Electron depletion via cathode spot dispersion of dielectric powder into an overhead plasma

International Nuclear Information System (INIS)

Gillman, Eric D.; Foster, John E.

2013-01-01

The effectiveness of cathode spot delivered dielectric particles for the purpose of plasma depletion is investigated. Here, cathode spot flows kinetically entrain and accelerate dielectric particles originally at rest into a background plasma. The time variation of the background plasma density is tracked using a cylindrical Langmuir probe biased approximately at electron saturation. As inferred from changes in the electron saturation current, depletion fractions of up to 95% are observed. This method could be exploited as a means of communications blackout mitigation for manned and unmanned reentering spacecraft as well as any high speed vehicle enveloped by a dense plasma layer

Purification, gene cloning, gene expression, and mutants of Dps from the obligate anaerobe Porphyromonas gingivalis.

Science.gov (United States)

Ueshima, Junichi; Shoji, Mikio; Ratnayake, Dinath B; Abe, Kihachiro; Yoshida, Shinichi; Yamamoto, Kenji; Nakayama, Koji

2003-03-01

The periodontopathogen Porphyromonas gingivalis is an obligate anaerobe that is devoid of catalase but exhibits a relatively high degree of resistance to peroxide stress. In the present study, we demonstrate that P. gingivalis contains a Dps homologue that plays an important role in the protection of cells from peroxide stress. The Dps protein isolated from P. gingivalis displayed a ferritin-like spherical polymer consisting of 19-kDa subunits. Molecular cloning and sequencing of the gene encoding this protein revealed that it had a high similarity in nucleotide and amino acid sequences to Dps proteins from other species. The expression of Dps was significantly increased by exposure of P. gingivalis to atmospheric oxygen in an OxyR-dependent manner, indicating that it is regulated by the reactive oxygen species-regulating gene oxyR. The Dps-deficient mutants, including the dps single mutant and the ftn dps double mutant, showed no viability loss upon exposure to atmospheric oxygen for 6 h. In contrast to the wild type, however, these mutants exhibited the high susceptibility to hydrogen peroxide, thereby disrupting the viability. On the other hand, no significant difference in sensitivity to mitomycin C and metronidazole was observed between the wild type and the mutants. Furthermore, the dps single mutant, compared with the wild type, showed a lower viability in infected human umbilical vein endothelial cells.

Determination of plasma spot current and arc discharge plasma current on the system of plasma cathode electron sources using Rogowski coil technique

International Nuclear Information System (INIS)

Wirjoadi; Bambang Siswanto; Lely Susita RM; Agus Purwadi; Sudjatmoko

2015-01-01

It has been done the function test experiments of ignitor electrode system and the plasma generator electrode system to determine the current spot plasma and arc discharge plasma current with Rogowski coil technique. Ignitor electrode system that gets power supply from IDPS system can generate the plasma spot current of 11.68 ampere to the pulse width of about 33 μs, this value is greater than the design probably because of electronic components used in the IDPS system was not as planned. For the plasma generator electrode system that gets power from ADPS system capable of producing an arc discharge plasma current around 103.15 amperes with a pulse width of about 96 μs, and this value as planned. Based on the value of the arc discharge plasma current can be determined plasma electron density, which is about 10.12 10"1"9 electrons/m"3, and with this electron density value, an ignitor electrode system and a plasma generator system is quite good if used as a plasma cathode electron source system. (author)

Effect of laser spot size on energy balance in laser induced plasmas

International Nuclear Information System (INIS)

Pant, H.C.; Sharma, S.; Bhawalkar, D.D.

1980-01-01

The effect of the laser spot size on laser light absorption in laser induced plasmas from solid targets was studied. It was found that at a constant laser intensity on the target, reduction in the laser spot size enhances the net laser energy absorption. It was also observed that the laser light reflection from the target becomes more diffused when the focal spot size is reduced

Brightness enhancement of plasma ion source by utilizing anode spot for nano applications

Energy Technology Data Exchange (ETDEWEB)

Park, Yeong-Shin; Lee, Yuna; Chung, Kyoung-Jae; Hwang, Y. S. [Department of Nuclear Engineering, Seoul National University, Seoul 151-742 (Korea, Republic of); Kim, Yoon-Jae [Samsung Electronics Co. Ltd., Gyeonggi 445-701 (Korea, Republic of); Park, Man-Jin [Research Institute of Nano Manufacturing System, Seoul National University of Science and Technology, Seoul 139-743 (Korea, Republic of); Moon, Dae Won [Nanobio Fusion Research Center, Korea Research Institute of Standards and Science, Daejeon 305-600 (Korea, Republic of)

2012-02-15

Anode spots are known as additional discharges on positively biased electrode immersed in plasmas. The anode spot plasma ion source (ASPIS) has been investigated as a high brightness ion source for nano applications such as focused ion beam (FIB) and nano medium energy ion scattering (nano-MEIS). The generation of anode spot is found to enhance brightness of ion beam since the anode spot increases plasma density near the extraction aperture. Brightness of the ASPIS has been estimated from measurement of emittance for total ion beam extracted through sub-mm aperture. The ASPIS is installed to the FIB system. Currents and diameters of the focused beams with/without anode spot are measured and compared. As the anode spot is turned on, the enhancement of beam current is observed at fixed diameter of the focused ion beam. Consequently, the brightness of the focused ion beam is enhanced as well. For argon ion beam, the maximum normalized brightness of 12 300 A/m{sup 2} SrV is acquired. The ASPIS is applied to nano-MEIS as well. The ASPIS is found to increase the beam current density and the power efficiency of the ion source for nano-MEIS. From the present study, it is shown that the ASPIS can enhance the performance of devices for nano applications.

Modes of Escherichia coli Dps Interaction with DNA as Revealed by Atomic Force Microscopy.

Directory of Open Access Journals (Sweden)

Vladislav V Melekhov

Full Text Available Multifunctional protein Dps plays an important role in iron assimilation and a crucial role in bacterial genome packaging. Its monomers form dodecameric spherical particles accumulating ~400 molecules of oxidized iron ions within the protein cavity and applying a flexible N-terminal ends of each subunit for interaction with DNA. Deposition of iron is a well-studied process by which cells remove toxic Fe2+ ions from the genetic material and store them in an easily accessible form. However, the mode of interaction with linear DNA remained mysterious and binary complexes with Dps have not been characterized so far. It is widely believed that Dps binds DNA without any sequence or structural preferences but several lines of evidence have demonstrated its ability to differentiate gene expression, which assumes certain specificity. Here we show that Dps has a different affinity for the two DNA fragments taken from the dps gene regulatory region. We found by atomic force microscopy that Dps predominantly occupies thermodynamically unstable ends of linear double-stranded DNA fragments and has high affinity to the central part of the branched DNA molecule self-assembled from three single-stranded oligonucleotides. It was proposed that Dps prefers binding to those regions in DNA that provide more contact pads for the triad of its DNA-binding bundle associated with one vertex of the protein globule. To our knowledge, this is the first study revealed the nucleoid protein with an affinity to branched DNA typical for genomic regions with direct and inverted repeats. As a ubiquitous feature of bacterial and eukaryotic genomes, such structural elements should be of particular care, but the protein system evolutionarily adapted for this function is not yet known, and we suggest Dps as a putative component of this system.

Ion distribution in the hot spot of an inertial confinement fusion plasma

Science.gov (United States)

Tang, Xianzhu; Guo, Zehua; Berk, Herb

2012-10-01

Maximizing the fusion gain of inertial confinement fusion (ICF) for inertial fusion energy (IFE) applications leads to the standard scenario of central hot spot ignition followed by propagating burn wave through the cold/dense assembled fuel. The fact that the hot spot is surrounded by cold but dense fuel layer introduces subtle plasma physics which requires a kinetic description. Here we perform Fokker-Planck calculations and kinetic PIC simulations for an ICF plasma initially in pressure balance but having large temperature gradient over a narrow transition layer. The loss of the fast ion tail from the hot spot, which is important for fusion reactivity, is quantified by Fokker-Planck models. The role of electron energy transport and the ambipolar electric field is investigated via kinetic simulations and the fluid moment models. The net effect on both hot spot ion temperature and the ion tail distribution, and hence the fusion reactivity, is elucidated.

Hot spots and dark current in advanced plasma wakefield accelerators

Directory of Open Access Journals (Sweden)

G. G. Manahan

2016-01-01

Full Text Available Dark current can spoil witness bunch beam quality and acceleration efficiency in particle beam-driven plasma wakefield accelerators. In advanced schemes, hot spots generated by the drive beam or the wakefield can release electrons from higher ionization threshold levels in the plasma media. These electrons may be trapped inside the plasma wake and will then accumulate dark current, which is generally detrimental for a clear and unspoiled plasma acceleration process. Strategies for generating clean and robust, dark current free plasma wake cavities are devised and analyzed, and crucial aspects for experimental realization of such optimized scenarios are discussed.

The Influence of spot size on the expansion dynamics of nanosecond-laser-produced copper plasmas in atmosphere

International Nuclear Information System (INIS)

Li, Xingwen; Wei, Wenfu; Wu, Jian; Jia, Shenli; Qiu, Aici

2013-01-01

Laser produced copper plasmas of different spot sizes in air were investigated using fast photography and optical emission spectroscopy (OES). The laser energy was 33 mJ. There were dramatic changes in the plasma plume expansion into the ambient air when spot sizes changed from ∼0.1 mm to ∼0.6 mm. A stream-like structure and a hemispherical structure were, respectively, observed. It appeared that the same spot size resulted in similar expansion dynamics no matter whether the target was located in the front of or behind the focal point, although laser-induced air breakdown sometimes occurred in the latter case. Plasma plume front positions agree well with the classic blast wave model for the large spot-size cases, while an unexpected stagnation of ∼80 ns occurred after the laser pulse ends for the small spot size cases. This stagnation can be understood in terms of the evolution of enhanced plasma shielding effects near the plasma front. Axial distributions of plasma components by OES revealed a good confinement effect. Electron number densities were estimated and interpreted using the recorded Intensified Charge Coupled Device (ICCD) images.

77 FR 23209 - Endangered and Threatened Species; Proposed Delisting of Eastern DPS of Steller Sea Lions

Science.gov (United States)

2012-04-18

... of these fisheries are not likely to cause the eastern DPS to become in danger of extinction in the... coastal habitats is likely to cause the eastern DPS of Steller sea lion to become in danger of extinction... likely to cause the eastern DPS of Steller sea lions to become in danger of extinction in the foreseeable...

Time and space resolved observation of hot spots in a plasma focus

International Nuclear Information System (INIS)

Choi, P.; Aliaga, R.; Herold, H.

1990-01-01

The authors report some recent results on the time and space evolution of hot spots on the DPF-78 plasma focus at the University of Stuttgart. The experiments were carried out in mixtures of deuterium and krypton at a bank voltage of 60 kV and a stored energy of 28 kJ. A modification of the ADRRM streak technique carried out in the soft x-ray region allowed us to directly examine some characteristics of the hot spots. Simultaneous measurements were carried out on the hard x-ray radiation (80 keV), the spatially resolved optical emissions, the neutron yield rate with TOF information and the plasma and bank currents

OxyR-activated expression of Dps is important for Vibrio cholerae oxidative stress resistance and pathogenesis.

Directory of Open Access Journals (Sweden)

Xiaoyun Xia

Full Text Available Vibrio cholerae is the causative agent of cholera, a dehydrating diarrheal disease. This Gram-negative pathogen is able to modulate its gene expression in order to combat stresses encountered in both aquatic and host environments, including stress posed by reactive oxygen species (ROS. In order to further the understanding of V. cholerae's transcriptional response to ROS, we performed an RNA sequencing analysis to determine the transcriptional profile of V. cholerae when exposed to hydrogen hydroperoxide. Of 135 differentially expressed genes, VC0139 was amongst the genes with the largest induction. VC0139 encodes a protein homologous to the DPS (DNA-binding protein from starved cells protein family, which are widely conserved and are implicated in ROS resistance in other bacteria. Using a promoter reporter assay, we show that during exponential growth, dps is induced by H2O2 in a manner dependent on the ROS-sensing transcriptional regulator, OxyR. Upon entry into stationary phase, the major stationary phase regulator RpoS is required to transcribe dps. Deletion of dps impaired V. cholerae resistance to both inorganic and organic hydroperoxides. Furthermore, we show that Dps is involved in resistance to multiple environmental stresses. Finally, we found that Dps is important for V. cholerae adult mouse colonization, but becomes dispensable in the presence of antioxidants. Taken together, our results suggest that Dps plays vital roles in both V. cholerae stress resistance and pathogenesis.

Dps promotes survival of nontypeable Haemophilus influenzae in biofilm communities in vitro and resistance to clearance in vivo.

Science.gov (United States)

Pang, Bing; Hong, Wenzhou; Kock, Nancy D; Swords, W Edward

2012-01-01

Nontypeable Haemophilus influenzae (NTHi) is a common airway commensal and opportunistic pathogen that persists within surface-attached biofilm communities. In this study, we tested the hypothesis that bacterial stress-responses are activated within biofilms. Transcripts for several factors associated with bacterial resistance to environmental stress were increased in biofilm cultures as compared to planktonic cultures. Among these, a homolog of the DNA-binding protein from starved cells (dps) was chosen for further study. An isogenic NTHi 86-028NP dps mutant was generated and tested for resistance to environmental stress, revealing a significant survival defects in high-iron conditions, which was mediated by oxidative stress and was restored by genetic complementation. As expected, NTHi 86-028NP dps had a general stress-response defect, exhibiting decreased resistance to many types of environmental stress. While no differences were observed in density and structure of NTHi 86-028NP and NTHi 86-028NP dps biofilms, bacterial survival was decreased in NTHi 86-028NP dps biofilms as compared to the parental strain. The role of dps persistence in vivo was tested in animal infection studies. NTHi 86-028NP dps had decreased resistance to clearance after pulmonary infection of elastase-treated mice as compared to NTHi 86-028NP, whereas minimal differences were observed in clearance from mock-treated mice. Similarly, lower numbers of NTHi 86-028NP dps were recovered from middle-ear effusions and bullar homogenates in the chinchilla model for otitis media (OM). Therefore, we conclude that Dps promotes bacterial survival within NTHi biofilm communities both in vitro and in chronic infections in vivo.

Dps promotes survival of nontypeable Haemophilus influenzae in biofilm communities in vitro and resistance to clearance in vivo

Directory of Open Access Journals (Sweden)

Bing ePang

2012-05-01

Full Text Available Nontypeable Haemophilus influenzae (NTHi is a common airway commensal and opportunistic pathogen that persists within surface-attached biofilm communities. In this study, we tested the hypothesis that bacterial stress-responses are activated within biofilms. Transcripts for several factors associated with bacterial resistance to environmental stress were increased in biofilm cultures as compared to planktonic cultures. Among these, a homolog of the DNA-binding protein from starved cells (dps was chosen for further study. An isogenic NTHi 86-028NP dps mutant was generated and tested for resistance to environmental stress, revealing a significant survival defects in high-iron conditions, which was mediated by oxidative stress and was restored by genetic complementation. As expected, NTHi 86-028NP dps had a general stress-response defect, exhibiting decreased resistance to many types of environmental stress. While no differences were observed in density and structure of NTHi 86-028NP and NTHi 86-028NP dps biofilms, bacterial survival was decreased in NTHi 86-028NP dps biofilms as compared to the parental strain. The role of dps persistence in vivo was tested in animal infection studies. NTHi 86-028NP dps had decreased resistance to clearance after pulmonary infection of elastase-treated mice as compared to NTHi 86-028NP, whereas minimal differences were observed in clearance from mock-treated mice. Similarly, lower numbers of NTHi 86-028NP dps were recovered from middle-ear effusions and bullar homogenates in the chinchilla model for otitis media. Therefore, we conclude that Dps promotes bacterial survival within NTHi biofilm communities both in vitro and in chronic infections in vivo.

Dependence of high order harmonics intensity on laser focal spot position in preformed plasma plumes

International Nuclear Information System (INIS)

Singhal, H.; Ganeev, R.; Naik, P. A.; Arora, V.; Chakravarty, U.; Gupta, P. D.

2008-01-01

The dependence of the high-order harmonic intensity on the laser focal spot position in laser produced plasma plumes is experimentally studied. High order harmonics up to the 59th order (λ∼13.5 nm) were generated by focusing 48 fs laser pulses from a Ti:sapphire laser system in silver plasma plume produced using 300 ps uncompressed laser radiation as the prepulse. The intensity of harmonics nearly vanished when the best focus was located in the plume center, whereas it peaked on either side with unequal intensity. The focal spot position corresponding to the peak harmonic intensity moved away from the plume center for higher order harmonics. The results are explained in terms of the variation of phase mismatch between the driving laser beam and harmonics radiation produced, relativistic drift of electrons, and defocusing effect due to radial ionization gradient in the plasma for different focal spot positions

Diffusion in plasma: The Hall effect, compositional waves, and chemical spots

Energy Technology Data Exchange (ETDEWEB)

Urpin, V., E-mail: Vadim.urpin@uv.es [Ioffe Institute of Physics and Technology (Russian Federation)

2017-03-15

Diffusion caused by a combined influence of the electric current and Hall effect is considered, and it is argued that such diffusion can form inhomogeneities of a chemical composition in plasma. The considered mechanism can be responsible for the formation of element spots in laboratory and astrophysical plasmas. This current-driven diffusion can be accompanied by propagation of a particular type of waves in which the impurity number density oscillates alone. These compositional waves exist if the magnetic pressure in plasma is much greater than the gas pressure.

Hot spots and filaments in the pinch of a plasma focus: a unified approach

International Nuclear Information System (INIS)

Di Vita, A.

2009-01-01

To date, no MHD-based complete description of the tiny, relatively stable, well-ordered structures (hot spots, filaments) observed in the pinch of a plasma focus seems to be feasible. Indeed, the large value of electron density suggests that a classification of such structures which is based on the approximation of local thermodynamical equilibrium (LTE) is possible. Starting from an often overlooked, far-reaching result of LTE, we derive a purely analytical description of both hot spots and filaments. In spite of their quite different topology, both configurations are extrema of the same variational principle. Well-known results of conventional MHD are retrieved as benchmark cases. It turns out that hot spots satisfy Taylor's principle of constrained minimum of magnetic energy, the constraint being given by fixed magnetic helicity. Filaments are similar to the filaments of a superconductor and form a plasma with β equals 0.11 and energy diffusion coefficient equals 0.88*D(Bohm). Any process - like e.g. radiative collapse - which raises particle density while reducing radial size may transform filaments into hot spots. A well-known scaling law is retrieved - the collisional Vlasov high beta scaling. A link between dissipation and topology is highlighted. Accordingly, a large-current pinch may give birth to tiny hot spots with large electron density and magnetic field. (author)

Numerical studies of third-harmonic generation in laser filament in air perturbed by plasma spot

International Nuclear Information System (INIS)

Feng Liubin; Lu Xin; Liu Xiaolong; Li Yutong; Chen Liming; Ma Jinglong; Dong Quanli; Wang Weimin; Xi Tingting; Sheng Zhengming; Zhang Jie; He Duanwei

2012-01-01

Third-harmonic emission from laser filament intercepted by plasma spot is studied by numerical simulations. Significant enhancement of the third-harmonic generation is obtained due to the disturbance of the additional plasma. The contribution of the pure plasma effect and the possible plasma-enhanced third-order susceptibility on the third-harmonic generation enhancement are compared. It is shown that the plasma induced cancellation of destructive interference [Y. Liu et al., Opt. Commun. 284, 4706 (2011)] of two-colored filament is the dominant mechanism of the enhancement of third-harmonic generation.

Initial development of ponderomotive filaments in plasma from intense hot spots produced by a random phase plate

International Nuclear Information System (INIS)

Rose, H.A.; DuBois, D.F.

1993-01-01

Local intensity peaks, hot spots, in laser beams may initiate self-focusing, in lieu of linear instabilities. If the hot spot power, P, contains several times the critical power, P c , and if the plasma density, n, is small compared to the critical density, n c , then on a time scale less than an acoustic transit time across the hot spot radius, τ ia , the hot spot collapses, capturing order unity of the initial hot spot power. The collapse time is determined as a universal function of P/P c and τ ia . The focal region moves towards the laser with an initially supersonic speed, and decelerates as it propagates. The power of this back propagating focus decreases monotonically until the critical power is reached. This limiting, shallowest, focus develops on a time scale long compared to τ ia and corresponds to the focus obtained in a model with adiabatically responding ions. For low-density plasma nonlinear ion effects terminate collapse and a bound on the transient intensity amplification is obtained as a universal function of the optics f/number, F, and n/n c . The boundary between thermal and ponderomotive regimes depends upon F and not the laser intensity

How NASA's Space Science Support Network Can Assist DPS Members in Their Public Engagement Efforts

Science.gov (United States)

Miner, E. D.; Lowes, L. L.

2003-12-01

In her Carl Sagan Medal lecture last year, Heidi Hammel talked of the dos and don'ts of education and public outreach efforts by DPS members. She pointed out a number of misconceptions about what does and does not constitute "good EPO" and encouraged members to consult with "the experts" if they would like to improve their EPO effectiveness and reach. She named the DPS Education and Public Outreach Officer, Larry Lebofsky, his Deputy, Lou Mayo, and the DPS Press Officer, Ellis Miner, who also co-directs NASA's Solar System Exploration EPO Forum with Leslie Lowes. NASA's Space Science Support Network has been in existence for about six years. It has been directed by DPS member Jeff Rosendhal and is now serving as a model for NASA's new Education Enterprise. Members of the Support Network are prepared to assist (and haves been assisting) space scientists throughout the US and abroad in deciding where to spend their EPO efforts most effectively. The service is provided free of cost and includes, among other services, the following: (1) helping to establish partnerships between educators and scientists, (2) helping to link scientists and professional EPO organizations, (3) helping to link scientists to national youth and community groups, (4) providing ready access to EPO electronic and hardcopy products, (5) providing advice and direction in the preparation of EPO proposals to NASA, (6) helping to maintain several national networks of EPO volunteers, (7) encouraging (at home institutions) the broadening of scientist EPO efforts, (8) maintaining self-help websites for scientists interested in EPO.

Periplasmic Cu,Zn superoxide dismutase and cytoplasmic Dps concur in protecting Salmonella enterica serovar Typhimurium from extracellular reactive oxygen species.

Science.gov (United States)

Pacello, Francesca; Ceci, Pierpaolo; Ammendola, Serena; Pasquali, Paolo; Chiancone, Emilia; Battistoni, Andrea

2008-02-01

Several bacteria possess periplasmic Cu,Zn superoxide dismutases which can confer protection from extracellular reactive oxygen species. Thus, deletion of the sodC1 gene reduces Salmonella enterica serovar Typhimurium ability to colonize the spleens of wild type mice, but enhances virulence in p47phox mutant mice. To look into the role of periplamic Cu,Zn superoxide dismutase and into possible additive effects of the ferritin-like Dps protein involved in hydrogen peroxide detoxification, we have analyzed bacterial survival in response to extracellular sources of superoxide and/or hydrogen peroxide. Exposure to extracellular superoxide of Salmonella Typhimurium mutant strains lacking the sodC1 and sodC2 genes and/or the dps gene does not cause direct killing of bacteria, indicating that extracellular superoxide is poorly bactericidal. In contrast, all mutant strains display a sharp hydrogen peroxide-dependent loss of viability, the dps,sodC1,sodC2 mutant being less resistant than the dps or the sodC1,sodC2 mutants. These findings suggest that the role of Cu,Zn superoxide dismutase in bacteria is to remove rapidly superoxide from the periplasm to prevent its reaction with other reactive molecules. Moreover, the nearly additive effect of the sodC and dps mutations suggests that localization of antioxidant enzymes in different cellular compartments is required for bacterial resistance to extracytoplasmic oxidative attack.

Kineococcus radiotolerans Dps forms a heteronuclear Mn-Fe ferroxidase center that may explain the Mn-dependent protection against oxidative stress.

Science.gov (United States)

Ardini, Matteo; Fiorillo, Annarita; Fittipaldi, Maria; Stefanini, Simonetta; Gatteschi, Dante; Ilari, Andrea; Chiancone, Emilia

2013-06-01

The ferroxidase center of DNA-binding protein from starved cells (Dps) is a major player in the iron oxidation/detoxification process that leads to a decreased reactive oxygen species production. The possible Mn(II) participation in this process has been studied in Dps from Kineococcus radiotolerans, a radiation-resistant bacterium with a high cytosolic Mn/Fe ratio and a high capacity to survive ionizing and stress conditions. The X-ray structure of recombinant K. radiotolerans Dps loaded with Mn(II) has been solved at 2.0Å resolution. Mn(II) binding to K. radiotolerans Dps and its effect on Fe(II) oxidation have been characterized in spectroscopic measurements. In K. radiotolerans Dps, the Fe-Fe ferroxidase center can have a Mn-Fe composition. Mn(II) binds only at the high affinity, so-called A site, whereas Fe(II) binds also at the low affinity, so-called B site. The Mn-Fe and Fe-Fe centers behave distinctly upon iron oxidation by O2. A site-bound Mn(II) or Fe(II) plays a catalytic role, while B site-bound Fe(II) behaves like a substrate and can be replaced by another Fe(II) after oxidation. When H2O2 is the Fe(II) oxidant, single electrons are transferred to aromatic residues near the ferroxidase center and give rise to intra-protein radicals thereby limiting OH release in solution. The presence of the Mn-Fe center results in significant differences in the development of such intra-protein radicals. Mn(II) bound at the Dps ferroxidase center A site undergoes redox cycling provided the B site contains Fe. The results provide a likely molecular mechanism for the protective role of Mn(II) under oxidative stress conditions as it participates in redox cycling in the hetero-binuclear ferroxidase center. Copyright © 2013 Elsevier B.V. All rights reserved.

Preliminary Results from a Survey of DPS Scientist’s Attitudes, Activities and Needs in Education and Public Outreach

Science.gov (United States)

Grier, Jennifer A.; Buxner, Sanlyn; Schneider, Nick

2014-11-01

The NASA SMD Planetary Sciences Forum, in partnership with the AAS DPS Education officer has conducted a semi-structured series of interviews with two-dozen DPS members to ascertain: the nature E/PO activities pursued by scientists, what resources and professional development opportunities are needed by scientists, how to increase the impact of scientists’ E/PO efforts, scientists’ concerns and questions regarding E/PO, and what we can do to identify opportunities to address these issues, both from the SMD and DPS perspectives. Members were contacted by phone, and responded to a loose script of questions over a time span of 20 to 90 minutes, depending on the individual. Members were chosen to represent a variety of career experience, home institutions and affiliations, and level of involvement with E/PO. Questions included: What is your level of involvement in E/PO? What sort of professional development or resources would you like to have to increase the efficiency of your E/PO efforts? What barriers to E/PO involvement have you encountered? How do you use social media in your E/PO efforts, if at all? What are your motivations for involvement in E/PO? etc. Our results are consistent with previous research conducted regarding this issue, but they do offer insight specific to the nature of DPS members and their views about E/PO. We will present a subset of these results, the opportunities they present, and the responses of both the PS Forum and the DPS. Based on this survey, the SMD PS Forum was able to identify specific new resources needed by scientists, and therefore developed the brief-one page guides, “The Quick Introduction to Education and Public Outreach,” and “Making the Most of Your E/PO Time - Increasing Your Efficiency and Impact.” Further resources and professional development opportunities will be developed as the data continue to be reviewed. This data collection effort is ongoing. If you would like to become involved, contact Jennifer

Synthesis of iron oxide nanoparticles in Listeria innocua Dps (DNA-binding protein from starved cells): a study with the wild-type protein and a catalytic centre mutant.

Science.gov (United States)

Ceci, Pierpaolo; Chiancone, Emilia; Kasyutich, Oksana; Bellapadrona, Giuliano; Castelli, Lisa; Fittipaldi, Maria; Gatteschi, Dante; Innocenti, Claudia; Sangregorio, Claudio

2010-01-11

A comparative analysis of the magnetic properties of iron oxide nanoparticles grown in the cavity of the DNA-binding protein from starved cells of the bacterium Listeria innocua, LiDps, and of its triple-mutant lacking the catalytic ferroxidase centre, LiDps-tm, is presented. TEM images and static and dynamic magnetic and electron magnetic resonance (EMR) measurements reveal that, under the applied preparation conditions, namely alkaline pH, high temperature (65 degrees C), exclusion of oxygen, and the presence of hydrogen peroxide, maghemite and/or magnetite nanoparticles with an average diameter of about 3 nm are mineralised inside the cavities of both LiDps and LiDps-tm. The magnetic nanoparticles (MNPs) thus formed show similar magnetic properties, with superparamagnetic behaviour above 4.5 K and a large magnetic anisotropy. Interestingly, in the EMR spectra an absorption at half-field is observed, which can be considered as a manifestation of the quantum behaviour of the MNPs. These results indicate that Dps proteins can be advantageously used for the production of nanomagnets at the interface between molecular clusters and traditional MNPs and that the presence of the ferroxidase centre, though increasing the efficiency of nanoparticle formation, does not affect the nature and fine structure of the MNPs. Importantly, the self-organisation of MNP-containing Dps on HRTEM grids suggests that Dps-enclosed MNPs can be deposited on surfaces in an ordered fashion.

Gyrocenter Shift of Low-Temperature Plasmas and the Retrograde Motion of Cathode Spots in Arc Discharges

International Nuclear Information System (INIS)

Lee, K. C.

2007-01-01

The gyrocenter shift phenomenon explained the mechanism of radial electric field formation at the high confinement mode transition in fusion devices. This Letter reports that the theory of gyrocenter shift is also applicable to low temperature high collisional plasmas such as arc discharges by the generalization of the theory resulting from a short mean free path compared with the gyroradius. The retrograde motion of cathode spots in the arc discharge is investigated through a model with the expanded formula of gyrocenter shift. It is found that a reversed electric field is formed in front of the cathode spots when they are under a magnetic field, and this reversed electric field generates a rotation of cathode spots opposite to the Amperian direction. The ion drift velocity profiles calculated from the model are in agreement with the experimental results as functions of magnetic flux density and gas pressure

Hot spot formation on different tokamak wall materials

International Nuclear Information System (INIS)

Nedospasov, A.V.; Bezlyudny, I.V.

1998-01-01

The thermal contraction phenomenon and generation of 'hot spots' due to thermoemission were described. The paper consider non-linear stages of heat contraction on the graphite, beryllium, tungsten and vanadium wall. It is shown that on the beryllium surface hot spot can't appear due to strong cooling by sublimation. For other materials the conditions of hot spot appearance due to local superheating of the wall have been calculated and their parameters were found: critical surface temperature, size of spots and their temperature profiles, heat fluxes from plasma to the spots. It have been calculated fluxes of sublimating materials from spots to the plasma. It is noticed that nominal temperature of the grafite divertor plate, accepted in ITER's project to being equal 1500 C, is lower then critical temperature of the development heat contraction due to thermoemission. (orig.)

Measurements of hot spots and electron beams in Z-pinch devices

International Nuclear Information System (INIS)

Deeney, C.

1988-04-01

Hot spots and Electron Beams have been observed in different types of Z-pinches. There is, however, no conclusive evidence on how either are formed although there has been much theoretical interest in both these phenomena. In this thesis, nanosecond time resolved and time correlated, X-ray and optical diagnostics, are performed on two different types of Z-pinch: a 4 kJ, 30 kV Gas Puff Z-pinch and a 28 kJ, 60 kV Plasma Focus. The aim being to study hot spots and electron beams, as well as characterise the plasma, two different Z-pinch devices. Computer codes are developed to analyse the energy and time resolved data obtained in this work. These codes model both, X-ray emission from a plasma and X-ray emission due to electron beam bombardment of a metal surface. The hot spot and electron beam parameters are measured, from the time correlated X-ray data using these computer codes. The electron beams and the hot spots are also correlated to the plasma behaviour and to each other. The results from both devices are compared with each other and with the theoretical work on hot spot and electron beam formation. A previously unreported 3-5 keV electron temperature plasma is identified, in the gas puff Z-pinch plasma, prior to the formation of the hot spots. it is shown, therefore, that the hot spots are more dense but not hotter than the surrounding plasma. Two distinct periods of electron beam generation are identified in both devices. (author)

Expansion of the cathode spot and generation of shock waves in the plasma of a volume discharge in atmospheric-pressure helium

International Nuclear Information System (INIS)

Omarov, O. A.; Kurbanismailov, V. S.; Arslanbekov, M. A.; Gadzhiev, M. Kh.; Ragimkhanov, G. B.; Al-Shatravi, Ali J. G.

2012-01-01

The expansion of the cathode spot and the generation of shock waves during the formation and development of a pulsed volume discharge in atmospheric-pressure helium were studied by analyzing the emission spectra of the cathode plasma and the spatiotemporal behavior of the plasma glow. The transition of a diffuse volume discharge in a centimeter-long gap into a high-current diffuse mode when the gas pressure increased from 1 to 5 atm and the applied voltage rose from the statistical breakdown voltage to a 100% overvoltage was investigated. Analytical expressions for the radius of the cathode spot and its expansion velocity obtained in the framework of a spherically symmetric model agree satisfactorily with the experimental data.

Models of spots and flares

International Nuclear Information System (INIS)

Mullan, D.J.

1983-01-01

Laboratory experiments in recent years have shown that there are many more ways to drive a plasma out of equilibrium than to preserve equilibrium. In that sense, it is perhaps easier to understand why flares should occur in a stellar atmosphere than why a long-lived feature such as a dark spot should persist. The author summarizes work on the equilibrium structure of cool spots in the sun and stars. Since spots involve complex interactions between convective flows and magnetic fields, he needs to refer to observations for help in identifying the dominant processes which should enter into the modelling. His summary therefore begins by discussing certain relevant properties of spots in the solar atmosphere. The next sections deal with the magnetic fields in spots, the stability of spots, spot cooling and missing flux. The author concludes that spots should be viewed not simply as cool areas, but rather as engines which do the work of converting the energy of convective flows into flare-compatible form. (Auth.)

DPS Planetary Science Graduate Programs Database for Students and Advisors

Science.gov (United States)

Klassen, David R.; Roman, Anthony; Meinke, Bonnie K.

2017-10-01

Planetary science is a topic that covers an extremely diverse set of disciplines; planetary scientists are typically housed in a departments spanning a wide range of disciplines. As such it is difficult for undergraduate students to find programs that will give them a degree and research experience in our field as Department of Planetary Science is a rare sighting, indeed. Not only can this overwhelm even the most determined student, it can even be difficult for many undergraduate advisers.Because of this, the DPS Education committee decided several years ago that it should have an online resource that could help undergraduate students find graduate programs that could lead to a PhD with a focus in planetary science. It began in 2013 as a static page of information and evolved from there to a database-driven web site. Visitors can browse the entire list of programs or create a subset listing based on several filters. The site should be of use not only to undergraduates looking for programs, but also for advisers looking to help their students decide on their future plans. We present here a walk-through of the basic features as well as some usage statistics from the collected web site analytics. We ask for community feedback on additional features to make the system more usable for them. We also call upon those mentoring and advising undergraduates to use this resource, and for program admission chairs to continue to review their entry and provide us with the most up-to-date information.The URL for our site is http://dps.aas.org/education/graduate-schools.

Coevolution of aah: A dps-Like Gene with the Host Bacterium Revealed by Comparative Genomic Analysis

Directory of Open Access Journals (Sweden)

Liyan Ping

2012-01-01

Full Text Available A protein named AAH was isolated from the bacterium Microbacterium arborescens SE14, a gut commensal of the lepidopteran larvae. It showed not only a high sequence similarity to Dps-like proteins (DNA-binding proteins from starved cell but also reversible hydrolase activity. A comparative genomic analysis was performed to gain more insights into its evolution. The GC profile of the aah gene indicated that it was evolved from a low GC ancestor. Its stop codon usage was also different from the general pattern of Actinobacterial genomes. The phylogeny of dps-like proteins showed strong correlation with the phylogeny of host bacteria. A conserved genomic synteny was identified in some taxonomically related Actinobacteria, suggesting that the ancestor genes had incorporated into the genome before the divergence of Micrococcineae from other families. The aah gene had evolved new function but still retained the typical dodecameric structure.

Plasma parameters of the cathode spot explosive electron emission cell obtained from the model of liquid-metal jet tearing and electrical explosion

Science.gov (United States)

Tsventoukh, M. M.

2018-05-01

A model has been developed for the explosive electron emission cell pulse of a vacuum discharge cathode spot that describes the ignition and extinction of the explosive pulse. The pulse is initiated due to hydrodynamic tearing of a liquid-metal jet which propagates from the preceding cell crater boundary and draws the ion current from the plasma produced by the preceding explosion. Once the jet neck has been resistively heated to a critical temperature (˜1 eV), the plasma starts expanding and decreasing in density, which corresponds to the extinction phase. Numerical and analytical solutions have been obtained that describe both the time behavior of the pulse plasma parameters and their average values. For the cell plasma, the momentum per transferred charge has been estimated to be some tens of g cm/(s C), which is consistent with the known measurements of ion velocity, ion erosion rate, and specific recoil force. This supports the model of the pressure-gradient-driven plasma acceleration mechanism for the explosive cathode spot cells. The ohmic electric field within the explosive current-carrying plasma has been estimated to be some tens of kV/cm, which is consistent with the known experimental data on cathode potential fall and explosive cell plasma size. This supports the model that assumes the ohmic nature of the cathode potential fall in a vacuum discharge.

[Study on Hexagonal Super-Lattice Pattern with Light Spot and Dim Spot in Dielectric Barrier Discharge by Optical Emission Spectra].

Science.gov (United States)

Liu, Ying; Dong, Li-fang; Niu, Xue-jiao; Zhang, Chao

2016-02-01

The hexagonal super-lattice pattern composed of the light spot and the dim spot is firstly observed and investigated in the discharge of gas mixture of air and argon by using the dielectric barrier discharge device with double water electrodes. It is found that the dim spot is located at the center of its surrounding three light spots by observing the discharge image. Obviously, the brightness of the light spot and the dim spot are different, which indicates that the plasma states of the light spot and the dim spot may be different. The optical emission spectrum method is used to further study the several plasma parameters of the light spot and the dim spot in different argon content. The emission spectra of the N₂ second positive band (C³IIu --> B³IIg) are measured, from which the molecule vibration temperatures of the light spot and the dim spot are calculated. Based on the relative intensity ratio of the line at 391.4 nm and the N₂ line at 394.1 nm, the average electron energies of the light spot and the dim spot are investigated. The broadening of spectral line 696.57 nm (2P₂-1S₅) is used to study the electron densities of the light spot and the dim spot. The experiment shows that the molecule vibration temperature, average electron energy and the electron density of the dim spot are higher than those of the light spot in the same argon content. The molecule vibration temperature and electron density of the light spot and dim spot increase with the argon content increasing from 70% to 95%, while average electron energies of the light spot and dim spot decrease gradually. The short-exposure image recorded by a high speed video camera shows that the dim spot results from the surface discharges (SDs). The surface discharge induced by the volume discharge (VD) has the decisive effect on the formation of the dim spot. The experiment above plays an important role in studying the formation mechanism of the hexagonal super-lattice pattern with light spot and

The Potomac Experience - a forerunner of DPS

International Nuclear Information System (INIS)

Steiner, R.C.

1993-01-01

Thirty years ago, dramatic events were about to begin in Potomac River basin with the publication of a report of study recommending 16 major reservoirs and hundreds of small ones to solve the foreseeable water supply problems in the basin, especially those of the Washington metropolitan area. The proposed solution was confounded by its shear size, the emergence of an era of more critical thinking, and the growing development of more sophisticated analytical tools. When viewed from the perspective of the current Drought Preparedness Studies, the Potomac Experience does seem in some senses to have been a forerunner. Among the greatest similarities is the simultaneous consideration of demands and resource availability on an operational time step with the aid of computer modelling. Other contributions to the success on the Potomac which are hoped to be included in the DPS include: involvement of local elected officials and citizens groups, technical input from the affected water utilities, creative use of analytical techniques, and the dedicated commitment of the project leadership

Discovery of the Electronic Spectra of Hps and Dps

Science.gov (United States)

Grimminger, Robert A.; Wei, Jie; Ellis, Blaine; Clouthier, Dennis J.; Wang, Zhong; Sears, Trevor

2009-06-01

The hitherto unknown electronic spectrum of the closed shell transient molecule HPS has been observed in the 685 - 846 nm region by laser-induced fluorescence and single vibronic level emission techniques. HPS (and DPS) were produced in a pulsed electric discharge jet using a precursor mixture of 3% PH_3 and 1% H_2S (or PD_3 and D_2S) in high pressure argon. The weak set of observed bands are assigned to the à ^1A^''-X˜ ^1A^' electronic transition on the basis of chemical evidence, isotope shifts and the correspondence of the vibrational frequencies, excitation energy, and band contours with predictions based on our own high level ab initio calculations. Theory predicts that the HPS bond angle decreases on electronic excitation, contrary to expectations based on Walsh diagrams.

Studies of Hot Spots in Imploding Wire Arrays at 1 MA on COBRA

International Nuclear Information System (INIS)

Pikuz, Sergey A.; Shelkovenko, Tatiana A.; McBride, Ryan D.; Hammer, David A.

2009-01-01

We present recent results from hot spot investigations in imploding Al wire array z-pinches on the COBRA generator at Cornell University using x-ray diagnostics. Measurements of the temporal and spatial distribution of hot spots in stagnating plasmas by an x-ray streak-camera are included. Experiments show that hot spots have nanosecond lifetime and appear randomly along the array axis after plasma stagnation in secondary pinches in 8 mm diameter and during plasma stagnation in the arrays with 4 mm diameter.

Data verification of a hardware-software complex of sounding an ionosphere and ionosonde DPS-4

Science.gov (United States)

Smirnov, Vladimir; Ruzhin, Yuri; Smirnova, Elena; Skobelkin, Vladimir; Tynyankin, Sergey

Appeared in recent years, opportunities to use as a source of signals used to determine the parameters of the ionosphere, the spacecraft global navigation satellite systems GLONASS and GPS are not currently in widespread use practices ionospheric wave frequency and radio centers and dispatch services. Given the urgency of the discussed areas of research, long experiment whose purpose is to conduct a comparative analysis of the results of determining the critical frequency of F2-layer of the ionosphere in two ways - vertical sounding (ionosonde DPS-4) and radio translucence track "satellite-the Earth" with signals using GLONASS satellites and GPS was started in 2013. For a comparative analysis of the results the hardware-software complex ionospheric soundings (HSCIS) was located at territory of the Pushkov Institute of Terrestrial Magnetism, Ionosphere and Radio Wave Propagation of the Russian Academy of Sciences. HSCIS product includes a personal computer with it specialized software, a dual-frequency navigation receiver and small receiving antenna. Used in the product receiver developed by NovAtel allows us to receive the signals of the navigation systems GPS/GLONASS and maintain their processing in real time. Location receiver determined autonomously: antenna position - 55.76o N, 37.94o E, coordinates ionosonde DPS-4 - 55.5o N, 37.3o E. In fact, both devices were in close proximity, which it allows for the identity conditions of observation. Both devices operate in real time. Ionosonde DPS- 4 gave the ionosphere parameters every 15 minutes, HSCIS - every minute. Information from both instruments displayed on the screen monitors, and recorded in the memory used by computers. Along with the numerical parameters on the monitor products HSCIS displayed time course of the critical frequency F2- layer of the ionosphere obtained from observations of the nearest navigation satellite. When limiting elevation observations 15o simultaneous use of navigation satellites can

Hot spots in Ar and Ne gas puff Z-pinch

International Nuclear Information System (INIS)

Krejci, A.; Krousky, E.; Renner, O.

1989-02-01

The hot spots in Ar and Ne pinch plasma were investigated. Two pinhole cameras with entrance diameter 13 to 250 μm and flat crystal spectrographs with Si and KAP crystals were used for spatially and spectrally resolved soft X-ray diagnostics. The diameters of Ar (25 to 30 μm) and Ne (40 μm) hot spots were found. From X-ray spectrum of Ar spots the following plasma parameters were determined: T e =1.0 to 1.1 keV and n e =(1.8 to 4.0)x10 27 m -3 . The validity of the Bennett equilibrium for unstable hot spots is discussed. (author). 1 fig., 11 refs

Ionospheric hot spot at high latitudes

International Nuclear Information System (INIS)

Schunk, R.W.; Sojka, J.J.

1982-01-01

A hot spot (or spots) can occur in the high-latitude ionosphere depending on the plasma convection pattern. The hot spot corresponds to a small magnetic local time-magnetic latitude region of elevated ion temperatures located near the dusk and/or dawn meridians. For asymmetric convection electric field patterns, with enhanced flow in either the dusk or dawn sector of the polar cap, a single hot spot should occur in association with the strong convection cell. However, on geomagnetically disturbed days, two strong convection cells can occur, and hence, two hot spots should exist. The hot spot should be detectable when the electric field in the strong convection cell exceeds about 40 mV m -1 . For electric fields of the order of 100 mV m -1 in the convection cell, the ion temperature in the hot spot is greatest at low altitudes, reaching 4000 0 K at 160 km, and decreases with altitude in the F-region. An ionospheric hot spot (or spots) can be expected at all seasons and for a wide range of solar cycle conditions

Suspected hypoglycaemia in out patient practice: accuracy of dried blood spot analysis.

Science.gov (United States)

Parker, D R; Bargiota, A; Cowan, F J; Corrall, R J

1997-12-01

The assay of dried blood spots on filter paper to determine blood glucose concentration has been used to detect hypoglycaemia in out patients. We assessed the accuracy of this approach in assaying blood glucose concentrations in the hypoglycaemic range. Volunteers were rendered hypoglycaemic by intravenous infusion of insulin. The glucose concentration in simultaneously taken blood samples was measured either fresh or after drying on filter paper. Twenty-four healthy young volunteers and 9 patients with insulin-dependent diabetes were studied. Plasma glucose concentrations were measured using a standard auto analyser glucose oxidase method. Whole blood taken simultaneously was placed on prepared filter paper and allowed to dry; glucose concentration was then measured using a well-established technique. A correction factor was applied to convert the glucose concentration of plasma to that of whole blood. The relationship between glucose concentrations measured by the two methods was determined by regression coefficient. In the unequivocally hypoglycaemic range (plasma dried blood spot glucose concentrations significantly correlated with standard plasma glucose concentrations (r = 0.81; P dried blood spot method had a sensitivity of 91%. In the range designated probable hypoglycaemia (plasma dried blood spot method was 100% in both ranges. Measurement of glucose concentrations in dried blood spots is specific and sensitive in the hypoglycaemic range. The present study indicates that hypoglycaemia may be excluded or confirmed respectively when levels in excess of 3.7 or below 2.8 mmol/l are found in uncorrected dried blood spot analysis.

Generation of a single hot spot by use of a deformable mirror and study of its propagation in an underdense plasma

International Nuclear Information System (INIS)

Wattellier, Benoit; Fuchs, Julien; Zou Jiping; Chanteloup, Jean-Christophe; Bandulet, Heidi; Michel, Pierre; Labaune, Christine; Depierreux, Sylvie; Kudryashov, Alexis; Aleksandrov, Alexander

2003-01-01

Adaptive optics systems offer the prospect of significantly increasing the capabilities of high-power laser focusability, which is currently limited by thermal distortions. Using novel wave-front measurement techniques that improve the stability of such systems and a downstream large-aperture deformable mirror that does not bear the usual limitations associated with precompensation, we have improved the focusability of a high-power (6x100-J, 1-ns) Nd:glass laser facility by a factor of 6. Measuring the wave front and the on-target focal spot at full power, we obtained after correction focal spots with a best Strehl ratio of 0.6. The pulse peak intensity could thus be increased to ∼2x10 16 W/cm 2 , a level beyond reach of the usual focal spot shaping techniques. We then used the near-diffraction-limited focal spots produced by this system to measure the laser-plasma coupling for a single, controlled filament of light and to underline the importance of the coupling among the numerous speckles within conventional multispeckled beams

Spread F in the Midlatitude Ionosphere According to DPS-4 Ionosonde Data

Science.gov (United States)

Panchenko, V. A.; Telegin, V. A.; Vorob'ev, V. G.; Zhbankov, G. A.; Yagodkina, O. I.; Rozhdestvenskaya, V. I.

2018-03-01

The results of studying spread F obtained from the DPS-4 ionosonde data at the observatory of the Pushkov Institute of Terrestrial Magnetism, Ionosphere, and Radio Wave Propagation (Moscow) are presented. The methodical questions that arise during the study of a spread F phenomenon in the ionosphere are considered; the current results of terrestrial observations are compared with previously published data and the results of sounding onboard an Earth-satellite vehicle. The automated algorithm for estimation of the intensity of frequency spread F, which was developed by the authors and was successfully verified via comparison of the data of the digisonde DPS-4 and the results of manual processing, is described. The algorithm makes it possible to quantify the intensity of spread F in megahertz (the dFs parameter) and in the number of points (0, 1, 2, 3). The strongest spread (3 points) is shown to be most likely around midnight, while the weakest spread (0 points) is highly likely to occur during the daytime. The diurnal distribution of a 1-2 point spread F in the winter indicates the presence of additional maxima at 0300-0600 UT and 1400-1700 UT, which may appear due to the terminator. Despite the large volume of processed data, we can not definitively state that the appearance of spread F depends on the magnetic activity indices Kp, Dst, and AL, although the values of the dFs frequency spread interval strongly increased both at day and night during the magnetic storm of March 17-22, 2015, especially in the phase of storm recovery on March 20-22.

Assessing the combined influence of TOC and black carbon in soil–air partitioning of PBDEs and DPs from the Indus River Basin, Pakistan

International Nuclear Information System (INIS)

Ali, Usman; Mahmood, Adeel; Syed, Jabir Hussain; Li, Jun; Zhang, Gan; Katsoyiannis, Athanasios; Jones, Kevin C.; Malik, Riffat Naseem

2015-01-01

Levels of polybrominated diphenyl ethers (PBDEs) and dechlorane plus (DPs) were investigated in the Indus River Basin from Pakistan. Concentrations of ∑PBDEs and ∑DPs were ranged between 0.05 and 2.38 and 0.002–0.53 ng g −1 in the surface soils while 1.43–22.1 and 0.19–7.59 pg m −3 in the passive air samples, respectively. Black carbon (f BC ) and total organic carbon (f TOC ) fractions were also measured and ranged between 0.73 and 1.75 and 0.04–0.2%, respectively. The statistical analysis revealed strong influence of f BC than f TOC on the distribution of PBDEs and DPs in the Indus River Basin soils. BDE's congener profile suggested the input of penta–bromodiphenylether (DE-71) commercial formulation in the study area. Soil–air partitioning of PBDEs were investigated by employing octanol-air partition coefficients (K OA ) and black carbon-air partition coefficients (K BC−A ). The results of both models suggested the combined influence of total organic carbon (absorption) and black carbon (adsorption) in the studied area. - Highlights: • Model based calculations of black carbon-air partition coefficients for PBDEs. • Soil and air levels of PBDEs and DPs reported first time for ecologically important sites of the Indus River Basin, Pakistan. • Both, f BC and f TOC showed combined influence on soil–air partitioning of PBDEs in the Indus River Basin, Pakistan. - BC and TOC showed combined influence on soil–air partitioning of POPs i-e., PBDEs in the Indus River Basin, Pakistan

Green Clustering Implementation Based on DPS-MOPSO

Directory of Open Access Journals (Sweden)

Yang Lu

2014-01-01

Full Text Available A green clustering implementation is proposed to be as the first method in the framework of an energy-efficient strategy for centralized enterprise high-density WLANs. Traditionally, to maintain the network coverage, all of the APs within the WLAN have to be powered on. Nevertheless, the new algorithm can power off a large proportion of APs while the coverage is maintained as the always-on counterpart. The proposed algorithm is composed of two parallel and concurrent procedures, which are the faster procedure based on K-means and the more accurate procedure based on Dynamic Population Size Multiple Objective Particle Swarm Optimization (DPS-MOPSO. To implement green clustering efficiently and accurately, dynamic population size and mutational operators are introduced as complements for the classical MOPSO. In addition to the function of AP selection, the new green clustering algorithm has another new function as the reference and guidance for AP deployment. This paper also presents simulations in scenarios modeled with ray-tracing method and FDTD technique, and the results show that about 67% up to 90% of energy consumption can be saved while the original network coverage is maintained during periods when few users are online or when the traffic load is low.

Effects of small, intense laser spots on thin films

International Nuclear Information System (INIS)

Estabrook, K.

1986-01-01

Two-dimensional hydrodynamic simulations show that small diameter laser spots burn through flat foils considerably faster than larger spots. The physical mechanisms are (1) more nearly spherical divergence from the smaller spots which allows the debris to rapidly convect radially away from the small volume of laser heated plasma and (2) a variation on thermal self-focusing in which light is refracted into this volume, increasing the local heating rate

CD and MCD spectroscopic studies of the two Dps miniferritin proteins from Bacillus anthracis: role of O2 and H2O2 substrates in reactivity of the diiron catalytic centers.

Science.gov (United States)

Schwartz, Jennifer K; Liu, Xiaofeng S; Tosha, Takehiko; Diebold, Adrienne; Theil, Elizabeth C; Solomon, Edward I

2010-12-14

DNA protection during starvation (Dps) proteins are miniferritins found in bacteria and archaea that provide protection from uncontrolled Fe(II)/O radical chemistry; thus the catalytic sites are targets for antibiotics against pathogens, such as anthrax. Ferritin protein cages synthesize ferric oxymineral from Fe(II) and O(2)/H(2)O(2), which accumulates in the large central cavity; for Dps, H(2)O(2) is the more common Fe(II) oxidant contrasting with eukaryotic maxiferritins that often prefer dioxygen. To better understand the differences in the catalytic sites of maxi- versus miniferritins, we used a combination of NIR circular dichroism (CD), magnetic circular dichroism (MCD), and variable-temperature, variable-field MCD (VTVH MCD) to study Fe(II) binding to the catalytic sites of the two Bacillus anthracis miniferritins: one in which two Fe(II) react with O(2) exclusively (Dps1) and a second in which both O(2) or H(2)O(2) can react with two Fe(II) (Dps2). Both result in the formation of iron oxybiomineral. The data show a single 5- or 6-coordinate Fe(II) in the absence of oxidant; Fe(II) binding to Dps2 is 30× more stable than Dps1; and the lower limit of K(D) for binding a second Fe(II), in the absence of oxidant, is 2-3 orders of magnitude weaker than for the binding of the single Fe(II). The data fit an equilibrium model where binding of oxidant facilitates formation of the catalytic site, in sharp contrast to eukaryotic M-ferritins where the binuclear Fe(II) centers are preformed before binding of O(2). The two different binding sequences illustrate the mechanistic range possible for catalytic sites of the family of ferritins.

Experimental investigation of cathode spots and plasma jets behavior subjected to two kinds of axial magnetic field electrodes

International Nuclear Information System (INIS)

Wang, Lijun; Deng, Jie; Zhou, Xin; Jia, Shenli; Qian, Zhonghao; Shi, Zongqian

2016-01-01

In this paper, cathode spot plasma jet (CSPJ) rotation and cathode spots behavior subjected to two kinds of large diameter axial magnetic field (AMF) electrode (cup-shaped and coil-shaped) are studied and analyzed based on experiments. The influence of gap distances on the CSPJ rotational behavior is analyzed. Experimental results show that CSPJ rotational phenomena extensively exist in the vacuum interrupters, and CSPJ rotational direction is along the direction of composite magnetic field (mainly the combination of the axial and azimuthal components). For coil-shaped and cup-shaped AMF electrodes, the rotational or inclination phenomena before the current peak value are much more significant than that after current peak value (for the same arc current), which is related to the larger ratio of azimuthal magnetic field B_t and AMF B_z (B_t/B_z). With the increase of the gap distance, the AMF strength decreases, when the arc current is kept as constant, the azimuthal magnetic field is kept invariable, the ratio between azimuthal magnetic field and AMF is increased, which results in the increase of rotational effect. For cathode spots motion, compared with cup-shaped electrode, coil-shaped electrode has the inverse AMF direction. The Robson drift direction of cathode spots of coil-shaped electrode is opposite to that of cup-shaped electrode. With the increase of gap distance, the Robson angle is decreased, which is associated with the reduced AMF strength. Erosion imprints of anode and cathode are also related to the CSPJ rotational phenomena and cathode spots behavior. The noise of arc voltage in the initial arcing stage is related to the weaker AMF.

