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Sample records for acquire polarization resolved

  1. Time Resolved Spectroscopy of Eclipsing Polars

    NASA Astrophysics Data System (ADS)

    Barrett, Paul

    2005-09-01

    No changes have been made since the last annual progress report was submitted in conjunction with a unilateral NCX. Dr. Barrett was affected by an STScI Reduction in Force (RIF). He is now employed by the Johns Hopkins University and plans to continue his research there. No expenses have been charged to this grant, however the FUSE data for the eclipsing polar V1432 Aql has been received and processed using CALFWSE v3.0.6. The resulting summed spectrum has been used for a preliminary analysis of the interstellar absorption towards V1432 Aql. We find a hydrogen column density of less than 1.5e21 cm^-2. We have used this result in the paper "X-Ray Emission and Optical Polarization of V1432 Aquilae: An Asynchronous Polar" to fix the hydrogen column density in the soft (<0.5 keV) X-ray band when analyzing the XMM-Newton spectra of this polar. This has enabled us to find an accurate temperature for the blackbody component of 88+/-2 eV, which is significantly higher than that of other polars (20 - 40 eV). We hope to complete our analysis of the phase-resolved emission line spectra of V1432 Aql and to prepare the results for publication in a refereed journal. We hope to begin work on this star within the next few months.

  2. Time Resolved Spectroscopy of Eclipsing Polars

    NASA Technical Reports Server (NTRS)

    Barrett, Paul

    2005-01-01

    No changes have been made since the last annual progress report was submitted in conjunction with a unilateral NCX. Dr. Barrett was affected by an STScI Reduction in Force (RIF). He is now employed by the Johns Hopkins University and plans to continue his research there. No expenses have been charged to this grant, however the FUSE data for the eclipsing polar V1432 Aql has been received and processed using CALFWSE v3.0.6. The resulting summed spectrum has been used for a preliminary analysis of the interstellar absorption towards V1432 Aql. We find a hydrogen column density of less than 1.5e21 cm^-2. We have used this result in the paper "X-Ray Emission and Optical Polarization of V1432 Aquilae: An Asynchronous Polar" to fix the hydrogen column density in the soft (<0.5 keV) X-ray band when analyzing the XMM-Newton spectra of this polar. This has enabled us to find an accurate temperature for the blackbody component of 88+/-2 eV, which is significantly higher than that of other polars (20 - 40 eV). We hope to complete our analysis of the phase-resolved emission line spectra of V1432 Aql and to prepare the results for publication in a refereed journal. We hope to begin work on this star within the next few months.

  3. Polarization resolved angular optical scattering of aerosol particles

    NASA Astrophysics Data System (ADS)

    Redding, B.; Pan, Y.; Wang, C.; Videen, G.; Cao, Hui

    2014-05-01

    Real-time detection and identification of bio-aerosol particles are crucial for the protection against chemical and biological agents. The strong elastic light scattering properties of airborne particles provides a natural means for rapid, non-invasive aerosol characterization. Recent theoretical predictions suggested that variations in the polarization dependent angular scattering cross section could provide an efficient means of classifying different airborne particles. In particular, the polarization dependent scattering cross section of aggregate particles is expected to depend on the shape of the primary particles. In order to experimentally validate this prediction, we built a high throughput, sampling system, capable of measuring the polarization resolved angular scattering cross section of individual aerosol particles flowing through an interrogating volume with a single shot of laser pulse. We calibrated the system by comparing the polarization dependent scattering cross section of individual polystyrene spheres with that predicted by Mie theory. We then used the system to study different particles types: Polystyrene aggregates composed 500 nm spheres and Bacillus subtilis (BG, Anthrax simulant) spores composed of elongated 500 nm × 1000 nm cylinder-line particles. We found that the polarization resolved scattering cross section depends on the shape of the constituent elements of the aggregates. This work indicates that the polarization resolved scattering cross section could be used for rapid discrimination between different bio-aerosol particles.

  4. Acquired umbilical hernias in four captive polar bears (Ursus maritimus).

    PubMed

    Velguth, Karen E; Rochat, Mark C; Langan, Jennifer N; Backues, Kay

    2009-12-01

    Umbilical hernias are a common occurrence in domestic animals and humans but have not been well documented in polar bears. Surgical reduction and herniorrhaphies were performed to correct acquired hernias in the region of the umbilicus in four adult captive polar bears (Ursus maritimus) housed in North American zoos. Two of the four bears were clinically unaffected by their hernias prior to surgery. One bear showed signs of severe discomfort following acute enlargement of the hernia. In another bear, re-herniation led to acute abdominal pain due to gastric entrapment and strangulation. The hernias in three bears were surgically repaired by debridement of the hernia ring and direct apposition of the abdominal wall, while the large defect in the most severely affected bear was closed using polypropylene mesh to prevent excessive tension. The cases in this series demonstrate that while small hernias may remain clinically inconsequential for long periods of time, enlargement or recurrence of the defect can lead to incarceration and acute abdominal crisis. Umbilical herniation has not been reported in free-ranging polar bears, and it is suspected that factors such as body condition, limited exercise, or enclosure design potentially contribute to the development of umbilical hernias in captive polar bears.

  5. Depth-resolved measurements with elliptically polarized reflectance spectroscopy

    PubMed Central

    Bailey, Maria J.; Sokolov, Konstantin

    2016-01-01

    The ability of elliptical polarized reflectance spectroscopy (EPRS) to detect spectroscopic alterations in tissue mimicking phantoms and in biological tissue in situ is demonstrated. It is shown that there is a linear relationship between light penetration depth and ellipticity. This dependence is used to demonstrate the feasibility of a depth-resolved spectroscopic imaging using EPRS. The advantages and drawbacks of EPRS in evaluation of biological tissue are analyzed and discussed. PMID:27446712

  6. Imaging dental sections with polarization-resolved SHG and time-resolved autofluorescence

    NASA Astrophysics Data System (ADS)

    Chen, Jun Huang; Lin, Po-Yen; Hsu, Stephen C. Y.; Kao, Fu-Jen

    2009-02-01

    In this study, we are using two-photon (2-p) excited autofluorescence and second harmonic (SH) as imaging modalities to investigate dental sections that contains the enamel and the dentin. The use of near-infrared wavelengths for multiphoton excitation greatly facilitates the observation of these sections due to the hard tissue's larger index of refraction and highly scattering nature. Clear imaging can be achieved without feature altering preparation procedures of the samples. Specifically, we perform polarization resolving on SH and lifetime analysis on autofluorescence. Polarization resolved SH reflects the preferred orientation of collagen while very different autofluorescence lifetimes are observed from the dentin and the enamel. The origin of 2-p autofluorescence and SH signals are attributed to hydroxyapatite crystals and collagen fibrils, respectively. Hydroxyapatite is found to be present throughout the sections while collagen fibrils exist only in the dentin and dentinoenamel junctions.

  7. Polarization resolved near-IR imaging of sound and carious dental enamel

    NASA Astrophysics Data System (ADS)

    Darling, Cynthia L.; Chan, Kenneth H.; Fried, Daniel

    2011-03-01

    A thorough understanding of how polarized near-IR light is reflected from and transmitted through sound and carious dental hard tissues is important for the development of optical imaging devices. New optical imaging tools employing non-ionizing radiation are needed for the detection and assessment of dental caries. In this investigation, an automated system was developed to collect images for the full 16-element Mueller Matrix. The polarized light was controlled by linear polarizers and liquid crystal retarders and the 36 images were acquired as the polarized near-IR light is reflected from the occlusal surface or transmitted through thin sections of extracted human whole teeth. Previous near-IR imaging studies suggest that polarization imaging can be exploited to obtain higher contrast images of early dental caries due to the rapid depolarization of incident polarized light by the highly scattering areas of decay. In this study, the reflectance from tooth occlusal surfaces with demineralization and transmitted light through tooth thin sections with caries lesions were investigated. Major differences in the Mueller matrix elements were observed in both sound and demineralized enamel. This study suggests that polarization resolved optical imaging can be exploited to obtain higher contrast images of dental decay.

  8. Nonselective and polarization effects in time-resolved optogalvanic spectroscopy

    NASA Astrophysics Data System (ADS)

    Zhechev, D.; Steflekova, V.

    2016-02-01

    Three interfering effects in optogalvanic (OG) spectroscopy are identified in a hollow cathode discharge (HCD) - OG detector. The laser beam is found to generate two nonselective processes, namely photoelectron emission (PE) from the cathode surface with a sub-breakdown bias applied, and nonresonant space ionization. The convolution of these galvanic contributions was determined experimentally as an instrumental function and a deconvolution procedure to determine the actual OG signal was developed. Specific plasma conductance is detected dependent on the polarization of the laser beam irradiating. Linearly/circularly polarized light beam is found to induce OG signals differ in amplitude (and their shape parameters in the time-resolved OG signals (TROGS)). The phenomena coherence and specific conductance are found to be in causal relationship. The additional conductance due to coherent states of atoms manifests itself as an intrinsic instrumental property of OG detector.

  9. POC in the process of acquiring polarization characteristics

    NASA Astrophysics Data System (ADS)

    Zhou, Xiaojun; Cao, Ercong; Gu, Guohua; Qian, Weixian; Yang, Wei; Zhang, Haiyue

    2016-09-01

    Considering the change of optical information on material surface, this paper proposes a useful notion called pixel-level optical constants (POC). Through Fresnel equations, traditional optical constants (refractive index n and extinction coefficient k ) can reflect photoelectric characteristics on material surface. Combining with Mueller calculus in polarization optics, POC can describe the distrbution of photoelectric characteristics on material surface. POC is mainly calculated by the decomposition of Mueller matrix which includes Fresnel amplitude, ratio of two orthogonal reflection coefficient component P and variation of phase difference between incident light and reflected light Δ . With the regularity of polarized light and the statistics of Mueller matrices, optical characteristics can be detailed to each pixel in POC, which will independently show the distribution of polarization characteristics on material surface. And it can also be approximately averaged to obtain traditional optical constants. So POC is significant to optical researches on material surface.

  10. Spectrally- and polarization-resolved hyper-Rayleigh scattering measurements with polarization-insensitive detection

    NASA Astrophysics Data System (ADS)

    Němec, P.; Pásztor, F.; Brajer, M.; Němec, I.

    2017-04-01

    Determination of the molecular first hyperpolarizability by hyper-Rayleigh scattering (HRS) is usually significantly complicated by a presence of the multiphoton excited fluorescence which has to be separated from HRS to obtain a meaningful values of the hyperpolarizability. We show, by performing a spectrally-resolved measurement, that the intensity and spectral shape of the fluorescence can depend strongly on the fundamental laser wavelength. Consequently, a properly selected excitation wavelength can significantly simplify the process of separation of HRS from the detected signal. We tested the developed experimental setup with a polarization-insensitive detection by measuring HRS generated in water and in aqueous solutions of 2-aminopyrimidine (AMP) and its monocation (HAMP). The effective hyperpolarizability of AMP and HAMP was measured experimentally and compared with that obtained by quantum chemical calculations. The polarization-resolved HRS measurement was performed for AMP and the experimentally obtained depolarization ratio agrees well with that predicted theoretically, which confirms that routine density functional theory computations of static hyperpolarizability tensor components can be considered as a sufficient approach suitable for non-interacting molecules dissolved in water.

  11. Optical diagnosis and characterization of dental caries with polarization-resolved hyperspectral stimulated Raman scattering microscopy

    PubMed Central

    Wang, Zi; Zheng, Wei; Hsu, Stephen Chin-Ying; Huang, Zhiwei

    2016-01-01

    We report the utility of a rapid polarization-resolved hyperspectral stimulated Raman scattering (SRS) imaging technique developed for optical diagnosis and characterization of dental caries in the tooth. Hyperspectral SRS images (512 × 512 pixels) of the tooth covering both the fingerprint (800-1800 cm−1) and high-wavenumber (2800-3600 cm−1) regions can be acquired within 15 minutes, which is at least 103 faster in imaging speed than confocal Raman mapping. Hyperspectral SRS imaging uncovers the biochemical distributions and variations across the carious enamel in the tooth. SRS imaging shows that compared to the sound enamel, the mineral content in the body of lesion decreases by 55%; while increasing up to 110% in the surface zone, indicating the formation of a hyper-mineralized layer due to the remineralization process. Further polarized SRS imaging shows that the depolarization ratios of hydroxyapatite crystals (ν1-PO43- of SRS at 959 cm−1) of the tooth in the sound enamel, translucent zone, body of lesion and the surface zone are 0.035 ± 0.01, 0.052 ± 0.02, 0.314 ± 0.1, 0.038 ± 0.02, respectively, providing a new diagnostic criterion for discriminating carious lesions from sound enamel in the teeth. This work demonstrates for the first time that the polarization-resolved hyperspectral SRS imaging technique can be used for quantitatively determining tooth mineralization levels and discriminating carious lesions from sound enamel in a rapid fashion, proving its promising potential of early detection and diagnosis of dental caries without labeling. PMID:27446654

  12. A LACK OF RESOLVED NEAR-INFRARED POLARIZATION ACROSS THE FACE OF M51

    SciTech Connect

    Pavel, Michael D.; Clemens, Dan P. E-mail: clemens@bu.edu

    2012-12-20

    The galaxy M51 was observed using the Mimir instrument on the Perkins Telescope to constrain the resolved H-band (1.6 {mu}m) polarization across the galaxy. These observations place an upper limit of P{sub H} < 0.05% on the H-band polarization across the face of M51, at 0.6 arcsec pixel sampling. Even with smoothing to coarser angular resolutions, to reduce polarization uncertainty, the H-band polarization remains undetected. The polarization upper limit at H band, when combined with previous resolved optical polarimetry, rules out a Serkowski-like polarization dependence on wavelength. Other polarization mechanisms cannot account for the observed polarization ratio (P{sub H}/P{sub VRI} {approx}< 0.05) across the face of M51.

  13. Wavelength resolved polarized elastic scatter measurements from micron-sized single particles

    NASA Astrophysics Data System (ADS)

    Sivaprakasam, Vasanthi; Czege, Jozsef; Eversole, Jay D.

    2013-05-01

    The goal of this project is to investigate correlations of polarimetric angular scattering patterns from individual aerosol particles with the particles' physical structure and composition. Such signature patterns may be able to provide particle classification capability, such as, for example, discrimination between man-made and naturally occurring aerosols. If successful, this effort could improve current detection methods for biological warfare (BW) agent aerosols. So far, we have demonstrated an experimental arrangement to measure polarization-state resolved, multi-angle, scattering intensities from single aerosol particles on-the-fly. Our novel approach is a radical departure from conventional polarimetric measurement methods, and a key factor is the use of a multiple-order retarder to prepare different polarization states, depending on the wavelength of the incident light. This novel experimental technique uses a supercontinuum light source, an array of optical fibers, an imaging spectrometer and an EMCCD camera to simultaneously acquire wavelength and angle dependent particle light scattering data as a two-dimensional snapshot. Mueller matrix elements were initially measured from individual particles held in an optical trap (at 405 nm). Since particles can be stably trapped for long periods (hours), we were able to change the optical configuration to acquire multiple Mueller matrix element measurements on a single particle. We have computationally modeled these measurements at specific angles, and the comparison with experimental measurements shows good agreement. Similar measurements have also been made on slowly falling particles, and our current efforts are focused on improving experimental technique sufficiently to make such measurements on flowing particles.

  14. Improved quantification of collagen anisotropy with polarization-resolved second harmonic generation microscopy.

    PubMed

    Hristu, Radu; Stanciu, Stefan G; Tranca, Denis E; Stanciu, George A

    2016-10-24

    Imaging tissue samples by polarization-resolved second harmonic generation microscopy provides both qualitative and quantitative insights into collagen organization in a label-free manner. Polarization-resolved second harmonic generation microscopy goes beyond simple intensity-based imaging by adding the laser beam polarization component and applying different quantitative metrics such as the anisotropy factor. It thus provides valuable information on collagen arrangement not available with intensity measurements alone. Current established approaches are limited to calculating the anisotropy factor for only a particular laser beam polarization and no general guidelines on how to select the best laser beam polarization have yet been defined. Here, we introduce a novel methodology for selecting the optimal laser beam polarization for characterizing tissues using the anisotropy in the purpose of identifying cancer signatures. We show that the anisotropy factor exhibits a similar laser beam polarization dependence to the second harmonic intensity and we combine it with the collagen orientation index computed by Fast Fourier Transform analysis of the recorded images to establish a framework for choosing the laser beam polarization that is optimal for an accurate interpretation of polarization-resolved second harmonic generation microscopy images and anisotropy maps, and hence a better differentiation between healthy and dysplastic areas. SHG image of skin tissue (a) and a selected area of interest for which we compute the SHG intensity (b) and anisotropy factor (c) dependence on the laser beam polarization and also the FFT spectrum (d) to evaluate the collagen orientation index.

  15. Polar plot representation of time-resolved fluorescence.

    PubMed

    Eichorst, John Paul; Wen Teng, Kai; Clegg, Robert M

    2014-01-01

    Measuring changes in a molecule's fluorescence emission is a common technique to study complex biological systems such as cells and tissues. Although the steady-state fluorescence intensity is frequently used, measuring the average amount of time that a molecule spends in the excited state (the fluorescence lifetime) reveals more detailed information about its local environment. The lifetime is measured in the time domain by detecting directly the decay of fluorescence following excitation by short pulse of light. The lifetime can also be measured in the frequency domain by recording the phase and amplitude of oscillation in the emitted fluorescence of the sample in response to repetitively modulated excitation light. In either the time or frequency domain, the analysis of data to extract lifetimes can be computationally intensive. For example, a variety of iterative fitting algorithms already exist to determine lifetimes from samples that contain multiple fluorescing species. However, recently a method of analysis referred to as the polar plot (or phasor plot) is a graphical tool that projects the time-dependent features of the sample's fluorescence in either the time or frequency domain into the Cartesian plane to characterize the sample's lifetime. The coordinate transformations of the polar plot require only the raw data, and hence, there are no uncertainties from extensive corrections or time-consuming fitting in this analysis. In this chapter, the history and mathematical background of the polar plot will be presented along with examples that highlight how it can be used in both cuvette-based and imaging applications.

  16. RESOLVE for Lunar Polar Ice/Volatile Characterization Mission

    NASA Technical Reports Server (NTRS)

    Sanders, G. B.; Larson, W. E.; Quinn, J. W.; Colaprete, A.; Picard, M.; Boucher, D.

    2011-01-01

    Ever since data from the neutron spectrometer instrument on the Lunar Prospector mission indicated the possibility of significant concentrations of hydrogen at the lunar poles, speculation on the form and concentration of the hydrogen has been debated. The recent impact of the Lunar Crater Observation and Sensing Satellite (LCROSS) along with thermal, topographic, neutron spectrometry, and radar frequency data obtained from the Lunar Reconnaissance Orbiter (LRO) have provided more information suggesting significant amounts of water/ice and other volatiles may be available in the top 1 to 2 meters of regolith at the lunar poles. The next step in understanding what resources are available at the lunar poles is to perform a mission to obtain ground truth. data. To meet this need, the US National Aeronautics and Space Administration (NASA) along with the Canadian Space Agency (CSA) have been working on a prototype payload known as the Regolith & Environment Science and Oxygen & Lunar Volatile Extraction experiment, or RESOLVE.

  17. Automated system to acquire fluorescence, polarization and anisotropy maps within liquid flows

    PubMed Central

    Gonçalves, Cristiane C.; Pepe, Iuri; Lima, Angelo M. V.; Musse, Ana Paula S.

    2002-01-01

    Maps of polarization and anisotropy can be helpful for flow analysis systems (FIA, CFA, etc.) with reactions dependent on the intermolecular alignment as well as for dispersion control. Maps can be acquired manually, but when a scan over a sample area is required, the acquisition becomes tiresome and has low precision. The paper describes an automatic flexible system for high-precision sample positioning with closed loop self control, remote data acquisition and storage controlled by a BASIC program. The system was developed to acquire maps up to 850 mm2 of the sample (liquid flows, solids, interfaces, etc.), with up to 100 μm2 precision. To evaluate the equipment, performance is presented as the scan of a thin liquid film of monoethylene glycol (MEG) flowing on borosilicate. Tests were performed with and without surfactantes at submicellar concentrations: two concentrations of sodium dodecyl sulphate (SDS) and one of polyethylene oxide (PEO). For pure MEG, the intermolecular alignment initially increased, then decreased. When SDS was added, both polarization and anisotropy only increased progressively with the flow. This might be explained by the surfactant decrease of interfacial interaction. When PEO was added, both polarization and anisotropy decreased pronouncedly over the entire map, which might be due to macromolecular aggregates within the bulk generating misaligned molecular domains. The system presented as sample positioning repeatability of 0.1% and a high polarization reproducibility (error margin < 6 in 1000). PMID:18924741

  18. Prospecting for Polar Volatiles: Results from the Resolve Field

    NASA Technical Reports Server (NTRS)

    Elphic, Richard C.; Colarprete, Anthony; Deans, Matthew C.; Heldman, Jennifer; Sanders, Gerald B.; Larson, William E.

    2013-01-01

    Both the Moon and Mercury evidently host ice and other volatile compounds in cold traps at the planets poles. Determining the form, spatial distribution, and abundance of these volatiles at the lunar poles can help us understand how and when they were delivered and emplaced. This bears directly on the delivery of water and prebiotic compounds to the inner planets over the solar system s history, and also informs plans for utilizing the volatiles as resources for sustained human exploration as well as the commercial development of space. Temperature models and orbital data suggest near-surface volatile concentrations may exist at polar locations not strictly in permanent shadow. Remote operation of a robotic lunar rover mission for the 7-10 days of available sunlight would permit key questions to be answered. But such a short, quick-tempo mission has unique challenges and requires a new concept of operations. Both science and rover operations decisionmaking must be done in real time, requiring immediate situational awareness, data analysis, and decision support tools.

  19. Hierarchical model of fibrillar collagen distribution for polarization-resolved SHG microscopy

    NASA Astrophysics Data System (ADS)

    Tuer, Adam E.; Akens, Margarete K.; Krouglov, Serguei; Sandkuijl, Daaf; Wilson, Brian C.; Whyne, Cari M.; Barzda, Virginijus

    2013-02-01

    A hierarchical model of the organization of fibrillar collagen is developed and its implications on polarization-resolved second harmonic generation (SHG) microscopy are investigated. A "ground-up" approach is employed to develop the theory for understanding of the origin of SHG from fibrillar collagen. The effects of fibril ultrastructure and fibril macroscopic organization on the second-order polarization properties of fibrillar collagen are presented in conjunction with recent ab initio results performed on a collagen triple-helix model (-GLY-PRO-HYP-)n. Various tissues containing fibrillar collagen are quantified using a polarization-resolved SHG technique, termed polarization-in, polarization-out (PIPO) and interpreted in light of the aforementioned theory. The method involves varying the incident laser polarization, while monitoring the SHG intensity through an analyzer. From the SHG polarization data the orientation of the fibers, in biological tissue, can be deduced. Unique PIPO signatures are observed for different rat tissues and interpreted in terms of the collagen composition, fibril ultrastructure, and macroscopic organization. Similarities and discrepancies in the second-order polarization properties of different collagen types and ultrastructures will be presented. PIPO SHG microscopy shows promise in its ability to quantify the organization of collagen in various tissues. The ability to characterize the structure of collagen in various tissue microenvironments will aid in the study of numerous collagen related biological process, including tissue diseases, wound repair, and tumor development and progression.

  20. Motionless polarization-resolved second harmonic generation imaging of corneal collagen

    NASA Astrophysics Data System (ADS)

    Breunig, Hans G.; Batista, Ana; Uchugonova, Aisada; König, Karsten

    2015-03-01

    Polarization-resolved second harmonic generation microscopy was used to investigate the collagenous structures of cornea samples in vitro in forward and backward direction. Although structural features appear different in both directions, following an approach by Latour et al. the collagen domain orientation is determined in forward as well as in backward direction, the latter being the only accessible direction for in vivo imaging. The experimental setup enables fast and completely motionless rotation of the polarization direction of 100 fs pulses by a polarization rotation based on a liquid crystal retarder.

  1. Early dental caries detection using a fibre-optic coupled polarization-resolved Raman spectroscopic system.

    PubMed

    Ko, Alex C-T; Hewko, Mark; Sowa, Michael G; Dong, Cecilia C S; Cleghorn, Blaine; Choo-Smith, Lin-P'ing

    2008-04-28

    A new fibre-optic coupled polarization-resolved Raman spectroscopic system was developed for simultaneous collection of orthogonally polarized Raman spectra in a single measurement. An application of detecting incipient dental caries based on changes observed in Raman polarization anisotropy was also demonstrated using the developed fibre-optic Raman spectroscopic system. The predicted reduction of polarization anisotropy in the Raman spectra of caries lesions was observed and the results were consistent with those reported previously with Raman microspectroscopy. The capability of simultaneous collection of parallel- and cross-polarized Raman spectra of tooth enamel in a single measurement and the improved laser excitation delivery through fibre-optics demonstrated in this new design illustrates its future clinical potential.

  2. Early dental caries detection using a fibre-optic coupled polarization-resolved Raman spectroscopic system

    PubMed Central

    Ko, Alex C.-T.; Hewko, Mark; Sowa, Michael G.; Dong, Cecilia C.S.; Cleghorn, Blaine; Choo-Smith, Lin-P’ing

    2008-01-01

    A new fibre-optic coupled polarization-resolved Raman spectroscopic system was developed for simultaneous collection of orthogonally polarized Raman spectra in a single measurement. An application of detecting incipient dental caries based on changes observed in Raman polarization anisotropy was also demonstrated using the developed fibre-optic Raman spectroscopic system. The predicted reduction of polarization anisotropy in the Raman spectra of caries lesions was observed and the results were consistent with those reported previously with Raman microspectroscopy. The capability of simultaneous collection of parallel-and cross-polarized Raman spectra of tooth enamel in a single measurement and the improved laser excitation delivery through fibre-optics demonstrated in this new design illustrates its future clinical potential. PMID:18545331

  3. In vivo multiphoton imaging of the cornea: polarization-resolved second harmonic generation from stromal collagen

    NASA Astrophysics Data System (ADS)

    Latour, G.; Gusachenko, I.; Kowalczuk, L.; Lamarre, I.; Schanne-Klein, M.-C.

    2012-03-01

    Multiphoton microscopy provides specific and contrasted images of unstained collagenous tissues such as tendons or corneas. Polarization-resolved second harmonic generation (SHG) measurements have been implemented in a laserscanning multiphoton microscope. Distortion of the polarimetric response due to birefringence and diattenuation during propagation of the laser excitation has been shown in rat-tail tendons. A model has been developed to account for these effects and correct polarization-resolved SHG images in thick tissues. This new modality is then used in unstained human corneas to access two quantitative parameters: the fibrils orientation within the collagen lamellae and the ratio of the main second-order nonlinear tensorial components. Orientation maps obtained from polarization resolution of the trans-detected SHG images are in good agreement with the striated features observed in the raw images. Most importantly, polarization analysis of the epi-detected SHG images also enables to map the fibrils orientation within the collagen lamellae while epi-detected SHG images of corneal stroma are spatially homogenous and do not enable direct visualization of the fibrils orientation. Depth profiles of the polarimetric SHG response are also measured and compared to models accounting for orientation changes of the collagen lamellae within the focal volume. Finally, in vivo polarization-resolved SHG is performed in rat corneas and structural organization of corneal stroma is determined using epi-detected signals.

  4. Crop discrimination on ENVISAT ASAR images acquired in alternating polarization mode

    NASA Astrophysics Data System (ADS)

    Stankiewicz, Krystyna A.

    2005-10-01

    The objective of this study is to find an efficient method of crop classification based solely on satellite microwave data. Microwave data can sometimes be the only non-contaminated satellite data available for a selected area, where frequent cloudiness makes optical data useless. Hence, this approach has to be studied at least as an alternative method for application when other data are missing. Although ASAR is not a fully polarimetric instrument, a selection of dual polarization modes and a selection of incidence angles are available when using ASAR alternating polarization product (APP). Larger incidence angle and cross-polarized data are better for crop discrimination, while lower incidence angle and co-polarized data contain more information on soil moisture. In the years 2003 and 2004 a sequence of ASAR IS2, IS4 and IS6 images acquired during a growth season was analyzed. Supervised classification of ASAR APP was performed with ground truth data collected for 700 plots covered by homogeneous crops. For growth seasons of 2003 and 2004 various combination of images were tested in order to find the best set of data providing the highest accuracy of crop classification.

  5. Spectroscopic approaches to resolving ambiguities of hyper-polarized NMR signals from different reaction cascades.

    PubMed

    Jensen, Pernille Rose; Meier, Sebastian

    2016-02-07

    The influx of exogenous substrates into cellular reaction cascades on the seconds time scale is directly observable by NMR spectroscopy when using nuclear spin polarization enhancement. Conventional NMR assignment spectra for the identification of reaction intermediates are not applicable in these experiments due to the non-equilibrium nature of the nuclear spin polarization enhancement. We show that ambiguities in the intracellular identification of transient reaction intermediates can be resolved by experimental schemes using site-specific isotope labelling, optimised referencing and response to external perturbations.

  6. Numerical simulation of polarization-resolved second-harmonic microscopy in birefringent media

    NASA Astrophysics Data System (ADS)

    Gusachenko, Ivan; Schanne-Klein, Marie-Claire

    2013-11-01

    Polarization-resolved second-harmonic microscopy has recently emerged as a valuable technique for in situ imaging of collagen structure in tissues. Nevertheless, collagen-rich tissues such as tendon, ligament, skin dermis, bone, cornea, or artery exhibit a heterogeneous and anisotropic architecture that results in complex optical properties. While experimental evidence of polarization distortions has been reported in various tissues, the physics of second-harmonic imaging within such tissues is not fully understood yet. In this work, we performed numerical simulations of polarization-resolved second-harmonic generation in a strongly focused regime within a birefringent tissue. We show that vectorial components due to strong focusing have a rather small effect on the measurement of the second-harmonic tensorial response, while birefringence and optical dispersion may affect these measurements dramatically. We show indeed that a difference in the focal field distribution for ordinary and extraordinary waves results in different phase-matching conditions, which strongly affects the relative efficacy of second-harmonic generation for different polarizations. These results are of great interest for extracting reliable quantitative parameters from second-harmonic images.

  7. Spectrally resolved fluorescence lifetime imaging of Nile red for measurements of intracellular polarity

    NASA Astrophysics Data System (ADS)

    Levitt, James A.; Chung, Pei-Hua; Suhling, Klaus

    2015-09-01

    Spectrally resolved confocal microscopy and fluorescence lifetime imaging have been used to measure the polarity of lipid-rich regions in living HeLa cells stained with Nile red. The emission peak from the solvatochromic dye in lipid droplets is at a shorter wavelength than other, more polar, stained internal membranes, and this is indicative of a low polarity environment. We estimate that the dielectric constant, ɛ, is around 5 in lipid droplets and 25<ɛ<40 in other lipid-rich regions. Our spectrally resolved fluorescence lifetime imaging microscopy (FLIM) data show that intracellular Nile red exhibits complex, multiexponential fluorescence decays due to emission from a short lifetime locally excited state and a longer lifetime intramolecular charge transfer state. We measure an increase in the average fluorescence lifetime of the dye with increasing emission wavelength, as shown using phasor plots of the FLIM data. We also show using these phasor plots that the shortest lifetime decay components arise from lipid droplets. Thus, fluorescence lifetime is a viable contrast parameter for distinguishing lipid droplets from other stained lipid-rich regions. Finally, we discuss the FLIM of Nile red as a method for simultaneously mapping both polarity and relative viscosity based on fluorescence lifetime measurements.

  8. An imaging spectro-polarimeter for measuring hemispherical spectrally resolved down-welling sky polarization

    NASA Astrophysics Data System (ADS)

    Chenault, David B.; Pezzaniti, J. L.; Roche, Michael; Hyatt, Brian

    2016-05-01

    A full sky imaging spectro-polarimeter has been developed that measures spectrally resolved (~2.5 nm resolution) radiance and polarization (𝑠0, 𝑠1, 𝑠2 Stokes Elements) of natural sky down-welling over approximately 2π sr between 400nm and 1000nm. The sensor is based on a scanning push broom hyperspectral imager configured with a continuously rotating polarizer (sequential measurement in time polarimeter). Sensor control and processing software (based on Polaris Sensor Technologies Grave' camera control software) has a straight-forward and intuitive user interface that provides real-time updated sky down-welling spectral radiance/polarization maps and statistical analysis tools.

  9. Time-resolved fluorescence polarization spectroscopy of visible and near infrared dyes in picosecond dynamics

    NASA Astrophysics Data System (ADS)

    Pu, Yang; Alfano, Robert R.

    2015-03-01

    Near-infrared (NIR) dyes absorb and emit light within the range from 700 to 900 nm have several benefits in biological studies for one- and/or two-photon excitation for deeper penetration of tissues. These molecules undergo vibrational and rotational motion in the relaxation of the excited electronic states, Due to the less than ideal anisotropy behavior of NIR dyes stemming from the fluorophores elongated structures and short fluorescence lifetime in picosecond range, no significant efforts have been made to recognize the theory of these dyes in time-resolved polarization dynamics. In this study, the depolarization of the fluorescence due to emission from rotational deactivation in solution will be measured with the excitation of a linearly polarized femtosecond laser pulse and a streak camera. The theory, experiment and application of the ultrafast fluorescence polarization dynamics and anisotropy are illustrated with examples of two of the most important medical based dyes. One is NIR dye, namely Indocyanine Green (ICG) and is compared with Fluorescein which is in visible range with much longer lifetime. A set of first-order linear differential equations was developed to model fluorescence polarization dynamics of NIR dye in picosecond range. Using this model, the important parameters of ultrafast polarization spectroscopy were identified: risetime, initial time, fluorescence lifetime, and rotation times.

  10. Polarization-resolved SHG microscopy of rat-tail tendon with controlled mechanical strain

    NASA Astrophysics Data System (ADS)

    Gusachenko, I.; Goulam Houssen, Y.; Tran, V.; Allain, J.-M.; Schanne-Klein, M.-C.

    2013-06-01

    We combined polarization-resolved SHG microscopy with mechanical assays in rat-tail-tendon and measured collagen remodeling upon controlled stretching. This approach aimed to analyze the relationship between macroscopic response and sub-micrometer scale organization of collagen fibrils. We observed a straightening of the crimps followed by a sliding of the fibrils with increasing stretching of the tendon fascicles. Polarization resolution of the SHG images provided complementary information about the orientation dispersion of collagen fibrils within the focal volume and enabled monitoring of collagen remodeling at the sub-micrometer scale. Our approach can be readily generalized to other tissues and should bring new valuable information about biomechanics of microstructured tissues.

  11. Orientation-resolved domain mapping in tetragonal SrTiO3 using polarized Raman spectroscopy

    NASA Astrophysics Data System (ADS)

    Gray, Dodd J.; Merz, Tyler A.; Hikita, Yasuyuki; Hwang, Harold Y.; Mabuchi, Hideo

    2016-12-01

    We present microscopically resolved, polarized spectroscopy of Raman scattering collected from tetragonal SrTiO3. The anisotropic response of first-order Raman peaks within a single tetragonal domain has been measured. From these data, we assign symmetries to the phonons seen in the first-order Raman spectrum which is normally complicated by uncontrolled domain structure. Using a translation stage, we map the local domain orientation of a 3 -μ m3 crystal volume near the laser focus and compare it to wide-field polarized images. This technique can be performed with readily available instruments and is relevant to the study of a wide range of related materials, interfaces, and devices.

  12. Polar Dunes Resolved by the Mars Orbiter Laser Altimeter Gridded Topography and Pulse Widths

    NASA Technical Reports Server (NTRS)

    Neumann, Gregory A.

    2003-01-01

    The Mars Orbiter Laser Altimeter (MOLA) polar data have been refined to the extent that many features poorly imaged by Viking Orbiters are now resolved in densely gridded altimetry. Individual linear polar dunes with spacings of 0.5 km or more can be seen as well as sparsely distributed and partially mantled dunes. The refined altimetry will enable measurements of the extent and possibly volume of the north polar ergs. MOLA pulse widths have been recalibrated using inflight data, and a robust algorithm applied to solve for the surface optical impulse response. It shows the surface root-mean-square (RMS) roughness at the 75-m-diameter MOLA footprint scale, together with a geological map. While the roughness is of vital interest for landing site safety studies, a variety of geomorphological studies may also be performed. Pulse widths corrected for regional slope clearly delineate the extent of the polar dunes. The MOLA PEDR profile data have now been re-released in their entirety (Version L). The final Mission Experiment Gridded Data Records (MEGDR's) are now provided at up to 128 pixels per degree globally. Densities as high as 512 pixels per degree are available in a polar stereographic projection. A large computational effort has been expended in improving the accuracy of the MOLA altimetry themselves, both in improved orbital modeling and in after-the-fact adjustment of tracks to improve their registration at crossovers. The current release adopts the IAU2000 rotation model and cartographic frame recommended by the Mars Cartography Working Group. Adoption of the current standard will allow registration of images and profiles globally with an uncertainty of less than 100 m. The MOLA detector is still operational and is currently collecting radiometric data at 1064 nm. Seasonal images of the reflectivity of the polar caps can be generated with a resolution of about 300 m per pixel.

  13. Spin-orbit-induced photoelectron spin polarization in angle-resolved photoemission from both atomic and condensed matter targets.

    PubMed

    Heinzmann, Ulrich; Dil, J Hugo

    2012-05-02

    The existence of highly spin polarized photoelectrons emitted from non-magnetic solids as well as from unpolarized atoms and molecules has been found to be very common in many studies over the past 40 years. This so-called Fano effect is based upon the influence of the spin-orbit interaction in the photoionization or the photoemission process. In a non-angle-resolved photoemission experiment, circularly polarized radiation has to be used to create spin polarized photoelectrons, while in angle-resolved photoemission even unpolarized or linearly polarized radiation is sufficient to get a high spin polarization. In past years the Rashba effect has become very important in the angle-resolved photoemission of solid surfaces, also with an observed high photoelectron spin polarization. It is the purpose of the present topical review to cross-compare the spin polarization experimentally found in angle-resolved photoelectron emission spectroscopy of condensed matter with that of free atoms, to compare it with the Rashba effect and topological insulators to describe the influence and the importance of the spin-orbit interaction and to show and disentangle the matrix element and phase shift effects therein.The relationship between the energy dispersion of these phase shifts and the emission delay of photoelectron emission in attosecond-resolved photoemission is also discussed. Furthermore the influence of chiral structures of the photo-effect target on the spin polarization, the interferences of different spin components in coherent superpositions in photoemission and a cross-comparison of spin polarization in photoemission from non-magnetic solids with XMCD on magnetic materials are presented; these are all based upon the influence of the spin-orbit interaction in angle-resolved photoemission.

  14. Polarization-resolved second-harmonic generation imaging for liver fibrosis assessment without labeling

    NASA Astrophysics Data System (ADS)

    Lin, Jian; Pan, Shiying; Zheng, Wei; Huang, Zhiwei

    2013-10-01

    We apply the polarization-resolved second-harmonic generation (PR-SHG) microscopy to investigate the changes of collagen typings (type I vs type III) and collagen fibril orientations of liver tissue in bile-duct-ligation (BDL) rat models. The PR-SHG results show that the second-order susceptibility tensor ratios (χ31/χ15 and χ33/χ15) of collagen fibers increase with liver fibrotic progression after BDL surgery, reflecting an increase of the type III collagen component with the severity of liver fibrosis; and the square root of the collagen type III to type I ratio linearly correlates (R2 = 0.98) with histopathological scores. Furthermore, the collagen fibril orientations become more random with liver fibrosis transformation as compared to normal liver tissue. This work demonstrates that PR-SHG microscopy has the potential for label-free diagnosis and characterization of liver fibrosis based on quantitative analysis of collagen typings and fibril orientations.

  15. Real-time inversion of polarization gate frequency-resolved optical gating spectrograms.

    PubMed

    Kane, Daniel J; Weston, Jeremy; Chu, Kai-Chien J

    2003-02-20

    Frequency-resolved optical gating (FROG) is a technique used to measure the intensity and phase of ultrashort laser pulses through the optical construction of a spectrogram of the pulse. To obtain quantitative information about the pulse from its spectrogram, an iterative two-dimensional phase retrieval algorithm must be used. Current algorithms are quite robust but retrieval of all the pulse information can be slow. Previous real-time FROG trace inversion work focused on second-harmonic-generation FROG, which has an ambiguity in the direction of time, and required digital signal processors (DSPs). We develop a simplified real-time FROG device based on a single-shot geometry that no longer requires DSPs. We use it and apply the principal component generalized projections algorithm to invert polarization gate FROG traces at rates as high as 20 Hz.

  16. Resolving the biophysics of axon transmembrane polarization in a single closed-form description

    NASA Astrophysics Data System (ADS)

    Melendy, Robert F.

    2015-12-01

    When a depolarizing event occurs across a cell membrane there is a remarkable change in its electrical properties. A complete depolarization event produces a considerably rapid increase in voltage that propagates longitudinally along the axon and is accompanied by changes in axial conductance. A dynamically changing magnetic field is associated with the passage of the action potential down the axon. Over 75 years of research has gone into the quantification of this phenomenon. To date, no unified model exist that resolves transmembrane polarization in a closed-form description. Here, a simple but formative description of propagated signaling phenomena in the membrane of an axon is presented in closed-form. The focus is on using both biophysics and mathematical methods for elucidating the fundamental mechanisms governing transmembrane polarization. The results presented demonstrate how to resolve electromagnetic and thermodynamic factors that govern transmembrane potential. Computational results are supported by well-established quantitative descriptions of propagated signaling phenomena in the membrane of an axon. The findings demonstrate how intracellular conductance, the thermodynamics of magnetization, and current modulation function together in generating an action potential in a unified closed-form description. The work presented in this paper provides compelling evidence that three basic factors contribute to the propagated signaling in the membrane of an axon. It is anticipated this work will compel those in biophysics, physical biology, and in the computational neurosciences to probe deeper into the classical and quantum features of membrane magnetization and signaling. It is hoped that subsequent investigations of this sort will be advanced by the computational features of this model without having to resort to numerical methods of analysis.

  17. Resolving the biophysics of axon transmembrane polarization in a single closed-form description

    SciTech Connect

    Melendy, Robert F.

    2015-12-28

    When a depolarizing event occurs across a cell membrane there is a remarkable change in its electrical properties. A complete depolarization event produces a considerably rapid increase in voltage that propagates longitudinally along the axon and is accompanied by changes in axial conductance. A dynamically changing magnetic field is associated with the passage of the action potential down the axon. Over 75 years of research has gone into the quantification of this phenomenon. To date, no unified model exist that resolves transmembrane polarization in a closed-form description. Here, a simple but formative description of propagated signaling phenomena in the membrane of an axon is presented in closed-form. The focus is on using both biophysics and mathematical methods for elucidating the fundamental mechanisms governing transmembrane polarization. The results presented demonstrate how to resolve electromagnetic and thermodynamic factors that govern transmembrane potential. Computational results are supported by well-established quantitative descriptions of propagated signaling phenomena in the membrane of an axon. The findings demonstrate how intracellular conductance, the thermodynamics of magnetization, and current modulation function together in generating an action potential in a unified closed-form description. The work presented in this paper provides compelling evidence that three basic factors contribute to the propagated signaling in the membrane of an axon. It is anticipated this work will compel those in biophysics, physical biology, and in the computational neurosciences to probe deeper into the classical and quantum features of membrane magnetization and signaling. It is hoped that subsequent investigations of this sort will be advanced by the computational features of this model without having to resort to numerical methods of analysis.

  18. Study of Microheterogeneity in Acetonitrile-Water Binary Mixtures by using Polarity-Resolved Solvation Dynamics.

    PubMed

    Koley, Somnath; Ghosh, Subhadip

    2015-11-16

    The solvation dynamics of three coumarin dyes with widely varying polarities were studied in acetonitrile-water (ACN-H2O) mixtures across the entire composition range. At low ACN concentrations [ACN mole fractions (X(ACN))≤0.1], the solvation dynamics are fast (<40 ps), indicating a nearly homogeneous environment. This fast region is followed by a sudden retardation of the average solvation time (230-1120 ps) at higher ACN concentrations (X(ACN)≈0.2), thus indicating the onset of nonideality within the mixture that continues until X(ACN)≈0.8. This nonideality regime (X(ACN)≈0.2-0.8) comprises of multiple dye-dependent anomalous regions. At very high ACN concentrations (X(ACN)≈0.8-1), the ACN-H2O mixtures regain homogeneity, with faster solvation times. The source of the inherent nonideality of the ACN-H2O mixtures is a subject of debate. However, a careful examination of the widths of time-resolved emission spectra shows that the origin of the slow dynamics may be due to the diffusion of polar solvent molecules into the first solvation shell of the excited coumarin dipole.

  19. Moisture-insensitive optical fingerprint scanner based on polarization resolved in-finger scattered light.

    PubMed

    Back, Seon-Woo; Lee, Yong-Geon; Lee, Sang-Shin; Son, Geun-Sik

    2016-08-22

    A moisture-insensitive optical fingerprint scanner (FPS) that is based on polarization resolved in-finger light is proposed and realized. Incident visible light, which is selectively fed to a fingerprint sample via a polarization beam splitter (PBS), is deemed to be partially scattered backward by tissues associated with the skin of the finger. The backscattered light is mostly index-guided in the ridge comprising the fingerprint, which has a higher refractive index, and is drastically dispersed in the valley, which is typically filled with water or air and so has a lower index. However, when light reflects directly off the surface of the finger skin, it fundamentally prevents the scanned image from being determined. The proposed FPS produces bright and dark intensity patterns that are alternately created on the surface of the PBS and correspond to the ridges and valleys, respectively. Thus, this method can especially distinguish between a fake synthetic fingerprint and a genuine fingerprint due to its use of in-finger scattered light. The scanner has been rigorously designed by carrying out ray-optic simulations depending on the wavelength, with tissue-induced scattering taken into account. The device was constructed by incorporating a wire-grid type PBS in conjunction with visible LED sources, including blue, green and red. The scanner adopting a blue LED, which exhibits the strongest light scattering, resulted in the best fingerprint image, enabling enhanced fidelity under the wet and dry situations. Finally, a fake synthetic fingerprint could be successfully discriminated.

  20. Nodal gap detection through polar angle-resolved density of states measurements in uniaxial superconductors

    NASA Astrophysics Data System (ADS)

    Tsutsumi, Yasumasa; Nomoto, Takuya; Ikeda, Hiroaki; Machida, Kazushige

    2016-12-01

    We propose a spectroscopic method to identify the nodal gap structure in unconventional superconductors. This method is best suited for locating the horizontal line node and for pinpointing the isolated point nodes by measuring polar angle (θ ) resolved zero-energy density of states N (θ ) . This is measured by specific heat or thermal conductivity at low temperatures under a magnetic field. We examine a variety of uniaxially symmetric nodal structures, including point and/or line nodes with linear and quadratic dispersions, by solving the Eilenberger equation in vortex states. It is found that (a) the maxima of N (θ ) continuously shift from the antinodal to the nodal direction (θn) as a field increases accompanying the oscillation pattern reversal at low and high fields. Furthermore, (b) local minima emerge next to θn on both sides, except for the case of the linear point node. These features are robust and detectable experimentally. Experimental results of N (θ ) performed on several superconductors, UPd2Al3,URu2Si2,CuxBi2Se3 , and UPt3, are examined and commented on in light of the present theory.

  1. Development of a polarization-modulation spectroscopy system for the temporally resolved measurement of linear polarization in plasma emission

    NASA Astrophysics Data System (ADS)

    Yasui, Kenji; Shikama, Taiichi; Higashi, Takanori; Hasuo, Masahiro

    2016-10-01

    A system to measure linear polarization in the HeI 21P-31D emission line (667.8 nm) was developed for application to plasma polarization spectroscopy. To verify the system performance, the normalized Stokes parameters were evaluated. A measurement error of less than 1% with a time resolution of 1 ms was achieved for monochromatic light in the state of complete linear polarization.

  2. Polarization-resolved hyperspectral stimulated Raman scattering microscopy for label-free biomolecular imaging of the tooth

    NASA Astrophysics Data System (ADS)

    Wang, Zi; Zheng, Wei; Hsu, Chin-Ying Stephen; Huang, Zhiwei

    2016-01-01

    We report the development and implementation of a rapid polarization-resolved hyperspectral stimulated Raman scattering (SRS) microscopy technique for label-free biomolecular imaging of the tooth. The hyperspectral SRS imaging technique developed covers both fingerprint (800-1800 cm-1) and high-wavenumber (2800-3600 cm-1) regions for tooth Raman imaging without fluorescence background interference with an imaging speed of <0.3 s per frame of 512 × 512 pixels (˜1 μs per pixel), that is, >106 faster than confocal Raman imaging. Significant differences of hyperspectral SRS spectra among different tooth locations (e.g., dentin, enamel, and dentin-enamel junction) are observed, revealing the biochemical distribution differences across the tooth. Further polarization-resolved SRS imaging shows different polarization dependences related to the molecular orientation differences of various tooth locations. This work demonstrates the potential of polarization-resolved hyperspectral SRS imaging technique developed in rapidly characterizing biochemical structures and compositions as well as biomolecule organizations/orientations of the tooth without labeling.

  3. Generation of an axially super-resolved quasi-spherical focal spot using an amplitude-modulated radially polarized beam.

    PubMed

    Lin, Han; Jia, Baohua; Gu, Min

    2011-07-01

    An axially super-resolved quasi-spherical focal spot can be generated by focusing an amplitude-modulated radially polarized beam through a high numerical aperture objective. A method based on the unique depolarization properties of a circular focus is proposed to design the amplitude modulation. The generated focal spot shows a ratio of x:y:z=1:1:1.48 for the normalized FWHM in three dimensions, compared to that of x:y:z=1:0.74:1.72 under linear polarization (in the x direction) illumination. Moreover, the focusable light efficiency of the designed amplitude-modulated beam is 65%, which is more than 3 times higher than the optimized case under linear polarization and thus make the amplitude-modulated radial polarization beam more suitable for a wide range of applications.

  4. Highly polarized emission in spin resolved photoelectron spectroscopy of alpha-Fe(001)/GaAs(001)

    SciTech Connect

    Tobin, James; Yu, Sung Woo; Morton, Simon; Waddill, George; Thompson, Jamie; Neal, James; Spangenberg, Matthais; Shen, T.H.

    2009-05-19

    Highly spin-polarized sources of electrons, Integrated into device design, remain of great interest to the spintronic and magneto-electronic device community Here, the growth of Fe upon GaAs(001) has been studied with photoelectron spectroscopy (PES), including Spin Resolved PES. Despite evidence of atomic level disorder such as intermixing, an over-layer with the spectroscopic signature of alpha-Fe(001), with a bcc real space ordering, Is obtained The results will be discussed in light of the possibility of using such films as a spin-polarized source in device applications.

  5. Circularly polarized near-field optical mapping of spin-resolved quantum Hall chiral edge states.

    PubMed

    Mamyouda, Syuhei; Ito, Hironori; Shibata, Yusuke; Kashiwaya, Satoshi; Yamaguchi, Masumi; Akazaki, Tatsushi; Tamura, Hiroyuki; Ootuka, Youiti; Nomura, Shintaro

    2015-04-08

    We have successfully developed a circularly polarized near-field scanning optical microscope (NSOM) that enables us to irradiate circularly polarized light with spatial resolution below the diffraction limit. As a demonstration, we perform real-space mapping of the quantum Hall chiral edge states near the edge of a Hall-bar structure by injecting spin polarized electrons optically at low temperature. The obtained real-space mappings show that spin-polarized electrons are injected optically to the two-dimensional electron layer. Our general method to locally inject spins using a circularly polarized NSOM should be broadly applicable to characterize a variety of nanomaterials and nanostructures.

  6. Annually resolved seawater temperature variability of the Sub-polar North Atlantic over the last 1000 years

    NASA Astrophysics Data System (ADS)

    Reynolds, David; Scourse, James; Hall, Ian; Nederbragt, Alexandra; Wanamaker, Alan; Halloran, Paul; Butler, Paul; Richardson, Chris; Eiríksson, Jon; Heinemeier, Jan; Luise Knudsen, Karen

    2015-04-01

    The lack of annually-resolved marine climate records spanning the last millennium constrains our understanding of the natural variability of the global climate system. We present a continuous annually-resolved reconstruction of sub-polar (N Iceland) sea water temperatures (SWT) derived from the 18O analyses of carbonate material drilled from the annually resolved growth increments contained in an absolutely dated master Arctica islandica sclerochronology spanning the period 953-2000. The calibrated SWT reconstruction contains a significant cooling trend over the period 953-1891 (0.1oC per century) and a marked warming trend over the period 1891-2000 (2.3oC per century). The underlying natural variability is controlled by solar irradiance changes modulated by volcanic forcing and internal variability. The modern SWT warming is demonstrated to lie outside the range of natural variability of the last 1000 years consistent with an anthropogenic influence.

  7. Cell growth characteristics from angle- and polarization-resolved light scattering: Prospects for two-dimensional correlation analysis

    NASA Astrophysics Data System (ADS)

    Herran Cuspinera, Roxana M.; Hore, Dennis K.

    2016-11-01

    We highlight the potential of generalized two-dimensional correlation analysis for the fingerprinting of cell growth in solution monitored by light scattering, where the synchronous and asynchronous responses serve as a sensitive marker for the effect of growth conditions on the distribution of cell morphologies. The polarization of the scattered light varies according to the cell size distribution, and so the changes in the polarization over time are an excellent indicator of the dynamic growth conditions. However, direct comparison of the polarization-, time-, and angle-resolved signals between different experiments is hindered by the subtle changes in the data, and the inability to easily adapt models to account for these differences. Using Mie scattering simulations of different growth conditions, and some preliminary experimental data for a single set of conditions, we illustrate that correlation analysis provides rapid and sensitive qualitative markers of growth characteristics.

  8. SAMRAI: A novel variably polarized angle-resolved photoemission beamline in the VUV region at UVSOR-II

    SciTech Connect

    Kimura, Shin-Ichi; Ito, Takahiro; Hosaka, Masahito; Katoh, Masahiro; Sakai, Masahiro; Nakamura, Eiken; Kondo, Naonori; Horigome, Toshio; Hayashi, Kenji; Goto, Tomohiro; Ejima, Takeo; Soda, Kazuo

    2010-05-15

    A novel variably polarized angle-resolved photoemission spectroscopy beamline in the vacuum-ultraviolet (VUV) region has been installed at the UVSOR-II 750 MeV synchrotron light source. The beamline is equipped with a 3 m long APPLE-II type undulator with horizontally/vertically linear and right/left circular polarizations, a 10 m Wadsworth type monochromator covering a photon energy range of 6-43 eV, and a 200 mm radius hemispherical photoelectron analyzer with an electron lens of a {+-}18 deg. acceptance angle. Due to the low emittance of the UVSOR-II storage ring, the light source is regarded as an entrance slit, and the undulator light is directly led to a grating by two plane mirrors in the monochromator while maintaining a balance between high-energy resolution and high photon flux. The energy resolving power (h{nu}/{Delta}h{nu}) and photon flux of the monochromator are typically 1x10{sup 4} and 10{sup 12} photons/s, respectively, with a 100 {mu}m exit slit. The beamline is used for angle-resolved photoemission spectroscopy with an energy resolution of a few meV covering the UV-to-VUV energy range.

  9. Genomic evidence for island population conversion resolves conflicting theories of polar bear evolution.

    PubMed

    Cahill, James A; Green, Richard E; Fulton, Tara L; Stiller, Mathias; Jay, Flora; Ovsyanikov, Nikita; Salamzade, Rauf; St John, John; Stirling, Ian; Slatkin, Montgomery; Shapiro, Beth

    2013-01-01

    Despite extensive genetic analysis, the evolutionary relationship between polar bears (Ursus maritimus) and brown bears (U. arctos) remains unclear. The two most recent comprehensive reports indicate a recent divergence with little subsequent admixture or a much more ancient divergence followed by extensive admixture. At the center of this controversy are the Alaskan ABC Islands brown bears that show evidence of shared ancestry with polar bears. We present an analysis of genome-wide sequence data for seven polar bears, one ABC Islands brown bear, one mainland Alaskan brown bear, and a black bear (U. americanus), plus recently published datasets from other bears. Surprisingly, we find clear evidence for gene flow from polar bears into ABC Islands brown bears but no evidence of gene flow from brown bears into polar bears. Importantly, while polar bears contributed <1% of the autosomal genome of the ABC Islands brown bear, they contributed 6.5% of the X chromosome. The magnitude of sex-biased polar bear ancestry and the clear direction of gene flow suggest a model wherein the enigmatic ABC Island brown bears are the descendants of a polar bear population that was gradually converted into brown bears via male-dominated brown bear admixture. We present a model that reconciles heretofore conflicting genetic observations. We posit that the enigmatic ABC Islands brown bears derive from a population of polar bears likely stranded by the receding ice at the end of the last glacial period. Since then, male brown bear migration onto the island has gradually converted these bears into an admixed population whose phenotype and genotype are principally brown bear, except at mtDNA and X-linked loci. This process of genome erosion and conversion may be a common outcome when climate change or other forces cause a population to become isolated and then overrun by species with which it can hybridize.

  10. NASA's Lunar Polar Ice Prospector, RESOLVE: Mission Rehearsal in Apollo Valley

    NASA Technical Reports Server (NTRS)

    Larson, William E.; Picard, Martin; Quinn, Jacqueline; Sanders, Gerald B.; Colaprete, Anthony; Elphic, Richard C.

    2012-01-01

    After the completion of the Apollo Program, space agencies didn't visit the moon for many years. But then in the 90's, the Clementine and Lunar Prospector missions returned and showed evidence of water ice at the poles. Then in 2009 the Lunar Crater Observation and Sensing Satellite indisputably showed that the Cabeus crater contained water ice and other useful volatiles. Furthermore, instruments aboard the Lunar Reconnaissance Orbiter (LRO) show evidence that the water ice may also be present in areas that receive several days of continuous sunlight each month. However, before we can factor this resource into our mission designs, we must understand the distribution and quantity of ice or other volatiles at the poles and whether it can be reasonably harvested for use as propellant or mission consumables. NASA, in partnership with the Canadian Space Agency (CSA), has been developing a payload to answer these questions. The payload is named RESOLVE. RESOLVE is on a development path that will deliver a tested flight design by the end of 2014. The team has developed a Design Reference Mission using LRO data that has RESOLVE landing near Cabeus Crater in May of2016. One of the toughest obstacles for RESOLVE's solar powered mission is its tight timeline. RESOLVE must be able to complete its objectives in the 5-7 days of available sunlight. The RESOLVE team must be able to work around obstacles to the mission timeline in real time. They can't afford to take a day off to replan as other planetary missions have done. To insure that this mission can be executed as planned, a prototype version of RESOLVE was developed this year and tested at a lunar analog site on Hawaii, known as Apollo Valley, which was once used to train the Apollo astronauts. The RESOLVE team planned the mission with the same type of orbital imagery that would be available from LRO. The simulation team prepositioned a Lander in Apollo Valley with RESOLVE on top mounted on its CSA rover. Then the mission

  11. Polarization-resolved sensing with tilted fiber Bragg gratings: theory and limits of detection

    NASA Astrophysics Data System (ADS)

    Bialiayeu, Aliaksandr; Ianoul, Anatoli; Albert, Jacques

    2015-08-01

    Polarization based sensing with tilted fiber Bragg grating (TFBG) sensors is analysed theoretically by two alternative approaches. The first method is based on tracking the grating transmission for two orthogonal states of linear polarized light that are extracted from the measured Jones matrix or Stokes vectors of the TFBG transmission spectra. The second method is based on the measurements along the system principle axes and polarization dependent loss (PDL) parameter, also calculated from measured data. It is shown that the frequent crossing of the Jones matrix eigenvalues as a function of wavelength leads to a non-physical interchange of the calculated principal axes; a method to remove this unwanted mathematical artefact and to restore the order of the system eigenvalues and the corresponding principal axes is provided. A comparison of the two approaches reveals that the PDL method provides a smaller standard deviation and therefore lower limit of detection in refractometric sensing. Furthermore, the polarization analysis of the measured spectra allows for the identification of the principal states of polarization of the sensor system and consequentially for the calculation of the transmission spectrum for any incident polarization state. The stability of the orientation of the system principal axes is also investigated as a function of wavelength.

  12. Two-Dimensional Subpicosecond Time-Resolved Fluorescence Anisotropy: Optical Kerr-Gating with a Dynamic Polarization Excitation.

    NASA Astrophysics Data System (ADS)

    Fujiwara, Takashige; Romano, Natalie C.; Modarelli, David A.; Lim, Edward C.

    2013-06-01

    With an advent of ultrafast lasers, a number of applications are widely adopted to probe photophysical and photochemical properties of a molecule that occurs in an ultrafast (femtosecond to picosecond) time scale. Intramolecular charge transfer (ICT) or proton transfer in photoexcited electron donor-acceptor (EDA) molecules, for instance, has been a topic of very extensive time-resolved studies for several decades. Time-evolution of an anisotropic property can track dipole orientations or conformational changes in their photoexcited molecular systems, which is of extreme importance to examine its structure and excited-state dynamics rather than probing an isotropic "population change".With this respect, we recently developed a subpicosecond time-resolved 2-D fluorescence anisotropy (TRFA) in which method implements a dynamic alternation of laser polarizations to excite a sample using a photoelastic modulator (PEM). In the combination of an ultrafast optical shutter (Kerr-gating) and a spectrograph that is coupled with a CCD, two signal phases so-obtained dynamically, I_{∥}( t, λ) and I_{⊥}( t, λ), provide a 2-D mapped information on both a wide range for spectra and time-resolved kinetics of photoexcited molecules of interest. From the definition of an anisotropy 2-D TRFA, r (t, λ), is given instantly and even more reliably at a single measurement. In this paper we will present benchmark tests of some target samples to establish performance of TRFA.

