Middle atmosphere measurements of small-scale electron density irregularities and ion properties during the MAC/Epsilon campaign

NASA Technical Reports Server (NTRS)

Blood, S. P.; Mitchell, J. D.; Croskey, C. L.

1989-01-01

Rocket payloads designed to measure small scale electron density irregularities and ion properties in the middle atmosphere were flown with each of the three main salvos of the MAC/Epsilon campaign conducted at the Andoya Rocket Range, Norway, during October to November 1987. Fixed bias, hemispheric nose tip probes measured small scale electron density irregularities, indicative of neutral air turbulence, during the rocket's ascent; and subsequently, parachute-borne Gerdien condensers measured the region's polar electrical conductivity, ion mobility and density. One rocket was launched during daylight (October 15, 1052:20 UT), and the other two launches occurred at night (October 21, 2134 UT: November 12, 0021:40 UT) under moderately disturbed conditions which enhanced the detection and measurement of turbulence structures. A preliminary analysis of the real time data displays indicates the presence of small scale electron density irregularities in the altitude range of 60 to 90 km. Ongoing data reduction will determine turbulence parameters and also the region's electrical properties below 90 km.

Post-midnight equatorial irregularity distributions and vertical drift velocity variations during solstices

NASA Astrophysics Data System (ADS)

Su, S.-Y.; Liu, C. H.; Chao, C.-K.

2018-04-01

Longitudinal distributions of post-midnight equatorial ionospheric irregularity occurrences observed by ROCSAT-1 (1st satellite of the Republic of China) during moderate to high solar activity years in two solstices are studied with respect to the vertical drift velocity and density variations. The post-midnight irregularity distributions are found to be similar to the well-documented pre-midnight ones, but are different from some published distributions taken during solar minimum years. Even though the post-midnight ionosphere is sinking in general, longitudes of frequent positive vertical drift and high density seems to coincide with the longitudes of high irregularity occurrences. Large scatters found in the vertical drift velocity and density around the dip equator in different ROCSAT-1 orbits indicate the existence of large and frequent variations in the vertical drift velocity and density that seem to be able to provide sufficient perturbations for the Rayleigh-Taylor (RT) instability to cause the irregularity occurrences. The need of seeding agents such as gravity waves from atmospheric convective clouds to initiate the Rayleigh-Taylor instability may not be necessary.

On the spatial distribution of decameter‒scale subauroral ionospheric irregularities observed by SuperDARN radars

NASA Astrophysics Data System (ADS)

Larquier, S.; Ponomarenko, P.; Ribeiro, A. J.; Ruohoniemi, J. M.; Baker, J. B. H.; Sterne, K. T.; Lester, M.

2013-08-01

The midlatitude Super Dual Auroral Radar Network (SuperDARN) radars regularly observe nighttime low‒velocity Sub‒Auroral Ionospheric Scatter (SAIS) from decameter‒scale ionospheric density irregularities during quiet geomagnetic conditions. To establish the origin of the density irregularities responsible for low‒velocity SAIS, it is necessary to distinguish between the effects of high frequency (HF) propagation and irregularity occurrence itself on the observed backscatter distribution. We compare range, azimuth, and elevation data from the Blackstone SuperDARN radar with modeling results from ray tracing coupled with the International Reference Ionosphere assuming a uniform irregularity distribution. The observed and modeled distributions are shown to be very similar. The spatial distribution of backscattering is consistent with the requirement that HF rays propagate nearly perpendicular to the geomagnetic field lines (aspect angle ≤1°). For the first time, the irregularities responsible for low‒velocity SAIS are determined to extend between 200 and 300 km altitude, validating previous assumptions that low‒velocity SAIS is an F‒region phenomenon. We find that the limited spatial extent of this category of ionospheric backscatter within SuperDARN radars' fields‒of‒view is a consequence of HF propagation effects and the finite vertical extent of the scattering irregularities. We conclude that the density irregularities responsible for low‒velocity SAIS are widely distributed horizontally within the midlatitude ionosphere but are confined to the bottom‒side F‒region.

Highly Structured Plasma Density and Associated Electric and Magnetic Field Irregularities at Sub-Auroral, Middle, and Low Latitudes in the Topside Ionosphere Observed with the DEMETER and DMSP Satellites

NASA Technical Reports Server (NTRS)

Pfaff, Robert F.; Liebrecht, C; Berthelier, Jean-Jacques; Parrot, M.; Lebreton, Jean-Pierre

2007-01-01

Detailed observations of the plasma structure and irregularities that characterize the topside ionosphere at sub-auroral, middle, and low-latitudes are gathered with probes on the DEMETER and DMSP satellites. In particular, we present DEMETER observations near 700 km altitude that reveal: (1) the electric field irregularities and density depletions at mid-latitudes are remarkably similar to those associated with equatorial spread-F at low latitudes; (2) the mid-latitude density structures contain both depletions and enhancements with scale lengths along the spacecraft trajectory that typically vary from 10's to 100's of km; (3) in some cases, ELF magnetic field irregularities are observed in association with the electric field irregularities on the walls of the plasma density structures and appear to be related to finely-structured spatial currents and/or Alfven waves; (4) during severe geomagnetic storms, broad regions of nightside plasma density structures are typically present, in some instances extending from the equator to the subauroral regions; and (5) intense, broadband electric and magnetic field irregularities are observed at sub-auroral latitudes during geomagnetic storm periods that are typically associated with the trough region. Data from successive DEMETER orbits during storm periods in both the daytime and nighttime illustrate how enhancements of both the ambient plasma density, as well as sub-auroral and mid-latitude density structures, correlate and evolve with changes in the Dst. The DEMETER data are compared with near simultaneous observations gathered by the DMSP satellites near 840 km. The observations are related to theories of sub-auroral and mid-latitude plasma density structuring during geomagnetic storms and penetration electric fields and are highly germane to understanding space weather effects regarding disruption of communication and navigation signals in the near-space environment.

Analysis of Mid-Latitude Plasma Density Irregularities in the Presence of Finite Larmor Radius Effects

NASA Astrophysics Data System (ADS)

Sotnikov, V. I.; Kim, T. C.; Mishin, E. V.; Kil, H.; Kwak, Y. S.; Paraschiv, I.

2017-12-01

Ionospheric irregularities cause scintillations of electromagnetic signals that can severely affect navigation and transionospheric communication, in particular during space storms. At mid-latitudes the source of F-region Field Aligned Irregularities (FAI) is yet to be determined. They can be created in enhanced subauroral flow channels (SAI/SUBS), where strong gradients of electric field, density and plasma temperature are present. Another important source of FAI is connected with Medium-scale travelling ionospheric disturbances (MSTIDs). Related shear flows and plasma density troughs point to interchange and Kelvin-Helmholtz type instabilities as a possible source of plasma irregularities. A model of nonlinear development of these instabilities based on the two-fluid hydrodynamic description with inclusion of finite Larmor radius effects will be presented. This approach allows to resolve density irregularities on the meter scale. A numerical code in C language to solve the derived nonlinear equations for analysis of interchange and flow velocity shear instabilities in the ionosphere was developed. This code will be used to analyze competition between interchange and Kelvin-Helmholtz instabilities in the mid-latitude region. The high-resolution simulations with continuous density and velocity profiles will be driven by the ambient conditions corresponding to the in situ data obtained during the 2016 Daejeon (Korea) and MU (Japan) radar campaign and data collected simultaneously by the Swarm satellites passed over Korea and Japan. PA approved #: 88ABW-2017-3641

Pleural irregularities and mediastinal pleural involvement in early stages of malignant pleural mesothelioma and benign asbestos pleural effusion.

PubMed

Kato, Katsuya; Gemba, Kenichi; Fujimoto, Nobukazu; Aoe, Keisuke; Takeshima, Yukio; Inai, Kouki; Kishimoto, Takumi

2016-09-01

To elucidate differences in the level and localization of pleural irregularities in early malignant pleural mesothelioma (eMPM) and benign asbestos pleural effusion (BAPE) using CT. Retrospective assessment of CT findings of consecutive patients with BAPE at a single centre and patients with eMPM reported in Japanese vital statistics. Thirty-six patients with confirmed diagnoses of BAPE and sixty-six patients with confirmed diagnoses of eMPM (mesothelioma stages T1 or T2) were included. Informed consent, CT scans, and clinical and pathologic details were obtained for all patients and were reviewed by one radiologist, two pathologists, and two pulmonologists. Asbestosis, pleural plaque, rounded atelectasis, and diffuse pleural thickening were assessed in all patients. Prevalence of asbestosis, pleural plaque, rounded atelectasis, and diffuse pleural thickening was significantly higher in the BAPE group. Low-level irregularity was more common in the BAPE group (p<0.001), whereas high-level irregularity, mediastinal localization, and interlobar fissure were more prevalent in the eMPM group (p<0.001). Interlobar pleural irregularity was not observed in any patients in the BAPE group, although 55% of patients in the eMPM group showed interlobar pleural irregularity. Mediastinal pleural involvement was observed in 74% of patients in the eMPM group and had a positive predictive value of 89%. This study demonstrates that the level and localization of plural irregularities significantly differed between patients with BAPE and eMPM. Large-scale prospective studies are needed to fully establish the diagnostic utility of such differences. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

Ionospheric chemical releases

NASA Technical Reports Server (NTRS)

Bernhardt, Paul A.; Scales, W. A.

1990-01-01

Ionospheric plasma density irregularities can be produced by chemical releases into the upper atmosphere. F-region plasma modification occurs by: (1) chemically enhancing the electron number density; (2) chemically reducing the electron population; or (3) physically convecting the plasma from one region to another. The three processes (production, loss, and transport) determine the effectiveness of ionospheric chemical releases in subtle and surprising ways. Initially, a chemical release produces a localized change in plasma density. Subsequent processes, however, can lead to enhanced transport in chemically modified regions. Ionospheric modifications by chemical releases excites artificial enhancements in airglow intensities by exothermic chemical reactions between the newly created plasma species. Numerical models were developed to describe the creation and evolution of large scale density irregularities and airglow clouds generated by artificial means. Experimental data compares favorably with theses models. It was found that chemical releases produce transient, large amplitude perturbations in electron density which can evolve into fine scale irregularities via nonlinear transport properties.

Small-scale plasma irregularities in the nightside Venus ionosphere

NASA Astrophysics Data System (ADS)

Grebowsky, J. M.; Curtis, S. A.; Brace, L. H.

1991-12-01

The individual volt-ampere curves from the Pioneer Venus Orbiter electron temperature probe showed evidence for small-scale density irregularities, or short-period plasma waves, in regions of the nightside ionosphere where the Orbiter electric field detector observed waves in its 100-Hz channel. A survey of the nightside volt-ampere curves has revealed several hundred examples of such irregularities. The I-V structures correspond to plasma density structure with spatial scale sizes in the range of about 100-2000 m, or alternatively they could be viewed as waves having frequencies extending toward 100 Hz. They are often seen as isolated events, with spatial extent along the orbit frequently less than 80 km. The density irregularities or waves occur in or near prominent gradients in the ambient plasma concentrations both at low altitudes where molecular ions are dominant and at higher altitudes in regions of reduced plasma density where O(+) is the major ion. Electric field 100-Hz bursts occur simultaneously, with the majority of the structured I-V curves providing demonstrative evidence that at least some of the E field signals are produced within the ionosphere.

Diagnostics of a large-scale irregularity in the electron density near the boundary of the radio transparency frequency range of the ionosphere

NASA Astrophysics Data System (ADS)

Afanasiev, N. T.; Markov, V. P.

2011-08-01

Approximate functional relationships for the calculation of a disturbed transionogram with a trace deformation caused by the influence of a large-scale irregularity in the electron density are obtained. Numerical and asymptotic modeling of disturbed transionograms at various positions of a spacecraft relative to a ground-based observation point is performed. A possibility of the determination of the intensity and dimensions of a single large-scale irregularity near the boundary of the radio transparency frequency range of the ionosphere is demonstrated.

Rocket measurements of electron density irregularities during MAC/SINE

NASA Technical Reports Server (NTRS)

Ulwick, J. C.

1989-01-01

Four Super Arcas rockets were launched at the Andoya Rocket Range, Norway, as part of the MAC/SINE campaign to measure electron density irregularities with high spatial resolution in the cold summer polar mesosphere. They were launched as part of two salvos: the turbulent/gravity wave salvo (3 rockets) and the EISCAT/SOUSY radar salvo (one rocket). In both salvos meteorological rockets, measuring temperature and winds, were also launched and the SOUSY radar, located near the launch site, measured mesospheric turbulence. Electron density irregularities and strong gradients were measured by the rocket probes in the region of most intense backscatter observed by the radar. The electron density profiles (8 to 4 on ascent and 4 on descent) show very different characteristics in the peak scattering region and show marked spatial and temporal variability. These data are intercompared and discussed.

Intermediate scale plasma density irregularities in the polar ionosphere inferred from radio occultation

NASA Astrophysics Data System (ADS)

Shume, E. B.; Komjathy, A.; Langley, R. B.; Verkhoglyadova, O. P.; Butala, M.; Mannucci, A. J.

2014-12-01

In this research, we report intermediate scale plasma density irregularities in the high-latitude ionosphere inferred from high-resolution radio occultation (RO) measurements in the CASSIOPE (CAScade Smallsat and IOnospheric Polar Explorer) - GPS (Global Positioning System) satellites radio link. The high inclination of the CASSIOPE satellite and high rate of signal receptionby the occultation antenna of the GPS Attitude, Positioning and Profiling (GAP) instrument on the Enhanced Polar Outflow Probe platform on CASSIOPE enable a high temporal and spatial resolution investigation of the dynamics of the polar ionosphere, magnetosphere-ionospherecoupling, solar wind effects, etc. with unprecedented details compared to that possible in the past. We have carried out high spatial resolution analysis in altitude and geomagnetic latitude of scintillation-producing plasma density irregularities in the polar ionosphere. Intermediate scale, scintillation-producing plasma density irregularities, which corresponds to 2 to 40 km spatial scales were inferred by applying multi-scale spectral analysis on the RO phase delay measurements. Using our multi-scale spectral analysis approach and Polar Operational Environmental Satellites (POES) and Defense Meteorological Satellite Program (DMSP) observations, we infer that the irregularity scales and phase scintillations have distinct features in the auroral oval and polar cap regions. In specific terms, we found that large length scales and and more intense phase scintillations are prevalent in the auroral oval compared to the polar cap region. Hence, the irregularity scales and phase scintillation characteristics are a function of the solar wind and the magnetospheric forcing. Multi-scale analysis may become a powerful diagnostic tool for characterizing how the ionosphere is dynamically driven by these factors.

Direct evidence of double-slope power spectra in the high-latitude ionospheric plasma

NASA Astrophysics Data System (ADS)

Spicher, A.; Miloch, W. J.; Moen, J. I.

2014-03-01

We report direct observations of the double-slope power spectra for plasma irregularities in the F layer of the polar ionosphere. The investigation of cusp irregularities ICI-2 sounding rocket, which was launched into the polar cusp ionosphere, intersected enhanced plasma density regions with decameter-scale irregularities. Density measurements at unprecedented high resolution with multi-Needle Langmuir Probes allowed for a detailed study of the plasma irregularities down to kinetic scales. Spectral analysis reveals double-slope power spectra for regions of enhanced fluctuations associated mainly with density gradients, with the steepening of the spectra occurring close to the oxygen gyrofrequency. These findings are further supported with the first results from the ICI-3 rocket, which flew through regions with strong precipitation and velocity shears. Previously, double-slope spectra have been observed in the equatorial ionosphere. The present work gives a direct evidence that the double-slope power spectra can be common in the high-latitude ionosphere.

Influence of Stress Connected with Moving to a New Farm on Potentially MAP-Infected Mouflons.

PubMed

Pribylova-Dziedzinska, Radka; Slana, Iva; Lamka, Jiri; Pavlik, Ivo

2014-01-01

There is no European legislation concerning paratuberculosis that requires that imported animals be kept in quarantine and commonly they are directly released into areas with other animals. In this study, detection of latent infection of paratuberculosis in healthy mouflons previously diagnosed as paratuberculosis-free, but originating from a real time quantitative PCR- (qPCR-) positive herd, occurred after their transport to a new farm. During a twelve-day quarantine period, all mouflons irregularly shed Mycobacterium avium subsp. paratuberculosis (MAP) in faeces, and in a small number of cases also in milk. After the animals were released from quarantine, MAP was detected for a further two days, after which, testing was negative, except in one case. Therefore, the stress connected with transport, novel environment, dietary change, or limited area with high density of animals might have contributed to the induction of paratuberculosis and the shedding of MAP from the animals, previously diagnosed as MAP-negative. According to these results, the keeping of imported animals in quarantine and their examination for MAP presence not only before the transport but also afterwards should be recommended. The designation of a particular area of a farm as a quarantine enclosure could help to mitigate the impact of stress caused by a confined space with a high density of animals.

Design Optimization of Irregular Cellular Structure for Additive Manufacturing

NASA Astrophysics Data System (ADS)

Song, Guo-Hua; Jing, Shi-Kai; Zhao, Fang-Lei; Wang, Ye-Dong; Xing, Hao; Zhou, Jing-Tao

2017-09-01

Irregularcellular structurehas great potential to be considered in light-weight design field. However, the research on optimizing irregular cellular structures has not yet been reporteddue to the difficulties in their modeling technology. Based on the variable density topology optimization theory, an efficient method for optimizing the topology of irregular cellular structures fabricated through additive manufacturing processes is proposed. The proposed method utilizes tangent circles to automatically generate the main outline of irregular cellular structure. The topological layoutof each cellstructure is optimized using the relative density informationobtained from the proposed modified SIMP method. A mapping relationship between cell structure and relative densityelement is builtto determine the diameter of each cell structure. The results show that the irregular cellular structure can be optimized with the proposed method. The results of simulation and experimental test are similar for irregular cellular structure, which indicate that the maximum deformation value obtained using the modified Solid Isotropic Microstructures with Penalization (SIMP) approach is lower 5.4×10-5 mm than that using the SIMP approach under the same under the same external load. The proposed research provides the instruction to design the other irregular cellular structure.

New Model for Ionospheric Irregularities at Mars

NASA Astrophysics Data System (ADS)

Keskinen, M. J.

2018-03-01

A new model for ionospheric irregularities at Mars is presented. It is shown that wind-driven currents in the dynamo region of the Martian ionosphere can be unstable to the electromagnetic gradient drift instability. This plasma instability can generate ionospheric density and magnetic field irregularities with scale sizes of approximately 15-20 km down to a few kilometers. We show that the instability-driven magnetic field fluctuation amplitudes relative to background are correlated with the ionospheric density fluctuation amplitudes relative to background. Our results can explain recent observations made by the Mars Atmosphere and Volatile EvolutioN spacecraft in the Martian ionosphere dynamo region.

New advantages of the combined GPS and GLONASS observations for high-latitude ionospheric irregularities monitoring: case study of June 2015 geomagnetic storm

NASA Astrophysics Data System (ADS)

Cherniak, Iurii; Zakharenkova, Irina

2017-05-01

Monitoring, tracking and nowcasting of the ionospheric plasma density disturbances using dual-frequency measurements of the Global Positioning System (GPS) signals are effectively carried out during several decades. Recent rapid growth and modernization of the ground-based segment gives an opportunity to establish a great database consisting of more than 6000 stations worldwide which provide GPS signals measurements with an open access. Apart of the GPS signals, at least two-third of these stations receive simultaneously signals transmitted by another Global Navigation Satellite System (GNSS)—the Russian system GLONASS. Today, GLONASS signal measurements are mainly used in navigation and geodesy only and very rarely for ionosphere research. We present the first results demonstrating advantages of using several independent but compatible GNSS systems like GPS and GLONASS for improvement of the permanent monitoring of the high-latitude ionospheric irregularities. For the first time, the high-resolution two-dimensional maps of ROTI perturbation were made using not only GPS but also GLONASS measurements. We extend the use of the ROTI maps for analyzing ionospheric irregularities distribution. We demonstrate that the meridional slices of the ROTI maps can be effectively used to study the occurrence and temporal evolution of the ionospheric irregularities. The meridional slices of the geographical sectors with a high density of the GPS and GLONASS measurements can represent spatio-temporal dynamics of the intense ionospheric plasma density irregularities with very high resolution, and they can be effectively used for detailed study of the space weather drivers on the processes of the ionospheric irregularities generation, development and their lifetimes. Using a representative database of 5800 ground-based GNSS stations located worldwide, we have investigated the occurrence of the high-latitude ionospheric plasma density irregularities during the geomagnetic storm of June 22-23, 2015.[Figure not available: see fulltext.

Low and Midlatitude Ionospheric Plasma Density Irregularities and Their Effects on Geomagnetic Field

NASA Astrophysics Data System (ADS)

Yokoyama, Tatsuhiro; Stolle, Claudia

2017-03-01

Earth's magnetic field results from various internal and external sources. The electric currents in the ionosphere are major external sources of the magnetic field in the daytime. High-resolution magnetometers onboard low-Earth-orbit satellites such as CHAMP and Swarm can detect small-scale currents in the nighttime ionosphere, where plasma density gradients often become unstable and form irregular density structures. The magnetic field variations caused by the ionospheric irregularities are comparable to that of the lithospheric contribution. Two phenomena in the nighttime ionosphere that contribute to the magnetic field variation are presented: equatorial plasma bubble (EPB) and medium-scale traveling ionospheric disturbance (MSTID). EPB is formed by the generalized Rayleigh-Taylor instability over the dip equator and grows nonlinearly to as high as 2000 km apex altitude. It is characterized by deep plasma density depletions along magnetic flux tubes, where the diamagnetic effect produced by a pressure-gradient-driven current enhances the main field intensity. MSTID is a few hundred kilometer-scale disturbance in the midlatitude ionosphere generated by the coupled electrodynamics between the ionospheric E and F regions. The field-aligned currents associated with EPBs and MSTIDs also have significant signatures in the magnetic field perpendicular to the main field direction. The empirical discovery of the variations in the magnetic field due to plasma irregularities has motivated the inclusion of electrodynamics in the physical modeling of these irregularities. Through an effective comparison between the model results and observations, the physical process involved has been largely understood. The prediction of magnetic signatures due to plasma irregularities has been advanced by modeling studies, and will be helpful in interpreting magnetic field observations from satellites.

Ultrasound variants of autoimmune thyroiditis in children and adolescents and their clinical implication in relation to papillary thyroid carcinoma development.

PubMed

Januś, D; Wójcik, M; Drabik, G; Wyrobek, Ł; Starzyk, J B

2018-03-01

The prevalence of autoimmune thyroiditis (AIT) and papillary thyroid carcinoma (PTC) is rising in children and adolescents, and the coincidence of AIT and PTC is as high as 6.3-43%. To investigate the ultrasound manifestation of AIT in relation to PTC development in paediatric patients. 179 paediatric patients (133 females), mean (SD) age: 13.9 (3.03) years diagnosed with AIT and referred for ultrasound evaluation. Eight patients were diagnosed with PTC (6 females). Retrospective analysis of thyroid ultrasound scans of patients diagnosed with AIT. Thyroid and autoimmune status was assessed based on TSH, fT4, fT3 and increased aTPO and/or aTG and/or TRAB levels. In patients with PTC, total thyroidectomy was performed. Analysis of thyroid US scans revealed that the following five ultrasound variants of AIT were observed in 179 patients: the most common in 35.2%-diffuse thyroiditis with hypoechogenic background and normoechogenic parenchyma, in 30.2%-diffuse thyroiditis with irregular background, in 18.9% nodular variant with normoechogenic background, in 11.7%-micronodulations and in 3.9%-diffuse hypoechogenic background. Eight cases of PTC were diagnosed in nodular variant of AIT with normoechogenic irregular background. Patients with AIT and nodular variant with normoechogenic irregular background of the thyroid gland on US scans are in the risk group of developing PTC and should be followed up with regular neck US assessment.

Faraday polarization fluctuations of satellite beacon signals

NASA Technical Reports Server (NTRS)

Lee, M. C.; Klobuchar, J. A.

1988-01-01

The anisotropic effects of random density irregularities in causing Faraday polarization fluctuations of VHF radio signals are examined, taking both rod-like and sheet-like irregularities into consideration. It is found that the variance of Faraday polarization fluctuations depends on the ratio of perpendicular to parallel correlation lengths. The anisotropic effect of rod-like ionospheric irregularities are shown to be most appreciable for longitudinal propagation. The anisotropic effect of sheet-like ionospheric irregularities, however, is not strongly dependent on the radio propagation angle. During transionospheric propagation at large angles with respect to the geomagnetic field, sheet-like irregularities may cause greater Faraday polarization fluctuations than rod-like irregularities.

Equatorial Density Irregularity Structures at Intermediate Scales and Their Temporal Evolution

NASA Technical Reports Server (NTRS)

Kil, Hyosub; Heelis, R. A.

1998-01-01

We examine high resolution measurements of ion density in the equatorial ionosphere from the AE-E satellite during the years 1977-1981. Structure over spatial scales from 18 km to 200 m is characterized by the spectrum of irregularities at larger and smaller scales and at altitudes above 350 km and below 300 km. In the low-altitude region, only small amplitude large-scale (lambda greater than 5 km) density modulations are often observed, and thus the power spectrum of these density structures exhibits a steep spectral slope at kilometer scales. In the high-altitude region, sinusoidal density fluctuations, characterized by enhanced power near 1-km scale, are frequently observed during 2000-0200 LT. However, such fluctuations are confined to regions at the edges of larger bubble structures where the average background density is high. Small amplitude irregularity structures, observed at early local time hours, grow rapidly to high-intensity structures in about 90 min. Fully developed structures, which are observed at late local time hours, decay very slowly producing only-small differences in spectral characteristics even 4 hours later. The local time evolution of irregularity structure is investigated by using average statistics for low-(1% less than sigma less than 5%) and high-intensity (sigma greater than 10%) structures. At lower altitudes, little chance in the spectral slope is seen as a function of local time, while at higher attitudes the growth and maintenance of structures near 1 km scales dramatically affects the spectral slope.

The growth and decay of equatorial backscatter plumes

NASA Astrophysics Data System (ADS)

Tsunoda, R. T.

1980-02-01

During the past three years, a series of rocket experiments from the Kwajalein Atoll, Marshall Islands, were conducted to investigate the character of intense, scintillation-producing irregularities that occur in the nighttime equatorial ionosphere. Because the source mechanism of equatorial irregularities, believed to be the Rayleigh-Taylor instability, is analogous to that which generates plasma-density striations in a nuclear-induced environment, there is considerable interest in the underlying physics that controls the characteristics of these irregularities. A primary objective of ALTAIR investigations of equatorial irregularities is to seek an understanding of the underlying physics by establishing the relationship between meter-scale irregularities (detected by ALTAIR), and the large-scale plasma-density depletions (or 'bubbles') that contain the kilometer-scale, scintillation-producing irregularities. We describe the time evolution of backscatter 'plumes' produced by one meter equatorial field-aligned irregularities. Using ALTAIR, a fully steerable backscatter radar, to repeatedly map selected plumes, we characterize the dynamic behavior of plumes in terms of growth and a decay phase. Most of the observed characteristics are found to be consistent with equatorial-irregularity generation predicted by current theories of Rayleigh-Taylor and gradient-drift instabilities. However, other characteristics have been found that suggest key roles played by the eastward neutral wind and by altitude-modulation of the bottomside F layer in establishing the initial conditions for plume growth.

Atmospheric pressure, density, temperature and wind variations between 50 and 200 km

NASA Technical Reports Server (NTRS)

Justus, C. G.; Woodrum, A.

1972-01-01

Data on atmospheric pressure, density, temperature and winds between 50 and 200 km were collected from sources including Meteorological Rocket Network data, ROBIN falling sphere data, grenade release and pitot tube data, meteor winds, chemical release winds, satellite data, and others. These data were analyzed by a daily difference method and results on the distribution statistics, magnitude, and spatial structure of the irregular atmospheric variations are presented. Time structures of the irregular variations were determined by the analysis of residuals from harmonic analysis of time series data. The observed height variations of irregular winds and densities are found to be in accord with a theoretical relation between these two quantities. The latitude variations (at 50 - 60 km height) show an increasing trend with latitude. A possible explanation of the unusually large irregular wind magnitudes of the White Sands MRN data is given in terms of mountain wave generation by the Sierra Nevada range about 1000 km west of White Sands. An analytical method is developed which, based on an analogy of the irregular motion field with axisymmetric turbulence, allows measured or model correlation or structure functions to be used to evaluate the effective frequency spectra of scalar and vector quantities of a spacecraft moving at any speed and at any trajectory elevation angle.

Verification of echo amplitude envelope analysis method in skin tissues for quantitative follow-up of healing ulcers

NASA Astrophysics Data System (ADS)

Omura, Masaaki; Yoshida, Kenji; Akita, Shinsuke; Yamaguchi, Tadashi

2018-07-01

We aim to develop an ultrasonic tissue characterization method for the follow-up of healing ulcers by diagnosing collagen fibers properties. In this paper, we demonstrated a computer simulation with simulation phantoms reflecting irregularly distributed collagen fibers to evaluate the relationship between physical properties, such as number density and periodicity, and the estimated characteristics of the echo amplitude envelope using the homodyned-K distribution. Moreover, the consistency between echo signal characteristics and the structures of ex vivo human tissues was verified from the measured data of normal skin and nonhealed ulcers. In the simulation study, speckle or coherent signal characteristics are identified as periodically or uniformly distributed collagen fibers with high number density and high periodicity. This result shows the effectiveness of the analysis using the homodyned-K distribution for tissues with complicated structures. Normal skin analysis results are characterized as including speckle or low-coherence signal components, and a nonhealed ulcer is different from normal skin with respect to the physical properties of collagen fibers.

Spatial irregularities in Jupiter's upper ionosphere observed by Voyager radio occultations

NASA Technical Reports Server (NTRS)

Hinson, D. P.; Tyler, G. L.

1982-01-01

Radio scintillations (at 3.6 and 13 cm) produced by scattering from ionospheric irregularities during the Voyager occultations are interpreted using a weak-scattering theory. Least squares solutions for ionospheric parameters derived from the observed fluctuation spectra yield estimates of (1) the axial ratio, (2) angular orientation of the anisotropic irregularities, (3) the power law exponent of the spatial spectrum of irregularities, and (4) the magnitude of the spatial variations in electron density. It is shown that the measured angular orientation of the anisotropic irregularities indicates magnetic field direction and may provide a basis for refining Jovian magnetic field models.

Fertility biomarkers to estimate metabolic risks in women with polycystic ovary syndrome.

PubMed

Detti, Laura; Jeffries-Boyd, Heather E; Williams, Lucy J; Diamond, Michael P; Uhlmann, Rebecca A

2015-12-01

We sought to evaluate the relationship between the polycystic ovary syndrome (PCOS)-defining characteristics and the risk of developing metabolic complications in women presenting with complaints of infertility and/or menstrual irregularities and subsequently diagnosed with PCOS. This was a cross-sectional study. Women presenting with complaints of infertility and/or irregular menses and diagnosed with PCOS by the Rotterdam criteria, underwent endocrine, metabolic, and ultrasound assessment in the early follicular phase. Reproductive and metabolic parameters were included in regression analysis models with the PCOS-defining characteristics; ROC curves were calculated for the significant predictors. Three hundred and seventy-four women with PCOS were included in our study. Oligo-anovulation, menstrual irregularities, and hirsutism were not predictive of any of the variables. Ovarian volume, follicle count, and biochemical hyperandrogenism were predictors for hormonal, metabolic, and endometrial complications. The relationships were independent of age and body mass index. ROC curves identified lower cut-off values of the PCOS-defining characteristics to predict patients' risks of hyperinsulinemia, dyslipidemia, and glucose intolerance. Adverse metabolic effects of PCOS are already present in women at the time they present complaining of infertility and/or irregular menses. Hyperandrogenism and ultrasound can assist in predicting the patients' concomitant metabolic abnormalities and can aid physicians in tailoring counseling for effective preventive strategies.

Obtaining source current density related to irregularly structured electromagnetic target field inside human body using hybrid inverse/FDTD method.

PubMed

Han, Jijun; Yang, Deqiang; Sun, Houjun; Xin, Sherman Xuegang

2017-01-01

Inverse method is inherently suitable for calculating the distribution of source current density related with an irregularly structured electromagnetic target field. However, the present form of inverse method cannot calculate complex field-tissue interactions. A novel hybrid inverse/finite-difference time domain (FDTD) method that can calculate the complex field-tissue interactions for the inverse design of source current density related with an irregularly structured electromagnetic target field is proposed. A Huygens' equivalent surface is established as a bridge to combine the inverse and FDTD method. Distribution of the radiofrequency (RF) magnetic field on the Huygens' equivalent surface is obtained using the FDTD method by considering the complex field-tissue interactions within the human body model. The obtained magnetic field distributed on the Huygens' equivalent surface is regarded as the next target. The current density on the designated source surface is derived using the inverse method. The homogeneity of target magnetic field and specific energy absorption rate are calculated to verify the proposed method.

Bispectral analysis of equatorial spread F density irregularities

NASA Technical Reports Server (NTRS)

Labelle, J.; Lund, E. J.

1992-01-01

Bispectral analysis has been applied to density irregularities at frequencies 5-30 Hz observed with a sounding rocket launched from Peru in March 1983. Unlike the power spectrum, the bispectrum contains statistical information about the phase relations between the Fourier components which make up the waveform. In the case of spread F data from 475 km the 5-30 Hz portion of the spectrum displays overall enhanced bicoherence relative to that of the background instrumental noise and to that expected due to statistical considerations, implying that the observed f exp -2.5 power law spectrum has a significant non-Gaussian component. This is consistent with previous qualitative analyses. The bicoherence has also been calculated for simulated equatorial spread F density irregularities in approximately the same wavelength regime, and the resulting bispectrum has some features in common with that of the rocket data. The implications of this analysis for equatorial spread F are discussed, and some future investigations are suggested.

Plasma density irregularities and Total Electron Content gradients over Europe

NASA Astrophysics Data System (ADS)

Zakharenkova, I.; Kotulak, K.; Cherniak, I.; Krankowski, A.; Froń, A.

2017-12-01

Perturbations of the ionospheric plasma density are crucial from the scientific and application points of view, as they can severe affect radio signals used in the Global Navigation Satellite Systems (GNSS) and low frequency radio astronomy. For several decades the ionospheric irregularities have been extensively studied by different techniques, including ground-based GNSS observations. Spatial distribution of ionospheric disturbances can be specified by horizontal gradients of the ionospheric density (total electron content, TEC). Another, widely used tool in irregularities monitoring is the rate of TEC index (ROTI). Recently, the Northern Hemisphere ROTI product has been implemented to the International GNSS Service (IGS) and available for community. In this study, we present climatology of the spatial TEC gradients occurred over European region at high to middle latitudes. We developed the TEC gradient maps based on the high-resolution (0.5 degree in latitude and longitude) regional TEC maps covering Europe. The obtained climatological characteristics of the spatial TEC gradients are superimposed and analyzed with the global and regional ROTI product in order to reveal development of highly intense plasma irregularities occurred at high and middle latitudes. During geomagnetic storm the complex of physical processes at auroal zone leads to development of intnse ionospheric irregularities and travelling ionospheric disturbances (TIDs). We presents results of the geomagnetic storm analysis including the 2013 and 2015 St. Patrick's Day geomagnetic storms.

Accurate bulk density determination of irregularly shaped translucent and opaque aerogels

NASA Astrophysics Data System (ADS)

Petkov, M. P.; Jones, S. M.

2016-05-01

We present a volumetric method for accurate determination of bulk density of aerogels, calculated from extrapolated weight of the dry pure solid and volume estimates based on the Archimedes' principle of volume displacement, using packed 100 μm-sized monodispersed glass spheres as a "quasi-fluid" media. Hard particle packing theory is invoked to demonstrate the reproducibility of the apparent density of the quasi-fluid. Accuracy rivaling that of the refractive index method is demonstrated for both translucent and opaque aerogels with different absorptive properties, as well as for aerogels with regular and irregular shapes.

Scintillations associated with bottomside sinusoidal irregularities in the equatorial F region

NASA Technical Reports Server (NTRS)

Basu, S.; Basu, S.; Valladares, C. E.; Dasgupta, A.; Whitney, H. E.

1986-01-01

Multisatellite scintillation observations and spaced receiver drift measurements are presented for a category of equatorial F region plasma irregularities characterized by nearly sinusoidal waveforms in the ion number density. The observations were made at Huancayo, Peru, and the measurements at Ancon, Peru, associated with irregularities observed by the Atmospheric-Explorer-E satellite on a few nights in December 1979. Utilizing ray paths to various geostationary satellites, it was found that the irregularities grow and decay almost simultaneously in long-lived patches extending at least 1000 km in the east-west direction.

Evaluation of irregular menses in perimenarcheal girls: a pilot study.

PubMed

Browner-Elhanan, Karen J; Epstein, Jonathan; Alderman, Elizabeth M

2003-12-01

Acyclic vaginal bleeding in girls within three years of menarche is most commonly attributed to an immature hypothalamic-pituitary-ovarian axis. Assuming this diagnosis may preclude the practitioner from performing more definitive studies and thereby diagnosing other, treatable causes of menstrual irregularities. A retrospective chart review of 178 girls presenting to an inner-city hospital-based adolescent clinic within three years of menarche was performed. Personal and family medical and menarcheal history was assessed, and findings on physical and laboratory examination performed were evaluated. Of the 178 girls still perimenarcheal at presentation, 47 were the focus of this study. Of these, 39 had no significant findings on physical examination, while 3 had signs of functional ovarian hyperandrogenism (FOH) including obesity, hirsutism, and moderate acne with corresponding LH/FSH ratios>3, although pelvic ultrasound examination revealed normal ovaries. Four of the 39 patients with normal physical exams had LH/FSH testing done, and 1 of the 4 had an abnormal LH/FSH ratio, indicating possible FOH. Two of the 47 patients were pregnant. Other laboratory abnormalities included microcytic, hypochromic anemia in patients, and an elevated Erythrocyte Sedimentation Rate in a patient later diagnosed with a rheumatologic disorder. Those perimenarcheal girls presenting with irregular menses and findings including obesity, acne, or pallor, were likely to have treatable causes of menstrual irregularities. In one of the four girls with a normal physical examination, hormonal testing indicated possible FOH, thus suggesting that hormonal evaluation of perimenarcheal girls with menstrual irregularities may be justified, as it may reveal previously unsuspected pathology.

Exploring Properties of HI Clouds in Dwarf Irregular Galaxies

NASA Astrophysics Data System (ADS)

Berger, Clara; Hunter, Deidre Ann

2018-01-01

Dwarf Irregular galaxies form stars and maintain exponential stellar disks at extremely low gas densities. One proposed method of maintaining such regular outer disks is scattering stars off of HI clouds. In order to understand the processes present in dwarf irregular stellar disks, we present a survey of atomic hydrogen clouds in and around a subset of representative galaxies from the LITTLE THINGS survey. We apply a cloud identification program to the 21 cm HI line emission cubes and extract masses, radii, surface densities, and distances from the center of the galaxy in the plane of the galaxy of each cloud. Our data show a wide range of clouds characterized by low surface densities but varied in mass and size. The number of clouds found and the mass of the most massive cloud show no correlation to integrated star forming rates or luminosity in these galaxies. However, they will be used as input for models of stars scattering off of HI clouds to better understand the regular stellar disks in dwarf Irregular galaxies.We acknowledge support from the National Science Foundation grant AST-1461200 to Northern Arizona University for Research Experiences for Undergraduates summer internships.

Hyperthyroidism

MedlinePlus

... and irregular heartbeat Frequent bowel movements or diarrhea Weight loss Goiter, which is an enlarged thyroid that may cause the neck to look swollen To diagnose hyperthyroidism, your doctor will do a physical exam, look ...

Detection of the plasma density irregularities in the topside ionosphere with GPS measurements onboard Swarm satellites

NASA Astrophysics Data System (ADS)

Zakharenkova, Irina; Cherniak, Iurii

2016-07-01

We present new results on the detection of the topside ionospheric irregularities/plasma bubbles using GPS measurements from Precise Orbit Determination (POD) GPS antenna onboard Low Earth Orbit (LEO) satellites. For this purpose we analyze the GPS measurements onboard the ESA's constellation mission Swarm, consisted of three identical satellites with orbit altitude of 450-550 km. We demonstrate that LEO GPS can be an effective tool for monitoring the occurrence of the topside ionospheric irregularities and may essentially contribute to the multi-instrumental analysis of the ground-based and in situ data. In the present study we analyze the occurrence and global distribution of the equatorial ionospheric irregularities during post-sunset period. To support our observations and conclusions, we involve into our analysis in situ plasma density provided by Swarm constellation. Joint analysis of the Swarm GPS and in situ measurements allows us to estimate the occurrence rate of the topside ionospheric irregularities during 2014-2015. The obtained results demonstrate a high degree of similarities in the occurrence pattern of the seasonal and longitudinal distribution of the topside ionospheric irregularities derived on both types of the satellite observations. This work was partially funded by RFBR according to the research project No.16-05-01077 a.

Experimental studies of ionospheric irregularities and related plasma processes

NASA Technical Reports Server (NTRS)

Baker, Kay D.

1992-01-01

Utah State University (USU) continued its program of measuring and interpreting electron density and its variations in a variety of ionospheric conditions with the Experimental Studies of Ionospheric Irregularities and Related Plasma Processes program. The program represented a nearly ten year effort to provide key measurements of electron density and its fluctuations using sounding rockets. The program also involved the joint interpretation of the results in terms of ionospheric processes. A complete campaign summary and a brief description of the major rocket campaigns are also included.

Reverse flow events and small-scale effects in the cusp ionosphere

NASA Astrophysics Data System (ADS)

Spicher, A.; Ilyasov, A. A.; Miloch, W. J.; Chernyshov, A. A.; Clausen, L. B. N.; Moen, J. I.; Abe, T.; Saito, Y.

2016-10-01

We report in situ measurements of plasma irregularities associated with a reverse flow event (RFE) in the cusp F region ionosphere. The Investigation of Cusp Irregularities 3 (ICI-3) sounding rocket, while flying through a RFE, encountered several regions with density irregularities down to meter scales. We address in detail the region with the most intense small-scale fluctuations in both the density and in the AC electric field, which were observed on the equatorward edge of a flow shear, and coincided with a double-humped jet of fast flow. Due to its long-wavelength and low-frequency character, the Kelvin-Helmholtz instability (KHI) alone cannot be the source of the observed irregularities. Using ICI-3 data as inputs, we perform a numerical stability analysis of the inhomogeneous energy-density-driven instability (IEDDI) and demonstrate that it can excite electrostatic ion cyclotron waves in a wide range of wave numbers and frequencies for the electric field configuration observed in that region, which can give rise to the observed small-scale turbulence. The IEDDI can seed as a secondary process on steepened vortices created by a primary KHI. Such an interplay between macroprocesses and microprocesses could be an important mechanism for ion heating in relation to RFEs.

Malaria burden in irregular migrants returning to Sri Lanka from human smuggling operations in West Africa and implications for a country reaching malaria elimination.

PubMed

Wickramage, K; Galappaththy, G N L

2013-05-01

The number of malaria cases among irregular migrants returning to Sri Lanka has not been investigated. In the first 6 months of 2012 we screened 287 irregular migrants returning from seven West African nations to Sri Lanka for malaria to ascertain the risk of infection during migration. Four men were diagnosed as having malaria: three with Plasmodium falciparum had travelled to Togo and one with P. vivax had travelled to Guinea. The risk of contracting malaria was 14 cases per 1000. Facilitating a safe return with selective screening for at-risk inbound migrants flows is desirable as Sri Lanka advances towards its goal of malaria elimination.

Global Distribution of Density Irregularities in the Equatorial Ionosphere

NASA Technical Reports Server (NTRS)

Kil, Hyosub; Heelis, R. A.

1998-01-01

We analyzed measurements of ion number density made by the retarding potential analyzer aboard the Atmosphere Explorer-E (AE-E) satellite, which was in an approximately circular orbit at an altitude near 300 km in 1977 and later at an altitude near 400 km. Large-scale (greater than 60 km) density measurements in the high-altitude regions show large depletions of bubble-like structures which are confined to narrow local time longitude, and magnetic latitude ranges, while those in the low-altitude regions show relatively small depletions which are broadly distributed,in space. For this reason we considered the altitude regions below 300 km and above 350 km and investigated the global distribution of irregularities using the rms deviation delta N/N over a path length of 18 km as an indicator of overall irregularity intensity. Seasonal variations of irregularity occurrence probability are significant in the Pacific regions, while the occurrence probability is always high in die Atlantic-African regions and is always low in die Indian regions. We find that the high occurrence probability in the Pacific regions is associated with isolated bubble structures, while that near 0 deg longitude is produced by large depictions with bubble structures which are superimposed on a large-scale wave-like background. Considerations of longitude variations due to seeding mechanisms and due to F region winds and drifts are necessary to adequately explain the observations at low and high altitudes. Seeding effects are most obvious near 0 deg longitude, while the most easily observed effect of the F region is the suppression of irregularity growth by interhemispheric neutral winds.

Medical and surgical treatment of idiopathic granulomatous lobular mastitis: a benign inflammatory disease mimicking invasive carcinoma.

PubMed

Gurleyik, Gunay; Aktekin, Ali; Aker, Fugen; Karagulle, Hikmet; Saglamc, Abdullah

2012-03-01

Idiopathic granulomatous lobular mastitis (IGLM) is a rare chronic inflammatory disease of the breast with obscure etiology that mimics invasive carcinoma both clinically and radiologically. The treatment of IGLM remains controversial. The aim of proper management is to use a combination of medical and surgical treatment of this benign condition to achieve a good cosmetic result and low recurrence rate. A retrospective analysis of 19 patients with IGLM is performed based on the findings of clinical, radiological, and pathological examinations. The results of two treatments are presented: medical treatment with oral corticosteroids, and consecutive surgical excision after a follow-up period of 20 months (range, 6-75 months). The majority of patients treated in this paper were young (mean, 34 years) parous women with a history of hormonal medication use. The main clinical finding is large, irregular, and painful mass. Hypoechoic lobulated, irregular tubular or oval shaped masses had been imaged by ultrasound. Mammographic findings were an ill-defined mass, enlarged axillary lymph nodes, asymmetric density, and architectural distortion. Diagnoses of IGLM had been established by cytological or histological examination. Symptoms subside and inflammatory changes regressed with medical treatment. The remaining lesions were excised by consecutive breast conserving surgery. The disease recurred in one patient during the follow-up period. IGLM is an inflammatory breast disease found in young women who present with a large painful irregular mass, which mimics carcinoma, as a physical change. Breast imaging modalities are not helpful to differentiate IGLM from invasive cancer. The correct diagnosis is established by cytological or histological examination. Medical treatment with corticosteroids provides significant regression of the inflammatory disease, allowing more conservative surgery. Consecutive surgical excision of the remaining lesions with good cosmetic results provides definitive treatment and reduces the risk of recurrence.

Atrial Fibrillation in Eight New World Camelids.

PubMed

Bozorgmanesh, R; Magdesian, K G; Estell, K E; Stern, J A; Swain, E A; Griffiths, L G

2016-01-01

There is limited information on the incidence of clinical signs, concurrent illness and treatment options for atrial fibrillation (AF) in New World Camelids (NWC). Describe clinical signs and outcome of AF in NWC. Eight New World Camelids admitted with AF. A retrospective observational study of camelids diagnosed with AF based on characteristic findings on electrocardiogram (ECG). All animals had an irregularly irregular heart rhythm detected on physical examination and 4 cases had obtunded mentation on admission. Three camelids were diagnosed with AF secondary to oleander intoxication, 3 animals had underlying cardiovascular disease, 1 was diagnosed with lone AF and 1 had AF diagnosed on examination for a urethral obstruction. Five of eight animals survived to discharge and nonsurvivors consisted of animals which died or were euthanized as a result of cardiovascular disease (2/8) or extra-cardiac disease unrelated to the AF (1/8). Atrial fibrillation occurs in NWC in association with cardiovascular disease, extra-cardiac disease or as lone AF. Amiodarone and transthoracic cardioversion were attempted in one llama with lone AF, but were unsuccessful. Atrial fibrillation was recorded in 0.1% of admissions. Copyright © 2015 The Authors. Journal of Veterinary Internal Medicine published by Wiley Periodicals, Inc. on behalf of the American College of Veterinary Internal Medicine.

Multi-instrumental Study of Storm-induced Ionospheric Irregularities at Midlatitudes

NASA Astrophysics Data System (ADS)

Cherniak, I.; Zakharenkova, I.; Sokolovskiy, S. V.

2017-12-01

We present multi-instrumental analysis of the unusually intense plasma density irregularities occurred over European midlatitudes during geomagnetic storm of 22-23 June 2015. We combine GPS/GLONASS observations derived from the dense ground-based networks ( 1500 stations) with in situ plasma density onboard Swarm and DMSP satellites and COSMIC Radio Occultation (RO) ionospheric electron density profiles. During this geomagnetic storm, the strong ionospheric irregularities of auroral origin were registered over the Northern Europe sub-auroral and midlatitudes. Meanwhile, another kind of ionospheric irregularities of equatorial origin reached European midlatitudes from the south. The prompt penetration electric fields caused the occurrence of plasma bite-outs in the post-sunset sector over the Western Africa low latitudes and extension of the large-scale plasma bubbles toward Europe. Using GPS/GLONASS observations, the plasma bubble signatures were mapped in Europe. They were observed for more than 8 h (20-04 UT) and covered a broad area within 30o-40o N and 20o W-10o E. In this region, the steep plasma gradients, as large as 5-10 TECU/degree, and numerous embedded deep plasma depletions were developed on the background of high plasma density. For low latitude region, the bite-out signature was recognized in the form of the significantly modified shape of the COSMIC-derived ionospheric electron density profiles. These unique results were confirmed by the in situ density and upward-looking GPS data onboard the Swarm satellites at 500 km altitude, in situ density measured by DMSP and ground-based absolute TEC observations. It was found that close similarity between in situ Ne and Swarm-derived topside vertical TEC suggests that plasma density enhancements and depletions are developed in the topside ionosphere (>500 km). The intensity of plasma gradients at different altitudes was also estimated by COSMIC-based measurements of GPS signal intensity and phase fluctuations as well as by rate of TEC changes on COSMIC-GPS links. Occurrence of the plasma bubbles in Europe affected GNSS measurements over number of reference stations and led to performance degradation of SBAS EGNOS.

Detection of F-region electron density irregularities using incoherent-scatter radar

NASA Astrophysics Data System (ADS)

Gudivada, Krishna Prasad

Incoherent-scatter radar data from Poker Flat, Alaska has been used to determine size distributions of electron density structures in the evening time sector of the auroral zone. At high latitudes ionospheric plasma typically moves east-west with speeds of several hundred meters per second. Density irregularities that rapidly move through the radar beam are therefore observed as time-varying power fluctuations. The new phased array radar used for this study has been operated with several antenna directions with successive pulses transmitted in each direction. It is therefore possible to observe plasma Doppler velocities in multiple directions and determine the vector direction of the plasma motion. This near-simultaneous observation of the plasma velocity in conjunction with the electron density height profile data enable a new technique to determine the scale sizes of electron density fluctuations that move horizontally through the radar beam. The study focuses on the collision-less F-region ionosphere where the plasma drift is approximately constant with altitude. The experimental technique limits the range of scale sizes that may be studied to relatively large-scale sizes (i.e. greater than few tens of km). Results show that during magnetically disturbed conditions (Kp ≥ 4) when westward plasma velocities are relatively high (500-1000 m/s) the scale sizes of irregularities (often called plasma blobs) are in the range of 100-300 km and predominantly originate from the polar cap and are transported over long distances (˜1000 km) due to the long chemical recombination times (30-90 minutes). Some irregularities are caused by local auroral particle precipitation and have been identified with associated electron temperature enhancements. For cases of low magnetic activity (Kp ≤ 1), when the radar is located in a region of low plasma velocities (100-500 m/s) well south of the auroral oval (essentially a mid-latitude type ionosphere), the density distribution is always biased strongly toward small-scale sizes (less than 50 km).