Experimental investigation of cathode spots and plasma jets behavior subjected to two kinds of axial magnetic field electrodes

Energy Technology Data Exchange (ETDEWEB)

Wang, Lijun; Deng, Jie; Zhou, Xin; Jia, Shenli; Qian, Zhonghao; Shi, Zongqian [State Key Laboratory of Electrical Insulation and Power Equipment, Xi' an Jiaotong University, Xi' an 710049 (China)

2016-04-15

In this paper, cathode spot plasma jet (CSPJ) rotation and cathode spots behavior subjected to two kinds of large diameter axial magnetic field (AMF) electrode (cup-shaped and coil-shaped) are studied and analyzed based on experiments. The influence of gap distances on the CSPJ rotational behavior is analyzed. Experimental results show that CSPJ rotational phenomena extensively exist in the vacuum interrupters, and CSPJ rotational direction is along the direction of composite magnetic field (mainly the combination of the axial and azimuthal components). For coil-shaped and cup-shaped AMF electrodes, the rotational or inclination phenomena before the current peak value are much more significant than that after current peak value (for the same arc current), which is related to the larger ratio of azimuthal magnetic field B{sub t} and AMF B{sub z} (B{sub t}/B{sub z}). With the increase of the gap distance, the AMF strength decreases, when the arc current is kept as constant, the azimuthal magnetic field is kept invariable, the ratio between azimuthal magnetic field and AMF is increased, which results in the increase of rotational effect. For cathode spots motion, compared with cup-shaped electrode, coil-shaped electrode has the inverse AMF direction. The Robson drift direction of cathode spots of coil-shaped electrode is opposite to that of cup-shaped electrode. With the increase of gap distance, the Robson angle is decreased, which is associated with the reduced AMF strength. Erosion imprints of anode and cathode are also related to the CSPJ rotational phenomena and cathode spots behavior. The noise of arc voltage in the initial arcing stage is related to the weaker AMF.

Statistical properties of laser hot spots produced by a random phase plate

International Nuclear Information System (INIS)

Rose, H.A.; DuBois, D.F.

1993-01-01

A quantitative theory of laser hot spots, which control plasma instabilities in real laser--plasma interactions, is presented in the case of random phase plate (RPP) optics. It is shown that the probability density of intense hot spots with intensity I, P hot (I), is given by P hot (I)∼(I/I 0 2 )exp(-I/I 0 ) where I 0 is the average intensity, and that the detailed amplitude and phase variation of the laser field in the vicinity of an intense hot spot is uniquely specified by the optics and is deterministic. These hot spots may be the source of below threshold stimulated Raman scattering (SRS) and its variation with I 0 is shown to be super exponential. A brief preview of a quantitative nonlinear theory of hot-spot-induced laser filamentation is presented

Simulations of Electron Transport in Laser Hot Spots

International Nuclear Information System (INIS)

Brunner, S.; Valeo, E.

2001-01-01

Simulations of electron transport are carried out by solving the Fokker-Planck equation in the diffusive approximation. The system of a single laser hot spot, with open boundary conditions, is systematically studied by performing a scan over a wide range of the two relevant parameters: (1) Ratio of the stopping length over the width of the hot spot. (2) Relative importance of the heating through inverse Bremsstrahlung compared to the thermalization through self-collisions. As for uniform illumination [J.P. Matte et al., Plasma Phys. Controlled Fusion 30 (1988) 1665], the bulk of the velocity distribution functions (VDFs) present a super-Gaussian dependence. However, as a result of spatial transport, the tails are observed to be well represented by a Maxwellian. A similar dependence of the distributions is also found for multiple hot spot systems. For its relevance with respect to stimulated Raman scattering, the linear Landau damping of the electron plasma wave is estimated for such VD Fs. Finally, the nonlinear Fokker-Planck simulations of the single laser hot spot system are also compared to the results obtained with the linear non-local hydrodynamic approach [A.V. Brantov et al., Phys. Plasmas 5 (1998) 2742], thus providing a quantitative limit to the latter method: The hydrodynamic approach presents more than 10% inaccuracy in the presence of temperature variations of the order delta T/T greater than or equal to 1%, and similar levels of deformation of the Gaussian shape of the Maxwellian background

Estimation method for volumes of hot spots created by heavy ions

International Nuclear Information System (INIS)

Kanno, Ikuo; Kanazawa, Satoshi; Kajii, Yuji

1999-01-01

As a ratio of volumes of hot spots to cones, which have the same lengths and bottom radii with the ones of hot spots, a simple and convenient method for estimating the volumes of hot spots is described. This calculation method is useful for the study of damage producing mechanism in hot spots, and is also convenient for the estimation of the electron-hole densities in plasma columns created by heavy ions in semiconductor detectors. (author)

A comparative study of x-ray emission from laser spots in laser-heated hohlraums relative to spots on simple disk targets

International Nuclear Information System (INIS)

Ze, F.; Langer, S.H.; Kauffman, R.L.; Kilkenny, J.D.; Landen, O.; Ress, D.; Rosen, M.D.; Suter, L.J.; Wallace, R.J.; Wiedwald, J.D.

1997-01-01

In this paper we report the results of experiments that compare the x-ray emission from a laser spot in a radiation-filled hohlraum to that from a similar laser spot on a simple disk target. The studies were done using the Nova laser facility [J. D. Lindl, Phys. Plasmas 2, 3933 (1995)] in its 0.35 μm wavelength, 1 ns square pulse configuration. Focal spot intensities were 2 endash 3.5x10 15 W/cm 2 . X-ray images measured x-ray conversion in a hohlraum and from an isolated disk simultaneously. A laser spot inside a hohlraum emitted more x rays, after subtracting the background emission from the hohlraum walls, than a spot on a disk. Numerical models suggest the enhanced spot emission inside the hohlraum is due to an increase in lateral transport relative to the disk. Filamentation in the hohlraum will also increase the spot size. The models agree fairly well with the results on spot spreading but do not explain the overall increase in conversion efficiency. copyright 1997 American Institute of Physics

Calculation of the fast ion tail distribution for a spherically symmetric hot spot

Science.gov (United States)

McDevitt, C. J.; Tang, X.-Z.; Guo, Z.; Berk, H. L.

2014-10-01

The fast ion tail for a spherically symmetric hot spot is computed via the solution of a simplified Fokker-Planck collision operator. Emphasis is placed on describing the energy scaling of the fast ion distribution function in the hot spot as well as the surrounding cold plasma throughout a broad range of collisionalities and temperatures. It is found that while the fast ion tail inside the hot spot is significantly depleted, leading to a reduction of the fusion yield in this region, a surplus of fast ions is observed in the neighboring cold plasma region. The presence of this surplus of fast ions in the neighboring cold region is shown to result in a partial recovery of the fusion yield lost in the hot spot.

Calculation of the fast ion tail distribution for a spherically symmetric hot spot

Energy Technology Data Exchange (ETDEWEB)

McDevitt, C. J.; Tang, X.-Z.; Guo, Z. [Theoretical Division, Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States); Berk, H. L. [Department of Physics, University of Texas, Austin, Texas 78712 (United States)

2014-10-15

The fast ion tail for a spherically symmetric hot spot is computed via the solution of a simplified Fokker-Planck collision operator. Emphasis is placed on describing the energy scaling of the fast ion distribution function in the hot spot as well as the surrounding cold plasma throughout a broad range of collisionalities and temperatures. It is found that while the fast ion tail inside the hot spot is significantly depleted, leading to a reduction of the fusion yield in this region, a surplus of fast ions is observed in the neighboring cold plasma region. The presence of this surplus of fast ions in the neighboring cold region is shown to result in a partial recovery of the fusion yield lost in the hot spot.

Effect of the small accessary laser spots on the harmonic emission stimulated by self-focusing of a 10-micrometer scale laser spot

International Nuclear Information System (INIS)

Lin Zunqi; Zhang Huihuang; He Xingfa

1992-01-01

A novel group of experiments has shown that single 10-micrometer-radius-scale laser spot is not able to produce the 90 deg side emitted three half harmonic efficiently in a preformed laser plasmas. However, with the help of one or two accessory laser spots with the size similar to the main one, the side emitted three half can easily built up when some position and angle conditions for the accessory spots are fulfilled. The origin of these phenomena have been analyzed in terms of the two plasmon decay theory and dynamic self-focusing model

Effects of blood sample handling procedures on measurable inflammatory markers in plasma, serum and dried blood spot samples

DEFF Research Database (Denmark)

Skogstrand, K.; Thorsen, P.; Vogel, I.

2008-01-01

of whole blood samples at low temperatures and rapid isolation of plasma and serum. Effects of different handling procedures for all markers studied are given. DBSS proved to be a robust and convenient way to handle samples for immunoassay analysis of inflammatory markers in whole blood Udgivelsesdato......The interests in monitoring inflammation by immunoassay determination of blood inflammatory markers call for information on the stability of these markers in relation to the handling of blood samples. The increasing use of stored biobank samples for such ventures that may have been collected...... and stored for other purposes, justifies the study hereof. Blood samples were stored for 0, 4, 24, and 48 h at 4 degrees C, room temperature (RT), and at 35 degrees C, respectively, before they were separated into serum or plasma and frozen. Dried blood spot samples (DBSS) were stored for 0, 1, 2, 3, 7...

Plasma immune protein analysis in the orange-spotted grouper Epinephelus coioides: Evidence for altered expressions of immune factors associated with a choline-supplemented diet.

Science.gov (United States)

Shiu, Ya-Li; Chiu, Kuo-Hsun; Huynh, Truong-Giang; Liu, Ping-Chung; Liu, Chun-Hung

2017-06-01

This study aimed to unravel the regulatory roles of choline in activating immune responses and disease resistance of the orange-spotted grouper Epinephelus coioides. Fish were fed a choline-supplemented diet at 1 g kg -1 of feed for 30 days. Fish fed a fish meal basal diet without choline-supplement served as controls. At the end of the feeding trial, fish were challenged with Vibrio alginolyticus. Meanwhile, plasma proteomics of fish in each group were also evaluated by two-dimensional gel electrophoresis (2-DE), and differentially expressed proteins were identified by tandem mass spectrophotometry (MS/MS), then a Western blot analysis or real-time polymerase chain reaction was used to confirm differential expressions of immune-enhancing proteins. Results showed that choline significantly increased survival of E. coioides 48 days after being injected with V. alginolyticus. From maps of plasma proteins, a comparative analysis between the control and choline groups revealed that 111 spots matched, with 26 altered expression spots in the choline group. Of these 26 spots, 16 were upregulated and 10 downregulated. After protein identification by reverse-phase nano-high-performance liquid chromatography-electrospray ionization MS/MS analysis, eight of 26 proteins were found to be immune-related proteins, all of which were upregulated, including complement 3 (C3), alpha-2-macroglobulin-P-like isoform (A2M), fibrinogen beta chain precursor (FBG), and immunoglobulin heavy constant mu (Ighm) proteins. Expression of the A2M protein and A2M enzyme activity in plasma of fish fed choline significantly increased compared to the control group. Additionally, A2M messenger (m)RNA transcripts were also upregulated in the liver and kidneys. Significantly higher C3 expressions at both the mRNA and protein levels were detected in the liver of fish in the choline group. Moreover, FBG gene expressions in the liver and kidneys significantly increased, while Ighm increased in the

High specificity of spot urinary free metanephrines in diagnosis and prognosis of pheochromocytomas and paragangliomas by HPLC with electrochemical detection.

Science.gov (United States)

Zuo, Ming; Zhen, Qianna; Zhang, Xiaoqing; Zou, Wenbi; Yang, Xiangchun; Tian, Gang; Shi, Zhenghu; Li, Qifu; Ding, Min

2018-03-01

The metanephrines (MNs) in plasma and urine were proposed as biomarkers for the diagnosis of pheochromocytomas and paragangliomas (PPGLs). However, plasma free MNs and 24h urinary fractionated MNs were not satisfactory enough in specificity for the diagnosis of PPGLs. Moreover, the collection of 24h urine was inconvenient. This work examined the diagnostic and prognostic efficiency of free MNs in spot urine for PPGLs. We measured free MNs concentration in spot urine and plasma of 28 PPGLs patients and 155 control subjects by HPLC with electrochemical detection. Postoperative free MNs levels in spot urine and plasma of 14 PPGLs patients were also determined. Creatinine (Cr) concentration was used for the correction of urine volume. The specificity of spot urinary free MNs/Cr in the diagnosis of PPGLs was significantly higher than that of plasma free MNs [normetanephrine (NMN), 98.7% (95.4%-99.8%) vs 93.0% (87.4%-96.6%); metanephrine (MN), 93.6% (88.5%-96.9%) vs 84.5% (77.5%-90.0%)]. Meanwhile, the positive likelihood ratios for spot urinary free NMN/Cr and MN/Cr were 69.21 and 13.29, compared with 12.68 and 5.30 for plasma free NMN and MN, respectively. For the PPGLs patients underwent surgery, the plasma free MNs level appeared an abnormal elevation and yielded false-positive results for some patients. Our findings were validated in an independent cohort, resulting in the specificity of 100% for both urinary free NMN/Cr and MN/Cr, and 97.3% and 83.8% for plasma free NMN and MN, respectively. Spot urinary free MNs/Cr, superior to plasma free MNs, presented a promising biomarker for the diagnosis and prognosis of PPGLs. Copyright © 2017 Elsevier B.V. All rights reserved.

Dynamics of hot spots in the DPF-78 plasma focus from x-ray spectra and REB emission

International Nuclear Information System (INIS)

Schmidt, H.; Wang, X.X.

1995-01-01

The X-ray emission from hot spots in the plasma focus DPF-78 was investigated with the help of two X-ray quartz crystal spectrometers of the Johann type and a 4 fold magnifying X-ray pinhole camera. In the experiments the working gas was chosen to be 300 Pa deuterium with 20 Pa argon admixture. X-ray spectra in the wavelength range from 3.55 angstrom to 4.0 angstrom, including H-like and He-like Argon lines, were recorded on Kodak DEF-2 film. From the spatially resolved spectra recorded side-on, a relative spectral shift between different hot spots of the same shot was often observed. The shift could be attributed to the Doppler shift. From spectral characteristics such as intensities and FWHM of Ar resonant and intercombination lines electron densities of up to 3 x 10 27 m -3 were determined. Radial dimensions of the hot spots ranging from about 140 microm to 300 microm were found from pinhole pictures applying the penumbra method. Usually two pulses of relativistic electron beams were observed using Cherenkov detectors in a magnetic spectrometer. The energy of the first pulse, which was emitted at the time of maximum compression, was higher than that of the second pulse. The measured FWHM of the REB pulses ranges from 3 ns to about 10 ns. The characteristics of the time-integrated X-ray spectra and the time resolved REB spectra and their dependence on the composition of the filling gas are discussed

IMPLIKASI KEWENANGAN DEWAN PENGAWAS SYARIAH TERHADAP SISTEM PENGAWASAN DI BANK ACEH SYARIAH

Directory of Open Access Journals (Sweden)

Hafiizh Maulana

2014-06-01

Syariah. Untuk memperoleh jawaban tersebut, peneliti menggunakan metode deskriptif analisis. Metode pengumpulan data yang digunakan adalah penelitian lapangan melalui wawancara secara mendalam dan open kuesioner dan kepustakaan melalui dokumentasi perundang-undangan dan struktur organisasi Bank Aceh Syariah. Hasil penelitian menunjukkan bahwa pengawasan DPS berdasarkan perangkat yuridis terdiri dari undang-undang perbankan syariah No. 21 Tahun 2008 Pasal 32, Undang-Undang No. 40 Tahun 2007, Peraturan Bank Indonesia (PBI, Surat Edaran Bank Indonesia (SE BI, dan fatwa-fatwa DSN MUI. Kewenangan DPS berdasarkan struktur organisasi Bank Aceh Syariah memiliki 2 kewenangan, yaitu sebagai staf dan fungsional. Kewenangan staf berhubungan dengan posisi DPS sebagai pemberi nasihat/saran-saran dengan Dewan Komisaris Bank Aceh, sementara kewenangan fungsional berhubungan dengan Divisi Syariah Bank Aceh. Kewenangan DPS mempengaruhi kinerjanya pada aktivitas/kegiatan pengawasan, frekuensi rapat, dan sistem pelaporan. DPS Bank Aceh Syariah masih menjalankan sistem pengawasan tidak langsung (off spot melalui pengkajian, hasil laporan kegiatan, dan opini syariah secara lisan serta tertulis. Sistem pengawasan secara langsung (on spot pada struktural Bank Aceh Syariah belum dilakukan.

Morphological changes in ultrafast laser ablation plumes with varying spot size.

Science.gov (United States)

Harilal, S S; Diwakar, P K; Polek, M P; Phillips, M C

2015-06-15

We investigated the role of spot size on plume morphology during ultrafast laser ablation of metal targets. Our results show that the spatial features of fs LA plumes are strongly dependent on the focal spot size. Two-dimensional self-emission images showed that the shape of the ultrafast laser ablation plumes changes from spherical to cylindrical with an increasing spot size from 100 to 600 μm. The changes in plume morphology and internal structures are related to ion emission dynamics from the plasma, where broader angular ion distribution and faster ions are noticed for the smallest spot size used. The present results clearly show that the morphological changes in the plume with spot size are independent of laser pulse width.

Measurements of plasma mirror reflectivity and focal spot quality for tens of picosecond laser pulses

Science.gov (United States)

Forestier-Colleoni, Pierre; Williams, Jackson; Scott, Graeme; Mariscal, Dereck. A.; McGuffey, Christopher; Beg, Farhat N.; Chen, Hui; Neely, David; Ma, Tammy

2017-10-01

The Advanced Radiographic Capability (ARC) laser at the NIF (LLNL) is high-energy ( 4 kJ) with a pulse length of 30ps, and is capable of focusing to an intensity of 1018W/cm2 with a 100 μm focal spot. The ARC laser is at an intensity which can be used to produce proton beams. However, for applications such as radiography and warm dense matter creation, a higher laser intensity may be desired to generate more energetic proton beams. One possibility to increase the intensity is to decrease the focused spot size by employing a smaller f-number optic. But it is difficult to implement such an optic or to bring the final focusing parabola closer to the target within the complicated NIF chamber geometry. A proposal is to use ellipsoidal plasma mirrors (PM) for fast focusing of the ARC laser light, thereby increasing the peak intensity. There is uncertainty, however, in the survivability and reflectivity of PM at such long pulse durations. Here, we show experimental results from the Titan laser to study the reflectivity of flat PM as a function of laser pulse length. A calorimeter was used to measure the PM reflectivity. We also observed degradation of the far and near field energy distribution of the laser after the reflection by the PM for pulse-lengths beyond 10ps. Contract DE-AC52-07NA27344. Funded by the LLNL LDRD program: tracking code 17-ERD-039.

Numerical studies on the ramped density plasma lens

International Nuclear Information System (INIS)

Williams, R.L.; Katsouleas, T.

1992-01-01

We consider the so-called adiabatic plasma lens when the plasma density is ramped too quickly to be considered adiabatic. The lens length can be much shorter in such a case, but the final spot size is shown to be larger by a factor of √1+α 2 than for a slowly ramped plasma lens with the same initial and final density (where α=-β'/2 is proportional to the plasma density gradient). We find that the final spot size is the same whether or not the Courant-Snyder parameters of the beam (α and β) are matched to the lens. However, matched beams allow the plasma density to be lower while unmatched beams allow the lens to be shorter (for the same α and for the same final to initial plasma density ratio). Finally, we find that a smaller spot size can be obtained for a given lens length and density ratio by starting at smaller α and increasing α along the lens

Hot spots on the neutralizer plates of a tokamak

International Nuclear Information System (INIS)

Krasheninnikov, S.I.

1991-01-01

The formation of hot spots on the neutralizing surfaces of tokamaks may be one of the reasons for the entry of large impurity fluxes into the plasmas of TFTR and JET (the so-called carbon catastrophe or carbon bloom) with high auxiliary heating powers. At this time it is unclear whether these hot spots are caused just by nonuniformities on the neutralizer surface or whether their appearance is the result of some more general behavior, with the surface nonuniformities only showing up as seed perturbations. In this paper it is shown that hot spots can also develop on smooth surfaces of carbon neutralizer plates as a result of the contraction of a heat flux incident on the plates

Polarization of X-ray lines emitted from plasma-focus discharges; Problems of interpretation

International Nuclear Information System (INIS)

Jakubowski, L.

2002-01-01

In high current pulse discharges of the Plasma Focus (PF) type, inside the collapsing pinch column, there are formed local micro-regions of high-density and high-temperature plasma, so-called hot spots. Individual hot spots are separated in space and time. Each hot spot is characterized by its specific electron concentration and temperature, as well as by the emission of X-ray lines with different polarization. When numerous hot spots are produced it is impossible to determine local plasma parameters and to interpret the polarization effects. To eliminate this problem this study was devoted to the realization of PF-type discharges with single hot spot only. It has been achieved by a choice of the electrode configuration, which facilitated the formation of a single hot spot emitting intense X-ray lines. At the chosen experimental conditions it was possible to determine local plasma parameters and to demonstrate evident differences in the polarization of the observed X-ray lines. (author)

Polarization of x-ray lines emitted from plasma-focus discharges; Problems of interpretation

International Nuclear Information System (INIS)

Jakubowski, L.; Sadowski, M.J.; Baronova, E.O.

2003-01-01

In high current pulse discharges of the Plasma Focus (PF) type, inside the collapsing pinch column, there are formed local micro-regions of high-density and high-temperature plasma, so-called hot spots. Individual hot spots are separated in space and time. Each hot spot is characterized by its specific electron concentration and temperature, as well as by the emission of X-ray lines with different polarization. When numerous hot spots are produced it is impossible to determine local plasma parameters and to interpretate the polarization effects. To eliminate this problem this study was devoted to the realization of PF-type discharges with single hot spot only. It has been achieved by a choice of the electrode configuration, which facilitated the formation of a single hot spot emitting intense X-ray lines. At the chosen experimental conditions it was possible to determine local plasma parameters and to demonstrate evident differences in the polarization of the observed X-ray lines. (author)

Using penumbral imaging to measure micrometer size plasma hot spots in Gbar equation of state experiments on the National Ignition Facility.

Science.gov (United States)

Bachmann, B; Kritcher, A L; Benedetti, L R; Falcone, R W; Glenn, S; Hawreliak, J; Izumi, N; Kraus, D; Landen, O L; Le Pape, S; Ma, T; Pérez, F; Swift, D; Döppner, T

2014-11-01

We have developed an experimental platform for absolute equation of state measurements up to Gbar pressures on the National Ignition Facility (NIF) within the Fundamental Science Program. We use a symmetry-tuned hohlraum drive to launch a spherical shock wave into a solid CH sphere. Streaked radiography is the primary diagnostic to measure the density change at the shock front as the pressure increases towards smaller radii. At shock stagnation in the center of the capsule, we observe a short and bright x-ray self emission from high density (∼50 g/cm(3)) plasma at ∼1 keV. Here, we present results obtained with penumbral imaging which has been carried out to characterize the size of the hot spot emission. This allows extending existing NIF diagnostic capabilities for spatial resolution (currently ∼10 μm) at higher sensitivity. At peak emission we find the hot spot radius to be as small as 5.8 +/- 1 μm, corresponding to a convergence ratio of 200.

Using penumbral imaging to measure micrometer size plasma hot spots in Gbar equation of state experiments on the National Ignition Facility

International Nuclear Information System (INIS)

Bachmann, B.; Kritcher, A. L.; Benedetti, L. R.; Glenn, S.; Hawreliak, J.; Izumi, N.; Landen, O. L.; Le Pape, S.; Ma, T.; Pérez, F.; Swift, D.; Döppner, T.; Falcone, R. W.; Kraus, D.

2014-01-01

We have developed an experimental platform for absolute equation of state measurements up to Gbar pressures on the National Ignition Facility (NIF) within the Fundamental Science Program. We use a symmetry-tuned hohlraum drive to launch a spherical shock wave into a solid CH sphere. Streaked radiography is the primary diagnostic to measure the density change at the shock front as the pressure increases towards smaller radii. At shock stagnation in the center of the capsule, we observe a short and bright x-ray self emission from high density (∼50 g/cm 3 ) plasma at ∼1 keV. Here, we present results obtained with penumbral imaging which has been carried out to characterize the size of the hot spot emission. This allows extending existing NIF diagnostic capabilities for spatial resolution (currently ∼10 μm) at higher sensitivity. At peak emission we find the hot spot radius to be as small as 5.8 +/− 1 μm, corresponding to a convergence ratio of 200

Dried blood spots as a source of anti-malarial antibodies for epidemiological studies

Science.gov (United States)

Corran, Patrick H; Cook, Jackie; Lynch, Caroline; Leendertse, Heleen; Manjurano, Alphaxard; Griffin, Jamie; Cox, Jonathan; Abeku, Tarekegn; Bousema, Teun; Ghani, Azra C; Drakeley, Chris; Riley, Eleanor

2008-01-01

Background Blood spots collected onto filter paper are an established and convenient source of antibodies for serological diagnosis and epidemiological surveys. Although recommendations for the storage and analysis of small molecule analytes in blood spots exist, there are no published systematic studies of the stability of antibodies under different storage conditions. Methods Blood spots, on filter paper or glass fibre mats and containing malaria-endemic plasma, were desiccated and stored at various temperatures for different times. Eluates of these spots were assayed for antibodies against two Plasmodium falciparum antigens, MSP-119 and MSP2, and calculated titres used to fit an exponential (first order kinetic) decay model. The first order rate constants (k) for each spot storage temperature were used to fit an Arrhenius equation, in order to estimate the thermal and temporal stability of antibodies in dried blood spots. The utility of blood spots for serological assays was confirmed by comparing antibodies eluted from blood spots with the equivalent plasma values in a series of samples from North Eastern Tanzania and by using blood spot-derived antibodies to estimate malaria transmission intensity in this site and for two localities in Uganda. Results Antibodies in spots on filter paper and glass fibre paper had similar stabilities but blood was more easily absorbed onto filter papers than glass fibre, spots were more regular and spot size was more closely correlated with blood volume for filter paper spots. Desiccated spots could be stored at or below 4°C for extended periods, but were stable for only very limited periods at ambient temperature. When desiccated, recoveries of antibodies that are predominantly of IgG1 or IgG3 subclasses were similar. Recoveries of antibodies from paired samples of serum and of blood spots from Tanzania which had been suitably stored showed similar recoveries of antibodies, but spots which had been stored for extended periods

Resolving hot spot microstructure using x-ray penumbral imaging (invited)

Science.gov (United States)

Bachmann, B.; Hilsabeck, T.; Field, J.; Masters, N.; Reed, C.; Pardini, T.; Rygg, J. R.; Alexander, N.; Benedetti, L. R.; Döppner, T.; Forsman, A.; Izumi, N.; LePape, S.; Ma, T.; MacPhee, A. G.; Nagel, S.; Patel, P.; Spears, B.; Landen, O. L.

2016-11-01

We have developed and fielded x-ray penumbral imaging on the National Ignition Facility in order to enable sub-10 μm resolution imaging of stagnated plasma cores (hot spots) of spherically shock compressed spheres and shell implosion targets. By utilizing circular tungsten and tantalum apertures with diameters ranging from 20 μm to 2 mm, in combination with image plate and gated x-ray detectors as well as imaging magnifications ranging from 4 to 64, we have demonstrated high-resolution imaging of hot spot plasmas at x-ray energies above 5 keV. Here we give an overview of the experimental design criteria involved and demonstrate the most relevant influences on the reconstruction of x-ray penumbral images, as well as mitigation strategies of image degrading effects like over-exposed pixels, artifacts, and photon limited source emission. We describe experimental results showing the advantages of x-ray penumbral imaging over conventional Fraunhofer and photon limited pinhole imaging and showcase how internal hot spot microstructures can be resolved.

Resolving hot spot microstructure using x-ray penumbral imaging (invited)

Energy Technology Data Exchange (ETDEWEB)

Bachmann, B., E-mail: bachmann2@llnl.gov; Field, J.; Masters, N.; Pardini, T.; Rygg, J. R.; Benedetti, L. R.; Döppner, T.; Izumi, N.; LePape, S.; Ma, T.; MacPhee, A. G.; Nagel, S.; Patel, P.; Spears, B.; Landen, O. L. [Lawrence Livermore National Laboratory, Livermore, California 94550 (United States); Hilsabeck, T.; Reed, C.; Alexander, N.; Forsman, A. [General Atomics, San Diego, California 92186 (United States)

2016-11-15

We have developed and fielded x-ray penumbral imaging on the National Ignition Facility in order to enable sub-10 μm resolution imaging of stagnated plasma cores (hot spots) of spherically shock compressed spheres and shell implosion targets. By utilizing circular tungsten and tantalum apertures with diameters ranging from 20 μm to 2 mm, in combination with image plate and gated x-ray detectors as well as imaging magnifications ranging from 4 to 64, we have demonstrated high-resolution imaging of hot spot plasmas at x-ray energies above 5 keV. Here we give an overview of the experimental design criteria involved and demonstrate the most relevant influences on the reconstruction of x-ray penumbral images, as well as mitigation strategies of image degrading effects like over-exposed pixels, artifacts, and photon limited source emission. We describe experimental results showing the advantages of x-ray penumbral imaging over conventional Fraunhofer and photon limited pinhole imaging and showcase how internal hot spot microstructures can be resolved.

Resolving hot spot microstructure using x-ray penumbral imaging (invited).

Science.gov (United States)

Bachmann, B; Hilsabeck, T; Field, J; Masters, N; Reed, C; Pardini, T; Rygg, J R; Alexander, N; Benedetti, L R; Döppner, T; Forsman, A; Izumi, N; LePape, S; Ma, T; MacPhee, A G; Nagel, S; Patel, P; Spears, B; Landen, O L

2016-11-01

We have developed and fielded x-ray penumbral imaging on the National Ignition Facility in order to enable sub-10 μm resolution imaging of stagnated plasma cores (hot spots) of spherically shock compressed spheres and shell implosion targets. By utilizing circular tungsten and tantalum apertures with diameters ranging from 20 μm to 2 mm, in combination with image plate and gated x-ray detectors as well as imaging magnifications ranging from 4 to 64, we have demonstrated high-resolution imaging of hot spot plasmas at x-ray energies above 5 keV. Here we give an overview of the experimental design criteria involved and demonstrate the most relevant influences on the reconstruction of x-ray penumbral images, as well as mitigation strategies of image degrading effects like over-exposed pixels, artifacts, and photon limited source emission. We describe experimental results showing the advantages of x-ray penumbral imaging over conventional Fraunhofer and photon limited pinhole imaging and showcase how internal hot spot microstructures can be resolved.

Resolving hot spot microstructure using x-ray penumbral imaging (invited)

International Nuclear Information System (INIS)

Bachmann, B.; Field, J.; Masters, N.; Pardini, T.; Rygg, J. R.; Benedetti, L. R.; Döppner, T.; Izumi, N.; LePape, S.; Ma, T.; MacPhee, A. G.; Nagel, S.; Patel, P.; Spears, B.; Landen, O. L.; Hilsabeck, T.; Reed, C.; Alexander, N.; Forsman, A.

2016-01-01

We have developed and fielded x-ray penumbral imaging on the National Ignition Facility in order to enable sub-10 μm resolution imaging of stagnated plasma cores (hot spots) of spherically shock compressed spheres and shell implosion targets. By utilizing circular tungsten and tantalum apertures with diameters ranging from 20 μm to 2 mm, in combination with image plate and gated x-ray detectors as well as imaging magnifications ranging from 4 to 64, we have demonstrated high-resolution imaging of hot spot plasmas at x-ray energies above 5 keV. Here we give an overview of the experimental design criteria involved and demonstrate the most relevant influences on the reconstruction of x-ray penumbral images, as well as mitigation strategies of image degrading effects like over-exposed pixels, artifacts, and photon limited source emission. We describe experimental results showing the advantages of x-ray penumbral imaging over conventional Fraunhofer and photon limited pinhole imaging and showcase how internal hot spot microstructures can be resolved.

Dusty-Plasma Particle Accelerator

Science.gov (United States)

Foster, John E.

2005-01-01

initiation of a low-current, high-voltage cathode spot. Plasma pressure associated with the cathode spot as well as the large voltage drop at the cathode spot accelerates the charged particles toward the substrate. The ultimate kinetic energy attained by particles exiting the particle holder depends in part on the magnitude of the cathode spot sheath potential difference, which is proportional to the magnitude of the voltage pulse, and the on the electric charge on the dust. The magnitude of the voltage pulse can be controlled directly, whereas the particle s electric charge can be controlled indirectly by controlling the operating parameters of the plasma apparatus.

The design of LMJ focal spots for indirect drive experiments

International Nuclear Information System (INIS)

Le Garrec, B J; Sajer, J M

2008-01-01

LMJ is a 240 high power laser beam facility for achieving laser matter interaction experiments, high energy density science, including the demonstration of fusion ignition through Inertial Confinement. The Laser Integration Line (LIL) facility is currently a 4-beam prototype for LMJ. The intensity I 0 at the focal spot centre drives hydrodynamic and plasma instabilities and the intensity in the wings must be low to go through the laser entrance Hohlraum. A simple model has been developed to compute the LMJ focal spot. The model gives the intensity at the centre as a function of the focal spot area at 3% of the maximum

Laser spot detection based on reaction diffusion

Czech Academy of Sciences Publication Activity Database

Vázquez-Otero, Alejandro; Khikhlukha, Danila; Solano-Altamirano, J. M.; Dormido, R.; Duro, N.

2016-01-01

Roč. 16, č. 3 (2016), s. 1-11, č. článku 315. ISSN 1424-8220 R&D Projects: GA MŠk EF15_008/0000162 Grant - others:ELI Beamlines(XE) CZ.02.1.01/0.0/0.0/15_008/0000162 Institutional support: RVO:68378271 Keywords : laser spot detection * laser beam detection * reaction diffusion models * Fitzhugh-Nagumo model * reaction diffusion computation * Turing patterns Subject RIV: BL - Plasma and Gas Discharge Physics OBOR OECD: Fluids and plasma physics (including surface physics) Impact factor: 2.677, year: 2016

Influence of the number of cones on speckle patterns in the Laser MegaJoule configuration

International Nuclear Information System (INIS)

Le Cain, A.; Riazuelo, G.; Sajer, J. M.

2013-01-01

This paper investigates statistical properties of hot spots when speckle patterns are generated by the superimposition of multiple laser beams in a 2 cone and a 3 cone Laser MegaJoule configuration in the zone where all the beams overlap. Three different cases of polarizations are investigated: P polarization, S polarization and the case of Double Polarization Smoothing (DPS). It is found that the sizes of the speckles depend on the choice of the polarization and that DPS seems to be the best option in both configurations. It is shown that the longitudinal radius of the hot spots in a 2 cone configuration is bigger than in a 3 cone configuration. (authors)

Humoral immune response of the small-spotted catshark, Scyliorhinus canicula.

Science.gov (United States)

Crouch, Kathryn; Smith, Lauren E; Williams, Rebecca; Cao, Wei; Lee, Mike; Jensen, Allan; Dooley, Helen

2013-05-01

Cartilaginous fishes are the oldest group in which an adaptive immune system based on immunoglobulin-superfamily members is found. This manuscript compares humoral immune function in small-spotted catshark (Scyliorhinus canicula) with that described for spiny dogfish (Squalus acanthias), another member of the Squalomorphi superorder, and nurse shark, the model for humoral immunity in elasmobranchs and a member of the Galeomorphi superorder. Although small-spotted catshark and nurse shark are separated by over 200 million years we found that immunoglobulin isoforms are well conserved between the two species. However, the plasma protein profile of small-spotted catshark was most similar to that of spiny dogfish, with low levels of pentameric IgM, and IgNAR present as a multimer in plasma rather than a monomer. We show that an antigen-specific monomeric IgM response, with a profile similar to that described previously for nurse sharks, can be raised in small-spotted catshark. Lacking polyclonal or monoclonal antibody reagents for detecting catshark IgNAR we investigated phage-display and recombinant Fc-fusion protein expression as alternative methods to look for an antigen-specific response for this isotype. However, we could find no evidence of an antigen-specific IgNAR in the animals tested using either of these techniques. Thus, unlike nurse sharks where antigen-specific monomeric IgM and IgNAR appear together, it seems there may be a temporal or complete 'uncoupling' of these isotypes during a humoral response in the small-spotted catshark. Copyright © 2013 Elsevier Ltd. All rights reserved.

Cathodic Arcs From Fractal Spots to Energetic Condensation

CERN Document Server

Anders, Andre

2009-01-01

Emphasizes the fractal character of cathode spots, and describes strongly fluctuating plasma properties such as the presence of multiply charged ions that move with supersonic velocity. This book also deals with issues, such as arc source construction, and macroparticle removal. It is intended for scientists, practitioners, and students alike

Energy transport in laser produced plasmas

International Nuclear Information System (INIS)

Key, M.H.

1989-06-01

The study of energy transport in laser produced plasmas is of great interest both because it tests and develops understanding of several aspects of basic plasma physics and also because it is of central importance in major applications of laser produced plasmas including laser fusion, the production of intense X-ray sources, and X-ray lasers. The three sections cover thermal electrons (energy transport in one dimension, plane targets and lateral transport from a focal spot, thermal smoothing, thermal instabilities), hot electrons (preheating in one dimension, lateral transport from a focal spot) and radiation (preheating in one dimension, lateral transport and smoothing, instabilities). (author)

Non-equilibrium between ions and electrons inside hot spots from National Ignition Facility experiments

Directory of Open Access Journals (Sweden)

Zhengfeng Fan

2017-01-01

Full Text Available The non-equilibrium between ions and electrons in the hot spot can relax the ignition conditions in inertial confinement fusion [Fan et al., Phys. Plasmas 23, 010703 (2016], and obvious ion-electron non-equilibrium could be observed by our simulations of high-foot implosions when the ion-electron relaxation is enlarged by a factor of 2. On the other hand, in many shots of high-foot implosions on the National Ignition Facility, the observed X-ray enhancement factors due to ablator mixing into the hot spot are less than unity assuming electrons and ions have the same temperature [Meezan et al., Phys. Plasmas 22, 062703 (2015], which is not self-consistent because it can lead to negative ablator mixing into the hot spot. Actually, this non-consistency implies ion-electron non-equilibrium within the hot spot. From our study, we can infer that ion-electron non-equilibrium exists in high-foot implosions and the ion temperature could be ∼9% larger than the equilibrium temperature in some NIF shots.

A matching approach to communicate through the plasma sheath surrounding a hypersonic vehicle

International Nuclear Information System (INIS)

Gao, Xiaotian; Jiang, Binhao

2015-01-01

In order to overcome the communication blackout problem suffered by hypersonic vehicles, a matching approach has been proposed for the first time in this paper. It utilizes a double-positive (DPS) material layer surrounding a hypersonic vehicle antenna to match with the plasma sheath enclosing the vehicle. Analytical analysis and numerical results indicate a resonance between the matched layer and the plasma sheath will be formed to mitigate the blackout problem in some conditions. The calculated results present a perfect radiated performance of the antenna, when the match is exactly built between these two layers. The effects of the parameters of the plasma sheath have been researched by numerical methods. Based on these results, the proposed approach is easier to realize and more flexible to the varying radiated conditions in hypersonic flight comparing with other methods

Using penumbral imaging to measure micrometer size plasma hot spots in Gbar equation of state experiments on the National Ignition Facility

Energy Technology Data Exchange (ETDEWEB)

Bachmann, B., E-mail: bachmann2@llnl.gov; Kritcher, A. L.; Benedetti, L. R.; Glenn, S.; Hawreliak, J.; Izumi, N.; Landen, O. L.; Le Pape, S.; Ma, T.; Pérez, F.; Swift, D.; Döppner, T. [Lawrence Livermore National Laboratory, Livermore, California 94550 (United States); Falcone, R. W. [Department of Physics, University of California, Berkeley, California 94720 (United States); Lawrence Berkeley National Laboratory, Berkeley, California 94720 (United States); Kraus, D. [Department of Physics, University of California, Berkeley, California 94720 (United States)

2014-11-15

We have developed an experimental platform for absolute equation of state measurements up to Gbar pressures on the National Ignition Facility (NIF) within the Fundamental Science Program. We use a symmetry-tuned hohlraum drive to launch a spherical shock wave into a solid CH sphere. Streaked radiography is the primary diagnostic to measure the density change at the shock front as the pressure increases towards smaller radii. At shock stagnation in the center of the capsule, we observe a short and bright x-ray self emission from high density (∼50 g/cm{sup 3}) plasma at ∼1 keV. Here, we present results obtained with penumbral imaging which has been carried out to characterize the size of the hot spot emission. This allows extending existing NIF diagnostic capabilities for spatial resolution (currently ∼10 μm) at higher sensitivity. At peak emission we find the hot spot radius to be as small as 5.8 +/− 1 μm, corresponding to a convergence ratio of 200.

Atmospheric cold plasma jet for plant disease treatment

Science.gov (United States)

Zhang, Xianhui; Liu, Dongping; Zhou, Renwu; Song, Ying; Sun, Yue; Zhang, Qi; Niu, Jinhai; Fan, Hongyu; Yang, Si-ze

2014-01-01

This study shows that the atmospheric cold plasma jet is capable of curing the fungus-infected plant leaves and controlling the spread of infection as an attractive tool for plant disease management. The healing effect was significantly dependent on the size of the black spots infected with fungal cells and the leaf age. The leaves with the diameter of black spots of plasma-generated species passing through the microns-sized stomas in a leaf can weaken the function of the oil vacuoles and cell membrane of fungal cells, resulting in plasma-induced inactivation.

Statistical analysis of the sizes and velocities of laser hot spots of smoothed beams

International Nuclear Information System (INIS)

Garnier, J.; Videau, L.

2001-01-01

This paper presents a precise description of the characteristics of the hot spots of a partially coherent laser pulse. The average values of the sizes and velocities of the hot spots are computed, as well as the corresponding probability density functions. Applications to the speckle patterns generated by optical smoothing techniques for uniform irradiation in plasma physics are discussed

Scanning vs. single spot laser ablation (λ=213 nm) inductively coupled plasma mass spectrometry

International Nuclear Information System (INIS)

Gonzalez, Jhanis J.; Fernandez, Alberto; Mao Xianglei; Russo, Richard E.

2004-01-01

Sampling strategy is defined in this work as the interaction of a repetitively pulsed laser beam with a fixed position on a sample (single spot) or with a moving sample (scan). Analytical performance of these sampling strategies was compared by using 213 nm laser ablation ICP-MS. A geological rock (Tuff) was quantitatively analyzed based on NIST series 610-616 glass standard reference materials. Laser ablation data were compared to ICP-MS analysis of the dissolved samples. The scan strategy (50 μm/s) produced a flat, steady temporal ICP-MS response whereas the single spot strategy produced a signal that decayed with time (after 60 s). Single-spot sampling provided better accuracy and precision than the scan strategy when the first 15 s of the sampling time was eliminated from the data analysis. In addition, the single spot strategy showed less matrix dependence among the four NIST glasses

Relation between surface roughness and number of cathode spots of a low-pressure arc

International Nuclear Information System (INIS)

Sato, Atsushi; Iwao, Toru; Yumoto, Motoshige

2008-01-01

A remarkable characteristic of the cathode spot of a low-pressure arc is that it can remove an oxide layer preferentially. Recently, cathode spots of a low-pressure arc have been used for cleaning metal oxide surfaces before thermal spraying or surface modification. Nevertheless, few reports have described the cathode spot movement or the oxide removal process. This experiment was carried out using a Fe+C cathode workpiece and a cylindrical copper anode. The cathode spot movement was recorded using a high-speed video camera. The images were later analysed using plasma image processing. The workpiece surface, which was covered with a 9.67 μm thick oxide, was analysed using laser microscopy after processing. The surface roughness and the number of cathode spots showed no direct relation because the current density per cathode spot did not change according to the number of cathode spots.

Random phase plate hot spots and their effect on stimulated Brillouin backscatter and self-focusing

International Nuclear Information System (INIS)

Rose, H.A.

1995-01-01

Laser hot spots, as determined by Random Phase Plate (RPP) hot spots, control the critical value of the average intensity, I c , at which there is a rapid onset of stimulated scatter in the strongly damped convective regime of three wave parametric instabilities. For the case of stimulated Brillouin backscatter in a long scale length plasma, nascent hot spot ponderomotive self-focusing is shown to reduce the value of I c in the regime of very strongly damped acoustic waves. RPP hot spots have two, intrinsically nonlinear, thresholds for ponderomotive self-focusing. Large intensity amplifications occur in the hot spot neighborhood when the hot spot power exceeds a certain critical power, P c , which is independent of the optic's f number, F. When the second, F-dependent, hot spot power threshold is exceeded, a filament emerges from the far side of the hot spot, whose extent grows erratically in time

Effect of the small-scale auxiliary laser spots on the 3ω0/2 harmonic emission

International Nuclear Information System (INIS)

Lin, Z.; Zhang, H.; He, X.; Lin, K.; Wang, X.; Zhuang, Y.; Wang, L.; Wei, X.; Lu, Q.; Shi, A.; Dai, M.; Tian, L.; Fan, G.; Li, J.

1992-01-01

Experiments have shown that a single 10-μm-radius laser spot is not able to produce the 90 degree side-emitted 3/2 harmonic efficiently in a preformed laser plasma. However, with the help of one or two auxiliary laser spots with a size similar to that of the main spot, the side-emitted 3/2 harmonic can frequently be detected when some positional and angular conditions for the auxiliary spots are met. The origin of these phenomena has been analyzed in terms of a proposed reflected laser photon-coupling model

Stimulated Brillouin backscattering and magnetic field generation in laser-produced plasmas

International Nuclear Information System (INIS)

Bawa'aneh, M.S.

1999-01-01

This thesis is concerned with aspects of laser-plasma interactions related to fusion reactions; in particular thermoelectric magnetic field generation around a hole dug in plasma by intense laser beams, and stimulated Brillouin back scattering (SBBS) from plasmas containing hot spots. A hole, of the size of the laser focal spot, is dug in the plasma when illuminated by intense laser if the laser pressure exceeds the plasma thermal pressure. This hole is found to have steep, radial density gradients. My first concern arose from the prediction that magnetic fields might be generated around the hole-plasma interface in places where the steep density gradients overlap with the non-aligned temperature gradients. When a high-power laser beam is focused on a solid pellet, plasma is formed at the surface. In order to create conditions for thermonuclear reactions in the interior of the pellet, an effective deposition of the laser energy to thermal energy of the pellet via laser-plasma coupling is necessary. When light irradiates a plasma collective processes occur, which can either enhance or reduce the light absorption. For a better understanding of the fusion problem a knowledge of the nature of these collective processes and of the fraction of light reflected from the plasma modes is required. Local hot spots seen experimentally lead to higher gain levels of scattered light. These local temperature inhomogeneities could lead to non-equilibrium distributions, which result in a free energy leading to some interesting phenomena in plasma. In the second part of the thesis stimulated Brillouin back scattering from an ion acoustic mode in a hot spot is studied. Temperature inhomogeneities lead to an ion acoustic instability, and to higher levels of SBBS gain, which leads to lower thresholds for the same electron to ion temperature ratios. This could be the answer for the observed high levels of scattering from hot spots. (author)

Liver spots

Science.gov (United States)

... skin changes - liver spots; Senile or solar lentigines; Skin spots - aging; Age spots ... Liver spots are changes in skin color that occur in older skin. The coloring may be due to aging, exposure to the sun ...

Laser-produced dense plasma in extremely high pressure gas and its application to a plasma-bridged gap switch

International Nuclear Information System (INIS)

Yamada, J.; Okuda, A.

1989-01-01

When an extremely high pressure gas is irradiated by an intense laser light, a dense plasma produced at the focal spot moves towards the focusing lens with a high velocity. Making use of this phenomenon, a new plasma-bridged gap switch is proposed and its switching characteristics is experimentally examined. From the experiments, it is confirmed that the switching time is almost constant with the applied voltage only when the focal spot is just on the positive electrode, indicating that the bridging of gap is caused by the laser light. (author)

VIABILITY AND PLASMA MEMBRANE INTEGRITY OF THE SPOTTED BUFFALO EPIDIDYMAL SPERMATOZOA AFTER THAWING WITH THE ADDITION OF DEXTROSE INTO THE EXTENDER

Directory of Open Access Journals (Sweden)

M. RIZAL

2009-01-01

Full Text Available h e objective of this study was to obtain the viability and plasma membrane integrity of the spotted buff alo epididymal sperm after addition of dextrose into Andromed® extender. Spermatozoa that have been collected from cauda epididymis were diluted with Andromed® extender as control (K and Andromed® + 0.2% dextrose (P1 and Andromed® + 0.4% dextrose (P2 as treatments. h e results showed that the quality of epididymal spermatozoa decreased during cryopreservation process. h e percentage of motility after thawing in P1 (46% and P2 (46.67% were signifi cantly higher (P<0.05 compared to K (41% as well as the percentage of live sperm in P1 (58.8% and P2 (60% compared to K (52.2%. h e percentage of membrane integrity in P1, P2 and K were 67.4; 66.8 and 68 %, respectively. In conclusion, the addition of 0.2 and 0.4% of dextrose into Andromed® acted as an extra cellular cryoprotectant and could maintain the viability and membrane integrity of the spotted buff alo epididymal spermatozoa after thawing.

SpotADAPT

DEFF Research Database (Denmark)

Kaulakiene, Dalia; Thomsen, Christian; Pedersen, Torben Bach

2015-01-01

by Amazon Web Services (AWS). The users aiming for the spot market are presented with many instance types placed in multiple datacenters in the world, and thus it is difficult to choose the optimal deployment. In this paper, we propose the framework SpotADAPT (Spot-Aware (re-)Deployment of Analytical...... of typical analytical workloads and real spot price traces. SpotADAPT's suggested deployments are comparable to the theoretically optimal ones, and in particular, it shows good cost benefits for the budget optimization -- on average SpotADAPT is at most 0.3% more expensive than the theoretically optimal...

Powerful Radio Galaxies with Simbol-X: Lobes and Hot Spots

Science.gov (United States)

Migliori, G.; Grandi, P.; Angelini, L.; Raimondi, L.; Torresi, E.; Palumbo, G. G. C.

2009-05-01

We present here the first Simbol-X simulations of the extended components, lobes and hot spots, of the radio galaxies. We use the paradigmatic case of Pictor A to test the capabilities of Simbol-X in this field of studies. Simulations demonstrate that Simbol-X will be able not only to perform spatially resolved studies on the lobes of radio galaxies below 10 keV but also to observe, for the first time, hard X-ray emission from the hot spots. These extremely promising results show the considerable potentiality of Simbol-X in studying interaction phenomena between relativistic plasma and surrounding environment.

Powerful Radio Galaxies with Simbol-X: Lobes and Hot Spots

International Nuclear Information System (INIS)

Migliori, G.; Grandi, P.; Raimondi, L.; Torresi, E.; Angelini, L.; Palumbo, G. G. C.

2009-01-01

We present here the first Simbol-X simulations of the extended components, lobes and hot spots, of the radio galaxies. We use the paradigmatic case of Pictor A to test the capabilities of Simbol-X in this field of studies. Simulations demonstrate that Simbol-X will be able not only to perform spatially resolved studies on the lobes of radio galaxies below 10 keV but also to observe, for the first time, hard X-ray emission from the hot spots. These extremely promising results show the considerable potentiality of Simbol-X in studying interaction phenomena between relativistic plasma and surrounding environment.

Performance of the biomerieux DBS puncher and dried blood spots ...

African Journals Online (AJOL)

Introduction: The latest World Health Organization recommendations request viral load (VL) testing, if possible, for monitoring HIV-1 infections. However, the use of plasma is an obstacle to realize this test in sub-Saharan Africa. In this context, the dried blood spot (DBS) is an interesting tool for sample collections.

New photoionization lasers pumped by laser-induced plasma radiation

International Nuclear Information System (INIS)

Hube, M.; Dieckmann, M.; Beigang, R.; Welling, H.; Wellegehausen, B.

1988-01-01

Innershell photoionization of atomic gases and vapors by soft x rays from a laser-produced plasma is a potential method for making lasers at short wavelengths. Normally, in such experiments only a single plasma spot or plasma line is created for the excitation. This gives high excitation rates but only a short excitation length. At high excitation rates detrimental influences, such as amplified spontaneous emission, optical saturation, or quenching processes, may decrease or even destroy a possible inversion. Therefore, it seems to be more favorable to use a number of separated plasma spots with smaller excitation rates and larger excitation lengths. As a test, a three-plasma spot device was constructed and used in the well-known Cd-photoionization laser at 442 nm. With a 600-mJ Nd:YAH laser (pulse length, 8 ns) for plasma production, output energies up to 300 μJ have been measured, which is more than a doubling of so far obtained data. On innershell excitation, levels may be populated that allow direct lasers as in the case of Cd or that are metastable and cannot be directly coupled to lower levels. In this case modifications in the excitation process are necessary. Such modifications may be an optical pump process in the atom prior to the innershell photoionization or an optical pump process (population transfer process) after the innershell ionization, leading to Raman or anti-Stokes Raman-type laser emissions. With these techniques and the developed multiplasma spot excitation device a variety of new laser emissions in K and Cs ions have been achieved which are indicated in the level schemes

Dynamic Positioning System (DPS) Risk Analysis Using Probabilistic Risk Assessment (PRA)

Science.gov (United States)

Thigpen, Eric B.; Boyer, Roger L.; Stewart, Michael A.; Fougere, Pete

2017-01-01

The National Aeronautics and Space Administration (NASA) Safety & Mission Assurance (S&MA) directorate at the Johnson Space Center (JSC) has applied its knowledge and experience with Probabilistic Risk Assessment (PRA) to projects in industries ranging from spacecraft to nuclear power plants. PRA is a comprehensive and structured process for analyzing risk in complex engineered systems and/or processes. The PRA process enables the user to identify potential risk contributors such as, hardware and software failure, human error, and external events. Recent developments in the oil and gas industry have presented opportunities for NASA to lend their PRA expertise to both ongoing and developmental projects within the industry. This paper provides an overview of the PRA process and demonstrates how this process was applied in estimating the probability that a Mobile Offshore Drilling Unit (MODU) operating in the Gulf of Mexico and equipped with a generically configured Dynamic Positioning System (DPS) loses location and needs to initiate an emergency disconnect. The PRA described in this paper is intended to be generic such that the vessel meets the general requirements of an International Maritime Organization (IMO) Maritime Safety Committee (MSC)/Circ. 645 Class 3 dynamically positioned vessel. The results of this analysis are not intended to be applied to any specific drilling vessel, although provisions were made to allow the analysis to be configured to a specific vessel if required.

Coupling of laser energy into plasma channels

International Nuclear Information System (INIS)

Dimitrov, D. A.; Giacone, R. E.; Bruhwiler, D. L.; Busby, R.; Cary, J. R.; Geddes, C. G. R.; Esarey, E.; Leemans, W. P.

2007-01-01

Diffractive spreading of a laser pulse imposes severe limitations on the acceleration length and maximum electron energy in the laser wake field accelerator (LWFA). Optical guiding of a laser pulse via plasma channels can extend the laser-plasma interaction distance over many Rayleigh lengths. Energy efficient coupling of laser pulses into and through plasma channels is very important for optimal LWFA performance. Results from simulation parameter studies on channel guiding using the particle-in-cell (PIC) code VORPAL [C. Nieter and J. R. Cary, J. Comput. Phys. 196, 448 (2004)] are presented and discussed. The effects that density ramp length and the position of the laser pulse focus have on coupling into channels are considered. Moreover, the effect of laser energy leakage out of the channel domain and the effects of tunneling ionization of a neutral gas on the guided laser pulse are also investigated. Power spectral diagnostics were developed and used to separate pump depletion from energy leakage. The results of these simulations show that increasing the density ramp length decreases the efficiency of coupling a laser pulse to a channel and increases the energy loss when the pulse is vacuum focused at the channel entrance. Then, large spot size oscillations result in increased energy leakage. To further analyze the coupling, a differential equation is derived for the laser spot size evolution in the plasma density ramp and channel profiles are simulated. From the numerical solution of this equation, the optimal spot size and location for coupling into a plasma channel with a density ramp are determined. This result is confirmed by the PIC simulations. They show that specifying a vacuum focus location of the pulse in front of the top of the density ramp leads to an actual focus at the top of the ramp due to plasma focusing, resulting in reduced spot size oscillations. In this case, the leakage is significantly reduced and is negligibly affected by ramp length

Effects of Hot-Spot Geometry on Backscattering and Down-Scattering Neutron Spectra

Science.gov (United States)

Mohamed, Z. L.; Mannion, O. M.; Forrest, C. J.; Knauer, J. P.; Anderson, K. S.; Radha, P. B.