  13. Multiple-view spectrally resolved x-ray imaging observations of polar-direct-drive implosions on OMEGA

    SciTech Connect

    Mancini, R. C.; Johns, H. M.; Joshi, T.; Mayes, D.; Nagayama, T.; Hsu, S. C.; Baumgaertel, J. A.; Cobble, J.; Krasheninnikova, N. S.; Bradley, P. A.; Hakel, P.; Murphy, T. J.; Schmitt, M. J.; Shah, R. C.; Tregillis, I. L.; Wysocki, F. J.

    2014-12-15

    We present spatially, temporally, and spectrally resolved narrow- and broad-band x-ray images of polar-direct-drive (PDD) implosions on OMEGA. These self-emission images were obtained during the deceleration phase and bang time using several multiple monochromatic x-ray imaging instruments fielded along two or three quasi-orthogonal lines-of-sight, including equatorial and polar views. The instruments recorded images based on K-shell lines from a titanium tracer located in the shell as well as continuum emission. These observations constitute the first such data obtained for PDD implosions. The image data show features attributed to laser imprinting and zero-order hydrodynamics. Equatorial-view images show a “double bun” structure that is consistent with synthetic images obtained from post-processing 2D and 3D radiation-hydrodynamic simulations of the experiment. Polar-view images show a pentagonal, petal pattern that correlates with the PDD laser illumination used on OMEGA, thus revealing a 3D aspect of PDD OMEGA implosions not previously observed. Differences are noted with respect to a PDD experiment performed at National Ignition Facility.

  14. Vectorial spin polarization detection in multichannel spin-resolved photoemission spectroscopy using an Ir(001) imaging spin filter

    NASA Astrophysics Data System (ADS)

    Schaefer, Erik D.; Borek, Stephan; Braun, Jürgen; Minár, Ján; Ebert, Hubert; Medjanik, Katerina; Kutnyakhov, Dmytro; Schönhense, Gerd; Elmers, Hans-Joachim

    2017-03-01

    We report on spin- and angular-resolved photoemission spectroscopy using a high-resolution imaging spin filter based on a large Ir(001) crystal enhancing the effective figure of merit for spin detection by a factor of over 103 compared to standard single-channel detectors. Furthermore, we review the spin filter preparation and its lifetime. The spin filter efficiency is mapped on a broad range of scattering energies and azimuthal angles. Large spin filter efficiencies are observed for the spin component perpendicular as well as parallel to the scattering plane depending on the azimuthal orientation of the spin filter crystal. A spin rotator capable of manipulating the spin direction prior to detection complements the measurement of three observables, thus allowing for a derivation of all three components of the spin polarization vector in multichannel spin polarimetry. The experimental results nicely agree with spin-polarized low-energy electron diffraction calculations based on a fully relativistic multiple scattering method in the framework of spin-polarized density functional theory.

  15. Horizontally resolved structures of polar mesospheric echoes obtained with the Middle Atmosphere Alomar Radar System

    NASA Astrophysics Data System (ADS)

    Latteck, Ralph; Zecha, Marius; Rapp, Markus; Stober, Gunter; Singer, Werner

    2012-07-01

    Polar Mesosphere Summer Echoes have been observed in Andenes/Norway (69°N, 16°E) for more than 18 years using the Alomar SOUSY and the ALWIN VHF radars. In 2011 the Leibniz-Institute of Atmospheric Physics in Kühlungsborn completed the installation of the Middle Atmosphere Alomar Radar System ({MAARSY}). The new radar is designed for atmospheric studies from the troposphere up to the lower thermosphere, especially for the investigation of horizontal structures of polar mesospheric echoes. The system is composed of an active phased antenna consisting of 433 array elements and an identical number of transceiver modules individually controllable in frequency, phase, and output power on a pulse-to-pulse basis. This arrangement allows very high flexibility of beam forming and beam steering with a symmetric 3.6° small radar beam and arbitrary beam pointing directions down to 30° off-zenith. The monitoring of polar mesosphere echoes using a vertical pointed radar beam has been continued already during the construction period of MAARSY in order to complete the long term data base available for Andenes. Additionally first multi-beam scanning experiments using up to 97 beams quasi-simultaneously in the mesosphere have been carried out during several campaigns starting in summer 2010. Sophisticated wind analysis methods such as an extended velocity azimuth display have been applied to retrieve additional parameters from the wind field, e.g. horizontal divergence, vertical velocity, stretching and shearing deformation. The results provide a first insight into the strong horizontal variability of scattering structures occurring in the polar mesosphere over Andenes during summer and winter time. The implementation of interferometric radar imaging methods offers further improvement of the horizontal and the vertical resolution.

  16. Polarization-resolved simulations of multiple-order rainbows using realistic raindrop shapes

    NASA Astrophysics Data System (ADS)

    Haußmann, Alexander

    2016-05-01

    This paper presents selected results of a simulation study of the first five (primary-quinary) rainbow orders based on a realistic, size-dependent shape model for falling raindrops, taking into account that the drops' bottom part is flattened to higher degree than the dome-like top part. Moreover, broad drop size distributions are included in the simulations, as it is one goal of this paper to analyze, whether the predicted amplification and attenuation patterns for higher-order rainbows, as derived from previous simulations with monodisperse drop sizes, will still be pronounced under the conditions of natural rainfall. Secondly, deviations of the multiple rainbow orders' polarization state from the reference case of spherical drops are discussed. It is shown that each rainbow order may contain a small amount of circularly polarized light due to total internal reflections. Thirdly, it is investigated, how the conditions that generate twinned primary rainbows will affect the higher orders. For the simulations, geometric-optic ray tracing of the full Stokes vector as well as an approximate approach using appropriately shifted Debye series data is applied.

  17. Time- and polarization-resolved cellular autofluorescence towards quantitative biochemistry on living cells

    NASA Astrophysics Data System (ADS)

    Alfveby, John; TImerman, Randi; Soto Velasquez, Monica P.; Wickramasinghe, Dhanushka W. P. M.; Bartusek, Jillian; Heikal, Ahmed A.

    2014-09-01

    Native coenzymes such as the reduced nicotinamide adenine dinucleotide (NADH) and oxidized flavin adenine dinucleotide play pivotal roles in energy metabolism and a myriad of biochemical reactions in living cells/tissues. These coenzymes are naturally fluorescent and, therefore, have the potential to serve as intrinsic biomarkers for mitochondrial activities, programmed cell death (apoptosis), oxidative stress, aging, and neurodegenerative disease. In this contribution, we employ two-photon fluorescence lifetime imaging microscopy (FLIM) and time-resolved anisotropy imaging of intracellular NADH for quantitative, non-invasive biochemistry on living cells in response to hydrogenperoxide- induced oxidative stress. In contrast with steady-state one-photon, UV-excited autofluorescence, two-photon FLIM is sensitive to both molecular conformation and stimuli-induced changes in the local environment in living cells with minimum photodamage and inherently enhanced spatial resolution. On the other hand, time-resolved, two-photon anisotropy imaging of cellular autofluorescence allows for quantitative assessment of binding state and environmental restrictions on the tumbling mobility of intrinsic NADH. Our measurements reveal that free and enzyme-bound NADH exist at equilibrium, with a dominant autofluorescence contribution of the bound fraction in living cells. Parallel studies on NADH-enzyme binding in controlled environments serve as a point of reference in analyzing autofluorescence in living cells. These autofluorescence-based approaches complement the conventional analytical biochemistry methods that require the destruction of cells/tissues, while serving as an important step towards establishing intracellular NADH as a natural biomarker for monitoring changes in energy metabolism and redox state of living cells in response to environmental hazards.

  18. Resolving spectral information from time domain induced polarization data through 2-D inversion

    NASA Astrophysics Data System (ADS)

    Fiandaca, Gianluca; Ramm, James; Binley, Andrew; Gazoty, Aurélie; Christiansen, Anders Vest; Auken, Esben

    2013-02-01

    Field-based time domain (TD) induced polarization (IP) surveys are usually modelled by taking into account only the integral chargeability, thus disregarding spectral content. Furthermore, the effect of the transmitted waveform is commonly neglected, biasing inversion results. Given these limitations of conventional approaches, a new 2-D inversion algorithm has been developed using the full voltage decay of the IP response, together with an accurate description of the transmitter waveform and receiver transfer function. This allows reconstruction of the spectral information contained in the TD decay series. The inversion algorithm is based around a 2-D complex conductivity kernel that is computed over a range of frequencies and converted to the TD through a fast Hankel transform. Two key points in the implementation ensure that computation times are minimized. First, the speed of the Jacobian computation, time transformed from frequency domain through the same transformation adopted for the forward response is optimized. Secondly, the reduction of the number of frequencies where the forward response and Jacobian are calculated: cubic splines are used to interpolate the responses to the frequency sampling necessary in the fast Hankel transform. These features, together with parallel computation, ensure inversion times comparable with those of direct current algorithms. The algorithm has been developed in a laterally constrained inversion scheme, and handles both smooth and layered inversions; the latter being helpful in sedimentary environments, where quasi-layered models often represent the actual geology more accurately than smooth minimum-structure models. In the layered inversion approach, a general method to derive the thickness derivative from the complex conductivity Jacobian is also proposed. One synthetic example of layered inversion and one field example of smooth inversion show the capability of the algorithm and illustrates a complete uncertainty

  19. Polarization resolved electric field measurements on plasma bullets in N2 using four-wave mixing

    NASA Astrophysics Data System (ADS)

    van der Schans, Marc; Boehm, Patrick; Nijdam, Sander; Ijzerman, Wilbert; Czarnetzki, Uwe

    2016-09-01

    Atmospheric pressure plasma jets generated by kHz AC or pulsed DC voltages typically consist of discrete guided ionization waves called plasma bullets. In this work, the electric field of plasma bullets generated in a pulsed DC jet with N2 as feed gas is investigated using the four-wave mixing method. In this diagnostic two laser beams, where one is Stokes shifted from the other, non-linearly interact with the N2 molecules and the bullet's electric field. As a result of the interaction a coherent anti-Stokes Raman scattered (CARS) beam and an infrared beam are generated from which the electric field can be determined. Compared to emission-based methods, this technique has the advantage of being able to also probe the electric field in regions around the plasma bullet where no photons are emitted. The four-wave mixing method and its analysis have been adapted to work with the non-uniform electric field of plasma bullets. In addition, an ex-situ calibration procedure using an electrode geometry different from the discharge geometry has been developed. An experimentally obtained radial profile of the axial electric field component of a plasma bullet in N2 is presented. The position of this profile is related to the location of the propagating bullet from temporally resolved images.

  20. Resolving stress tensor components in space from polarized Raman spectra: polycrystalline alumina.

    PubMed

    Pezzotti, Giuseppe; Zhu, Wenliang

    2015-01-28

    A method of Raman spectroscopic analysis has been proposed for evaluating tensorial stress fields stored in alumina polycrystals with a corundum structure (α-Al2O3). Raman selection rules for all the vibrational modes of the structure were expanded into explicit functions of both 3 Euler angles in space and 4 Raman tensor elements (RTE) of corundum. A theoretical treatment was then worked out according to the phonon deformation potential (PDP) formalism, which explicitly expressed the changes in force constants under stress in matricial form. Close-form solutions could be obtained for the matrix eigenvalues as a function of 9 unknown variables, namely 6 independent stress tensor components and 3 Euler angles in space, the latter parameters being representatives of local crystal orientation. Successively, two separate sets of Raman calibration experiments were performed for the determination of both RTE and PDP constants of the corundum structure of alumina. Calibration experiments provided a quantitative frame to the newly developed Raman formalism. Polarized Raman spectra were systematically recorded in both single-crystalline and polycrystalline samples, with both A1g and Eg vibrational bands being characterized. Regarding polycrystalline samples, a validation of the proposed Raman method could be done through a comparison between Raman and fluorescence data collected at the same locations across an alumina/metal interface embedded in a steeply graded residual stress field.

  1. A One Billion Year Martian Climate Model: The Importance of Seasonally Resolved Polar Caps and the Role of Wind

    NASA Technical Reports Server (NTRS)

    Armstrong, J. C.; Leovy, C. B.; Quinn, T. R.; Haberle, R. M.; Schaeffer, J.

    2003-01-01

    Wind deflation and deposition are powerful agents of surface change in the present Mars climate regime. Recent studies indicate that, while the distribution of regions of potential deflation (or erosion) and deposition is remarkably insensitive to changes in orbital parameters (obliquity, timing of perihelion passage, etc.), rates of aeolian surface modification may be highly sensitive to these parameters even if the atmospheric mass remains constant. But previous work suggested the atmospheric mass is likely to be sensitive to obliquity, especially if a significant mass of carbon dioxide can be stored in the regolith or deposited in the form of massive polar caps. Deflation and erosion are highly sensitive to surface pressure, so feedback between orbit variations and surface pressure can greatly enhance the sensitivity of aeolian modification rates to orbital parameters. We used statistics derived from a 1 Gyr orbital integration of the spin axis of Mars, coupled with 3D general circulation models (GCMs) at a variety of orbital conditions and pressures, to explore this feedback. We also employed a seasonally resolved 1D energy balance model to illuminate the gross characteristics of the longterm atmospheric evolution, wind erosion and deposition over one billion years. We find that seasonal polar cycles have a critical influence on the ability for the regolith to release CO2 at high obliquities, and find that the atmospheric CO2 actually decreases at high obliquities due to the cooling effect of polar deposits at latitudes where seasonal caps form. At low obliquity, the formation of massive, permanent polar caps depends critically on the values of the frost albedo, A(sub frost), and frost emissivity, E(sub frost). Using our 1D model with values of A(sub frost) = 0.67 and E(sub frost) = 0.55, matched to the NASA Ames GCM results, we find that permanent caps only form at low obliquities (< 10 degrees). Thus, contrary to expectations, the Martian atmospheric pressure

  2. Seasonal and solar-cycle variations of DP-type polar magnetic fields resolved via EOF analysis

    NASA Astrophysics Data System (ADS)

    Shore, Robert; Freeman, Mervyn; Wild, James; Dorrian, Gareth; Gjerloev, Jesper

    2016-04-01

    We describe our application of the Empirical Orthogonal Function (EOF) method to characterise and separate contributions to the variability of the Earth's external magnetic field (EMF) in the northern polar region, using ground magnetometer measurements. The EOF method analyses the spatio-temporal co-variance of the data to decompose it into dynamically distinct modes (each mode is a pair of spatial and temporal basis vectors). Briefly, the benefits of this analysis method are firstly that a small number of the modes can cumulatively represent most of the variance of the original data, and secondly that the basis vectors are defined by the data. Hence, the structure of the EMF is resolved compactly without a priori assumptions, in contrast to other decomposition methods such as Fourier and spherical harmonic expansions. We present the modes from 11 years (1997 - 2008) of magnetic vector data at 5 minutes resolution, recently collated by the SuperMAG archive of observatory and variometer data. Despite the sparse and irregular station distribution, a complete spatial morphology of the EMF is achieved using a self-consistent iterative infill method. Using a comparison of the temporal behaviour of the modes alongside independent measures of solar-terrestrial coupling, we demonstrate that the leading three modes describe the well-known Disturbance-Polar currents types 2 and 1 (DP2, DP1) and the system of cusp currents (DPY). These three modes account for the majority of the variance of the data - other modes describe the spatial motions of these current systems. The variation in the DP2, DP1 and DPY currents throughout the last solar cycle is presented, and the utility of this database of magnetic perturbations (to which further analysis methods can be applied) is highlighted.

  3. Polarization-Resolved Raman Study of Bulk-like and Davydov-Induced Vibrational Modes of Exfoliated Black Phosphorus.

    PubMed

    Phaneuf-L'Heureux, Anne-Laurence; Favron, Alexandre; Germain, Jean-Francis; Lavoie, Patrick; Desjardins, Patrick; Leonelli, Richard; Martel, Richard; Francoeur, Sebastien

    2016-12-14

    Owing to its crystallographic structure, black phosphorus is one of the few 2D materials expressing strongly anisotropic optical, transport, and mechanical properties. We report on the anisotropy of electron-phonon interactions through a polarization-resolved Raman study of the four vibrational modes of atomically thin black phosphorus (2D phosphane): the three bulk-like modes Ag(1), B2g, and Ag(2) and the Davydov-induced mode labeled Ag(B2u). The complex Raman tensor elements reveal that the relative variation in permittivity of all Ag modes is irrespective of the atomic motion involved lowest along the zigzag direction, the basal anisotropy of these variations is most pronounced for Ag(2) and Ag(B2u), and interlayer interactions in multilayer samples lead to reduced anisotropy. The bulk-forbidden Ag(B2u) mode appears for n ≥ 2 and quickly subsides in thicker layers. It is assigned to a Davydov-induced IR to Raman conversion of the bulk IR mode B2u and exhibits characteristics similar to Ag(2). Although this mode is expected to be weak, an electronic resonance significantly enhances its Raman efficiency such that it becomes a dominant mode in the spectrum of bilayer 2D phosphane.

  4. Motion-artifact-robust, polarization-resolved second-harmonic-generation microscopy based on rapid polarization switching with electro-optic Pockells cell and its application to in vivo visualization of collagen fiber orientation in human facial skin.

    PubMed

    Tanaka, Yuji; Hase, Eiji; Fukushima, Shuichiro; Ogura, Yuki; Yamashita, Toyonobu; Hirao, Tetsuji; Araki, Tsutomu; Yasui, Takeshi

    2014-04-01

    Polarization-resolved second-harmonic-generation (PR-SHG) microscopy is a powerful tool for investigating collagen fiber orientation quantitatively with low invasiveness. However, the waiting time for the mechanical polarization rotation makes it too sensitive to motion artifacts and hence has hampered its use in various applications in vivo. In the work described in this article, we constructed a motion-artifact-robust, PR-SHG microscope based on rapid polarization switching at every pixel with an electro-optic Pockells cell (PC) in synchronization with step-wise raster scanning of the focus spot and alternate data acquisition of a vertical-polarization-resolved SHG signal and a horizontal-polarization-resolved one. The constructed PC-based PR-SHG microscope enabled us to visualize orientation mapping of dermal collagen fiber in human facial skin in vivo without the influence of motion artifacts. Furthermore, it implied the location and/or age dependence of the collagen fiber orientation in human facial skin. The robustness to motion artifacts in the collagen orientation measurement will expand the application scope of SHG microscopy in dermatology and collagen-related fields.

  5. [Is superstitious behavior more easily acquired by negative reinforcement schedules than positive reinforcement schedules? Examinations of the polarity and the duration of a consequence].

    PubMed

    Hori, Mayuko; Numata, Keitaro; Nakajima, Sadahiko

    2014-02-01

    This study investigated the effects of positive and negative reinforcement on superstitious behaviors. Participants were instructed to produce the word "GOOD" on a computer display (positive reinforcement condition) or to remove the word "BAD" (negative reinforcement condition) by pressing any of six keys. The words GOOD or BAD were presented at fixed-time intervals regardless of the participant's responses. In Experiment 1, only participants exposed to the negative reinforcement condition acquired superstitious behaviors. However, the observed asymmetry may not have been due to the polarity of consequences (positive vs. negative) but instead to the amount of time of goal states, because the period of the absence of BAD was longer than the period of the presence of GOOD. Experiment 2 varied the duration of word presentations to match the period of goal state between the positive and negative reinforcement conditions, and found that participants acquired superstitious behaviors equally under the two conditions. These results indicate that the duration of a consequence rather than its polarity is a critical factor controlling superstitious behaviors. The theoretical relationship between superstitious behavior and the illusion of control is discussed.

  6. Time-resolved x-ray magnetic circular dichroism study of ultrafast demagnetization in a CoPd ferromagnetic film excited by circularly polarized laser pulse

    NASA Astrophysics Data System (ADS)

    López-Flores, Víctor; Arabski, Jacek; Stamm, Christian; Halté, Valérie; Pontius, Niko; Beaurepaire, Eric; Boeglin, Christine

    2012-07-01

    The magnetization dynamics of CoPd films excited by circularly polarized ultrashort laser pulses is studied by time-resolved x-ray magnetic circular dichroism. In those films the ultrafast dynamics measured at the Co-L3 edge is strongly sensitive to the orbital magnetic moment Lz. The amount of angular momentum transferred by the circularly polarized ultrashort laser pulses to the ferromagnetic films is evaluated to ±0.1 ℏ/atom, which is above the detection limit of the experiment. Despite this, no polarization-dependent difference on the magnetization dynamics could be evidenced. These results are explained by ultrafast electronic relaxation mechanisms of the transferred angular momentum, faster than ˜100 fs. This experiment sets the methodology as well as an upper time limit for determination of angular momentum relaxation processes.

  7. Polarization-resolved photoluminescence study of individual GaN nanowires grown by catalyst-free molecular beam epitaxy

    NASA Astrophysics Data System (ADS)

    Schlager, John B.; Sanford, Norman A.; Bertness, Kris A.; Barker, Joy M.; Roshko, Alexana; Blanchard, Paul T.

    2006-05-01

    Polarization- and temperature-dependent photoluminescence (PL) measurements were performed on individual GaN nanowires. These were grown by catalyst-free molecular beam epitaxy on Si(111) substrates, ultrasonically removed, and subsequently dispersed on sapphire substrates. The wires were typically 5-10μm in length, c-axis oriented, and 30-100nm in diameter. Single wires produced sufficient emission intensity to enable high signal-to-noise PL data. Polarized PL spectra differed for the σ and π polarization cases, illustrating the polarization anisotropy of the exciton emission associated with high-quality wurtzite GaN. This anisotropy in PL emission persisted even up to room temperature (4-296K). Additionally, the nanowire PL varied with excitation intensity and with (325nm) pump exposure time.

  8. Temporally and spatially resolved photoluminescence investigation of (112{sup ¯}2) semi-polar InGaN/GaN multiple quantum wells grown on nanorod templates

    SciTech Connect

    Liu, B.; Smith, R.; Athanasiou, M.; Yu, X.; Bai, J.; Wang, T.

    2014-12-29

    By means of time-resolved photoluminescence (PL) and confocal PL measurements, temporally and spatially resolved optical properties have been investigated on a number of In{sub x}Ga{sub 1−x}N/GaN multiple-quantum-well (MQW) structures with a wide range of indium content alloys from 13% to 35% on (112{sup ¯}2) semi-polar GaN with high crystal quality, obtained through overgrowth on nanorod templates. With increasing indium content, the radiative recombination lifetime initially increases as expected, but decreases if the indium content further increases to 35%, corresponding to emission in the green spectral region. The reduced radiative recombination lifetime leads to enhanced optical performance for the high indium content MQWs as a result of strong exciton localization, which is different from the behaviour of c-plane InGaN/GaN MQWs, where quantum confined Stark effect plays a dominating role in emission process.

  9. Angle-resolved photoemission with circularly polarized light in the nodal mirror plane of underdoped Bi2Sr2CaCu2O8+δ superconductor

    DOE PAGES

    He, Junfeng; Mion, Thomas R.; Gao, Shang; ...

    2016-10-31

    Unraveling the nature of pseudogap phase in high-temperature superconductors holds the key to understanding their superconducting mechanisms and potentially broadening their applications via enhancement of their superconducting transition temperatures. Angle-resolved photoemission spectroscopy (ARPES) experiments using circularly polarized light have been proposed to detect possible symmetry breaking state in the pseudogap phase of cuprates. Here, the presence (absence) of an electronic order which breaks mirror symmetry of the crystal would in principle induce a finite (zero) circular dichroism in photoemission. Different orders breaking reflection symmetries about different mirror planes can also be distinguished by the momentum dependence of the measured circularmore » dichroism.« less

  10. Polar Second-Harmonic Imaging to Resolve Pure and Mixed Crystal Phases along GaAs Nanowires.

    PubMed

    Timofeeva, Maria; Bouravleuv, Alexei; Cirlin, George; Shtrom, Igor; Soshnikov, Ilya; Reig Escalé, Marc; Sergeyev, Anton; Grange, Rachel

    2016-10-12

    In this work, we report an optical method for characterizing crystal phases along single-semiconductor III-V nanowires based on the measurement of polarization-dependent second-harmonic generation. This powerful imaging method is based on a per-pixel analysis of the second-harmonic-generated signal on the incoming excitation polarization. The dependence of the second-harmonic generation responses on the nonlinear second-order susceptibility tensor allows the distinguishing of areas of pure wurtzite, zinc blende, and mixed and rotational twins crystal structures in individual nanowires. With a far-field nonlinear optical microscope, we recorded the second-harmonic generation in GaAs nanowires and precisely determined their various crystal structures by analyzing the polar response for each pixel of the images. The predicted crystal phases in GaAs nanowire are confirmed with scanning transmission electron and high-resolution transmission electron measurements. The developed method of analyzing the nonlinear polar response of each pixel can be used for an investigation of nanowire crystal structure that is quick, sensitive to structural transitions, nondestructive, and on-the-spot. It can be applied for the crystal phase characterization of nanowires built into optoelectronic devices in which electron microscopy cannot be performed (for example, in lab-on-a-chip devices). Moreover, this method is not limited to GaAs nanowires but can be used for other nonlinear optical nanostructures.

  11. Intrinsic spin polarized electronic structure of CrO{sub 2} epitaxial film revealed by bulk-sensitive spin-resolved photoemission spectroscopy

    SciTech Connect

    Fujiwara, Hirokazu; Sunagawa, Masanori; Kittaka, Tomoko; Terashima, Kensei; Wakita, Takanori; Muraoka, Yuji; Yokoya, Takayoshi

    2015-05-18

    We have performed bulk-sensitive spin-resolved photoemission spectroscopy in order to clarify the intrinsic spin-resolved electronic states of half-metallic ferromagnet CrO{sub 2}. We used CrO{sub 2} epitaxial films on TiO{sub 2}(100), which shows a peak at 1 eV with a clear Fermi edge, consistent with the bulk-sensitive PES spectrum for CrO{sub 2}. In spin-resolved spectra at 40 K, while the Fermi edge was observed in the spin up (majority spin) state, no states at the Fermi level (E{sub F}) with an energy gap of 0.5 eV below E{sub F} were observed in the spin down (minority spin) state. At 300 K, the gap in the spin down state closes. These results are consistent with resistivity measurements and magnetic hysteresis curves of the fabricated CrO{sub 2} film, constituting spectroscopic evidence for the half-metallicity of CrO{sub 2} at low temperature and reducing the spin polarization at room temperature. We also discuss the electron correlation effects of Cr 3d.

  12. A novel model on time-resolved photoluminescence measurements of polar InGaN/GaN multi-quantum-well structures

    PubMed Central

    Xing, Yuchen; Wang, Lai; Yang, Di; Wang, Zilan; Hao, Zhibiao; Sun, Changzheng; Xiong, Bing; Luo, Yi; Han, Yanjun; Wang, Jian; Li, Hongtao

    2017-01-01

    Based on carrier rate equation, a new model is proposed to explain the non-exponential nature of time-resolved photoluminescence (TRPL) decay curves in the polar InGaN/GaN multi-quantum-well structures. From the study of TRPL curves at different temperatures, it is found that both radiative and non-radiative recombination coefficients vary from low temperature to room temperature. The variation of the coefficients is compatible with the carrier density of states distribution as well as the carrier localization process. These results suggest that there is a novel method to calculate the internal quantum efficiency, which is a complement to the traditional one based on temperature dependent photoluminescence measurement. PMID:28327629

  13. A novel model on time-resolved photoluminescence measurements of polar InGaN/GaN multi-quantum-well structures

    NASA Astrophysics Data System (ADS)

    Xing, Yuchen; Wang, Lai; Yang, Di; Wang, Zilan; Hao, Zhibiao; Sun, Changzheng; Xiong, Bing; Luo, Yi; Han, Yanjun; Wang, Jian; Li, Hongtao

    2017-03-01

    Based on carrier rate equation, a new model is proposed to explain the non-exponential nature of time-resolved photoluminescence (TRPL) decay curves in the polar InGaN/GaN multi-quantum-well structures. From the study of TRPL curves at different temperatures, it is found that both radiative and non-radiative recombination coefficients vary from low temperature to room temperature. The variation of the coefficients is compatible with the carrier density of states distribution as well as the carrier localization process. These results suggest that there is a novel method to calculate the internal quantum efficiency, which is a complement to the traditional one based on temperature dependent photoluminescence measurement.

  14. A novel model on time-resolved photoluminescence measurements of polar InGaN/GaN multi-quantum-well structures.

    PubMed

    Xing, Yuchen; Wang, Lai; Yang, Di; Wang, Zilan; Hao, Zhibiao; Sun, Changzheng; Xiong, Bing; Luo, Yi; Han, Yanjun; Wang, Jian; Li, Hongtao

    2017-03-22

    Based on carrier rate equation, a new model is proposed to explain the non-exponential nature of time-resolved photoluminescence (TRPL) decay curves in the polar InGaN/GaN multi-quantum-well structures. From the study of TRPL curves at different temperatures, it is found that both radiative and non-radiative recombination coefficients vary from low temperature to room temperature. The variation of the coefficients is compatible with the carrier density of states distribution as well as the carrier localization process. These results suggest that there is a novel method to calculate the internal quantum efficiency, which is a complement to the traditional one based on temperature dependent photoluminescence measurement.

  15. Depth-resolved birefringence imaging of the primate retinal nerve fiber layer using polarization-sensitive OCT

    NASA Astrophysics Data System (ADS)

    Kemp, Nathaniel J.; Park, Jesung; Marsack, Jason D.; Dave, Digant P.; Parekh, Sapun H.; Milner, Thomas E.; Rylander, Henry G., III

    2002-06-01

    Imaging the optical phase retardation per unit depth (OPR/UD) in the retinal nerve fiber layer (RNFL) may aid in glaucoma diagnosis. Polarization Sensitive Optical Coherence Tomography (PSOCT) was used to record in vivo high-resolution images of the RNFL in two cynomologous monkeys. The depth variation in the Stokes vector of reflected light was used to calculate the OPR/UD as a function of RNFL position. OPR/UD decreased from 35 degree(s)/100 micrometers near the optic nerve to 5 degree(s)/100 micrometers at a location 600 micrometers superior to the optic nerve. Variation of OPR/UD in the RNFL with retinal position demonstrates a change in birefringence for different densities of ganglion cell axons. PSOCT may be useful for noninvasive determination of RNFL thickness and fiber density.

  16. Development of a polarization resolved spectroscopic diagnostic for measurements of the magnetic field in the Caltech coaxial magnetized plasma jet experiment

    NASA Astrophysics Data System (ADS)

    Shikama, Taiichi; Bellan, Paul M.

    2011-11-01

    Measurements of the magnetic field strength in current-carrying magnetically confined plasmas are necessary for understanding the underlying physics governing the dynamical behavior. Such a measurement would be particularly useful in the Caltech coaxial magnetized plasma gun, an experiment used for fundamental studies relevant to spheromak formation, astrophysical jet formation/propagation, solar coronal physics, and the general behavior of twisted magnetic flux tubes that intercept a boundary. In order to measure the field strength in the Caltech experiment, a non-perturbing spectroscopic method is being implemented to observe the Zeeman splitting in the emission spectra. The method is based on polarization-resolving spectroscopy of the Zeeman-split σ components, a technique previously used in both solar and laboratory plasmas. We have designed and constructed an optical system that can simultaneously detect left- and right-circularly polarized emission with both high throughput and small extinction ratio. The system will be used on the 489.5 nm NII line, chosen because of its simple Zeeman structure and minimal Stark broadening.

  17. Structure of collagen adsorbed on a model implant surface resolved by polarization modulation infrared reflection-absorption spectroscopy

    NASA Astrophysics Data System (ADS)

    Brand, Izabella; Habecker, Florian; Ahlers, Michael; Klüner, Thorsten

    2015-03-01

    The polarization modulation infrared reflection-absorption spectra of collagen adsorbed on a titania surface and quantum chemical calculations are used to describe components of the amide I mode to the protein structure at a sub-molecular level. In this study, imino acid rich and poor fragments, representing the entire collagen molecule, are taken into account. The amide I mode of the collagen triple helix is composed of three absorption bands which involve: (i) (∼1690 cm-1) the Cdbnd O stretching modes at unhydrated groups, (ii) (1655-1673 cm-1) the Cdbnd O stretching at carbonyl groups at imino acids and glycine forming intramolecular hydrogen bonds with H atoms at both NH2 and, unusual for proteins, CH2 groups at glycine at a neighbouring chain and (iii) (∼1640 cm-1) the Cdbnd O stretching at carbonyl groups forming hydrogen bonds between two, often charged, amino acids as well as hydrogen bonds to water along the entire helix. The IR spectrum of films prepared from diluted solutions (c < 50 μg ml-1) corresponds to solution spectra indicating that native collagen molecules interact with water adsorbed on the titania surface. In films prepared from solutions (c ⩾ 50 μg ml-1) collagen multilayers are formed. The amide I mode is blue-shifted by 18 cm-1, indicating that intramolecular hydrogen bonds at imino acid rich fragments are weakened. Simultaneous red-shift of the amide A mode implies that the strength of hydrogen bonds at the imino acid poor fragments increases. Theoretically predicted distortion of the collagen structure upon adsorption on the titania surface is experimentally confirmed.

  18. Structure of collagen adsorbed on a model implant surface resolved by polarization modulation infrared reflection-absorption spectroscopy.

    PubMed

    Brand, Izabella; Habecker, Florian; Ahlers, Michael; Klüner, Thorsten

    2015-03-05

    The polarization modulation infrared reflection-absorption spectra of collagen adsorbed on a titania surface and quantum chemical calculations are used to describe components of the amide I mode to the protein structure at a sub-molecular level. In this study, imino acid rich and poor fragments, representing the entire collagen molecule, are taken into account. The amide I mode of the collagen triple helix is composed of three absorption bands which involve: (i) (∼1690cm(-1)) the CO stretching modes at unhydrated groups, (ii) (1655-1673cm(-1)) the CO stretching at carbonyl groups at imino acids and glycine forming intramolecular hydrogen bonds with H atoms at both NH2 and, unusual for proteins, CH2 groups at glycine at a neighbouring chain and (iii) (∼1640cm(-1)) the CO stretching at carbonyl groups forming hydrogen bonds between two, often charged, amino acids as well as hydrogen bonds to water along the entire helix. The IR spectrum of films prepared from diluted solutions (c<50μgml(-1)) corresponds to solution spectra indicating that native collagen molecules interact with water adsorbed on the titania surface. In films prepared from solutions (c⩾50μgml(-1)) collagen multilayers are formed. The amide I mode is blue-shifted by 18cm(-1), indicating that intramolecular hydrogen bonds at imino acid rich fragments are weakened. Simultaneous red-shift of the amide A mode implies that the strength of hydrogen bonds at the imino acid poor fragments increases. Theoretically predicted distortion of the collagen structure upon adsorption on the titania surface is experimentally confirmed.

  19. Development of Multi-Field of view-Multiple-Scattering-Polarization Lidar : analysis of angular resolved backscattered signals

    NASA Astrophysics Data System (ADS)

    Makino, T.; Okamoto, H.; Sato, K.; Tanaka, K.; Nishizawa, T.; Sugimoto, N.; Matsui, I.; Jin, Y.; Uchiyama, A.; Kudo, R.

    2014-12-01

    We have developed a new type of ground-based lidar, Multi-Field of view-Multiple-Scattering-Polarization Lidar (MFMSPL), to analyze multiple scattering contribution due to low-level clouds. One issue of the ground based lidar is the limitation of optical thickness of about 3 due to the strong attenuation in the lidar signals so that only the cloud bottom part can be observed. In order to overcome the problem, we have proposed the MFMSPL that has been designed to observe similar degree of multiple scattering contribution expected from space-borne lidar CALIOP on CALIPSO satellite. The system consists of eight detectors; four telescopes for parallel channels and four for perpendicular channels. The four pairs of telescope have been mounted with four different off-beam angles, ranging from -5 to 35mrad, where the angle is defined as the one between the direction of laser beam and the direction of telescope. Consequently, similar large foot print (100m) as CALIOP can be achieved in the MFMSPL observations when the altitude of clouds is located at about 1km. The use of multi-field of views enables to measure depolarization ratio from optically thick clouds. The outer receivers attached with larger angles generally detect backscattered signals from clouds located at upper altitudes due to the enhanced multiple scattering compared with the inner receiver that detects signals only from cloud bottom portions. Therefore the information of cloud microphysics from optically thicker regions is expected by the MFMSPL observations compared with the conventional lidar with small FOV. The MFMSPL have been continuously operated in Tsukuba, Japan since June 2014.Initial analyses have indicated expected performances from the theoretical estimation by backward Monte-Carlo simulations. The depolarization ratio from deeper part of the clouds detected by the receiver with large off-beam angle showed much larger values than those from the one with small angle. The calibration procedures

  20. Electronic transitions and heterogeneity of the bacteriophytochrome Pr absorption band: An angle balanced polarization resolved femtosecond VIS pump-IR probe study.

    PubMed

    Linke, Martin; Yang, Yang; Zienicke, Benjamin; Hammam, Mostafa A S; von Haimberger, Theodore; Zacarias, Angelica; Inomata, Katsuhiko; Lamparter, Tilman; Heyne, Karsten

    2013-10-15

    Photoisomerization of biliverdin (BV) chromophore triggers the photoresponse in native Agp1 bacteriophytochrome. We discuss heterogeneity in phytochrome Pr form to account for the shape of the absorption profile. We investigated different regions of the absorption profile by angle balanced polarization resolved femtosecond VIS pump-IR probe spectroscopy. We studied the Pr form of Agp1 with its natural chromophore and with a sterically locked 18Et-BV (locked Agp1). We followed the dynamics and orientations of the carbonyl stretching vibrations of ring D and ring A in their ground and electronically excited states. Photoisomerization of ring D is reflected by strong signals of the ring D carbonyl vibration. In contrast, orientational data on ring A show no rotation of ring A upon photoexcitation. Orientational data allow excluding a ZZZasa geometry and corroborates a nontwisted ZZZssa geometry of the chromophore. We found no proof for heterogeneity but identified a new, to our knowledge, electronic transition in the absorption profile at 644 nm (S0→S2). Excitation of the S0→S2 transition will introduce a more complex photodynamics compared with S0→S1 transition. Our approach provides fundamental information on disentanglement of absorption profiles, identification of chromophore structures, and determination of molecular groups involved in the photoisomerization process of photoreceptors.

  1. Macrophages are recruited to hypoxic tumor areas and acquire a Pro-Angiogenic M2-Polarized phenotype via hypoxic cancer cell derived cytokines Oncostatin M and Eotaxin

    PubMed Central

    Tripathi, Chakrapani; Tewari, Brij Nath; Kanchan, Ranjana Kumari; Baghel, Khemraj Singh; Nautiyal, Naveen; Shrivastava, Richa; Kaur, Harbeer; Bhatt, Madan Lal Bramha; Bhadauria, Smrati

    2014-01-01

    TAMs, a unique and distinct M2-skewed myeloid population of tumor stroma, exhibiting pro-tumor functions is fast emerging as a potential target for anti-cancer immunotherapy. Macrophage-recruitment and M2-polarization represent key TAMs-related phenomenon that are amenable to therapeutic intervention. However successful translation of these approaches into effective therapeutic regimen requires better characterization of tumor-microenvironment derived signals that regulate macrophage recruitment and their polarization. Owing to hypoxic milieu being a persistent feature of tumor-microenvironment and a major contributor to malignancy and treatment resistance, the current study was planned with an aim to decipher tumor cell responses to hypoxia vis-a-vis macrophage homing and phenotype switching. Here, we show that hypoxia-primed cancer cells chemoattract and polarize macrophages to pro-angiogenic M2-polarized subtype via Eotaxin and Oncostatin M. Concordantly, hypoxic regions of human breast-cancer specimen exhibited elevated Eotaxin and Oncostatin M levels with concurrently elevated M2-macrophage content. Blockade of Eotaxin/Oncostatin M not only prevented hypoxic breast-cancer cells from recruiting and polarizing macrophages towards an M2-polarized phenotype and retarded tumor progression in 4T1/BALB/c-syngenic-mice-model of breast-cancer but also enhanced the efficacy of anti-angiogenic Bevacizumab. The findings established these two cytokines as novel targets for devising effective anticancer therapy particularly for tumors that are refractory or develop resistance to anti-angiogenic therapeutics. PMID:25051364

  2. A simple approach to spectrally resolved fluorescence and bright field microscopy over select regions of interest

    PubMed Central

    Dahlberg, Peter D.; Boughter, Christopher T.; Faruk, Nabil F.; Hong, Lu; Koh, Young Hoon; Reyer, Matthew A.; Sherani, Aiman; Hammond, Adam T.

    2016-01-01

    A standard wide field inverted microscope was converted to a spatially selective spectrally resolved microscope through the addition of a polarizing beam splitter, a pair of polarizers, an amplitude-mode liquid crystal-spatial light modulator, and a USB spectrometer. The instrument is capable of simultaneously imaging and acquiring spectra over user defined regions of interest. The microscope can also be operated in a bright-field mode to acquire absorption spectra of micron scale objects. The utility of the instrument is demonstrated on three different samples. First, the instrument is used to resolve three differently labeled fluorescent beads in vitro. Second, the instrument is used to recover time dependent bleaching dynamics that have distinct spectral changes in the cyanobacteria, Synechococcus leopoliensis UTEX 625. Lastly, the technique is used to acquire the absorption spectra of CH3NH3PbBr3 perovskites and measure differences between nanocrystal films and micron scale crystals. PMID:27910631

  3. A simple approach to spectrally resolved fluorescence and bright field microscopy over select regions of interest

    NASA Astrophysics Data System (ADS)

    Dahlberg, Peter D.; Boughter, Christopher T.; Faruk, Nabil F.; Hong, Lu; Koh, Young Hoon; Reyer, Matthew A.; Shaiber, Alon; Sherani, Aiman; Zhang, Jiacheng; Jureller, Justin E.; Hammond, Adam T.

    2016-11-01

    A standard wide field inverted microscope was converted to a spatially selective spectrally resolved microscope through the addition of a polarizing beam splitter, a pair of polarizers, an amplitude-mode liquid crystal-spatial light modulator, and a USB spectrometer. The instrument is capable of simultaneously imaging and acquiring spectra over user defined regions of interest. The microscope can also be operated in a bright-field mode to acquire absorption spectra of micron scale objects. The utility of the instrument is demonstrated on three different samples. First, the instrument is used to resolve three differently labeled fluorescent beads in vitro. Second, the instrument is used to recover time dependent bleaching dynamics that have distinct spectral changes in the cyanobacteria, Synechococcus leopoliensis UTEX 625. Lastly, the technique is used to acquire the absorption spectra of CH3NH3PbBr3 perovskites and measure differences between nanocrystal films and micron scale crystals.

  4. Factors Associated with Immunoglobulin G Subclass Polarization in Naturally Acquired Antibodies to Plasmodium falciparum Merozoite Surface Proteins: a Cross-Sectional Survey in Brazilian Amazonia

    PubMed Central

    Scopel, Kézia K. G.; Fontes, Cor J. F.; Ferreira, Marcelo U.; Braga, Érika M.

    2006-01-01

    We investigated immunoglobulin G (IgG) subclass antibody responses to Plasmodium falciparum merozoite surface protein 1 (MSP-1) and MSP-2 in 112 malaria-exposed subjects in Brazil. IgG3 polarization was primarily epitope driven, being little affected by cumulative or current exposure to malaria and not affected by a subject's age and Fcγ receptor IIA genotype. PMID:16829621

  5. Molecular motion, dielectric response, and phase transition of charge-transfer crystals: acquired dynamic and dielectric properties of polar molecules in crystals.

    PubMed

    Harada, Jun; Ohtani, Masaki; Takahashi, Yukihiro; Inabe, Tamotsu

    2015-04-08

    Molecules in crystals often suffer from severe limitations on their dynamic processes, especially on those involving large structural changes. Crystalline compounds, therefore, usually fail to realize their potential as dielectric materials even when they have large dipole moments. To enable polar molecules to undergo dynamic processes and to provide their crystals with dielectric properties, weakly bound charge-transfer (CT) complex crystals have been exploited as a molecular architecture where the constituent polar molecules have some freedom of dynamic processes, which contribute to the dielectric properties of the crystals. Several CT crystals of polar tetrabromophthalic anhydride (TBPA) molecules were prepared using TBPA as an electron acceptor and aromatic hydrocarbons, such as coronene and perylene, as electron donors. The crystal structures and dielectric properties of the CT crystals as well as the single-component crystal of TBPA were investigated at various temperatures. Molecular reorientation of TBPA molecules did not occur in the single-component crystal, and the crystal did not show a dielectric response due to orientational polarization. We have found that the CT crystal formation provides a simple and versatile method to develop molecular dielectrics, revealing that the molecular dynamics of the TBPA molecules and the dielectric property of their crystals were greatly changed in CT crystals. The TBPA molecules underwent rapid in-plane reorientations in their CT crystals, which exhibited marked dielectric responses arising from the molecular motion. An order-disorder phase transition was observed for one of the CT crystals, which resulted in an abrupt change in the dielectric constant at the transition temperature.

  6. Acquired hyperpigmentations*

    PubMed Central

    Cestari, Tania Ferreira; Dantas, Lia Pinheiro; Boza, Juliana Catucci

    2014-01-01

    Cutaneous hyperpigmentations are frequent complaints, motivating around 8.5% of all dermatological consultations in our country. They can be congenital, with different patterns of inheritance, or acquired in consequence of skin problems, systemic diseases or secondary to environmental factors. The vast majority of them are linked to alterations on the pigment melanin, induced by different mechanisms. This review will focus on the major acquired hyperpigmentations associated with increased melanin, reviewing their mechanisms of action and possible preventive measures. Particularly prominent aspects of diagnosis and therapy will be emphasized, with focus on melasma, post-inflammatory hyperpigmentation, periorbital pigmentation, dermatosis papulosa nigra, phytophotodermatoses, flagellate dermatosis, erythema dyschromicum perstans, cervical poikiloderma (Poikiloderma of Civatte), acanthosis nigricans, cutaneous amyloidosis and reticulated confluent dermatitis PMID:24626644

  7. The impact of absorption coefficient on polarimetric determination of Berry phase based depth resolved characterization of biomedical scattering samples: a polarized Monte Carlo investigation

    SciTech Connect

    Baba, Justin S; Koju, Vijay; John, Dwayne O

    2016-01-01

    The modulation of the state of polarization of photons due to scatter generates associated geometric phase that is being investigated as a means for decreasing the degree of uncertainty in back-projecting the paths traversed by photons detected in backscattered geometry. In our previous work, we established that polarimetrically detected Berry phase correlates with the mean photon penetration depth of the backscattered photons collected for image formation. In this work, we report on the impact of state-of-linear-polarization (SOLP) filtering on both the magnitude and population distributions of image forming detected photons as a function of the absorption coefficient of the scattering sample. The results, based on Berry phase tracking implemented Polarized Monte Carlo Code, indicate that sample absorption plays a significant role in the mean depth attained by the image forming backscattered detected photons.

  8. Polarization-modulation infrared reflection-absorption spectroscopy affording time-resolved simultaneous detection of surface and liquid phase species at catalytic solid-liquid interfaces.

    PubMed

    Meier, Daniel M; Urakawa, Atsushi; Baiker, Alfons

    2009-09-01

    Polarization-modulation infrared reflection-absorption spectroscopy (PM-IRRAS) combined with concentration modulation allows simultaneous monitoring of dynamic evolutions of surface and liquid phase species during reactions at catalytic interfaces as demonstrated for the Pt-catalysed oxidation of CO by O2 in cyclohexane.

  9. The polarization properties of a tilted polarizer.

    PubMed

    Korger, Jan; Kolb, Tobias; Banzer, Peter; Aiello, Andrea; Wittmann, Christoffer; Marquardt, Christoph; Leuchs, Gerd

    2013-11-04

    Polarizers are key components in optical science and technology. Thus, understanding the action of a polarizer beyond oversimplifying approximations is crucial. In this work, we study the interaction of a polarizing interface with an obliquely incident wave experimentally. To this end, a set of Mueller matrices is acquired employing a novel procedure robust against experimental imperfections. We connect our observation to a geometric model, useful to predict the effect of polarizers on complex light fields.

  10. Information Content Analysis for the Multi-Viewing, Multi-Channel, Multi-Polarization Imaging (3MI) Instrument : Toward Retrieval of Vertically Resolved Cloud Properties from Passive Only Measurements.

    NASA Astrophysics Data System (ADS)

    Riedi, J.; Merlin, G.; Labonnote, L.; Cornet, C.; Ferlay, N.; Desmons, M.; Dubuisson, P.; Parol, F.; Davis, A. B.; Marbach, T.

    2014-12-01

    efforts to obtain vertically resolved information on cloud properties from 3MI passive measurements only. In particular the synergy of multiangle polarization measurements at 443 and 865 nm with Oxygen A-band differential absorption information to retrieve cloud geometrical thickness will be discussed.

  11. Theoretical study of dynamic electron-spin-polarization via the doublet-quartet quantum-mixed state and time-resolved ESR spectra of the quartet high-spin state.

    PubMed

    Teki, Yoshio; Matsumoto, Takafumi

    2011-04-07

    The mechanism of the unique dynamic electron polarization of the quartet (S = 3/2) high-spin state via a doublet-quartet quantum-mixed state and detail theoretical calculations of the population transfer are reported. By the photo-induced electron transfer, the quantum-mixed charge-separate state is generated in acceptor-donor-radical triad (A-D-R). This mechanism explains well the unique dynamic electron polarization of the quartet state of A-D-R. The generation of the selectively populated quantum-mixed state and its transfer to the strongly coupled pure quartet and doublet states have been treated both by a perturbation approach and by exact numerical calculations. The analytical solutions show that generation of the quantum-mixed states with the selective populations after de-coherence and/or accompanying the (complete) dephasing during the charge-recombination are essential for the unique dynamic electron polarization. Thus, the elimination of the quantum coherence (loss of the quantum information) is the key process for the population transfer from the quantum-mixed state to the quartet state. The generation of high-field polarization on the strongly coupled quartet state by the charge-recombination process can be explained by a polarization transfer from the quantum-mixed charge-separate state. Typical time-resolved ESR patterns of the quantum-mixed state and of the strongly coupled quartet state are simulated based on the generation mechanism of the dynamic electron polarization. The dependence of the spectral pattern of the quartet high-spin state has been clarified for the fine-structure tensor and the exchange interaction of the quantum-mixed state. The spectral pattern of the quartet state is not sensitive towards the fine-structure tensor of the quantum-mixed state, because this tensor contributes only as a perturbation in the population transfer to the spin-sublevels of the quartet state. Based on the stochastic Liouville equation, it is also

  12. Resolving Two Closely Overlapping -CN Vibrations and Structure in the Langmuir Monolayer of the Long-Chain Nonadecanenitrile by Polarization Sum Frequency Generation Vibrational Spectroscopy

    SciTech Connect

    Zhang, Zhen; Guo, Yuan; Lu, Zhou; Velarde Ruiz Esparza, Luis A.; Wang, Hongfei

    2012-01-10

    Polarization sum frequency generation vibrational spectra (SFG-VS) reveals that there are two distinctively different but closely overlapping -CN vibrations at 2244.5 cm{sup -1} and 2251.1 cm{sup -1}, respectively, in the Langmuir monolayer of the long-chain nonadecanenitrile (C18CN, CH{sub 3}(CH{sub 2}){sub 17}CN, or C18CN)at the air/water interface. The blue shifted -CN groups at 2251.1 cm{sup -1} peak is about 1.8 times broader than that of the 2244.5 cm{sup -1}. Both the spectral shift and spectral width are consistent with the picture that this blue shifted peak corresponds to the solvated -CN group; while the 2244.5 cm{sup -1} peak is the signature of the less solvated -CN group. Polarization dependence of these two peaks further suggest that the -CN group corresponding to the 2251.1 cm{sup -1} peak is tilted with an average angle of 50{sup o} from interface normal, where that to the 2244.5 cm{sup -1} peak is tilted with an angle around 67{sup o}. The relative population for the -CN groups corresponding to the 2251.1 cm{sup -1} peak is about three times of that of the 2244.5 cm{sup -1} peak. These results suggest that the -CN head groups in the C18CN Langmuir monolayer are not aligned uniformly at slightly different depth, in order to avoid the strong repulsive forces between the strong -CN dipoles. The SFG-VS spectra of the O-H stretches at C18CN Langmuir monolayer is similar to those of the 4''-n-pentyl-4-cyano-p-terphenyl (5CT) monolayer, indicating complete exclusion of the water molecules from the C18CN Langmuir monolayer, but significantly different from those of the 4''-n-octyl-4-p-cyanobiphenyl (8CB) monolayer, as well as those of the air/acetonitrile aqueous solution interface. Different from previous held understandings, these results suggest that the structure of the insoluble long-chain C18CN Langmuir monolayer is significantly different from that of the Gibbs adsorption layer of the short chain soluble acetonitrile or propanenitrile aqueous

  13. Energy- and momentum-resolved exchange and spin-orbit interaction in cobalt film by spin-polarized two-electron spectroscopy.

    PubMed

    Samarin, S; Artamonov, O M; Sergeant, A D; Stamps, R; Williams, J F

    2006-09-01

    Spontaneous ordering of electronic spins in ferromagnetic materials is one of the best known and most studied examples of quantum correlations. Exchange correlations are responsible for long range spin order and the spin-orbit interaction (SOI) can create preferred crystalline directions for the spins, i.e., magnetic anisotropy. Presented experimental data illustrate how novel spin-polarized two-electron spectroscopy in-reflection mode allows observation of the localization of spin-dependent interactions in energy-momentum space. Comparison of spin-orbit asymmetries in spectra of Co film and clean W(110) may indicate the presence of interface specific proximity effects providing important clues to the formation of preferred orientations for the magnetic moment of the Co film. These results may help to understand the microscopic origin of interface magnetic anisotropy.

  14. Limiting factors of room-temperature nonradiative photoluminescence lifetime in polar and nonpolar GaN studied by time-resolved photoluminescence and slow positron annihilation techniques

    NASA Astrophysics Data System (ADS)

    Chichibu, S. F.; Uedono, A.; Onuma, T.; Sota, T.; Haskell, B. A.; DenBaars, S. P.; Speck, J. S.; Nakamura, S.

    2005-01-01

    Room-temperature nonradiative lifetime (τnr) of the near-band-edge excitonic photoluminescence (PL) peak in {0001} polar, (112¯0), (11¯00), and (001) nonpolar GaN was shown to increase with the decrease in density or size of Ga vacancies (VGa) and with the decrease in gross density of point defects including complexes, leading to the increase in the PL intensity. As the edge threading dislocation density decreased, density or size of VGa tended to decrease and τnr tended to increase. However, there existed remarkable exceptions. The results indicate that nonradiative recombination process is governed not by single point defects, but by certain defects introduced with the incorporation of VGa, such as VGa-defect complexes.

  15. Primate retina imaging with polarization-sensitive optical coherence tomography

    NASA Astrophysics Data System (ADS)

    Ducros, Mathieu G.; Marsack, Jason D.; Rylander, H. Grady; Thomsen, Sharon L.; Milner, Thomas E.

    2001-12-01

    Polarization-sensitive optical coherence tomography (PSOCT) is applied to determine the depth-resolved polarization state of light backreflected from the eye. The birefringence of the retinal nerve fiber layer (RNFL) was observed and measured from PSOCT images recorded postmortem in a Rhesus monkey. An image-processing algorithm was developed to identify birefringent regions in acquired PSOCT retinal images and automatically determine the thickness of the RNFL. Values of the RNFL thickness determined from histology and PSOCT were compared. PSOCT may provide a new method to determine RNFL thickness and birefringence for glaucoma diagnostics.

  16. Depth-resolved simplified characterization of collagen depletion in dermis with polarization sensitive optical coherence tomography applicable to non-laboratory conditions

    NASA Astrophysics Data System (ADS)

    Tougbaev, Vitali; Eom, Tae Joong; Shin, Woojin; Lee, Yeung Lak; Yu, Bong-Ahn; Kee, Chul-Sik; Ko, Do-Kyeong; Lee, Jongmin

    2007-07-01

    A further insight into the prior concept of polarization sensitive optical coherence tomography system intended for non-laboratory conditions is brought forward and an experimental proof-of-concept is presented. A phenomenological model is adopted from the theory of light depolarization in crystalline polymers and modified to yield a simplified algorithm for mapping depolarization ratio in dermis. The algorithm could distinguish between dermal layers with depleted collagen content and normal dermis of normal perilesional skin. Dermis is simulated by bireringent lamellae of collagen arranged chaotically in multiple layers parallel to the skin surface. Both the design concept and the model imply the sub-millimeter tumor thickness as a proofed prognostic factor and an important criterion for complementary functional diagnostics of skin cancers at their early phase of vertical growth. Choice of the model is inspired by similarity of structural and optical properties between liquid-crystal collagen fibers in dermis and birefringent crystalline lamellae in polymer materials. The numerical computation based on the model allowing for real characteristics of dermis gives plausible interpreting of depolarization peculiarities caused by collagen depletion. Feasibility is discussed of exploiting fiber optic analogs of achromatic retarders. Fabrication of the fiber retarders is shown to be realistic by making use of the photonics technology possessed by the authors.

  17. Mercury's South Polar Region

    NASA Video Gallery

    This animation shows 89 wide-angle camera (WAC) images of Mercury’s south polar region acquired by the Mercury Dual Imaging System (MDIS) over one complete Mercury solar day (176 Earth days). Thi...

  18. Acquired Cystic Kidney Disease

    MedlinePlus

    ... They Work Kidney Disease A-Z Acquired Cystic Kidney Disease What is acquired cystic kidney disease? Acquired cystic kidney disease happens when a ... cysts. What are the differences between acquired cystic kidney disease and polycystic kidney disease? Acquired cystic kidney ...

  19. Resolving Insurgencies

    DTIC Science & Technology

    2011-06-01

    Army, the Department of Defense, or the U.S. Government . Authors of Strategic Studies Institute (SSI) publica- tions enjoy full academic freedom...century, the author identifies four ways in which insurgencies have ended. Clear- cut victories for either the government or the insur- gents occurred...threatened government has resolved the conflict by co-opting the insurgents. After achieving a strategic stalemate and persuading the belligerents that

  20. Acquired reactive perforating collagenosis

    PubMed Central

    Fei, Chengwen; Wang, Yao; Gong, Yu; Xu, Hui; Yu, Qian; Shi, Yuling

    2016-01-01

    Abstract Background: Reactive perforating collagenosis (RPC) is a rare form of transepithelial elimination, in which altered collagen is extruded through the epidermis. There are 2 types of RPC, acquired RPC (ARPC) and inherited RPC, while the latter is extremely rare. Here we report on 1 case of ARPC. Methods: A 73-year-old female was presented with strongly itchy papules over her back and lower limbs for 3 months. She denied the history of oozing or vesiculation. A cutaneous examination showed diffusely distributed multiple well-defined keratotic papules, 4 to 10 mm in diameter, on the bilateral lower limbs and back as well as a few papules on her chest and forearm. Scratching scars were over the resolved lesions while Koebner phenomenon was negative. The patient had a history of type 2 diabetes for 15 years. Laboratory examinations showed elevated blood glucose level. Skin lesion biopsy showed a well-circumscribed area of necrosis filled with a keratotic plug. Parakeratotic cells and lymphocytic infiltration could be seen in the necrosed area. In dermis, sparse fiber bundles were seen perforating the epidermis. These degenerated fiber bundles were notarized as collagen fiber by elastic fiber stain, suggesting a diagnosis of RPC. Results: Then a diagnosis of ARPC was made according to the onset age and the history of diabetes mellitus. She was treated with topical application of corticosteroids twice a day and oral antihistamine once a day along with compound glycyrrhizin tablets 3 times a day. And the blood glucose was controlled in a satisfying range. Two months later, a significant improvement was seen in this patient. Conclusion: Since there is no efficient therapy to RPC, moreover, ARPC is considered to be associated with some systemic diseases, the management of the coexisting disease is quite crucial. The patient in this case received a substantial improvement due to the control of blood glucose and application of compound glycyrrhizin tablets. PMID

  1. THz polarization difference imaging of aqueous targets

    NASA Astrophysics Data System (ADS)

    Sung, Shijun; Bajwa, Neha; Ramirez, Lucia; Grundfest, Warren; Taylor, Zachary

    2015-08-01

    This paper describes the basic design, implementation, and testing of a polarization difference imaging system for use on aqueous targets. The ultimate performance limitation of THz imaging in many active areas of research is clutter from surface geometry. While the signal to nose ratio (SNR) of standard THz imaging systems is quite large, the signal to clutter ratio (SCR) often faced in an imaging application is orders of magnitude lower and, in many cases, lower than the contrast to noise (CNR) resulting in imagery where the contrast mechanism of interest does not significantly contribute to the overall observed contrast. To overcome these limitations we develop a system that uses a circularly polarized source and linearly polarized detectors to acquire images of transverse electric (TE) and transverse magnetic (TM) reflectivities of the target over the same field of view. Geletin based tissue mimicking phantoms are fabricated with spatially varying water content and modified with a range of surface topologies and surface roughness. TE and TM images are combined to yield self-calibrated clutter-suppressed images. The resulting image indicates that the imaging field clutter affected both polarization channels nearly equally allowing the system to resolve differences in phantom water content. This design is a step toward windowless THz imaging capability critical for clinical translation where patient imaging is dominated by clutter.