Studies of small scale irregularities in the cusp ionosphere using sounding rockets: recent results

NASA Astrophysics Data System (ADS)

Spicher, A.; Ilyasov, A. A.; Miloch, W. J.; Chernyshov, A. A.; Moen, J.; Clausen, L. B. N.; Saito, Y.

2017-12-01

Plasma irregularities occurring over many scale sizes are common in the ionosphere. Understanding and characterizing the phenomena responsible for these irregularities is not only important from a theoretical point of view, but also in the context of space weather, as the irregularities can disturb HF communication and Global Navigation Satellite Systems signals. Overall, research about the small-scale turbulence has not progressed as fast for polar regions as for the equatorial ones, and for the high latitude ionosphere there is still no agreement nor detailed explanation regarding the formation of irregularities. To investigate plasma structuring at small scales in the cusp ionosphere, we use high resolution measurements from the Investigation of Cusp Irregularities (ICI) sounding rockets, and investigate a region associated with density enhancements and a region characterized by flow shears. Using the ICI-2 electron density data, we give further evidence of the importance of the gradient drift instability for plasma structuring inside the polar cap. In particular, using higher-order statistics, we provide new insights into the nature of the resulting plasma structures and show that they are characterized by intermittency. Using the ICI-3 data, we show that the entire region associated with a reversed flow event (RFE), with the presence of meter-scale irregularities, several flow shears and particle precipitation, is highly structured. By performing a numerical stability analysis, we show that the inhomogeneous-energy-density-driven instability (IEDDI) may be active in relation to RFEs at the rocket's altitude. In particular, we show that the presence of particle precipitation decreases the growth rates of IEDDI and, using a Local Intermittency Measure, we observe a correlation between IEDDI growth rates and electric field fluctuations over several scales. These findings support the view that large-scale inhomogeneities may provide a background for the development of micro-scale instabilities. Such interplay between macro- and micro-processes might be an important mechanism for the development of small-scale plasma gradients, and as a source for ion heating in the cusp ionosphere.

Electromagnetic Scattering From a Polygonal Thin Metallic Plate Using Quadrilateral Meshing

NASA Technical Reports Server (NTRS)

Deshpande, Manohar D.

2003-01-01

The problem of electromagnetic (EM) scattering from irregularly shaped, thin, metallic flat plates in free space is solved using the electric field integral equation (EFIE) approach in conjunction with the method of moments (MoM) with quadrilateral meshing. An irregularly shaped thin plate is discretized into quadrilateral patches and the unknown electric surface current over the plate is expressed in terms of proper basis functions over these patches. The basis functions for the electric surface current density that satisfy the proper boundary conditions on these quadrilateral patches are derived. The unknown surface current density on these quadrilateral patches is determined by setting up and solving the electric field integral equation by the application of the MoM. From the knowledge of the surface current density, the EM scattering from various irregularly shaped plates is determined and compared with the earlier published results. The novelty in the present approach is the use of quadrilateral patches instead of well known and often used triangular patches. The numerical results obtained using the quadrilateral patches compare favorably with measured results.

Bottomside sinusoidal irregularities in the equatorial F region

NASA Technical Reports Server (NTRS)

Valladares, C. E.; Hanson, W. B.; Mcclure, J. P.; Cragin, B. L.

1983-01-01

By using the Ogo 6 satellite, McClure and Hanson (1973) have discovered sinusoidal irregularities in the equatorial F region ion number density. In the present investigation, a description is provided of the properties of a distinct category of sinusoidal irregularities found in equatorial data from the AE-C and AE-E satellites. The observed scale sizes vary from about 300 m to 3 km in the direction perpendicular to B, overlapping with and extending the range observed by using Ogo 6. Attention is given to low and high resolution data, a comparison with Huancayo ionograms, the confinement of 'bottomside sinusoidal' (BSS) irregularities essentially to the bottomside of the F layer, spectral characteristics, and BSS, scintillation, and ionosonde observations.

Ionospheric irregularity characteristics from quasiperiodic structure in the radio wave scintillation

NASA Astrophysics Data System (ADS)

Chen, K. Y.; Su, S. Y.; Liu, C. H.; Basu, S.

2005-06-01

Quasiperiodic (QP) diffraction pattern in scintillation patches has been known to highly correlate with the edge structures of a plasma bubble (Franke et al., 1984). A new time-frequency analysis method of Hilbert-Huang transform (HHT) has been applied to analyze the scintillation data taken at Ascension Island to understand the characteristics of corresponding ionosphere irregularities. The HHT method enables us to extract the quasiperiodic diffraction signals embedded inside the scintillation data and to obtain the characteristics of such diffraction signals. The cross correlation of the two sets of diffraction signals received by two stations at each end of Ascension Island indicates that the density irregularity pattern that causes the diffraction pattern should have an eastward drift velocity of ˜130 m/s. The HHT analysis of the instantaneous frequency in the QP diffraction patterns also reveals some frequency shifts in their peak frequencies. For the QP diffraction pattern caused by the leading edge of the large density gradient at the east wall of a structured bubble, an ascending note in the peak frequency is observed, and for the trailing edge a descending note is observed. The linear change in the transient of the peak frequency in the QP diffraction pattern is consistent with the theory and the simulation result of Franke et al. Estimate of the slope in the transient frequency provides us the information that allows us to identify the locations of plasma walls, and the east-west scale of the irregularity can be estimated. In our case we obtain about 24 km in the east-west scale. Furthermore, the height location of density irregularities that cause the diffraction pattern is estimated to be between 310 and 330 km, that is, around the F peak during observation.

Very High-Frequency (VHF) ionospheric scintillation fading measurements at Lima, Peru

NASA Technical Reports Server (NTRS)

Blank, H. A.; Golden, T. S.

1972-01-01

During the spring equinox of 1970, scintillating signals at VHF (136.4 MHz) were observed at Lima, Peru. The transmission originated from ATS 3 and was observed through a pair of antennas spaced 1200 feet apart on an east-west baseline. The empirical data were digitized, reduced, and analyzed. The results include amplitude probability density and distribution functions, time autocorrelation functions, cross correlation functions for the spaced antennas, and appropriate spectral density functions. Results show estimates of the statistics of the ground diffraction pattern to gain insight into gross ionospheric irregularity size, and irregularity velocity in the antenna planes.

Characterization of Nightside Mid-latitude Irregularities Observed with the Blackstone SuperDARN Radar

NASA Astrophysics Data System (ADS)

Ruohoniemi, J. M.; Ribeiro, A. J.; Baker, J. B.; Greenwald, R. A.; Newell, P. T.

2009-12-01

The new mid-latitude SuperDARN radars at Wallops Island and Blackstone observe strong coherent backscattering on an almost nightly basis from latitudes that appear to be subauroral. One study has demonstrated an excellent correlation with the occurrence of density and temperature gradients within the ionospheric projection of the plasmapause (Greenwald et al., Geophys. Res. Lett. [2006]). We have processed all the data collected with the Blackstone radar since its inception in February 2008 for a characterization of the occurrence and properties of ‘plasmapause’ scatter. We have determined the local time and Kp dependencies of the activity and the relation of the spatial distribution of the irregularities to magnetospheric boundaries and ionospheric density gradients. We establish that the irregularities are a feature of the quiet-time subauroral ionosphere and provide a valuable diagnostic of the electric fields in the inner magnetosphere.

How Do Health Care Providers Diagnose Menstrual Irregularities?

MedlinePlus

... the following: 1 , 2 , 3 , 4 , 5 Medical history Physical examination Blood tests Ultrasound examination Endometrial biopsy—a small sample of the uterus's endometrial lining is taken to be examined under a microscope Hysteroscopy—a diagnostic scope that allows a health ...

Extended applications of track irregularity probabilistic model and vehicle-slab track coupled model on dynamics of railway systems

NASA Astrophysics Data System (ADS)

Xu, Lei; Zhai, Wanming; Gao, Jianmin

2017-11-01

Track irregularities are inevitably in a process of stochastic evolution due to the uncertainty and continuity of wheel-rail interactions. For depicting the dynamic behaviours of vehicle-track coupling system caused by track random irregularities thoroughly, it is a necessity to develop a track irregularity probabilistic model to simulate rail surface irregularities with ergodic properties on amplitudes, wavelengths and probabilities, and to build a three-dimensional vehicle-track coupled model by properly considering the wheel-rail nonlinear contact mechanisms. In the present study, the vehicle-track coupled model is programmed by combining finite element method with wheel-rail coupling model firstly. Then, in light of the capability of power spectral density (PSD) in characterising amplitudes and wavelengths of stationary random signals, a track irregularity probabilistic model is presented to reveal and simulate the whole characteristics of track irregularity PSD. Finally, extended applications from three aspects, that is, extreme analysis, reliability analysis and response relationships between dynamic indices, are conducted to the evaluation and application of the proposed models.

Dynamics of the High-latitude Ionospheric Irregularities During the 2015 St. Patrick's Day Storm

NASA Astrophysics Data System (ADS)

Cherniak, I.; Zakharenkova, I.; Redmon, R. J.; Andrzej, K.

2015-12-01

We presents results on the study of the high-latitude ionospheric irregularities observed in worldwide GPS data during the St. Patrick's Day geomagnetic storm (March 17, 2015). Multi-site GPS observations from more than 2500 ground-based GPS stations were used to analyze the dynamics of the ionospheric irregularities in the Northern and Southern Hemispheres. The most intense ionospheric irregularities lasted for more than 24 hours starting at 07 UT of March 17. This period correlates well with an increase of the auroral Hemispheric Power index. We find hemispheric asymmetries in the intensity and spatial structure of the ionospheric irregularities. Over North America the ionospheric irregularities zone expanded equatorward below ~45°N geographic latitude. Additionally, the strong mid and high latitude GPS phase irregularities in the auroral oval were found to be related to the formation of storm enhanced density, polar tongues of ionization and deepening of the main ionospheric trough through upper atmosphere ionization by energetic particle precipitations. Significant increases in the intensity of the irregularities within the polar cap region of both hemispheres were associated with the formation and evolution of the SED/TOI structures and polar patches.

Utilizing a Segmented Fuel Cell to Study the Effects of Electrode Coating Irregularities on PEM Fuel Cell Initial Performance

DOE PAGES

Phillips, Adam; Ulsh, Michael; Porter, Jason; ...

2017-04-27

An understanding of the impact of coating irregularities on beginning of life polymer electrolyte fuel cell (PEMFC) performance is essential to develop and establish manufacturing tolerances for its components. Coating irregularities occurring in the fuel cell electrode can either possess acceptable process variations or potentially harmful defects. A segmented fuel cell (SFC) is employed to understand how 100% catalyst reduction irregularities ranging from 0.125 to 1 cm 2 in the cathode electrode of a 50 cm 2 sized cell impact spatial and total cell performance at dry and wet humidification conditions. Here, by analyzing the data in a differential formatmore » the local performance effects of irregularity sizes down to 0.25 cm 2 were detected in the current distribution of the cell. Slight total cell performance impacts, due to irregularity sizes of 0.5 and 1 cm 2, were observed under dry operation and high current densities.« less

Utilizing a Segmented Fuel Cell to Study the Effects of Electrode Coating Irregularities on PEM Fuel Cell Initial Performance

DOE Office of Scientific and Technical Information (OSTI.GOV)

Phillips, Adam; Ulsh, Michael; Porter, Jason

An understanding of the impact of coating irregularities on beginning of life polymer electrolyte fuel cell (PEMFC) performance is essential to develop and establish manufacturing tolerances for its components. Coating irregularities occurring in the fuel cell electrode can either possess acceptable process variations or potentially harmful defects. A segmented fuel cell (SFC) is employed to understand how 100% catalyst reduction irregularities ranging from 0.125 to 1 cm 2 in the cathode electrode of a 50 cm 2 sized cell impact spatial and total cell performance at dry and wet humidification conditions. Here, by analyzing the data in a differential formatmore » the local performance effects of irregularity sizes down to 0.25 cm 2 were detected in the current distribution of the cell. Slight total cell performance impacts, due to irregularity sizes of 0.5 and 1 cm 2, were observed under dry operation and high current densities.« less

Mesospheric plasma irregularities caused by the missile destruction on 9 December 2009

NASA Astrophysics Data System (ADS)

Kozlovsky, Alexander; Shalimov, Sergey; Lester, Mark

2017-06-01

On 9 December 2009 at about 07 UT a solid propellant 36.8 t ballistic rocket was self-destroyed at an altitude of 170-260 km, at a distance of about 500 km to the east of Sodankylä Geophysical Observatory (SGO, 67°22'N, 26°38'E, Finland). After 2-3 h the SGO meteor radar (operating at a frequency 36.9 MHz) received unusual echoes, which indicate turbulence of ionospheric plasma (irregularities of electron density) with a temporal scale on the order of 0.1 s and a spatial scale of a few to tens of meters. The turbulence occurred at a height of about 80 km and was localized in several areas of about 60 km in horizontal scale. Line-of-sight velocity of the irregularities was up to a few tens of meters per second toward the radar. The event occurred in the winter high-latitude mesosphere during extremely low solar and geomagnetic activity. Aerosol particles caused by the missile explosion played a key role in producing the electron density irregularities. As a possible explanation, we suggest that sedimented by gravity and, hence, moving with respect to the air, charged aerosol particles (presumably composed of aluminum oxide) might produce meter-scale irregularities (electrostatic waves) via dissipative instability, which is a mechanism analogous to that of the resistive beam-plasma instability.

Disruptive patterns of eating behaviors and associated lifestyles in males with ADHD.

PubMed

Ptacek, Radek; Kuzelova, Hana; Stefano, George B; Raboch, Jiří; Sadkova, Tereza; Goetz, Michal; Kream, Richard M

2014-04-14

Attention deficit hyperactivity disorder (ADHD) is a neurological/behavioral disorder characterized by inattention or hyperactivity and impulsivity, or combined symptomatology. Children with ADHD are predisposed to irregular and/or impulsive eating patterns often leading to compromised physical condition. The goal of the present study was to statistically evaluate parental scoring of patterned eating behaviors and associated lifestyles within a cohort of 100 boys diagnosed with ADHD in comparison to age-matched male controls. The study population consisted of 100 boys aged 6-10 years diagnosed with mixed type ADHD by DSM-IV criteria and 100 aged-matched healthy male control subjects. Patterns of eating behaviors and associated lifestyles were scored by structured parental interviews using a nominal rating scale. Interview scores indicated statistically significant differences in patterned eating behaviors in subjects with ADHD in comparison to healthy controls. Notably, subjects diagnosed with ADHD exhibited markedly diminished adherence to a traditional breakfast, lunch, and dinner schedule, which was linked to a significantly higher frequency (>5/day) of irregular eating times. In the ADHD cohort, disruptive patterns of eating behaviors were associated with diminished nutritional value of ingested food (expressed as lowered content of fruits and vegetables) and increased consumption of sweetened beverages. Disruptive patterns of eating behaviors, metabolically unfavorable nutritional status, and diminished physical activities of male children diagnosed with ADHD are linked to compromised growth and development and appearance of metabolic diseases in adulthood.

Study of a coincident observation between the ROCSAT-1 density irregularity and Ascension Island scintillation

NASA Astrophysics Data System (ADS)

Liu, Y. H.; Chao, C. K.; Su, S.-Y.; Liu, C. H.

2012-10-01

A coincident observation that occurred on 24 March 2000 between the irregularity structure measured by ROCSAT-1 and the scintillation experiment at the Ascension Island has been studied. The study of scintillation statistics is carried out first, and the results show that the Nakagami distribution can portray the normalized intensity of the L-band scintillation at various S4 values, up to S4 equal to 1.4. Moreover, the departure of frequency dependence on S4 predicted by the weak scintillation is noticed due to multiple forward scattering effects. The coincident feature between the characteristics of irregularity structure and the scintillation variation are then studied. The causal relationship between the fluctuation of ion density and the scintillation variation is obtained. A numerical simulation using the parabolic wave equation has been carried out with the ROCSAT-1 data in space to compare with the ground scintillation observation. The results show the reasonable scintillation level at the coincident time to indicate a direct relationship between the irregularity structure and the scintillation in both temporal and amplitudinal variations. Finally, some assumptions and limitations of the simulation model are discussed.

Clinical usefulness of magnifying endoscopy for non-ampullary duodenal tumors.

PubMed

Mizumoto, Takeshi; Sanomura, Yoji; Tanaka, Shinji; Kuroki, Kazutoshi; Kurihara, Mio; Yoshifuku, Yoshikazu; Oka, Shiro; Arihiro, Koji; Shimamoto, Fumio; Chayama, Kazuaki

2017-04-01

Study aims  This study aimed to investigate the clinical usefulness of magnifying endoscopy (ME) for non-ampullary duodenal tumors. Patients and methods  We enrolled 103 consecutive patients with non-ampullary duodenal tumors that were observed by ME with narrow-band imaging (ME-NBI) and had pit pattern analysis before endoscopic resection at Hiroshima University Hospital before December 2014. ME-NBI images were classified as Type B or Type C according to the Hiroshima classification, and pit patterns were classified as regular or irregular. We studied the clinicopathological features and diagnoses with ME-NBI and pit pattern analyses according to the Vienna classification (category 3: 73 patients; category 4: 30 patients). Results  Category 4 lesions were significantly larger than category 3 lesions. According to ME-NBI images, category 4 Type C lesions (83 %) were significantly more common than category 4 Type B lesions (17 %). According to pit pattern analyses, category 4 irregular lesions 4 (77 %) were significantly more common than category 4 regular lesions (23 %). The accuracies of using Type C ME-NBI images and irregular pit patterns to diagnose category 4 lesions were 87 % and 84 %, the sensitivities were 83 % and 77 %, and the specificities were 89 % and 88 %, respectively. There was no significant difference between ME-NBI and pit pattern analyses for diagnosing the histologic grade of non-ampullary duodenal tumors. Conclusion  Our study showed that ME-NBI and pit pattern analysis had equivalent abilities to determine the histologic grade of non-ampullary duodenal tumors. ME-NBI may be more useful because it is a simple, less time-consuming procedure.

Using the androgen excess-PCOS society criteria to diagnose polycystic ovary syndrome and the risk of metabolic syndrome in adolescents.

PubMed

Roe, Andrea Hsu; Prochaska, Erica; Smith, Matthew; Sammel, Mary; Dokras, Anuja

2013-05-01

To use the Androgen Excess-PCOS Society (AE-PCOS) criteria in adolescents to diagnose polycystic ovary syndrome (PCOS) and identify the prevalence of metabolic risk factors. Retrospective chart review of adolescents (>2 years postmenarche) presenting at a specialty clinic from 2008 through 2010 with complete evaluation for PCOS and metabolic risk were reviewed. Metabolic risk in adolescents with PCOS was compared with those with ≤ 1 AE-PCOS criteria. Of the 205 adolescents evaluated, 66% were found to have PCOS based on the AE-PCOS criteria. The most common presenting symptom was menstrual irregularity, followed by acne, hirsutism, and weight gain. Adolescents with PCOS had a significantly higher prevalence of obesity, hypertension, and low level of high-density lipoprotein cholesterol. Subjects with PCOS had ≥ 1 metabolic risk factor compared with the subjects without PCOS (63.6% vs 33.3%, P = .002). More adolescents with PCOS had ≥ 2 abnormal metabolic risk factors excluding body mass index compared with those without PCOS (P < .02). The prevalence of metabolic syndrome (≥ 3 risk factors) was 10.8% in adolescents with PCOS compared with 1.7% in those without PCOS (P < .04). Adolescents diagnosed with PCOS based on the AE-PCOS criteria are at a significantly increased risk of ≥ 1 metabolic abnormality. Our data underscore the need to accurately diagnose PCOS in the adolescent population instead of delaying the diagnosis to adulthood. Further, using similar criteria for the diagnosis of PCOS in adolescents (>2 years postmenarche) and adults will be more convenient for the clinician. Copyright © 2013 Mosby, Inc. All rights reserved.

[Analysis of the diagnosis and treatment of desmoplastic small round cell tumor].

PubMed

Lu, Baojian; Zhang, Wei; Shang, Zhiqun; Sun, Erlin; Nian, Xuewu; Gao, Jingda; Ma, Chengquan; Han, Ruifa

2015-09-01

To explore the clinical diagnostic features and treatment of desmoplastic small round cell tumor (DSRCT), and to improve the understanding and management of this tumor. The clinicopathological data of nine patients treated in our hospital from October 2004 to June 2014 were retrospectively analyzed and a review of the literature was made. The clinical manifestations, pathological characteristics, diagnosis and differential diagnosis, treatment and prognosis of this tumor were summarized and analyzed. Nine patients with DSRCT, 5 males and 4 females, with an average age of 21 years (range 8-56 years) were included in this study. Ultrasound examination revealed irregular low-density mass shadow in the abdominal cavity. CT examination found that 6 cases had abdominal and retroperitoneal multiple solid tumor nodules, uneven density, and visible low density fluid area. Postoperative pathological examination revealed that the tumor cells were small, mostly elliptic, gathered to form clear structure of nests with clear irregular boundaries. The central portion of large tumor nests often showed necrosis. Scattered fibroblasts and large amount of hyalinization of collagen fibers were seen in the interstitial tissue around the nests. Six patients received laparotomy surgery, however, all failed to resect the tumor completely. Three patients received postoperative chemotherapy, i. e. two cases had carboplatin and paclitaxel chemotherapy, and one case of chemotherapy regimen not specified. Two patients had radiation and chemotherapy (no concrete plan was available). Another case was lost to follow-up. Two of the three patients without surgery received chemotherapy with CAP (cyclophosphamide+adriamycin+carboplatin) and total rectal lesions, pelvic and inguinal lymph nodes, ilium metastases radiation therapy. Another one patient received EP regimen (DDP+VP16) which was then changed into a TP chemotherapy alone. Eight of the nine cases died shortly after surgery, and only one patient treated with chemotherapy alone was still alive after 11 months of follow-up. Desmoplastic small round cell tumor is a very rare, special type of soft tissue tumor, with very poor prognosis. This tumor may be preliminarily diagnosed according to the imaging characteristics and detection of tumor markers, however, final diagnosis is made by pathology. Surgery is the priority of treatment, combined with complementary radiation and chemotherapy.

Frequency correlation of probe waves backscattered from small scale ionospheric irregularities generated by high power HF radio waves

NASA Astrophysics Data System (ADS)

Puchkov, V. A.

2016-09-01

Aspect sensitive scattering of multi-frequency probe signals by artificial, magnetic field aligned density irregularities (with transverse size ∼ 1- 10 m) generated in the ionosphere by powerful radio waves is considered. Fluctuations of received signals depending on stochastic properties of the irregularities are calculated. It is shown that in the case of HF probe waves two mechanisms may contribute to the scattered signal fluctuations. The first one is due to the propagation of probe waves in the ionospheric plasma as in a randomly inhomogeneous medium. The second one lies in non-stationary stochastic behavior of irregularities which satisfy the Bragg conditions for the scattering geometry and therefore constitute centers of scattering. In the probe wave frequency band of the order of 10-100 MHz the second mechanism dominates which delivers opportunity to recover some properties of artificial irregularities from received signals. Correlation function of backscattered probe waves with close frequencies is calculated, and it is shown that detailed spatial distribution of irregularities along the scattering vector can be found experimentally from observations of this correlation function.

Construction of a stochastic model of track geometry irregularities and validation through experimental measurements of dynamic loading

NASA Astrophysics Data System (ADS)

Panunzio, Alfonso M.; Puel, G.; Cottereau, R.; Simon, S.; Quost, X.

2017-03-01

This paper describes the construction of a stochastic model of urban railway track geometry irregularities, based on experimental data. The considered irregularities are track gauge, superelevation, horizontal and vertical curvatures. They are modelled as random fields whose statistical properties are extracted from a large set of on-track measurements of the geometry of an urban railway network. About 300-1000 terms are used in the Karhunen-Loève/Polynomial Chaos expansions to represent the random fields with appropriate accuracy. The construction of the random fields is then validated by comparing on-track measurements of the contact forces and numerical dynamics simulations for different operational conditions (train velocity and car load) and horizontal layouts (alignment, curve). The dynamics simulations are performed both with and without randomly generated geometrical irregularities for the track. The power spectrum densities obtained from the dynamics simulations with the model of geometrical irregularities compare extremely well with those obtained from the experimental contact forces. Without irregularities, the spectrum is 10-50 dB too low.

Digital imaging of patterns of dental wear to diagnose bruxism in children.

PubMed

Restrepo, C; Peláez, A; Alvarez, E; Paucar, C; Abad, P

2006-07-01

The aim of this study was to evaluate and compare the area, perimeter, and form (D factor and fractal dimension) of the dental wear among bruxist and nonbruxist children with mixed dentition in order to determine if the dental wear may be used as criteria to diagnose bruxism. The children were 8 to 11 years old and were classified as bruxist or nonbruxist, according to anxiety level and temporomandibular disorders. Dental casts of the upper arch were obtained for the bruxist (n = 24) and the control (n = 29) group. The dental wear was measured in digital format and processed automatically. The complete and pathological dental wear was compared between the two groups, using the Student's t-test and Mann-Whitney test. Statistically significant differences were observed between the two groups, with a higher area, perimeter, and more irregular form of the pathological dental wear among the bruxist group. Regarding complete dental wear, differences were only significant for the D factor (an un-dimensional quantitative parameter which produces a relation between the area and the perimeter of an object). Digital imaging of dental wear may be used as criteria to diagnose bruxism in children with mixed dentition after making an analysis of the area, perimeter, and irregularity of the form of pathological dental wear.

In-situ studies of plasma irregularities in high latitude ionosphere with the ICI-2 sounding rocket within the 4DSpace project

NASA Astrophysics Data System (ADS)

Miloch, Wojciech; Moen, Joran; Spicher, Andres

Ionospheric plasma is often characterized by irregularities, instabilities, and turbulence. Two regions of the ionospheric F-layer are of particular interest: low-latitudes for the equatorial anomaly and electrojet, and high-latitude regions where the most dynamic phenomena occur due to magnetic field lines coupling to the magnetosphere and the solar wind. The spectra of plasma fluctuations in the low-latitude F-layer usually exhibit a power law with a steeper slope at high frequencies [1]. Until recently, there was no clear evidence of the corresponding double slope spectra for plasma fluctuations in the high latitude ionospheric F-layer, and this difference was not well understood. We report the first direct observations of the double slope power spectra for plasma irregularities in the F-layer of the polar ionosphere [2]. The ICI-2 sounding rocket, which intersected enhanced plasma density regions with decameter scale irregularities in the cusp region, measured the electron density with unprecedented high resolution. This allowed for a detailed study of the plasma irregularities down to kinetic scales. Spectral analysis reveals double slope power spectra for regions of enhanced fluctuations associated mainly with density gradients, with the steepening of the spectra occurring close to the oxygen gyro-frequency. The double slope spectra are further supported by the results from the ICI-3 sounding rocket. Double slope spectra were not resolved in previous works presumably due to limited resolution of instruments. The study is a part of the 4DSpace initiative for integrated studies of the ionospheric plasma turbulence with multi-point, multi-scale in-situ studies by sounding rockets and satellites, and numerical and analytical models. A brief overview of the 4DSpace initiative is given. [1] M.C. Kelley, The Earth’s Ionosphere Plasma Physics and Electrodynamics (Elsevier, Amsterdam 2009). [2] A. Spicher, W. J. Miloch, and J. I. Moen, Geophys. Res. Lett. 40, (in press, accepted 13.02.2014).

LISN: A distributed observatory to image and study ionospheric irregularities

NASA Astrophysics Data System (ADS)

Sheehan, R.; Valladares, C. E.

2013-05-01

During nighttime the low-latitude ionosphere commonly develops plasma irregularities and density structures able to disrupt radio wave signals. This interference produces an adverse impact on satellite communication and navigation signals. For example, EM signals originated from satellites can suffer fading as deep as 20 dB even at UHF frequencies. In addition, civil aviation is increasingly dependent upon Global Navigation Satellite Systems and disruption of the navigation capability from ionospheric irregularities poses a clear threat to passengers and crews. To monitor and specify the conditions of the ionosphere over South America, the Low-latitude Ionospheric Sensor Network (LISN) was established as a permanent array of scientific instruments that operate continuously and transmit their observables to a central server in a real-time basis. Presently, the LISN observatory includes 3 different types of instruments: (1) 47 GPS receivers, (2) 5 flux-gate magnetometers and (3) 2 Vertical Incidence Pulsed Ionospheric Radar (VIPIR) ionosondes. In addition to providing a nowcast of the disturbed state of the ionosphere over South America, LISN permits detailed studies of the initiation and development of plasma irregularities. By using data assimilation and tomography techniques, LISN provides continuous estimates of several important geophysical parameters that are indispensable to a program aimed at forecasting the plasma electrodynamics and the formation of density structures in the low-latitude ionosphere.

Rocket measurements of mesospheric ionization irregularities

NASA Technical Reports Server (NTRS)

Stoltzfus, R. B.; Bowhill, S. A.

1985-01-01

The Langmuir probe technique for measurement of electron concentration in the mesosphere is capable of excellent altitude resolution, of order 1 m. Measurements from nine daytime rocket flights carrying an electron density fine structure experiment frequently show small scale ionization structures in the altitude region 70 to 90 km. The irregularities are believed to be the result of turbulent advection of ions and electrons. The fine structure experiment flown by the University of Illinois is described and methods of analyzing the collected data is presented. Theories of homogeneous, isotropic turbulence are reviewed. Power spectra of the measured irregularities are calculated and compared to spectra predicted by turbulence theories.

An investigation of methods for updating ionospheric scintillation models using topside in-situ plasma density measurements

NASA Astrophysics Data System (ADS)

Secan, James A.

1991-05-01

Modern military communication, navigation, and surveillance systems depend on reliable, noise-free transionospheric radio-frequency channels. They can be severely impacted by small-scale electron-density irregularities in the ionosphere, which cause both phase and amplitude scintillation. Basic tools used in planning and mitigation schemes are climatological in nature and thus may greatly over- and under-estimate the effects of scintillation in a given scenario. This report summarizes the results of the first year of a three-year investigation into the methods for updating ionospheric scintillation models using observations of ionospheric plasma-density irregularities measured by DMSP Scintillation Meter (SM) sensor. Results are reported from the analysis of data from a campaign conducted in January 1990 near Tromso, Norway, in which near coincident in-situ plasma-density and transionospheric scintillation measurements were made. Estimates for the level of intensity and phase scintillation on a transionospheric UHF radio link in the early-evening auroral zone were calculated from DMSP SM data and compared to the levels actually observed.

Spheroidization of molybdenum powder by radio frequency thermal plasma

NASA Astrophysics Data System (ADS)

Liu, Xiao-ping; Wang, Kuai-she; Hu, Ping; Chen, Qiang; Volinsky, Alex A.

2015-11-01

To control the morphology and particle size of dense spherical molybdenum powder prepared by radio frequency (RF) plasma from irregular molybdenum powder as a precursor, plasma process parameters were optimized in this paper. The effects of the carrier gas flow rate and molybdenum powder feeding rate on the shape and size of the final products were studied. The molybdenum powder morphology was examined using high-resolution scanning electron microscopy. The powder phases were analyzed by X-ray diffraction. The tap density and apparent density of the molybdenum powder were investigated using a Hall flow meter and a Scott volumeter. The optimal process parameters for the spherical molybdenum powder preparation are 50 g/min powder feeding rate and 0.6 m3/h carrier gas rate. In addition, pure spherical molybdenum powder can be obtained from irregular powder, and the tap density is enhanced after plasma processing. The average size is reduced from 72 to 62 µm, and the tap density is increased from 2.7 to 6.2 g/cm3. Therefore, RF plasma is a promising method for the preparation of high-density and high-purity spherical powders.

Medical and Surgical Treatment of Idiopathic Granulomatous Lobular Mastitis: A Benign Inflammatory Disease Mimicking Invasive Carcinoma

PubMed Central

Aktekin, Ali; Aker, Fugen; Karagulle, Hikmet; Saglamc, Abdullah

2012-01-01

Purpose Idiopathic granulomatous lobular mastitis (IGLM) is a rare chronic inflammatory disease of the breast with obscure etiology that mimics invasive carcinoma both clinically and radiologically. The treatment of IGLM remains controversial. The aim of proper management is to use a combination of medical and surgical treatment of this benign condition to achieve a good cosmetic result and low recurrence rate. Methods A retrospective analysis of 19 patients with IGLM is performed based on the findings of clinical, radiological, and pathological examinations. The results of two treatments are presented: medical treatment with oral corticosteroids, and consecutive surgical excision after a follow-up period of 20 months (range, 6-75 months). Results The majority of patients treated in this paper were young (mean, 34 years) parous women with a history of hormonal medication use. The main clinical finding is large, irregular, and painful mass. Hypoechoic lobulated, irregular tubular or oval shaped masses had been imaged by ultrasound. Mammographic findings were an ill-defined mass, enlarged axillary lymph nodes, asymmetric density, and architectural distortion. Diagnoses of IGLM had been established by cytological or histological examination. Symptoms subside and inflammatory changes regressed with medical treatment. The remaining lesions were excised by consecutive breast conserving surgery. The disease recurred in one patient during the follow-up period. Conclusion IGLM is an inflammatory breast disease found in young women who present with a large painful irregular mass, which mimics carcinoma, as a physical change. Breast imaging modalities are not helpful to differentiate IGLM from invasive cancer. The correct diagnosis is established by cytological or histological examination. Medical treatment with corticosteroids provides significant regression of the inflammatory disease, allowing more conservative surgery. Consecutive surgical excision of the remaining lesions with good cosmetic results provides definitive treatment and reduces the risk of recurrence. PMID:22493638

VHF and UHF radar observations of equatorial F region ionospheric irregularities and background densities

NASA Astrophysics Data System (ADS)

Towle, D. M.

1980-02-01

A series of measurements of the properties of equatorial ionospheric irregularities were made at Kwajalein, Marshall Islands (M.I.) in August 1977 and July-August 1978. These measurements, sponsored by the Defense Nuclear Agency (DNA), involved coordinated ground-based and in situ sensors. The ARPA Long-Range Tracking and Instrumentation Radar (ALTAIR), operated by Lincoln Laboratory, obtained backscatter and transmission data during five nights in August 1977 and eight nights in July-August 1978. This report describes the ALTAIR data from the night of August 11, 1978, which yield direct quantitative measurements of 1-m and 3/8-m irregularities and of plasma depleted regions. These plasma depleted regions, previously predicted on the basis of theoretical analysis and in situ data, were observed during the decay phase and not the generative phase of the field-aligned irregularities.

DC Electric Fields, Associated Plasma Drifts, and Irregularities Observed on the C/NOFS Satellite

NASA Technical Reports Server (NTRS)

Pfaff, R.; Freudenreich, H.; Klenzing, J.

2011-01-01

Results are presented from the Vector Electric Field Investigation (VEFI) on the Air Force Communication/Navigation Outage Forecasting System (C/NOFS) satellite, a mission designed to understand, model, and forecast the presence of equatorial ionospheric irregularities. The VEFI instrument includes a vector DC electric field detector, a fixed-bias Langmuir probe operating in the ion saturation regime, a flux gate magnetometer, an optical lightning detector, and associated electronics including a burst memory. Compared to data obtained during more active solar conditions, the ambient DC electric fields and their associated E x B drifts are variable and somewhat weak, typically < 1 mV/m. Although average drift directions show similarities to those previously reported, eastward/outward during day and westward/downward at night, this pattern varies significantly with longitude and is not always present. Daytime vertical drifts near the magnetic equator are largest after sunrise, with smaller average velocities after noon. Little or no pre-reversal enhancement in the vertical drift near sunset is observed, attributable to the solar minimum conditions creating a much reduced neutral dynamo at the satellite altitude. The nighttime ionosphere is characterized by larger amplitude, structured electric fields, even where the plasma density appears nearly quiescent. Data from successive orbits reveal that the vertical drifts and plasma density are both clearly organized with longitude. The spread-F density depletions and corresponding electric fields that have been detected thus far have displayed a preponderance to appear between midnight and dawn. Associated with the narrow plasma depletions that are detected are broad spectra of electric field and plasma density irregularities for which a full vector set of measurements is available for detailed study. The VEFI data represents a new set of measurements that are germane to numerous fundamental aspects of the electrodynamics and irregularities inherent to the Earth s low latitude ionosphere.

Dense cloud cores revealed by CO in the low metallicity dwarf galaxy WLM.

PubMed

Rubio, Monica; Elmegreen, Bruce G; Hunter, Deidre A; Brinks, Elias; Cortés, Juan R; Cigan, Phil

2015-09-10

Understanding stellar birth requires observations of the clouds in which they form. These clouds are dense and self-gravitating, and in all existing observations they are molecular, with H2 the dominant species and carbon monoxide (CO) the best available tracer. When the abundances of carbon and oxygen are low compared with that of hydrogen, and the opacity from dust is also low, as in primeval galaxies and local dwarf irregular galaxies, CO forms slowly and is easily destroyed, so it is difficult for it to accumulate inside dense clouds. Here we report interferometric observations of CO clouds in the local group dwarf irregular galaxy Wolf-Lundmark-Melotte (WLM), which has a metallicity that is 13 per cent of the solar value and 50 per cent lower than the previous CO detection threshold. The clouds are tiny compared to the surrounding atomic and H2 envelopes, but they have typical densities and column densities for CO clouds in the Milky Way. The normal CO density explains why star clusters forming in dwarf irregulars have similar densities to star clusters in giant spiral galaxies. The low cloud masses suggest that these clusters will also be low mass, unless some galaxy-scale compression occurs, such as an impact from a cosmic cloud or other galaxy. If the massive metal-poor globular clusters in the halo of the Milky Way formed in dwarf galaxies, as is commonly believed, then they were probably triggered by such an impact.

The Role of Hydromagnetic Waves in the Magnetosphere and the Ionosphere

DTIC Science & Technology

1988-05-01

ionospheric heating ex- ( MINIX ) was carried out recently by the Kyoto Uni- periments [Stubbe and Kopka, 198! Stubbe et al., versity group in Japan to...ionospheric irregularities and other predicted netosphere with growth times of a few minutes. Our phenomena could not be produced in MINIX be- work...ionosphere: Project- HF produced electron density irregularities in the polar iono- MINIX for future solar power satellite, paper presented at 21st

Remote double resonance coupling of radar energy to ionospheric irregularities

NASA Technical Reports Server (NTRS)

Kennel, C. F.

1971-01-01

Experimental results indicate that low frequency modulation of a high power radar beam, tuned to one of the critical frequencies of the ionosphere, may produce field-aligned density irregularities when the modulation frequency matches an ionospheric eigenfrequency. By choosing the radar carrier frequency and polarization, a number of interaction layers were selected. The variety of possible excitations shows that the double resonance technique may be adaptable to a number of different objectives.

Report on the HAARP 2008 Winter Campaign Focusing on Artificial Ionospheric Irregularities

DTIC Science & Technology

2008-07-31

Figure Bl. Magnetic field variations recorded by the fluxgate magnetometer 30 Figure B2. Composite ionogram showing the variation of the reflection...variation was monitored by the Fluxgate Magnetometer . The density irregularities were monitored by the Ionosonde. 20:00 Preliminary Results The...magnetic field variations in three directions (H, D, and Z) recorded by the fluxgate magnetometer from UTC 20:00 to 04:00 are shown in the plots of

Electric Field and Plasma Density Observations of Irregularities and Plasma Instabilities in the Low Latitude Ionosphere Gathered by the C/NOFS Satellite

NASA Technical Reports Server (NTRS)

Pfaff, Robert F.; Freudenreich, H.; Rowland, D.; Klenzing, J.; Liebrecht, C.

2012-01-01

The Vector Electric Field Investigation (VEFI) on the C/NOFS equatorial satellite provides a unique data set which includes detailed measurements of irregularities associated with the equatorial ionosphere and in particular with spread-F depletions. We present vector AC electric field observations gathered on C/NOFS that address a variety of key questions regarding how plasma irregularities, from meter to kilometer scales, are created and evolve. The talk focuses on occasions where the ionosphere F-peak has been elevated above the C/NOFS satellite perigee of 400 km as solar activity has increased. In particular, during the equinox periods of 2011, the satellite consistently journeyed below the F-peak whenever the orbit was in the region of the South Atlantic anomaly after sunset. During these passes, data from the electric field and plasma density probes on the satellite have revealed two types of instabilities which had not previously been observed in the C/NOFS data set: The first is evidence for 400-500km-scale bottomside "undulations" that appear in the density and electric field data. In one case, these large scale waves are associated with a strong shear in the zonal E x B flow, as evidenced by variations in the meridional (outward) electric fields observed above and below the F-peak. These undulations are devoid of smaller scale structures in the early evening, yet appear at later local times along the same orbit associated with fully-developed spread-F with smaller scale structures. This suggests that they may be precursor waves for spread-F, driven by a collisional shear instability, following ideas advanced previously by researchers using data from the Jicamarca radar. A second result is the appearance of km-scale irregularities that are a common feature in the electric field and plasma density data that also appear when the satellite is near or below the F-peak at night. The vector electric field instrument on C/NOFS clearly shows that the electric field component of these waves is strongest in the zonal direction. These waves are strongly correlated with simultaneous observations of plasma density oscillations and appear both with, and without, evidence of larger-scale spread-F depletions. These km-scale, quasi-coherent waves strongly resemble the bottomside, sinusoidal irregularities reported in the Atmosphere Explorer satellite data set by Valladares et al. and are believed to cause scintillations of VHF radiowaves. We interpret these new observations in terms of fundamental plasma instabilities associated with the unstable, nighttime equatorial ionosphere.

Imaging irregular magma reservoirs with InSAR and GPS observations: Application to Kilauea and Copahue volcanoes

NASA Astrophysics Data System (ADS)

Lundgren, P.; Camacho, A.; Poland, M. P.; Miklius, A.; Samsonov, S. V.; Milillo, P.

2013-12-01

The availability of synthetic aperture radar (SAR) interferometry (InSAR) data has increased our awareness of the complexity of volcano deformation sources. InSAR's spatial completeness helps identify or clarify source process mechanisms at volcanoes (i.e. Mt. Etna east flank motion; Lazufre crustal magma body; Kilauea dike complexity) and also improves potential model realism. In recent years, Bayesian inference methods have gained widespread use because of their ability to constrain not only source model parameters, but also their uncertainties. They are computationally intensive, however, which tends to limit them to a few geometrically rather simple source representations (for example, spheres). An alternative approach involves solving for irregular pressure and/or density sources from a three-dimensional (3-D) grid of source/density cells. This method has the ability to solve for arbitrarily shaped bodies of constant absolute pressure/density difference. We compare results for both Bayesian (a Markov chain Monte Carlo algorithm) and the irregular source methods for two volcanoes: Kilauea, Hawaii, and Copahue, Argentina-Chile border. Kilauea has extensive InSAR and GPS databases from which to explore the results for the irregular method with respect to the Bayesian approach, prior models, and an extensive set of ancillary data. One caveat, however, is the current restriction in the irregular model inversion to volume-pressure sources (and at a single excess pressure change), which limits its application in cases where sources such as faults or dikes are present. Preliminary results for Kilauea summit deflation during the March 2011 Kamoamoa eruption suggests a northeast-elongated magma body lying roughly 1-1.5 km below the surface. Copahue is a southern Andes volcano that has been inflating since early 2012, with intermittent summit eruptive activity since late 2012. We have an extensive InSAR time series from RADARSAT-2 and COSMO-SkyMed data, although both are from descending tracks. Preliminary modeling suggests a very irregular magma body that extends from the volcanic edifice to less than 5 km depth and located slightly north of the summit at shallow depths but to the ENE at greater depths. In our preliminary analysis, we find that there are potential limitations and trade-offs in the Bayesian results that suggest the simplicity of the assumed analytic source may generate systematic biases in source parameters. Instead, the irregular 3-D solution appears to provide greater realism, but is limited in the number and type of sources that can be modeled.

Fractal analysis of plaque border, a novel method for the quantification of atherosclerotic plaque contour irregularity, is associated with pro-atherogenic plasma lipid profile in subjects with non-obstructive carotid stenoses.

PubMed

Moroni, Francesco; Magnoni, Marco; Vergani, Vittoria; Ammirati, Enrico; Camici, Paolo G

2018-01-01

Plaque border irregularity is a known imaging characteristic of vulnerable plaques, but its evaluation heavily relies on subjective evaluation and operator expertise. Aim of the present work is to propose a novel fractal-analysis based method for the quantification of atherosclerotic plaque border irregularity and assess its relation with cardiovascular risk factors. Forty-two asymptomatic subjects with carotid stenosis underwent ultrasound evaluation and assessment of cardiovascular risk factors. Total, low-density lipoprotein (LDL), high-density lipoprotein (HDL) plasma cholesterol and triglycerides concentrations were measured for each subject. Fractal analysis was performed in all the carotid segments affected by atherosclerosis, i.e. 147 segments. The resulting fractal dimension (FD) is a measure of irregularity of plaque profile on long axis view of the plaque. FD in the severest stenosis (main plaque FD,mFD) was 1.136±0.039. Average FD per patient (global FD,gFD) was 1.145±0.039. FD was independent of other plaque characteristics. mFD significantly correlated with plasma HDL (r = -0.367,p = 0.02) and triglycerides-to-HDL ratio (r = 0.480,p = 0.002). Fractal analysis is a novel, readily available, reproducible and inexpensive technique for the quantitative measurement of plaque irregularity. The correlation between low HDL levels and plaque FD suggests a role for HDL in the acquisition of morphologic features of plaque instability. Further studies are needed to validate the prognostic value of fractal analysis in carotid plaques evaluation.

Risk of Sjögren's syndrome in Taiwanese female adults with irregular menstrual cycles: a population-based case-control study.

PubMed

Lu, Ming-Chi; Hsieh, Min-Chih; Koo, Malcolm; Lai, Ning-Sheng

2016-01-01

Primary Sjögren's syndrome (pSS) is a progressive systemic autoimmune disorder with a strong female predominance. Hormonal influences are thought to play a role in the development of pSS. However, no studies have specifically evaluated the association between irregular menstrual cycles and pSS. Therefore, using a health claims database, this study investigated the risk of pSS in women with irregular menstrual cycles. We conducted a case-control study using the Taiwan's National Health Insurance Research Database. A total of 360 patients diagnosed with pSS (International Classification of Diseases, ninth revision, clinical modification, ICD-9-CM code 710.2) between 2001 and 2012 were identified. Controls were frequency-matched at a rate of 5:1 to the cases by five-year age interval and index year. Both cases and controls were retrospectively traced back until 2001 for the diagnosis of irregular menstrual cycles (ICD-9-CM code 626.4). The risk of pSS was assessed using multivariate logistic regression analyses. Irregular menstrual cycles were significantly associated with pSS [adjusted odds ratio, (AOR) = 1.38, p = 0.027], after adjusted for insured amount, urbanization level, and thyroid disorder. In addition, when the data were stratified by three age categories, only the patients in the age category of 45-55 years showed significant association between irregular menstrual cycles and pSS (AOR = 1.74, p = 0.005). In this nationwide, population-based case-control study, we found a significant increased risk of pSS in female patients with irregular menstrual cycles, particularly those in their mid-forties to mid-fifties.

Small-scale plasma turbulence and intermittency in the high latitude F region based on the ICI-2 sounding rocket experiment

NASA Astrophysics Data System (ADS)

Spicher, A.; Miloch, W.; Moen, J. I.; Clausen, L. B. N.

2015-12-01

Small-scale plasma irregularities and turbulence are common phenomena in the F layer of the ionosphere, both in the equatorial and polar regions. A common approach in analyzing data from experiments on space and ionospheric plasma irregularities are power spectra. Power spectra give no information about the phases of the waveforms, and thus do not allow to determine whether some of the phases are correlated or whether they exhibit a random character. The former case would imply the presence of nonlinear wave-wave interactions, while the latter suggests a more turbulent-like process. Discerning between these mechanisms is crucial for understanding high latitude plasma irregularities and can be addressed with bispectral analysis and higher order statistics. In this study, we use higher order spectra and statistics to analyze electron density data observed with the ICI-2 sounding rocket experiment at a meter-scale resolution. The main objective of ICI-2 was to investigate plasma irregularities in the cusp in the F layer ionosphere. We study in detail two regions intersected during the rocket flight and which are characterized by large density fluctuations: a trailing edge of a cold polar cap patch, and a density enhancement subject to cusp auroral particle precipitation. While these two regions exhibit similar power spectra, our analysis reveals that their internal structure is different. The structures on the edge of the polar cap patch are characterized by significant coherent mode coupling and intermittency, while the plasma enhancement associated with precipitation exhibits stronger random characteristics. This indicates that particle precipitation may play a fundamental role in ionospheric plasma structuring by creating turbulent-like structures.

A Review of Ionospheric Scintillation Models.

PubMed

Priyadarshi, S

This is a general review of the existing climatological models of ionospheric radio scintillation for high and equatorial latitudes. Trans-ionospheric communication of radio waves from transmitter to user is affected by the ionosphere which is highly variable and dynamic in both time and space. Scintillation is the term given to irregular amplitude and phase fluctuations of the received signals and related to the electron density irregularities in the ionosphere. Key sources of ionospheric irregularities are plasma instabilities; every irregularities model is based on the theory of radio wave propagation in random media. It is important to understand scintillation phenomena and the approach of different theories. Therefore, we have briefly discussed the theories that are used to interpret ionospheric scintillation data. The global morphology of ionospheric scintillation is also discussed briefly. The most important (in our opinion) analytical and physical models of scintillation are reviewed here.

Reexamining X-mode suppression and fine structure in artificial E region field-aligned plasma density irregularities

NASA Astrophysics Data System (ADS)

Miceli, R. J.; Hysell, D. L.; Munk, J.; McCarrick, M.; Huba, J. D.

2013-09-01

Artificial field-aligned plasma density irregularities (FAIs) were generated in the E region of the ionosphere above the High Frequency Active Auroral Research Program facility during campaigns in May and August of 2012 and observed using a 30 MHz coherent scatter radar imager in Homer, Alaska. The purpose of this ionospheric modification experiment was to measure the threshold pump power required to excite thermal parametric instabilities by O-mode heating and to investigate the suppression of the FAIs by simultaneous X-mode heating. We find that the threshold pump power for irregularity excitation was consistent with theoretical predictions and increased by approximately a factor of 2 when X-mode heating was present. A modified version of the Another Model of the Ionosphere (SAMI2) ionospheric model was used to simulate the threshold experiments and suggested that the increase was entirely due to enhanced D region absorption associated with X-mode heating. Additionally, a remarkable degree of fine structure possibly caused by natural gradient drift instability in the heater-modified volume was observed in experiments performed during geomagnetically active conditions.

Internal structure of shock waves in disparate mass mixtures

NASA Technical Reports Server (NTRS)

Chung, Chan-Hong; De Witt, Kenneth J.; Jeng, Duen-Ren; Penko, Paul F.

