector Decomposition (SVD technique was then used to extract three basis spectra from a training dataset simulated by the model SCOPE (Soil Canopy Observation, Photochemistry and Energy fluxes. Finally, these basis spectra were linearly combined to reconstruct the Fs spectrum, and the coefficients of them were determined by Weighted Linear Least Squares (WLLS fitting with the five retrieved Fs values. Results for simulated datasets indicate that the FSR method could accurately reconstruct the Fs spectra from hyperspectral measurements acquired by instruments of high Spectral Resolution (SR and Signal to Noise Ratio (SNR. The FSR method was also applied to an experimental dataset acquired in a diurnal experiment. The diurnal change of the reconstructed Fs spectra shows that the Fs radiance around noon was higher than that in the morning and afternoon, which is consistent with former studies. Finally, the potential and limitations of this method are discussed.

Full-color, large area, transmissive holograms enabled by multi-level diffractive optics.

Science.gov (United States)

Mohammad, Nabil; Meem, Monjurul; Wan, Xiaowen; Menon, Rajesh

2017-07-19

We show that multi-level diffractive microstructures can enable broadband, on-axis transmissive holograms that can project complex full-color images, which are invariant to viewing angle. Compared to alternatives like metaholograms, diffractive holograms utilize much larger minimum features (>10 µm), much smaller aspect ratios (30 mm ×30 mm). We designed, fabricated and characterized holograms that encode various full-color images. Our devices demonstrate absolute transmission efficiencies of >86% across the visible spectrum from 405 nm to 633 nm (peak value of about 92%), and excellent color fidelity. Furthermore, these devices do not exhibit polarization dependence. Finally, we emphasize that our devices exhibit negligible absorption and are phase-only holograms with high diffraction efficiency.

Adult Autism Subthreshold Spectrum (AdAS Spectrum) in parents of pediatric patients with epilepsy: Correlations with post-traumatic stress symptoms.

Science.gov (United States)

Dell'Osso, L; Corsi, M; Gesi, C; Bertelloni, C A; Massimetti, G; Peroni, D; Bonuccelli, A; Orsini, A; Carmassi, C

2018-05-01

Increasing literature has shown the usefulness of a dimensional approach to mental disorders, particularly when exploring subjects exposed to traumatic experiences such as a severe illness in one's child. Recent evidence suggests an increased vulnerability in subjects with autism spectrum symptoms to develop post-traumatic stress symptoms. The aim of the present study was to evaluate the presence of adult autism subthreshold spectrum in a sample of parents of children with epilepsy and its impact on post-traumatic stress spectrum symptoms in the same study sample. Results revealed noteworthy correlations between post-traumatic stress symptoms and adult autism subthreshold spectrum (AdAS Spectrum) only in the subgroup of the fathers. In particular, were evidenced correlations between AdAS Spectrum domain of rumination and narrow interests and some TALS-SR nuclear domains: reaction to traumatic events, reexperiencing and arousal. These findings corroborate the hypothesis that subthreshold autistic features may influence the possible psychopathological reaction to trauma. Copyright © 2018 Elsevier Inc. All rights reserved.

Activation method for measurement of neutron spectrum parameters

International Nuclear Information System (INIS)

Efimov, B.V.; Demidov, A.M.; Ionov, V.S.; Konjaev, S.I.; Marin, S.V.; Bryzgalov, V.I.

2007-01-01

Experimental researches of spectrum parameters of neutrons at nuclear installations RRC KI are submitted. The installations have different designs of the cores, reflector, parameters and types of fuel elements. Measurements were carried out with use of the technique developed in RRC KI for irradiation resonance detectors UKD. The arrangement of detectors in the cores ensured possibility of measurement of neutron spectra with distinguished values of parameters. The spectrum parameters which are introduced by parametrical representation of a neutrons spectrum in the form corresponding to formalism Westcott. On experimental data were determinate absolute values of density neutron flux (DNF) in thermal and epithermal area of a spectrum (F t , f epi ), empirical dependence of temperature of neutron gas (Tn) on parameter of a rigidity of a spectrum (z), density neutron flux in transitional energy area of the spectrum. Dependences of spectral indexes of nuclides (UDy/UX), included in UKD, from a rigidity z and-or temperatures of neutron gas Tn are obtained.B Tools of mathematical processing of results are used for activation data and estimation of parameters of a spectrum (F t , f epi , z, Tn, UDy/UX). In the paper are presented some results of researches of neutron spectrum parameters of the nuclear installations (Authors)

Spectrum pooling in MnWave Networks

DEFF Research Database (Denmark)

Boccardi, Federico; Shokri-Ghadikolaei, Hossein; Fodor, Gabor

2016-01-01

Motivated by the specific characteristics of mmWave technologies, we discuss the possibility of an authorization regime that allows spectrum sharing between multiple operators, also referred to as spectrum pooling. In particular, considering user rate as the performance measure, we assess...