  2. RESOLVE Project

    NASA Technical Reports Server (NTRS)

    Parker, Ray; Coan, Mary; Cryderman, Kate; Captain, Janine

    2013-01-01

    The RESOLVE project is a lunar prospecting mission whose primary goal is to characterize water and other volatiles in lunar regolith. The Lunar Advanced Volatiles Analysis (LAVA) subsystem is comprised of a fluid subsystem that transports flow to the gas chromatograph - mass spectrometer (GC-MS) instruments that characterize volatiles and the Water Droplet Demonstration (WDD) that will capture and display water condensation in the gas stream. The LAVA Engineering Test Unit (ETU) is undergoing risk reduction testing this summer and fall within a vacuum chamber to understand and characterize component and integrated system performance. Testing of line heaters, printed circuit heaters, pressure transducers, temperature sensors, regulators, and valves in atmospheric and vacuum environments was done. Test procedures were developed to guide experimental tests and test reports to analyze and draw conclusions from the data. In addition, knowledge and experience was gained with preparing a vacuum chamber with fluid and electrical connections. Further testing will include integrated testing of the fluid subsystem with the gas supply system, near-infrared spectrometer, WDD, Sample Delivery System, and GC-MS in the vacuum chamber. This testing will provide hands-on exposure to a flight forward spaceflight subsystem, the processes associated with testing equipment in a vacuum chamber, and experience working in a laboratory setting. Examples of specific analysis conducted include: pneumatic analysis to calculate the WDD's efficiency at extracting water vapor from the gas stream to form condensation; thermal analysis of the conduction and radiation along a line connecting two thermal masses; and proportional-integral-derivative (PID) heater control analysis. Since LAVA is a scientific subsystem, the near-infrared spectrometer and GC-MS instruments will be tested during the ETU testing phase.

  3. RESOLVE Project

    NASA Technical Reports Server (NTRS)

    Parker, Ray O.

    2012-01-01

    The RESOLVE project is a lunar prospecting mission whose primary goal is to characterize water and other volatiles in lunar regolith. The Lunar Advanced Volatiles Analysis (LAVA) subsystem is comprised of a fluid subsystem that transports flow to the gas chromatograph- mass spectrometer (GC-MS) instruments that characterize volatiles and the Water Droplet Demonstration (WDD) that will capture and display water condensation in the gas stream. The LAVA Engineering Test Unit (ETU) is undergoing risk reduction testing this summer and fall within a vacuum chamber to understand and characterize C!Jmponent and integrated system performance. Ray will be assisting with component testing of line heaters, printed circuit heaters, pressure transducers, temperature sensors, regulators, and valves in atmospheric and vacuum environments. He will be developing procedures to guide these tests and test reports to analyze and draw conclusions from the data. In addition, he will gain experience with preparing a vacuum chamber with fluid and electrical connections. Further testing will include integrated testing of the fluid subsystem with the gas supply system, near-infrared spectrometer, WDD, Sample Delivery System, and GC-MS in the vacuum chamber. This testing will provide hands-on exposure to a flight forward spaceflight subsystem, the processes associated with testing equipment in a vacuum chamber, and experience working in a laboratory setting. Examples of specific analysis Ray will conduct include: pneumatic analysis to calculate the WOO's efficiency at extracting water vapor from the gas stream to form condensation; thermal analysis of the conduction and radiation along a line connecting two thermal masses; and proportional-integral-derivative (PID) heater control analysis. In this Research and Technology environment, Ray will be asked to problem solve real-time as issues arise. Since LAVA is a scientific subsystem, Ray will be utilizing his chemical engineering background to

  4. Acquired Idiopathic Generalized Anhidrosis.

    PubMed

    Gangadharan, Geethu; Criton, Sebastian; Surendran, Divya

    2015-01-01

    Acquired idiopathic generalized anhidrosis is a rare condition, where the exact pathomechanism is unknown. We report a case of acquired idiopathic generalized anhidrosis in a patient who later developed lichen planus. Here an autoimmune-mediated destruction of sweat glands may be the probable pathomechanism.

  5. LABORATORY-ACQUIRED MYCOSES

    DTIC Science & Technology

    laboratory- acquired mycoses . Insofar as possible, the etiological fungus, type of laboratory, classification of personnel, type of work conducted, and other...pertinent data have been listed in this study. More than 288 laboratory- acquired mycoses are described here, including 108 cases of

  6. Acquired inflammatory demyelinating neuropathies.

    PubMed

    Ensrud, E R; Krivickas, L S

    2001-05-01

    The acquired demyelinating neuropathies can be divided into those with an acute onset and course and those with a more chronic course. The acute neuropathies present as Guillain-Barré syndrome and include acute inflammatory demyelinating polyradiculoneuropathy (AIDP), Miller Fisher syndrome, acute motor axonal neuropathy (AMAN), acute motor and sensory axonal neuropathy (AMSAN), and acute pandysautonomia. The chronic neuropathies are collectively known as chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) and include MADSAM (multifocal acquired demyelinating sensory and motor neuropathy, also know as Lewis-Sumner syndrome) and DADS (distal acquired demyelinating symmetric neuropathy) as variants. The clinical features, pathology, pathogenesis, diagnosis, treatment, rehabilitation, and prognosis of these neuropathies are discussed.

  7. Multipulse interferometric frequency-resolved optical gating

    SciTech Connect

    Siders, C.W.; Siders, J.L.W.; Omenetto, F.G.; Taylor, A.J.

    1999-04-01

    The authors review multipulse interferometric frequency-resolved optical gating (MI-FROG) as a technique, uniquely suited for pump-probe coherent spectroscopy using amplified visible and near-infrared short-pulse systems and/or emissive targets, for time-resolving ultrafast phase shifts and intensity changes. Application of polarization-gate MI-FROG to the study of ultrafast ionization in gases is presented.

  8. Acquired color vision deficiency.

    PubMed

    Simunovic, Matthew P

    2016-01-01

    Acquired color vision deficiency occurs as the result of ocular, neurologic, or systemic disease. A wide array of conditions may affect color vision, ranging from diseases of the ocular media through to pathology of the visual cortex. Traditionally, acquired color vision deficiency is considered a separate entity from congenital color vision deficiency, although emerging clinical and molecular genetic data would suggest a degree of overlap. We review the pathophysiology of acquired color vision deficiency, the data on its prevalence, theories for the preponderance of acquired S-mechanism (or tritan) deficiency, and discuss tests of color vision. We also briefly review the types of color vision deficiencies encountered in ocular disease, with an emphasis placed on larger or more detailed clinical investigations.

  9. Angle-resolved photoemission with circularly polarized light in the nodal mirror plane of underdoped Bi2Sr2CaCu2O8+δ superconductor

    SciTech Connect

    He, Junfeng; Mion, Thomas R.; Gao, Shang; Myers, Gavin T.; Arita, Masashi; Shimada, Kenya; Gu, G. D.; He, Rui -Hua

    2016-10-31

    Unraveling the nature of pseudogap phase in high-temperature superconductors holds the key to understanding their superconducting mechanisms and potentially broadening their applications via enhancement of their superconducting transition temperatures. Angle-resolved photoemission spectroscopy (ARPES) experiments using circularly polarized light have been proposed to detect possible symmetry breaking state in the pseudogap phase of cuprates. Here, the presence (absence) of an electronic order which breaks mirror symmetry of the crystal would in principle induce a finite (zero) circular dichroism in photoemission. Different orders breaking reflection symmetries about different mirror planes can also be distinguished by the momentum dependence of the measured circular dichroism.

  10. Clustering of polarization-encoded images.

    PubMed

    Zallat, Jihad; Collet, Christophe; Takakura, Yoshitate

    2004-01-10

    Polarization-encoded imaging consists of the distributed measurements of polarization parameters for each pixel of an image. We address clustering of multidimensional polarization-encoded images. The spatial coherence of polarization information is considered. Two methods of analysis are proposed: polarization contrast enhancement and a more-sophisticated image-processing algorithm based on a Markovian model. The proposed algorithms are applied and validated with two different Mueller images acquired by a fully polarimetric imaging system.

  11. Time-Resolved Hard X-Ray Spectrometer

    SciTech Connect

    Kenneth Moya; Ian McKennaa; Thomas Keenana; Michael Cuneob

    2007-03-01

    Wired array studies are being conducted at the SNL Z accelerator to maximize the x-ray generation for inertial confinement fusion targets and high energy density physics experiments. An integral component of these studies is the characterization of the time-resolved spectral content of the x-rays. Due to potential spatial anisotropy in the emitted radiation, it is also critical to diagnose the time-evolved spectral content in a space-resolved manner. To accomplish these two measurement goals, we developed an x-ray spectrometer using a set of high-speed detectors (silicon PIN diodes) with a collimated field-of-view that converged on a 1-cm-diameter spot at the pinch axis. Spectral discrimination is achieved by placing high Z absorbers in front of these detectors. We built two spectrometers to permit simultaneous different angular views of the emitted radiation. Spectral data have been acquired from recent Z shots for the radial and polar views. UNSPEC1 has been adapted to analyze and unfold the measured data to reconstruct the x-ray spectrum. The unfold operator code, UFO2, is being adapted for a more comprehensive spectral unfolding treatment.

  12. Time-resolved hard x-ray spectrometer

    NASA Astrophysics Data System (ADS)

    Moy, Kenneth; Cuneo, Michael; McKenna, Ian; Keenan, Thomas; Sanford, Thomas; Mock, Ray

    2006-08-01

    Wired array studies are being conducted at the SNL Z accelerator to maximize the x-ray generation for inertial confinement fusion targets and high energy density physics experiments. An integral component of these studies is the characterization of the time-resolved spectral content of the x-rays. Due to potential spatial anisotropy in the emitted radiation, it is also critical to diagnose the time-evolved spectral content in a space-resolved manner. To accomplish these two measurement goals, we developed an x-ray spectrometer using a set of high-speed detectors (silicon PIN diodes) with a collimated field-of-view that converged on a 1-cm-diameter spot at the pinch axis. Spectral discrimination is achieved by placing high Z absorbers in front of these detectors. We built two spectrometers to permit simultaneous different angular views of the emitted radiation. Spectral data have been acquired from recent Z shots for the radial and axial (polar) views. UNSPEC 1 has been adapted to analyze and unfold the measured data to reconstruct the x-ray spectrum. The unfold operator code, UFO2, is being adapted for a more comprehensive spectral unfolding treatment.

  13. Polarized cells, polar actions.

    PubMed

    Maddock, J R; Alley, M R; Shapiro, L

    1993-11-01

    The recognition of polar bacterial organization is just emerging. The examples of polar localization given here are from a variety of bacterial species and concern a disparate array of cellular functions. A number of well-characterized instances of polar localization of bacterial proteins, including the chemoreceptor complex in both C. crescentus and E. coli, the maltose-binding protein in E. coli, the B. japonicum surface attachment proteins, and the actin tail of L. monocytogenes within a mammalian cell, involve proteins or protein complexes that facilitate bacterial interaction with the environment, either the extracellular milieux or that within a plant or mammalian host. The significance of this observation remains unclear. Polarity in bacteria poses many problems, including the necessity for a mechanism for asymmetrically distributing proteins as well as a mechanism by which polar localization is maintained. Large structures, such as a flagellum, are anchored at the pole by means of the basal body that traverses the peptidoglycan wall. But for proteins and small complexes, whether in the periplasm or the membrane, one must invoke a mechanism that prevents the diffusion of these proteins away from the cell pole. Perhaps the periplasmic proteins are retained at the pole by the presence of the periseptal annulus (35). The constraining features for membrane components are not known. For large aggregates, such as the clusters of MCP, CheA, and CheW complexes, perhaps the size of the aggregate alone prevents displacement. In most cases of cellular asymmetry, bacteria are able to discriminate between the new pole and the old pole and to utilize this information for localization specificity. The maturation of new pole to old pole appears to be a common theme as well. Given numerous examples reported thus far, we propose that bacterial polarity displays specific rules and is a more general phenomenon than has been previously recognized.

  14. Generalized mosaicing: polarization panorama.

    PubMed

    Schechner, Yoav Y; Nayar, Shree K

    2005-04-01

    We present an approach to image the polarization state of object points in a wide field of view, while enhancing the radiometric dynamic range of maging systems by generalizing image mosaicing. The approach is biologically-inspired, as it emulates spatially varying polarization sensitivity of some animals. In our method, a spatially varying polarization and attenuation filter is rigidly attached to a camera. As the system moves, it senses each scene point multiple times, each time filtering it through a different filter polarizing angle, polarizance, and transmittance. Polarization is an additional dimension of the generalized mosaicing paradigm, which has recently yielded high dynamic range images and multispectral images in a wide field of view using other kinds of filters. The image acquisition is as easy as in traditional image mosaics. The computational algorithm can easily handle nonideal polarization filters (partial polarizers), variable exposures, and saturation in a single framework. The resulting mosaic represents the polarization state at each scene point. Using data acquired by this method, we demonstrate attenuation and enhancement of specular reflections and semireflection separation in an image mosaic.

  15. Acquired hypofibrinogenemia: current perspectives

    PubMed Central

    Besser, Martin W; MacDonald, Stephen G

    2016-01-01

    Acquired hypofibrinogenemia is most frequently caused by hemodilution and consumption of clotting factors. The aggressive replacement of fibrinogen has become one of the core principles of modern management of massive hemorrhage. The best method for determining the patient’s fibrinogen level remains controversial, and particularly in acquired dysfibrinogenemia, could have major therapeutic implications depending on which quantification method is chosen. This review introduces the available laboratory and point-of-care methods and discusses the relative advantages and limitations. It also discusses current strategies for the correction of hypofibrinogenemia. PMID:27713652

  16. Community-acquired pneumonia.

    PubMed

    Falguera, M; Ramírez, M F

    2015-11-01

    This article not only reviews the essential aspects of community-acquired pneumonia for daily clinical practice, but also highlights the controversial issues and provides the newest available information. Community-acquired pneumonia is considered in a broad sense, without excluding certain variants that, in recent years, a number of authors have managed to delineate, such as healthcare-associated pneumonia. The latter form is nothing more than the same disease that affects more frail patients, with a greater number of risk factors, both sharing an overall common approach.

  17. Transmission of polarized light in skeletal muscle

    NASA Astrophysics Data System (ADS)

    Shuaib, Ali; Li, Xin; Yao, Gang

    2011-02-01

    Experiments were conducted to study polarized light transmission in fresh bovine skeletal muscle of varying thicknesses. Two-dimensional polarization-sensitive transmission images were acquired and analyzed using a numerical parametric fitting algorithm. The total transmittance intensity and degree-of-polarization were calculated for both central ballistic and surrounding scattering regions. Full Mueller matrix images were derived from the raw polarization images and the polar decomposition algorithm was applied to extract polarization parameters. The results suggest that polarized light propagation through skeletal muscle is affected by strong birefringence, diattenuation, multiple scattering induced depolarization and the sarcomere diffraction effect.

  18. IFM-Modeled Response of the High-Latitude Ionosphere to Auroral Dynamics Based on Auroral Observations Acquired with the Visible Imaging System(VIS) on the Polar Spacecraft

    NASA Astrophysics Data System (ADS)

    Bekerat, H.; Sigwarth, J.; Schunk, R.; Eccles, V.

    2007-12-01

    Global physics-based models for the high-latitude ionosphere have been developed to such an extent that the large and small ionospheric features during magnetic storms and substorms can be studied. These models, however, require inputs for the magnetospheric forcing, i.e. Magnetospheric convection and particle precipitation. More specifically, for these models to yield reliable results during magnetic storms and substorms, reliable global maps for the high-latitude magnetospheric convection and auroral electron particle precipitation patterns as a function of time are needed. Over the last decades several statistical models for the high-latitude convection and particle precipitation have been developed and used to drive ionospheric models. However, due to the statistical nature of these models, they represent the average characteristics of the true convection and precipitation patten and they are very limited to simulate the effect of magnetic storms and substorms. Recently, with the realization of the Visible Imaging System (VIS) on the Polar Spacecraft, auroral images that yield information of auroral dynamics on a global scale with a spatial resolution of less than 100 km and temporal resolution of ~ 1 minute have become available. These images can be used to calculate reliable global maps for the particle precipitation parameters, electron energy flux and average energies, as a function of time. In this poster we present the preliminary results of our attempt to drive the Ionosphere Forecast Model (IFM) using global maps for the electron precipitation parameters calculated from the corresponding VIS images. In order to elucidate the effect of auroral dynamics on the high-latitude ionosphere, a one-day data set of VIS images during which the aurora was highly active is selected for this study. Then, these images are used to calculate global maps for the electron precipitation parameters using the Lumerzheim model. Next, the maps obtained in the previous step are

  19. Acquired Brain Injury Program.

    ERIC Educational Resources Information Center

    Schwartz, Stacey Hunter

    This paper reviews the Acquired Brain Injury (ABI) Program at Coastline Community College (California). The ABI Program is a two-year, for-credit educational curriculum designed to provide structured cognitive retraining for adults who have sustained an ABI due to traumatic (such as motor vehicle accident or fall) or non-traumatic(such as…

  20. Polarization measurement through combination polarizers

    NASA Astrophysics Data System (ADS)

    Bai, Yunfeng; Li, Linjun; He, Zhelong; Liu, Yanwei; Ma, Cheng; Shi, Guang; Liu, Lu

    2014-02-01

    Polarization measurement approaches only using polarizer and grating is present. The combination polarizers consists of two polarizers: one is γ degree with the X axis; the other is along the Y axis. Binary grating is covered by the combination polarizers, and based on Fraunhofer diffraction, the diffraction intensity formula is deduced. The polarization state of incident light can be gotten by fitting the diffraction pattern with the deduced formula. Compared with the traditional polarization measurement method, this measurement only uses polarizer and grating, therefore, it can be applied to measure a wide wavelength range without replacing device in theory.

  1. 43 CFR 3837.30 - Disputes about acquiring a delinquent co-claimant's interests.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 43 Public Lands: Interior 2 2014-10-01 2014-10-01 false Disputes about acquiring a delinquent co... DELINQUENT CO-CLAIMANT'S INTERESTS IN A MINING CLAIM OR SITE Resolving Co-Claimant Disputes About Acquiring a Delinquent Co-Claimant's Interests § 3837.30 Disputes about acquiring a delinquent co-claimant's...

  2. 43 CFR 3837.30 - Disputes about acquiring a delinquent co-claimant's interests.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 43 Public Lands: Interior 2 2011-10-01 2011-10-01 false Disputes about acquiring a delinquent co... DELINQUENT CO-CLAIMANT'S INTERESTS IN A MINING CLAIM OR SITE Resolving Co-Claimant Disputes About Acquiring a Delinquent Co-Claimant's Interests § 3837.30 Disputes about acquiring a delinquent co-claimant's...

  3. 43 CFR 3837.30 - Disputes about acquiring a delinquent co-claimant's interests.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 43 Public Lands: Interior 2 2013-10-01 2013-10-01 false Disputes about acquiring a delinquent co... DELINQUENT CO-CLAIMANT'S INTERESTS IN A MINING CLAIM OR SITE Resolving Co-Claimant Disputes About Acquiring a Delinquent Co-Claimant's Interests § 3837.30 Disputes about acquiring a delinquent co-claimant's...

  4. 43 CFR 3837.30 - Disputes about acquiring a delinquent co-claimant's interests.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 43 Public Lands: Interior 2 2012-10-01 2012-10-01 false Disputes about acquiring a delinquent co... DELINQUENT CO-CLAIMANT'S INTERESTS IN A MINING CLAIM OR SITE Resolving Co-Claimant Disputes About Acquiring a Delinquent Co-Claimant's Interests § 3837.30 Disputes about acquiring a delinquent co-claimant's...

  5. Dark Polar Dunes

    NASA Technical Reports Server (NTRS)

    2005-01-01

    20 January 2004 This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image, acquired during northern summer in December 2004, shows dark, windblown sand dunes in the north polar region of Mars. A vast sea of sand dunes nearly surrounds the north polar cap. These landforms are located near 80.3oN, 144.1oW. Light-toned features in the image are exposures of the substrate that underlies the dune field. The image covers an area about 3 km (1.9 mi) wide and is illuminated by sunlight from the lower left.

  6. Hospital-acquired thrombocytopenia.

    PubMed

    McMahon, Christine M; Cuker, Adam

    2014-10-01

    The development of thrombocytopenia is common in hospitalized patients and is associated with increased mortality. Frequent and important causes of thrombocytopenia in hospitalized patients include etiologies related to the underlying illness for which the patient is admitted, such as infection and disseminated intravascular coagulation, and iatrogenic etiologies such as drug-induced immune thrombocytopenia, heparin-induced thrombocytopenia, posttransfusion purpura, hemodilution, major surgery, and extracorporeal circuitry. This review presents a brief discussion of the pathophysiology, distinguishing clinical features, and management of these etiologies, and provides a diagnostic approach to hospital-acquired thrombocytopenia that considers the timing and severity of the platelet count fall, the presence of hemorrhage or thrombosis, the clinical context, and the peripheral blood smear. This approach may offer guidance to clinicians in distinguishing among the various causes of hospital-acquired thrombocytopenia and providing management appropriate to the etiology.

  7. Desmosomes in acquired disease

    PubMed Central

    Stahley, Sara N.; Kowalczyk, Andrew P.

    2015-01-01

    Desmosomes are cell-cell junctions that mediate adhesion and couple the intermediate filament cytoskeleton to sites of cell-cell contact. This architectural arrangement functions to integrate adhesion and cytoskeletal elements of adjacent cells. The importance of this robust adhesion system is evident in numerous human diseases, both inherited and acquired, that occur when desmosome function is compromised. This review focuses on autoimmune and infectious diseases that impair desmosome function. In addition, we discuss emerging evidence that desmosomal genes are often misregulated in cancer. The emphasis of our discussion is placed on how human diseases inform our understanding of basic desmosome biology, and in turn, how fundamental advances in the cell biology of desmosomes may lead to new treatments for acquired diseases of the desmosome. PMID:25795143

  8. Desmosomes in acquired disease.

    PubMed

    Stahley, Sara N; Kowalczyk, Andrew P

    2015-06-01

    Desmosomes are cell-cell junctions that mediate adhesion and couple the intermediate filament cytoskeleton to sites of cell-cell contact. This architectural arrangement integrates adhesion and cytoskeletal elements of adjacent cells. The importance of this robust adhesion system is evident in numerous human diseases, both inherited and acquired, which occur when desmosome function is compromised. This review focuses on autoimmune and infectious diseases that impair desmosome function. In addition, we discuss emerging evidence that desmosomal genes are often misregulated in cancer. The emphasis of our discussion is placed on the way in which human diseases can inform our understanding of basic desmosome biology and in turn, the means by which fundamental advances in the cell biology of desmosomes might lead to new treatments for acquired diseases of the desmosome.

  9. Forward Monte Carlo Computations of Polarized Microwave Radiation

    NASA Technical Reports Server (NTRS)

    Battaglia, A.; Kummerow, C.

    2000-01-01

    Microwave radiative transfer computations continue to acquire greater importance as the emphasis in remote sensing shifts towards the understanding of microphysical properties of clouds and with these to better understand the non linear relation between rainfall rates and satellite-observed radiance. A first step toward realistic radiative simulations has been the introduction of techniques capable of treating 3-dimensional geometry being generated by ever more sophisticated cloud resolving models. To date, a series of numerical codes have been developed to treat spherical and randomly oriented axisymmetric particles. Backward and backward-forward Monte Carlo methods are, indeed, efficient in this field. These methods, however, cannot deal properly with oriented particles, which seem to play an important role in polarization signatures over stratiform precipitation. Moreover, beyond the polarization channel, the next generation of fully polarimetric radiometers challenges us to better understand the behavior of the last two Stokes parameters as well. In order to solve the vector radiative transfer equation, one-dimensional numerical models have been developed, These codes, unfortunately, consider the atmosphere as horizontally homogeneous with horizontally infinite plane parallel layers. The next development step for microwave radiative transfer codes must be fully polarized 3-D methods. Recently a 3-D polarized radiative transfer model based on the discrete ordinate method was presented. A forward MC code was developed that treats oriented nonspherical hydrometeors, but only for plane-parallel situations.

  10. Time-Resolved Imaging of the Phase Transition in the Melt-Grown Spherulites of Isotactic Polybutene-1 as Detected by the Two-Dimensional Polarized IR Imaging Technique.

    PubMed

    Hu, Jian; Tashiro, Kohji

    2016-05-26

    In order to visualize the 2D spatial distribution of the structural change in the phase transition from crystal form II to I of isotactic polybutene-1 spherulite grown from the melt, the time-dependent measurement of the 2D polarized FTIR spectra has been performed. At a melt-isothermal crystallization temperature of 103 °C, the square-shape spherulite appeared from the melt and grew with time. When the isothermal crystallization occurred at 98 °C, the round-shaped spherulite was observed. In both cases, after the temperature jump to an ambient temperature, the 2D images changed clearly in the process of the phase transition from form II to form I, but the spherulite morphology itself was not changed detectably. The polarized IR imaging has revealed the preferential orientation of the crystallites in the spherulite. In the case of the spherulite grown at 103 °C, the ab plane is oriented in parallel to the spherulite plane and the molecular chains stand along the normal to the surface. On the other hand, in the spherulite grown at 98 °C, the chains were found to lie on the spherulite plane preferentially. Such a difference in the crystal orientation in the spherulite is related intimately with the outer shape of the spherulite and also with the growth mechanism of the spherulite. In this way, the polarized 2D IR imaging was found to be quite useful for the in situ detection of the time-dependently changing 2D spatial distribution of the crystallites in the spherulite.

  11. Polarization Imager Technology. Phase I

    DTIC Science & Technology

    2007-11-02

    orientation axes (e.g., with a polarizing filter). Resolving image irradiance at three (3) unique orientations is sufficient for unique measurement. Using...an orientation reference and resolving the electric field at relative 0’, 450, 900, if the image irradiances obtained at each pixel are respectively...with the video rate of the camera. See Figure 2. The unpolarized component is not effected . Each TN liquid crystal is binary in the sense that it either

  12. Acquired Factor V Inhibitor

    PubMed Central

    Hirai, Daisuke; Yamashita, Yugo; Masunaga, Nobutoyo; Katsura, Toshiaki; Akao, Masaharu; Okuno, Yoshiaki; Koyama, Hiroshi

    2016-01-01

    Inhibitors directed against factor V rarely occur, and the clinical symptoms vary. We herein report the case of a patient who presented with a decreased factor V activity that had decreased to <3 %. We administered vitamin K and 6 units of fresh frozen plasma, but she thereafter developed an intracerebral hemorrhage. It is unclear whether surgery >10 years earlier might have caused the development of a factor V inhibitor. The treatment of acquired factor V inhibitors is mainly the transfusion of platelet concentrates and corticosteroids. Both early detection and the early initiation of the treatment of factor V inhibitor are thus considered to be important. PMID:27746446

  13. Polarization Imaging Apparatus

    NASA Technical Reports Server (NTRS)

    Zou, Yingyin K.; Chen, Qiushui

    2010-01-01

    A polarization imaging apparatus has shown promise as a prototype of instruments for medical imaging with contrast greater than that achievable by use of non-polarized light. The underlying principles of design and operation are derived from observations that light interacts with tissue ultrastructures that affect reflectance, scattering, absorption, and polarization of light. The apparatus utilizes high-speed electro-optical components for generating light properties and acquiring polarization images through aligned polarizers. These components include phase retarders made of OptoCeramic (registered TradeMark) material - a ceramic that has a high electro-optical coefficient. The apparatus includes a computer running a program that implements a novel algorithm for controlling the phase retarders, capturing image data, and computing the Stokes polarization images. Potential applications include imaging of superficial cancers and other skin lesions, early detection of diseased cells, and microscopic analysis of tissues. The high imaging speed of this apparatus could be beneficial for observing live cells or tissues, and could enable rapid identification of moving targets in astronomy and national defense. The apparatus could also be used as an analysis tool in material research and industrial processing.

  14. [Acquired coagulant factor inhibitors].

    PubMed

    Nogami, Keiji

    2015-02-01

    Acquired coagulation factor inhibitors are an autoimmune disease causing bleeding symptoms due to decreases in the corresponding factor (s) which result from the appearance of autoantibodies against coagulation factors (inhibitor). This disease is quite different from congenital coagulation factor deficiencies based on genetic abnormalities. In recent years, cases with this disease have been increasing, and most have anti-factor VIII autoantibodies. The breakdown of the immune control mechanism is speculated to cause this disease since it is common in the elderly, but the pathology and pathogenesis are presently unclear. We herein describe the pathology and pathogenesis of factor VIII and factor V inhibitors. Characterization of these inhibitors leads to further analysis of the coagulation process and the activation mechanisms of clotting factors. In the future, with the development of new clotting examination method (s), we anticipate that further novel findings will be obtained in this field through inhibitor analysis. In addition, detailed elucidation of the coagulation inhibitory mechanism possibly leading to hemostatic treatment strategies for acquired coagulation factor disorders will be developed.

  15. Polarization Effects in Optical Coherence Tomography of Various Biological Tissues

    PubMed Central

    de Boer, Johannes F.; Srinivas, Shyam M.; Park, B. Hyle; Pham, Tuan H.; Chen, Zhongping; Milner, Thomas E.; Nelson, J. Stuart

    2015-01-01

    Polarization sensitive optical coherence tomography (PS-OCT) was used to obtain spatially resolved ex vivo images of polarization changes in skeletal muscle, bone, skin and brain. Through coherent detection of two orthogonal polarization states of the signal formed by interference of light reflected from the biological sample and a mirror in the reference arm of a Michelson interferometer, the depth resolved change in polarization was measured. Inasmuch as any fibrous structure will influence the polarization of light, PS-OCT is a potentially powerful technique investigating tissue structural properties. In addition, the effects of single polarization state detection on OCT image formation is demonstrated. PMID:25774083

  16. Acquired epidermodysplasia verruciformis.

    PubMed

    Rogers, Heather D; Macgregor, Jennifer L; Nord, Kristin M; Tyring, Stephen; Rady, Peter; Engler, Danielle E; Grossman, Marc E

    2009-02-01

    Epidermodysplasia verruciformis (EV) is a rare autosomal recessive genodermatosis with an increased susceptibility to specific human papillomavirus (HPV) genotypes. Classically, this viral infection leads to the development of tinea versicolor-like macules on the trunk, neck, arms, and face during childhood, and over time, these lesions can progress to squamous cell carcinoma. More recently, an EV-like syndrome has been described in patients with impaired cell-mediated immunity. We describe two cases of EV-like syndrome in HIV-positive patients, review all previously reported cases of EV in patients with impaired cell-mediated immunity, introduce the term "acquired epidermodysplasia verruciformis" to describe EV developing in the immunocompromised host and examine the limited treatment options for these patients.

  17. AIDS: acquired immunodeficiency syndrome.

    PubMed Central

    Gilmore, N. J.; Beaulieu, R.; Steben, M.; Laverdière, M.

    1983-01-01

    Acquired immunodeficiency syndrome, or AIDS, is a new illness that occurs in previously healthy individuals. It is characterized by immunodeficiency, opportunistic infections and unusual malignant diseases. Life-threatening single or multiple infections with viruses, mycobacteria, fungi or protozoa are common. A rare neoplasm, Kaposi's sarcoma, has developed in approximately one third of patients with AIDS. More than 800 cases of AIDS have been reported in North America, over 24 of them in Canada. The majority of patients are male homosexuals, although AIDS has also developed in abusers of intravenously administered drugs, Haitian immigrants, individuals with hemophilia, recipients of blood transfusions, prostitutes, and infants, spouses and partners of patients with AIDS. The cause of AIDS is unknown, but the features are consistent with an infectious process. Early diagnosis can be difficult owing to the nonspecific symptoms and signs of the infections and malignant diseases. Therefore, vigilance by physicians is of utmost importance. PMID:6342737

  18. AIDS: acquired immunodeficiency syndrome *

    PubMed Central

    Gilmore, N.J.; Beaulieu, R.; Steben, M.; Laverdière, M.

    1992-01-01

    Acquired immunodeficiency syndrome, or AIDS, is a new illness that occurs in previously healthy individuals. It is characterized by immunodeficiency, opportunistic infections and unusual malignant diseases. Life-threatening single or multiple infections with viruses, mycobacteria, fungi or protozoa are common. A rare neoplasm, Kaposi's sarcoma, has developed in approximately one third of patients with AIDS. More than 800 cases of AIDS have been reported in North America, over 24 of them in Canada. The majority of patients are male homosexuals, although AIDS has also developed in abusers of intravenously administered drugs, Haitian immigrants, individuals with hemophilia, recipients of blood transfusions, prostitutes, and infants, spouses and partners of patients with AIDS. The cause of AIDS is unknown, but the features are consistent with an infectious process. Early diagnosis can be difficult owing to the nonspecific symptoms and signs of the infections and malignant diseases. Therefore, vigilance by physicians is of the utmost importance. PMID:1544049

  19. SCATTERING POLARIZATION IN SOLAR FLARES

    SciTech Connect

    Štěpán, Jiří; Heinzel, Petr

    2013-11-20

    There is ongoing debate about the origin and even the very existence of a high degree of linear polarization of some chromospheric spectral lines observed in solar flares. The standard explanation of these measurements is in terms of the impact polarization caused by non-thermal proton and/or electron beams. In this work, we study the possible role of resonance line polarization due to radiation anisotropy in the inhomogeneous medium of the flare ribbons. We consider a simple two-dimensional model of the flaring chromosphere and we self-consistently solve the non-LTE problem taking into account the role of resonant scattering polarization and of the Hanle effect. Our calculations show that the horizontal plasma inhomogeneities at the boundary of the flare ribbons can lead to a significant radiation anisotropy in the line formation region and, consequently, to a fractional linear polarization of the emergent radiation of the order of several percent. Neglecting the effects of impact polarization, our model can provide a clue for resolving some of the common observational findings, namely: (1) why a high degree of polarization appears mainly at the edges of the flare ribbons; (2) why polarization can also be observed during the gradual phase of a flare; and (3) why polarization is mostly radial or tangential. We conclude that radiation transfer in realistic multi-dimensional models of solar flares needs to be considered as an essential ingredient for understanding the observed spectral line polarization.

  20. A new movable polarized target at Dubna

    NASA Astrophysics Data System (ADS)

    Anischenko, N. G.; Bazhanov, N. A.; Benda, B.; Borisov, N. S.; Borzunov, Yu. T.; Burinov, V. F.; Durand, G.; Dzyubak, A. P.; Gevchuk, A. V.; Golovanov, L. B.; Gurevich, G. M.; Kovalev, A. I.; Lazarev, A. B.; Leconte, Ph.; Lehar, F.; de Lesquen, A.; Lukhanin, A. A.; Matafonov, V. N.; Matyushevsky, E. A.; Mironov, S.; Neganov, A. B.; Piskunov, N. M.; Plis, Yu. A.; Shilov, S. N.; Shishov, Yu. A.; Sorokin, P. V.; Teterin, V. V.; Topalov, S.; Trautman, V. Yu.; Tsvinev, A. P.; Usov, Yu. A.

    1995-09-01

    A description of the recently installed mouable Polarized Proton Targe (MPT) at the JINR in Dubna is described. This target was acquired from Fermilab. The physics program based on the MPT at Dbna is outlined. (AIP)

  1. Fast frequency-resolved terahertz imaging

    NASA Astrophysics Data System (ADS)

    Yasuda, Takashi; Kawada, Yoichi; Toyoda, Haruyoshi; Nakanishi, Atsushi; Akiyama, Koichiro; Takahashi, Hironori

    2011-03-01

    We propose a fast, frequency-resolved, real-time, terahertz imaging method. With our method, images at two specific terahertz frequencies can be acquired in 1 min. Three kinds of drugs (L-histidine, maltose, and CBZ3), which have absorption peaks in the terahertz region, were distinguished in 3 min by using our method. This technique can be used in industrial applications, such as nondestructive testing.

  2. Characterization of Ultrafast Laser Pulses using a Low-dispersion Frequency Resolved Optical Grating Spectrometer

    NASA Astrophysics Data System (ADS)

    Whitelock, Hope; Bishop, Michael; Khosravi, Soroush; Obaid, Razib; Berrah, Nora

    2016-05-01

    A low dispersion frequency-resolved optical gating (FROG) spectrometer was designed to characterize ultrashort (<50 femtosecond) laser pulses from a commercial regenerative amplifier, optical parametric amplifier, and a home-built non-colinear optical parametric amplifier. This instrument splits a laser pulse into two replicas with a 90:10 intensity ratio using a thin pellicle beam-splitter and then recombines the pulses in a birefringent medium. The instrument detects a wavelength-sensitive change in polarization of the weak probe pulse in the presence of the stronger pump pulse inside the birefringent medium. Scanning the time delay between the two pulses and acquiring spectra allows for characterization of the frequency and time content of ultrafast laser pulses, that is needed for interpretation of experimental results obtained from these ultrafast laser systems. Funded by the DoE-BES, Grant No. DE-SC0012376.

  3. Resolving the Pericenter

    NASA Astrophysics Data System (ADS)

    Wisdom, Jack

    2015-10-01

    The Wisdom-Holman mapping method and its variations have become a mainstay of research in solar system dynamics. But the method is not without its limitations. Rauch & Holman noted that at large eccentricities sufficiently small steps must be taken to resolve the pericenter. In this paper, I explore in more detail what it means to resolve the pericenter.

  4. Angle-resolved optical coherence tomography

    NASA Astrophysics Data System (ADS)

    Desjardins, Adrien Emmanuel

    Optical coherence tomography (OCT) has emerged as a powerful tool for probing the microstructure of biological tissue non-invasively at high-speed. OCT measures depth-resolved reflectance of infrared light, generating cross-sectional images non-invasively with micron-scale resolution. As with other imaging modalities that employ coherent detection, OCT images are confounded by speckle noise. Speckle imposes a grainy texture on images that reduces the signal-to-noise ratio to near unity values. As a result, it conceals subtle differences in scattering properties known to be crucial for differentiating normal from diseased tissue states. In this thesis, we developed a novel OCT modality called "Angle-Resolved OCT" in which depth scans (A-lines) are obtained simultaneously from a broad range of backscattering angles. We demonstrated that high levels of speckle reduction can be achieved by averaging the magnitudes of A-lines corresponding to the same transverse locations. With both experimental and analytic approaches, we demonstrated that this averaging method does not lead to a substantial loss in spatial resolution. We developed two different imaging systems for performing Angle-Resolved OCT. With the first system, angular data was acquired simultaneously; with the second, it was acquired sequentially. The first system had superior speckle-reduction capabilities but image quality degraded significantly with small sample movements. The second system allowed for in vivo imaging, as demonstrated with Resolved OCT systems, the speckle-reduced images showed hitherto unprecedented delineation of tissue microstructure.

  5. The interfacial and surface properties of thin Fe and Gd films grown on W(110) as studied by scanning tunneling microscopy, site-resolved photoelectron diffraction, and spin polarized photoelectron diffraction

    SciTech Connect

    Tober, Eric D.

    1997-06-01

    Combined scanning tunneling microscopy (STM) and low energy electron diffraction (LEED) measurements from Gd films grown on W(110) prepared with and without annealing have been used to provide a detailed picture of the growth of such films, permitting a quantitative structural explanation for previously-measured magnetic properties and the identification of a new two-dimensional structure for the first monolayer. The analysis of the film roughness of room-temperature-grown films as a function of coverage and lateral length scale reveals that the growing Gd surface follows scaling laws for a self-affine surface. Annealing these as-deposited films at elevated temperatures is found to drastically alter the morphology of the films, as seen by both STM and LEED. Nanometer-scale islands of relatively well-defined size and shape are observed under certain conditions. Finally, the first monolayer of Gd is observed to form a (7x14) superstructure with pseudo-(7x7) symmetry that is consistent with a minimally-distorted hexagonal two-dimensional Gd(0001) film. Furthermore, a new beamline and photoelectron spectrometer/diffractometer at the Advanced Light Source have been used to obtain full-solid-angle and site-specific photoelectron diffraction (PD) data from interface W atoms just beneath (1x1) Fe and (7x14) Gd monolayers on W(110) by utilizing the core level shift in the W 4f7/2 spectrum. A comparison of experiment with multiple scattering calculations permits determining the Fe adsorption site and the relative interlayer spacing to the first and second W layers. These Fe results are also compared to those from the very different Gd overlayer and from the clean W(110) surface. Such interface PD measurements show considerable promise for future studies. Finally, the rare-earth ferromagnetic system of Gd(0001) has been examined through the use of spin polarized photoelectron diffraction from the Gd 4s and 5s photoelectron multiplets.

  6. Acquired aplastic anemia.

    PubMed

    Keohane, Elaine M

    2004-01-01

    Acquired aplastic anemia (AA) is a disorder characterized by a profound deficit of hematopoietic stem and progenitor cells, bone marrow hypocellularity, and peripheral blood pancytopenia. It primarily affects children, young adults, and those over 60 years of age. The majority of cases are idiopathic; however, idiosyncratic reactions to some drugs, chemicals, and viruses have been implicated in its etiology. An autoimmune T-cell reaction likely causes the stem cell depletion, but the precise mechanism, as well as the eliciting and target antigens, is unknown. Symptoms vary from severe life-threatening cytopenias to moderate or non-severe disease that does not require transfusion support. The peripheral blood typically exhibits pancytopenia, reticulocytopenia, and normocytic or macrocytic erythrocytes. The bone marrow is hypocellular and may exhibit dysplasia of the erythrocyte precursors. First line treatment for severe AA consists of hematopoietic stem cell transplantation in young patients with HLA identical siblings, while immunosuppression therapy is used for older patients and for those of any age who lack a HLA matched donor. Patients with AA have an increased risk of developing paroxysmal nocturnal hemoglobinuria (PNH), myelodysplastic syndrome (MDS), or acute leukemia. Further elucidation of the pathophysiology of this disease will result in a better understanding of the interrelationship among AA, PNH, and MDS, and may lead to novel targeted therapies.

  7. Acquired spatial dyslexia.

    PubMed

    Siéroff, E

    2015-08-10

    Acquired spatial dyslexia is a reading disorder frequently occurring after left or right posterior brain lesions. This article describes several types of spatial dyslexia with an attentional approach. After right posterior lesions, patients show left neglect dyslexia with errors on the left side of text, words, and non-words. The deficit is frequently associated with left unilateral spatial neglect. Severe left neglect dyslexia can be detected with unlimited exposure duration of words or non-words. Minor neglect dyslexia is detected with brief presentation of bilateral words, one in the left and one in the right visual field (phenomenon of contralesional extinction). Neglect dyslexia can be explained as a difficulty in orienting attention to the left side of verbal stimuli. With left posterior lesions, spatial dyslexia is also frequent but multiform. Right neglect dyslexia is frequent, but right unilateral spatial neglect is rare. Attentional dyslexia represents difficulty in selecting a stimulus, letter or word among other similar stimuli; it is a deficit of attentional selection, and the left hemisphere plays a crucial role in selection. Two other types of spatial dyslexia can be found after left posterior lesions: paradoxical ipsilesional extinction and stimulus-centred neglect dyslexia. Disconnections between left or right parietal attentional areas and the left temporal visual word form area could explain these deficits. Overall, a model of attention dissociating modulation, selection control, and selection positioning can help in understanding these reading disorders.

  8. Polarization Aberrations

    NASA Technical Reports Server (NTRS)

    Mcguire, James P., Jr.; Chipman, Russell A.

    1990-01-01

    The analysis of the polarization characteristics displayed by optical systems can be divided into two categories: geometrical and physical. Geometrical analysis calculates the change in polarization of a wavefront between pupils in an optical instrument. Physical analysis propagates the polarized fields wherever the geometrical analysis is not valid, i.e., near the edges of stops, near images, in anisotropic media, etc. Polarization aberration theory provides a starting point for geometrical design and facilitates subsequent optimization. The polarization aberrations described arise from differences in the transmitted (or reflected) amplitudes and phases at interfaces. The polarization aberration matrix (PAM) is calculated for isotropic rotationally symmetric systems through fourth order and includes the interface phase, amplitude, linear diattenuation, and linear retardance aberrations. The exponential form of Jones matrices used are discussed. The PAM in Jones matrix is introduced. The exact calculation of polarization aberrations through polarization ray tracing is described. The report is divided into three sections: I. Rotationally Symmetric Optical Systems; II. Tilted and Decentered Optical Systems; and Polarization Analysis of LIDARs.

  9. Real-time Imaging Orientation Determination System to Verify Imaging Polarization Navigation Algorithm

    PubMed Central

    Lu, Hao; Zhao, Kaichun; Wang, Xiaochu; You, Zheng; Huang, Kaoli

    2016-01-01

    Bio-inspired imaging polarization navigation which can provide navigation information and is capable of sensing polarization information has advantages of high-precision and anti-interference over polarization navigation sensors that use photodiodes. Although all types of imaging polarimeters exist, they may not qualify for the research on the imaging polarization navigation algorithm. To verify the algorithm, a real-time imaging orientation determination system was designed and implemented. Essential calibration procedures for the type of system that contained camera parameter calibration and the inconsistency of complementary metal oxide semiconductor calibration were discussed, designed, and implemented. Calibration results were used to undistort and rectify the multi-camera system. An orientation determination experiment was conducted. The results indicated that the system could acquire and compute the polarized skylight images throughout the calibrations and resolve orientation by the algorithm to verify in real-time. An orientation determination algorithm based on image processing was tested on the system. The performance and properties of the algorithm were evaluated. The rate of the algorithm was over 1 Hz, the error was over 0.313°, and the population standard deviation was 0.148° without any data filter. PMID:26805851

  10. Polar Bear

    USGS Publications Warehouse

    Amstrup, S.D.; ,; Lentfer, J.W.

    1988-01-01

    Polar bears are long-lived, late-maturing carnivores that have relatively low rates of reproduction and natural mortality. Their populations are susceptible to disturbance from human activities, such as the exploration and development of mineral resources or hunting. Polar bear populations have been an important renewable resource available to coastal communities throughout the Arctic for thousands of years.

  11. Macrophage Polarization.

    PubMed

    Murray, Peter J

    2017-02-10

    Macrophage polarization refers to how macrophages have been activated at a given point in space and time. Polarization is not fixed, as macrophages are sufficiently plastic to integrate multiple signals, such as those from microbes, damaged tissues, and the normal tissue environment. Three broad pathways control polarization: epigenetic and cell survival pathways that prolong or shorten macrophage development and viability, the tissue microenvironment, and extrinsic factors, such as microbial products and cytokines released in inflammation. A plethora of advances have provided a framework for rationally purifying, describing, and manipulating macrophage polarization. Here, I assess the current state of knowledge about macrophage polarization and enumerate the major questions about how activated macrophages regulate the physiology of normal and damaged tissues.

  12. 16 CFR 801.2 - Acquiring and acquired persons.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 16 Commercial Practices 1 2013-01-01 2013-01-01 false Acquiring and acquired persons. 801.2 Section 801.2 Commercial Practices FEDERAL TRADE COMMISSION RULES, REGULATIONS, STATEMENTS AND INTERPRETATIONS UNDER THE HART-SCOTT-RODINO ANTITRUST IMPROVEMENTS ACT OF 1976 COVERAGE RULES § 801.2...

  13. 16 CFR 801.2 - Acquiring and acquired persons.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 16 Commercial Practices 1 2010-01-01 2010-01-01 false Acquiring and acquired persons. 801.2 Section 801.2 Commercial Practices FEDERAL TRADE COMMISSION RULES, REGULATIONS, STATEMENTS AND INTERPRETATIONS UNDER THE HART-SCOTT-RODINO ANTITRUST IMPROVEMENTS ACT OF 1976 COVERAGE RULES § 801.2...

  14. 16 CFR 801.2 - Acquiring and acquired persons.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 16 Commercial Practices 1 2012-01-01 2012-01-01 false Acquiring and acquired persons. 801.2 Section 801.2 Commercial Practices FEDERAL TRADE COMMISSION RULES, REGULATIONS, STATEMENTS AND INTERPRETATIONS UNDER THE HART-SCOTT-RODINO ANTITRUST IMPROVEMENTS ACT OF 1976 COVERAGE RULES § 801.2...

  15. 16 CFR 801.2 - Acquiring and acquired persons.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 16 Commercial Practices 1 2014-01-01 2014-01-01 false Acquiring and acquired persons. 801.2 Section 801.2 Commercial Practices FEDERAL TRADE COMMISSION RULES, REGULATIONS, STATEMENTS AND INTERPRETATIONS UNDER THE HART-SCOTT-RODINO ANTITRUST IMPROVEMENTS ACT OF 1976 COVERAGE RULES § 801.2...

  16. 16 CFR 801.2 - Acquiring and acquired persons.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 16 Commercial Practices 1 2011-01-01 2011-01-01 false Acquiring and acquired persons. 801.2 Section 801.2 Commercial Practices FEDERAL TRADE COMMISSION RULES, REGULATIONS, STATEMENTS AND INTERPRETATIONS UNDER THE HART-SCOTT-RODINO ANTITRUST IMPROVEMENTS ACT OF 1976 COVERAGE RULES § 801.2...

  17. Acquired localised hypertrichosis in a Chinese child after cast immobilisation.

    PubMed

    Yuen, M W; Lai, Loretta K P; Chan, P F; Chao, David V K

    2015-08-01

    Hypertrichosis refers to excessive hair growth that is independent of any androgen effect. Hypertrichosis could be congenital or acquired, localised or generalised. The phenomenon of acquired localised hypertrichosis following cast application for a fracture is well known to orthopaedic surgeons, but is rarely encountered by primary care physicians. We describe a 28-month-old Chinese boy who had fracture of right leg as a result of an injury. He had a cast applied by an orthopaedic surgeon as treatment. On removal of the cast 6 weeks later, he was noticed to have significant hair growth on his right leg compared with the left leg. The patient was reassessed 3 months after removal of the cast. The hypertrichosis resolved completely with time. This patient was one of the youngest among the reported cases of acquired localised hypertrichosis after cast application. We illustrate the significance of management of post-cast-acquired localised hypertrichosis in the primary care setting.

  18. Polar Glaciology

    NASA Technical Reports Server (NTRS)

    Robin, G. D.

    1984-01-01

    Two fields of research on polar ice sheets are likely to be of dominant interest during the 1990s. These are: the role of polar ice sheets in the hydrological cycle ocean-atmosphere-ice sheets-oceans, especially in relation to climate change; and the study and interpretation of material in deep ice cores to provide improved knowledge of past climates and of the varying levels of atmospheric constituents such as CO2, NOx, SO2, aerosols, etc., over the past 200,000 years. Both topics require a better knowledge of ice dynamics. Many of the studies that should be undertaken in polar regions by Earth Observing System require similar instruments and techniques to those used elsewhere over oceans and inland surfaces. However to study polar regions two special requirements need to be met: Earth Observing System satellite(s) need to be in a sufficiently high inclination orbit to cover most of the polar regions. Instruments must also be adapted, often by relatively limited changes, to give satisfactory data over polar ice. The observational requirements for polar ice sheets in the 1990s are summarized.

  19. Acquired epidermodysplasia verruciformis in a child with atopic dermatitis.

    PubMed

    Fernandez, Kristen H; Rady, Peter; Tyring, Steven; Stone, Mary S

    2014-01-01

    A 4-year-old girl with an established diagnosis of atopic dermatitis, previously severe and treated with cyclosporine, developed widespread papules that demonstrated changes consistent with epidermodysplasia verruciformis on biopsy. Human papilloma virus (HPV) typing was performed and was consistent with epidermodysplasia verruciformis-type HPV (type 5). These lesions rapidly resolved with a 2-week course of imiquimod. Rapid resolution and no family history of epidermodysplasia verruciformis make this most consistent with acquired epidermodysplasia verruciformis. This case is the first reported case of acquired epidermodysplasia verruciformis in a child without the human immunodeficiency virus and may be linked to cyclosporine use, which also has never been previously reported.

  20. Mycosis fungoides: an important differential diagnosis for acquired palmoplantar keratoderma.

    PubMed

    Kim, Janet; Foster, Rachael; Lam, Minh; Kumarasinghe, Sujith Prasad

    2015-02-01

    Mycosis fungoides is the most common subtype of primary cutaneous lymphoma and has several clinical variants. We report a 74-year-old man presenting with an acquired palmoplantar keratoderma initially diagnosed and treated as psoriasis with suboptimal improvement. Several months later the patient developed patches and plaques that were histologically consistent with mycosis fungoides. These lesions were ameliorated with the treatment of the underlying mycosis fungoides and the palmoplantar keratoderma resolved promptly with radiotherapy. This case highlights the importance of considering mycosis fungoides as an infrequent but serious cause of acquired palmoplantar keratoderma.

  1. Polarizing cues.

    PubMed

    Nicholson, Stephen P

    2012-01-01

    People categorize themselves and others, creating ingroup and outgroup distinctions. In American politics, parties constitute the in- and outgroups, and party leaders hold sway in articulating party positions. A party leader's endorsement of a policy can be persuasive, inducing co-partisans to take the same position. In contrast, a party leader's endorsement may polarize opinion, inducing out-party identifiers to take a contrary position. Using survey experiments from the 2008 presidential election, I examine whether in- and out-party candidate cues—John McCain and Barack Obama—affected partisan opinion. The results indicate that in-party leader cues do not persuade but that out-party leader cues polarize. This finding holds in an experiment featuring President Bush in which his endorsement did not persuade Republicans but it polarized Democrats. Lastly, I compare the effect of party leader cues to party label cues. The results suggest that politicians, not parties, function as polarizing cues.

  2. Time-resolved imaging of material response during laser-induced bulk damage in SiO2

    SciTech Connect

    Demos, S G; Negres, R A

    2008-10-24

    We report on time resolved imaging of the dynamic events taking place during laser-induced damage in the bulk of fused silica samples with nanosecond temporal resolution and one micron spatial resolution. These events include: shock/pressure wave formation and propagation, transient absorption, crack propagation and formation of residual stress fields. The work has been performed using a time-resolved microscope system that utilizes a probe pulse to acquire images at delay times covering the entire timeline of a damage event. Image information is enhanced using polarized illumination and simultaneously recording the two orthogonal polarization image components. For the case of fused silica, an electronic excitation is first observed accompanied by the onset of a pressure wave generation and propagation. Cracks are seen to form early in the process and reach their final size at about 25 ns into the damage event. In addition, changes that in part are attributed to transient absorption in the modified material are observed for delays up to about 200 microseconds.

  3. Hepatocyte Polarity

    PubMed Central

    Treyer, Aleksandr; Müsch, Anne

    2013-01-01

    Hepatocytes, like other epithelia, are situated at the interface between the organism’s exterior and the underlying internal milieu and organize the vectorial exchange of macromolecules between these two spaces. To mediate this function, epithelial cells, including hepatocytes, are polarized with distinct luminal domains that are separated by tight junctions from lateral domains engaged in cell-cell adhesion and from basal domains that interact with the underlying extracellular matrix. Despite these universal principles, hepatocytes distinguish themselves from other nonstriated epithelia by their multipolar organization. Each hepatocyte participates in multiple, narrow lumina, the bile canaliculi, and has multiple basal surfaces that face the endothelial lining. Hepatocytes also differ in the mechanism of luminal protein trafficking from other epithelia studied. They lack polarized protein secretion to the luminal domain and target single-spanning and glycosylphosphatidylinositol-anchored bile canalicular membrane proteins via transcytosis from the basolateral domain. We compare this unique hepatic polarity phenotype with that of the more common columnar epithelial organization and review our current knowledge of the signaling mechanisms and the organization of polarized protein trafficking that govern the establishment and maintenance of hepatic polarity. The serine/threonine kinase LKB1, which is activated by the bile acid taurocholate and, in turn, activates adenosine monophosphate kinase-related kinases including AMPK1/2 and Par1 paralogues has emerged as a key determinant of hepatic polarity. We propose that the absence of a hepatocyte basal lamina and differences in cell-cell adhesion signaling that determine the positioning of tight junctions are two crucial determinants for the distinct hepatic and columnar polarity phenotypes. PMID:23720287

  4. Cilia organize ependymal planar polarity

    PubMed Central

    Mirzadeh, Zaman; Han, Young-Goo; Soriano-Navarro, Mario; García-Verdugo, Jose Manuel; Alvarez-Buylla, Arturo

    2010-01-01

    Multi-ciliated epithelial cells, called ependymal cells, line the ventricles in the adult brain. Most ependymal cells are born prenatally and are derived from radial glia. Ependymal cells have a remarkable planar polarization that determines orientation of ciliary beating and propulsion of cerebrospinal fluid (CSF). Disruption of ependymal ciliary beating, by injury or disease, results in aberrant CSF circulation and hydrocephalus, a common disorder of the central nervous system. Very little is known about the mechanisms guiding ependymal planar polarity and whether this organization is acquired during ependymal cell development or is already present in radial glia. Here we show that basal bodies in ependymal cells in the lateral ventricle walls of adult mice are polarized in two ways: i) rotational; angle of individual basal bodies with respect to their long axis and ii) translational; the position of basal bodies on the apical surface of the cell. Conditional ablation of motile cilia disrupted rotational orientation, but translational polarity was largely preserved. In contrast, translational polarity was dramatically affected when radial glial primary cilia were ablated earlier in development. Remarkably, radial glia in the embryo have a translational polarity that predicts the orientation of mature ependymal cells. These results suggest that ependymal planar cell polarity is a multi-step process initially organized by primary cilia in radial glia and then refined by motile cilia in ependymal cells. PMID:20164345

  5. Cilia organize ependymal planar polarity.

    PubMed

    Mirzadeh, Zaman; Han, Young-Goo; Soriano-Navarro, Mario; García-Verdugo, Jose Manuel; Alvarez-Buylla, Arturo

    2010-02-17

    Multiciliated epithelial cells, called ependymal cells, line the ventricles in the adult brain. Most ependymal cells are born prenatally and are derived from radial glia. Ependymal cells have a remarkable planar polarization that determines orientation of ciliary beating and propulsion of CSF. Disruption of ependymal ciliary beating, by injury or disease, results in aberrant CSF circulation and hydrocephalus, a common disorder of the CNS. Very little is known about the mechanisms guiding ependymal planar polarity and whether this organization is acquired during ependymal cell development or is already present in radial glia. Here we show that basal bodies in ependymal cells in the lateral ventricle walls of adult mice are polarized in two ways: (1) rotational; angle of individual basal bodies with respect to their long axis and (2) translational; the position of basal bodies on the apical surface of the cell. Conditional ablation of motile cilia disrupted rotational orientation, but translational polarity was largely preserved. In contrast, translational polarity was dramatically affected when radial glial primary cilia were ablated earlier in development. Remarkably, radial glia in the embryo have a translational polarity that predicts the orientation of mature ependymal cells. These results suggest that ependymal planar cell polarity is a multistep process initially organized by primary cilia in radial glia and then refined by motile cilia in ependymal cells.

  6. Resolving writer's block.

    PubMed Central

    Huston, P.

    1998-01-01

    PROBLEM BEING ADDRESSED: Writer's block, or a distinctly uncomfortable inability to write, can interfere with professional productivity. OBJECTIVE OF PROGRAM: To identify writer's block and to outline suggestions for its early diagnosis, treatment, and prevention. MAIN COMPONENTS OF PROGRAM: Once the diagnosis has been established, a stepwise approach to care is recommended. Mild blockage can be resolved by evaluating and revising expectations, conducting a task analysis, and giving oneself positive feedback. Moderate blockage can be addressed by creative exercises, such as brainstorming and role-playing. Recalcitrant blockage can be resolved with therapy. Writer's block can be prevented by taking opportunities to write at the beginning of projects, working with a supportive group of people, and cultivating an ongoing interest in writing. CONCLUSIONS: Writer's block is a highly treatable condition. A systematic approach can help to alleviate anxiety, build confidence, and give people the information they need to work productively. PMID:9481467

  7. Coast Guard Polar Icebreaker Modernization: Background and Issues for Congress

    DTIC Science & Technology

    2013-07-24

    polar icebreaker fleet is in need of recapitalization, the decision to acquire this capability through purchase of new vessels, reconstruction of...exactly the same sort of lease versus buy analysis, and in fact, the Coast Guard had a two track procurement strategy to compare leasing a new...scientific research in the Arctic. With the reactivation of Polar Star, the operational U.S. polar icebreaking fleet consists of one heavy polar

  8. Optical detection dental disease using polarized light

    DOEpatents

    Everett, Matthew J.; Colston, Jr., Billy W.; Sathyam, Ujwal S.; Da Silva, Luiz B.; Fried, Daniel

    2003-01-01

    A polarization sensitive optical imaging system is used to detect changes in polarization in dental tissues to aid the diagnosis of dental disease such as caries. The degree of depolarization is measured by illuminating the dental tissue with polarized light and measuring the polarization state of the backscattered light. The polarization state of this reflected light is analyzed using optical polarimetric imaging techniques. A hand-held fiber optic dental probe is used in vivo to direct the incident beam to the dental tissue and collect the reflected light. To provide depth-resolved characterization of the dental tissue, the polarization diagnostics may be incorporated into optical coherence domain reflectometry and optical coherence tomography (OCDR/OCT) systems, which enables identification of subsurface depolarization sites associated with demineralization of enamel or bone.

  9. Polarized Campuses.

    ERIC Educational Resources Information Center

    Parr, Susan Resneck

    1991-01-01

    On college campuses, the climate is polarized because of intolerance and discrimination, censorship, factionalism, and anger among students and faculty. As a result, the campus is in danger of becoming dominated by political issues and discouraging the exchange of ideas characteristic of a true liberal arts education. (MSE)

  10. Non-polar InGaN quantum dot emission with crystal-axis oriented linear polarization

    SciTech Connect

    Reid, Benjamin P. L. Chan, Christopher C. S.; Taylor, Robert A.; Kocher, Claudius; Zhu, Tongtong; Oehler, Fabrice; Oliver, Rachel A.

    2015-04-27

    Polarization sensitive photoluminescence is performed on single non-polar InGaN quantum dots. The studied InGaN quantum dots are found to have linearly polarized emission with a common polarization direction defined by the [0001] crystal axis. Around half of ∼40 studied dots have a polarization degree of 1. For those lines with a polarization degree less than 1, we can resolve fine structure splittings between −800 μeV and +800 μeV, with no clear correlation between fine structure splitting and emission energy.

  11. Angle- and spin-resolved photoemission from ferromagnets

    NASA Astrophysics Data System (ADS)

    Cherepkov, N. A.; Kuznetsov, V. V.

    1996-07-01

    Equations for angle- and spin-resolved photoemission from core levels of ferromagnets are derived using the atomic model. They are applied to the n p subshells and to the particular geometries of experiment with the photoemission normal to the surface, which have been used already in several experiments. It is shown that for these geometries the spin-resolved spectra obtained with linearly polarized light are especially simple and contain the contribution of only one or two magnetic sublevels of the 0953-8984/8/27/008/img5 state, and of only one sublevel of the 0953-8984/8/27/008/img6 state, which allow one to resolve the magnetic splitting of core levels. The use of circularly polarized or unpolarized light gives a less transparent picture.