1992-01-01

The detailed flow structure of a normal shock wave for a gas mixture is investigated using the direct-simulation Monte Carlo method. A variable diameter hard-sphere (VDHS) model is employed to investigate the effect of different viscosity temperature exponents (VTE) for each species in a gas mixture. Special attention is paid to the irregular behavior in the density profiles which was previously observed in a helium-xenon experiment. It is shown that the VTE can have substantial effects in the prediction of the structure of shock waves. The variable hard-sphere model of Bird shows good agreement, but with some limitations, with the experimental data if a common VTE is chosen properly for each case. The VDHS model shows better agreement with the experimental data without adjusting the VTE. The irregular behavior of the light-gas component in shock waves of disparate mass mixtures is observed not only in the density profile, but also in the parallel temperature profile. The strength of the shock wave, the type of molecular interactions, and the mole fraction of heavy species have substantial effects on the existence and structure of the irregularities.

Understanding Transient Forcing with Plasma Instability Model, Ionospheric Propagation Model and GNSS Observations

NASA Astrophysics Data System (ADS)

Deshpande, K.; Zettergren, M. D.; Datta-Barua, S.

2017-12-01

Fluctuations in the Global Navigation Satellite Systems (GNSS) signals observed as amplitude and phase scintillations are produced by plasma density structures in the ionosphere. Phase scintillation events in particular occur due to structures at Fresnel scales, typically about 250 meters at ionospheric heights and GNSS frequency. Likely processes contributing to small-scale density structuring in auroral and polar regions include ionospheric gradient-drift instability (GDI) and Kelvin-Helmholtz instability (KHI), which result, generally, from magnetosphere-ionosphere interactions (e.g. reconnection) associated with cusp and auroral zone regions. Scintillation signals, ostensibly from either GDI or KHI, are frequently observed in the high latitude ionosphere and are potentially useful diagnostics of how energy from the transient forcing in the cusp or polar cap region cascades, via instabilities, to small scales. However, extracting quantitative details of instabilities leading to scintillation using GNSS data drastically benefits from both a model of the irregularities and a model of GNSS signal propagation through irregular media. This work uses a physics-based model of the generation of plasma density irregularities (GEMINI - Geospace Environment Model of Ion-Neutral Interactions) coupled to an ionospheric radio wave propagation model (SIGMA - Satellite-beacon Ionospheric-scintillation Global Model of the upper Atmosphere) to explore the cascade of density structures from medium to small (sub-kilometer) scales. Specifically, GEMINI-SIGMA is used to simulate expected scintillation from different instabilities during various stages of evolution to determine features of the scintillation that may be useful to studying ionospheric density structures. Furthermore we relate the instabilities producing GNSS scintillations to the transient space and time-dependent magnetospheric phenomena and further predict characteristics of scintillation in different geophysical situations. Finally we present initial comparison of our modeling results with GNSS scintillation observed via an array of receivers at Poker Flat.

Investigation of the role of plasma wave cascading processes in the formation of midlatitude irregularities utilizing GPS and radar observations

NASA Astrophysics Data System (ADS)

Eltrass, A.; Scales, W. A.; Erickson, P. J.; Ruohoniemi, J. M.; Baker, J. B. H.

2016-06-01

Recent studies reveal that midlatitude ionospheric irregularities are less understood due to lack of models and observations that can explain the characteristics of the observed wave structures. In this paper, the cascading processes of both the temperature gradient instability (TGI) and the gradient drift instability (GDI) are investigated as the cause of these irregularities. Based on observations obtained during a coordinated experiment between the Millstone Hill incoherent scatter radar and the Blackstone Super Dual Auroral Radar Network radar, a time series for the growth rate of both TGI and GDI is calculated for observations in the subauroral ionosphere under both quiet and disturbed geomagnetic conditions. Recorded GPS scintillation data are analyzed to monitor the amplitude scintillations and to obtain the spectral characteristics of irregularities producing ionospheric scintillations. Spatial power spectra of the density fluctuations associated with the TGI from nonlinear plasma simulations are compared with both the GPS scintillation spectral characteristics and previous in situ satellite spectral measurements. The spectral comparisons suggest that initially, TGI or/and GDI irregularities are generated at large-scale size (kilometer scale), and the dissipation of the energy associated with these irregularities occurs by generating smaller and smaller (decameter scale) irregularities. The alignment between experimental, theoretical, and computational results of this study suggests that in spite of expectations from linear growth rate calculations, cascading processes involving TGI and GDI are likely responsible for the midlatitude ionospheric irregularities associated with GPS scintillations during disturbed times.

Ionospheric Irregularities Characterization by Ground and Space-based GPS Observations

NASA Astrophysics Data System (ADS)

Zakharenkova, I.; Cherniak, I.; Krankowski, A.

2017-12-01

We present new results on detection and investigation of the topside ionospheric irregularities using GPS measurements from Precise Orbit Determination (POD) GPS antenna onboard Low Earth Orbit satellites. Our investigation is based on the recent ESA's Swarm mission launched on 22 November 2013 and consisted of three identical satellites, two of them fly in a tandem at an orbit altitude of 460 km while the third satellite - at an orbit altitude of 510 km. Each satellite is equipped with a zenith-looking antenna and 8-channel dual-frequency GPS receiver that delivered 1 Hz data for POD purposes, as well as Langmuir Probe instrument for in situ electron density. Additionally, we have analyzed GPS measurements onboard GRACE and TerraSAR-X satellite, which have rather similar to Swarm orbit altitude of 500 km. GPS measurements onboard MetOP-A and MetOP-B satellites (altitude of 840 km) can complement these observations in order to estimate an altitudinal extent of the ionospheric irregularities penetrating to higher altitudes. We demonstrate that space-based GPS observations can be effectively used for monitoring of the topside ionospheric irregularities occurrence in both high-latitude and equatorial regions and may essentially contribute to the multi-instrumental analysis of the ground-based and in situ data. Climatological characteristics of the equatorial ionospheric irregularities occurrence probability are derived from POD GPS measurements for all longitudinal sectors for the years 2013-2016. Several examples of strong geomagnetic storms, including the 2015 St. Patrick's Day storm, were analyzed to demonstrate differences between the climatlogical characteristics in space-based GPS data and storm-induced equatorial irregularities observations (postsunset suppression, night/morning-time occurrence). To support our observations and conclusions, we involve into our analysis in situ plasma density provided by Swarm constellation, GRACE KBR, DMSP satellites, as well as ground-based GNSS and digisonde networks. New International GNSS Service (IGS) product - the Northern Hemisphere GPS-based ROTI (rate of the TEC index) maps - was analyzed to determine similarities and differences in ionospheric irregularities signatures in the ground and space-based GPS observations.

Radio Aurora Explorer : Mission overview and the science objectives

NASA Astrophysics Data System (ADS)

Bahcivan, H.; Cutler, J.; Buonocore, J.; Bennett, M.

2009-12-01

Radio Aurora Explorer (RAX) is the first CubeSat mission funded by the NSF Small Satellite Program as a collaborative research of SRI International and the University of Michigan. The mission is a ground-to-space bi-static radar experiment enabling exploration of small-scale turbulent ionospheric structures in the high latitudes not accessible from the ground or space alone. The primary science objective is to understand the microphysics of plasma instabilities that lead to meter-scale plasma turbulence in the form of field-aligned irregularities of electron density between the altitudes of 80 and 400 km. The best-known radar target for the mission is the Farley-Buneman (two-stream) instability occurring in the ionospheric E region when the convection electric field exceeds a threshold of ~20 mV/m. Other targets include spiky structures associated with electrostatic ion cyclotron waves, Post-Rosenbluth, lower, and upper hybrid waves. The science objectives are (1) to determine the altitude distribution of high-latitude ionospheric irregularities as a function of the convection electric field magnitude and direction, (2) to identify the plasma waves responsible for the scattering, and (3) to determine to what extent the irregularities are field-aligned? The mission will measure for the first time the 3-D k-spectrum of the irregularities, in particular measuring their magnetic field alignment. The irregularities will be irradiated by an incoherent scatter radar (PFISR for the first experiments) and the scattered radiation will form a hallow cone-shaped radio aurora into space as illustrated in the figure below. The satellite radar receiver will the scattered signals as the satellite passes through the radio aurora. Irregularity locations will be determined using the time delay between ISR transmissions and satellite receptions. Experiments throughout the lifetime of the mission will determine irregularity intensities as a function altitude, magnetic aspect angle, and as a function of plasma parameters such as convection electric field, plasma density, and temperatures, which are measured effectively simultaneously by the ISR. In this regard, the mission is a well-controlled plasma experiment in a wall-less laboratory.

SuperDARN HF Scattering and Propagation in the Presence of Polar Patches Imaged Using RISR

NASA Astrophysics Data System (ADS)

Gillies, R. G.; Perry, G. W.; Varney, R. H.; Gillies, D. M.; Donovan, E.

2017-12-01

The global array of High Frequency (HF) Super Dual Auroral Radar Network (SuperDARN) radars continuously monitors ionospheric convection in the middle-to-high latitude region. The radars measure coherent backscatter from decameter scale field-aligned irregularities. One of the main generation mechanisms for these field-aligned irregularities is the gradient drift instability (GDI). The edges of ionospheric density structures, such as polar cap patches, provide ideal locations for GDI growth. The geometry required for GDI growth results in irregularities forming on the trailing edge of polar patches. However, irregularities generated by the non-linear evolution of the GDI can become prevalent throughout the patch within minutes. Modelling the irregularity growth and measurements of backscatter within patches have both confirmed this. One aspect that has often been overlooked in studies of coherent backscatter within patches is the effect of HF propagation on echo location. This study examines HF echo locations in the vicinity of patches that were imaged using the Resolute Bay Incoherent Scatter Radars (RISR). The effect of both vertical and lateral refraction of the HF wave on echo location is examined.

Cause of different local time distribution in the postsunset equatorial ionospheric irregularity occurrences between June and December solstices

NASA Astrophysics Data System (ADS)

Su, S.-Y.; Chao, C. K.; Liu, C. H.

2009-04-01

Global averaged postsunset equatorial ionospheric density irregularity occurrences observed by ROCSAT during the moderate to high solar activity years of 1999 to 2004 indicate a different local time distribution between June and December solstices. The irregularity occurrences during the December solstice show a faster increase rate to peak at 2100-2200 local time, while the irregularity occurrences during the June solstice have a slower increase rate and peak one hour later in local time than that in the December solstice. The cause of such different local time distributions is attributed to a large contrast in the time of zonal drift reversal and the magnitude of postsunset vertical drift observed by ROCSAT at longitudes of large magnetic declination in the two solstices. That is, a delay in the zonal drift reversal in association with a smaller postsunset vertical drift observed at longitudes of positive magnetic declination has greatly inhibited the irregularity occurrences during the June solstice in contrast to an earlier zonal drift reversal together with a large vertical drift occurring at longitudes of negative magnetic declination to accelerate the irregularity occurrences during the December solstice. We think that the different geomagnetic field strengths that existed between the longitudes of positive and negative magnetic declinations have played a crucial role in determining the different local time distributions of irregularity occurrences for the two solstices.

Analytic Expressions for the Gravity Gradient Tensor of 3D Prisms with Depth-Dependent Density

NASA Astrophysics Data System (ADS)

Jiang, Li; Liu, Jie; Zhang, Jianzhong; Feng, Zhibing

2017-12-01

Variable-density sources have been paid more attention in gravity modeling. We conduct the computation of gravity gradient tensor of given mass sources with variable density in this paper. 3D rectangular prisms, as simple building blocks, can be used to approximate well 3D irregular-shaped sources. A polynomial function of depth can represent flexibly the complicated density variations in each prism. Hence, we derive the analytic expressions in closed form for computing all components of the gravity gradient tensor due to a 3D right rectangular prism with an arbitrary-order polynomial density function of depth. The singularity of the expressions is analyzed. The singular points distribute at the corners of the prism or on some of the lines through the edges of the prism in the lower semi-space containing the prism. The expressions are validated, and their numerical stability is also evaluated through numerical tests. The numerical examples with variable-density prism and basin models show that the expressions within their range of numerical stability are superior in computational accuracy and efficiency to the common solution that sums up the effects of a collection of uniform subprisms, and provide an effective method for computing gravity gradient tensor of 3D irregular-shaped sources with complicated density variation. In addition, the tensor computed with variable density is different in magnitude from that with constant density. It demonstrates the importance of the gravity gradient tensor modeling with variable density.

The Vector Electric Field Instrument on the C/NOFS Satellite

NASA Technical Reports Server (NTRS)

Pfaff, R.; Kujawski, J.; Uribe, P.; Bromund, K.; Fourre, R.; Acuna, M.; Le, G.; Farrell, W.; Holzworth, R.; McCarthy, M.;

Formation of stimulated electromagnetic emission of the ionosphere: laboratory modeling

NASA Astrophysics Data System (ADS)

Starodubtsev, Mikhail; Kostrov, Alexander; Nazarov, Vladimir

Laboratory modeling of some physical processes involved in generation of the stimulated elec-tromagnetic emission (SEE) is presented. SEE is a noise component observed in the spectrum of the pump electromagnetic wave reflected from the heated ionosphere during the ionospheric heating experiments. In our laboratory experiments, main attention has been paid to the experimental investigation of generation of the most pronounced SEE components connected to the small-scale filamentation of the heated area of the ionosphere. It has been shown that the main physical mechanism of thermal magnetoplasma nonlinearity in this frequency range is due to thermal self-channeling of the Langmuir waves. This mechanism has the minimal threshold and should appear when both laboratory and ionospheric plasmas are heated by high-power radiowaves. Thermal self-channeling of Langmuir waves is connected with the fact that Langmuir waves are trapped in the area of depleted plasma density. As a result, wave amplitude significantly increases in these depleted ragion, which lead to the local plasma heating and, consequently, to the deepening of the plasma density depletion due to plasma thermo-diffusion. As the result, narrow, magnetic-field-aligned plasma density irregularities are formed in a magnetoplasma. Self-channelled Langmuir waves exhibit well-pronoused spectral satellites shifted by 1-2 MHz from the fundamental frequency (about 700 MHz in our experimental conditions). It has been found that there exist two main mechanisms of satellite formation. First mechanism (dynamic) has been observed during the formation of the small-scale irregularity, when its longitudinal size increases fastly. During this process, spectrum of the trapped wave characterizes by one low-frequency satellite. Physical mechanism, which lead to the formation of this satellite is connected to Doppler shift of the frequency of Langmuir waves trapped in the non-stationar plasma irregularity. Second mechanism (stationary) has been observed in the case of the devel-oped irregularity, i.e. when its shape is close to the cylindrical one. In this regime, spectrum of the trapped wave is characterized by two symmetric (Stokes and anti-Stokes) spectral satellites. It has been proposed that generation of these satellites is connected with scattering of trapped Langmuir waves on the drift oscillations of the irregularity.

Observations of mesospheric turbulence by rocket probe and VHF radar, part 2.4A

NASA Astrophysics Data System (ADS)

Royrvik, O.; Smith, L. G.

1984-12-01

Data from the Jicamarca VHF radar and from a Languir probe fine-structure on a Nike Orion rocket launched from Punto Lobos, Peru, have been compared. A single mesospheric scattering layer was observed by the radar. The Langmuir probe detected irregularities in the electron-density profile in a narrow region between 85.2 and 86.6 km. It appears from a comparison between these two data sets that turbulence in the neutral atmosphere is the mechanism generating the refractive index irregularities.

Observations of Mesospheric Turbulence by Rocket Probe and VHF Radar, Part 2.4A

NASA Technical Reports Server (NTRS)

Royrvik, O.; Smith, L. G.

1984-01-01

Data from the Jicamarca VHF radar and from a Languir probe fine-structure on a Nike Orion rocket launched from Punto Lobos, Peru, have been compared. A single mesospheric scattering layer was observed by the radar. The Langmuir probe detected irregularities in the electron-density profile in a narrow region between 85.2 and 86.6 km. It appears from a comparison between these two data sets that turbulence in the neutral atmosphere is the mechanism generating the refractive index irregularities.

Shack-Hartmann Electron Densitometer (SHED): An Optical System for Diagnosing Free Electron Density in Laser-Produced Plasmas

DTIC Science & Technology

2016-11-01

a few nanoseconds. The challenge remains to diagnose plasmas via the free electron density in this short window of time and often in a small volume ...Free Electron Density in Laser-Produced Plasmas by Anthony R Valenzuela Approved for public release; distribution is...US Army Research Laboratory Shack-Hartmann Electron Densitometer (SHED): An Optical System for Diagnosing Free Electron Density in Laser

Characteristics and climatology of mid-latitude F-region ionospheric irregularities observed by COSMIC radio occultation measurements

NASA Astrophysics Data System (ADS)

Watson, C.; Pedatella, N. M.

2017-12-01

Small-medium scale ( 1-50 km) ionospheric plasma irregularities are a ubiquitous feature of the earth's F region ionosphere. COSMIC radio occultation measurements provide a valuable opportunity to improve upon the incomplete global observational picture of irregularity occurrence and characteristics. A climatological database of ionospheric irregularities and their characteristics (e.g. magnitude, scale size, gradient, and associated scintillation) has been developed through detection of total electron content (TEC) perturbations by COSMIC precise orbit determination (POD) antennas and associated receivers. Vertical scale sizes ranging from 1 to 50 km were resolved from 1 Hz TEC measurements stored in podTec files. Amplitude scintillation index (S4) of ScnLv1 files was used as a proxy for the occurrence of smaller scale (<1 km) scintillation producing structures. Four years of processed data (2007-2008 and 2012-2013) has revealed interesting climatological features of irregularity occurrence and characteristics. The presentation will focus on the results at mid-latitudes. One interesting mid-latitude feature is a high occurrence of irregularities in regions corresponding to the solar terminator. Perturbations larger than 0.1 TEC units (TECU) were observed 50%-80% of the time in terminator regions, with higher occurrence and more intense perturbations around sunset and during years of high solar activity. Altitude of peak occurrence of terminator irregularities was about 150 km, with a sharp upper-altitude cut-off of 250 km. The occurrence and characteristics of these irregularities are modified according to proximity to solar terminator location. A possible link to thermospheric neutral density perturbations also associated with the solar terminator will be discussed. The climatology of non-terminator mid-latitude irregularities is consistent with previous observations of mid-latitude field-aligned irregularities (FAIs), including a local-time dependent altitude and a peak occurrence in the summer hemisphere. The characteristics of these non-terminator irregularities will also be discussed.

How and in Which way Space Weather Changed the Ionospheric Irregularities Occurrence During the St. Patricḱs Storm

NASA Astrophysics Data System (ADS)

Fagundes, P. R.; Barbosa, F. R. E., Sr.; Kavutarapu, V.; Fejer, B. G.; Pillat, V. G.; De Nardin, C. M.; Muella, M.

2017-12-01

During the solar cycle 24 there was a very intense geomagnetic storm, called St. Patricḱs Day storm and the effects of this storm on ionosphere has become a topic of extensive space weather investigation. The Dst during this storm reached -223 nT on March 17, 2015 at 23:00 UT. Special efforts have been devoted so far to investigate many aspects of the St. Patricḱs Day ionospheric storm such as the prompt penetration electric fields (PPEFs), GPS-TEC changes, electron density disturbances, plasma drift, O+ concentration modification, hemispherical asymmetry developments, equatorial ionization anomaly (EIA) modification, and ionospheric irregularities. Besides all these important studies, there are some essential aspects, which have not been addressed yet, related to the occurrence of ionospheric irregularities with different scale sizes. In this paper, we present and discuss the generation and suppression of ionospheric irregularities during March 2015, using the observations conducted in the Latin American Sector from 4 ionosondes (ESF) and 20 GPS-TEC stations (ROT phase fluctuation), which includes the St. Patricḱs Day geomagnetic storm period. Suppression of large-small scales ionospheric irregularities has occurred during the main and second night of the recovery phases. However, during the first night of recovery phase there was post-midnight ionospheric irregularities.

Understanding of the sources of the F-region field-aligned irregularities in the middle latitude using ground-based and satellite observations

NASA Astrophysics Data System (ADS)

Kwak, Y. S.; Kil, H.; Yang, T. Y.; Park, J.; Choi, J. M.

2017-12-01

The electron density irregularities in the F region are problematic in satellite communication and navigation systems. Extensive efforts have been made to understand the onset conditions and sources of such irregularities and to predict or avoid the impact of these irregularities on the society. A VHF radar was built at Daejeon (36.2°N, 127.1°E, 26.7°N dip latitude) in South Korea in December 2009 to study the characteristics and source of the irregularities in middle latitudes. Our study investigates the occurrence climatology of the field-aligned irregularities (FAIs) and their association with medium-scale traveling ionospheric disturbances (MSTIDs) and sporadic E. The activity of FAIs is investigated with the Daejeon radar data acquired in 2010-2016, and the occurrences of MSTIDs and sporadic E are monitored with the total electron content maps over Japan and ionosonde data at Icheon in South Korea, respectively. Swarm satellite observations are used to investigate the field-aligned properties in the F-region FAIs. Through the comparison of the activities of F-region FAIs, MSTIDs, and sporadic E, we assess the role of MSTIDs and sporadic E in the creation of the F-region FAIs.

One-Dimensional Full Wave Simulation of Equatorial Magnetosonic Wave Propagation in an Inhomogeneous Magnetosphere

NASA Astrophysics Data System (ADS)

Liu, Xu; Chen, Lunjin; Yang, Lixia; Xia, Zhiyang; Malaspina, David M.

2018-01-01

The effect of the plasmapause on equatorially radially propagating fast magnetosonic (MS) waves in the Earth's dipole magnetic field is studied by using finite difference time domain method. We run 1-D simulation for three different density profiles: (1) no plasmapause, (2) with a plasmapause, and (3) with a plasmapause accompanied with fine-scale density irregularity. We find that (1) without plasmapause the radially inward propagating MS wave can reach ionosphere and continuously propagate to lower altitude if no damping mechanism is considered. The wave properties follow the cold plasma dispersion relation locally along its trajectory. (2) For simulation with a plasmapause with a scale length of 0.006 RE compared to wavelength, only a small fraction of the MS wave power is reflected by the plasmapause. WKB approximation is generally valid for such plasmapause. (3) The multiple fine-scale density irregularities near the outer edge of plasmapause can effectively block the MS wave propagation, resulting in a terminating boundary for MS waves near the plasmapause.

Initial Results from the Vector Electric Field Investigation on the C/NOFS Satellite

NASA Technical Reports Server (NTRS)

Pfaff, R.; Rowland, D.; Acuna, M.; Le, G.; Farrell, W.; Holzworth, R.; Wilson, G.; Burke, W.; Freudenreich, H.; Bromund, K.;

Plasma Modification of Graphite Fibers and Its Effect on Composite Properties.

DTIC Science & Technology

1983-08-01

liquids have been difficult to measure with adequate accuracy. As a result, critical surface energy data are not readily available. A flotation method...tension of the fiber surface. However, the fiber density must always exceed the density of the flotation liquid. Although this is a very useful...technioue, it is inanplicable to graphite fiber due to its irregular surface structure, small filament diameter and small difference in density with flotation

A Probabilistic Model for Sediment Entrainment: the Role of Bed Irregularity

NASA Astrophysics Data System (ADS)

Thanos Papanicolaou, A. N.

2017-04-01

A generalized probabilistic model is developed in this study to predict sediment entrainment under the incipient motion, rolling, and pickup modes. A novelty of the proposed model is that it incorporates in its formulation the probability density function of the bed shear stress, instead of the near-bed velocity fluctuations, to account for the effects of both flow turbulence and bed surface irregularity on sediment entrainment. The proposed model incorporates in its formulation the collective effects of three parameters describing bed surface irregularity, namely the relative roughness, the volumetric fraction and relative position of sediment particles within the active layer. Another key feature of the model is that it provides a criterion for estimating the lift and drag coefficients jointly based on the recognition that lift and drag forces acting on sediment particles are interdependent and vary with particle protrusion and packing density. The model was validated using laboratory data of both fine and coarse sediment and was compared with previously published models. The study results show that for the fine sediment data, where the sediment particles have more uniform gradation and relative roughness is not a factor, all the examined models perform adequately. The proposed model was particularly suited for the coarse sediment data, where the increased bed irregularity was captured by the new parameters introduced in the model formulations. As a result, the proposed model yielded smaller prediction errors and physically acceptable values for the lift coefficient compared to the other models in case of the coarse sediment data.

Flat epithelial atypia of the breast: pathological-radiological correlation.

PubMed

Solorzano, Silma; Mesurolle, Benoît; Omeroglu, Attila; El Khoury, Mona; Kao, Ellen; Aldis, Ann; Meterissian, Sarkis

2011-09-01

This study was undertaken to determine the prevalence of flat epithelial atypia at ultrasound-guided and stereotactically guided needle biopsies, to describe the mammographic and sonographic features of flat epithelial atypia, and to determine the significance of lesions diagnosed as flat epithelial atypia at imaging-guided needle biopsies. Retrospective review of a database of 1369 consecutive sonographically and stereotactically guided needle biopsies performed during a 12-month period yielded 33 lesions with flat epithelial atypia as the most severe pathologic entity (32 patients). Two radiologists retrospectively reviewed the imaging presentation, by combined consensus, according to the BI-RADS lexicon. Twenty-two of 33 flat epithelial atypia diagnoses (67%) were obtained under stereotactic guidance, and 11 (33%) were obtained under sonographic guidance. Six patients had synchronous breast cancer. Flat epithelial atypia lesions presented mammographically most often as microcalcifications (20/33 [61%]) distributed in a cluster (14/20 [70%]) with amorphous morphology (13/20 [65%]). Sonographically, flat epithelial atypia lesions appeared most often as masses (9/11 [82%]), with an irregular shape (6/9 [67%]), microlobulated margins (5/9 [56%]), and hypoechoic or complex echotexture (7/9 [78%]). Twenty-eight of 33 lesions (85%) were surgically excised, confirming the flat epithelial atypia diagnosis in 11 of the 28 lesions (39%), yielding carcinoma in four (14%) and atypical ductal hyperplasia in six (21%). Columnar cell changes without atypia were diagnosed in four lesions (14%), and lobular carcinoma in situ was diagnosed in three lesions (11%). Mammographic and sonographic presentation of flat epithelial atypia is not specific (clustered amorphous microcalcifications and irregular, hypoechoic or complex masses). Given the underestimation rate of malignancy, surgical excision should be considered when imaging-guided biopsy yields flat epithelial atypia.

Detection limit for rate fluctuations in inhomogeneous Poisson processes

NASA Astrophysics Data System (ADS)

Shintani, Toshiaki; Shinomoto, Shigeru

2012-04-01

Estimations of an underlying rate from data points are inevitably disturbed by the irregular occurrence of events. Proper estimation methods are designed to avoid overfitting by discounting the irregular occurrence of data, and to determine a constant rate from irregular data derived from a constant probability distribution. However, it can occur that rapid or small fluctuations in the underlying density are undetectable when the data are sparse. For an estimation method, the maximum degree of undetectable rate fluctuations is uniquely determined as a phase transition, when considering an infinitely long series of events drawn from a fluctuating density. In this study, we analytically examine an optimized histogram and a Bayesian rate estimator with respect to their detectability of rate fluctuation, and determine whether their detectable-undetectable phase transition points are given by an identical formula defining a degree of fluctuation in an underlying rate. In addition, we numerically examine the variational Bayes hidden Markov model in its detectability of rate fluctuation, and determine whether the numerically obtained transition point is comparable to those of the other two methods. Such consistency among these three principled methods suggests the presence of a theoretical limit for detecting rate fluctuations.

Detection limit for rate fluctuations in inhomogeneous Poisson processes.

PubMed

Shintani, Toshiaki; Shinomoto, Shigeru

2012-04-01

Estimations of an underlying rate from data points are inevitably disturbed by the irregular occurrence of events. Proper estimation methods are designed to avoid overfitting by discounting the irregular occurrence of data, and to determine a constant rate from irregular data derived from a constant probability distribution. However, it can occur that rapid or small fluctuations in the underlying density are undetectable when the data are sparse. For an estimation method, the maximum degree of undetectable rate fluctuations is uniquely determined as a phase transition, when considering an infinitely long series of events drawn from a fluctuating density. In this study, we analytically examine an optimized histogram and a Bayesian rate estimator with respect to their detectability of rate fluctuation, and determine whether their detectable-undetectable phase transition points are given by an identical formula defining a degree of fluctuation in an underlying rate. In addition, we numerically examine the variational Bayes hidden Markov model in its detectability of rate fluctuation, and determine whether the numerically obtained transition point is comparable to those of the other two methods. Such consistency among these three principled methods suggests the presence of a theoretical limit for detecting rate fluctuations.

Rocket in situ observation of equatorial plasma irregularities in the region between E and F layers over Brazil

NASA Astrophysics Data System (ADS)

Savio Odriozola, Siomel; de Meneses, Francisco Carlos, Jr.; Muralikrishna, Polinaya; Alvares Pimenta, Alexandre; Alam Kherani, Esfhan

2017-03-01

A two-stage VS-30 Orion rocket was launched from the equatorial rocket launching station in Alcântara, Brazil, on 8 December 2012 soon after sunset (19:00 LT), carrying a Langmuir probe operating alternately in swept and constant bias modes. At the time of launch, ground equipment operated at equatorial stations showed rapid rise in the base of the F layer, indicating the pre-reversal enhancement of the F region vertical drift and creating ionospheric conditions favorable for the generation of plasma bubbles. Vertical profiles of electron density estimated from Langmuir probe data showed wave patterns and small- and medium-scale plasma irregularities in the valley region (100-300 km) during the rocket upleg and downleg. These irregularities resemble those detected by the very high frequency (VHF) radar installed at Jicamarca and so-called equatorial quasi-periodic echoes. We present evidence suggesting that these observations could be the first detection of this type of irregularity made by instruments onboard a rocket.

Mid-Latitude Disturbances - Triggered by Hurricane Dennis?

NASA Astrophysics Data System (ADS)

Earle, G. D.; Bishop, R. L.

2001-05-01

Midlatitude irregularities in F-region electron density have been previously observed in-situ by the Atmosphere Explorer-E satellite [Hanson and Johnson, 1992]. These authors noted the similarity of the irregularities to equatorial spread-F, which is commonly observed at much lower latitudes (within 20 degrees of the magnetic equator). They coined the term midlatitude disturbances (MLDs), and postulated that the irregularities resulted from the Perkins instability in a region where the east-west velocities of the ions differs from that of the neutrals. We present ionosonde observations of range spread-F made over Wallops Island, VA that may show signatures of similar MLD events. The data show evidence of an apparent correlation between the occurrence of the irregularities and the passage of hurricane Dennis over the magnetic meridian of Wallops Island. Based on this evidence, we examine the possibility that the Perkins instability and/or MLD events can be triggered by gravity waves spawned by the hurricane. Reference: Hanson, W.B., and F.S. Johnson, Planet. Space Sci., vol. 40, pp. 1615-1630, 1992.

Update: The pathogenesis and treatment of PCOS.

PubMed

Hill, Kathryn M

2003-07-01

Irregular menstrual cycles, acne, and hirsutism often cause women to present to a primary care setting. This article demonstrates how to take a careful history, perform a physical examination, and order the laboratory tests necessary to diagnose polycystic ovary syndrome (PCOS). Managing PCOS complaints and maintaining important health issues are also addressed, as well as when to refer to a specialist.

A novel construction scheme of QC-LDPC codes based on the RU algorithm for optical transmission systems

NASA Astrophysics Data System (ADS)

Yuan, Jian-guo; Liang, Meng-qi; Wang, Yong; Lin, Jin-zhao; Pang, Yu

2016-03-01

A novel lower-complexity construction scheme of quasi-cyclic low-density parity-check (QC-LDPC) codes for optical transmission systems is proposed based on the structure of the parity-check matrix for the Richardson-Urbanke (RU) algorithm. Furthermore, a novel irregular QC-LDPC(4 288, 4 020) code with high code-rate of 0.937 is constructed by this novel construction scheme. The simulation analyses show that the net coding gain ( NCG) of the novel irregular QC-LDPC(4 288,4 020) code is respectively 2.08 dB, 1.25 dB and 0.29 dB more than those of the classic RS(255, 239) code, the LDPC(32 640, 30 592) code and the irregular QC-LDPC(3 843, 3 603) code at the bit error rate ( BER) of 10-6. The irregular QC-LDPC(4 288, 4 020) code has the lower encoding/decoding complexity compared with the LDPC(32 640, 30 592) code and the irregular QC-LDPC(3 843, 3 603) code. The proposed novel QC-LDPC(4 288, 4 020) code can be more suitable for the increasing development requirements of high-speed optical transmission systems.

Multi-instrumental Analysis of the Ionospheric Density Response to Geomagnetic Disturbances

NASA Astrophysics Data System (ADS)

Zakharenkova, I.; Astafyeva, E.

2014-12-01

Measurements provided by Low Earth Orbit (LEO) satellite missions have already proved to be very efficient in investigations of global redistribution of ionospheric plasma and thermosphere mass density during such phenomena as geomagnetic storms. LEO satellites have various instruments for research of the ionosphere response to the space weather events like GPS receiver for precise orbit determination (POD), total electron content estimation and radio occultation, altimeter, planar Langmuir probe, topside sounder, special detectors for particle fluxes, magnetometer etc. In this paper, we present results of joint analysis of LEO satellite data, in particular CHAMP, DMSP, JASON, as well as data provided by ground-based networks of GPS receivers and ionosonde stations for global ionospheric response to the geomagnetic disturbances. We use in-situ plasma density data from CHAMP and DMSP satellites, along with data of GPS receiver onboard CHAMP-satellite and ground-based GPS-receivers to study occurrence and global distribution of ionospheric irregularities during the main phase of the storm. Using CHAMP GPS measurements, we created maps of GPS phase fluctuation activity and found two specific zones of the most intense irregularities - first is the region of the auroral oval at high latitudes of both hemispheres, the second one is the low-latitudes/equatorial region between Africa and South America. The interhemispheric asymmetry of the ionospheric irregularities intensity and occurrence in polar region is discussed. Analysis of the topside TEC, derived from CHAMP onboard GPS POD antenna, indicate the significant redistribution of the topside ionospheric plasma density in the equatorial, middle and high-latitude ionosphere during main and recovery phases of geomagnetic storm. Multi-instrumental data allow to analyze in detail the complex modification and dynamics of the upper atmosphere in different altitudinal, spatial and temporal scales.

Observations of the electron density perturbation in the cusp irregularities during the ICI-2 campaign

NASA Astrophysics Data System (ADS)

Abe, Takumi; Moen, J. I.

The ICI-2 (Investigation of Cusp Irregularities-2) sounding rocket campaign was conducted in Svalbard, Norway on December 2008. The scientific objective of ICI-2 is to investigate genera-tion mechanism(s) of coherent HF radar backscatter targets. Strong coherent HF backscatter echoes are well-known phenomena in the polar ionospheric cusp, and are thought to result from field-aligned plasma irregularities with decameter scale length. However, the generation mech-anism of backscatter targets has not yet been understood, and even the altitude profile of HF cusp backscatter is unknown. The ICI-2 rocket was launched at 10:35:10 UT at Ny-˚lesund, A and reached an apogee of 330 km at about 5 minutes after the launch. All onboard systems functioned flawlessly. A comprehensive measurement of the electron density, low energy elec-tron flux, medium energy particle flux, AC and DC electric fields was conducted to exploit the potential role of the gradient drift instability versus the other suggested mechanisms. We present a result obtained from a Fixed-Biased Probe (FBP) which was aimed at measuring fine-scale (< 1 m) electron density perturbation. Our analysis of the FBP data during the rocket's flight indicates that the rocket traversed HF backscatter regions where the electron density perturbation is relatively large. The power spectrum analysis of the electron density shows that the amplitude increases not only in the decameter wavelength but also in the broad range of frequency. Characteristic features of the electron density perturbation are summarized as follows: 1) A strong perturbation of the electron density was observed by the FBP when the ICI-2 rocket passed through a front side of the poleward moving 630 nm emission region which was identified by the all-sky imager. This means that the electron density perturbation and the 630 nm emission are observed to coexist in the same region. 2) The absolute value of the electron density becomes larger in the disturbed region than in the surrounding region. The electron density gradient in the boundary with the outer region is larger in the equatorward side than in the poleward side. 3) The amplitude of the electron density perturbation is remarkably large in the equatorward edge rather than the poleward boundaries. 4) The FBP identified the electron density perturbation at three different altitudes during the rocket flight. This indicates that the perturbation likely exists not only within the narrow limits but in a larger extent in the vertical direction.

Use of a spread sheet to calculate the current-density distribution produced in human and rat models by low-frequency electric fields.

PubMed

Hart, F X

1990-01-01

The current-density distribution produced inside irregularly shaped, homogeneous human and rat models by low-frequency electric fields is obtained by a two-stage finite-difference procedure. In the first stage the model is assumed to be equipotential. Laplace's equation is solved by iteration in the external region to obtain the capacitive-current densities at the model's surface elements. These values then provide the boundary conditions for the second-stage relaxation solution, which yields the internal current-density distribution. Calculations were performed with the Excel spread-sheet program on a Macintosh-II microcomputer. A spread sheet is a two-dimensional array of cells. Each cell of the sheet can represent a square element of space. Equations relating the values of the cells can represent the relationships between the potentials in the corresponding spatial elements. Extension to three dimensions is readily made. Good agreement was obtained with current densities measured on human models with both, one, or no legs grounded and on rat models in four different grounding configurations. The results also compared well with predictions of more sophisticated numerical analyses. Spread sheets can provide an inexpensive and relatively simple means to perform good, approximate dosimetric calculations on irregularly shaped objects.

ON THE STAR FORMATION LAW FOR SPIRAL AND IRREGULAR GALAXIES

DOE Office of Scientific and Technical Information (OSTI.GOV)

Elmegreen, Bruce G., E-mail: bge@us.ibm.com

2015-12-01

A dynamical model for star formation on a galactic scale is proposed in which the interstellar medium is constantly condensing to star-forming clouds on the dynamical time of the average midplane density, and the clouds are constantly being disrupted on the dynamical timescale appropriate for their higher density. In this model, the areal star formation rate scales with the 1.5 power of the total gas column density throughout the main regions of spiral galaxies, and with a steeper power, 2, in the far outer regions and in dwarf irregular galaxies because of the flaring disks. At the same time, theremore » is a molecular star formation law that is linear in the main and outer parts of disks and in dIrrs because the duration of individual structures in the molecular phase is also the dynamical timescale, canceling the additional 0.5 power of surface density. The total gas consumption time scales directly with the midplane dynamical time, quenching star formation in the inner regions if there is no accretion, and sustaining star formation for ∼100 Gyr or more in the outer regions with no qualitative change in gas stability or molecular cloud properties. The ULIRG track follows from high densities in galaxy collisions.« less

A decametric wavelength radio telescope for interplanetary scintillation observations

NASA Technical Reports Server (NTRS)

Cronyn, W. M.; Shawhan, S. D.

1975-01-01

A phased array, electrically steerable radio telescope (with a total collecting area of 18 acres), constructed for the purpose of remotely sensing electron density irregularity structure in the solar wind, is presented. The radio telescope is able to locate, map, and track large scale features of the solar wind, such as streams and blast waves, by monitoring a large grid of natural radio sources subject to rapid intensity fluctuation (interplanetary scintillation) caused by the irregularity structure. Observations verify the performance of the array, the receiver, and the scintillation signal processing circuitry of the telescope.

Rocket experiments for spectral estimation of electron density fine structure in the auroral and equatorial ionosphere and preliminary results

NASA Technical Reports Server (NTRS)

Tomei, B. A.; Smith, L. G.

1986-01-01

Sounding rockets equipped to monitor electron density and its fine structure were launched into the auroral and equatorial ionosphere in 1980 and 1983, respectively. The measurement electronics are based on the Langmuir probe and are described in detail. An approach to the spectral analysis of the density irregularities is addressed and a software algorithm implementing the approach is given. Preliminary results of the analysis are presented.

Phonological Codes Constrain Output of Orthographic Codes via Sublexical and Lexical Routes in Chinese Written Production

PubMed Central

Wang, Cheng; Zhang, Qingfang

2015-01-01

To what extent do phonological codes constrain orthographic output in handwritten production? We investigated how phonological codes constrain the selection of orthographic codes via sublexical and lexical routes in Chinese written production. Participants wrote down picture names in a picture-naming task in Experiment 1or response words in a symbol—word associative writing task in Experiment 2. A sublexical phonological property of picture names (phonetic regularity: regular vs. irregular) in Experiment 1and a lexical phonological property of response words (homophone density: dense vs. sparse) in Experiment 2, as well as word frequency of the targets in both experiments, were manipulated. A facilitatory effect of word frequency was found in both experiments, in which words with high frequency were produced faster than those with low frequency. More importantly, we observed an inhibitory phonetic regularity effect, in which low-frequency picture names with regular first characters were slower to write than those with irregular ones, and an inhibitory homophone density effect, in which characters with dense homophone density were produced more slowly than those with sparse homophone density. Results suggested that phonological codes constrained handwritten production via lexical and sublexical routes. PMID:25879662

The correlation function for density perturbations in an expanding universe. I - Linear theory

NASA Technical Reports Server (NTRS)

Mcclelland, J.; Silk, J.

1977-01-01

The evolution of the two-point correlation function for adiabatic density perturbations in the early universe is studied. Analytical solutions are obtained for the evolution of linearized spherically symmetric adiabatic density perturbations and the two-point correlation function for these perturbations in the radiation-dominated portion of the early universe. The results are then extended to the regime after decoupling. It is found that: (1) adiabatic spherically symmetric perturbations comparable in scale with the maximum Jeans length would survive the radiation-dominated regime; (2) irregular fluctuations are smoothed out up to the scale of the maximum Jeans length in the radiation era, but regular fluctuations might survive on smaller scales; (3) in general, the only surviving structures for irregularly shaped adiabatic density perturbations of arbitrary but finite scale in the radiation regime are the size of or larger than the maximum Jeans length in that regime; (4) infinite plane waves with a wavelength smaller than the maximum Jeans length but larger than the critical dissipative damping scale could survive the radiation regime; and (5) black holes would also survive the radiation regime and might accrete sufficient mass after decoupling to nucleate the formation of galaxies.

Effects of corneal irregular astigmatism on visual acuity after conventional and femtosecond laser-assisted Descemet's stripping automated endothelial keratoplasty.

PubMed

Tomida, Daisuke; Yamaguchi, Takefumi; Ogawa, Akiko; Hirayama, Yumiko; Shimazaki-Den, Seika; Satake, Yoshiyuki; Shimazaki, Jun

2015-07-01

To compare short-term outcomes of Descemet's stripping automated endothelial keratoplasty (DSAEK) using a graft prepared with either a femtosecond laser or a microkeratome. Thirty-eight patients underwent DSAEK with grafts prepared with either a femtosecond laser (f-DSAEK; 21 eyes) or a microkeratome (m-DSAEK; 17 eyes). Visual acuity, endothelial cell density, regular astigmatism and irregular astigmatism were compared between the two groups preoperatively and at 1, 3, and 6 months post-operatively. Fourier analysis was conducted to calculate astigmatism of the anterior and posterior surfaces, and total cornea, using anterior segment optical coherence tomography (AS-OCT). Visual acuity (logMAR) improved from 1.20 ± 0.60 to 0.43 ± 0.25 after m-DSAEK (P < 0.001) and from 1.20 ± 0.57 to 0.77 ± 0.33 after f-DSAEK (P = 0.0028) at 6 months following DSAEK. Visual acuity after m-DSAEK was significantly better than after f-DSAEK at 1, 3, and 6 months (P < 0.05). AS-OCT corneal images revealed greater irregularities on the posterior surfaces of f-DSAEK grafts compared to m-DSAEK grafts. Irregular astigmatism of the total cornea and the posterior surface was significantly larger after f-DSAEK than after m-DSAEK, although there was no significant difference in irregular astigmatism of the anterior surface at 6 months. Postoperative visual acuity was significantly correlated with the postoperative irregular astigmatism of the total cornea (r = 0.6657 and P < 0.001) and the anterior (r = 0.416, P = 0.016) and posterior surfaces (r = 0.7046, P < 0.001). Visual outcomes after f-DSAEK were poor compared to conventional m-DSAEK due to an increase in irregular astigmatism caused by posterior surface irregularities.

CT diagnosis and differentiation of benign and malignant varieties of solitary fibrous tumor of the pleura

PubMed Central

You, Xiaofang; Sun, Xiwen; Yang, Chunyan; Fang, Yong

2017-01-01

Abstract To investigate computed tomography (CT) characteristics of benign and malignant solitary fibrous tumors of the pleura (SFTPs). Preoperative CTs for 60 SFTP cases (49 benign and 11 malignant) with subsequently confirmed diagnoses were retrospectively analyzed. Tumor morphologies included mounded or mushroom umbrella-shape (19 cases, 31.7%), quasi-circular or oval-shape (30 cases, 50%), and growth resembling a casting mould (12 cases, 20%). Maximum tumor diameters were 1.1 to 18.9 cm (average: 6.4 ± 4.8 cm). Fifty-seven cases had clear boundaries, and 3 had partially coarse boundaries. Twenty-seven cases showed homogeneous density; 33, “geographic”-patterned inhomogeneous density; 6, calcifications; 12, intratumor blood vessels; and 3, thick nourishing peritumoral blood vessels. Pleural thickening (regular and irregular) was found adjacent to tumors in 4, compression of adjacent ribs with absorption and cortical sclerosis in 2, and location adjacent to ribs with bony destruction in 1. Four cases had a small amount of lung tissue enfolded along the boundary, 2 had multiple peritumoral pulmonary bullae, and 9 had small ipsilateral pleural effusions. Compared with benign and malignant SFTPs were larger (P < .001), had inhomogeneous density, and were more commonly associated with intratumor blood vessels and pleural effusions (P < .01). CT revealed characteristic patterns in SFTPs, including casting mould-like growth, rich blood supply, and “geographic”-patterned enhancement. In addition, larger tumor size, inhomogeneous intensities, abundant intratumor blood vessels, and pleural effusions were more common with malignancy. Lastly, multislice CT angiography can reveal feeding arteries and help guide surgical management. PMID:29245313

CT diagnosis and differentiation of benign and malignant varieties of solitary fibrous tumor of the pleura.

PubMed

You, Xiaofang; Sun, Xiwen; Yang, Chunyan; Fang, Yong

2017-12-01

To investigate computed tomography (CT) characteristics of benign and malignant solitary fibrous tumors of the pleura (SFTPs).Preoperative CTs for 60 SFTP cases (49 benign and 11 malignant) with subsequently confirmed diagnoses were retrospectively analyzed.Tumor morphologies included mounded or mushroom umbrella-shape (19 cases, 31.7%), quasi-circular or oval-shape (30 cases, 50%), and growth resembling a casting mould (12 cases, 20%). Maximum tumor diameters were 1.1 to 18.9 cm (average: 6.4 ± 4.8 cm). Fifty-seven cases had clear boundaries, and 3 had partially coarse boundaries. Twenty-seven cases showed homogeneous density; 33, "geographic"-patterned inhomogeneous density; 6, calcifications; 12, intratumor blood vessels; and 3, thick nourishing peritumoral blood vessels. Pleural thickening (regular and irregular) was found adjacent to tumors in 4, compression of adjacent ribs with absorption and cortical sclerosis in 2, and location adjacent to ribs with bony destruction in 1. Four cases had a small amount of lung tissue enfolded along the boundary, 2 had multiple peritumoral pulmonary bullae, and 9 had small ipsilateral pleural effusions. Compared with benign and malignant SFTPs were larger (P < .001), had inhomogeneous density, and were more commonly associated with intratumor blood vessels and pleural effusions (P < .01).CT revealed characteristic patterns in SFTPs, including casting mould-like growth, rich blood supply, and "geographic"-patterned enhancement. In addition, larger tumor size, inhomogeneous intensities, abundant intratumor blood vessels, and pleural effusions were more common with malignancy. Lastly, multislice CT angiography can reveal feeding arteries and help guide surgical management.

PROBLEM ON IRREGULAR 3-DIMENSIONAL DENSITY DISCONTINUITY SURFACES.

DTIC Science & Technology

method. The result is used to analyze the relation of linear correlation between the crustal thickness and the local Bouguer gravity anomaly, and good agreement is obtained in comparison with the actual statistical data. (Author)

Menstrual Dysfunction in Girls from the Treatment Options for Type 2 Diabetes in Adolescents and Youth (TODAY) Study.

PubMed

Kelsey, Megan M; Braffett, Barbara H; Geffner, Mitchell E; Levitsky, Lynne L; Caprio, Sonia; McKay, Siripoom V; Shah, Rachana; Sprague, Jennifer E; Arslanian, Silva A

2018-04-24

Little is known about reproductive function in girls with youth-onset type 2 diabetes. To characterize girls with irregular menses, and effects of glycemic treatments on menses and sex steroids in the Treatment Options for Type 2 Diabetes in Youth (TODAY) study. Differences in demographic, metabolic, and hormonal characteristics between regular vs. irregular menses groups were tested; treatment group (metformin +/- rosiglitazone, metformin + lifestyle) effect on menses and sex steroids over time in the study was assessed. This is a secondary analysis of TODAY data. Multi-center study in an academic setting. TODAY girls not on hormonal contraception and those > 1-year post-menarche were included. Irregular menses was defined as < 3 periods in the prior 6 months. Eligible participants with serum measurement of sex steroids (n=190, mean age 14 years), 21% had irregular menses. Those with irregular vs. regular menses had higher body mass index (BMI) (p=0.001), AST (p=0.001), free androgen index (p=0.0003), total testosterone (p=0.01); and lower sex-hormone binding globulin (SHBG) (p=0.004) and estradiol (p=0.01). Differences remained after adjusting for BMI. There was no treatment group effect on menses or sex steroids at 12 or 24 months, and no association of sex steroids with measures of insulin sensitivity or secretion. Menstrual dysfunction is common in girls with recently diagnosed T2D and associated with alterations in sex steroids, SHBG, and AST, but not with alteration in insulin sensitivity or β-cell function, and did not improve with 2 years of anti-hyperglycemic treatment.

Volume Quantification of Acute Infratentorial Hemorrhage with Computed Tomography: Validation of the Formula 1/2ABC and 2/3SH

PubMed Central

Zhang, Yunyun; Yan, Jing; Fu, Yi; Chen, Shengdi

2013-01-01

Objective To compare the accuracy of formula 1/2ABC with 2/3SH on volume estimation for hypertensive infratentorial hematoma. Methods One hundred and forty-seven CT scans diagnosed as hypertensive infratentorial hemorrhage were reviewed. Based on the shape, hematomas were categorized as regular or irregular. Multilobular was defined as a special shape of irregular. Hematoma volume was calculated employing computer-assisted volumetric analysis (CAVA), 1/2ABC and 2/3SH, respectively. Results The correlation coefficients between 1/2ABC (or 2/3SH) and CAVA were greater than 0.900 in all subgroups. There were neither significant differences in absolute values of volume deviation nor percentage deviation between 1/2ABC and 2/3SH for regular hemorrhage (P>0.05). While for cerebellar, brainstem and irregular hemorrhages, the absolute values of volume deviation and percentage deviation by formula 1/2ABC were greater than 2/3SH (P<0.05). 1/2ABC and 2/3SH underestimated hematoma volume each by 10% and 5% for cerebellar hemorrhage, 14% and 9% for brainstem hemorrhage, 19% and 16% for regular hemorrhage, 9% and 3% for irregular hemorrhage, respectively. In addition, for the multilobular hemorrhage, 1/2ABC underestimated the volume by 9% while 2/3SH overestimated it by 2%. Conclusions For regular hemorrhage volume calculation, the accuracy of 2/3SH is similar to 1/2ABC. While for cerebellar, brainstem or irregular hemorrhages (including multilobular), 2/3SH is more accurate than 1/2ABC. PMID:23638025

Utility of contrast-enhanced harmonic EUS in the diagnosis of malignant gallbladder polyps (with videos).