Project Spectrum: An Innovative Assessment Alternative.

Science.gov (United States)

Krechevsky, Mara

1991-01-01

Project Spectrum attempts to reconceptualize the traditional linguistic and logical/mathematical bases of intelligence. Spectrum blurs the line between curriculum and assessment, embeds assessment in meaningful, real-world activities, uses "intelligence-fair" measures, emphasizes children's strengths, and recognizes the stylistic…

Clinical Genetic Aspects of ASD Spectrum Disorders

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G. Bradley Schaefer

2016-01-01

Full Text Available Early presumptions opined that autism spectrum disorder (ASD was related to the rearing of these children by emotionally-distant mothers. Advances in the 1960s and 1970s clearly demonstrated the biologic basis of autism with a high heritability. Recent advances have demonstrated that specific etiologic factors in autism spectrum disorders can be identified in 30%–40% of cases. Based on early reports newer, emerging genomic technologies are likely to increase this diagnostic yield to over 50%. To date these investigations have focused on etiologic factors that are largely mono-factorial. The currently undiagnosed causes of ASDs will likely be found to have causes that are more complex. Epigenetic, multiple interacting loci, and four dimensional causes (with timing as a variable are likely to be associated with the currently unidentifiable cases. Today, the “Why” is more important than ever. Understanding the causes of ASDs help inform families of important issues such as recurrence risk, prognosis, natural history, and predicting associated co-morbid medical conditions. In the current era of emerging efforts in “personalized medicine”, identifying an etiology will be critical in identifying endo-phenotypic groups and individual variations that will allow for tailored treatment for persons with ASD.

Prevalence of Schizophrenia Spectrum Disorders in Average-IQ Adults with Autism Spectrum Disorders: A Meta-Analysis

Science.gov (United States)

Lugo Marín, Jorge; Rodríguez-Franco, Montserrat Alviani; Mahtani Chugani, Vinita; Magán Maganto, María; Díez Villoria, Emiliano; Canal Bedia, Ricardo

2018-01-01

Since their separation as independent diagnostics, autism spectrum disorders (ASD) and schizophrenia spectrum disorders (SSD) have been conceptualized as mutually exclusive disorders. Similarities between both disorders can lead to misdiagnosis, especially when it comes to average-IQ adults who were not identified during childhood. The aim of this…

New fission-neutron-spectrum representation for ENDF

International Nuclear Information System (INIS)

Madland, D.G.

1982-04-01

A new representation of the prompt fission neutron spectrum is proposed for use in the Evaluated Nuclear Data File (ENDF). The proposal is made because a new theory exists by which the spectrum can be accurately predicted as a function of the fissioning nucleus and its excitation energy. Thus, prompt fission neutron spectra can be calculated for cases where no measurements exist or where measurements are not possible. The mathematical formalism necessary for application of the new theory within ENDF is presented and discussed for neutron-induced fission and spontaneous fission. In the case of neutron-induced fission, expressions are given for the first-chance, second-chance, third-chance, and fourth-chance fission components of the spectrum together with that for the total spectrum. An ENDF format is proposed for the new fission spectrum representation, and an example of the use of the format is given

Full-Duplex Relay Selection in Cognitive Underlay Networks

KAUST Repository

Khafagy, Mohammad Galal

2017-09-30

In this work, we analyze the performance of full-duplex relay selection (FDRS) in spectrum-sharing networks. Contrary to half-duplex relaying, full-duplex relaying (FDR) enables simultaneous listening/forwarding at the secondary relay(s), thereby allowing for a higher spectral efficiency. However, since the source and relay simultaneously transmit in FDR, their superimposed signal at the primary receiver should now satisfy the existing interference constraint, which can considerably limit the secondary network throughput. In this regard, relay selection can offer an adequate solution to boost the secondary throughput while satisfying the imposed interference limit. We first analyze the performance of opportunistic FDRS with residual self-interference (RSI) by deriving the exact cumulative distribution function of its end-to-end signal-to-interference-plus-noise ratio under Nakagami-m fading. We also evaluate the offered diversity gain of relay selection for different full-duplex cooperation schemes in the presence/absence of a direct source-destination link. When the adopted RSI link gain model is sublinear in the relay power, which agrees with recent research findings, we show that remarkable diversity gain can be recovered even in the presence of an interfering direct link. Second, we evaluate the end-to-end performance of FDRS with interference constraints due to the presence of a primary receiver. Finally, the presented exact theoretical findings are verified by numerical simulations.