2017-10-01

The measured neutron spectrum produced by a fusion experiment plays a key role in inferring observable quantities. One important observable is the areal density of an implosion, which is inferred by measuring the scattering of neutrons. This project seeks to use particle-transport simulations to model the effects of hot-spot geometry on backscattering and down-scattering neutron spectra along different lines of sight. Implosions similar to those conducted at the Laboratory of Laser Energetics are modeled by neutron transport through a DT plasma and a DT ice shell using the particle transport codes MCNP and IRIS. Effects of hot-spot geometry are obtained by ``detecting'' scattered neutrons along different lines of sight. This process is repeated for various hot-spot geometries representing known shape distortions between the hot spot and the shell. This material is based upon work supported by the Department of Energy National Nuclear Security Administration under Award Number DE-NA0001944.

A method for the direct injection and analysis of small volume human blood spots and plasma extracts containing high concentrations of organic solvents using revered-phase 2D UPLC/MS.

Science.gov (United States)

Rainville, Paul D; Simeone, Jennifer L; Root, Dan S; Mallet, Claude R; Wilson, Ian D; Plumb, Robert S

2015-03-21

The emergence of micro sampling techniques holds great potential to improve pharmacokinetic data quality, reduce animal usage, and save costs in safety assessment studies. The analysis of these samples presents new challenges for bioanalytical scientists, both in terms of sample processing and analytical sensitivity. The use of two dimensional LC/MS with, at-column-dilution for the direct analysis of highly organic extracts prepared from biological fluids such as dried blood spots and plasma is demonstrated. This technique negated the need to dry down and reconstitute, or dilute samples with water/aqueous buffer solutions, prior to injection onto a reversed-phase LC system. A mixture of model drugs, including bromhexine, triprolidine, enrofloxacin, and procaine were used to test the feasibility of the method. Finally an LC/MS assay for the probe pharmaceutical rosuvastatin was developed from dried blood spots and protein-precipitated plasma. The assays showed acceptable recovery, accuracy and precision according to US FDA guidelines. The resulting analytical method showed an increase in assay sensitivity of up to forty fold as compared to conventional methods by maximizing the amount loaded onto the system and the MS response for the probe pharmaceutical rosuvastatin from small volume samples.

Bier spots

Directory of Open Access Journals (Sweden)

Ahu Yorulmaz,

2015-10-01

Full Text Available Also called as physiologic anemic macules, Bier spots are small, hypopigmented irregularly shaped macules against a background of diffuse erythema, which creates an appearance of speckled vascular mottling of the skin. Bier spots most commonly appear on distal portions of the limbs though there are case reports describing diffuse involvement, which also affect trunk and mucous membranes of the patient. Although the exact pathophysiological mechanisms underlying Bier spots still need to be elucidated, Bier spots have been suggested to be a vascular anomaly caused by vasoconstriction of small vessels. In addition, several diseases have been proposed to be associated with Bier spots, including scleroderma renal crisis, cryoglobulinemia, Peutz-Jeghers syndrome, alopecia areata and hypoplasia of the aorta, although it has not been shown whether these associations are casual or coincidental. The clinical presentation of Bier spots is quite typical. These tiny whitish macules easily become prominent when the affected limb is placed in a dependent position and fade away when the limb is raised. Here we report a case of Bier spots in a 32-year-old male patient with characteristical clinical manifestations.

Validation of the Use of Dried Blood Spot (DBS) Method to Assess Vitamin A Status

Science.gov (United States)

Fallah, Elham; Peighambardoust, Seyed Hadi

2012-01-01

Background: Vitamin A deficiency is an important dietary deficiency in the world. Thus, the ne¬cessity of screening for deficient populations is obvious. This paper introduces a fast, cheap and relatively reliable method called “dried blood spot” (DBS) method in screening the deficient populations. The validity of this method for retinol measurement was investigated. Method: The “precision” and “agreement” criteria of the DBS method were assessed. The preci¬sion was calculated and compared with those of plasma using F-test. The agreement was eva¬luated using Bland-Altman plot. Results: The imprecision of retinol measurements in dried spots was not significantly different from those of the control (plasma). A good correlation coefficient (r2=0.78) was obtained for dried spots’ retinol measurements versus plasma’s retinol analysis (P dried spots was stable for 90 days. Overall, the DBS method provided a precise measurement of retinol, showing results that were comparable with the measurement of retinol in plasma. PMID:24688932

Comparison of the quantification of acetaminophen in plasma, cerebrospinal fluid and dried blood spots using high-performance liquid chromatography-tandem mass spectrometry.

Science.gov (United States)

Taylor, Rachel R; Hoffman, Keith L; Schniedewind, Björn; Clavijo, Claudia; Galinkin, Jeffrey L; Christians, Uwe

2013-09-01

Acetaminophen (paracetamol, N-(4-hydroxyphenyl) acetamide) is one of the most commonly prescribed drugs for the management of pain in children. Quantification of acetaminophen in pre-term and term neonates and small children requires the availability of highly sensitive assays in small volume blood samples. We developed and validated an LC-MS/MS assay for the quantification of acetaminophen in human plasma, cerebro-spinal fluid (CSF) and dried blood spots (DBS). Reconstitution in water (DBS only) and addition of a protein precipitation solution containing the deuterated internal standard were the only manual steps. Extracted samples were analyzed on a Kinetex 2.6 μm PFP column using an acetonitrile/formic acid gradient. The analytes were detected in the positive multiple reaction mode. Alternatively, DBS were automatically processed using direct desorption in a sample card and preparation (SCAP) robotic autosampler in combination with online extraction. The range of reliable response in plasma and CSF was 3.05-20,000 ng/ml (r(2)>0.99) and 27.4-20,000 ng/ml (r(2)>0.99) for DBS (manual extraction and automated direct desorption). Inter-day accuracy was always within 85-115% and inter-day precision for plasma, CSF and manually extracted DBS were less than 15%. Deming regression analysis comparing 167 matching pairs of plasma and DBS samples showed a correlation coefficient of 0.98. Bland Altman analysis indicated a 26.6% positive bias in DBS, most likely reflecting the blood: plasma distribution ratio of acetaminophen. DBS are a valid matrix for acetaminophen pharmacokinetic studies. Copyright © 2013 Elsevier B.V. All rights reserved.

Particle-in-cell studies of laser-driven hot spots and a statistical model for mesoscopic properties of Raman backscatter

International Nuclear Information System (INIS)

Albright, B.J.; Yin, L.; Bowers, K.J.; Kline, J.L.; Montgomery, D.S.; Fernandez, J.C.; Daughton, W.

2006-01-01

The authors use explicit particle-in-cell simulations to model stimulated scattering processes in media with both solitary and multiple laser hot spots. These simulations indicate coupling among hot spots, whereby scattered light, plasma waves, and hot electrons generated in one laser hot spot may propagate to neighboring hot spots, which can be destabilized to enhanced backscatter. A nonlinear statistical model of a stochastic beam exhibiting this coupled behavior is described here. Calibration of the model using particle-in-cell simulations is performed, and a threshold is derived for 'detonation' of the beam to high reflectivity. (authors)

SU-E-T-510: Interplay Between Spots Sizes, Spot / Line Spacing and Motion in Spot Scanning Proton Therapy

International Nuclear Information System (INIS)

Lee, TK

2015-01-01

Purpose In proton beam configuration for spot scanning proton therapy (SSPT), one can define the spacing between spots and lines of scanning as a ratio of given spot size. If the spacing increases, the number of spots decreases which can potentially decrease scan time, and so can whole treatment time, and vice versa. However, if the spacing is too large, the uniformity of scanned field decreases. Also, the field uniformity can be affected by motion during SSPT beam delivery. In the present study, the interplay between spot/ line spacing and motion is investigated. Methods We used four Gaussian-shape spot sizes with 0.5cm, 1.0cm, 1.5cm, and 2.0cm FWHM, three spot/line spacing that creates uniform field profile which are 1/3*FWHM, σ/3*FWHM and 2/3*FWHM, and three random motion amplitudes within, +/−0.3mm, +/−0.5mm, and +/−1.0mm. We planned with 2Gy uniform single layer of 10×10cm2 and 20×20cm2 fields. Then, mean dose within 80% area of given field size, contrubuting MU per each spot assuming 1cGy/MU calibration for all spot sizes, number of spots and uniformity were calculated. Results The plans with spot/line spacing equal to or smaller than 2/3*FWHM without motion create ∼100% uniformity. However, it was found that the uniformity decreases with increased spacing, and it is more pronounced with smaller spot sizes, but is not affected by scanned field sizes. Conclusion It was found that the motion during proton beam delivery can alter the dose uniformity and the amount of alteration changes with spot size which changes with energy and spot/line spacing. Currently, robust evaluation in TPS (e.g. Eclipse system) performs range uncertainty evaluation using isocenter shift and CT calibration error. Based on presented study, it is recommended to add interplay effect evaluation to robust evaluation process. For future study, the additional interplay between the energy layers and motion is expected to present volumetric effect

Preliminary study on plasma proteins in pregnant and non-pregnant female dogs.

Science.gov (United States)

Szczubiał, Marek; Wawrzykowski, Jacek; Dąbrowski, Roman; Krawczyk, Magdalena; Kankofer, Marta

2017-07-15

In this study, we used a combined approach based on 2-dimensional electrophoresis (2-DE), difference in gel electrophoresis (DIGE), and mass spectrometry (MS) to identify the plasma protein composition in pregnant female dogs and compared it with non-pregnant female dogs. We used the plasma samples obtained from four female dogs during I, II, and III thirds of pregnancy, three days after parturition, as well as from four non-pregnant female dogs in diestrus phase. Analysis of 2-DE gel image exhibited of 249 protein spots. The intensity of staining of 35 spots differed significantly (P dogs. We used matrix-assisted laser desorption/ionization-time of flight-mass spectrometry (MALDI TOF MS) to identify 47 spots corresponding to 52 different proteins. Five identified protein spots, including zinc finger BED domain-containing protein 5, hemoglobin subunit beta-2, integrator complex subunit 7, apolipoprotein A-I, and glutamyl aminopeptidase were differentially presented in the plasma of pregnant and non-pregnant female dogs. To the best of our knowledge, this is the first report on the plasma protein profile of pregnant and non-pregnant female dogs. In this study, we identified proteins that have not been previously identified in dogs. Our findings showed that numerous protein spots were differentially presented in the plasma of female dogs during normal pregnancy. Although we identified only a limited number of differentially presented proteins, our study demonstrated that the plasma protein profile changed during pregnancy in female dogs, which suggests its importance in maintaining pregnancy. Further studies are necessary to define complete plasma protein profile of pregnant female dogs and to identify all proteins that are differentially presented in the pregnant animals compared with the non-pregnant ones. In addition, studies are warranted to explain the role of those proteins in maintaining the pregnancy and their usefulness in detection of early pregnancy

Plasma androgen concentrations in initial samples from spotted ...

African Journals Online (AJOL)

1990-01-31

Jan 31, 1990 ... initial samples, the immobilization stress response and the response to exogenous GnRH administration, for ... the sex-specific differences in plasma androgens is confounded by other variables such as the reproductive.

Plasma and breast milk pharmacokinetics of emtricitabine, tenofovir and lamivudine using dried blood and breast milk spots in nursing African mother-infant pairs.

Science.gov (United States)

Waitt, Catriona; Olagunju, Adeniyi; Nakalema, Shadia; Kyohaire, Isabella; Owen, Andrew; Lamorde, Mohammed; Khoo, Saye

2018-04-01

Breast milk transfer of first-line ART from mother to infant is not fully understood. To determine the concentrations of lamivudine, emtricitabine and tenofovir in maternal blood, breast milk and infant blood from breastfeeding mother-infant pairs. Intensive pharmacokinetic sampling of maternal dried blood spots (DBS), dried breast milk spots (DBMS) and infant DBS from 30 Ugandan and 29 Nigerian mothers receiving first-line ART and their infants was conducted. DBS and DBMS were collected pre-dose and at 5-6 timepoints up to 12 h following observed dosing. Infant DBS were sampled twice during this period. Lamivudine, emtricitabine and tenofovir were quantified using LC-MS/MS, with non-compartmental analysis to calculate key pharmacokinetic parameters. Peak concentrations in breast milk from women taking lamivudine and emtricitabine occurred later than in plasma (4-8 h compared with 2 h for lamivudine and 2-4 h for emtricitabine). Consequently, the milk-to-plasma (M:P) ratio of lamivudine taken once daily was 0.95 (0.82-1.15) for AUC0-12, whereas for AUC12-20 this was 3.04 (2.87-4.16). Lamivudine was detectable in 36% (14/39) of infants [median 17.7 (16.3-22.7) ng/mL]. For 200 mg of emtricitabine once daily, the median M:P ratio was 3.01 (2.06-3.38). Three infants (19%) had measurable emtricitabine [median 18.5 (17.6-20.8) ng/mL]. For 300 mg of tenofovir once daily, the median M:P ratio was 0.015 (0-0.03) and no infant had measurable tenofovir concentrations. Emtricitabine and lamivudine accumulate in breast milk and were detected in breastfeeding infants. In contrast, tenofovir penetrates the breast milk to a small degree, but is undetectable in breastfeeding infants.

Transitional–turbulent spots and turbulent–turbulent spots in boundary layers

Science.gov (United States)

Wu, Xiaohua; Moin, Parviz; Wallace, James M.; Skarda, Jinhie; Lozano-Durán, Adrián; Hickey, Jean-Pierre

2017-01-01

Two observations drawn from a thoroughly validated direct numerical simulation of the canonical spatially developing, zero-pressure gradient, smooth, flat-plate boundary layer are presented here. The first is that, for bypass transition in the narrow sense defined herein, we found that the transitional–turbulent spot inception mechanism is analogous to the secondary instability of boundary-layer natural transition, namely a spanwise vortex filament becomes a Λ vortex and then, a hairpin packet. Long streak meandering does occur but usually when a streak is infected by a nearby existing transitional–turbulent spot. Streak waviness and breakdown are, therefore, not the mechanisms for the inception of transitional–turbulent spots found here. Rather, they only facilitate the growth and spreading of existing transitional–turbulent spots. The second observation is the discovery, in the inner layer of the developed turbulent boundary layer, of what we call turbulent–turbulent spots. These turbulent–turbulent spots are dense concentrations of small-scale vortices with high swirling strength originating from hairpin packets. Although structurally quite similar to the transitional–turbulent spots, these turbulent–turbulent spots are generated locally in the fully turbulent environment, and they are persistent with a systematic variation of detection threshold level. They exert indentation, segmentation, and termination on the viscous sublayer streaks, and they coincide with local concentrations of high levels of Reynolds shear stress, enstrophy, and temperature fluctuations. The sublayer streaks seem to be passive and are often simply the rims of the indentation pockets arising from the turbulent–turbulent spots. PMID:28630304

Transitional-turbulent spots and turbulent-turbulent spots in boundary layers.

Science.gov (United States)

Wu, Xiaohua; Moin, Parviz; Wallace, James M; Skarda, Jinhie; Lozano-Durán, Adrián; Hickey, Jean-Pierre

2017-07-03

Two observations drawn from a thoroughly validated direct numerical simulation of the canonical spatially developing, zero-pressure gradient, smooth, flat-plate boundary layer are presented here. The first is that, for bypass transition in the narrow sense defined herein, we found that the transitional-turbulent spot inception mechanism is analogous to the secondary instability of boundary-layer natural transition, namely a spanwise vortex filament becomes a [Formula: see text] vortex and then, a hairpin packet. Long streak meandering does occur but usually when a streak is infected by a nearby existing transitional-turbulent spot. Streak waviness and breakdown are, therefore, not the mechanisms for the inception of transitional-turbulent spots found here. Rather, they only facilitate the growth and spreading of existing transitional-turbulent spots. The second observation is the discovery, in the inner layer of the developed turbulent boundary layer, of what we call turbulent-turbulent spots. These turbulent-turbulent spots are dense concentrations of small-scale vortices with high swirling strength originating from hairpin packets. Although structurally quite similar to the transitional-turbulent spots, these turbulent-turbulent spots are generated locally in the fully turbulent environment, and they are persistent with a systematic variation of detection threshold level. They exert indentation, segmentation, and termination on the viscous sublayer streaks, and they coincide with local concentrations of high levels of Reynolds shear stress, enstrophy, and temperature fluctuations. The sublayer streaks seem to be passive and are often simply the rims of the indentation pockets arising from the turbulent-turbulent spots.

Investigation of arcing on fiber-formed nanostructured tungsten by pulsed plasma during steady state plasma irradiation

Energy Technology Data Exchange (ETDEWEB)

Yajima, M., E-mail: yajima.miyuki@LHD.nifs.ac.jp [National Institute for Fusion Science, 322-6 Oroshi-cho, Toki, 509-5292 Japan (Japan); Ohno, N. [Graduate School of Engineering, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8603 (Japan); Kajita, S. [EcoTopia Science Institute, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8603 (Japan); De Temmerman, G. [ITER Organization, Route de Vinon sur Verdon, CS 90 046-13067 St Paul Lez Durance Cedex (France); Bystrov, K.; Bardin, S.; Morgan, T.W. [FOM Institute DIFFER, Dutch Institute for Fundamental Energy Research, Partner in the Trilateral Euregio Cluster, 5612 AJ Eindhoven (Netherlands); Masuzaki, S. [National Institute for Fusion Science, 322-6 Oroshi-cho, Toki, 509-5292 Japan (Japan)

2016-11-15

Arcing on fiber-formed nanostructured tungsten samples during ELM-like pulses was investigated using the superimposition of high power pulsed plasma on a steady state plasma with hydrogen gas in the linear plasma device Pilot-PSI. The ignition of arcing was observed when the floating potential of the samples was less than −75 V with sufficient heat flux. The surface observation showed that the arc spots were not in the center, but in the peripheral area of the plasma column. Considering the plasma potential profile in the Pilot-PSI, the arcing occurred at the position where the heat flux and the sheath potential drop are sufficiently large.

Vacuum arc anode plasma. I. Spectroscopic investigation

International Nuclear Information System (INIS)

Bacon, F.M.

1975-01-01

A spectroscopic investigation was made of the anode plasma of a pulsed vacuum arc with an aluminum anode and a molybdenum cathode. The arc was triggered by a third trigger electrode and was driven by a 150-A 10-μs current pulse. The average current density at the anode was sufficiently high that anode spots were formed; these spots are believed to be the source of the aluminum in the plasma investigated in this experiment. By simultaneously measuring spectral emission lines of Al I, Al II, and Al III, the plasma electron temperature was shown to decrease sequentially through the norm temperatures of Al III, Al II, and Al I as the arc was extinguished. The Boltzmann distribution temperature T/subD/ of four Al III excited levels was shown to be kT/subD//e=2.0plus-or-minus0.5 V, and the peak Al III 4D excited state density was shown to be about 5times10 17 m -3 . These data suggest a non-local-thermodynamic-equilibrium (non-LTE) model of the anode plasma when compared with the Al 3+ production in the plasma. The plasma was theoretically shown to be optically thin to the observed Al III spectral lines

Spotted inflation

International Nuclear Information System (INIS)

Matsuda, Tomohiro

2010-01-01

We describe new scenarios for generating curvature perturbations when inflaton (curvaton) has significant interactions. We consider a ''spot'', which arises from interactions associated with an enhanced symmetric point (ESP) on the trajectory. Our first example uses the spot to induce a gap in the field equation. We observe that the gap in the field equation may cause generation of curvature perturbation if it does not appear simultaneous in space. The mechanism is similar to the scenario of inhomogeneous phase transition. Then we observe that the spot interactions may initiate warm inflation in the cold Universe. Creation of cosmological perturbation is discussed in relation to the inflaton dynamics and the modulation associated with the spot interactions

The effect of laser spot shapes on polar-direct-drive implosions on the National Ignition Facility

Energy Technology Data Exchange (ETDEWEB)

Weilacher, F.; Radha, P. B., E-mail: rbah@lle.rochester.edu; Collins, T. J. B.; Marozas, J. A. [Laboratory for Laser Energetics, University of Rochester, 250 East River Road, Rochester, New York 14623 (United States)

2015-03-15

Ongoing polar-direct-drive (PDD) implosions on the National Ignition Facility (NIF) [J. D. Lindl and E. I. Moses, Phys. Plasmas 18, 050901 (2011)] use existing NIF hardware, including indirect-drive phase plates. This limits the performance achievable in these implosions. Spot shapes are identified that significantly improve the uniformity of PDD NIF implosions; outer surface deviation is reduced by a factor of 7 at the end of the laser pulse and hot-spot distortion is reduced by a factor of 2 when the shell has converged by a factor of ∼10. As a result, the neutron yield increases by approximately a factor of 2. This set of laser spot shapes is a combination of circular and elliptical spots, along with elliptical spot shapes modulated by an additional higher-intensity ellipse offset from the center of the beam. This combination is motivated in this paper. It is also found that this improved implosion uniformity is obtained independent of the heat conduction model. This work indicates that significant improvement in performance can be obtained robustly with the proposed spot shapes.

The effect of laser spot shapes on polar-direct-drive implosions on the National Ignition Facility

International Nuclear Information System (INIS)

Weilacher, F.; Radha, P. B.; Collins, T. J. B.; Marozas, J. A.

2015-01-01

Ongoing polar-direct-drive (PDD) implosions on the National Ignition Facility (NIF) [J. D. Lindl and E. I. Moses, Phys. Plasmas 18, 050901 (2011)] use existing NIF hardware, including indirect-drive phase plates. This limits the performance achievable in these implosions. Spot shapes are identified that significantly improve the uniformity of PDD NIF implosions; outer surface deviation is reduced by a factor of 7 at the end of the laser pulse and hot-spot distortion is reduced by a factor of 2 when the shell has converged by a factor of ∼10. As a result, the neutron yield increases by approximately a factor of 2. This set of laser spot shapes is a combination of circular and elliptical spots, along with elliptical spot shapes modulated by an additional higher-intensity ellipse offset from the center of the beam. This combination is motivated in this paper. It is also found that this improved implosion uniformity is obtained independent of the heat conduction model. This work indicates that significant improvement in performance can be obtained robustly with the proposed spot shapes

Spot Weight Adaptation for Moving Target in Spot Scanning Proton Therapy.

Science.gov (United States)

Morel, Paul; Wu, Xiaodong; Blin, Guillaume; Vialette, Stéphane; Flynn, Ryan; Hyer, Daniel; Wang, Dongxu

2015-01-01

This study describes a real-time spot weight adaptation method in spot-scanning proton therapy for moving target or moving patient, so that the resultant dose distribution closely matches the planned dose distribution. The method proposed in this study adapts the weight (MU) of the delivering pencil beam to that of the target spot; it will actually hit during patient/target motion. The target spot that a certain delivering pencil beam may hit relies on patient monitoring and/or motion modeling using four-dimensional (4D) CT. After the adapted delivery, the required total weight [Monitor Unit (MU)] for this target spot is then subtracted from the planned value. With continuous patient motion and continuous spot scanning, the planned doses to all target spots will eventually be all fulfilled. In a proof-of-principle test, a lung case was presented with realistic temporal and motion parameters; the resultant dose distribution using spot weight adaptation was compared to that without using this method. The impact of the real-time patient/target position tracking or prediction was also investigated. For moderate motion (i.e., mean amplitude 0.5 cm), D95% to the planning target volume (PTV) was only 81.5% of the prescription (RX) dose; with spot weight adaptation PTV D95% achieves 97.7% RX. For large motion amplitude (i.e., 1.5 cm), without spot weight adaptation PTV D95% is only 42.9% of RX; with spot weight adaptation, PTV D95% achieves 97.7% RX. Larger errors in patient/target position tracking or prediction led to worse final target coverage; an error of 3 mm or smaller in patient/target position tracking is preferred. The proposed spot weight adaptation method was able to deliver the planned dose distribution and maintain target coverage when patient motion was involved. The successful implementation of this method would rely on accurate monitoring or prediction of patient/target motion.

Spot Weight Adaptation for Moving Target in Spot Scanning Proton Therapy

Directory of Open Access Journals (Sweden)

Paul eMorel

2015-05-01

Full Text Available Purpose: This study describes a real-time spot weight adaptation method in spot-scanning proton therapy for moving target or moving patient, so that the resultant dose distribution closely matches the planned dose distribution. Materials and Methods: The method proposed in this study adapts the weight (MU of the delivering pencil beam to that of the target spot it will actually hit during patient/target motion. The target spot a certain delivering pencil beam may hit relies on patient monitoring and/or motion modeling using four-dimensional (4D CT. After the adapted delivery, the required total weight (MU for this target spot is then subtracted from the planned value. With continuous patient motion and continuous spot scanning, the planned doses to all target spots will eventually be all fulfilled. In a proof-of-principle test, a lung case was presented with realistic temporal and motion parameters; the resultant dose distribution using spot weight adaptation was compared to that without using this method. The impact of the real-time patient/target position tracking or prediction was also investigated.Results: For moderate motion (i.e., mean amplitude 0.5 cm, D95% to the planning target volume (PTV was only 81.5% of the prescription (RX dose; with spot weight adaptation PTV D95% achieves 97.7%RX. For large motion amplitude (i.e., 1.5 cm, without spot weight adaptation PTV D95% is only 42.9% of RX; with spot weight adaptation, PTV D95% achieves 97.7%RX. Larger errors in patient/target position tracking or prediction led to worse final target coverage; an error of 3mm or smaller in patient/target position tracking is preferred. Conclusion: The proposed spot weight adaptation method was able to deliver the planned dose distribution and maintain target coverage when patient motion was involved. The successful implementation of this method would rely on accurate monitoring or prediction of patient/target motion.

Modeling Laser and e-Beam Generated Plasma-Plume Experiments Using LASNEX

CERN Document Server

Ho, D

1999-01-01

The hydrodynamics code LASNEX is used to model the laser and e-beam generated plasma-plume experiments. The laser used has a wavelength of 1 (micro)m and the FWHM spot size is 1 mm. The total laser energy is 160 mJ. The simulation shows that the plume expands at a velocity of about 6 cm/(micro)s. The e-beam generated from the Experimental Test Accelerator (ETA) has 5.5 MeV and FWHM spot size ranges from 2 to 3.3 mm. From the simulations, the plasma plume expansion velocity ranges from about 3 to 6 mm/(micro)s and the velocity increases with decreasing spot size. All the simulation results reported here are in close agreement with experimental data.

Propagation of an intense laser beam in a tapered plasma channel

International Nuclear Information System (INIS)

Jha, Pallavi; Singh, Ram Gopal; Upadhyaya, Ajay K.; Mishra, Rohit K.

2008-01-01

Propagation characteristics and modulation instability of an intense laser beam propagating in an axially tapered plasma channel, having a parabolic radial density profile, are studied. Using the source-dependent expansion technique, the evolution equation for the laser spot is set up and conditions for propagation of the laser beam with a constant spot size (matched beam) are obtained. Further, the dispersion relation and growth rate of modulation instability of the laser pulse as it propagates through linearly and quadratically tapered plasma channels, have been obtained

Bier spots

OpenAIRE

Ahu Yorulmaz,; Seray Kulcu Cakmak; Esra Ar?; Ferda Artuz

2015-01-01

Also called as physiologic anemic macules, Bier spots are small, hypopigmented irregularly shaped macules against a background of diffuse erythema, which creates an appearance of speckled vascular mottling of the skin. Bier spots most commonly appear on distal portions of the limbs though there are case reports describing diffuse involvement, which also affect trunk and mucous membranes of the patient. Although the exact pathophysiological mechanisms underlying Bier spots still need to be elu...

Beam and hot spot formation in a low impedance driven vacuum spark

International Nuclear Information System (INIS)

Chuaqui, H.; Favre, M.; Soto, L.; Wyndham, E.

1990-01-01

Observations of a vacuum spark discharge plasma when driven by a 1.5 ω, 120 ns switched coaxial line at 60 kV open circuit voltage are made. A comparison of behaviour is made when a Nd: YAG laser over a range of energies is focussed either onto the anode or onto the cathode surface. A significantly different behaviour is seen if the line gap is shorted out allowing the sinusoidal voltage from the Marx to be applied to the electrodes. Hot spot formation with associated anode plasma are seen in this last case. (Author)

Use of Dried Blood Spots to Elucidate Full-Length Transmitted/Founder HIV-1 Genomes

Directory of Open Access Journals (Sweden)

Jesus F. Salazar-Gonzalez

2016-07-01

Full Text Available Background: Identification of HIV-1 genomes responsible for establishing clinical infection in newly infected individuals is fundamental to prevention and pathogenesis research. Processing, storage, and transportation of the clinical samples required to perform these virologic assays in resource-limited settings requires challenging venipuncture and cold chain logistics. Here, we validate the use of dried-blood spots (DBS as a simple and convenient alternative to collecting and storing frozen plasma. Methods: We performed parallel nucleic acid extraction, single genome amplification (SGA, next generation sequencing (NGS, and phylogenetic analyses on plasma and DBS. Results: We demonstrated the capacity to extract viral RNA from DBS and perform SGA to infer the complete nucleotide sequence of the transmitted/founder (TF HIV-1 envelope gene and full-length genome in two acutely infected individuals. Using both SGA and NGS methodologies, we showed that sequences generated from DBS and plasma display comparable phylogenetic patterns in both acute and chronic infection. SGA was successful on samples with a range of plasma viremia, including samples as low as 1,700 copies/ml and an estimated ~50 viral copies per blood spot. Further, we demonstrated reproducible efficiency in gp160 env sequencing in DBS stored at ambient temperature for up to three weeks or at -20ºC for up to five months. Conclusions: These findings support the use of DBS as a practical and cost-effective alternative to frozen plasma for clinical trials and translational research conducted in resource-limited settings.

Effect of vacuum arc cathode spot distribution on breaking capacity of the arc-extinguishing chamber

Science.gov (United States)

Ding, Can; Yuan, Zhao; He, Junjia

2017-10-01

A DC circuit breaker performs a key function in breaking an intermediate-frequency (IF) current since breaking a pure IF current is equivalent to breaking a very small DC with a reverse IF current. In this study, it is found that cathode spots show a ring-shaped distribution at 2000 Hz. An arc with an uneven distribution of cathode spots has been simulated. The simulation results show that the distribution of cathode spots significantly affect the microparameter distribution of arc plasma. The current distribution on the anode side differs from that on the cathode side under the total radial electric field. Specifically, the anode current distribution is both uneven and concentrated. The applied axial magnetic field, which cannot reduce the concentrated anode current distribution effectively, might increase the concentration of the anode current. Finally, the uneven distribution of cathode spots reduces the breaking capacity of the arc-extinguishing chamber.

Spot weld arrangement effects on the fatigue behavior of multi-spot welded joints

International Nuclear Information System (INIS)

Hassanifard, Soran; Zehsaz, Mohammad; Esmaeili, Firooz

2011-01-01

In the present study, the effects of spot weld arrangements in multi-spot welded joints on the fatigue behavior of the joints are studied. Three different four-spot welded joints are considered: one-row four-spot parallel to the loading direction, one-row four-spot perpendicular to the loading direction and two-row four-spot weld specimens. The experimental fatigue test results reveal that the differences between the fatigue lives of three spot welded types in the low cycle regime are more considerable than those in the high cycle regime. However, all kinds of spot weld specimens have similar fatigue strength when approaching a million cycles. A non-linear finite element analysis is performed to obtain the relative stress gradients, effective distances and notch strength reduction factors based on the volumetric approach. The work here shows that the volumetric approach does a very good job in predicting the fatigue life of the multi-spot welded joints

A novel approach for quantitation of glucosylceramide in human dried blood spot using LC-MS/MS.

Science.gov (United States)

Ji, Allena Ji; Wang, Haixing; Ziso-Qejvanaj, Enida; Zheng, Kefei; Chung, Lee Lee; Foley, Timothy; Chuang, Wei-Lien; Richards, Susan; Sung, Crystal

2015-01-01

Glucosylceramide, an efficacy biomarker for Gaucher Type 1 disease, exhibits poor solubility in polar solvents and whole blood which makes it difficult to prepare a homogenous blood standard. We developed a novel method using standard addition approach by spiking a small volume of analyte solution on the surface of prespotted dried blood spot. The whole spots were punched out for subsequent extraction and LC-MS/MS analysis. The assay performance met all validation acceptance criteria. Glucosylceramide concentrations in 50 paired plasma and dry blood spot samples obtained from Gaucher Type 1 patients were tested and the results demonstrated the feasibility of using the DBS method for clinical biomarker monitoring. The new approach greatly improves assay precision and accuracy.

Energy is not Coffee. An assessment of blind spots on energy spot-markets

International Nuclear Information System (INIS)

Jepma, C.J.; Spijker, E.; Van der Gaast, W.; De Jong, F.; Overmars, P.

2006-01-01

This study was to be the first in a series of studies on the title subject. It specifically focuses on the differences and similarities with a number of other spot-markets and aims to frame the energy spot markets and their potential development into a broader perspective. Main conclusion is that energy spot-markets differ from several other physical and non-physical spot-markets in many ways. This implies that 'perfect' energy spot-markets may inherently be (much) less perfect than other spot-markets that have approximated the stage of theoretical perfection

Study on Laser Induced Plasma Produced in Liquid

International Nuclear Information System (INIS)

Tsuda, N.; Yamada, J.

2003-01-01

When an intense laser light is focused in liquid, a hot plasma is produced at the focal spot. The breakdown threshold and the transmittance of sodium choroids solution are observed using excimer laser or YAG laser. The breakdown threshold decreases with increasing NaCl concentration. Threshold intensity of plasma produced by YAG laser is lower than excimer laser. The behavior of plasma development is observed by a streak camera. The plasma produced by a YAG laser develops only backward. However, the plasma produced by excimer laser develops not only backward but also forward same as the plasma development in high-pressure gases

The effect of low-temperature plasma on model organism Drosophila melanogaster

International Nuclear Information System (INIS)

Maronek, M.; Mentelova, L.; Kyzek, S.; Kovacik, D.

2017-01-01

The occurrence of various chemicals in our life creates a need to evaluate whether they pose a threat to human body. There are many methods capable of detecting potential mutagenic or genotoxic effect. The Smart test was chosen to test mutagenic effect of low-temperature plasma, which is nowadays used in medicine, material decontamination and degradation of pharmaceuticals. When a mutational event during larval development occurs, spots on the wings are being formed. The frequency and size of the spots reveals the mutagenic potency of the tested substance. To evaluate the mutagenic effect of low-temperature plasma, larvae were treated with multiple doses. Our results show that plasma did not exhibit any mutagenic effect in all of the tested doses. Next we studied if it could work as an antimutagenic agent. Experiments with plasma along with ethyl methanesulphonate (EMS), a known mutagen, suggest that plasma treatment did reduce the negative effect of EMS, thus this agents could possess antimutagenic effect. (authors)

DISC Predictive Scales (DPS): Factor Structure and Uniform Differential Item Functioning Across Gender and Three Racial/Ethnic Groups for ADHD, Conduct Disorder, and Oppositional Defiant Disorder Symptoms

OpenAIRE

Wiesner, Margit; Kanouse, David E.; Elliott, Marc N.; Windle, Michael; Schuster, Mark A.

2015-01-01

The factor structure and potential uniform differential item functioning (DIF) among gender and three racial/ethnic groups of adolescents (African American, Latino, White) were evaluated for attention deficit/hyperactivity disorder (ADHD), conduct disorder (CD), and oppositional defiant disorder (ODD) symptom scores of the DISC Predictive Scales (DPS; Leung et al., 2005; Lucas et al., 2001). Primary caregivers reported on DSM–IV ADHD, CD, and ODD symptoms for a probability sample of 4,491 chi...

Ignition target and laser-plasma instabilities

International Nuclear Information System (INIS)

Laffite, S.; Loiseau, P.

2010-01-01

For the first time indirect drive ignition targets have been designed with the constraint of limiting laser-plasma instabilities. The amplification of these instabilities is directly proportional to the luminous flux density, it means to the sizes of the focal spots too. This study shows that increasing the sizes of the focal spots does not reduce linear amplification gains in a proportional way because the global optimization of the target implies changes in hydrodynamical conditions that in turn have an impact on the value of the amplification gain. The design of the target is a 2-step approach: the first step aims at assuring a uniform irradiation and compression of the target. The first step requires information concerning the laser focusing spots, the dimensions of the hohlraum, the inert gas contained in it, the materials of the wall. The second step is an optimization approach whose aim is to reduce the risk of laser-plasmas instabilities. This optimization is made through simulations of the amplification gains of stimulated Raman and Brillouin backscattering. This method has allowed us to design an optimized target for a rugby-shaped hohlraum. (A.C.)

A simple method to quantitate IP-10 in dried blood and plasma spots

DEFF Research Database (Denmark)

Aabye, Martine G; Eugen-Olsen, Jesper; Werlinrud, Anne Marie

2012-01-01

Antigen specific release of IP-10 is an established marker for infection with M.tuberculosis. Compared to IFN-γ, IP-10 is released in 100-fold higher concentrations enabling the development of novel assays for detection. Dried blood spots are a convenient sample for high throughput newborn...

Observations of solar flare transition zone plasmas from the Solar Maximum Mission

Science.gov (United States)

Cheng, C.-C.; Bruner, E. C.; Tandberg-Hanssen, E.; Woodgate, B. E.; Shine, R. A.; Kenny, P. J.; Henze, W.; Poletto, G.

1982-01-01

The spatial and temporal evolution of the Si IV and O IV intensity, density and mass motions in preflare and flare transition zone plasmas are studied for the case of the April 8, 1980 flare. It is found that: (1) the UV flare observed in the Si IV and O IV lines is unambiguously identified as occurring in a low-lying, preexisting transition zone loop which spanned the magnetic neutral line separating a larger leader spot and a newly emerged, isolated spot of opposite polarity; (2) at the onset of the flare, the easternmost footpoint, which was anchored in an isolated spot region of high longitudinal magnetic field gradient, showed sudden, impulsive brightening with large intensity increases; and (3) the release flare energy was transported by way of large-scale connecting field lines to other parts of the active region, producing the hot plasma and H-alpha kernels observed near the trailing spot.

Characterization of LIL laser UV focal spot

International Nuclear Information System (INIS)

Mangeant, M.; Dubois, J.L.; Behar, G.; Arroyo, P.; Durand, V.; Lahonde, C.

2006-01-01

One way to get the fusion of hydrogen in laboratory consists in heating and compressing a DT fuel capsule by using a laser. To reach this aim requires a new generation of high power laser facility. Cea (French board for atomic energy) is developing for this purpose a new 240 laser line facility, the LMJ facility. The LIL which is the prototype of four LMJ laser lines is operational now. In order to confirm the technical choices, a systematic characterization of LIL was carried out. A particular effort has been provided to measure the 3ω high energy focal spot (1.5 kJ/700 ps and 5 ns for one beam) and the synchronization of laser beams onto the target, which are key issues for the plasma production. An experimental device, SAT-3ω (a 3ω laser focal spot analysis) has been designed to perform these measures. That diagnostic which is located at the end of the laser lines delivered its first results during the 2004 quadruplet qualification campaigns. The near field imaging showed no diaphony and vignetting. Low power spots allowed us to control we had no ghost. The energy measurement quality showed the photometric transfer function was perfectly known. Our caustic image are given with an average dynamic range of 800, a spatial resolution of 10 μm and diameter accuracy about 1% for 50% and 3% for 90% of encircled energy. The high energy focal spot diameters are in agreement with low and very low energy diameters. The phase plate and 14 GHz effects are similar to what we had expected. For a laser shot completed with a continuous phase plate at 14 GHz, and for an energy level of 1.5 kJ per beam at 351 nm, the focal beam diameter at 3% of the peak level is (875 ± 45) μm

Spot Size Limited Carbon Propellant Characterization for Efficient High Isp Laser Propulsion

International Nuclear Information System (INIS)

Uchida, Shigeaki; Shimada, Yoshinori; Hashimoto, Kazuhisa; Yamaura, Michiteru; Birou, Tomoya; Yoshida, Minoru

2005-01-01

Laser propulsion has very unique advantage of producing exhausting gas (ions) of very high velocity. Specific impulse from laser plasma could easily exceed 10,000 seconds that reduce the current propellant consumption rate on space born thrusters significantly. For efficient propellant usage, it is desirable that the exhaust plasma has rather narrow velocity distribution of fast ions. In order to accomplish the requirements, thermal conduction and neutral particle losses at and vicinity of the laser heated region have to be eliminated. A concept of spot size limited propellant shape has been proposed and tested in terms of the effects of the loss reduction. Ion and neutral particle measurements from laser plasmas produced on the above mentioned carbon targets are used to characterize the performance of the propellant

Investigation of stability and x-ray spectrum in gas-puff z-pinch plasmas diriven by inductive energy storage pulsed power generator with a plasma opening switch

International Nuclear Information System (INIS)

Murayama, K.; Fukudome, I.; Teramoto, Y.; Katsuki, S.; Akiyama, H.

2002-01-01

Gas-puff z-pinch plasmas are driven by an inductive voltage adder - inductive energy storage pulsed power generator ''ASO-X''. ASO-X has the performance of the maximum output voltage and current are 180 kV and 400 kA respectively and can provide a fast rise time current with operating POS. The stability of the plasma column, spectrum radiated from z-pinch plasmas and the spatial distribution of hot spots are investigated in the case with and without operating POS. By driving ASO-X with operating POS the kink instability is restrained and the stability of plasma column is improved about three times in regard to the average dispersion. Furthermore the duration of soft x-ray radiation is increased and the spatial distribution of hot spots is 50% improved with regard to kurtosis of the intensity profile of pinhole photographs compared to those without operating POS. (author)

Dried Blood Spot Methodology in Combination With Liquid Chromatography/Tandem Mass Spectrometry Facilitates the Monitoring of Teriflunomide

Science.gov (United States)

Lunven, Catherine; Turpault, Sandrine; Beyer, Yann-Joel; O'Brien, Amy; Delfolie, Astrid; Boyanova, Neli; Sanderink, Ger-Jan; Baldinetti, Francesca

2016-01-01

Background: Teriflunomide, a once-daily oral immunomodulator approved for treatment of relapsing-remitting multiple sclerosis, is eliminated slowly from plasma. If necessary to rapidly lower plasma concentrations of teriflunomide, an accelerated elimination procedure using cholestyramine or activated charcoal may be used. The current bioanalytical assay for determination of plasma teriflunomide concentration requires laboratory facilities for blood centrifugation and plasma storage. An alternative method, with potential for greater convenience, is dried blood spot (DBS) methodology. Analytical and clinical validations are required to switch from plasma to DBS (finger-prick sampling) methodology. Methods: Using blood samples from healthy subjects, an LC-MS/MS assay method for quantification of teriflunomide in DBS over a range of 0.01–10 mcg/mL was developed and validated for specificity, selectivity, accuracy, precision, reproducibility, and stability. Results were compared with those from the current plasma assay for determination of plasma teriflunomide concentration. Results: Method was specific and selective relative to endogenous compounds, with process efficiency ∼88%, and no matrix effect. Inaccuracy and imprecision for intraday and interday analyses were blood deposit volume and punch position within spot, and hematocrit level had a limited but acceptable effect on measurement accuracy. Teriflunomide was stable for at least 4 months at room temperature, and for at least 24 hours at 37°C with and without 95% relative humidity, to cover sampling, drying, and shipment conditions in the field. The correlation between DBS and plasma concentrations (R2 = 0.97), with an average blood to plasma ratio of 0.59, was concentration independent and constant over time. Conclusions: DBS sampling is a simple and practical method for monitoring teriflunomide concentrations. PMID:27015245

Pooled HIV-1 viral load testing using dried blood spots to reduce the cost of monitoring antiretroviral treatment in a resource-limited setting.

Science.gov (United States)

Pannus, Pieter; Fajardo, Emmanuel; Metcalf, Carol; Coulborn, Rebecca M; Durán, Laura T; Bygrave, Helen; Ellman, Tom; Garone, Daniela; Murowa, Michael; Mwenda, Reuben; Reid, Tony; Preiser, Wolfgang

2013-10-01

Rollout of routine HIV-1 viral load monitoring is hampered by high costs and logistical difficulties associated with sample collection and transport. New strategies are needed to overcome these constraints. Dried blood spots from finger pricks have been shown to be more practical than the use of plasma specimens, and pooling strategies using plasma specimens have been demonstrated to be an efficient method to reduce costs. This study found that combination of finger-prick dried blood spots and a pooling strategy is a feasible and efficient option to reduce costs, while maintaining accuracy in the context of a district hospital in Malawi.

Validation and clinical application of a method to quantify nevirapine in dried blood spots and dried breast-milk spots.

Science.gov (United States)

Olagunju, Adeniyi; Amara, Alieu; Waitt, Catriona; Else, Laura; Penchala, Sujan D; Bolaji, Oluseye; Soyinka, Julius; Siccardi, Marco; Back, David; Owen, Andrew; Khoo, Saye

2015-10-01

The validation and clinical application of an LC-MS/MS method for the quantification of nevirapine in dried blood spots (DBS) and dried breast-milk spots (DBMS) are presented. DBS and DBMS were prepared from 50 and 30 μL of nevirapine-spiked whole blood and human breast milk, respectively. Chromatographic separation was achieved on a reverse-phase C18 column with 0.1% formic acid in water/acetonitrile using a solvent gradient programme at a flow rate of 400 μL/min, and detection was by a TSQ Quantum Access triple quadrupole mass spectrometer. The clinical application was evaluated in HIV-positive nursing mothers and their breastfed infants. The assay was validated over the concentration range 50-10,000 ng/mL. Accuracy ranged from 93.3% to 113.4% and precision ranged from 1.9% to 12.0%. The mean (percentage coefficient of variation) recovery of nevirapine from DBS and DBMS was ≥ 70.7% (≤ 8.2) and the matrix effect was ≤ 1.04 (≤ 6.1). Nevirapine was stable in DBS and DBMS for ≥ 15 months at room temperature and -80°C. Mean (SD) AUC0-12, Cmax and Cmin in maternal plasma versus breast milk were 57,808 ng · h/mL (24,315) versus 55,817 ng · h/mL (22,368), 6140 ng/mL (2605) versus 5231 ng/mL (2215) and 4334 ng/mL (1880) versus 4342 ng/mL (2245), respectively. The milk-to-plasma concentration ratio over the dosing interval was 0.94 (0.15). Infant plasma concentrations 2 and 8 h after maternal dosing were 580.6 ng/mL (464.7-1607) and 584.1 ng/mL (381.5-1570), respectively. These methods further extend opportunities for conducting clinical pharmacokinetic studies in nursing mother-infant pairs, especially in resource-limited settings. © The Author 2015. Published by Oxford University Press on behalf of the British Society for Antimicrobial Chemotherapy. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.

Plasma and breast milk pharmacokinetics of emtricitabine, tenofovir and lamivudine using dried blood and breast milk spots in nursing African mother–infant pairs

Science.gov (United States)

Waitt, Catriona; Olagunju, Adeniyi; Nakalema, Shadia; Kyohaire, Isabella; Owen, Andrew; Lamorde, Mohammed; Khoo, Saye

2018-01-01

Abstract Background Breast milk transfer of first-line ART from mother to infant is not fully understood. Objectives To determine the concentrations of lamivudine, emtricitabine and tenofovir in maternal blood, breast milk and infant blood from breastfeeding mother–infant pairs. Methods Intensive pharmacokinetic sampling of maternal dried blood spots (DBS), dried breast milk spots (DBMS) and infant DBS from 30 Ugandan and 29 Nigerian mothers receiving first-line ART and their infants was conducted. DBS and DBMS were collected pre-dose and at 5–6 timepoints up to 12 h following observed dosing. Infant DBS were sampled twice during this period. Lamivudine, emtricitabine and tenofovir were quantified using LC-MS/MS, with non-compartmental analysis to calculate key pharmacokinetic parameters. Results Peak concentrations in breast milk from women taking lamivudine and emtricitabine occurred later than in plasma (4–8 h compared with 2 h for lamivudine and 2–4 h for emtricitabine). Consequently, the milk-to-plasma (M:P) ratio of lamivudine taken once daily was 0.95 (0.82–1.15) for AUC0–12, whereas for AUC12–20 this was 3.04 (2.87–4.16). Lamivudine was detectable in 36% (14/39) of infants [median 17.7 (16.3–22.7) ng/mL]. For 200 mg of emtricitabine once daily, the median M:P ratio was 3.01 (2.06–3.38). Three infants (19%) had measurable emtricitabine [median 18.5 (17.6–20.8) ng/mL]. For 300 mg of tenofovir once daily, the median M:P ratio was 0.015 (0–0.03) and no infant had measurable tenofovir concentrations. Conclusions Emtricitabine and lamivudine accumulate in breast milk and were detected in breastfeeding infants. In contrast, tenofovir penetrates the breast milk to a small degree, but is undetectable in breastfeeding infants. PMID:29309634

HEAVY ION FUSION SCIENCE VIRTUAL NATIONAL LABORATORY 3nd QUARTER 2009 MILESTONE REPORT: Upgrade plasma source configuration and carry out initial experiments. Characterize improvements in focal spot beam intensity

International Nuclear Information System (INIS)

Lidia, S.; Anders, A.; Barnard, J.J.; Bieniosek, F.M.; Dorf, M.; Faltens, A.; Friedman, A.; Gilson, E.; Greenway, W.; Grote, D.; Jung, J.Y.; Katayanagi, T.; Logan, B.G.; Lee, C.W.; Leitner, M.; Ni, P.; Pekedis, A.; Regis, M. J.; Roy, P. K.; Seidl, P. A.; Waldron, W.

2009-01-01

Simulations suggest that the plasma density must exceed the beam density throughout the drift compression and focusing section in order to inhibit the space charge forces that would limit the spot size and beam intensity on the target. WDM experiments will therefore require plasma densities up to 10 14 /cm 3 , with the highest density in the last few centimeters before the target. This work was guided by the simulations performed for the FY09 Q1 milestone. This milestone has been met and we report results of modifications made to the NDCX beamline to improve the longitudinal and radial distribution of the neutralizing plasma in the region near the target plane. In Section 2, we review pertinent simulation results from the FY09 Q1 milestone. Section 3 describes the design, and beam measurements following installation, of a biased, self-supporting metal grid that produces neutralizing electrons from glancing interception of beam ions. Section 4 describes the design and initial testing of a compact Ferro-Electric Plasma Source (FEPS) that will remove the remaining 'exclusion zone' in the neutralizing plasma close to the target plane. Section 5 describes the modification of the beamline to decrease the gap between the FEPS section exit and the final focus solenoid (FFS). Section 6 presents a summary and conclusions.

Photoelectric method for determination of the moment of formation of an anodic spot

International Nuclear Information System (INIS)

Barinov, V.N.; Goncharov, V.K.; Smirnov, A.V.

1986-01-01

In studying the problem of the effect of the amplitude and form of discharge current pulses on the time for transition from a diffuse discharge form to a contracted one and on the value of the threshold current I /SUB As/ for formation of an anodic spot, the authors used a photoelectric method for determination of the moment of appearance of the anodic spot based on determination of the spectral composition of the plasma at different moments of time after the beginning of discharge initiation. The photoelectric method can be used in studying emission processes on a cathode and also in those cases where both electrodes are made of the same material. An example shows synchronous oscillograms of I /SUB p/ (tau) and J /SUB i/ (tau) for copper electrodes. It is evident that during transition of the discharge to a contracted form with an anodic spot there was a sharp increase of the intensity of deexcitation of the ionic copper line. At the moment of extinction of the anodic spot, the amplitude values of J /SUB i/ (tau) corresponded to a level characteristic of the diffuse form of arc burning

Rocky Mountain spotted fever

Science.gov (United States)

... spotted fever on the foot Rocky Mountain spotted fever, petechial rash Antibodies Deer and dog tick References McElligott SC, Kihiczak GG, Schwartz RA. Rocky Mountain spotted fever and other rickettsial infections. In: Lebwohl MG, Heymann ...

Effect of diffraction on stimulated Brillouin scattering from a single laser hot spot

International Nuclear Information System (INIS)

Eliseev, V.V.; Rozmus, W.; Tikhonchuk, V.T.; Capjack, C.E.

1996-01-01

A single laser hot spot in an underdense plasma is represented as a focused Gaussian laser beam. Stimulated Brillouin scattering (SBS) from such a Gaussian beam with small f/numbers 2-4 has been studied in a three-dimensional slab geometry. It is shown that the SBS reflectivity from a single laser hot spot is much lower than that predicted by a simple three wave coupling model because of the diffraction of the scattered light from the spatially localized ion acoustic wave. SBS gain per one Rayleigh length of the incident laser beam is proposed as a quantitative measure of this effect. Diffraction-limited SBS from a randomized laser beam is also discussed. copyright 1996 American Institute of Physics

Investigation of stability and x-ray spectrum in gas-puff z-pinch plasmas diriven by inductive energy storage pulsed power generator with a plasma opening switch

Energy Technology Data Exchange (ETDEWEB)

Murayama, K.; Fukudome, I. [Yatsushiro National College of Technology, Dept. of Mechanical and Electrical Engineering, Yatsushiro, Kumamoto (Japan); Teramoto, Y.; Katsuki, S.; Akiyama, H. [Kumamoto Univ., Dept. of Electrical and Computer Engineering, Kumamoto (Japan)

2002-06-01

Gas-puff z-pinch plasmas are driven by an inductive voltage adder - inductive energy storage pulsed power generator ''ASO-X''. ASO-X has the performance of the maximum output voltage and current are 180 kV and 400 kA respectively and can provide a fast rise time current with operating POS. The stability of the plasma column, spectrum radiated from z-pinch plasmas and the spatial distribution of hot spots are investigated in the case with and without operating POS. By driving ASO-X with operating POS the kink instability is restrained and the stability of plasma column is improved about three times in regard to the average dispersion. Furthermore the duration of soft x-ray radiation is increased and the spatial distribution of hot spots is 50% improved with regard to kurtosis of the intensity profile of pinhole photographs compared to those without operating POS. (author)

The Spotting Distribution of Wildfires

Directory of Open Access Journals (Sweden)

Jonathan Martin

2016-06-01

Full Text Available In wildfire science, spotting refers to non-local creation of new fires, due to downwind ignition of brands launched from a primary fire. Spotting is often mentioned as being one of the most difficult problems for wildfire management, because of its unpredictable nature. Since spotting is a stochastic process, it makes sense to talk about a probability distribution for spotting, which we call the spotting distribution. Given a location ahead of the fire front, we would like to know how likely is it to observe a spot fire at that location in the next few minutes. The aim of this paper is to introduce a detailed procedure to find the spotting distribution. Most prior modelling has focused on the maximum spotting distance, or on physical subprocesses. We will use mathematical modelling, which is based on detailed physical processes, to derive a spotting distribution. We discuss the use and measurement of this spotting distribution in fire spread, fire management and fire breaching. The appendix of this paper contains a comprehensive review of the relevant underlying physical sub-processes of fire plumes, launching fire brands, wind transport, falling and terminal velocity, combustion during transport, and ignition upon landing.

Measurement of the development and evolution of shock waves in a laser-induced gas breakdown plasma

International Nuclear Information System (INIS)

Chu, T.K.; Johnson, L.C.

1975-01-01

Space- and time-resolved interferometric measurements of electron density in CO 2 -laser produced plasmas in helium or hydrogen are made near the laser focal spot. Immediately after breakdown, a rapidly growing region of approximately uniform plasma density appears at the focal spot. After a few tens of nanoseconds, shock waves are formed, propagating both transverse and parallel to the incident laser beam direction. Behind the transverse propagating shock is an on-axis density minimum, which results in laser-beam self-trapping. The shock wave propagating toward the focusing lens effectively shields the interior plasma from the incident beam because the lower plasma temperature and higher plasma density in the shock allow strong absorption of the incident beam energy. By arranging the laser radiation-plasma interaction to begin at a plasma-vacuum interface at the exit of a free-expansion jet, this backward propagating shock wave is eliminated, thus permitting efficient energy deposition in the plasma interior

Relationship between hot spot residues and ligand binding hot spots in protein-protein interfaces.