  12. Polarized light detection in spiders.

    PubMed

    Dacke, M; Doan, T A; O'Carroll, D C

    2001-07-01

    We describe here the detection of polarized light by the simple eyes of spiders. Using behavioural, morphological, electrophysiological and optical studies, we show that spiders have evolved two different mechanisms to resolve the e-vector of light. Wolf spiders (Lycosidae), are able to turn in response to rotation of a polarized pattern at the zenith of their visual fields, and we also describe a strip in the ventral retina of the principal (anterio-median) eyes that views this location and has receptors tiered into two layers. This provides each pair of receptors with a similar optical solution to that provided by the 'dorsal rim area' of the insect compound eye. In contrast, gnaphosid spiders have evolved a pair of lensless secondary eyes for the detection of polarized light. These two eyes, each sensitive to orthogonal directions of polarization, are perfectly designed to integrate signals from the larger part of the sky and cooperate to analyse the polarization of light. Built-in polarizers help to improve signal purity. Similar organisation in the eyes of several other spider families suggests that these two mechanisms are not restricted to only a few families.

  13. A model of plant canopy polarization response

    NASA Technical Reports Server (NTRS)

    Vanderbilt, V. C.

    1980-01-01

    Sensors to remotely measure the linear polarization of ground scenes have been proposed for the Multispectral Resource Sampler (MRS), a satellite sensor system proposed to complement the Thematic Mapper. At present justification for a sensor on MRS to measure scene polarization is limited. This paper discusses a model for the amount of linearly polarized light reflected by the shiny leaves of such crops as wheat, corn, and sorghum. The theory demonstrates that, potentially, measurements of the linearly polarized light from a crop canopy may be used as an additional feature to discriminate between crops. Examination of the model suggests that, potentially, satellite polarization measurements may be used to monitor crop development stage, leaf water content, leaf area index, hail damage, and certain plant diseases. The model adds to the understanding of the potential information content of scene polarization measurements acquired by future satellite sensor systems such as MRS.

  14. Terahertz polarization imaging for colon cancer detection

    NASA Astrophysics Data System (ADS)

    Doradla, Pallavi; Alavi, Karim; Joseph, Cecil S.; Giles, Robert H.

    2014-03-01

    Continuous wave terahertz (THz) imaging has the potential to offer a safe, noninvasive medical imaging modality for delineating colorectal cancer. The terahertz reflectance measurements of fresh 3 - 5 mm thick human colonic excisions were acquired using a continuous-wave polarization imaging technique. A CO2 optically pumped Far- Infrared molecular gas laser operating at 584 GHz was used to illuminate the colon tissue, while the reflected signals were detected using a liquid Helium cooled silicon bolometer. Both co-polarized and cross-polarized remittance from the samples was collected using wire grid polarizers in the experiment. The experimental analysis of 2D images obtained from THz reflection polarization imaging techniques showed intrinsic contrast between cancerous and normal regions based on increased reflection from the tumor. Also, the study demonstrates that the cross-polarized terahertz images not only correlates better with the histology, but also provide consistent relative reflectance difference values between normal and cancerous regions for all the measured specimens.

  15. Resource Prospector: The RESOLVE Payload

    NASA Astrophysics Data System (ADS)

    Quinn, J.; Smith, J.; J., Captain; Paz, A.; Colaprete, A.; Elphic, R.; Zacny, K.

    2015-10-01

    NASA has been developing a lunar volatiles exploration payload named RESOLVE. Now the primary science payload on-board the Resource Prospector (RP) mission, RESOLVE, consists of several instruments that evaluate lunar volatiles.

  16. Full Stokes polarization imaging camera

    NASA Astrophysics Data System (ADS)

    Vedel, M.; Breugnot, S.; Lechocinski, N.

    2011-10-01

    Objective and background: We present a new version of Bossa Nova Technologies' passive polarization imaging camera. The previous version was performing live measurement of the Linear Stokes parameters (S0, S1, S2), and its derivatives. This new version presented in this paper performs live measurement of Full Stokes parameters, i.e. including the fourth parameter S3 related to the amount of circular polarization. Dedicated software was developed to provide live images of any Stokes related parameters such as the Degree Of Linear Polarization (DOLP), the Degree Of Circular Polarization (DOCP), the Angle Of Polarization (AOP). Results: We first we give a brief description of the camera and its technology. It is a Division Of Time Polarimeter using a custom ferroelectric liquid crystal cell. A description of the method used to calculate Data Reduction Matrix (DRM)5,9 linking intensity measurements and the Stokes parameters is given. The calibration was developed in order to maximize the condition number of the DRM. It also allows very efficient post processing of the images acquired. Complete evaluation of the precision of standard polarization parameters is described. We further present the standard features of the dedicated software that was developed to operate the camera. It provides live images of the Stokes vector components and the usual associated parameters. Finally some tests already conducted are presented. It includes indoor laboratory and outdoor measurements. This new camera will be a useful tool for many applications such as biomedical, remote sensing, metrology, material studies, and others.

  17. South Polar Residual Ice Cap

    NASA Technical Reports Server (NTRS)

    1990-01-01

    This mosaic is composed of 18 Viking Orbiter images (6 each in red, green, and violet filters), acquired on September 28, 1977, during revolution 407 of Viking Orbiter 2. The south pole is located just off the lower left edge of the polar cap, and the 0 degree longitude meridian extends toward the top of the mosaic. The large crater near the right edge (named 'South') is about 100 km in diameter. These images were acquired during southern summer on Mars (Ls = 341 degrees); the sub-solar declination was 8 degrees S., and the south polar cap was nearing its final stage of retreat just prior to vernal equinox. The south residual cap is approximately 400 km across, and the exposed surface is thought to consist dominantly of carbon-dioxide frost. This is in contrast to the water-ice surface of the north polar residual cap. It is likely that water ice is present in layers that underlie the south polar cap and that comprise the surrounding layered terrains. Near the top of this image, irregular pits with sharp-rimmed cliffs appear 'etched', presumably by wind. A series of rugged mountains (extending toward the upper right corner of the image) are of unknown origin.

  18. Dual Brushless Resolver Rate Sensor

    NASA Technical Reports Server (NTRS)

    Howard, David E. (Inventor)

    1997-01-01

    A resolver rate sensor is disclosed in which dual brushless resolvers are mechanically coupled to the same output shaft. Diverse inputs are provided to each resolver by providing the first resolver with a DC input and the second resolver with an AC sinusoidal input. A trigonometric identity in which the sum of the squares of the sin and cosine components equal one is used to advantage in providing a sensor of increased accuracy. The first resolver may have a fixed or variable DC input to permit dynamic adjustment of resolver sensitivity thus permitting a wide range of coverage. In one embodiment of the invention the outputs of the first resolver are directly inputted into two separate multipliers and the outputs of the second resolver are inputted into the two separate multipliers, after being demodulated in a pair of demodulator circuits. The multiplied signals are then added in an adder circuit to provide a directional sensitive output. In another embodiment the outputs from the first resolver is modulated in separate modulator circuits and the output from the modulator circuits are used to excite the second resolver. The outputs from the second resolver are demodulated in separate demodulator circuit and added in an adder circuit to provide a direction sensitive rate output.

  19. Polar Diving

    NASA Technical Reports Server (NTRS)

    2006-01-01

    3 July 2006 This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows layers exposed by erosion in a trough within the north polar residual cap of Mars, diving beneath a younger covering of polar materials. The layers have, since the Mariner 9 mission in 1972, been interpreted to be composed of a combination of dust and ice in unknown proportions. In this scene, a layer of solid carbon dioxide, which was deposited during the previous autumn and winter, blankets the trough as well as the adjacent terrain. Throughout northern spring, the carbon dioxide will be removed; by summer, the layers will be frost-free.

    Location near: 81.4oN, 352.2oW Image width: 3 km (1.9 mi) Illumination from: lower left Season: Northern Spring

  20. Cell polarity

    PubMed Central

    Romereim, Sarah M

    2011-01-01

    Despite extensive genetic analysis of the dynamic multi-phase process that transforms a small population of lateral plate mesoderm into the mature limb skeleton, the mechanisms by which signaling pathways regulate cellular behaviors to generate morphogenetic forces are not known. Recently, a series of papers have offered the intriguing possibility that regulated cell polarity fine-tunes the morphogenetic process via orienting cell axes, division planes and cell movements. Wnt5a-mediated non-canonical signaling, which may include planar cell polarity, has emerged as a common thread in the otherwise distinct signaling networks that regulate morphogenesis in each phase of limb development. These findings position the limb as a key model to elucidate how global tissue patterning pathways direct local differences in cell behavior that, in turn, generate growth and form. PMID:22064549

  1. Musicality: instinct or acquired skill?

    PubMed

    Marcus, Gary F

    2012-10-01

    Is the human tendency toward musicality better thought of as the product of a specific, evolved instinct or an acquired skill? Developmental and evolutionary arguments are considered, along with issues of domain-specificity. The article also considers the question of why humans might be consistently and intensely drawn to music if musicality is not in fact the product of a specifically evolved instinct.

  2. Duplicated Information Acquired by Libraries.

    ERIC Educational Resources Information Center

    White, Carl M.

    The object of this study is to make a start toward determining the extent of duplicated information that is being acquired in spite of customary precautions to avoid it. Referring to a specific case, the percentages in Table II show the frequency of appearance in five other works of 19 items in Mitchell's "Encyclopedia of American Politics." While…

  3. Acquired aplastic anemia in children.

    PubMed

    Hartung, Helge D; Olson, Timothy S; Bessler, Monica

    2013-12-01

    This article provides a practice-based and concise review of the etiology, diagnosis, and management of acquired aplastic anemia in children. Bone marrow transplantation, immunosuppressive therapy, and supportive care are discussed in detail. The aim is to provide the clinician with a better understanding of the disease and to offer guidelines for the management of children with this uncommon yet serious disorder.

  4. Brief resolved unexplained event

    PubMed Central

    Arane, Karen; Claudius, Ilene; Goldman, Ran D.

    2017-01-01

    Abstract Question For many years, the term apparent life-threatening event (ALTE) was associated with sudden infant death syndrome, and parents who described an acute event in their infants were sent to the hospital for admission. I understand that for infants new terminology is recommended. What is the current approach to a near-death experience of an infant? Answer A recent clinical practice guideline revised the name and definition of an ALTE to a brief resolved unexplained event (BRUE). The diagnosis of BRUE in infants younger than 1 year of age is made when infants experience 1 of the following BRUE symptoms: a brief episode (ie, less than 1 minute and usually less than 20 to 30 seconds) that is entirely resolved (infant is at baseline), which remains unexplained after the history and physical examination are completed, and includes an event characterized by cyanosis or pallor; absent, decreased, or irregular breathing; hypertonia or hypotonia; or altered responsiveness. Low-risk infants should not be admitted to the hospital and overtesting is discouraged. PMID:28115439

  5. Cloud Resolving Modeling

    NASA Technical Reports Server (NTRS)

    Tao, Wei-Kuo

    2007-01-01

    One of the most promising methods to test the representation of cloud processes used in climate models is to use observations together with cloud-resolving models (CRMs). CRMs use more sophisticated and realistic representations of cloud microphysical processes, and they can reasonably well resolve the time evolution, structure, and life cycles of clouds and cloud systems (with sizes ranging from about 2-200 km). CRMs also allow for explicit interaction between clouds, outgoing longwave (cooling) and incoming solar (heating) radiation, and ocean and land surface processes. Observations are required to initialize CRMs and to validate their results. This paper provides a brief discussion and review of the main characteristics of CRMs as well as some of their major applications. These include the use of CRMs to improve our understanding of: (1) convective organization, (2) cloud temperature and water vapor budgets, and convective momentum transport, (3) diurnal variation of precipitation processes, (4) radiative-convective quasi-equilibrium states, (5) cloud-chemistry interaction, (6) aerosol-precipitation interaction, and (7) improving moist processes in large-scale models. In addition, current and future developments and applications of CRMs will be presented.

  6. RESOLVE 2010 Field Test

    NASA Technical Reports Server (NTRS)

    Captain, J.; Quinn, J.; Moss, T.; Weis, K.

    2010-01-01

    This slide presentation reviews the field tests conducted in 2010 of the Regolith Environment Science & Oxygen & Lunar Volatile Extraction (RESOLVE). The Resolve program consist of several mechanism: (1) Excavation and Bulk Regolith Characterization (EBRC) which is designed to act as a drill and crusher, (2) Regolith Volatiles Characterization (RVC) which is a reactor and does gas analysis,(3) Lunar Water Resources Demonstration (LWRD) which is a fluid system, water and hydrogen capture device and (4) the Rover. The scientific goal of this test is to demonstrate evolution of low levels of hydrogen and water as a function of temperature. The Engineering goals of this test are to demonstrate:(1) Integration onto new rover (2) Miniaturization of electronics rack (3) Operation from battery packs (elimination of generator) (4) Remote command/control and (5) Operation while roving. Views of the 2008 and the 2010 mechanisms, a overhead view of the mission path, a view of the terrain, the two drill sites, and a graphic of the Master Events Controller Graphical User Interface (MEC GUI) are shown. There are descriptions of the Gas chromatography (GC), the operational procedure, water and hydrogen doping of tephra. There is also a review of some of the results, and future direction for research and tests.

  7. South Polar Knob

    NASA Technical Reports Server (NTRS)

    2005-01-01

    1 July 2005 This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows a small, relatively light-toned knob of layered material, and the erosional expression of the underlying layers, in the south polar region of Mars. When the image was acquired in April 2005, the surface was still covered with seasonal carbon dioxide frost. Dark spots and streaks mark locations where the frost had begun to change and sublime away.

    Location near: 84.2oS, 138.3oW Image width: 3 km (1.9 mi) Illumination from: upper left Season Southern Spring

  8. Frosty Polar Slope

    NASA Technical Reports Server (NTRS)

    2004-01-01

    11 August 2004 Acquired just last week on 3 August 2004, this Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows a dark, layered scarp in the martian north polar region. All of the light-toned surfaces in this image are covered by frost left over from the previous winter. On the scarp, about half of the surfaces once covered by frost are now exposed (as the frost has sublimed away), leaving a large number of bright patches. These patches of frost enhance the appearance of layering on the slopes. This image is located near 81.8oN, 84.4oW. The image covers an area 3 km (1.9 mi) wide, and is illuminated by sunlight from the lower left.

  9. Multi-frequency, multi-polarization SAR and radiometer sea ice classification

    NASA Technical Reports Server (NTRS)

    Drinkwater, Mark R.; Crawford, John P.; Cavalieri, Donald J.

    1991-01-01

    Microwave remotely sensed data were acquired simultaneously in March 1988 over Beaufort, Chukchi, and Bering Sea ice using the JPL multifrequency, polarimetric synthetic aperture radar (SAR), and multifrequency dual-polarization GSFC radiometer. The experiment was conducted as a series of coordinated underflights of the DMSP SSM/I satellite radiometer to validate ice products derived from its radiance values. Concurrent flights by an NRL P-3 aircraft enabled overlapping high-resolution, single-frequency images to be acquired over the same surfaces using a Ka-band scanning microwave radiometer. Precise coregistration to an accuracy of 100 m, +/- 25 m enables comparison of temporally and spatially coincident active and passive microwave datasets. Three-channel polarimetric SAR data are compared with dual-polarized radiometer data at several SSM/I frequencies, showing backscatter signatures to be highly correlated with radiometric temperatures. Further comparisons are used to evaluate ice concentration retrievals and to show how multiparameter datasets can be used to resolve ambiguities present in identifying certain sea ice forms with a single microwave instrument.

  10. Representing and Acquiring Geographic Knowledge.

    DTIC Science & Technology

    1984-01-01

    Management, Inc. 5 copies 1300 Wilson Boulevard, Suite 102 Arlington, Virginia 22209 Ms. Robin Dillard 1 copy Naval Ocean System Center C2 Information...the road. Conceivably, it could curl round and come closer to *the pond at some other point. We mus,. therefore ask for the minimal distance between...both of th’se. There is no general scheme for resolving these interactions. Rather, we must simply decide priorities , and force the lower priority

  11. Spatially resolved multicomponent gels

    NASA Astrophysics Data System (ADS)

    Draper, Emily R.; Eden, Edward G. B.; McDonald, Tom O.; Adams, Dave J.

    2015-10-01

    Multicomponent supramolecular systems could be used to prepare exciting new functional materials, but it is often challenging to control the assembly across multiple length scales. Here we report a simple approach to forming patterned, spatially resolved multicomponent supramolecular hydrogels. A multicomponent gel is first formed from two low-molecular-weight gelators and consists of two types of fibre, each formed by only one gelator. One type of fibre in this ‘self-sorted network’ is then removed selectively by a light-triggered gel-to-sol transition. We show that the remaining network has the same mechanical properties as it would have done if it initially formed alone. The selective irradiation of sections of the gel through a mask leads to the formation of patterned multicomponent networks, in which either one or two networks can be present at a particular position with a high degree of spatial control.

  12. Nursing home-acquired pneumonia.

    PubMed

    El Solh, Ali A

    2009-02-01

    Nursing home-acquired pneumonia (NHAP) was first described in 1978. Since then there has been much written regarding NHAP and its management despite the lack of well-designed studies in this patient population. The most characteristic features of patients with NHAP are the atypical presentation, which may lead to delay in diagnosis and therapy. The microbial etiology of pneumonia encompasses a wide spectrum that spans microbes recovered from patients with community-acquired pneumonia to organisms considered specific only to nosocomial settings. Decision to transfer a nursing home patient to an acute care facility depends on a host of factors, which include the level of staffing available at the nursing home, patients' advance directives, and complexity of treatment. The presence of risk factors for multidrug-resistant pathogens dictates approach to therapy. Prevention remains the cornerstone of reducing the incidence of disease. Despite the advance in medical services, mortality from NHAP remains high.

  13. Occupationally Acquired American Cutaneous Leishmaniasis

    PubMed Central

    Felinto de Brito, Maria Edileuza; Andrade, Maria Sandra; de Almeida, Éricka Lima; Medeiros, Ângela Cristina Rapela; Werkhäuser, Roberto Pereira; de Araújo, Ana Isabele Freitas; Brandão-Filho, Sinval Pinto; Paiva de Almeida, Alzira Maria; Gomes Rodrigues, Eduardo Henrique

    2012-01-01

    We report two occupationally acquired cases of American cutaneous leishmaniasis (ACL): one accidental laboratory autoinoculation by contaminated needlestick while handling an ACL lesion sample, and one acquired during field studies on bird biology. Polymerase chain reaction (PCR) assays of patient lesions were positive for Leishmania, subgenus Viannia. One isolate was obtained by culture (from patient 2 biopsy samples) and characterized as Leishmania (Viannia) naiffi through an indirect immunofluorescence assay (IFA) with species-specific monoclonal antibodies (mAbs) and by multilocus enzyme electrophoresis (MLEE). Patients were successfully treated with N-methyl-glucamine. These two cases highlight the potential risks of laboratory and field work and the need to comply with strict biosafety procedures in daily routines. The swab collection method, coupled with PCR detection, has greatly improved ACL laboratory diagnosis. PMID:23227369

  14. [Acquired disorders of color vision].

    PubMed

    Lascu, Lidia; Balaş, Mihaela

    2002-01-01

    This article is a general view of acquired disorders of color vision. The revision of the best known methods and of the etiopathogenic classification is not very important in ophthalmology but on the other hand, the detection of the blue defect advertise and associated ocular pathology. There is a major interest in serious diseases as multiple sclerosis, AIDS, diabetes melitus, when the first ocular sign can be a defect in the color vision.

  15. Probing absolute spin polarization at the nanoscale.

    PubMed

    Eltschka, Matthias; Jäck, Berthold; Assig, Maximilian; Kondrashov, Oleg V; Skvortsov, Mikhail A; Etzkorn, Markus; Ast, Christian R; Kern, Klaus

    2014-12-10

    Probing absolute values of spin polarization at the nanoscale offers insight into the fundamental mechanisms of spin-dependent transport. Employing the Zeeman splitting in superconducting tips (Meservey-Tedrow-Fulde effect), we introduce a novel spin-polarized scanning tunneling microscopy that combines the probing capability of the absolute values of spin polarization with precise control at the atomic scale. We utilize our novel approach to measure the locally resolved spin polarization of magnetic Co nanoislands on Cu(111). We find that the spin polarization is enhanced by 65% when increasing the width of the tunnel barrier by only 2.3 Å due to the different decay of the electron orbitals into vacuum.

  16. Polar Terrains

    NASA Technical Reports Server (NTRS)

    2005-01-01

    [figure removed for brevity, see original site] Context image for PIA03577 Polar Terrains

    The region surrounding the South Polar Cap contains many different terrain types. This image shows both etched terrain and a region of 'mounds'.

    Image information: VIS instrument. Latitude 75S, Longitude 286.5E. 17 meter/pixel resolution.

    Note: this THEMIS visual image has not been radiometrically nor geometrically calibrated for this preliminary release. An empirical correction has been performed to remove instrumental effects. A linear shift has been applied in the cross-track and down-track direction to approximate spacecraft and planetary motion. Fully calibrated and geometrically projected images will be released through the Planetary Data System in accordance with Project policies at a later time.

    NASA's Jet Propulsion Laboratory manages the 2001 Mars Odyssey mission for NASA's Office of Space Science, Washington, D.C. The Thermal Emission Imaging System (THEMIS) was developed by Arizona State University, Tempe, in collaboration with Raytheon Santa Barbara Remote Sensing. The THEMIS investigation is led by Dr. Philip Christensen at Arizona State University. Lockheed Martin Astronautics, Denver, is the prime contractor for the Odyssey project, and developed and built the orbiter. Mission operations are conducted jointly from Lockheed Martin and from JPL, a division of the California Institute of Technology in Pasadena.

  17. Polar ozone

    NASA Technical Reports Server (NTRS)

    Solomon, S.; Grose, W. L.; Jones, R. L.; Mccormick, M. P.; Molina, Mario J.; Oneill, A.; Poole, L. R.; Shine, K. P.; Plumb, R. A.; Pope, V.

    1990-01-01

    The observation and interpretation of a large, unexpected ozone depletion over Antarctica has changed the international scientific view of stratospheric chemistry. The observations which show the veracity, seasonal nature, and vertical structure of the Antarctic ozone hole are presented. Evidence for Arctic and midlatitude ozone loss is also discussed. The chemical theory for Antarctic ozone depletion centers around the occurrence of polar stratospheric clouds (PSCs) in Antarctic winter and spring; the climatology and radiative properties of these clouds are presented. Lab studies of the physical properties of PSCs and the chemical processes that subsequently influence ozone depletion are discussed. Observations and interpretation of the chemical composition of the Antarctic stratosphere are described. It is shown that the observed, greatly enhanced abundances of chlorine monoxide in the lower stratosphere are sufficient to explain much if not all of the ozone decrease. The dynamic meteorology of both polar regions is given, interannual and interhemispheric variations in dynamical processes are outlined, and their likely roles in ozone loss are discussed.

  18. Polarized neutron radiography with a periscope

    NASA Astrophysics Data System (ADS)

    Schulz, Michael; Neubauer, Andreas; Mühlbauer, Martin; Calzada, Elbio; Schillinger, Burkhard; Pfleiderer, Christian; Böni, Peter

    2010-01-01

    The interaction of the magnetic moment of the neutron with magnetic fields provides a powerful probe for spatially resolved magnetisation measurements in magnetic materials. We have tested a periscope as a new type of polarizer providing neutron beams with a high polarization and a low divergence. The observed inhomogeneity of the beam caused by the waviness of the glass substrates was quantified by means of Monte-Carlo simulations using the software package McStas. The results show that beams of high homogeneity can be produced if the waviness is reduced to below 1.0·10-5 rad. Finally, it is shown that radiography with polarized neutrons is a powerful method for measuring the spatially resolved magnetisation in optically float-zoned samples of the weak itinerant ferromagnet Ni3Al, thereby aiding the identification of the appropriate growth parameters.

  19. Polarization Phase-Shift Interferometry: A Simple Laboratory Setup

    NASA Astrophysics Data System (ADS)

    Vannoni, Maurizio; Trivi, Marcelo; Molesini, Giuseppe

    2008-04-01

    An interferometry experiment is proposed, working on a Twyman-Green optical configuration. The interferogram is acquired with a digital camera and processed. Using polarization components the interferogram is phase-shifted and four different interferograms are acquired. The experiment is proposed as an introduction to modern phase-shift interferometry, using concepts and laboratory equipment at the level of undergraduate optics courses.

  20. METHOD AND APPARATUS FOR PRODUCING AND ANALYZING POLARIZED GAMMA RADIATION

    DOEpatents

    Hamermesh, M.; Hanna, S.S.; Perlow, G.J.

    1964-04-21

    A method of polarizing and resolving the plane of polarization of gamma rays is described. Polarization is produced by positioning a thin disc of ferromagnetic metal, cortaining /sup 57/Co, in a magnetic field. Resolution is accomplished by rotating a thin disc of iron enriched in /sup 57/Fe relative to a second magnetic field and noting the change of gamma absorption at each rotational position. (AEC)

  1. Polarization sensitive optical coherence tomography for quantifying the severity of natural caries lesions on occlusal surfaces

    NASA Astrophysics Data System (ADS)

    Fried, Daniel; Ngaotheppitak, Patara; Darling, Cynthia L.; Ho, Chi M.

    2007-02-01

    Previous studies have demonstrated that Polarization Sensitive Optical Coherence Tomography (PS-OCT) can be used to image early dental caries. The purpose of this study was to compare the measured integrated reflectivity of natural caries lesions with the mineral loss measured using digital microradiography in order to determine if PS-OCT can be used as a nondestructive in vivo method to measure the severity of dental decay in the important occlusal surfaces. A PS-OCT system operating at 1310-nm was used to acquire polarization resolved images of natural caries lesions on the occlusal surfaces of extracted teeth. The integrated reflectivity from lesion areas was compared to the integrated mineral loss from the same lesion area measured using digital microradiography. There was a strong correlation between the integrated mineral loss of the caries lesion measured using high resolution digital microradiography and the integrated reflectivity in the perpendicular polarization axis of the PS-OCT system demonstrating the potential for this method to nondestructively monitor the severity of caries lesion in the occlusal pit and fissure where most new decay is found. Although we find these results encouraging, we desire a higher correlation between the integrated mineral loss and the integrated reflectivity and we believe a higher correlation is attainable with better matching of the PS-OCT scans and the histological thin sections.

  2. Sky light polarization detection with linear polarizer triplet in light field camera inspired by insect vision.

    PubMed

    Zhang, Wenjing; Cao, Yu; Zhang, Xuanzhe; Liu, Zejin

    2015-10-20

    Stable information of a sky light polarization pattern can be used for navigation with various advantages such as better performance of anti-interference, no "error cumulative effect," and so on. But the existing method of sky light polarization measurement is weak in real-time performance or with a complex system. Inspired by the navigational capability of a Cataglyphis with its compound eyes, we introduce a new approach to acquire the all-sky image under different polarization directions with one camera and without a rotating polarizer, so as to detect the polarization pattern across the full sky in a single snapshot. Our system is based on a handheld light field camera with a wide-angle lens and a triplet linear polarizer placed over its aperture stop. Experimental results agree with the theoretical predictions. Not only real-time detection but simple and costless architecture demonstrates the superiority of the approach proposed in this paper.

  3. Acquired Upper Extremity Growth Arrest.

    PubMed

    Gauger, Erich M; Casnovsky, Lauren L; Gauger, Erica J; Bohn, Deborah C; Van Heest, Ann E

    2016-09-29

    This study reviewed the clinical history and management of acquired growth arrest in the upper extremity in pediatric patients. The records of all patients presenting from 1996 to 2012 with radiographically proven acquired growth arrest were reviewed. Records were examined to determine the etiology and site of growth arrest, management, and complications. Patients with tumors or hereditary etiology were excluded. A total of 44 patients (24 boys and 20 girls) with 51 physeal arrests who presented at a mean age of 10.6 years (range, 0.8-18.2 years) were included in the study. The distal radius was the most common site (n=24), followed by the distal humerus (n=8), metacarpal (n=6), distal ulna (n=5), proximal humerus (n=4), radial head (n=3), and olecranon (n=1). Growth arrest was secondary to trauma (n=22), infection (n=11), idiopathy (n=6), inflammation (n=2), compartment syndrome (n=2), and avascular necrosis (n=1). Twenty-six patients (59%) underwent surgical intervention to address deformity caused by the physeal arrest. Operative procedures included ipsilateral unaffected bone epiphysiodesis (n=21), shortening osteotomy (n=10), lengthening osteotomy (n=8), excision of physeal bar or bone fragment (n=2), angular correction osteotomy (n=1), and creation of single bone forearm (n=1). Four complications occurred; 3 of these required additional procedures. Acquired upper extremity growth arrest usually is caused by trauma or infection, and the most frequent site is the distal radius. Growth disturbances due to premature arrest can be treated effectively with epiphysiodesis or osteotomy. In this series, the specific site of anatomic growth arrest was the primary factor in determining treatment. [Orthopedics. 201x; xx(x):xx-xx.].

  4. Polarization discrimination of coherently propagating light in turbid media

    SciTech Connect

    Sankaran, V.; Schoenenberger, K.; Maitland, D.J.; Walsh, J.T. Jr.

    1999-07-01

    We describe the use of degree of polarization to discriminate unscattered and weakly scattered light from multiply scattered light in an optically turbid material. We use spatially resolved measurements of the degree of polarization to compare how well linearly and circularly polarized light survives in a sample. Experiments were performed on common tissue phantoms consisting of polystyrene and Intralipid microsphere suspensions and on adipose and arterial tissue. The results indicate that polarization is maintained even after unpolarized irradiance through each sample has been extinguished by several orders of magnitude. The results show that polarized light propagation in common tissue phantoms is distinctly different from polarized light propagation in the two tissues investigated. Further, these experiments illustrate when polarization is an effective discrimination criterion and when it is not. The potential of a polarization-based discrimination scheme to image through the biological and nonbiological samples investigated here is also discussed. {copyright} 1999 Optical Society of America

  5. Acquired 5-oxoproline acidemia successfully treated with N-acetylcysteine

    PubMed Central

    Fenves, Andrew Z.

    2017-01-01

    Acquired 5-oxoprolinemia is increasingly recognized as a cause of anion gap metabolic acidosis. It predominantly occurs in chronically ill, malnourished women with impaired renal function and chronic acetaminophen ingestion. Depletion of glutathione and cysteine stores leads to elevated 5-oxoproline levels. N-acetylcysteine, given its effect in repleting glutathione and cysteine stores, has been proposed as a potential treatment for 5-oxoprolinemia, though reports of its successful use are lacking. We present a case of 5-oxoproline metabolic acidosis that persisted despite discontinuation of acetaminophen. However, the acidosis rapidly resolved with N-acetylcysteine administration.

  6. Polymorphous hemangioendothelioma in a child with acquired immunodeficiency syndrome (AIDS).

    PubMed

    Paul, Stephan R; Hurford, Matthew T; Miettinen, Markku M; Aronoff, Stephen C; Delvecchio, Michael; Grewal, Harsh; Tuluc, Madalina

    2008-03-01

    Polymorphous hemangioendotheliomas (PH) are rare and borderline malignant tumors that are among the wide range of vascular tumors. We report here a 13-year-old male presenting with a history of weight loss, opportunistic infections, and lymphadenopathy. He was determined to be HIV positive and to have acquired immunodeficiency syndrome (AIDS). A biopsy of a femoral node was diagnostic of PH. His systemic lymphadenopathy appeared to resolve with anti-retroviral therapy. This tumor should be considered within the differential diagnoses of pediatric and immunocompromised patients.

  7. Polar Barchans

    NASA Technical Reports Server (NTRS)

    2004-01-01

    20 July 2004 This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows dark, barchan sand dunes of the north polar region of Mars. Barchan dunes are simple, rounded forms with two horns that extend downwind. Inequalities in local wind patterns may result in one horn being extended farther than the other, as is the case for several dunes in this image. The image also shows several barchans may merge to form a long dune ridge. The horns and attendant slip faces on these dunes indicate wind transport of sand from the upper left toward the lower right. The image is located near 77.6oN, 103.6oW. The picture covers an area about 3 km (1.9 mi) wide; sunlight illuminates the scene from the lower left.

  8. The inhibition of acquired fear.

    PubMed

    Izquierdo, Iván; Cammarota, Martín; Vianna, Mónica M R; Bevilaqua, Lía R M

    2004-01-01

    A conditioned stimulus (CS) associated with a fearsome unconditioned stimulus (US) generates learned fear. Acquired fear is at the root of a variety of mental disorders, among which phobias, generalized anxiety, the posttraumatic stress disorder (PTSD) and some forms of depression. The simplest way to inhibit learned fear is to extinguish it, which is usually done by repeatedly presenting the CS alone, so that a new association, CS-"no US", will eventually overcome the previously acquired CS-US association. Extinction was first described by Pavlov as a form of "internal inhibition" and was recommended by Freud and Ferenczi in the 1920s (who called it "habituation") as the treatment of choice for phobic disorders. It is used with success till this day, often in association with anxiolytic drugs. Extinction has since then been applied, also successfully and also often in association with anxiolytics, to the treatment of panic, generalized anxiety disorders and, more recently, PTSD. Extinction of learned fear involves gene expression, protein synthesis, N-methyl-D-aspartate (NMDA) receptors and signaling pathways in the hippocampus and the amygdala at the time of the first CS-no US association. It can be enhanced by increasing the exposure to the "no US" component at the time of behavioral testing, to the point of causing the complete uninstallment of the original fear response. Some theorists have recently proposed that reiteration of the CS alone may induce a reconsolidation of the learned behavior instead of its extinction. Reconsolidation would preserve the original memory from the labilization induced by its retrieval. If true, this would of course be disastrous for the psychotherapy of fear-motivated disorders. Here we show that neither the CS nor retrieval cause anything remotely like reconsolidation, but just extinction. In fact, our findings indicate that the reconsolidation hypothesis is essentially incorrect, at least for the form of contextual fear most

  9. Foodborne listeriosis acquired in hospitals.

    PubMed

    Silk, Benjamin J; McCoy, Morgan H; Iwamoto, Martha; Griffin, Patricia M

    2014-08-15

    Listeriosis is characterized by bacteremia or meningitis. We searched for listeriosis case series and outbreak investigations published in English by 2013, and assessed the strength of evidence for foodborne acquisition among patients who ate hospital food. We identified 30 reports from 13 countries. Among the case series, the median proportion of cases considered to be hospital-acquired was 25% (range, 9%-67%). The median number of outbreak-related illnesses considered to be hospital-acquired was 4.0 (range, 2-16). All patients were immunosuppressed in 18 of 24 (75%) reports with available data. Eight outbreak reports with strong evidence for foodborne acquisition in a hospital implicated sandwiches (3 reports), butter, precut celery, Camembert cheese, sausage, and tuna salad (1 report each). Foodborne acquisition of listeriosis among hospitalized patients is well documented internationally. The number of listeriosis cases could be reduced substantially by establishing hospital policies for safe food preparation for immunocompromised patients and by not serving them higher-risk foods.

  10. [Acquired methemoglobinemia--case report].

    PubMed

    Paczek, Anna; Wawrzyńska, Liliana; Mendek-Czajkowska, Ewa; Kober, Jarosław; Torbicki, Adam

    2010-01-01

    Methemoglobinemia; an increased concentration of methemoglobin in the blood, is an altered state of hemoglobin whereby the ferrous form of iron is oxidized to the ferric state, rendering the heme moiety incapable of carrying oxygen. The authors present a case of 49-year-old man who was admitted to the department of chest medicine with dyspnea, weakness and cyanosis in whom differential diagnosis excluded acute and chronic pulmonary and cardiovascular disease. Clinical cyanosis and low measured oxygen saturation in the presence of normal arterial oxygen tension was highly suggestive of methemoglobinemia ("saturation gap"). Methemoglobin level, measured at the acute phase of disease was elevated at 16%. Episode resolved spontaneously. Causes of methemoglobinemia was not established.

  11. The dynamics of spatially-resolved laser eigenstates

    SciTech Connect

    Bretenaker, F.; LeFloch, A. )

    1990-09-01

    The existence of partially spatially-resolved laser eigenstates is proven, using the polarization walkoff provided by an uniaxial birefringent crystal. The coupling between the ordinary and extraordinary eigenstates is shown to depend drastically on the relative positions of the different elements in the cavity, leading to different eigenstates dynamics. Rotation and inhibition vectorial bistability and vectorial simultaneity are successively isolated, the removal of the transversal degeneracy of the two eigenstates allowing a simple eigenstate selection.

  12. Bejel: acquirable only in childhood?

    PubMed

    Rothschild, Bruce M; Rothschild, Christine; Naples, Virginia; Billard, Michel; Panero, Barbara

    2006-10-01

    Bejel clearly has a long history in the Middle East and the Sudan, but was it transmitted to Europe? As the major manifestation of bejel is presence of periosteal reaction in 20-40% of afflicted populations, absence of significant population frequency of periosteal reaction in Europe would exclude that diagnosis. Examination of skeletal populations from continental Europe revealed no significant periosteal reaction at the time of and immediately subsequent to the Crusades. Thus, there is no evidence for bejel in Europe, in spite of clear contact (the mechanism of bejel transmission in children) between warring groups, at least during the Crusades. This supports the hypothesis that bejel is a childhood-acquired disease and apparently cannot be contracted in adulthood.

  13. 7 CFR 926.10 - Acquire.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... REQUIREMENTS APPLICABLE TO CRANBERRIES NOT SUBJECT TO THE CRANBERRY MARKETING ORDER § 926.10 Acquire. Acquire means to obtain cranberries by any means whatsoever for the purpose of handling cranberries....

  14. 7 CFR 926.10 - Acquire.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... REQUIREMENTS APPLICABLE TO CRANBERRIES NOT SUBJECT TO THE CRANBERRY MARKETING ORDER § 926.10 Acquire. Acquire means to obtain cranberries by any means whatsoever for the purpose of handling cranberries....

  15. 7 CFR 926.10 - Acquire.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... REQUIREMENTS APPLICABLE TO CRANBERRIES NOT SUBJECT TO THE CRANBERRY MARKETING ORDER § 926.10 Acquire. Acquire means to obtain cranberries by any means whatsoever for the purpose of handling cranberries....

  16. 7 CFR 926.10 - Acquire.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... REQUIREMENTS APPLICABLE TO CRANBERRIES NOT SUBJECT TO THE CRANBERRY MARKETING ORDER § 926.10 Acquire. Acquire means to obtain cranberries by any means whatsoever for the purpose of handling cranberries....

  17. 7 CFR 926.10 - Acquire.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... REQUIREMENTS APPLICABLE TO CRANBERRIES NOT SUBJECT TO THE CRANBERRY MARKETING ORDER § 926.10 Acquire. Acquire means to obtain cranberries by any means whatsoever for the purpose of handling cranberries....

  18. Acquired haemophilia in recipients of depot thioxanthenes.

    PubMed

    Stewart, A J; Manson, L M; Dasani, H; Beddall, A; Collins, P; Shima, M; Ludlam, C A

    2000-11-01

    We present two cases in which the occurrence of acquired haemophilia is associated with the use of depot preparations of the thioxanthenes zuclopenthixol and flupenthixol. These drugs have not previously been implicated in the aetiology of acquired haemophilia.

  19. Acquiring Evolving Technologies: Web Services Standards

    DTIC Science & Technology

    2016-06-30

    2006 Carnegie Mellon University Acquiring Evolving Technologies : Web Services Standards Harry L. Levinson Software Engineering Institute Carnegie...Acquiring Evolving Technologies : Web Services Standards 5a. CONTRACT NUMBER 5b. GRANT NUMBER 5c. PROGRAM ELEMENT NUMBER 6. AUTHOR(S) 5d. PROJECT...298 (Rev. 8-98) Prescribed by ANSI Std Z39-18 2 Acquiring Evolving Technologies : Web Services Standards © 2006 Carnegie Mellon University Acquiring

  20. RESOLVE and ECO: Survey Design

    NASA Astrophysics Data System (ADS)

    Kannappan, Sheila; Moffett, Amanda J.; Norris, Mark A.; Eckert, Kathleen D.; Stark, David; Berlind, Andreas A.; Snyder, Elaine M.; Norman, Dara J.; Hoversten, Erik A.; RESOLVE Team

    2016-01-01

    The REsolved Spectroscopy Of a Local VolumE (RESOLVE) survey is a volume-limited census of stellar, gas, and dynamical mass as well as star formation and galaxy interactions within >50,000 cubic Mpc of the nearby cosmic web, reaching down to dwarf galaxies of baryonic mass ~10^9 Msun and spanning multiple large-scale filaments, walls, and voids. RESOLVE is surrounded by the ~10x larger Environmental COntext (ECO) catalog, with matched custom photometry and environment metrics enabling analysis of cosmic variance with greater statistical power. For the ~1500 galaxies in its two equatorial footprints, RESOLVE goes beyond ECO in providing (i) deep 21cm data with adaptive sensitivity ensuring HI mass detections or upper limits <10% of the stellar mass and (ii) 3D optical spectroscopy including both high-resolution ionized gas or stellar kinematic data for each galaxy and broad 320-725nm spectroscopy spanning [OII] 3727, Halpha, and Hbeta. RESOLVE is designed to complement other radio and optical surveys in providing diverse, contiguous, and uniform local/global environment data as well as unusually high completeness extending into the gas-dominated dwarf galaxy regime. RESOLVE also offers superb reprocessed photometry including full, deep NUV coverage and synergy with other equatorial surveys as well as unique northern and southern facilities such as Arecibo, the GBT, and ALMA. The RESOLVE and ECO surveys have been supported by funding from NSF grants AST-0955368 and OCI-1156614.

  1. First-principles approach to excitons in time-resolved and angle-resolved photoemission spectra

    NASA Astrophysics Data System (ADS)

    Perfetto, E.; Sangalli, D.; Marini, A.; Stefanucci, G.

    2016-12-01

    In this work we put forward a first-principles approach and propose an accurate diagrammatic approximation to calculate the time-resolved (TR) and angle-resolved photoemission spectrum of systems with excitons. We also derive an alternative formula to the TR photocurrent which involves a single time-integral of the lesser Green's function. The diagrammatic approximation applies to the relaxed regime characterized by the presence of quasistationary excitons and vanishing polarization. The nonequilibrium self-energy diagrams are evaluated using excited Green's functions; since this is not standard, the analytic derivation is presented in detail. The final result is an expression for the lesser Green's function in terms of quantities that can all be calculated in a first-principles manner. The validity of the proposed theory is illustrated in a one-dimensional model system with a direct gap. We discuss possible scenarios and highlight some universal features of the exciton peaks. Our results indicate that the exciton dispersion can be observed in TR and angle-resolved photoemission.

  2. Polarized internal target apparatus

    DOEpatents

    Holt, R.J.

    1984-10-10

    A polarized internal target apparatus with a polarized gas target of improved polarization and density (achieved by mixing target gas atoms with a small amount of alkali metal gas atoms, and passing a high intensity polarized light source into the mixture to cause the alkali metal gas atoms to become polarized which interact in spin exchange collisions with target gas atoms yielding polarized target gas atoms) is described.

  3. Polarized internal target apparatus

    DOEpatents

    Holt, Roy J.

    1986-01-01

    A polarized internal target apparatus with a polarized gas target of improved polarization and density achieved by mixing target gas atoms with a small amount of alkali metal gas atoms, and passing a high intensity polarized light source into the mixture to cause the alkali metal gas atoms to become polarized which interact in spin exchange collisions with target gas atoms yielding polarized target gas atoms.

  4. Polarization in Scattering

    DTIC Science & Technology

    2010-09-01

    we refer to the linear polarization as parallel if the polarization vector is in the scattering plane or perpendicular if the polarization vector is...obvious that the different polarization states can all be represented as linear combinations of any of the independent pairs of polarization states...J.C. (1976) “Improvement of underwater visibility by reduction of backscatter with a circular polarization technique, Applied Optics, 6, 321-330

  5. Corticomotoneuronal function and hyperexcitability in acquired neuromyotonia.

    PubMed

    Vucic, Steve; Cheah, Benjamin C; Yiannikas, Con; Vincent, Angela; Kiernan, Matthew C

    2010-09-01

    Acquired neuromyotonia encompasses a group of inflammatory disorders characterized by symptoms reflecting peripheral nerve hyperexcitability, which may be clinically confused in the early stages with amyotrophic lateral sclerosis. Despite a clear peripheral nerve focus, it remains unclear whether the ectopic activity in acquired neuromyotonia receives a central contribution. To clarify whether cortical hyperexcitability contributes to development of clinical features of acquired neuromyotonia, the present study investigated whether threshold tracking transcranial magnetic stimulation could detect cortical hyperexcitability in acquired neuromyotonia, and whether this technique could differentiate acquired neuromyotonia from amyotrophic lateral sclerosis. Cortical excitability studies were undertaken in 18 patients with acquired neuromyotonia and 104 patients with amyotrophic lateral sclerosis, with results compared to 62 normal controls. Short-interval intracortical inhibition in patients with acquired neuromyotonia was significantly different when compared to patients with amyotrophic lateral sclerosis (averaged short interval intracortical inhibition acquired neuromyotonia 11.3 +/- 1.9%; amyotrophic lateral sclerosis 2.6 +/- 0.9%, P < 0.001). In addition, the motor evoked potential amplitudes (acquired neuromyotonia 21.0 +/- 3.1%; amyotrophic lateral sclerosis 38.1 +/- 2.2%, P < 0.0001), intracortical facilitation (acquired neuromyotonia -0.9 +/- 1.3%; amyotrophic lateral sclerosis -2.3 +/- 0.6%, P < 0.0001), resting motor thresholds (acquired neuromyotonia 62.2 +/- 1.6%; amyotrophic lateral sclerosis 57.2 +/- 0.9%, P < 0.05) and cortical silent period durations (acquired neuromyotonia 212.8 +/- 6.9 ms; amyotrophic lateral sclerosis 181.1 +/- 4.3 ms, P < 0.0001) were significantly different between patients with acquired neuromyotonia and amyotrophic lateral sclerosis. Threshold tracking transcranial magnetic stimulation established corticomotoneuronal integrity

  6. DISCOVERY OF POLARIZED LINE EMISSION IN SN 1006

    SciTech Connect

    Sparks, W. B.; Pringle, J. E.; Long, K. S.; Cracraft, M.; Carswell, R. F.

    2015-12-10

    Laming predicted that the narrow Balmer line core of the ∼3000 km s{sup −1} shock in the SN 1006 remnant would be significantly polarized due to electron and proton impact polarization. Here, based on deep spectrally resolved polarimetry obtained with the European Southern Observatory (ESO)’s Very Large Telescope (VLT), we report the discovery of polarized line emission with a polarization degree of 1.3% and position angle orthogonal to the SNR filament. Correcting for an unpolarized broad line component, the implied narrow line polarization is ≈2.0%, close to the predictions of Laming. The predicted polarization is primarily sensitive to shock velocity and post-shock temperature equilibration. By measuring polarization for the SN 1006 remnant, we validate and enable a new diagnostic that has important applications in a wide variety of astrophysical situations, such as shocks, intense radiation fields, high energy particle streams, and conductive interfaces.

  7. The Polarization Characteristics of Mercury-like Exoplanets

    NASA Astrophysics Data System (ADS)

    Sun, J.; Qu, Z. Q.; Yan, X. L.

    2012-11-01

    This paper aims at studying the polarization characteristics of Mercury-like exoplanets via the polarization phase curve of the unresolved Mercury. We utilize the Bayesian non-linear fitting method to get the photometric phase curve and the polarization phase curve of Mercury. From these two kinds of curves, we obtain the polarization phase curve of the unresolved Mercury. The results from the unresolved polarization phase curve are as follows: first, in the visible light band the magnitude order of the polarization degree is 10^{-12}; second, its maximum value in the case parallel to the scattering plane is comparable to that in the case vertical to the scattering plane, and their corresponding phase angles are changed evidently in comparison with the resolved Mercury case; third, the polarization amplitudes decrease to zero when the phase angle becomes larger than 158°.

  8. Angle-Resolved Polarimetry of Antenna-Mediated Fluorescence

    NASA Astrophysics Data System (ADS)

    Mohtashami, Abbas; Osorio, Clara I.; Koenderink, A. Femius

    2015-11-01

    Optical phase-array antennas can be used to control not only the angular distribution but also the polarization of fluorescence from quantum emitters. The emission pattern of the resulting system is determined by the properties of the antenna, the properties of the emitters, and the strength of the antenna-emitter coupling. Here we show that Fourier polarimetry can be used to characterize these three contributions. To this end, we measure the angle- and Stokes-parameter-resolved emission of bullseye plasmon antennas as well as spiral antennas excited by an ensemble of emitters. We estimate the average antenna-emitter coupling on the basis of the degree of polarization and determine the effect of anisotropy in the intrinsic emitter orientation on polarization of the resulting emission pattern. Our results provide not only new insights into the behavior of bullseye and spiral antennas but also demonstrate the potential of Fourier polarimetry when characterizing antenna-mediated fluorescence.

  9. {lambda}0 Polarization in Exclusive pp Reactions

    SciTech Connect

    Felix, J.

    2006-09-25

    Among all properties of baryons, the polarization they acquire when created from unpolarized p-nucleus collisions is the most recent discovered one; so far, the origin of this polarization remains unexplained in spite of the experimental evidences accumulated in the past thirty years. Up to these days, {lambda}0 is the most studied baryon for polarization, due to it is very easy to produce {lambda}0's at the energies of the principal high energy physics accelerators of the world. This article is a review of the experimental experience accumulated on the polarization of {lambda}0 in unpolarized exclusive pp collisions as function of xF, PT, and M({lambda}0K+) in the past fifteen years here at the Instituto de Fisica, Universidad de Guanajuato, inside Fermilab e690 and Brookhaven National Laboratory e766 collaborations.

  10. Neuronal Polarity: Demarcation, growth and commitment

    PubMed Central

    Cáceres, Alfredo; Ye, Bing; Dotti, Carlos G.

    2012-01-01

    In a biological sense, polarity refers to the extremity of the main axis of an organelle, cell, or organism. In neurons, morphological polarity begins with the appearance of the first neurite from the cell body. In multipolar neurons, a second phase of polarization occurs when a single neurite initiates a phase of rapid growth to become the neuron’s axon, while the others later differentiate as dendrites. Finally, during a third phase, axons and dendrites develop an elaborate architecture, acquiring special morphological and molecular features that commit them to their final identities. Mechanistically, each phase must be preceded by spatial restriction of growth activity. We will review recent work on the mechanisms underlying the polarized growth of neurons. PMID:22726583

  11. Polar Color

    NASA Technical Reports Server (NTRS)

    2004-01-01

    [figure removed for brevity, see original site]

    Released 3 May 2004 This nighttime visible color image was collected on January 1, 2003 during the Northern Summer season near the North Polar Troughs.

    This daytime visible color image was collected on September 4, 2002 during the Northern Spring season in Vastitas Borealis. The THEMIS VIS camera is capable of capturing color images of the martian surface using its five different color filters. In this mode of operation, the spatial resolution and coverage of the image must be reduced to accommodate the additional data volume produced from the use of multiple filters. To make a color image, three of the five filter images (each in grayscale) are selected. Each is contrast enhanced and then converted to a red, green, or blue intensity image. These three images are then combined to produce a full color, single image. Because the THEMIS color filters don't span the full range of colors seen by the human eye, a color THEMIS image does not represent true color. Also, because each single-filter image is contrast enhanced before inclusion in the three-color image, the apparent color variation of the scene is exaggerated. Nevertheless, the color variation that does appear is representative of some change in color, however subtle, in the actual scene. Note that the long edges of THEMIS color images typically contain color artifacts that do not represent surface variation.

    Image information: VIS instrument. Latitude 79, Longitude 346 East (14 West). 19 meter/pixel resolution.

    Note: this THEMIS visual image has not been radiometrically nor geometrically calibrated for this preliminary release. An empirical correction has been performed to remove instrumental effects. A linear shift has been applied in the cross-track and down-track direction to approximate spacecraft and planetary motion. Fully calibrated and geometrically projected images will be released through the Planetary Data System in accordance with

  12. Broadband graphene polarizer

    NASA Astrophysics Data System (ADS)

    Bao, Qiaoliang; Zhang, Han; Wang, Bing; Ni, Zhenhua; Lim, Candy Haley Yi Xuan; Wang, Yu; Tang, Ding Yuan; Loh, Kian Ping

    2011-07-01

    Conventional polarizers can be classified into three main modes of operation: sheet polarizer using anisotropic absorption media, prism polarizer by refraction and Brewster-angle polarizer by reflection. These polarizing components are not easily integrated with photonic circuits. The in-line fibre polarizer, which relies on polarization-selective coupling between the evanescent field and birefringent crystal or metal, is a promising alternative because of its compatibility with most fibre-optic systems. Here, we demonstrate the operation of a broadband fibre polarizer based on graphene, an ultrathin two-dimensional carbon material. The out-coupled light in the telecommunication band shows a strong s-polarization effect with an extinction ratio of 27 dB. Unlike polarizers made from thin metal film, a graphene polarizer can support transverse-electric-mode surface wave propagation due to its linear dispersion of Dirac electrons.

  13. Associative Learning Through Acquired Salience

    PubMed Central

    Treviño, Mario

    2016-01-01

    Most associative learning studies describe the salience of stimuli as a fixed learning-rate parameter. Presumptive saliency signals, however, have also been linked to motivational and attentional processes. An interesting possibility, therefore, is that discriminative stimuli could also acquire salience as they become powerful predictors of outcomes. To explore this idea, we first characterized and extracted the learning curves from mice trained with discriminative images offering varying degrees of structural similarity. Next, we fitted a linear model of associative learning coupled to a series of mathematical representations for stimulus salience. We found that the best prediction, from the set of tested models, was one in which the visual salience depended on stimulus similarity and a non-linear function of the associative strength. Therefore, these analytic results support the idea that the net salience of a stimulus depends both on the items' effective salience and the motivational state of the subject that learns about it. Moreover, this dual salience model can explain why learning about a stimulus not only depends on the effective salience during acquisition but also on the specific learning trajectory that was used to reach this state. Our mathematical description could be instrumental for understanding aberrant salience acquisition under stressful situations and in neuropsychiatric disorders like schizophrenia, obsessive-compulsive disorder, and addiction. PMID:26793078

  14. Inherited or acquired metabolic disorders.

    PubMed

    Eichler, Florian; Ratai, Eva; Carroll, Jason J; Masdeu, Joseph C

    2016-01-01

    This chapter starts with a description of imaging of inherited metabolic disorders, followed by a discussion on imaging of acquired toxic-metabolic disorders of the adult brain. Neuroimaging is crucial for the diagnosis and management of a number of inherited metabolic disorders. Among these, inherited white-matter disorders commonly affect both the nervous system and endocrine organs. Magnetic resonance imaging (MRI) has enabled new classifications of these disorders that have greatly enhanced both our diagnostic ability and our understanding of these complex disorders. Beyond the classic leukodystrophies, we are increasingly recognizing new hereditary leukoencephalopathies such as the hypomyelinating disorders. Conventional imaging can be unrevealing in some metabolic disorders, but proton magnetic resonance spectroscopy (MRS) may be able to directly visualize the metabolic abnormality in certain disorders. Hence, neuroimaging can enhance our understanding of pathogenesis, even in the absence of a pathologic specimen. This review aims to present pathognomonic brain MRI lesion patterns, the diagnostic capacity of proton MRS, and information from clinical and laboratory testing that can aid diagnosis. We demonstrate that applying an advanced neuroimaging approach enhances current diagnostics and management. Additional information on inherited and metabolic disorders of the brain can be found in Chapter 63 in the second volume of this series.

  15. Negative circular polarization as a universal property of quantum dots

    SciTech Connect

    Taylor, Matthew W.; Spencer, Peter; Murray, Ray

    2015-03-23

    This paper shows that negative circular polarization, a spin flip of polarized carriers resulting in emission of opposite helicity, can be observed in undoped, n-doped, and p-doped InAs/GaAs quantum dots. These results contradict the usual interpretation of the effect. We show using power dependent and time resolved spectroscopy that the generation of negative circular polarization correlates with excited state emission. Furthermore, a longer spin lifetime of negatively polarized excitons is observed where emission is largely ground state in character.

  16. Parametric analysis of synthetic aperture radar data acquired over truck garden vegetation

    NASA Technical Reports Server (NTRS)

    Wu, S. T.

    1984-01-01

    An airborne X-band SAR acquired multipolarization and multiflight pass SAR images over a truck garden vegetation area. Based on a variety of land cover and row crop direction variations, the vertical (VV) polarization data contain the highest contrast, while cross polarization contains the least. When the radar flight path is parallel to the row direction, both horizontal (HH) and VV polarization data contain very high return which masks out the specific land cover that forms the row structure. Cross polarization data are not that sensitive to row orientation. The inclusion of like and cross polarization data help delineate special surface features (e.g., row crop against non-row-oriented land cover, very-rough-surface against highly row-oriented surface).

  17. Polarization Sensitive Optical Coherence Tomography

    NASA Astrophysics Data System (ADS)

    Park, B. Hyle; de Boer, Johannes F.

    Optical coherence tomography (OCT) is an interferometric technique capable of noninvasive high-resolution cross-sectional imaging by measuring the intensity of light reflected from within tissue [1]. This results in a noncontact imaging modality that provides images similar in scale and geometry to histology. Just as different stains can be used to enhance the contrast in histology, various extensions of OCT allow for visualization of features not readily apparent in traditional OCT. For example, optical Doppler tomography [2] can enable depth-resolved imaging of flow by observing differences in phase between successive depth scans [3-5]. This chapter will focus on polarization-sensitive OCT (PS-OCT), which utilizes depth-dependent changes in the polarization state of detected light to determine the light-polarization changing properties of a sample [6-11]. These properties, including birefringence, dichroism, and optic axis orientation, can be determined directly by studying the depth evolution of Stokes parameters [7-10, 12-16] or indirectly by using the changing reflected polarization states to first determine Jones or Mueller matrices [11, 17-21]. PS-OCT has been used in a wide variety of applications, including correlating burn depth with a decrease in birefringence [14], measuring the birefringence of the retinal nerve fiber layer [22, 23], and monitoring the onset and progression of caries lesions [24]. In this chapter, a discussion of polarization theory and its application to PS-OCTwill be followed by clinical uses of the technology and will conclude with mentionof more recent work and future directions of PS-OCT.

  18. 17 CFR 210.8-06 - Real estate operations acquired or to be acquired.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 17 Commodity and Securities Exchanges 2 2010-04-01 2010-04-01 false Real estate operations acquired or to be acquired. 210.8-06 Section 210.8-06 Commodity and Securities Exchanges SECURITIES AND... Statements of Smaller Reporting Companies § 210.8-06 Real estate operations acquired or to be acquired....

  19. Acquired immune deficiency syndrome: review.

    PubMed

    Scully, C; Cawson, R A; Porter, S R

    1986-07-19

    Acquired immunodeficiency syndrome (AIDS) is reviewed for dental practitioners, with an emphasis on oral findings; the clinical course, diagnosis, reporting, treatment, prognosis, transmission, and epidemiology are also covered. HIV infection has an incubation period that may be associated with glandular fever, a prodrome called AIDS-Related Complex (ARC) characterized by lymphadenopathy, low fever, weight loss, night sweats, diarrhea, oral candidosis, nonproductive cough and recurrent infections. AIDS is characterized by opportunistic infections. Over 50% present with pneumocystis carinii pneumonia, 21% with Kaposi's sarcoma, and 6% have both. The AIDS virus causes direct neurological symptoms in some cases. Oral candidosis (thrush) in a young male without a local cause such as xerostomia or immune suppression is strongly suggestive of AIDS. Other oral manifestations are severe herpes simplex, varicella-zoster, Epstein-Barr virus, cytomegalovirus, venereal warts, aphthous ulceration, mycobacterial oral ulcers, oral histoplasmosis, sinusitis and osteomyelitis of the jaw. Hairy leukoplakia, usually seen on the lateral border of the tongue, is probably caused by Epstein-Barr virus. Kaposi's sarcoma, an endothelial cell tumor, is characteristic of AIDS, and in 50% of patients is oral or perioral. Cervical lymph node enlargement will be seen in those with ARC as well as AIDS. No guidelines have been issued by the Department of Health and Social Security for dental surgeons in the UK for reporting AIDS cases. Although HIV virions have been isolated from saliva, there are no known incidents of transmission via saliva. HIV is less likely to be transmitted by needle stick injuries than, for example hepatitis B (25% risk), especially if the blood is from a carrier rather than a full blown AIDS case.

  20. Clinicopathological associations of acquired erythroblastopenia

    PubMed Central

    Gunes, Gursel; Malkan, Umit Yavuz; Yasar, Hatime Arzu; Eliacik, Eylem; Haznedaroglu, Ibrahim Celalettin; Demiroglu, Haluk; Sayinalp, Nilgun; Aksu, Salih; Etgul, Sezgin; Aslan, Tuncay; Goker, Hakan; Ozcebe, Osman Ilhami; Buyukasik, Yahya

    2015-01-01

    Introduction: Acquired erythroblastopenia (AE) is a rare clinical situation. It is characterized by the reduction of erythroid precursors in the bone marrow together with the low reticulocyte counts in the peripheral blood. Background: Main secondary causes of AE are drugs, Parvovirus B19 and other infectious reasons, lymphoid and myeloid neoplasia, autoimmune diseases, thymoma and pregnancy. The aim of this study is to assess the frequencies and clinical associations of AE via analyzing 12340 bone marrow samples in a retrospective manner. Material and method: Bone marrow aspirations which were obtained from patients who applied to Hacettepe University Hematology Clinic between 2002 and 2013, were analyzed retrospectively. Results: Thirty four erythroblastopenia cases were found. Patients ranged in age from 16 to 80 years with a median of 38 years. Fifteen patients were men (44%) and nineteen were women (56%). In these patients, detected causes of erythroblastopenia were MDS, idiopathic pure red cell aplasia (PRCA), parvovirus infection, post chemotherapy aplasia, plasma proliferative diseases, copper deficiency due to secondary amyloidosis, fever of unknown origin, hemophagocytic syndrome, enteric fever and legionella pneumonia. We found that between those reasons the most common causes of erythroblastopenia are MDS (17.7%) and idiopathic PRCA (17.7%). Discussion: As a result, erythroblastopenia in the bone marrow may be an early sign of MDS. In those AE cases possibility of being MDS must be kept in mind as it can be mistaken for PRCA. Conclusion: To conclude, in adults MDS without excess blast is one of the most common causes of erythroblastopenia in clinical practice and in case of erythroblastopenia the presence of MDS should be investigated. PMID:26885236

  1. Polarized maser growth

    SciTech Connect

    Melrose, D.B.; Judge, A.C.