PubMed

Choi, Jun-Ho; Seo, Dong-Wan; Choi, Joon Hyuk; Park, Do Hyun; Lee, Sang Soo; Lee, Sung Koo; Kim, Myung-Hwan

2013-09-01

The differential diagnosis between benign and malignant polyps of the gallbladder (GB) is often challenging. To evaluate whether contrast-enhanced harmonic EUS (CEH-EUS) might be an accurate method for discriminating malignant GB polyps from benign polyps. Observational study. Tertiary care medical center. Ninety-three patients with GB polyps larger than 10 mm in diameter that were detected by conventional EUS underwent CEH-EUS for evaluation of microvasculature. CEH-EUS was performed using a radial echoendoscope and the extended pure harmonic detection mode. The abilities of conventional EUS and CEH-EUS to diagnose malignant polyp were compared. Two blinded reviewers classified the perfusion images into 3 categories: diffuse enhancement, perfusion defect, or nonenhancement. The vessel images were categorized as having a regular spotty vessel, an irregular vessel, or no vessels. An irregular vessel pattern determined by CEH-EUS aided in the diagnosis of malignant polyps with a sensitivity and specificity of 90.3% and 96.6%, respectively. The presence of perfusion defects, determined by CEH-EUS, was calculated to diagnose malignant polyps with a sensitivity and specificity of 90.3% and 94.9%, respectively. Based on the definitely determined diagnosis, sensitivity and specificity for CEH-EUS were 93.5% and 93.2% versus 90.0% and 91.1% for conventional EUS. In 8 cases, management changed after CEH-EUS. A tertiary medical center with a limited number of patients. The presence of irregular intratumoral vessels or perfusion defects seen on CEH-EUS may be sensitive and accurate predictors of malignant GB polyps. CEH-EUS offers slightly improved diagnostic accuracy compared with EUS. Copyright © 2013 American Society for Gastrointestinal Endoscopy. All rights reserved.

Characterizing the 10 November 2004 storm-time middle-latitude plasma bubble event in Southeast Asia using multi-instrument observations

NASA Astrophysics Data System (ADS)

Li, Guozhu; Ning, Baiqi; Zhao, Biqiang; Liu, Libo; Wan, Weixing; Ding, Feng; Xu, J. S.; Liu, J. Y.; Yumoto, K.

2009-07-01

The development and dynamics of ionospheric plasma bubble (PB) irregularity during the super storm of 7-11 November 2004 are investigated using the data from a multi-instrument network operated in Southeast Asia. Analysis of fluctuations in Global Positioning System total electron content (GPS TEC), ionosonde, GPS scintillation, and in situ satellite density data indicates a series of intense PB-associated irregularities at equatorial, low, and middle latitudes in the Japanese longitude on 10 November. However, in the Chinese sector, the scintillations and PB irregularities are confined within the range of 20-50°N in geographic latitude and 110-125°E in geographic longitude. The absence of equatorial PB irregularities in this sector shows a major difference from that in the close-by longitude Japanese sector. In the Southern Hemisphere Australian sector, the irregularities occurrence is present as a symmetrical distribution at conjugate latitudes. Combined analysis of the data from Osan and Wuhan ionosondes illustrates that the middle-latitude spread F irregularities initially develop at the lower part of the F region and then distribute in the whole F region. This initiation of spread F at lower altitudes indicates that the middle-latitude PB-associated irregularities are locally generated. These results together with the irregularities occurrence sequence from higher to lower latitudes, and the onset time delay of several hours implies that the presence of PB-associated irregularities within a latitude range of 20-50°N in the Chinese sector cannot be attributed to the effects of prompt penetration electric fields (PPEFs), although the equatorial PBs in the close-by longitude are seen to be associated with PPEFs. The possible mechanism is the F region plasma instabilities triggered by wave structures, which act as an external driving force and seed active plasma dynamics and instability growth at middle latitude.

Low-density parity-check codes for volume holographic memory systems.

PubMed

Pishro-Nik, Hossein; Rahnavard, Nazanin; Ha, Jeongseok; Fekri, Faramarz; Adibi, Ali

2003-02-10

We investigate the application of low-density parity-check (LDPC) codes in volume holographic memory (VHM) systems. We show that a carefully designed irregular LDPC code has a very good performance in VHM systems. We optimize high-rate LDPC codes for the nonuniform error pattern in holographic memories to reduce the bit error rate extensively. The prior knowledge of noise distribution is used for designing as well as decoding the LDPC codes. We show that these codes have a superior performance to that of Reed-Solomon (RS) codes and regular LDPC counterparts. Our simulation shows that we can increase the maximum storage capacity of holographic memories by more than 50 percent if we use irregular LDPC codes with soft-decision decoding instead of conventionally employed RS codes with hard-decision decoding. The performance of these LDPC codes is close to the information theoretic capacity.

Ultrasonographic findings of shoulder teno-muscular structures in symptomatic and asymptomatic dogs.

PubMed

Barella, Gabriele; Lodi, Matteo; Faverzani, Stefano

2017-11-14

B-mode sonographic evaluation of shoulder joint in dogs provides qualitative information concerning mainly tendon and muscles structures. Although the sonographic findings of tenomuscular lesions have been described previously, their frequency in symptomatic and asymptomatic patients has not been reported yet. Aim of the study was to describe and compare qualitative ultrasonographic findings of shoulder joint in clinically symptomatic and asymptomatic dogs and to speculate which lesions might be considered major responsible for lameness. Fifty-two dogs with shoulder lameness and 58 asymptomatic dogs (both with unremarkable radiographic findings) underwent ultrasonographic B-mode examination of the scapulohumeral joint. Lesions detected were recorded and statistically compared between groups. Significant differences between groups were observed for the number of ultrasonographic abnormalities detected and for fluid accumulation, biceps brachii tendon (BT) lesions and bone surface irregularities. Sonography was considered useful for the determination of lesions absence and for the detection of BT lesions, fluid accumulation, muscle lacerations and bone surface irregularities. The odds for symptomatic dogs were greater than for asymptomatic patients to ultrasonographically diagnose BT lesions, fluid accumulation and bone surface irregularities. Ultrasound has proven to be a useful tool in the evaluation of tenomusculoskeletal structures of shoulder in dogs with unremarkable radiographic findings. Our results suggest that ultrasonography is useful in the diagnosis of tendon abnormalities, fluid accumulation, muscle lacerations and bone surface irregularities as potential contributors to shoulder lameness in dogs.

High-amplitude fluctuations and alternative dynamical states of midges in Lake Myvatn.

PubMed

Ives, Anthony R; Einarsson, Arni; Jansen, Vincent A A; Gardarsson, Arnthor

2008-03-06

Complex dynamics are often shown by simple ecological models and have been clearly demonstrated in laboratory and natural systems. Yet many classes of theoretically possible dynamics are still poorly documented in nature. Here we study long-term time-series data of a midge, Tanytarsus gracilentus (Diptera: Chironomidae), in Lake Myvatn, Iceland. The midge undergoes density fluctuations of almost six orders of magnitude. Rather than regular cycles, however, these fluctuations have irregular periods of 4-7 years, indicating complex dynamics. We fit three consumer-resource models capable of qualitatively distinct dynamics to the data. Of these, the best-fitting model shows alternative dynamical states in the absence of environmental variability; depending on the initial midge densities, the model shows either fluctuations around a fixed point or high-amplitude cycles. This explains the observed complex population dynamics: high-amplitude but irregular fluctuations occur because stochastic variability causes the dynamics to switch between domains of attraction to the alternative states. In the model, the amplitude of fluctuations depends strongly on minute resource subsidies into the midge habitat. These resource subsidies may be sensitive to human-caused changes in the hydrology of the lake, with human impacts such as dredging leading to higher-amplitude fluctuations. Tanytarsus gracilentus is a key component of the Myvatn ecosystem, representing two-thirds of the secondary productivity of the lake and providing vital food resources to fish and to breeding bird populations. Therefore the high-amplitude, irregular fluctuations in midge densities generated by alternative dynamical states dominate much of the ecology of the lake.

Microwave emission and scattering from Earth surface and atmosphere

NASA Technical Reports Server (NTRS)

Kong, J. A.; Lee, M. C.

1986-01-01

Nonlinear Electromagnetic (EM) wave interactions with the upper atmosphere were investigated during the period 15 December 1985 to 15 June 1986. Topics discussed include: the simultaneous excitation of ionospheric density irregularities and Earth's magnetic field fluctuations; the electron acceleration by Langmuir wave turbulence; and the occurrence of artificial spread F. The role of thermal effects in generating ionospheric irregularities by Whistler waves, intense Quasi-DC electric fields, atmospheric gravity waves, and electrojets was investigated. A model was developed to explain the discrete spectrum of the resonant ultralow frequency (ULF) waves that are commonly observed in the magnetosphere.

Ethinylestradiol/Chlormadinone acetate for use in dermatological disorders.

PubMed

Gómez Vázquez, Mercedes; Navarra Amayuelas, Ramón; Lamarca, Marta; Baquedano, Laura; Romero Ruiz, Sebastián; Vilar-Checa, Eduardo; Iniesta, Maria D

2011-09-06

The diagnosis and management of four cases of dermatological disorders, most of which are related to the endocrine disorder of androgen excess, are presented. Combined oral contraceptives (COCs) may be useful when well-tolerated hormonal therapy and/or when contraception is required. A female patient with androgenetic alopecia or female pattern balding, without underlying hyperandrogenism, was treated with ethinylestradiol/chlormadinone acetate (EE/CMA) 0.03 mg/2 mg for 6 months and experienced stabilization of hair loss (case report 1). A patient who had previously received a COC for an irregular menstrual pattern but again experienced irregular menses and also acne after stopping treatment was diagnosed with acne associated with polycystic ovary syndrome (PCOS) [case report 2]. After 6 month's treatment with EE/CMA 0.03 mg/2 mg, this patient had fewer acne lesions and became eumenorrheic. A third patient who had excess hair since childhood was diagnosed with idiopathic hirsutism (no underlying gynecological or endocrinological disorder was found) and was treated with EE/CMA 0.03 mg/2 mg (case report 3). Less hair growth was reported after 6 months' treatment. Case report 4 describes a patient who presented with oligomenorrhea and acne. She was diagnosed with PCOS with acne, seborrhea and mild hirsutism. Treatment with EE/CMA 0.03 mg/2 mg for 6 months resulted in improvements in her facial acne, seborrhea and hirsutism; she also became eumenorrheic. These four cases illustrate that EE/CMA may be a useful and well tolerated treatment option in the management of patients with dermatological disorders with or without hyperandrogenization.

A Comparison of Young Star Properties with Local Galactic Environment for LEGUS/LITTLE THINGS Dwarf Irregular Galaxies

NASA Astrophysics Data System (ADS)

Hunter, Deidre A.; Adamo, Angela; Elmegreen, Bruce G.; Gallardo, Samavarti; Lee, Janice C.; Cook, David O.; Thilker, David; Kayitesi, Bridget; Kim, Hwihyun; Kahre, Lauren; Ubeda, Leonardo; Bright, Stacey N.; Ryon, Jenna E.; Calzetti, Daniela; Tosi, Monica; Grasha, Kathryn; Messa, Matteo; Fumagalli, Michele; Dale, Daniel A.; Sabbi, Elena; Cignoni, Michele; Smith, Linda J.; Gouliermis, Dimitrios M.; Grebel, Eva K.; Aloisi, Alessandra; Whitmore, Bradley C.; Chandar, Rupali; Johnson, Kelsey E.

2018-07-01

We have explored the role environmental factors play in determining characteristics of young stellar objects in nearby dwarf irregular and blue compact dwarf galaxies. Star clusters are characterized by concentrations, masses, and formation rates; OB associations by mass and mass surface density; O stars by their numbers and near-ultraviolet absolute magnitudes; and H II regions by Hα surface brightnesses. These characteristics are compared to surrounding galactic pressure, stellar mass density, H I surface density, and star formation rate (SFR) surface density. We find no trend of cluster characteristics with environmental properties, implying that larger-scale effects are more important in determining cluster characteristics or that rapid dynamical evolution erases any memory of the initial conditions. On the other hand, the most massive OB associations are found at higher pressure and H I surface density, and there is a trend of higher H II region Hα surface brightness with higher pressure, suggesting that a higher concentration of massive stars and gas is found preferentially in regions of higher pressure. At low pressures we find massive stars but not bound clusters and OB associations. We do not find evidence for an increase of cluster formation efficiency as a function of SFR density. However, there is an increase in the ratio of the number of clusters to the number of O stars with increasing pressure, perhaps reflecting an increase in clustering properties with SFR.

Subareolar breast abscess in male patients: a report of two patients with a literature review.

PubMed

Kazama, Takashi; Tabei, Isao; Sekine, Chikako; Funamizu, Naotake; Onda, Shinji; Okamoto, Tomoyoshi; Takeyama, Hiroshi; Morikawa, Toshiaki

2017-12-19

Subareolar breast abscess (SBA) is a rare infectious disease of the breast in male patients. Herein, we report two male patients with SBA. Patient 1 was initially diagnosed with a malignant tumor based on imaging findings; ultrasonography revealed a hypoechoic mass with blood flow. Patient 2 was diagnosed with inflammatory changes to his nipple; ultrasonography findings supported the diagnosis with an irregular hypoechoic mass with blood flow. Both patients received a cytological or histological biopsy preoperatively, which showed an abscess without malignant cells. These cases serve as an important reminder to consider complete resection of the tumor including the responsible mammary duct (tumor and duct resection (TDR)) for curative therapy of SBA.

Space Weather Effects on the Dynamics of Equatorial F Region Irregularities

NASA Astrophysics Data System (ADS)

Bhattacharyya, A.; Basu, S.; Groves, K.; Valladares, C.; Sheehan, R.

Space weather effects on transionospheric radio waves used for navigation and communication may be divided into two categories depending on the spatial scale size of the ionospheric perturbation produced by such effects. For large-scale (> 10 km) perturbations in the ionospheric plasma density, there are changes in the excess time delay for a radio wave signal, which propagates through the ionosphere, while small scale (< 1 m) structures or irregularities in the ionosphere may give rise tok amplitude and phase scintillations on UHF/L-band radio waves, resulting in loss of data, cycle slips and loss of phase lock for signals used in communication/navigation systems. In the equatorial region, where such effects may be severe, space weather effects on the dynamics of equatorial spread F (ESF) irregularities are studied from two different angles. The first one deals with the effect of magnetic activity on the generation of ESF irregularities by helping or hindering the growth of the Rayleigh Taylor (R-T) instability in the post-sunset equatorial F region. For this purpose, spaced receiver observations of scintillations on a UHF signal transmitted from a geostationary satellite and recorded near the dip equator, are used to establish the `age' of the irregularities. This is necessary because the occurrence of scintillations, particularly in the post midnight period, may also be due to irregularities which drift into the path of the radio wave signal, after having been generated more than 3 hours before the actual observation of scintillations. In order to associate the generation of irregularities with major changes in space weather, a parameter that is a measure of random variations in irregularity drift speed is computed from spaced receiver scintillation data. A large value of this parameter is usually a signature of random variations in irregularity drift due to polarization electric fields associated with freshly generated irregularities. Once these electric fields decay, the irregularities drift with the background plasma. This allows a study of the other effect of space weather on the dynamics of equatorial F region irregularities, viz. magnetically disturbed ionospheric drifts in the equatorial region. The drifts estimated for magnetically quiet days with ESF, within a period of a month, display far less variability than the quiet time variability for non-ESF days, thus making it possible to quantify perturbations in irregularity drift due to disturbance dynamo electric fields and/or prompt penetration of transient magnetospheric electric fields.

The Nature of Turbulence in the LITTLE THINGS Dwarf Irregular Galaxies

DOE Office of Scientific and Technical Information (OSTI.GOV)

Maier, Erin; Chien, Li-Hsin; Hollyday, Gigja

We present probability density functions and higher order (skewness and kurtosis) analyses of the galaxy-wide and spatially resolved distributions of H i column density in the LITTLE THINGS sample of dwarf irregular galaxies. This analysis follows that of Burkhart et al. for the Small Magellanic Cloud (SMC). About 60% of our sample have galaxy-wide values of kurtosis that are similar to that found for the SMC, with a range up to much higher values, and kurtosis increases with integrated star formation rate. Kurtosis and skewness were calculated for radial annuli and for a grid of 32 pixel × 32 pixel kernels acrossmore » each galaxy. For most galaxies, kurtosis correlates with skewness. For about half of the galaxies, there is a trend of increasing kurtosis with radius. The range of kurtosis and skewness values is modeled by small variations in the Mach number close to the sonic limit and by conversion of H i to molecules at high column density. The maximum H i column densities decrease with increasing radius in a way that suggests molecules are forming in the weak-field limit, where H{sub 2} formation balances photodissociation in optically thin gas at the edges of clouds.« less

Retrospective Methods Analysis of Semiautomated Intracerebral Hemorrhage Volume Quantification From a Selection of the STICH II Cohort (Early Surgery Versus Initial Conservative Treatment in Patients With Spontaneous Supratentorial Lobar Intracerebral Haematomas).

PubMed

Haley, Mark D; Gregson, Barbara A; Mould, W Andrew; Hanley, Daniel F; Mendelow, Alexander David

2018-02-01

The ABC/2 method for calculating intracerebral hemorrhage (ICH) volume has been well validated. However, the formula, derived from the volume of an ellipse, assumes the shape of ICH is elliptical. We sought to compare the agreement of the ABC/2 formula with other methods through retrospective analysis of a selection of the STICH II cohort (Early Surgery Versus Initial Conservative Treatment in Patients With Spontaneous Supratentorial Lobar Intracerebral Haematomas). From 390 patients, 739 scans were selected from the STICH II image archive based on the availability of a CT scan compatible with OsiriX DICOM viewer. ICH volumes were calculated by the reference standard semiautomatic segmentation in OsiriX software and compared with calculated arithmetic methods (ABC/2, ABC/2.4, ABC/3, and 2/3SC) volumes. Volumes were compared by difference plots for specific groups: randomization ICH (n=374), 3- to 7-day postsurgical ICH (n=206), antithrombotic-associated ICH (n=79), irregular-shape ICH (n=703) and irregular-density ICH (n=650). Density and shape were measured by the Barras ordinal shape and density groups (1-5). The ABC/2.4 method had the closest agreement to the semiautomatic segmentation volume in all groups, except for the 3- to 7-day postsurgical ICH group where the ABC/3 method was superior. Although the ABC/2 formula for calculating elliptical ICH is well validated, it must be used with caution in ICH scans where the elliptical shape of ICH is a false assumption. We validated the adjustment of the ABC/2.4 method in randomization, antithrombotic-associated, heterogeneous-density, and irregular-shape ICH. URL: http://www.isrctn.com/ISRCTN22153967. Unique identifier: ISRCTN22153967. © 2018 American Heart Association, Inc.

Audit of CT reporting standards in cases of intracerebral haemorrhage at a comprehensive stroke centre in Australia.

PubMed

Barras, Christen D; Asadi, Hamed; Phal, Pramit M; Tress, Brian M; Davis, Stephen M; Desmond, Patricia M

2016-12-01

Multiple CT-derived biomarkers that are predictive of intracerebral haemorrhage (ICH) growth and outcome have been described in the literature, but the extent to which these appear in imaging reports of ICH is unknown. The aim of this retrospective process audit was to determine which of the known predictors of ICH outcome was recorded in reports of the disease, with a view to providing reporting recommendations, as appropriate. We examined the initial CT report of patients diagnosed with ICH presenting to a metropolitan comprehensive stroke centre and meeting inclusion criteria during the audit period between 1 March 2013 and 28 February 2014. Each report was assessed for the inclusion of the following ICH characteristics: the number of measurement dimensions; volume; location; hydrocephalus; shape; density; 'CTA spot sign' (where CTA was performed). A total of 100 patients met audit inclusion criteria. At least one ICH dimension was recorded in 90% of reports; however, 39% did not include the measurements in three dimensions and volume was reported in just 6%. No ICH dimension was recorded in 10% of reports. With the exception of density and shape, reporting of other CT features exceeded 95%. Where CTA was performed (58%), 14 (24%) of 58 reported the 'CTA spot sign' status. In this audit, volume was the most under-reported of the established ICH characteristics predictive of ICH outcome. Readily calculated from multiplanar reformats using the ABC/2 technique, the routine reporting of ICH volume is recommended. More reporting attention to ICH density heterogeneity and shape irregularity is encouraged, given their emerging importance. Where acute CTA is performed, the presence of any dynamic haemorrhage (CTA spot sign) should be reported. © 2016 The Royal Australian and New Zealand College of Radiologists.

Rocket observations of electron-density irregularities in the equatorial ionosphere below 200 km

NASA Technical Reports Server (NTRS)

Klaus, D. E.; Smith, L. G.

1978-01-01

Nike Apache rockets carring instrumentation to measure electron density and its fine structure in the equatorial ionosphere were launched from Chilca, Peru in May and June 1975. The fine structure experiment and the data reduction system are described. Results obtained from this system are presented and compared with those obtained by VHF radar and from other rocket studies. A description of the equatorial ionosphere and its features is also presented.

Energetic efficiency, menstrual irregularity, and bone mineral density in elite professional female ballet dancers.

PubMed

Doyle-Lucas, Ashley F; Akers, Jeremy D; Davy, Brenda M

2010-01-01

Sports that emphasize low body weight for optimal performance, such as ballet, are associated with an increased prevalence of the female athlete triad (FT). Previous research in this area that involves dancers has been limited; the majority of studies have been performed on adolescents training in classical ballet, and not professional adult dancers. The purpose of this study is to compare the physical and behavioral characteristics of female elite ballet dancers to sedentary, recreationally active non-dancing controls, with regard to characteristics of the FT and energetic efficiency. Women aged 18 to 35 years were recruited as participants. The dancers (N = 15) and non-dancing controls (N = 15) were pair-matched via age (dancers: 24.3 ± 1.3 years; controls: 23.7 ± 0.9 years), body mass index (dancers: 18.9 ± 0.2; controls: 19.4 ± 0.2 kg/m 2 ), and fat-free mass (dancers: 44.3 ± 0.8; controls: 44.1 ± 0.9 kg). Assessments included habitual dietary intake using 4-day food records, self-reported physical activity, psychometric measures of eating behaviors, health and menstrual history, body composition and bone density (dual energy x-ray absorptiometry), and resting metabolic rate (RMR) assessed by indirect calorimetry. Characteristics of the FT, specifically menstrual irregularities (6 of 15 dancers reported irregular or no menses; 1 of 15 controls reported irregular menses) and low energy availability, were more prevalent in dancers than in pair-matched controls. Despite having a similar fat-free mass (FFM), dancers had a significantly lower absolute RMR (dancers: 1367 ± 27; controls: 1454 ± 34 kcal/d; p ≤ 0.05) and significantly lower RMR relative to FFM (dancers: 30.9 ± 0.6; controls: 33.1 ± 0.8 kcal/kg fat-free mass/d; p ≤ 0.05). Energy intake between dancers (1577 ± 89 kcal/d) and pair-matched controls (2075 ± 163 kcal/d) also differed significantly (p ≤ 0.01). Six of the 15 dancers met the criteria for the FT (including low bone mineral density, menstrual irregularities, and eating pathology accompanied by low energy availability) and, therefore, represent a population of individuals afflicted with this disorder. These findings provide insight as to the metabolic impact of chronic energy restriction, and suggest that alterations in RMR (i.e., energetic efficiency) may be an indicator of low energy availability. Future larger-scale studies are warranted to address this possibility. Interventions aimed at increasing energy availability in elite female ballet dancers may be needed to promote optimal health status.

Bottomside sinusoidal irregularities in the equatorial F region. II - Cross-correlation and spectral analysis

NASA Technical Reports Server (NTRS)

Cragin, B. L.; Hanson, W. B.; Mcclure, J. P.; Valladares, C. E.

1985-01-01

Equatorial bottomside sinusoidal (BSS) irregularities have been studied by applying techniques of cross-correlation and spectral analysis to the Atmosphere Explorer data set. The phase of the cross-correlations of the plasma number density is discussed and the two drift velocity components observed using the retarding potential analyzer and ion drift meter on the satellite are discussed. Morphology is addressed, presenting the geographical distributions of the occurrence of BSS events for the equinoxes and solstices. Physical processes including the ion Larmor flux, interhemispheric plasma flows, and variations in the lower F region Pedersen conductivity are invoked to explain the findings.

Bivariate spline solution of time dependent nonlinear PDE for a population density over irregular domains.

PubMed

Gutierrez, Juan B; Lai, Ming-Jun; Slavov, George

2015-12-01

We study a time dependent partial differential equation (PDE) which arises from classic models in ecology involving logistic growth with Allee effect by introducing a discrete weak solution. Existence, uniqueness and stability of the discrete weak solutions are discussed. We use bivariate splines to approximate the discrete weak solution of the nonlinear PDE. A computational algorithm is designed to solve this PDE. A convergence analysis of the algorithm is presented. We present some simulations of population development over some irregular domains. Finally, we discuss applications in epidemiology and other ecological problems. Copyright © 2015 Elsevier Inc. All rights reserved.

Ionospheric scintillation detection based on GPS observations, a case study over Iran

NASA Astrophysics Data System (ADS)

Sobhkhiz Miandehi, Sahar; Alizadeh Elizei, M. Mahdi; Schuh, Harald

2017-04-01

Global Positioning System (GPS) which is used extensively for various purposes such as navigation, surveying, remote sensing and telecommunication, is strongly affected by the earth's upper atmosphere, the ionosphere. Ionosphere is a highly variable region with complex physical characteristics in which the density of free electrons are large enough to have considerable effects on signals' propagation travelling through this dispersive medium. As GPS signals travel through the ionosphere, they may experience rapid amplitude fluctuations or unexpected phase changes. This is referred to as ionospheric scintillation. Ionospheric scintillation which is caused by small scale irregularities in the electron density, is one of the dominant propagation disturbances at radio frequency signals. These irregularities severely affect the accuracy and reliability of GPS measurements. Therefore it is necessary to investigate ionospheric scintillation and its effects on GPS observations. The focus of this paper is to detect ionospheric scintillations over Iran's region, during different periods of solar activity and to investigate these effects on GPS observations in more detail. Furthermore the effects of these irregularities on regional modeling of ionosphere over Iran is also investigated. The results show that effectiveness of this phenomenon depends on geographic location, local time and global geomagnetic storm index (kp index). The required data for this investigation are ground based measurements of permanent GPS stations over Iran, established by the National Cartographic Center of Iran (NCC).

Automatic estimation of dynamics of ionospheric disturbances with 1–15 minute lifetimes as derived from ISTP SB RAS fast chirp-ionosonde data

NASA Astrophysics Data System (ADS)

Berngardt, Oleg; Bubnova, Tatyana; Podlesnyi, Aleksey

2018-03-01

We propose and test a method of analyzing ionograms of vertical ionospheric sounding, which is based on detecting deviations of the shape of an ionogram from its regular (averaged) shape. We interpret these deviations in terms of reflection from the electron density irregularities at heights corresponding to the effective height. We examine the irregularities thus discovered within the framework of a model of a localized uniformly moving irregularity, and determine their characteristic parameters: effective heights and observed vertical velocities. We analyze selected experimental data for three seasons (spring, winter, autumn) obtained nearby Irkutsk with a fast chirp ionosonde of ISTP SB RAS in 2013-2015. The analysis of six days of observations conducted in these seasons has shown that in the observed vertical drift of the irregularities there are two characteristic distributions: wide velocity distribution with nearly 0 m/s mean and with the standard deviation of ∼250 m/s and narrow distribution with nearly -160 m/s mean. The analysis has demonstrated the effectiveness of the proposed algorithm for the automatic analysis of vertical sounding data with high repetition rate.

Effect of Particle Morphology on the Reactivity of Explosively Dispersed Titanium Particles

NASA Astrophysics Data System (ADS)

Frost, David; Cairns, Malcolm; Goroshin, Samuel; Zhang, Fan

2009-06-01

The effect of particle morphology on the reaction of titanium (Ti) particles explosively dispersed during the detonation of either cylindrical or spherical charges has been investigated experimentally. The explosive charges consisted of packed beds of Ti particles saturated with nitromethane. The reaction behavior of irregularly-shaped Ti particles in three size ranges is compared with tests with spherical Ti particles. The particle reaction is strongly dependent on particle morphology, e.g., 95 μm spherical Ti particles failed to ignite (in cylinders up to 49 mm in dia), whereas similarly sized irregular Ti particles readily ignited. For irregular particles, the uniformity of ignition on the particle cloud surface was almost independent of particle size, but depended on charge diameter. As the charge diameter was reduced, ignition in the conically expanding particle cloud occurred only at isolated spots or bands. For spherical charges, although large irregular Ti particles ignited promptly and uniformly throughout the particle cloud, the smallest particles dispersed nonuniformly and ignition occurred at isolated locations. In general, particle ignition is a competition between particle heating (which is influenced by particle morphology, size, number density and the local thermodynamic history) and expansion cooling of the products.

Synovial hemangioma in an adult horse.

PubMed

Holzhausen, Lars; Nowak, Michael; Junginger, Johannes; Puff, Christina

2012-03-01

A 15-year-old gelding presented with a progressive lameness of the left forelimb of 2.5 months duration. Clinically, a dilation of the deep flexor tendon sheath with a firm elastic consistency and a pronounced tenderness was noted. Ultrasonically, a marked swelling of the flexor tendon sheath with an irregular density of the mesotendineum was observed. The white, firm material forming a nodular distension of the flexor tendon sheath with a diameter of approximately 1 cm was excised and sent for histopathological examination. Biopsies of the deep flexor tendon and corresponding tendon sheath were sent for histopathological evaluation. Histologically, the mass consisted of clefts and numerous anastomosing vascular channels extending between the collagen fibers of the deep flexor tendon. These capillary-like spaces were lined by neoplastic cells that were flattened to polygonal and contained few erythrocytes. There was 0 to 1 mitotic figure per 10 high power fields (400×). Immunohistochemically, the neoplastic cells stained positive for vimentin and factor VIII-related antigen. Adjacent to the neoplastic endothelial cells located pericytes expressed α-smooth muscle actin antigen. Based on the histopathological and immunohistochemical features, synovial hemangioma was diagnosed. One year after surgery, the horse has shown no lameness.

3D tomography of midlatitude sporadic-E in Japan from GNSS-TEC data

NASA Astrophysics Data System (ADS)

Muafiry, Ihsan Naufal; Heki, Kosuke; Maeda, Jun

2018-03-01

We studied ionospheric irregularities caused by midlatitude sporadic-E ( Es) in Japan using ionospheric total electron content (TEC) data from a dense GNSS array, GEONET, with a 3D (three-dimensional) tomography technique. Es is a thin layer of unusually high ionization that appears at altitudes of 100 km. Here, we studied five cases of Es irregularities in 2010 and 2012, also reported in previous studies, over the Kanto and Kyushu Districts. We used slant TEC residuals as the input and estimated the number of electron density anomalies of more than 2000 small blocks with dimensions of 20-30 km covering a horizontal region of 300 × 500 km. We applied a continuity constraint to stabilize the solution and performed several different resolution tests with synthetic data to assess the accuracy of the results. The tomography results showed that positive electron density anomalies occurred at the E region height, and the morphology and dynamics were consistent with those reported by earlier studies.

Transport Properties of the Nuclear Pasta Phase with Quantum Molecular Dynamics

NASA Astrophysics Data System (ADS)

Nandi, Rana; Schramm, Stefan

2018-01-01

We study the transport properties of nuclear pasta for a wide range of density, temperature, and proton fractions, relevant for different astrophysical scenarios adopting a quantum molecular dynamics model. In particular, we estimate the values of shear viscosity as well as electrical and thermal conductivities by calculating the static structure factor S(q) using simulation data. In the density and temperature range where the pasta phase appears, the static structure factor shows irregular behavior. The presence of a slab phase greatly enhances the peak in S(q). However, the effect of irregularities in S(q) on the transport coefficients is not very dramatic. The values of all three transport coefficients are found to have the same orders of magnitude as found in theoretical calculations for the inner crust matter of neutron stars without the pasta phase; therefore, the values are in contrast to earlier speculations that a pasta layer might be highly resistive, both thermally and electrically.

Resonant frequencies of irregularly shaped microstrip antennas using method of moments

NASA Technical Reports Server (NTRS)

Deshpande, Manohar D.; Shively, David G.; Cockrell, C. R.

1993-01-01

This paper describes an application of the method of moments to determine resonant frequencies of irregularly shaped microstrip patches embedded in a grounded dielectric slab. For analysis, the microstrip patch is assumed to be excited by a linearly polarized plane wave that is normal to the patch. The surface-current density that is induced on the patch because of the incident field is expressed in terms of subdomain functions by dividing the patch into identical rectangular subdomains. The amplitudes of the subdomain functions, as a function of frequency, are determined using the electric-field integral equation (EFIE) approach in conjunction with the method of moments. The resonant frequencies of the patch are then obtained by selecting the frequency at which the amplitude of the surface-current density is real. The resonant frequencies of the equilateral triangular and other nonrectangular patches are computed using the present technique, and these frequencies are compared with measurements and other independent calculations.

Polycystic ovarian syndrome (PCOS), related symptoms/sequelae, and breast cancer risk in a population-based case-control study

PubMed Central

Kim, Jayeon; Mersereau, Jennifer E.; Khankari, Nikhil; Bradshaw, Patrick T.; McCullough, Lauren E.; Cleveland, Rebecca; Shantakumar, Sumitra; Teitelbuam, Susan L.; Neugut, Alfred I.; Senie, Ruby T.; Gammon, Marilie D.

2016-01-01

Purpose Despite the overlap between the clinical symptoms/sequelae of polycystic ovarian syndrome (PCOS) and many known reproductive risk factors for breast cancer, the relationship between PCOS and breast cancer remains unclear, possibly because of the complex heterogeneity and challenges in diagnosing PCOS over time. We hypothesized that PCOS, specific PCOS-related symptoms/sequelae, or clusters of PCOS-related symptoms/sequelae, may be differentially associated with pre- vs. postmenopausal breast cancer risk. Materials and Methods Cases were 1,508 women newly diagnosed with a first primary in situ or invasive breast, and the 1,556 population-based controls were frequency-matched by age. Results History of physician-diagnosed PCOS was reported by 2.2% (n=67), among whom oral contraceptive (OC) use, irregular menstruation, and infertility due to ovulatory dysfunction were common. Using unconditional logistic regression, adjusted odds ratios (95% confidence intervals) for PCOS were increased for premenopausal [2.74 (1.13, 6.63)], but not post-menopausal breast cancer [0.87 (0.44, 1.71)]. We used cluster analysis to investigate whether risk among all women varied by PCOS-related symptoms/sequelae, such as reproductive irregularities, OC use, and components of insulin resistance. In the cluster analysis, odds ratios were elevated among premenopausal women who had a history of OC use and no ovulatory dysfunction [1.39 (1.03, 1.88)], compared to those with fewer number of PCOS-related symptoms/sequelae. Conclusion PCOS, and associated PCOS-related symptoms/sequelae including OC use, may play a role in the development of premenopausal breast cancer. Our findings require confirmation in studies with a larger number of premenopausal women with systematically applied diagnostic criteria for PCOS. PMID:26797454

Polycystic ovarian syndrome (PCOS), related symptoms/sequelae, and breast cancer risk in a population-based case-control study.

PubMed

Kim, Jayeon; Mersereau, Jennifer E; Khankari, Nikhil; Bradshaw, Patrick T; McCullough, Lauren E; Cleveland, Rebecca; Shantakumar, Sumitra; Teitelbuam, Susan L; Neugut, Alfred I; Senie, Ruby T; Gammon, Marilie D

2016-03-01

Despite the overlap between the clinical symptoms/sequelae of polycystic ovarian syndrome (PCOS) and many known reproductive risk factors for breast cancer, the relationship between PCOS and breast cancer remains unclear, possibly because of the complex heterogeneity and challenges in diagnosing PCOS over time. We hypothesized that PCOS, specific PCOS-related symptoms/sequelae, or clusters of PCOS-related symptoms/sequelae may be differentially associated with pre- versus postmenopausal breast cancer risk. Cases were 1,508 women newly diagnosed with a first primary in situ or invasive breast, and the 1,556 population-based controls were frequency-matched by age. History of physician-diagnosed PCOS was reported by 2.2 % (n = 67), among whom oral contraceptive (OC) use, irregular menstruation, and infertility due to ovulatory dysfunction were common. Using unconditional logistic regression, adjusted odds ratios (95 % CI) for PCOS were increased for premenopausal [2.74 (1.13, 6.63)], but not postmenopausal breast cancer [0.87 (0.44, 1.71)]. We used cluster analysis to investigate whether risk among all women varied by PCOS-related symptoms/sequelae, such as reproductive irregularities, OC use, and components of insulin resistance. In the cluster analysis, odds ratios were elevated among premenopausal women who had a history of OC use and no ovulatory dysfunction [1.39 (1.03, 1.88)], compared to those with fewer number of PCOS-related symptoms/sequelae. PCOS and associated PCOS-related symptoms/sequelae including OC use may play a role in the development of premenopausal breast cancer. Our findings require confirmation in studies with a larger number of premenopausal women with systematically applied diagnostic criteria for PCOS.

Extended Schmidt law holds for faint dwarf irregular galaxies

NASA Astrophysics Data System (ADS)

Roychowdhury, Sambit; Chengalur, Jayaram N.; Shi, Yong

2017-12-01

Context. The extended Schmidt law (ESL) is a variant of the Schmidt which relates the surface densities of gas and star formation, with the surface density of stellar mass added as an extra parameter. Although ESL has been shown to be valid for a wide range of galaxy properties, its validity in low-metallicity galaxies has not been comprehensively tested. This is important because metallicity affects the crucial atomic-to-molecular transition step in the process of conversion of gas to stars. Aims: We empirically investigate for the first time whether low metallicity faint dwarf irregular galaxies (dIrrs) from the local universe follow the ESL. Here we consider the "global" law where surface densities are averaged over the galactic discs. dIrrs are unique not only because they are at the lowest end of mass and star formation scales for galaxies, but also because they are metal-poor compared to the general population of galaxies. Methods: Our sample is drawn from the Faint Irregular Galaxy GMRT Survey (FIGGS) which is the largest survey of atomic hydrogen in such galaxies. The gas surface densities are determined using their atomic hydrogen content. The star formation rates are calculated using GALEX far ultraviolet fluxes after correcting for dust extinction, whereas the stellar surface densities are calculated using Spitzer 3.6 μm fluxes. The surface densities are calculated over the stellar discs defined by the 3.6 μm images. Results: We find dIrrs indeed follow the ESL. The mean deviation of the FIGGS galaxies from the relation is 0.01 dex, with a scatter around the relation of less than half that seen in the original relation. In comparison, we also show that the FIGGS galaxies are much more deviant when compared to the "canonical" Kennicutt-Schmidt relation. Conclusions: Our results help strengthen the universality of the ESL, especially for galaxies with low metallicities. We suggest that models of star formation in which feedback from previous generations of stars set the pressure in the interstellar medium and affect ongoing star formation, are promising candidates for explaining the ESL. We also confirm that ESL is an independent relation and not a form of a relation between star formation efficiency and metallicity.

Synthesis of nanostructured/macroscopic low-density copper foams based on metal-coated polymer core–shell particles [Templated synthesis of nanowalled low-density copper foams

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kim, Sung Ho; Bazin, Nick; Shaw, Jessica I.

A robust, millimeter-sized low-density Cu foam with ~90% (v/v) porosity, ~30 nm thick walls, and ~1 μm diameter spherical pores is prepared by the slip-casting of metal-coated polymer core–shell particles followed by a thermal removal of the polymer. In this paper, we report our key findings that enable the development of the low-density Cu foams. First, we need to synthesize polystyrene (PS) particles coated with a very thin Cu layer (in the range of tens of nanometers). A simple reduction in the amount of Cu deposited onto the PS was not sufficient to form such a low-density Cu foams duemore » to issues related to foam collapse and densification upon the subsequent polymer removal step. Precise control over the morphology of the Cu coating on the particles is essential for the synthesis of a lower density of foams. Second, improving the dispersion of PS–Cu particles in a suspension used for the casting as well as careful optimization of a baking condition minimize the formation of irregular large voids, leading to Cu foams with a more uniform packing and a better connectivity of neighboring Cu hollow shells. Finally, we analyzed mechanical properties of the Cu foams with a depth-sensing indentation test. The uniform Cu foams show a significant improvement in mechanical properties (~1.5× modulus and ~3× hardness) compared to those of uncontrolled foam samples with a similar foam density but irregular large voids. As a result, higher surface areas and a good electric conductivity of the Cu foams present a great potential to future applications.« less

Synthesis of nanostructured/macroscopic low-density copper foams based on metal-coated polymer core–shell particles [Templated synthesis of nanowalled low-density copper foams

DOE PAGES

Kim, Sung Ho; Bazin, Nick; Shaw, Jessica I.; ...

2016-12-06

A robust, millimeter-sized low-density Cu foam with ~90% (v/v) porosity, ~30 nm thick walls, and ~1 μm diameter spherical pores is prepared by the slip-casting of metal-coated polymer core–shell particles followed by a thermal removal of the polymer. In this paper, we report our key findings that enable the development of the low-density Cu foams. First, we need to synthesize polystyrene (PS) particles coated with a very thin Cu layer (in the range of tens of nanometers). A simple reduction in the amount of Cu deposited onto the PS was not sufficient to form such a low-density Cu foams duemore » to issues related to foam collapse and densification upon the subsequent polymer removal step. Precise control over the morphology of the Cu coating on the particles is essential for the synthesis of a lower density of foams. Second, improving the dispersion of PS–Cu particles in a suspension used for the casting as well as careful optimization of a baking condition minimize the formation of irregular large voids, leading to Cu foams with a more uniform packing and a better connectivity of neighboring Cu hollow shells. Finally, we analyzed mechanical properties of the Cu foams with a depth-sensing indentation test. The uniform Cu foams show a significant improvement in mechanical properties (~1.5× modulus and ~3× hardness) compared to those of uncontrolled foam samples with a similar foam density but irregular large voids. As a result, higher surface areas and a good electric conductivity of the Cu foams present a great potential to future applications.« less

Can We Confidently Diagnose Pilomatricoma with Fine Needle Aspiration Cytology?

PubMed Central

WONG, Yin-Ping; MASIR, Noraidah; SHARIFAH, Noor Akmal

2015-01-01

Pilomatricomas can be confidently diagnosed cytologically due to their characteristic cytomorphological features. However, these lesions are rarely encountered by cytopathologists and thus pose a diagnostic dilemma to even experienced individuals, especially when the lesions are focally sampled. We describe two cases of histologically confirmed pilomatricoma. The first case is of a 13-year-old boy with posterior cervical ‘lymphadenopathy’, and the second one is of a 12-year-old girl with a lower cheek swelling. Both aspirates comprised predominantly atypical basal-like cells, with prominent nucleoli. ‘Ghost cells’ were readily identified by cell block in case two, but cell block in case one yielded no diagnostic material. In case two, pilomatricoma was accurately diagnosed pre-operatively. A cytological suspicion of a neoplastic process was raised in case one. Despite being diagnostically challenging, pilomatricoma can be diagnosed with careful observation of two unique cytological features of the lesions: (1) pathognomonic ‘ghost cells’ and (2) irregular, saw-toothed, loosely cohesive basaloid cells, with prominent nucleoli. The role of thorough sampling of the lesion, with multiple passes of various sites, cannot be overemphasized. PMID:25892955

Geoboard and Balance Activities for the Gifted Child.

ERIC Educational Resources Information Center

Bondy, Kay W.

1979-01-01

The author describes mathematics activities for gifted children which make use of the geoboard and balance. The problem, solutions, and theoretical backing are provided for determining areas of squares, areas of irregular shapes, the weight of popped and unpopped popcorn, kernels, and liquid mass and density. (SBH)

Technical Note: Stored grain volume measurement using a low density point cloud

USDA-ARS?s Scientific Manuscript database

The mass of stored grain is often determined from volume measurements by crop insurers, government auditors, and stored grain managers conducting inventories. Recent increases in bin size have accentuated the difficulty of accounting for irregularities and variations in surface conditions in calcula...

Use of dry-milling derived thin stillage for producing eicosapentaenoic acid (EPA) by the fungus Pythium irregulare.

PubMed

Liang, Yi; Zhao, Xuefei; Strait, Megan; Wen, Zhiyou

2012-05-01

This study was to explore the use of thin stillage, a major byproduct in dry milling corn-ethanol plants, for production of eicosapentaenoic acid (EPA) by the fungus Pythium irregulare. Thin stillage contains various compounds that were ideal for fungal growth. Thin stillage concentration and temperature played important roles in fungal growth and EPA production. When 50% thin stillage was used in a stepwise temperature shift culture process, the cell density reached 23 g/L at day 9 with EPA yield and productivity of 243 and 27 mg/L day, respectively. The fungal biomass contained 39% lipid, 28% protein, 30% carbohydrate, and 3% ash. The fungal culture also generated a nutrient-depleted liquid by removing organic compounds in the raw thin stillage. The results collectively showed a new use of thin stillage by feeding to the fungus P. irregulare for producing omega-3 fatty acids. Copyright © 2012 Elsevier Ltd. All rights reserved.

Particle morphology influence on mechanical and biocompatibility properties of injection molded Ti alloy powder.

PubMed

Gülsoy, H Özkan; Gülsoy, Nagihan; Calışıcı, Rahmi

2014-01-01

Titanium and Titanium alloys exhibits properties that are excellent for various bio-applications. Metal injection molding is a processing route that offers reduction in costs, with the added advantage of near net-shape components. Different physical properties of Titanium alloy powders, shaped and processed via injection molding can achieve high complexity of part geometry with mechanical and bioactivity properties, similar or superior to wrought material. This study describes that the effect of particle morphology on the microstructural, mechanical and biocompatibility properties of injection molded Ti-6Al-4V (Ti64) alloy powder for biomaterials applications. Ti64 powders irregular and spherical in shape were injection molded with wax based binder. Binder debinding was performed in solvent and thermal method. After debinding the samples were sintered under high vacuum. Metallographic studies were determined to densification and the corresponding microstructural changes. Sintered samples were immersed in a simulated body fluid (SBF) with elemental concentrations that were comparable to those of human blood plasma for a total period of 15 days. Both materials were implanted in fibroblast culture for biocompatibility evaluations were carried out. The results show that spherical and irregular powder could be sintered to a maximum theoretical density. Maximum tensile strength was obtained for spherical shape powder sintered. The tensile strength of the irregular shape powder sintered at the same temperature was lower due to higher porosity. Finally, mechanical tests show that the irregular shape powder has lower mechanical properties than spherical shape powder. The sintered irregular Ti64 powder exhibited better biocompatibility than sintered spherical Ti64 powder. Results of study showed that sintered spherical and irregular Ti64 powders exhibited high mechanical properties and good biocompatibility properties.

Detection of the Equatorial Ionospheric Irregularities Using the POD GPS Measurements

NASA Astrophysics Data System (ADS)

Zakharenkova, I.; Astafyeva, E.; Cherniak, I.

2015-12-01

By making use of GPS measurements from Precise Orbit Determination (POD) GPS antenna onboard Low Earth Orbit (LEO) satellites we present results of the equatorial irregularities/plasma bubbles detection. For a given research we use data from a multi-satellite constellation consisting of the three Swarm satellites and the TerraSAR-X satellite. The major advantage of such LEO constellation is rather similar orbit altitude of ~500 km. The GPS-based indices, characterizing the occurrence and the strength of the ionospheric irregularities, were derived from the LEO GPS observations of a zenith-looking onboard GPS antenna. To study GPS fluctuation activity at the topside equatorial ionosphere we used TEC-based indices ROT (rate of TEC change) and ROTI (rate of TEC Index), proposed by Pi et al. (1997). We demonstrate a successful implementation of this technique for several case studies of the equatorial plasma bubbles occurrence in the post-midnight and morning LT hours during the year 2014. The ionospheric irregularities detected with GPS technique in Swarm/TerrasSAR-X data are consistent with the in situ plasma density variations registered by the three Swarm satellites (PLP measurements), as well as by three DMSP satellites at ~840 km orbital height, which indicate a large altitudinal extent of the observed phenomenon. Also we analyzed the global/seasonal distribution of the ionospheric irregularities at the topside equatorial region caused the phase fluctuations in GPS measurements onboard LEO satellite. We demonstrate that ROT/ROTI technique can be applied to LEO GPS data for geomagnetically quiet and disturbed conditions, as well as detection of the storm-induced equatorial irregularities in the morning local time.

Method for hot pressing irregularly shaped refractory articles

DOEpatents

Steinkamp, William E.; Ballard, Ambrose H.

1982-01-01

The present invention is directed to a method for hot pressing irregularly haped refractory articles with these articles of varying thickness being provided with high uniform density and dimensional accuracy. Two partially pressed compacts of the refractory material are placed in a die cavity between displaceable die punches having compact-contacting surfaces of the desired article configuration. A floating, rotatable block is disposed between the compacts. The displacement of the die punches towards one another causes the block to rotate about an axis normal to the direction of movement of the die punches to uniformly distribute the pressure loading upon the compacts for maintaining substantially equal volume displacement of the powder material during the hot pressing operation.

The Irregular Moons of Saturn

NASA Astrophysics Data System (ADS)

Denk, Tilmann; Mottola, Stefano; Tosi, Federico; Bottke, William; Hamilton, Douglas P.

2017-10-01

The 38 irregular moons of Saturn, all but Phoebe discovered between 2000 and 2007, outnumber the planet's classical satellites. Observations from the ground and from near-Earth space have revealed orbits, sizes, and colors and have hinted at the existence of dynamical families, indicative of collisional evolution and common progenitors. More recently, remote observations of many irregular satellites with the Cassini spacecraft produced lightcurves that helped determine rotational periods, coarse shape models, potential hemispheric color heterogeneities, and other basic properties.From Cassini, a total of 25 Saturnian irregulars have been observed with the ISS camera. Their rotational periods range from 5.45 h to 76.13 h. The absence of fast rotators is evident. Among main-belt asteroids of the same size range (~4 to ~45 km), one third of the objects have faster rotations, indicating that many irregulars should be low-density objects.While the origin of the irregulars is still debated, capture of comets via three-body interactions during giant planets encounters does the best job thus far at reproducing the observed prograde/retrograde orbits. Data from the ground, near-Earth spacecraft, and Cassini as well as modeling results suggest the population visible today has experienced substantial collisional evolution. It may be that only Phoebe has survived relatively intact. The small particle debris drifts toward Saturn by P-R drag, with most of it swept up by Titan. Only remnants of this process are visible today.Our current knowledge on the Saturnian irregulars will be summarized in a chapter [1] in the book "Enceladus and the Icy Moons of Saturn" [2]. The talk will give an overview on the chapter's content, which covers the following topics: Orbital "architecture" (a,e,i), sizes and colors, Cassini observations and results, Phoebe, origin, an outlook.[1] Denk, T., Mottola, S., Tosi, F., Bottke, W.F., Hamilton, D.P. (2018): The Irregular Satellites of Saturn. In: Enceladus and the Icy Moons of Saturn (Schenk, P. et al., eds.), Space Science Series, The University of Arizona Press. In press.[2] See http://www.uapress.arizona.edu/Books/bid2726.htm

Mid-latitude Plasma Irregularities During Sub-Auroral Polarization Streams

NASA Astrophysics Data System (ADS)

Smith, N.; Loper, R. D.