Science.gov (United States)

Zerbe, Brandon S; Hall, David R; Vajda, Sandor; Whitty, Adrian; Kozakov, Dima

2012-08-27

In the context of protein-protein interactions, the term "hot spot" refers to a residue or cluster of residues that makes a major contribution to the binding free energy, as determined by alanine scanning mutagenesis. In contrast, in pharmaceutical research, a hot spot is a site on a target protein that has high propensity for ligand binding and hence is potentially important for drug discovery. Here we examine the relationship between these two hot spot concepts by comparing alanine scanning data for a set of 15 proteins with results from mapping the protein surfaces for sites that can bind fragment-sized small molecules. We find the two types of hot spots are largely complementary; the residues protruding into hot spot regions identified by computational mapping or experimental fragment screening are almost always themselves hot spot residues as defined by alanine scanning experiments. Conversely, a residue that is found by alanine scanning to contribute little to binding rarely interacts with hot spot regions on the partner protein identified by fragment mapping. In spite of the strong correlation between the two hot spot concepts, they fundamentally differ, however. In particular, while identification of a hot spot by alanine scanning establishes the potential to generate substantial interaction energy with a binding partner, there are additional topological requirements to be a hot spot for small molecule binding. Hence, only a minority of hot spots identified by alanine scanning represent sites that are potentially useful for small inhibitor binding, and it is this subset that is identified by experimental or computational fragment screening.

SPOT Program

Science.gov (United States)

Smith, Jason T.; Welsh, Sam J.; Farinetti, Antonio L.; Wegner, Tim; Blakeslee, James; Deboeck, Toni F.; Dyer, Daniel; Corley, Bryan M.; Ollivierre, Jarmaine; Kramer, Leonard;

Observations of dense plasma formation in the vacuum spark

International Nuclear Information System (INIS)

Chuaqui, H.; Favre, M.; Wyndham, E.; Aliaga R, R.; Choi, P.; Dumitrescu-Zoita, C.

1994-01-01

A series of experimental observations have been performed on the dense plasma formations or Hot Spots generated in the Vacuum Spark. The plasma discharges are driven by a 1.5 Ohm, 120 ns line at currents up to 100 KA. The line may be used to deliver a rectangular current pulse when the line gap is used. Alternatively when the line gap is shorted, the Vacuum Spark itself switches the line. A Nd: Yag Laser, with an energy of 0.5 J in an 8 ns pulse, is used to pre ionizing the discharge. The formation of Hot Spots is studied under a range of different conditions. These include the pre ionizing conditions, as well as the Anode shape and the Anode Cathode separation. The optimization of these parameters permit very reproducible shot to shot behaviour. Of particular interest is the Hot Spot size dependence as a function of its temperature and of time. The use of a new variant on the Pin Hole Camera, the Slit Wire Camera provides a new method of measuring with precision the Hot Spot dimensions in different X-ray emission energy ranges. A quadruple hole Camera is used to measure the temperature of the Hot Spots. The temporal and spatial evolution of the X-ray emission is measured using using a Slit Wire, Scintillator, Fibre Optic, Photomultiplier array. The temporal emission of the X-rays is also observed using an array of PIN X-ray diodes. (author). 5 refs, 6 figs

Heat flow during sawtooth collapse in tokamak plasmas

International Nuclear Information System (INIS)

Hanada, Kazuaki

1994-01-01

Heat flow during sawtooth collapse was studied on the WT-3 tokamak by using temporal evolution of soft X-ray intensity profile in the poloidal cross section in a lower hybrid current driven plasma as well as an electron cyclotron heated plasma. Two phase in sawtooth collapses were observed. In the first phases, the hottest spot that is the peak of the soft X-ray distribution approaches the inversion surface and heat flows out through a narrow gate on the inversion surface. In the second phase, the hottest spot stays on the inversion surface, and heat flows out through the whole inversion surface. This suggests that magnetic reconnection as predicted by Kadomtsev's model occurs in the first phase, but in the second phase, a different mechanism dominates heat flow. (author)

Effects of spot size and spot spacing on lateral penumbra reduction when using a dynamic collimation system for spot scanning proton therapy

International Nuclear Information System (INIS)

Hyer, Daniel E; Hill, Patrick M; Wang, Dongxu; Smith, Blake R; Flynn, Ryan T

2014-01-01

The purpose of this work was to investigate the reduction in lateral dose penumbra that can be achieved when using a dynamic collimation system (DCS) for spot scanning proton therapy as a function of two beam parameters: spot size and spot spacing. This is an important investigation as both values impact the achievable dose distribution and a wide range of values currently exist depending on delivery hardware. Treatment plans were created both with and without the DCS for in-air spot sizes (σ air ) of 3, 5, 7, and 9 mm as well as spot spacing intervals of 2, 4, 6 and 8 mm. Compared to un-collimated treatment plans, the plans created with the DCS yielded a reduction in the mean dose to normal tissue surrounding the target of 26.2–40.6% for spot sizes of 3–9 mm, respectively. Increasing the spot spacing resulted in a decrease in the time penalty associated with using the DCS that was approximately proportional to the reduction in the number of rows in the raster delivery pattern. We conclude that dose distributions achievable when using the DCS are comparable to those only attainable with much smaller initial spot sizes, suggesting that the goal of improving high dose conformity may be achieved by either utilizing a DCS or by improving beam line optics. (note)

On the origin of delta spots

International Nuclear Information System (INIS)

Tang, F.

1983-01-01

Mount Wilson sunspot drawings from 1966 through 1980 were used in conjunction with Hα filtergrams from Big Bear Solar Observatory to examine the origin of delta spots, spots with bipolar umbrae within one penumbra. Of the six cases we studied, five were formed by the union of non-paired spots. They are either shoved into one another by two neighboring growing bipoles or by a new spot born piggy-back style on an existing spot of opposite polarity. Proper motions of the growing spots take on curvilinear paths around one another to avoid a collision. This is the shear motion observed in delta spots (Tanaka, 1979). In the remaining case, the delta spot was formed by spots that emerged as a pair. Our findings indicate no intrinsic differences in the formation or the behavior between delta spots of normal magnetic configuration. (orig.)

RECURRENT SOLAR JETS INDUCED BY A SATELLITE SPOT AND MOVING MAGNETIC FEATURES

Energy Technology Data Exchange (ETDEWEB)

Chen, Jie; Su, Jiangtao; Yin, Zhiqiang; Priya, T. G.; Zhang, Hongqi; Xu, Haiqing; Yu, Sijie [Key Laboratory of Solar Activity, National Astronomical Observatories, Chinese Academy of Sciences, Beijing 100012 (China); Liu, Jihong, E-mail: chenjie@bao.ac.cn [Shi Jiazhuang University, Shi Jiazhuang, 050035 (China)

2015-12-10

Recurrent and homologous jets were observed to the west edge of active region NOAA 11513 at the boundary of a coronal hole. We find two kinds of cancellations between opposite polarity magnetic fluxes, inducing the generation of recurrent jets. First, a satellite spot continuously collides with a pre-existing opposite polarity magnetic field and causes recurrent solar jets. Second, moving magnetic features, which emerge near the sunspot penumbra, pass through the ambient plasma and eventually collide with the opposite polarity magnetic field. Among these recurrent jets, a blowout jet that occurred around 21:10 UT is investigated. The rotation of the pre-existing magnetic field and the shear motion of the satellite spot accumulate magnetic energy, which creates the possibility for the jet to experience blowout right from the standard.

Validation and Application of a Dried Blood Spot Ceftriaxone Assay

Science.gov (United States)

Page-Sharp, Madhu; Nunn, Troy; Salman, Sam; Moore, Brioni R.; Batty, Kevin T.; Davis, Timothy M. E.

2015-01-01

Dried blood spot (DBS) antibiotic assays can facilitate pharmacokinetic/pharmacodynamic (PK/PD) studies in situations where venous blood sampling is logistically and/or ethically problematic. In this study, we aimed to develop, validate, and apply a DBS ceftriaxone assay. A liquid chromatography-tandem mass spectroscopy (LC-MS/MS) DBS ceftriaxone assay was assessed for matrix effects, process efficiency, recovery, variability, and limits of quantification (LOQ) and detection (LOD). The effects of hematocrit, protein binding, red cell partitioning, and chad positioning were evaluated, and thermal stability was assessed. Plasma, DBS, and cell pellet ceftriaxone concentrations in 10 healthy adults were compared, and plasma concentration-time profiles of DBS and plasma ceftriaxone were incorporated into population PK models. The LOQ and LOD for ceftriaxone in DBS were 0.14 mg/liter and 0.05 mg/liter, respectively. Adjusting for hematocrit, red cell partitioning, and relative recovery, DBS-predicted plasma concentrations were comparable to measured plasma concentrations (r > 0.95, P 95% initial concentrations in DBS for 14 h, 35 h, 30 days, 21 weeks, and >11 months, respectively. The present DBS ceftriaxone assay is robust and can be used as a surrogate for plasma concentrations to provide valid PK and PK/PD data in a variety of clinical situations, including in studies of young children and of those in remote or resource-poor settings. PMID:26438505

Staging of laser-plasma accelerators

Energy Technology Data Exchange (ETDEWEB)

Steinke, S., E-mail: ssteinke@lbl.gov; Tilborg, J. van; Benedetti, C.; Geddes, C. G. R.; Gonsalves, A. J.; Nakamura, K.; Schroeder, C. B.; Esarey, E. [Lawrence Berkeley National Laboratory, Berkeley, California 94720 (United States); Daniels, J. [Lawrence Berkeley National Laboratory, Berkeley, California 94720 (United States); Eindhoven University of Technology, PO Box 513, 5600MB Eindhoven (Netherlands); Swanson, K. K.; Shaw, B. H.; Leemans, W. P. [Lawrence Berkeley National Laboratory, Berkeley, California 94720 (United States); University of California, Berkeley, California 94720 (United States)

2016-05-15

We present results of an experiment where two laser-plasma-accelerator stages are coupled at a short distance by a plasma mirror. Stable electron beams from the first stage were used to longitudinally probe the dark-current-free, quasi-linear wakefield excited by the laser of the second stage. Changing the arrival time of the electron beam with respect to the second stage laser pulse allowed reconstruction of the temporal wakefield structure, determination of the plasma density, and inference of the length of the electron beam. The first stage electron beam could be focused by an active plasma lens to a spot size smaller than the transverse wake size at the entrance of the second stage. This permitted electron beam trapping, verified by a 100 MeV energy gain.

effect of the plasma ion channel on self-focusing of a Gaussian laser pulse in underdense plasma

Directory of Open Access Journals (Sweden)

Sh Irani

2013-09-01

Full Text Available  We have considered the self-focusing of a Gaussian laser pulse in unmagnetized plasma. High-intensity electromagnetic fields cause the variation of electron density in plasma. These changes in the special conditions cause the acceleration of electrons to the higher energy and velocities. Thus the equation of plasma density evolution was obtained considering the electrons ponderomotive force. Then, an equation for the width of laser pulse with a relativistic mass correction term and the effect of ion channel were derived and the propagation of high-intensity laser pulse in an underdense plasma with weak relativistic approximation was investigated. It is shown that the ratio of ion channel radius to spot size could result in different forms of self focusing for the laser pulse in plasma.

Spot market for uranium

International Nuclear Information System (INIS)

Colhoun, C.

1982-01-01

The spot market is always quoted for the price of uranium because little information is available about long-term contracts. A review of the development of spot market prices shows the same price curve swings that occur with all raw materials. Future long-term contracts will probably be lower to reflect spot market prices, which are currently in the real-value range of $30-$35. An upswing in the price of uranium could come in the next few months as utilities begin making purchases and trading from stockpiles. The US, unlike Europe and Japan, has already reached a supply and demand point where the spot market share is increasing. Forecasters cannot project the market price, they can only predict the presence of an oscillating spot or a secondary market. 5 figures

Space and time resolved observations of hot spots dynamics in a vacuum spark discharge

International Nuclear Information System (INIS)

Chuaqui, H.; Favre, M.; Saavedra, R.; Wyndham, E.

1996-01-01

Experimental observations of the plasma formations in a vacuum spark discharge are presented. A low power Nd:YAG laser pulse incident onto a titanium cathode initiates the discharge. The evolution of the titanium plasma electron density and temperature is followed both in the visible and the soft X-ray part of the spectrum. The former uses a novel micro holographic interferometric technique permitting a spatial resolution better than 20 μm. The probing beam is a 6 ns frequency doubled Nd:YAG laser. The latter emission is resolved using a number of different methods. The spatial information is derived from a 1 ns multi framing camera X-ray camera which projects the plasma image using four different slit wire pinhole images and six pinhole images, each aperture being filtered differently. The temporal evolution of the emission of each discharge is followed using several silicon PIN diodes. The x-ray spectrum is unfolded from the filter and detector response and interpreted using a collisional radiative package. The hot spots are seen to form in a submillimeter pinch stemming from the incident laser focus which has a life time about 20 ns. The hot spots are much shorter events, reaching substantially higher densities, but involve only part of the line density of the pinch column. (author). 4 figs., 8 refs

Space and time resolved observations of hot spots dynamics in a vacuum spark discharge

Energy Technology Data Exchange (ETDEWEB)

Chuaqui, H; Favre, M; Saavedra, R; Wyndham, E [Universidad Catolica de Chile, Santiago (Chile). Facultad de Fisica; Choi, P; Dumitrescu-Zoita, C [Ecole Polytechnique, Palaiseau (France). Laboratoire de Physique des Milieux Ionises; Soto, L [Comision Chilena de Energia Nuclear, Santiago (Chile)

1997-12-31

Experimental observations of the plasma formations in a vacuum spark discharge are presented. A low power Nd:YAG laser pulse incident onto a titanium cathode initiates the discharge. The evolution of the titanium plasma electron density and temperature is followed both in the visible and the soft X-ray part of the spectrum. The former uses a novel micro holographic interferometric technique permitting a spatial resolution better than 20 {mu}m. The probing beam is a 6 ns frequency doubled Nd:YAG laser. The latter emission is resolved using a number of different methods. The spatial information is derived from a 1 ns multi framing camera X-ray camera which projects the plasma image using four different slit wire pinhole images and six pinhole images, each aperture being filtered differently. The temporal evolution of the emission of each discharge is followed using several silicon PIN diodes. The x-ray spectrum is unfolded from the filter and detector response and interpreted using a collisional radiative package. The hot spots are seen to form in a submillimeter pinch stemming from the incident laser focus which has a life time about 20 ns. The hot spots are much shorter events, reaching substantially higher densities, but involve only part of the line density of the pinch column. (author). 4 figs., 8 refs.

Pulmonary function abnormalities and airway irritation symptoms of metal fumes exposure on automobile spot welders.

Science.gov (United States)

Luo, Jiin-Chyuan John; Hsu, Kuang-Hung; Shen, Wu-Shiun

2006-06-01

Spot or resistance welding has been considered less hazardous than other types of welding. Automobile manufacturing is a major industry in Taiwan. Spot and arc welding are common processes in this industry. The respiratory effects on automobile spot welders exposed to metal fumes are investigated. The cohort consisted of 41 male auto-body spot welders, 76 male arc welders, 71 male office workers, and 59 assemblers without welding exposure. Inductivity Coupled Plasma Mass Spectrophotometer (ICP-MS) was applied to detect metals' (zinc, copper, nickel) levels in the post-shift urine samples. Demographic data, work history, smoking status, and respiratory tract irritation symptoms were gathered by a standard self-administered questionnaire. Pulmonary function tests were also performed. There were significantly higher values for average urine metals' (zinc, copper, nickel) levels in spot welders and arc welders than in the non-welding controls. There were 4 out of 23 (17.4%) abnormal forced vital capacity (FVC) among the high-exposed spot welders, 2 out of 18 (11.1%) among the low-exposed spot welders, and 6 out of 130 (4.6%) non-welding-exposed workers. There was a significant linear trend between spot welding exposure and the prevalence of restrictive airway abnormalities (P = 0.036) after adjusting for other factors. There were 9 out of 23 (39.1%) abnormal peak expiratory flow rate (PEFR) among high-exposed spot welders, 5 out of 18 (27.8%) among the low-exposed spot welders, and 28 out of 130 (21.5%) non-welding-exposed workers. There was a borderline significant linear trend between spot welding exposure and the prevalence of obstructive lung function abnormalities (P = 0.084) after adjusting for other factors. There was also a significant dose-response relationship of airway irritation symptoms (cough, phlegm, chronic bronchitis) among the spot welders. Arc welders with high exposure status also had a significant risk of obstructive lung abnormalities (PEFR

Roth spots in pernicious anaemia.

Science.gov (United States)

Macauley, Mavin; Nag, Satyajit

2011-04-19

Roth spots are white-centred retinal haemorrhages, previously thought to be pathognomonic for subacute bacterial endocarditis. A number of other conditions can be associated with Roth spots. In this case, the authors describe the association of Roth spots and pernicious anaemia. This association has been rarely described in the medical literature. Correct diagnosis and treatment with intramuscular vitamin B(12) injections resulted in complete resolution of the anaemia and Roth spots. The authors hope to alert clinicians to think of various differentials of Roth spots, and initiate prompt investigation and management.

Comparison of outcomes between overlapping-spot and single-spot photodynamic therapy for circumscribed choroidal hemangioma

Directory of Open Access Journals (Sweden)

Zhao-An Su

2014-02-01

Full Text Available AIM:To compare the efficacy and safety of photodynamic therapy (PDT with overlapping multiple spots and single spot for treating circumscribed choroidal hemangioma.METHODS:Twenty-two patients (22 eyes with symptomatic circumscribed choroidal hemangioma received PDT treatment. Fourteen patients received overlapping spots (two to three spots PDT, whereas eight patients received single-spot PDT. Laser was used at 50J/cm2 for 83s in the overlapping-spot group and 50J/cm2 for 166s in the single-spot group. Clinical examination, funduscopy, fluorescein angiography, and ultrasonography were performed at baseline and after treatment.RESULTS:The mean follow-up time was 28.5±8.0 months in the overlapping-spot group and 27.0±5.0 months in the single-spot group. Nine patients (64.2% had their vision improved over two lines on the Snellen chart, and five patients showed stable visual acuity in the overlapping-spot group. The mean thickness of tumor decreased from 2.7±0.8mm to 1.2±0.9mm, and the mean greatest tumor linear dimension decreased from 7.4±1.5mm to 4.5±3.5mm after treatment. In the single-spot group, two patients (25% had their vision improved over two lines on the Snellen chart, and six patients had unchanged stable vision. The mean tumor thickness in this group decreased from 2.5±0.7mm to 1.4±1.0mm, and the mean greatest tumor linear dimension decreased from 7.2±1.3mm to 4.7±3.6mm. No significant differences in visual improvement and tumor regression were found between the two groups.CONCLUSION: Overlapping-spot PDT under appropriate treatment parameters and strategies is as effective and safe as single-spot PDT for treating symptomatic circumscribed choroidal hemangioma. Improved or stabilized visual acuity was achieved as a result of tumor regression.

Effect of the laser spot shape on spatial distribution of the ion bunch accelerated in a superstrong field

International Nuclear Information System (INIS)

Scientific research Institute for Optoelectronic Instrument Engineering, Leningrad region (Russian Federation))" data-affiliation=" (Public Limited Company Scientific research Institute for Optoelectronic Instrument Engineering, Leningrad region (Russian Federation))" >Komarov, V M; Scientific research Institute for Optoelectronic Instrument Engineering, Leningrad region (Russian Federation))" data-affiliation=" (Public Limited Company Scientific research Institute for Optoelectronic Instrument Engineering, Leningrad region (Russian Federation))" >Charukhchev, A V; S.I.Vavilov State Optical Institute (FSUE GOI), St.Petersburg (Russian Federation))" data-affiliation=" (Federal State Unitary Enterprise All-Russian Scientific Center S.I.Vavilov State Optical Institute (FSUE GOI), St.Petersburg (Russian Federation))" >Andreev, A A; S.I.Vavilov State Optical Institute (FSUE GOI), St.Petersburg (Russian Federation))" data-affiliation=" (Federal State Unitary Enterprise All-Russian Scientific Center S.I.Vavilov State Optical Institute (FSUE GOI), St.Petersburg (Russian Federation))" >Platonov, K Yu

2014-01-01

We have investigated the effect of the laser spot shape on the spatial distribution of accelerated ions on the front and back sides of a thin target irradiated by a picosecond laser pulse having the intensity of (3 – 4) × 10 18 W cm -2 . Experimental data are compared with numerical calculations. It is shown that the spatial structure of the ion bunch on the front side of the target resembles the laser spot structure rotated by 90°. (interaction of laser radiation with matter. laser plasma)

Effect of the laser spot shape on spatial distribution of the ion bunch accelerated in a superstrong field

Energy Technology Data Exchange (ETDEWEB)

Komarov, V M; Charukhchev, A V [Public Limited Company " Scientific research Institute for Optoelectronic Instrument Engineering" , Leningrad region (Russian Federation); Andreev, A A; Platonov, K Yu [Federal State Unitary Enterprise All-Russian Scientific Center " S.I.Vavilov State Optical Institute" (FSUE GOI), St.Petersburg (Russian Federation)

2014-12-31

We have investigated the effect of the laser spot shape on the spatial distribution of accelerated ions on the front and back sides of a thin target irradiated by a picosecond laser pulse having the intensity of (3 – 4) × 10{sup 18} W cm{sup -2}. Experimental data are compared with numerical calculations. It is shown that the spatial structure of the ion bunch on the front side of the target resembles the laser spot structure rotated by 90°. (interaction of laser radiation with matter. laser plasma)

Quantification of underivatised amino acids on dry blood spot, plasma, and urine by HPLC-ESI-MS/MS.

Science.gov (United States)

Giordano, Giuseppe; Di Gangi, Iole Maria; Gucciardi, Antonina; Naturale, Mauro

2012-01-01

Enzyme deficiencies in amino acid (AA) metabolism affecting the levels of amino acids and their derivatives in physiological fluids may serve as diagnostically significant biomarkers for one or a group of metabolic disorders. Therefore, it is important to monitor a wide range of free amino acids simultaneously and to quantify them. This is time consuming if we use the classical methods and more than ever now that many laboratories have introduced Newborn Screening Programs for the semiquantitative analysis, detection, and quantification of some amino acids needed to be performed in a short time to reduce the rate of false positives.We have modified the stable isotope dilution HPLC-electrospray ionization (ESI)-MS/MS method previously described by Qu et al. (Anal Chem 74: 2034-2040, 2002) for a more rapid, robust, sensitive, and specific detection and quantification of underivatised amino acids. The modified method reduces the time of analysis to 10 min with very good reproducibility of retention times and a better separation of the metabolites and their isomers.The omission of the derivatization step allowed us to achieve some important advantages: fast and simple sample preparation and exclusion of artefacts and interferences. The use of this technique is highly sensitive, specific, and allows monitoring of 40 underivatized amino acids, including the key isomers and quantification of some of them, in order to cover many diagnostically important intermediates of metabolic pathways.We propose this HPLC-ESI-MS/MS method for underivatized amino acids as a support for the Newborn Screening as secondary test using the same dried blood spots for a more accurate and specific examination in case of suspected metabolic diseases. In this way, we avoid plasma collection from the patient as it normally occurs, reducing anxiety for the parents and further costs for analysis.The same method was validated and applied also to plasma and urine samples with good reproducibility

Summary abstract: microspot target development with seeded and patterned plasma polymers

International Nuclear Information System (INIS)

Letts, S.A.; Miller, D.E.; Corley, R.A.; Tillotson, T.M.; Witt, L.A.

1985-01-01

In inertial confinement fusion (ICF) energy is transferred from the laser to the target through the interaction of extremely high intensity laser light with the target plasma. To better understand laser-plasma interactions, a new class of targets was designed to study long scale-length plasmas (many hundred times the laser wavelength) by measurement of the temperature and density of the plasma as a function of time. The specifications for the target called for a freestanding hydrocarbon polymer (CH) film with a sharply defined spot (microspot) in the center seeded with either silicon or sulfur. The target film was fabricated using a three-step procedure which consisted of deposition of the hydrocarbon film, definition of the microspot, and then deposition of a seeded spot through a mask. In the final assembly step, the film containing the microspot was mounted over a 1.5 mm diam hole in a support. The support was either a plastic ring or a copper foil electroplated with 3 μm of gold. The fabrication of this type of target is described

SpotCaliper: fast wavelet-based spot detection with accurate size estimation.

Science.gov (United States)

Püspöki, Zsuzsanna; Sage, Daniel; Ward, John Paul; Unser, Michael

2016-04-15

SpotCaliper is a novel wavelet-based image-analysis software providing a fast automatic detection scheme for circular patterns (spots), combined with the precise estimation of their size. It is implemented as an ImageJ plugin with a friendly user interface. The user is allowed to edit the results by modifying the measurements (in a semi-automated way), extract data for further analysis. The fine tuning of the detections includes the possibility of adjusting or removing the original detections, as well as adding further spots. The main advantage of the software is its ability to capture the size of spots in a fast and accurate way. http://bigwww.epfl.ch/algorithms/spotcaliper/ zsuzsanna.puspoki@epfl.ch Supplementary data are available at Bioinformatics online. © The Author 2015. Published by Oxford University Press. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.

Roth spots in pernicious anaemia

OpenAIRE

Macauley, Mavin; Nag, Satyajit

2011-01-01

Roth spots are white-centred retinal haemorrhages, previously thought to be pathognomonic for subacute bacterial endocarditis. A number of other conditions can be associated with Roth spots. In this case, the authors describe the association of Roth spots and pernicious anaemia. This association has been rarely described in the medical literature. Correct diagnosis and treatment with intramuscular vitamin B12 injections resulted in complete resolution of the anaemia and Roth spots. The author...

Study of Anti-Hydrogen and Plasma Physics 4.Observation of Antiproton Beams and Nonneutral Plasmas

CERN Document Server

Hori, Masaki; Fujiwara, Makoto; Kuroda, Naofumi

2004-01-01

Diagnostics of antiproton beams and nonneutral plasmas are described in this chapter. Parallel plate secondary electron emission detectors are used to non-destructively observe the beam position and intensity without loss. Plastic scintillation tracking detectors are useful in determining the position of annihilations of antiprotons in the trap. Three-dimensional imaging of antiprotons in a Penning trap is discussed. The unique capability of antimatter particle imaging has allowed the observation of the spatial distribution of particle loss in a trap. Radial loss is localized to small spots, strongly breaking the azimuthal symmetry expected for an ideal trap. By observing electrostatic eigen-modes of nonneutral plasmas trapped in the Multi-ring electrode trap, the non-destructive measurement of plasma parameters is performed.

Optimization of laser parameters to obtain high-energy, high-quality electron beams through laser-plasma acceleration

International Nuclear Information System (INIS)

Samant, Sushil Arun; Sarkar, Deepangkar; Krishnagopal, Srinivas; Upadhyay, Ajay K.; Jha, Pallavi

2010-01-01

The propagation of an intense (a 0 =3), short-pulse (L∼λ p ) laser through a homogeneous plasma has been investigated. Using two-dimensional simulations for a 0 =3, the pulse-length and spot-size at three different plasma densities were optimized in order to get a better quality beam in laser wakefield accelerator. The study reveals that with increasing pulse-length the acceleration increases, but after a certain pulse-length (L>0.23λ p ) the emittance blows-up unacceptably. For spot-sizes less than that given by k p0 r s =2√(a 0 ), trapping is poor or nonexistent, and the optimal spot-size is larger. The deviation of the optimal spot-size from this formula increases as the density decreases. The efficacy of these two-dimensional simulations has been validated by running three-dimensional simulations at the highest density. It has been shown that good quality GeV-class beams can be obtained at plasma densities of ∼10 18 cm -3 . The quality of the beam can be substantially improved by selecting only the high-energy peak; in this fashion an energy-spread of better than 1% and a current in tens of kA can be achieved, which are important for applications such as free-electron lasers.

Variable-spot ion beam figuring

International Nuclear Information System (INIS)

Wu, Lixiang; Qiu, Keqiang; Fu, Shaojun

2016-01-01

This paper introduces a new scheme of ion beam figuring (IBF), or rather variable-spot IBF, which is conducted at a constant scanning velocity with variable-spot ion beam collimated by a variable diaphragm. It aims at improving the reachability and adaptation of the figuring process within the limits of machine dynamics by varying the ion beam spot size instead of the scanning velocity. In contrast to the dwell time algorithm in the conventional IBF, the variable-spot IBF adopts a new algorithm, which consists of the scan path programming and the trajectory optimization using pattern search. In this algorithm, instead of the dwell time, a new concept, integral etching time, is proposed to interpret the process of variable-spot IBF. We conducted simulations to verify its feasibility and practicality. The simulation results indicate the variable-spot IBF is a promising alternative to the conventional approach.

Numerical optimisation in spot detector design

NARCIS (Netherlands)

van der Heijden, Ferdinand; Apperloo, W.; Spreeuwers, Lieuwe Jan

1997-01-01

Spots are image details resulting from objects, the projections of which are so small that the inner structure of these objects cannot be resolved from their image. Spot detectors are image operators aiming at the detection and localisation of spots in the image. Most spot detectors can be tuned

Material influence on hot spot distribution in the nanoparticle heterodimer on film

Science.gov (United States)

Chen, Fang; Huang, Yingzhou; Wei, Hua; Wang, Shuxia; Zeng, Xiping; Cao, Wenbin; Wen, Weijia

2018-04-01

The metal nanoparticle aggregated on film, as an effective plasma enhancement pathway, has been widely used in various surface plasmon-related fields. In this study, the hot spots on the metal nanoparticle dimer composed of different materials (Agsbnd Au, Agsbnd Pd, and Agsbnd Cu) on metal (Au) film were investigated with finite element method. Based on the results, the hot spot distribution affected by the material can be confirmed by the electric field distribution of the metal nanoparticle dimer on the film. The aggregation effects of Au and Ag nanoparticles in Ausbnd Ag dimer system are not significant. However, for the Pdsbnd Ag dimer system, the hot spot aggregation effect is slightly larger than that of the Pd nanoparticle under the Ag nanoparticle. Besides, the non-uniform hot spots would bring about the light focusing phenomenon that the light intensity under Ag nanoparticle is almost 100 times greater than that under Cu nanoparticle in Agsbnd Cu dimer system. These results were further confirmed by the surface charge distribution, and analyzed based on the plasmonic hybridization theory. The data about the nanoparticle dimer on the dielectric (Si) film demonstrate the importance of induced image charges on the film surface in such a light focusing phenomenon. Our findings can enhance the understanding of the surface plasmon coupling in different materials, which may have great application prospects in surface plasmon-related fields, such as SERS, plasmonic enhanced solar cell, and plasmonic sensoring, etc.

9 CFR 149.4 - Spot audit.

Science.gov (United States)

2010-01-01

... 9 Animals and Animal Products 1 2010-01-01 2010-01-01 false Spot audit. 149.4 Section 149.4... LIVESTOCK IMPROVEMENT VOLUNTARY TRICHINAE CERTIFICATION PROGRAM § 149.4 Spot audit. (a) In addition to regularly scheduled site audits, certified production sites will be subject to spot audits. (1) Random spot...

Metallomic study on plasma samples from Nile tilapia using SR-XRF and GFAAS after separation by 2D PAGE: Initial results

International Nuclear Information System (INIS)

Santos, F.A.; Lima, P.M.; Neves, R.C.F.; Moraes, P.M.; Castro, G.R.; Padilha, P.M.; Perez, C.A.; Silva, M.O.A.; Arruda, M.A.Z.

2011-01-01

An investigation was made on plasma samples obtained after protein separation. The proteome of the plasma of Nile tilapia (Oreochromis niloticus) was separated by 2D PAGE, and manganese and zinc in protein spots was qualitatively and quantitatively determined by synchrotron radiation X-ray fluorescence (SR-XRF) and graphite furnace atomic absorption spectrometry (GFAAS). Manganese and zinc are present in four and six plasma protein spots, respectively. These ions are bound to proteins with molecular weights ranging from 19 to 70 kDa and with isoelectric point (pI) ranging from 4.7 to 6.3. The concentrations of manganese and zinc bound to these proteins as determined by GFAAS following acid digestion of the spots range from 0.8 to 2.6 mg of manganese, and from 1.0 to 6.3 mg of zinc, respectively, per g of protein. (author)

Spot formation of radiation particles by electrochemical etching

International Nuclear Information System (INIS)

Nozaki, Tetsuya

1999-01-01

An electrochemical etching (ECE) spot formation from the top of chemical etching (CE) spot was confirmed by a series of experiments. One of polycarbonate (Iupilon) could not make the spot, because ECE spot had grown up before the microscope confirming the CE spot. Clear CEC spots by α-ray and neutron were found on Harzlas and Baryotrak, both improvements of CR-39. Under the same etching conditions, the growth of ECE spot on Harzlas was more rapid than Baryotrak, but both spots were almost the same. All CE spot by α-ray produced the CEC spots, but a part of CE circle spot by neutron formed them. (S.Y.)

Laser treatment of plasma sprayed HA coatings

NARCIS (Netherlands)

Khor, KA; Vreeling, A; Dong, ZL; Cheang, P

1999-01-01

Laser treatment was conducted on plasma sprayed hydroxyapatite (HA) coatings using a Nd-YAG pulse laser. Various laser parameters were investigated. The results showed that the HA surface melted when an energy level of greater than or equal to 2 J and a spot size of 2 mm was employed during

Hydrodynamic optical-field-ionized plasma channels

Science.gov (United States)

Shalloo, R. J.; Arran, C.; Corner, L.; Holloway, J.; Jonnerby, J.; Walczak, R.; Milchberg, H. M.; Hooker, S. M.

2018-05-01

We present experiments and numerical simulations which demonstrate that fully ionized, low-density plasma channels could be formed by hydrodynamic expansion of plasma columns produced by optical field ionization. Simulations of the hydrodynamic expansion of plasma columns formed in hydrogen by an axicon lens show the generation of 200 mm long plasma channels with axial densities of order ne(0 ) =1 ×1017cm-3 and lowest-order modes of spot size WM≈40 μ m . These simulations show that the laser energy required to generate the channels is modest: of order 1 mJ per centimeter of channel. The simulations are confirmed by experiments with a spherical lens which show the formation of short plasma channels with 1.5 ×1017cm-3≲ne(0 ) ≲1 ×1018cm-3 and 61 μ m ≳WM≳33 μ m . Low-density plasma channels of this type would appear to be well suited as multi-GeV laser-plasma accelerator stages capable of long-term operation at high pulse repetition rates.

Managing emerging threats to spotted owls

Science.gov (United States)

Ho Yi Wan; Joseph L. Ganey; Christina D. Vojta; Samuel A. Cushman

2018-01-01

The 3 spotted owl (Strix occidentalis) subspecies in North America (i.e., northern spotted owl [S. o. caurina], California spotted owl [S. o. occidentalis], Mexican spotted owl [S. o. lucida]) have all experienced population declines over the past century due to habitat loss and fragmentation from logging. Now, the emerging influences of climate change, high-severity...

Computational Prediction of Hot Spot Residues

Science.gov (United States)

Morrow, John Kenneth; Zhang, Shuxing

2013-01-01

Most biological processes involve multiple proteins interacting with each other. It has been recently discovered that certain residues in these protein-protein interactions, which are called hot spots, contribute more significantly to binding affinity than others. Hot spot residues have unique and diverse energetic properties that make them challenging yet important targets in the modulation of protein-protein complexes. Design of therapeutic agents that interact with hot spot residues has proven to be a valid methodology in disrupting unwanted protein-protein interactions. Using biological methods to determine which residues are hot spots can be costly and time consuming. Recent advances in computational approaches to predict hot spots have incorporated a myriad of features, and have shown increasing predictive successes. Here we review the state of knowledge around protein-protein interactions, hot spots, and give an overview of multiple in silico prediction techniques of hot spot residues. PMID:22316154

Bulk hydrodynamic stability and turbulent saturation in compressing hot spots

Science.gov (United States)

Davidovits, Seth; Fisch, Nathaniel J.

2018-04-01

For hot spots compressed at constant velocity, we give a hydrodynamic stability criterion that describes the expected energy behavior of non-radial hydrodynamic motion for different classes of trajectories (in ρR — T space). For a given compression velocity, this criterion depends on ρR, T, and d T /d (ρR ) (the trajectory slope) and applies point-wise so that the expected behavior can be determined instantaneously along the trajectory. Among the classes of trajectories are those where the hydromotion is guaranteed to decrease and those where the hydromotion is bounded by a saturated value. We calculate this saturated value and find the compression velocities for which hydromotion may be a substantial fraction of hot-spot energy at burn time. The Lindl (Phys. Plasmas 2, 3933 (1995)] "attractor" trajectory is shown to experience non-radial hydrodynamic energy that grows towards this saturated state. Comparing the saturation value with the available detailed 3D simulation results, we find that the fluctuating velocities in these simulations reach substantial fractions of the saturated value.

Poisson Spot with Magnetic Levitation

Science.gov (United States)

Hoover, Matthew; Everhart, Michael; D'Arruda, Jose

2010-01-01

In this paper we describe a unique method for obtaining the famous Poisson spot without adding obstacles to the light path, which could interfere with the effect. A Poisson spot is the interference effect from parallel rays of light diffracting around a solid spherical object, creating a bright spot in the center of the shadow.

Time Resolved X-Ray Spot Size Diagnostic

CERN Document Server

Richardson, Roger; Falabella, Steven; Guethlein, Gary; Raymond, Brett; Weir, John

2005-01-01

A diagnostic was developed for the determination of temporal history of an X-ray spot. A pair of thin (0.5 mm) slits image the x-ray spot to a fast scintillator which is coupled to a fast detector, thus sampling a slice of the X-Ray spot. Two other scintillator/detectors are used to determine the position of the spot and total forward dose. The slit signal is normalized to the dose and the resulting signal is analyzed to get the spot size. The position information is used to compensate for small changes due to spot motion and misalignment. The time resolution of the diagnostic is about 1 ns and measures spots from 0.5 mm to over 3 mm. The theory and equations used to calculate spot size and position are presented, as well as data. The calculations assume a symmetric, Gaussian spot. The spot data is generated by the ETA II accelerator, a 2kA, 5.5 MeV, 60ns electron beam focused on a Tantalum target. The spot generated is typically about 1 mm FWHM. Comparisons are made to an X-ray pinhole camera which images th...

Plasma enhanced RF power deposition on ICRF antennas in Tore Supra

International Nuclear Information System (INIS)

Goulding, R.H.; Harris, J.H.; Carter, M.D.; Hoffman, D.J.; Hogan, J.T.; Ryan, P.M.; Beaumont, B.; Bremond, S.; Hutter, T.

1997-01-01

The dual-strap Tore Supra ICRF antennas have been very successful in coupling high power fluxes > 16 MW/m2 to the plasma. In many cases it has been found that the power is limited not by the voltages and currents that can be sustained on antenna components, but rather by localized increases in antenna surface temperatures which are correlated with increased impurity levels. Hot spots have been observed using an IR imaging system with peak temperatures as high as 1,100 C after 2 s, and as little as 1.5 MW power coupled from a single launcher. The maximum temperature observed is highly dependent on antenna phasing, and is lowest with dipole (π) phasing of the relative antenna currents. Both toroidal and poloidal asymmetries in hot spot distribution have been observed, and interestingly, the toroidal asymmetry has been found to vary when the phase is changed from +π/2 to -π/2. Significant differences in the temperature profiles have been seen on the two types of Faraday shield in use, which appears to be related to the fact that one type has a recessed center septum between straps while the other does not. In some cases, the peak temperature has been observed to increase as the antenna/plasma gap is increased, while the peak remains in the same location. This behavior suggests that voltages generated by currents flowing in the Faraday shield structure itself may play a role in generating potentials responsible for the hot spots, in addition to rf fields in the plasma. In this paper data on antenna surface heating and loading data as a function of plasma density, antenna/plasma gap, and phasing will be presented. Calculations from the RANT3D electromagnetic code together with bench measurements of electric fields near the antenna surface will also be shown

Statistical hot spot analysis of reactor cores

International Nuclear Information System (INIS)

Schaefer, H.

1974-05-01

This report is an introduction into statistical hot spot analysis. After the definition of the term 'hot spot' a statistical analysis is outlined. The mathematical method is presented, especially the formula concerning the probability of no hot spots in a reactor core is evaluated. A discussion with the boundary conditions of a statistical hot spot analysis is given (technological limits, nominal situation, uncertainties). The application of the hot spot analysis to the linear power of pellets and the temperature rise in cooling channels is demonstrated with respect to the test zone of KNK II. Basic values, such as probability of no hot spots, hot spot potential, expected hot spot diagram and cumulative distribution function of hot spots, are discussed. It is shown, that the risk of hot channels can be dispersed equally over all subassemblies by an adequate choice of the nominal temperature distribution in the core

Characteristics of cold atmospheric plasma source based on low-current pulsed discharge with coaxial electrodes

Science.gov (United States)

Bureyev, O. A.; Surkov, Yu S.; Spirina, A. V.

2017-05-01

This work investigates the characteristics of the gas discharge system used to create an atmospheric pressure plasma flow. The plasma jet design with a cylindrical graphite cathode and an anode rod located on the axis of the system allows to realize regularly reproducible spark breakdowns mode with a frequency ∼ 5 kHz and a duration ∼ 40 μs. The device generates a cold atmospheric plasma flame with 1 cm in diameter in the flow of various plasma forming gases including nitrogen and air at about 100 mA average discharge current. In the described construction the cathode spots of individual spark channels randomly move along the inner surface of the graphite electrode creating the secondary plasma stream time-average distributed throughout the whole exit aperture area after the decay of numerous filamentary discharge channels. The results of the spectral diagnostics of plasma in the discharge gap and in the stream coming out of the source are presented. Despite the low temperature of atoms and molecules in plasma stream the cathode spots operation with temperature of ∼ 4000 °C at a graphite electrode inside a discharge system enables to saturate the plasma by CN-radicals and atomic carbon in the case of using nitrogen as the working gas.

Hot Spot Removal System: System description

Energy Technology Data Exchange (ETDEWEB)

NONE

1997-09-01

Hazardous wastes contaminated with radionuclides, chemicals, and explosives exist across the Department of Energy complex and need to be remediated due to environmental concerns. Currently, an opportunity is being developed to dramatically reduce remediation costs and to assist in the acceleration of schedules associated with these wastes by deploying a Hot Spot Removal System. Removing the hot spot from the waste site will remove risk driver(s) and enable another, more cost effective process/option/remedial alternative (i.e., capping) to be applied to the remainder of the site. The Hot Spot Removal System consists of a suite of technologies that will be utilized to locate and remove source terms. Components of the system can also be used in a variety of other cleanup activities. This Hot Spot Removal System Description document presents technologies that were considered for possible inclusion in the Hot Spot Removal System, technologies made available to the Hot Spot Removal System, industrial interest in the Hot Spot Removal System`s subsystems, the schedule required for the Hot Spot Removal System, the evaluation of the relevant technologies, and the recommendations for equipment and technologies as stated in the Plan section.

Hot Spot Removal System: System description

International Nuclear Information System (INIS)

1997-09-01

Hazardous wastes contaminated with radionuclides, chemicals, and explosives exist across the Department of Energy complex and need to be remediated due to environmental concerns. Currently, an opportunity is being developed to dramatically reduce remediation costs and to assist in the acceleration of schedules associated with these wastes by deploying a Hot Spot Removal System. Removing the hot spot from the waste site will remove risk driver(s) and enable another, more cost effective process/option/remedial alternative (i.e., capping) to be applied to the remainder of the site. The Hot Spot Removal System consists of a suite of technologies that will be utilized to locate and remove source terms. Components of the system can also be used in a variety of other cleanup activities. This Hot Spot Removal System Description document presents technologies that were considered for possible inclusion in the Hot Spot Removal System, technologies made available to the Hot Spot Removal System, industrial interest in the Hot Spot Removal System''s subsystems, the schedule required for the Hot Spot Removal System, the evaluation of the relevant technologies, and the recommendations for equipment and technologies as stated in the Plan section

Initiation of arcing on tungsten surface exposed to steady state He plasmas

Science.gov (United States)

Kajita, Shin; Noiri, Yasuyuki; Ohno, Noriyasu

2015-09-01

Arcing was initiated in steady state helium plasmas by negatively biasing a tungsten electrode to around -500 V. On the tungsten electrode, nanostructures were grown by the plasma irradiation. In this study, we characterized the property of the initiated arcing by measuring the temporal evolutions of the electrode potential and the arc current. The ignition frequency and duration of arcing were presented from the potential measurements; the arc duration was in the range of changing the biasing voltage. The behavior of arc spots was observed with a fast framing camera. It was shown that the spots split frequently, and sometimes, they run on the surface independently. From the fluctuation of the arc current, the fractal feature of arcing was revealed.

Rocky Mountain Spotted Fever

Science.gov (United States)

... with facebook share with twitter share with linkedin Rocky Mountain Spotted Fever Credit: CDC A male cayenne tick, Amblyomma cajennense, ... and New Mexico. Why Is the Study of Rocky Mountain Spotted Fever a Priority for NIAID? Tickborne diseases are becoming ...

Retinol analysis in dried blood spots by HPLC.

Science.gov (United States)

Craft, N E; Haitema, T; Brindle, L K; Yamini, S; Humphrey, J H; West, K P

2000-04-01

There are many advantages to measuring vitamin A in dried blood spots (DBS) from a finger prick as compared to plasma collected by venipuncture. The advantages include easier collection, transport and storage; accessibility to younger and more remote populations; and decreased risk of disease transmission. We describe a method for the extraction of retinol from DBS for analysis by HPLC and initial comparison to plasma retinol. The effects of various buffers, detergents, antioxidants and chelators were evaluated to establish the most effective approach to elute the retinol: retinol binding protein (holo-RBP) complex from the blood collection cards. The process involves ultrasonic agitation to elute holo-RBP into a phosphate buffer containing an antioxidant and metal chelator. The holo-RBP complex was denatured by the addition of ethanol containing additional antioxidants permitting the extraction of free retinol into hexane. Following solvent evaporation, the extract was dissolved in methanol for HPLC analysis. The initial measured retinol levels in freshly collected DBS declined for 6-10 d whether stored at 25, 4 or -20 degrees C, but remained consistent thereafter (homeostatic). By incorporating a "recovery/volume adjustment" factor, measured retinol values in homeostatic DBS were adjusted to the equivalent of plasma retinol. For 17 normal adults, the correlation coefficient was 0.90 between plasma retinol and adjusted DBS retinol in samples that had been stored at -70 degrees C for < 9 mo. The use of this new sample matrix for vitamin A assessment will allow access to previously unavailable populations.

Laser Pyrometer For Spot Temperature Measurements

Science.gov (United States)

Elleman, D. D.; Allen, J. L.; Lee, M. C.

1988-01-01

Laser pyrometer makes temperature map by scanning measuring spot across target. Scanning laser pyrometer passively measures radiation emitted by scanned spot on target and calibrated by similar passive measurement on blackbody of known temperature. Laser beam turned on for active measurements of reflectances of target spot and reflectance standard. From measurements, temperature of target spot inferred. Pyrometer useful for non-contact measurement of temperature distributions in processing of materials.

Resistance Spot Welding of dissimilar Steels

Directory of Open Access Journals (Sweden)

Ladislav Kolařík

2012-01-01

Full Text Available This paper presents an analysis of the properties of resistance spot welds between low carbon steel and austenitic CrNi stainless steel. The thickness of the welded dissimilar materials was 2 mm. A DeltaSpot welding gun with a process tape was used for welding the dissimilar steels. Resistance spot welds were produced with various welding parameters (welding currents ranging from 7 to 8 kA. Light microscopy, microhardness measurements across the welded joints, and EDX analysis were used to evaluate the quality of the resistance spot welds. The results confirm the applicability of DeltaSpot welding for this combination of materials.

Stimulated Brillouin scattering reflectivity in the case of a spatially smoothed laser beam interacting with an inhomogeneous plasma

International Nuclear Information System (INIS)

Tikhonchuk, V.T.; Mounaix, P.; Pesme, D.

1997-01-01

The stimulated Brillouin scattering (SBS) instability is investigated theoretically in the case of a spatially smoothed laser beam interacting with an inhomogeneous plasma in the regime of strong ion acoustic damping. The domain of parameters being considered corresponds to most of the present day experiments carried out with nanosecond laser pulses interacting with preformed plasmas: the characteristic length for convective amplification is assumed to be much shorter than the longitudinal correlation length of the laser field. The SBS reflectivity of one individual hot spot is analytically computed taking into account thermal noise emission and pump depletion within the hot spot. The SBS reflectivity of the whole beam is then obtained by summing up the individual hot spot reflectivities in accordance with their statistical distribution. copyright 1997 American Institute of Physics

Protein expression profiling by antibody array analysis with use of dried blood spot samples on filter paper.

Science.gov (United States)

Jiang, Weidong; Mao, Ying Qing; Huang, Ruochun; Duan, Chaohui; Xi, Yun; Yang, Kai; Huang, Ruo-Pan

2014-01-31

Dried blood spot samples (DBSS) on filter paper offer several advantages compared to conventional serum/plasma samples: they do not require any phlebotomy or separation of blood by centrifugation; they are less invasive; they allow sample stability and shipment at room temperature; and they pose a negligible risk of infection with blood-borne viruses, such as HIV, HBV and HCV, to those who handle them. Therefore dried blood spot samples (DBSS) on filter paper can be a quick, convenient and inexpensive means of obtaining blood samples for biomarker discovery, disease screening, diagnosis and treatment monitoring in non-hospitalized, public health settings. In this study, we investigated for the first time the potential application of dried blood spot samples (DBSS) in protein expression profiling using antibody array technology. First, optimal conditions for array assay performance using dried blood spot samples (DBSS) was established, including sample elution buffer, elution time, elution temperature and assay blocking buffer. Second, we analyzed dried blood spot samples (DBSS) using three distinct antibody array platforms, including sandwich-based antibody arrays, quantitative antibody arrays and biotin-label-based antibody arrays. In comparison with paired serum samples, detection of circulating proteins in dried blood spot samples (DBSS) correlated well for both low- and high-abundance proteins on all three antibody array platforms. In conclusion, our study strongly indicates the novel application of multiplex antibody array platforms to analyze dried blood spot samples (DBSS) on filter paper represents a viable, cost-effective method for protein profiling, biomarker discovery and disease screening in a large, population-based survey. Copyright © 2013 Elsevier B.V. All rights reserved.

On the relationships between electron spot size, focal spot size, and virtual source position in Monte Carlo simulations

International Nuclear Information System (INIS)

Sterpin, E.; Chen, Y.; Lu, W.; Mackie, T. R.; Olivera, G. H.; Vynckier, S.

2011-01-01

Purpose: Every year, new radiotherapy techniques including stereotactic radiosurgery using linear accelerators give rise to new applications of Monte Carlo (MC) modeling. Accurate modeling requires knowing the size of the electron spot, one of the few parameters to tune in MC models. The resolution of integrated megavoltage imaging systems, such as the tomotherapy system, strongly depends on the photon spot size which is closely related to the electron spot. The aim of this article is to clarify the relationship between the electron spot size and the photon spot size (i.e., the focal spot size) for typical incident electron beam energies and target thicknesses. Methods: Three electron energies (3, 5.5, and 18 MeV), four electron spot sizes (FWHM=0, 0.5, 1, and 1.5 mm), and two tungsten target thicknesses (0.15 and 1 cm) were considered. The formation of the photon beam within the target was analyzed through electron energy deposition with depth, as well as photon production at several phase-space planes placed perpendicular to the beam axis, where only photons recorded for the first time were accounted for. Photon production was considered for ''newborn'' photons intersecting a 45x45 cm 2 plane at the isocenter (85 cm from source). Finally, virtual source position and ''effective'' focal spot size were computed by backprojecting all the photons from the bottom of the target intersecting a 45x45 cm 2 plane. The virtual source position and focal spot size were estimated at the plane position where the latter is minimal. Results: In the relevant case of considering only photons intersecting the 45x45 cm 2 plane, the results unambiguously showed that the effective photon spot is created within the first 0.25 mm of the target and that electron and focal spots may be assumed to be equal within 3-4%. Conclusions: In a good approximation photon spot size equals electron spot size for high energy X-ray treatments delivered by linear accelerators.

Solar 'hot spots' are still hot

Science.gov (United States)

Bai, Taeil

1990-01-01

Longitude distributions of solar flares are not random but show evidence for active zones (or hot spots) where flares are concentrated. According to a previous study, two hot spots in the northern hemisphere, which rotate with a synodic period of about 26.72 days, produced the majority of major flares, during solar cycles 20 and 21. The more prominent of these two hot spots is found to be still active during the rising part of cycle 22, producing the majority of northern hemisphere major flares. The synodic rotation period of this hot spot is 26.727 + or - 0.007 days. There is also evidence for hot spots in the southern hemisphere. Two hot spots separated by 180 deg are found to rotate with a period of 29.407 days, with one of them having persisted in the same locations during cycles 19-22 and the other, during cycles 20-22.

Rapid DNA extraction from dried blood spots on filter paper: potential applications in biobanking.

Science.gov (United States)

Choi, Eun-Hye; Lee, Sang Kwang; Ihm, Chunhwa; Sohn, Young-Hak

2014-12-01

Dried blood spot (DBS) technology is a microsampling alternative to traditional plasma or serum sampling for pharmaco- or toxicokinetic evaluation. DBS technology has been applied to diagnostic screening in drug discovery, nonclinical, and clinical settings. We have developed an improved elution protocol involving boiling of blood spots dried on Whatman filter paper. The purpose of this study was to compare the quality, purity, and quantity of DNA isolated from frozen blood samples and DBSs. We optimized a method for extraction and estimation of DNA from blood spots dried on filter paper (3-mm FTA card). A single DBS containing 40 μL blood was used. DNA was efficiently extracted in phosphate-buffered saline (PBS) or Tris-EDTA (TE) buffer by incubation at 37°C overnight. DNA was stable in DBSs that were stored at room temperature or frozen. The housekeeping genes GAPDH and beta-actin were used as positive standards for polymerase chain reaction (PCR) validation of general diagnostic screening. Our simple and convenient DBS storage and extraction methods are suitable for diagnostic screening by using very small volumes of blood collected on filter paper, and can be used in biobanks for blood sample storage.

Arc cathode spots

International Nuclear Information System (INIS)

Schrade, H.O.

1989-01-01

Arc spots are usually highly unstable and jump statistically over the cathode surface. In a magnetic field parallel to the surface, preferably they move in the retrograde direction; i.e., opposite to the Lorentzian rule. If the field is inclined with respect to the surface, the spots drift away at a certain angle with respect to the proper retrograde direction (Robson drift motion). These well-known phenomena are explained by one stability theory

7 CFR 28.413 - Middling Light Spotted Color.

Science.gov (United States)

2010-01-01

... 7 Agriculture 2 2010-01-01 2010-01-01 false Middling Light Spotted Color. 28.413 Section 28.413... Spotted Color. Middling Light Spotted Color is color which in spot or color, or both, is between Middling Color and Middling Spotted Color. ...

Compressing and focusing a short laser pulse by a thin plasma lens

International Nuclear Information System (INIS)

Ren, C.; Duda, B. J.; Hemker, R. G.; Mori, W. B.; Katsouleas, T.; Antonsen, T. M.; Mora, P.

2001-01-01

We consider the possibility of using a thin plasma slab as an optical element to both focus and compress an intense laser pulse. By thin we mean that the focal length is larger than the lens thickness. We derive analytic formulas for the spot size and pulse length evolution of a short laser pulse propagating through a thin uniform plasma lens. The formulas are compared to simulation results from two types of particle-in-cell code. The simulations give a greater final spot size and a shorter focal length than the analytic formulas. The difference arises from spherical aberrations in the lens which lead to the generation of higher-order vacuum Gaussian modes. The simulations also show that Raman side scattering can develop. A thin lens experiment could provide unequivocal evidence of relativistic self-focusing

Solar hot spots are still hot

International Nuclear Information System (INIS)

Bai, T.

1990-01-01

Longitude distributions of solar flares are not random but show evidence for active zones (or hot spots) where flares are concentrated. According to a previous study, two hot spots in the northern hemisphere, which rotate with a synodic period of about 26.72 days, produced the majority of major flares, during solar cycles 20 and 21. The more prominent of these two hot spots is found to be still active during the rising part of cycle 22, producing the majority of northern hemisphere major flares. The synodic rotation period of this hot spot is 26.727 + or - 0.007 days. There is also evidence for hot spots in the southern hemisphere. Two hot spots separated by 180 deg are found to rotate with a period of 29.407 days, with one of them having persisted in the same locations during cycles 19-22 and the other, during cycles 20-22. 14 refs

7 CFR 28.423 - Middling Spotted Color.

Science.gov (United States)

2010-01-01

... 7 Agriculture 2 2010-01-01 2010-01-01 false Middling Spotted Color. 28.423 Section 28.423... REGULATIONS COTTON CLASSING, TESTING, AND STANDARDS Standards Spotted Cotton § 28.423 Middling Spotted Color. Middling Spotted Color is color which is within the range represented by a set of samples in the custody of...