    2004-11-01

    A polarized maser is assumed to operate in an anisotropic medium with natural modes polarized differently to the maser. It is shown that when the spatial growth rate and the generalized Faraday rotation rate are comparable, the polarization of the growing radiation is different from those of the maser and medium. In particular, for a lineary polarized maser operating in a medium with linearly polarized natural modes, the growing radiation is partially circularly polarized. This provides a previously unrecognized source of circular polarization that may be relevant to pulsar radio emission.

  2. Crossed elliptical polarization undulator

    SciTech Connect

    Sasaki, Shigemi

    1997-05-01

    The first switching of polarization direction is possible by installing two identical helical undulators in series in a same straight section in a storage ring. By setting each undulator in a circular polarization mode in opposite handedness, one can obtain linearly polarized radiation with any required polarization direction depending on the modulator setting between two undulators. This scheme can be used without any major degradation of polarization degree in any low energy low emittance storage ring.

  3. Polarization-balanced beamsplitter

    DOEpatents

    Decker, Derek E.

    1998-01-01

    A beamsplitter assembly that includes several beamsplitter cubes arranged to define a plurality of polarization-balanced light paths. Each polarization-balanced light path contains one or more balanced pairs of light paths, where each balanced pair of light paths includes either two transmission light paths with orthogonal polarization effects or two reflection light paths with orthogonal polarization effects. The orthogonal pairing of said transmission and reflection light paths cancels polarization effects otherwise caused by beamsplitting.

  4. Polarization-balanced beamsplitter

    DOEpatents

    Decker, D.E.

    1998-02-17

    A beamsplitter assembly is disclosed that includes several beamsplitter cubes arranged to define a plurality of polarization-balanced light paths. Each polarization-balanced light path contains one or more balanced pairs of light paths, where each balanced pair of light paths includes either two transmission light paths with orthogonal polarization effects or two reflection light paths with orthogonal polarization effects. The orthogonal pairing of said transmission and reflection light paths cancels polarization effects otherwise caused by beamsplitting. 10 figs.

  5. Semantic-enabled Spatiotemporal Web Portal for Polar Sciences

    NASA Astrophysics Data System (ADS)

    Liu, K.

    2014-12-01

    It is essential for Intergovernmental and scientists to study, monitor and analyze the geographic data in polar regions. Polarregions are likely to respond rapidly and more severely to the climate changesthan any other area on the Earth.They also have significant importance for Global warming research. The ocean water around the Antarctic and Arctic is a crucial part of the ocean's thermohaline circulation. The Polar Cyberinfrastructure Program was built to acquire, share, access, analyze the polar data for Arctic and Antarctic communities. The polar data are becoming big and bring challenges for Polar Cyberinfrastructure Program including: 1) it is difficultfor polar data users to discover most relevant data based on the understanding the behavior; 2) the quality of polar data service is essential to use the polar data, however, it varies for users in different locations and different time. The semantic enabled discovery and volunteer computing are used in the Polar Cyberinfrastructurefor tackling these challenges: 1) semantic search and knowledge reasoning to improve the discovery recall and precision of polar data; 2) volunteer computing is used to gather volunteers computing resources around the world to improve the quality evaluationaccuracy of polar data service. Keywords: Polar Science, Cyberinfrastructure, Semantic, Volunteer Computing

  6. Propagation of dynamic nuclear polarization across the xenon cluster boundaries: elucidation of the spin-diffusion bottleneck.

    PubMed

    Pourfathi, M; Kuzma, N N; Kara, H; Ghosh, R K; Shaghaghi, H; Kadlecek, S J; Rizi, R R

    2013-10-01

    Earlier Dynamic Nuclear Polarization (DNP) experiments with frozen xenon/1-propanol/trityl mixtures have demonstrated spontaneous formation of pure xenon clusters above 120 K, enabling spectrally-resolved real-time measurements of (129)Xe nuclear magnetization in the clusters and in the surrounding radical-rich matrix. A spin-diffusion bottleneck was postulated to explain the peculiar time evolution of (129)Xe signals in the clusters as well as the apparent discontinuity of (129)Xe polarization across the cluster boundaries. A self-contained ab initio model of nuclear spin diffusion in heterogeneous systems is developed here, incorporating the intrinsic T1 relaxation towards the temperature-dependent equilibrium polarization and the spin-diffusion coefficients based on the measured NMR line widths and the known atomic densities in each compartment. This simple model provides the physical basis for the observed spin-diffusion bottleneck and is in a good quantitative agreement with the earlier measurements. A simultaneous fit of the model to the time-dependent NMR data at two different DNP frequencies provides excellent estimates of the cluster size, the intrinsic sample temperature, and (129)Xe T1 constants. The model was also applied to the NMR data acquired during relaxation towards the thermal equilibrium after the microwaves were turned off, to estimate T1 relaxation time constants inside and outside the clusters. Fitting the model to the data during and after DNP provides consistent estimates of the cluster size.

  7. Numerical study of super-resolved optical microscopy with partly staggered beams

    NASA Astrophysics Data System (ADS)

    He, Jinping; Wang, Nan; Kobayashi, Takayoshi

    2016-12-01

    The resolving power of optical microscopy involving two or even more beams, such as pump-probe microscopy and nonlinear optical microscopy, can be enhanced both laterally and longitudinally with partly staggered beams. A numerical study of the new super-resolution imaging technology is performed with vector diffraction theory. The influence of polarization is discussed. A resolving power of sub-100 nm and sub-300 nm in the lateral and longitudinal directions, respectively, is achievable.

  8. Polar cap precursor of nightside auroral oval intensifications using polar cap arcs

    NASA Astrophysics Data System (ADS)

    Zou, Ying; Nishimura, Yukitoshi; Lyons, Larry R.; Donovan, Eric F.; Shiokawa, Kazuo; Ruohoniemi, J. Michael; McWilliams, Kathryn A.; Nishitani, Nozomu

    2015-12-01

    Recent radar and optical observations suggested that localized fast flows in the polar cap precede disturbances within the nightside auroral oval. However, how commonly this connection occurs has been difficult to examine due to limited coverage of radar flow measurements and diffuse and dim nature of airglow patches. Polar cap arcs are also associated with fast flows in the polar cap and appear much brighter than patches, allowing evaluation of the interaction between polar cap structures and nightside aurora more definitively. We have surveyed data during six winter seasons and selected quasi-steady polar cap arcs lasting >1 h. Thirty-four arcs are found, and for the majority (~85%) of them, as they extend equatorward from high latitude, their contact with the nightside auroral poleward boundary is associated with new and substantial intensifications within the oval. These intensifications are localized (< ~1 h magnetic local time (MLT)) and statistically occur within 10 min and ±1 h MLT from the contact. They appear as poleward boundary intensifications in a thick auroral oval or an intensification of the only resolvable arc within a thin oval, and the latter can also exhibit substantial poleward expansion. When radar echoes are available, they corroborate the association of polar cap arcs with localized enhanced antisunward flows. That the observed oval intensifications are major disturbances that only occur after the impingement of polar cap arcs and near the contact longitude suggest that they are triggered by localized fast flows coming from deep in the polar cap.

  9. Cryptosporidiosis in the acquired immune deficiency syndrome.

    PubMed

    Cooper, D A; Wodak, A; Marriot, D J; Harkness, J L; Ralston, M; Hill, A; Penny, R

    1984-10-01

    Cryptosporidiosis was found in a patient with the acquired immune deficiency syndrome. The microbiological and morphological features of this newly recognized opportunistic infection are distinctive and diagnostic.

  10. Resolvability of positron decay channels

    SciTech Connect

    Fluss, M.J.; Howell, R.H.; Rosenberg, I.J.; Meyer, P.

    1985-03-07

    Many data analysis treatments of positron experiments attempt to resolve two or more positron decay or exist channels which may be open simultaneously. Examples of the need to employ such treatments of the experimental results can be found in the resolution of the constituents of a defect ensemble, or in the analysis of the complex spectra which arise from the interaction of slow positrons at or near the surfaces of solids. Experimental one- and two-dimensional angular correlation of annihilation radiation experiments in Al single crystals have shown that two defect species (mono- and divacancies) can be resolved under suitable conditions. Recent experiments at LLNL indicate that there are a variety of complex exit channels open to positrons interacting at surfaces, and ultimely these decay channels must also be suitably resolved from one another. 6 refs., 4 figs.

  11. Resolving boosted jets with XCone

    NASA Astrophysics Data System (ADS)

    Thaler, Jesse; Wilkason, Thomas F.

    2015-12-01

    We show how the recently proposed XCone jet algorithm [1] smoothly interpolates between resolved and boosted kinematics. When using standard jet algorithms to reconstruct the decays of hadronic resonances like top quarks and Higgs bosons, one typically needs separate analysis strategies to handle the resolved regime of well-separated jets and the boosted regime of fat jets with substructure. XCone, by contrast, is an exclusive cone jet algorithm that always returns a fixed number of jets, so jet regions remain resolved even when (sub)jets are overlapping in the boosted regime. In this paper, we perform three LHC case studies — dijet resonances, Higgs decays to bottom quarks, and all-hadronic top pairs — that demonstrate the physics applications of XCone over a wide kinematic range.

  12. Metasurface polarization splitter.

    PubMed

    Slovick, Brian A; Zhou, You; Yu, Zhi Gang; Kravchenko, Ivan I; Briggs, Dayrl P; Moitra, Parikshit; Krishnamurthy, Srini; Valentine, Jason

    2017-03-28

    Polarization beam splitters, devices that separate the two orthogonal polarizations of light into different propagation directions, are among the most ubiquitous optical elements. However, traditionally polarization splitters rely on bulky optical materials, while emerging optoelectronic and photonic circuits require compact, chip-scale polarization splitters. Here, we show that a rectangular lattice of cylindrical silicon Mie resonators functions as a polarization splitter, efficiently reflecting one polarization while transmitting the other. We show that the polarization splitting arises from the anisotropic permittivity and permeability of the metasurface due to the twofold rotational symmetry of the rectangular unit cell. The high polarization efficiency, low loss and low profile make these metasurface polarization splitters ideally suited for monolithic integration with optoelectronic and photonic circuits.This article is part of the themed issue 'New horizons for nanophotonics'.

  13. Polarized positrons and electrons at the linear collider

    NASA Astrophysics Data System (ADS)

    Moortgat-Pick, G.; Abe, T.; Alexander, G.; Ananthanarayan, B.; Babich, A. A.; Bharadwaj, V.; Barber, D.; Bartl, A.; Brachmann, A.; Chen, S.; Clarke, J.; Clendenin, J. E.; Dainton, J.; Desch, K.; Diehl, M.; Dobos, B.; Dorland, T.; Dreiner, H. K.; Eberl, H.; Ellis, J.; Flöttmann, K.; Fraas, H.; Franco-Sollova, F.; Franke, F.; Freitas, A.; Goodson, J.; Gray, J.; Han, A.; Heinemeyer, S.; Hesselbach, S.; Hirose, T.; Hohenwarter-Sodek, K.; Juste, A.; Kalinowski, J.; Kernreiter, T.; Kittel, O.; Kraml, S.; Langenfeld, U.; Majerotto, W.; Martinez, A.; Martyn, H.-U.; Mikhailichenko, A.; Milstene, C.; Menges, W.; Meyners, N.; Mönig, K.; Moffeit, K.; Moretti, S.; Nachtmann, O.; Nagel, F.; Nakanishi, T.; Nauenberg, U.; Nowak, H.; Omori, T.; Osland, P.; Pankov, A. A.; Paver, N.; Pitthan, R.; Pöschl, R.; Porod, W.; Proulx, J.; Richardson, P.; Riemann, S.; Rindani, S. D.; Rizzo, T. G.; Schälicke, A.; Schüler, P.; Schwanenberger, C.; Scott, D.; Sheppard, J.; Singh, R. K.; Sopczak, A.; Spiesberger, H.; Stahl, A.; Steiner, H.; Wagner, A.; Weber, A. M.; Weiglein, G.; Wilson, G. W.; Woods, M.; Zerwas, P.; Zhang, J.; Zomer, F.

    2008-05-01

    The proposed International Linear Collider (ILC) is well-suited for discovering physics beyond the Standard Model and for precisely unraveling the structure of the underlying physics. The physics return can be maximized by the use of polarized beams. This report shows the paramount role of polarized beams and summarizes the benefits obtained from polarizing the positron beam, as well as the electron beam. The physics case for this option is illustrated explicitly by analyzing reference reactions in different physics scenarios. The results show that positron polarization, combined with the clean experimental environment provided by the linear collider, allows to improve strongly the potential of searches for new particles and the identification of their dynamics, which opens the road to resolve shortcomings of the Standard Model. The report also presents an overview of possible designs for polarizing both beams at the ILC, as well as for measuring their polarization.

  14. Spin polarization of Co(0001)/graphene junctions from first principles.

    PubMed

    Sipahi, G M; Žutić, Igor; Atodiresei, N; Kawakami, R K; Lazić, P

    2014-03-12

    Junctions comprised of ferromagnets and nonmagnetic materials are one of the key building blocks in spintronics. With the recent breakthroughs of spin injection in ferromagnet/graphene junctions it is possible to consider spin-based applications that are not limited to magnetoresistive effects. However, for critical studies of such structures it is crucial to establish accurate predictive methods that would yield atomically resolved information on interfacial properties. By focusing on Co(0001)/graphene junctions and their electronic structure, we illustrate the inequivalence of different spin polarizations. We show atomically resolved spin polarization maps as a useful approach to assess the relevance of Co(0001)/graphene for different spintronics applications.

  15. Polarized reflectance and transmittance properties of windblown sea surfaces.

    PubMed

    Mobley, Curtis D

    2015-05-20

    Generation of random sea surfaces using wave variance spectra and Fourier transforms is formulated in a way that guarantees conservation of wave energy and fully resolves wave height and slope variances. Monte Carlo polarized ray tracing, which accounts for multiple scattering between light rays and wave facets, is used to compute effective Mueller matrices for reflection and transmission of air- or water-incident polarized radiance. Irradiance reflectances computed using a Rayleigh sky radiance distribution, sea surfaces generated with Cox-Munk statistics, and unpolarized ray tracing differ by 10%-18% compared with values computed using elevation- and slope-resolving surfaces and polarized ray tracing. Radiance reflectance factors, as used to estimate water-leaving radiance from measured upwelling and sky radiances, are shown to depend on sky polarization, and improved values are given.

  16. Polarization Properties of Rotation Powered Pulsars

    NASA Technical Reports Server (NTRS)

    Harding Alice K.

    2009-01-01

    Polarization measurements of rotation-powered pulsars and their nebulae have unique diagnostic potential. The polarization position angle of the pulsar wind nebula, as is know for the Crab pulsar, can tell us the orientation of the spin axis. Phase-resolved polarimetry of pulsars has had enormous diagnostic capability at radio and optical wavelengths and could also be a powerful diagnostic in the X-ray range. Measurement of the polarization properties as a function of pulse phase can therefore provide a multidimensional mapping of the pulsar emission. In the 'rotating vector' model, radiation originating near a magnetic pole is expected to show a characteristic S-shaped swing of the position angle vs. pulse phase. In this case it is possible to determine the magnetic inclination and viewing angles. Radiation originating further from the poles or further above the neutron star surface will have a more complex polarization signature, as a result of relativistic effects of aberration and time-of-flight delays and may also cause depolarization of the signal. I will discuss predicted polarization properties of pulsed emission in polar cap models, where radiation originates near the neutron star surface at the magnetic poles, and in slot gap and outer gap models, where radiation originates over a range of altitudes out to the speed-of-light cylinder.

  17. Acquiring and Managing Electronic Journals. ERIC Digest.

    ERIC Educational Resources Information Center

    Curtis, Donnelyn; Yue, Paoshan

    Electronic journals are both a blessing and a curse for libraries. To be meaningful in the current information environment--to meet users' ever-increasing demands--libraries must acquire as many appropriate full text resources as possible, as quickly as possible, and make them easy to use. This Digest provides tips for acquiring and providing…

  18. Acquired idiopathic generalized anhidrosis: case report.

    PubMed

    Brantley, Elise I; Mutasim, Diya F; Heaton, Charles

    2011-01-01

    We report a case of acquired idiopathic generalized anhidrosis (AIGA) in a 56-year-old white woman. Acquired idiopathic generalized anhidrosis is an exceedingly rare group of heterogeneous disorders that has been almost exclusively reported in young Japanese males. Our case is unique in that AlGA may be underrecognized in this patient population.

  19. Global profiles of the direct aerosol effect using vertically resolved aerosol data

    NASA Astrophysics Data System (ADS)

    Korras Carraca, Marios Bruno; Pappas, Vasilios; Matsoukas, Christos; Hatzianastassiou, Nikolaos; Vardavas, Ilias

    2014-05-01

    Atmospheric aerosols, both natural and anthropogenic, can cause climate change through their direct, indirect, and semi-direct effects on the radiative energy budget of the Earth-atmosphere system. In general, aerosols cause cooling of the surface and the planet, while they warm the atmosphere due to scattering and absorption of incoming solar radiation. The importance of vertically resolved direct radiative effect (DRE) and heating/cooling effects of aerosols is strong, while large uncertainties still lie with their magnitudes. In order to be able to quantify them throughout the atmosphere, a detailed vertical profile of the aerosol effect is required. Such data were made available recently by the Cloud-Aerosol Lidar with Orthogonal Polarization (CALIOP) on board the Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observations (CALIPSO) satellite. CALIOP is the first polarization lidar to fly in space and has been acquiring unique data on aerosols and clouds since June 2006. The aim of this study is to investigate both the vertically resolved geographic and seasonal variation of the DRE due to aerosols. The vertical profile of DRE under all-sky and clear-sky conditions is computed using the deterministic spectral radiative transfer model FORTH. From the DRE, the effect on atmospheric heating/cooling rate profiles due to aerosols can also be derived. We use CALIOP Level 2-Version 3 Layer aerosol optical depth data as input to our radiation transfer model, for a period of 3 complete years (2007-2009). These data are provided on a 5 km horizontal resolution and in up to 8 vertical layers and have been regridded on our model horizontal and vertical resolutions. We use cloud data from the International Satellite Cloud Climatology Project (ISCCP), while the aerosol asymmetry factor and single scattering albedo are taken from the Global Aerosol Data Set (GADS). The model computations are performed on a monthly, 2.5°× 2.5° resolution on global scale, at 40

  20. [A review on polarization information in the remote sensing detection].

    PubMed

    Gong, Jie-Qiong; Zhan, Hai-Gang; Liu, Da-Zhao

    2010-04-01

    Polarization is one of the inherent characteristics. Because the surface of the target structure, internal structure, and the angle of incident light are different, the earth's surface and any target in atmosphere under optical interaction process will have their own characteristic nature of polarization. Polarimetric characteristics of radiation energy from the targets are used in polarization remote sensing detection as detective information. Polarization remote sensing detection can get the seven-dimensional information of targets in complicated backgrounds, detect well-resolved outline of targets and low-reflectance region of objectives, and resolve the problems of atmospheric detection and identification camouflage detection which the traditional remote sensing detection can not solve, having good foreground in applications. This paper introduces the development of polarization information in the remote sensing detection from the following four aspects. The rationale of polarization remote sensing detection is the base of polarization remote sensing detection, so it is firstly introduced. Secondly, the present researches on equipments that are used in polarization remote sensing detection are particularly and completely expatiated. Thirdly, the present exploration of theoretical simulation of polarization remote sensing detection is well detailed. Finally, the authors present the applications research home and abroad of the polarization remote sensing detection technique in the fields of remote sensing, atmospheric sounding, sea surface and underwater detection, biology and medical diagnosis, astronomical observation and military, summing up the current problems in polarization remote sensing detection. The development trend of polarization remote sensing detection technology in the future is pointed out in order to provide a reference for similar studies.

  1. Virginia Resolves, 1993-1994.

    ERIC Educational Resources Information Center

    Morrow, S. Rex, Ed.

    1994-01-01

    These two issues of "Virginia Resolves" provide articles of interest to the social studies reader and provides ideas for social studies instruction and curriculum. The fall issue features seven articles: (1) "Death and the Young Child" (Rosanne J. Marek); (2) "Simulations: Bibliography for the Middle and Elementary…

  2. Resolving Ethical Issues at School

    ERIC Educational Resources Information Center

    Benninga, Jacques S.

    2013-01-01

    Although ethical dilemmas are a constant in teachers' lives, the profession has offered little in the way of training to help teachers address such issues. This paper presents a framework, based on developmental theory, for resolving professional ethical dilemmas. The Four-Component Model of Moral Maturity, when used in conjunction with a…

  3. Time-resolved vibrational spectroscopy

    SciTech Connect

    Tokmakoff, Andrei; Champion, Paul; Heilweil, Edwin J.; Nelson, Keith A.; Ziegler, Larry

    2009-05-14

    This document contains the Proceedings from the 14th International Conference on Time-Resolved Vibrational Spectroscopy, which was held in Meredith, NH from May 9-14, 2009. The study of molecular dynamics in chemical reaction and biological processes using time-resolved spectroscopy plays an important role in our understanding of energy conversion, storage, and utilization problems. Fundamental studies of chemical reactivity, molecular rearrangements, and charge transport are broadly supported by the DOE's Office of Science because of their role in the development of alternative energy sources, the understanding of biological energy conversion processes, the efficient utilization of existing energy resources, and the mitigation of reactive intermediates in radiation chemistry. In addition, time-resolved spectroscopy is central to all fiveof DOE's grand challenges for fundamental energy science. The Time-Resolved Vibrational Spectroscopy conference is organized biennially to bring the leaders in this field from around the globe together with young scientists to discuss the most recent scientific and technological advances. The latest technology in ultrafast infrared, Raman, and terahertz spectroscopy and the scientific advances that these methods enable were covered. Particular emphasis was placed on new experimental methods used to probe molecular dynamics in liquids, solids, interfaces, nanostructured materials, and biomolecules.

  4. Polarization maintaining fiber based ultra-high resolution spectral domain polarization sensitive optical coherence tomography

    PubMed Central

    2010-01-01

    We present a new ultra high resolution spectral domain polarization sensitive optical coherence tomography (PS-OCT) system based on polarization maintaining (PM) fibers. The method transfers the principles of our previous bulk optic PS-OCT systems to a fiberized setup. The phase shift between the orthogonal polarization states travelling in the two orthogonal modes of the PM fiber is compensated by software in post processing. Thereby, the main advantage of our bulk optics setups, i.e. the use of only a single input polarization state to simultaneously acquire reflectivity, retardation, optic axis orientation, and Stokes vector, is maintained. The use of a broadband light source of 110 nm bandwidth provides improved depth resolution and smaller speckle size. The latter is important for improved resolution of depolarization imaging. We demonstrate our instrument for high-resolution PS-OCT imaging of the healthy human retina. PMID:20052196

  5. Long Term Changes in the Polar Vortices

    NASA Astrophysics Data System (ADS)

    Braathen, Geir O.

    2016-04-01

    As the amount of halogens in the stratosphere is slowly declining and the ozone layer slowly recovers it is of interest to see how the meteorological conditions in the vortex develop over the long term since such changes might alter the foreseen ozone recovery. In conjunction with the publication of the WMO Antarctic and Arctic Ozone Bulletins, WMO has acquired the ERA Interim global reanalysis data set for several meteorological parameters. This data set goes from 1979 - present. These long time series of data can be used for several useful studies of the long term development of the polar vortices. Several "environmental indicators" for vortex change have been calculated, and a climatology, as well as trends, for these parameters will be presented. These indicators can act as yardsticks and will be useful for understanding past and future changes in the polar vortices and how these changes affect polar ozone depletion. Examples of indicators are: vortex mean temperature, vortex minimum temperature, vortex mean PV, vortex "importance" (PV*area), vortex break-up time, mean and maximum wind speed. Data for both the north and south polar vortices have been analysed at several isentropic levels from 350 to 850 K. A possible link between changes in PV and sudden stratospheric warmings will be investigated, and the results presented. The unusual meteorological conditions of the 2015 south polar vortex and the 2010/11 and 2015/16 north polar vortices will be compared to other recent years.

  6. Time resolved optical tomography of the human forearm

    NASA Astrophysics Data System (ADS)

    Hillman, Elizabeth M. C.; Hebden, Jeremy C.; Schweiger, Martin; Dehghani, Hamid; Schmidt, Florian E. W.; Delpy, David T.; Arridge, Simon R.

    2001-04-01

    A 32-channel time-resolved optical imaging instrument has been developed principally to study functional parameters of the new-born infant brain. As a prelude to studies on infants, the device and image reconstruction methodology have been evaluated on the adult human forearm. Cross-sectional images were generated using time-resolved measurements of transmitted light at two wavelengths. All data were acquired using a fully automated computer-controlled protocol. Images representing the internal scattering and absorbing properties of the arm are presented, as well as images that reveal physiological changes during a simple finger flexion exercise. The results presented in this paper represent the first simultaneous tomographic reconstruction of the internal scattering and absorbing properties of a clinical subject using purely temporal data, with additional co-registered difference images showing repeatable absorption changes at two wavelengths in response to exercise.

  7. Time resolved optical tomography of the human forearm.

    PubMed

    Hillman, E M; Hebden, J C; Schweiger, M; Dehghani, H; Schmidt, F E; Delpy, D T; Arridge, S R

    2001-04-01

    A 32-channel time-resolved optical imaging instrument has been developed principally to study functional parameters of the new-born infant brain. As a prelude to studies on infants, the device and image reconstruction methodology have been evaluated on the adult human forearm. Cross-sectional images were generated using time-resolved measurements of transmitted light at two wavelengths. All data were acquired using a fully automated computer-controlled protocol. Images representing the internal scattering and absorbing properties of the arm are presented, as well as images that reveal physiological changes during a simple finger flexion exercise. The results presented in this paper represent the first simultaneous tomographic reconstruction of the internal scattering and absorbing properties of a clinical subject using purely temporal data, with additional co-registered difference images showing repeatable absorption changes at two wavelengths in response to exercise.

  8. A Translational Polarization Rotator

    NASA Technical Reports Server (NTRS)

    Chuss, David T.; Wollack, Edward J.; Pisano, Giampaolo; Ackiss, Sheridan; U-Yen, Kongpop; Ng, Ming wah

    2012-01-01

    We explore a free-space polarization modulator in which a variable phase introduction between right- and left-handed circular polarization components is used to rotate the linear polarization of the outgoing beam relative to that of the incoming beam. In this device, the polarization states are separated by a circular polarizer that consists of a quarter-wave plate in combination with a wire grid. A movable mirror is positioned behind and parallel to the circular polarizer. As the polarizer-mirror distance is separated, an incident liear polarization will be rotated through an angle that is proportional to the introduced phase delay. We demonstrate a prototype device that modulates Stokes Q and U over a 20% bandwidth.

  9. Polarized Light Corridor Demonstrations.

    ERIC Educational Resources Information Center

    Davies, G. R.

    1990-01-01

    Eleven demonstrations of light polarization are presented. Each includes a brief description of the apparatus and the effect demonstrated. Illustrated are strain patterns, reflection, scattering, the Faraday Effect, interference, double refraction, the polarizing microscope, and optical activity. (CW)

  10. Polarization at SLAC

    SciTech Connect

    Woods, M.

    1995-01-01

    A highly polarized electron beam is a key feature. for the Current physics program at SLAC. An electron beam polarization of 80% can now be routinely achieved for typically 5000 hours of machine operation per year. Two main Physics programs utilize the polarized beam. Fixed target experiments in End Station A study the collision of polarized electrons with polarized nuclear targets to elucidate the spin structure of the nucleon and to provide an important test of QCD. Using the SLAC Linear Collider, collisions of polarized electrons with unpolarized positrons allow precise measurements of parity violation in the Z-fermion couplings and provide a very precise measurement of tile weak mixing angle. This paper discusses polarized beam operation at SLAC, and gives an overview of the polarized physics program.

  11. RESOLVE's Field Demonstration on Mauna Kea, Hawaii 2010

    NASA Technical Reports Server (NTRS)

    Captain, Janine; Quinn, Jacqueline; Moss, Thomas; Weis, Kyle

    2010-01-01

    In cooperation with the Canadian Space Agency, and the Northern Centre for Advanced Technology, Inc., NASA has undertaken the In-Situ Resource Utilization (ISRU) project called RESOLVE (Regolith and Environment Science & Oxygen and Lunar Volatile Extraction). This project is an Earth-based lunar precursor demonstration of a system that could be sent to explore permanently shadowed polar lunar craters, where it would drill into regolith, quantify the volatiles that are present, and extract oxygen by hydrogen reduction of iron oxides. The resulting water could be electrolyzed into oxygen to support exploration and hydrogen, which would be recycled through the process. The RESOLVE chemical processing system was mounted on a Canadian Space Agency mobility chasis and successfully demonstrated on Hawaii's Mauna Kea volcano in February 2010. The RESOLVE unit is the initial prototype of a robotic prospecting mission to the Moon. RESOLVE is designed to go to the poles of the Moon to "ground truth" the form and concentration of the hydrogen/water/hydroxyl that has been seen from orbit (M3, Lunar Prospector and LRO) and to test technologies to extract oxygen from the lunar regolith. RESOLVE has the ability to capture a one-meter core sample of lunar regolith and heat it to determine the volatiles that may be released and then demonstrate the production of oxygen from minerals found in the regolith. The RESOLVE project, which is led by KSC, is a multi-center and multi-organizational effort that includes representatives from KSC, JSC, GRC, the Canadian Space Agency, and the Northern Center for Advanced Technology (NORCAT). This paper details the results obtained from four days of lunar analog testing that included gas chromatograph analysis for volatile components, remote control of chemistry and drilling operations via satalite communications, and real-time water quantification using a novel capacitance measurement technique.

  12. Citizen CATE Experiment and Polar Plume Dynamics

    NASA Astrophysics Data System (ADS)

    Mitchell, Adriana; Penn, Matt; Baer, Robert; Bosh, Robert; Garrison, David; Gelderman, Richard; Hare, Honor; Isberner, Fred; Jensen, Logan; Kovac, Sarah; McKay, Myles; Pierce, Michael; Thompson, Patricia; Ursache, Andrei; Varsik, John R.; Walter, Donald; Watson, Zachary; Young, David; Citizen CATE Team

    2017-01-01

    During the summer of 2017, a total solar eclipse will pass over the continental United States, allowing millions of citizens the opportunity to experience a beautiful celestial event. The Citizen Continental-America Telescopic Eclipse (CATE) Experiment plans to harness the power of these many viewers by using volunteers from sites across the US to observe and record the total solar eclipse. The data acquired from each of these sites will be composed into a continuous 90-minute video, allowing the inner solar corona to be studied for an unprecedented length of time.Observations in Indonesia of the March 2016 total solar eclipse allowed initial testing and analysis of the inner corona polar plume dynamics. Using MATLAB, a routine was developed to identify the polar coronal threads and their angle relative to the radial direction to analyze the field line behavior at the boundary of the polar coronal holes.

  13. The relationship of storm severity to directionally resolved radio emissions

    NASA Technical Reports Server (NTRS)

    Johnson, R. O.; Bushman, M. L.; Sherrill, W. M.

    1980-01-01

    Directionally resolved atmospheric radio frequency emission data were acquired from thunderstorms occurring in the central and southwestern United States. In addition, RF sferic tracking data were obtained from hurricanes and tropical depressions occurring in the Gulf of Mexico. The data were acquired using a crossed baseline phase interferometer operating at a frequency of 2.001 MHz. The received atmospherics were tested for phase linearity across the array, and azimuth/elevation angles of arrival were computed in real time. A histogram analysis of sferic burst count versus azimuth provided lines of bearing to centers of intense electrical activity. Analysis indicates a consistent capability of the phase linear direction finder to detect severe meteorological activity to distances of 2000 km from the receiving site. The technique evidences the ability to discriminate severe storms from nonsevere storms coexistent in large regional scale thunderstorm activity.

  14. Benchtop time-resolved magneto-optical Kerr magnetometer.

    PubMed

    Barman, Anjan; Kimura, T; Otani, Y; Fukuma, Y; Akahane, K; Meguro, S

    2008-12-01

    We present here the construction and application of a compact benchtop time-resolved Kerr magnetometer to measure the magnetization precession in magnetic thin films and lithographically patterned elements. As opposed to very expensive femtosecond lasers this system is built upon a picosecond pulsed injection diode laser and electronic pulse and delay generators. The precession is triggered by the electronic pulses of controlled duration and shape, which is launched onto the sample by a microstrip line. We used polarized optical pulses synchronous to the electronic pulses to measure the magneto-optical Kerr rotation. The system is integrated in a conventional upright microscope configuration with separate illumination, imaging, and magneto-optical probe paths. The system offers high stability, relative ease of alignment, sample changing, and a long range of time delay. We demonstrate the measurements of time-resolved dynamics of a Permalloy microwire and microdot using this system, which showed dynamics at two different time scales.

  15. Resolving fundamental limits of adhesive bonding in microfabrication.

    SciTech Connect

    Hall, Jessica S.; Frischknecht, Amalie Lucile; Emerson, John Allen; Adkins, Douglas Ray; Kent, Michael Stuart; Read, Douglas H.; Giunta, Rachel Knudsen; Lamppa, Kerry P.; Kawaguchi, Stacie; Holmes, Melissa A.

    2004-04-01

    As electronic and optical components reach the micro- and nanoscales, efficient assembly and packaging require the use of adhesive bonds. This work focuses on resolving several fundamental issues in the transition from macro- to micro- to nanobonding. A primary issue is that, as bondline thicknesses decrease, knowledge of the stability and dewetting dynamics of thin adhesive films is important to obtain robust, void-free adhesive bonds. While researchers have studied dewetting dynamics of thin films of model, non-polar polymers, little experimental work has been done regarding dewetting dynamics of thin adhesive films, which exhibit much more complex behaviors. In this work, the areas of dispensing small volumes of viscous materials, capillary fluid flow, surface energetics, and wetting have all been investigated. By resolving these adhesive-bonding issues, we are allowing significantly smaller devices to be designed and fabricated. Simultaneously, we are increasing the manufacturability and reliability of these devices.

  16. Calculation of polarization effects

    SciTech Connect

    Chao, A.W.

    1983-09-01

    Basically there are two areas of accelerator applications that involve beam polarization. One is the acceleration of a polarized beam (most likely a proton beam) in a synchrotron. Another concerns polarized beams in an electron storage ring. In both areas, numerical techniques have been very useful.

  17. Partial polarizer filter

    NASA Technical Reports Server (NTRS)

    Title, A. M. (Inventor)

    1978-01-01

    A birefringent filter module comprises, in seriatum. (1) an entrance polarizer, (2) a first birefringent crystal responsive to optical energy exiting the entrance polarizer, (3) a partial polarizer responsive to optical energy exiting the first polarizer, (4) a second birefringent crystal responsive to optical energy exiting the partial polarizer, and (5) an exit polarizer. The first and second birefringent crystals have fast axes disposed + or -45 deg from the high transmitivity direction of the partial polarizer. Preferably, the second crystal has a length 1/2 that of the first crystal and the high transmitivity direction of the partial polarizer is nine times as great as the low transmitivity direction. To provide tuning, the polarizations of the energy entering the first crystal and leaving the second crystal are varied by either rotating the entrance and exit polarizers, or by sandwiching the entrance and exit polarizers between pairs of half wave plates that are rotated relative to the polarizers. A plurality of the filter modules may be cascaded.

  18. Playing with Polarizers.

    ERIC Educational Resources Information Center

    Hecht, Jeff

    1991-01-01

    Discussed is how polarized sunglasses block glare, help spot subtle differences in surfaces, and give a clearer view under water. Information on unpolarized and polarized light is provided. The reasons causing glare to occur and how polarizers decrease glare are discussed. (KR)

  19. Silicon Raman polarizer.

    PubMed

    Kozlov, Victor V; Wabnitz, Stefan

    2012-02-15

    We theoretically investigate the polarization properties of Raman amplifiers based on silicon-on-insulator waveguides, and show that it is possible to realize a waveguide Raman polarizer. The Raman polarizer is a special type of Raman amplifier with the property of producing an amplified and highly repolarized beam when it is fed by a relatively weak and unpolarized signal.

  20. Graphing Polar Curves

    ERIC Educational Resources Information Center

    Lawes, Jonathan F.

    2013-01-01

    Graphing polar curves typically involves a combination of three traditional techniques, all of which can be time-consuming and tedious. However, an alternative method--graphing the polar function on a rectangular plane--simplifies graphing, increases student understanding of the polar coordinate system, and reinforces graphing techniques learned…

  1. Physics with Polarized Nuclei.

    ERIC Educational Resources Information Center

    Thompson, William J.; Clegg, Thomas B.

    1979-01-01

    Discusses recent advances in polarization techniques, specifically those dealing with polarization of atomic nuclei, and how polarized beams and targets are produced. These techniques have greatly increased the scope of possible studies, and provided the tools for testing fundamental symmetries and the spin dependence of nuclear forces. (GA)

  2. Polar Ozone Workshop. Abstracts

    NASA Technical Reports Server (NTRS)

    Aikin, Arthur C.

    1988-01-01

    Results of the proceedings of the Polar Ozone Workshop held in Snowmass, CO, on May 9 to 13, 1988 are given. Topics covered include ozone depletion, ozonometry, polar meteorology, polar stratospheric clouds, remote sensing of trace gases, atmospheric chemistry and dynamical simulations.

  3. Polarity at Many Levels

    ERIC Educational Resources Information Center

    Flannery, Maura C.

    2004-01-01

    An attempt is made to find how polarity arises and is maintained, which is a central issue in development. It is a fundamental attribute of living things and cellular polarity is also important in the development of multicellular organisms and controversial new work indicates that polarization in mammals may occur much earlier than previously…

  4. Polarization feedback laser stabilization

    DOEpatents

    Esherick, Peter; Owyoung, Adelbert

    1988-01-01

    A system for locking two Nd:YAG laser oscillators includes an optical path for feeding the output of one laser into the other with different polarizations. Elliptical polarization is incorporated into the optical path so that the change in polarization that occurs when the frequencies coincide may be detected to provide a feedback signal to control one laser relative to the other.

  5. Activation Layer Stabilization of High Polarization Photocathodes in Sub-Optimal RF Gun Environments

    SciTech Connect

    Gregory A. Mulhollan

    2010-11-16

    Specific activation recipes for bulk, 100 nm thick MBE grown and high polarization III-V photocathode material have been developed which mitigate the effects of exposure to background gasses. Lifetime data using four representative gasses were acquired for bulk GaAs, 100 nm unstrained GaAs and strained superlattice GaAs/GaAsP, all activated both with Cs and then Cs and Li (bi-alkali). Each photoemitter showed marked resilience improvement when activated using the bi-alkali recipe compared to the standard single alkali recipe. A dual alkali activation system at SLAC was constructed, baked and commissioned with the purpose of performing spin-polarization measurements on electrons emitted from the bi-alkali activated surfaces. An end station at SSRL was configured with the required sources for energy resolved photoemission measurements on the bi-alkali activated and CO2 dosed surfaces. The bi-alkali recipes were successfully implemented at SLAC/SSRL. Measurements at SLAC of the photoelectron spin-polarization from the modified activation surface showed no sign of a change in value compared to the standard activated material, i.e., no ill effects. Analysis of photoemission data indicates that the addition of Li to the activation layer results in a multi-layer structure. The presence of Li in the activation layer also acts as an inhibitor to CO2 absorption, hence better lifetimes in worse vacuum were achieved. The bi-alkali activation has been tested on O2 activated GaAs for comparison with NF3 activated surfaces. Comparable resilience to CO2 exposure was achieved for the O2 activated surface. An RF PECVD amorphous silicon growth system was modified to allow high temperature heat cleaning of GaAs substrates prior to film deposition. Growth versus thickness data were collected. Very thin amorphous silicon germanium layers were optimized to exhibit good behavior as an electron emitter. Growth of the amorphous silicon germanium films on the above substrates was fine tuned

  6. Peach maturity/quality assessment using hyperspectral imaging-based spatially-resolved technique

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The objective of this research was to measure the absorption and reduced scattering coefficients of peaches, using a hyperspectral imaging-based spatially-resolved method, for their maturity/quality assessment. A newly developed optical property measuring instrument was used for acquiring hyperspect...

  7. Linear Polarization Measurements of Chromospheric Emission Lines

    NASA Technical Reports Server (NTRS)

    Sheeley, N. R., Jr.; Keller, C. U.

    2003-01-01

    We have used the Zurich Imaging Stokes Polarimeter (ZIMPOL I) with the McMath-Pierce 1.5 m main telescope on Kitt Peak to obtain linear polarization measurements of the off-limb chromosphere with a sensitivity better than 1 x 10(exp -5). We found that the off-disk observations require a combination of good seeing (to show the emission lines) and a clean heliostat (to avoid contamination by scattered light from the Sun's disk). When these conditions were met, we obtained the following principal results: 1. Sometimes self-reversed emission lines of neutral and singly ionized metals showed linear polarization caused by the transverse Zeeman effect or by instrumental cross talk from the longitudinal Zeeman effect in chromospheric magnetic fields. Otherwise, these lines tended to depolarize the scattered continuum radiation by amounts that ranged up to 0.2%. 2. Lines previously known to show scattering polarization just inside the limb (such as the Na I lambda5889 D2 and the He I lambda5876 D3 lines) showed even more polarization above the Sun's limb, with values approaching 0.7%. 3. The O I triplet at lambda7772, lambda7774, and lambda7775 showed a range of polarizations. The lambda7775 line, whose maximum intrinsic polarizability, P(sub max), is less than 1%, revealed mainly Zeeman contributions from chromospheric magnetic fields. However, the more sensitive lambda7772 (P(sub max) = 19%) and lambda7774 (P(sub max) = 29%) lines had relatively strong scattering polarizations of approximately 0.3% in addition to their Zeeman polarizations. At times of good seeing, the polarization spectra resolve into fine structures that seem to be chromospheric spicules.

  8. Spin-Resolved Photoemission of Surface States of W(110)-(1×1)H

    NASA Astrophysics Data System (ADS)

    Hochstrasser, M.; Tobin, J. G.; Rotenberg, Eli; Kevan, S. D.

    2002-11-01

    The surface electronic states of W(110)-(1×1)H have been measured using spin- and angle-resolved photoemission. We directly demonstrate that the surface bands are both split and spin-polarized by the spin-orbit interaction in association with the loss of inversion symmetry near a surface. We observe 100% spin polarization of the surface states, with the spins aligned in the plane of the surface and oriented in a circular fashion relative to the S¯ symmetry point. In contrast, no measurable polarization of nearby bulk states is observed.

  9. HST observations of the limb polarization of Titan

    NASA Astrophysics Data System (ADS)

    Bazzon, A.; Schmid, H. M.; Buenzli, E.

    2014-12-01

    Context. Titan is an excellent test case for detailed studies of the scattering polarization from thick hazy atmospheres. Accurate scattering and polarization parameters have been provided by the in situ measurements of the Cassini-Huygens landing probe. For Earth-bound observations Titan can only be observed at a backscattering situation, where the disk-integrated polarization is close to zero. However, with resolved imaging polarimetry a second order polarization signal along the entire limb of Titan can be measured. Aims: We present the first limb polarization measurements of Titan, which are compared as a test to our limb polarization models. Methods: Previously unpublished imaging polarimetry from the HST archive is presented, which resolves the disk of Titan. We determine flux-weighted averages of the limb polarization and radial limb polarization profiles, and investigate the degradation and cancelation effects in the polarization signal due to the limited spatial resolution of our observations. Taking this into account we derive corrected values for the limb polarization in Titan. The results are compared with limb polarization models, using atmosphere and haze scattering parameters from the literature. Results: In the wavelength bands between 250 nm and 2 μm a strong limb polarization of about 2 - 7% is detected with a position angle perpendicular to the limb. The fractional polarization is highest around 1 μm. As a first approximation, the polarization seems to be equally strong along the entire limb. The comparison of our data with model calculations and the literature shows that the detected polarization is compatible with expectations from previous polarimetric observations taken with Voyager 2, Pioneer 11, and the Huygens probe. Conclusions: Our results indicate that ground-based monitoring measurements of the limb-polarization of Titan could be useful for investigating local haze properties and the impact of short-term and seasonal variations of

  10. Resolving Phase Ambiguities In OQPSK

    NASA Technical Reports Server (NTRS)

    Nguyen, Tien M.

    1991-01-01

    Improved design for modulator and demodulator in offset-quaternary-phase-key-shifting (OQPSK) communication system enables receiver to resolve ambiguity in estimated phase of received signal. Features include unique-code-word modulation and detection and digital implementation of Costas loop in carrier-recovery subsystem. Enchances performance of carrier-recovery subsystem, reduces complexity of receiver by removing redundant circuits from previous design, and eliminates dependence of timing in receiver upon parallel-to-serial-conversion clock.

  11. Resolved conifolds in supergravity solutions

    SciTech Connect

    Ghezelbash, A. M.

    2008-01-15

    We construct generalized 11D supergravity solutions of fully localized intersecting D2/D4 brane systems. These solutions are obtained by embedding six-dimensional resolved Eguchi-Hanson conifolds lifted to M-theory. We reduce these solutions to ten dimensions, obtaining new D-brane systems in type IIA supergravity. We discuss the limits in which the dynamics of the D2 brane decouples from the bulk for these solutions.

  12. A new method for acquiring the complex hologram in optical scanning holography

    NASA Astrophysics Data System (ADS)

    Zhu, Meijuan; Dai, Enwen; Liu, Liren; Sun, Jianfeng; Wu, Yapeng; Zhou, Yu; Yan, Aimin; Zhi, Yanan

    2011-09-01

    In this paper, we propose a new method that can acquire the complex hologram of a 3D object for optical scanning holography (OSH) by using polarized optical elements and a 90 degrees 2×4 optical hybrid. The 3D object is scanned by a wave front combined by a plane and spherical wave with orthogonal polarization. The transmitted/reflected signal light is divided into two beams by a polarized beamsplitter (PBS). Then after the polarization control, the two separated beams are heterodyne detected by a 90 degrees 2×4 optical hybrid with two balanced detectors. The 3D object can be reconstructed from the complex hologram acquired from the balanced detectors. Compared with the conventional OSH, the acousto-optic modulator and complex electronic system are not needed in this method. Another advantage of this method lies in its high efficiency since there is almost no energy loss in the generation of the scanning beam by using the polarized optical elements. This method should be used for 3D holographic microscopy and 3D holographic television.

  13. Optical Control of Spin Polarization in Monolayer Transition Metal Dichalcogenides.

    PubMed

    Chen, Xi; Yan, Tengfei; Zhu, Bairen; Yang, Siyuan; Cui, Xiaodong

    2017-02-28

    Optical excitation could generate electrons' spin polarization in some semiconductors with the control of the field polarization. In this article, we report a series of spin-resolved photocurrent experiments on monolayer tungsten disulfide. The experiments demonstrate that the optical excitations with the same helicity could generate opposite spin polarization around the Fermi level by tuning the excitation energy. The mechanism lies in the valley-dependent optical selection rules, the giant spin-orbit coupling, and spin-valley locking in monolayer transition metal dichalcogenides (TMDs). These exotic features make monolayer TMDs promising candidates for conceptual semiconductor-based spintronics.

  14. Polarization-coupled polariton pairs in a birefringent microcavity

    NASA Astrophysics Data System (ADS)

    Wang, Yinglei; Hu, Tao; Xie, Wei; Sun, Liaoxin; Zhang, Long; Wang, Jian; Gu, Jie; Wu, Lin; Wang, Jun; Shen, Xuechu; Chen, Zhanghai

    2015-03-01

    We demonstrate a clear anticrossing between two polarization-orthogonal exciton-polariton modes in ZnO microwires. The strong coupling between exciton polaritons with orthogonal polarization is evidenced by using angle-resolved photoluminescence spectroscopy. The evolution of the coupling strength with the detuning between the two coupled polariton modes is studied by scanning the excitation spot on a tapered ZnO microwire. Steady oscillations are established between the two differently polarized polariton modes with resonant wave vectors and frequencies, which is well described by the plane wave coupling model.

  15. The Physics of Polarization

    NASA Astrophysics Data System (ADS)

    Landi Degl'Innocenti, Egidio

    2015-10-01

    The introductory lecture that has been delivered at this Symposium is a condensed version of an extended course held by the author at the XII Canary Island Winter School from November 13 to November 21, 2000. The full series of lectures can be found in Landi Degl'Innocenti (2002). The original reference is organized in 20 Sections that are here itemized: 1. Introduction, 2. Description of polarized radiation, 3. Polarization and optical devices: Jones calculus and Muller matrices, 4. The Fresnel equations, 5. Dichroism and anomalous dispersion, 6. Polarization in everyday life, 7. Polarization due to radiating charges, 8. The linear antenna, 9. Thomson scattering, 10. Rayleigh scattering, 11. A digression on Mie scattering, 12. Bremsstrahlung radiation, 13. Cyclotron radiation, 14. Synchrotron radiation, 15. Polarization in spectral lines, 16. Density matrix and atomic polarization, 17. Radiative transfer and statistical equilibrium equations, 18. The amplification condition in polarized radiative transfer, and 19. Coupling radiative transfer and statistical equilibrium equations.

  16. Polarization effects. Volume 2

    SciTech Connect

    Courant, E.

    1981-01-01

    The use of polarized proton beams in ISABELLE is important for several general reasons: (1) With a single longitudinally polarized proton beam, effects involving parity violation can be identified and hence processes involving weak interactions can be separated from those involving strong and electromagnetic interactions. (2) Spin effects are important in the strong interactions and can be useful for testing QCD. The technique for obtaining polarized proton beams in ISABELLE appears promising, particularly in view of the present development of a polarized proton beam for the AGS. Projections for the luminosity in ISABELLE for collisions of polarized protons - one or both beams polarized with longitudinal or transverse polarization - range from 1/100 to 1 times the luminosity for unpolarized protons.

  17. Circular Polarization in AGNs: Polarity and Spectra

    NASA Astrophysics Data System (ADS)

    Aller, M. F.; Aller, H. D.; Plotkin, R. M.

    2005-12-01

    Circular polarization (Stokes V) observations potentially provide information on the nature and origin of the underlying magnetic fields in AGNs. We have been systematically monitoring a group of sources with detectable circular polarization (V>0.1 percent, a level set by the instrumental polarization of our system) in all 4 Stokes parameters at 8.0 and 4.8 GHz since 2000, and also at 14.5 GHz since November 2003, with the University of Michigan prime focus paraboloid antenna. These data are compared with historical observations obtained with the same instrument at 8.0 and 4.8 GHz extending back to 1978. Specific goals are to study the temporal spectral behavior of Stokes V and its relation to variability in total flux and linear polarization, and to investigate the question of polarity stability on decade-long time scales using data obtained with the same instrumentation and at the same frequencies. The data are consistent with linear-to-circular mode conversion in partially opaque regions of the source. We find examples of polarity changes with time at one or more frequencies associated with outbursts in total flux and linear polarization, and polarity differences within the 3 frequencies at a single epoch in one case, 3C 279. Such behavior argues against the notion that the sign of Stokes V is a simple tracer of the net flow of magnetic energy from the central engine to the jet or an indicator of the direction of rotation of the spinning central black hole/accretion disk via the winding up of the initial seed magnetic field. This work was supported in part by NSF grant AST-0307629 and by funds from the University of Michigan.

  18. Polarimetric imaging and retrieval of target polarization characteristics in underwater environment.

    PubMed

    Gu, Yalong; Carrizo, Carlos; Gilerson, Alexander A; Brady, Parrish C; Cummings, Molly E; Twardowski, Michael S; Sullivan, James M; Ibrahim, Amir I; Kattawar, George W

    2016-01-20

    Polarized light fields contain more information than simple irradiance and such capabilities provide an advanced tool for underwater imaging. The concept of the beam spread function (BSF) for analysis of scalar underwater imaging was extended to a polarized BSF which considers polarization. The following studies of the polarized BSF in an underwater environment through Monte Carlo simulations and experiments led to a simplified underwater polarimetric imaging model. With the knowledge acquired in the analysis of the polarimetric imaging formation process of a manmade underwater target with known polarization properties, a method to extract the inherent optical properties of the water and to retrieve polarization characteristics of the target was explored. The proposed method for retrieval of underwater target polarization characteristics should contribute to future efforts to reveal the underlying mechanism of polarization camouflage possessed by marine animals and finally to generalize guidelines for creating engineered surfaces capable of similar polarization camouflage abilities in an underwater environment.

  19. Spatio-Temporal Dynamics of Cross Polarized Wave Generation

    NASA Astrophysics Data System (ADS)

    Adams, Daniel; Squier, Jeff; Durfee, Charles

    2009-10-01

    We use time-domain Spatially and Spectrally Resolved Interferometry (SSRI) to investigate cross-polarized wave (XPW) generation in barium fluoride. We find that the XPW pulse is √3 smaller than the input in the spatiotemporal domain regardless of the input chirp. Additionally, we calculate a temporally dependent focal length resulting from the nonlinear interaction, and discuss its implications.

  20. Specular, diffuse and polarized imagery of an oat canopy

    NASA Technical Reports Server (NTRS)

    Vanderbilt, Vern C.; De Venecia, Kurt J.

    1988-01-01

    Light, polarized by specular reflection, has been found to be an important part of the light scattered by several measured plant canopies. The authors investigate for one canopy the relative importance of specularly reflected sunlight, specularly reflected light from other sources including skylight, and diffusely upwelling light. Polarization images are used to gain increased understanding of the radiation transfer process in a plant canopy. Analysis of the results suggests that properly analyzed polarized remotely sensed data, acquired under specific atmospheric conditions by a specially designed sensor, potentially provide measures of physiological and morphological states of plants in a canopy.

  1. Polarized Solid State Target

    NASA Astrophysics Data System (ADS)

    Dutz, Hartmut; Goertz, Stefan; Meyer, Werner

    2017-01-01

    The polarized solid state target is an indispensable experimental tool to study single and double polarization observables at low intensity particle beams like tagged photons. It was one of the major components of the Crystal-Barrel experiment at ELSA. Besides the operation of the 'CB frozen spin target' within the experimental program of the Crystal-Barrel collaboration both collaborative groups of the D1 project, the polarized target group of the Ruhr Universität Bochum and the Bonn polarized target group, have made significant developments in the field of polarized targets within the CRC16. The Bonn polarized target group has focused its work on the development of technically challenging polarized solid target systems towards the so called '4π continuous mode polarized target' to operate them in combination with 4π-particle detection systems. In parallel, the Bochum group has developed various highly polarized deuterated target materials and high precision NMR-systems, in the meantime used for polarization experiments at CERN, JLAB and MAMI, too.

  2. Statistical Polarization Mode Dispersion/Polarization Dependent Loss Emulator for Polarization Division Multiplexing Transmission Testing

    NASA Astrophysics Data System (ADS)

    Perlicki, Krzysztof

    2010-03-01

    A low-cost statistical polarization mode dispersion/polarization dependent loss emulator is presented in this article. The emulator was constructed by concatenating 15 highly birefringence optical-fiber segments and randomly varying the mode coupling between them by rotating the polarization state. The impact of polarization effects on polarization division multiplexing transmission quality was measured. The designed polarization mode dispersion/polarization dependent loss emulator was applied to mimic the polarization effects of real optical-fiber links.

  3. Near Real-Time Prospecting for Lunar Volatiles: Demonstrating RESOLVE Science in the Field

    NASA Astrophysics Data System (ADS)

    Elphic, R. C.; Colaprete, A.; Heldmann, J. L.; Mattes, G.; Ennico, K.; Sanders, G. B.; Quinn, J.; Fritzler, E.; Marinova, M.; Roush, T. L.; Stoker, C.; Larson, W.; Picard, M.; McMurray, R.; Morse, S.

    2012-12-01

    The Regolith and Environment Science and Oxygen & Lunar Volatile Extraction (RESOLVE) project aims to demonstrate the utility of "in situ resource utilization". In situ resource utilization (ISRU) is a way to rebalance the economics of spaceflight by reducing or eliminating materials that must be brought up from Earth and placed on the surface of the Moon for human use. RESOLVE is developing a rover-borne payload that (1) can locate near subsurface volatiles, (2) excavate and analyze samples of the volatile-bearing regolith, and (3) demonstrate the form, extractability and usefulness of the materials. Such investigations are important not only for ISRU but are also critically important for understanding the scientific nature of these intriguing lunar polar volatile deposits. Temperature models and orbital data suggest near surface volatile concentrations may exist at briefly lit lunar polar locations outside persistently shadowed regions. A lunar rover could be remotely operated at some of these locations for the 4-7 days of expected sunlight at relatively low cost. In July 2012 the RESOLVE project conducted a full-scale field demonstration. In particular, the ability to perform the real-time measurement analysis necessary to search for volatiles and the ability to combine the various measurement techniques to meet the mission measurement and science goals. With help from the Pacific International Space Center for Exploration Systems (PISCES), a lunar rover prototype (provided by the Canadian Space Agency) was equipped with prospecting instruments (neutron spectrometer and near-infrared spectrometer), subsurface access and sampling tools, including both an auger and coring drill (provided by CSA) and subsurface sample analysis instrumentation, including a sample oven system, the Oxygen and Volatile Extraction Node (OVEN), and Gas Chromatograph / Mass Spectrometer system, the Lunar Advanced Volatile Analysis (LAVA) system. Given the relatively short time period this

  4. Near Real Time Prospecting for Lunar Volatiles: Demonstrating RESOLVE Science in the Field

    NASA Technical Reports Server (NTRS)

    Elphic, Richard; Colaprete, Anthony; Heldmann, Jennifer; Mattes, Gregory W.; Ennico, Kimberly; Sanders, Gerald; Quinn, Jacqueline; Tegnerud, Erin Leigh; Marinova, Margarita; Larson, William E.; Picard, Martin; Morse, Stephanie

    2012-01-01

    The Regolith and Environment Science and Oxygen & Lunar Volatile Extraction (RESOLVE) project aims to demonstrate the utility of "in situ resource utilization". In situ resource utilization (ISRU) is a way to rebalance the economics of spaceflight by reducing or eliminating materials that must be brought up from Earth and placed on the surface of the Moon for human use. RESOLVE is developing a rover-borne payload that (1) can locate near subsurface volatiles, (2) excavate and analyze samples of the volatile-bearing regolith, and (3) demonstrate the form, extractability and usefulness of the materials. Such investigations are important not only for ISRU but are also critically important for understanding the scientific nature of these intriguing lunar polar volatile deposits. Temperature models and orbital data suggest near surface volatile concentrations may exist at briefly lit lunar polar locations outside persistently shadowed regions. A lunar rover could be remotely operated at some of these locations for the 4-7 days of expected sunlight at relatively low cost. In July 2012 the RESOLVE project conducted a full-scale field demonstration. In particular, the ability to perform the real-time measurement analysis necessary to search for volatiles and the ability to combine the various measurement techniques to meet the mission measurement and science goals. With help from the Pacific International Space Center for Exploration Systems (PISCES), a lunar rover prototype (provided by the Canadian Space Agency) was equipped with prospecting instruments (neutron spectrometer and near-infrared spectrometer), subsurface access and sampling tools, including both an auger and coring drill (provided by CSA) and subsurface sample analysis instrumentation, including a sample oven system, the Oxygen and Volatile Extraction Node (OVEN), and Gas Chromatograph / Mass Spectrometer system, the Lunar Advanced Volatile Analysis (LAVA) system. Given the relatively short time period this

  5. A Bionic Polarization Navigation Sensor and Its Calibration Method

    PubMed Central

    Zhao, Huijie; Xu, Wujian

    2016-01-01

    The polarization patterns of skylight which arise due to the scattering of sunlight in the atmosphere can be used by many insects for deriving compass information. Inspired by insects’ polarized light compass, scientists have developed a new kind of navigation method. One of the key techniques in this method is the polarimetric sensor which is used to acquire direction information from skylight. In this paper, a polarization navigation sensor is proposed which imitates the working principles of the polarization vision systems of insects. We introduce the optical design and mathematical model of the sensor. In addition, a calibration method based on variable substitution and non-linear curve fitting is proposed. The results obtained from the outdoor experiments provide support for the feasibility and precision of the sensor. The sensor’s signal processing can be well described using our mathematical model. A relatively high degree of accuracy in polarization measurement can be obtained without any error compensation. PMID:27527171

  6. [Review] Polarization and Polarimetry

    NASA Astrophysics Data System (ADS)

    Trippe, Sascha

    2014-02-01

    Polarization is a basic property of light and is fundamentally linked to the internal geometry of a source of radiation. Polarimetry complements photometric, spectroscopic, and imaging analyses of sources of radiation and has made possible multiple astrophysical discoveries. In this article I review (i) the physical basics of polarization: electromagnetic waves, photons, and parameterizations; (ii) astrophysical sources of polarization: scattering, synchrotron radiation, active media, and the Zeeman, Goldreich-Kylafis, and Hanle effects, as well as interactions between polarization and matter (like birefringence, Faraday rotation, or the Chandrasekhar-Fermi effect); (iii) observational methodology: on-sky geometry, influence of atmosphere and instrumental polarization, polarization statistics, and observational techniques for radio, optical, and X/γ wavelengths; and (iv) science cases for astronomical polarimetry: solar and stellar physics, planetary system bodies, interstellar matter, astrobiology, astronomical masers, pulsars, galactic magnetic fields, gamma-ray bursts, active galactic nuclei, and cosmic microwave background radiation.