2017-12-01

Geomagnetic storming impacts the ionosphere in different ways at different latitudes. In the mid latitudes, Sub-Auroral Polarization Streams (SAPS) may trigger a redistribution of plasma leading to the creation of ionospheric troughs, storm enhanced density plumes, and acceleration of sub-auroral ion drifts. Solar cycle data, real time space weather satellite data, and radar data will be analyzed to study mid-latitude plasma densities and characterize the plasma anomalies SAPS create in order to increase short-term mid-latitude space weather forecasting.

Ichnology of an upper carboniferous fluvio-estuarine paleovalley: The tonganoxie sandstone, buildex quarry, eastern Kansas, USA

USGS Publications Warehouse

Buatois, L.A.; Mangano, M.G.; Maples, C.G.; Lanier, Wendy E.

1998-01-01

Tidal rhythmites of the Tonganoxie Sandstone Member (Stranger Formation, Douglas Group) at Buildex Quarry, eastern Kansas, contain a relatively diverse ichnofauna. The assemblage includes arthropod locomotion (Dendroidichnites irregulare, Diplichnites gouldi type A and B, Diplopodichnus biformis, Kouphichnium isp., Mirandaichnium famatinense, and Stiaria intermedia), resting (Tonganoxichnus buildexensis) and feeding traces (Stiallia pilosa, Tonganoxichnus ottawensis); grazing traces (Gordia indianaensis, Helminthoidichnites tenuis, Helminthopsis hieroglyphica); feeding structures (Circulichnis montanus, Treptichnus bifurcus, Treptichnus pollardi, irregular networks), fish traces (Undichna britannica, Undichna simplicitas), tetrapod trackways, and root traces. The taxonomy of some of these ichnotaxa is briefly reviewed and emended diagnoses for Gordia indianaensis and Helminthoidichnites tenuis are proposed. Additionally, the combined name Dendroidichnites irregulare is proposed for nested chevron trackways. Traces previously regarded as produced by isopods are reinterpreted as myriapod trackways (D. gouldi type B). Trackways formerly interpreted as limulid crawling and swimming traces are assigned herein to Kouphichnium isp and Dendroidichnites irregulare, respectively. Taphonomic analysis suggests that most grazing and feeding traces were formed before the arthropod trackways and resting traces. Grazing/feeding traces were formed in a soft, probably submerged substrate. Conversely, the majority of trackways and resting traces probably were produced subaerially in a firmer, dewatered and desiccated sediment. The Buildex Quarry ichnofauna records the activity of a terrestrial and freshwater biota. The presence of this assemblage in tidal rhythmites is consistent with deposition on tidal flats in the most proximal zone of the inner estuary, between the maximum landward limit of tidal currents and the salinity limit further towards the sea.

The climatology of low latitude ionospheric currents derived from CHAMP observations

NASA Astrophysics Data System (ADS)

Stolle, Claudia; Alken, Patrik

2010-05-01

The multi-year data base of magnetic field and ionospheric measurements from the CHAMP satellite contain enormous potential to investigate the behaviour and the origin of currents in the E and F region ionosphere. Special advantage is drawn from the satellite's near polar orbit and the full data coverage over all longitudes and local times. This paper will present findings about two prominent features of the low latitude ionosphere: equatorial plasma irregularities and the equatorial electrojet (EEJ). Equatorial plasma irregularities (commonly known as "bubbles") severely disturb the post sunset F region ionosphere and cause the strongest radio wave scintillations globally during solar maximum years. Using CHAMP vector magnetic field data, it was possible for the first time to show on a long term basis that equatorial plasma irregularities have signatures in all components of the magnetic field. The first ever global climatology of the occurrence rate of these magnetic signatures has been compiled. Such a data base of disturbed orbits is especially useful for core and crustal magnetic field modellers. The magnetic field observations of CHAMP, Ørsted, and SAC-C were employed to develop a climatological model of the EEJ. Measurements of the EEJ and empirical values from electron density and thermospheric density and winds have in addition enabled the development of a climatological model of the equatorial electric field. These results provide excellent opportunity to investigate the seasonal/longitudinal characteristics of the EEJ and the influence of atmospheric waves on E region dynamics.

VLF Transmitter Signal Power Loss to Quasi-Electrostatic Whistler Mode Waves in Regions Containing Plasma Density Irregularities

NASA Astrophysics Data System (ADS)

Bell, T. F.; Foust, F.; Inan, U. S.; Lehtinen, N. G.

2010-12-01

The energetic particles comprising the Earth’s radiation belts are an important component of Space Weather. The commonly accepted model of the quasi-steady radiation belts developed by Abel and Thorne [1998] proposes that VLF signals from powerful ground based transmitters determine the lifetimes of energetic radiation belt electrons (100 keV-1.5 MeV) on L shells in the range 1.3-2.8. The primary mechanism of interaction is pitch angle scattering during gyro-resonance. Recent observations [Starks et al., 2008] from multiple spacecraft suggest that the actual night time intensity of VLF transmitter signals in the radiation belts is approximately 20 dB below the level assumed in the Abel and Thorne model and approximately 10 dB below model values during the day. In this work we discuss one mechanism which might be responsible for a large portion of this intensity discrepancy. The mechanism is linear mode coupling between electromagnetic whistler mode waves and quasi-electrostatic whistler mode waves. As VLF electromagnetic whistler mode waves propagate through regions containing small scale (2-100 m) magnetic-field-aligned plasma density irregularities, they excite quasi-electrostatic whistler mode waves, and this excitation represents a power loss for the input waves. We construct plausible models of the irregularities in order to use numerical simulations to determine the characteristics of the mode coupling mechanism and the conditions under which the input VLF waves can lose significant power to the excited quasi-electrostatic whistler mode waves.

Thoracoscopic Surgery in a Patient with Multiple Esophageal Carcinomas after Surgery for Esophageal Achalasia.

PubMed

Yamasaki, Yuki; Tsukada, Tomoya; Aoki, Tatsuya; Haba, Yusuke; Hirano, Katsuhisa; Watanabe, Toshifumi; Kaji, Masahide; Shimizu, Koichi

2017-01-01

We present a case in which we used a thoracoscopic approach for resection of multiple esophageal carcinomas diagnosed 33 years after surgery for esophageal achalasia. A 68-year-old Japanese man had been diagnosed with esophageal achalasia and underwent surgical treatment 33 years earlier. He was examined at our hospital for annual routine checkup in which upper gastrointestinal endoscopy showed a "0-IIb+IIa" lesion in the middle esophagus. Iodine staining revealed multiple irregularly shaped iodine-unstained areas, the diagnosis of which was esophageal carcinoma. Thoracoscopic subtotal esophagectomy was performed. Esophageal carcinoma may occur many years after surgery for esophageal achalasia, even if the passage symptoms have improved. So, long-term periodic follow-up is necessary for detection of carcinoma at an earlier stage.

Thoracoscopic Surgery in a Patient with Multiple Esophageal Carcinomas after Surgery for Esophageal Achalasia

PubMed Central

Tsukada, Tomoya; Aoki, Tatsuya; Haba, Yusuke; Hirano, Katsuhisa; Watanabe, Toshifumi; Kaji, Masahide; Shimizu, Koichi

2017-01-01

We present a case in which we used a thoracoscopic approach for resection of multiple esophageal carcinomas diagnosed 33 years after surgery for esophageal achalasia. A 68-year-old Japanese man had been diagnosed with esophageal achalasia and underwent surgical treatment 33 years earlier. He was examined at our hospital for annual routine checkup in which upper gastrointestinal endoscopy showed a “0-IIb+IIa” lesion in the middle esophagus. Iodine staining revealed multiple irregularly shaped iodine-unstained areas, the diagnosis of which was esophageal carcinoma. Thoracoscopic subtotal esophagectomy was performed. Esophageal carcinoma may occur many years after surgery for esophageal achalasia, even if the passage symptoms have improved. So, long-term periodic follow-up is necessary for detection of carcinoma at an earlier stage. PMID:28951795

Analytical study of nighttime scintillations using GPS at low latitude station Bhopal

DOE Office of Scientific and Technical Information (OSTI.GOV)

Maski, Kalpana, E-mail: k-maski@rediffmail.com; Vijay, S. K.

2015-07-31

Sporadically structured ionosphere (i.e. in-homogeneities in refractive index) can cause fluctuations (due to refraction effects) on the radio signal that is passing through it. These fluctuations are called ionospheric scintillations. Low latitude region is suitable for studying these scintillations. The influence of the ionosphere on the propagation of the radio wave becomes very marked with reference to communication or navigational radio system at very low frequency (VLF) to a high frequency (HF), which operate over the distances of 1000 km or more. Radio wave communication at different frequencies depends on structure of the ionosphere. With the advent of the artificialmore » satellites, they are used as a prime mode of radio wave communication. Some natural perturbation termed as irregularities, are present in the form of electron density of the ionosphere that cause disruption in the radio and satellite communications. Therefore the study of the ionospheric irregularities is of practical importance, if one wishes to understand the upper atmosphere completely. In order to make these communications uninterrupted the knowledge of irregularities, which are present in the ionosphere are very important. These irregularities can be located and estimated with the help of Ionospheric TEC and Scintillation. Scintillation is generally confined to nighttime hours, particularly around equatorial and low latitudes.« less

Excitation thresholds of field-aligned irregularities and associated ionospheric hysteresis at very high latitudes observed using SPEAR-induced HF radar backscatter

NASA Astrophysics Data System (ADS)

Wright, D. M.; Dhillon, R. S.; Yeoman, T. K.; Robinson, T. R.; Thomas, E. C.; Baddeley, L. J.; Imber, S.

2009-07-01

On 10 October 2006 the SPEAR high power radar facility was operated in a power-stepping mode where both CUTLASS radars were detecting backscatter from the SPEAR-induced field-aligned irregularities (FAIs). The effective radiated power of SPEAR was varied from 1-10 MW. The aim of the experiment was to investigate the power thresholds for excitation (Pt) and collapse (Pc) of artificially-induced FAIs in the ionosphere over Svalbard. It was demonstrated that FAI could be excited by a SPEAR ERP of only 1 MW, representing only 1/30th of SPEAR's total capability, and that once created the irregularities could be maintained for even lower powers. The experiment also demonstrated that the very high latitude ionosphere exhibits hysteresis, where the down-going part of the power cycle provided a higher density of irregularities than for the equivalent part of the up-going cycle. Although this second result is similar to that observed previously by CUTLASS in conjunction with the Tromsø heater, the same is not true for the equivalent incoherent scatter measurements. The EISCAT Svalbard Radar (ESR) failed to detect any hysteresis in the plasma parameters over Svalbard in stark contract with the measurements made using the Tromsø UHF.

What do the cosmological supernova data really tell us?

NASA Astrophysics Data System (ADS)

Semiz, İbrahim; Kazım Çamlıbel, A.

2015-12-01

We try to reconstruct the scale factor a(t) of the universe from the SNe Ia data, i.e. the luminosity distance dL(z), using only the cosmological principle and the assumption that gravitation is governed by a metric theory. In our hence model-independent, or cosmographic study, we fit functions to dL(z) rather than a(t), since dL(z) is what is measured. We find that the acceleration history of the universe cannot be reliably determined in this approach due to the irregularity and parametrization-dependence of the results. However, adding the GRB data to the dataset cures most of the irregularities, at the cost of compromising the model-independent nature of the study slightly. Then we can determine the redshift of transition to cosmic acceleration as zt ~ 0.50 ± 0.09 for a flat universe (larger for positive spatial curvature).If Einstein gravity (GR) is assumed, we find a redshift at which the density of the universe predicted from the dL(z) data is independent of curvature. We use this point to derive an upper limit on matter density, hence a lower limit on the density of dark energy. While these limits do not improve the generally accepted ones, they are derived only using the dL(z) data.

Initial Results of DC Electric Fields, Associated Plasma Drifts, Magnetic Fields, and Plasma Waves Observed on the C/NOFS Satellite

NASA Technical Reports Server (NTRS)

Pfaff, R.; Freudenreich, H.; Bromund, K.; Klenzing, J.; Rowland, D.; Maynard, N.

2010-01-01

Initial results are presented from the Vector Electric Field Investigation (VEFI) on the Air Force Communication/Navigation Outage Forecasting System (C/NOFS) satellite, a mission designed to understand, model, and forecast the presence of equatorial ionospheric irregularities. The VEFI instrument includes a vector DC electric field detector, a fixed-bias Langmuir probe operating in the ion saturation regime, a flux gate magnetometer, an optical lightning detector, and associated electronics including a burst memory. Compared to data obtained during more active solar conditions, the ambient DC electric fields and their associated E x B drifts are variable and somewhat weak, typically < 1 mV/m. Although average drift directions show similarities to those previously reported, eastward/outward during day and westward/downward at night, this pattern varies significantly with longitude and is not always present. Daytime vertical drifts near the magnetic equator are largest after sunrise, with smaller average velocities after noon. Little or no pre-reversal enhancement in the vertical drift near sunset is observed, attributable to the solar minimum conditions creating a much reduced neutral dynamo at the satellite altitude. The nighttime ionosphere is characterized by larger amplitude, structured electric fields, even where the plasma density appears nearly quiescent. Data from successive orbits reveal that the vertical drifts and plasma density are both clearly organized with longitude. The spread-F density depletions and corresponding electric fields that have been detected thus far have displayed a preponderance to appear between midnight and dawn. Associated with the narrow plasma depletions that are detected are broad spectra of electric field and plasma density irregularities for which a full vector set of measurements is available for detailed study. Finally, the data set includes a wide range of ELF/VLF/HF oscillations corresponding to a variety of plasma waves, in particular banded ELF hiss, whistlers, and lower hybrid wave turbulence triggered by lightning-induced sferics. The VEFI data represents a new set of measurements that are germane to numerous fundamental aspects of the electrodynamics and irregularities inherent to the Earth's low latitude ionosphere.

Ionospheric Storm Effects and Equatorial Plasma Irregularities During the 17-18 March 2015 Event

NASA Technical Reports Server (NTRS)

Zhou, Yun-Liang; Luhr, Hermann; Xiong, Chao; Pfaff, Robert F.

2016-01-01

The intense magnetic storm on 17-18 March 2015 caused large disturbances of the ionosphere. Based on the plasma density (Ni) observations performed by the Swarm fleet of satellites, the Gravity Recovery and Climate Experiment mission, and the Communications/Navigation Outage Forecasting System satellite, we characterize the storm-related perturbations at low latitudes. All these satellites sampled the ionosphere in morning and evening time sectors where large modifications occurred. Modifications of plasma density are closely related to changes of the solar wind merging electric field (E (sub m)). We consider two mechanisms, prompt penetration electric field (PPEF) and disturbance dynamo electric field (DDEF), as the main cause for the Ni redistribution, but effects of meridional wind are also taken into account. At the start of the storm main phase, the PPEF is enhancing plasma density on the dayside and reducing it on the nightside. Later, DDEF takes over and causes the opposite reaction. Unexpectedly, there appears during the recovery phase a strong density enhancement in the morning/pre-noon sector and a severe Ni reduction in the afternoon/evening sector, and we suggest a combined effect of vertical plasma drift, and meridional wind is responsible for these ionospheric storm effects. Different from earlier studies about this storm, we also investigate the influence of storm dynamics on the initiation of equatorial plasma irregularities (EPIs). Shortly after the start of the storm main phase, EPIs appear in the post-sunset sector. As a response to a short-lived decline of E (sub m), EPI activity appears in the early morning sector. Following the second start of the main phase, EPIs are generated for a few hours in the late evening sector. However, for the rest of the storm main phase, no more EPIs are initiated for more than 12 hours. Only after the onset of recovery phase does EPI activity start again in the post-midnight sector, lasting more than 7 hours.This comprehensive view of ionospheric storm effects and plasma irregularities adds to our understanding of conditions that lead to ionospheric instabilities.

Investigating the Role of Gravity Wave on Equatorial Ionospheric Irregularities using SABER and C/NOFS Satellites Observations

NASA Astrophysics Data System (ADS)

Nigussie, M.; Damtie, B.; Moldwin, M.; Yizengaw, E.; Tesema, F.; Tebabal, A.

2017-12-01

Theoretical simulations have shown that gravity wave (GW) seeded perturbations amplified by Rayleigh-Taylor Instability (RTI) results in ESF (equatorial spread F); however, there have been limited observational studies using simultaneous observations of GW and ionospheric parameters. In this paper, for the fist time, simultaneous atmospheric temperature perturbation profiles that are due to GWs obtained from Sounding of the Atmosphere using Broadband Emission Radiometry (SABER) on-board the TIMED satellite and equatorial in -situ ion density and vertical plasma drift velocity observations with and without ESF activity obtained from C/NOFS satellites are used to investigate the effect of GW on the generation of ESF. The horizontal and vertical wavelengths of ionospheric oscillations and GWs respectively have been estimated applying wavelet transforms. Cross wavelet analysis has also been applied between two closely observed profiles of temperature perturbations to estimate the horizontal wavelength of the GWs. Moreover, vertically propagating GWs that dissipate energy at the upper atmosphere have been investigated using spectral analysis compared with theoretical results. The analysis show that when the ion density shows strong post sunset irregularity between 20 and 24 LT, vertically upward drift velocities increase between 17 and 19 LT, but it becomes vertically downward when the ion density shows smooth variation. The horizontal wavelengths estimated from C/NOFS and SABER observations show excellent agreement when ion density observations show strong fluctuations; otherwise, they have poor agreement. It is also found that altitude profiles of potential energy of GW increases up to 90 km and then decreases significantly. It is found that the vertical wavelength of GW, corresponding to the dominant spectral power, ranges from about 7 km to 20 km regardless of the situation of the ionosphere; however, GWs with vertical wavelengths between 100 m to 1 km are found to be saturated between 90 and 110 km whether the ionosphere exhibits irregularity or not. The above results imply that ESF is due to the amplification of perturbations as a result of energy dissipation from GW with vertical wavelength 100 m to 1 km by the RTI that is mainly controlled by Pre-Reversal Enhancement of the zonal electric field.

Ionospheric storm effects and equatorial plasma irregularities during the 17-18 March 2015 event

NASA Astrophysics Data System (ADS)

Zhou, Yun-Liang; Lühr, Hermann; Xiong, Chao; Pfaff, Robert F.

2016-09-01

The intense magnetic storm on 17-18 March 2015 caused large disturbances of the ionosphere. Based on the plasma density (Ni) observations performed by the Swarm fleet of satellites, the Gravity Recovery and Climate Experiment mission, and the Communications/Navigation Outage Forecasting System satellite, we characterize the storm-related perturbations at low latitudes. All these satellites sampled the ionosphere in morning and evening time sectors where large modifications occurred. Modifications of plasma density are closely related to changes of the solar wind merging electric field (Em). We consider two mechanisms, prompt penetration electric field (PPEF) and disturbance dynamo electric field (DDEF), as the main cause for the Ni redistribution, but effects of meridional wind are also taken into account. At the start of the storm main phase, the PPEF is enhancing plasma density on the dayside and reducing it on the nightside. Later, DDEF takes over and causes the opposite reaction. Unexpectedly, there appears during the recovery phase a strong density enhancement in the morning/prenoon sector and a severe Ni reduction in the afternoon/evening sector, and we suggest a combined effect of vertical plasma drift, and meridional wind is responsible for these ionospheric storm effects. Different from earlier studies about this storm, we also investigate the influence of storm dynamics on the initiation of equatorial plasma irregularities (EPIs). Shortly after the start of the storm main phase, EPIs appear in the postsunset sector. As a response to a short-lived decline of Em, EPI activity appears in the early morning sector. Following the second start of the main phase, EPIs are generated for a few hours in the late evening sector. However, for the rest of the storm main phase, no more EPIs are initiated for more than 12 h. Only after the onset of recovery phase does EPI activity start again in the postmidnight sector, lasting more than 7 h. This comprehensive view of ionospheric storm effects and plasma irregularities adds to our understanding of conditions that lead to ionospheric instabilities.

C/NOFS Satellite Electric Field and Plasma Density Observations of Plasma Instabilities Below the Equatorial F-Peak -- Evidence for Approximately 500 km-Scale Spread-F "Precursor" Waves Driven by Zonal Shear Flow and km-Scale, Narrow-Banded Irregularities

NASA Technical Reports Server (NTRS)

Pfaff, R.; Freudenreich, H.; Klenzing, J.; Liebrecht, C.; Valladares, C.

2011-01-01

As solar activity has increased, the ionosphere F-peak has been elevated on numerous occasions above the C/NOFS satellite perigee of 400km. In particular, during the month of April, 2011, the satellite consistently journeyed below the F-peak whenever the orbit was in the region of the South Atlantic anomaly after sunset. During these passes, data from the electric field and plasma density probes on the satellite have revealed two types of instabilities which had not previously been observed in the C/NOFS data set (to our knowledge): The first is evidence for 400-500km-scale bottomside "undulations" that appear in the density and electric field data. In one case, these large scale waves are associated with a strong shear in the zonal E x B flow, as evidenced by variations in the meridional (outward) electric fields observed above and below the F-peak. These undulations are devoid of smaller scale structures in the early evening, yet appear at later local times along the same orbit associated with fully-developed spread-F with smaller scale structures. This suggests that they may be precursor waves for spread-F, driven by a collisional shear instability, following ideas advanced previously by researchers using data from the Jicamarca radar. A second new result (for C/NOFS) is the appearance of km-scale irregularities that are a common feature in the electric field and plasma density data that also appear when the satellite is below the F -peak at night. The vector electric field instrument on C/NOFS clearly shows that the electric field component of these waves is strongest in the zonal direction. These waves are strongly correlated with simultaneous observations of plasma density oscillations and appear both with, and without, evidence of larger-scale spread-F depletions. These km-scale, quasi-coherent waves strongly resemble the bottomside, sinusoidal irregularities reported in the Atmosphere Explorer satellite data set by Valladares et al. [JGR, 88, 8025, 1983]. We interpret these new observations in terms of fundamental plasma instabilities associated with the unstable, nighttime equatorial ionosphere.

Space Shuttle Exhaust Modifications of the Mid-Latitude Ionospheric Plasma As Diagnosed By Ground Based Radar

NASA Astrophysics Data System (ADS)

Lind, F. D.; Erickson, P. J.; Bhatt, A.; Bernhardt, P. A.

2009-12-01

The Space Shuttle's Orbital Maneuvering System (OMS) engines have been used since the early days of the STS program for active ionospheric modification experiments designed to be viewed by ground based ionospheric radar systems. In 1995, the Naval Research Laboratory initiated the Shuttle Ionospheric Modification with Pulsed Localized Exhaust (SIMPLEX) Program using dedicated Space Shuttle OMS burns scheduled through the US Department of Defense's Space Test Program. SIMPLEX objectives include generation of localized ion-acoustic turbulence and the formation of ionospheric density irregularities for injections perpendicular to the local magnetic field, creating structures which can scatter incident UHF radar signals. We discuss radar observations made during several recent SIMPLEX mid-latitude experiments conducted over the Millstone Hill incoherent scatter radar system in Westford, Massachusetts. OMS engine firings release 10 kg/s of CO2, H2, H2O, and N2 molecules which charge exchange with ambient O+ ions in the F region, producing molecular ions and long lived electron density depletions as recombination occurs with ambient electrons. Depending on the magnetic field angle, the high velocity of the injected reactive exhaust molecules relative to the background ionosphere can create longitudinal propagating ion acoustic waves with amplitudes well above normal thermal levels and stimulate a wide variety of plasma instability processes. These effects produce high radar cross section targets readily visible to the Millstone Hill system, a high power large aperture radar designed to measure very weak scatter from the quiescent background ionosphere. We will survey the plasma instability parameter space explored to date and discuss plans for future SIMPLEX observations.

Investigation on etiology of hepatic venous obstruction Budd-Chiari syndrome.

PubMed

Tian, Zhi-Long; Jia, Gao-Lei; Xi, Hai-Lin; Feng, Su; Wang, Xiao-Kai; Li, Rui

2014-12-01

Budd-Chiari syndrome (BCS) is an uncommon clinical condition with a complex etiology. Pathogenesis of BCS is still poorly understood. We included hepatic veno-occlusive lesion tissues of 20 patients (patients group) with hepatic venous obstruction BCS and compared with 20 similar tissues with other etiologies (control group). Morphological changes in hepatic veno-occlusive lesion tissues and the positive expression of proliferating cell nuclear antigen (PCNA), C-myc, and P-53 were observed by the pathological examination (H&E staining) and immunohistochemistry assay. Our results showed that PCNA and C-myc positive cell densities were significantly higher in patient group than control group. P-53 positive cell density showed increasing trends in patients than control group. Moreover, we observed irregular hyperplasia in intimal tissue, fibrous connective tissue, and smooth muscle cell, accompanied by tissue degeneration (hyaloid degeneration and fibrinoid degeneration) and a large quantity of inflammatory cell infiltration. In conclusion, an overexpression of PCNA, C-myc, and a weak positive expression of P53 might launch the extremely irregular hepatic venous intimal hyperplasia, which is probably one of the etiologies of hepatic venous obstruction BCS.

Geomagnetic Field Distortion by a Solar Stream as a Mechanism for the Production of Polar Aurora and Electrojets

NASA Technical Reports Server (NTRS)

Kern, J. W.

1961-01-01

This paper describes a mechanism for charge separation in the geomagnetically trapped radiation which may account for some observed phenomena associated with the polar aurora and the electrojet current systems. The following development is proposed: given that there exist eastward or westward longitudinal gradients in the geomagnetic field resulting from distortion of the geomagnetic field by solar streams, if the trapped radiation is adiabatic in character, radial drift separation of positive and negative charged particles must occur. It follows that, for bounded or irregular distributions of plasma number density in such an adiabatic - drift region, electric fields will arise. The origin of such electric fields will not arrest the drift separation of the charged particles, but will contribute to exponential growth of irregularities in the trapped plasma density. An adiabatic acceleration mechanism is described, which is based on incorporating the electrostatic energy of the particle in the energy function for the particle. Direct consequences of polarization of the geomagnetically trapped radiation will be the polar electrojet current systems and the polar aurora.

Adjustments for the display of quantized ion channel dwell times in histograms with logarithmic bins.

PubMed

Stark, J A; Hladky, S B

2000-02-01

Dwell-time histograms are often plotted as part of patch-clamp investigations of ion channel currents. The advantages of plotting these histograms with a logarithmic time axis were demonstrated by, J. Physiol. (Lond.). 378:141-174), Pflügers Arch. 410:530-553), and, Biophys. J. 52:1047-1054). Sigworth and Sine argued that the interpretation of such histograms is simplified if the counts are presented in a manner similar to that of a probability density function. However, when ion channel records are recorded as a discrete time series, the dwell times are quantized. As a result, the mapping of dwell times to logarithmically spaced bins is highly irregular; bins may be empty, and significant irregularities may extend beyond the duration of 100 samples. Using simple approximations based on the nature of the binning process and the transformation rules for probability density functions, we develop adjustments for the display of the counts to compensate for this effect. Tests with simulated data suggest that this procedure provides a faithful representation of the data.

Subset Analysis of a Multicenter, Randomized Controlled Trial to Compare Magnifying Chromoendoscopy with Endoscopic Ultrasonography for Stage Diagnosis of Early Stage Colorectal Cancer.

PubMed

Yamada, Tomonori; Shimura, Takaya; Ebi, Masahide; Hirata, Yoshikazu; Nishiwaki, Hirotaka; Mizushima, Takashi; Asukai, Koki; Togawa, Shozo; Takahashi, Satoru; Joh, Takashi

2015-01-01

Our recent prospective study found equivalent accuracy of magnifying chromoendoscopy (MC) and endoscopic ultrasonography (EUS) for diagnosing the invasion depth of colorectal cancer (CRC); however, whether these tools show diagnostic differences in categories such as tumor size and morphology remains unclear. Hence, we conducted detailed subset analysis of the prospective data. In this multicenter, prospective, comparative trial, a total of 70 patients with early, flat CRC were enrolled from February 2011 to December 2012, and the results of 66 lesions were finally analyzed. Patients were randomly allocated to primary MC followed by EUS or to primary EUS followed by MC. Diagnoses of invasion depth by each tool were divided into intramucosal to slight submucosal invasion (invasion depth <1000 μm) and deep submucosal invasion (invasion depth ≥1000 μm), and then compared with the final pathological diagnosis by an independent pathologist blinded to clinical data. To standardize diagnoses among examiners, this trial was started after achievement of a mean κ value of ≥0.6 which was calculated from the average of κ values between each pair of participating endoscopists. Both MC and EUS showed similar diagnostic outcomes, with no significant differences in prediction of invasion depth in subset analyses according to tumor size, location, and morphology. Lesions that were consistently diagnosed as Tis/T1-SMS or ≥T1-SMD with both tools revealed accuracy of 76-78%. Accuracy was low in borderline lesions with irregular pit pattern in MC and distorted findings of the third layer in EUS (MC, 58.5%; EUS, 50.0%). MC and EUS showed the same limited accuracy for predicting invasion depth in all categories of early CRC. Since the irregular pit pattern in MC, distorted findings to the third layer in EUS and inconsistent diagnosis between both tools were associated with low accuracy, further refinements or even novel methods are still needed for such lesions. University hospital Medical Information Network Clinical Trials Registry UMIN 000005085.

Dynamics and distribution of black abalone populations at San Nicolas Island

USGS Publications Warehouse

VanBlaricom, Glenn R.; Hochberg, F.G.

1993-01-01

Dense populations of black abalones (Haliotis cracherodii Leach) were monitored in permanent intertidal plots at nine sites on San Nicolas Island from 1981 through 1990. Densities were essentially constant at all four sites along the north shore of the island throughout the study period. Densities at five sites along the south shore were more variable, possibly reflecting asynchronous variation in recruitment, mortality resulting from wave disturbance, and removal by people. Temporal variation of abalone densities apparently was not influenced by sea otters or abalone withering syndrome during this study. Abalones were strongly aggregated in space. Highest densities occurred in areas of irregular substrata, apparently as a result of preference for crevices and vertical faces. The locations of dense patches were persistent in time.

Investigation of traveling ionospheric disturbances

NASA Technical Reports Server (NTRS)

Grossi, M.; Estes, R. D.

1981-01-01

Maximum entropy power spectra of the ionospheric electron density were constructed to enable PINY to compare them with the power independently obtained by PINY with in situ measurements of ionospheric electron density and neutral species performed with instrumentation carried by the Atmospheric Explorer (AE) satellite. This comparison corroborated evidence on the geophysical reality of the alleged electron density irregularities detected by the ASTP dual frequency Doppler link. Roughly half of the localized wave structures which are confined to dimensions of 1800 km or less (as seen by an orbiting Doppler baseline) were found to be associated with the larger crest of the geomagnetic anomaly in the Southern (winter) Hemisphere in the morning. The observed nighttime structures are also associated with local peaks in the electron density.

[Changes in mammographic features of breast cancer--comparison with previous films].

PubMed

Matsunaga, T; Hagiwara, K; Kimura, K; Kusama, M

1992-11-25

Mammographic features of 87 breast cancer patients were studied in comparison with their previous survey films. Changes in the mammographic features included microcalicification (28 cases), tumor shadow (35 cases) and intratumorous microcalicifications (6 cases). Seven cases had several extremely faint calcifications on the previous films, and three of six cases with clustered and scattered microcalcifications that extended over an entire breast quadrant had increased in number, density and extent. Eight cases in which clustered microcalcifications had increased in number, density and extent suggested a relationship between the increase in the extent of microcalcifications and length of time between visits. In most cases with tumor shadow, a slight localized increase in mammary gland density, irregular margins and straightened trabeculae were overlooked because of breast density.

Polycystic ovary syndrome and prolactinoma association.

PubMed

Yavasoglu, Irfan; Kucuk, Mert; Coskun, Adil; Guney, Engin; Kadikoylu, Gurhan; Bolaman, Zahit

2009-01-01

Hyperprolactinemia is the most common pituitary hormone hypersecretion syndrome in both men and women. Polycystic ovary syndrome (PCOS) is one of the most common endocrinopathies affecting 5%-10% of reproductive age women. Here, we present a patient with irregular menses, obesity, hirsutism and infertility, and hyperprolactinemia who was diagnosed as PCOS and prolactinoma and admitted to our clinic. Prolactinoma and PCOS association is a rare condition. This 33-year-old woman was admitted to the internal medicine outpatient clinic for irregular menses, obesity, hirsutism and infertility, and hyperprolactinemia. Her laboratory results were as follows: prolactin was 74 ng/mL (normal range:1.8-20.3 ng/mL). Pelvic ultrasonography was correlated with polycystic ovary syndrome. Pituitary MRI showed 6x8 mm microadenoma at left half. Bromocriptine was started with 1.25 mg/day and increased to 5 mg/day. After six months of bromocriptine treatment her prolactin level was normal and no adenoma was detected in pituitary MRI. PCOS and prolactinoma association should be taken into account in PCOS cases with mild hyperprolactinoma.

A mathematical analysis of the ABCD criteria for diagnosing malignant melanoma

NASA Astrophysics Data System (ADS)

Lee, Hyunju; Kwon, Kiwoon

2017-03-01

The medical community currently employs the ABCD (asymmetry, border irregularity, color variegation, and diameter of the lesion) criteria in the early diagnosis of a malignant melanoma. Although many image segmentation and classification methods are used to analyze the ABCD criteria, it is rare to see a study containing mathematical justification of the parameters that are used to quantify the ABCD criteria. In this paper, we suggest new parameters to assess asymmetry, border irregularity, and color variegation, and explain the mathematical meaning of the parameters. The suggested parameters are then tested with 24 skin samples. The parameters suggested for the 24 skin samples are displayed in three-dimensional coordinates and are compared to those presented in other studies (Ercal et al 1994 IEEE Trans. Biomed. Eng. 41 837-45, Cheerla and Frazier 2014 Int. J. Innovative Res. Sci., Eng. Technol. 3 9164-83) in terms of Pearson correlation coefficient and classification accuracy in determining the malignancy of the lesions.

A sparse matrix-vector multiplication based algorithm for accurate density matrix computations on systems of millions of atoms

NASA Astrophysics Data System (ADS)

Ghale, Purnima; Johnson, Harley T.

2018-06-01

We present an efficient sparse matrix-vector (SpMV) based method to compute the density matrix P from a given Hamiltonian in electronic structure computations. Our method is a hybrid approach based on Chebyshev-Jackson approximation theory and matrix purification methods like the second order spectral projection purification (SP2). Recent methods to compute the density matrix scale as O(N) in the number of floating point operations but are accompanied by large memory and communication overhead, and they are based on iterative use of the sparse matrix-matrix multiplication kernel (SpGEMM), which is known to be computationally irregular. In addition to irregularity in the sparse Hamiltonian H, the nonzero structure of intermediate estimates of P depends on products of H and evolves over the course of computation. On the other hand, an expansion of the density matrix P in terms of Chebyshev polynomials is straightforward and SpMV based; however, the resulting density matrix may not satisfy the required constraints exactly. In this paper, we analyze the strengths and weaknesses of the Chebyshev-Jackson polynomials and the second order spectral projection purification (SP2) method, and propose to combine them so that the accurate density matrix can be computed using the SpMV computational kernel only, and without having to store the density matrix P. Our method accomplishes these objectives by using the Chebyshev polynomial estimate as the initial guess for SP2, which is followed by using sparse matrix-vector multiplications (SpMVs) to replicate the behavior of the SP2 algorithm for purification. We demonstrate the method on a tight-binding model system of an oxide material containing more than 3 million atoms. In addition, we also present the predicted behavior of our method when applied to near-metallic Hamiltonians with a wide energy spectrum.

A review: flexible, stretchable multifunctional sensors and actuators for heart arrhythmia therapy

NASA Astrophysics Data System (ADS)

Kang, Seung-Jo; Pak, James Jungho

2017-12-01

Cardiovascular disease is a very serious disease which results in about 30% of all global mortality. Atrial fibrillation (AF) causes rapid and irregular contractions resulting in stroke and cardiac arrest. AF is caused by abnormality of the heartbeat controlling electrical signal. Catheter ablation (CA) is often used to treat and remove the abnormal electrical source from the heart but it has limitations in sensing capability and spatial coverage. To overcome the limitations of the CA, new devices for improving the spatial capability have been reported. One of the most impressive methods is wrapping the heart surface with a flexible/stretchable film with an array of high-density multifunctional micro-sensors and actuators. With this technique, the overall heart surface may be diagnosed in real time and the AF may be treated much more effectively. The data acquisition from the array of multifunctional sensors is also very important for making the new devices useful. To operate the implanted device system, a battery is mostly used and it should be avoided to replace the battery by surgery. Therefore, various energy harvesting techniques or wireless energy transfer techniques to continuously feed the power to the system are under investigation. The development of these technologies was reviewed, and the current level of technology was reviewed and summarized.

Effects of modification of the polar ionosphere with high-power short-wave extraordinary-mode HF waves produced by the spear heating facility

NASA Astrophysics Data System (ADS)

Borisova, T. D.; Blagoveshchenskaya, N. F.; S. Kalishin, A.; Oksavik, K.; Baddelley, L.; K. Yeoman, T.

2012-06-01

We present the results of modifying the F2 layer of the polar ionosphere experimentally with highpower HF extraordinary-mode waves. The experiments were performed in October 2010 using the short-wave SPEAR heating facility (Longyearbyen, Spitsbergen). To diagnose the effects of high-power HF waves by the aspect-scattering method in a network of diagnostic paths, we used the short-wave Doppler radar CUTLASS (Hankasalmi, Finland) and the incoherent scatter radar ESR (Longyearbyen, Spitsbergen). Excitation of small-scale artificial ionospheric irregularities was revealed, which were responsible for the aspect and backward scattering of the diagnostic signals. The measurements performed by the ESR incoherent scatter radar simultaneously with the heating demonstrated changes in the parameters of the ionospheric plasma, specifically, an increase in the electron density by 10-25 % and an increase in the electron temperature by 10-30 % at the altitudes of the F2 layer, as well as formation of sporadic ionization at altitudes of 140-180 km (below the F2 layer maximum). To explain the effects of ionosphere heating with HF extraordinary-mode waves, we propose a hypothesis of transformation of extraordinary electromagnetic waves to ordinary in the anisotropic, smoothly nonuniform ionosphere.

Zonal Drift Variations and Suppression of Ionospheric Scintillation During St. Patrick's Day Storm Observed by Pingtung SCINDA Station in Taiwan

NASA Astrophysics Data System (ADS)

Su, S. Y.; Nayak, C.; Tsai, L. C.; Caton, R. G.; Groves, K. M.

2016-12-01

Variations of zonal drift and ionospheric VHF scintillations observed by a SCINDA station in Southern Taiwan during the St. Patrick's day geomagnetic storm are studied. Although scintillations were observed for 6 consecutive days before the storm, they were absence during the storm period. Data from VHF receivers, ionosonde and in situ plasma density observations from ESA's SWARM constellation are used to study the ionospheric irregularity/scintillation events in the Taiwanese sector to compare with what happened in the Indian sectors. The absence of scintillation in the Taiwanese sector during the storm period seems to be caused by a reduced pre-reversal enhancement (PRE) electric field from a westward prompt-penetration electric field (PPEF) during the storm. A low post-sunset ionosphere thus becomes unfavorable for the Rayleigh-Taylor instability to occur. On the contrary, the PPEFs were found to strongly enhance the PRE electric field in the Indian sector to cause the ionospheric irregularities/scintillations in the post-sunset sector. Zonal drift variations during the storm time are also discussed in conjunction with the irregularity/scintillation occurrences.

A computer model for high-latitude phase scintillation based on wideband satellite data from Poker Flat

NASA Astrophysics Data System (ADS)

Fremouw, E. J.; Lansinger, J. M.

1981-02-01

A mathematical model has been developed for describing plasma-density irregularities responsible for radiowave scintillation produced in the auroral ionosphere, and the model has been committed to an applications-oriented computer code, WBMOD. The model characterizes the three-dimensional configuration, gradient sharpness, and height-integrated strength of irregularities represented by a power-law spatial spectrum as functions of geomagnetic latitude, time of day, sunspot number, and planetary geomagnetic activity index. Program WBMOD permits calculation of the power-law index and spectral strength (at a fluctuation frequency of 1 Hz) of phase scintillation, together with scintillation indices (variances) for phase and intensity, using a phase-screen scattering theory. The model has been calibrated and iteratively tested against phase-scintillation data from the DNA Wideband Satellite Experiment, collected at Poker Flat, Alaska. It does not account for seasonal variations in high-latitude scintillation observed in other longitude sectors. The program contains a model for middle-latitude and equatorial irregularities as well as for auroral latitudes, but only the latter has been tested extensively against high-quality scintillation data.

A 27-year-old woman diagnosed as polycystic ovary syndrome associated with Graves' disease.

PubMed

Jung, Jung Hwa; Hahm, Jong Ryeal; Jung, Tae Sik; Kim, Hee Jin; Kim, Ho Soo; Kim, Sungsu; Kim, Soo Kyoung; Lee, Sang Min; Kim, Deok Ryong; Choi, Won Jun; Seo, Yeong Mi; Chung, Soon Il

2011-01-01

Polycystic ovary syndrome (PCOS) and Graves' disease are the common causes of menstrual irregularity leading to infertility in women of child-bearing age. A 21-year-old female patient visited us with complaints of oligomenorrhea and hand tremor. She was diagnosed as having PCOS and hyperthyroid Graves' disease, simultaneously. She had low body weight (BMI: 16.4 kg/m(2)), mild hirsutism, and thyrotoxicosis. The patient was treated with anti-thyroid drug and beta-blocker for about two years, and then recovered to normal thyroid function. Although some studies have suggested a connection between PCOS and autoimmune thyroiditis, no study indicated that PCOS is associated with Graves' disease until now. Here, we describe the first case report of a lean woman with normal insulin sensitivity presenting PCOS and Graves' disease simultaneously.

Artificial plasma cusp generated by upper hybrid instabilities in HF heating experiments at HAARP

NASA Astrophysics Data System (ADS)

Kuo, Spencer; Snyder, Arnold

2013-05-01

High Frequency Active Auroral Research Program digisonde was operated in a fast mode to record ionospheric modifications by the HF heating wave. With the O mode heater of 3.2 MHz turned on for 2 min, significant virtual height spread was observed in the heater off ionograms, acquired beginning the moment the heater turned off. Moreover, there is a noticeable bump in the virtual height spread of the ionogram trace that appears next to the plasma frequency (~ 2.88 MHz) of the upper hybrid resonance layer of the HF heating wave. The enhanced spread and the bump disappear in the subsequent heater off ionograms recorded 1 min later. The height distribution of the ionosphere in the spread situation indicates that both electron density and temperature increases exceed 10% over a large altitude region (> 30 km) from below to above the upper hybrid resonance layer. This "mini cusp" (bump) is similar to the cusp occurring in daytime ionograms at the F1-F2 layer transition, indicating that there is a small ledge in the density profile reminiscent of F1-F2 layer transitions. Two parametric processes exciting upper hybrid waves as the sidebands by the HF heating waves are studied. Field-aligned purely growing mode and lower hybrid wave are the respective decay modes. The excited upper hybrid and lower hybrid waves introduce the anomalous electron heating which results in the ionization enhancement and localized density ledge. The large-scale density irregularities formed in the heat flow, together with the density irregularities formed through the parametric instability, give rise to the enhanced virtual height spread. The results of upper hybrid instability analysis are also applied to explain the descending feature in the development of the artificial ionization layers observed in electron cyclotron harmonic resonance heating experiments.

The Vector Electric Field Investigation on the C/NOFS Satellite

NASA Technical Reports Server (NTRS)

Pfaff, R.; Acuna, M.; Kujawski, J.; Fourre, R.; Uribe, P.; Hunsaker, F.; Rowland, D.; Le, G.; Farrell, W.; Maynard, N.;

Gamma-aminobutyric acid (GABA) and neuropeptides in neural areas mediating motion-induced emesis

NASA Technical Reports Server (NTRS)

Damelio, F.; Daunton, Nancy G.; Fox, Robert A.

1991-01-01

Immunocytochemical methods were employed to localize the neurotransmitter amino acid gamma-aminobutyric acid and the neuropeptides substance P and Met-enkephalin in the area postrema (AP), area subpostrema (ASP), nucleus of the tractus solitarius (NTS), dorsal motor nucleus of the vagus nerve (DMNV), and lateral vestibular nucleus (LVN). Glutamic acid decarboxylase immunoreactive (GAD-IR) terminals and fibers were observed in the AP and particularly in the ASP. A gradual decrease in the density of terminals was seen towards the solitary complex. The DMNV revealed irregularly scattered GAD-IR terminals within the neuropil or closely surrounding neuronal cell bodies. The LVN, particularly the dorsal division, showed numerous axon terminals which were mostly localize around large neurons and their proximal dendrites. Substance P immunoreactive (SP-IR) terminals and fibers showed high density in the solitary complex, in particular within the lateral division. The ASP showed medium to low density of SP-IR fibers and terminals. The AP exhibited a small number of fibers and terminals irregularly distributed. The DMNV revealed a high density of SP-IR terminals and fibers that were mainly concentrated in the periphery. Very few terminals were detected in the LVN. Met-enkephalin immunoreactive (Met-Enk-IR) fibers and terminals showed high density and uniform distribution in the DMNV. Scattered terminals and fibers were observed in the AP, ASP, and NTS (particularly the lateral division). The very few fibers were observed in the LVN surrounded the neuronal cell bodies. The present report is part of a study designed to investigate the interaction between neuropeptides and conventional neurotransmitters under conditions producing motion sickness and in the process of sensory-motor adaptation.

CT of abdominal tuberculosis

DOE Office of Scientific and Technical Information (OSTI.GOV)

Epstein, B.M.; Mann, J.H.

1982-11-01

Intraabdominal tuberculosis (TB) presents with a wide variety of clinical and radiologic features. Besides the reported computed tomographic (CT) finding of high-density ascites in tuberculous peritonitis, this report describes additional CT features highly suggestive of abdominal tuberculosis in eight cases: (1) irregular soft-tissue densities in the omental area; (2) low-density masses surrounded by thick solid rims; (3) a disorganized appearance of soft-tissue densities, fluid, and bowel loops forming a poorly defined mass; (4) low-density lymph nodes with a multilocular appearance after intravenous contrast administration; and (5) possibly high-density ascites. The differential diagnosis of these features include lymphoma, various forms ofmore » peritonitis, peritoneal carcinomatosis, and peritoneal mesothelioma. It is important that the CT features of intraabdominal tuberculosis be recognized in order that laparotomy be avoided and less invasive procedures (e.g., laparoscopy, biopsy, or a trial of antituberculous therapy) be instituted.« less

Simulations of neutral wind shear effect on the equatorial ionosphere irregularities

NASA Astrophysics Data System (ADS)

Kim, J.; Chagelishvili, G.; Horton, W.

2005-12-01

We present numerical calculations of the large-scale electron density driven by the gradient drift instability in the daytime equatorial electrojet. Under two-fluid theory the linear analysis for kilometer scale waves lead to the result that all the perturbations are transformed to small scales through linear convection by shear and then damped by diffusion. The inclusion of the nonlinearity enables inverse energy cascade to provide energy to long scale. The feedback between velocity shear and nonlinearity keeps waves growing and leads to the turbulence. In strongly turbulent regime, the nonlinear states are saturated [1]. Since the convective nonlinearities are isotropic while the interactions of velocity shear with waves are anisotropic, the feedback do not necessarily enable waves to grow. The growth of waves are highly variable on k-space configuration [2]. Our simulations show that the directional relationship between vorticity of irregularities and shear are one of key factors. Thus during the transient period, the irregularities show the anisotropy of the vorticity power spectrum. We report the evolution of the power spectrum of the vorticity and density of irregularties and its anistropic nature as observed. The work was supported in part by the Department of NSF Grant ATM-0229863 and ISTC Grant G-553. C. Ronchi, R.N. Sudan, and D.T. Farley. Numerical simulations of large-scale plasma turbulece in teh day time equatorial electrojet. J. Geophys. Res., 96:21263--21279, 1991. G.D. Chagelishvili, R.G. Chanishvili, T.S. Hristov, and J.G. Lominadze. A turbulence model in unbounded smooth shear flows : The weak turbulence approach. JETP, 94(2):434--445, 2002.

Study of Sun-Earth interactions using equatorial VHF scintillation in the Indian region

NASA Astrophysics Data System (ADS)

Banola, Sridhar

Plasma density irregularities in the ionosphere (associated with ESF, plasma bubbles and Spo-radic E layers) cause scintillations in various frequency ranges. VHF radio wave scintillation technique is extensively used to study plasma density irregularities of sub-kilometre size . Ef-fects of magnetic and solar activity on ionospheric irregularities are studied so as to ascertain their role in the space weather of the near earth environment in space. Indian Institute of Ge-omagnetism operated a ground network of 13 stations monitoring amplitude scintillations on 244/251 MHz (FLEETSAT 73° E) signals in placecountry-regionIndia for more than a decade under AICPITS. At present VHF scintillation is being recorded at Mumbai by monitoring 251 MHz signal transmitted by geostationary satellite UFO2(71.2 E). sampling at 20 Hz. During CAWSES campaign (March-April 2006, low sunspot period) occurrence of daytime scintilla-tions was observed higher than the nighttime scintillations. This could be due to the fact that during low sunspot years occurrence of spread-F is limited to a narrow latitude region near the dip equator. To study solar cycle association of scintillations, long series of simultaneous amplitude scintillation data for period Jan 1989 to Dec 2000 at Indian low-latitude stations Tirunelveli/Trivandrum, close to dip equator, Pondicherry/Karur, located at the fringe of elec-trojet, Mumbai (dip lat. 13.5o N), a temperate station and Ujjain (dip lat. 18.6o N), close to anomaly crest region are utilized. Nighttime scintillation occurrence is solar activity dependent. Equatorial scintillations are inhibited with increase in geomagnetic activity.

Evaluation of ovarian reserve tests in women with systemic lupus erythematosus.

PubMed

Ulug, Pasa; Oner, Gokalp; Kasap, Burcu; Akbas, Emin Murat; Ozcicek, Fatih

2014-07-01

Impact of systemic lupus erythematosus (SLE) on fertility may be negative, and ovarian function can be also reduced by autoimmune oophoritis. In this article, we evaluated the ovarian reserve of pre-menopausal women firstly diagnosed with systemic lupus erythematosus (SLE). This was a prospective controlled study which included twenty women with SLE and twenty healthy women as controls in the reproductive age. Basal levels of FSH, estradiol (E2), and LH on cycle day 3 were measured. All participants underwent transvaginal ultrasonographic examination on the third day of their menstrual periods for the determination of ovarian volume (OV) and total antral follicle count (AFC). A significant difference in FSH, LH, and E2 levels was observed between women with SLE and healthy controls. There was a statistically significant reduction in total AFC and OV in SLE group. Age was associated negatively with AFC, whereas positively with FSH and LH. Menstrual irregularity was significantly higher in SLE patients than control. AFC was the most reliable test to show the menstrual irregularity and negatively correlated each other in women with SLE. In this preliminary study, the first in SLE patients, we illustrated that women with SLE had lower ovarian reserves and higher menstrual irregularity compared with healthy controls according to hormonal and ultrasonographical evaluation. © 2014 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Eccentricity and fluting in young–growth western hemlock in Oregon.