Brillouin scatter in laser-produced plasmas

International Nuclear Information System (INIS)

Phillion, D.W.; Kruer, W.L.; Rupert, V.C.

1977-01-01

The absorption of intense laser light is found to be reduced when targets are irradiated by 1.06 μm light with long pulse widths (150-400 psec) and large focal spots (100-250 μm). Estimates of Brillouin scatter which account for the finite heat capacity of the underdense plasma predict this reduction. Spectra of the back reflected light show red shifts indicative of Brillouin scattering

Advantages and Challenges of Dried Blood Spot Analysis by Mass Spectrometry Across the Total Testing Process

Science.gov (United States)

Zakaria, Rosita; Allen, Katrina J.; Koplin, Jennifer J.; Roche, Peter

2016-01-01

Introduction Through the introduction of advanced analytical techniques and improved throughput, the scope of dried blood spot testing utilising mass spectrometric methods, has broadly expanded. Clinicians and researchers have become very enthusiastic about the potential applications of dried blood spot based mass spectrometric applications. Analysts on the other hand face challenges of sensitivity, reproducibility and overall accuracy of dried blood spot quantification. In this review, we aim to bring together these two facets to discuss the advantages and current challenges of non-newborn screening applications of dried blood spot quantification by mass spectrometry. Methods To address these aims we performed a key word search of the PubMed and MEDLINE online databases in conjunction with individual manual searches to gather information. Keywords for the initial search included; “blood spot” and “mass spectrometry”; while excluding “newborn”; and “neonate”. In addition, databases were restricted to English language and human specific. There was no time period limit applied. Results As a result of these selection criteria, 194 references were identified for review. For presentation, this information is divided into: 1) clinical applications; and 2) analytical considerations across the total testing process; being pre-analytical, analytical and post-analytical considerations. Conclusions DBS analysis using MS applications is now broadly applied, with drug monitoring for both therapeutic and toxicological analysis being the most extensively reported. Several parameters can affect the accuracy of DBS measurement and further bridge experiments are required to develop adjustment rules for comparability between dried blood spot measures and the equivalent serum/plasma values. Likewise, the establishment of independent reference intervals for dried blood spot sample matrix is required. PMID:28149263

Improved simulation method of automotive spot weld failure with an account of the mechanical properties of spot welds

Science.gov (United States)

Wu, H.; Meng, X. M.; Fang, R.; Huang, Y. F.; Zhan, S.

2017-12-01

In this paper, the microstructure and mechanical properties of spot weld were studied, the hardness of nugget and heat affected zone (HAZ) were also tested by metallographic microscope and microhardness tester. The strength of the spot weld with the different parts' area has been characterized. According to the experiments result, CAE model of spot weld with HAZ structure was established, and simulation results of different lap-shear CAE models were analyzed. The results show that the spot weld model which contained the HAZ has good performance and more suitable for engineering application in spot weld simulation.

Characterisation of Plasma Filled Rod Pinch electron beam diode operation

Science.gov (United States)

MacDonald, James; Bland, Simon; Chittenden, Jeremy

2016-10-01

The plasma filled rod pinch diode (aka PFRP) offers a small radiographic spot size and a high brightness source. It operates in a very similar to plasma opening switches and dense plasma focus devices - with a plasma prefill, supplied via a number of simple coaxial plasma guns, being snowploughed along a thin rod cathode, before detaching at the end. The aim of this study is to model the PFRP and understand the factors that affect its performance, potentially improving future output. Given the dependence on the PFRP on the prefill, we are making detailed measurements of the density (1015-1018 cm-3), velocity, ionisation and temperature of the plasma emitted from a plasma gun/set of plasma guns. This will then be used to provide initial conditions to the Gorgon 3D MHD code, and the dynamics of the entire rod pinch process studied.

TV spots' impact.

Science.gov (United States)

El-bakly, S

1994-09-01

The Information, Education and Communication (IEC) Center of the State Information Service was established in 1979 for the purpose of providing information to the people on the population issue. The Ministry of Information has accorded the State Information Service free TV and radio air time for family planning dramas and spots. In the early years information campaigns were organized to make people aware of the population problem by slogans, songs, and cartoons. Around 1984 misconceptions about family planning and contraceptives were attacked through a number of TV and radio spots. A few years later 21 spots on specific contraceptive methods were broadcast which were aired for three years over 3000 times. They were extremely successful. The impact of these TV spots was one of the major reasons why the contraceptive prevalence rate increased from 30% in 1984 to 38% in 1988 and 47% in 1992. Spots were also broadcast about the social implications of large families. The TV soap opera "And The Nile Flows On", with the family planning message interwoven into it, was very well received by the target audience. A program entitled "Wedding of the Month" features couples who know family planning well. The most successful radio program is a 15-20 minute long quiz show for residents of the villages where the Select Villages Project is being implemented. The State Information Service has 60 local information centers in the 26 governorates of Egypt that make plans for the family planning campaign. In 1992 the Minya Initiative, a family planning project was implemented in the Minya Governorate. As a result, the contraceptive prevalence rate rose from 22% to 30% over 18 months. A new project, the Select Village Project, was developed in 1993 that replicates the Minya Initiative on the village level in other governorates. This new project that was implemented in sixteen governorates.

Black-spot poison ivy.

Science.gov (United States)

Schram, Sarah E; Willey, Andrea; Lee, Peter K; Bohjanen, Kimberly A; Warshaw, Erin M

2008-01-01

In black-spot poison ivy dermatitis, a black lacquerlike substance forms on the skin when poison ivy resin is exposed to air. Although the Toxicodendron group of plants is estimated to be the most common cause of allergic contact dermatitis in the United States, black-spot poison ivy dermatitis is relatively rare.

Measurement of lower hybrid hot spots using a retarding field analyzer in Tore Supra

Czech Academy of Sciences Publication Activity Database

Gunn, J. P.; Petržílka, Václav; Ekedahl, A.; Fuchs, Vladimír; Gauthier, E.; Goniche, M.; Kočan, M.; Pascal, J.Y.; Saint Laurent, F.

390-391, č. 1 (2009), s. 904-906 ISSN 0022-3115. [International Conference on Plasma-Surface Interactions in Controlled Fusion Devices/18th./. Toledo, 26.05.2008-30.5.2008] R&D Projects: GA ČR GA202/07/0044 Institutional research plan: CEZ:AV0Z20430508 Keywords : Lower Hybrid * hot spots * ELECTRONS * POWER Subject RIV: BL - Plasma and Gas Discharge Physics Impact factor: 1.933, year: 2009 http://www.sciencedirect.com/science?_ob=ArticleURL&_udi=B6TXN-4VG7MW6-7&_user=6542793&_rdoc=1&_fmt=&_orig=search&_sort=d&_docanchor=&view=c&_acct=C000070123&_version=1&_urlVersion=0&_userid=6542793&md5=944ed4d95df86a149fa36439db6215db

Computational prediction of protein hot spot residues.

Science.gov (United States)

Morrow, John Kenneth; Zhang, Shuxing

2012-01-01

Most biological processes involve multiple proteins interacting with each other. It has been recently discovered that certain residues in these protein-protein interactions, which are called hot spots, contribute more significantly to binding affinity than others. Hot spot residues have unique and diverse energetic properties that make them challenging yet important targets in the modulation of protein-protein complexes. Design of therapeutic agents that interact with hot spot residues has proven to be a valid methodology in disrupting unwanted protein-protein interactions. Using biological methods to determine which residues are hot spots can be costly and time consuming. Recent advances in computational approaches to predict hot spots have incorporated a myriad of features, and have shown increasing predictive successes. Here we review the state of knowledge around protein-protein interactions, hot spots, and give an overview of multiple in silico prediction techniques of hot spot residues.

A partially ionized plasma modeling; Un modele de plasma partiellement ionise

Energy Technology Data Exchange (ETDEWEB)

Le Thanh, K.C.; Raviart, P.A

2003-07-01

We propose a model for the partially ionized plasma sheaths near the anode of an anodic spot electric arc where the cathode is considered as an electron emitter. A fluid description takes into account the heating and the ionization of the plasma induced by the electron beam. As physical hypothesis we assume that the condition of charge neutrality is valid. According that the electron mass can be neglected compared to the ion mass, we can assume that ions and atoms have the same velocity and the same temperature. Electrons and heavy particles are then regarded as two separate fluids coexisting in the plasma. Governing equations are then multi-fluid equations with relaxation correction to the local thermodynamic equilibrium (LTE) and heating by Joule effect. Equations are solved by an operator splitting procedure. That is we first discretize the homogeneous conservation laws (i.e. without source terms) by a finite volume method. The second step is to solve the ordinary differential system (i.e, governing equation without transport terms) with an implicit scheme. (authors)

7 CFR 1421.11 - Spot checks.

Science.gov (United States)

2010-01-01

... 7 Agriculture 10 2010-01-01 2010-01-01 false Spot checks. 1421.11 Section 1421.11 Agriculture... ASSISTANCE LOANS AND LOAN DEFICIENCY PAYMENTS FOR 2008 THROUGH 2012 General § 1421.11 Spot checks. (a) CCC... CCC access to the farm and storage facility as necessary to conduct collateral inspections, or “spot...

21 CFR 886.1435 - Maxwell spot.

Science.gov (United States)

2010-04-01

... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Maxwell spot. 886.1435 Section 886.1435 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES OPHTHALMIC DEVICES Diagnostic Devices § 886.1435 Maxwell spot. (a) Identification. A Maxwell spot is an AC...

Multiple solutions in the theory of direct current glow discharges: Effect of plasma chemistry and nonlocality, different plasma-producing gases, and 3D modelling

Energy Technology Data Exchange (ETDEWEB)

Almeida, P. G. C.; Benilov, M. S. [Departamento de Física, CCCEE, Universidade da Madeira, Largo do Município, 9000 Funchal (Portugal)

2013-10-15

The work is aimed at advancing the multiple steady-state solutions that have been found recently in the theory of direct current (DC) glow discharges. It is shown that an account of detailed plasma chemistry and non-locality of electron transport and kinetic coefficients results in an increase of the number of multiple solutions but does not change their pattern. Multiple solutions are shown to exist for discharges in argon and helium provided that discharge pressure is high enough. This result indicates that self-organization in DC glow microdischarges can be observed not only in xenon, which has been the case until recently, but also in other plasma-producing gases; a conclusion that has been confirmed by recent experiments. Existence of secondary bifurcations can explain why patterns of spots grouped in concentric rings, observed in the experiment, possess in many cases higher number of spots in outer rings than in inner ones.

Newborn screening blood spot analysis in the UK: influence of spot size, punch location and haematocrit.

Science.gov (United States)

Lawson, A J; Bernstone, L; Hall, S K

2016-03-01

In dried blood spot analysis, punch location and variations in applied sample volume and haematocrit can produce different measured concentrations of analytes. We investigated the magnitude of these effects in newborn screening in the UK. Heparinized blood spiked with thyroid stimulating hormone (TSH), phenylalanine, tyrosine, leucine, methionine, octanoyl carnitine (C8), and immunoreactive trypsinogen (IRT) was spotted onto filter paper: (i) at a constant haematocrit of 50% at various volumes, and (ii) at a range of haematocrits using a constant volume. Subpunches (3.2 mm) of the dried blood spots were then analysed. Compared with a central punch from a 50 µL blood spot with 50% haematocrit, 10 µL spots can have significantly lower measured concentrations of all analytes, with decreases of 15% or more observed for leucine, methionine, phenylalanine, and tyrosine. Punching at the edge of a spot can increase measured concentrations up to 35%. Higher haematocrit decreased measured TSH and C8 yet increased amino acids and IRT by 15% compared with 50% haematocrit. Lower haematocrits had the opposite effect, but only with higher concentrations of some analytes. Differences in blood spot size, haematocrit and punch location substantially affect measured concentrations for analytes used in the UK newborn screening programme, and this could affect false positive and negative rates. To minimize analytical bias, these variables should be controlled or adjusted for where possible. © The Author(s) 2015.

Alpha Heating and Burning Plasmas in Inertial Confinement Fusion.

Science.gov (United States)

Betti, R; Christopherson, A R; Spears, B K; Nora, R; Bose, A; Howard, J; Woo, K M; Edwards, M J; Sanz, J

2015-06-26

Estimating the level of alpha heating and determining the onset of the burning plasma regime is essential to finding the path towards thermonuclear ignition. In a burning plasma, the alpha heating exceeds the external input energy to the plasma. Using a simple model of the implosion, it is shown that a general relation can be derived, connecting the burning plasma regime to the yield enhancement due to alpha heating and to experimentally measurable parameters such as the Lawson ignition parameter. A general alpha-heating curve is found, independent of the target and suitable to assess the performance of all laser fusion experiments whether direct or indirect drive. The onset of the burning plasma regime inside the hot spot of current implosions on the National Ignition Facility requires a fusion yield of about 50 kJ.

Advances in spot curing technology

International Nuclear Information System (INIS)

Burga, R.

1999-01-01

A brief review of spot curing technology was presented. The process which a spot of energy of a specific wavelength bandwidth and irradiance is used to cause a coating, encapsulant or adhesive to change from a liquid to a solid state

Investigation of laser plasma instabilities using picosecond laser pulses

International Nuclear Information System (INIS)

Kline, J L; Montgomery, D S; Yin, L; Flippo, K A; Shimada, T; Johnson, R P; Rose, H A; Albright, B J; Hardin, R A

2008-01-01

A new short-pulse version of the single-hot-spot configuration has been implemented to enhance the performance of experiments to understand Stimulated Raman Scattering. The laser pulse length was reduced from ∼200 to ∼3 ps. The reduced pulse length improves the experiment by minimizing effects such as plasma hydrodynamic evolution and ponderomotive filamentation of the interaction beam. In addition, the shortened laser pulses allow full length 2D particle-in-cell simulations of the experiments. Using the improved single-hot-spot configuration, a series of experiments to investigate kλ D scaling of SRS has been performed. Details of the experimental setup and initial results will be presented

Exfoliation of the tungsten fibreform nanostructure by unipolar arcing in the LHD divertor plasma

Science.gov (United States)

Tokitani, M.; Kajita, S.; Masuzaki, S.; Hirahata, Y.; Ohno, N.; Tanabe, T.; LHD Experiment Group

2011-10-01

The tungsten nanostructure (W-fuzz) created in the linear divertor simulator (NAGDIS) was exposed to the Large Helical Device (LHD) divertor plasma for only 2 s (1 shot) to study exfoliation/erosion and microscopic modifications due to the high heat/particle loading under high magnetic field conditions. Very fine and randomly moved unipolar arc trails were clearly observed on about half of the W-fuzz area (6 × 10 mm2). The fuzzy surface was exfoliated by continuously moving arc spots even for the very short exposure time. This is the first observation of unipolar arcing and exfoliation of some areas of the W-fuzz structure itself in a large plasma confinement device with a high magnetic field. The typical width and depth of each arc trail were about 8 µm and 1 µm, respectively, and the arc spots moved randomly on the micrometre scale. The fractality of the arc trails was analysed using a box-counting method, and the fractal dimension (D) of the arc trails was estimated to be D ≈ 1.922. This value indicated that the arc spots moved in Brownian motion, and were scarcely influenced by the magnetic field. One should note that such a large scale exfoliation due to unipolar arcing may enhance the surface erosion of the tungsten armour and act as a serious impurity source for fusion plasmas.

Exfoliation of the tungsten fibreform nanostructure by unipolar arcing in the LHD divertor plasma

International Nuclear Information System (INIS)

Tokitani, M.; Masuzaki, S.; Kajita, S.; Hirahata, Y.; Ohno, N.; Tanabe, T.

2011-01-01

The tungsten nanostructure (W-fuzz) created in the linear divertor simulator (NAGDIS) was exposed to the Large Helical Device (LHD) divertor plasma for only 2 s (1 shot) to study exfoliation/erosion and microscopic modifications due to the high heat/particle loading under high magnetic field conditions. Very fine and randomly moved unipolar arc trails were clearly observed on about half of the W-fuzz area (6 x 10 mm 2 ). The fuzzy surface was exfoliated by continuously moving arc spots even for the very short exposure time. This is the first observation of unipolar arcing and exfoliation of some areas of the W-fuzz structure itself in a large plasma confinement device with a high magnetic field. The typical width and depth of each arc trail were about 8 μm and 1 μm, respectively, and the arc spots moved randomly on the micrometre scale. The fractality of the arc trails was analysed using a box-counting method, and the fractal dimension (D) of the arc trails was estimated to be D ∼ 1.922. This value indicated that the arc spots moved in Brownian motion, and were scarcely influenced by the magnetic field. One should note that such a large scale exfoliation due to unipolar arcing may enhance the surface erosion of the tungsten armour and act as a serious impurity source for fusion plasmas. (letter)

Eksistensi DPS dalam Memoderasi Pengaruh Pembiayaan, Kinerja Keuangan dan Pengungkapan CSR pada Bank Umum Syariah di Indonesia

Directory of Open Access Journals (Sweden)

Ely Masykuroh

2012-05-01

Full Text Available The research was conducted as motivated by previous research related to Corporate Social Responsibility (CSR. Previous researchfound mixed results seen from factors that influence the level of disclosure of CSR such as size, leverage, profitability (financial performance, board composition and ownership structure. The results of these findings is the space to do the test again to make the development or change in methodology. While the results of related research in Islamic banks are financing gap (lack. To the researchers intend to analyze whether the financial effect on the financial performance of Islamic banks as well as the extent to which the existence of the Syaria Supervisory Board moderating relationship. After that study also examines whether financial performance (profitability affect the disclosure of CSR by entering the variable composition of the Council to moderate the relationship. Methodology that differentiates it from previous research, the supervisory board who previously used as a moderating variable became an independent variable by using Islamicity Disclosure Index and analysis tool using the Moderation Regression Analysis. The results showed no significant effect of financing, profitability and CSR Disclosure, and the role of DPS was also moderate the influence of the relationship between financing and profitability, but the Board of Commissioners did not moderate the influence of the relationship between profitability and CSR disclosure

The fractal nature of vacuum arc cathode spots

International Nuclear Information System (INIS)

Anders, Andre

2005-01-01

Cathode spot phenomena show many features of fractals, for example self-similar patterns in the emitted light and arc erosion traces. Although there have been hints on the fractal nature of cathode spots in the literature, the fractal approach to spot interpretation is underutilized. In this work, a brief review of spot properties is given, touching the differences between spot type 1 (on cathodes surfaces with dielectric layers) and spot type 2 (on metallic, clean surfaces) as well as the known spot fragment or cell structure. The basic properties of self-similarity, power laws, random colored noise, and fractals are introduced. Several points of evidence for the fractal nature of spots are provided. Specifically power laws are identified as signature of fractal properties, such as spectral power of noisy arc parameters (ion current, arc voltage, etc) obtained by fast Fourier transform. It is shown that fractal properties can be observed down to the cutoff by measurement resolution or occurrence of elementary steps in physical processes. Random walk models of cathode spot motion are well established: they go asymptotically to Brownian motion for infinitesimal step width. The power spectrum of the arc voltage noise falls as 1/f 2 , where f is frequency, supporting a fractal spot model associated with Brownian motion

Development and validation of a dried blood spot assay for the quantification of ribavirin using liquid chromatography coupled to mass spectrometry

Science.gov (United States)

Jimmerson, Leah C.; Zheng, Jia-Hua; Bushman, Lane R.; MacBrayne, Christine E.; Anderson, Peter L.; Kiser, Jennifer J.

2014-01-01

Efficient, inexpensive and sensitive assays for the measurement of drugs are of interest for pharmacokinetic and pharmacodynamics (PK-PD) analysis. Dried blood spots (DBS) are a unique bioanaltyical matrix with the potential to fulfill this interest for the measurement of numerous analytes. Here we describe the development and validation of a reversed-phase high performance liquid chromatographic (LC), tandem mass spectrometry (MS/MS) assay for the determination of ribavirin (RBV) in DBS. A 3mm punch from spotted and dried whole blood was extracted in methanol utilizing isotopically labeled internal standard for LC-MS/MS analysis. Validation was performed over a range of 0.05 μg/mL to 10.0 μg/mL and the method was shown to be precise (coefficient of variation ≤ 15%) and accurate (within ±15% of control). These acceptance criteria were met for hematocrit ranges of 20-54%, for center versus edge punches and for spot volumes from 10-60 μL. RBV was stable for up to 140 days at room temperature and −20°C as well as for three freeze/thaw cycles. Correlation of RBV in DBS versus in plasma yielded r2 ≥ 0.98 demonstrating that DBS can be used as an alternative to plasma for PK-PD studies in human subjects. PMID:24291608

Geometrical optimization of an ellipsoidal plasma mirror toward tight focusing of ultra-intense laser pulse

International Nuclear Information System (INIS)

Kon, A; Nakatsutsumi, M; Chen, Z L; Kodama, R; Buffechoux, S; Fuchs, J; Jin, Z

2010-01-01

We developed for the first time, very compact ( 3 ) extremely low f-number (f/number = 0.4) confocal ellipsoid focusing systems. Direct measurement of the laser focal spot using a low-energy laser beam indicates 1/5 reduction of the spot size compared to standard focusing (using a f/2.7 optics). Such mirror is thus able to achieve significant enhancement of the focused laser intensity without modifying the laser system itself. The mirror is then used under plasma mirror regime which enables us to compactify the size, to liberate us from the anxiety of protecting the optics from target debris after shots, and to enhance the temporal contrast. In this paper, we focus our attention to designing and optimizing the geometry of such innovative plasma optics.

Second harmonic electron cyclotron emission studies of Tokapole-II plasmas

International Nuclear Information System (INIS)

Sengstacke, M.A.

1984-03-01

The electron temperature is an important parameter in plasma physics. The intensity of electron cyclotron emission (ECE) is a function of the electron temperature. This function reduces to a direct proportionality for optically thick plasmas. Thus a study of ECE can help us understand various plasma properties. The principal diagnostic used is a radiometer consisting of a microwave superheterodyne receiver operating in the K band, (26.5,40) GHz, and fed by a three inch parabolic mirror with a spot size of about 4.4 cm. The entire microwave assembly can be rotated through 90 0 about the mirror axis to facilitate polarization measurements. A ray tracing analysis of Tokapole-II shows that refraction is significant for plasmas observed in this work

Laser Spot Detection Based on Reaction Diffusion

OpenAIRE

Alejandro Vázquez-Otero; Danila Khikhlukha; J. M. Solano-Altamirano; Raquel Dormido; Natividad Duro

2016-01-01

Center-location of a laser spot is a problem of interest when the laser is used for processing and performing measurements. Measurement quality depends on correctly determining the location of the laser spot. Hence, improving and proposing algorithms for the correct location of the spots are fundamental issues in laser-based measurements. In this paper we introduce a Reaction Diffusion (RD) system as the main computational framework for robustly finding laser spot centers. The method presente...

On the control of filamentation of intense laser beams propagating in underdense plasma

International Nuclear Information System (INIS)

Williams, E.A.

2006-01-01

In indirect drive inertial confinement fusion ignition designs, the laser energy is delivered into the hohlraum through the laser entrance holes (LEHs), which are sized as small as practicable to minimize x-ray radiation losses. On the other hand, deleterious laser plasma processes, such as filamentation and stimulated backscatter, typically increase with laser intensity. Ideally, therefore, the laser spot shape should be a close fit to the LEH, with uniform (envelope) intensity in the spot and minimal energy at larger radii spilling onto the LEH material. This keeps the laser intensity as low as possible, consistent with the area of the LEH aperture and the power requirements of the design. This can be achieved (at least for apertures significantly larger than the laser's aberrated focal spot) by the use of custom-designed phase plates. However, outfitting the 192-beam National Ignition Facility [J. A. Paisner, E. M. Campbell, and W. J. Hogan, Fusion Tech. 26, 755 1994)] laser with multiple sets of phase plates optimized for a variety of different LEH aperture sizes is an expensive proposition. It is thus important to assess the impact on laser-plasma interaction processes of using phase plates with a smaller than optimum focal spot (or even no phase plates at all!) and then defocusing the beam to expand it to fill the LEH and lower its intensity. Significant effects are found from changes in the characteristic sizes of the laser speckle, from the lack of uniformity of the laser envelope out of the focal plane and on the efficacy of additional polarization smoothing and/or smoothing by spectral dispersion (SSD). These effects are quantified with analytic estimates and simulations using PF3D, our laser-plasma interaction code

7 CFR 28.415 - Low Middling Light Spotted Color.

Science.gov (United States)

2010-01-01

... 7 Agriculture 2 2010-01-01 2010-01-01 false Low Middling Light Spotted Color. 28.415 Section 28... Spotted Color. Low Middling Light Spotted Color is color which in spot or color, or both, is between Low Middling Color and Low Middling Spotted Color. ...

PyTranSpot: A tool for multiband light curve modeling of planetary transits and stellar spots

Science.gov (United States)

Juvan, Ines G.; Lendl, M.; Cubillos, P. E.; Fossati, L.; Tregloan-Reed, J.; Lammer, H.; Guenther, E. W.; Hanslmeier, A.

2018-02-01

Several studies have shown that stellar activity features, such as occulted and non-occulted starspots, can affect the measurement of transit parameters biasing studies of transit timing variations and transmission spectra. We present PyTranSpot, which we designed to model multiband transit light curves showing starspot anomalies, inferring both transit and spot parameters. The code follows a pixellation approach to model the star with its corresponding limb darkening, spots, and transiting planet on a two dimensional Cartesian coordinate grid. We combine PyTranSpot with a Markov chain Monte Carlo framework to study and derive exoplanet transmission spectra, which provides statistically robust values for the physical properties and uncertainties of a transiting star-planet system. We validate PyTranSpot's performance by analyzing eleven synthetic light curves of four different star-planet systems and 20 transit light curves of the well-studied WASP-41b system. We also investigate the impact of starspots on transit parameters and derive wavelength dependent transit depth values for WASP-41b covering a range of 6200-9200 Å, indicating a flat transmission spectrum.

Interaction of energetic ions with high-density plasmas

International Nuclear Information System (INIS)

Gericke, D.O.; Edie, D.; Grinenko, A.; Vorberger, J.

2010-01-01

Complete text of publication follows. The talk will review the importance of energetic ions in different inertial confinement fusion scenarios: i) heavy ion beams are very efficient drivers that can deliver the energy for compression in indirect as well as direct drive approaches; ii) the interaction of α-particles, that are created in a burning plasma, with the surrounding cold plasma is essential for creating a burn wave; iii) laser-produced ion beams are also a strong candidate to create the hot spot needed for fast ignition. In all applications the ions interact with dense matter that is characterized by strongly coupled ions and (possibly) partially degenerate electrons. Moreover, the coupling between beam ions and target electrons can be strong as well. Under these conditions, standard approaches for the beam-plasma interactions process are known to fail. The presentation will demonstrate how advanced models for the energy loss of ions in dense plasmas can resolve the issues mentioned above. These models are largely built on quantum kinetic theory that is able to describe degeneracy and strong coupling in a systematic way. In particular, strong interactions require a quantum description for electron-ion collisions in dense plasma environments, which is done by direct solutions of the Schroedinger equation. Degeneracy and collective excitations can be included via the Lenard-Balescu description where strong interactions may be included via a pseudo-potential approach. Finally, results are shown for all three fusion applications described above. The effects related to strong coupling and degeneracy mainly concern the end of the stopping range where the beam ion dose not have enough energy to excite all possible degrees of freedom and, thus, certain processes are frozen out. However, we also find a significant reduction of the range for swift heavy ions in the GeV-range when stopping in dense matter is considered. The stopping range of α-particles in the

Rocky Mountain spotted fever in Argentina.

Science.gov (United States)

Paddock, Christopher D; Fernandez, Susana; Echenique, Gustavo A; Sumner, John W; Reeves, Will K; Zaki, Sherif R; Remondegui, Carlos E

2008-04-01

We describe the first molecular confirmation of Rickettsia rickettsii, the cause of Rocky Mountain spotted fever (RMSF), from a tick vector, Amblyomma cajennense, and from a cluster of fatal spotted fever cases in Argentina. Questing A. cajennense ticks were collected at or near sites of presumed or confirmed cases of spotted fever rickettsiosis in Jujuy Province and evaluated by polymerase chain reaction assays for spotted fever group rickettsiae. DNA of R. rickettsii was amplified from a pool of A. cajennense ticks and from tissues of one of four patients who died during 2003-2004 after illnesses characterized by high fever, severe headache, myalgias, and petechial rash. The diagnosis of spotted fever rickettsiosis was confirmed in the other patients by indirect immunofluorescence antibody and immunohistochemical staining techniques. These findings show the existence of RMSF in Argentina and emphasize the need for clinicians throughout the Americas to consider RMSF in patients with febrile rash illnesses.

Crack imaging by pulsed laser spot thermography

International Nuclear Information System (INIS)

Li, T; Almond, D P; Rees, D A S; Weekes, B

2010-01-01

A surface crack close to a spot heated by a laser beam impedes lateral heat flow and produces alterations to the shape of the thermal image of the spot that can be monitored by thermography. A full 3D simulation has been developed to simulate heat flow from a laser heated spot in the proximity of a crack. The modelling provided an understanding of the ways that different parameters affect the thermal images of laser heated spots. It also assisted in the development of an efficient image processing strategy for extracting the scanned cracks. Experimental results show that scanning pulsed laser spot thermography has considerable potential as a remote, non-contact crack imaging technique.

Spot Welding of Honeycomb Structures

Science.gov (United States)

Cohal, V.

2017-08-01

Honeycomb structures are used to prepare meals water jet cutting machines for textile. These honeycomb structures are made of stainless steel sheet thickness of 0.1-0.2 mm. Corrugated sheet metal strips are between two gears with special tooth profile. Hexagonal cells for obtaining these strips are welded points between them. Spot welding device is three electrodes in the upper part, which carries three welding points across the width of the strip of corrugated sheet metal. Spot welding device filled with press and advance mechanisms. The paper presents the values of the regime for spot welding.

7 CFR 28.412 - Strict Middling Light Spotted Color.

Science.gov (United States)

2010-01-01

... 7 Agriculture 2 2010-01-01 2010-01-01 false Strict Middling Light Spotted Color. 28.412 Section 28... Light Spotted Color. Strict Middling Light Spotted Color is color which in spot or color, or both, is between Strict Middling Color and Strict Middling Spotted Color. ...

7 CFR 28.411 - Good Middling Light Spotted Color.

Science.gov (United States)

2010-01-01

... 7 Agriculture 2 2010-01-01 2010-01-01 false Good Middling Light Spotted Color. 28.411 Section 28... Light Spotted Color. Good Middling Light Spotted Color is color which in spot or color, or both, is between Good Middling Color and Good Middling Spotted Color. ...

Age-related differences in plasma proteins: how plasma proteins change from neonates to adults.

Directory of Open Access Journals (Sweden)

Vera Ignjatovic

Full Text Available The incidence of major diseases such as cardiovascular disease, thrombosis and cancer increases with age and is the major cause of mortality world-wide, with neonates and children somehow protected from such diseases of ageing. We hypothesized that there are major developmental differences in plasma proteins and that these contribute to age-related changes in the incidence of major diseases. We evaluated the human plasma proteome in healthy neonates, children and adults using the 2D-DIGE approach. We demonstrate significant changes in number and abundance of up to 100 protein spots that have marked differences in during the transition of the plasma proteome from neonate and child through to adult. These proteins are known to be involved in numerous physiological processes such as iron transport and homeostasis, immune response, haemostasis and apoptosis, amongst others. Importantly, we determined that the proteins that are differentially expressed with age are not the same proteins that are differentially expressed with gender and that the degree of phosphorylation of plasma proteins also changes with age. Given the multi-functionality of these proteins in human physiology, understanding the differences in the plasma proteome in neonates and children compared to adults will make a major contribution to our understanding of developmental biology in humans.

Dried blood spot analysis of (+) and (-) darunavir enantiomers on immobilized amylose tris-(3, 5-dimethylphenylcarbamate) LC and its application to pharmacokinetics.

Science.gov (United States)

Ramisetti, Nageswara Rao; Arnipalli, Manikanta Swamy; Nimmu, Narendra Varma

2015-12-01

Dried blood spot analysis is an innovative novel blood sampling technique gaining interest in drug discovery and development processes owing to its inherent advantages over the conventional whole blood, plasma or serum sample collection. The present manuscript describes the development and validation of a highly sensitive and precise method of evaluation of pharmacokinetics of (+) and (-) darunavir enantiomers on rat dried blood spots. The enantiomers on rat dried blood spots were extracted into methanol and separated by LC on a Chiralpak IA column using hexane and ethanol containing 0.1% DEA (75:25, v/v) as a mobile phase at 20°C; both the enantiomers were detected at 266 nm using a photodiode array detector. The method was validated in terms of selectivity, linearity, accuracy, precision and stability as per the US Food and Drug and Administration guidelines. The hematocrit effect on extraction recovery was evaluated and the mean recoveries of (-) and (+) enantiomers of darunavir from dried blood spots were found to be 85.76 and 88.91% respectively. The intra- and inter-day precision and accuracy were 3.1-8.4 and 0.8-4.8% respectively. The developed method was successfully applied to a pharmacokinetic study of (+) and (-) enantiomers of darunavir on rat dried blood spots. Copyright © 2015 John Wiley & Sons, Ltd.

Effect of ambient humidity on the rate at which blood spots dry and the size of the spot produced.

Science.gov (United States)

Denniff, Philip; Woodford, Lynsey; Spooner, Neil

2013-08-01

For shipping and storage, dried blood spot (DBS) samples must be sufficiently dry to protect the integrity of the sample. When the blood is spotted the humidity has the potential to affect the size of the spot created and the speed at which it dries. The area of DBS produced on three types of substrates were not affected by the humidity under which they were generated. DBS samples reached a steady moisture content 150 min after spotting and 90 min for humidities less than 60% relative humidity. All packaging materials examined provided some degree of protection from external extreme conditions. However, none of the packaging examined provided a total moisture barrier to extreme environmental conditions. Humidity was shown not to affect the spot area and DBS samples were ready for shipping and storage 2 h after spotting. The packing solutions examined all provided good protection from external high humidity conditions.

Demography of Northern Spotted Owls in southwestern Oregon

Science.gov (United States)

Zabel, Cynthia J.; Salmons, Susan E.; Forsman, Eric D.; DeStefano, Stephen; Raphael, Martin G.; Gutierrez, R.J.

1996-01-01

Northern Spotted Owls (Strix occidentalis caurina) are associated with lower elevation, commercially valuable, late-successional coniferous forests in the Pacific Northwest. Meta-analyses of demographic parameters indicate that Northern Spotted Owl populations are declining throughout their range (Anderson and Burnham 1992, Burnham et al. this volume). Recent research has attempted to determine whether management activities have affected the viability of Spotted Owl populations, and results have led to development of conservation plans for the species (Dawson et al. 1987, Thomas et al. 1990, Murphy and Noon 1992, USDI 1992, Thomas et al. 1993b).In the Recovery Plan for the Northern Spotted Owl (USDI 1992b) threats to the species were identified as small population sizes, declining populations, limited amounts of habitat, continued loss and fragmentation of habitat, geographically isolated populations, and predation and competition from other avian species. Weather and fire are natural processes that also may affect reproductive success of Spotted Owls. Weather may be a factor in the high annual variability in fecundity of Spotted Owls, as has been suggested for other predatory bird species (Newton, 1979, 1986). However, these factors have not been addressed in previous studies of Spotted Owls.Our objectives were to estimate survival, fecundity, and annual rates of population change (l) for resident, territorial female Spotted Owls at two study areas in the coastal mountains of southwestern Oregon. We tested if the amount of rainfall was correlated with reproduction of Spotted Owls. While surveying for Spotted Owls, we documented the increased presence of Barred Owls (Strix varia), a potential competitor of Spotted Owls.

Unblinding the dark matter blind spots

International Nuclear Information System (INIS)

Han, Tao; Kling, Felix

2017-01-01

The dark matter (DM) blind spots in the Minimal Supersymmetric Standard Model (MSSM) refer to the parameter regions where the couplings of the DM particles to the Z-boson or the Higgs boson are almost zero, leading to vanishingly small signals for the DM direct detections. In this paper, we carry out comprehensive analyses for the DM searches under the blind-spot scenarios in MSSM. Guided by the requirement of acceptable DM relic abundance, we explore the complementary coverage for the theory parameters at the LHC, the projection for the future underground DM direct searches, and the indirect searches from the relic DM annihilation into photons and neutrinos. We find that (i) the spin-independent (SI) blind spots may be rescued by the spin-dependent (SD) direct detection in the future underground experiments, and possibly by the indirect DM detections from IceCube and SuperK neutrino experiments; (ii) the detection of gamma rays from Fermi-LAT may not reach the desirable sensitivity for searching for the DM blind-spot regions; (iii) the SUSY searches at the LHC will substantially extend the discovery region for the blind-spot parameters. As a result, the dark matter blind spots thus may be unblinded with the collective efforts in future DM searches.

Non-equilibrium between ions and electrons inside hot spots from National Ignition Facility experiments

OpenAIRE

Zhengfeng Fan; Yuanyuan Liu; Bin Liu; Chengxin Yu; Ke Lan; Jie Liu

2017-01-01

The non-equilibrium between ions and electrons in the hot spot can relax the ignition conditions in inertial confinement fusion [Fan et al., Phys. Plasmas 23, 010703 (2016)], and obvious ion-electron non-equilibrium could be observed by our simulations of high-foot implosions when the ion-electron relaxation is enlarged by a factor of 2. On the other hand, in many shots of high-foot implosions on the National Ignition Facility, the observed X-ray enhancement factors due to ablator mixing into...

Heterologous expression of Anabaena PCC 7120 all3940 (a Dps family gene) protects Escherichia coli from nutrient limitation and abiotic stresses

International Nuclear Information System (INIS)

Narayan, Om Prakash; Kumari, Nidhi; Rai, Lal Chand

2010-01-01

This study presents first hand data on the cloning and heterologous expression of Anabaena PCC 7120 all3940 (a dps family gene) in combating nutrients limitation and multiple abiotic stresses. The Escherichia coli transformed with pGEX-5X-2-all3940 construct when subjected to iron, carbon, nitrogen, phosphorus limitation and carbofuron, copper, UV-B, heat, salt and cadmium stress registered significant increase in growth over the cells transformed with empty vector under iron (0%), carbon (0.05%), nitrogen (3.7 mM) and phosphorus (2 mM) limitation and carbofuron (0.025 mg ml -1 ), CuCl 2 (1 mM), UV-B (10 min), heat (47 o C), NaCl (6% w/v) and CdCl 2 (4 mM) stress. Enhanced expression of all3940 gene measured by semi-quantitative RT-PCR at different time points under above mentioned treatments clearly demonstrates its role in tolerance against aforesaid abiotic stresses. This study opens the gate for developing transgenic cyanobacteria capable of growing successfully under above mentioned stresses.

Formation test of the plasma micro-undulator

Energy Technology Data Exchange (ETDEWEB)

Kobayashi, Noriyasu; Hashimoto, Kiyoshi; Aoki, Nobutada; Kimura, Hironobu; Konagai, Chikara; Nakagawa, Satoshi [Toshiba Corp., Yokohama, Kanagawa (Japan); Suzuki, Yasuo [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment

2000-03-01

An electrostatic plasma micro-undulator was demonstrated by utilizing methods of a laser interference and resonant photoionization. An ion-ripple can be formed across a relativistic electron beam injected into the micro-undulator. Thereby, synchrotron radiation light can be projected. Neodymium (Nd) target is ablated by a pulsed Nd-YAG laser beam, and the vapor is ionized by another laser beam with a wavelength tuned to a resonant ionization line of Nd atom. The laser beam for ionization is irradiated into Nd vapor using interference optics, and a micro-sized plasma-ripple corresponding to the interference fringes is shaped. In the experiment, the interference fringe with a periodic length from 10 to 300 {mu}m was formed, and the plasma-ripple was observed. The plasma density of order of 10{sup 13} cm{sup -3}, under the experimental condition, was not sufficient to obtain an effect expected as an undulator. However, optimization of a distance from the ablation spot to the laser plasma fringe and increase of laser power could achieve an undulator parameter K of more than 0.1. (author)

Evaluation of actual vs expected photodynamic therapy spot size.

Science.gov (United States)

Ranchod, Tushar M; Brucker, Alexander J; Liu, Chengcheng; Cukras, Catherine A; Hopkins, Tim B; Ying, Gui-Shuang

2009-05-01

To determine the accuracy of the photodynamic therapy (PDT) laser spot size on the retina as generated by 2 Food and Drug Administration (FDA)-approved lasers. Prospective observational case series. Fundus photographs were taken of 1 eye of each of 10 subjects with the WinStation 4000 fundus photography system (OIS; Ophthalmic Imaging Systems, Sacramento, California, USA); disc size was calculated using OIS software. Slit-lamp photographs were taken of the PDT laser spot focused on the retina adjacent to the optic disc, using various spot sizes in combination with 3 different contact lenses and 2 different lasers. Spot size at the retina was determined by measuring the ratio of disc diameter to spot diameter in Adobe Photoshop (San Jose, California, USA) and applying this ratio to the OIS disc measurements. Spot size at the retina averaged 87% of expected spot size for the Coherent Opal laser (Coherent Inc, Santa Clara, California, USA) and 104% of expected spot size for the Zeiss Visulas laser (Carl Zeiss Meditec Inc, Dublin, California, USA)(P = .002). Multivariate analysis demonstrated that percentage of expected spot size decreased with larger spot diameter (P = .01 for Coherent laser; P = .02 for Zeiss laser). PDT spot size at the retina appears to be consistently smaller than expected for the Coherent laser while the spot size was consistently within 10% of expected size for the Zeiss laser. The deviation from expected size increased with larger spot size using the Coherent laser.

Laser Spot Detection Based on Reaction Diffusion.

Science.gov (United States)

Vázquez-Otero, Alejandro; Khikhlukha, Danila; Solano-Altamirano, J M; Dormido, Raquel; Duro, Natividad

2016-03-01

Center-location of a laser spot is a problem of interest when the laser is used for processing and performing measurements. Measurement quality depends on correctly determining the location of the laser spot. Hence, improving and proposing algorithms for the correct location of the spots are fundamental issues in laser-based measurements. In this paper we introduce a Reaction Diffusion (RD) system as the main computational framework for robustly finding laser spot centers. The method presented is compared with a conventional approach for locating laser spots, and the experimental results indicate that RD-based computation generates reliable and precise solutions. These results confirm the flexibility of the new computational paradigm based on RD systems for addressing problems that can be reduced to a set of geometric operations.

Insights from ecological niche modeling on the taxonomic distinction and niche differentiation between the black-spotted and red-spotted tokay geckoes (Gekko gecko)

OpenAIRE

Zhang, Yueyun; Chen, Chongtao; Li, Li; Zhao, Chengjian; Chen, Weicai; Huang, Yong

2014-01-01

The black-spotted tokay and the red-spotted tokay are morphologically distinct and have largely allopatric distributions. The black-spotted tokay is characterized by a small body size and dark skin with sundry spots, while the red-spotted tokay has a relatively large body size and red spots. Based on morphological, karyotypic, genetic, and distribution differences, recent studies suggested their species status; however, their classifications remain controversial, and additional data such as e...

Small laser spot versus standard laser spot photodynamic therapy for idiopathic choroidal neovascularization: a randomized controlled study.

Science.gov (United States)

Li, Xiao-xin; Tao, Yong

2012-12-01

Idiopathic choroidal neovascularization (ICNV) affects young patients and thus may have a significant impact on vision and life quality over a patient's lifespan. This study was designed to compare the visual outcome and retinal pigment epithelium (RPE) damage after photodynamic therapy (PDT) with small laser spot and PDT with standard laser spot for idiopathic choroidal neovascularization (ICNV). This was a randomized controlled study. Fifty-two patients with ICNV were enrolled and randomly divided into a study group (small laser spot PDT, n = 27) and a control group (standard laser spot PDT, n = 25). Best corrected visual acuity (BCVA), optic coherence tomography (OCT) and fluorescein angiography (FA) findings were the main measurements. The patients were followed up 1 week, 1, 3, 6, 9 months and 1 year after PDT. BCVA improvement was statistically significantly higher in the study group than the control group at 6-month ((25.53 ± 15.01) letters vs. (14.71 ± 11.66) letters, P = 0.025) and 9-month follow-ups ((27.53 ± 17.78) letters vs. (15.59 ± 12.21) letters, P = 0.039). At 3- and 6-month follow-ups, the quadrants of RPE damage between the two groups varied significantly (P laser spot PDT group than in the standard laser spot PDT group for ICNV.

Dark-ground illumination: a quantitative diagnostic for plasma density

International Nuclear Information System (INIS)

Paul, S.F.

1981-01-01

Radial electron density profiles of a toroidal belt pinch plasma have been obtained by a single measurement. Collimated ruby laser light, incident on the plasma, is focused to a diffraction limited spot (100 μm). The technique, a variation of the dark-ground microscope, involves masking the center of the plasma diffraction pattern with a thin wire. Undiffracted light is blocked by a thin wire, whereas light diffracted by the plasma passes around the wire and onto a photoplate. The resulting interference generates a high contrast fringe pattern whose intensity varies as 1-cosΔ phi, where Δ phi is the phase shift induced by the plasma. The fringes are recorded on Polaroid type 46L transparency film. Using this technique, radial density profiles of the plasma produced in the Columbia Torus I belt pinch have been measured. The plasma minor cross section is elliptical with a approx. 2 cm, b approx. 30 cm and approx. 3 x 10 16 /cm 3 . Average densities as low as 2 x 10 15 /cm 3 have been measured

Ferroelectric Plasma Source for Heavy Ion Beam Charge Neutralization

CERN Document Server

Efthimion, Philip; Gilson, Erik P; Grisham, Larry; Logan, B G; Waldron, William; Yu, Simon

2005-01-01

Plasmas are employed as a medium for charge neutralizing heavy ion beams to allow them to focus to a small spot size. Calculations suggest that plasma at a density of 1-100 times the ion beam density and at a length ~ 0.1-1 m would be suitable. To produce 1 meter plasma, large-volume plasma sources based upon ferroelectric ceramics are being considered. These sources have the advantage of being able to increase the length of the plasma and operate at low neutral pressures. The source will utilize the ferroelectric ceramic BaTiO3 to form metal plasma. The drift tube inner surface of the Neutralized Drift Compression Experiment (NDCX) will be covered with ceramic. High voltage (~ 1-5 kV) is applied between the drift tube and the front surface of the ceramic by placing a wire grid on the front surface. A prototype ferroelectric source 20 cm long produced plasma densities ~ 5x1011 cm-3. The source was integrated into the experiment and successfully charge neutralized the K ion beam. Presently, the 1 meter source ...

Laboratory experiments on plasma jets in a magnetic field using high-power lasers

Directory of Open Access Journals (Sweden)

Nishio K.

2013-11-01

Full Text Available The experiments to simulate astrophysical jet generation are performed using Gekko XII (GXII HIPER laser system at the Institute of Laser Engineering. In the experiments a fast plasma flow generated by shooting a CH plane (10 μm thickness is observed at the rear side of the plane. By separating the focal spot of the main beams, a non-uniform plasma is generated. The non-uniform plasma flow in an external magnetic field (0.2∼0.3 T perpendicular to the plasma is more collimated than that without the external magnetic field. The plasma β, the ratio between the plasma and magnetic pressure, is ≫ 1, and the magnetic Reynolds number is ∼150 in the collimated plasma. It is considered that the magnetic field is distorted by the plasma flow and enhances the jet collimation.

Hollow laser plasma self-confined microjet generation

Science.gov (United States)

Sizyuk, Valeryi; Hassanein, Ahmed; CenterMaterials under Extreme Environment Team

2017-10-01

Hollow laser beam produced plasma (LPP) devices are being used for the generation of the self-confined cumulative microjet. Most important place by this LPP device construction is achieving of an annular distribution of the laser beam intensity by spot. An integrated model is being developed to detailed simulation of the plasma generation and evolution inside the laser beam channel. The model describes in two temperature approximation hydrodynamic processes in plasma, laser absorption processes, heat conduction, and radiation energy transport. The total variation diminishing scheme in the Lax-Friedrich formulation for the description of plasma hydrodynamic is used. Laser absorption and radiation transport models on the base of Monte Carlo method are being developed. Heat conduction part on the implicit scheme with sparse matrixes using is realized. The developed models are being integrated into HEIGHTS-LPP computer simulation package. The integrated modeling of the hollow beam laser plasma generation showed the self-confinement and acceleration of the plasma microjet inside the laser channel. It was found dependence of the microjet parameters including radiation emission on the hole and beam radiuses ratio. This work is supported by the National Science Foundation, PIRE project.

Probing plasma wakefields using electron bunches generated from a laser wakefield accelerator

Science.gov (United States)

Zhang, C. J.; Wan, Y.; Guo, B.; Hua, J. F.; Pai, C.-H.; Li, F.; Zhang, J.; Ma, Y.; Wu, Y. P.; Xu, X. L.; Mori, W. B.; Chu, H.-H.; Wang, J.; Lu, W.; Joshi, C.

2018-04-01

We show experimental results of probing the electric field structure of plasma wakes by using femtosecond relativistic electron bunches generated from a laser wakefield accelerator. Snapshots of laser-driven linear wakes in plasmas with different densities and density gradients are captured. The spatiotemporal evolution of the wake in a plasma density up-ramp is recorded. Two parallel wakes driven by a laser with a main spot and sidelobes are identified in the experiment and reproduced in simulations. The capability of this new method for capturing the electron- and positron-driven wakes is also shown via 3D particle-in-cell simulations.

PENGARUH KURS SPOT DAN KURS FORWARD DALAM MEMPREDIKSI FUTURE SPOT PADA PASAR VALAS KAWASAN ASIA TENGGARA

Directory of Open Access Journals (Sweden)

I Gusti Ayu Kade Diana Yanthi

2013-10-01

Full Text Available The importance of the activity in foreign exchange occur as the result of the development of international trading and increased international money and capital movement. The vast development of international economic  caused  economic relationship  among  countries  will  be  linked  to  each other  and  subsequently improve trading activities in their goods, money and capital flows. The variables used in this study are spot, forward  and future  spot. Based  on  the result  of Regression  Estimation  applied in  hypothesis on foreign currencies exchange which done simultaneously are proven able to predict future spot. The investor and international economic  actor could use spot  exchange rate and forward  exchange rate as a  short terms predictor for the next trimester in 2011.

Stepwise expansion of a surface dielectric barrier discharge as a result of alternation in formation of streamers and leaders

International Nuclear Information System (INIS)

Akishev, Yu; Aponin, G; Balakirev, A; Grushin, M; Petryakov, A; Karal'nik, V; Trushkin, N

2013-01-01

Spatial–temporal development of the plasma sheet structure in a surface dielectric barrier discharge (SDBD) powered with a single long pulse of negative polarity is traced. Ambient air and Ar at atmospheric pressure are used as plasma-forming gases. It is found that current regimes and spatial structures occurring at the development of a long-pulsed discharge differ cardinally as compared with those of a short-pulsed SDBD. In the case of long-pulsed SDBDs, the expansion of the barrier area covered by the plasma sheet and seeded with a surface negative charge occurs in a stepwise manner due to cyclic alternation (one after another) in generation of surface streamers and formation of hot surface leaders from the streamers due to streamer–leader transitions. Leaders, in their turn, initiate new streamers, which serve again as precursors for next-step leader formation, and so on. However, the crucial role in surface charge deposition is played not by streamers and leaders but by a diffusive plasma sheet (DPS), which slowly extends from the sides of streamers and leaders. The expansion of the DPS occurs due to the ionization wave propagating from the sides of the streamers and leaders. The difference in spatial structures of a single long-pulsed and a steady-state sin SDBD is studied. In high-frequency sin SDBDs at negative half-cycle there are only leaders and DPS, but there are no streamers. The reason is that there is no necessity for the formation of leaders due to streamer–leader transitions—leaders are formed at the previous cycle and do not decay strongly till the beginning of the next cycle, and they recover themselves without streamers. (paper)

Laser Spot Detection Based on Reaction Diffusion

Directory of Open Access Journals (Sweden)

Alejandro Vázquez-Otero

2016-03-01

Full Text Available Center-location of a laser spot is a problem of interest when the laser is used for processing and performing measurements. Measurement quality depends on correctly determining the location of the laser spot. Hence, improving and proposing algorithms for the correct location of the spots are fundamental issues in laser-based measurements. In this paper we introduce a Reaction Diffusion (RD system as the main computational framework for robustly finding laser spot centers. The method presented is compared with a conventional approach for locating laser spots, and the experimental results indicate that RD-based computation generates reliable and precise solutions. These results confirm the flexibility of the new computational paradigm based on RD systems for addressing problems that can be reduced to a set of geometric operations.

Rocky Mountain spotted fever, Colombia.

Science.gov (United States)

Hidalgo, Marylin; Orejuela, Leonora; Fuya, Patricia; Carrillo, Pilar; Hernandez, Jorge; Parra, Edgar; Keng, Colette; Small, Melissa; Olano, Juan P; Bouyer, Donald; Castaneda, Elizabeth; Walker, David; Valbuena, Gustavo

2007-07-01

We investigated 2 fatal cases of Rocky Mountain spotted fever that occurred in 2003 and 2004 near the same locality in Colombia where the disease was first reported in the 1930s. A retrospective serosurvey of febrile patients showed that > 21% of the serum samples had antibodies aaainst spotted fever group rickettsiae.

Age Spots

Science.gov (United States)

... for Every Season How to Choose the Best Skin Care Products In This Section Dermatologic Surgery What is dermatologic ... for Every Season How to Choose the Best Skin Care Products Age Spots Treatment Options Learn more about treatment ...

Splitting of turbulent spot in transitional pipe flow

Science.gov (United States)

Wu, Xiaohua; Moin, Parviz; Adrian, Ronald J.

2017-11-01

Recent study (Wu et al., PNAS, 1509451112, 2015) demonstrated the feasibility and accuracy of direct computation of the Osborne Reynolds' pipe transition problem without the unphysical, axially periodic boundary condition. Here we use this approach to study the splitting of turbulent spot in transitional pipe flow, a feature first discovered by E.R. Lindgren (Arkiv Fysik 15, 1959). It has been widely believed that spot splitting is a mysterious stochastic process that has general implications on the lifetime and sustainability of wall turbulence. We address the following two questions: (1) What is the dynamics of turbulent spot splitting in pipe transition? Specifically, we look into any possible connection between the instantaneous strain rate field and the spot splitting. (2) How does the passive scalar field behave during the process of pipe spot splitting. In this study, the turbulent spot is introduced at the inlet plane through a sixty degree wide numerical wedge within which fully-developed turbulent profiles are assigned over a short time interval; and the simulation Reynolds numbers are 2400 for a 500 radii long pipe, and 2300 for a 1000 radii long pipe, respectively. Numerical dye is tagged on the imposed turbulent spot at the inlet. Splitting of the imposed turbulent spot is detected very easily. Preliminary analysis of the DNS results seems to suggest that turbulent spot slitting can be easily understood based on instantaneous strain rate field, and such spot splitting may not be relevant in external flows such as the flat-plate boundary layer.

Full melting of a two-dimensional complex plasma crystal triggered by localized pulsed laser heating

Science.gov (United States)

Couëdel, L.; Nosenko, V.; Rubin-Zuzic, M.; Zhdanov, S.; Elskens, Y.; Hall, T.; Ivlev, A. V.

2018-04-01

The full melting of a two-dimensional plasma crystal was induced in a principally stable monolayer by localized laser stimulation. Two distinct behaviors of the crystal after laser stimulation were observed depending on the amount of injected energy: (i) below a well-defined threshold, the laser melted area recrystallized; (ii) above the threshold, it expanded outwards in a similar fashion to mode-coupling instability-induced melting, rapidly destroying the crystalline order of the whole complex plasma monolayer. The reported experimental observations are due to the fluid mode-coupling instability, which can pump energy into the particle monolayer at a rate surpassing the heat transport and damping rates in the energetic localized melted spot, resulting in its further growth. This behavior exhibits remarkable similarities with impulsive spot heating in ordinary reactive matter.

Laser-plasma interaction with an adaptive optics wavefront-corrected laser beam

International Nuclear Information System (INIS)

Lewis, K.