  7. Automatic Bayesian polarity determination

    NASA Astrophysics Data System (ADS)

    Pugh, D. J.; White, R. S.; Christie, P. A. F.

    2016-07-01

    The polarity of the first motion of a seismic signal from an earthquake is an important constraint in earthquake source inversion. Microseismic events often have low signal-to-noise ratios, which may lead to difficulties estimating the correct first-motion polarities of the arrivals. This paper describes a probabilistic approach to polarity picking that can be both automated and combined with manual picking. This approach includes a quantitative estimate of the uncertainty of the polarity, improving calculation of the polarity probability density function for source inversion. It is sufficiently fast to be incorporated into an automatic processing workflow. When used in source inversion, the results are consistent with those from manual observations. In some cases, they produce a clearer constraint on the range of high-probability source mechanisms, and are better constrained than source mechanisms determined using a uniform probability of an incorrect polarity pick.

  8. A dual polarized antenna system using a meanderline polarizer

    NASA Technical Reports Server (NTRS)

    Burger, H. A.

    1978-01-01

    Certain applications of synthetic aperture radars (e.g., aerial crop surveying) require transmission on one linear polarization and reception on two orthogonal linear polarizations for adequate characterization of the surface. To meet this requirement at minimum cost, it was desirable to use two identically polarized shaped beam antennas and to change the polarization of one of them by a polarization conversion plate. The plate was realized as a four-layer meanderline polarizer designed to convert horizontal polarization to vertical.

  9. A dual polarized antenna system using a meanderline polarizer

    NASA Technical Reports Server (NTRS)

    Burger, H. A.

    1978-01-01

    Certain applications of synthetic aperture radars require transmitting on one linear polarization and receiving on two orthogonal linear polarizations for adequate characterization of the surface. To meet the current need at minimum cost, it was desirable to use two identical horizontally polarized shaped beam antennas and to change the polarization of one of them by a polarization conversion plate. The plate was realized as a four-layer meanderline polarizer designed to convert horizontal polarization to vertical.

  10. Enhanced polarization of (11–22) semi-polar InGaN nanorod array structure

    SciTech Connect

    Athanasiou, M.; Smith, R. M.; Hou, Y.; Zhang, Y.; Gong, Y.; Wang, T.

    2015-10-05

    By means of a cost effective nanosphere lithography technique, an InGaN/GaN multiple quantum well structure grown on (11–22) semipolar GaN has been fabricated into two dimensional nanorod arrays which form a photonic crystal (PhC) structure. Such a PhC structure demonstrates not only significantly increased emission intensity, but also an enhanced polarization ratio of the emission. This is due to an effective inhibition of the emission in slab modes and then redistribution to the vertical direction, thus minimizing the light scattering processes that lead to randomizing of the optical polarization. The PhC structure is designed based on a standard finite-difference-time-domain simulation, and then optically confirmed by detailed time-resolved photoluminescence measurements. The results presented pave the way for the fabrication of semipolar InGaN/GaN based emitters with both high efficiency and highly polarized emission.

  11. Widespread spin polarization effects in photoemission from topological insulators

    SciTech Connect

    Jozwiak, C.; Chen, Y. L.; Fedorov, A. V.; Analytis, J. G.; Rotundu, C. R.; Schmid, A. K.; Denlinger, J. D.; Chuang, Y.-D.; Lee, D.-H.; Fisher, I. R.; Birgeneau, R. J.; Shen, Z.-X.; Hussain, Z.; Lanzara, A.

    2011-06-22

    High-resolution spin- and angle-resolved photoemission spectroscopy (spin-ARPES) was performed on the three-dimensional topological insulator Bi{sub 2}Se{sub 3} using a recently developed high-efficiency spectrometer. The topological surface state's helical spin structure is observed, in agreement with theoretical prediction. Spin textures of both chiralities, at energies above and below the Dirac point, are observed, and the spin structure is found to persist at room temperature. The measurements reveal additional unexpected spin polarization effects, which also originate from the spin-orbit interaction, but are well differentiated from topological physics by contrasting momentum and photon energy and polarization dependencies. These observations demonstrate significant deviations of photoelectron and quasiparticle spin polarizations. Our findings illustrate the inherent complexity of spin-resolved ARPES and demonstrate key considerations for interpreting experimental results.

  12. Polarization feedback laser stabilization

    DOEpatents

    Esherick, P.; Owyoung, A.

    1987-09-28

    A system for locking two Nd:YAG laser oscillators includes an optical path for feeding the output of one laser into the other with different polarizations. Elliptical polarization is incorporated into the optical path so that the change in polarization that occurs when the frequencies coincide may be detected to provide a feedback signal to control one laser relative to the other. 4 figs.

  13. Long-Lived Hole Spin/Valley Polarization Probed by Kerr Rotation in Monolayer WSe2.

    PubMed

    Song, Xinlin; Xie, Saien; Kang, Kibum; Park, Jiwoong; Sih, Vanessa

    2016-08-10

    Time-resolved Kerr rotation and photoluminescence measurements are performed on MOCVD-grown monolayer tungsten diselenide (WSe2). We observe a surprisingly long-lived Kerr rotation signal (∼80 ns) at 10 K, which is attributed to spin/valley polarization of the resident holes. This polarization is robust to transverse magnetic field (up to 0.3 T). Wavelength-dependent measurements reveal that only excitation near the free exciton energy generates this long-lived spin/valley polarization.

  14. [Hospital-acquired urinary tract infections].

    PubMed

    Adukauskiene, Dalia; Cicinskaite, Ilona; Vitkauskiene, Astra; Macas, Andrius; Tamosiūnas, Ramūnas; Kinderyte, Aida

    2006-01-01

    Urinary tract infections are responsible for 40-60% of all hospital-acquired infections. Increased age of patients and comorbid diseases render hospitalized patients more susceptible to infection. Almost 80% of hospital-acquired urinary tract infections are associated with urinary catheters, and only 5-10% of urinary infections are caused by invasive manipulations in the urogenital tract. Pathogens of hospital-acquired urinary tract infections are frequently multi-resistant, and antibiotic therapy can only be successful when the complicating factors are eliminated or urodynamic function is restored. For treatment of complicated hospital-acquired urinary tract infections, the antibiotics must exhibit adequate pharmacodynamic and pharmacokinetic properties: high renal clearance of unmetabolized form with good antimicrobial activity in both acidic and alkaline urine. For selection of empirical treatment of hospital-acquired urinary tract infections, it is necessary to evaluate localization of infection, its severity, possible isolates, and the most frequent pathogens in the department where patient is treated. The best choice for the starting the antimicrobial therapy is the cheapest narrow-spectrum effective antibiotic in the treatment of urinary tract infection until microbiological evaluation of pathogens will be received. Adequate management of urinary tract infections lowers the rate of complications, requirements for antibacterial treatment, selection of multi-resistant isolates and is cost effective.

  15. Polarized negative ions

    SciTech Connect

    Haeberli, W.

    1981-04-01

    This paper presents a survey of methods, commonly in use or under development, to produce beams of polarized negative ions for injection into accelerators. A short summary recalls how the hyperfine interaction is used to obtain nuclear polarization in beams of atoms. Atomic-beam sources for light ions are discussed. If the best presently known techniques are incorporated in all stages of the source, polarized H/sup -/ and D/sup -/ beams in excess of 10 ..mu..A can probably be achieved. Production of polarized ions from fast (keV) beams of polarized atoms is treated separately for atoms in the H(25) excited state (Lamb-Shift source) and atoms in the H(1S) ground state. The negative ion beam from Lamb-Shift sources has reached a plateau just above 1 ..mu..A, but this beam current is adequate for many applications and the somewhat lower beam current is compensated by other desirable characteristics. Sources using fast polarized ground state atoms are in a stage of intense development. The next sections summarize production of polarized heavy ions by the atomic beam method, which is well established, and by optical pumping, which has recently been demonstrated to yield very large nuclear polarization. A short discussion of proposed ion sources for polarized /sup 3/He/sup -/ ions is followed by some concluding remarks.

  16. Polarization at SLC

    SciTech Connect

    Swartz, M.L.

    1988-07-01

    The SLAC Linear Collider has been designed to readily accommodate polarized electron beams. Considerable effort has been made to implement a polarized source, a spin rotation system, and a system to monitor the beam polarization. Nearly all major components have been fabricated. At the current time, several source and polarimeter components have been installed. The installation and commissioning of the entire system will take place during available machine shutdown periods as the commissioning of SLC progresses. It is expected that a beam polarization of 45% will be achieved with no loss in luminosity. 13 refs., 15 figs.

  17. Dirac cones, Floquet side bands, and theory of time-resolved angle-resolved photoemission

    NASA Astrophysics Data System (ADS)

    Farrell, Aaron; Arsenault, A.; Pereg-Barnea, T.

    2016-10-01

    Pump-probe techniques with high temporal resolution allow one to drive a system of interest out of equilibrium and at the same time probe its properties. Recent advances in these techniques open the door to studying new, nonequilibrium phenomena such as Floquet topological insulators and superconductors. These advances also necessitate the development of theoretical tools for understanding the experimental findings and predicting new ones. In the present paper, we provide a theoretical foundation to understand the nonequilibrium behavior of a Dirac system. We present detailed numerical calculations and simple analytic results for the time evolution of a Dirac system irradiated by light. These results are framed by appealing to the recently revitalized notion of side bands [A. Farrell and T. Pereg-Barnea, Phys. Rev. Lett. 115, 106403 (2015), 10.1103/PhysRevLett.115.106403; Phys. Rev. B 93, 045121 (2016), 10.1103/PhysRevB.93.045121], extended to the case of nonperiodic drive where the fast oscillations are modified by an envelope function. We apply this formalism to the case of photocurrent generated by a second probe pulse. We find that, under the application of circularly polarized light, a Dirac point only ever splits into two copies of side bands. Meanwhile, the application of linearly polarized light leaves the Dirac point intact while producing side bands. In both cases the population of the side bands are time dependent through their nonlinear dependence on the envelope of the pump pulse. Our immediate interest in this work is in connection to time- and angle-resolved photoemission experiments, where we find excellent qualitative agreement between our results and those in the literature [Wang et al., Science 342, 453 (2013), 10.1126/science.1239834]. However, our results are general and may prove useful beyond this particular application and should be relevant to other pump-probe experiments.

  18. Propagation of Dynamic Nuclear Polarization across the Xenon Cluster Boundaries: Elucidation of the Spin-Diffusion Bottleneck

    PubMed Central

    Pourfathi, M.; Kuzma, N. N.; Kara, H.; Ghosh, R. K.; Shaghaghi, H.; Kadlecek, S. J.; Rizi, R. R.

    2013-01-01

    Earlier dynamic nuclear polarization (DNP) experiments with frozen xenon/1-propanol/trityl mixtures have demonstrated spontaneous formation of pure xenon clusters above 120 K, enabling spectrally-resolved real-time measurements of 129Xe nuclear magnetization in the clusters and in the surrounding radical-rich matrix. A spin-diffusion bottleneck was postulated to explain the peculiar time evolution of 129Xe signals in the clusters as well as the apparent discontinuity of 129Xe polarization across the cluster boundaries. A self-contained ab initio model of nuclear spin diffusion in heterogeneous systems is developed here, incorporating the intrinsic T1 relaxation towards the temperature-dependent equilibrium along with the spin-diffusion coefficients based on the measured NMR line widths and the known atomic densities in each compartment. This simple model provides the physical basis for the observed spin-diffusion bottleneck and is in a good quantitative agreement with the earlier measurements. A simultaneous fit of the model to the time-dependent NMR data at two different DNP frequencies provides excellent estimates of the cluster size, the intrinsic sample temperature, and 129Xe T1 constants. The model was also applied to the NMR data acquired during relaxation towards thermal equilibrium after microwaves were turned off to estimate T1 relaxation time constants inside and outside the clusters. Fitting the model to data during and after DNP provides estimates of cluster size that are in complete agreement. PMID:23981341

  19. Detection of spin-resolved electronic structures from a buried ferromagnetic layer utilizing forward Mott scattering

    SciTech Connect

    Ueda, S.; Mizuguchi, M.; Kojima, T.; Takanashi, K.; Ishimaru, S.; Tsujikawa, M.; Shirai, M.

    2014-03-31

    We report ultrahigh-resolution spin-resolved hard X-ray photoemission (HAXPES) for a buried FeNi alloy film. By utilizing the forward Mott scattering in a Au layer on FeNi, our spin-resolved HAXPES method does not require a standard spin detector and allows us to use the multi-channel electron detection system for the high-efficient electron detection as used in conventional photoemission spectroscopy. A combination of the forward Mott scattering and multi-channel detection leads us to measure a clear spin polarization as well as spin-resolved majority and minority states in the Fe 2p core-level spectra without using the standard spin detector. This method enables us to measure spin-resolved core-level spectra for buried ferromagnetic materials.

  20. MgII Linear Polarization Measurements Using the MSFC Solar Ultraviolet Magnetograph

    NASA Technical Reports Server (NTRS)

    West, Edward; Cirtain, Jonathan; Kobayahsi, Ken; Davis, John; Gary, Allen; Adams, Mitzi

    2011-01-01

    This paper will describe the Marshall Space Flight Center's Solar Ultraviolet Magnetograph (SUMI) sounding rocket program, with emphasis on the polarization characteristics of the VUV optics and their spectral, spatial and polarization resolution. SUMI's first flight (7/30/2010) met all of its mission success criteria and this paper will describe the data that was acquired with emphasis on the MgII linear polarization measurements.

  1. MgII Linear Polarization Measurements Using the MSFC Solar Ultraviolet Magnetograph Sounding Rocket

    NASA Technical Reports Server (NTRS)

    West, Edward; Cirtain, Jonathan; Kobayashi, Ken; Davis, John; Gary, Allen

    2011-01-01

    This paper will describe the Marshall Space Flight Center's Solar Ultraviolet Magnetograph Investigation (SUMI) sounding rocket program, with emphasis on the polarization characteristics of the VUV optics and their spectral, spatial and polarization resolution. SUMI's first flight (7/30/2010) met all of its mission success criteria and this paper will describe the data that was acquired with emphasis on the MgII linear polarization measurements.

  2. RHIC Polarized proton operation

    SciTech Connect

    Huang, H.; Ahrens, L.; Alekseev, I.G.; Aschenauer, E.; Atoian, G.; Bai, M.; Bazilevsky, A.; Blaskiewicz, M.; Brennan, J.M.; Brown, K.A.; Bruno, D.; Connolly, R.; Dion, A.; D'Ottavio, T.; Drees, K.A.; Fischer, W.; Gardner, C.; Glenn, J.W.; Gu, X.; Harvey, M.; Hayes, T.; Hoff, L.; Hulsart, R.L.; Laster, J.; Liu, C.; Luo, Y.; MacKay, W.W.; Makdisi, Y.; Marr, G.J.; Marusic, A.; Meot, F.; Mernick, K.; Michnoff, R,; Minty, M.; Montag, C.; Morris, J.; Nemesure, S.; Poblaguev, A.; Ptitsyn, V.; Ranjibar, V.; Robert-Demolaize, G.; Roser, T.; J.; Severino, F.; Schmidke, B.; Schoefer, V.; Severino, F.; Smirnov, D.; Smith, K.; Steski, D.; Svirida, D.; Tepikian, S.; Trbojevic, D.; Tsoupas, N.; Tuozzolo, J. Wang, G.; Wilinski, M.; Yip, K.; Zaltsman, A.; Zelenski, A.; Zeno, K.; Zhang, S.Y.

    2011-03-28

    The Relativistic Heavy Ion Collider (RHIC) operation as the polarized proton collider presents unique challenges since both luminosity(L) and spin polarization(P) are important. With longitudinally polarized beams at the experiments, the figure of merit is LP{sup 4}. A lot of upgrades and modifications have been made since last polarized proton operation. A 9 MHz rf system is installed to improve longitudinal match at injection and to increase luminosity. The beam dump was upgraded to increase bunch intensity. A vertical survey of RHIC was performed before the run to get better magnet alignment. The orbit control is also improved this year. Additional efforts are put in to improve source polarization and AGS polarization transfer efficiency. To preserve polarization on the ramp, a new working point is chosen such that the vertical tune is near a third order resonance. The overview of the changes and the operation results are presented in this paper. Siberian snakes are essential tools to preserve polarization when accelerating polarized beams to higher energy. At the same time, the higher order resonances still can cause polarization loss. As seen in RHIC, the betatron tune has to be carefully set and maintained on the ramp and during the store to avoid polarization loss. In addition, the orbit control is also critical to preserve polarization. The higher polarization during this run comes from several improvements over last run. First we have a much better orbit on the ramp. The orbit feedback brings down the vertical rms orbit error to 0.1mm, much better than the 0.5mm last run. With correct BPM offset and vertical realignment, this rms orbit error is indeed small. Second, the jump quads in the AGS improved input polarization for RHIC. Third, the vertical tune was pushed further away from 7/10 snake resonance. The tune feedback maintained the tune at the desired value through the ramp. To calibrate the analyzing power of RHIC polarimeters at any energy above

  3. [Design of full-polarized and multi-spectral imaging system based on LCVR].

    PubMed

    Zhang, Ying; Zhao, Hui-jie; Cheng, Xuan; Xiong, Sheng-jun

    2011-05-01

    A new full-polarized multi-spectral imaging system is described, which uses electronically controlled LCVR (liquid crystal variable retarder) to modulate the full-polarized state of light in the visible to IR range. The system consisted of optical lenses, LCVRs, filters and CCD. Firstly, the system structure, working theory and optical design are introduced in the present paper. A polarization calibration method is provided and the calibration system was set up, which realized high-precision polarization calibration using a small polarized source. Then, a field experiment with the imaging system was carried out. Polarized spectral images with higher spectral and spatial resolution were collected. Finally, the data acquired were rough processed to get polarization degree image of the targets. It is concluded that the experiment has proved that the imaging system is effective in obtaining full-polarized and multi- spectral data. The image captured by the system can be applied to object identification and object classification.

  4. Polarized Light: Three Demonstrations.

    ERIC Educational Resources Information Center

    Goehmann, Ruth; Welty, Scott

    1984-01-01

    Describes three demonstrations used in the Chicago Museum of Science and Industry polarized light show. The procedures employed are suitable for the classroom by using smaller polarizers and an overhead projector. Topic areas include properties of cellophane tape, nondisappearing arrows, and rope through a picket fence. (JN)

  5. Polar Science Is Cool!

    ERIC Educational Resources Information Center

    Weeks, Sophie

    2012-01-01

    Children are fascinated by the fact that polar scientists do research in extremely cold and dangerous places. In the Arctic they might be viewed as lunch by a polar bear. In the Antarctic, they could lose toes and fingers to frostbite and the wind is so fast it can rip skin off. They camp on ice in continuous daylight, weeks from any form of…

  6. The Polar Insulation Investigation

    ERIC Educational Resources Information Center

    Urban-Rich, Juanita

    2006-01-01

    In this article, the author developed an activity called "The Polar Insulation Investigation." This activity builds on students' natural interest in "things polar" and introduces them to animal adaptations in a unique way. The aim of the exploration is to determine the role of animal coverings (e.g., blubber, fur, and feathers) and to see which is…

  7. Our Polar Past

    ERIC Educational Resources Information Center

    Clary, Renee; Wandersee, James

    2009-01-01

    The study of polar exploration is fascinating and offers students insights into the history, culture, and politics that affect the developing sciences at the farthest ends of Earth. Therefore, the authors think there is value in incorporating polar exploration accounts within modern science classrooms, and so they conducted research to test their…

  8. Polarization Radar Processing Technology

    DTIC Science & Technology

    1989-10-01

    Oi"C FILE ( J qII RADC-TR-89-144 In-House Report October 1989 AD-A215 242 POLARIZATION RADAR PROCESSING TECHNOLOGY Kenneth C. Stiefvater, Russell D...NO. NO. NO. ACCESSION NO. 62702F 4506 11 58 11. TITLE (Include Security Classification) POLARIZATION RADAR PROCESSING TECHNOLOGY 12. PERSONAL AUTHOR(S

  9. Spin polarization of the split Kondo state.

    PubMed

    von Bergmann, Kirsten; Ternes, Markus; Loth, Sebastian; Lutz, Christopher P; Heinrich, Andreas J

    2015-02-20

    Spin-resolved scanning tunneling microscopy is employed to quantitatively determine the spin polarization of the magnetic field-split Kondo state. Tunneling conductance spectra of a Kondo-screened magnetic atom are evaluated within a simple model taking into account inelastic tunneling due to spin excitations and two Kondo peaks positioned symmetrically around the Fermi energy. We fit the spin state of the Kondo-screened atom with a spin Hamiltonian independent of the Kondo effect and account for Zeeman splitting of the Kondo peak in the magnetic field. We find that the width and the height of the Kondo peaks scales with the Zeeman energy. Our observations are consistent with full spin polarization of the Kondo peaks, i.e., a majority spin peak below the Fermi energy and a minority spin peak above.

  10. Nomenclature of polarized light - Elliptical polarization

    NASA Technical Reports Server (NTRS)

    Clarke, D.

    1974-01-01

    Alternative handedness and sign conventions for relating the orientation of elliptical polarization are discussed. The discussion proceeds under two headings: (1) snapshot picture, where the emphasis for the convention is contained in the concept of handedness; and (2) angular momentum consideration, where the emphasis for the convention is strongly associated with mathematical convention and the sign of the fourth Stokes parameter.

  11. Resolving thermoelectric "paradox" in superconductors.

    PubMed

    Shelly, Connor D; Matrozova, Ekaterina A; Petrashov, Victor T

    2016-02-01

    For almost a century, thermoelectricity in superconductors has been one of the most intriguing topics in physics. During its early stages in the 1920s, the mere existence of thermoelectric effects in superconductors was questioned. In 1944, it was demonstrated that the effects may occur in inhomogeneous superconductors. Theoretical breakthrough followed in the 1970s, when the generation of a measurable thermoelectric magnetic flux in superconducting loops was predicted; however, a major crisis developed when experiments showed puzzling discrepancies with the theory. Moreover, different experiments were inconsistent with each other. This led to a stalemate in bringing theory and experiment into agreement. With this work, we resolve this stalemate, thus solving this long-standing "paradox," and open prospects for exploration of novel thermoelectric phenomena predicted recently.

  12. Polarization of clouds

    NASA Astrophysics Data System (ADS)

    Goloub, Philippe; Herman, Maurice; Parol, Frederic

    1995-12-01

    This paper reports the main results concerning polarization by clouds derived from POLDER (polarization and directionality of earth's reflectances) airborne version. These results tend to confirm the high information content in the polarization (phase, altimetry). The preliminary results of EUCREX'94 (European Cloud Radiation Experiment) evidenced the drastically different polarized signatures for ice crystals and water droplets. Here we report systematic and statistically significative observations over the whole EUCREX data set. The results show that the cirrus exhibit their own signature. Preliminary observations performed during CLEOPATRA'91 (Cloud Experiment Ober Pfaffenhofen And Transport) and EUCREX'94 campaigns have shown the feasibility of cloud altimetry using spectral information (443 nm and 865 nm) of the polarized light over liquid water droplets clouds. Altimetry technique has been generalized on ASTEX-SOFIA'92 and EUCREX'94 data sets. All these results are presented and discussed in this paper.

  13. Parallel Polarization State Generation

    NASA Astrophysics Data System (ADS)

    She, Alan; Capasso, Federico

    2016-05-01

    The control of polarization, an essential property of light, is of wide scientific and technological interest. The general problem of generating arbitrary time-varying states of polarization (SOP) has always been mathematically formulated by a series of linear transformations, i.e. a product of matrices, imposing a serial architecture. Here we show a parallel architecture described by a sum of matrices. The theory is experimentally demonstrated by modulating spatially-separated polarization components of a laser using a digital micromirror device that are subsequently beam combined. This method greatly expands the parameter space for engineering devices that control polarization. Consequently, performance characteristics, such as speed, stability, and spectral range, are entirely dictated by the technologies of optical intensity modulation, including absorption, reflection, emission, and scattering. This opens up important prospects for polarization state generation (PSG) with unique performance characteristics with applications in spectroscopic ellipsometry, spectropolarimetry, communications, imaging, and security.

  14. Parallel Polarization State Generation

    PubMed Central

    She, Alan; Capasso, Federico

    2016-01-01

    The control of polarization, an essential property of light, is of wide scientific and technological interest. The general problem of generating arbitrary time-varying states of polarization (SOP) has always been mathematically formulated by a series of linear transformations, i.e. a product of matrices, imposing a serial architecture. Here we show a parallel architecture described by a sum of matrices. The theory is experimentally demonstrated by modulating spatially-separated polarization components of a laser using a digital micromirror device that are subsequently beam combined. This method greatly expands the parameter space for engineering devices that control polarization. Consequently, performance characteristics, such as speed, stability, and spectral range, are entirely dictated by the technologies of optical intensity modulation, including absorption, reflection, emission, and scattering. This opens up important prospects for polarization state generation (PSG) with unique performance characteristics with applications in spectroscopic ellipsometry, spectropolarimetry, communications, imaging, and security. PMID:27184813

  15. Cell polarity: mechanochemical patterning.

    PubMed

    Goehring, Nathan W; Grill, Stephan W

    2013-02-01

    Nearly every cell type exhibits some form of polarity, yet the molecular mechanisms vary widely. Here we examine what we term 'chemical systems' where cell polarization arises through biochemical interactions in signaling pathways, 'mechanical systems' where cells polarize due to forces, stresses and transport, and 'mechanochemical systems' where polarization results from interplay between mechanics and chemical signaling. To reveal potentially unifying principles, we discuss mathematical conceptualizations of several prototypical examples. We suggest that the concept of local activation and global inhibition - originally developed to explain spatial patterning in reaction-diffusion systems - provides a framework for understanding many cases of cell polarity. Importantly, we find that the core ingredients in this framework - symmetry breaking, self-amplifying feedback, and long-range inhibition - involve processes that can be chemical, mechanical, or even mechanochemical in nature.

  16. Cost of hospital-acquired infection.

    PubMed

    Hassan, Mahmud; Tuckman, Howard P; Patrick, Robert H; Kountz, David S; Kohn, Jennifer L

    2010-01-01

    The authors assessed the costs of hospital-acquired infections using rigorous econometric methods on publicly available data, controlling for the interdependency of length of stay and the incidence of hospital acquired infection, and estimated the cost shares of different payers. They developed a system of equations involving length of stay, incidence of infection, and the total hospital care cost to be estimated using simultaneous equations system. The main data came from the State of New Jersey UB 92 for 2004, complimented with data from the Annual Survey of Hospitals by the American Hospital Association and the Medicare Cost Report of 2004. The authors estimated that an incidence of hospital acquired infection increases the hospital care cost of a patient by $10,375 and it increases the length of stay by 3.30 days, and that a disproportionately higher portion of the cost is attributable to Medicare. They conclude that reliable cost estimates of hospital-acquired infections can be made using publicly available data. Their estimate shows a much larger aggregate cost of $16.6 billion as opposed to $5 billion reported by the Centers for Disease Control and Prevention but much less than $29 billion as reported elsewhere in the literature.

  17. 7 CFR 989.17 - Acquire.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 7 Agriculture 8 2012-01-01 2012-01-01 false Acquire. 989.17 Section 989.17 Agriculture Regulations of the Department of Agriculture (Continued) AGRICULTURAL MARKETING SERVICE (Marketing Agreements and Orders; Fruits, Vegetables, Nuts), DEPARTMENT OF AGRICULTURE RAISINS PRODUCED FROM GRAPES GROWN...

  18. How Did Light Acquire a Velocity?

    ERIC Educational Resources Information Center

    Lauginie, Pierre

    2013-01-01

    We discuss how light acquired a velocity through history, from the ancient Greeks to the early modern era. Combining abstract debates, models of light, practical needs, planned research and chance, this history illustrates several key points that should be brought out in science education.

  19. Sexually acquired Salmonella Typhi urinary tract infection.

    PubMed

    Wielding, Sally; Scott, Gordon

    2016-05-01

    We report a case of isolated urinary Salmonella enterica serotype Typhi in an HIV-positive man who has sex with men. He was clinically well and blood and stool cultures were negative, indicating that this may have been a sexually acquired urinary tract infection.

  20. Acquired nasal deformities in fighter pilots.

    PubMed

    Schreinemakers, Joyce R C; van Amerongen, Pieter; Kon, Moshe

    2010-07-01

    Fighter pilots may develop slowly progressive deformities of their noses during their flying careers. The spectrum of deformities that may be acquired ranges from soft tissue to osseous changes. The main cause is the varying pressure exerted by the oxygen mask on the skin and bony pyramid of the nose during flying.

  1. 7 CFR 989.17 - Acquire.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 7 Agriculture 8 2013-01-01 2013-01-01 false Acquire. 989.17 Section 989.17 Agriculture Regulations of the Department of Agriculture (Continued) AGRICULTURAL MARKETING SERVICE (MARKETING AGREEMENTS AND ORDERS; FRUITS, VEGETABLES, NUTS), DEPARTMENT OF AGRICULTURE RAISINS PRODUCED FROM GRAPES GROWN...

  2. 7 CFR 989.17 - Acquire.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 7 Agriculture 8 2010-01-01 2010-01-01 false Acquire. 989.17 Section 989.17 Agriculture Regulations of the Department of Agriculture (Continued) AGRICULTURAL MARKETING SERVICE (Marketing Agreements and Orders; Fruits, Vegetables, Nuts), DEPARTMENT OF AGRICULTURE RAISINS PRODUCED FROM GRAPES GROWN...

  3. 7 CFR 989.17 - Acquire.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 7 Agriculture 8 2014-01-01 2014-01-01 false Acquire. 989.17 Section 989.17 Agriculture Regulations of the Department of Agriculture (Continued) AGRICULTURAL MARKETING SERVICE (MARKETING AGREEMENTS AND ORDERS; FRUITS, VEGETABLES, NUTS), DEPARTMENT OF AGRICULTURE RAISINS PRODUCED FROM GRAPES GROWN...

  4. 7 CFR 989.17 - Acquire.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 7 Agriculture 8 2011-01-01 2011-01-01 false Acquire. 989.17 Section 989.17 Agriculture Regulations of the Department of Agriculture (Continued) AGRICULTURAL MARKETING SERVICE (Marketing Agreements and Orders; Fruits, Vegetables, Nuts), DEPARTMENT OF AGRICULTURE RAISINS PRODUCED FROM GRAPES GROWN...

  5. Eye Movement Correlates of Acquired Central Dyslexia

    ERIC Educational Resources Information Center

    Schattka, Kerstin I.; Radach, Ralph; Huber, Walter

    2010-01-01

    Based on recent progress in theory and measurement techniques, the analysis of eye movements has become one of the major methodological tools in experimental reading research. Our work uses this approach to advance the understanding of impaired information processing in acquired central dyslexia of stroke patients with aphasia. Up to now there has…

  6. Group Treatment in Acquired Brain Injury Rehabilitation

    ERIC Educational Resources Information Center

    Bertisch, Hilary; Rath, Joseph F.; Langenbahn, Donna M.; Sherr, Rose Lynn; Diller, Leonard

    2011-01-01

    The current article describes critical issues in adapting traditional group-treatment methods for working with individuals with reduced cognitive capacity secondary to acquired brain injury. Using the classification system based on functional ability developed at the NYU Rusk Institute of Rehabilitation Medicine (RIRM), we delineate the cognitive…

  7. Acquiring a Second Language for School.

    ERIC Educational Resources Information Center

    Collier, Virginia P.

    1995-01-01

    This report offers a conceptual model for use with language minority children who are entering a new school when they must acquire the language of the majority student population. The model has four development components or processes: sociocultural, linguistic, academic, and cognitive. These four components are described in detail. Research is…

  8. Acquired immunodeficiency syndrome with subacute sclerosing panencephalitis.

    PubMed

    Gowda, Vykuntaraju K N; Sukanya, V; Shivananda

    2012-11-01

    A 7-year-old boy with acquired immunodeficiency syndrome, receiving antiretroviral drugs for 2 years, presented with a recent onset of myoclonic jerks and cognitive deterioration. On examination, he manifested myoclonic jerks once every 10-15 seconds. His electroencephalogram indicated periodic complexes, and his cerebrospinal fluid tested positive for measles antibodies.

  9. Time resolved spectroscopic NMR imaging using hyperpolarized 129Xe

    NASA Astrophysics Data System (ADS)

    Han, S.; Kühn, H.; Häsing, F. W.; Münnemann, K.; Blümich, B.; Appelt, S.

    2004-04-01

    We have visualized the melting and dissolution processes of xenon (Xe) ice into different solvents using the methods of nuclear magnetic resonance (NMR) spectroscopy, imaging, and time resolved spectroscopic imaging by means of hyperpolarized 129Xe. Starting from the initial condition of a hyperpolarized solid Xe layer frozen on top of an ethanol (ethanol/water) ice block we measured the Xe phase transitions as a function of time and temperature. In the pure ethanol sample, pieces of Xe ice first fall through the viscous ethanol to the bottom of the sample tube and then form a thin layer of liquid Xe/ethanol. The xenon atoms are trapped in this liquid layer up to room temperature and keep their magnetization over a time period of 11 min. In the ethanol/water mixture (80 vol%/20%), most of the polarized Xe liquid first stays on top of the ethanol/water ice block and then starts to penetrate into the pores and cracks of the ethanol/water ice block. In the final stage, nearly all the Xe polarization is in the gas phase above the liquid and trapped inside the pores. NMR spectra of homogeneous samples of pure ethanol containing thermally polarized Xe and the spectroscopic images of the melting process show that very high concentrations of hyperpolarized Xe (about half of the density of liquid Xe) can be stored or delivered in pure ethanol.

  10. Polarized neutron reflectometry of magnetic nanostructures

    NASA Astrophysics Data System (ADS)

    Toperverg, B. P.

    2015-12-01

    Among a number of methods employed to characterize various types of magnetic nano-structures Polarized Neutron Reflectometry (PNR) is shown to be a unique tool providing a scope of quantitative information on magnetization arrangement over relevant scales. Deeply penetrating into materials neutron spins are able to resolve vectorial profile of magnetic induction with accuracy of a fraction of Oersted over a fraction of nano-meters. This property is exploited in measurements of specular PNR which hence constitutes the method of depth resolved vector magnetometry widely used to examine magnetic states in exchange coupled magnetic superlattices, exchange bias systems, spin valves, exchange springs, superconducting/ferromagnetic heterostructure, etc. Off-specular polarized neutron scattering (OS-PNS) measures the in-plane magnetization distribution over scales from hundreds of nanoto hundreds of micrometers providing, in combination with specular PNR, access to lateral long range fluctuations of the magnetization vector and magnetic domains in these systems. OSPNS is especially useful in studies of co-operative magnetization reversal processes in various films and multilayers laterally patterned into periodic arrays of stripes, or islands of various dimentions, shapes, internal structures, etc., representing an interest for e.g. spintronics. Smaller sizes of 10?100 nm are accessed with the method of Polarized Neutrons Grazing Incidence Small Angle Scattering (PN-GISAS), which in a combination with specular PNR and OS-PNS is used to study self-assembling of magnetic nano-particles on flat surfaces, while Polarized Neutron Grazing Incidence Diffraction (PN-GID) complete the scope of magnetic information over wide range of scales in 3D space. The review of recent results obtained employing the methods listed above is preceded by the detailed theoretical consideration and exemplified by new developments addressing with PNR fast magnetic kinetics in nano-systems.

  11. Polarization Lidar for Shallow Water Depth Measurement

    NASA Astrophysics Data System (ADS)

    Mitchell, S.; Thayer, J. P.

    2011-12-01

    A bathymetric, polarization lidar system transmitting at 532 nanometers is developed for applications of shallow water depth measurement. The technique exploits polarization attributes of the probed water body to isolate surface and floor returns, enabling constant fraction detection schemes to determine depth. The minimum resolvable water depth is no longer dictated by the system's laser or detector pulse width and can achieve better than an order of magnitude improvement over current water depth determination techniques. In laboratory tests, a Nd:YAG microchip laser coupled with polarization optics, a single photomultiplier tube, a constant fraction discriminator and a time to digital converter are used to target various water depths. Measurement of 1 centimeter water depths with an uncertainty of ±3 millimeters are demonstrated using the technique. Additionally, a dual detection channel version of the lidar system is in development, permitting simultaneous measurement of co- and cross-polarized signals scattered from the target water body. This novel approach enables new approaches to designing laser bathymetry systems for shallow depth determination from remote platforms while not compromising deep water depth measurement, supporting comprehensive hydrodynamic studies.

  12. Structural and functional hepatocyte polarity and liver disease

    PubMed Central

    Gissen, Paul; Arias, Irwin M.

    2015-01-01

    Summary Hepatocytes form a crucially important cell layer that separates sinusoidal blood from the canalicular bile. They have a uniquely organized polarity with a basal membrane facing liver sinusoidal endothelial cells, while one or more apical poles can contribute to several bile canaliculi jointly with the directly opposing hepatocytes. Establishment and maintenance of hepatocyte polarity is essential for many functions of hepatocytes and requires carefully orchestrated cooperation between cell adhesion molecules, cell junctions, cytoskeleton, extracellular matrix and intracellular trafficking machinery. The process of hepatocyte polarization requires energy and, if abnormal, may result in severe liver disease. A number of inherited disorders affecting tight junction and intracellular trafficking proteins have been described and demonstrate clinical and pathophysiological features overlapping those of the genetic cholestatic liver diseases caused by defects in canalicular ABC transporters. Thus both structural and functional components contribute to the final hepatocyte polarity phenotype. Many acquired liver diseases target factors that determine hepatocyte polarity, such as junctional proteins. Hepatocyte depolarization frequently occurs but is rarely recognized because hematoxylin-eosin staining does not identify the bile canaliculus. However, the molecular mechanisms underlying these defects are not well understood. Here we aim to provide an update on the key factors determining hepatocyte polarity and how it is affected in inherited and acquired diseases. PMID:26116792

  13. Interplanetary magnetic sector polarity inferred from polar geomagnetic field observations

    NASA Technical Reports Server (NTRS)

    Friis-Christensen, E.; Lassen, K.; Wilcox, J. M.; Gonzalez, W.; Colburn, D. S.

    1971-01-01

    In order to infer the interplanetary sector polarity from polar geomagnetic field diurnal variations, measurements were carried out at Godhavn and Thule (Denmark) Geomagnetic Observatories. The inferred interplanetary sector polarity was compared with the polarity observed at the same time by Explorer 33 and 35 magnetometers. It is shown that the polarity (toward or away from the sun) of the interplanetary magnetic field can be reliably inferred from observations of the polar cap geomagnetic fields.

  14. Neutron Polarizers Based on Polarized 3He

    SciTech Connect

    William M. Snow

    2005-05-01

    The goal of this work, which is a collaborative effort between Indiana University, NIST, and Hamilton College, is to extend the technique of polarized neutron scattering into new domains by the development and application of polarized 3He-based neutron spin filters. After the IPNS experiment which measured Zeeman sp[litting in surface scattered neutrons using a polarized 3He cell as a polarization analyzer transporterd by car from Bloomington to Chicago, the Indiana work focused on technical developments to improve the 3He polarization of the Indiana compression system. The compression system was rebuilt with a new valve system which allows gas trapped in the dead volume of the compressors at the end of the piston stroke to be exhausted and conducted back to the optical pumping cell where it can be repolarized. We also incorporated a new intermediate storage volume made at NIST from 1720 glass which will reduce polarization losses between the compressors. Furthermore, we improved the stability of the 1083 nm laser by cooling the LMA rod. We achieved 60% 3he polarization in the optical pumping cell and 87% preservation of the polarization during compression. In parallel we built a magnetically-shielded transport solenoid for use on neutron scattering instruments such as POSY which achieves a fractional field uniformity of better than 10-3 per cm. The field was mapped using an automated 3D field mapping system for in-situ measurement of magnetic field gradients Diluted magnetic semiconductors offer many exciting opportunities for investigation of spintronic effects in solids and are certain to be one of the most active areas of condensed matter physics over then next several years. These materials can act as efficient spin injectors for devices that make use of spin-dependent transport phenomena. We just (late July 2002) finished a neutron reflectivity experiment at NIST on a GaMnAs trilayer film. This material is a ferromagnetic semiconductor which is of interest

  15. Induced polarization signature of coal seam fires

    NASA Astrophysics Data System (ADS)

    Shao, Zhenlu; Revil, André; Mao, Deqiang; Wang, Deming

    2017-03-01

    Coal seam fires are a worldwide disaster of both ecological and economic importance. Their remote detection from the ground surface or using airborne techniques is required for developing efficient strategies to extinguish them. We investigate here the use of time-domain-induced polarization to localize coal seam fires. For laboratory experiments, we first introduce a modified time-domain-induced polarization methodology to quickly acquire and invert the secondary voltage distribution mapped after the shutdown of the primary current. A set of sandbox experiments is conducted in which coal is embedded into humidified sand. Raw coal alone generates significant induced polarization anomalies, above those shown by the sand. Even higher induced polarization anomalies are detected in presence of a coal seam fire. We postulate that the higher chargeability is due to the pyrolysis, which may enhance electronic polarization or the polarization associated with the cation exchange capacity (CEC) of the material. The position of the coal seam fire is well recovered inside the tank by inverting the secondary voltages in term of a source current density distribution. We also collected field data over a recognized coal seam fire in Colorado, USA. A chargeability anomaly (˜800 mV V-1) and a resistivity anomaly (˜1 Ohm m) are observed at the position of the coal seam fire. We propose a normalized burning front index (a scaled normalized chargeability) to image and localize, without ambiguity, the position of the coal seam fire in the subsurface. The 3-D reconstructed target is located below a negative self-potential anomaly (similarly to what is observed in laboratory experiments) and a temperature anomaly recorded at a depth of 30 cm.

  16. Induced polarization signature of coal seam fires

    NASA Astrophysics Data System (ADS)

    Shao, Zhenlu; Revil, André; Mao, Deqiang; Wang, Deming

    2016-12-01

    Coal seam fires are a worldwide disaster of both ecological and economic importance. Their remote detection from the ground surface or using airborne techniques is required for developing efficient strategies to extinguish them. We investigate here the use of time-domain induced polarization to localize coal seam fires. For laboratory experiments, we first introduce a modified time-domain induced polarization methodology to quickly acquire and invert the secondary voltage distribution mapped after the shutdown of the primary current. A set of sandbox experiments is conducted in which coal is embedded into humidified sand. Raw coal alone generates significant induced polarization anomalies, significantly above those shown by the sand. Even higher induced polarization anomalies are detected in presence of a coal seam fire. We postulate that the higher chargeability is due to the pyrolysis, which may enhance electronic polarization or the polarization associated with the cation exchange capacity of the material. The position of the coal seam fire is well recovered inside the tank by inverting the secondary voltages in term of a source current density distribution. We also collected field data over a recognized coal seam fire in Colorado, USA. A chargeability anomaly (˜800 mV/V) and a resistivity anomaly (˜1 Ohm m) are observed at the position of the coal seam fire. We propose a normalized burning front index (a scaled normalized chargeability) to image and localize, without ambiguity, the position of the coal seam fire in the subsurface. The 3D reconstructed target is located below a negative self-potential anomaly (similarly to what is observed in laboratory experiments) and a temperature anomaly recorded at a depth of 30 cm.

  17. Time Resolved FTIR Analysis of Combustion of Ethanol and Gasoline Combustion in AN Internal Combustion Engine

    NASA Astrophysics Data System (ADS)

    White, Allen R.; Sakai, Stephen; Devasher, Rebecca B.

    2011-06-01

    In order to pursue In Situ measurements in an internal combustion engine, a MegaTech Mark III transparent spark ignition engine was modified with a sapphire combustion chamber. This modification will allow the transmission of infrared radiation for time-resolved spectroscopic measurements by an infrared spectrometer. By using a Step-scan equipped Fourier transform spectrometer, temporally resolved infrared spectral data were acquired and compared for combustion in the modified Mark III engine. Measurements performed with the FTIR system provide insight into the energy transfer vectors that precede combustion and also provides an in situ measurement of the progress of combustion. Measurements were performed using ethanol and gasoline.

  18. Long term changes in the polar vortices

    NASA Astrophysics Data System (ADS)

    Braathen, Geir O.

    2015-04-01

    As the amount of halogens in the stratosphere is slowly declining and the ozone layer slowly recovers it is of interest to see how the meteorological conditions in the vortex develop over the long term since such changes might alter the foreseen ozone recovery. In conjunction with the publication of the WMO Antarctic and Arctic Ozone Bulletins, WMO has acquired the ERA Interim global reanalysis data set for several meteorological parameters. This data set goes from 1979 - present. These long time series of data can be used for several useful studies of the long term development of the polar vortices. Several "environmental indicators" for vortex change have been calculated, and a climatology, as well as trends, for these parameters will be presented. These indicators can act as yardsticks and will be useful for understanding past and future changes in the polar vortices and how these changes affect polar ozone depletion. Examples of indicators are: vortex mean temperature, vortex minimum temperature, vortex mean PV, vortex "importance" (PV*area), vortex break-up time, mean and maximum wind speed. Data for both the north and south polar vortices have been analysed at several isentropic levels from 350 to 850 K. A possible link between changes in PV and sudden stratospheric warmings will be investigated, and the results presented.

  19. Polarization at the SLC

    NASA Astrophysics Data System (ADS)

    Moffeit, Kenneth C.

    1989-05-01

    The Stanford Linear Collider was designed to accommodate polarized electron beams. Longitudinally polarized electrons colliding with unpolarized positrons at a center of mass energy near the Z0 mass can be used as novel and sensitive probes of the electroweak process. A gallium arsenide based photon emission source will provide a beam of longitudinally polarized electrons of about 45 percent polarization. A system of bend magnets and a superconducting solenoid will be used to rotate the spins so that the polarization is preserved while the 1.21 GeV electrons are stored in the damping ring. Another set of bend magnets and two superconducting solenoids orient the spin vectors so that longitudinal polarization of the electrons is achieved at the collision point with the unpolarized positrons. A system to monitor the polarization based on Mo/ller and Compton scattering will be used. Nearly all major components have been fabricated and tested. Subsystems of the source and polarimeters have been installed, and studies are in progress. The installation and commissioning of the entire system will take place during available machine shutdown periods as the commissioning of SLC progresses.

  20. Fiber-based lensless polarization holography for measuring Jones matrix parameters of polarization-sensitive materials.

    PubMed

    Liu, Xuan; Yang, Yang; Han, Lu; Guo, Cheng-Shan

    2017-04-03

    We report a fiber-based lensless holographic imaging system to realize a single-shot measurement of two dimensional (2-D) Jones matrix parameters of polarization-sensitive materials. In this system, a multi-source lensless off-axis Fresnel holographic recording geometry is adopted, and two optical fiber splitters are used to generate the multiple reference and illumination beams required for recording a four-channel angular-multiplexing polarization hologram (AMPH). Using this system and the method described in this paper, spatially resolved Jones matrix parameters of a polarization-sensitive material can be retrieved from one single-shot AMPH. We demonstrate the feasibility of the method by extracting a 2-D Jones matrix of a composite polarizer. Applications of the method to measure the Jones matrix maps of a stressed polymethyl methacrylate sample and a mica fragment are also presented. Benefit from the fiber-based and lensless off-axis holographic design, the system possesses a quite compact configuration, which provides a feasible approach for development of an integrated and portable system to measure Jones matrix parameters of polarization-sensitive materials.

  1. Animated Displays IV: Linear Polarization.

    ERIC Educational Resources Information Center

    Chagnon, Paul

    1993-01-01

    Describes several demonstrations that can be easily reproduced to help students understand optical polarization. Displays and supplement text include polarization by reflection; polarization by scattering; liquid crystals; optical activity; calcite; birefringent plastics; retardation plates; photoelasticity; and the "Optical Barber…

  2. Effect of laser polarization on quantum electrodynamical cascading

    SciTech Connect

    Bashmakov, V. F.; Nerush, E. N.; Kostyukov, I. Yu.; Fedotov, A. M.; Narozhny, N. B.

    2014-01-15

    Development of quantum electrodynamical (QED) cascades in a standing electromagnetic wave for circular and linear polarizations is simulated numerically with a 3D PIC-MC code. It is demonstrated that for the same laser energy the number of particles produced in a circularly polarized field is greater than in a linearly polarized field, though the acquiring mean energy per particle is larger in the latter case. The qualitative model of laser-assisted QED cascades is extended by including the effect of polarization of the field. It turns out that cascade dynamics is notably more complicated in the case of linearly polarized field, where separation into the qualitatively different “electric” and “magnetic” regions (where the electric field is stronger than the magnetic field and vice versa) becomes essential. In the “magnetic” regions, acceleration is suppressed, and moreover the high-energy electrons are even getting cooled by photon emission. The volumes of the “electric” and “magnetic” regions evolve periodically in time and so does the cascade growth rate. In contrast to the linear polarization, the charged particles can be accelerated by circularly polarized wave even in “magnetic region.” The “electric” and “magnetic” regions do not evolve in time, and cascade growth rate almost does not depend on time for circular polarization.

  3. Resolving Seamounts in Satellite Altimetry

    NASA Astrophysics Data System (ADS)

    Marks, K. M.; Smith, W. H.

    2006-12-01

    We have examined three factors influencing the use of satellite altimeter data to map seamounts and guyots in the deep ocean: (1) the resolution of seamount and guyot gravity anomalies by altimetry; (2) the non-linearity of the relationship between gravity and bathymetry; and (3) the homogeneity of the mass density within the seamount or guyot. When altimeter data are used to model the marine gravity anomaly field the result may have limited resolution due to noise levels in the altimeter data, track spacing of the satellite profiles, inclination angles of the orbits, and filters used to combine and interpolate the data (Sandwell and Smith, JGR, 1997). We compared the peak-to-trough amplitude of gravity anomalies in Sandwell and Smith`'s version 15.1 field to peak-to-trough amplitudes measured by gravimeters on board ships. The satellite gravity field amplitudes match ship measurements well over seamounts and guyots having volumes exceeding ~2000 km3. Over smaller volume seamounts, where the anomalies have most of their power at quite short wavelengths, the satellite field under-estimates the anomaly amplitude. If less filtering could be done, or a new mission with a lower noise level were flown, more of the anomalies associated with small seamounts might be resolved. Smith and Sandwell (Science, 1997) predicted seafloor topography from altimetric gravity assuming that the density of seafloor topography is nearly constant over ~100 km distances, and that the relationship between gravity and topography may be approximated by a liner filter over those distances. In fact, the true theoretical relationship is non-linear (Parker, Geophys. J. R. astr. Soc, 1972); it can be expressed as an N-th order expansion, with the N=1 term representing a linear filter and the N>1 terms accounting for higher-order corrections. We find that N=2 is a sufficient approximation at both seamounts and guyots. Constant density models of large volume guyots do not fit the observed gravity

  4. Polar Code Validation

    DTIC Science & Technology

    1989-09-30

    Unclassified 2a SECURITY CLASSiF-ICATiON AUTHORIT’Y 3 DIStRIBUTION AVAILABILITY OF REPORT N,A Approved for public release; 2o DECLASSIFICAIiON DOWNGRADING SCH DI...SUMMARY OF POLAR ACHIEVEMENTS ..... .......... 3 3 . POLAR CODE PHYSICAL MODELS ..... ............. 5 3.1 PL-ASMA Su ^"ru5 I1LS SH A...11 Structure of the Bipolar Plasma Sheath Generated by SPEAR I ... ...... 1 3 The POLAR Code Wake Model: Comparison with in Situ Observations . . 23

  5. GUIDE FOR POLARIZED NEUTRONS

    DOEpatents

    Sailor, V.L.; Aichroth, R.W.

    1962-12-01

    The plane of polarization of a beam of polarized neutrons is changed by this invention, and the plane can be flipped back and forth quicitly in two directions in a trouble-free manner. The invention comprises a guide having a plurality of oppositely directed magnets forming a gap for the neutron beam and the gaps are spaced longitudinally in a spiral along the beam at small stepped angles. When it is desired to flip the plane of polarization the magnets are suitably rotated to change the direction of the spiral of the gaps. (AEC)

  6. Molecular photoelectron holography with circularly polarized laser pulses.

    PubMed

    Yang, Weifeng; Sheng, Zhihao; Feng, Xingpan; Wu, Miaoli; Chen, Zhangjin; Song, Xiaohong

    2014-02-10

    We investigate the photoelectron momentum distribution of molecular-ion H2+driven by ultrashort intense circularly polarized laser pulses. Both numerical solutions of the time-dependent Schrödinger equation (TDSE) and a quasiclassical model indicate that the photoelectron holography (PH) with circularly polarized pulses can occur in molecule. It is demonstrated that the interference between the direct electron wave and rescattered electron wave from one core to its neighboring core induces the PH. Moreover, the results of the TDSE predict that there is a tilt angle between the interference pattern of the PH and the direction perpendicular to the molecular axis. Furthermore, the tilt angle is sensitively dependent on the wavelength of the driven circularly polarized pulse, which is confirmed by the quasiclassical calculations. The PH induced by circularly polarized laser pulses provides a tool to resolve the electron dynamics and explore the spatial information of molecular structures.

  7. Polarization insensitive imaging through polarization gratings.

    PubMed

    Nersisyan, Sarik R; Tabiryan, Nelson V; Hoke, Landa; Steeves, Diane M; Kimball, Brian R

    2009-02-02

    Liquid crystal polarization gratings exhibit high diffraction efficiency (approximately 100%) in thin material layers comparable to the radiation wavelength. We demonstrate that they can be combined for polarization-insensitive imaging and optical switching applications. A pair of closely spaced, parallel oriented, cycloidal polarization gratings is capable of canceling the diffractive property of an individual grating. As a result, the phase of the beam is not distorted, and holographic images can be formed through them. An anti-parallel arrangement results in a broader effective diffraction band and doubles the diffraction angle. Broadband diffraction spanning from 480 nm to beyond 900 nm wavelengths has been obtained for a pair of gratings with 500 nm and 633 nm peak diffraction wavelengths. Liquid crystal polymer cycloidal gratings were used in the study showing 98% diffraction efficiency over a large area, and allowed for the use of laser beams expanded to 25 mm. The characteristics of combined cycloidal gratings were tested with laser beams at both UV and red wavelengths.

  8. Uveitis as an initial manifestation of acquired immunodeficiency syndrome.

    PubMed

    Tsen, Chui-Lien; Chen, Shih-Chou; Chen, Yao-Shen; Sheu, Shwu-Jiuan

    2017-01-01

    Human immunodeficiency virus (HIV)/acquired immunodeficiency syndrome (AIDS) is a multisystem disease that can involve the human eyes. Using ophthalmic examination records from January 2006 to November 2015, we retrospectively reviewed all patients who were diagnosed with HIV/AIDS in our hospital. The study was performed at a tertiary referral center in southern Taiwan. Data included age, gender, ophthalmic examinations, systemic conditions, CD4 cell counts, course, and treatment. Eleven patients were identified as having AIDS with uveitis as their presenting manifestation. All were men, with a mean age of 39.5 ± 11.4 years (range 24-56). The mean CD4(+) T-cell counts were 91.7 ± 50.3 cells/μl (range 27-169). Ocular diagnoses included cytomegalovirus (CMV) retinitis in five patients, ocular syphilis in four patients, and ocular toxoplasmosis in two patients. Uveitis resolved in all patients after medical treatment. However, a retinal detachment developed in two eyes in CMV retinitis and one eye in ocular syphilis. Ocular manifestations are among the most common clinical features in patients with HIV/AIDS who have varying clinical presentations that affect almost all ocular structures. This study demonstrated that ocular findings could be an initial manifestation of an underlying disease. Awareness of ocular lesions in HIV/AIDS is important for early recognition and management.

  9. [Acquired paraneoplastic hypertrichosis lanuginosa associated with scleroderma].

    PubMed

    Valda Rodriguez, L; Torrico Velasco, J; Zeballos Vasconcellos, R

    1990-01-01

    Acquired hypertrichosis lanuginosa is universally recognized as an individual disease and seldom reported as a genuine paraneoplastic manifestation. We report the case of a 30-year old woman with acquired hypertrichosis lanuginosa. Due to the finding of a cervical lymph node metastasis, she was investigated for an internal neoplasm, but the original tumour could not be found by the usual methods. A bronchogenic carcinoma was discovered at autopsy. Beside hypertrichosis, this patient had other disorders not described in the literature as associated with that disease, viz.: progressive systemic scleroderma, fissured and hyperpigmented tongue, thrombocytopenia, galactorrhoea, axillary and pubic alopecia and overcurvature of toe nails. A review of similar cases in the literature provided clinical arguments in favour of the hormonal origin of this paraneoplastic hypertrichosis.

  10. Acquired portosystemic collaterals: anatomy and imaging.

    PubMed

    Leite, Andréa Farias de Melo; Mota, Américo; Chagas-Neto, Francisco Abaeté; Teixeira, Sara Reis; Elias Junior, Jorge; Muglia, Valdair Francisco

    2016-01-01

    Portosystemic shunts are enlarged vessels that form collateral pathological pathways between the splanchnic circulation and the systemic circulation. Although their causes are multifactorial, portosystemic shunts all have one mechanism in common-increased portal venous pressure, which diverts the blood flow from the gastrointestinal tract to the systemic circulation. Congenital and acquired collateral pathways have both been described in the literature. The aim of this pictorial essay was to discuss the distinct anatomic and imaging features of portosystemic shunts, as well as to provide a robust method of differentiating between acquired portosystemic shunts and similar pathologies, through the use of illustrations and schematic drawings. Imaging of portosystemic shunts provides subclinical markers of increased portal venous pressure. Therefore, radiologists play a crucial role in the identification of portosystemic shunts. Early detection of portosystemic shunts can allow ample time to perform endovascular shunt operations, which can relieve portal hypertension and prevent acute or chronic complications in at-risk patient populations.

  11. Clinical laboratory data: acquire, analyze, communicate, liberate.

    PubMed

    Azzazy, Hassan M E; Elbehery, Ali H A

    2015-01-01

    The availability of portable healthcare devices, which can acquire and transmit medical data to remote experts would dramatically affect healthcare in areas with poor infrastructure. Smartphones, which feature touchscreen computer capabilities and sophisticated cameras, have become widely available with over billion units shipped in 2013. In the clinical laboratory, smartphones have recently brought the capabilities of key instruments such as spectrophotometers, fluorescence analyzers and microscopes into the palm of the hand. Several research groups have developed sensitive and low-cost smartphone-based diagnostic assay prototypes for testing cholesterol, albumin, vitamin D, tumor markers, and the detection of infectious agents. This review covers the use of smartphones to acquire, analyze, communicate, and liberate clinical laboratory data. Smartphones promise to dramatically improve the quality and quantity of healthcare offered in resource-limited areas.

  12. Subcortical infarction resulting in acquired stuttering.

    PubMed

    Ciabarra, A M; Elkind, M S; Roberts, J K; Marshall, R S

    2000-10-01

    Stuttering is an uncommon presentation of acute stroke. Reported cases have often been associated with left sided cortical lesions, aphasia, and difficulties with other non-linguistic tests of rhythmic motor control. Three patients with subcortical lesions resulting in stuttering are discussed. In one patient the ability to perform time estimations with a computerised repetitive time estimation task was characterised. One patient had a pontine infarct with clinical evidence of cerebellar dysfunction. A second patient had a left basal ganglionic infarct and a disruption of timing estimation. A third patient had a left subcortical infarct and a mild aphasia. These findings expand the reported distribution of infarction that can result in acquired stuttering. Subcortical mechanisms of speech control and timing may contribute to the pathophysiology of acquired stuttering.

  13. Recognising and managing community-acquired pneumonia.

    PubMed

    Gibson, Vanessa

    2015-11-18

    Pneumonia remains a significant cause of morbidity and mortality in the UK and yet the seriousness of the disease is underestimated. Pneumonia can be life-threatening because the delicate tissues of the alveoli and pulmonary capillaries are susceptible to damage from the inflammatory response. This damage leads to consolidation that prevents the diffusion of oxygen and carbon dioxide, and this in turn can lead to respiratory failure. This article summarises guidance on the diagnosis and management of community-acquired pneumonia, and also includes information on the prevention of pneumonia. This information should be valuable to nurses working in a variety of clinical areas since patients with community-acquired pneumonia are encountered in primary, intermediate, secondary and critical care.

  14. Acquired versus familial demyelinative neuropathies in children.

    PubMed

    Miller, R G; Gutmann, L; Lewis, R A; Sumner, A J

    1985-01-01

    The electrophysiologic differences between chronic acquired demyelinative neuropathy and the demyelinative form of Charcot-Marie-Tooth disease have recently been reported. The present report extends these observations to include the genetically determined demyelinating neuropathies seen in metachromatic leukodystrophy, Krabbe's leukodystrophy, and Cockayne's syndrome. The electrophysiologic features of metachromatic leukodystrophy (five patients), Krabbe's (four patients), and Cockayne's syndrome (three patients) were all similar. There was uniform slowing of conduction (both in different nerves and in different nerve segments), and conduction block was not seen. These findings are consistent with a uniform degree of demyelination in multiple nerves and throughout the entire length of individual axons. Thus, uniform slowing of nerve conduction constitutes strong evidence for a familial demyelinative neuropathy, as opposed to the multifocal slowing seen in acute and chronic acquired demyelinative neuropathy.