The frequency spectrum crisis - Issues and answers

Science.gov (United States)

Armes, G. L.

The frequency spectrum represents a unique resource which can be overtaxed. In the present investigation, it is attempted to evalute the demand for satellite and microwave services. Dimensions of increased demand are discussed, taking into account developments related to the introduction of the personal computer, the activities of the computer and communications industries in preparation for the office of the future, and electronic publishing. Attention is given to common carrier spectrum congestion, common carrier microwave, satellite communications, teleports, international implications, satellite frequency bands, satellite spectrum implications, alternatives regarding the utilization of microwave frequency bands, U.S. Government spectrum utilization, and the impact at C-band.

Trends in broad-spectrum antibiotic prescribing for children with acute otitis media in the United States, 1998–2004

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Gambler Angela S

2009-06-01

Full Text Available Abstract Background Overuse of broad-spectrum antibiotics is associated with antibiotic resistance. Acute otitis media (AOM is responsible for a large proportion of antibiotics prescribed for US children. Rates of broad-spectrum antibiotic prescribing for AOM are unknown. Methods Analysis of the National Ambulatory Medical Care Survey and National Hospital Ambulatory Medical Care Survey, 1998 to 2004 (N = 6,878. Setting is office-based physicians, hospital outpatient departments, and emergency departments. Patients are children aged 12 years and younger prescribed antibiotics for acute otitis media. Main outcome measure is percentage of broad-spectrum antibiotics, defined as amoxicillin/clavulanate, macrolides, cephalosporins and quinolones. Results Broad-spectrum prescribing for acute otitis media increased from 34% of visits in 1998 to 45% of visits in 2004 (P Conclusion Prescribing of broad-spectrum antibiotics for acute otitis media has steadily increased from 1998 to 2004. Associations with non-clinical factors suggest potential for improvement in prescribing practice.

Teacher Training for Implementation of Teaching Strategies for Students with Autism Spectrum Disorders

Science.gov (United States)

Morrier, Michael J.; Hess, Kristen L.; Heflin, L. Juane

2011-01-01

Training received by teachers of students with autism spectrum disorders (ASD) in one southern state was investigated. Teachers (n = 90) reported training received via an online version of the Autism Treatment Survey. The most common type of training reported was attendance at a full- or half-day workshop; fewer than 15% reported receiving…

The Neutron Spectrum in a Uranium Tube

International Nuclear Information System (INIS)

Johansson, E.; Jonsson, E.; Lindberg, M.; Mednis, J.

1963-10-01

A series of experimental and theoretical investigations on neutron spectra in lattice cells has been started at the reactor R1. This report gives the results from the first one of these cells - one with a tube of natural -uranium surrounded by heavy water. In the measurements the cell was placed in the central, vertical channel of the reactor. The neutron spectrum from a lead scatterer in the uranium tube - outer diameter 49.2 mm, inner diameter 28.3 mm - was measured with a fast chopper in the energy region 0.01 to 100 eV. Subsidiary measurements indicated that the spectrum in the beam from the lead piece corresponds to the spectrum of the angular flux integrated over all angles. This correspondence is important for the interpretation of the experimental data. The thermal part of the spectrum was found to deviate significantly from a Maxwellian. However, the deviation is not very large, and one could use a Maxwellian, at least to give a rough idea of the hardness of the spectrum. For the present tube the temperature of this Maxwellian was estimated as 90 to 100 deg C above the moderator temperature (33 deg C). In the joining region the rise of the spectrum towards the thermal part is slower than for the cell boundary spectrum, measured earlier. In the epithermal region the limited resolution of the chopper has affected the measurements at the energies of the uranium resonances. However, the shape of the spectrum on the flanks of the first resonance in 238 U (6.68 eV) has been obtained accurately. In the theoretical treatment the THERMOS code with a free gas scattering model has been used. The energy region was 3.06 - 0.00025 eV. The agreement with the measurements is good for the thermal part - possibly the theoretical spectrum is a little softer than the experimental one. In the joining region the results from THERMOS are comparatively high - probably due to the scattering model used