2008-12-01

The propagation of an intense laser beam trough a preformed plasma is of particular interest in order to achieve laser inertial confinement fusion. Experiments carried out with a near-diffraction limited laser beam, producing a single hot spot interacting with the plasma, delivered new results, presented in this Ph.D. dissertation. In particular the first experimental observation of the filament instability confirms the numerous theoretical and numerical studies on the subject. Beam spreading and filament-ion thresholds are studied thanks to near-field and far-field images, with respect to laser intensity, time and space, and plasma transverse velocity. Same diagnostics have been applied to the stimulated Brillouin scattered light, enabling the first observation of the transverse Brillouin activity in the plasma. (author)

Laser based spot weld characterization

Science.gov (United States)

Jonietz, Florian; Myrach, Philipp; Rethmeier, Michael; Suwala, Hubert; Ziegler, Mathias

2016-02-01

Spot welding is one of the most important joining technologies, especially in the automotive industry. Hitherto, the quality of spot welded joints is tested mainly by random destructive tests. A nondestructive testing technique offers the benefit of cost reduction of the testing procedure and optimization of the fabrication process, because every joint could be examined. This would lead to a reduced number of spot welded joints, as redundancies could be avoided. In the procedure described here, the spot welded joint between two zinc-coated steel sheets (HX340LAD+Z100MB or HC340LA+ZE 50/50) is heated optically on one side. Laser radiation and flash light are used as heat sources. The melted zone, the so called "weld nugget" provides the mechanical stability of the connection, but also constitutes a thermal bridge between the sheets. Due to the better thermal contact, the spot welded joint reveals a thermal behavior different from the surrounding material, where the heat transfer between the two sheets is much lower. The difference in the transient thermal behavior is measured with time resolved thermography. Hence, the size of the thermal contact between the two sheets is determined, which is directly correlated to the size of the weld nugget, indicating the quality of the spot weld. The method performs well in transmission with laser radiation and flash light. With laser radiation, it works even in reflection geometry, thus offering the possibility of testing with just one-sided accessibility. By using heating with collimated laser radiation, not only contact-free, but also remote testing is feasible. A further convenience compared to similar thermographic approaches is the applicability on bare steel sheets without any optical coating for emissivity correction. For this purpose, a proper way of emissivity correction was established.

Advanced spot quality analysis in two-colour microarray experiments

Directory of Open Access Journals (Sweden)

Vetter Guillaume

2008-09-01

Full Text Available Abstract Background Image analysis of microarrays and, in particular, spot quantification and spot quality control, is one of the most important steps in statistical analysis of microarray data. Recent methods of spot quality control are still in early age of development, often leading to underestimation of true positive microarray features and, consequently, to loss of important biological information. Therefore, improving and standardizing the statistical approaches of spot quality control are essential to facilitate the overall analysis of microarray data and subsequent extraction of biological information. Findings We evaluated the performance of two image analysis packages MAIA and GenePix (GP using two complementary experimental approaches with a focus on the statistical analysis of spot quality factors. First, we developed control microarrays with a priori known fluorescence ratios to verify the accuracy and precision of the ratio estimation of signal intensities. Next, we developed advanced semi-automatic protocols of spot quality evaluation in MAIA and GP and compared their performance with available facilities of spot quantitative filtering in GP. We evaluated these algorithms for standardised spot quality analysis in a whole-genome microarray experiment assessing well-characterised transcriptional modifications induced by the transcription regulator SNAI1. Using a set of RT-PCR or qRT-PCR validated microarray data, we found that the semi-automatic protocol of spot quality control we developed with MAIA allowed recovering approximately 13% more spots and 38% more differentially expressed genes (at FDR = 5% than GP with default spot filtering conditions. Conclusion Careful control of spot quality characteristics with advanced spot quality evaluation can significantly increase the amount of confident and accurate data resulting in more meaningful biological conclusions.

Detecting hot spots at hazardous-waste sites

International Nuclear Information System (INIS)

Zirschky, J.; Gilbert, R.O.

1984-01-01

Evaluating the need for remedial cleanup at a waste site involves both finding the average contaminant concentration and identifying highly contaminated areas, or hot spots. A nomographic procedure to determine the sample configuration needed to locate a hot spot is presented. The technique can be used to develop a waste-site sampling plant - to determine either the grid spacing required to detect a hot spot at a given level of confidence, or the probability of finding a hot spot of a certain size, given a particular grid spacing. The method and computer program (ELIPGRID) were developed for locating geologic deposits, but the basic procedure can also be used to detect hot spots at chemical- or nuclear-waste disposal sites. Nomographs based on the original program are presented for three sampling-grid configurations - square, rectangular and triangular

Interelectrode plasma evolution in a hot refractory anode vacuum arc: Theory and comparison with experiment

International Nuclear Information System (INIS)

Beilis, I.I.; Goldsmith, S.; Boxman, R.L.

2002-01-01

In this paper a theoretical study of a hot refractory anode vacuum arc, which was previously investigated experimentally [Phys. Plasmas 7, 3068 (2000)], is presented. The arc was sustained between a thermally isolated refractory anode and a water-cooled copper cathode. The arc started as a multicathode-spot (MCS) vacuum arc and then switched to the hot refractory anode vacuum arc (HRAVA) mode. In the MCS mode, the cathodic plasma jet deposits a film of the cathode material on the anode. Simultaneously, the temperature of the thermally isolated anode begins to rise, reaching eventually a sufficiently high temperature to re-evaporate the deposited material, which is subsequently ionized in the interelectrode gap. The transition to the HRAVA mode is completed when the density of the interelectrode plasma consists mostly of ionized re-evaporated atoms--the anode plasma. The evolution of the HRAVA mode is characterized by the propagation of a luminous plasma plume from the anode to the cathode. The time dependent model of the various physical processes taking place during the transition to the HRAVA mode is represented by a system of equations describing atom re-evaporation, atom ionization through the interaction of the cathode jet and the interelectrode plasma with the anode vapor, plasma plume propagation, plasma radial expansion, plasma energy, and heavy particle density balance. The time dependence of the anode heat flux and the effective anode voltage were obtained by solving these equations. In addition, the time dependent plasma electron temperature, plasma density, anode potential drop, arc voltage, and anode temperature distribution were calculated and compared with previous measurements. It was shown that the observed decrease of the effective anode voltage with time during the mode transition is due to decrease of the heat flux incident on the anode surface from the cathode spot jets

Judging a salmon by its spots: environmental variation is the primary determinant of spot patterns in Salmo salar.

Science.gov (United States)

Jørgensen, Katarina M; Solberg, Monica F; Besnier, Francois; Thorsen, Anders; Fjelldal, Per Gunnar; Skaala, Øystein; Malde, Ketil; Glover, Kevin A

2018-04-12

In fish, morphological colour changes occur from variations in pigment concentrations and in the morphology, density, and distribution of chromatophores in the skin. However, the underlying mechanisms remain unresolved in most species. Here, we describe the first investigation into the genetic and environmental basis of spot pattern development in one of the world's most studied fishes, the Atlantic salmon. We reared 920 salmon from 64 families of domesticated, F1-hybrid and wild origin in two contrasting environments (Hatchery; tanks for the freshwater stage and sea cages for the marine stage, and River; a natural river for the freshwater stage and tanks for the marine stage). Fish were measured, photographed and spot patterns evaluated. In the Hatchery experiment, significant but modest differences in spot density were observed among domesticated, F1-hybrid (1.4-fold spottier than domesticated) and wild salmon (1.7-fold spottier than domesticated). A heritability of 6% was calculated for spot density, and a significant QTL on linkage group SSA014 was detected. In the River experiment, significant but modest differences in spot density were also observed among domesticated, F1-hybrid (1.2-fold spottier than domesticated) and wild salmon (1.8-fold spottier than domesticated). Domesticated salmon were sevenfold spottier in the Hatchery vs. River experiment. While different wild populations were used for the two experiments, on average, these were 6.2-fold spottier in the Hatchery vs. River experiment. Fish in the Hatchery experiment displayed scattered to random spot patterns while fish in the River experiment displayed clustered spot patterns. These data demonstrate that while genetics plays an underlying role, environmental variation represents the primary determinant of spot pattern development in Atlantic salmon.

Impact of spot charge inaccuracies in IMPT treatments.

Science.gov (United States)

Kraan, Aafke C; Depauw, Nicolas; Clasie, Ben; Giunta, Marina; Madden, Tom; Kooy, Hanne M

2017-08-01

Spot charge is one parameter of pencil-beam scanning dose delivery system whose accuracy is typically high but whose required value has not been investigated. In this work we quantify the dose impact of spot charge inaccuracies on the dose distribution in patients. Knowing the effect of charge errors is relevant for conventional proton machines, as well as for new generation proton machines, where ensuring accurate charge may be challenging. Through perturbation of spot charge in treatment plans for seven patients and a phantom, we evaluated the dose impact of absolute (up to 5× 10 6 protons) and relative (up to 30%) charge errors. We investigated the dependence on beam width by studying scenarios with small, medium and large beam sizes. Treatment plan statistics included the Γ passing rate, dose-volume-histograms and dose differences. The allowable absolute charge error for small spot plans was about 2× 10 6 protons. Larger limits would be allowed if larger spots were used. For relative errors, the maximum allowable error size for small, medium and large spots was about 13%, 8% and 6% for small, medium and large spots, respectively. Dose distributions turned out to be surprisingly robust against random spot charge perturbation. Our study suggests that ensuring spot charge errors as small as 1-2% as is commonly aimed at in conventional proton therapy machines, is clinically not strictly needed. © 2017 American Association of Physicists in Medicine.

Sensorimotor cortex ablation induces time-dependent response of ACTH cells in adult rats: behavioral, immunohistomorphometric and hormonal study.

Science.gov (United States)

Lavrnja, Irena; Trifunovic, Svetlana; Ajdzanovic, Vladimir; Pekovic, Sanja; Bjelobaba, Ivana; Stojiljkovic, Mirjana; Milosevic, Verica

2014-02-10

Traumatic brain injury (TBI) represents a serious event with far reaching complications, including pituitary dysfunction. Pars distalis corticotropes (ACTH cells), that represent the active module of hypothalamo-pituitary-adrenocortical axis, seem to be affected as well. Since pituitary failure after TBI has been associated with neurobehavioral impairments the aim of this study was to evaluate the effects of TBI on recovery of motor functions, morphology and secretory activity of ACTH cells in the pituitary of adult rats. Wistar male rats, initially exposed to sensorimotor cortex ablation (SCA), were sacrificed at the 2nd, 7th, 14th and 30th days post-surgery (dps). A beam walking test was used to evaluate the recovery of motor functions. Pituitary glands and blood were collected for morphological and hormonal analyses. During the first two weeks post-injury increased recovery of locomotor function was detected, reaching almost the control value at day 30. SCA induces significant increase of pituitary weights compared to their time-matched controls. The volume of ACTH-immunopositive cells was reduced at the 7th dps, while at the 14th dps their volume was enlarged, in comparison to corresponding sham controls. Volume density of ACTH cells was increased only at 14th dps, while at day 30 this increase was insignificant. The plasma level of ACTH transiently increased after the injury. The most pronounced changes were observed at the 7th and 14th dps, and were followed by decrease toward control levels at the 30th dps. Thus, temporal changes in the hypothalamic-pituitary-adrenal axis after traumatic brain injury appear to correlate with the recovery process. Copyright © 2013 Elsevier Inc. All rights reserved.

A MULTIWAVELENGTH STUDY OF THE HIGH SURFACE BRIGHTNESS HOT SPOT IN PKS 1421-490

International Nuclear Information System (INIS)

Godfrey, L. E. H.; Bicknell, G. V.; Lovell, J. E. J.; Jauncey, D. L.; Gelbord, J.; Schwartz, D. A.; Birkinshaw, M.; Worrall, D. M.; Marshall, H. L.; Georganopoulos, M.; Perlman, E. S.; Murphy, D. W.

2009-01-01

Long Baseline Array imaging of the z = 0.663 broadline radio galaxy PKS 1421-490 reveals a 400 pc diameter high surface brightness hot spot at a projected distance of ∼40 kpc from the active galactic nucleus. The isotropic X-ray luminosity of the hot spot, L 2-10keV = 3 x 10 44 ergs s -1 , is comparable to the isotropic X-ray luminosity of the entire X-ray jet of PKS 0637-752, and the peak radio surface brightness is hundreds of times greater than that of the brightest hot spot in Cygnus A. We model the radio to X-ray spectral energy distribution using a one-zone synchrotron self-Compton model with a near equipartition magnetic field strength of 3 mG. There is a strong brightness asymmetry between the approaching and receding hotspots and the hot spot spectrum remains flat (α ∼ 0.5) well beyond the predicted cooling break for a 3 mG magnetic field, indicating that the hotspot emission may be Doppler beamed. A high plasma velocity beyond the terminal jet shock could be the result of a dynamically important magnetic field in the jet. There is a change in the slope of the hotspot radio spectrum at GHz frequencies, which we model by incorporating a cutoff in the electron energy distribution at γ min ∼ 650, with higher values implied if the hotspot emission is Doppler beamed. We show that a sharp decrease in the electron number density below a Lorentz factor of 650 would arise from the dissipation of bulk kinetic energy in an electron/proton jet with a Lorentz factor Γ jet ∼> 5.

Plasma-induced evolution behavior of space-charge-limited current for multiple-needle cathodes

International Nuclear Information System (INIS)

Li Limin; Liu Lie; Zhang Jun; Wen Jianchun; Liu Yonggui; Wan Hong

2009-01-01

Properties of the plasma and beam flow produced by tufted carbon fiber cathodes in a diode powered by a ∼500 kV, ∼400 ns pulse are investigated. Under electric fields of 230-260 kV cm -1 , the electron current density was in the range 210-280 A cm -2 , and particularly at the diode gap of 20 mm, a maximum beam power density of about 120 MW cm -2 was obtained. It was found that space-charge-limited current exhibited an evolution behavior as the accelerating pulse proceeded. There exists a direct relation between the movement of plasma within the diode and the evolution of space-charge-limited current. Initially in the accelerating pulse, the application of strong electric fields caused the emission sites to explode, forming cathode flares or plasma spots, and in this stage the space-charge-limited current was approximately described by a multiple-needle cathode model. As the pulse proceeded, these plasma spots merged and expanded towards the anode, thus increasing the emission area and shortening the diode gap, and the corresponding space-charge-limited current followed a planar cathode model. Finally, the space-charge-limited current is developed from a unipolar flow into a bipolar flow as a result of the appearance of anode plasma. In spite of the nonuniform distribution of cathode plasma, the cross-sectional uniformity of the extracted electron beam is satisfactory. The plasma expansion within the diode is found to be a major factor in the diode perveance growth and instability. These results show that these types of cathodes can offer promising applications for high-power microwave tubes.

Spot: A Programming Language for Verified Flight Software

Science.gov (United States)

Bocchino, Robert L., Jr.; Gamble, Edward; Gostelow, Kim P.; Some, Raphael R.

2014-01-01

The C programming language is widely used for programming space flight software and other safety-critical real time systems. C, however, is far from ideal for this purpose: as is well known, it is both low-level and unsafe. This paper describes Spot, a language derived from C for programming space flight systems. Spot aims to maintain compatibility with existing C code while improving the language and supporting verification with the SPIN model checker. The major features of Spot include actor-based concurrency, distributed state with message passing and transactional updates, and annotations for testing and verification. Spot also supports domain-specific annotations for managing spacecraft state, e.g., communicating telemetry information to the ground. We describe the motivation and design rationale for Spot, give an overview of the design, provide examples of Spot's capabilities, and discuss the current status of the implementation.

Volume higher; spot price ranges widen

International Nuclear Information System (INIS)

Anon.

1994-01-01

This article is the October 1994 uranium market summary. During this reporting period, volume on the spot concentrates market doubled. Twelve deals took place: three in the spot concentrates market, one in the medium and long-term market, four in the conversion market, and four in the enrichment market. The restricted price range widened due to higher prices at the top end of the range, while the unrestricted price range widened because of lower prices at the bottom end. Spot conversion prices were higher, and enrichment prices were unchanged

Fast mega pixels video imaging of a toroidal plasma in KT5D device

International Nuclear Information System (INIS)

Xu Min; Wang Zhijiang; Lu Ronghua; Sun Xiang; Wen Yizhi; Yu Changxuan; Wan Shude; Liu Wandong; Wang Jun; Xiao Delong; Yu Yi; Zhu Zhenghua; Hu Linyin

2005-01-01

A direct imaging system, viewing visible light emission from plasmas tangentially or perpendicularly, has been set up on the KT5D toroidal device to monitor the real two-dimensional profiles of purely ECR generated plasmas. This system has a typical spatial resolution of 0.2 mm (1280x1024 pixels) when imaging the whole cross section. Interesting features of ECR plasmas have been found. Different from what classical theories have expected, a resonance layer with two or three bright spots, rather than an even vertical band, has been observed. In addition, images also indicate an intermittent splitting and drifting character of the plasmas

Plasma lenses for focusing relativistic electron beams

International Nuclear Information System (INIS)

Govil, R.; Wheeler, S.; Leemans, W.

1997-01-01

The next generation of colliders require tightly focused beams with high luminosity. To focus charged particle beams for such applications, a plasma focusing scheme has been proposed. Plasma lenses can be overdense (plasma density, n p much greater than electron beam density, n b ) or underdense (n p less than 2 n b ). In overdense lenses the space-charge force of the electron beam is canceled by the plasma and the remaining magnetic force causes the electron beam to self-pinch. The focusing gradient is nonlinear, resulting in spherical aberrations. In underdense lenses, the self-forces of the electron beam cancel, allowing the plasma ions to focus the beam. Although for a given beam density, a uniform underdense lens produces smaller focusing gradients than an overdense lens, it produces better beam quality since the focusing is done by plasma ions. The underdense lens can be improved by tapering the density of the plasma for optimal focusing. The underdense lens performance can be enhanced further by producing adiabatic plasma lenses to avoid the Oide limit on spot size due to synchrotron radiation by the electron beam. The plasma lens experiment at the Beam Test Facility (BTF) is designed to study the properties of plasma lenses in both overdense and underdense regimes. In particular, important issues such as electron beam matching, time response of the lens, lens aberrations and shot-to-shot reproducibility are being investigated

Space-time modeling of electricity spot prices

DEFF Research Database (Denmark)

Abate, Girum Dagnachew; Haldrup, Niels

In this paper we derive a space-time model for electricity spot prices. A general spatial Durbin model that incorporates the temporal as well as spatial lags of spot prices is presented. Joint modeling of space-time effects is necessarily important when prices and loads are determined in a network...... in the spot price dynamics. Estimation of the spatial Durbin model show that the spatial lag variable is as important as the temporal lag variable in describing the spot price dynamics. We use the partial derivatives impact approach to decompose the price impacts into direct and indirect effects and we show...... that price effects transmit to neighboring markets and decline with distance. In order to examine the evolution of the spatial correlation over time, a time varying parameters spot price spatial Durbin model is estimated using recursive estimation. It is found that the spatial correlation within the Nord...

Poisson's spot and Gouy phase

Science.gov (United States)

da Paz, I. G.; Soldati, Rodolfo; Cabral, L. A.; de Oliveira, J. G. G.; Sampaio, Marcos

2016-12-01

Recently there have been experimental results on Poisson spot matter-wave interferometry followed by theoretical models describing the relative importance of the wave and particle behaviors for the phenomenon. We propose an analytical theoretical model for Poisson's spot with matter waves based on the Babinet principle, in which we use the results for free propagation and single-slit diffraction. We take into account effects of loss of coherence and finite detection area using the propagator for a quantum particle interacting with an environment. We observe that the matter-wave Gouy phase plays a role in the existence of the central peak and thus corroborates the predominantly wavelike character of the Poisson's spot. Our model shows remarkable agreement with the experimental data for deuterium (D2) molecules.

Note: implementation of a cold spot setup for controlled variation of vapor pressures and its application to an InBr containing discharge lamp.

Science.gov (United States)

Briefi, S

2013-02-01

In order to allow for a systematic investigation of the plasma properties of discharges containing indium halides, which are proposed as an efficient alternative for mercury based low pressure discharge lamps, a controlled variation of the indium halide density is mandatory. This can be achieved by applying a newly designed setup in which a well-defined cold spot location is implemented and the cold spot temperature can be adjusted between 50 and 350 °C without influencing the gas temperature. The performance of the setup has been proved by comparing the calculated evaporated InBr density (using the vapor pressure curve) with the one measured via white light absorption spectroscopy.

7 CFR 28.421 - Good Middling Spotted Color.

Science.gov (United States)

2010-01-01

... 7 Agriculture 2 2010-01-01 2010-01-01 false Good Middling Spotted Color. 28.421 Section 28.421 Agriculture Regulations of the Department of Agriculture AGRICULTURAL MARKETING SERVICE (Standards... Color. Good Middling Spotted Color is color which is better than Strict Middling Spotted Color. ...

Spatiotemporal chaos of self-replicating spots in reaction-diffusion systems.

Science.gov (United States)

Wang, Hongli; Ouyang, Qi

2007-11-23

The statistical properties of self-replicating spots in the reaction-diffusion Gray-Scott model are analyzed. In the chaotic regime of the system, the spots that dominate the spatiotemporal chaos grow and divide in two or decay into the background randomly and continuously. The rates at which the spots are created and decay are observed to be linearly dependent on the number of spots in the system. We derive a probabilistic description of the spot dynamics based on the statistical independence of spots and thus propose a characterization of the spatiotemporal chaos dominated by replicating spots.

High-resolution UV-visible spectroscopy of lunar red spots

Science.gov (United States)

Bruno, B. C.; Lucey, P. G.; Hawke, B. R.

1991-01-01

A spectral reflectance study of selected lunar 'red spots', highland areas characterized by an absorption in the ultraviolet relative to the visible was conducted. Some red spots were suggested to be the sites of ancient highland volcanism. High-resolution spectral data of eight red spots on the western portion of the moon over the wavelength region 0.39-0.82 micron were obtained. Much spectral variation among these red spots in the magnitude as well as the wavelength position of the ultraviolet absorption were found. Spectral structure at visible and near-infrared wavelength were also identified. These spectral differences indicate that red spots do not have a single mineralogical composition, which in turn suggests that red spots may have multiple origins. Additional imaging spectroscopic observations were taken of the Herigonius red spot, a morphologically complex region northeast of Mare Humorum. These data reveal significant spectral differences among the various morphological units within the Herigonius red spot. Although some of these are likely due to the effects of the maturation process, others appear to reflect differences in mineral abundances and composition.

Tuning temperature and size of hot spots and hot-spot arrays.

Science.gov (United States)

Saïdi, Elika; Babinet, Nicolas; Lalouat, Loïc; Lesueur, Jérôme; Aigouy, Lionel; Volz, Sébastian; Labéguerie-Egéa, Jessica; Mortier, Michel

2011-01-17

By using scanning thermal microscopy, it is shown that nanoscale constrictions in metallic microwires deposited on an oxidized silicon substrate can be tuned in terms of temperature and confinement size. High-resolution temperature maps indeed show that submicrometer hot spots and hot-spot arrays are obtained when the SiO(2) layer thickness decreases below 100 nm. When the SiO(2) thickness becomes larger, heat is less confined in the vicinity of the constrictions and laterally spreads all along the microwire. These results are in good agreement with numerical simulations, which provide dependences between silica-layer thickness and nanodot shape and temperature. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

The spot market and the spot price: applicability and limitations

International Nuclear Information System (INIS)

White, G. Jr.

1987-01-01

The subject of spot prices and their relationship to long-term contracting is addressed. The author is associated with Nuexco, which originally was called the Nuclear Exchange Corporation. They use the term Exchange Value which originated in the idea that Nuexco operated an exchange 'bank' - those with too much uranium could 'bank it', those with short-term needs could borrow from the 'bank'. If the borrower repaid slightly more or less the difference was settled using the 'exchange value'. This became used for longer-term transactions and now settling the monthly value is an important part of Nuexco's activities. The exact nature of the Exchange Value is defined. Now more and more buyers are insisting on spot market related pricing even where this is not meaningfully related to uranium production costs. (U.K.)

Is this Red Spot the Blue Spot (locus ceruleum)?

Energy Technology Data Exchange (ETDEWEB)

Choe, Won Sick; Lee, Yu Kyung; Lee, Min Kyung; Hwang, Kyung Hoon [Gachon University Gil Hospital, Incheon (Korea, Republic of)

2010-06-15

The authors report brain images of 18F-FDG-PET in a case of schizophrenia. The images showed strikingly increased bilateral uptake in the locus ceruleum. The locus ceruleum is called the blue spot and known to be a center of the norepinephrinergic system.

Is this Red Spot the Blue Spot (locus ceruleum)?

International Nuclear Information System (INIS)

Choe, Won Sick; Lee, Yu Kyung; Lee, Min Kyung; Hwang, Kyung Hoon

2010-01-01

The authors report brain images of 18F-FDG-PET in a case of schizophrenia. The images showed strikingly increased bilateral uptake in the locus ceruleum. The locus ceruleum is called the blue spot and known to be a center of the norepinephrinergic system.

Towards intelligent video understanding applied to plasma facing component monitoring

International Nuclear Information System (INIS)

Martin, V.; Travere, J.M.; Moncada, V.; Bremond, F.

2011-01-01

In this paper, we promote intelligent plasma facing component video monitoring for both real-time purposes (machine protection issues) and post event analysis purposes (plasma-wall interaction understanding). We propose a vision-based system able to automatically detect and classify into different pre-defined categories thermal phenomena such as localized hot spots or transient thermal events (e.g. electrical arcing) from infrared imaging data of PFCs. This original computer vision system is made intelligent by endowing it with high level reasoning (i.e. integration of a priori knowledge of thermal event spatio-temporal properties to guide the recognition), self-adaptability to varying conditions (e.g. different thermal scenes and plasma scenarios), and learning capabilities (e.g. statistical modelling of event behaviour based on training samples). (authors)

Stabilisation of a three-dimensional boundary layer by base-flow manipulation using plasma actuators

International Nuclear Information System (INIS)

Dörr, P C; Kloker, M J

2015-01-01

The applicability of dielectric barrier discharge plasma actuators for controlling the crossflow-vortex-induced laminar breakdown in a three-dimensional swept-wing-type boundary-layer flow is investigated using direct numerical simulation. Similar to the classical application of suction at the wall the aim is to modify the quasi two-dimensional base flow and to weaken primary crossflow (CF) instability, mainly due to a reduction of the basic CF. Not only localised volumetric forcing by plasma actuators but also CF counter-blowing and spots with a moving wall are investigated to identify effective fundamental mechanisms. It is found that counter blowing always results in partial blockage of the flow and eventually increased CF velocity, whereas moving-wall spots can slightly reduce the CF and the amplitude of crossflow vortices. Using discrete volumetric forcing a significant attenuation even of finite-amplitude crossflow vortices and thus a distinct transition delay is achieved. (paper)

Spot Pricing When Lagrange Multipliers Are Not Unique

DEFF Research Database (Denmark)

Feng, Donghan; Xu, Zhao; Zhong, Jin

2012-01-01

Classical spot pricing theory is based on multipliers of the primal problem of an optimal market dispatch, i.e., the solution of the dual problem. However, the dual problem of market dispatch may yield multiple solutions. In these circumstances, spot pricing or any standard pricing practice based...... on a strict extension of the principles of spot pricing and surplus allocation, we propose a new pricing methodology that can yield unique, impartial, and robust solution. The new method has been analyzed and compared with other pricing approaches in accordance with spot pricing theory. Case studies support...

Mathematical modelling of powder material motion and transportation in high-temperature flow core during plasma coatings application

Science.gov (United States)

Bogdanovich, V. I.; Giorbelidze, M. G.

2018-03-01

A problem of mathematical modelling of powder material motion and transportation in gas thermal flow core has been addressed. Undertaken studies indicate significant impact on dynamics of motion of sprayed particles of phenomenological law for drag coefficient and accounting momentum loss of a plasma jet upon acceleration of these particles and their diameter. It is determined that at great dispersion of spraying particles, they reach detail surface at different velocity and significant particles separation takes place at spraying spot. According to the results of mathematical modelling, requirements for admissible dispersion of diameters of particles used for spraying have been formulated. Research has also allowed reducing separation of particles at the spraying spot due to the selection of the method of powder feed to the anode channel of the plasma torch.

Jumping-droplet electronics hot-spot cooling

Science.gov (United States)

Oh, Junho; Birbarah, Patrick; Foulkes, Thomas; Yin, Sabrina L.; Rentauskas, Michelle; Neely, Jason; Pilawa-Podgurski, Robert C. N.; Miljkovic, Nenad

2017-03-01

Demand for enhanced cooling technologies within various commercial and consumer applications has increased in recent decades due to electronic devices becoming more energy dense. This study demonstrates jumping-droplet based electric-field-enhanced (EFE) condensation as a potential method to achieve active hot spot cooling in electronic devices. To test the viability of EFE condensation, we developed an experimental setup to remove heat via droplet evaporation from single and multiple high power gallium nitride (GaN) transistors acting as local hot spots (4.6 mm × 2.6 mm). An externally powered circuit was developed to direct jumping droplets from a copper oxide (CuO) nanostructured superhydrophobic surface to the transistor hot spots by applying electric fields between the condensing surface and the transistor. Heat transfer measurements were performed in ambient air (22-25 °C air temperature, 20%-45% relative humidity) to determine the effect of gap spacing (2-4 mm), electric field (50-250 V/cm) and applied heat flux (demonstrated to 13 W/cm2). EFE condensation was shown to enhance the heat transfer from the local hot spot by ≈200% compared to cooling without jumping and by 20% compared to non-EFE jumping. Dynamic switching of the electric field for a two-GaN system reveals the potential for active cooling of mobile hot spots. The opportunity for further cooling enhancement by the removal of non-condensable gases promises hot spot heat dissipation rates approaching 120 W/cm2. This work provides a framework for the development of active jumping droplet based vapor chambers and heat pipes capable of spatial and temporal thermal dissipation control.

Jumping-droplet electronics hot-spot cooling

International Nuclear Information System (INIS)

Oh, Junho; Birbarah, Patrick; Foulkes, Thomas; Yin, Sabrina L.; Rentauskas, Michelle

2017-01-01

Demand for enhanced cooling technologies within various commercial and consumer applications has increased in recent decades due to electronic devices becoming more energy dense. This study demonstrates jumping-droplet based electric-field-enhanced (EFE) condensation as a potential method to achieve active hot spot cooling in electronic devices. To test the viability of EFE condensation, we developed an experimental setup to remove heat via droplet evaporation from single and multiple high power gallium nitride (GaN) transistors acting as local hot spots (4.6 mm x 2.6 mm). An externally powered circuit was developed to direct jumping droplets from a copper oxide (CuO) nanostructured superhydrophobic surface to the transistor hot spots by applying electric fields between the condensing surface and the transistor. Heat transfer measurements were performed in ambient air (22-25°C air temperature, 20-45% relative humidity) to determine the effect of gap spacing (2-4 mm), electric field (50-250 V/cm), and heat flux (demonstrated to 13 W/cm"2). EFE condensation was shown to enhance the heat transfer from the local hot spot by ≈ 200% compared to cooling without jumping and by 20% compared to non-EFE jumping. Dynamic switching of the electric field for a two-GaN system reveals the potential for active cooling of mobile hot spots. The opportunity for further cooling enhancement by the removal of non-condensable gases promises hot spot heat dissipation rates approaching 120 W/cm"2. Finally, this work provides a framework for the development of active jumping droplet based vapor chambers and heat pipes capable of spatial and temporal thermal dissipation control.

Intraday price dynamics in spot and derivatives markets

Science.gov (United States)

Kim, Jun Sik; Ryu, Doojin

2014-01-01

This study examines intraday relationships among the spot index, index futures, and the implied volatility index based on the VAR(1)-asymmetric BEKK-MGARCH model. Analysis of a high-frequency dataset from the Korean financial market confirms that there is a strong intraday market linkage between the spot index, KOSPI200 futures, and VKOSPI and that asymmetric volatility behaviour is clearly present in the Korean market. The empirical results indicate that the futures return shock affects the spot market more severely than the spot return shock affects the futures market, though there is a bi-directional causal relationship between the spot and futures markets. Our results, based on a high-quality intraday dataset, satisfy both the positive risk-return relationship and asymmetric volatility effect, which are not reconciled in the frameworks of previous studies.

Modelling vacuum arcs : from plasma initiation to surface interactions

International Nuclear Information System (INIS)

Timko, H.

2011-01-01

A better understanding of vacuum arcs is desirable in many of today's 'big science' projects including linear colliders, fusion devices, and satellite systems. For the Compact Linear Collider (CLIC) design, radio-frequency (RF) breakdowns occurring in accelerating cavities influence efficiency optimisation and cost reduction issues. Studying vacuum arcs both theoretically as well as experimentally under well-defined and reproducible direct-current (DC) conditions is the first step towards exploring RF breakdowns. In this thesis, we have studied Cu DC vacuum arcs with a combination of experiments, a particle-in-cell (PIC) model of the arc plasma, and molecular dynamics (MD) simulations of the subsequent surface damaging mechanism. We have also developed the 2D Arc-PIC code and the physics model incorporated in it, especially for the purpose of modelling the plasma initiation in vacuum arcs. Assuming the presence of a field emitter at the cathode initially, we have identified the conditions for plasma formation and have studied the transitions from field emission stage to a fully developed arc. The 'footing' of the plasma is the cathode spot that supplies the arc continuously with particles; the high-density core of the plasma is located above this cathode spot. Our results have shown that once an arc plasma is initiated, and as long as energy is available, the arc is self-maintaining due to the plasma sheath that ensures enhanced field emission and sputtering.The plasma model can already give an estimate on how the time-to-breakdown changes with the neutral evaporation rate, which is yet to be determined by atomistic simulations. Due to the non-linearity of the problem, we have also performed a code-to-code comparison. The reproducibility of plasma behaviour and time-to-breakdown with independent codes increased confidence in the results presented here. Our MD simulations identified high-flux, high-energy ion bombardment as a possible mechanism forming the early

Modeling deflagration waves out of hot spots

Science.gov (United States)

Partom, Yehuda

2017-01-01

It is widely accepted that shock initiation and detonation of heterogeneous explosives comes about by a two-step process known as ignition and growth. In the first step a shock sweeping through an explosive cell (control volume) creates hot spots that become ignition sites. In the second step, deflagration waves (or burn waves) propagate out of those hot spots and transform the reactant in the cell into reaction products. The macroscopic (or average) reaction rate of the reactant in the cell depends on the speed of those deflagration waves and on the average distance between neighboring hot spots. Here we simulate the propagation of deflagration waves out of hot spots on the mesoscale in axial symmetry using a 2D hydrocode, to which we add heat conduction and bulk reaction. The propagation speed of the deflagration waves may depend on both pressure and temperature. It depends on pressure for quasistatic loading near ambient temperature, and on temperature at high temperatures resulting from shock loading. From the simulation we obtain deflagration fronts emanating out of the hot spots. For 8 to 13 GPa shocks, the emanating fronts propagate as deflagration waves to consume the explosive between hot spots. For higher shock levels deflagration waves may interact with the sweeping shock to become detonation waves on the mesoscale. From the simulation results we extract average deflagration wave speeds.

Model for calculation of spot prices and uncertainties integration; Modelo de calculo de precos spot e integracao de incertezas

Energy Technology Data Exchange (ETDEWEB)

Saraiva, J. Tome [Instituto de Engenharia de Sistemas e Computadores (INESC), Porto (Portugal). E-mail: jsaraiva@inescn.pt

1999-07-01

This paper presents a model for systematic and structured impact evaluation of the uncertainties existent in the load powers, on the spot prices on the various bars of a electric power system. The application developed allows the specification of load power as inaccurate trapezoidal numbers and adopts the DC model for the representation of system exploration conditions. Considering the influence of the loss power on the formulation of a spot prices spatial distribution, the model allows the inclusion of transmission network loss estimation. The results correspond to appurtenance functions of spot prices in each barm, consisting of a discrete set of ordered pais which integrates the spot price values and the appurtenance or compatibility level, in accordance with Fuzzy Sets.

Mononucleosis spot test

Science.gov (United States)

Monospot test; Heterophile antibody test; Heterophile agglutination test; Paul-Bunnell test; Forssman antibody test ... The mononucleosis spot test is done when symptoms of mononucleosis are ... Fatigue Fever Large spleen (possibly) Sore throat Tender ...

RF plasma source for heavy ion beam charge neutralization

International Nuclear Information System (INIS)

Efthimion, Philip C.; Gilson, Erik; Grisham, Larry; Davidson, Ronald C.; Yu, Simon S.; Logan, B. Grant

2003-01-01

Highly ionized plasmas are being used as a medium for charge neutralizing heavy ion beams in order to focus the ion beam to a small spot size. A radio frequency (RF) plasma source has been built at the Princeton Plasma Physics Laboratory (PPPL) in support of the joint Neutralized Transport Experiment (NTX) at the Lawrence Berkeley National Laboratory (LBNL) to study ion beam neutralization with plasma. The goal is to operate the source at pressures ∼ 10 -5 Torr at full ionization. The initial operation of the source has been at pressures of 10 -4 -10 -1 Torr and electron densities in the range of 10 8 -10 11 cm -3 . Recently, pulsed operation of the source has enabled operation at pressures in the 10 -6 Torr range with densities of 10 11 cm -3 . Near 100% ionization has been achieved. The source has been integrated with the NTX facility and experiments have begun

SPOTTED STAR LIGHT CURVES WITH ENHANCED PRECISION

International Nuclear Information System (INIS)

Wilson, R. E.

2012-01-01

The nearly continuous timewise coverage of recent photometric surveys is free of the large gaps that compromise attempts to follow starspot growth and decay as well as motions, thereby giving incentive to improve computational precision for modeled spots. Due to the wide variety of star systems in the surveys, such improvement should apply to light/velocity curve models that accurately include all the main phenomena of close binaries and rotating single stars. The vector fractional area (VFA) algorithm that is introduced here represents surface elements by small sets of position vectors so as to allow accurate computation of circle-triangle overlap by spherical geometry. When computed by VFA, spots introduce essentially no noticeable scatter in light curves at the level of one part in 10,000. VFA has been put into the Wilson-Devinney light/velocity curve program and all logic and mathematics are given so as to facilitate entry into other such programs. Advantages of precise spot computation include improved statistics of spot motions and aging, reduced computation time (intrinsic precision relaxes needs for grid fineness), noise-free illustration of spot effects in figures, and help in guarding against false positives in exoplanet searches, where spots could approximately mimic transiting planets in unusual circumstances. A simple spot growth and decay template quantifies time profiles, and specifics of its utilization in differential corrections solutions are given. Computational strategies are discussed, the overall process is tested in simulations via solutions of synthetic light curve data, and essential simulation results are described. An efficient time smearing facility by Gaussian quadrature can deal with Kepler mission data that are in 30 minute time bins.

X-ray spot film device

International Nuclear Information System (INIS)

1981-01-01

Improvements are described in an X-ray spot film device which is used in conjunction with an X-ray table to make a selected number of radiographic exposures on a single film and to perform fluoroscopic examinations. To date, the spot film devices consist of two X-ray field defining masks, one of which is moved manually. The present device is more convenient to use and speeds up the procedure. (U.K.)

Hot spot manifestation in eclipsing dwarf nova HT Cassiopeiae

OpenAIRE

Bakowska, K.; Olech, A.

2014-01-01

We report the detection of the hot spot in light curves of the eclipsing dwarf nova HT Cassiopeiae during its superoutburst in 2010 November. Analysis of eight reconstructed light curves of the hot spot eclipses showed directly that the brightness of the hot spot was changing significantly during the superoutburst. Thereby, detected hot spot manifestation in HT Cas is the newest observational evidence for the EMT model for dwarf novae.

Integrating sustainable hunting in biodiversity protection in Central Africa: hot spots, weak spots, and strong spots.

Directory of Open Access Journals (Sweden)

John E Fa

Full Text Available Wild animals are a primary source of protein (bushmeat for people living in or near tropical forests. Ideally, the effect of bushmeat harvests should be monitored closely by making regular estimates of offtake rate and size of stock available for exploitation. However, in practice, this is possible in very few situations because it requires both of these aspects to be readily measurable, and even in the best case, entails very considerable time and effort. As alternative, in this study, we use high-resolution, environmental favorability models for terrestrial mammals (N = 165 in Central Africa to map areas of high species richness (hot spots and hunting susceptibility. Favorability models distinguish localities with environmental conditions that favor the species' existence from those with detrimental characteristics for its presence. We develop an index for assessing Potential Hunting Sustainability (PHS of each species based on their ecological characteristics (population density, habitat breadth, rarity and vulnerability, weighted according to restrictive and permissive assumptions of how species' characteristics are combined. Species are classified into five main hunting sustainability classes using fuzzy logic. Using the accumulated favorability values of all species, and their PHS values, we finally identify weak spots, defined as high diversity regions of especial hunting vulnerability for wildlife, as well as strong spots, defined as high diversity areas of high hunting sustainability potential. Our study uses relatively simple models that employ easily obtainable data of a species' ecological characteristics to assess the impacts of hunting in tropical regions. It provides information for management by charting the geography of where species are more or less likely to be at risk of extinction from hunting.

Advanced plasma flow simulations of cathodic-arc and ferroelectric plasma sources for neutralized drift compression experiments

Directory of Open Access Journals (Sweden)

Adam B. Sefkow

2008-07-01

Full Text Available Large-space-scale and long-time-scale plasma flow simulations are executed in order to study the spatial and temporal evolution of plasma parameters for two types of plasma sources used in the neutralized drift compression experiment (NDCX. The results help assess the charge neutralization conditions for ion beam compression experiments and can be employed in more sophisticated simulations, which previously neglected the dynamical evolution of the plasma. Three-dimensional simulations of a filtered cathodic-arc plasma source show the coupling efficiency of the plasma flow from the source to the drift region depends on geometrical factors. The nonuniform magnetic topology complicates the well-known general analytical considerations for evaluating guiding-center drifts, and particle-in-cell simulations provide a self-consistent evaluation of the physics in an otherwise challenging scenario. Plasma flow profiles of a ferroelectric plasma source demonstrate that the densities required for longitudinal compression experiments involving ion beams are provided over the drift length, and are in good agreement with measurements. Simulations involving azimuthally asymmetric plasma creation conditions show that symmetric profiles are nevertheless achieved at the time of peak on-axis plasma density. Also, the ferroelectric plasma expands upstream on the thermal expansion time scale, and therefore avoids the possibility of penetration into the acceleration gap and transport sections, where partial neutralization would increase the beam emittance. Future experiments on NDCX will investigate the transverse focusing of an axially compressing intense charge bunch to a sub-mm spot size with coincident focal planes using a strong final-focus solenoid. In order to fill a multi-tesla solenoid with the necessary high-density plasma for beam charge neutralization, the simulations predict that supersonically injected plasma from the low-field region will penetrate and

Pulsed lower-hybrid wave penetration in reactor plasmas

International Nuclear Information System (INIS)

Cohen, R.H.; Bonoli, P.T.; Porkolab, M.; Rognlien, T.D.

1989-01-01

Providing lower-hybrid power in short, intense (GW) pulses allows enhanced wave penetration in reactor-grade plasmas. We examine nonlinear absorption, ray propagation, and parametric instability of the intense pulses. We find that simultaneously achieving good penetration while avoiding parametric instabilities is possible, but imposes restrictions on the peak power density, pulse duration, and/or r.f. spot shape. In particular, power launched in narrow strips, elongated along the field direction, is desired

Laser dynamics in transversely inhomogeneous plasma and its relevance to wakefield acceleration

Science.gov (United States)

Pathak, V. B.; Vieira, J.; Silva, L. O.; Nam, Chang Hee

2018-05-01

We present full set of coupled equations describing the weakly relativistic dynamics of a laser in a plasma with transverse inhomogeneity. We apply variational principle approach to obtain these coupled equations governing laser spot-size, transverse wavenumber, curvature, transverse centroid, etc. We observe that such plasma inhomogeneity can lead to stronger self-focusing. We further discuss the guiding conditions of laser in parabolic plasma channels. With the help of multi-dimensional particle in cell simulations the study is extended to the blowout regime of laser wakefield acceleration to show laser as well as self-injected electron bunch steering in plasma to generate unconventional particle trajectories. Our simulation results demonstrate that such transverse inhomogeneities due to asymmetric self focusing lead to asymmetric bubble excitation, thus inducing off-axis self-injection.

7 CFR 27.94 - Spot markets for contract settlement purposes.

Science.gov (United States)

2010-01-01

... 7 Agriculture 2 2010-01-01 2010-01-01 false Spot markets for contract settlement purposes. 27.94... CONTAINER REGULATIONS COTTON CLASSIFICATION UNDER COTTON FUTURES LEGISLATION Regulations Spot Markets § 27.94 Spot markets for contract settlement purposes. The following are designated as spot markets for...

On the physical mechanism at the origin of multiple double layers appearance in plasma

International Nuclear Information System (INIS)

Dimitriu, D.G.; Gurlui, S.; Aflori, M.; Ivan, L.M.

2005-01-01

Double layers (DLs) in plasma are nonlinear potential structures consisting of two adjacent layers of positive and negative space charge, respectively. Between these layers a potential jump exists, creating an electric field. A common way to obtain a DL structure is to positively bias an electrode immersed in asymptotic stable plasma. In this way, a complex space charge structure (CSCS) in form of a positive 'nucleus' surrounded by a nearly spherical DL is obtained. Under certain experimental conditions (gas nature and pressure, plasma density, electron temperature) a more complex structure in form of two or more subsequent DLs was observed, which was called multiple double layers (MDL). It appears as several bright and concentric plasma shells attached to the electrode. The successive DLs are located at the abrupt changes of luminosity between two adjacent plasma shells. Probe measurements emphasized that the axial profile of the plasma potential has a stair steps shape, with potential jumps close to the ionization potential of the used gas. Experimental results clarify the essential role of excitation and ionization electron-neutral collisions for the generation and dynamics of MDL structures. However, if the electrode is large, the MDL structure appears non-concentrically, as a network of plasma spheres, near each other, almost equally distributed on the electrode surface. Each of the plasma spots is a CSCS as described above. Here, we will present experimental result on concentric and non-concentric MDL, which prove that the same physical mechanism is at the origin of their appearance in plasma. In this mechanism the electron-neutral impact excitations and ionizations play the key role. A simultaneously generation of both types of MDL was recorded. The dynamics of the MDL structures was analyzed by using the modern methods provided by the nonlinear dynamics. In this way, a scenario of transition to chaos by torus breakdown was emphasized, related with the

The rise and fall of a human recombination hot spot.

Science.gov (United States)

Jeffreys, Alec J; Neumann, Rita

2009-05-01

Human meiotic crossovers mainly cluster into narrow hot spots that profoundly influence patterns of haplotype diversity and that may also affect genome instability and sequence evolution. Hot spots also seem to be ephemeral, but processes of hot-spot activation and their subsequent evolutionary dynamics remain unknown. We now analyze the life cycle of a recombination hot spot. Sperm typing revealed a polymorphic hot spot that was activated in cis by a single base change, providing evidence for a primary sequence determinant necessary, though not sufficient, to activate recombination. This activating mutation occurred roughly 70,000 y ago and has persisted to the present, most likely fortuitously through genetic drift despite its systematic elimination by biased gene conversion. Nonetheless, this self-destructive conversion will eventually lead to hot-spot extinction. These findings define a subclass of highly transient hot spots and highlight the importance of understanding hot-spot turnover and how it influences haplotype diversity.

Motion Interplay as a Function of Patient Parameters and Spot Size in Spot Scanning Proton Therapy for Lung Cancer

Science.gov (United States)

Grassberger, Clemens; Dowdell, Stephen; Lomax, Antony; Sharp, Greg; Shackleford, James; Choi, Noah; Willers, Henning; Paganetti, Harald

2013-01-01

Purpose Quantify the impact of respiratory motion on the treatment of lung tumors with spot scanning proton therapy. Methods and Materials 4D Monte Carlo simulations were used to assess the interplay effect, which results from relative motion of the tumor and the proton beam, on the dose distribution in the patient. Ten patients with varying tumor sizes (2.6-82.3cc) and motion amplitudes (3-30mm) were included in the study. We investigated the impact of the spot size, which varies between proton facilities, and studied single fractions and conventionally fractionated treatments. The following metrics were used in the analysis: minimum/maximum/mean dose, target dose homogeneity and 2-year local control rate (2y-LC). Results Respiratory motion reduces the target dose homogeneity, with the largest effects observed for the highest motion amplitudes. Smaller spot sizes (σ≈3mm) are inherently more sensitive to motion, decreasing target dose homogeneity on average by a factor ~2.8 compared to a larger spot size (σ≈13mm). Using a smaller spot size to treat a tumor with 30mm motion amplitude reduces the minimum dose to 44.7% of the prescribed dose, decreasing modeled 2y-LC from 87.0% to 2.7%, assuming a single fraction. Conventional fractionation partly mitigates this reduction, yielding a 2y-LC of 71.6%. For the large spot size, conventional fractionation increases target dose homogeneity and prevents a deterioration of 2y-LC for all patients. No correlation with tumor volume is observed. The effect on the normal lung dose distribution is minimal: observed changes in mean lung dose and lung V20 are interplay using a large spot size and conventional fractionation. For treatments employing smaller spot sizes and/or in the delivery of single fractions, interplay effects can lead to significant deterioration of the dose distribution and lower 2y-LC. PMID:23462423

Motion Interplay as a Function of Patient Parameters and Spot Size in Spot Scanning Proton Therapy for Lung Cancer

International Nuclear Information System (INIS)

Grassberger, Clemens; Dowdell, Stephen; Lomax, Antony; Sharp, Greg; Shackleford, James; Choi, Noah; Willers, Henning; Paganetti, Harald

2013-01-01

Purpose: To quantify the impact of respiratory motion on the treatment of lung tumors with spot scanning proton therapy. Methods and Materials: Four-dimensional Monte Carlo simulations were used to assess the interplay effect, which results from relative motion of the tumor and the proton beam, on the dose distribution in the patient. Ten patients with varying tumor sizes (2.6-82.3 cc) and motion amplitudes (3-30 mm) were included in the study. We investigated the impact of the spot size, which varies between proton facilities, and studied single fractions and conventionally fractionated treatments. The following metrics were used in the analysis: minimum/maximum/mean dose, target dose homogeneity, and 2-year local control rate (2y-LC). Results: Respiratory motion reduces the target dose homogeneity, with the largest effects observed for the highest motion amplitudes. Smaller spot sizes (σ ≈ 3 mm) are inherently more sensitive to motion, decreasing target dose homogeneity on average by a factor 2.8 compared with a larger spot size (σ ≈ 13 mm). Using a smaller spot size to treat a tumor with 30-mm motion amplitude reduces the minimum dose to 44.7% of the prescribed dose, decreasing modeled 2y-LC from 87.0% to 2.7%, assuming a single fraction. Conventional fractionation partly mitigates this reduction, yielding a 2y-LC of 71.6%. For the large spot size, conventional fractionation increases target dose homogeneity and prevents a deterioration of 2y-LC for all patients. No correlation with tumor volume is observed. The effect on the normal lung dose distribution is minimal: observed changes in mean lung dose and lung V 20 are <0.6 Gy(RBE) and <1.7%, respectively. Conclusions: For the patients in this study, 2y-LC could be preserved in the presence of interplay using a large spot size and conventional fractionation. For treatments using smaller spot sizes and/or in the delivery of single fractions, interplay effects can lead to significant deterioration of the

Complete mitochondrial genome of the red-spotted tokay gecko (Gekko gecko, Reptilia: Gekkonidae): comparison of red- and black-spotted tokay geckos.

Science.gov (United States)

Qin, Xin-Min; Qian, Fang; Zeng, De-Long; Liu, Xiao-Can; Li, Hui-Min

2011-10-01

Here, we sequenced the complete mitochondrial genome of the red-spotted tokay gecko (Squamata: Gekkonidae). The genome is 16,590 bp in size. Its gene arrangement pattern was identical with that of black-spotted tokay gecko. We compared the mitochondrial genome of red-spotted tokay gecko with that of the black-spotted tokay gecko. Nucleotide sequence of the two whole mitochondrial genomes was 97.99% similar, and the relatively high similarity seems to indicate that they may be separated at the subspecies level. The information of mitochondrial genome comparison of the two morphological types of tokay gecko is discussed in detail.

RF plasma probe diagnostics: a method for eliminating measurement errors for Langmuir probes with bare protective shields

Science.gov (United States)

Riaby, V. A.; Masherov, P. E.; Savinov, V. P.; Yakunin, V. G.

2018-02-01

The new DC arc T-plasmatron of long service life [1] is studied. The well known method of the electric field strength measurements in a stabilized arc channel [2] was applied in a modified form as a consequence of the specific form of the presumably diffuse anode spot attached to a gas vortex on the external surface of the anode unit. The electrical field strength was determined assuming that the potential drop across the diffuse anode spot in the new plasmatron was small. This gave the mean argon plasma conductivity: σ≤118 Ohm-1cm-1 for arc currents I ≤ 180 A which agreed with the independent experiment [2] affirming the correctness of the above assumption. Analysis of the known experimental and theoretic data on atmospheric argon plasma conductivity resulted in the selection of R.S.Devoto’s theoretic dependence σ(T) [3] as the most reliable one for T=8000…20000 K at P = 1 atm that allowed the evaluation of the mean argon plasma temperature at the exit of the plasmatron: T ≤ 19500 K.

Rocky Mountain spotted fever in children.

Science.gov (United States)

Woods, Charles R

2013-04-01

Rocky Mountain spotted fever is typically undifferentiated from many other infections in the first few days of illness. Treatment should not be delayed pending confirmation of infection when Rocky Mountain spotted fever is suspected. Doxycycline is the drug of choice even for infants and children less than 8 years old. Copyright © 2013 Elsevier Inc. All rights reserved.

Spot på samtalen:

DEFF Research Database (Denmark)

Danneris, Sophie; Jensen, Tanja Dall; Caswell, Dorte

Spot på samtalen sætter fokus på det, der konkret foregår i samtaler mellem borgere og de beskæftigelsesfaglige medarbejdere i jobcentrene. Da de udsatte grupper i mange tilfælde er langt fra arbejdsmarkedet, er interessen rettet mod, hvilke forhold i kontakten med beskæftigelsessystemet, der...... har betydning hvilke indsatser ledige modtager, men også hvordan de modtager dem. Her rettes blikket mod den centrale del af den beskæftigelsespolitiske indsats som samtalerne udgør. I Spot på samtalen er blikket rettet mod de dynamikker, mønstre og mekanismer, der kommer i spil i samtalerne i...

Aneutronic fusion in a degenerate plasma

International Nuclear Information System (INIS)

Son, S.; Fisch, N.J.

2004-01-01

In a Fermi-degenerate plasma, the electronic stopping of a slow ion is smaller than that given by the classical formula, because some transitions between the electron states are forbidden. The bremsstrahlung losses are then smaller, so that the nuclear burning of an aneutronic fuel is more efficient. Consequently, there occurs a parameter regime in which self-burning is possible. Practical obstacles in this regime that must be overcome before net energy can be realized include the compression of the fuel to an ultra dense state and the creation of a hot spot

Aneutronic Fusion in a Degenerate Plasma

International Nuclear Information System (INIS)

Son, S.; Fisch, N.J.

2004-01-01

In a Fermi-degenerate plasma, the electronic stopping of a slow ion is smaller than that given by the classical formula, because some transitions between the electron states are forbidden. The bremsstrahlung losses are then smaller, so that the nuclear burning of an aneutronic fuel is more efficient. Consequently, there occurs a parameter regime in which self-burning is possible. Practical obstacles in this regime that must be overcome before net energy can be realized include the compression of the fuel to an ultra dense state and the creation of a hot spot

Operational features and air plasma characteristics of a thermal plasma torch with hollow electrodes

International Nuclear Information System (INIS)

Hur, Min; Kim, Keun Su; Hong, Sang Hee

2003-01-01

The operational features and thermal plasma characteristics of a plasma torch with hollow electrodes are investigated based on their dependence on input current, gas flow rate and electrode diameter when air is used as a plasma gas. A plasma torch with a hollow cathode and anode has been designed and fabricated, and the arc voltages and thermal efficiencies are measured from its discharge. The newly modified similarity criteria are derived from the measured data related to torch performances. From the fact that these criteria successfully describe both the arc voltage and thermal efficiency behaviour of the torch, depending on its operating and geometrical parameters, it is proved that they can be usefully applied to the design and operation of high power torches. For the numerical modelling of the interior region of the torch, a cold flow analysis is employed along with a simplified balance equation of the Lorentz and gas dynamic drag forces in order to determine a cathode spot position on the cathode surface. The validity of this method is confirmed by comparison of the calculated and measured net powers. As a practically useful result of this analysis, carried out through this numerical and experimental work, it is suggested that low input current, high gas flow rate and relatively large electrode diameter are more favourable as appropriate operating conditions of the torch for the efficient treatment of hazardous organic wastes

Rocky Mountain Spotted Fever: Statistics and Epidemiology

Science.gov (United States)

... Search Form Controls Cancel Submit Search the CDC Rocky Mountain Spotted Fever (RMSF) Note: Javascript is disabled or is not ... message, please visit this page: About CDC.gov . Rocky Mountain Spotted Fever (RMSF) Transmission Signs and Symptoms Diagnosis and Testing ...