  15. Acquired portosystemic collaterals: anatomy and imaging*

    PubMed Central

    Leite, Andréa Farias de Melo; Mota Jr., Américo; Chagas-Neto, Francisco Abaeté; Teixeira, Sara Reis; Elias Junior, Jorge; Muglia, Valdair Francisco

    2016-01-01

    Portosystemic shunts are enlarged vessels that form collateral pathological pathways between the splanchnic circulation and the systemic circulation. Although their causes are multifactorial, portosystemic shunts all have one mechanism in common-increased portal venous pressure, which diverts the blood flow from the gastrointestinal tract to the systemic circulation. Congenital and acquired collateral pathways have both been described in the literature. The aim of this pictorial essay was to discuss the distinct anatomic and imaging features of portosystemic shunts, as well as to provide a robust method of differentiating between acquired portosystemic shunts and similar pathologies, through the use of illustrations and schematic drawings. Imaging of portosystemic shunts provides subclinical markers of increased portal venous pressure. Therefore, radiologists play a crucial role in the identification of portosystemic shunts. Early detection of portosystemic shunts can allow ample time to perform endovascular shunt operations, which can relieve portal hypertension and prevent acute or chronic complications in at-risk patient populations. PMID:27777479

  16. Brucella abortus Infection Acquired in Microbiology Laboratories

    PubMed Central

    Fiori, Pier Luigi; Mastrandrea, Scilla; Rappelli, Paola; Cappuccinelli, Piero

    2000-01-01

    We report an outbreak of laboratory-acquired Brucella abortus infection originating in the accidental breakage of a centrifuge tube. A total of 12 laboratory workers were infected (attack rate of 31%), with an incubation time ranging from 6 weeks to 5 months. Antibody titers were evaluated weekly in all personnel exposed, allowing the diagnosis of the infection in most cases before the onset of clinical symptoms, so that specific therapy could be administrated. PMID:10790142

  17. Acquiring Secure Systems Through Information Economics

    DTIC Science & Technology

    2015-05-01

    Introduction “For all future weapons systems that DoD will acquire or procure, DoD will mandate specific cybersecurity standards for weapons...systems to meet. Acquisition and procurement policy and practice will be updated to promote effective cybersecurity throughout a system’s life cycle...physical damage or injury Motivating Contractor Efforts - Contractors have different priorities than the DOD when it comes to cybersecurity - Classic

  18. Earth Knowledge Acquired by Middle School Students

    NASA Technical Reports Server (NTRS)

    Ride, Sally

    2008-01-01

    Earth Knowledge Acquired by Middle School Students (EarthKAM), an education activity, allows middle school students to program a digital camera on board the International Space Station to photograph a variety of geographical targets for study in the classroom. Photos are made available on the web for viewing and study by participating schools around the world. Educators use the images for projects involving Earth Science, geography, physics, and social science.

  19. Acquired Antibiotic Resistance Genes: An Overview

    PubMed Central

    van Hoek, Angela H. A. M.; Mevius, Dik; Guerra, Beatriz; Mullany, Peter; Roberts, Adam Paul; Aarts, Henk J. M.

    2011-01-01

    In this review an overview is given on antibiotic resistance (AR) mechanisms with special attentions to the AR genes described so far preceded by a short introduction on the discovery and mode of action of the different classes of antibiotics. As this review is only dealing with acquired resistance, attention is also paid to mobile genetic elements such as plasmids, transposons, and integrons, which are associated with AR genes, and involved in the dispersal of antimicrobial determinants between different bacteria. PMID:22046172

  20. Acquired ciliary circumscribed grey hair (ACCG).

    PubMed

    Romero, A G; Calatayud, J C

    2001-12-01

    Grey-haired areas usually occur due to aging or inheritance. A case is described of abrupt occurrence of a focal circumscribed grey-hair in the eyebrow region (a single hair) in a 27-year-old woman. The phenomenon was named acquired ciliary circumscribed grey-hair (ACCG). Qualitative and semiquantitative findings were obtained by microanalytical studies. In addition to morphological differences from control hair, the ACCG hair showed a high percentage of sulfur (99.8%) and absence of oligoelements.

  1. Rare presentation of spontaneous acquired diaphragmatic hernia.

    PubMed

    Gupta, Shweta; Bali, Roseleen Kaur; Das, Kamanasish; Sisodia, Anula; Dewan, R K; Singla, Rupak

    2011-01-01

    Spontaneous acquired diaphragmatic hernia without any apparent history of trauma is a very rare condition and is very difficult to diagnose. We present a case of a 21-year-old male who presented with abdominal pain for one month and four episodes of vomiting for one day. Clinical suspicion, chest radiography with nasogastric tube in situ and computed tomography (CT) confirmed the diagnosis. The diaphragmatic defect was repaired surgically. The patient had an uneventful post-operative recovery.

  2. The pathophysiology of acquired premature ejaculation.

    PubMed

    McMahon, Chris G; Jannini, Emmanuele A; Serefoglu, Ege C; Hellstrom, Wayne J G

    2016-08-01

    The second Ad Hoc International Society for Sexual Medicine (ISSM) Committee for the Definition of Premature Ejaculation defined acquired premature ejaculation (PE) as a male sexual dysfunction characterized by a the development of a clinically significant and bothersome reduction in ejaculation latency time in men with previous normal ejaculatory experiences, often to about 3 minutes or less, the inability to delay ejaculation on all or nearly all vaginal penetrations, and the presence of negative personal consequences, such as distress, bother, frustration and/or the avoidance of sexual intimacy. The literature contains a diverse range of biological and psychological etiological theories. Acquired PE is commonly due to sexual performance anxiety, psychological or relationship problems, erectile dysfunction (ED), and occasionally prostatitis and hyperthyroidism, consistent with the predominant organic etiology of acquired PE, men with this complaint are usually older, have a higher mean BMI and a greater incidence of comorbid disease including hypertension, sexual desire disorder, diabetes mellitus, chronic prostatitis, and ED compared to lifelong, variable and subjective PE.

  3. The pathophysiology of acquired premature ejaculation

    PubMed Central

    Jannini, Emmanuele A.; Serefoglu, Ege C.; Hellstrom, Wayne J. G.

    2016-01-01

    The second Ad Hoc International Society for Sexual Medicine (ISSM) Committee for the Definition of Premature Ejaculation defined acquired premature ejaculation (PE) as a male sexual dysfunction characterized by a the development of a clinically significant and bothersome reduction in ejaculation latency time in men with previous normal ejaculatory experiences, often to about 3 minutes or less, the inability to delay ejaculation on all or nearly all vaginal penetrations, and the presence of negative personal consequences, such as distress, bother, frustration and/or the avoidance of sexual intimacy. The literature contains a diverse range of biological and psychological etiological theories. Acquired PE is commonly due to sexual performance anxiety, psychological or relationship problems, erectile dysfunction (ED), and occasionally prostatitis and hyperthyroidism, consistent with the predominant organic etiology of acquired PE, men with this complaint are usually older, have a higher mean BMI and a greater incidence of comorbid disease including hypertension, sexual desire disorder, diabetes mellitus, chronic prostatitis, and ED compared to lifelong, variable and subjective PE. PMID:27652216

  4. Polar Environmental Monitoring

    NASA Technical Reports Server (NTRS)

    Nagler, R. G.; Schulteis, A. C.

    1979-01-01

    The present and projected benefits of the polar regions were reviewed and then translated into information needs in order to support the array of polar activities anticipated. These needs included measurement sensitivities for polar environmental data (ice/snow, atmosphere, and ocean data for integrated support) and the processing and delivery requirements which determine the effectiveness of environmental services. An assessment was made of how well electromagnetic signals can be converted into polar environmental information. The array of sensor developments in process or proposed were also evaluated as to the spectral diversity, aperture sizes, and swathing capabilities available to provide these measurements from spacecraft, aircraft, or in situ platforms. Global coverage and local coverage densification options were studied in terms of alternative spacecraft trajectories and aircraft flight paths.

  5. EDITORIAL: Polarization Optics

    NASA Astrophysics Data System (ADS)

    Turunen, Jari; Friesem, Asher A.; Friberg, Ari T.

    2004-03-01

    This special issue on Polarization Optics contains one review article and 23 research papers, many of which are based on presentations at the International Commission for Optics Topical Meeting on Polarization Optics, held in Polvijärvi, Finland, between 30 June and 3 July 2003. While this issue should not in any sense be considered as a `proceedings' of this meeting, the possibility of submitting papers to it was widely advertised during the meeting, which was attended by a large fraction of prominent scientists in the field of polarization optics. Thus the quality of papers in this special issue is high. In announcing both the meeting and this special issue, we emphasized that the concept of `polarization optics' should be understood in a wide sense. In fact, all contributions dealing with the vectorial nature of light were welcome. As a result, the papers included here cover a wide range of different aspects of linear and nonlinear polarization optics. Both theoretical and experimental features are discussed. We are pleased to see that the conference and this special issue both reflect the wide diversity of important and novel polarization phenomena in optics. The papers in this special issue, and other recently published works, demonstrate that even though polarization is a fundamental property of electromagnetic fields, interest in it is rapidly increasing. The fundamental relations between partial coherence and partial polarization are currently under vigorous research in electromagnetic coherence theory. In diffractive optics it has been found that the exploitation of the vectorial nature of light can be of great benefit. Fabrication of sophisticated, spatially variable polarization-control elements is becoming possible with the aid of nanolithography. Polarization singularities and the interplay of bulk properties and topology in nanoscale systems have created much enthusiasm. In nonlinear optics, the second harmonic waves generated on reflection and

  6. 'Mapping' a Changing Earth through the Polar Lens - the USGS Contribution to the International Polar Year

    NASA Astrophysics Data System (ADS)

    Leahy, P. P.

    2005-05-01

    USGS has a long tradition of scientific monitoring, assessment, and research in the polar regions. Beginning with geophysical and geological surveys in the Arctic in the early 1900's and joint work with the National Science Foundation in Antarctica after WWII, the USGS has had an extensive history of diverse activities such as topographic mapping and geodetic control in Antarctica; satellite and ground-based monitoring of glaciers and ice caps; research on movements, distribution patterns, and adaptation of polar wildlife; establishment and operation of a seismic array at the South Pole; estimations of energy resources of the circum-Arctic; mapping the occurrence and distribution of circum-Arctic vegetation; and the development of paleoclimate records from Alaskan sediments and polar ice cores. USGS participation in the 2007 - 2008 International Polar Year effort will both extend and enhance current activities and establish and integrate new activities into large-scale international monitoring and research efforts. We envision these efforts as 'mapping' the Earth in the broadest and most inclusive sense of the word - from mapping earth-system interactions to mapping genomic diversity, and from mapping at the largest scales utilizing remotely-sensed data acquired from satellite-based sensors to the smallest scales utilizing data acquired at the molecular level. By utilizing the full spectrum of USGS capabilities and by partnering with other federal and state agencies, NGOs, universities, and international consortia during IPY, the USGS seeks to be part of the global community that will lead scientific efforts to elucidate current physical, biological and chemical processes that operate in the polar regions and provide the fundamental science that will inform policy, land-use, and resource management decisions in the decades to come.

  7. Spatially resolved refractive index profiles of electrically switchable computer-generated holographic gratings.

    PubMed

    Zito, Gianluigi; Finizio, Andrea; De Nicola, Sergio

    2009-10-12

    We describe a spatially resolved interferometric technique combined with a phase reconstruction method that provides a quantitative two-dimensional profile of the refractive index and spatial distribution of the optical contrast between the on-off states of electrically switchable diffraction gratings as a function of the external electric field. The studied structures are holographic gratings optically written into polymer/liquid crystal composites through single-beam spatial light modulation by means of computer-generated holograms. The electro-optical response of the gratings is also discussed. The diffraction efficiency results to be dependent on the incident light polarization suggesting the possibility to develop polarization dependent switching devices.

  8. Direct observation of spin-resolved full and empty electron states in ferromagnetic surfaces

    SciTech Connect

    Berti, G. Calloni, A.; Brambilla, A.; Bussetti, G.; Duò, L.; Ciccacci, F.

    2014-07-15

    We present a versatile apparatus for the study of ferromagnetic surfaces, which combines spin-polarized photoemission and inverse photoemission spectroscopies. Samples can be grown by molecular beam epitaxy and analyzed in situ. Spin-resolved photoemission spectroscopy analysis is done with a hemispherical electron analyzer coupled to a 25 kV-Mott detector. Inverse photoemission spectroscopy experiments are performed with GaAs crystals as spin-polarized electron sources and a UV bandpass photon detector. As an example, measurements on the oxygen passivated Fe(100)-p(1×1)O surface are presented.

  9. Spatially Resolved Mapping of Disorder Type and Distribution in Random Systems using Artificial Neural Network Recognition

    SciTech Connect

    Jesse, Stephen; Kalinin, Sergei V; Kumar, Amit; Ovchinnikov, Oleg S; Guo, Senli; Griggio, Flavio; Trolier-Mckinstry, Susan E

    2011-01-01

    The spatial variability of the polarization dynamics in thin film ferroelectric capacitors was probed by recognition analysis of spatially-resolved spectroscopic data. Switching spectroscopy piezoresponse force microscopy was used to measure local hysteresis loops and map them on a 2D random-bond, random-field Ising model. A neural-network based recognition approach was utilized to analyze the hysteresis loops and their spatial variability. Strong variability is observed in the polarization dynamics around macroscopic cracks due to the modified local elastic and electric boundary conditions, with most pronounced effect on the length scale of ~100 nm away from the crack.

  10. Axon selection: From a polarized cytoplasm to a migrating neuron.

    PubMed

    de Anda, Froylan Calderon; Tsai, Li-Huei

    2011-05-01

    The shape of a neuron supplies valuable clues as to its function. Neurons typically extend a single long, thin axon, which will transmit signals and several shorter and thicker dendrites, which will receive signals. The understanding of the means by which neurons acquire a polarized morphology is a fundamental issue in developmental neurobiology. The current view suggests that axon selection involves a stochastic mechanism. However, new data suggest that a polarized cytoplasm not only determines the position of neurite emergence, but also sets the conditions for morphological polarization. In vertebrates, neurons migrate before establishing their final morphology. Recent work shows that the polarized cytoplasm also determines how neurons migrate. Thus, neuronal migration might influence the processes by which neurons form an axon.

  11. Time and Space Resolved Heat Flux Measurements During Nucleate Boiling with Constant Heat Flux Boundary Conditions

    NASA Technical Reports Server (NTRS)

    Yerramilli, Vamsee K.; Myers, Jerry G.; Hussey, Sam W.; Yee, Glenda F.; Kim, Jungho

    2005-01-01

    The lack of temporally and spatially resolved measurements under nucleate bubbles has complicated efforts to fully explain pool-boiling phenomena. The objective of this current work was to acquire time and space resolved temperature distributions under nucleating bubbles on a constant heat flux surface using a microheater array with 100x 100 square microns resolution, then numerically determine the wall to liquid heat flux. This data was then correlated with high speed (greater than l000Hz) visual recordings of The bubble growth and departure from the heater surface acquired from below and from the side of the heater. The data indicate that microlayer evaporation and contact line heat transfer are not major heat transfer mechanisms for bubble growth. The dominant heat transfer mechanism appears to be transient conduction into the liquid as the liquid rewets the wall during the bubble departure process.

  12. 48 CFR 1845.502-70 - Contractor-acquired property.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 48 Federal Acquisition Regulations System 6 2010-10-01 2010-10-01 true Contractor-acquired... Possession of Contractors 1845.502-70 Contractor-acquired property. All contractor-acquired property must be... contractor-acquired. (2) Submission of DD Form 1419, DOD Industrial Plant Requisition, or equivalent...

  13. Active polarization descattering.

    PubMed

    Treibitz, Tali; Schechner, Yoav Y

    2009-03-01

    Vision in scattering media is important but challenging. Images suffer from poor visibility due to backscattering and attenuation. Most prior methods for scene recovery use active illumination scanners (structured and gated), which can be slow and cumbersome, while natural illumination is inapplicable to dark environments. The current paper addresses the need for a non-scanning recovery method, that uses active scene irradiance. We study the formation of images under widefield artificial illumination. Based on the formation model, the paper presents an approach for recovering the object signal. It also yields rough information about the 3D scene structure. The approach can work with compact, simple hardware, having active widefield, polychromatic polarized illumination. The camera is fitted with a polarization analyzer. Two frames of the scene are taken, with different states of the analyzer or polarizer. A recovery algorithm follows the acquisition. It allows both the backscatter and the object reflection to be partially polarized. It thus unifies and generalizes prior polarization-based methods, which had assumed exclusive polarization of either of these components. The approach is limited to an effective range, due to image noise and illumination falloff. Thus, the limits and noise sensitivity are analyzed. We demonstrate the approach in underwater field experiments.

  14. Polar Warming Drivers

    NASA Astrophysics Data System (ADS)

    McDunn, T. L.; Bougher, S. W.; Mischna, M. A.; Murphy, J. R.

    2012-12-01

    Polar warming is a dynamically induced temperature enhancement over mid-to-high latitudes that results in a reversed (poleward) meridional temperature gradient. This phenomenon was recently characterized over the 40-90 km altitude region [1] based on nearly three martian years of Mars Climate Sounder observations [2, 3]. Here we investigate which forcing mechanisms affect the magnitude and distribution of the observed polar warming by conducting simulations with the Mars Weather Research and Forecasting General Circulation Model [4, 5]. We present simulations confirming the influence topography [6] and dust loading [e.g., 7] have upon polar warming. We then present simulations illustrating the modulating influence gravity wave momentum deposition exerts upon polar warming, consistent with previous modeling studies [e.g., 8]. The results of this investigation suggest the magnitude and distribution of polar warming in the martian middle atmosphere is modified by gravity wave activity and that the characteristics of the gravity waves that most significantly affect polar warming vary with season. References: [1] McDunn, et al., 2012 (JGR), [2]Kleinböhl, et al., 2009 (JGR), [3] Kleinböhl, et al., 2011 (JQSRT), [4] Richardson, et al., 2007 (JGR), [5] Mischna, et al., 2011 (Planet. Space Sci.), [6] Richardson and Wilson, 2002 (Nature), [7] Haberle, et al., 1982 (Icarus), [8] Barnes, 1990 (JGR).

  15. Nanosecond-resolved temperature measurements using magnetic nanoparticles.

    PubMed

    Xu, Wenbiao; Liu, Wenzhong; Zhang, Pu

    2016-05-01

    Instantaneous and noninvasive temperature measurements are important when laser thermotherapy or welding is performed. A noninvasive nanosecond-resolved magnetic nanoparticle (MNP) temperature measurement system is described in which a transient change in temperature causes an instantaneous change in the magnetic susceptibilities of the MNPs. These transient changes in the magnetic susceptibilities are rapidly recorded using a wideband magnetic measurement system with an upper frequency limit of 0.5 GHz. The Langevin function (the thermodynamic model characterizing the MNP magnetization process) is used to obtain the temperature information. Experiments showed that the MNP DC magnetization temperature-measurement system can detect a 14.4 ns laser pulse at least. This method of measuring temperature is likely to be useful for acquiring the internal temperatures of materials irradiated with lasers, as well as in other areas of research.

  16. Ellipticity-tunable attosecond XUV pulse generation with a rotating bichromatic circularly polarized laser field.

    PubMed

    Zhang, Xiaofan; Zhu, Xiaosong; Liu, Xi; Wang, Dian; Zhang, Qingbin; Lan, Pengfei; Lu, Peixiang

    2017-03-15

    We propose and theoretically demonstrate a method to generate attosecond XUV pulses with tunable ellipticity from aligned molecules irradiated by a bichromatic counterrotating circularly polarized (BCCP) driving laser field. By rotating the BCCP field, the attoseond XUV pulse varies from being left elliptically polarized to right elliptically polarized. The rotation of the BCCP field can be easily achieved by adjusting the relative phases between the two circularly polarized components. This scheme will benefit a broad range of applications, including the exploration of chiral-sensitive properties of the light-matter interaction and time-resolved imaging of magnetic structures.

  17. Exploring Cosmic X-ray Source Polarization

    NASA Technical Reports Server (NTRS)

    Swank, Jean Hebb; Jahodal, K.; Kallman, T. R.; Kaaret, P.

    2008-01-01

    Cosmic X-ray sources are expected to be polarized, either because of their asymmetry and the role of scattering in their emission or the role of magnetic fields. Polarization at other wavelengths has been useful. X-ray polarization will provide a new handle on black hole parameters, in particular the spin, on accretion flows and outflows, on neutron star spin orientations and emission mechanisms, on the quantum mechanical effects of super-strong magnetic fields of magnetars, and on the structure of supernovae shocks. The proposed Gravity and Extreme Magnetism SMEX (GEMS) will use high efficiency polarimeters behind thin foil mirrors. The statistical sensitivity and control of systematics will allow measurement of polarization fractions as small as 1% from many galactic and extragalactic sources. Targets which should be polarized at the level that GEMS can easily measure include stellar black holes, Seyfert galaxies and quasars, blazars, rotation-powered and accretion-powered pulsars, magnetars, shell supernova remnants and pulsar wind nebulae. The polarimeters are Time Projection Chambers that allow reconstruction of images of photoelectron tracks for 2-10 keV Xrays. They can be deep without sacrificing modulation. These polarimeters do not image the sky, but the telescope point spread function and detector collimation allow structure to be resolved at the 10 arcmin level. Rotation of the spacecraft is not needed for the signal measurement in the Time Projection Chambers, but provides for measurement and correction of systematic errors. It also allows a small Bragg reflection soft X-ray experiment to be included that can be used for isolated neutron stars and blazars.

  18. Design, testing, and clinical studies of a handheld polarized light camera.

    PubMed

    Ramella-Roman, Jessica C; Lee, Ken; Prahl, Scott A; Jacques, Steven L

    2004-01-01

    Polarized light imaging has been used to detect the borders of skin cancer and facilitate assessment of cancer boundaries. A design for an inexpensive handheld polarized camera is presented and clinical images acquired with this prototype are shown. The camera is built with two universal serial bus (USB) color video cameras, a polarizing beamsplitter cube, and a 4x objective lens. Illumination is provided by three white LEDs and a sheet polarizer. Horizontal and vertical linearly polarized reflected images are processed at 7 frames/s and a resulting polarized image is displayed on screen. We compare the performances of cheap USB camera and a 16-bit electronically cooled camera. Dark noise and image repeatability are compared. In both cases, the 16-bit camera outperforms the USB cameras. Despite these limitations, the results obtained with this USB prototype are very satisfactory. Examples of polarized images of lesions taken prior to surgery are presented.

  19. Polarized Light Microscopy

    NASA Technical Reports Server (NTRS)

    Frandsen, Athela F.

    2016-01-01

    Polarized light microscopy (PLM) is a technique which employs the use of polarizing filters to obtain substantial optical property information about the material which is being observed. This information can be combined with other microscopy techniques to confirm or elucidate the identity of an unknown material, determine whether a particular contaminant is present (as with asbestos analysis), or to provide important information that can be used to refine a manufacturing or chemical process. PLM was the major microscopy technique in use for identification of materials for nearly a century since its introduction in 1834 by William Fox Talbot, as other techniques such as SEM (Scanning Electron Microscopy), FTIR (Fourier Transform Infrared spectroscopy), XPD (X-ray Powder Diffraction), and TEM (Transmission Electron Microscopy) had not yet been developed. Today, it is still the only technique approved by the Environmental Protection Agency (EPA) for asbestos analysis, and is often the technique first applied for identification of unknown materials. PLM uses different configurations in order to determine different material properties. With each configuration additional clues can be gathered, leading to a conclusion of material identity. With no polarizing filter, the microscope can be used just as a stereo optical microscope, and view qualities such as morphology, size, and number of phases. With a single polarizing filter (single polars), additional properties can be established, such as pleochroism, individual refractive indices, and dispersion staining. With two polarizing filters (crossed polars), even more can be deduced: isotropy vs. anisotropy, extinction angle, birefringence/degree of birefringence, sign of elongation, and anomalous polarization colors, among others. With the use of PLM many of these properties can be determined in a matter of seconds, even for those who are not highly trained. McCrone, a leader in the field of polarized light microscopy, often

  20. Polarization Signatures of Bow Shocks in Stellar Winds

    NASA Astrophysics Data System (ADS)

    Shrestha, M.; Hoffman, J. L.

    2015-12-01

    Bow shocks around massive stars provide important information regarding the motion of the star, the stellar wind properties, and the density of the surrounding interstellar medium. We use a Monte Carlo radiative transfer code to investigate the polarization created when photons from a central star scatter from electrons or dust grains in a surrounding bow shock. We discuss the behavior of the polarization with respect to viewing angle as a function of parameters such as optical depth and scattering medium in both the resolved and unresolved cases.

  1. Helping You Buy: Link Resolver Tools

    ERIC Educational Resources Information Center

    Singer, Ross

    2006-01-01

    To any library with an electronic collection of any significance, the OpenURL link resolver has (or should) become an indispensable service for helping its users retrieve full text from citations. Although they are a relatively new technology (in library terms, at any rate), link resolvers arguably have become as important as the OPAC; they locate…

  2. Spectrally resolved motional Stark effect measurements on ASDEX Upgrade

    SciTech Connect

    Reimer, R.; Dinklage, A.; Wolf, R.; Fischer, R.; Hobirk, J.; Löbhard, T.; Mlynek, A.; Reich, M.; Sawyer, L.; Collaboration: ASDEX Upgrade

    2013-11-15

    A spectrally resolved Motional Stark Effect (MSE) diagnostic has been installed at ASDEX Upgrade. The MSE data have been fitted by a forward model providing access to information about the magnetic field in the plasma interior [R. Reimer, A. Dinklage, J. Geiger et al., Contrib. Plasma Phys. 50, 731–735 (2010)]. The forward model for the beam emission spectra comprises also the fast ion D{sub α} signal [W. W. Heidbrink and G. J. Sadler, Nucl. Fusion 34, 535–615 (1994)] and the smearing on the CCD-chip. The calculated magnetic field data as well as the revealed (dia)magnetic effects are consistent with the results from equilibrium reconstruction solver. Measurements of the direction of the magnetic field are affected by unknown and varying polarization effects in the observation.

  3. Depth-resolved magnetization reversal in nanoporous perpendicular anisotropy multilayers

    NASA Astrophysics Data System (ADS)

    Kirby, B. J.; Rahman, M. T.; Dumas, R. K.; Davies, J. E.; Lai, C. H.; Liu, Kai

    2013-01-01

    We have used polarized neutron reflectometry to study the field-dependent magnetizations of Co/Pt mulitlayers patterned via deposition onto nanoporous alumina hosts with varying pore aspect ratio. Despite the porosity and lack of long-range order, robust spin-dependent reflectivities are observed, allowing us to distinguish the magnetization of the surface multilayer from that of material in the pores. We find that as the pores become wider and shallower, the surface Co/Pt multilayers have progressively smaller high field magnetization and exhibit softer magnetic reversal—consistent with increased magnetic disorder and a reduction of the perpendicular anisotropy near the pore rims. These results reveal complexities of magnetic order in nanoporous heterostructures, and help pave the way for depth-resolved studies of complex magnetic heterostructures grown on prepatterned substrates.

  4. A Comparison of Kinematic and Photometric Inclinations in the RESOLVE Survey

    NASA Astrophysics Data System (ADS)

    Beauchemin, Ryan William; Kannappan, Sheila; Eckert, Kathleen D.; Hoversten, Erik A.; Hall, Kirsten; Resolve

    2015-01-01

    Using standard prescriptions relating axial ratios to inclinations, the inferred distribution of inclinations for galaxies in the REsolved Spectroscopy Of a Local VolumE (RESOLVE) survey departs from theoretical expectations for a complete volume-limited sample. We compare kinematic inclinations from velocity fields of ˜200 disk galaxies in RESOLVE with their respective photometric inclinations to examine the origin of this discrepancy. We further investigate which galaxy properties may correlate with differences between inclination estimates, considering morphology, mass, optical size, and rotation curve asymmetry. Our test sample spans galaxy masses between 109 and 1011 M⊙, axial ratios between 0.2 and 0.9, rotation curve asymmetries between 0% and 30%, and the full range of morphological types, which are representative of the distribution for the parent survey, RESOLVE. However, the test sample does not represent the optically largest or smallest galaxies in RESOLVE, denoted by 90% r-band light radii greater than 70" or less than 6". The kinematic data for our sample galaxies were acquired with our custom image slicer on the SOAR telescope/Goodman spectrograph, and inclinations were measured using DiskFit. This analysis will contribute to the RESOLVE kinematic database in preparation. This research was supported by the National Science Foundation under an REU supplement to CAREER award AST-0955368.

  5. Angle-resolved PED and AED calculations for different structures of the diamond C(111) surface

    NASA Astrophysics Data System (ADS)

    Niebergall, L.; Rennert, P.; Chassé, A.; Kucherenko, Yu

    1998-05-01

    Angle-resolved (AR) photoelectron diffraction (PED) spectra for electrons excited from the C 1s core state and angle-resolved KVV Auger electron diffraction (AED) spectra are calculated for the Pandey and the Tsai stucture models of diamond C(111) which extend previous investigations of the ideal structure. It is shown how to decide on the structure model by comparing PE spectra for different directions and by comparing PED and AED spectra. Calculations have been performed by evaluating the scattering path operator for a finite cluster in a curved-wave approximation. The different matrix elements for the photoelectron excitation and for the Auger process, respectively, are included. It is shown that the PED intensities are very sensitive to the surface reconstruction for polar angles in the range of 80°. In the AED intensities, polar scans in the plane perpendicular to the chain direction can be considered.

  6. Polar Vortices in Shallow Water Simulations of Gas Giants

    NASA Astrophysics Data System (ADS)

    O'Neill, Morgan E.; Emanuel, Kerry

    2014-11-01

    Jupiter, Saturn and Neptune each exhibit unique polar atmospheric behavior. Assuming these flows are due to shallow dynamics, we explore the parameter space potentially responsible for the difference between each planet's polar features. The best observations have come from the Cassini misson to Saturn. Among many discoveries, a massive, warm and cyclonic vortex has been observed on each pole. The South Polar Vortex (SPV), specifically, has the highest measured temperatures on Saturn, a double eyewall, deep eye and a rapid cyclonic jet with the second highest windspeeds observed on the planet. Numerous small, vortical, and potentially convective systems are embedded within the large-scale flow of the SPV. Given these observations, we explore one potential mechanism of polar vortex maintenance: up-scale, poleward vorticity flux due to vortical hot towers (VHTs). Large GCMs cannot yet resolve local deep convection in the weather layer. Using a reduced gravity shallow water model on a polar beta plane, we represent convective towers with mass-flux driven vortex pairs and allow them to move freely. We show that there exist multiple regimes of polar flow, and that small and/or quickly rotating planets with sufficient total energy favor a polar cyclone in our simulations.

  7. [Polar and non polar notations of refraction].

    PubMed

    Touzeau, O; Gaujoux, T; Costantini, E; Borderie, V; Laroche, L

    2010-01-01

    Refraction can be expressed by four polar notations which correspond to four different combinations of spherical or cylindrical lenses. Conventional expressions of refraction (plus and minus cylinder notation) are described by sphere, cylinder, and axis. In the plus cylinder notation, the axis visualizes the most powerful meridian. The axis usually corresponds to the bow tie axis in curvature maps. Plus cylinder notation is also valuable for all relaxing procedures (i.e., selective suture ablation, arcuate keratotomy, etc.). In the cross-cylinder notation, two orthogonal cylinders can describe (without the sphere component) the actual refraction of both the principal meridians. This notation must be made before performing the vertex calculation. Using an association of a Jackson cross-cylinder and a spherical equivalent, refraction can be broken down into two pure components: astigmatism and sphere. All polar notations of refraction may perfectly characterize a single refraction but are not suitable for statistical analysis, which requires nonpolar expression. After doubling the axis, a rectangular projection breaks down the Jackson cross-cylinder, which has a polar axis, into two Jackson cross-cylinders on the 0 degrees /90 degrees and 45 degrees /135 degrees axis. This procedure results in the loss of the directional nature of the data. Refraction can be written in a nonpolar notation by three rectangular coordinates (x,y,z), which can also represent the spherocylinder by one point in a dioptric space. These three independent (orthogonal) variables have a concrete optical significance: a spherical component, a direct/inverse (WTR/ATR) component, and an oblique component of the astigmatism. Finally, nonpolar notations are useful for statistical analysis and graphical representation of refraction.

  8. When measured spin polarization is not spin polarization

    NASA Astrophysics Data System (ADS)

    Dowben, P. A.; Wu, Ning; Binek, Christian

    2011-05-01

    Spin polarization is an unusually ambiguous scientific idiom and, as such, is rarely well defined. A given experimental methodology may allow one to quantify a spin polarization but only in its particular context. As one might expect, these ambiguities sometimes give rise to inappropriate interpretations when comparing the spin polarizations determined through different methods. The spin polarization of CrO2 and Cr2O3 illustrate some of the complications which hinders comparisons of spin polarization values.

  9. When measured spin polarization is not spin polarization.

    PubMed

    Dowben, P A; Wu, Ning; Binek, Christian

    2011-05-04

    Spin polarization is an unusually ambiguous scientific idiom and, as such, is rarely well defined. A given experimental methodology may allow one to quantify a spin polarization but only in its particular context. As one might expect, these ambiguities sometimes give rise to inappropriate interpretations when comparing the spin polarizations determined through different methods. The spin polarization of CrO(2) and Cr(2)O(3) illustrate some of the complications which hinders comparisons of spin polarization values.

  10. Polarized nuclear target based on parahydrogen induced polarization

    SciTech Connect

    D. Budker, M.P. Ledbetter, S. Appelt, L.S. Bouchard, B. Wojtsekhowski

    2012-12-01

    We discuss a novel concept of a polarized nuclear target for accelerator fixed-target scattering experiments, which is based on parahydrogen induced polarization (PHIP). One may be able to reach a 33% free-proton polarization in the ethane molecule. The potential advantages of such a target include operation at zero magnetic field, fast ({approx}100 HZ) polarization oscillation (akin to polarization reversal), and operation with large intensity of an electron beam.

  11. Polar low dynamics

    SciTech Connect

    Montgomery, M.T.; Farrell, B.F. )

    1992-12-15

    Polar lows are intense subsynoptic-scale cyclones that form over high-latitude oceans in association with deep cumulus convection and strong ambient baroclinicity. Recent observations indicate that polar lows are generally initiated by a nonaxisymmetric interaction between a surface disturbance and an upper-level mobile trough. Extant theories of polar low formation preclude study of such a process since they either constrain their models to be axisymmetric, or do not explicitly account for his transient interaction. In this work the physics of interacting upper- and lower-level potential vorticity structures is studied as an initial-value problem using a three-dimensional nonlinear geostrophic momentum model that incorporates moist processes and includes strong baroclinic dynamics. Model results illustrate the rapid formation of an intense small-scale cyclone whose structure is consistent with observations of mature polar lows. A conceptual model of polar low development is proposed. In the first stage of development, called induced self-development, a mobile upper trough initiates a rapid low-level spinup due to the enhanced omega response in a conditionally neutral baroclinic atmosphere. A secondary development follows, called diabatic destabilization, that is associated with the production of low-level potential vorticity by diabatic processes. Diabatic destabilization represents a simple mechanism for maintaining the intensity of polar lows until they reach land. In exceptional instances of negligible upper-level forcing, the latter may also describe the gradual intensification of small-scale cyclones in regions of sustained neutrality and surface baroclinicity. Ideas regarding polar low equilibration and prospects for a unified theory of arctic and midlatitude cyclones are discussed. 75 refs., 4 figs., 1 tab.

  12. The Utilization of Spin Polarized Photoelectron Spectroscopy as a Probe of Electron Correlation with an Ultimate Goal of Pu

    SciTech Connect

    Tobin, J G; Yu, S W; Chung, B W; Morton, S A; Komesu, T; Waddill, G D

    2008-02-07

    We are developing the technique of spin-polarized photoelectron spectroscopy as a probe of electron correlation with the ultimate goal of resolving the Pu electronic structure controversy. Over the last several years, we have demonstrated the utility of spin polarized photoelectron spectroscopy for determining the fine details of the electronic structure in complex systems such as those shown in this report.

  13. The Utilization of Spin Polarized Photoelectron Spectroscopy as a Probe of Electron Correlation with an Ultimate Goal of Pu

    SciTech Connect

    Tobin, James; Yu, Sung; Chung, Brandon; Morton, Simon; Komesu, Takashi; Waddill, George

    2008-02-11

    We are developing the technique of spin-polarized photoelectron spectroscopy as a probe of electron correlation with the ultimate goal of resolving the Pu electronic structure controversy. Over the last several years, we have demonstrated the utility of spin polarized photoelectron spectroscopy for determining the fine details of the electronic structure in complex systems such as those shown in the paper.

  14. Spin-polarized Auger electrons

    NASA Astrophysics Data System (ADS)

    Merz, H.; Semke, J.

    1990-12-01

    The spin polarization of Auger electrons will be discussed within the standard two-step model of the Auger emission process for different situations: target polarized, projectile polarized, targe and projectile unpolarized. In these three cases different interaction mechanisms are responsible for the polarization of the emitted Auger electrons. The present theoretical and experimental situation will be reviewed.

  15. Sequential Polarity-Reversing Circuit

    NASA Technical Reports Server (NTRS)

    Labaw, Clayton C.

    1994-01-01

    Proposed circuit reverses polarity of electric power supplied to bidirectional dc motor, reversible electro-mechanical actuator, or other device operating in direction depending on polarity. Circuit reverses polarity each time power turned on, without need for additional polarity-reversing or direction signals and circuitry to process them.

  16. Acquired prosopagnosia without word recognition deficits.

    PubMed

    Susilo, Tirta; Wright, Victoria; Tree, Jeremy J; Duchaine, Bradley

    2015-01-01

    It has long been suggested that face recognition relies on specialized mechanisms that are not involved in visual recognition of other object categories, including those that require expert, fine-grained discrimination at the exemplar level such as written words. But according to the recently proposed many-to-many theory of object recognition (MTMT), visual recognition of faces and words are carried out by common mechanisms [Behrmann, M., & Plaut, D. C. ( 2013 ). Distributed circuits, not circumscribed centers, mediate visual recognition. Trends in Cognitive Sciences, 17, 210-219]. MTMT acknowledges that face and word recognition are lateralized, but posits that the mechanisms that predominantly carry out face recognition still contribute to word recognition and vice versa. MTMT makes a key prediction, namely that acquired prosopagnosics should exhibit some measure of word recognition deficits. We tested this prediction by assessing written word recognition in five acquired prosopagnosic patients. Four patients had lesions limited to the right hemisphere while one had bilateral lesions with more pronounced lesions in the right hemisphere. The patients completed a total of seven word recognition tasks: two lexical decision tasks and five reading aloud tasks totalling more than 1200 trials. The performances of the four older patients (3 female, age range 50-64 years) were compared to those of 12 older controls (8 female, age range 56-66 years), while the performances of the younger prosopagnosic (male, 31 years) were compared to those of 14 younger controls (9 female, age range 20-33 years). We analysed all results at the single-patient level using Crawford's t-test. Across seven tasks, four prosopagnosics performed as quickly and accurately as controls. Our results demonstrate that acquired prosopagnosia can exist without word recognition deficits. These findings are inconsistent with a key prediction of MTMT. They instead support the hypothesis that face

  17. Motor Oil Classification Based on Time-Resolved Fluorescence

    PubMed Central

    Mu, Taotao; Chen, Siying; Zhang, Yinchao; Guo, Pan; Chen, He; Meng, Fandong

    2014-01-01

    A time-resolved fluorescence (TRF) technique is presented for classifying motor oils. The system is constructed with a third harmonic Nd:YAG laser, a spectrometer, and an intensified charge coupled device (ICCD) camera. Steady-state and time-resolved fluorescence (TRF) measurements are reported for several motor oils. It is found that steady-state fluorescence is insufficient to distinguish the motor oil samples. Then contour diagrams of TRF intensities (CDTRFIs) are acquired to serve as unique fingerprints to identify motor oils by using the distinct TRF of motor oils. CDTRFIs are preferable to steady-state fluorescence spectra for classifying different motor oils, making CDTRFIs a particularly choice for the development of fluorescence-based methods for the discrimination and characterization of motor oils. The two-dimensional fluorescence contour diagrams contain more information, not only the changing shapes of the LIF spectra but also the relative intensity. The results indicate that motor oils can be differentiated based on the new proposed method, which provides reliable methods for analyzing and classifying motor oils. PMID:24988439

  18. RESOLVE Mission Architecture for Lunar Resource Prospecting and Utilization

    NASA Technical Reports Server (NTRS)

    George, J. A.; Mattes, G. W.; Rogers, K. N.; Magruder, D. F.; Paz, A. J.; Vaccaro, H. M.; Baird, R. S.; Sanders, G. B.; Smith, J. T.; Quinn, J. W.; Larson, W. E.; Colaprete, A.; Elphic, R. C.; Suaris, T. R.

    2012-01-01

    Design Reference Mission (DRM) evaluations were performed for The Regolith & Environment Science, and Oxygen & Lunar Volatile Extraction (RESOLVE) project to determine future flight mission feasibility and understand potential mission environment impacts on hardware requirements, science/resource assessment objectives, and mission planning. DRM version 2.2 (DRM 2.2) is presented for a notional flight of the RESOLVE payload for lunar resource ground truth and utilization (Figure 1) [1]. The rover/payload deploys on a 10 day surface mission to the Cabeus crater near the lunar south pole in May of 2016. A drill, four primary science instruments, and a high temperature chemical reactor will acquire and characterize water and other volatiles in the near sub-surface, and perform demonstrations of In-Situ Re-source Utilization (ISRU). DRM 2.2 is a reference point, and will be periodically revised to accommodate and incorporate changes to project approach or implementation, and to explore mission alternatives such as landing site or opportunity.

  19. [Iris heterochromia in acquired Horner's syndrome].

    PubMed

    Beynat, J; Soichot, P; Bidot, S; Dugas, B; Creuzot-Garcher, C; Bron, A

    2007-09-01

    Horner's syndrome (HS) is related to an interruption of the oculosympathetic nerve pathway. The classic clinical findings associated with this condition are ptosis, miosis, and enophthalmos. Heterochromia is typically described in congenital HS, but it is an uncommon finding in acquired HS. We report a case of post-traumatic HS associated with heterochromia. A literature review indicates that this type of heterochromia may be related to a reduction in the number of iris melanocytes. This mechanism may be the same in the physiological iris color modifications in adulthood.

  20. [Acquired immunodeficiency syndrome in pediatric patients].

    PubMed

    Molina Moguel, J L; Ruiz Illezcas, R; Forsbach Sánchez, S; Carreño Alvarez, S; Picco Díaz, I

    1990-12-01

    The object of this study was to determine how many of the patients treated at the Pediatric Odontology Clinic, a branch of the Maxillo-Facial Surgery Service at the Veinte de Noviembre Regional Hospital, ISSSTE, are VIH-positive of show serious manifestations of Acquired Immuno-Deficiency Syndrome (AIDS). For such purpose, 100 pediatric patients suffering from different systemic or local diseases were evaluated, the most common being hematological alterations. Results evidenced the presence of VIH in the blood of five of the pediatric subjects, all suffering from Hemophilia.

  1. Origins of species: acquired genomes and individuality

    NASA Technical Reports Server (NTRS)

    Margulis, L.

    1993-01-01

    Entire genomes with their accompanying protein synthetic systems are transferred throughout the biosphere primarily as bacteria and protists which become symbionts as they irreversibly integrate into pre-existing organisms to form more complex individuals. Individualization is stabilized by simultaneous transmission of once-separate heterologous genetic systems. The origin of new species is hypothesized to correlate with the acquisition, integration and subsequent inheritance of such acquired microbial genomes. These processes were recognized by Mereschkovsky ("Symbiogenesis" in Russian, 1909) and by Wallin ("Symbionticism", see p. 181, this issue).

  2. Common acquired causes of thrombosis in children.

    PubMed

    Tolbert, Jaszianne; Carpenter, Shannon L

    2013-08-01

    Compared to adults, venous thromboembolism in the pediatric population is a rare event. Cancer, cardiac disease, antiphospholipid antibodies, and indwelling catheters are established risk factors for thromboembolism in children. We examined the literature related to thrombophilia in children, childhood cancer and thrombosis, cardiac disease and thrombosis, and antiphospholipid antibody syndrome in children. Citations in identified articles yielded additional articles for review. We found that studies of acquired thrombophilia in children are limited. Current treatment for thromboembolism in children is based on adult data therefore optimal treatment in this population remains unclear.

  3. Acquired Congenital Malalignment of the Great Toenails

    PubMed Central

    Decker, Ashley; Scher, Richard K.; Avarbock, Andrew

    2016-01-01

    Congenital malalignment is the lateral deviation of the nail plate along the longitudinal axis due to the lateral rotation of the nail matrix. The nail plate grows out in ridges caused by repeated microtrauma to the nail. Common complications include onychomycosis, Pseudomonas infection and acute or chronic paronychia. Treatment options range from conservative management to surgical options including realignment and nail matrixectomy. Congenital malalignment usually presents in infancy or childhood, but we present two cases of acquired malalignment occurring in the teenage years. PMID:27171597

  4. Computational polarization difference underwater imaging based on image fusion

    NASA Astrophysics Data System (ADS)

    Han, Hongwei; Zhang, Xiaohui; Guan, Feng

    2016-01-01

    Polarization difference imaging can improve the quality of images acquired underwater, whether the background and veiling light are unpolarized or partial polarized. Computational polarization difference imaging technique which replaces the mechanical rotation of polarization analyzer and shortens the time spent to select the optimum orthogonal ǁ and ⊥axes is the improvement of the conventional PDI. But it originally gets the output image by setting the weight coefficient manually to an identical constant for all pixels. In this paper, a kind of algorithm is proposed to combine the Q and U parameters of the Stokes vector through pixel-level image fusion theory based on non-subsample contourlet transform. The experimental system built by the green LED array with polarizer to illuminate a piece of flat target merged in water and the CCD with polarization analyzer to obtain target image under different angle is used to verify the effect of the proposed algorithm. The results showed that the output processed by our algorithm could show more details of the flat target and had higher contrast compared to original computational polarization difference imaging.

  5. Polarization twist in perovskite ferrielectrics

    PubMed Central

    Kitanaka, Yuuki; Hirano, Kiyotaka; Ogino, Motohiro; Noguchi, Yuji; Miyayama, Masaru; Moriyoshi, Chikako; Kuroiwa, Yoshihiro

    2016-01-01

    Because the functions of polar materials are governed primarily by their polarization response to external stimuli, the majority of studies have focused on controlling polar lattice distortions. In some perovskite oxides, polar distortions coexist with nonpolar tilts and rotations of oxygen octahedra. The interplay between nonpolar and polar instabilities appears to play a crucial role, raising the question of how to design materials by exploiting their coupling. Here, we introduce the concept of ‘polarization twist’, which offers enhanced control over piezoelectric responses in polar materials. Our experimental and theoretical studies provide direct evidence that a ferrielectric perovskite exhibits a large piezoelectric response because of extended polar distortion, accompanied by nonpolar octahedral rotations, as if twisted polarization relaxes under electric fields. The concept underlying the polarization twist opens new possibilities for developing alternative materials in bulk and thin-film forms. PMID:27586824

  6. Artificial polarization components

    NASA Astrophysics Data System (ADS)

    Cescato, L.; Gluch, Ekkehard; Stork, Wilhelm; Streibl, Norbert

    1990-07-01

    High frequency surface relief structures are optically anisotropic and show interesting polarisation properties 1 . These properties can be used to produce polarizations components such as wave plates polarizers. polarizing beamsplitters etc. Our experimental results show that even gratings with relatively low spatial frequency ( periods A ) exhibit a strong phase retardation and can be used as quarter-wave plates. k INTRODUC11ON The artificial birefringence exhibited by ultrahigh frequency gratings of dielectric materials can be used to produce various polarization components2 . Such components have applications in integrated optics as well as in free space optics. In order to produce the high spatial frequencies complex processes such as electron-beam lithography and reactive ion etching are needed. We show in this paper that sinusoidal holographic gratings in photoresist exhibit also a strong phase ret even at relatively long periods. L EXPERIMENTAL MEASUREMENTS To obtain the phase retardation of a lower frequency ( period A ) grating a simple setup as used by Enger and 2 can be applied. In our case however there are three measurements necessary to obtain the phase retardation because transmission of the two perpendicularly polarized beams is different from each other. I GRATING PRODUCTION grating 2 3 4 5 6 7 8 9 period (pmj 0. 74 0. 74 0. 61 0. 54 0. 46 0. 32 0. 54 0. 54 0. 54 ne (sec) 60

  7. Polarized protons at RHIC

    SciTech Connect

    Makdisi, Y.

    1992-01-01

    The approval for construction of the Relativistic Heavy Ion Collider (RHIC) provides a potential opportunity to collide polarized proton beams at energies up to 500 GeV in the center of mass and high luminosities approaching 2 {times} 10{sup 32}/cm{sup 2}/sec. This capability is enhanced by the fact that the AGS has already accelerated polarized protons and relies on the newly completed Accumulator/Booster for providing the required polarized proton intensity and a system of spin rotators (Siberian snakes) to retain the polarization. The RHIC Spin Collaboration was formed and submitted a Letter of Intent to construct this polarized collider capability and utilize its physics opportunities. In this presentation, I will discuss the plans to upgrade the AGS, the proposed layout of the RHIC siberian snakes, and timetables. The physics focus is the measurement of the spin dependent parton distributions with such accessible probes including high p(t) jets, direct photons, and Drell Yan. The attainable sensitivities and the progress that has been reached in defining the detector requirements will be outlined.

  8. Polarized protons at RHIC

    SciTech Connect

    Makdisi, Y.

    1992-10-01

    The approval for construction of the Relativistic Heavy Ion Collider (RHIC) provides a potential opportunity to collide polarized proton beams at energies up to 500 GeV in the center of mass and high luminosities approaching 2 {times} 10{sup 32}/cm{sup 2}/sec. This capability is enhanced by the fact that the AGS has already accelerated polarized protons and relies on the newly completed Accumulator/Booster for providing the required polarized proton intensity and a system of spin rotators (Siberian snakes) to retain the polarization. The RHIC Spin Collaboration was formed and submitted a Letter of Intent to construct this polarized collider capability and utilize its physics opportunities. In this presentation, I will discuss the plans to upgrade the AGS, the proposed layout of the RHIC siberian snakes, and timetables. The physics focus is the measurement of the spin dependent parton distributions with such accessible probes including high p(t) jets, direct photons, and Drell Yan. The attainable sensitivities and the progress that has been reached in defining the detector requirements will be outlined.

  9. Waves in polar lows

    NASA Astrophysics Data System (ADS)

    Orimolade, A. P.; Furevik, B. R.; Noer, G.; Gudmestad, O. T.; Samelson, R. M.

    2016-08-01

    In a rather stationary fetch, one would not expect large waves in polar low situations. However, the picture changes when one considers a moving fetch. The significant wave heights that may be associated with the recorded polar lows on the Norwegian continental shelf from December 1999 to October 2015 are estimated using a one-dimensional parametric wave model. A comparison of the measured and the forecasted significant wave heights in two recent polar low cases in the Barents Sea is presented. The estimated significant wave heights show that the values could have been up to and above 9 m. The forecasted significant wave heights considerably underestimated the measured significant wave heights in the two recent polar low cases that are considered. Furthermore, a generalization of the fetch-limited wave equation in polar lows is proposed, which allows the wind field to vary in space and time, and is shown to give results that are consistent with the one-dimensional parametric model.

  10. A Compact Polarization Imager

    NASA Technical Reports Server (NTRS)

    Thompson, Karl E.; Rust, David M.; Chen, Hua

    1995-01-01

    A new type of image detector has been designed to analyze the polarization of light simultaneously at all picture elements (pixels) in a scene. The Integrated Dual Imaging Detector (IDID) consists of a polarizing beamsplitter bonded to a custom-designed charge-coupled device with signal-analysis circuitry, all integrated on a silicon chip. The IDID should simplify the design and operation of imaging polarimeters and spectroscopic imagers used, for example, in atmospheric and solar research. Other applications include environmental monitoring and robot vision. Innovations in the IDID include two interleaved 512 x 1024 pixel imaging arrays (one for each polarization plane), large dynamic range (well depth of 10(exp 6) electrons per pixel), simultaneous readout and display of both images at 10(exp 6) pixels per second, and on-chip analog signal processing to produce polarization maps in real time. When used with a lithium niobate Fabry-Perot etalon or other color filter that can encode spectral information as polarization, the IDID can reveal tiny differences between simultaneous images at two wavelengths.

  11. Planar Cell Polarity Signaling: The Developing Cell’s Compass

    PubMed Central

    Vladar, Eszter K.; Antic, Dragana; Axelrod, Jeffrey D.

    2009-01-01

    Cells of many tissues acquire cellular asymmetry to execute their physiologic functions. The planar cell polarity system, first characterized in Drosophila, is important for many of these events. Studies in Drosophila suggest that an upstream system breaks cellular symmetry by converting tissue gradients to subcellular asymmetry, whereas a downstream system amplifies subcellular asymmetry and communicates polarity between cells. In this review, we discuss apparent similarities and differences in the mechanism that controls PCP as it has been adapted to a broad variety of morphological cellular asymmetries in various organisms. PMID:20066108

  12. SCIAMACHY’s View of the Polar Atmosphere

    USGS Publications Warehouse

    Gottwald, M.; Krieg, E.; von Savigny, C.; Noël, S.; Reichl, A.; Bovensmann, H.; Burrows, J.P.

    2007-01-01

    The instrument SCIAMACHY onboard the European ENVISAT mission provides unique capabilities for deriving atmospheric geophysical parameters. Since its launch in early 2002 it has operated successfully in orbit. Due to ENVISAT’s high inclination orbit the polar regions are monitored continuously. We report here results about the status of the polar atmosphere in the past 5 years with special emphasis on the southern hemisphere. This part of the atmosphere is considered to be highly sensitive to anthropogenic impacts on the Earth system and thus to climate change. The acquired data permit retrieving information on the Earth’s atmosphere from troposphere up to the mesosphere

  13. Lucas-Kanade fluid trajectories for time-resolved PIV

    NASA Astrophysics Data System (ADS)

    Yegavian, Robin; Leclaire, Benjamin; Champagnat, Frédéric; Illoul, Cédric; Losfeld, Gilles

    2016-08-01

    We introduce a new method for estimating fluid trajectories in time-resolved PIV. It relies on a Lucas-Kanade paradigm and consists in a simple and direct extension of a two-frame estimation with FOLKI-PIV (Champagnat et al 2011 Exp. Fluids 50 1169-82). The so-called Lucas-Kanade Fluid Trajectories (LKFT) are assumed to be polynomial in time, and are found as the minimizer of a global functional, in which displacements are sought so as to match the intensities of a series of images pairs in the sequence, in the least-squares sense. All pairs involve the central image, similar to other recent time-resolved approaches (FTC (Lynch and Scarano 2013 Meas. Sci. Technol. 24 035305) and FTEE (Jeon et al 2014 Exp. Fluids 55 1-16)). As switching from a two-frame to a time-resolved objective simply amounts to adding terms in a functional, no significant additional algorithmic element is required. Similar to FOLKI-PIV the method is very well suited for GPU acceleration, which is an important feature as computational complexity increases with the image sequence size. Tests on synthetic data exhibiting peak-locking show that increasing the image sequence size strongly reduces both associated bias and random error, and that LKFT has a remaining total error comparable to that of FTEE on this case. Results on case B of the third PIV challenge (Stanislas et al 2008 Exp. Fluids 45 27-71) also show its ability to drastically reduce the error in situations with low signal-to-noise ratio. These results are finally confirmed on experimental images acquired in the near-field of a low Reynolds number jet. Strong reductions in peak-locking, spatial and temporal noise compared to two-frame estimation are also observed, on the displacement components themselves, as well as on spatial or temporal derivatives, such as vorticity and material acceleration.

  14. Time- and Site-Resolved Dynamics in a Topological Circuit

    NASA Astrophysics Data System (ADS)

    Ningyuan, Jia; Owens, Clai; Sommer, Ariel; Schuster, David; Simon, Jonathan

    2015-04-01

    From studies of exotic quantum many-body phenomena to applications in spintronics and quantum information processing, topological materials are poised to revolutionize the condensed-matter frontier and the landscape of modern materials science. Accordingly, there is a broad effort to realize topologically nontrivial electronic and photonic materials for fundamental science as well as practical applications. In this work, we demonstrate the first simultaneous site- and time-resolved measurements of a time-reversal-invariant topological band structure, which we realize in a radio-frequency photonic circuit. We control band-structure topology via local permutation of a traveling-wave capacitor-inductor network, increasing robustness by going beyond the tight-binding limit. We observe a gapped density of states consistent with a modified Hofstadter spectrum at a flux per plaquette of ϕ =π /2 . In situ probes of the band gaps reveal spatially localized bulk states and delocalized edge states. Time-resolved measurements reveal dynamical separation of localized edge excitations into spin-polarized currents. The radio-frequency circuit paradigm is naturally compatible with nonlocal coupling schemes, allowing us to implement a Möbius strip topology inaccessible in conventional systems. This room-temperature experiment illuminates the origins of topology in band structure, and when combined with circuit quantum electrodynamics techniques, it provides a direct path to topologically ordered quantum matter.

  15. Vibrationally resolved cross sections for the photoionization of CS2

    NASA Astrophysics Data System (ADS)

    Stratmann, R. E.; Lucchese, Robert R.

    1994-12-01

    We have performed vibrationally resolved calculations of the excitation of the symmetric stretch in the photoionization of CS2 leading to the X 2Πg, A 2Πu, B 2Σ+u, and C 2Σ+g states of CS+2. Previous theoretical work has determined that the kπg shape resonance in the (5σu)-1 channel consists mainly of a linear combination of low lying virtual d orbitals on sulfur and is thus essentially atomic in nature. This conclusion was primarily based on the shape of the resonant wave function and the insensitivity of the energy of the resonance to bond stretching. Here, we have determined that the energies of the kπ shape resonances located well above threshold and the σ bound states just below threshold are insensitive to bond length. We have also found nearly constant vibrational branching ratios in all channels and polarization components. This is in qualitative agreement with experimental vibrationally resolved cross sections [S. Kakar, H. C. Choi, and E. D. Poliakoff, J. Chem. Phys. 97, 4690 (1992)] which show nearly constant vibrational branching ratios. Our present results indicate that caution must be exercised when using bond length sensitivity as an exclusive means to determine the existence of shape resonances.

  16. DC and subcycle-resolved AC Stark shifts in Helium

    NASA Astrophysics Data System (ADS)

    Liu, Aihua; Thumm, Uwe

    2012-06-01

    We are developing a finite element discrete variable representation (FE-DVR) code to model the response of two-electron atoms to ultra-short pulses of EM radiation. Our first numerical results for the DC stark shift of helium deviate significantly from previous [1] single-active-electron (SAE), but are in close agreement with improved SAE calculations that include the effect of core polarization in the external field. For 3x10^14 W/cm^2 infra red fields, we calculate sub-IR-cycle- resolved instantaneous (AC) level shifts of low-lying bound He states that also strongly deviate from the SAE prediction [1]. We plan to apply our code to model recently measured subcycle time-resolved absorption spectra [2].[4pt] [1] F. He, C. Ruiz, A. Becker, and U. Thumm, J. Phys. B 44, 211001 (2011).[0pt] [2] H. Wang, M. Chini, S. Chen, C.-H. Zhang, F. He, Y. Cheng, Y. Wu, U. Thumm, and Z. Chang, Phys. Rev. Lett. 105, 143002 (2010); M. Chini, Z. Chang et al., to be published.

  17. Acquired and congenital coronary artery abnormalities.

    PubMed

    Young, Ming-Lon; McLeary, Michael; Chan, Kak-Chen

    2017-01-01

    Sudden unexpected cardiac deaths in approximately 20% of young athletes are due to acquired or congenital coronary artery abnormalities. Kawasaki disease is the leading cause for acquired coronary artery abnormalities, which can cause late coronary artery sequelae including aneurysms, stenosis, and thrombosis, leading to myocardial ischaemia and ventricular fibrillation. Patients with anomalous left coronary artery from the pulmonary artery can develop adequate collateral circulation from the right coronary artery in the newborn period, which remains asymptomatic only to manifest in adulthood with myocardial ischaemia, ventricular arrhythmias, and sudden death. Anomalous origin of coronary artery from the opposite sinus occurs in 0.7% of the young general population aged between 11 and 15 years. If the anomalous coronary artery courses between the pulmonary artery and the aorta, sudden cardiac death may occur during or shortly after vigorous exercise, especially in patients where the anomalous left coronary artery originates from the right sinus of Valsalva. Symptomatic patients with evidence of ischaemia should have surgical correction. No treatment is needed for asymptomatic patients with an anomalous right coronary artery from the left sinus of Valsalva. At present, there is no consensus regarding how to manage asymptomatic patients with anomalous left coronary artery from the right sinus of Valsalva and interarterial course. Myocardial bridging is commonly observed in cardiac catheterisation and it rarely causes exercise-induced coronary syndrome or cardiac death. In symptomatic patients, refractory or β-blocker treatment and surgical un-bridging may be considered.

  18. Software for Acquiring Image Data for PIV

    NASA Technical Reports Server (NTRS)

    Wernet, Mark P.; Cheung, H. M.; Kressler, Brian

    2003-01-01

    PIV Acquisition (PIVACQ) is a computer program for acquisition of data for particle-image velocimetry (PIV). In the PIV system for which PIVACQ was developed, small particles entrained in a flow are illuminated with a sheet of light from a pulsed laser. The illuminated region is monitored by a charge-coupled-device camera that operates in conjunction with a data-acquisition system that includes a frame grabber and a counter-timer board, both installed in a single computer. The camera operates in "frame-straddle" mode where a pair of images can be obtained closely spaced in time (on the order of microseconds). The frame grabber acquires image data from the camera and stores the data in the computer memory. The counter/timer board triggers the camera and synchronizes the pulsing of the laser with acquisition of data from the camera. PIVPROC coordinates all of these functions and provides a graphical user interface, through which the user can control the PIV data-acquisition system. PIVACQ enables the user to acquire a sequence of single-exposure images, display the images, process the images, and then save the images to the computer hard drive. PIVACQ works in conjunction with the PIVPROC program which processes the images of particles into the velocity field in the illuminated plane.

  19. [HIV infection and acquired immunodeficiency syndrome].