The Neutron Spectrum in a Uranium Tube

Energy Technology Data Exchange (ETDEWEB)

Johansson, E; Jonsson, E; Lindberg, M; Mednis, J

1963-10-15

A series of experimental and theoretical investigations on neutron spectra in lattice cells has been started at the reactor R1. This report gives the results from the first one of these cells - one with a tube of natural -uranium surrounded by heavy water. In the measurements the cell was placed in the central, vertical channel of the reactor. The neutron spectrum from a lead scatterer in the uranium tube - outer diameter 49.2 mm, inner diameter 28.3 mm - was measured with a fast chopper in the energy region 0.01 to 100 eV. Subsidiary measurements indicated that the spectrum in the beam from the lead piece corresponds to the spectrum of the angular flux integrated over all angles. This correspondence is important for the interpretation of the experimental data. The thermal part of the spectrum was found to deviate significantly from a Maxwellian. However, the deviation is not very large, and one could use a Maxwellian, at least to give a rough idea of the hardness of the spectrum. For the present tube the temperature of this Maxwellian was estimated as 90 to 100 deg C above the moderator temperature (33 deg C). In the joining region the rise of the spectrum towards the thermal part is slower than for the cell boundary spectrum, measured earlier. In the epithermal region the limited resolution of the chopper has affected the measurements at the energies of the uranium resonances. However, the shape of the spectrum on the flanks of the first resonance in {sup 238}U (6.68 eV) has been obtained accurately. In the theoretical treatment the THERMOS code with a free gas scattering model has been used. The energy region was 3.06 - 0.00025 eV. The agreement with the measurements is good for the thermal part - possibly the theoretical spectrum is a little softer than the experimental one. In the joining region the results from THERMOS are comparatively high - probably due to the scattering model used.

THE POLLUTION SPECTRUM OF OLD PESTICIDES STORAGES IN MOLDOVA

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Duca Gh.

2010-12-01

Full Text Available The old pesticide storages in Moldova showed a large quantity of polluted sites. The inventory of POPs polluted sites showed a huge number of extra high polluted sites (more 50,0 mg/kg which need the first place a remediation or other action to eliminate direct contact with people and animals. The pollution spectrum of POPs is a complex and consists of five groups: DDTs isomers, HCHs isomers, Toxaphene mixture, Chlordane and Heptachlor. The principal groups among these substances are DDTs and HCHs isomers.

Generalized eigenvalue based spectrum sensing

KAUST Repository

Shakir, Muhammad

2012-01-01

Spectrum sensing is one of the fundamental components in cognitive radio networks. In this chapter, a generalized spectrum sensing framework which is referred to as Generalized Mean Detector (GMD) has been introduced. In this context, we generalize the detectors based on the eigenvalues of the received signal covariance matrix and transform the eigenvalue based spectrum sensing detectors namely: (i) the Eigenvalue Ratio Detector (ERD) and two newly proposed detectors which are referred to as (ii) the GEometric Mean Detector (GEMD) and (iii) the ARithmetic Mean Detector (ARMD) into an unified framework of generalize spectrum sensing. The foundation of the proposed framework is based on the calculation of exact analytical moments of the random variables of the decision threshold of the respective detectors. The decision threshold has been calculated in a closed form which is based on the approximation of Cumulative Distribution Functions (CDFs) of the respective test statistics. In this context, we exchange the analytical moments of the two random variables of the respective test statistics with the moments of the Gaussian (or Gamma) distribution function. The performance of the eigenvalue based detectors is compared with the several traditional detectors including the energy detector (ED) to validate the importance of the eigenvalue based detectors and the performance of the GEMD and the ARMD particularly in realistic wireless cognitive radio network. Analytical and simulation results show that the newly proposed detectors yields considerable performance advantage in realistic spectrum sensing scenarios. Moreover, the presented results based on proposed approximation approaches are in perfect agreement with the empirical results. © 2012 Springer Science+Business Media Dordrecht.