Motion-Dependent Filling-In of Spatiotemporal Information at the Blind Spot.

Science.gov (United States)

Maus, Gerrit W; Whitney, David

2016-01-01

We usually do not notice the blind spot, a receptor-free region on the retina. Stimuli extending through the blind spot appear filled in. However, if an object does not reach through but ends in the blind spot, it is perceived as "cut off" at the boundary. Here we show that even when there is no corresponding stimulation at opposing edges of the blind spot, well known motion-induced position shifts also extend into the blind spot and elicit a dynamic filling-in process that allows spatial structure to be extrapolated into the blind spot. We presented observers with sinusoidal gratings that drifted into or out of the blind spot, or flickered in counterphase. Gratings moving into the blind spot were perceived to be longer than those moving out of the blind spot or flickering, revealing motion-dependent filling-in. Further, observers could perceive more of a grating's spatial structure inside the blind spot than would be predicted from simple filling-in of luminance information from the blind spot edge. This is evidence for a dynamic filling-in process that uses spatiotemporal information from the motion system to extrapolate visual percepts into the scotoma of the blind spot. Our findings also provide further support for the notion that an explicit spatial shift of topographic representations contributes to motion-induced position illusions.

The effects of eating marine- or vegetable-fed farmed trout on the human plasma proteome profiles of healthy men

DEFF Research Database (Denmark)

Rentsch, Maria Louise; Lametsch, René; Bügel, Susanne

2015-01-01

Most human intervention studies have examined the effects on a subset of risk factors, some of which may require long-term exposure. The plasma proteome may reflect the underlying changes in protein expression and activation, and this could be used to identify early risk markers. The aim of the p......Most human intervention studies have examined the effects on a subset of risk factors, some of which may require long-term exposure. The plasma proteome may reflect the underlying changes in protein expression and activation, and this could be used to identify early risk markers. The aim...... of the present study was to evaluate the impact of regular fish intake on the plasma proteome. We recruited thirty healthy men aged 40 to 70 years, who were randomly allocated to a daily meal of chicken or trout raised on vegetable or marine feeds. Blood samples were collected before and after 8 weeks...... of intervention, and after the removal of the twelve most abundant proteins, plasma proteins were separated by two-dimensional gel electrophoresis. Protein spots 4·3 visualised by silver staining were matched by two-dimensional imaging software. Within-subject changes in spots were compared...

7 CFR 27.96 - Quotations in bona fide spot markets.

Science.gov (United States)

2010-01-01

... 7 Agriculture 2 2010-01-01 2010-01-01 false Quotations in bona fide spot markets. 27.96 Section 27... Differences § 27.96 Quotations in bona fide spot markets. The price or value and differences between the price... determined by the sale of spot cotton in such spot market. Quotations shall be determined and maintained in...

Assessing Statistically Significant Heavy-Metal Concentrations in Abandoned Mine Areas via Hot Spot Analysis of Portable XRF Data.

Science.gov (United States)

Kim, Sung-Min; Choi, Yosoon

2017-06-18

To develop appropriate measures to prevent soil contamination in abandoned mining areas, an understanding of the spatial variation of the potentially toxic trace elements (PTEs) in the soil is necessary. For the purpose of effective soil sampling, this study uses hot spot analysis, which calculates a z -score based on the Getis-Ord Gi* statistic to identify a statistically significant hot spot sample. To constitute a statistically significant hot spot, a feature with a high value should also be surrounded by other features with high values. Using relatively cost- and time-effective portable X-ray fluorescence (PXRF) analysis, sufficient input data are acquired from the Busan abandoned mine and used for hot spot analysis. To calibrate the PXRF data, which have a relatively low accuracy, the PXRF analysis data are transformed using the inductively coupled plasma atomic emission spectrometry (ICP-AES) data. The transformed PXRF data of the Busan abandoned mine are classified into four groups according to their normalized content and z -scores: high content with a high z -score (HH), high content with a low z -score (HL), low content with a high z -score (LH), and low content with a low z -score (LL). The HL and LH cases may be due to measurement errors. Additional or complementary surveys are required for the areas surrounding these suspect samples or for significant hot spot areas. The soil sampling is conducted according to a four-phase procedure in which the hot spot analysis and proposed group classification method are employed to support the development of a sampling plan for the following phase. Overall, 30, 50, 80, and 100 samples are investigated and analyzed in phases 1-4, respectively. The method implemented in this case study may be utilized in the field for the assessment of statistically significant soil contamination and the identification of areas for which an additional survey is required.

Assessing Statistically Significant Heavy-Metal Concentrations in Abandoned Mine Areas via Hot Spot Analysis of Portable XRF Data

Directory of Open Access Journals (Sweden)

Sung-Min Kim

2017-06-01

Full Text Available To develop appropriate measures to prevent soil contamination in abandoned mining areas, an understanding of the spatial variation of the potentially toxic trace elements (PTEs in the soil is necessary. For the purpose of effective soil sampling, this study uses hot spot analysis, which calculates a z-score based on the Getis-Ord Gi* statistic to identify a statistically significant hot spot sample. To constitute a statistically significant hot spot, a feature with a high value should also be surrounded by other features with high values. Using relatively cost- and time-effective portable X-ray fluorescence (PXRF analysis, sufficient input data are acquired from the Busan abandoned mine and used for hot spot analysis. To calibrate the PXRF data, which have a relatively low accuracy, the PXRF analysis data are transformed using the inductively coupled plasma atomic emission spectrometry (ICP-AES data. The transformed PXRF data of the Busan abandoned mine are classified into four groups according to their normalized content and z-scores: high content with a high z-score (HH, high content with a low z-score (HL, low content with a high z-score (LH, and low content with a low z-score (LL. The HL and LH cases may be due to measurement errors. Additional or complementary surveys are required for the areas surrounding these suspect samples or for significant hot spot areas. The soil sampling is conducted according to a four-phase procedure in which the hot spot analysis and proposed group classification method are employed to support the development of a sampling plan for the following phase. Overall, 30, 50, 80, and 100 samples are investigated and analyzed in phases 1–4, respectively. The method implemented in this case study may be utilized in the field for the assessment of statistically significant soil contamination and the identification of areas for which an additional survey is required.

Numerical simulations used for a validity check on the laser induced photo-detachment diagnostic method in electronegative plasmas

Energy Technology Data Exchange (ETDEWEB)

Oudini, N. [Laboratoire des plasmas de décharges, Centre de Développement des Technologies Avancées, Cité du 20 Aout BP 17 Baba Hassen, 16081 Algiers (Algeria); Taccogna, F. [Istituto di Metodologie Inorganiche e dei Plasmi, CNR, via Amendola 122/D, 70126 Bari (Italy); Bendib, A. [Laboratoire d' Electronique Quantique, Faculté de Physique, USTHB, El Alia BP 32, Bab Ezzouar 16111, Algiers (Algeria); Aanesland, A. [Laboratoire de Physique des Plasmas (CNRS, Ecole Polytechnique, Sorbonne Universités, UPMC Univ Paris 06, Univ Paris-Sud), École Polytechnique, 91128 Palaiseau Cedex (France)

2014-06-15

Laser photo-detachment is used as a method to measure or determine the negative ion density and temperature in electronegative plasmas. In essence, the method consists of producing an electropositive channel (negative ion free region) via pulsed laser photo-detachment within an electronegative plasma bulk. Electrostatic probes placed in this channel measure the change in the electron density. A second pulse might be used to track the negative ion recovery. From this, the negative ion density and temperature can be determined. We study the formation and relaxation of the electropositive channel via a two-dimensional Particle-In-Cell/Mote Carlo collision model. The simulation is mainly carried out in a Hydrogen plasma with an electronegativity of α = 1, with a parametric study for α up to 20. The temporal and spatial evolution of the plasma potential and the electron densities shows the formation of a double layer (DL) confining the photo-detached electrons within the electropositive channel. This DL evolves into two fronts that move in the opposite directions inside and outside of the laser spot region. As a consequence, within the laser spot region, the background and photo-detached electron energy distribution function relaxes/thermalizes via collisionless effects such as Fermi acceleration and Landau damping. Moreover, the simulations show that collisional effects and the DL electric field strength might play a non-negligible role in the negative ion recovery within the laser spot region, leading to a two-temperature negative ion distribution. The latter result might have important effects in the determination of the negative ion density and temperature from laser photo detachment diagnostic.

Nuclear Fusion Effects Induced in Intense Laser-Generated Plasmas

Directory of Open Access Journals (Sweden)

Lorenzo Torrisi

2013-01-01

Full Text Available Deutered polyethylene (CD2n thin and thick targets were irradiated in high vacuum by infrared laser pulses at 1015W/cm2 intensity. The high laser energy transferred to the polymer generates plasma, expanding in vacuum at supersonic velocity, accelerating hydrogen and carbon ions. Deuterium ions at kinetic energies above 4 MeV have been measured by using ion collectors and SiC detectors in time-of-flight configuration. At these energies the deuterium–deuterium collisions may induce over threshold fusion effects, in agreement with the high D-D cross-section valuesaround 3 MeV energy. At the first instants of the plasma generation, during which high temperature, density and ionacceleration occur, the D-D fusions occur as confirmed by the detection of mono-energetic protonsand neutrons with a kinetic energy of 3.0 MeV and 2.5 MeV, respectively, produced by the nuclear reaction. The number of fusion events depends strongly on the experimental set-up, i.e. on the laser parameters (intensity, wavelength, focal spot dimension, target conditions (thickness, chemical composition, absorption coefficient, presence of secondary targets and used geometry (incidence angle, laser spot, secondary target positions.A number of D-D fusion events of the order of 106÷7 per laser shot has been measured.

Comparison of sodium, potassium, calcium, magnesium, zinc, copper and iron concentrations of elements in 24-h urine and spot urine in hypertensive patients with healthy renal function.

Science.gov (United States)

Zhang, Tianjing; Chang, Xiaoyu; Liu, Wanlu; Li, Xiaoxia; Wang, Faxuan; Huang, Liping; Liao, Sha; Liu, Xiuying; Zhang, Yuhong; Zhao, Yi

2017-12-01

Sodium, potassium, calcium, magnesium, zinc, copper and iron are associated with the sequela of hypertension. The most reliable method for testing those elements is by collecting 24-h urine samples. However, this is cumbersome and collection of spot urine is more convenient in some circumstance. The aim of this study was to compare the concentrations of different elements in 24-h urine and spot urine. Data was collected from a sub-study of China Salt Substitute and Stroke Study. 240 participants were recruited randomly from 12 villages in two counties in Ningxia, China. Both spot and 24-h urine specimens were collected from each patient. Routine urine test was conducted, and concentration of elements was measured using microwave digestion and Inductively Coupled Plasma-Optical Emission Spectrometry. Partial correlation analysis and Spearman correlation analysis were used to investigate the concentration of different elements and the relationship between 24- h urine and spot urine. A partial correlation in sodium, potassium, calcium, magnesium and iron was found between paired 24-h urine and spot urine samples except copper and zinc: 0.430, 0.426, 0.550, 0.221 and 0.191 respectively. Spot urine can replace 24-h urine for estimating some of the elements in hypertensive patients with normal renal function. Copyright © 2017 Elsevier GmbH. All rights reserved.

7 CFR 28.426 - Strict Good Ordinary Spotted Color.

Science.gov (United States)

2010-01-01

... 7 Agriculture 2 2010-01-01 2010-01-01 false Strict Good Ordinary Spotted Color. 28.426 Section 28.426 Agriculture Regulations of the Department of Agriculture AGRICULTURAL MARKETING SERVICE (Standards... Spotted Color. Strict Good Ordinary Spotted Color is color which is within the range represented by a set...

7 CFR 28.424 - Strict Low Middling Spotted Color.

Science.gov (United States)

2010-01-01

... 7 Agriculture 2 2010-01-01 2010-01-01 false Strict Low Middling Spotted Color. 28.424 Section 28.424 Agriculture Regulations of the Department of Agriculture AGRICULTURAL MARKETING SERVICE (Standards... Spotted Color. Strict Low Middling Spotted Color is color which is within the range represented by a set...

Effects of spot parameters in pencil beam scanning treatment planning.

Science.gov (United States)

Kraan, Aafke Christine; Depauw, Nicolas; Clasie, Ben; Giunta, Marina; Madden, Tom; Kooy, Hanne M

2018-01-01

Spot size σ (in air at isocenter), interspot spacing d, and spot charge q influence dose delivery efficiency and plan quality in Intensity Modulated Proton Therapy (IMPT) treatment planning. The choice and range of parameters varies among different manufacturers. The goal of this work is to demonstrate the influence of the spot parameters on dose quality and delivery in IMPT treatment plans, to show their interdependence, and to make practitioners aware of the spot parameter values for a certain facility. Our study could help as a guideline to make the trade-off between treatment quality and time in existing PBS centers and in future systems. We created plans for seven patients and a phantom, with different tumor sites and volumes, and compared the effect of small-, medium-, and large-spot widths (σ = 2.5, 5, and 10 mm) and interspot distances (1σ, 1.5σ, and 1.75σ) on dose, spot charge, and treatment time. Moreover, we quantified how postplanning charge threshold cuts affect plan quality and the total number of spots to deliver, for different spot widths and interspot distances. We show the effect of a minimum charge (or MU) cutoff value for a given proton delivery system. Spot size had a strong influence on dose: larger spots resulted in more protons delivered outside the target region. We observed dose differences of 2-13 Gy (RBE) between 2.5 mm and 10 mm spots, where the amount of extra dose was due to dose penumbra around the target region. Interspot distance had little influence on dose quality for our patient group. Both parameters strongly influence spot charge in the plans and thus the possible impact of postplanning charge threshold cuts. If such charge thresholds are not included in the treatment planning system (TPS), it is important that the practitioner validates that a given combination of lower charge threshold, interspot spacing, and spot size does not result in a plan degradation. Low average spot charge occurs for small spots, small interspot

Thermonuclear plasma physic: inertial confinement fusion; Physique des plasmas thermonucleaires: la fusion par confinement inertiel

Energy Technology Data Exchange (ETDEWEB)

Bayer, Ch.; Juraszek, D

2001-07-01

Inertial Confinement Fusion (ICF) is an approach to thermonuclear fusion in which the fuel contained in a spherical capsule is strongly compressed and heated to achieve ignition and burn. The released thermonuclear energy can be much higher than the driver energy, making energetic applications attractive. Many complex physical phenomena are involved by the compression process, but it is possible to use simple analytical models to analyze the main critical points. We first determine the conditions to obtain fuel ignition. High thermonuclear gains are achieved if only a small fraction of the fuel called hot spot is used to trigger burn in the main fuel compressed on a low isentrope. A simple hot spot model will be described. The high pressure needed to drive the capsule compression are obtained by the ablation process. A simple Rocket model describe the main features of the implosion phase. Several parameters have to be controlled during the compression: irradiation symmetry, hydrodynamical stability and when the driver is a laser, the problems arising from interaction of the EM wave with the plasma. Two different schemes are examined: Indirect Drive which uses X-ray generated in a cavity to drive the implosion and the Fast Ignitor concept using a ultra intense laser beam to create the hot spot. At the end we present the Laser Megajoule (LMJ) project. LMJ is scaled to a thermonuclear gain of the order of ten. (authors)

TSH IRMA of dried blood spots

International Nuclear Information System (INIS)

Tojinda, N.; Pattanachak, C.; Chongchirasiri, S.; Pattanachak, S.; Putrasreni, N.; Pleehachinda, R.; Suwanik, R.

1990-01-01

TSH determination is most useful for screening of neonatal hypothyroid in the population in iodine deficient areas. The NETRIA IRMA method for serum TSH was applied for blood-spot TSH. Cord blood on SS No. 903 filter paper was left dry overnight. The spot of 6 mm diameter, one/tube, was mixed with an assay buffer, diluted labelled m-anti-TSH, and diluted anti-TSH-solid phase. The mixture was rotated for 22-24 hours. After washing twice with wash buffer, it was counted for 1 minute. The standard curve with 0, 5, 10, 25, 50, 100, and 150 mIU/L whole blood was obtained with the maximum binding of 25%. The precision profile was satisfactory with %CV of 0 C) or 4 0 C or -20 0 C. The correlation between serum and blood-spot TSH values (n=120) showed r of 0.9541 and y=1.6123 (BS-TSH) +1.382. The mean of normal cord blood spot TSH (n=142) was 5.27 mIU/L. The technique was found to be precise, sensitive and easy to perform. Mass screening with this developed method is underway

Surface damage characteristics of CFC and tungsten with repetitive ELM-like pulsed plasma irradiation

Energy Technology Data Exchange (ETDEWEB)

Kikuchi, Y., E-mail: ykikuchi@eng.u-hyogo.ac.jp [Graduate School of Engineering, University of Hyogo, 2167 Shosha, Himeji, 671-2280 Hyogo (Japan); Nishijima, D. [Center for Energy Research, University of California at San Diego, 9500 Gilman Drive, La Jolla, CA 92093-0417 (United States); Nakatsuka, M.; Ando, K.; Higashi, T.; Ueno, Y.; Ishihara, M.; Shoda, K.; Nagata, M. [Graduate School of Engineering, University of Hyogo, 2167 Shosha, Himeji, 671-2280 Hyogo (Japan); Kawai, T.; Ueda, Y. [Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita, Osaka 565-0871 (Japan); Fukumoto, N. [Graduate School of Engineering, University of Hyogo, 2167 Shosha, Himeji, 671-2280 Hyogo (Japan); Doerner, R.P. [Center for Energy Research, University of California at San Diego, 9500 Gilman Drive, La Jolla, CA 92093-0417 (United States)

2011-08-01

Surface damage of carbon fiber composite (CFC) and tungsten (W) due to repetitive ELM-like pulsed plasma irradiation has been investigated by using a magnetized coaxial plasma gun. CX2002U CFC and stress-relieved W samples were exposed to repetitive pulsed deuterium plasmas with duration of {approx}0.5 ms, incident ion energy of {approx}30 eV, and surface absorbed energy density of {approx}0.3-0.7 MJ/m{sup 2}. Bright spots on a CFC surface during pulsed plasma exposures were clearly observed with a high-speed camera, indicating a local surface heating. No melting of a W surface was observed under a single plasma pulse exposure at energy density of {approx}0.7 MJ/m{sup 2}, although cracks were formed. Cracking of the W surface grew with repetitive pulsed plasma exposures. Subsequently, the surface melted due to localized heat absorption.

A novel word spotting method based on recurrent neural networks.

Science.gov (United States)

Frinken, Volkmar; Fischer, Andreas; Manmatha, R; Bunke, Horst

2012-02-01

Keyword spotting refers to the process of retrieving all instances of a given keyword from a document. In the present paper, a novel keyword spotting method for handwritten documents is described. It is derived from a neural network-based system for unconstrained handwriting recognition. As such it performs template-free spotting, i.e., it is not necessary for a keyword to appear in the training set. The keyword spotting is done using a modification of the CTC Token Passing algorithm in conjunction with a recurrent neural network. We demonstrate that the proposed systems outperform not only a classical dynamic time warping-based approach but also a modern keyword spotting system, based on hidden Markov models. Furthermore, we analyze the performance of the underlying neural networks when using them in a recognition task followed by keyword spotting on the produced transcription. We point out the advantages of keyword spotting when compared to classic text line recognition.

Particle-wave discrimination in Poisson spot experiments

International Nuclear Information System (INIS)

Reisinger, T; Bracco, G; Holst, B

2011-01-01

Matter-wave interferometry has been used extensively over the last few years to demonstrate the quantum-mechanical wave nature of increasingly larger and more massive particles. We have recently suggested the use of the historical Poisson spot setup to test the diffraction properties of larger objects. In this paper, we present the results of a classical particle van der Waals (vdW) force model for a Poisson spot experimental setup and compare these to Fresnel diffraction calculations with a vdW phase term. We include the effect of disc-edge roughness in both models. Calculations are performed with D 2 and with C 70 using realistic parameters. We find that the sensitivity of the on-axis interference/focus spot to disc-edge roughness is very different in the two cases. We conclude that by measuring the intensity on the optical axis as a function of disc-edge roughness, it can be determined whether the objects behave as de Broglie waves or classical particles. The scaling of the Poisson spot experiment to larger molecular masses is, however, not as favorable as in the case of near-field light-grating-based interferometers. Instead, we discuss the possibility of studying the Casimir-Polder potential using the Poisson spot setup.

Molecular and histological characterization of age spots

Science.gov (United States)

Choi, Wonseon; Yin, Lanlan; Smuda, Christoph; Batzer, Jan; Hearing, Vincent J.; Kolbe, Ludger

2016-01-01

Age spots, also called solar lentigines and lentigo senilis, are light brown to black pigmented lesions of various sizes that typically develop in chronically sun-exposed skin. It is well known that age spots are strongly related to chronic sun exposure and are associated with photodamage and an increased risk for skin cancer, however, the mechanism(s) underlying their development remain poorly understood. We used immunohistochemical analysis and microarray analysis to investigate the processes involved in their formation, focusing on specific markers associated with the functions and proliferation of melanocytes and keratinocytes. A total of 193 genes were differentially expressed in age spots but melanocyte pigment genes were not among them. The increased expression of keratins 5 and 10, markers of basal and suprabasal keratinocytes, respectively, in age spots suggests that the increased proliferation of basal keratinocytes combined with the decreased turnover of suprabasal keratinocytes leads to the exaggerated formation of rete ridges in lesional epidermis which in turn disrupts the normal processing of melanin upwards from the basal layer. Based on our results, we propose a model for the development of age spots that explains the accumulation of melanin and the development of extensive rete ridges in those hyperpigmented lesions. PMID:27621222

Plutonium spot of mixed oxide fuel, 2

International Nuclear Information System (INIS)

Suzuki, Yukio; Maruishi, Yoshihiro; Satoh, Masaichi; Aoki, Toshimasa; Muto, Tadashi

1974-01-01

In a fast reactor, the specification for the homogeneity of plutonium in plutonium-uranium mixed-oxide fuel is mainly dependent on the nuclear characteristics, whereas in a thermal reactor, on thermal characteristics. This homogeneity is measured by autoradiography as the plutonium spot size of the specimens which are arbitrarily chosen fuel pellets from a lot. Although this is a kind of random sampling, it is difficult to apply this method to conventional digital standards including JIS standards. So a special sampling inspection method was studied. First, it is assumed that the shape of plutonium spots is spherical, the size distribution is logarithmic normal, and the standard deviation is constant. Then, if standard deviation and mean spot size are given, the logarithmic normal distribution is decided unitarily, and further if the total weight of plutonium spots for a lot of pellets is known, the number of the spots (No) which does not conform to the specification can be obtained. Then, the fraction defective is defined as No devided by the number of pellets per lot. As to the lot with such fraction defective, the acceptance coefficient of the lot was obtained through calculation, in which the number of sampling, acceptable diameter limit observed and acceptable conditions were used as parameters. (Tai, I.)

Cellular localization of the Escherichia coli SpoT protein.

OpenAIRE

Gentry, D R; Cashel, M

1995-01-01

The SpoT protein of Escherichia coli serves as a source of degradation as well as an apparent source of synthesis of (p)ppGpp. Since the subcellular localization of SpoT might be a clue to its function, we have used SpoT-specific antisera to analyze cell extracts fractionated on sucrose gradients. We find that the SpoT protein is not bound to ribosomes or to either inner or outer membrane fractions. Although the SpoT protein is found in large aggregates, its localization is probably cytosolic.

New 40Ar/39Ar age progression for the Louisville hot spot trail and implications for inter-hot spot motion

Science.gov (United States)

Koppers, Anthony A. P.; Gowen, Molly D.; Colwell, Lauren E.; Gee, Jeffrey S.; Lonsdale, Peter F.; Mahoney, John J.; Duncan, Robert A.

2011-12-01

In this study we present 42 new 40Ar/39Ar incremental heating age determinations that contribute to an updated age progression for the Louisville seamount trail. Louisville is the South Pacific counterpart to the Hawaiian-Emperor seamount trail, both trails representing intraplate volcanism over the same time interval (˜80 Ma to present) and being examples of primary hot spot lineaments. Our data provide evidence for an age-progressive trend from 71 to 21 Ma. Assuming fixed hot spots, this makes possible a direct comparison to the Hawaiian-Emperor age progression and the most recent absolute plate motion (APM) model (WK08G) of Wessel and Kroenke (2008). We observe that for the Louisville seamount trail the measured ages are systematically older relative to both the WK08G model predictions and Hawaiian seamount ages, with offsets ranging up to 6 Myr. Taking into account the uncertainty about the duration of eruption and magmatic succession at individual Louisville volcanoes, these age offsets should be considered minimum estimates, as our sampling probably tended to recover the youngest lava flows. These large deviations point to either a contribution of inter-hot spot motion between the Louisville and Hawaiian hot spots or to a more easterly location of the Louisville hot spot than the one inferred in the WK08G model. Both scenarios are investigated in this paper, whereby the more eastern hot spot location (52.0°S, 134.5°W versus 52.4°S, 137.2°W) reduces the average age offset, but still results in a relatively large maximum offset of 3.7 Myr. When comparing the new ages to the APM models (S04P, S04G) by Steinberger et al. (2004) that attempt to compensate for the motion of hot spots in the Pacific (Hawaii) or globally (Hawaii, Louisville, Reunion and Walvis), the measured and predicted ages are more in agreement, showing only a maximum offset of 2.3 Myr with respect to the S04G model. At face value these more advanced APM models, which consider both plate and

Technical Note: Spot characteristic stability for proton pencil beam scanning.

Science.gov (United States)

Chen, Chin-Cheng; Chang, Chang; Moyers, Michael F; Gao, Mingcheng; Mah, Dennis

2016-02-01

The spot characteristics for proton pencil beam scanning (PBS) were measured and analyzed over a 16 month period, which included one major site configuration update and six cyclotron interventions. The results provide a reference to establish the quality assurance (QA) frequency and tolerance for proton pencil beam scanning. A simple treatment plan was generated to produce an asymmetric 9-spot pattern distributed throughout a field of 16 × 18 cm for each of 18 proton energies (100.0-226.0 MeV). The delivered fluence distribution in air was measured using a phosphor screen based CCD camera at three planes perpendicular to the beam line axis (x-ray imaging isocenter and up/down stream 15.0 cm). The measured fluence distributions for each energy were analyzed using in-house programs which calculated the spot sizes and positional deviations of the Gaussian shaped spots. Compared to the spot characteristic data installed into the treatment planning system, the 16-month averaged deviations of the measured spot sizes at the isocenter plane were 2.30% and 1.38% in the IEC gantry x and y directions, respectively. The maximum deviation was 12.87% while the minimum deviation was 0.003%, both at the upstream plane. After the collinearity of the proton and x-ray imaging system isocenters was optimized, the positional deviations of the spots were all within 1.5 mm for all three planes. During the site configuration update, spot positions were found to deviate by 6 mm until the tuning parameters file was properly restored. For this beam delivery system, it is recommended to perform a spot size and position check at least monthly and any time after a database update or cyclotron intervention occurs. A spot size deviation tolerance of spot positions were <2 mm at any plane up/down stream 15 cm from the isocenter.

[Effect of resin infiltration treatment on the colour of white spot lesions].

Science.gov (United States)

Zhao, Xiaoyi; Gao, Xuejun

2014-06-01

This study aimed to evaluate the effect of resin infiltration and fluoride solution on masking different demineralized white spot lesions by assessing color change. Artificial white spot lesions were produced on 60 human molars. Each sample had at least two enamel surfaces opened (named A and B). The samples were randomly divided into groups 1, 2, and 3 according to their time of demineralization (24, 48, and 72 h). After demineralization, the A spot of each sample was treated by resin infiltration. The B spot was treated with 0.1% fluoride solution daily for 30 days. After the remineralization of the B spot, resin infiltration was used again on the B spot of each sample. Color assessment was performed by a spectrophotometer in five distinct stages: baseline, after the production of artificial caries, after resin infiltration of A spots, after 30 days of fluoride solution treatment of B spots, and after resin infiltration of remineralized B spots. Before demineralization, the L* values of spots A and B in all groups were not significantly different (P > 0.05), whereas the L* values of spots A and B were significantly increased after demineralization. The L* values of A spots recovered significantly after treatment by resin infiltration (P 0.05) after fluoride treatment compared with that after demineralization. After resin infiltration on B spots, the L* values recovered but could not reach the baseline nor the level of A spots treated by resin infiltration only. Resin infiltration is a more effective treatment for masking white spot lesions than traditional fluoride treatment. The effect of masking white spot lesions has certain relationships with the degree of demineralization and activity of the lesion.

Modeling of low pressure plasma sources for microelectronics fabrication

International Nuclear Information System (INIS)

Agarwal, Ankur; Bera, Kallol; Kenney, Jason; Rauf, Shahid; Likhanskii, Alexandre

2017-01-01

Chemically reactive plasmas operating in the 1 mTorr–10 Torr pressure range are widely used for thin film processing in the semiconductor industry. Plasma modeling has come to play an important role in the design of these plasma processing systems. A number of 3-dimensional (3D) fluid and hybrid plasma modeling examples are used to illustrate the role of computational investigations in design of plasma processing hardware for applications such as ion implantation, deposition, and etching. A model for a rectangular inductively coupled plasma (ICP) source is described, which is employed as an ion source for ion implantation. It is shown that gas pressure strongly influences ion flux uniformity, which is determined by the balance between the location of plasma production and diffusion. The effect of chamber dimensions on plasma uniformity in a rectangular capacitively coupled plasma (CCP) is examined using an electromagnetic plasma model. Due to high pressure and small gap in this system, plasma uniformity is found to be primarily determined by the electric field profile in the sheath/pre-sheath region. A 3D model is utilized to investigate the confinement properties of a mesh in a cylindrical CCP. Results highlight the role of hole topology and size on the formation of localized hot-spots. A 3D electromagnetic plasma model for a cylindrical ICP is used to study inductive versus capacitive power coupling and how placement of ground return wires influences it. Finally, a 3D hybrid plasma model for an electron beam generated magnetized plasma is used to understand the role of reactor geometry on plasma uniformity in the presence of E  ×  B drift. (paper)

Modeling of low pressure plasma sources for microelectronics fabrication

Science.gov (United States)

Agarwal, Ankur; Bera, Kallol; Kenney, Jason; Likhanskii, Alexandre; Rauf, Shahid

2017-10-01

Chemically reactive plasmas operating in the 1 mTorr-10 Torr pressure range are widely used for thin film processing in the semiconductor industry. Plasma modeling has come to play an important role in the design of these plasma processing systems. A number of 3-dimensional (3D) fluid and hybrid plasma modeling examples are used to illustrate the role of computational investigations in design of plasma processing hardware for applications such as ion implantation, deposition, and etching. A model for a rectangular inductively coupled plasma (ICP) source is described, which is employed as an ion source for ion implantation. It is shown that gas pressure strongly influences ion flux uniformity, which is determined by the balance between the location of plasma production and diffusion. The effect of chamber dimensions on plasma uniformity in a rectangular capacitively coupled plasma (CCP) is examined using an electromagnetic plasma model. Due to high pressure and small gap in this system, plasma uniformity is found to be primarily determined by the electric field profile in the sheath/pre-sheath region. A 3D model is utilized to investigate the confinement properties of a mesh in a cylindrical CCP. Results highlight the role of hole topology and size on the formation of localized hot-spots. A 3D electromagnetic plasma model for a cylindrical ICP is used to study inductive versus capacitive power coupling and how placement of ground return wires influences it. Finally, a 3D hybrid plasma model for an electron beam generated magnetized plasma is used to understand the role of reactor geometry on plasma uniformity in the presence of E  ×  B drift.

Detecting Blind Spot By Using Ultrasonic Sensor

Directory of Open Access Journals (Sweden)

T. S. Ajay

2015-08-01

Full Text Available Safety remains a top concern for automobile industries and new-car shoppers. Detection of Blind Spots is a major concern for safety issues. So automobiles have been constantly updating their products with new technologies to detect blind spots so that they can add more safety to the vehicle and also reduce the road accidents. Almost 1.5 million people die in road accidents each year. Blind spot of an automobile is the region of the vehicle which cannot be observed properly while looking either through side or rear mirror view. To meet the above requirements this paper describes detecting blind spot by using ultrasonic sensor and controlling the direction of car by automatic steering. The technology embedded in the system is capable of automatically steer the vehicle away from an obstacle if the system determines that a collision is impending or if the vehicle is in the vicinity of our car.

El spot electoral negativo

Directory of Open Access Journals (Sweden)

Palma Peña-Jiménez

2011-01-01

Full Text Available l spot político tiene durante la campaña un objetivo final inequívoco: la consecución del voto favorable. Se dirige al cuerpo electoral a través de la televisión y de Internet, y presenta, en muchos casos, un planteamiento negativo, albergando mensajes destinados a la crítica frontal contra el adversario, más que a la exposición de propuestas propias. Este artículo se centra en el análisis del spot electoral negativo, en aquellas producciones audiovisuales construidas sin más causa que la reprobación del contrincante. Se trata de vídeos que, lejos de emplearse en difundir las potencialidades de la organización y las virtudes de su candidato –además de su programa electoral–, consumen su tiempo en descalificar al oponente mediante la transmisión de mensajes, muchas veces, ad hominem. Repasamos el planteamiento negativo del spot electoral desde su primera manifestación, que en España data de 1996, año de emisión del conocido como vídeo del dóberman, sin olvidar otros ejemplos que completan el objeto de estudio.

Fundus autofluorescence and optical coherence tomography of congenital grouped albinotic spots.

Science.gov (United States)

Kim, David Y; Hwang, John C; Moore, Anthony T; Bird, Alan C; Tsang, Stephen H

2010-09-01

The purpose of this study was to describe the findings of fundus autofluores-cence (FAF) and optical coherence tomography in a series of patients with congenital grouped albinotic spots. Three eyes of three patients with congenital grouped albinotic spots were evaluated with FAF and optical coherence tomography imaging to evaluate the nature of the albinotic spots. In all three eyes with congenital grouped albinotic spots, FAF imaging showed autofluorescent spots corresponding to the albinotic spots seen on stereo biomicroscopy. One eye also had additional spots detected on FAF imaging that were not visible on stereo biomicroscopy or color fundus photographs. Fundus autofluorescence imaging of the spots showed decreased general autofluorescence and decreased peripheral autofluorescence surrounding central areas of retained or increased autofluorescence. Optical coherence tomography showed a disruption in signal from the hyperreflective layer corresponding to the inner and outer segment junction and increased signal backscattering from the choroid in the area of the spots. Fluorescein angiography showed early and stable hyperfluorescence of the spots without leakage. In this case series, FAF showed decreased autofluorescence of the spots consistent with focal retinal pigment epithelium atrophy or abnormal material blocking normal autofluorescence and areas of increased autofluorescence suggesting retinal pigment epithelium dysfunction. The findings of optical coherence tomography and fluorescein angiography suggest photoreceptor and retinal pigment epithelium layer abnormalities. Fundus autofluorescence and optical coherence tomography are useful noninvasive diagnostic adjuncts that can aid in the diagnosis of congenital grouped albinotic spots, help determine extent of disease, and contribute to our understanding of its pathophysiology.

Investigation of kinematic demixing of polymer blend deuterated polystyrene (d-PS) and polyvinylmethylether (PVME) with neutron small angle scattering

International Nuclear Information System (INIS)

Yee Madeira, H.T.

1989-03-01

The scope of this work is the investigation of the system PV ME/d-PS by small angle neutron scattering (SANS). The measurements were done with a pinhole-camera and a high resolution double crystal diffractometer and covered the resolution range from 10 -3 to 3x10 -2 A -1 and 2x10 -5 to 6x10 -4 A -1 respectively. As a basis for these investigations the phase diagram of a PVME/d-PS mixture was measured with SANS. The spinodal for different curve between stable and demixing region was obtained. For PVME with molecular weights M ω =60000 and d-PS with M ω =215103 the critical point is at the concentration Φ=0.2. From the spinodal and the structure factor the Flory-Huggins parameter Χ could be extracted as a function of temperature. It was found that Χ=0 for T comp =135 0 C and Χ is independent of the molecular weight within the accuracy of the data, thus Χ may be associated with a local interaction parameter. The scattering experiments for the determination of the spinodal confirmed the mean-field behaviour of the critical scattering which was earlier found by Herkt-Maetzky and Schelten. Further, the time dependence of the structure factor in the miscibility gap was investigated. From the structure factors, specially from the position Q max of their maxima, a characteristic length was extracted. (orig./RB) [de

Effect of micrometric hot spots on surface temperature measurement and flux calculation in the middle and long infrared

International Nuclear Information System (INIS)

Delchambre, E; Counsell, G; Kirk, A

2009-01-01

The non-uniformity of the target temperature due to micrometric hot spots (Hermann et al 2004 Phys. Scr. T 111 98) is an explanation for the experimental fact that near-infrared measurements yield higher temperature values than mid-infrared measurements (Hildebrandt et al 2003 InfraMation 2003 Proc. (Las Vegas, USA, October 2003), Delchambre et al 2005 J. Nucl. Mater. 337-339 1069). The issue of micrometric hot spot disturbance in the surface temperature (T surf ) measurement and heat load calculation is addressed in this paper. The theoretical investigation at 3, 5 and 12 μm and experiments in the range 3.5-5 μm indicate that the surface state can play an important role in the non-uniform heating surface and consequently in the overestimation of the bulk temperature. The contribution of the hot spots to temperature measurements and flux calculations has been simulated at different wavelengths. Calculations show that (1) the overestimation of the bulk temperature decreases with the wavelength and (2) the overestimation depends on the temperature difference, ΔT, between the bulk and the micrometric hot spots. In addition, experiments have been carried out in order to compare the flux calculations at different wavelengths on different graphite (polished, dusty). The results obtained are very sensitive to the surface state pointing out the difficulties in improving the heat flux calculation model, since the surface state can change during the plasma discharges. This paper shows that the problem of non-homogenous surface temperature can be significantly diminished on working at longer wavelengths.

Computer simulations of laser hot spots and implosion symmetry kiniform phase plate experiments on Nova

International Nuclear Information System (INIS)

Peterson, R. R.; Lindman, E. L.; Delamater, N. D.; Magelssen, G. R.

2000-01-01

LASNEX computer code simulations have been performed for radiation symmetry experiments on the Nova laser with vacuum and gas-filled hohlraum targets [R. L. Kauffman et al., Phys. Plasmas 5, 1927 (1998)]. In previous experiments with unsmoothed laser beams, the symmetry was substantially shifted by deflection of the laser beams. In these experiments, laser beams have been smoothed with Kiniform Phase Plates in an attempt to remove deflection of the beams. The experiments have shown that this smoothing significantly improves the agreement with LASNEX calculations of implosion symmetry. The images of laser produced hot spots on the inside of the hohlraum case have been found to differ from LASNEX calculations, suggesting that some beam deflection or self-focusing may still be present or that emission from interpenetrating plasmas is an important component of the images. The measured neutron yields are in good agreement with simulations for vacuum hohlraums but are far different for gas-filled hohlraums. (c) 2000 American Institute of Physics

Damage tolerance reliability analysis of automotive spot-welded joints

International Nuclear Information System (INIS)

Mahadevan, Sankaran; Ni Kan

2003-01-01

This paper develops a damage tolerance reliability analysis methodology for automotive spot-welded joints under multi-axial and variable amplitude loading history. The total fatigue life of a spot weld is divided into two parts, crack initiation and crack propagation. The multi-axial loading history is obtained from transient response finite element analysis of a vehicle model. A three-dimensional finite element model of a simplified joint with four spot welds is developed for static stress/strain analysis. A probabilistic Miner's rule is combined with a randomized strain-life curve family and the stress/strain analysis result to develop a strain-based probabilistic fatigue crack initiation life prediction for spot welds. Afterwards, the fatigue crack inside the base material sheet is modeled as a surface crack. Then a probabilistic crack growth model is combined with the stress analysis result to develop a probabilistic fatigue crack growth life prediction for spot welds. Both methods are implemented with MSC/NASTRAN and MSC/FATIGUE software, and are useful for reliability assessment of automotive spot-welded joints against fatigue and fracture

Duodenal White Spots Mimicking Intestinal Candidiasis: Report of Case

Directory of Open Access Journals (Sweden)

Ozgur Turk

2015-12-01

Full Text Available Duodenal white spots are mentioned in these nonspecific lesions until recently. Although there is not enough studies about duedonal white spots yet; these lesions described in a separate syndrome. Here now we reported a case that we diagnosed multiple Duodenal white spots mimicking intestinal candidiasis. Clinical manifestation and endoscopic appearance of lesions gave rise to thought intestinal candidiasis histopathological examination revealed us several duodenitis. There was no evidence of fungal infection in PAS staining. Early after endoscopy patient took treatment of Lansoprozole at the 30 mg dose and bismuth salicylate. Patients compliant declined and control endoscopy exposed white duodenal spots cleared away three months later. Duodenal white spots are becoming to be designated as a separate disease even a syndrome. Etiology of duodenal white spots must be determined carefully during endoscopy. Sometimes it is difficult to make the correct diagnosis by appearance of lesion; in such cases histopathological examination can be useful both differential diagnosis of disease and determination of etiological factor. [J Contemp Med 2015; 5(4.000: 249-252

Finite Element and Experimental Study of Shunting in Resistance Spot Welding

DEFF Research Database (Denmark)

Seyyedian Choobi, M.; Nielsen, C. V.; Bay, N.

2015-01-01

This research is focused on one of the problems frequently encountered in spot welding in industry. In many applications several spot welds are made close to each other. The spots made after the first spot may become smaller in size due to shunt effect. A numerical and experimental study has been...... conducted to investigate the effect of shunting on nugget size in spot welding of HSLA steel sheets. Different cases with different spacing between weld spots have been examined. The nugget sizes have been measured by metallographic examination and have been compared with 3D finite element simulations...

Does contrast between eggshell ground and spot coloration affect egg rejection?

Science.gov (United States)

Dainson, Miri; Hauber, Mark E; López, Analía V; Grim, Tomáš; Hanley, Daniel

2017-08-01

Obligate avian brood parasitic species impose the costs of incubating foreign eggs and raising young upon their unrelated hosts. The most common host defence is the rejection of parasitic eggs from the nest. Both egg colours and spot patterns influence egg rejection decisions in many host species, yet no studies have explicitly examined the role of variation in spot coloration. We studied the American robin Turdus migratorius, a blue-green unspotted egg-laying host of the brown-headed cowbird Molothrus ater, a brood parasite that lays non-mimetic spotted eggs. We examined host responses to model eggs with variable spot coloration against a constant robin-mimetic ground colour to identify patterns of rejection associated with perceived contrast between spot and ground colours. By using avian visual modelling, we found that robins were more likely to reject eggs whose spots had greater chromatic (hue) but not achromatic (brightness) contrast. Therefore, egg rejection decision rules in the American robin may depend on the colour contrast between parasite eggshell spot and host ground coloration. Our study also suggests that egg recognition in relation to spot coloration, like ground colour recognition, is tuned to the natural variation of avian eggshell spot colours but not to unnatural spot colours.

Fast spot-based multiscale simulations of granular drainage

Energy Technology Data Exchange (ETDEWEB)

Rycroft, Chris H.; Wong, Yee Lok; Bazant, Martin Z.

2009-05-22

We develop a multiscale simulation method for dense granular drainage, based on the recently proposed spot model, where the particle packing flows by local collective displacements in response to diffusing"spots'" of interstitial free volume. By comparing with discrete-element method (DEM) simulations of 55,000 spheres in a rectangular silo, we show that the spot simulation is able to approximately capture many features of drainage, such as packing statistics, particle mixing, and flow profiles. The spot simulation runs two to three orders of magnitude faster than DEM, making it an appropriate method for real-time control or optimization. We demonstrateextensions for modeling particle heaping and avalanching at the free surface, and for simulating the boundary layers of slower flow near walls. We show that the spot simulations are robust and flexible, by demonstrating that they can be used in both event-driven and fixed timestep approaches, and showing that the elastic relaxation step used in the model can be applied much less frequently and still create good results.

Thermally-Driven Mantle Plumes Reconcile Hot-spot Observations

Science.gov (United States)

Davies, D.; Davies, J.

2008-12-01

Hot-spots are anomalous regions of magmatism that cannot be directly associated with plate tectonic processes (e.g. Morgan, 1972). They are widely regarded as the surface expression of upwelling mantle plumes. Hot-spots exhibit variable life-spans, magmatic productivity and fixity (e.g. Ito and van Keken, 2007). This suggests that a wide-range of upwelling structures coexist within Earth's mantle, a view supported by geochemical and seismic evidence, but, thus far, not reproduced by numerical models. Here, results from a new, global, 3-D spherical, mantle convection model are presented, which better reconcile hot-spot observations, the key modification from previous models being increased convective vigor. Model upwellings show broad-ranging dynamics; some drift slowly, while others are more mobile, displaying variable life-spans, intensities and migration velocities. Such behavior is consistent with hot-spot observations, indicating that the mantle must be simulated at the correct vigor and in the appropriate geometry to reproduce Earth-like dynamics. Thermally-driven mantle plumes can explain the principal features of hot-spot volcanism on Earth.

Long plasma source for heavy ion beam charge neutralization

International Nuclear Information System (INIS)

Efthimion, Philip C.; Gilson, Erik P.; Grisham, Larry; Davidson, Ronald C.; Grant Logan, Larry B.; Seidl, Peter A.; Waldron, William

2009-01-01

Plasmas are a source of unbound electrons for charge neutralizing intense heavy ion beams to focus them to a small spot size and compress their axial length. The plasma source should operate at low neutral pressures and without strong externally applied fields. To produce long plasma columns, sources based upon ferroelectric ceramics with large dielectric coefficients have been developed. The source utilizes the ferroelectric ceramic BaTiO 3 to form metal plasma. The drift tube inner surface of the Neutralized Drift Compression Experiment (NDCX) is covered with ceramic material. High voltage (∼8 kV) is applied between the drift tube and the front surface of the ceramics. A BaTiO 3 source comprised of five 20-cm-long sources has been tested and characterized, producing relatively uniform plasma in the 5x10 10 cm -3 density range. The source was integrated into the NDCX device for charge neutralization and beam compression experiments, and yielded current compression ratios ∼120. Present research is developing multi-meter-long and higher density sources to support beam compression experiments for high-energy-density physics applications.

At the border: the plasma membrane-cell wall continuum.

Science.gov (United States)

Liu, Zengyu; Persson, Staffan; Sánchez-Rodríguez, Clara

2015-03-01

Plant cells rely on their cell walls for directed growth and environmental adaptation. Synthesis and remodelling of the cell walls are membrane-related processes. During cell growth and exposure to external stimuli, there is a constant exchange of lipids, proteins, and other cell wall components between the cytosol and the plasma membrane/apoplast. This exchange of material and the localization of cell wall proteins at certain spots in the plasma membrane seem to rely on a particular membrane composition. In addition, sensors at the plasma membrane detect changes in the cell wall architecture, and activate cytoplasmic signalling schemes and ultimately cell wall remodelling. The apoplastic polysaccharide matrix is, on the other hand, crucial for preventing proteins diffusing uncontrollably in the membrane. Therefore, the cell wall-plasma membrane link is essential for plant development and responses to external stimuli. This review focuses on the relationship between the cell wall and plasma membrane, and its importance for plant tissue organization. © The Author 2015. Published by Oxford University Press on behalf of the Society for Experimental Biology. All rights reserved. For permissions, please email: journals.permissions@oup.com.

Measurement of PuO2 spot in the mixed-oxide fuels

International Nuclear Information System (INIS)

Yokosuka, Yoshifumi; Kaneda, Kenichiro; Ishikawa, Eiji; Nakajima, Katsuaki; Kashima, Sadamitsu

1974-01-01

The homogeneity of mixed-oxide fuel is evaluated with the maximum diameter of PuO 2 spots. PuO 2 spot distribution is influenced by fuel production process and raw materials used. Analytical measurement of the PuO 2 spot distribution was carried out. α-autoradiograph was taken with nitrocellulose film as a detector. The film was exposed for 15 and 30 minutes to the sample pellets, and etched in 10% NaOH for 2 minutes at 60 0 C. Measurement of PuO 2 spots was performed manually with a projector. PuO 2 spot distribution was measured. There is no difference of spot distribution owing to the location in a pellet. However some discrepancy exists in spot number and maximum diameter between surface and inner part. This phenomenon is explained by considering that the diffusion on surface is more effective than in inner part in sintering process. Three pellets were taken out from a lot at random, and α-autoradiograph was taken longitudinally with a pellet and transversely with the others. PuO 2 spot number counted from three autoradiographs was about 150/cm 2 , and the standard deviation was about 1.5. No difference was observed among them. Concerning the influence of mixing method on PuO 2 spot formation, three methods were examined; ball mill mixing (with and without lining) and Kneader mixing. Kneader mixing gave the worst results in maximum spot diameter and spot distribution range. (Tai, I.)

Hot spots on Tc-99m MAA perfusion lung scan

International Nuclear Information System (INIS)

Lim, Seok Tae; Sohn, Myung Hee

2001-01-01

A 61 year-old woman underwent perfusion and inhalation lung scan for the evaluation of pulmonary thromboembolism. Tc-99m MAA perfusion lung scan showed multiple round hot spots in both lung fields. Tc-99m DTPA aerosol inhalation lung scan and chest radiography taken at the same time showed normal findings. A repeated perfusion lung scan taken 24 hours later demonstrated no abnormalities. Hot spots on perfusion lung scan can be caused by microsphere clumping due to faulty injection technique by radioactive embolization from upper extremity thrombophlebitis after injection. Focal hot spots can signify zones of atelectasis, where the hot spots probably represent a failure of hypoxic vasoconstriction. Artifactual hot spots due to microsphere clumping usually appear to be round and in peripheral location, and the lesions due to a loss of hypoxic vasoconstriction usually appear to be hot uptakes having linear borders. Although these artifactual hot spots have been well-known, we rarely encounter them. This report presents a case with artifactual hot spots due to microsphere clumping on Tc-99m MAA perfusion lung scan

Subsurface plasma in beam of continuous CO2-laser

Science.gov (United States)

Danytsikov, Y. V.; Dymshakov, V. A.; Lebedev, F. V.; Pismennyy, V. D.; Ryazanov, A. V.

1986-03-01

Experiments performed at the Institute of Atomic Energy established the conditions for formation of subsurface plasma in substances by laser radiation and its characteristics. A quasi-continuous CO2 laser emitting square pulses of 0.1 to 1.0 ms duration and 1 to 10 kW power as well as a continuous CO2 laser served as radiation sources. Radiation was focused on spots 0.1 to 0.5 mm in diameter and maintained at levels ensuring constant power density during the interaction time, while the temperature of the target surface was measured continuously. Metals, graphite and dielectric materials were tested with laser action taking place in air N2 + O2 mixtures, Ar or He atmosphere under pressures of 0.01 to 1.0 atm. Data on radiation intensity thresholds for evaporation and plasma formation were obtained. On the basis of these thresholds, combined with data on energy balance and the temperature profile in plasma layers, a universal state diagram was constructed for subsurface plasma with nonquantified surface temperature and radiation intensity coordinates.

Sugarbeet leaf spot disease (Cercospora beticola Sacc.)dagger.

Science.gov (United States)

Weiland, John; Koch, Georg

2004-05-01

SUMMARY Leaf spot disease caused by Cercospora beticola Sacc. is the most destructive foliar pathogen of sugarbeet worldwide. In addition to reducing yield and quality of sugarbeet, the control of leaf spot disease by extensive fungicide application incurs added costs to producers and repeatedly has selected for fungicide-tolerant C. beticola strains. The genetics and biochemistry of virulence have been examined less for C. beticola as compared with the related fungi C. nicotianae, C. kikuchii and C. zeae-maydis, fungi to which the physiology of C. beticola is often compared. C. beticola populations generally are not characterized as having race structure, although a case of race-specific resistance in sugarbeet to C. beticola has been reported. Resistance currently implemented in the field is quantitatively inherited and exhibits low to medium heritability. Cercospora beticola Sacc.; Kingdom Fungi, Subdivision Deuteromycetes, Class Hyphomycetes, Order Hyphales, Genus Cercospora. Circular, brown to red delimited spots with ashen-grey centre, 0.5-6 mm diameter; dark brown to black stromata against grey background; pale brown unbranched sparingly septate conidiophores, hyaline acicular conidia, multiseptate, from 2.5 to 4 microm wide and 50-200 microm long. Propagative on Beta vulgaris and most species of Beta. Reported on members of the Chenopodiaceae and on Amaranthus. Disease symptoms: Infected leaves and petioles of B. vulgaris exhibit numerous circular leaf spots that coalesce in severe cases causing complete leaf collapse. Dark specks within a grey spot centre are characteristic for the disease. Older leaves exhibit a greater number of lesions with larger spot diameter. During the latter stage of severe epiphytotics, new leaf growth can be seen emerging from the plant surrounded by prostrate, collapsed leaves. Fungicides in the benzimidazole and triazole class as well as organotin derivatives and strobilurins have successfully been used to control Cercospora

Justifications shape ethical blind spots.

Science.gov (United States)

Pittarello, Andrea; Leib, Margarita; Gordon-Hecker, Tom; Shalvi, Shaul

2015-06-01

To some extent, unethical behavior results from people's limited attention to ethical considerations, which results in an ethical blind spot. Here, we focus on the role of ambiguity in shaping people's ethical blind spots, which in turn lead to their ethical failures. We suggest that in ambiguous settings, individuals' attention shifts toward tempting information, which determines the magnitude of their lies. Employing a novel ambiguous-dice paradigm, we asked participants to report the outcome of the die roll appearing closest to the location of a previously presented fixation cross on a computer screen; this outcome would determine their pay. We varied the value of the die second closest to the fixation cross to be either higher (i.e., tempting) or lower (i.e., not tempting) than the die closest to the fixation cross. Results of two experiments revealed that in ambiguous settings, people's incorrect responses were self-serving. Tracking participants' eye movements demonstrated that people's ethical blind spots are shaped by increased attention toward tempting information. © The Author(s) 2015.

Relativistic self-focusing of intense laser beam in thermal collisionless quantum plasma with ramped density profile

Directory of Open Access Journals (Sweden)

S. Zare

2015-04-01

Full Text Available Propagation of a Gaussian x-ray laser beam has been analyzed in collisionless thermal quantum plasma with considering a ramped density profile. In this density profile due to the increase in the plasma density, an earlier and stronger self-focusing effect is noticed where the beam width oscillates with higher frequency and less amplitude. Moreover, the effect of the density profile slope and the initial plasma density on the laser propagation has been studied. It is found that, by increasing the initial density and the ramp slope, the laser beam focuses faster with less oscillation amplitude, smaller laser spot size and more oscillations. Furthermore, a comparison is made among the laser self-focusing in thermal quantum plasma, cold quantum plasma and classical plasma. It is realized that the laser self-focusing in the quantum plasma becomes stronger in comparison with the classical regime.

The sweet spots in human communication.

Science.gov (United States)

Salem, Philip

2011-07-01

In baseball, the sweet spot is a special place on a bat where the batter can hit the ball with the most power. It is the place where the performances of the batter and pitcher collide with maximum effect. It is the place where the dynamic tension between opponents leads to transformation. The dynamic tension in all living systems is between similarity and difference. Chaos and complexity scholars recognized this tension as amounts of information. When the amounts of information were high, but not too high, the system moved to the edge of chaos, to the complexity regime, to strange attractors, or to chaos, depending on the model. The sweet spot is that range of relative variety, just the proper mix of similarity and difference, leading to transformation. This essay contains a model of human communication as an emergent social process with its own sweet spots. The essay also includes a description of current literature highlighting tensions between similarity and difference, and there is an exploration of the potential to move from one basin of attraction to another. The primary constraints on finding communication sweet spots are paradigmatic - adopting a process orientation, discovering the proper parameters, bracketing sequences to define initial conditions, and understanding the strengths and weaknesses of various modeling techniques.