Treesearch

Ryan Singleton; Dean S. DeBell; David D. Marshall; Barbara L. Gartner

2004-01-01

Stem irregularities can influence estimates of tree and stand attributes, efficiency of manufacturing processes, and quality of wood products. Eccentricity and fluting were characterized in young, managed western hemlock stands in the Oregon Coast Range. Sixty-one trees were selected from pure western hemlock stands across a range of age, site, and densities. The trees...

Saturn: Origin and composition of its inner moons and rings

NASA Technical Reports Server (NTRS)

Prentice, A. J. R.

1980-01-01

The contraction of the primitive protosaturnian cloud, using ideas of supersonic turbulent convection was modeled. The model suggested that each of Saturn's inner moons, excepting Rhea, condensed above the ice-point of water and consists primarily of hydrous magnesium silicates. The satellite mean densities steadily increase towards the planet and the rocky moons are irregular in shape.

Investigations of the ionospheric using radio signals from artificial satellites

NASA Technical Reports Server (NTRS)

Titheridge, J. E.

1973-01-01

The occurrence and characteristics of ionospheric irregularities in medium latitudes and in polar regions were measured using radio signals from artificial satellites. Ionospheric changes during quiet and disturbed conditions were also measured. Electron density, elevation angle, and amplitude and frequency of these high frequency signals were determined as well as the direction of their arrival.

Low and Mid-Latitude Ionospheric Irregularities Studies Using TEC and Radio Scintillation Data from the CITRIS Radio Beacon Receiver in Low-Earth-Orbit

NASA Astrophysics Data System (ADS)

Siefring, C. L.; Bernhardt, P. A.; Huba, J.; Krall, J.; Roddy, P. A.

2009-12-01

Unique data on ionospheric plasma irregularities from the Naval Research Laboratory (NRL) CITRIS (Scintillation and TEC Receiver in Space) instrument will be presented. CITRIS is a multi-band receiver that recorded TEC (Total Electron Content) and radio scintillations from Low-Earth Orbit (LEO) on STPSat1. The 555+/5 km altitude 35° inclination orbit covers low and mid-latitudes. The measurements require propagation from a transmitter to a receiver through the F-region plasma. CITRIS used both 1) satellite beacons in LEO, such as the NRL CERTO (Coherent Electromagnetic Radio TOmography) beacons and 2) the global network of ground-based DORIS (Doppler Orbitography and Radiopositioning Integrated by Satellite) beacons. The TEC measurements allow for tracking of ionospheric disturbances and irregularities while the measurements of scintillations can simultaneously characterize their effects. CITRIS was operated in a complementary fashion with the C/NOFS (Communication/Navigations Outages Forecasting System) satellite during most of its first year of operations. C/NOFS carries a three-frequency 150/400/1067 MHz CERTO beacon and is dedicated to the study of Spread-F. In the case of Spread-F, ionospheric irregularities start with large scale size density gradients (100s of km) and cascade through complex processes to short scale sizes (10s of meters). It is typically the 100m-1km scale features that harm communication and navigation systems through scintillations. A multi-sensor approach is needed to completely understand this complex system, such as, the combination of CITRIS remote radio sensing and C/NOFS in-situ data. Several types of irregularities have been studied including Spread-F and the newly discovered dawn-side depletions. Comparisons with the physics based SAMI3 model are being performed to help our understanding of the morphology of the irregularities.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Semiz, İbrahim; Kazım Çamlıbel, A., E-mail: ibrahim.semiz@boun.edu.tr, E-mail: kazim.camlibel@boun.edu.tr

We try to reconstruct the scale factor a(t) of the universe from the SNe Ia data, i.e. the luminosity distance d{sub L}(z), using only the cosmological principle and the assumption that gravitation is governed by a metric theory. In our hence model-independent, or cosmographic study, we fit functions to d{sub L}(z) rather than a(t), since d{sub L}(z) is what is measured. We find that the acceleration history of the universe cannot be reliably determined in this approach due to the irregularity and parametrization-dependence of the results. However, adding the GRB data to the dataset cures most of the irregularities, atmore » the cost of compromising the model-independent nature of the study slightly. Then we can determine the redshift of transition to cosmic acceleration as z{sub t} ∼ 0.50 ± 0.09 for a flat universe (larger for positive spatial curvature).If Einstein gravity (GR) is assumed, we find a redshift at which the density of the universe predicted from the d{sub L}(z) data is independent of curvature. We use this point to derive an upper limit on matter density, hence a lower limit on the density of dark energy. While these limits do not improve the generally accepted ones, they are derived only using the d{sub L}(z) data.« less

DE/ISIS conjunction comparisons of high-latitude electron density features

NASA Technical Reports Server (NTRS)

Hoegy, Walter R.; Benson, Robert F.

1988-01-01

This paper presents a comparison between the ISIS-1 and -2 topside sounder measurements of electron number density, N(e), with the in situ ion and N(e) measurements by the Langmuir probe aboard the Dynamics Explorer 2 (DE 2) during four high-latitude ISIS/DE magnetic field-aligned conjunctions. The ISIS-derived N(e) values, even at the greatest distance from the sounder, were found to agree with the Langmuir probe measurements to within about 30 percent over a density range of more than two decades on three of the four comparisons; the fourth comparison which included data with strong N(e) irregularities, showed a difference of 60 percent.

The teenager with palpitations.

PubMed

Sedaghat-Yazdi, Farshad; Koenig, Peter R

2014-02-01

Palpitations can result from cardiac awareness (increased conscious perception of the heart beating) or from a fast or irregular cardiac rhythm. Most causes for palpitations in the teenager can be diagnosed with minimal testing. Patients with an abnormal ECG, non-sinus tachycardia, abnormal cardiac examination, concerning family history, or palpitations associated with activity or syncope should be referred to a pediatric cardiologist. This article discusses the evaluation, testing, and management of teenagers with palpitations. It also provides a general guideline for referral for subspecialty evaluation. Copyright © 2014 Elsevier Inc. All rights reserved.

Proctalgia fugax: would you recognize it?

PubMed

Babb, R R

1996-04-01

Proctalgia fugax is characterized by sudden and sometimes severe rectal pain that occurs by day or night at irregular intervals. The pain results from dysfunction of the internal anal sphincter. Proctalgia fugax has a uniform clinical picture, and it can be easily diagnosed when recognized. The patient can be assured that nothing serious is wrong. Expensive tests, such as computed tomography or magnetic resonance imaging of the pelvis, are not required. Treatment may be difficult, but if the attacks of pain are numerous and severe,, a calcium channel blocker such as nifedipine (Adalat, Procardia) should be tried.

Studies of small-scale plasma inhomogeneities in the cusp ionosphere using sounding rocket data

NASA Astrophysics Data System (ADS)

Chernyshov, Alexander A.; Spicher, Andres; Ilyasov, Askar A.; Miloch, Wojciech J.; Clausen, Lasse B. N.; Saito, Yoshifumi; Jin, Yaqi; Moen, Jøran I.

2018-04-01

Microprocesses associated with plasma inhomogeneities are studied on the basis of data from the Investigation of Cusp Irregularities (ICI-3) sounding rocket. The ICI-3 rocket is devoted to investigating a reverse flow event in the cusp F region ionosphere. By numerical stability analysis, it is demonstrated that inhomogeneous-energy-density-driven (IEDD) instability can be a mechanism for the excitation of small-scale plasma inhomogeneities. The Local Intermittency Measure (LIM) method also applied the rocket data to analyze irregular structures of the electric field during rocket flight in the cusp. A qualitative agreement between high values of the growth rates of the IEDD instability and the regions with enhanced LIM is observed. This suggests that IEDD instability is connected to turbulent non-Gaussian processes.

Climatology of GPS signal loss observed by Swarm satellites

NASA Astrophysics Data System (ADS)

Xiong, Chao; Stolle, Claudia; Park, Jaeheung

2018-04-01

By using 3-year global positioning system (GPS) measurements from December 2013 to November 2016, we provide in this study a detailed survey on the climatology of the GPS signal loss of Swarm onboard receivers. Our results show that the GPS signal losses prefer to occur at both low latitudes between ±5 and ±20° magnetic latitude (MLAT) and high latitudes above 60° MLAT in both hemispheres. These events at all latitudes are observed mainly during equinoxes and December solstice months, while totally absent during June solstice months. At low latitudes the GPS signal losses are caused by the equatorial plasma irregularities shortly after sunset, and at high latitude they are also highly related to the large density gradients associated with ionospheric irregularities. Additionally, the high-latitude events are more often observed in the Southern Hemisphere, occurring mainly at the cusp region and along nightside auroral latitudes. The signal losses mainly happen for those GPS rays with elevation angles less than 20°, and more commonly occur when the line of sight between GPS and Swarm satellites is aligned with the shell structure of plasma irregularities. Our results also confirm that the capability of the Swarm receiver has been improved after the bandwidth of the phase-locked loop (PLL) widened, but the updates cannot radically avoid the interruption in tracking GPS satellites caused by the ionospheric plasma irregularities. Additionally, after the PLL bandwidth increased larger than 0.5 Hz, some unexpected signal losses are observed even at middle latitudes, which are not related to the ionospheric plasma irregularities. Our results suggest that rather than 1.0 Hz, a PLL bandwidth of 0.5 Hz is a more suitable value for the Swarm receiver.

Low-Latitude Ionospheric Density Irregularities and Associated Scintillations Investigated by Combining COSMIC RO and Ground-Based Global Positioning System Observations Over a Solar Active Period

NASA Astrophysics Data System (ADS)

Yang, Zhe; Liu, Zhizhao

2018-05-01

This study for the first time presents a locally integrated analysis of occurrences of ionospheric E and F region irregularities/scintillations in southeast China, by employing radio occultation (RO) profile data retrieved from Constellation Observing System for Meteorology, Ionosphere, and Climate (COSMIC) satellites and observations from a ground-based Global Navigation Satellite System receiver over a solar active period from 2014 to 2015. Their occurrences in both nighttime and daytime were examined by using both amplitude scintillation index (S4) and the rate of change of total electron content index. It is found that (1) F region irregularities occurred predominantly during 20-03 local time (LT) and exhibited maximum (minimum) during equinoxes (solstices) and equinoctial (solstice) asymmetry. Their geographic mapping reveals the maximum occurrence in the westward tilted structure of equatorial plasma bubbles. In addition, the altitude-time variations indicate that their occurrences at higher altitudes were prevailing at 20-22 LT. (2) The E region irregularities were found prominently during 15-00 LT at altitudes of 90-110 km with an even geographic distribution. Their occurrences with maximum in summer (May-August) were distinctly detected by RO observations but insignificantly by ground-based observations. (3) By examining simultaneous observations of E and F region irregularities, it is found that they appeared absent during 21-00 LT and predominant after midnight. This could be related to the weakening/disruption of sporadic E (Es) layers during the development of equatorial plasma bubbles. A sign of coupling of E and F regions during nighttime is likely revealed from RO profile data.

Fatal familial insomnia presenting with agrypnia excitata and very low atonia index level: A case report and literature review.

PubMed

Yang, Tae-Won; Park, Byeongsu; Kim, Keun Tae; Jun, Jin-Sun; Kim, Young-Soo; Lee, Soon-Tae; Jung, Keun-Hwa; Chu, Kon; Lee, Sang Kun; Jung, Ki-Young

2018-05-01

Fatal familial insomnia (FFI) is a human prion disease that is characterized by sleep-wake cycle deterioration, loss of slow-wave sleep, and motor overactivation over the daily 24-hour period. Here, we report the case of a 57-year-old man who had an irregular sleep-wake cycle and exhibited frequent movements and vocalizations during sleep. Video-polysomnography showed disrupted sleep structure, rapid alternation between sleep stages, and an absence of sleep spindles and slow-wave sleep. Moreover, body movements persisted throughout the entire sleep period, including rapid eye movement (REM) sleep. The atonia index was very low (<0.025) during REM sleep. Genetic testing revealed a prion protein gene mutation at codon 178, and the patient was diagnosed with FFI. We tried to treat with amantadine, doxycycline, and immunotherapies, but the disease progressed. Sleep disturbance is the most frequent and essential symptom of FFI. FFI is difficult to diagnose due to the low sensitivity of diagnostic tools. Diagnoses can be further supported by better knowledge of typical polysomnographic findings.

The gravitational potential of a homogeneous polyhedron or don't cut corners

NASA Technical Reports Server (NTRS)

Werner, Robert A.

1994-01-01

A polyhedron can model irregularly shaped objects such as asteroids, comet nuclei, and small planetary satellites. With minor effort, such a model can incorporate important surface features such as large craters. Here we develop closed-form expressions for the exterior gravitational potential and acceleration components due to a constant-density polyhedron. An equipotential surface of Phobos is illustrated.

46 CFR 164.009-17 - Density measurement.

Code of Federal Regulations, 2014 CFR

2014-10-01

...) If the sample is a solid material, a specimen that has a length of 305 mm, a width of 305 mm, and thickness equal to that of the sample is prepared. The length and width are measured to the nearest 0.80 mm and the thickness to the nearest 0.25 mm. Allowance is made for any irregularity in the surfaces of...

46 CFR 164.009-17 - Density measurement.

Code of Federal Regulations, 2011 CFR

2011-10-01

...) If the sample is a solid material, a specimen that has a length of 305 mm, a width of 305 mm, and thickness equal to that of the sample is prepared. The length and width are measured to the nearest 0.80 mm and the thickness to the nearest 0.25 mm. Allowance is made for any irregularity in the surfaces of...

46 CFR 164.009-17 - Density measurement.

Code of Federal Regulations, 2013 CFR

2013-10-01

...) If the sample is a solid material, a specimen that has a length of 305 mm, a width of 305 mm, and thickness equal to that of the sample is prepared. The length and width are measured to the nearest 0.80 mm and the thickness to the nearest 0.25 mm. Allowance is made for any irregularity in the surfaces of...

46 CFR 164.009-17 - Density measurement.

Code of Federal Regulations, 2012 CFR

2012-10-01

...) If the sample is a solid material, a specimen that has a length of 305 mm, a width of 305 mm, and thickness equal to that of the sample is prepared. The length and width are measured to the nearest 0.80 mm and the thickness to the nearest 0.25 mm. Allowance is made for any irregularity in the surfaces of...

Ionospheric modifications in high frequency heating experiments

NASA Astrophysics Data System (ADS)

Kuo, Spencer P.

2015-01-01

Featured observations in high-frequency (HF) heating experiments conducted at Arecibo, EISCAT, and high frequency active auroral research program are discussed. These phenomena appearing in the F region of the ionosphere include high-frequency heater enhanced plasma lines, airglow enhancement, energetic electron flux, artificial ionization layers, artificial spread-F, ionization enhancement, artificial cusp, wideband absorption, short-scale (meters) density irregularities, and stimulated electromagnetic emissions, which were observed when the O-mode HF heater waves with frequencies below foF2 were applied. The implication and associated physical mechanism of each observation are discussed and explained. It is shown that these phenomena caused by the HF heating are all ascribed directly or indirectly to the excitation of parametric instabilities which instigate anomalous heating. Formulation and analysis of parametric instabilities are presented. The results show that oscillating two stream instability and parametric decay instability can be excited by the O-mode HF heater waves, transmitted from all three heating facilities, in the regions near the HF reflection height and near the upper hybrid resonance layer. The excited Langmuir waves, upper hybrid waves, ion acoustic waves, lower hybrid waves, and field-aligned density irregularities set off subsequent wave-wave and wave-electron interactions, giving rise to the observed phenomena.

Lymph microvascularization as a prognostic indicator in neuroblastoma.

PubMed

Tadeo, Irene; Gamero-Sandemetrio, Esther; Berbegall, Ana P; Gironella, Marta; Ritort, Félix; Cañete, Adela; Bueno, Gloria; Navarro, Samuel; Noguera, Rosa

2018-05-25

Neuroblastoma is the most common extra-cranial solid pediatric cancer and causes approximately 15% of all childhood deaths from cancer. Although lymphatic vasculature is a prerequisite for the maintenance of tissue fluid balance and immunity in the body, little is known about the relationship between lymphatic vascularization and prognosis in neuroblastoma. We used our previously-published custom-designed tool to close open-outline vessels and measure the density, size and shape of all lymphatic vessels and microvascular segments in 332 primary neuroblastoma contained in tissue microarrays. The results were correlated with clinical and biological features of known prognostic value and with risk of progression to establish histological lymphatic vascular patterns associated with unfavorable histology. A high proportion of irregular intermediate lymphatic capillaries and irregular small collector vessels were present in tumors from patients with metastatic stage, undifferentiating neuroblasts and/or classified in the high risk. In addition, a higher lymphatic microvascularization density was found to be predictive of overall survival. Our findings show the crucial role of lymphatic vascularization in metastatic development and maintenance of tumor tissue homeostasis. These patterns may therefore help to indicate more accurate pre-treatment risk stratification and could provide candidate targets for novel therapies.

Irregular oscillatory patterns in the early-time region of coherent phonon generation in silicon

NASA Astrophysics Data System (ADS)

Watanabe, Yohei; Hino, Ken-ichi; Hase, Muneaki; Maeshima, Nobuya

2017-09-01

Coherent phonon (CP) generation in an undoped Si crystal is theoretically investigated to shed light on unexplored quantum-mechanical effects in the early-time region immediately after the irradiation of ultrashort laser pulses. We examine time signals attributed to an induced charge density of an ionic core, placing the focus on the effects of the Rabi frequency Ω0 c v on the signals; this frequency corresponds to the peak electric-field of the pulse. It is found that at specific Ω0 c v's, where the energy of plasmon caused by photoexcited carriers coincides with the longitudinal-optical phonon energy, the energetically resonant interaction between these two modes leads to striking anticrossings, revealing irregular oscillations with anomalously enhanced amplitudes in the observed time signals. Also, the oscillatory pattern is subject to the Rabi flopping of the excited carrier density that is controlled by Ω0 c v. These findings show that the early-time region is enriched with quantum-mechanical effects inherent in the CP generation, though experimental signals are more or less masked by the so-called coherent artifact due to nonlinear optical effects.

Vibration responses of h-BN sheet to charge doping and external strain

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yang, Wei; Yang, Yu; Zheng, Fawei

2013-12-07

Based on density functional theory and density functional perturbation theory calculations, we systematically investigate the vibration responses of h-BN sheet to charge doping and external strains. It is found that under hole doping, the phonon frequencies of the ZO and TO branches at different wave vector q shift linearly with different slopes. Under electron doping, although the phonon frequencies shift irregularly, the shifting values are different at different phonon wave vectors. Interestingly, we find that external strain can restrain the irregular vibration responses of h-BN sheet to electron doping. The critical factor is revealed to be the relative position ofmore » the nearly free electron and boron p{sub z} states of h-BN sheet. Under external strains, the vibration responses of h-BN sheet are also found to be highly dependent on the phonon branches. Different vibration modes at different q points are revealed to be responsible for the vibration responses of h-BN sheet to charge doping and external strain. Our results point out a new way to detect the doping or strain status of h-BN sheet by measuring the vibration frequencies at different wave vector.« less

Simulations of Atmospheric Neutral Wave Coupling to the Ionosphere

NASA Astrophysics Data System (ADS)

Siefring, C. L.; Bernhardt, P. A.

2005-12-01

The densities in the E- and F-layer plasmas are much less than the density of background neutral atmosphere. Atmospheric neutral waves are primary sources of plasma density fluctuations and are the sources for triggering plasma instabilities. The neutral atmosphere supports acoustic waves, acoustic gravity waves, and Kelvin Helmholtz waves from wind shears. These waves help determine the structure of the ionosphere by changes in neutral density that affect ion-electron recombination and by neutral velocities that couple to the plasma via ion-neutral collisions. Neutral acoustic disturbances can arise from thunderstorms, chemical factory explosions and intentional high-explosive tests. Based on conservation of energy, acoustic waves grow in amplitude as they propagate upwards to lower atmospheric densities. Shock waves can form in an acoustic pulse that is eventually damped by viscosity. Ionospheric effects from acoustic waves include transient perturbations of E- and F-Regions and triggering of E-Region instabilities. Acoustic-gravity waves affect the ionosphere over large distances. Gravity wave sources include thunderstorms, auroral region disturbances, Space Shuttle launches and possibly solar eclipses. Low frequency acoustic-gravity waves propagate to yield traveling ionospheric disturbances (TID's), triggering of Equatorial bubbles, and possible periodic structuring of the E-Region. Gravity wave triggering of equatorial bubbles is studied numerically by solving the equations for plasma continuity and ion velocity along with Ohms law to provide an equation for the induced electric potential. Slow moving gravity waves provide density depressions on bottom of ionosphere and a gravitational Rayleigh-Taylor instability is initiated. Radar scatter detects field aligned irregularities in the resulting plasma bubble. Neutral Kelvin-Helmholtz waves are produced by strong mesospheric wind shears that are also coincident with the formation of intense E-layers. An atmospheric model for periodic structures with Kelvin-Helmholtz (KH) wavelengths is used to show the development of quasi-periodic structures in the E-layer. For the model, a background atmosphere near 100 km altitude with a scale height of 12.2 km is subjected to a wind shear profile varying by 100 m/s over a distance of 1.7 km. This neutral speed shear drives the KH instability with a growth time of about 100 seconds. The neutral KH wave is a source of plasma turbulence. The E-layer responds to the KH-Wave structure in the neutral atmosphere as an electrodynamic tracer. The plasma flow leads to small scale plasma field aligned irregularities from a gradient drift, plasma interchange instability (GDI) or a Farley-Buneman, two-stream instability (FBI). These irregularities are detected by radar scatter as quasi-periodic structures. All of these plasma phenomena would not occur without the initiation by neutral atmospheric waves.

The health of irregular and illegal immigrants: analysis of day-hospital admissions in a department of migration medicine.

PubMed

Affronti, Mario; Affronti, Andrea; Pagano, Salvatore; Soresi, Maurizio; Giannitrapani, Lydia; Valenti, Miriam; La Spada, Emanuele; Montalto, Giuseppe

2013-10-01

It is difficult to trace full details of the path which irregular or illegal immigrants follow when seeking assistance in the network of the various hospital departments and health structures. The aim of this work was to analyze the health needs of immigrant people by reviewing the types of treatment given to them in the day-hospital of our Department of Migration Medicine. Our study analyzed day-hospital admissions between 2003 and 2009. The patient charts used for managing day-hospital activity were adopted in 2002 in conformity with the "OSI project". From these it is possible to draw up a scale picture of the distribution of each pathology in the immigrant population. The sample population consisted of 1,758 subjects, representing 7.4% of potential users. More than half came from Africa, followed by Asia, and then Europe. Gastroenterological diseases ranked first, with dyspeptic syndromes most frequently diagnosed. Infections and parasitic diseases ranked second, and the most frequent diagnoses were sexually transmitted diseases. Third were diseases of the genitourinary system. Metabolic disorders ranked fourth, among them, more than half of the cases were of diabetes mellitus, in patients from south-east Asia. Diseases of the circulatory system were sixth, with hypertension the most frequent pathology. Our data confirm a marked persistence of the phenomenon known as the "healthy immigrant effect" in these types of patients, as well as the prominent role played by "social determinants" in conditioning the health of immigrants, particularly in the case of some infectious diseases.

Diagnosis of secondary pulmonary lymphangiectasia in congenital heart disease: a novel role for chest ultrasound and prognostic implications.

PubMed

Lam, Christopher Z; Bhamare, Tanmay Anant; Gazzaz, Tamadhir; Manson, David; Humpl, Tilman; Seed, Mike

2017-10-01

Secondary pulmonary lymphangiectasia is a complication of congenital heart disease that results from chronic pulmonary venous obstruction. We aimed to evaluate the performance of chest ultrasound (US) in diagnosing secondary pulmonary lymphangiectasia and to review the clinical course of children with secondary pulmonary lymphangiectasia. Chest US was performed on 26 children with hypoplastic left heart syndrome, total anomalous pulmonary venous connection or cor triatriatum in a prospective observational study. Thirteen children had pulmonary venous obstruction (62% male; median age: 17 days old, range: 1-430 days old) and 13 children did not have obstruction (62% male; median age: 72 days old, range: 4-333 days old). US features of secondary pulmonary lymphangiectasia were documented and diagnostic performance was determined. Clinical course of patients with secondary pulmonary lymphangiectasia was reviewed. Eleven of 13 (84.6%) patients in the obstructed group had a clinical and/or biopsy diagnosis of secondary pulmonary lymphangiectasia. Statistically significant chest US criteria for diagnosis were presence of irregular lung surface (likelihood ratio [LR] 6.8, 95% confidence interval [CI] 1.9-25.1), subpleural cystic appearing structures (LR 3.6, 95% CI 1.2-10.7), and combination of subpleural cystic appearing structures and surface irregularity together (LR 10.9, 95% CI 1.6-75.0). Seven of 11 (63.6%) patients with secondary pulmonary lymphangiectasia died during follow-up, the majority due to cardiopulmonary failure or complications. Chest US is an accurate and reproducible bedside method for diagnosing secondary pulmonary lymphangiectasia in patients with pulmonary venous obstruction. These patients may have worse prognoses.

Accuracy of ultrasound in antenatal diagnosis of placental attachment disorders.

PubMed

Pilloni, E; Alemanno, M G; Gaglioti, P; Sciarrone, A; Garofalo, A; Biolcati, M; Botta, G; Viora, E; Todros, T

2016-03-01

To evaluate the accuracy of ultrasound in the diagnosis of placenta accreta and its variants, and to assess the impact of prenatal diagnosis in our population. A total of 314 women with placenta previa were enrolled prospectively and underwent transabdominal and transvaginal ultrasound examinations. An ultrasound diagnosis (grayscale and color/power Doppler) of placental attachment disorder (PAD) was based on the detection of at least two of the following ('two-criteria system'): loss/irregularity of the retroplacental clear zone, thinning/interruption of the uterine serosa-bladder wall interface, turbulent placental lacunae with high velocity flow, myometrial thickness < 1 mm, increased vascularity of the uterine serosa-bladder wall interface, loss of vascular arch parallel to the basal plate and/or irregular intraplacental vascularization. Definitive diagnosis was made at delivery by Cesarean section. Maternal outcome in cases diagnosed antenatally was compared with that in cases diagnosed at delivery. There were 37/314 cases of PAD (29 anterior and eight posterior). The two-criteria system identified 30 cases of placenta accreta, providing a sensitivity of 81.1% and specificity of 98.9%. When anterior and posterior placentae were considered separately, the detection rates of PAD were 89.7 and 50.0%, respectIvely. Maternal outcome was better in women with prenatal diagnosis of PAD, as seen by less blood loss and shorter hospitalization. Our data confirmed that grayscale and color Doppler ultrasound have good performance in the diagnosis of PAD and that prenatal diagnosis improves maternal outcome. Copyright © 2015 ISUOG. Published by John Wiley & Sons Ltd. Copyright © 2015 ISUOG. Published by John Wiley & Sons Ltd.

Comparison of efficacy of metformin and oral contraceptive combination of ethinyl estradiol and drospirenone in polycystic ovary syndrome.

PubMed

Suvarna, Yashasvi; Maity, Nivedita; Kalra, Pramila; Shivamurthy, M C

2016-01-01

The 2013 Endocrine Society guidelines state that hormonal contraceptives should be used for treating both menstrual irregularity and hirsutism in patients with polycystic ovary syndrome (PCOS). Metformin should be reserved for the treatment of women presenting with only menstrual irregularity because it has limited benefits in treating hyperandrogenism associated with PCOS. A high prevalence of insulin resistance is noted among the South Asians, and these guidelines may not hold good for this population. Thus, this study was conducted to investigate and compare the effects of metformin and an oral contraceptive containing drospirenone on menstrual pattern, body mass index, serum testosterone levels, and dehydroepiandrosterone sulfate (DHEAS) levels at baseline to 6 months of therapy in the treatment groups. This was a prospective observational study that was conducted over a year in patients visiting the Endocrinology outpatient department at a tertiary care center in a south Indian city. Forty-six subjects diagnosed with PCOS as per the Rotterdam criteria were included. They received either metformin twice daily or an oral contraceptive containing drospirenone once daily as a monthly regimen for 6 months. Metformin regularized menstrual cycles in 72% of patients who were followed up at 6 months. No significant difference was observed between the two treatment groups with respect to decreasing the body mass index, serum testosterone levels, and DHEAS levels (p=0.40, p=0.65, and p=0.22, respectively). Metformin is effective in regularizing menstrual cycles, decreasing body mass index, and treating hyperandrogenism in Indian women diagnosed with PCOS.

Spatial structure of plasma density perturbations, induced in the ionosphere modified by powerful HF radio waves: Review of experimental results

NASA Astrophysics Data System (ADS)

Frolov, Vladimir

2015-06-01

In the review, the results of experimental studies of spatial structure of small-, middle-, and large scale plasma density perturbations induced in the ionosphere by its pumping by powerful HF O-mode (ordinary) radio waves, are analyzed. It is shown that the region with induced plasma density perturbations occupied all ionosphere body from its E-region up to the topside ionosphere in the height and it has the horizontal length of about of 300-500 km. Peculiarities of generation of artificial ionosphere irregularities of different scale-lengths in the magnetic zenith region are stated. Experimental results obtained under conditions of ionosphere periodical pumping when the generation of travel ionosphere disturbances is revealed are also discussed.

Lightweight Concrete Produced Using a Two-Stage Casting Process.

PubMed

Yoon, Jin Young; Kim, Jae Hong; Hwang, Yoon Yi; Shin, Dong Kyu

2015-03-25

The type of lightweight aggregate and its volume fraction in a mix determine the density of lightweight concrete. Minimizing the density obviously requires a higher volume fraction, but this usually causes aggregates segregation in a conventional mixing process. This paper proposes a two-stage casting process to produce a lightweight concrete. This process involves placing lightweight aggregates in a frame and then filling in the remaining interstitial voids with cementitious grout. The casting process results in the lowest density of lightweight concrete, which consequently has low compressive strength. The irregularly shaped aggregates compensate for the weak point in terms of strength while the round-shape aggregates provide a strength of 20 MPa. Therefore, the proposed casting process can be applied for manufacturing non-structural elements and structural composites requiring a very low density and a strength of at most 20 MPa.

[Laboratory analysis of the first case of imported oval malaria in Rizhao City].

PubMed

Chao, Li; Ying, Zhang; Ting, Xiao

2016-01-25

To diagnose the first imported case of Plasmodium ovale infection by laboratory detection. The epidemiological data and blood samples of the case were collected, and the samples were detected by the microscopic examination, rapid diagnostic test (RDT) and nested PCR. The patient was a construction worker backing from Congo, Africa. He experienced the symptoms of irregular fever and weakness one month after returning in Lingyang Town, Junxian County. The results of RDT only suggested no- Plasmodium falciparum infection. Under the microscope, it was seen that the infected RBC were obviously disfigured and in irregular shape, the ring forms were thick and big, and also thick granulas in big trophozoite stage and schizont stage were found. The results of PCR showed that the size of amplified product was about 800 bp, which was conformed to that of P. ovale . Though microscopic examination is the golden standard for malaria diagnosis, as P. ovale is difficult to be identified under microscope, the microscopic method combined with PCR test can be used for definite diagnosis.

[A case of respiratory dyskinesia due to clebopride malate].

PubMed

Kawasaki, H; Yamamoto, M; Okayasu, H; Wakayama, Y

1991-08-01

Clebopride malate is therapeutically used for the treatment of peptic ulcer. This drug has potent antidopaminergic activity that causes acute dystonic reaction, parkinsonism and tardive dyskinesia as adverse effects. Here, we have reported an 86-year-old man who developed abnormal involuntary movement of respiratory muscles and lower limb muscles after this drug had been given for four months. This involuntary movement appeared spontaneously at resting state and disappeared during sleep. Surface EMG demonstrated a synchronous grouping discharge in m. orbicularis oris, m. sternocleidomastoideus and m. interstales which synchronized with diaphragmatic movement on cinefluorography. Involuntary movement of the lower limbs was synchronous bilaterally and had little relationship with diaphragmatic movement. This involuntary movement was irregular not only in rhythm but also in duration. According to this irregular nature, we diagnosed this involuntary movement as respiratory dyskinesia with limb dyskinesia that belongs to tardive dyskinesia. After cessation of clebopride malate limb dyskinesia disappeared rapidly and respiratory dyskinesia markedly decreased. We emphasize that respiratory dyskinesia should be differentiated from psychogenic hyperventilation as easily misdiagnosed on initial examination.

Anterior Segment Ischemia after Strabismus Surgery

PubMed Central

Göçmen, Emine Seyhan; Atalay, Yonca; Evren Kemer, Özlem; Sarıkatipoğlu, Hikmet Yavuz

2017-01-01

A 46-year-old male patient was referred to our clinic with complaints of diplopia and esotropia in his right eye that developed after a car accident. The patient had right esotropia in primary position and abduction of the right eye was totally limited. Primary deviation was over 40 prism diopters at near and distance. The patient was diagnosed with sixth nerve palsy and 18 months after trauma, he underwent right medial rectus muscle recession. Ten months after the first operation, full-thickness tendon transposition of the superior and inferior rectus muscles (with Foster suture) was performed. On the first postoperative day, slit-lamp examination revealed corneal edema, 3+ cells in the anterior chamber and an irregular pupil. According to these findings, the diagnosis was anterior segment ischemia. Treatment with 0.1/5 mL topical dexamethasone drops (16 times/day), cyclopentolate hydrochloride drops (3 times/day) and 20 mg oral fluocortolone (3 times/day) was initiated. After 1 week of treatment, corneal edema regressed and the anterior chamber was clean. Topical and systemic steroid treatment was gradually discontinued. At postoperative 1 month, the patient was orthophoric and there were no pathologic symptoms besides the irregular pupil. Anterior segment ischemia is one of the most serious complications of strabismus surgery. Despite the fact that in most cases the only remaining sequel is an irregular pupil, serious circulation deficits could lead to phthisis bulbi. Clinical properties of anterior segment ischemia should be well recognized and in especially risky cases, preventative measures should be taken. PMID:28182149

Early childhood sleep and eating problems as predictors of adolescent and adult mood and anxiety disorders.

PubMed

Ong, Say How; Wickramaratne, Priya; Tang, Min; Weissman, Myrna M

2006-11-01

Recent studies have suggested that eating and sleep problems during early childhood may pose as risk factors for mood and anxiety disorders in later life. We aim to study the associations between early childhood sleep and eating problems, specifically high motor activity during sleep and irregularities in sleep/eating schedules, and lifetime history of mood and anxiety disorders. We followed up 164 offspring, who were at high and low risk for major depression by virtue of their parental history (at least one parent had Major Depressive Disorder). Target sleep and eating problems were measured using Dimensions of Temperament Survey (DOTS). The offspring were blindly assessed at 3 times over 20 years using a structured diagnostic interview. Irregularities in sleeping and eating schedules in childhood (low rhythmicity) was associated with adolescent-onset major depression and anxiety disorder, as well as childhood-onset anxiety disorder. High motor activity level during sleep was associated with both childhood-onset and adolescent-onset dysthymic disorder. Neither childhood sleep nor eating irregularities were associated with adult onset psychopathology. Retrospective reports of childhood sleep and eating patterns were derived from parent-reports. Reported problems may overlap with clinical diagnoses. Clinicians should be alerted to parental reports of children's sleep and eating problems suggesting low rhythmicity, as well as high motor activity levels during sleep. These early behaviors may be predictive of subsequent mood and anxiety disorders in childhood and adolescence.

Adolescent girls, the menstrual cycle, and bone health.

PubMed

Adams Hillard, Paula J; Nelson, Lawrence M

2003-05-01

In adolescent girls, amenorrhea is sometimes viewed as a variant of normal; in fact, however, during the first gynecologic year, the 95th percentile for cycle length is 90 days. Although early menstrual cycles are frequently anovulatory and may be somewhat irregular, girls with menses coming less frequently than every 90 days may have significant pathology associated with hypoestrogenism. Hypoestrogenism is a known risk factor for the development of osteoporosis. Causes of oligomenorrhea and amenorrhea include the relatively common conditions of hyperandrogenism, eating disorders, and exercise-induced amenorrhea, as well as uncommon conditions such as pituitary tumor, gonadal dysgenesis, and premature ovarian failure. Even functional hypothalamic oligomenorrhea has been linked to reduced bone density. Attention to menstrual irregularity and the earlier diagnosis of conditions causing it may lead to interventions that will benefit life-long bone health.

The height of electron content changes in the ionosphere from ATS 6 beacon data

NASA Technical Reports Server (NTRS)

Davies, K.; Heron, M. L.

1984-01-01

A technique is described which uses relative changes in Faraday rotation and modulation phase of satellite radio signals to determine the median height of the enhancement (or depletion) in the electron density of the ionosphere. During the post sunrise formation of the F layer the incremental layers have a median height of around 210 km (+ or - 40) and in the afternoon the decremental median is above the peak at 340 km (+ or - 40) on a winter day. A winter nighttime enhancement just after midnight appears as a thick layer extending upwards from the peak, with a median height at about 730 km. The method applies to large scale irregularities but not to small, dense, scintillation-causing irregularities for which Faraday and modulation phases do not represent the total electron content.

ARA type protograph codes

NASA Technical Reports Server (NTRS)

Divsalar, Dariush (Inventor); Abbasfar, Aliazam (Inventor); Jones, Christopher R. (Inventor); Dolinar, Samuel J. (Inventor); Thorpe, Jeremy C. (Inventor); Andrews, Kenneth S. (Inventor); Yao, Kung (Inventor)

2008-01-01

An apparatus and method for encoding low-density parity check codes. Together with a repeater, an interleaver and an accumulator, the apparatus comprises a precoder, thus forming accumulate-repeat-accumulate (ARA codes). Protographs representing various types of ARA codes, including AR3A, AR4A and ARJA codes, are described. High performance is obtained when compared to the performance of current repeat-accumulate (RA) or irregular-repeat-accumulate (IRA) codes.

Method of casting aerogels

DOEpatents

Poco, John F.

1993-01-01

The invention describes a method for making monolithic castings of transparent silica aerogel with densities in the range from 0.001 g/cm.sup.3 to 0.6 g/cm.sup.3. Various shapes of aerogels are cast in flexible polymer molds which facilitate removal and eliminate irregular surfaces. Mold dimensions are preselected to account for shrinkage of alcogel which occurs during the drying step of supercritical extraction of solvent.

Rhabdomyolysis After Cosmetic Laser-Assisted Liposuction.

PubMed

Shin, Jin-yong; Chang, Hak

2015-08-01

A 34-year-old-female patient visited our emergency room for symptoms of disturbance of urination and shortness of breath. She was diagnosed with rhabdomyolysis with acute kidney injury after laser-assisted liposuction and required hemodialysis. Although laser-assisted liposuction is a well-used procedure, it can cause local complications, such as burns and skin irregularities, as well as systemic complications, such as infection, fever, and emboli. However, laser-assisted, liposuction-induced rhabdomyolysis has not been reported. Repetitive exercises, trauma, and crush injury are the major causes of rhabdomyolysis. In this study, a unique case of rhabdomyolysis that developed after laser-assisted liposuction is reported.

Chondromyxoid fibroma of the mastoid facial nerve canal mimicking a facial nerve schwannoma.

PubMed

Thompson, Andrew L; Bharatha, Aditya; Aviv, Richard I; Nedzelski, Julian; Chen, Joseph; Bilbao, Juan M; Wong, John; Saad, Reda; Symons, Sean P

2009-07-01

Chondromyxoid fibroma of the skull base is a rare entity. Involvement of the temporal bone is particularly rare. We present an unusual case of progressive facial nerve paralysis with imaging and clinical findings most suggestive of a facial nerve schwannoma. The lesion was tubular in appearance, expanded the mastoid facial nerve canal, protruded out of the stylomastoid foramen, and enhanced homogeneously. The only unusual imaging feature was minor calcification within the tumor. Surgery revealed an irregular, cystic lesion. Pathology diagnosed a chondromyxoid fibroma involving the mastoid portion of the facial nerve canal, destroying the facial nerve.

A narrow QRS tachycardia and cannon A waves: What is the mechanism?

PubMed

Ali, Hussam; Epicoco, Gianluca; De Ambroggi, Guido; Lupo, Pierpaolo; Foresti, Sara; Cappato, Riccardo

2017-07-01

Regular narrow QRS tachycardia, particularly if well-tolerated, is usually considered a "benign" arrhythmia of a supraventricular origin. This case concerns an 82-year-old male with ischemic heart disease who presented with recurrent episodes of a narrow QRS tachycardia that was initially diagnosed and treated as atrial tachyarrhythmia. However, careful physical examination and ECG analysis established the correct diagnosis, and the patient was managed appropriately. Remarkably, the observation of irregular cannon A waves, and Lewis lead recording, confirmed atrioventricular dissociation during tachycardia and indicated its underlying mechanism. © 2016 Wiley Periodicals, Inc.

Prevalent Signs and Symptoms in Patients with Skin Cancer and Nursing Diagnoses.

PubMed

Lisboa, Isabel Neves Duarte; Azevedo Macena, Monica Suela de; Conceicao Dias, Maria Isabel Fernandes da; Almeida Medeiros, Ana Beatriz de; Lima, Cyndi Fernandes de; Carvalho Lira, Ana Luisa Brandao de

2016-01-01

Skin cancer has a remarkable importance given the high incidence in the population. In Brazil, it is estimated that there were 98,420 new cases of nonmelanoma skin cancer among men and 83,710 new cases among women in 2014. To verify signs and symptoms present in patients with skin neoplasms according to the literature and relate them to the nursing diagnoses of NANDA International. Integrative literature review carried out from March to May 2015 in the databases: Cumulative Index to Nursing and Allied Health Literature, SCOPUS, National Library of Medicine and Nattional Institutes of Health, Latin American and Caribbean Sciences of Health and Web of Science. The descriptors used were: 'Signs and Symptoms' and 'Skin Neoplasms'. Sixteen articles were identified as the final sample. After review, the signs and symptoms of skin cancer identified in the literature were related to the defining characteristics present in NANDA International, with the aim to trace possible nursing diagnoses. The most prevalent signs and symptoms were: asymmetric and well circumscribed nodules with irregular borders; speckles with modified color aspect; ulcerations; blisters; pain; itching; and bleeding. The principal nursing diagnoses outlined were: risk for impaired skin integrity; impaired skin integrity; acute pain; risk of shock; and impaired comfort. The identification of signs and symptoms present in patients with skin cancer and the relationships of these with the nursing diagnoses of NANDA International provide a basis for qualified and systematized nursing care to this clientele.

The influence of artificial electron heating on plasma irregularities in the lower ionosphere

NASA Astrophysics Data System (ADS)

Kyzyurov, Yurij; Chernogor, Leonid F.

It is known small-scale ionospheric irregularities below the homopause level are generated by the neutral air turbulence. Usually an approximation of isothermality Te = Ti = Tn is valid for the lower ionosphere, especially, at middle latitudes. However, the approximation may be broken due to electron heating by powerful radio waves. In the report we consider theoretically reaction of ionospheric irregularities created by the neutral turbulence on the increasing of electron temperature Te due to the radio wave action. For this aim, expressions for the irregularity spectrum, the mean-square level of the plasma density fluctuations, and the radar backscatter cross-section per unit volume have been obtained. Using the expressions we have calculated the spectral form, the rms fluctuation level, and the cross-section σ for the case of the mid-latitude ionosphere at an altitude near 100 km when the ratio of the electron to ion temperature Te /Ti increased from 1 to 10. The spectrum has corresponded to the inertial range of turbulence, the rms level has been estimated for irregularity length-scales smaller than 500 m, and σ has been evaluated for the diagnostic radar frequencies from 5 to 50 MHz and the vertical direction of antenna beam. It was shown that an increase in Te produces a decrease in both the fluctuation level and the backscatter cross-section. In our calculations this level reduced from 6.2 to 4.8 %; the cross-section σ from 1.28×10-8 to 9.06×10-9 m-1 at 5 MHz and from 1.25×10-11 to 8.93×10-12 m-1 at 50 MHz. The rise in Te has also resulted in an increase in the spectral slope (for the approximation of spectrum by a power law k -p , the index p took values from 1.62 to 2.34). These changes are explained by a decrease in the cut-off wavenumber in the irregularity spectrum resulted from an increase in the ambipolar diffusivity due to the rise in Te .

Accuracy of methods for detecting an irregular pulse and suspected atrial fibrillation: A systematic review and meta-analysis.

PubMed

Taggar, Jaspal S; Coleman, Tim; Lewis, Sarah; Heneghan, Carl; Jones, Matthew

2016-08-01

Pulse palpation has been recommended as the first step of screening to detect atrial fibrillation. We aimed to determine and compare the accuracy of different methods for detecting pulse irregularities caused by atrial fibrillation. We systematically searched MEDLINE, EMBASE, CINAHL and LILACS until 16 March 2015. Two reviewers identified eligible studies, extracted data and appraised quality using the QUADAS-2 instrument. Meta-analysis, using the bivariate hierarchical random effects method, determined average operating points for sensitivities, specificities, positive and negative likelihood ratios (PLR, NLR); we constructed summary receiver operating characteristic plots. Twenty-one studies investigated 39 interventions (n = 15,129 pulse assessments) for detecting atrial fibrillation. Compared to 12-lead electrocardiography (ECG) diagnosed atrial fibrillation, blood pressure monitors (BPMs; seven interventions) and non-12-lead ECGs (20 interventions) had the greatest accuracy for detecting pulse irregularities attributable to atrial fibrillation (BPM: sensitivity 0.98 (95% confidence interval (CI) 0.92-1.00), specificity 0.92 (95% CI 0.88-0.95), PLR 12.1 (95% CI 8.2-17.8) and NLR 0.02 (95% CI 0.00-0.09); non-12-lead ECG: sensitivity 0.91 (95% CI 0.86-0.94), specificity 0.95 (95% CI 0.92-0.97), PLR 20.1 (95% CI 12-33.7), NLR 0.09 (95% CI 0.06-0.14)). There were similar findings for smartphone applications (six interventions) although these studies were small in size. The sensitivity and specificity of pulse palpation (six interventions) were 0.92 (95% CI 0.85-0.96) and 0.82 (95% CI 0.76-0.88), respectively (PLR 5.2 (95% CI 3.8-7.2), NLR 0.1 (95% CI 0.05-0.18)). BPMs and non-12-lead ECG were most accurate for detecting pulse irregularities caused by atrial fibrillation; other technologies may therefore be pragmatic alternatives to pulse palpation for the first step of atrial fibrillation screening. © The European Society of Cardiology 2015.

A comparative study of Cyclofem and depot medroxyprogesterone acetate (DMPA) effects on endometrial vasculature.

PubMed

Simbar, Masoumeh; Tehrani, Fahimeh Ramezani; Hashemi, Zeinab; Zham, Hananeh; Fraser, Ian S

2007-10-01

The most common reason for discontinuation of long-acting progestogen-only contraceptives is irregular bleeding following local endometrial vascular changes. To reduce unpredictable bleeding episodes among depot medroxyprogesterone acetate (DMPA) users, the combined injectable contraceptive, Cyclofem, was offered as an alternative. However, there is a gap in our knowledge about the effects of Cyclofem on the endometrial vasculature and patterns of bleeding. This study aimed to compare the effects of Cyclofem and DMPA on endometrial vascular density, endometrial histology and pattern of bleeding. Sixty-eight healthy women with regular menstrual bleeding and seeking injectable long-acting contraceptives were recruited. Two endometrial samples (before and 3 to 6 months after initial exposure to DMPA or Cyclofem) were collected from each participant. The samples were stained using an immunohistochemical method and anti-CD34 to visualise the endometrial vasculature. Endometrial vascular density was assessed using standard techniques. Sixty-eight women were randomly assigned to Cyclofem (38 women) or DMPA (30 women). Endometrial vascular density was 149.3 +/- 6.7 (mean +/- SD)/mm(2) before injection. This significantly decreased to 132.4 +/- 12.2 after DMPA use, and from 151.9 +/- 5.8 to 131.8 +/- 12.8 vessels/mm(2) following Cyclofem use (paired t-test, p <0.05). However, there was no significant difference between endometrial vascular density during treatment with Cyclofem or DMPA. Total bleeding days in the first and second 3-month time intervals were 28 +/- 23 and 18 +/- 12 days in DMPA users and 22 +/- 14 and 16 +/- 9 days in Cyclofem users, respectively, Spotting was the most common type of bleeding experienced, and atrophic endometrium was the most common histological pattern observed in both groups. This study demonstrated that both Cyclofem and DMPA use are associated with decreased endometrial vascular density and atrophic endometrium, in addition to irregular bleeding, mainly spotting. There was no significant difference in bleeding patterns or endometrial findings observed for these two injectable contraceptives in Iranian women.

The size, shape, density, and albedo of Ceres from its occultation of BD+8 deg 471

NASA Technical Reports Server (NTRS)

Millis, R. L.; Wasserman, L. H.; Franz, O. G.; Nye, R. A.; Oliver, R. C.; Kreidl, T. J.; Jones, S. E.; Hubbard, W.; Lebofsky, L.; Goff, R.

1986-01-01

The occultation of BD+8 degrees 471 by Ceres on 13 November 1984 was observed photoelectrically at 13 sites in Mexico, Florida, and the Caribbean. These observations indicate that Ceres is an oblate spheroid having an equatorial radius of 479.6 + or - 2.4 km and a polar radius of 453.4 + or - 4.5 km. The mean density of this minor planet is 2.7 gm/cubic cm + or - 5%, and its visual geometric albedo is 0.070. While the surface appears globally to be in hydrostatic equilibrium, firm evidence of real limb irregularities is seen in the data.

I(CO)/N(H2) conversions and molecular gas abundances in spiral and irregular galaxies

NASA Technical Reports Server (NTRS)

Maloney, Philip; Black, John H.

1988-01-01

Observations of emission in the J = 1-0 rotational transition of interstellar CO are used to obtain column densities and masses of hydrogen. By taking into account the effects of variations in molecular cloud parameters on conversion factors between integrated CO intensity and molecular hydrogen column density, it is shown that conversion factors are very sensitive to the kinetic temperature of the emitting gas. Results indicate that the gas temperatures in systems with high star formation rates can be quite high, and it is suggested that use of a standard conversion factor will lead to systematic overestimation of the amount of molecular gas.

Lightweight Concrete Produced Using a Two-Stage Casting Process

PubMed Central

Yoon, Jin Young; Kim, Jae Hong; Hwang, Yoon Yi; Shin, Dong Kyu

2015-01-01

The type of lightweight aggregate and its volume fraction in a mix determine the density of lightweight concrete. Minimizing the density obviously requires a higher volume fraction, but this usually causes aggregates segregation in a conventional mixing process. This paper proposes a two-stage casting process to produce a lightweight concrete. This process involves placing lightweight aggregates in a frame and then filling in the remaining interstitial voids with cementitious grout. The casting process results in the lowest density of lightweight concrete, which consequently has low compressive strength. The irregularly shaped aggregates compensate for the weak point in terms of strength while the round-shape aggregates provide a strength of 20 MPa. Therefore, the proposed casting process can be applied for manufacturing non-structural elements and structural composites requiring a very low density and a strength of at most 20 MPa. PMID:28788007

The structure of the magnetosphere as deduced from magnetospherically reflected whistlers

NASA Technical Reports Server (NTRS)

Edgar, B. C.