The impact of autism spectrum disorder symptoms on gesture use in fragile X syndrome and Down syndrome

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Emily Lorang

2017-12-01

Full Text Available Background & aims This study compared gesture rate and purpose in participants with Down syndrome and fragile X syndrome, and the impact of autism spectrum disorder symptoms on each syndrome. Methods Twenty individuals with fragile X syndrome and 20 individuals with Down syndrome between nine and 22 years of age participated in this study. We coded gesture rate and purpose from an autism spectrum disorder evaluation, the Autism Diagnostic Observation Schedule – Second Edition. Results We did not find between-group differences (Down syndrome compared to fragile X syndrome in gesture rate or purpose. Notably, as autism spectrum disorder symptoms increased, the group with Down syndrome produced a lower rate of gestures, but used gestures for the same purpose. Gesture rate did not change based on autism spectrum disorder symptoms in the participants with fragile X syndrome, but as autism spectrum disorder symptoms increased, the participants with fragile X syndrome produced a larger proportion of gestures to regulate behavior and a smaller proportion for joint attention/social interaction. Conclusions Overall, the amount or purpose of gestures did not differentiate individuals with Down syndrome and fragile X syndrome. However, the presence of autism spectrum disorder symptoms had a significant and unique impact on these genetic disorders. In individuals with Down syndrome, the presence of more autism spectrum disorder symptoms resulted in a reduction in the rate of gesturing, but did not change the purpose. However, in fragile X syndrome, the rate of gestures remained the same, but the purpose of those gestures changed based on autism spectrum disorder symptoms. Implications Autism spectrum disorder symptoms differentially impact gestures in Down syndrome and fragile X syndrome. Individuals with Down syndrome and more autism spectrum disorder symptoms are using gestures less frequently. Therefore, clinicians may need to consider children with

Learning spectrum's selection in OLAM network for analysis cement samples

International Nuclear Information System (INIS)

Huang Ning; Wang Peng; Tang Daiquan; Hu Renlan

2010-01-01

It uses OLAM artificial neural network to analyze the samples of cement raw material. Two kinds of spectrums are used for network learning: pure-element spectrum and mix-element spectrum. The output of pure-element method can be used to construct a simulate spectrum, which can be compared with the original spectrum and judge the shift of spectrum; the mix-element method can store more message and correct the matrix effect, but the multicollinearity among spectrums can cause some side effect to the results. (authors)

Valuing spectrum at mm wavelengths for cellular networks

OpenAIRE

Shaw, B. A.; Beltrán, H. F.; Sowerby, K. W.

2017-01-01

This paper investigates the economic value of spectrum at mm wavelengths. The analysis uses four techniques to value spectrum, namely a benchmarking comparison, a discounted cash flow analysis, a real options approach and a deprival method. The methods to calculate spectrum value presented in this paper can be used for any spectrum band and in any country. However, to determine the value of mm wavelengths for cellular networks, we have used data from New Zealand, specifically for the existing...

What the Spectrum of Microglial Functions Can Teach us About Fetal Alcohol Spectrum Disorder

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Elissa L. Wong

2017-06-01

Full Text Available Alcohol exposure during gestation can lead to severe defects in brain development and lifelong physical, behavioral and learning deficits that are classified under the umbrella term fetal alcohol spectrum disorder (FASD. Sadly, FASD is diagnosed at an alarmingly high rate, affecting 2%–5% of live births in the United States, making it the most common non-heritable cause of mental disability. Currently, no standard therapies exist that are effective at battling FASD symptoms, highlighting a pressing need to better understand the underlying mechanisms by which alcohol affects the developing brain. While it is clear that sensory and cognitive deficits are driven by inappropriate development and remodeling of the neural circuits that mediate these processes, alcohol’s actions acutely and long-term on the brain milieu are diverse and complex. Microglia, the brain’s immune cells, have been thought to be a target for alcohol during development because of their exquisite ability to rapidly detect and respond to perturbations affecting the brain. Additionally, our view of these immune cells is rapidly changing, and recent studies have revealed a myriad of microglial physiological functions critical for normal brain development and long-term function. A clear and complete understanding of how microglial roles on this end of the spectrum may be altered in FASD is currently lacking. Such information could provide important insights toward novel therapeutic targets for FASD treatment. Here we review the literature that links microglia to neural circuit remodeling and provide a discussion of the current understanding of how developmental alcohol exposure affects microglial behavior in the context of developing brain circuits.

Earth's transmission spectrum from lunar eclipse observations.