Coupling effects of refractive index discontinuity, spot size and spot location on the deflection sensitivity of optical-lever based atomic force microscopy

International Nuclear Information System (INIS)

Liu Yu; Yang Jun

2008-01-01

Atomic force microscopy (AFM) plays an essential role in nanotechnology and nanoscience. The recent advances of AFM in bionanotechnology include phase imaging of living cells and detection of biomolecular interactions in liquid biological environments. Deflection sensitivity is a key factor in both imaging and force measurement, which is significantly affected by the coupling effects of the refractive index discontinuity between air, the glass window and the liquid medium, and the laser spot size and spot location. The effects of both the spot size and the spot location on the sensitivity are amplified by the refractive index discontinuity. The coupling effects may govern a transition of the deflection sensitivity from enhancement to degradation. It is also found that there is a critical value for the laser spot size, above which the deflection sensitivity is mainly determined by the refractive index of the liquid. Experimental results, in agreement with theoretical predication, elucidate the coupling effects

Characterization of aluminum x-pinch plasmas driven by the 0.5 TW Lion accelerator

International Nuclear Information System (INIS)

Qi, N.; Hammer, D.A.; Kalantantar, D.H.; Noonan, W.A.; Rondeau, G.; Workman, J.B.; Richardson, M.C.

1989-01-01

The x-pinch, obtained by crossing two fine wires at one or more points as the load for the 0.5 TW Lion accelerator, has been used as a bright x-ray source. High density and temperature hot spots are observed at the crossing point(s). From these hot spots, an intense, spatially confined burst of x-rays is emitted which can serve as a pump for resonant photo-pumping lasers. The authors present experimental results concerning the radiation emission using Al x-pinches. The optimum mass loading for different ionization stages of Al ions and the total x-ray energy yields are examined. The density and temperature of the plasma and the size of the hot spots are measures. Based upon the results of these experiments, the authors evaluate resonant photopumping schemes such as those involving Be-like ions, using the Al x-pinch emission as the pump source

Sowing rates for reforestation by the seed-spotting method

Science.gov (United States)

Gilbert H. Schubert; Harry A. Fowells

1964-01-01

Presents guides to determine the number of seeds to sow per spot and the number of spots required per acre to obtain acceptable stocking. Based on theoretical probabilities, these guides were found to be reasonably close to actual field results When the probability-of-success was at least 55 percent. To compensate for lower actual stocking, increase the number of spots...

Simulation of eye-tracker latency, spot size, and ablation pulse depth on the correction of higher order wavefront aberrations with scanning spot laser systems.

Science.gov (United States)

Bueeler, Michael; Mrochen, Michael

2005-01-01

The aim of this theoretical work was to investigate the robustness of scanning spot laser treatments with different laser spot diameters and peak ablation depths in case of incomplete compensation of eye movements due to eye-tracker latency. Scanning spot corrections of 3rd to 5th Zernike order wavefront errors were numerically simulated. Measured eye-movement data were used to calculate the positioning error of each laser shot assuming eye-tracker latencies of 0, 5, 30, and 100 ms, and for the case of no eye tracking. The single spot ablation depth ranged from 0.25 to 1.0 microm and the spot diameter from 250 to 1000 microm. The quality of the ablation was rated by the postoperative surface variance and the Strehl intensity ratio, which was calculated after a low-pass filter was applied to simulate epithelial surface smoothing. Treatments performed with nearly ideal eye tracking (latency approximately 0) provide the best results with a small laser spot (0.25 mm) and a small ablation depth (250 microm). However, combinations of a large spot diameter (1000 microm) and a small ablation depth per pulse (0.25 microm) yield the better results for latencies above a certain threshold to be determined specifically. Treatments performed with tracker latencies in the order of 100 ms yield similar results as treatments done completely without eye-movement compensation. CONCWSIONS: Reduction of spot diameter was shown to make the correction more susceptible to eye movement induced error. A smaller spot size is only beneficial when eye movement is neutralized with a tracking system with a latency <5 ms.

White-centred retinal haemorrhages (Roth spots).

OpenAIRE

Ling, R.; James, B.

1998-01-01

Roth spots (white-centred retinal haemorrhages) were classically described as septic emboli lodged in the retina of patients with subacute bacterial endocarditis. Indeed many have considered Roth spots pathognomonic for this condition. More recent histological evidence suggests, however, that they are not foci of bacterial abscess. Instead, they are nonspecific and may be found in many other diseases. A review of the histology and the pathogenesis of these white-centred haemorrhages will be p...

Technical Note: Spot characteristic stability for proton pencil beam scanning

Energy Technology Data Exchange (ETDEWEB)

Chen, Chin-Cheng, E-mail: chen.ccc@gmail.com; Chang, Chang; Mah, Dennis [ProCure Treatment Center, Somerset, New Jersey 08873 (United States); Moyers, Michael F. [ProCure Treatment Center, Somerset, New Jersey 08873 and Shanghai Proton and Heavy Ion Center, Shanghai 201321 (China); Gao, Mingcheng [CDH Proton Center, Warrenville, Illinois 60555 (United States)

2016-02-15

Purpose: The spot characteristics for proton pencil beam scanning (PBS) were measured and analyzed over a 16 month period, which included one major site configuration update and six cyclotron interventions. The results provide a reference to establish the quality assurance (QA) frequency and tolerance for proton pencil beam scanning. Methods: A simple treatment plan was generated to produce an asymmetric 9-spot pattern distributed throughout a field of 16 × 18 cm for each of 18 proton energies (100.0–226.0 MeV). The delivered fluence distribution in air was measured using a phosphor screen based CCD camera at three planes perpendicular to the beam line axis (x-ray imaging isocenter and up/down stream 15.0 cm). The measured fluence distributions for each energy were analyzed using in-house programs which calculated the spot sizes and positional deviations of the Gaussian shaped spots. Results: Compared to the spot characteristic data installed into the treatment planning system, the 16-month averaged deviations of the measured spot sizes at the isocenter plane were 2.30% and 1.38% in the IEC gantry x and y directions, respectively. The maximum deviation was 12.87% while the minimum deviation was 0.003%, both at the upstream plane. After the collinearity of the proton and x-ray imaging system isocenters was optimized, the positional deviations of the spots were all within 1.5 mm for all three planes. During the site configuration update, spot positions were found to deviate by 6 mm until the tuning parameters file was properly restored. Conclusions: For this beam delivery system, it is recommended to perform a spot size and position check at least monthly and any time after a database update or cyclotron intervention occurs. A spot size deviation tolerance of <15% can be easily met with this delivery system. Deviations of spot positions were <2 mm at any plane up/down stream 15 cm from the isocenter.

Technical Note: Spot characteristic stability for proton pencil beam scanning

International Nuclear Information System (INIS)

Chen, Chin-Cheng; Chang, Chang; Mah, Dennis; Moyers, Michael F.; Gao, Mingcheng

2016-01-01

Purpose: The spot characteristics for proton pencil beam scanning (PBS) were measured and analyzed over a 16 month period, which included one major site configuration update and six cyclotron interventions. The results provide a reference to establish the quality assurance (QA) frequency and tolerance for proton pencil beam scanning. Methods: A simple treatment plan was generated to produce an asymmetric 9-spot pattern distributed throughout a field of 16 × 18 cm for each of 18 proton energies (100.0–226.0 MeV). The delivered fluence distribution in air was measured using a phosphor screen based CCD camera at three planes perpendicular to the beam line axis (x-ray imaging isocenter and up/down stream 15.0 cm). The measured fluence distributions for each energy were analyzed using in-house programs which calculated the spot sizes and positional deviations of the Gaussian shaped spots. Results: Compared to the spot characteristic data installed into the treatment planning system, the 16-month averaged deviations of the measured spot sizes at the isocenter plane were 2.30% and 1.38% in the IEC gantry x and y directions, respectively. The maximum deviation was 12.87% while the minimum deviation was 0.003%, both at the upstream plane. After the collinearity of the proton and x-ray imaging system isocenters was optimized, the positional deviations of the spots were all within 1.5 mm for all three planes. During the site configuration update, spot positions were found to deviate by 6 mm until the tuning parameters file was properly restored. Conclusions: For this beam delivery system, it is recommended to perform a spot size and position check at least monthly and any time after a database update or cyclotron intervention occurs. A spot size deviation tolerance of <15% can be easily met with this delivery system. Deviations of spot positions were <2 mm at any plane up/down stream 15 cm from the isocenter

SPOT: How good for geology? A comparison with LANDSAT MSS

Science.gov (United States)

Sesoeren, A.

1986-12-01

Geological interpretation possibilities of SPOT MSS and LANDSAT MSS positive prints enlarged to the same scale were compared, using as a test area part of the Jebel Amour (Algeria). The SPOT imagery offers many advantages, filling the gap between remote sensing from space and aerial photography. The best results by visual interpretation are obtained in combining SPOT for the required details with LANDSAT for the synoptic veiw. Further improvements are expected from the use of SPOT stereo-pairs.

Reply to the ''Comment on 'The significance of the distribution of hot spots on the interpretation of laser-produced plasma experiments' ''

International Nuclear Information System (INIS)

Arad, B.; Eliezer, S.

1979-01-01

We disagree with the conclusion reached by Goel, Gupta, and Bhatnagar that the effect of hot spots is not significant in analyzing scaling laws using transformed variables. We believe they have overlooked the main points of our analysis

Meteorology of Jupiter's Equatorial Hot Spots and Plumes from Cassini

Science.gov (United States)

Choi, David Sanghun; Showman, Adam P.; Vasavada, Ashwin R.; Simon-Miller, Amy A.

2013-01-01

We present an updated analysis of Jupiter's equatorial meteorology from Cassini observations. For two months preceding the spacecraft's closest approach, the Imaging Science Subsystem (ISS) onboard regularly imaged the atmosphere. We created time-lapse movies from this period in order to analyze the dynamics of equatorial hot spots and their interactions with adjacent latitudes. Hot spots are relatively cloud-free regions that emit strongly at 5 lm; improved knowledge of these features is crucial for fully understanding Galileo probe measurements taken during its descent through one. Hot spots are quasistable, rectangular dark areas on visible-wavelength images, with defined eastern edges that sharply contrast with surrounding clouds, but diffuse western edges serving as nebulous boundaries with adjacent equatorial plumes. Hot spots exhibit significant variations in size and shape over timescales of days and weeks. Some of these changes correspond with passing vortex systems from adjacent latitudes interacting with hot spots. Strong anticyclonic gyres present to the south and southeast of the dark areas appear to circulate into hot spots. Impressive, bright white plumes occupy spaces in between hot spots. Compact cirrus-like 'scooter' clouds flow rapidly through the plumes before disappearing within the dark areas. These clouds travel at 150-200 m/s, much faster than the 100 m/s hot spot and plume drift speed. This raises the possibility that the scooter clouds may be more illustrative of the actual jet stream speed at these latitudes. Most previously published zonal wind profiles represent the drift speed of the hot spots at their latitude from pattern matching of the entire longitudinal image strip. If a downward branch of an equatorially-trapped Rossby wave controls the overall appearance of hot spots, however, the westward phase velocity of the wave leads to underestimates of the true jet stream speed.

Hot spots effect on infrared spectral luminance emitted by carbon under plasma particles impact

International Nuclear Information System (INIS)

Delchambre, E.; Reichle, R.; Mitteau, R.; Missirlian, M.; Gobin, R.

2004-01-01

During the last Tore Supra campaigns, an anomalous deformation in the near infrared spectrum of radiation has been observed on neutralizer underneath the Toroidal Pumped Limiter (TPL) on which we observed the growth of carbon layer. The consequence is the difficulty to asses the surface temperature of the components and the power loaded. Laboratory experiment has been performed, using an Electron Cyclotron Resonance (ECR) ions source, to reproduce, characterize and explain this phenomenon. The luminance emitted by Carbon Fibre Composite (CFC) and pyrolytic graphite, have been observed under 95 keV of H+ bombardments. The amplitude of the deformation was found to depend on the type of material used and the power density of the incident power loaded. This paper presents the possible hot spots explanation. The experimental luminance deformation is reproduced and these results are validated using a thermal model of dust in radiate equilibrium. (authors)

KFC Server: interactive forecasting of protein interaction hot spots.

Science.gov (United States)

Darnell, Steven J; LeGault, Laura; Mitchell, Julie C

2008-07-01

The KFC Server is a web-based implementation of the KFC (Knowledge-based FADE and Contacts) model-a machine learning approach for the prediction of binding hot spots, or the subset of residues that account for most of a protein interface's; binding free energy. The server facilitates the automated analysis of a user submitted protein-protein or protein-DNA interface and the visualization of its hot spot predictions. For each residue in the interface, the KFC Server characterizes its local structural environment, compares that environment to the environments of experimentally determined hot spots and predicts if the interface residue is a hot spot. After the computational analysis, the user can visualize the results using an interactive job viewer able to quickly highlight predicted hot spots and surrounding structural features within the protein structure. The KFC Server is accessible at http://kfc.mitchell-lab.org.

Plasma proteomic study in patients with high altitude pulmonary edema (HAPE

Directory of Open Access Journals (Sweden)

Yong-jun LUO

2012-01-01

Full Text Available Objective  To investigate the differential expressions of protein in the plasma proteome in patients suffering from high altitude pulmonary edema (HAPE and their implications. Methods  The plasmas of six HAPE patients and six healthy controls were studied. The high-abundant proteins in the plasma were removed. The low-abundant proteins in the plasma/serum were segregated by 2-DE. MALDI-TOF/MS was adopted to measure the peptide fingerprints after the differential protein spots were digested by enzymes. Comparison and analysis were made in the GenBank. Results  The immunoglobulin K1 light chain, serum transferrin protein precursor, and α-trypsin inhibitor heavy chain-related protein expressions were upregulated in HAPE patients compared with the control group. However the human fibrin glue coagulation protein 3 was down-regulated. Conclusion  The differential expression of the above four proteins in the plasma of HAPE patients may be related to the occurrence of HAPE and can be used as the target point for the prediction of HAPE.

Reliability of copper based alloys for electric resistance spot welding

International Nuclear Information System (INIS)

Jovanovicj, M.; Mihajlovicj, A.; Sherbedzhija, B.

1977-01-01

Durability of copper based alloys (B-5 and B-6) for electric resistance spot-welding was examined. The total amount of Be, Ni and Zr was up to 2 and 1 wt.% respectively. Good durability and satisfactory quality of welded spots were obtained in previous laboratory experiments carried out on the fixed spot-welding machine of an industrial type (only B-5 alloy was examined). Electrodes made of both B-5 and B-6 alloy were tested on spot-welding grips and fixed spot-welding machines in Tvornica automobila Sarajevo (TAS). The obtained results suggest that the durability of electrodes made of B-5 and B-6 alloys is more than twice better than of that used in TAS

Acute infectious purpura fulminans due to probable spotted fever

Directory of Open Access Journals (Sweden)

A Kundavaram

2014-01-01

Full Text Available Purpura fulminans (PF is associated with several infections, most notably with meningococcus, staphylococcus, and streptococcus infections. However, there are few reports of association of this entity with spotted fever from India. We report the case of a 55-year-old man who presented with fever, headache, and myalgia. On the seventh day of fever he developed nonblanching purple hemorrhagic purpura on the trunk and most prominently on the extremities consistent with purpura fulminans. Immunofluorescent assay confirmed the diagnosis of spotted fever. PF though common with rocky mountain spotted fever (RMSF is rarely seen in association with Indian tick typhus, the usual cause of spotted fever in India.

Wood ant nests as hot spots of carbon dioxide production and cold spots of methane oxidation in temperate forests

Czech Academy of Sciences Publication Activity Database

Jílková, Veronika; Picek, T.; Cajthaml, Tomáš; Frouz, Jan

2016-01-01

Roč. 18, April (2016), EGU2016-4634 ISSN 1607-7962. [European Geosciences Union General Assembly 2016. 17.04.2016-22.04.2016, Vienna] Institutional support: RVO:60077344 ; RVO:61388971 Keywords : wood ant nests * hot spots of carbon dioxide production * cold spots of methane oxidation * temperate forests Subject RIV: DF - Soil Science

Influence of cross-breeding of native breed sows of Zlotnicka spotted ...

African Journals Online (AJOL)

The aim of this study was the estimation of the cross-breeding influence of Zlotnicka spotted sows with boars of polish large white and Duroc breeds on carcass traits of fatteners. 50 pigs were divided into four groups: Zlotnicka spotted (ZS), Zlotnicka spotted x polish large white (ZS x PLW), Zlotnicka spotted x Duroc (ZS x D) ...

Transition Heat Transfer Modeling Based on the Characteristics of Turbulent Spots

Science.gov (United States)

Simon, Fred; Boyle, Robert

1998-01-01

While turbulence models are being developed which show promise for simulating the transition region on a turbine blade or vane, it is believed that the best approach with the greatest potential for practical use is the use of models which incorporate the physics of turbulent spots present in the transition region. This type of modeling results in the prediction of transition region intermittency which when incorporated in turbulence models give a good to excellent prediction of the transition region heat transfer. Some models are presented which show how turbulent spot characteristics and behavior can be employed to predict the effect of pressure gradient and Mach number on the transition region. The models predict the spot formation rate which is needed, in addition to the transition onset location, in the Narasimha concentrated breakdown intermittency equation. A simplified approach is taken for modeling turbulent spot growth and interaction in the transition region which utilizes the turbulent spot variables governing transition length and spot generation rate. The models are expressed in terms of spot spreading angle, dimensionless spot velocity, dimensionless spot area, disturbance frequency and Mach number. The models are used in conjunction with a computer code to predict the effects of pressure gradient and Mach number on the transition region and compared with VKI experimental turbine data.

Laser Spot Center Detection and Comparison Test

Science.gov (United States)

Zhu, Jun; Xu, Zhengjie; Fu, Deli; Hu, Cong

2018-04-01

High efficiency and precision of the pot center detection are the foundations of avionics instrument navigation and optics measurement basis for many applications. It has noticeable impact on overall system performance. Among them, laser spot detection is very important in the optical measurement technology. In order to improve the low accuracy of the spot center position, the algorithm is improved on the basis of the circle fitting. The pretreatment is used by circle fitting, and the improved adaptive denoising filter for TV repair technology can effectively improves the accuracy of the spot center position. At the same time, the pretreatment and de-noising can effectively reduce the influence of Gaussian white noise, which enhances the anti-jamming capability.

Resistance in winter barley against Ramularia leaf spot

DEFF Research Database (Denmark)

Hjortshøj, Rasmus Lund

Ramularia leaf spot is an emerging disease in barley caused by R. collo-cygni. At present little is known about the resistance mechanisms carried out by the host plant to avoid disease development. Nor is the lifecycle of the fungus or its populations structure fully understood. To gain insight....... fulvum-tomato and S. tritici-wheat in order to find modelsystems to enhance interpretation of results from R. collo-cygni-barley interaction. Results from the mapping showed that resistance to Ramularia leaf spot is controlled by a number of QTL’s, some of which co-locate with other physiological traits....... The populations further segregated for physiological leaf spots, a phenomenon related to the leaf damage imposed by Rubellin, although, resistance to physiological leafspots appeared to come from the Ramularia leaf spot susceptible parent. The toxin assay further supported this result as the genotypes susceptible...

A Seemingly Simple Task: Filling a Solenoid Volume in Vacuum with Dense Plasma

International Nuclear Information System (INIS)

Anders, Andre; Kauffeldt, Marina; Roy, Prabir; Oks, Efim

2010-01-01

Space-charge neutralization of a pulsed, high-current ion beam is required to compress and focus the beam on a target for warm dense matter physics or heavy ion fusion experiments. We described attempts to produce dense plasma in and near the final focusing solenoid through which the ion beam travels, thereby providing an opportunity for the beam to acquire the necessary charge-compensating electrons. Among the options are plasma injection from four pulsed vacuum arc sources located outside the solenoid, and using a high current (> 4 kA) pulsed vacuum arc plasma from a ring cathode near the edge of the solenoid. The plasma distribution is characterized by photographic means and by an array of movable Langmuir probes. The plasma is produced at several cathode spots distributed azimuthally on the ring cathode. Beam neutralization and compression are accomplished, though issues of density, uniformity, and pulse-to-pulse reproducibly remain to be solved.

Thermonuclear plasma physic: inertial confinement fusion

International Nuclear Information System (INIS)

Bayer, Ch.; Juraszek, D.

2001-01-01

Inertial Confinement Fusion (ICF) is an approach to thermonuclear fusion in which the fuel contained in a spherical capsule is strongly compressed and heated to achieve ignition and burn. The released thermonuclear energy can be much higher than the driver energy, making energetic applications attractive. Many complex physical phenomena are involved by the compression process, but it is possible to use simple analytical models to analyze the main critical points. We first determine the conditions to obtain fuel ignition. High thermonuclear gains are achieved if only a small fraction of the fuel called hot spot is used to trigger burn in the main fuel compressed on a low isentrope. A simple hot spot model will be described. The high pressure needed to drive the capsule compression are obtained by the ablation process. A simple Rocket model describe the main features of the implosion phase. Several parameters have to be controlled during the compression: irradiation symmetry, hydrodynamical stability and when the driver is a laser, the problems arising from interaction of the EM wave with the plasma. Two different schemes are examined: Indirect Drive which uses X-ray generated in a cavity to drive the implosion and the Fast Ignitor concept using a ultra intense laser beam to create the hot spot. At the end we present the Laser Megajoule (LMJ) project. LMJ is scaled to a thermonuclear gain of the order of ten. (authors)

Degradation of Albumin on Plasma-Treated Polystyrene by Soft X-ray Exposure

Directory of Open Access Journals (Sweden)

Nina Recek

2016-06-01

Full Text Available Thin films of human serum albumin (HSA were immobilized on polystyrene (PS substrates previously functionalized either with polar or nonpolar functional groups. The functionalization was performed by treatment with cold gaseous plasma created in pure oxygen and tetrafluoromethane (CF4 plasmas, respectively. Samples were examined with soft X-rays in the photon energy range of 520 to 710 eV in the ANTARES beam line at SOLEIL Synchrotron. NEXAFS spectra of O K-edge and F K-edge were collected at different spots of the sample, and measurements at each spot were repeated many times. A strong degradation of the HSA protein was observed. The weakly irradiated samples exhibited strong absorption at 531.5 eV associated with the O 1s→π*amide transitions, and a broad non distinctive peak at 540 eV was attributed to the O 1s→σ*C–O transitions. Both peaks decreased with increasing irradiation time until they were completely replaced by a broad non-distinctive peak at around 532 eV, indicating the destruction of the original protein conformation. The shortage of the amide groups indicated breakage of the peptide bonds.

Hot spot model of MagLIF implosions: Nernst term effect on magnetic flux losses

Science.gov (United States)

Garcia Rubio, Fernando; Sanz Recio, Javier; Betti, Riccardo

2016-10-01

An analytical model of a collisional plasma being compressed by a cylindrical liner is proposed and solved in a magnetized liner inertial fusion-like context. The implosion is assumed to be isobaric, and the magnetic diffusion is confined to a thin layer near the liner. Both unmagnetized and magnetized plasma cases are considered. The model reduces to a system of two partial differential equations for temperature and magnetic field. Special attention is given to the effect of the Nernst term on the evolution of the magnetic field. Scaling laws for temperature, magnetic field, hot spot mass increase and magnetic field losses are obtained. The temperature and magnetic field spatial profiles tend to a self-similar state. It is found that when the Nernst term is taken into account, the magnetic field is advected towards the liner, and the magnetic flux losses are independent of the magnetic Lewis number. Research supported by the Spanish Ministerio de Economía y Competitividad, Project No. ENE2014-54960R. Acknowledgements to the Laboratory of Laser Energetics (Rochester) for its hospitality.

Stimulated Brillouin backscattering losses in weakly inhomogeneous laser-produced plasmas

International Nuclear Information System (INIS)

Eidmann, K.; Brederlow, G.; Brodmann, R.; Petsch, R.; Sigel, R.; Tsarkiris, G.; Volk, R.; Witkowski, S.

1979-02-01

Studies of the reflection from a plane solid target plasma produced with a 1TW iodine laser (lambda = 1.3μm) at pulse durations of 300 ps are presented. The specularly reflected and the backscattered light was observed separately at different angles of incidence, intensities and spot sizes (up to 400 μm). Stimulated Brillouin scattering was identified as the main mechanism for backscattering with saturation at 20 - 30% reflection. (orig.) [de

Timing of Occurrence Is the Most Important Characteristic of Spot Sign.

Science.gov (United States)

Wang, Binli; Yan, Shenqiang; Xu, Mengjun; Zhang, Sheng; Liu, Keqin; Hu, Haitao; Selim, Magdy; Lou, Min

2016-05-01

Most previous studies have used single-phase computed tomographic angiography to detect the spot sign, a marker for hematoma expansion (HE) in spontaneous intracerebral hemorrhage. We investigated whether defining the spot sign based on timing on perfusion computed tomography (CTP) would improve its specificity for predicting HE. We prospectively enrolled supratentorial spontaneous intracerebral hemorrhage patients who underwent CTP within 6 hours of onset. Logistic regression was performed to assess the risk factors for HE and poor outcome. Predictive performance of individual CTP spot sign characteristics were examined with receiver operating characteristic analysis. Sixty-two men and 21 women with spontaneous intracerebral hemorrhage were included in this analysis. Spot sign was detected in 46% (38/83) of patients. Receiver operating characteristic analysis indicated that the timing of spot sign occurrence on CTP had the greatest area under receiver operating characteristic curve for HE (0.794; 95% confidence interval, 0.630-0.958; P=0.007); the cutoff time was 23.13 seconds. On multivariable analysis, the presence of early-occurring spot sign (ie, spot sign before 23.13 seconds) was an independent predictor not only of HE (odds ratio=28.835; 95% confidence interval, 6.960-119.458; Pspot sign maintained a higher specificity for HE compared with spot sign (91% versus 74%). Redefining the spot sign based on timing of contrast leakage on CTP to determine early-occurring spot sign improves the specificity for predicting HE and 3-month mortality. The use of early-occurring spot sign could improve the selection of ICH patients for potential hemostatic therapy. © 2016 American Heart Association, Inc.

[Rocky Mountain spotted fever in Brazil].

Science.gov (United States)

del Sá DelFiol, Fernando; Junqueira, Fábio Miranda; da Rocha, Maria Carolina Pereira; de Toledo, Maria Inês; Filho, Silvio Barberato

2010-06-01

Although the number of confirmed cases of spotted fever has been declining in Brazil since 2005, the mortality rate (20% to 30%) is still high in comparison to other countries. This high mortality rate is closely related to the difficulty in making the diagnosis and starting the correct treatment. Only two groups of antibiotics have proven clinical effectiveness against spotted fever: chloramphenicol and tetracyclines. Until recently, the use of tetracyclines was restricted to adults because of the associated bone and tooth changes in children. Recently, however, the American Academy of Pediatrics and various researchers have recommended the use of doxycycline in children. In more severe cases, chloramphenicol injections are often preferred in Brazil because of the lack of experience with injectable tetracycline. Since early diagnosis and the adequate drug treatment are key to a good prognosis, health care professionals must be better prepared to recognize and treat spotted fever.

Gas flow dependence for plasma-needle disinfection of S. mutans bacteria

International Nuclear Information System (INIS)

Goree, J; Liu Bin; Drake, David

2006-01-01

The role of gas flow and transport mechanisms are studied for a small low-power impinging jet of weakly-ionized helium at atmospheric pressure. This plasma needle produces a non-thermal glow discharge plasma that kills bacteria. A culture of Streptococcus mutans (S. mutans) was plated onto the surface of agar, and spots on this surface were then treated with plasma. Afterwards, the sample was incubated and then imaged. These images, which serve as a biological diagnostic for characterizing the plasma, show a distinctive spatial pattern for killing that depends on the gas flow rate. As the flow is increased, the killing pattern varies from a solid circle to a ring. Images of the glow reveal that the spatial distribution of energetic electrons corresponds to the observed killing pattern. This suggests that a bactericidal species is generated in the gas phase by energetic electrons less than a millimetre from the sample surface. Mixing of air into the helium plasma is required to generate the observed O and OH radicals in the flowing plasma. Hydrodynamic processes involved in this mixing are buoyancy, diffusion and turbulence

Gas flow dependence for plasma-needle disinfection of S. mutans bacteria

Energy Technology Data Exchange (ETDEWEB)

Goree, J [Department of Physics and Astronomy, University of Iowa, Iowa City, IA 52242 (United States); Liu Bin [Department of Physics and Astronomy, University of Iowa, Iowa City, IA 52242 (United States); Drake, David [Dows Institute for Dental Research, Dept. of Endodontics, College of Dentistry, University of Iowa, Iowa City, IA 52242 (United States)

2006-08-21

The role of gas flow and transport mechanisms are studied for a small low-power impinging jet of weakly-ionized helium at atmospheric pressure. This plasma needle produces a non-thermal glow discharge plasma that kills bacteria. A culture of Streptococcus mutans (S. mutans) was plated onto the surface of agar, and spots on this surface were then treated with plasma. Afterwards, the sample was incubated and then imaged. These images, which serve as a biological diagnostic for characterizing the plasma, show a distinctive spatial pattern for killing that depends on the gas flow rate. As the flow is increased, the killing pattern varies from a solid circle to a ring. Images of the glow reveal that the spatial distribution of energetic electrons corresponds to the observed killing pattern. This suggests that a bactericidal species is generated in the gas phase by energetic electrons less than a millimetre from the sample surface. Mixing of air into the helium plasma is required to generate the observed O and OH radicals in the flowing plasma. Hydrodynamic processes involved in this mixing are buoyancy, diffusion and turbulence.

High-energy 4ω probe laser for laser-plasma experiments at Nova

International Nuclear Information System (INIS)

Glenzer, S.H.; Weiland, T.L.; Bower, J.; MacKinnon, A.J.; MacGowan, B.J.

1999-01-01

For the characterization of inertial confinement fusion plasmas, we implemented a high-energy 4ω probe laser at the Nova laser facility. A total energy of >50 J at 4ω, a focal spot size of order 100 μm, and a pointing accuracy of 100 μm was demonstrated for target shots. This laser provides intensities of up to 3x10 14 Wcm -2 and therefore fulfills high-power requirements for laser-plasma interaction experiments. The 4ω probe laser is now routinely used for Thomson scattering. Successful experiments were performed in gas-filled hohlraums at electron densities of n e >2x10 21 cm -3 which represents the highest density plasma so far being diagnosed with Thomson scattering. copyright 1999 American Institute of Physics

Experimental study of population inversion in laser plasmas

International Nuclear Information System (INIS)

Bocher, J.L.; Busquet, M.; Combis, M.; Le Breton, J.P.; Louis-Jacquet, M.; Mexmain, J.M.; Naudy, M.

1986-06-01

Thin and thick composite targets of various material (Al, CH, Au) have been irradiated on both circular and linear focal spot with the laser Octal facility at wavelength 1.06 μm and 0.35 μm and laser irradiances (5.10 12 .W/cm 2 to 5.10 14 .W/cm 2 ). X-ray spectra, in the ranges 5-8 A and 15 - 300 A, recorded respectively by means of flat TIAP and grazing incidence spectrographs show an experimental evidence of population inversion in aluminium plasmas

First Beam Test of Nanometer Spot Size Monitor Using Laser Interferometry

CERN Document Server

Walz, D

2003-01-01

The nanometer spot size monitor based on the laser interferometry (Laser-Compton Spot Size Monitor) has been tested in FFTB beam line at SLAC. A low emittance beam of 46 GeV electrons, provided by the two-mile linear accelerator, was focused into nanometer spot in the FFTB line, and its transverse dimensions were precisely measured by the spot size monitor.

First Beam Test of Nanometer Spot Size Monitor Using Laser Interferometry

International Nuclear Information System (INIS)

Walz, Dieter R

2003-01-01

The nanometer spot size monitor based on the laser interferometry (Laser-Compton Spot Size Monitor) has been tested in FFTB beam line at SLAC. A low emittance beam of 46 GeV electrons, provided by the two-mile linear accelerator, was focused into nanometer spot in the FFTB line, and its transverse dimensions were precisely measured by the spot size monitor

Computed tomography angiography spot sign predicts intraprocedural aneurysm rupture in subarachnoid hemorrhage.

Science.gov (United States)

Burkhardt, Jan-Karl; Neidert, Marian Christoph; Stienen, Martin Nikolaus; Schöni, Daniel; Fung, Christian; Roethlisberger, Michel; Corniola, Marco Vincenzo; Bervini, David; Maduri, Rodolfo; Valsecchi, Daniele; Tok, Sina; Schatlo, Bawarjan; Bijlenga, Philippe; Schaller, Karl; Bozinov, Oliver; Regli, Luca

2017-07-01

To analyze whether the computed tomography angiography (CTA) spot sign predicts the intraprocedural rupture rate and outcome in patients with aneurysmal subarachnoid hemorrhage (aSAH). From a prospective nationwide multicenter registry database, 1023 patients with aneurysmal subarachnoid hemorrhage (aSAH) were analyzed retrospectively. Descriptive statistics and logistic regression analysis were used to compare spot sign-positive and -negative patients with aneurysmal intracerebral hemorrhage (aICH) for baseline characteristics, aneurysmal and ICH imaging characteristics, treatment and admission status as well as outcome at discharge and 1-year follow-up (1YFU) using the modified Rankin Scale (mRS). A total of 218 out of 1023 aSAH patients (21%) presented with aICH including 23/218 (11%) patients with spot sign. Baseline characteristics were comparable between spot sign-positive and -negative patients. There was a higher clip-to-coil ratio in patients with than without aICH (both spot sign positive and negative). Median aICH volume was significantly higher in the spot sign-positive group (50 ml, 13-223 ml) than in the spot sign-negative group (18 ml, 1-416; p spot sign-positive aICH thus were three times as likely as those with spot sign-negative aICH to show an intraoperative aneurysm rupture [odds ratio (OR) 3.04, 95% confidence interval (CI) 1.04-8.92, p = 0.046]. Spot sign-positive aICH patients showed a significantly worse mRS at discharge (p = 0.039) than patients with spot sign-negative aICH (median mRS 5 vs. 4). Logistic regression analysis showed that the spot sign was an aICH volume-dependent predictor for outcome. Both spot sign-positive and -negative aICH patients showed comparable rates of hospital death, death at 1YFU and mRS at 1YFU. In this multicenter data analysis, patients with spot sign-positive aICH showed higher aICH volumes and a higher rate of intraprocedural aneurysm rupture, but comparable long-term outcome to spot sign

Methodology and software to detect viral integration site hot-spots

Science.gov (United States)

2011-01-01

Background Modern gene therapy methods have limited control over where a therapeutic viral vector inserts into the host genome. Vector integration can activate local gene expression, which can cause cancer if the vector inserts near an oncogene. Viral integration hot-spots or 'common insertion sites' (CIS) are scrutinized to evaluate and predict patient safety. CIS are typically defined by a minimum density of insertions (such as 2-4 within a 30-100 kb region), which unfortunately depends on the total number of observed VIS. This is problematic for comparing hot-spot distributions across data sets and patients, where the VIS numbers may vary. Results We develop two new methods for defining hot-spots that are relatively independent of data set size. Both methods operate on distributions of VIS across consecutive 1 Mb 'bins' of the genome. The first method 'z-threshold' tallies the number of VIS per bin, converts these counts to z-scores, and applies a threshold to define high density bins. The second method 'BCP' applies a Bayesian change-point model to the z-scores to define hot-spots. The novel hot-spot methods are compared with a conventional CIS method using simulated data sets and data sets from five published human studies, including the X-linked ALD (adrenoleukodystrophy), CGD (chronic granulomatous disease) and SCID-X1 (X-linked severe combined immunodeficiency) trials. The BCP analysis of the human X-linked ALD data for two patients separately (774 and 1627 VIS) and combined (2401 VIS) resulted in 5-6 hot-spots covering 0.17-0.251% of the genome and containing 5.56-7.74% of the total VIS. In comparison, the CIS analysis resulted in 12-110 hot-spots covering 0.018-0.246% of the genome and containing 5.81-22.7% of the VIS, corresponding to a greater number of hot-spots as the data set size increased. Our hot-spot methods enable one to evaluate the extent of VIS clustering, and formally compare data sets in terms of hot-spot overlap. Finally, we show that the

Does the G-spot exist? A review of the current literature.

Science.gov (United States)

Puppo, Vincenzo; Gruenwald, Ilan

2012-12-01

In 1950, Gräfenberg described a distinct erotogenic zone on the anterior wall of the vagina, which was referred to as the Gräfenberg spot (G-spot) by Addiego, Whipple (a nurse) et al. in 1981. As a result, the G-spot has become a central topic of popular speculation and a basis of a huge business surrounding it. In our opinion, these sexologists have made a hotchpotch of Gräfenberg's thoughts and ideas that were set forth and expounded in his 1950 article: the intraurethral glands are not the corpus spongiosum of the female urethra, and Gräfenberg did not report an orgasm of the intraurethral glands. G-spot amplification is a cosmetic surgery procedure for temporarily increasing the size and sensitivity of the G-spot in which a dermal filler or a collagen-like material is injected into the bladder-vaginal septum. All published scientific data point to the fact that the G-spot does not exist, and the supposed G-spot should not be identified with Gräfenberg's name. Moreover, G-spot amplification is not medically indicated and is an unnecessary and inefficacious medical procedure.

Time-dependent simulation of plasma and electrodes in high-intensity discharge lamps with different electrode shapes

CERN Document Server

Flesch, P

2003-01-01

The subject of this paper is the modelling of d.c. and a.c. high-intensity Hg-discharge lamps with differently shaped electrodes. Different arc attachments on the electrodes are studied and insight for the development of new electrodes is gained. The model includes the entire discharge plasma (plasma column, hot plasma spots in front of electrodes, near-electrode non-LTE-plasma) as well as anode and cathode. No subdivision of the discharge space into different regions is necessary (like space charge layer, ionization zone, plasma column). This is achieved by using a differential equation for a non-LTE electrical conductivity which is applicable for local thermal equilibrium (LTE-)regions as well as for non-LTE plasma regions close to the electrodes in a high pressure plasma. Modelling results for a 0.6 MPa mercury discharge considering six different electrode shapes (anode and cathode) are presented and compared with experimental results. The electrodes have different diameters and different electrode tips, s...

A measurement concept for hot-spot BRDFs from space

Energy Technology Data Exchange (ETDEWEB)

Gerstl, S.A.W.

1996-09-01

Several concepts for canopy hot-spot measurements from space have been investigated. The most promising involves active illumination and bistatic detection that would allow hot-spot angular distribution (BRDF) measurements from space in a search-light mode. The concept includes a pointable illumination source, such as a laser operating at an atmospheric window wavelength, coupled with a number of high spatial-resolution detectors that are clustered around the illumination source in space, receiving photons nearly coaxial with the reto-reflection direction. Microwave control and command among the satellite cluster would allow orienting the direction of the laser beam as well as the focusing detectors simultaneously so that the coupled system can function like a search light with almost unlimited pointing capabilities. The concept is called the Hot-Spot Search-Light (HSSL) satellite. A nominal satellite altitude of 600 km will allow hot-spot BRDF measurements out to about 18 degrees phase angle. The distributed are taking radiometric measurements of the intensity wings of the hot-spot angular distribution without the need for complex imaging detectors. The system can be operated at night for increased signal-to-noise ratio. This way the hot-spot angular signatures can be quantified and parameterized in sufficient detail to extract the biophysical information content of plant architectures.

A measurement concept for hot-spot BRDFs from space

Science.gov (United States)

Gerstl, S.A.W.

1996-01-01

Several concepts for canopy hot-spot measurements from space have been investigated. The most promising involves active illumination and bistatic detection that would allow hot-spot angular distribution (BRDF) measurements from space in a search-light mode. The concept includes a pointable illumination source, such as a laser operating at an atmospheric window wavelength, coupled with a number of high spatial-resolution detectors that are clustered around the illumination source in space, receiving photons nearly coaxial with the reto-reflection direction. Microwave control and command among the satellite cluster would allow orienting the direction of the laser beam as well as the focusing detectors simultaneously so that the coupled system can function like a search light with almost unlimited pointing capabilities. The concept is called the Hot-Spot Search-Light (HSSL) satellite. A nominal satellite altitude of 600 km will allow hot-spot BRDF measurements out to about 18 degrees phase angle. The distributed are taking radiometric measurements of the intensity wings of the hot-spot angular distribution without the need for complex imaging detectors. The system can be operated at night for increased signal-to-noise ratio. This way the hot-spot angular signatures can be quantified and parameterized in sufficient detail to extract the biophysical information content of plant architectures.

Insights from ecological niche modeling on the taxonomic distinction and niche differentiation between the black-spotted and red-spotted tokay geckoes (Gekko gecko).

Science.gov (United States)

Zhang, Yueyun; Chen, Chongtao; Li, Li; Zhao, Chengjian; Chen, Weicai; Huang, Yong

2014-09-01

The black-spotted tokay and the red-spotted tokay are morphologically distinct and have largely allopatric distributions. The black-spotted tokay is characterized by a small body size and dark skin with sundry spots, while the red-spotted tokay has a relatively large body size and red spots. Based on morphological, karyotypic, genetic, and distribution differences, recent studies suggested their species status; however, their classifications remain controversial, and additional data such as ecological niches are necessary to establish firm hypotheses regarding their taxonomic status. We reconstructed their ecological niches models using climatic and geographic data. We then performed niche similarity tests (niche identity and background tests) and point-based analyses to explore whether ecological differentiation has occurred, and whether such differences are sufficient to explain the maintenance of their separate segments of environmental ranges. We found that both niche models of the black- and the red-spotted tokay had a good fit and a robust performance, as indicated by the high area under the curve (AUC) values ("black" = 0.982, SD = ± 0.002, "red" = 0.966 ± 0.02). Significant ecological differentiation across the entire geographic range was found, indicating that the involvement of ecological differentiation is important for species differentiation. Divergence along the environmental axes is highly associated with climatic conditions, with isothermality being important for the "black" form, while temperature seasonality, precipitation of warmest quarter, and annual temperature range together being important for the "red" form. These factors are likely important factors in niche differentiation between the two forms, which result in morphological replacement. Overall, beside morphological and genetic differentiation information, our results contribute to additional insights into taxonomic distinction and niche differentiation between the black- and the red-spotted

Dry Blood Spots a Reliable Method for Measurement of Hepatitis B Viral Load in Resource-Limited Settings.

Directory of Open Access Journals (Sweden)

Kathrine Stene-Johansen

Full Text Available Hepatitis B virus (HBV quantification is essential in the management of chronic hepatitis B, both to determine treatment eligibility and in the monitoring of treatment effect. This test, however, is rarely available in resource-limited settings due to high costs and stringent requirements for shipment and storage of plasma. Dried Blood Spots (DBS can be a convenient alternative to plasma, but its use for HBV monitoring has not been investigated under real-life conditions in Africa.The performance of DBS in HBV quantification was investigated using a modified commercial test (Abbott RealTime HBV assay. Paired DBS and plasma samples were collected from an HBV positive cohort in Addis Ababa, Ethiopia. DBS were stored at ambient temperature for 4-39 days before shipment to the laboratory.Twenty-six paired samples were selected covering the total range of quantification, from 2.14 log IU/ml to >7 log IU/ml. HBV was detected in 21 of 21 (100% DBS from patients with a corresponding plasma viral load above 2.70 log IU/ml. The mean difference between plasma and DBS was 0.59 log IU/ml, and the correlation was strong (R2 = 0.92. In stability studies there was no significant change in DBS viral load after storage at room temperature for up to 12 weeks.This study suggests that DBS can be a feasible and reliable alternative to plasma for quantification of HBV in resource-limited settings. DBS can expand access to antiviral treatment for patients in low- and middle-income countries.

White-centred retinal haemorrhages (Roth spots).

Science.gov (United States)

Ling, R; James, B

1998-10-01

Roth spots (white-centred retinal haemorrhages) were classically described as septic emboli lodged in the retina of patients with subacute bacterial endocarditis. Indeed many have considered Roth spots pathognomonic for this condition. More recent histological evidence suggests, however, that they are not foci of bacterial abscess. Instead, they are nonspecific and may be found in many other diseases. A review of the histology and the pathogenesis of these white-centred haemorrhages will be provided, along with the work-up of the differential diagnosis.

Matching sub-fs electron bunches for laser-driven plasma acceleration at SINBAD

Energy Technology Data Exchange (ETDEWEB)

Zhu, J., E-mail: jun.zhu@desy.de [Deutsches Elektronen-Synchrotron, DESY, Hamburg (Germany); Universität Hamburg, Hamburg (Germany); Assmann, R.W.; Dorda, U.; Marchetti, B. [Deutsches Elektronen-Synchrotron, DESY, Hamburg (Germany)

2016-09-01

We present theoretical and numerical studies of matching sub-femtosecond space-charge-dominated electron bunch into the Laser-plasma Wake Field Accelerator (LWFA) foreseen at the SINBAD facility. The longitudinal space-charge (SC) effect induced growths of the energy spread and longitudinal phase-space chirp are major issues in the matching section, which will result in bunch elongation, emittance growth and spot size dilution. In addition, the transverse SC effect would lead to a mismatch of the beam optics if it were not compensated for. Start-to-end simulations and preliminary optimizations were carried out in order to understand the achievable beam parameters at the entrance of the plasma accelerator.

Long-term Spot-Coverage Variations of 13 BY Dra G-K Dwarfs

Science.gov (United States)

Alekseev, I. Yu.; Kozhevnikova, A. V.

2018-06-01

The results of spot-coverage modeling for 13 active G-K dwarf stars based on many-year photometric observations are presented. The results of UBV RI observations of eight stars performed at the Crimean Astrophysical Observatory were used together with data from the literature in this analysis. The spot-coverage parameters for 13 selected BY Dra active red dwarfs have been redetermined to improve the zonal spot-coverage model for the stellar photospheres, which currently allows for the presence of two active longitudes. Time variations of the spot-activity characteristics of these systems were analyzed with the aim of searching for possible cyclic variations. All the stars, with the exception of OU Gem and BE Cet, show fairly strong correlations between variations in the spot latitudes and spot areas, with absolute values of the correlation coefficients, R(, S), ranging from 0.38 to 0.92. For five stars, an anti-correlation between the mean latitude and area of the spots was found ( R(, S) from-0.24 to-0.73). This behavior may reflect the drift of spots toward the equator in the course of their development. Eight stars feature positive correlations, i.e. the spots drift towards the pole as their areas increase. Nine stars demonstrate activity cycles, which are reflected in photometric variations as well as variations of the spot areas and mean latitudes. The periods of the latitude drift of the spots are found for five stars; the magnitudes of the spot-latitude drift rates are lower than the corresponding value for sunspots by a factor of 1.5-3.

PREDICTING RELEVANT EMPTY SPOTS IN SOCIAL INTERACTION

Institute of Scientific and Technical Information of China (English)

Yoshiharu MAENO; Yukio OHSAWA

2008-01-01

An empty spot refers to an empty hard-to-fill space which can be found in the records of the social interaction, and is the clue to the persons in the underlying social network who do not appear in the records. This contribution addresses a problem to predict relevant empty spots in social interaction. Homogeneous and inhomogeneous networks are studied as a model underlying the social interaction. A heuristic predictor function method is presented as a new method to address the problem. Simulation experiment is demonstrated over a homogeneous network. A test data set in the form of market baskets is generated from the simulated communication. Precision to predict the empty spots is calculated to demonstrate the performance of the presented method.

How much extra spot gas is there?

International Nuclear Information System (INIS)

Bros, Th.

2007-01-01

With the increase of European gas demand and the sharp decrease of local supply, security of supply is becoming an ever greater issue. However, liberalization tilts the traditional equilibrium based on long term 'take or pay' contracts between big suppliers and national distribution companies. Today, buying gas on the spot market is becoming more and more important to balance supply portfolio with a fast moving market share. But the way gas spot markets are operating is not well documented. It is very difficult to assess its impact on the European security of supply. Therefore, the aim of this article is to evaluate the amount of 'spot' liquefied natural gas (LNG) that could be found in case of a major supply disruption in pipe gas delivered to Europe

Thermophysical properties of multi-shock compressed dense argon.

Science.gov (United States)

Chen, Q F; Zheng, J; Gu, Y J; Chen, Y L; Cai, L C; Shen, Z J

2014-02-21

In contrast to the single shock compression state that can be obtained directly via experimental measurements, the multi-shock compression states, however, have to be calculated with the aid of theoretical models. In order to determine experimentally the multiple shock states, a diagnostic approach with the Doppler pins system (DPS) and the pyrometer was used to probe multiple shocks in dense argon plasmas. Plasma was generated by a shock reverberation technique. The shock was produced using the flyer plate impact accelerated up to ∼6.1 km/s by a two-stage light gas gun and introduced into the plenum argon gas sample, which was pre-compressed from the environmental pressure to about 20 MPa. The time-resolved optical radiation histories were determined using a multi-wavelength channel optical transience radiance pyrometer. Simultaneously, the particle velocity profiles of the LiF window was measured with multi-DPS. The states of multi-shock compression argon plasma were determined from the measured shock velocities combining the particle velocity profiles. We performed the experiments on dense argon plasmas to determine the principal Hugonoit up to 21 GPa, the re-shock pressure up to 73 GPa, and the maximum measure pressure of the fourth shock up to 158 GPa. The results are used to validate the existing self-consistent variational theory model in the partial ionization region and create new theoretical models.

Spot på interaktive teknologier

DEFF Research Database (Denmark)

Brooks, Anthony Lewis

2014-01-01

Spot på interaktive teknologier Af Anthony Lewis Brooks, PhD Associate Professor, Aalborg University & Director SensoramaLab Den verdensomspændende paraplyorganisation for it-foreninger IFIP har netop afholdt sin årlige ”International Conference on Entertainment Computing”. Se her, hvad tre af top...... fra hele verden for at sætte fokus på, hvordan de nyeste teknologier inden for digital underholdning, kan bruges i forskellige sammenhænge. Bag begivenheden står IFIP, som DANSK IT er repræsenteret i. I år var der blandt andet spot på wearables og andre interaktive teknologier. Leila Alem fra den...

78 FR 9330 - Revision of Regulations Defining Bona Fide Cotton Spot Markets

Science.gov (United States)

2013-02-08

... Cotton Spot Markets AGENCY: Agricultural Marketing Service, USDA. ACTION: Proposed rule. SUMMARY: The... bona fide cotton spot markets in order to assure consistency with the revised Cotton Research and Promotion Act. Updated bona fide spot market definitions will allow for published spot quotes to consider...

Management of white spots: resin infiltration technique and microabrasion

Directory of Open Access Journals (Sweden)

Jeong-Hye Son

2011-01-01

Full Text Available This case report compared the effectiveness of resin infiltration technique (Icon, DMG with microabrasion (Opalustre, Ultradent Products, Inc. in management of white spot lesions. It demonstrates that although neither microabrasion nor resin infiltration technique can remove white spot lesions completely, resin infiltration technique seems to be more effective than microabrasion. Therefore resin infiltration technique can be chosen preferentially for management of white spot lesions and caution should be taken for case selection.

Allowable propagation of short pulse laser beam in a plasma channel and electromagnetic solitary waves

International Nuclear Information System (INIS)

Zhang, Shan; Hong, Xue-Ren; Wang, Hong-Yu; Xie, Bai-Song

2011-01-01

Nonparaxial and nonlinear propagation of a short intense laser beam in a parabolic plasma channel is analyzed by means of the variational method and nonlinear dynamics. The beam propagation properties are classified by five kinds of behaviors. In particularly, the electromagnetic solitary wave for finite pulse laser is found beside the other four propagation cases including beam periodically oscillating with defocussing and focusing amplitude, constant spot size, beam catastrophic focusing. It is also found that the laser pulse can be allowed to propagate in the plasma channel only when a certain relation for laser parameters and plasma channel parameters is satisfied. For the solitary wave, it may provide an effective way to obtain ultra-short laser pulse.

Design of a cost-effective laser spot tracker

Science.gov (United States)

Artan, Göktuǧ Gencehan; Sari, Hüseyin

2017-05-01

One of the most important aspects of guided systems is detection. The most convenient detection in the sense of precision can be achieved with a laser spot tracker. This study deals with a military grade, high performance and cost-effective laser spot tracker for a guided system. The aim is to develop a high field of view system that will detect a laser spot from a distance of 3 kilometers in which the target is designated from 3 kilometers with a laser. The study basically consists of the system design, modeling, producing and the conducting performance tests of the whole system.

Experimental study of plasma energy transfer and material erosion under ELM-like heat loads

Energy Technology Data Exchange (ETDEWEB)

Garkusha, I.E., E-mail: garkusha@ipp.kharkov.u [Institute of Plasma Physics of the NSC KIPT, Akademicheskaya 1, 61108 Kharkov (Ukraine); Makhlaj, V.A.; Chebotarev, V.V. [Institute of Plasma Physics of the NSC KIPT, Akademicheskaya 1, 61108 Kharkov (Ukraine); Landman, I. [Forschungszentrum Karlsruhe, IHM, 76021 Karlsruhe (Germany); Tereshin, V.I.; Aksenov, N.N.; Bandura, A.N. [Institute of Plasma Physics of the NSC KIPT, Akademicheskaya 1, 61108 Kharkov (Ukraine)

2009-06-15

Main features of plasma-surface interaction and energy transfer to tokamak plasma facing components are studied at different heat loads in ELM simulation experiments with the plasma gun QSPA Kh-50. Repetitive plasma exposures of tungsten, graphite and different combined W-C targets were performed at the pulse duration of 0.25 ms and the heat loads varied in the range 0.2-2.5 MJ/m{sup 2}. The onset of vapor shield in front of the surface was investigated. The evaporation is immediately followed by a saturation of surface heat load if further increasing the impact energy. The presence of graphite essentially decreases the heat flux to the nearby tungsten surface, which is due to the carbon vapor shield. Droplet splashing at the tungsten surface and formation of hot spots on the graphite surface are discussed.

Experimental study of plasma energy transfer and material erosion under ELM-like heat loads

International Nuclear Information System (INIS)

Garkusha, I.E.; Makhlaj, V.A.; Chebotarev, V.V.; Landman, I.; Tereshin, V.I.; Aksenov, N.N.; Bandura, A.N.

2009-01-01

Main features of plasma-surface interaction and energy transfer to tokamak plasma facing components are studied at different heat loads in ELM simulation experiments with the plasma gun QSPA Kh-50. Repetitive plasma exposures of tungsten, graphite and different combined W-C targets were performed at the pulse duration of 0.25 ms and the heat loads varied in the range 0.2-2.5 MJ/m 2 . The onset of vapor shield in front of the surface was investigated. The evaporation is immediately followed by a saturation of surface heat load if further increasing the impact energy. The presence of graphite essentially decreases the heat flux to the nearby tungsten surface, which is due to the carbon vapor shield. Droplet splashing at the tungsten surface and formation of hot spots on the graphite surface are discussed.

Electricity spot price dynamics: Beyond financial models

International Nuclear Information System (INIS)

Guthrie, Graeme; Videbeck, Steen

2007-01-01

We reveal properties of electricity spot prices that cannot be captured by the statistical models, commonly used to model financial asset prices, that are increasingly used to model electricity prices. Using more than eight years of half-hourly spot price data from the New Zealand Electricity Market, we find that the half-hourly trading periods fall naturally into five groups corresponding to the overnight off-peak, the morning peak, daytime off-peak, evening peak, and evening off-peak. The prices in different trading periods within each group are highly correlated with each other, yet the correlations between prices in different groups are lower. Models, adopted from the modeling of security prices, that are currently applied to electricity spot prices are incapable of capturing this behavior. We use a periodic autoregression to model prices instead, showing that shocks in the peak periods are larger and less persistent than those in off-peak periods, and that they often reappear in the following peak period. In contrast, shocks in the off-peak periods are smaller, more persistent, and die out (perhaps temporarily) during the peak periods. Current approaches to modeling spot prices cannot capture this behavior either. (author)

Spot market activity remains weak as prices continue to fall

International Nuclear Information System (INIS)

Anon.

1996-01-01

A summary of financial data for the uranium spot market in November 1996 is provided. Price ranges for the restricted and unrestricted markets, conversion, and separative work are listed, and total market volume and new contracts are noted. Transactions made are briefly described. Deals made and pending in the spot concentrates, medium and long-term, conversion, and markets are listed for U.S. and non-U.S. buyers. Spot market activity increased in November with just over 1.0 million lbs of U3O8 equivalent being transacted compared to October's total of 530,000 lbs of U3O8 equivalent. The restricted uranium spot market price range slipped from $15.50-$15.70/lb U3O8 last month to $14.85/lb - $15.25/lb U3O8 this month. The unrestricted uranium spot market price range also slipped to $14.85/lb - $15.00/lb this month from $15.00/lb - $15.45/lb in October. Spot prices for conversion and separative work units remained at their October levels