1972-01-01

Very low frequency (VLF) electromagnetic wave phenomenon called the magnetospherically reflected (MR) whistler was investigated. VLF (0.3 to 12.5 kHz) data obtained from the Orbiting Geophysical Observatories 1 and 3 from October 1964 to December 1966 were used. MR whistlers are produced by the dispersive propagation of energy from atmospheric lightning through the magnetosphere to the satellite along ray paths which undergo one or more reflections due to the presence of ions. The gross features of MR whistler frequency-time spectrograms are explained in terms of propagation through a magnetosphere composed of thermal ions and electrons and having small density gradients across L-shells. Irregularities observed in MR spectra were interpreted in terms of propagation through field-aligned density structures. Trough and enhancement density structures were found to produce unique and easily recognizable signatures in MR spectra. Sharp cross-field density dropoff produces extra traces in MR spectrograms.

Gynecologic disorders diagnosed during deployment to Southwest/Central Asia, active component females, U.S. Armed Forces, 2008-2013.

PubMed

2014-08-01

Service women in the U.S. Armed Forces face unique challenges that may lead to or exacerbate gynecologic disorders - particularly during deployment. This report documented that approximately one in 10 military women who served in Southwest/Central Asia were diagnosed with a gynecologic disorder at least once during deployment. In addition, gynecologic disorders accounted for approximately one of every 20 medical evacuations of female service members from the war zone. A majority of clinically significant gynecologic disorder cases were attributable to irregular menstruation/bleeding or unspecified inflammation or pain of the female genital organs. Incidence rates of gynecologic disorder diagnoses were higher among black, non-Hispanic service women, among younger women, and among those in the Army and in motor transport and communications/intelligence occupations. Approximately 50% of gynecologic disorder cases had received gynecologic care within 6 months prior to deployment and nearly 90% had received care within 2 years of deployment. Despite pre-deployment care, it is apparent from this report that service women need continuous access to gynecologic care during deployment, particularly if conditions during deployment lead to and exacerbate gynecologic disorders.

Syntactic methods of shape feature description and its application in analysis of medical images

NASA Astrophysics Data System (ADS)

Ogiela, Marek R.; Tadeusiewicz, Ryszard

2000-02-01

The paper presents specialist algorithms of morphologic analysis of shapes of selected organs of abdominal cavity proposed in order to diagnose disease symptoms occurring in the main pancreatic ducts and upper segments of ureters. Analysis of the correct morphology of these structures has been conducted with the use of syntactic methods of pattern recognition. Its main objective is computer-aided support to early diagnosis of neoplastic lesions and pancreatitis based on images taken in the course of examination with the endoscopic retrograde cholangiopancreatography (ERCP) method and a diagnosis of morphological lesions in ureter based on kidney radiogram analysis. In the analysis of ERCP images, the main objective is to recognize morphological lesions in pancreas ducts characteristic for carcinoma and chronic pancreatitis. In the case of kidney radiogram analysis the aim is to diagnose local irregularity of ureter lumen. Diagnosing the above mentioned lesion has been conducted with the use of syntactic methods of pattern recognition, in particular the languages of shape features description and context-free attributed grammars. These methods allow to recognize and describe in a very efficient way the aforementioned lesions on images obtained as a result of initial image processing into diagrams of widths of the examined structures.

Split sample comparison of a liquid-based method and conventional smears in thyroid fine needle aspiration.

PubMed

Jung, Chan-Kwon; Lee, Ahwon; Jung, Eun-Sun; Choi, Yeong-Jin; Jung, So-Lyung; Lee, Kyo-Young

2008-01-01

To compare the efficacy of the SurePath (SP) vs. conventional smears (CS) in fine needle aspiration (FNA) of thyroid gland lesions. A total of 193 FNA cases with thyroid nodules were studied. Samples from ultrasound-guided FNA were split to prepare CS and SP slides. The diagnostic categories of unsatisfactory, benign, atypical and malignant were compared. Galectin-3 immunostaining was performed on SP slides. Some differences were found between the cytomorphology of CS and SP. SP slides showed more increased cellularity and more clustered tissue fragments. On SP slides, nuclear detail and nucleoli were more easily detected and nuclear irregularity was very useful for the diagnosis of papillary carcinoma. SP showed a trend toward a lower proportion of atypical category. The overall sensitivity of FNA in diagnosing thyroid neoplasm was 90.9% for CS and 93.9% for SP. Most lesions (73%) diagnosed as papillary carcinoma after surgery showed positive staining of galectin-3. The SP method showed easy evaluation of cytomorphologic features and consistent specimen quality and appeared to be more useful in diagnosing the suspicious cases. Moreover, it offered the possibility of adjunctive immunocytochemistry on the same sample.

Shape, Density, and Geology of the Nucleus of Comet 103P/Hartley 2

NASA Technical Reports Server (NTRS)

Thomas, P.C.; A'hearn, Michael F.; Veverka, Joseph; Belton, Michael J. S.; Kissel, Jochen; Belton, Michael J. S.; Klaasen, Kenneth P.; McFadden, Lucy A.; Melosh, H. Jay; Schultz, Peter H.;

The surface morphology of crystals melting under solutions of different densities

NASA Technical Reports Server (NTRS)

Fang, Dacheng; Hellawell, A.

1988-01-01

Examples of solids melting beneath liquids are described for cases where the bulk liquid volume is stabilized against convection by a positive vertical temperature gradient, either with, or without local density inversion at the melting interface. The examples include ice melting beneath brine or methanol solutions and tin or lead melting under molten Sn-20 wt pct Pb or Pb-20 wt pct Sn, respectively. Without density inversion the melting is slow, purely diffusion controlled and the interfaces are smooth; with convection assisted melting the rate increases by some two orders of magnitude and the interfaces develop a rough profile - in the case of ice both irregular and quasi-steady state features are observed. The observations are discussed in terms of prevailing temperature and concentration gradients.

Understanding the Unique Equatorial Density Irregularities

DTIC Science & Technology

2015-04-01

3 Bahir Dar, 79 ETHIOPIA EOARD GRANT #FA8655-13-1-3052 Report Date: April 2015 Final Report from 15 June 2013 to 30 March 2015 Air Force...ADDRESS(ES) Bahir Dar University Peda Straight, Region 3 Bahir Dar, 79 ETHIOPIA 8. PERFORMING ORGANIZATION REPORT NUMBER N/A 9. SPONSORING/MONITORING...satellite signal receivers and others in collaboration with institutions outside Ethiopia . This effort provided some support for the installation of the

Method of casting aerogels

DOEpatents

Poco, J.F.

1993-09-07

The invention describes a method for making monolithic castings of transparent silica aerogel with densities in the range from 0.001 g/cm[sup 3] to 0.6 g/cm[sup 3]. Various shapes of aerogels are cast in flexible polymer molds which facilitate removal and eliminate irregular surfaces. Mold dimensions are preselected to account for shrinkage of aerogel which occurs during the drying step of supercritical extraction of solvent. 2 figures.

Serum lipid levels and steroidal hormones in women runners with irregular menses.

PubMed

Thompson, D L; Snead, D B; Seip, R L; Weltman, J Y; Rogol, A D; Weltman, A

1997-02-01

This study compared the lipid profile of women runners with menstrual cycle irregularities with their normally menstruating counterparts. Relationships among selected steroid hormones and serum lipid levels in 10 eumenorrheic (EU) and 8 oligo-/amenorrheic (O/A) women runners and 6 eumenorrheic controls (CON) were examined. Serum 17 beta-estradiol (E2), progesterone (Prog), and dehydroepiandrosterone-sulfate (DHEAS) concentrations were determined in daily blood samples for 21 days, and integrated concentrations were calculated. Fasting blood samples were analyzed for total cholesterol (TC), low-density lipoprotein cholesterol (LDL-C), high-density lipoprotein cholesterol (HDL-C), HDL2, HDL3, triglycerides (Trig), and apolipoproteins A-1, A-II, and B. The O/A group had significantly lower E2 and Prog than EU or CON groups. Women in the CON group had lower HDL-C and HDL3 than the runners. With all women grouped together, E2 was not significantly correlated with any measured blood lipid parameters. On the other hand, DHEAS was significantly correlated with HDL-C, HDL2, and apolipoprotein A-I. These data demonstrate that women runners, regardless of menstrual cycle status, exhibit higher HDL-C concentrations than CON and supports previous research reporting a positive association between DHEAS and HDL-C.

Evaluation of chondromalacia of the patellofemoral compartment with axial magnetic resonance imaging.

PubMed

Brown, T R; Quinn, S F

1993-01-01

Axial magnetic resonance (MR) imaging of the patellofemoral compartment was performed in 75 patients with arthroscopic correlation. Proton density and T2(2500/20/80) weighted images were obtained in all patients. Chondromalacia in stages I and II could not be reliably identified with MR imaging. For the evaluation of stage III and IV chondromalacia, the accuracy of MR was 89%. Focal or diffuse areas of increased or decreased signal alterations of the hyaline cartilage without a contour deformity or cartilaginous thinning do not correlate reliably with arthroscopic staging of chondromalacia. A normal signal intensity is no assurance that softening of the cartilage is not present. The most reliable indicators of chondromalacia are focal contour irregularities of the hyaline cartilage and/or thinning of the hyaline cartilage associated with high signal intensity changes within frank defects or contour irregularities with T2-weighted images. The poor MR-arthroscopic correlation in earlier stages of chondromalacia may be due in part to the subjective basis of the arthroscopic diagnosis. In conclusion, stage I and II chondromalacia of the patellofemoral compartment cannot be reliably evaluated with MR imaging. Stage III and IV chondromalacia is reliably evaluated with MR using the combination of proton density and T2-weighted images.

Light scattering by low-density agglomerates of micron-sized grains with the PROGRA2 experiment

NASA Astrophysics Data System (ADS)

Hadamcik, E.; Renard, J.-B.; Lasue, J.; Levasseur-Regourd, A. C.; Blum, J.; Schraepler, R.

2007-07-01

This work was carried out with the PROGRA2 experiment, specifically developed to measure the angular dependence of the polarization of light scattered by dust particles. The samples are small agglomerates of micron-sized grains and huge, low number density agglomerates of the same grains. The constituent grains (spherical or irregularly shaped) are made of different non-absorbing and absorbing materials. The small agglomerates, in a size range of a few microns, are lifted by an air draught. The huge centimeter-sized agglomerates, produced by random ballistic deposition of the grains, are deposited on a flat surface. The phase curves obtained for monodisperse, micron-sized spheres in agglomerates are obviously not comparable to the ‘smooth’ phase curves obtained by remote observations of cometary dust or asteroidal regoliths but they are used for comparison with numerical calculations to a better understanding of the light scattering processes. The phase curves obtained for irregular grains in agglomerates are similar to those obtained by remote observations, with a negative branch at phase angles smaller than 20° and a maximum polarization decreasing with increasing albedo. These results, coupled with remote observations in the solar system, should provide a better understanding of the physical properties of solid particles and their variation in cometary comae and asteroidal regoliths.

Menses resumption after cancer treatment-induced amenorrhea occurs early or not at all.

PubMed

Jacobson, Melanie H; Mertens, Ann C; Spencer, Jessica B; Manatunga, Amita K; Howards, Penelope P

2016-03-01

To identify factors associated with cancer treatment-induced amenorrhea and time to return of menses. Population-based cohort study. Not applicable. Female cancer survivors who were diagnosed with cancer between the ages of 20 and 35 and were at least 2 years postdiagnosis at the time of recruitment (median = 7 years; interquartile range, 5-11). None. Amenorrhea (≥6 months without menses) and resumption of menses. After excluding women with hysterectomies before cancer diagnosis, 1,043 women were eligible for analysis. Amenorrhea occurred in 31.6% of women. Among women treated with chemotherapy (n = 596), older age at diagnosis (30-35 vs. 20-24 years: adjusted odds ratio [aOR] = 2.37; 95% confidence interval [CI], 1.30, 4.30) and nulligravidity (vs. gravid: aOR = 1.50; 95% CI, 1.02, 2.21) were risk factors for amenorrhea. Among amenorrheic women, menses resumed in most (70.0%), and resumption occurred within 2 years of treatment for 90.0% of women. Survivors of breast cancer were more likely to resume menses at times greater than 1 year compared with lymphoma and pelvic-area cancers. Women diagnosed at older ages, those exposed to chemotherapy, and those exposed to any radiation experienced longer times to return of menses. Women who were older at diagnosis were more likely to have irregular cycles when menses returned. Treatment-induced amenorrhea is common in cancer survivors, although most women resume menses within 2 years. However, once resumed, older women are more likely to have irregular cycles. Age at diagnosis and pregnancy history affect the risk of amenorrhea. Copyright © 2016 American Society for Reproductive Medicine. Published by Elsevier Inc. All rights reserved.

Menses resumption after cancer treatment-induced amenorrhea occurs early or not at all

PubMed Central

Jacobson, Melanie H.; Mertens, Ann C.; Spencer, Jessica B.; Manatunga, Amita K.; Howards, Penelope P.

2015-01-01

Objective To identify factors associated with cancer treatment-induced amenorrhea and time to return of menses. Design Population-based cohort study Setting Georgia Patients Female cancer survivors who were diagnosed with cancer between the ages of 20–35 and were at least 2 years post-diagnosis at the time of recruitment (median=7 years, interquartile range= 5–11). Intervention(s) None Main Outcome Measure(s) Amenorrhea (≥ 6 months without menses) and resumption of menses. Results After excluding women with hysterectomies prior to cancer diagnosis, 1,043 women were eligible for analysis. Amenorrhea occurred in 31.6% of women. Among women treated with chemotherapy (n=596), older age at diagnosis (30–35 versus 20–24 years: adjusted odds ratio (aOR)=2.37, 95% confidence interval (CI): 1.30, 4.30) and nulligravidity (versus gravid: aOR=1.50, 95% CI: 1.02, 2.21) were risk factors for amenorrhea. Among amenorrheic women, menses resumed in most (70.0%), and resumption occurred within 2 years of treatment for 90.0% of women. Survivors of breast cancer were more likely resume menses at times greater than one year compared with lymphoma and pelvic-area cancers. Women diagnosed at older ages, those exposed to chemotherapy, and those exposed to any radiation experienced longer times to return of menses. Women who were older at diagnosis were more likely to have irregular cycles when menses returned. Conclusion Treatment-induced amenorrhea is common in cancer survivors although most women resume menses within 2 years. However, once resumed, older women are more likely to have irregular cycles. Age at diagnosis and pregnancy history affect the risk of amenorrhea. PMID:26658130

Adolescence and polycystic ovary syndrome: current concepts on diagnosis and treatment.

PubMed

Spritzer, P M; Motta, A B

2015-11-01

Adolescence is a time characterised by changes in reproductive hormones and menstrual patterns, which makes it difficult to diagnose polycystic ovary syndrome (PCOS) in this population. The diagnosis of PCOS has a great physical and psychosocial impact on the young person. Despite the importance of a diagnosis of PCOS at adolescence, data available are limited. This review focuses on analysing markers of PCOS diagnosis and possible treatments in adolescence. Although, during adolescence, diagnosis criteria of PCOS overlap with physiological changes including clinical manifestations of hyperandrogenism (acne and hirsutism), oligo/amenorrhoea, anovulation and ovarian microcysts, there is agreement that irregular menses and hyperandrogenaemia should be used to diagnose PCOS in this population. Moreover, considering that PCOS phenotype could change through the reproductive age and that adolescents display heterogeneous ovarian morphology, it has been proposed that diagnosis of PCOS should be confirmed after the age of 18. The first-line treatment for menstrual irregularity and hirsutism are oral contraceptive pills (OCPs) and for obesity and metabolic abnormalities are lifestyle changes. Insulin-sensitizer drugs, such as metformin, may be added to the treatment in the presence of metabolic alterations. Antiandrogen drugs may also be associated for treating moderate to severe hirsutism. During adolescence, physiological changes overlap with signs and symptoms of PCOS; thus the diagnosis criteria should be carefully considered. Regarding the treatment of adolescents with PCOS, non-pharmacological interventions include lifestyle changes. Pharmacological treatments comprise OCPs, antiandrogens and metformin, used isolated or combined. During adolescence, physiological changes overlap with signs and symptoms of PCOS; thus the diagnosis criteria should be carefully considered. Regarding the treatment of adolescents with PCOS, non-pharmacological interventions include lifestyle changes. Pharmacological treatments comprise OCPs, antiandrogens and metformin, used isolated or combined. © 2015 John Wiley & Sons Ltd.

Polycystic ovary syndrome: early diagnosis and intervention are necessary for fertility preservation in young women with endometrial cancer under 35 years of age.

PubMed

Okamura, Yoshinori; Saito, Fumitaka; Takaishi, Kiyomi; Motohara, Takeshi; Honda, Ritsuo; Ohba, Takashi; Katabuchi, Hidetaka

2017-01-01

Polycystic ovary syndrome (PCOS) is a significant risk factor for premenopausal endometrial cancer (EC) and/or atypical endometrial hyperplasia (AEH). The aim was to elucidate the clinical background and detailed menstrual history of EC and/or AEH in young women with PCOS. From January 2001 to December 2013, women under 35 years of age who had been diagnosed with EC and/or AEH and who had been treated at Kumamoto University Hospital, Japan, were recruited. The patients' clinical characteristics, clinical stages of EC and/or AEH, medication and operation methods, endocrine profiles, and menstrual history were assessed retrospectively. Of all the cases of EC and/or AEH, 25 (4.6%) were under 35 years of age. The mean age was 29.0 years and all the patients were nulligravida. The clinical stages of EC and/or AEH that were identified included: AEH (five cases), stage IA (18 cases), IB (one case), and IIIA (one case). Fourteen (56%) cases met the criteria for PCOS. Both the Body Mass Index and Homeostatic Model Assessment-insulin resistance were significantly higher in the patients with PCOS than in the patients without PCOS. Medroxyprogesterone acetate therapy was not effective for the patients with PCOS and they underwent a hysterectomy more often than the patients without PCOS. All the patients with PCOS exhibited irregular menstruation or amenorrhea, the mean duration of which was 13.1 years before PCOS and EC and/or AEH were diagnosed. Although both the patients with and without PCOS had irregular menstruation, the patients with PCOS were less likely to have fertility-sparing surgery than the patients without PCOS because they had more advanced disease or failed to respond to medroxyprogesterone acetate therapy.

Use of sonic tomography to detect and quantify wood decay in living trees1

PubMed Central

Gilbert, Gregory S.; Ballesteros, Javier O.; Barrios-Rodriguez, Cesar A.; Bonadies, Ernesto F.; Cedeño-Sánchez, Marjorie L.; Fossatti-Caballero, Nohely J.; Trejos-Rodríguez, Mariam M.; Pérez-Suñiga, José Moises; Holub-Young, Katharine S.; Henn, Laura A. W.; Thompson, Jennifer B.; García-López, Cesar G.; Romo, Amanda C.; Johnston, Daniel C.; Barrick, Pablo P.; Jordan, Fulvia A.; Hershcovich, Shiran; Russo, Natalie; Sánchez, Juan David; Fábrega, Juan Pablo; Lumpkin, Raleigh; McWilliams, Hunter A.; Chester, Kathleen N.; Burgos, Alana C.; Wong, E. Beatriz; Diab, Jonathan H.; Renteria, Sonia A.; Harrower, Jennifer T.; Hooton, Douglas A.; Glenn, Travis C.; Faircloth, Brant C.; Hubbell, Stephen P.

2016-01-01

Premise of the study: Field methodology and image analysis protocols using acoustic tomography were developed and evaluated as a tool to estimate the amount of internal decay and damage of living trees, with special attention to tropical rainforest trees with irregular trunk shapes. Methods and Results: Living trunks of a diversity of tree species in tropical rainforests in the Republic of Panama were scanned using an Argus Electronic PiCUS 3 Sonic Tomograph and evaluated for the amount and patterns of internal decay. A protocol using ImageJ analysis software was used to quantify the proportions of intact and compromised wood. The protocols provide replicable estimates of internal decay and cavities for trees of varying shapes, wood density, and bark thickness. Conclusions: Sonic tomography, coupled with image analysis, provides an efficient, noninvasive approach to evaluate decay patterns and structural integrity of even irregularly shaped living trees. PMID:28101433

On the nature of S II emission from Jupiter's hot plasma torus

NASA Technical Reports Server (NTRS)

Brown, R. A.; Shemansky, D. E.

1982-01-01

An effective electron temperature T(e) of 80,000 K is indicated by the Voyager 1 encounter Jupiter hot torus emission rates in the 6731, 1256, 911 and reclassified 765 A transitions of S II. A set of 53 measurements of the S II red line doublet obtained at 5.9 Jupiter radii shows strong, irregular fluctuations in intensity, but no variation in the line ratio. At this distance from Jupiter, the torus is found to be longitudinally uniform in density; this is consonant with Voyager UVS findings, but contrary to magnetic anomaly model predictions. It is suggested that presently unidentified ion-ion and/or iron-atom reactions are responsible for the S II component irregular variations, in view of the fact that electron properties are regular and variable only over a small range in the hot torus at 5.9 Jupiter radii.

Static and dynamic properties of two-dimensional Coulomb clusters.

PubMed

Ash, Biswarup; Chakrabarti, J; Ghosal, Amit

2017-10-01

We study the temperature dependence of static and dynamic responses of Coulomb interacting particles in two-dimensional confinements across the crossover from solid- to liquid-like behaviors. While static correlations that investigate the translational and bond orientational order in the confinements show the footprints of hexatic-like phase at low temperatures, dynamics of the particles slow down considerably in this phase, reminiscent of a supercooled liquid. Using density correlations, we probe long-lived heterogeneities arising from the interplay of the irregularity in the confinement and long-range Coulomb interactions. The relaxation at multiple time scales show stretched-exponential decay of spatial correlations in irregular traps. Temperature dependence of characteristic time scales, depicting the structural relaxation of the system, show striking similarities with those observed for the glassy systems, indicating that some of the key signatures of supercooled liquids emerge in confinements with lower spatial symmetries.

UV, optical and infrared properties of star forming galaxies

NASA Technical Reports Server (NTRS)

Huchra, John P.

1987-01-01

The UVOIR properties of galaxies with extreme star formation rates are examined. These objects seem to fall into three distinct classes which can be called (1) extragalactic H II regions, (2) clumpy irregulars, and (3) starburst galaxies. Extragalactic H II regions are dominated by recently formed stars and may be considered 'young' galaxies if the definition of young is having the majority of total integrated star formation occurring in the last billion years. Clumpy irregulars are bursts of star formation superposed on an old population and are probably good examples of stochastic star formation. It is possible that star formation in these galaxies is triggered by the infall of gas clouds or dwarf companions. Starburst galaxies are much more luminous, dustier and more metal rich than the other classes. These objects show evidence for shock induced star formation where shocks may be caused by interaction with massive companions or are the result of an extremely strong density wave.

Generation of Artificial Ionospheric Irregularities by the Modification of the Earth's Middle-Latitude Ionosphere by X-Mode Powerful HF Radio Waves

NASA Astrophysics Data System (ADS)

Frolov, Vladimir; Padokhin, Artem; Kunitsyn, Viacheslav; Akchurin, Adel; Bolotin, Ilya; Zykov, Evgeniy; Vertogradov, Gennadiy

Basing on experimental data obtained at the SURA heating facility by modification of the Earth’s middle-latitude ionosphere, we consider in the report some peculiarities of the generation of artificial plasma density irregularities when X-mode powerful waves (PW) are used for ionosphere pumping [1]. Experiments were carried out during 2008 - 2012 under quite ionospheric conditions (Sigma K_p = 10 - 30). Analysis of obtained experimental data has shown that: 1) In our measurements the generation of small-scale irregularities with l{_⊥} {≃} 10 - 20 m is not observed in contrast to analogous measurements conducted at the EISCAT-heater [2,3]. 2) The generation of irregularities with l{_⊥} {≃} 50 m - 3 km is mainly observed in evening and night hours. In these conditions their intensity is by 3 to 4 times below in comparison with the O-mode pumping. During day hours these irregularities are not detected due to both strong PW energy absorption in the lower ionosphere and forming a defocusing lens at altitudes of 130 - 150 km [4]. 3) The generation of irregularities with l{_⊥} {≥} 5 - 10 km is only observed in evening and night hours. In these conditions their intensity is by 10 times below in comparison with the O-mode pumping. 4) The generation of the irregularities with l{_⊥} {≥} 50 m is observed only when the PW reflects in the ionospheric F _{2} region. 5) Under day-time conditions the defocusing lens is forming at altitudes of about of 130 - 150 km when the ionosphere is pumping both X- and O- mode powerful waves [4]. Its horizontal size is determined by the HF beam. In our experiments [1] it was revealed that the stronger generation of irregularities with scale-lengths l{_⊥} {≃} 5 - 10 km is observed at the HF beam edge where the effective radiated power is of about 0.1 P _{max}. Such a “beam-edge” effect is also observed when the ionosphere is modified by O-mode PW. The enhancement of irregularity generation at the HF beam edge was considered in [5]. The work was supported by RFBR grants (## 12-05-00312, 13-02-12074, 13-02-12241, 14-05-31445, 14-05-00855, 14-05-10069), grant MK-2670.2014.5, and by the scientific program “Geophysics”. References: 1. Frolov et al. // Radiophys. Quant. Electron., Engl. Transl., 2013 (submitted for publication). 2. Blagovethshenskaya N.F., et al. // Geophys. Res. Lett., 2011. Vol. 38, L08802, doi:10.1029/2011GL046724. 3. Blagoveshchensraya N.F. et al. // J. Atmos. Sol.-Terr. Phys., 2013. Vol. 105-106, p. 231. 4. Boiko G.N. et al. // Radiophys. Quant. Electron., Engl. Transl., 1985. Vol. 28, No. 8, p. 960. 5. Kuo S., et al. // Geophys. Res. Lett., 2010. Vol. 37, L01101, doi:10.1029/2009GL041471.

Modeling the Electrode-Neuron Interface of Cochlear Implants: Effects of Neural Survival, Electrode Placement, and the Partial Tripolar Configuration

PubMed Central

Goldwyn, Joshua H.; Bierer, Steven M.; Bierer, Julie A.

2010-01-01

The partial tripolar electrode configuration is a relatively novel stimulation strategies that can generate more spatially focused electric fields than the commonly used monopolar configuration. Focused stimulation strategies should improve spectral resolution in cochlear implant users, but may also be more sensitive to local irregularities in the electrode-neuron interface. In this study, we develop a practical computer model of cochlear implant stimulation that can simulate neural activation in a simplified cochlear geometry and we relate the resulting patterns of neural activity to basic psychophysical measures. We examine how two types of local irregularities in the electrode-neuron interface, variations in spiral ganglion nerve density and electrode position within the scala tympani, affect the simulated neural activation patterns and how these patterns change with electrode configuration. The model shows that higher partial tripolar fractions activate more spatially restricted populations of neurons at all current levels and require higher current levels to excite a given number of neurons. We find that threshold levels are more sensitive at high partial tripolar fractions to both types of irregularities, but these effects are not independent. In particular, at close electrode-neuron distances, activation is typically more spatially localized which leads to a greater influence of neural dead regions. PMID:20580801

Morpho-physiological Characteristics of Dorsal Subicular Network in Mice after Pilocarpine Induced Status Epilepticus

PubMed Central

He, De Fu; Ma, Dong Liang; Tang, Yong Cheng; Engel, Jerome; Bragin, Anatol; Tang, Feng Ru

2010-01-01

The goal of this study was to examine morpho-physiological changes in the dorsal subiculum network in the mouse model of temporal lobe epilepsy using extracellular recording, juxtacellular and immunofluorescence double labeling, and anterograde tracing methods. A significant loss of total dorsal subicular neurons, particularly calbindin, parvalbumin (PV), and immunopositive interneurons, was found at 2 months after pilocarpine-induced status epilepticus (SE). However, the sprouting of axons from lateral entorhinal cortex (LEnt) was observed to contact with surviving subicular neurons. These neurons had two predominant discharge patterns: bursting and fast irregular discharges. The bursting neurons were mainly pyramidal cells, and their dendritic spine density and bursting discharge rates were increased significantly in SE mice compared to the control group. Fast irregular discharge neurons were PV-immunopositive interneurons, and had less dendritic spines in SE mice when compared to control mice. When LEnt was stimulated, bursting and fast irregular discharge neurons had much shorter latency and stronger excitatory response in SE mice compared to the control group. Our results illustrate that morpho-physiological changes in the dorsal subiculum could be part of a multilevel pathological network that occurs simultaneously in many brain areas to contribute to the generation of epileptiform activity. PMID:19298597

A multi-instrument case study of high-latitude ionospheric GNSS scintillation due to drifting plasma irregularities

NASA Astrophysics Data System (ADS)

van der Meeren, C.; Oksavik, K.; Moen, J. I.; Romano, V.

2013-12-01

For this study, GPS receiver scintillation and Total Electron Content (TEC) data from high-latitude locations on Svalbard have been combined with several other data sets, including the EISCAT Svalbard Radar (ESR) and allsky cameras, to perform a multi-instrument case study of high-latitude GPS ionospheric scintillations in relation to drifting plasma irregularities at night over Svalbard on 31 October 2011. Scintillations are rapid amplitude and phase fluctuations of electromagnetic signals. GNSS-based systems may be disturbed by ionospheric plasma irregularities and structures such as plasma patches (areas of enhanced electron density in the polar cap) and plasma gradients. When the GNSS radio signals propagate through such areas, in particular gradients, the signals experience scintillations that at best increases positioning errors and at worst may break the receiver's signal lock, potentially resulting in the GNSS receiver losing track of its position. Due to the importance of many GNSS applications, it is desirable to study the scintillation environment to understand the limitations of the GNSS systems. We find scintillation mainly localised to plasma gradients, with predominantly phase scintillation at the leading edge of patches and both phase and amplitude scintillation at the trailing edge. A single edge may also contain different scintillation types at different locations.

The Umov effect in application to an optically thin two-component cloud of cosmic dust

NASA Astrophysics Data System (ADS)

Zubko, Evgenij; Videen, Gorden; Zubko, Nataliya; Shkuratov, Yuriy

2018-04-01

The Umov effect is an inverse correlation between linear polarization of the sunlight scattered by an object and its geometric albedo. The Umov effect has been observed in particulate surfaces, such as planetary regoliths, and recently it also was found in single-scattering small dust particles. Using numerical modeling, we study the Umov effect in a two-component mixture of small irregularly shaped particles. Such a complex chemical composition is suggested in cometary comae and other types of optically thin clouds of cosmic dust. We find that the two-component mixtures of small particles also reveal the Umov effect regardless of the chemical composition of their end-member components. The interrelation between log(Pmax) and log(A) in a two-component mixture of small irregularly shaped particles appears either in a straight linear form or in a slightly curved form. This curvature tends to decrease while the index n in a power-law size distribution r-n grows; at n > 2.5, the log(Pmax)-log(A) diagrams are almost straight linear in appearance. The curvature also noticeably decreases with the packing density of constituent material in irregularly shaped particles forming the mixture. That such a relation exists suggest the Umov effect may also be observed in more complex mixtures.

The Umov effect in application to an optically thin two-component cloud of cosmic dust

NASA Astrophysics Data System (ADS)

Zubko, Evgenij; Videen, Gorden; Zubko, Nataliya; Shkuratov, Yuriy

2018-07-01

The Umov effect is an inverse correlation between linear polarization of the sunlight scattered by an object and its geometric albedo. The Umov effect has been observed in particulate surfaces, such as planetary regoliths, and recently it also was found in single-scattering small dust particles. Using numerical modelling, we study the Umov effect in a two-component mixture of small irregularly shaped particles. Such a complex chemical composition is suggested in cometary comae and other types of optically thin clouds of cosmic dust. We find that the two-component mixtures of small particles also reveal the Umov effect regardless of the chemical composition of their end-member components. The interrelation between log(Pmax) and log(A) in a two-component mixture of small irregularly shaped particles appears either in a straight linear form or in a slightly curved form. This curvature tends to decrease while the index n in a power-law size distribution r-n grows; at n > 2.5, the log(Pmax)-log(A) diagrams are almost straight linear in appearance. The curvature also noticeably decreases with the packing density of constituent material in irregularly shaped particles forming the mixture. That such a relation exists suggests the Umov effect may also be observed in more complex mixtures.

[McCune-Albright syndrome revealed by Blaschko-linear café-au-lait spots on the back].

PubMed

Jung, A-J; Soskin, S; Paris, F; Lipsker, D

2016-01-01

McCune-Albright syndrome is a rare sporadic disease defined by the triad of café-au-lait spots, fibrous dysplasia of bone and endocrine disorder. Diagnosis is classically confirmed by the presence of bone lesions or precocious puberty. We report a case of McCune-Albright syndrome diagnosed solely on the basis of the cutaneous signs. A four-year-old girl was seen in our clinic due to the presence of congenital café-au-lait spots on her back. These macules were irregular, with jagged borders, and were disposed in a broad band on the left shoulder and in the lumbar region, in a Blaschko-linear pattern. McCune-Albright syndrome was immediately suspected, despite the absence of other signs of the disease. Genetic assessment carried out a year and a half later confirmed the diagnosis, with arginine substitution at position 201 of Gs alpha protein. The child was still asymptomatic. Regular radiographic and endocrine assessments remained normal for three years until the sudden appearance at the age of seven years of precocious puberty and radiographic evidence of fibrous dysplasia of the right hand. Café-au-lait spots are very common in the general population. An underlying genetic disorder should only be sought when such spots are multiple. However, in the case of McCune-Albright syndrome, it is the irregular borders and the Blaschko-linear arrangement of the spots in broad irregular bands that are pathognomonic, reflecting as they do the genetic mosaicism characteristic of this disease. Copyright © 2015 Elsevier Masson SAS. All rights reserved.

The Scintillation Prediction Observations Research Task (SPORT) Mission

NASA Astrophysics Data System (ADS)

Spann, J. F.; Swenson, C.; Durão, O.; Loures, L.; Heelis, R. A.; Bishop, R. L.; Le, G.; Abdu, M. A.; Habash Krause, L.; De Nardin, C. M.; Fonseca, E.

2015-12-01

Structure in the charged particle number density in the equatorial ionosphere can have a profound impact on the fidelity of HF, VHF and UHF radio signals that are used for ground-to-ground and space-to-ground communication and navigation. The degree to which such systems can be compromised depends in large part on the spatial distribution of the structured regions in the ionosphere and the background plasma density in which they are embedded. In order to address these challenges it is necessary to accurately distinguish the background ionospheric conditions that favor the generation of irregularities from those that do not. Additionally we must relate the evolution of those conditions to the subsequent evolution of the irregular plasma regions themselves. The background ionospheric conditions are conveniently described by latitudinal profiles of the plasma density at nearly constant altitude, which describe the effects of ExB drifts and neutral winds, while the appearance and growth of plasma structure requires committed observations from the ground from at least one fixed longitude. This talk will present an international collaborative CubeSat mission called SPORT that stands for Scintillation Prediction Observations Research Task. This mission that will advance our understanding of the nature and evolution of ionospheric structures around sunset to improve predictions of disturbances that affect radio propagation and telecommunication signals. The science goals will be accomplished by a unique combination of satellite observations from a nearly circular middle inclination orbit and the extensive operation of ground based observations from South America near the magnetic equator. This approach promises Explorer class science at a CubeSat price.

The Scintillation Prediction Observations Research Task (SPORT) Mission

NASA Astrophysics Data System (ADS)

Spann, James; Le, Guan; Swenson, Charles; Denardini, Clezio Marcos; Bishop, Rebecca L.; Abdu, Mangalathayil A.; Cupertino Durao, Otavio S.; Heelis, Roderick; Loures, Luis; Krause, Linda; Fonseca, Eloi

2016-07-01

Structure in the charged particle number density in the equatorial ionosphere can have a profound impact on the fidelity of HF, VHF and UHF radio signals that are used for ground-to-ground and space-to-ground communication and navigation. The degree to which such systems can be compromised depends in large part on the spatial distribution of the structured regions in the ionosphere and the background plasma density in which they are embedded. In order to address these challenges it is necessary to accurately distinguish the background ionospheric conditions that favor the generation of irregularities from those that do not. Additionally we must relate the evolution of those conditions to the subsequent evolution of the irregular plasma regions themselves. The background ionospheric conditions are conveniently described by latitudinal profiles of the plasma density at nearly constant altitude, which describe the effects of ExB drifts and neutral winds, while the appearance and growth of plasma structure requires committed observations from the ground from at least one fixed longitude. This talk will present an international collaborative CubeSat mission called SPORT that stands for the Scintillation Prediction Observations Research Task. This mission will advance our understanding of the nature and evolution of ionospheric structures around sunset to improve predictions of disturbances that affect radio propagation and telecommunication signals. The science goals will be accomplished by a unique combination of satellite observations from a nearly circular middle inclination orbit and the extensive operation of ground based observations from South America near the magnetic equator. This approach promises Explorer class science at a CubeSat price.

The Scintillation Prediction Observations Research Task (SPORT) Mission

NASA Astrophysics Data System (ADS)

Spann, James; Swenson, Charles; Durão, Otavio; Loures, Luis; Heelis, Rod; Bishop, Rebecca; Le, Guan; Abdu, Mangalathayil; Krause, Linda; Nardin, Clezio; Fonseca, Eloi

2016-04-01

Structure in the charged particle number density in the equatorial ionosphere can have a profound impact on the fidelity of HF, VHF and UHF radio signals that are used for ground-to-ground and space-to-ground communication and navigation. The degree to which such systems can be compromised depends in large part on the spatial distribution of the structured regions in the ionosphere and the background plasma density in which they are embedded. In order to address these challenges it is necessary to accurately distinguish the background ionospheric conditions that favor the generation of irregularities from those that do not. Additionally we must relate the evolution of those conditions to the subsequent evolution of the irregular plasma regions themselves. The background ionospheric conditions are conveniently described by latitudinal profiles of the plasma density at nearly constant altitude, which describe the effects of ExB drifts and neutral winds, while the appearance and growth of plasma structure requires committed observations from the ground from at least one fixed longitude. This talk will present an international collaborative CubeSat mission called SPORT that stands for the Scintillation Prediction Observations Research Task. This mission will advance our understanding of the nature and evolution of ionospheric structures around sunset to improve predictions of disturbances that affect radio propagation and telecommunication signals. The science goals will be accomplished by a unique combination of satellite observations from a nearly circular middle inclination orbit and the extensive operation of ground based observations from South America near the magnetic equator. This approach promises Explorer class science at a CubeSat price.

Ultrasound-Diagnosed Tibia Stress Fracture: A Case Report.

PubMed

Amoako, Adae; Abid, Ayesha; Shadiack, Anthony; Monaco, Robert

2017-01-01

Stress fractures are a frequent cause of lower extremity pain in athletes, and especially in runners. Plain imaging has a low sensitivity. Magnetic resonance imaging (MRI) or bone scan scintigraphy is the criterion standard, but expensive. We present the case of a young female distance runner with left shin pain. Plain radiography was unremarkable. Ultrasound showed focal hyperechoic elevation of the periosteum with irregularity over the distal tibia and increased flow on Doppler. These findings were consistent with a distal tibia stress fracture and confirmed by MRI. Examination of our case will highlight the utility of considering an ultrasound for diagnosis of tibial stress fracture.

Cutaneous angiomatosis in a llama (Lama glama).

PubMed

Luppi, M M; Malta, M C C; Ocarino, N M; França, S A; Serakides, R

2010-01-01

Cutaneous angiomatosis was diagnosed in an adult female llama (Lama glama). Lesions were raised or plaque-like, erythematous, firm to soft in consistency and were observed on the face and skin of the axillary, abdominal, perineal and inguinal regions. The lesions were not painful or pruritic. Microscopical examination revealed an irregular parakeratotic lamellar hyperkeratosis associated with diffuse proliferation of arterioles and venules in the superficial dermis. Immunohistochemical analysis determined that the cells forming these vessels and perivascular cells expressed factor VIII-related antigen, vascular endothelial growth factor (VEGF), CD31 and smooth-muscle alpha-actin. These studies confirmed the diagnosis of cutaneous angiomatosis. Copyright 2009 Elsevier Ltd. All rights reserved.

Ultrasound-Diagnosed Tibia Stress Fracture: A Case Report

PubMed Central

Amoako, Adae; Abid, Ayesha; Shadiack, Anthony; Monaco, Robert

2017-01-01

Stress fractures are a frequent cause of lower extremity pain in athletes, and especially in runners. Plain imaging has a low sensitivity. Magnetic resonance imaging (MRI) or bone scan scintigraphy is the criterion standard, but expensive. We present the case of a young female distance runner with left shin pain. Plain radiography was unremarkable. Ultrasound showed focal hyperechoic elevation of the periosteum with irregularity over the distal tibia and increased flow on Doppler. These findings were consistent with a distal tibia stress fracture and confirmed by MRI. Examination of our case will highlight the utility of considering an ultrasound for diagnosis of tibial stress fracture. PMID:28469488

Beam-plasma instability in the presence of low-frequency turbulence. [during type 3 solar emission

NASA Technical Reports Server (NTRS)

Goldman, M. V.; Dubois, D. F.

1982-01-01

General equations are derived for a linear beam-plasma instability in the presence of low-frequency turbulence. Within a 'quasi-linear' statistical approximation, these equations contain Langmuir wave scattering, diffusion, resonant and nonresonant anomalous absorption, and a 'plasma laser' effect. It is proposed that naturally occurring density irregularities in the solar wind may stabilize the beam-unstable Langmuir waves which occur during type III solar emissions.

Congenital Panfollicular Nevus in a 6-Month-Old Girl.

PubMed

Duan, Linna; Antaya, Richard J; Ko, Christine J; Narayan, Deepak

2016-01-01

A 6-month-old girl presented with an irregular nodule on the right lateral neck. The lesion, which superficially resembled a lymphangioma or mastocytoma, had been present since birth but had recently been growing. The patient was referred for surgical resection. Microscopic findings were compatible with a recently described rare hamartoma termed "panfollicular nevus," which is a well-circumscribed lesion containing aberrantly differentiated, clustered hair follicles in high density. © 2016 Wiley Periodicals, Inc.

Study of Equatorial Ionospheric irregularities and Mapping of Electron Density Profiles and Ionograms

DTIC Science & Technology

2012-03-09

equation is a product of a complex basis vector in Jackson and a linear combination of plane wave functions. We convert both the amplitudes and the...wave function arguments from complex scalars to complex vectors . This conversion allows us to separate the electric field vector and the imaginary...magnetic field vector , because exponentials of imaginary scalars convert vectors to imaginary vectors and vice versa, while ex- ponentials of imaginary

Irregularities and Forecast Studies of Equatorial Spread

DTIC Science & Technology

2016-07-13

less certain and requires investigation. It should be possible to observe the Faraday rotation of the signals received at Jicamarca. This is another...indication of the line-integrated electron number 9 DISTRIBUTION A: Distribution approved for public release. density. Like the phase delay, the Faraday ...angle is a modulo-two-pi quantity that is best used to constrain the time evolution of the ionosphere. Both the Faraday angle and the phase delay are

X-ray lines as a density diagnostic in DT plasmas near 100x solid density

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bailey, D.S.

1977-10-19

The use of electron impact broadened resonance lines to diagnose near-term high density diagnostics is discussed. In particular, the question of how to choose seed and pusher materials to have discernible broadening effects while maintaining line visibility is discussed.

Female genital tuberculosis cases with distinct clinical symptoms: Four case reports

PubMed Central

Aslan, Gonul; Ulger, Mahmut; Ulger, Seda Tezcan; Durukan, Huseyin; Yazici, Faik Gurkan; Emekdas, Gurol

2018-01-01

Background: Tuberculosis (TB) is an infectious disease caused by Mycobacterium tuberculosis. Genital TB (GTB) is a form of extrapulmonary TB that occurs more frequently in women, in whom it classically presents in association with menstrual irregularity, pregnancy loss and short and long-term sequelae especially infertility in infected women. Patients with GTB are usually young women diagnosed during workup for infertility. GTB is rare in postmenopausal women and responsible for only approximately 1% of postmenopausal bleeding. In this study, we aimed to evaluate the laboratory, clinical and demographic characteristics of female GTB cases. Case: We presented four female GTB cases with distinct clinical symptoms. All patients have no history of TB, and no acid-fast bacilli were seen in smears prepared from the clinical materials of the patients. Histopathological examinations revealed granulomatous inflammation in all patients. Conclusion: In the light of the clinical features of these cases we aimed to emphasize that, female GTB must be taken into account in the patients with different clinical symptoms like postmenopausal bleeding, menometrorrhagia, infertility, and menstrual irregularities. We believe that these symptoms will be helpful for the diagnosis and treatment of female GTB. PMID:29675489

Endometrial endometrioid adenocarcinoma associated with primitive neuroectodermal tumour of the uterus: a poor prognostic subtype of uterine tumours.

PubMed

Bartosch, Carla; Vieira, Joana; Teixeira, Manuel R; Lopes, José Manuel

2011-12-01

Uterine primitive neuroectodermal tumours are extremely rare tumours. They can occur in pure form or combined with another component including endometrioid adenocarcinoma. We aimed to review the clinical impact of neuroectodermal phenotype in uterine tumours, after we recently diagnosed one such case. A 58-year-old female presented with irregular vaginal bleeding. Ultrasonography and CT showed the presence of a large uterine mass with irregular contours. At laparotomy it was found to extend to the right ureter, sigmoid colon and some small intestinal loops. Microscopic examination revealed that the tumour consisted of an endometrioid adenocarcinoma component merging with an extensive neuroectodermal component. No EWSR1 or FUS rearrangement was found in the two tumour components. The patient received two courses of chemotherapy but died 11 months after the initial diagnosis. We reviewed the morphological and molecular criteria for the diagnosis of uterine primitive neuroectodermal tumours published in the literature. We conclude that regardless of the detection of an EWSR1 rearrangement, the presence of a neuroectodermal differentiation component in these rare uterine tumours is a marker of aggressive behaviour, and its presence should be highlighted in the diagnosis.

The prevalence of endocrinopathies among Lebanese women presenting with hirsutism to an endocrine clinic.

PubMed

Zreik, R S; Nasrallah, Mona P

2014-01-01

Hirsutism is a common condition in women characterized by excessive growth of terminal hair in a male pattern distribution. It may be a manifestation of underlying pathologies. Since there is no data published about the prevalence of endocrinopathies among hirsute women in Lebanon, this study's aim was to reveal the most common etiologies of hirsutism in this population. The study is a descriptive review of cases of 160 females with hirsutism presenting to a single endocrinologist clinic. Data about history, physical exam, blood tests and imaging results were collected after review of medical charts. Out of the 160 cases reviewed, 14 females (8.8%) were left undiagnosed. Out of 146 subjects diagnosed, 72.6% were found to have polycystic ovary syndrome (PCOS), 18.5% idiopathic hirsutism (IH), 4.6% non-classic congenital adrenal hyperplasia, 2.6% hyperprolactinemia, 0.6% Cushing's syndrome and 0.6% hypothyroidism. A higher percentage of irregular menses and a trend for overweight were found among the PCOS group. PCOS remains the most common cause of hirsutism in an endocrine referral clinic, similar to other populations. A low threshold for diagnostic workup is in order, especially when there is associated menstrual irregularity or overweight.

Propagation Diagnostic Simulations Using High-Resolution Equatorial Plasma Bubble Simulations

NASA Astrophysics Data System (ADS)

Rino, C. L.; Carrano, C. S.; Yokoyama, T.

2017-12-01

In a recent paper, under review, equatorial-plasma-bubble (EPB) simulations were used to conduct a comparative analysis of the EPB spectra characteristics with high-resolution in-situ measurements from the C/NOFS satellite. EPB realizations sampled in planes perpendicular to magnetic field lines provided well-defined EPB structure at altitudes penetrating both high and low-density regions. The average C/NOFS structure in highly disturbed regions showed nearly identical two-component inverse-power-law spectral characteristics as the measured EPB structure. This paper describes the results of PWE simulations using the same two-dimensional cross-field EPB realizations. New Irregularity Parameter Estimation (IPE) diagnostics, which are based on two-dimensional equivalent-phase-screen theory [A theory of scintillation for two-component power law irregularity spectra: Overview and numerical results, by Charles Carrano and Charles Rino, DOI: 10.1002/2015RS005903], have been successfully applied to extract two-component inverse-power-law parameters from measured intensity spectra. The EPB simulations [Low and Midlatitude Ionospheric Plasma DensityIrregularities and Their Effects on Geomagnetic Field, by Tatsuhiro Yokoyama and Claudia Stolle, DOI 10.1007/s11214-016-0295-7] have sufficient resolution to populate the structure scales (tens of km to hundreds of meters) that cause strong scintillation at GPS frequencies. The simulations provide an ideal geometry whereby the ramifications of varying structure along the propagation path can be investigated. It is well known path-integrated one-dimensional spectra increase the one-dimensional index by one. The relation requires decorrelation along the propagation path. Correlated structure would be interpreted as stochastic total-electron-content (TEC). The simulations are performed with unmodified structure. Because the EPB structure is confined to the central region of the sample planes, edge effects are minimized. Consequently, the propagated signal phase can be comparted to path-integrated phase for evaluating TEC extraction. Only the frequency dependence of phase scintillation distinguishes phase scintillation. The simulations allow scale-dependent exploration of remote-sensing diagnostics.

Effects of Quercetin in a Mouse Model of Experimental Dry Eye.

PubMed

Oh, Ha Na; Kim, Chae Eun; Lee, Ji Hyun; Yang, Jae Wook

2015-09-01

To evaluate the effect of treatment with quercetin in a mouse model of dry eye. 0.5% quercetin eye drops were prepared and an experimental dry eye model was induced in NOD.B10.H2(b) mice through desiccation stress. The mice were divided into 3 groups according to the treatment regimen: the DS 10D group (desiccation stress for 10 days), the phosphate buffered saline (PBS) group, and the quercetin group. Tear volumes and corneal irregularity scores were measured at 3, 5, 7, and 10 days after treatment. Hematoxylin and eosin staining, periodic acid-Schiff staining, and immunohistochemistry were performed at the end of the experiment. The quercetin group had increased tear volumes (0.2 ± 0.03 μm, P < 0.05) and decreased corneal irregularity scores (0.7 ± 0.6, P < 0.05) compared with those of the PBS group. On histological examination, the quercetin group exhibited restored smooth corneal surfaces without detaching corneal epithelial cells and had significantly increased goblet cell density (13.8 ± 0.8 cells/0.1 mm², P < 0.05) compared with the PBS group. The quercetin group also exhibited significant declines of MMP-2 (5.1-fold of control, P < 0.01), MMP-9 (2.5-fold of control, P < 0.01), ICAM-1 (2.2-fold of control, P < 0.01), and VCAM-1 (2.3-fold of control, P < 0.01) levels in the lacrimal gland than did the PBS group. Topical application of quercetin can help to improve ocular surface disorders of dry eye not only by decreasing the corneal surface irregularity but also by increasing the tear volume and goblet cell density. Moreover, quercetin has the potential for use in eye drops as a treatment for dry eye disease with antiinflammatory effects on the lacrimal functional unit.

Characterization of Ionospheric Dynamics Over The East African Dip Equatorial Region Using GPS-Derived Total Electron Content.

NASA Astrophysics Data System (ADS)

Olwendo, J. O.