    PubMed

    Takamatsu, J

    1997-05-01

    On June 4, 1981, MMWR published a report about Pneumocystis carinii pneumonia in homosexual men in Los Angeles. This was the first published report. A years later, this disease was named acquired immunodeficiency syndrome (AIDS). In the following year, Montangier et al in France discovered the causative agent, which they called lymphadenopathy virus (LAV), now known as human immunodeficiency virus (HIV). In 1985, solid-phase enzymeimmunoassay for the detection of the antibody to HIV was developed. Since then, other new techniques for the identification of HIV infection have been become available. These include more sensitive methods (for example; polymerase chain reaction techniques). Although these techniques facilitate early and definite diagnosis of infection, these tests may fail to detect the antibody in sera during window period of infection or overdiagnose infection in sera contaminated with genes not related to HIV. Although preventing blood exposure is the primary means of preventing occupationally acquired human immunodeficiency virus (HIV) infection, appropriate post-exposure management is an important element of workplace safety. Information suggesting that zidovudine (ZDV) postexposure prophylaxis (PEP) may reduce the risk for HIV transmission after occupational exposure to HIV infected blood prompted a Public Health Service (PHS) interagency working group, with expert consultation, and recommendations on PEP and management of occupational exposure to HIV in relation to these findings were discussed.

  20. Treatment of community-acquired pneumonia.

    PubMed

    Lee, Young R; Houngue, Coovi; Hall, Ronald G

    2015-01-01

    Community-acquired pneumonia is the sixth leading cause of death in the USA. Adherence to the 2007 Infectious Diseases Society of America/American Thoracic Society community-acquired pneumonia guidelines has been associated with improved clinical outcomes. However, choice between guideline-recommended treatments is at the discretion of the prescribing clinician. This review is intended to discuss the characteristics of these treatment options including dosing frequency, dose adjustment for renal/hepatic dysfunction, serious/common adverse events, drug interactions, lung penetration, pharmacokinetic-pharmacodynamic target and effect of obesity to help guide antimicrobial selection. An increasing portion of patients are receiving expanded empiric coverage for methicillin-resistant Staphylococcus aureus as recommended by the American Thoracic Society and Infectious Diseases Society of America for healthcare-associated pneumonia. However, this expanded coverage may not be achieving the desired improvements in clinical outcomes. We expect this increasingly diverse spectrum of patients with pneumonia to eventually result in the merger of these two guidelines to include all patients with pneumonia.

  1. Clinicopathological correlation of acquired hyperpigmentary disorders.

    PubMed

    Patel, Anisha B; Kubba, Raj; Kubba, Asha

    2013-01-01

    Acquired pigmentary disorders are group of heterogenous entities that share single, most significant, clinical feature, that is, dyspigmentation. Asians and Indians, in particular, are mostly affected. Although the classic morphologies and common treatment options of these conditions have been reviewed in the global dermatology literature, the value of histpathological evaluation has not been thoroughly explored. The importance of accurate diagnosis is emphasized here as the underlying diseases have varying etiologies that need to be addressed in order to effectively treat the dyspigmentation. In this review, we describe and discuss the utility of histology in the diagnostic work of hyperpigmentary disorders, and how, in many cases, it can lead to targeted and more effective therapy. We focus on the most common acquired pigmentary disorders seen in Indian patients as well as a few uncommon diseases with distinctive histological traits. Facial melanoses, including mimickers of melasma, are thoroughly explored. These diseases include lichen planus pigmentosus, discoid lupus erythematosus, drug-induced melanoses, hyperpigmentation due to exogenous substances, acanthosis nigricans, and macular amyloidosis.

  2. The Acquired Immunodeficiency Syndrome: current status.

    PubMed Central

    Quagliarello, V.

    1982-01-01

    A recently recognized syndrome of acquired immunodeficiency (Acquired Immunodeficiency Syndrome-AIDS) has arisen since June 1981. It has received international attention. The clinical spectrum consists of repeated opportunistic infections, rare malignancies, and autoimmune phenomena, occurring in previously healthy adults with no history of an immunologic disorder. The population subset at risk for this syndrome appears to be predominantly homosexual American males and intravenous drug abusers with rare cases being reported in heterosexuals, hemophiliacs, and foreign patients, especially Haitians. The immunologic aberrancy in all patients described appears limited to T-lymphocyte hyporesponsiveness and imbalance of T-helper and suppressor cells. This disordered immunoregulation is a consistent finding in all reported cases and appears to predispose to the opportunistic infections and malignancies which have been associated with a 40 percent mortality. The underlying factor responsible for the immunoregulatory defect is unknown but possible etiologies include a transmissible infectious agent, drug use, chronic antigen stimulation, and spermatozoa exposure. Treatment of the associated infections and malignancies has been a frustrating endeavor as many patients respond incompletely or relapse soon after successful treatment course. Preventive measures, including patient education, physician awareness, and immunomodulating agents, are discussed. PMID:6134399

  3. Polarization imaging detection technology research

    NASA Astrophysics Data System (ADS)

    Xue, Mo-gen; Wang, Feng; Xu, Guo-ming; Yuan, Hong-wu

    2013-09-01

    In this paper we analyse the polarization imaging theory and the commonly process of the polarization imaging detection. Based on this, we summarize our many years' research work especially in the mechanism, technology and system of the polarization imaging detection technology. Combined with the up-to-date development at home and abroad, this paper discusses many theory and technological problems of polarization imaging detection in detail from the view of the object polarization characteristics, key problem and key technology of polarization imaging detection, polarization imaging detection system and application, etc. The theory and technological problems include object all direction polarization characteristic retrieving, the optical electronic machinery integration designing of the polarization imaging detection system, the high precision polarization information analysis and the polarization image fast processing. Moreover, we point out the possible application direction of the polarization imaging detection technology both in martial and civilian fields. We also summarize the possible future development trend of the polarization imaging detection technology in the field of high spectrum polarization imaging. This paper can provide evident reference and guidance to promote the research and development of the polarization imaging detection technology.

  4. Depolarization in polarizing supermirrors

    NASA Astrophysics Data System (ADS)

    Klauser, Christine; Bigault, Thierry; Böni, Peter; Courtois, Pierre; Devishvili, Anton; Rebrova, Nataliya; Schneider, Michael; Soldner, Torsten

    2016-12-01

    We present data on depolarizing effects in polarizing mirrors. At typical magnetizing field strengths used in polarizing devices, depolarizations rise up to the percent level in the specular region and are shown to be successfully suppressed to 10-4 when increasing the magnetizing field. We show evidence linking a part of this depolarization to lateral correlation of the magnetization fluctuations in the ferromagnetic layers. Effects of the supermirror factor (m), wavelength and incidence angle are studied. The findings are applied to a crossed supermirror geometry and we report a neutron beam polarization of 99.97(1)% for a beam of wavelength λ = 5.3 Å, Δλ/λ = 0.1 (FWHM).

  5. North Polar Layers

    NASA Technical Reports Server (NTRS)

    2004-01-01

    3 December 2004 This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows an exposure of finely-detailed layers in the martian north polar region. The polar ice cap, which is made up of frozen water (whereas the south polar cap is mostly frozen carbon dioxide), is underlain by a thick sequence of layers. Some have speculated that these layers may record the history of changes in martian climate during the past few hundreds of millions of years. This picture is located near 86.0oN, 30.2oW, and covers an area approximately 3 km (1.9 mi) across. Sunlight illuminates the scene from the lower left.

  6. A lunar polar expedition

    NASA Technical Reports Server (NTRS)

    Dowling, Richard; Staehle, Robert L.; Svitek, Tomas

    1992-01-01

    Advanced exploration and development in harsh environments require mastery of basic human survival skill. Expeditions into the lethal climates of Earth's polar regions offer useful lessons for tommorrow's lunar pioneers. In Arctic and Antarctic exploration, 'wintering over' was a crucial milestone. The ability to establish a supply base and survive months of polar cold and darkness made extensive travel and exploration possible. Because of the possibility of near-constant solar illumination, the lunar polar regions, unlike Earth's may offer the most hospitable site for habitation. The World Space Foundation is examining a scenario for establishing a five-person expeditionary team on the lunar north pole for one year. This paper is a status report on a point design addressing site selection, transportation, power, and life support requirements.

  7. [Polar body diagnosis].

    PubMed

    Montag, M; van der Ven, K; van der Ven, H

    2009-01-01

    Polar body diagnosis (PBD) is a diagnostic method for the indirect genetic analysis of oocytes. Polar bodies are by-products of the meiotic cell cycle which have no influence on further embryo development. The biopsy of polar bodies can be accomplished either by zona drilling or laser drilling within a very short time period. The paternal contribution to the genetic constitution of the developing embryo cannot be diagnosed by PBD. The major application of PBD is the detection of maternally derived chromosomal aneuploidies and translocations in oocytes. For these indications, PBD may offer a viable alternative to blastomere biopsy as the embryo's integrity remains unaffected in contrast to preimplantation genetic diagnosis by blastomere biopsy. The fast development in the field of molecular diagnostics will also influence PBD and probably allow a more general diagnosis in the future.

  8. South Polar Layers

    NASA Technical Reports Server (NTRS)

    2003-01-01

    MGS MOC Release No. MOC2-516, 17 October 2003

    This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows eroded, stair-stepped layers in the south polar region of Mars. These layers have been considered, for the past three decades, to consist of a mixture of dust and ice. The Mars Polar Lander (MPL) mission was designed to test this hypothesis. However, sadly, MPL was lost during descent in December 1999. This exposure of south polar layered material is located near 86.3oS, 187.7oW. The image covers an area 3 km (1.9 mi) wide and is illuminated by sunlight from the upper left.

  9. Spring polar ozone behavior

    NASA Technical Reports Server (NTRS)

    Aikin, Arthur C.

    1992-01-01

    Understanding of the springtime behavior of polar stratospheric ozone as of mid 1990 is summarized. Heterogeneous reactions on polar stratospheric clouds as hypothesis for ozone loss are considered and a simplified description of the behavior of Antarctic ozone in winter and spring is given. Evidence that the situation is more complicated than described by the theory is produced. Many unresolved scientific issues remain and some of the most important problems are identified. Ozone changes each spring since 1979 have clearly established for the first time that man made chlorine compounds influence stratospheric ozone. Long before important advances in satellite and in situ investigations, it was Dobson's decision to place a total ozone measuring spectrometer at Halley Bay in Antarctica during the International Geophysical Year and subsequent continuous monitoring which led to the discovery that ozone was being destroyed each spring by chlorine processed by polar stratospheric clouds.

  10. North Polar Cap

    NASA Technical Reports Server (NTRS)

    2004-01-01

    7 September 2004 This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows a 1.4 m/pixel (5 ft/pixel) view of a typical martian north polar ice cap texture. The surface is pitted and rough at the scale of several meters. The north polar residual cap of Mars consists mainly of water ice, while the south polar residual cap is mostly carbon dioxide. This picture is located near 85.2oN, 283.2oW. The image covers an area approximately 1 km wide by 1.4 km high (0.62 by 0.87 miles). Sunlight illuminates this scene from the lower left.

  11. Polarization of deuterium molecules

    SciTech Connect

    J. F. J. van den Brand; H. J. Bulten; M. Ferro-Luzzi; Z.-L. Zhou; Ricardo Alarcon; T. Botto; M. Bouwhuis; Rolf Ent; Peter Heimberg; Douglas W. Higinbotham; Kees de Jager; J. Lang; D. J. de Lange; I. Passchier; H. R. Poolman; J. J. M. Steijger; O. Unal; H. de Vries

    1997-08-01

    For molecular systems, spin relaxation is expected to be suppressed compared to the case of atoms, since the paired electrons in a hydrogen or deuterium molecule are chemically stable, and only weakly interact with the spin of the nucleus. Such systems would be largely insensitive to polarization losses due to spin-exchange collisions, to the interaction of the electron spins with external fields (e.g. the RF-field of a bunched charged-particle beam), and/or to the presence of container walls. Here, we discuss the results of a recent experiment where we obtained evidence that nuclear polarization is maintained, when polarized atoms recombine to molecules on a copper surface (in a magnetic field of 23 mT and at a density of about 10{sup 12} molecules {center_dot} cm{sup -3}).

  12. POLARIZED NEUTRONS IN RHIC

    SciTech Connect

    COURANT,E.D.

    1998-04-27

    There does not appear to be any obvious way to accelerate neutrons, polarized or otherwise, to high energies by themselves. To investigate the behavior of polarized neutrons the authors therefore have to obtain them by accelerating them as components of heavier nuclei, and then sorting out the contribution of the neutrons in the analysis of the reactions produced by the heavy ion beams. The best neutron carriers for this purpose are probably {sup 3}He nuclei and deuterons. A polarized deuteron is primarily a combination of a proton and a neutron with their spins pointing in the same direction; in the {sup 3}He nucleus the spins of the two protons are opposite and the net spin (and magnetic moment) is almost the same as that of a free neutron. Polarized ions other than protons may be accelerated, stored and collided in a ring such as RHIC provided the techniques proposed for polarized proton operation can be adapted (or replaced by other strategies) for these ions. To accelerate polarized particles in a ring, one must make provisions for overcoming the depolarizing resonances that occur at certain energies. These resonances arise when the spin tune (ratio of spin precession frequency to orbit frequency) resonates with a component present in the horizontal field. The horizontal field oscillates with the vertical motion of the particles (due to vertical focusing); its frequency spectrum is dominated by the vertical oscillation frequency and its modulation by the periodic structure of the accelerator ring. In addition, the magnet imperfections that distort the closed orbit vertically contain all integral Fourier harmonics of the orbit frequency.

  13. Spectrally Resolved Magnetic Resonance Imaging of the XenonBiosensor

    SciTech Connect

    Hilty, Christian; Lowery, Thomas; Wemmer, David; Pines, Alexander

    2005-07-15

    Due to its ability to non-invasively record images, as well as elucidate molecular structure, nuclear magnetic resonance is the method of choice for applications as widespread as chemical analysis and medical diagnostics. Its detection threshold is, however, limited by the small polarization of nuclear spins in even the highest available magnetic fields. This limitation can, under certain circumstances, be alleviated by using hyper-polarized substances. Xenon biosensors make use of the sensitivity gain of hyperpolarized xenon to provide magnetic resonance detection capability for a specific low-concentration target. They consist of a cryptophane cage, which binds one xenon atom, and which has been connected via a linker to a targeting moiety such as a ligand or antibody. Recent work has shown the possibility of using the xenon biosensor to detect small amounts of a substance in a heterogeneous environment by NMR. Here, we demonstrate that magnetic resonance (MR) provides the capability to obtain spectrally and spatially resolved images of the distribution of immobilized biosensor, opening the possibility for using the xenon biosensor for targeted imaging.

  14. Polar Marine Microorganisms and Climate Change.

    PubMed

    Verde, C; Giordano, D; Bellas, C M; di Prisco, G; Anesio, A M

    2016-01-01

    The large diversity of marine microorganisms harboured by oceans plays an important role in planet sustainability by driving globally important biogeochemical cycles; all primary and most secondary production in the oceans is performed by microorganisms. The largest part of the planet is covered by cold environments; consequently, cold-adapted microorganisms have crucial functional roles in globally important environmental processes and biogeochemical cycles cold-adapted extremophiles are a remarkable model to shed light on the molecular basis of survival at low temperature. The indigenous populations of Antarctic and Arctic microorganisms are endowed with genetic and physiological traits that allow them to live and effectively compete at the temperatures prevailing in polar regions. Some genes, e.g. glycosyltransferases and glycosylsynthetases involved in the architecture of the cell wall, may have been acquired/retained during evolution of polar strains or lost in tropical strains. This present work focusses on temperature and its role in shaping microbial adaptations; however, in assessing the impacts of climate changes on microbial diversity and biogeochemical cycles in polar oceans, it should not be forgotten that physiological studies need to include the interaction of temperature with other abiotic and biotic factors.

  15. North Polar Scarp

    NASA Technical Reports Server (NTRS)

    2004-01-01

    3 March 2004 The north polar cap of Mars overlies a series of layered materials. The upper-most layers are light-toned and may include ice and perhaps dust. The lower layers may be less icy and contain some amount of dark sand. This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows an exposure of north polar layers located near 83.9oN, 237.9oW. This view covers an area 3 km (1.9 mi) wide and is illuminated by sunlight from the lower left.

  16. Polar Ozone Losses

    NASA Technical Reports Server (NTRS)

    Newman, Paul A.; Bhartia, P. K. (Technical Monitor)

    2001-01-01

    Since the discovery of the Antarctic ozone hole, a great deal of attention has been focused on the polar regions to both identify the chemistry and physics of the large losses, and to provide an understanding of the future of polar ozone. In this review talk, I will discuss the secular trends of ozone in both the Antarctic and Arctic regions, and I will review some of the principal research results of the last few years. In particular, I will emphasize some of the results from the SOLVE-THESEO 2000 campaign that occurred over the course of the winter of 1999-2000.

  17. New compact neutron polarizer

    NASA Astrophysics Data System (ADS)

    Krist, Th; Kennedy, S. J.; Hicks, T. J.; Mezei, F.

    A new type of a neutron polarizing bender was developed in co-operation with BENSC and ANSTO. It is based upon bent thin silicon wafers coated on one side with SiFeCo polarizing supermirrors and on the other side with Gd. Initial tests at BENSC in a 300 Oe magnetic field yielded a transmission of spin-up neutrons of about 55% over an angle range of 0.75° and flipping ratios > 30. Subsequent tests at ANSTO at 1200 Oe yielded a transmission of 48% with a flipping ratio > 45.

  18. Internal polarized targets

    SciTech Connect

    Kinney, E.R.; Coulter, K.; Gilman, R.; Holt, R.J.; Kowalczyk, R.S.; Napolitano, J.; Potterveld, D.H.; Young, L. ); Mishnev, S.I.; Nikolenko, D.M.; Popov, S.G.; Rachek, I.A.; Temnykh, A.B.; Toporkov, D.K.; Tsentalovich, E.P.; Wojtsekhowski, B.B. . Inst. Yadernoj Fiziki)

    1989-01-01

    Internal polarized targets offer a number of advantages over external targets. After a brief review of the basic motivation and principles behind internal polarized targets, the technical aspects of the atomic storage cell will be discussed in particular. Sources of depolarization and the means by which their effects can be ameliorated will be described, especially depolarization by the intense magnetic fields arising from the circulating particle beam. The experience of the Argonne Novosibirsk collaboration with the use of a storage cell in a 2 GeV electron storage ring will be the focus of this technical discussion. 17 refs., 11 figs.

  19. Microwave Frequency Polarizers

    NASA Technical Reports Server (NTRS)

    Ha, Vien The; Mirel, Paul; Kogut, Alan J.

    2013-01-01

    This article describes the fabrication and analysis of microwave frequency polarizing grids. The grids are designed to measure polarization from the cosmic microwave background. It is effective in the range of 500 to 1500 micron wavelength. It is cryogenic compatible and highly robust to high load impacts. Each grid is fabricated using an array of different assembly processes which vary in the types of tension mechanisms to the shape and size of the grids. We provide a comprehensive study on the analysis of the grids' wire heights, diameters, and spacing.

  20. South Polar Cap

    NASA Technical Reports Server (NTRS)

    2005-01-01

    8 December 2005 This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows landforms created by sublimation processes on the south polar residual cap of Mars. The bulk of the ice in the south polar residual cap is frozen carbon dioxide.

    Location near: 86.6oS, 342.2oW Image width: width: 3 km (1.9 mi) Illumination from: upper left Season: Southern Summer

  1. Polarized emission in polariton condensates: Switching in a one-dimensional natural trap versus inversion in two dimensions

    NASA Astrophysics Data System (ADS)

    Cuadra, J.; Sarkar, D.; Viña, L.; Hvam, J. M.; Nalitov, A.; Solnyshkov, D.; Malpuech, G.

    2013-12-01

    We perform polarization resolved spectroscopy of two- and one-dimensional microcavity-polariton condensates, which are formed by exciting the system in the optical parametric oscillator configuration. We observe polarization inversion for linearly polarized pumping parallel to the wire in both the 1D and 2D systems. As the polarization plane of the pump is rotated, the degree of linear polarization of the 2D system oscillates between orthogonal polarizations with the same period as that of the pump. However, the 1D system switches abruptly between two states of high degree of linear polarization with half the period. Two complementary models, based on semiclassical Boltzmann kinetic equations and the Gross-Pitaevskii equation, respectively, obtain an excellent agreement with the experimental results, providing a deep insight into the mechanisms responsible for the polarization switching.

  2. Sensitivity of envelope following responses to vowel polarity.

    PubMed

    Easwar, Vijayalakshmi; Beamish, Laura; Aiken, Steven; Choi, Jong Min; Scollie, Susan; Purcell, David

    2015-02-01

    Envelope following responses (EFRs) elicited by stimuli of opposite polarities are often averaged due to their insensitivity to polarity when elicited by amplitude modulated tones. A recent report illustrates that individuals exhibit varying degrees of polarity-sensitive differences in EFR amplitude when elicited by vowel stimuli (Aiken and Purcell, 2013). The aims of the current study were to evaluate the incidence and degree of polarity-sensitive differences in EFRs recorded in a large group of individuals, and to examine potential factors influencing the polarity-sensitive nature of EFRs. In Experiment I of the present study, we evaluated the incidence and degree of polarity-sensitive differences in EFR amplitude in a group of 39 participants. EFRs were elicited by opposite polarities of the vowel /ε/ in a natural /hVd/ context presented at 80 dB SPL. Nearly 30% of the participants with detectable responses (n = 24) showed a difference of greater than ∼39 nV in EFR response amplitude between the two polarities, that was unexplained by variations in noise estimates. In Experiment II, we evaluated the effect of vowel, frequency of harmonics and presence of the first harmonic (h1) on the polarity sensitivity of EFRs in 20 participants with normal hearing. For vowels /u/, /a/ and /i/, EFRs were elicited by two simultaneously presented carriers representing the first formant (resolved harmonics), and the second and higher formants (unresolved harmonics). Individual but simultaneous EFRs were elicited by the formant carriers by separating the fundamental frequency in the two carriers by 8 Hz. Vowels were presented as part of a naturally produced, but modified sequence /susaʃi/, at an overall level of 65 dB SPL. To evaluate the effect of h1 on polarity sensitivity of EFRs, EFRs were elicited by the same vowels without h1 in an identical sequence. A repeated measures analysis of variance indicated a significant effect of polarity on EFR amplitudes for the

  3. [Clinical cases of acquired coagulation inhibitors].

    PubMed

    Yamane, T; Hino, M; Ota, K; Akahori, M; Hirai, M; Inoue, T; Mugitani, A; Tatsumi, N

    2000-12-01

    The acquired coagulation factor inhibitors are classified into alloantibodies, which appear in association with supplementary treatment for congenital coagulation factor deficiency, and autoantibodies, which are spontaneously produced. We report here 2 cases of acquired factor VIII inhibitor and 1 case of factor V inhibitor. Case 1: A 52-year-old woman noted swelling of the right parotid region in March 1988. Though contrast examination was scheduled, she was admitted for detailed examination due to a markedly prolonged coagulation time. An APTT correction test suggested that decreased factor VIII activity was due to the presence of an inhibitor. Since antinuclear antibody and SS-A antibody were positive and infiltration by lymphocytes in the salivary gland acini in a lip biopsy specimen was detected, Sjögren's syndrome was diagnosed. Case 2: A 33-year-old woman had normal delivery of her second child in February 1998. In June 1998, she suffered slight contusion in the left lower limb. The affected site became swollen and painful, making walking difficult. Since both upper limbs became markedly swollen after 1 week, she visited our hospital. Prolonged APTT and a marked decrease in factor VIII activity were observed. Factor VIII inhibitor titer was high at 19 Bethesda units. Case 3: A 64-year-old man had had asymptomatic macroscopic hematuria since the beginning of August 1998 but was placed under observation since no abnormal findings were observed on various imaging tests. However, he was admitted to Osaka City General Medical Center because of vesicular tamponade. Factor V activity was markedly decreased to 1.0%. PT correction test suggested that decreased factor V activity was due to the presence of an inhibitor. The underlying disease could not be determined in this case. In patients with acquired coagulation inhibitors, bleeding symptoms are reported to be mild in many cases, and severe bleeding is rare. However, cases of death without severe bleeding or

  4. Phase-Controlled Polarization Modulators

    NASA Technical Reports Server (NTRS)

    Chuss, D. T.; Wollack, E. J.; Novak, G.; Moseley, S. H.; Pisano, G.; Krejny, M.; U-Yen, K.

    2012-01-01

    We report technology development of millimeter/submillimeter polarization modulators that operate by introducing a a variable, controlled phase delay between two orthogonal polarization states. The variable-delay polarization modulator (VPM) operates via the introduction of a variable phase delay between two linear orthogonal polarization states, resulting in a variable mapping of a single linear polarization into a combination of that Stokes parameter and circular (Stokes V) polarization. Characterization of a prototype VPM is presented at 350 and 3000 microns. We also describe a modulator in which a variable phase delay is introduced between right- and left- circular polarization states. In this architecture, linear polarization is fully modulated. Each of these devices consists of a polarization diplexer parallel to and in front of a movable mirror. Modulation involves sub-wavelength translations of the mirror that change the magnitude of the phase delay.

  5. Chasma Boreale in the North Polar Region

    NASA Technical Reports Server (NTRS)

    2006-01-01

    This images shows a Compact Reconnaissance Imaging Spectrometer for Mars (CRISM) full-resolution 'targeted image' of the edge of Mars' north polar cap. The region in the image, Chasma Boreale, is a valley several kilometers or miles deep that cuts about 400 kilometers (about 250 miles) into the edge of the cap.

    This image was acquired at 0851 UTC (4:51 a.m. EDT) on Oct. 1, 2006, near 84.6 degrees north latitude, 3.6 degrees east longitude. It covers an area about 13 kilometers (8 miles) long and, at the narrowest point, about 9 kilometers (5.6 miles) wide. At the center of the image the spatial resolution is as good as 18 meters (60 feet) per pixel. The image was taken in 544 colors covering wavelengths of 0.36 to 3.92 micrometers. Two renderings of the data are shown here, both draped over topography without vertical exaggeration, and then viewed from a perspective diagonally above the site. The top view is an approximately true-color representation. The bottom view, constructed from infrared wavelengths, shows strength of the spectral signature of ice. Brighter areas are rich in ice, and dark areas have little ice.

    The polar cap has long been recognized to contain layers composed of dust and ice, and hence has been named the polar layered deposit. This sits atop an underlying 'basal unit.' The upper part of the basal unit is dark at visible wavelengths and steeply sloped, whereas the lower part of the basal unit is brighter, redder, and layered like the polar layered deposits. The chasma floor is cratered, and in the foreground it is covered by dunes that are outliers of a north polar sand sea that surrounds the polar cap. The polar layered deposits and the basal unit form a steeply sloping scarp about 1.1 kilometers (0.7 miles) high.

    CRISM's image of this region shows a number of previously unrecognized characteristics of the polar layered deposits and the basal unit. First, the ice-rich polar layered deposits exhibit coherent banding both at

  6. Long-Lived Valley Polarization of Intravalley Trions in Monolayer WSe2

    NASA Astrophysics Data System (ADS)

    Singh, Akshay; Tran, Kha; Kolarczik, Mirco; Seifert, Joe; Wang, Yiping; Hao, Kai; Pleskot, Dennis; Gabor, Nathaniel M.; Helmrich, Sophia; Owschimikow, Nina; Woggon, Ulrike; Li, Xiaoqin

    2016-12-01

    We investigate valley dynamics associated with trions in monolayer tungsten diselenide (WSe2 ) using polarization resolved two-color pump-probe spectroscopy. When tuning the pump and probe energy across the trion resonance, distinct trion valley polarization dynamics are observed as a function of energy and attributed to the intravalley and intervalley trions in monolayer WSe2 . We observe no decay of a near-unity valley polarization associated with the intravalley trions during ˜ 25 ps , while the valley polarization of the intervalley trions exhibits a fast decay of ˜4 ps . Furthermore, we show that resonant excitation is a prerequisite for observing the long-lived valley polarization associated with the intravalley trion. The exceptionally robust valley polarization associated with resonantly created intravalley trions discovered here may be explored for future valleytronic applications such as valley Hall effects.

  7. Visualization and manipulation of meta-stable polarization variants in multiferroic materials

    NASA Astrophysics Data System (ADS)

    Park, Moonkyu; No, Kwangsoo; Hong, Seungbum

    2013-04-01

    Here we demonstrate the role of meta-stable polarization variants in out-of-plane polarization switching behavior in epitaxially grown BiFeO3 thin films using angle-resolved piezoresponse force microscopy (AR-PFM). The out-of-plane polarization switching mainly occurred at the boundary between meta-stable and stable polarization domains, and was accompanied by a significant change in in-plane domain configuration from complicated structure with 12 polarization variants to simple stripe structure with 4 polarization variants. These results imply that the biased tip rearranges the delicately balanced domain configuration, which is determined by the competition between electrostatic and strain energies, into simple interweaving one that is more thermodynamically stable.

  8. Revealing Fundamental Interactions: the Role of Polarized Positrons and Electrons at the Linear Collider

    SciTech Connect

    Moortgat-Pick, G.; Abe, T.; Alexander, G.; Ananthanarayan, B.; Babich, A.A.; Bharadwaj, V.; Barber, D.; Bartl, A.; Brachmann, A.; Chen, S.; Clarke, J.; Clendenin, J.E.; Dainton, J.; Desch, K.; Diehl, M.; Dobos, B.; Dorland, T.; Eberl, H.; Ellis, John R.; Flottman, K.; Frass, H.; /CERN /Durham U., IPPP /Colorado U. /Tel-Aviv U. /Bangalore, Indian Inst. Sci. /Gomel State Tech. U. /SLAC /DESY /Vienna U. /Daresbury /Liverpool U. /Freiburg U. /Vienna, OAW /Wurzburg U. /Fermilab /Uppsala U. /Waseda U., RISE /Warsaw U. /Bonn U. /Aachen, Tech. Hochsch. /Cornell U., Phys. Dept.

    2005-07-06

    The proposed International Linear Collider (ILC) is well-suited for discovering physics beyond the Standard Model and for precisely unraveling the structure of the underlying physics. The physics return can be maximized by the use of polarized beams. This report shows the paramount role of polarized beams and summarizes the benefits obtained from polarizing the positron beam, as well as the electron beam. The physics case for this option is illustrated explicitly by analyzing reference reactions in different physics scenarios. The results show that positron polarization, combined with the clean experimental environment provided by the linear collider, allows to improve strongly the potential of searches for new particles and the identification of their dynamics, which opens the road to resolve shortcomings of the Standard Model. The report also presents an overview of possible designs for polarizing both beams at the ILC, as well as for measuring their polarization.

  9. The Role of polarized positrons and electrons in revealing fundamental interactions at the linear collider

    SciTech Connect

    Moortgat-Pick, G.; Abe, T.; Alexander, G.; Ananthanarayan, B.; Babich, A.A.; Bharadwaj, V.; Barber, D.; Bartl, A.; Brachmann, A.; Chen, S.; Clarke, J.; Clendenin, J.E.; Dainton, J.; Desch, K.; Diehl, M.; Dobos, B.; Dorland, T.; Eberl, H.; Ellis, John R.; Flottman, K.; Frass, H.; /CERN /Durham U., IPPP /Colorado U. /Tel-Aviv U. /Bangalore, Indian Inst. Sci. /Gomel State Tech. U. /SLAC /DESY /Vienna U. /Daresbury /Liverpool U. /Freiburg U. /Vienna, OAW /Wurzburg U. /Fermilab /Uppsala U. /Waseda U., RISE /Warsaw U. /Bonn U. /Aachen, Tech. Hochsch. /Cornell U., Phys. Dept.

    2005-07-01

    The proposed International Linear Collider (ILC) is well-suited for discovering physics beyond the Standard Model and for precisely unraveling the structure of the underlying physics. The physics return can be maximized by the use of polarized beams. This report shows the paramount role of polarized beams and summarizes the benefits obtained from polarizing the positron beam, as well as the electron beam. The physics case for this option is illustrated explicitly by analyzing reference reactions in different physics scenarios. The results show that positron polarization, combined with the clean experimental environment provided by the linear collider, allows to improve strongly the potential of searches for new particles and the identification of their dynamics, which opens the road to resolve shortcomings of the Standard Model. The report also presents an overview of possible designs for polarizing both beams at the ILC, as well as for measuring their polarization.

  10. ACECARD. Acquire CoOmmodities Easily Card

    SciTech Connect

    Soler, E.E.

    1996-09-01

    Acquire Commodities Easily Card (AceCard) provides an automated end-user method to distribute company credit card charges to internal charge numbers. AceCard will allow cardholders to record card purchases in an on-line order log, enter multiple account distributions per order that can be posted to the General Ledger, track orders, and receipt information, and provide a variety of cardholder and administrative reports. Please note: Customers must contact Ed Soler (423)-576-6151, Lockheed Martin Energy Systems, for help with the installation of the package. The fee for this installation help will be coordinated by the customer and Lockheed Martin and is in addition to cost of the package from ESTSC. Customers should contact Sandy Presley (423)-576-4708 for user help.

  11. Acquire CoOmmodities Easily Card

    SciTech Connect

    Soler, E. E.

    1998-05-29

    Acquire Commodities Easily Card (AceCard) provides an automated end-user method to distribute company credit card charges to internal charge numbers. AceCard will allow cardholders to record card purchases in an on-line order log, enter multiple account distributions per order that can be posted to the General Ledger, track orders, and receipt information, and provide a variety of cardholder and administrative reports. Please note: Customers must contact Ed Soler (423)-576-6151, Lockheed Martin Energy Systems, for help with the installation of the package. The fee for this installation help will be coordinated by the customer and Lockheed Martin and is in addition to cost of the package from ESTSC. Customers should contact Sandy Presley (423)-576-4708 for user help.

  12. Stereotypic movement disorder after acquired brain injury.

    PubMed

    McGrath, Cynthia M; Kennedy, Richard E; Hoye, Wayne; Yablon, Stuart A

    2002-05-01

    Stereotypic movement disorder (SMD) consists of repetitive, non-functional motor behaviour that interferes with daily living or causes injury to the person. It is most often described in patients with mental retardation. However, recent evidence indicates that this condition is common among otherwise normal individuals. This case study describes a patient with new-onset SMD occurring after subdural haematoma and brain injury. SMD has rarely been reported after acquired brain injury, and none have documented successful treatment. The current psychiatric literature regarding neurochemistry, neuroanatomy, and treatment of SMD are reviewed with particular application to one patient. Treatment options include serotonin re-uptake inhibitors, opioid antagonists and dopamine antagonists. SMD has been under-appreciated in intellectually normal individuals, and may also be unrecognized after brain injury. Further investigation is needed in this area, which may benefit other individuals with SMD as well.

  13. Innate and acquired bacteriophage-mediated immunity

    PubMed Central

    Barr, Jeremy J.; Youle, Merry; Rohwer, Forest

    2013-01-01

    We recently described a novel, non-host-derived, phage-mediated immunity active at mucosal surfaces, the main site of pathogen entry in metazoans. In that work, we showed that phage T4 adheres to mucus glycoproteins via immunoglobulin-like domains displayed on its capsid. This adherence positions the phage in mucus surfaces where they are more likely to encounter and kill bacteria, thereby benefiting both the phage and its metazoan host. We presented this phage-metazoan symbiosis based on an exclusively lytic model of phage infection. Here we extend our bacteriophage adherence to mucus (BAM) model to consider the undoubtedly more complex dynamics in vivo. We hypothesize how mucus-adherent phages, both lytic and temperate, might impact the commensal microbiota as well as protect the metazoan epithelium from bacterial invasion. We suggest that BAM may provide both an innate and an acquired antimicrobial immunity. PMID:24228227

  14. Acquired immunodeficiency syndrome and health care professionals.

    PubMed

    Menon, V; Bharucha, K

    1994-01-01

    As health care professionals, we face a grave risk of acquiring HIV infection in the course of our work. But how many of us really know the precautions to be applied in the hospital set up in dealing with HIV infected patients? A knowledge, attitude and practice (KAP) study was conducted in Pune hospitals to assess the current status. Among the results 65% servants had not heard of AIDS, 85% nursing staff did not apply the Universal Safety Precautions (USP) approach, 13.5% resident thought that the HIV was not transmitted by blood, 30% consultants would avoid contact with an HIV positive patient. This study has shown that definite lacunae exist in knowledge specific to the particular population in question. A proposal for an education programme which is target specific and one of constant renewal is sought.

  15. Signal regulators of systemic acquired resistance

    PubMed Central

    Gao, Qing-Ming; Zhu, Shifeng; Kachroo, Pradeep; Kachroo, Aardra

    2015-01-01

    Salicylic acid (SA) is an important phytohormone that plays a vital role in a number of physiological responses, including plant defense. The last two decades have witnessed a number of breakthroughs related to biosynthesis, transport, perception and signaling mediated by SA. These findings demonstrate that SA plays a crictical role in both local and systemic defense responses. Systemic acquired resistance (SAR) is one such SA-dependent response. SAR is a long distance signaling mechanism that provides broad spectrum and long-lasting resistance to secondary infections throughout the plant. This unique feature makes SAR a highly desirable trait in crop production. This review summarizes the recent advances in the role of SA in SAR and discusses its relationship to other SAR inducers. PMID:25918514

  16. Acquired Localized Hypertrichosis Induced by Rivastigmine

    PubMed Central

    Imbernón-Moya, Adrian; Podlipnik, Sebastian; Burgos, Fernando; Vargas-Laguna, Elena; Aguilar-Martínez, Antonio; Fernández-Cogolludo, Eva; Gallego-Valdes, Miguel Angel

    2016-01-01

    Hypertrichosis is the excessive hair growth in any area of the skin surface. Acquired localized hypertrichosis may be secondary to multiple causes and there is a secondary form due to several drugs, which is usually reversible with discontinuation of the causative agent. Rivastigmine is a reversible and competitive inhibitor of acetylcholinesterase and butyrylcholinesterase used for symptomatic treatment of Alzheimer dementia and Parkinson's disease. It has an adequate safety profile and cutaneous side effects are unusual. Irritant contact dermatitis, allergic dermatitis, baboon syndrome, and cutaneous rash due to rivastigmine have been reported. We report on a Caucasian 80-year-old male with personal history of Alzheimer's disease. The patient started therapy with oral rivastigmine one month prior to clinical presentation of localized hypertrichosis on both forearms. Norgalanthamine has been shown to promote hair growth activity via the proliferation of dermal papilla. Acetylcholinesterase inhibitors can induce hair growth. PMID:27073702

  17. Treatment of the acquired von Willebrand syndrome.

    PubMed

    Budde, Ulrich; Scheppenheim, Sonja; Dittmer, Rita

    2015-12-01

    Acquired von Willebrand syndrome (aVWS) accounts for 22% of patients with abnormal von Willebrand factor. Most patients with known pathophysiological mechanisms suffer from cardiovascular, myeloproliferative and lymphoproliferative disorders. Less frequent associations are of autoimmune origin, due to hyperfibrinolysis, adsorption to tumor cells, reduced synthesis and prolonged circulation. The mechanisms leading to aVWS is hitherto not known in patients with liver and kidney diseases, drug use, glycogen storage disease, virus infections and at least 18 other disease entities. Diagnosis is complicated by the battery of tests needed, and their inherent rather low sensitivity and specificity for aVWS. Thus, even in acute bleeding situations it may take days until a firm diagnosis is settled and specific therapies can be initiated. The main aim is to shed more light onto this, compared with inherited von Willebrand disease, rare disease which affects at least 2-3% of the older population.

  18. Intensive care unit-acquired weakness.

    PubMed

    Horn, J; Hermans, G

    2017-01-01

    When critically ill, a severe weakness of the limbs and respiratory muscles often develops with a prolonged stay in the intensive care unit (ICU), a condition vaguely termed intensive care unit-acquired weakness (ICUAW). Many of these patients have serious nerve and muscle injury. This syndrome is most often seen in surviving critically ill patients with sepsis or extensive inflammatory response which results in increased duration of mechanical ventilation and hospital length of stay. Patients with ICUAW often do not fully recover and the disability will seriously impact on their quality of life. In this chapter we discuss the current knowledge on the pathophysiology and risk factors of ICUAW. Tools to diagnose ICUAW, how to separate ICUAW from other disorders, and which possible treatment strategies can be employed are also described. ICUAW is finally receiving the attention it deserves and the expectation is that it can be better understood and prevented.

  19. Severe acquired anaemia in Africa: new concepts.

    PubMed

    van Hensbroek, Michael B; Jonker, Femkje; Bates, Imelda

    2011-09-01

    Severe anaemia is common in Africa. It has a high mortality and particularly affects young children and pregnant women. Recent research provides new insights into the mechanisms and causes of severe acquired anaemia and overturns accepted dogma. Deficiencies of vitamin B12 and vitamin A, but not of iron or folic acid, are associated with severe anaemia. Bacterial infections and, in very young children, hookworm infections are also common in severe anaemia. Irrespective of the aetiology, the mechanism causing severe anaemia is often red cell production failure. Severe anaemia in Africa is therefore a complex multi-factorial syndrome, which, even in an individual patient, is unlikely to be amenable to a single intervention. Policies and practices concerning anaemia diagnosis, treatment and prevention need to be substantially revised if we are to make a significant impact on the huge burden of severe anaemia in Africa.

  20. Acquiring case adaptation knowledge: A hybrid approach

    SciTech Connect

    Leake, D.B.; Kinley, A.; Wilson, D.

    1996-12-31

    The ability of case-based reasoning (CBR) systems to apply cases to novel situations depends on their case adaptation knowledge. However, endowing CBR systems with adequate adaptation knowledge has proven to be a very difficult task. This paper describes a hybrid method for performing case adaptation, using a combination of rule-based and case-based reasoning. It shows how this approach provides a framework for acquiring flexible adaptation knowledge from experiences with autonomous adaptation and suggests its potential as a basis for acquisition of adaptation knowledge from interactive user guidance. It also presents initial experimental results examining the benefits of the approach and comparing the relative contributions of case learning and adaptation learning to reasoning performance.

  1. Acquired immunodeficiency syndrome: Ga-67 citrate imaging

    SciTech Connect

    Woolfenden, J.M.; Carrasquillo, J.A.; Larson, S.M.; Simmons, J.T.; Masur, H.; Smith, P.D.; Shelhamer, J.H.; Ognibene, F.P.

    1987-02-01

    All gallium-67 citrate scans obtained in patients with acquired immunodeficiency syndrome (AIDS) at the Clinical Center, National Institutes of Health (Bethesda, Md.) were retrospectively analyzed and correlated with the results of bronchoscopy, chest radiography, and endoscopy. There were 164 scans of 95 patients. Twenty scans were from patients with Pneumocystis carinii pneumonia; 19 were abnormal, for a sensitivity of 95%. Ga-67 uptake tended to be less in patients receiving therapy for P. carinii pneumonia. Chest radiographs were normal at least initially in three patients with abnormal scans and P. carinii pneumonia. Unusually prominent colonic activity was associated with infection in some patients. No lesions of Kaposi sarcoma showed tracer uptake. Gallium scanning is useful for detecting P. carinii pneumonia and other opportunistic infections in patients with AIDS, but it is not useful for localizing Kaposi sarcoma.

  2. High-resolving mass spectrographs and spectrometers

    NASA Astrophysics Data System (ADS)

    Wollnik, Hermann

    2015-11-01

    Discussed are different types of high resolving mass spectrographs and spectrometers. In detail outlined are (1) magnetic and electric sector field mass spectrographs, which are the oldest systems, (2) Penning Trap mass spectrographs and spectrometers, which have achieved very high mass-resolving powers, but are technically demanding (3) time-of-flight mass spectrographs using high energy ions passing through accelerator rings, which have also achieved very high mass-resolving powers and are equally technically demanding, (4) linear time-of-flight mass spectrographs, which have become the most versatile mass analyzers for low energy ions, while the even higher performing multi-pass systems have only started to be used, (5) orbitraps, which also have achieved remarkably high mass-resolving powers for low energy ions.

  3. Time-Resolved Photoluminescence and Photovoltaics

    SciTech Connect

    Metzger, W. K.; Ahrenkiel, R. K.; Dippo, P.; Geisz, J.; Wanlass, M. W.; Kurtz, S.

    2005-01-01

    The time-resolved photoluminescence (TRPL) technique and its ability to characterize recombination in bulk photovoltaic semiconductor materials are reviewed. Results from a variety of materials and a few recent studies are summarized and compared.

  4. Anodic Polarization Curves Revisited

    ERIC Educational Resources Information Center

    Liu, Yue; Drew, Michael G. B.; Liu, Ying; Liu, Lin

    2013-01-01

    An experiment published in this "Journal" has been revisited and it is found that the curve pattern of the anodic polarization curve for iron repeats itself successively when the potential scan is repeated. It is surprising that this observation has not been reported previously in the literature because it immediately brings into…

  5. Optical polarizer material

    DOEpatents

    Ebbers, Christopher A.

    1999-01-01

    Several crystals have been identified which can be grown using standard single crystals growth techniques and which have a high birefringence. The identified crystals include Li.sub.2 CO.sub.3, LiNaCO.sub.3, LiKCO.sub.3, LiRbCO.sub.3 and LiCsCO.sub.3. The condition of high birefringence leads to their application as optical polarizer materials. In one embodiment of the invention, the crystal has the chemical formula LiK.sub.(1-w-x-y) Na.sub.(1-w-x-z) Rb.sub.(1-w-y-z) Cs.sub.(1-x-y-z) CO.sub.3, where w+x+y+z=1. In another embodiment, the crystalline material may be selected from a an alkali metal carbonate and a double salt of alkali metal carbonates, where the polarizer has a Wollaston configuration, a Glan-Thompson configuration or a Glan-Taylor configuration. A method of making an LiNaCO.sub.3 optical polarizer is described. A similar method is shown for making an LiKCO.sub.3 optical polarizer.

  6. Macrophage activation and polarization.

    PubMed

    Martinez, Fernando Oneissi; Sica, Antonio; Mantovani, Alberto; Locati, Massimo

    2008-01-01

    Macrophages are widely distributed immune system cells that play an indispensable role in homeostasis and defense. They can be phenotypically polarized by the microenvironment to mount specific functional programs. Polarized macrophages can be broadly classified in two main groups: classically activated macrophages (or M1), whose prototypical activating stimuli are IFNgamma and LPS, and alternatively activated macrophages (or M2), further subdivided in M2a (after exposure to IL-4 or IL-13), M2b (immune complexes in combination with IL-1beta or LPS) and M2c (IL-10, TGFbeta or glucocorticoids). M1 exhibit potent microbicidal properties and promote strong IL-12-mediated Th1 responses, whilst M2 support Th2-associated effector functions. Beyond infection M2 polarized macrophages play a role in resolution of inflammation through high endocytic clearance capacities and trophic factor synthesis, accompanied by reduced pro-inflammatory cytokine secretion. Similar functions are also exerted by tumor-associated macrophages (TAM), which also display an alternative-like activation phenotype and play a detrimental pro-tumoral role. Here we review the main functions of polarized macrophages and discuss the perspectives of this field.

  7. The polarized EMC effect

    SciTech Connect

    W. Bentz; I. C. Cloet; A. W. Thomas

    2007-02-01

    We calculate both the spin independent and spin dependent nuclear structure functions in an effective quark theory. The nucleon is described as a composite quark-diquark state, and the nucleus is treated in the mean field approximation. We predict a sizable polarized EMC effect, which could be confirmed in future experiments.

  8. Variable polarity arc welding

    NASA Technical Reports Server (NTRS)

    Bayless, E. O., Jr.

    1991-01-01

    Technological advances generate within themselves dissatisfactions that lead to further advances in a process. A series of advances in welding technology which culminated in the Variable Polarity Plasma Arc (VPPA) Welding Process and an advance instituted to overcome the latest dissatisfactions with the process: automated VPPA welding are described briefly.

  9. North Polar Ice Cap

    NASA Technical Reports Server (NTRS)

    1997-01-01

    North polar ice cap of Mars, as seen during mid summer in the northern hemisphere. The reddish areas consist of eolian dust, bright white areas consist of a mixture of water ice and dust, and the dark blue areas consist of sand dunes forming a huge 'collar' around the polar ice cap. (The colors have been enhanced with a decorrelation stretch to better show the color variability.) Shown here is an oblique view of the polar region, as seen with the Viking 1 spacecraft orbiting Mars over latitude 39 degrees north. The spiral bands consist of valleys which form by a combination of the Coriolis forces, wind erosion, and differential sublimation and condensation. In high-resolution images the polar caps are seen to consist of thick sequences of layered deposits, suggesting that cyclical climate changes have occurred on Mars. Cyclical climate changes are readily explained by quasi-periodic changes in the amount and distribution of solar heating resulting from perturbations in orbital and axial elements. Variations in the Earth's orbit have also been linked to the terrestrial climate changes during the ice ages.

  10. Optical polarizer material

    SciTech Connect

    Ebbers, C.A.

    1999-08-31

    Several crystals have been identified which can be grown using standard single crystals growth techniques and which have a high birefringence. The identified crystals include Li.sub.2 CO.sub.3, LiNaCO.sub.3, LiKCO.sub.3, LiRbCO.sub.3 and LiCsCO.sub.3. The condition of high birefringence leads to their application as optical polarizer materials. In one embodiment of the invention, the crystal has the chemical formula LiK.sub.(1-w-x-y) Na.sub.(1-w-x-z) Rb.sub.(1-w-y-z) Cs.sub.(1-x-y-z) CO.sub.3, where w+x+y+z=1. In another embodiment, the crystalline material may be selected from a an alkali metal carbonate and a double salt of alkali metal carbonates, where the polarizer has a Wollaston configuration, a Glan-Thompson configuration or a Glan-Taylor configuration. A method of making an LiNaCO.sub.3 optical polarizer is described. A similar method is shown for making an LiKCO.sub.3 optical polarizer.

  11. Titan Polar Landscape Evolution

    NASA Technical Reports Server (NTRS)

    Moore, Jeffrey M.

    2016-01-01

    With the ongoing Cassini-era observations and studies of Titan it is clear that the intensity and distribution of surface processes (particularly fluvial erosion by methane and Aeolian transport) has changed through time. Currently however, alternate hypotheses substantially differ among specific scenarios with respect to the effects of atmospheric evolution, seasonal changes, and endogenic processes. We have studied the evolution of Titan's polar region through a combination of analysis of imaging, elevation data, and geomorphic mapping, spatially explicit simulations of landform evolution, and quantitative comparison of the simulated landscapes with corresponding Titan morphology. We have quantitatively evaluated alternate scenarios for the landform evolution of Titan's polar terrain. The investigations have been guided by recent geomorphic mapping and topographic characterization of the polar regions that are used to frame hypotheses of process interactions, which have been evaluated using simulation modeling. Topographic information about Titan's polar region is be based on SAR-Topography and altimetry archived on PDS, SAR-based stereo radar-grammetry, radar-sounding lake depth measurements, and superposition relationships between geomorphologic map units, which we will use to create a generalized topographic map.

  12. Classical Demonstration of Polarization.

    ERIC Educational Resources Information Center

    Bauman, Robert P.; Moore, Dennis R.

    1980-01-01

    Presents a classical demonstration of polarization for high school students. The initial state of this model, which demonstrates the important concepts of the optical and quantum problems, was developed during the 1973 summer program on lecture demonstration at the U.S. Naval Academy. (HM)

  13. Fast, high-fidelity, all-optical and dynamically-controlled polarization gate using room-temperature atomic vapor

    SciTech Connect

    Li, Runbing; Zhu, Chengjie; Deng, L.; Hagley, E. W.

    2014-10-20

    We demonstrate a fast, all-optical polarization gate in a room-temperature atomic medium. Using a Polarization-Selective-Kerr-Phase-Shift (PSKPS) technique, we selectively write a π phase shift to one circularly-polarized component of a linearly-polarized input signal field. The output signal field maintains its original strength but acquires a 90° linear polarization rotation, demonstrating fast, high-fidelity, dynamically-controlled polarization gate operation. The intensity of the polarization-switching field used in this PKSPK-based polarization gate operation is only 2 mW/cm{sup 2}, which would be equivalent to 0.5 nW of light power (λ = 800 nm) confined in a typical commercial photonic hollow-core fiber. This development opens a realm of possibilities for potential future extremely low light level telecommunication and information processing systems.

  14. Guidelines for prevention of hospital acquired infections

    PubMed Central

    Mehta, Yatin; Gupta, Abhinav; Todi, Subhash; Myatra, SN; Samaddar, D. P.; Patil, Vijaya; Bhattacharya, Pradip Kumar; Ramasubban, Suresh

    2014-01-01

    These guidelines, written for clinicians, contains evidence-based recommendations for the prevention of hospital acquired infections Hospital acquired infections are a major cause of mortality and morbidity and provide challenge to clinicians. Measures of infection control include identifying patients at risk of nosocomial infections, observing hand hygiene, following standard precautions to reduce transmission and strategies to reduce VAP, CR-BSI, CAUTI. Environmental factors and architectural lay out also need to be emphasized upon. Infection prevention in special subsets of patients - burns patients, include identifying sources of organism, identification of organisms, isolation if required, antibiotic prophylaxis to be used selectively, early removal of necrotic tissue, prevention of tetanus, early nutrition and surveillance. Immunodeficient and Transplant recipients are at a higher risk of opportunistic infections. The post tranplant timetable is divided into three time periods for determining risk of infections. Room ventilation, cleaning and decontamination, protective clothing with care regarding food requires special consideration. Monitoring and Surveillance are prioritized depending upon the needs. Designated infection control teams should supervise the process and help in collection and compilation of data. Antibiotic Stewardship Recommendations include constituting a team, close coordination between teams, audit, formulary restriction, de-escalation, optimizing dosing, active use of information technology among other measure. The recommendations in these guidelines are intended to support, and not replace, good clinical judgment. The recommendations are rated by a letter that indicates the strength of the recommendation and a Roman numeral that indicates the quality of evidence supporting the recommendation, so that readers can ascertain how best to apply the recommendations in their practice environments. PMID:24701065

  15. Community-Acquired Pneumonia in Latin America.

    PubMed

    Iannella, Hernán A; Luna, Carlos M

    2016-12-01

    Community-acquired pneumonia (CAP) is associated with significant morbidity and mortality in Latin America and the Caribbean (LAC) region. Poverty, socioeconomic factors, and malnutrition influence the incidence and outcome of CAP in LAC. In LAC, Streptococcus pneumoniae is the most frequent microorganism responsible for CAP, (incidence: 24-78%); the incidence of atypical microorganisms is similar to other regions of the world. Human immunodeficiency virus (HIV)/acquired immunodeficiency syndrome (AIDS) is a growing problem in the LAC region, with the Caribbean being the second most affected area worldwide after Sub-Saharan Africa. Pneumococcal pneumonia remains the most common cause of CAP in HIV-infected patients, but Pneumocystis jirovecii and tuberculosis (TB) are also common in this population. The heterogeneity of the health care systems and social inequity between different countries in LAC, and even between different settings inside the same country, is a difficult issue. TB, including multidrug-resistant TB, is several times more common in South American and Central American countries compared with North America. Furthermore, hantaviruses circulating in the Americas (new world hantaviruses) generate a severe respiratory disease called hantavirus pulmonary syndrome, with an associated mortality as high as 50%. More than 30 hantaviruses have been reported in the Western Hemisphere, with more frequent cases registered in the southern cone (Argentina, Chile, Uruguay, Paraguay, Bolivia, and Brazil). Respiratory viruses (particularly influenza) remain an important cause of morbidity and mortality, particularly in the elderly. Low rates of vaccination (against influenza as well as pneumococcus) may heighten the risk of these infections in low- and middle-income countries.

  16. RESOLVE: Bridge between early lunar ISRU and science objectives

    NASA Astrophysics Data System (ADS)

    Taylor, G.; Sanders, G.; Larson, W.; Johnson, K.

    2007-08-01

    interstellar volatiles from cold molecular clouds. These sources leave distinctive signatures, many detectable by RESOLVE. Comet impacts are likely to produce coherent layers of ice (probably reduced to pebbles and boulders by subsequent small impacts, and buried); these would be detected by imaging and Raman spectroscopy, the high water (H2O) signal measured by the GC, and possibly by changes in the drilling rate or torque. More continuous delivery mechanism theories would not produce layers or boulders of ice, but might bond regolith grains together. Continuous sources might be distinguished by H/H2O ratios and the abundances of other volatiles. Hydrogen isotopic composition would provide additional important information because these sources have distinctive D/H ratios, so one enhancement to RESOLVE would be an incorporation of a mass spectrometer with the existing GC. Reactions in the Polar Regolith: Billions of years of micrometeorite bombardment, irradiation by cosmic rays and interstellar Lyman-alpha ultraviolet, and the presence of carbon-, hydrogen-, oxygen-, and nitrogen-bearing volatiles might have led to the production of organic compounds, a process that has been demonstrated experimentally. Heating by micrometeorite impacts might drive reactions involving water to produce phyllosilicates (clay minerals). If abundant enough, these reaction products could be observable by Raman spectroscopy and GC analysis. Thus, the polar cold traps are natural laboratories for the study of processes operating in interstellar space, and the RESOLVE suite of instruments can shed light on those processes.

  17. Lunar Polar Coring Lander

    NASA Technical Reports Server (NTRS)

    Angell, David; Bealmear, David; Benarroche, Patrice; Henry, Alan; Hudson, Raymond; Rivellini, Tommaso; Tolmachoff, Alex

    1990-01-01

    Plans to build a lunar base are presently being studied with a number of considerations. One of the most important considerations is qualifying the presence of water on the Moon. The existence of water on the Moon implies that future lunar settlements may be able to use this resource to produce things such as drinking water and rocket fuel. Due to the very high cost of transporting these materials to the Moon, in situ production could save billions of dollars in operating costs of the lunar base. Scientists have suggested that the polar regions of the Moon may contain some amounts of water ice in the regolith. Six possible mission scenarios are suggested which would allow lunar polar soil samples to be collected for analysis. The options presented are: remote sensing satellite, two unmanned robotic lunar coring missions (one is a sample return and one is a data return only), two combined manned and robotic polar coring missions, and one fully manned core retrieval mission. One of the combined manned and robotic missions has been singled out for detailed analysis. This mission proposes sending at least three unmanned robotic landers to the lunar pole to take core samples as deep as 15 meters. Upon successful completion of the coring operations, a manned mission would be sent to retrieve the samples and perform extensive experiments of the polar region. Man's first step in returning to the Moon is recommended to investigate the issue of lunar polar water. The potential benefits of lunar water more than warrant sending either astronauts, robots or both to the Moon before any permanent facility is constructed.

  18. A Method of Resolving the 180-Degree Ambiguity by Employing the Chirality of Solar Features

    NASA Astrophysics Data System (ADS)

    Martin, S. F.; Lin, Y.; Engvold, O.

    2008-07-01

    The 180-degree ambiguity in magnetic field direction along polarity reversal boundaries can be resolved often and reliably by the chiral method. The chiral method requires (1) identification of the chirality of at least one solar feature related to a polarity reversal boundary along which the field direction is sought and (2) knowledge of the polarity of the network magnetic field on at least one side of the polarity reversal boundary. In the context of the Sun, chirality is an observable signature of the handedness of the magnetic field of a solar feature. We concentrate on how to determine magnetic field direction from chirality definitions and illustrate the technique in eight examples. The examples cover the spectrum of polarity boundaries associated with filament channels and filaments ranging from those connected with active regions to those on the quiet Sun. The applicability of the chiral method to all categories of filaments supports the view that active region filaments and quiescent filaments are the extreme ends in a continuous spectrum of filaments. The chiral method is almost universally applicable because many types of solar features that reveal chirality are now readily seen in solar images accessible over the World Wide Web; also there are clear differences between left-handed and right-handed solar structures that can be identified in both high- and low-resolution data although high-resolution images are almost always preferable. In addition to filaments and filament channels, chirality is identifiable in coronal loop systems, flare loop systems, sigmoids, some sunspots, and some erupting prominences. Features other than filament channels and filaments can be used to resolve the 180-degree ambiguity because there is a one-to-one relationship between the chiralities of all features associated with a given polarity reversal boundary.

  19. Interplanetary magnetic sector polarity inferred from polar geomagnetic field observations

    NASA Technical Reports Server (NTRS)

    Eriss-Christensen, E.; Lassen, K.; Wilcox, J. M.; Gonzalez, W.; Colburn, D. S.

    1971-01-01

    With the use of a prediction technique it is shown that the polarity (toward or away from the sun) of the interplanetary magnetic field can be reliably inferred from observations of the polar geomagnetic field.

  20. Honeybee navigation: critically examining the role of the polarization compass

    PubMed Central

    Evangelista, C.; Kraft, P.; Dacke, M.; Labhart, T.; Srinivasan, M. V.

    2014-01-01

    Although it is widely accepted that honeybees use the polarized-light pattern of the sky as a compass for navigation, there is little direct evidence that this information is actually sensed during flight. Here, we ask whether flying bees can obtain compass cues derived purely from polarized light, and communicate this information to their nest-mates through the ‘waggle dance’. Bees, from an observation hive with vertically oriented honeycombs, were trained to fly to a food source at the end of a tunnel, which provided overhead illumination that was polarized either parallel to the axis of the tunnel, or perpendicular to it. When the illumination was transversely polarized, bees danced in a predominantly vertical direction with waggles occurring equally frequently in the upward or the downward direction. They were thus using the polarized-light information to signal the two possible directions in which they could have flown in natural outdoor flight: either directly towards the sun, or directly away from it. When the illumination was axially polarized, the bees danced in a predominantly horizontal direction with waggles directed either to the left or the right, indicating that they could have flown in an azimuthal direction that was 90° to the right or to the left of the sun, respectively. When the first half of the tunnel provided axial illumination and the second half transverse illumination, bees danced along all of the four principal diagonal directions, which represent four equally likely locations of the food source based on the polarized-light information that they had acquired during their journey. We conclude that flying bees are capable of obtaining and signalling compass information that is derived purely from polarized light. Furthermore, they deal with the directional ambiguity that is inherent in polarized light by signalling all of the possible locations of the food source in their dances, thus maximizing the chances of recruitment to it. PMID