Science.gov (United States)

Pallé, Enric; Osorio, María Rosa Zapatero; Barrena, Rafael; Montañés-Rodríguez, Pilar; Martín, Eduardo L

2009-06-11

Of the 342 planets so far discovered orbiting other stars, 58 'transit' the stellar disk, meaning that they can be detected through a periodic decrease in the flux of starlight. The light from the star passes through the atmosphere of the planet, and in a few cases the basic atmospheric composition of the planet can be estimated. As we get closer to finding analogues of Earth, an important consideration for the characterization of extrasolar planetary atmospheres is what the transmission spectrum of our planet looks like. Here we report the optical and near-infrared transmission spectrum of the Earth, obtained during a lunar eclipse. Some biologically relevant atmospheric features that are weak in the reflection spectrum (such as ozone, molecular oxygen, water, carbon dioxide and methane) are much stronger in the transmission spectrum, and indeed stronger than predicted by modelling. We also find the 'fingerprints' of the Earth's ionosphere and of the major atmospheric constituent, molecular nitrogen (N(2)), which are missing in the reflection spectrum.

Fast neutron spectrum measurement in the JMTR

International Nuclear Information System (INIS)

Sakurai, K.; Mizuho, M.

1980-01-01

Fast neutron spectrum measurement at positions of K-10 (fuel region), J-11 (first beryllium reflector region) and I-12 (second beryllium reflector region) in the JMTRC has been performed with the threshold detectors such as 107 Ag(n,n')sup(107m)Ag, 103 Rh(n,n')sup(103m)Rh, 115 In(n,n')sup(115m)In and 238 U(n,f)F.P. above 0.1 MeV energy region. The activity data have been analyzed by the unfolding code SAND-II using ANISN spectrum for initial spectrum. An effective cross section of 54 Fe(n,p) 54 Mn is calculated with Fabry's cross section data and SAND-II spectrum for K-10, J-11 and I-12. They are 76.7 mb, 69.0 mb and 68.2 mb for K-10, J-11 and I-12 respectively. These values agree with the effective cross sections (calculated by Fabry's cross section data and ANISN spectrum) within +-6%

A synthetic method of solar spectrum based on LED

Science.gov (United States)

Wang, Ji-qiang; Su, Shi; Zhang, Guo-yu; Zhang, Jian

2017-10-01

A synthetic method of solar spectrum which based on the spectral characteristics of the solar spectrum and LED, and the principle of arbitrary spectral synthesis was studied by using 14 kinds of LED with different central wavelengths.The LED and solar spectrum data were selected by Origin Software firstly, then calculated the total number of LED for each center band by the transformation relation between brightness and illumination and Least Squares Curve Fit in Matlab.Finally, the spectrum curve of AM1.5 standard solar spectrum was obtained. The results met the technical indexes of the solar spectrum matching with ±20% and the solar constant with >0.5.

Bilateral macular holes in X-linked retinoschisis: Now the spectrum is wider

Directory of Open Access Journals (Sweden)

Manoj Gautam

2011-01-01

Full Text Available Bilateral occurrence of macular hole in X-linked retinoschisis is an extremely rare event. Spectral domain optical coherence tomography (OCT findings revealed that formation of a macular hole is secondary to the retinoschisis process alone. Bilateral macular holes should be added to the spectrum of X-linked retinoschisis variations and the retinoschisis process alone should be accounted for their formation.

Molecular Spectrum Capture by Tuning the Chemical Potential of Graphene

Directory of Open Access Journals (Sweden)

Yue Cheng

2016-05-01

Full Text Available Due to its adjustable electronic properties and effective excitation of surface plasmons in the infrared and terahertz frequency range, research on graphene has attracted a great deal of attention. Here, we demonstrate that plasmon modes in graphene-coated dielectric nanowire (GNW waveguides can be excited by a monolayer graphene ribbon. What is more the transverse resonant frequency spectrum of the GNW can be flexibly tuned by adjusting the chemical potential of graphene, and amplitude of the resonance peak varies linearly with the imaginary part of the analyte permittivity. As a consequence, the GNW works as a probe for capturing the molecular spectrum. Broadband sensing of toluene, ethanol and sulfurous anhydride thin layers is demonstrated by calculating the changes in spectral intensity of the propagating mode and the results show that the intensity spectra correspond exactly to the infrared spectra of these molecules. This may open an effective avenue to design sensors for detecting nanometric-size molecules in the terahertz and infrared regimes.