2016-12-01

Through a linear combination of GPS satellite range and phase measurement observed on two carrier frequencies by terrestrial based GPS receivers, the ionospheric total electron content (TEC) along oblique GPS signal path can be quantified. Using Adjusted Spherical Harmonic (ASHA) expansion, regional TEC maps over the East Africa sector has been achieved. The observed TEC has been used to evaluate the performance of IRI2007 and NeQuick 2 models over the region. Ionospheric irregularities have been measured and the plasma drift velocity and the East-West extent of the irregularities have also been analyzed by using a Very High Frequency (VHF) receiver system that is closely spaced. The hourly TEC images developed have shown that the Southern Equatorial Ionization Anomaly (EIA) crest over the East African sector lies within the Kenyan region, and the occurrence of scintillation is dependent on how well the anomaly crest forms. Scintillation occurrences are intense at and around the edges of EIA crest due to the presence of high ambient electron densities and sharp TEC depletions. Simultaneous recording of amplitude scintillations at VHF and L-band frequencies reveal two distinct types of scintillation namely; the Plasma Bubble Induced (PBI) and the Bottom Side Sinusoidal (BSS). The PBI scintillations are characterized by high intensity during the post-sunset hours of the equinoctial months and appear at both VHF and L-band frequencies. The BSS type are associated with VHF scintillation and are characterized by long duration patches and often exhibit Fresnel oscillation on the roll portion of the power spectrum, which suggest a weak scattering from thin screen irregularities. The occurrence of post-midnight L-band scintillation events which are not linked to pre-midnight scintillation observations raises fundamental question on the mechanism and source of electric fields driving the plasma depletion under conditions of very low background electron density.

Features of High-Latitude Ionospheric Irregularities Development as Revealed by Ground-Based GPS Observations, Satellite-Borne GPS Observations and Satellite In Situ Measurements over the Territory of Russia during the Geomagnetic Storm on March 17-18, 2015

NASA Astrophysics Data System (ADS)

Zakharenkova, I. E.; Cherniak, Iu. V.; Shagimuratov, I. I.; Klimenko, M. V.

2018-01-01

The dynamic picture of the response of the high- and mid-latitude ionosphere to the strong geomagnetic disturbances on March 17-18, 2015, has been studied with ground-based and satellite observations, mainly, by transionospheric measurements of delays of GPS (Global Positioning System) signals. The advantages of the joint use of ground-based GPS measurements and GPS measurements on board of the Swarm Low-Earth-Orbit satellite mission for monitoring of the appearance of ionospheric irregularities over the territory of Russia are shown for the first time. The results of analysis of ground-based and space-borne GPS observations, as well as satellite, in situ measurements, revealed large-scale ionospheric plasma irregularities observed over the territory of Russia in the latitude range of 50°-85° N during the main phase of the geomagnetic storm. The most intense ionospheric irregularities were detected in the auroral zone and in the region of the main ionospheric trough (MIT). It has been found that sharp changes in the phase of the carrier frequency of the navigation signal from all tracked satellites were recorded at all GPS stations located to the North from 55° MLAT. The development of a deep MIT was related to dynamic processes in the subauroral ionosphere, in particular, with electric fields of the intense subauroral polarization stream. Analysis of the electron and ion density values obtained by instruments on board of the Swarm and DMSP satellites showed that the zone of highly structured auroral ionosphere extended at least to heights of 850-900 km.

Relation of decorrelated transionospheric GPS signal fluctuations from two stations in the northern anomaly crest region with equatorial ionospheric dynamics

NASA Astrophysics Data System (ADS)

Paul, K. S.; Paul, A.

2017-05-01

The ionosphere around the northern crest of the equatorial ionization anomaly (EIA) and beyond exhibits rapid temporal as well as spatial development of ionization density irregularities during postsunset hours. A GPS campaign was conducted during September 2012 and April 2013 from the Institute of Radio Physics and Electronics, Calcutta (22.58°N, 88.38°E geographic; magnetic dip: 32°N), and North Bengal University (NBU), Siliguri (26.72°N, 88.39°E geographic, magnetic dip: 39.49°N) in India in order to assess and quantify differences, if any, in the nature of carrier to noise ratio (C/N0) fluctuations observed on the same satellite link around the same time interval from these stations. Significant decorrelation of the received signals was found when tracking the same satellite vehicle (SV) link from these stations during periods of scintillations. Low values of correlation coefficient of C/N0 at L1 frequency recorded on the same SV link at these two stations were found to correspond with high irregularity characteristic velocities. North-south spatial displacement rates of the impact of ionospheric irregularities were calculated based on coordinated GPS observations which followed an increasing trend with irregularity characteristic velocities measured at VHF. Values of characteristic velocities in excess of 36 m/s were also found to result in large receiver position deviations 3.5-4.0 m during periods of scintillations. Information related to time lag associated with occurrence of scintillations on the same SV link observed from two stations could be useful for improving performance of transionospheric satellite-based position determination techniques.

Matrix cracking with irregular fracture fronts as observed in fiber reinforced ceramic composites

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hu, K.X.; Yeh, C.P.; Wyatt, K.W.

1998-01-01

As a result of matrix cracking in fiber reinforced composites, fracture planforms assume a wide variation of profiles due to the fact that fiber bridging strongly affects the behavior of local crack fronts. This observation raises the question on the legitimacy of commonly used penny-shaped crack solutions when applied to fiber reinforced composites. Accordingly, investigation of the effects of fracture front profiles on mechanical responses is the thrust of this paper. The authors start with the solution of a penny-shaped crack in a unidirectional, fiber reinforced composite, which demonstrates necessity of considering wavy fracture fronts in fiber reinforced composites. Amore » theoretical framework for fiber reinforced composites with irregular fracture fronts due to matrix cracking is then established via a micromechanics model. The difference between small crack-size matrix cracking and large crack-size matrix cracking is investigated in detail. It is shown that the bridging effect is insignificant when matrix crack size is small and solution of effective property are obtained using Mori-Tanaka`s method by treating cracks and reinforcing fibers as distinct, but interacting phases. When the crack size becomes large, the bridging effects has to be taken into consideration. With bridging tractions obtained in consistency with the micromechanics solution, and corresponding crack energy backed out, the effective properties are obtained through a modification of standard Mori-Tanaka`s treatment of multiphase composites. Analytical solutions show that the generalization of a crack density of a penny-shaped planform is insufficient in describing the effective responses of fiber-reinforced composites with matrix cracking. Approximate solutions that account for the effects of the irregularity of crack planforms are given in closed forms for several irregular crack planforms, including cracks of cross rectangle, polygon and rhombus.« less

In vivo confocal microscopy of meibomian glands in primary blepharospasm: A prospective case-control study in a Chinese population.

PubMed

Lin, Tong; Gong, Lan

2016-06-01

The aim of the study was to evaluate the morphological changes of meibomian glands (MGs) in primary blepharospasm (PBS) by in vivo laser scanning confocal microscopy (LSCM) and to investigate the correlations between clinical data of PBS and LSCM parameters of MGs. This prospective and case-control study recruited 30 consecutive PBS patients and 30 age- and gender-matched healthy controls. After questionnaire assessments of ocular surface disease index (OSDI), Jankovic rating scale, and blepharospasm disability index, all subjects underwent blink rate evaluation, tear film break-up time (TBUT), corneal fluorescein staining (CFS), Schirmer test, MG expressibility, meibum quality, MG dropout, and LSCM examination of the MGs. The main LSCM outcomes included the mean MG acinar area and density, orifice diameter, meibum secretion reflectivity, acinar irregularity, and inhomogeneity of interstice and acinar wall. The PBS patients had significantly higher blink rate, higher OSDI and CFS scores, lower TBUT and Schirmer test value, and worse MG expressibility than the controls (All P < 0.05), whereas meibum quality showed no difference (P > 0.05). The PBS patients showed lower values of MG acinar area, orifice diameter and meibum secretion reflectivity, and higher scores of acinar irregularity and inhomogeneity of interstices than the controls (All P < 0.05). For the PBS patients, the severity of blepharospasm evaluated by JCR scale was strong correlated with MG acinar area (P < 0.001), orifice diameter (P = 0.002), meibum secretion reflectivity (P = 0.002), and MG acinar irregularity (P = 0.013). The MG expressibility was significantly correlated to MG acinar area (P = 0.039), orifice diameter (P < 0.001), and MG acinar irregularity (P = 0.014). The OSDI score was moderate correlated with MG acinar irregularity (P = 0.016), whereas the TBUT value was positively correlated with MG acinar area (P = 0.045) and negatively correlated to MG acinar irregularity (P = 0.016). The CFS score was negatively correlated to MG orifice diameter (P = 0.008). The LSCM provided a noninvasive tool for in vivo histopathologic studies of MGs in PBS patients. The excessive constriction of lid muscles closely related to MG morphological alterations of PBS, which offered a new research approach to interpret the interactional mechanism between dry eye and PBS.

Sporadic-E Studies by Ionospheric Scintillation Using Ground-Based GPS and Radio Occultation Measurements

NASA Astrophysics Data System (ADS)

Seif, A.; Liu, T. J. Y.; Mannucci, A. J.; Carter, B. A.; Norman, R.

2016-12-01

The Global Navigation Satellite System (GNSS) based radio occultation (RO) technique provides an ideal limb-viewing geometry from space for studying the occurrence of sporadic E (Es). This study focuses on the detection and analysis of Es from RO measurements, to conclusively show the presence of Es's relationship with daytime scintillation. We bring two data sets to bear, using GNSS signal transmissions received on the ground and from space, which provide a unique opportunity to retrieve information about Es. RO signatures of Es and in GHz scintillation are not the same as ground-based signatures of Es. The viewing geometries are approximately orthogonal, which means the irregularity sources are not the same. That is, irregularities responsible for RO scintillations are essentially in a vertical plane, whereas those responsible for ground-based scintillations are essentially in a horizontal plane. Hence, complementary information is available regarding plasma structure in an Es patch. An analysis of combined data sets should prove to be a profitable avenue for research. In this study, we present the occurrence of scintillation using GPS Ionospheric Scintillation and Total Electron Content Monitor (GISTM) systems from two equatorial stations UKM (2.55°N, 101.46°E), and Langkawi (6.19°N, 99.51°E) in Malaysia. To better understand scale size irregularities as well as identify the occurrence of Es, we use COSMIC RO data. Two key findings coming out from our study are 1) According to the characteristics of daytime scintillation analyzed at, UKM and Langkawi stations, scintillation shows no significant TEC depletions and ROTI enhancements. The finding that ROTI does not exceed 0.5 TECU/min during daytime implies that large scale ionospheric irregularities with a scale length of a few kilometers do not exist at these stations. This is a piece of evidence which positively supports that daytime scintillation shows irregularities consistent with thin layer Es and supports the interpretation that a thin layer Es is responsible for producing daytime scintillation 2) The results obtained from GNSS RO measurements provide information on the existence of altitude and intensity of electron density irregularities at ionospheric E region height. This indicates that Es is associated with daytime GHz scintillation.

In vivo confocal microscopy of meibomian glands in primary blepharospasm

PubMed Central

Lin, Tong; Gong, Lan

2016-01-01

Abstract The aim of the study was to evaluate the morphological changes of meibomian glands (MGs) in primary blepharospasm (PBS) by in vivo laser scanning confocal microscopy (LSCM) and to investigate the correlations between clinical data of PBS and LSCM parameters of MGs. This prospective and case–control study recruited 30 consecutive PBS patients and 30 age- and gender-matched healthy controls. After questionnaire assessments of ocular surface disease index (OSDI), Jankovic rating scale, and blepharospasm disability index, all subjects underwent blink rate evaluation, tear film break-up time (TBUT), corneal fluorescein staining (CFS), Schirmer test, MG expressibility, meibum quality, MG dropout, and LSCM examination of the MGs. The main LSCM outcomes included the mean MG acinar area and density, orifice diameter, meibum secretion reflectivity, acinar irregularity, and inhomogeneity of interstice and acinar wall. The PBS patients had significantly higher blink rate, higher OSDI and CFS scores, lower TBUT and Schirmer test value, and worse MG expressibility than the controls (All P < 0.05), whereas meibum quality showed no difference (P > 0.05). The PBS patients showed lower values of MG acinar area, orifice diameter and meibum secretion reflectivity, and higher scores of acinar irregularity and inhomogeneity of interstices than the controls (All P < 0.05). For the PBS patients, the severity of blepharospasm evaluated by JCR scale was strong correlated with MG acinar area (P < 0.001), orifice diameter (P = 0.002), meibum secretion reflectivity (P = 0.002), and MG acinar irregularity (P = 0.013). The MG expressibility was significantly correlated to MG acinar area (P = 0.039), orifice diameter (P < 0.001), and MG acinar irregularity (P = 0.014). The OSDI score was moderate correlated with MG acinar irregularity (P = 0.016), whereas the TBUT value was positively correlated with MG acinar area (P = 0.045) and negatively correlated to MG acinar irregularity (P = 0.016). The CFS score was negatively correlated to MG orifice diameter (P = 0.008). The LSCM provided a noninvasive tool for in vivo histopathologic studies of MGs in PBS patients. The excessive constriction of lid muscles closely related to MG morphological alterations of PBS, which offered a new research approach to interpret the interactional mechanism between dry eye and PBS. PMID:27281086

Astrometric positions for 18 irregular satellites of giant planets from 23 years of observations

NASA Astrophysics Data System (ADS)

Gomes-Júnior, A. R.; Assafin, M.; Vieira-Martins, R.; Arlot, J.-E.; Camargo, J. I. B.; Braga-Ribas, F.; da Silva Neto, D. N.; Andrei, A. H.; Dias-Oliveira, A.; Morgado, B. E.; Benedetti-Rossi, G.; Duchemin, Y.; Desmars, J.; Lainey, V.; Thuillot, W.

2015-08-01

Context. The irregular satellites of the giant planets are believed to have been captured during the evolution of the solar system. Knowing their physical parameters, such as size, density, and albedo is important for constraining where they came from and how they were captured. The best way to obtain these parameters are observations in situ by spacecrafts or from stellar occultations by the objects. Both techniques demand that the orbits are well known. Aims: We aimed to obtain good astrometric positions of irregular satellites to improve their orbits and ephemeris. Methods: We identified and reduced observations of several irregular satellites from three databases containing more than 8000 images obtained between 1992 and 2014 at three sites (Observatório do Pico dos Dias, Observatoire de Haute-Provence, and European Southern Observatory - La Silla). We used the software Platform for Reduction of Astronomical Images Automatically (PRAIA) to make the astrometric reduction of the CCD frames. The UCAC4 catalog represented the International Celestial Reference System in the reductions. Identification of the satellites in the frames was done through their ephemerides as determined from the SPICE/NAIF kernels. Some procedures were followed to overcome missing or incomplete information (coordinates, date), mostly for the older images. Results: We managed to obtain more than 6000 positions for 18 irregular satellites: 12 of Jupiter, 4 of Saturn, 1 of Uranus (Sycorax), and 1 of Neptune (Nereid). For some satellites the number of obtained positions is more than 50% of what was used in earlier orbital numerical integrations. Conclusions: Comparison of our positions with recent JPL ephemeris suggests there are systematic errors in the orbits for some of the irregular satellites. The most evident case was an error in the inclination of Carme. Position tables are only available at the CDS via anonymous ftp to http://cdsarc.u-strasbg.fr (ftp://130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/580/A76 and IAU NSDC database at http://www.imcce.fr/nsdcPartially based on observations made at Laboratório Nacional de Astrofísica (LNA), Itajubá-MG, Brazil.Partially based on observations through the ESO runs 079.A-9202(A), 075.C-0154, 077.C-0283 and 079.C-0345.Partially based on observations made at Observatoire de Haute Provence (OHP), 04870 Saint-Michel l'observatoire, France.

Arecibo - HF experiments in the E_region

NASA Astrophysics Data System (ADS)

Nossa, E.; Jain, K.; Sulzer, M. P.; Perillat, P.

2017-12-01

The new Arecibo Observatory - HF facility started operations in 2015. The HF facility is fully operational, acquiring consecutive days of data without unwanted interruptions. It has a maximum transmitted power of 600kW, with center frequencies at 5.125 MHz and 8.175 MHz. The 8.175 (5.125) MHz band frequency has a gain of 25.5 (22) dB and HPBW of 8.5 (13) degrees. The effects of the HF experiments in the ionosphere are being observed with the Arecibo incoherent scatter radar (ISR). The ISR has two beams that simultaneously could sense the modified region and the region outside of the affected volume. The ISR has height resolution of 300 m. and allows to observe from altitudes 95 km to the topside ionosphere. Observation of the E-region - HF experiments are sparse but possible at Arecibo. High ionization at a height 100 km are needed to modify the region artificially. This paper presents examples of E-region enhanced plasma lines (See Figure). Diagnostic of the layers is made using the ISR to estimate electron density, temperatures, ion drifts, among others. The data shows exceptional modifications of the ionosphere that range from creating artificial cavities and layers, induced irregularities, substantial variations in temperature profiles to enhanced ion and plasma densities.Previously, the HF experiments were performed to study specific effects in a narrow region. However, the extent of the data collected with the ISR during 2017 is revealing new features and different kind of forces that artificially modify extended regions of the ionosphere. This paper exhibits examples where the interaction between the E and F-region when HF experiments are evident. A theory of a correlation between the two layers due to different conductivities is explored to illustrate how the enhancement of irregularities is produced and maintained over time. Examples of strong artificially induced irregularities formed at F-region heights when Sporadic E-layer is present are shown to support the theory.The Figure shows an enhanced plasma line for the diurnal E-region. For this HF experiment, the plasma density increased from 3.6 MHz to 5.1MHz (which corresponds to the HF frequency). The vertical lines observed in the Figure are artifacts from the data, as well as the fake enhanced plasma lines at frequencies different than the HF frequency.

Characteristics and sources of the electron density irregularities in the mid latitude E and Fregions

DTIC Science & Technology

2017-05-10

ASTRONOMY &SPACE SCIENCE INSTITUTE Final Report 05/10/2017 DISTRIBUTION A: Distribution approved for public release. AF Office Of Scientific Research...kasi.re.kr - Institution : Korea Astronomy and Space Science Institute - Mailing Address : 776, Daedeokdae-ro, Yuseong-gu, Daejeon, Republic of...Youngsil Kwak 5d.  PROJECT NUMBER 5e.  TASK NUMBER 5f.  WORK UNIT NUMBER 7. PERFORMING ORGANIZATION NAME(S) AND ADDRESS(ES) KOREA ASTRONOMY &SPACE SCIENCE

Fully-relativistic full-potential multiple scattering theory: A pathology-free scheme

NASA Astrophysics Data System (ADS)

Liu, Xianglin; Wang, Yang; Eisenbach, Markus; Stocks, G. Malcolm

2018-03-01

The Green function plays an essential role in the Korringa-Kohn-Rostoker(KKR) multiple scattering method. In practice, it is constructed from the regular and irregular solutions of the local Kohn-Sham equation and robust methods exist for spherical potentials. However, when applied to a non-spherical potential, numerical errors from the irregular solutions give rise to pathological behaviors of the charge density at small radius. Here we present a full-potential implementation of the fully-relativistic KKR method to perform ab initio self-consistent calculation by directly solving the Dirac differential equations using the generalized variable phase (sine and cosine matrices) formalism Liu et al. (2016). The pathology around the origin is completely eliminated by carrying out the energy integration of the single-site Green function along the real axis. By using an efficient pole-searching technique to identify the zeros of the well-behaved Jost matrices, we demonstrated that this scheme is numerically stable and computationally efficient, with speed comparable to the conventional contour energy integration method, while free of the pathology problem of the charge density. As an application, this method is utilized to investigate the crystal structures of polonium and their bulk properties, which is challenging for a conventional real-energy scheme. The noble metals are also calculated, both as a test of our method and to study the relativistic effects.

Radar observations of density gradients, electric fields, and plasma irregularities near polar cap patches in the context of the gradient-drift instability

NASA Astrophysics Data System (ADS)

Lamarche, Leslie J.; Makarevich, Roman A.

2017-03-01

We present observations of plasma density gradients, electric fields, and small-scale plasma irregularities near a polar cap patch made by the Super Dual Auroral Radar Network radar at Rankin Inlet (RKN) and the northern face of Resolute Bay Incoherent Scatter Radar (RISR-N). RKN echo power and occurrence are analyzed in the context of gradient-drift instability (GDI) theory, with a particular focus on the previously uninvestigated 2-D dependencies on wave propagation, electric field, and gradient vectors, with the latter two quantities evaluated directly from RISR-N measurements. It is shown that higher gradient and electric field components along the wave vector generally lead to the higher observed echo occurrence, which is consistent with the expected higher GDI growth rate, but the relationship with echo power is far less straightforward. The RKN echo power increases monotonically as the predicted linear growth rate approaches zero from negative values but does not continue this trend into positive growth rate values, in contrast with GDI predictions. The observed greater consistency of echo occurrence with GDI predictions suggests that GDI operating in the linear regime can control basic plasma structuring, but measured echo strength may be affected by other processes and factors, such as multistep or nonlinear processes or a shear-driven instability.

Accumulate-Repeat-Accumulate-Accumulate-Codes

NASA Technical Reports Server (NTRS)

Divsalar, Dariush; Dolinar, Sam; Thorpe, Jeremy

2004-01-01

Inspired by recently proposed Accumulate-Repeat-Accumulate (ARA) codes [15], in this paper we propose a channel coding scheme called Accumulate-Repeat-Accumulate-Accumulate (ARAA) codes. These codes can be seen as serial turbo-like codes or as a subclass of Low Density Parity Check (LDPC) codes, and they have a projected graph or protograph representation; this allows for a high-speed iterative decoder implementation using belief propagation. An ARAA code can be viewed as a precoded Repeat-and-Accumulate (RA) code with puncturing in concatenation with another accumulator, where simply an accumulator is chosen as the precoder; thus ARAA codes have a very fast encoder structure. Using density evolution on their associated protographs, we find examples of rate-lJ2 ARAA codes with maximum variable node degree 4 for which a minimum bit-SNR as low as 0.21 dB from the channel capacity limit can be achieved as the block size goes to infinity. Such a low threshold cannot be achieved by RA or Irregular RA (IRA) or unstructured irregular LDPC codes with the same constraint on the maximum variable node degree. Furthermore by puncturing the accumulators we can construct families of higher rate ARAA codes with thresholds that stay close to their respective channel capacity thresholds uniformly. Iterative decoding simulation results show comparable performance with the best-known LDPC codes but with very low error floor even at moderate block sizes.

A model of Saturn inferred from its measured gravitational field

NASA Astrophysics Data System (ADS)

Kong, Dali; Zhang, Keke; Schubert, Gerald; Anderson, John D.

2018-04-01

We present an interior model of Saturn with an ice-rock core, a metallic region, an outer molecular envelope and a thin transition layer between the metallic and molecular regions. The shape of Saturn’s 1 bar surface is irregular and determined fully self-consistently by the required equilibrium condition. While the ice-rock core is assumed to have a uniform density, three different equations of state are adopted for the metallic, molecular and transition regions. The Saturnian model is constrained by its known mass, its known equatorial and polar radii, and its known zonal gravitational coefficients, J 2n , n = 1, 2, 3. The model produces an ice-rock core with equatorial radius 0.203 R S, where R S is the equatorial radius of Saturn at the 1-bar pressure surface; the core density ρ c = 10388.1 kgm‑3 corresponding to 13.06 Earth masses; and an analytical expression describing the Saturnian irregular shape of the 1-bar pressure level. The model also predicts the values of the higher-order gravitational coefficients, J 8, J 10 and J 12, for the hydrostatic Saturn and suggests that Saturn’s convective dynamo operates in the metallic region approximately defined by 0.2 R S < r e < 0.7 R S, where r e denotes the equatorial radial distance from the Saturnian center of figure.

Fully-relativistic full-potential multiple scattering theory: A pathology-free scheme

DOE Office of Scientific and Technical Information (OSTI.GOV)

Liu, Xianglin; Wang, Yang; Eisenbach, Markus

The Green function plays an essential role in the Korringa–Kohn–Rostoker(KKR) multiple scattering method. In practice, it is constructed from the regular and irregular solutions of the local Kohn–Sham equation and robust methods exist for spherical potentials. However, when applied to a non-spherical potential, numerical errors from the irregular solutions give rise to pathological behaviors of the charge density at small radius. Here we present a full-potential implementation of the fully-relativistic KKR method to perform ab initio self-consistent calculation by directly solving the Dirac differential equations using the generalized variable phase (sine and cosine matrices) formalism Liu et al. (2016). Themore » pathology around the origin is completely eliminated by carrying out the energy integration of the single-site Green function along the real axis. Here, by using an efficient pole-searching technique to identify the zeros of the well-behaved Jost matrices, we demonstrated that this scheme is numerically stable and computationally efficient, with speed comparable to the conventional contour energy integration method, while free of the pathology problem of the charge density. As an application, this method is utilized to investigate the crystal structures of polonium and their bulk properties, which is challenging for a conventional real-energy scheme. The noble metals are also calculated, both as a test of our method and to study the relativistic effects.« less

Fully-relativistic full-potential multiple scattering theory: A pathology-free scheme

DOE PAGES

Liu, Xianglin; Wang, Yang; Eisenbach, Markus; ...

2017-10-28

The Green function plays an essential role in the Korringa–Kohn–Rostoker(KKR) multiple scattering method. In practice, it is constructed from the regular and irregular solutions of the local Kohn–Sham equation and robust methods exist for spherical potentials. However, when applied to a non-spherical potential, numerical errors from the irregular solutions give rise to pathological behaviors of the charge density at small radius. Here we present a full-potential implementation of the fully-relativistic KKR method to perform ab initio self-consistent calculation by directly solving the Dirac differential equations using the generalized variable phase (sine and cosine matrices) formalism Liu et al. (2016). Themore » pathology around the origin is completely eliminated by carrying out the energy integration of the single-site Green function along the real axis. Here, by using an efficient pole-searching technique to identify the zeros of the well-behaved Jost matrices, we demonstrated that this scheme is numerically stable and computationally efficient, with speed comparable to the conventional contour energy integration method, while free of the pathology problem of the charge density. As an application, this method is utilized to investigate the crystal structures of polonium and their bulk properties, which is challenging for a conventional real-energy scheme. The noble metals are also calculated, both as a test of our method and to study the relativistic effects.« less

Necroplanetology: Disrupted Planetary Material Transiting WD 1145+017

NASA Astrophysics Data System (ADS)

Manideep Duvvuri, Girish; Redfield, Seth; Veras, Dimitri

2018-06-01

The WD 1145+017 system shows irregular transit features that are consistent with the tidal disruption of differentiated asteroids with bulk densities < 4 g cm-3 and bulk masses < 1021 kg. We use the open-source N-body code REBOUND to simulate this disruption with different internal structures: varying the core volume fraction, mantle/core density ratio, and the presence/absence of a thin low-density crust. We show that these parameters have observationally distinguishable effects on the transit light curve as the asteroid is disrupted and fit the simulation-generated lightcurves to data. We find that an asteroid with a low core fraction, low mantle/density ratio, and without a crust is most consistent with the A1 feature present for multiple weeks circa April 2017. This combination of observations and simulations to study the interior structure and chemistry of exoplanetary bodies via their destruction in action is an early example of necroplanetology, a field that will hopefully grow with the discovery of other systems like WD 1145+017.

Mode conversion at density irregularities in the LAPD

NASA Astrophysics Data System (ADS)

Kersten, Kristopher; Cattell, Cynthia; van Compernolle, Bart; Gekelman, Walter; Pribyl, Pat; Vincena, Steve

2010-11-01

Mode conversion of electrostatic plasma oscillations to electromagnetic radiation is commonly observed in space plasmas as Type II and III radio bursts. Much theoretical work has addressed the phenomenon, but due to the transient nature and generation location of the bursts, experimental verification via in situ observation has proved difficult. The Large Plasma Device (LAPD) provides a reproducible plasma environment that can be tailored for the study of space plasma phenomena. A highly configurable axial magnetic field and flexible diagnostics make the device well suited for the study of plasma instabilities at density gradients. We present preliminary results of mode conversion studies performed at the LAPD. The studies employed an electron beam source configured to drive Langmuir waves towards high density plasma near the cathode discharge. Internal floating potential probes show the expected plasma oscillations ahead of the beam cathode, and external microwave antenna signals reveal a strong band of radiation near the plasma frequency that persists into the low density plasma afterglow.

Nailfold capillaroscopy in 430 patients with rheumatoid arthritis.

PubMed

Rajaei, Alireza; Dehghan, Pooneh; Amiri, Ali

2017-01-01

Microvascular changes are one of the first obvious steps in numerous inflammatory diseases such as rheumatoid arthritis (RA). Nailfold video capillaroscopy (NFC) is an easy, reliable and safe method for evaluating peripheral microangiopathy. The objective of this study was to examine nailfold microcirculation in RA patients, assess morphological and structural changes quantitatively and qualitatively, and recognize useful changes. A total of 430 patients diagnosed with RA were examined in a period of 4 years. NFC was performed on all fingers of both hands in each patient. Different parameters indicating microvascular changes were detected and analyzed; such as microvascular architecture, capillary distribution disturbances, capillary morphology, capillary density, efferent/afferent limb ratio, subpapillary venular plexus and morphological abnormalities. The obtained results were categorized into normal pattern, nonspecific morphological abnormality and scleroderma pattern. The mean age of participants was 51.03±14.54 (19-87 years) that consisted of 359 females and 71 males. Based on the findings, angiogenesis (74.7%) was the most pathological condition observed after tortuosity (99.5%). 7.2% and 20.9% of patients were categorized into normal and scleroderma pattern group, respectively. Among morphological abnormalities, angiogenesis, isolated enlarged loop, irregular enlarged loop and architectural derangement were significantly more frequent in scleroderma than normal pattern (p<0.001). NFC may play an important role in monitoring RA disease and patients' follow-up. Therefore, in our opinion it could be considered in the course and follow-up of rheumatoid arthritis.

Nailfold capillaroscopy in 430 patients with rheumatoid arthritis

PubMed Central

Rajaei, Alireza; Dehghan, Pooneh; Amiri, Ali

2017-01-01

Background: Microvascular changes are one of the first obvious steps in numerous inflammatory diseases such as rheumatoid arthritis (RA). Nailfold video capillaroscopy (NFC) is an easy, reliable and safe method for evaluating peripheral microangiopathy. The objective of this study was to examine nailfold microcirculation in RA patients, assess morphological and structural changes quantitatively and qualitatively, and recognize useful changes. Methods: A total of 430 patients diagnosed with RA were examined in a period of 4 years. NFC was performed on all fingers of both hands in each patient. Different parameters indicating microvascular changes were detected and analyzed; such as microvascular architecture, capillary distribution disturbances, capillary morphology, capillary density, efferent/afferent limb ratio, subpapillary venular plexus and morphological abnormalities. The obtained results were categorized into normal pattern, nonspecific morphological abnormality and scleroderma pattern. Results: The mean age of participants was 51.03±14.54 (19-87 years) that consisted of 359 females and 71 males. Based on the findings, angiogenesis (74.7%) was the most pathological condition observed after tortuosity (99.5%). 7.2% and 20.9% of patients were categorized into normal and scleroderma pattern group, respectively. Among morphological abnormalities, angiogenesis, isolated enlarged loop, irregular enlarged loop and architectural derangement were significantly more frequent in scleroderma than normal pattern (p<0.001). Conclusion: NFC may play an important role in monitoring RA disease and patients’ follow-up. Therefore, in our opinion it could be considered in the course and follow-up of rheumatoid arthritis. PMID:29201317

Density and Habitat Relationships of the Endemic White Mountain Fritillary (Boloria chariclea montinus) (Lepidoptera: Nymphalidae).

PubMed

McFarland, Kent P; Lloyd, John D; Hardy, Spencer P

2017-06-04

We conducted point counts in the alpine zone of the Presidential Range of the White Mountains, New Hampshire, USA, to estimate the distribution and density of the rare endemic White Mountain Fritillary ( Boloria chariclea montinus ). Incidence of occurrence and density of the endemic White Mountain Fritillary during surveys in 2012 and 2013 were greatest in the herbaceous-snowbank plant community. Densities at points in the heath-shrub-rush plant community were lower, but because this plant community is more widespread in the alpine zone, it likely supports the bulk of adult fritillaries. White Mountain Fritillary used cushion-tussock, the other alpine plant community suspected of providing habitat, only sparingly. Detectability of White Mountain Fritillaries varied as a consequence of weather conditions during the survey and among observers, suggesting that raw counts yield biased estimates of density and abundance. Point counts, commonly used to study and monitor populations of birds, were an effective means of sampling White Mountain Fritillary in the alpine environment where patches of habitat are small, irregularly shaped, and widely spaced, rendering line-transect methods inefficient and difficult to implement.

A Novel Application for the Detection of an Irregular Pulse using an iPhone 4S in Patients with Atrial Fibrillation

PubMed Central

McManus, David D.; Lee, Jinseok; Maitas, Oscar; Esa, Nada; Pidikiti, Rahul; Carlucci, Alex; Harrington, Josephine; Mick, Eric; Chon, Ki H.

2012-01-01

Background Atrial fibrillation (AF) is common and associated with adverse health outcomes. Timely detection of AF can be challenging using traditional diagnostic tools. Smartphone use is increasing and may provide an inexpensive and user-friendly means to diagnose AF. Objective To test the hypothesis that a smartphone-based application could detect an irregular pulse from AF. Methods 76 adults with persistent AF were consented for participation in our study. We obtained pulsatile time series recordings before and after cardioversion using an iPhone 4S camera. A novel smartphone application conducted real-time pulse analysis using 2 statistical methods [Root Mean Square of Successive RR Differences (RMSSD/mean); Shannon Entropy (ShE)]. We examined the sensitivity, specificity, and predictive accuracy of both algorithms using the 12-lead electrocardiogram as the gold standard. Results RMSDD/mean and ShE were higher in participants in AF compared with sinus rhythm. The 2 methods were inversely related to AF in regression models adjusting for key factors including heart rate and blood pressure (β coefficients per SD-increment in RMSDD/mean and ShE were −0.20 and −0.35; p<0.001). An algorithm combining the 2 statistical methods demonstrated excellent sensitivity (0.962), specificity (0.975), and accuracy (0.968) for beat-to-beat discrimination of an irregular pulse during AF from sinus rhythm. Conclusions In a prospectively recruited cohort of 76 participants undergoing cardioversion for AF, we found that a novel algorithm analyzing signals recorded using an iPhone 4S accurately distinguished pulse recordings during AF from sinus rhythm. Data are needed to explore the performance and acceptability of smartphone-based applications for AF detection. PMID:23220686

A novel application for the detection of an irregular pulse using an iPhone 4S in patients with atrial fibrillation.

PubMed

McManus, David D; Lee, Jinseok; Maitas, Oscar; Esa, Nada; Pidikiti, Rahul; Carlucci, Alex; Harrington, Josephine; Mick, Eric; Chon, Ki H

2013-03-01

Atrial fibrillation (AF) is common and associated with adverse health outcomes. Timely detection of AF can be challenging using traditional diagnostic tools. Smartphone use is increasing and may provide an inexpensive and user-friendly means to diagnoseAF. To test the hypothesis that a smartphone-based application could detect an irregular pulse fromAF. Seventy-six adults with persistent AF were consented for participation in our study. We obtained pulsatile time series recordings before and after cardioversion using an iPhone 4S camera. A novel smartphone application conducted real-time pulse analysis using 2 statistical methods: root mean square of successive RR difference (RMSSD/mean) and Shannon entropy (ShE). We examined the sensitivity, specificity, and predictive accuracy of both algorithms using the 12-lead electrocardiogram as the gold standard. RMSDD/mean and ShE were higher in participants in AF than in those with sinus rhythm. The 2 methods were inversely related to AF in regression models adjusting for key factors including heart rate and blood pressure (beta coefficients per SD increment in RMSDD/mean and ShE were-0.20 and-0.35; P<.001). An algorithm combining the 2 statistical methods demonstrated excellent sensitivity (0.962), specificity (0.975), and accuracy (0.968) for beat-to-beat discrimination of an irregular pulse during AF from sinus rhythm. In a prospectively recruited cohort of 76 participants undergoing cardioversion for AF, we found that a novel algorithm analyzing signals recorded using an iPhone 4S accurately distinguished pulse recordings during AF from sinus rhythm. Data are needed to explore the performance and acceptability of smartphone-based applications for AF detection. Copyright © 2013 Heart Rhythm Society. All rights reserved.

Threshold Collision Energy of the QCD Phase Diagram Tricritical Endpoint

NASA Astrophysics Data System (ADS)

Bugaev, K. A.; Emaus, R.; Sagun, V. V.; Ivanytskyi, A. I.; Bravina, L. V.; Blaschke, D. B.; Nikonov, E. G.; Taranenko, A. V.; Zabrodin, E. E.; Zinovjev, G. M.

2018-05-01

Using the most advanced formulation of the hadron resonance gas model we analyze the two sets of irregularities found at chemical freeze-out of central nuclear-nuclear collisions at the center of mass energies 3.8-4.9 GeV and 7.6-9.2 GeV. In addition to previously reported irregularities at the collision energies 4.9 and 9.2 GeV we found sharp peaks of baryonic charge density. Also we analyze the collision energy dependence of the modified Wroblewski factor and the strangeness suppression factor. Based on the thermostatic properties of the mixed phase of a 1st order phase transition and the ones of the Hagedorn mass spectrum we explain, respectively, the reason of observed chemical equilibration of strangeness at the collision energy 4.9 GeV and above 8.7 GeV. It is argued that the both sets of irregularities possibly evidence for two phase transitions, namely, the 1st order transition at lower energy range and the 2nd order transition at higher one. In combination with a recent analysis of the light nuclei number fluctuations we conclude that the center of mass collision energy range 8.8-9.2 GeV may be in the nearest vicinity of the QCD tricritical endpoint. The properties of the phase existing between two phase transitions are revealed and discussed.

Reconstruction of 3d Models from Point Clouds with Hybrid Representation

NASA Astrophysics Data System (ADS)

Hu, P.; Dong, Z.; Yuan, P.; Liang, F.; Yang, B.

2018-05-01

The three-dimensional (3D) reconstruction of urban buildings from point clouds has long been an active topic in applications related to human activities. However, due to the structures significantly differ in terms of complexity, the task of 3D reconstruction remains a challenging issue especially for the freeform surfaces. In this paper, we present a new reconstruction algorithm which allows the 3D-models of building as a combination of regular structures and irregular surfaces, where the regular structures are parameterized plane primitives and the irregular surfaces are expressed as meshes. The extraction of irregular surfaces starts with an over-segmented method for the unstructured point data, a region growing approach based the adjacent graph of super-voxels is then applied to collapse these super-voxels, and the freeform surfaces can be clustered from the voxels filtered by a thickness threshold. To achieve these regular planar primitives, the remaining voxels with a larger flatness will be further divided into multiscale super-voxels as basic units, and the final segmented planes are enriched and refined in a mutually reinforcing manner under the framework of a global energy optimization. We have implemented the proposed algorithms and mainly tested on two point clouds that differ in point density and urban characteristic, and experimental results on complex building structures illustrated the efficacy of the proposed framework.

Scintillation measurements at Bahir Dar during the high solar activity phase of solar cycle 24

NASA Astrophysics Data System (ADS)

Kriegel, Martin; Jakowski, Norbert; Berdermann, Jens; Sato, Hiroatsu; Wassaie Mersha, Mogese

2017-01-01

Small-scale ionospheric disturbances may cause severe radio scintillations of signals transmitted from global navigation satellite systems (GNSSs). Consequently, small-scale plasma irregularities may heavily degrade the performance of current GNSSs such as GPS, GLONASS or Galileo. This paper presents analysis results obtained primarily from two high-rate GNSS receiver stations designed and operated by the German Aerospace Center (DLR) in cooperation with Bahir Dar University (BDU) at 11.6° N, 37.4° E. Both receivers collect raw data sampled at up to 50 Hz, from which characteristic scintillation parameters such as the S4 index are deduced. This paper gives a first overview of the measurement set-up and the observed scintillation events over Bahir Dar in 2015. Both stations are located close to one another and aligned in an east-west, direction which allows us to estimate the zonal drift velocity and spatial dimension of equatorial ionospheric plasma irregularities. Therefore, the lag times of moving electron density irregularities and scintillation patterns are derived by applying cross-correlation analysis to high-rate measurements of the slant total electron content (sTEC) along radio links between a GPS satellite and both receivers and to the associated signal power, respectively. Finally, the drift velocity is derived from the estimated lag time, taking into account the geometric constellation of both receiving antennas and the observed GPS satellites.

Modeling the electrode-neuron interface of cochlear implants: effects of neural survival, electrode placement, and the partial tripolar configuration.

PubMed

Goldwyn, Joshua H; Bierer, Steven M; Bierer, Julie Arenberg

2010-09-01

The partial tripolar electrode configuration is a relatively novel stimulation strategy that can generate more spatially focused electric fields than the commonly used monopolar configuration. Focused stimulation strategies should improve spectral resolution in cochlear implant users, but may also be more sensitive to local irregularities in the electrode-neuron interface. In this study, we develop a practical computer model of cochlear implant stimulation that can simulate neural activation in a simplified cochlear geometry and we relate the resulting patterns of neural activity to basic psychophysical measures. We examine how two types of local irregularities in the electrode-neuron interface, variations in spiral ganglion nerve density and electrode position within the scala tympani, affect the simulated neural activation patterns and how these patterns change with electrode configuration. The model shows that higher partial tripolar fractions activate more spatially restricted populations of neurons at all current levels and require higher current levels to excite a given number of neurons. We find that threshold levels are more sensitive at high partial tripolar fractions to both types of irregularities, but these effects are not independent. In particular, at close electrode-neuron distances, activation is typically more spatially localized which leads to a greater influence of neural dead regions. Copyright (c) 2010 Elsevier B.V. All rights reserved.

Analysis of interstellar fragmentation structure based on IRAS images

NASA Technical Reports Server (NTRS)

Scalo, John M.

1989-01-01

The goal of this project was to develop new tools for the analysis of the structure of densely sampled maps of interstellar star-forming regions. A particular emphasis was on the recognition and characterization of nested hierarchical structure and fractal irregularity, and their relation to the level of star formation activity. The panoramic IRAS images provided data with the required range in spatial scale, greater than a factor of 100, and in column density, greater than a factor of 50. In order to construct a densely sampled column density map of a cloud complex which is both self-gravitating and not (yet?) stirred up much by star formation, a column density image of the Taurus region has been constructed from IRAS data. The primary drawback to using the IRAS data for this purpose is that it contains no velocity information, and the possible importance of projection effects must be kept in mind.

Comparison of Microlife BP A200 Plus and Omron M6 blood pressure monitors to detect atrial fibrillation in hypertensive patients.

PubMed

Marazzi, Giuseppe; Iellamo, Ferdinando; Volterrani, Maurizio; Lombardo, Mauro; Pelliccia, Francesco; Righi, Daniela; Grieco, Fabrizia; Cacciotti, Luca; Iaia, Luigi; Caminiti, Giuseppe; Rosano, Giuseppe

2012-01-01

Self-monitoring home blood pressure (BP) devices are currently recommended for long-term follow-up of hypertension and its management. Some of these devices are integrated with algorithms aimed at detecting atrial fibrillation (AF), which is common essential hypertension. This study was designed to compare the diagnostic accuracy of two widely diffused home BP monitoring devices in detecting AF in an unselected population of outpatients referred to a hypertension clinic because of high BP. In 503 consecutive patients the authors simultaneously compared the accuracy of the Microlife(®) BP A200 Plus (Microlife) and the OMRON(®) M6 (OMRON) home BP devices, in detecting AF. Systolic and diastolic BP as well as heart rate (HR) values detected by the two devices were not significantly different. Pulse irregularity was detected in 124 and 112 patients with the OMRON M6 and Microlife BP A200 Plus devices, respectively. Simultaneous electrocardiogram (ECG) recording revealed that pulse irregularity was due to AF in 101 patients. Pulse irregularity detected by the OMRON M6 device corresponded to AF in 101, to supraventricular premature beats in 18, and to frequent premature ventricular beat in five patients, respectively. Pulse irregularity detected by the Microlife BP A200 Plus device corresponded to AF in 93, to supraventricular premature beats in 14, and to ventricular premature beats in five patients. The sensitivity for detecting AF was 100%, the specificity was 92%, and diagnostic accuracy 95% for the OMRON M6 and 100%, 92%, and 95 for the Microlife BP A200 Plus, respectively. AF was newly diagnosed by ECG recordings in 47 patients, and was detected in all patients by the OMRON device, and in 42 patients by the Microlife device. These results indicate that OMRON M6 is more accurate than Microlife BP A200 Plus in detecting AF in patients with essential hypertension. Widespread use of these devices in hypertensive patients could be of clinical benefit for the early diagnosis and treatment of this arrhythmia and related consequences.

Accuracy of methods for detecting an irregular pulse and suspected atrial fibrillation: A systematic review and meta-analysis

PubMed Central

Coleman, Tim; Lewis, Sarah; Heneghan, Carl; Jones, Matthew

2015-01-01

Background Pulse palpation has been recommended as the first step of screening to detect atrial fibrillation. We aimed to determine and compare the accuracy of different methods for detecting pulse irregularities caused by atrial fibrillation. Methods We systematically searched MEDLINE, EMBASE, CINAHL and LILACS until 16 March 2015. Two reviewers identified eligible studies, extracted data and appraised quality using the QUADAS-2 instrument. Meta-analysis, using the bivariate hierarchical random effects method, determined average operating points for sensitivities, specificities, positive and negative likelihood ratios (PLR, NLR); we constructed summary receiver operating characteristic plots. Results Twenty-one studies investigated 39 interventions (n = 15,129 pulse assessments) for detecting atrial fibrillation. Compared to 12-lead electrocardiography (ECG) diagnosed atrial fibrillation, blood pressure monitors (BPMs; seven interventions) and non-12-lead ECGs (20 interventions) had the greatest accuracy for detecting pulse irregularities attributable to atrial fibrillation (BPM: sensitivity 0.98 (95% confidence interval (CI) 0.92–1.00), specificity 0.92 (95% CI 0.88–0.95), PLR 12.1 (95% CI 8.2–17.8) and NLR 0.02 (95% CI 0.00–0.09); non-12-lead ECG: sensitivity 0.91 (95% CI 0.86–0.94), specificity 0.95 (95% CI 0.92–0.97), PLR 20.1 (95% CI 12–33.7), NLR 0.09 (95% CI 0.06–0.14)). There were similar findings for smartphone applications (six interventions) although these studies were small in size. The sensitivity and specificity of pulse palpation (six interventions) were 0.92 (95% CI 0.85–0.96) and 0.82 (95% CI 0.76–0.88), respectively (PLR 5.2 (95% CI 3.8–7.2), NLR 0.1 (95% CI 0.05–0.18)). Conclusions BPMs and non-12-lead ECG were most accurate for detecting pulse irregularities caused by atrial fibrillation; other technologies may therefore be pragmatic alternatives to pulse palpation for the first step of atrial fibrillation screening. PMID:26464292

Tuning Neural Phase Entrainment to Speech.

PubMed

Falk, Simone; Lanzilotti, Cosima; Schön, Daniele

2017-08-01

Musical rhythm positively impacts on subsequent speech processing. However, the neural mechanisms underlying this phenomenon are so far unclear. We investigated whether carryover effects from a preceding musical cue to a speech stimulus result from a continuation of neural phase entrainment to periodicities that are present in both music and speech. Participants listened and memorized French metrical sentences that contained (quasi-)periodic recurrences of accents and syllables. Speech stimuli were preceded by a rhythmically regular or irregular musical cue. Our results show that the presence of a regular cue modulates neural response as estimated by EEG power spectral density, intertrial coherence, and source analyses at critical frequencies during speech processing compared with the irregular condition. Importantly, intertrial coherences for regular cues were indicative of the participants' success in memorizing the subsequent speech stimuli. These findings underscore the highly adaptive nature of neural phase entrainment across fundamentally different auditory stimuli. They also support current models of neural phase entrainment as a tool of predictive timing and attentional selection across cognitive domains.

The Secular Evolution Of Disc Galaxies And The Origin Of Exponential And Double Exponential Surface Density Profiles

NASA Astrophysics Data System (ADS)

Elmegreen, Bruce G.

2016-10-01

Exponential radial profiles are ubiquitous in spiral and dwarf Irregular galaxies, but the origin of this structural form is not understood. This talk will review the observations of exponential and double exponential disks, considering both the light and the mass profiles, and the contributions from stars and gas. Several theories for this structure will also be reviewed, including primordial collapse, bar and spiral torques, clump torques, galaxy interactions, disk viscosity and other internal processes of angular momentum exchange, and stellar scattering off of clumpy structure. The only process currently known that can account for this structure in the most theoretically difficult case is stellar scattering off disks clumps. Stellar orbit models suggest that such scattering can produce exponentials even in isolated dwarf irregulars that have no bars or spirals, little shear or viscosity, and profiles that go out too far for the classical Mestel case of primordial collapse with specific angular momentum conservation.

Study of midlatitude ionospheric irregularities and E- and F-region coupling based on rocket and radar observations from Japan

NASA Astrophysics Data System (ADS)

Yamamoto, M.

2015-12-01

We have been studying ionspheric irregularities in mid-latitude region by using radars, sounding rockets, etc. The mid-latitude ionosphere was considered much stable than those in the equatorial or polar region in the past, but our studies for years have revealed that there are much active variabilities. We found variety of wave-like structures that are specific in the mid-latitudes. One of the phenomena is quasi-periodic echoes (QP echoes) first observed by the MU radar that reflects horizontal plasma-density structures associated to sporadic-E layers. Another phenomenon is medium-scale traveling ionospheric disturbance (MSTID) in the F-region. In the generation mechanism we think that Ionospheric E- and F-region coupling process is important. In this presentation, we will discuss nature of mid-latitude ionosphere based on our observations; the MU radar, sounding rocket campaigns of SEEK-1/2, and recent MSTID rocket experiment from JAXA Uchinoura Space Center in July 2013.

A Study of Two Dwarf Irregular Galaxies with Asymmetrical Star Formation Distributions

NASA Astrophysics Data System (ADS)

Hunter, Deidre A.; Gallardo, Samavarti; Zhang, Hong-Xin; Adamo, Angela; Cook, David O.; Oh, Se-Heon; Elmegreen, Bruce G.; Kim, Hwihyun; Kahre, Lauren; Ubeda, Leonardo; Bright, Stacey N.; Ryon, Jenna E.; Fumagalli, Michele; Sacchi, Elena; Kennicutt, R. C.; Tosi, Monica; Dale, Daniel A.; Cignoni, Michele; Messa, Matteo; Grebel, Eva K.; Gouliermis, Dimitrios A.; Sabbi, Elena; Grasha, Kathryn; Gallagher, John S., III; Calzetti, Daniela; Lee, Janice C.

2018-03-01

Two dwarf irregular galaxies, DDO 187 and NGC 3738, exhibit a striking pattern of star formation: intense star formation is taking place in a large region occupying roughly half of the inner part of the optical galaxy. We use data on the H I distribution and kinematics and stellar images and colors to examine the properties of the environment in the high star formation rate (HSF) halves of the galaxies in comparison with the low star formation rate halves. We find that the pressure and gas density are higher on the HSF sides by 30%–70%. In addition we find in both galaxies that the H I velocity fields exhibit significant deviations from ordered rotation and there are large regions of high-velocity dispersion and multiple velocity components in the gas beyond the inner regions of the galaxies. The conditions in the HSF regions are likely the result of large-scale external processes affecting the internal environment of the galaxies and enabling the current star formation there.

Farley-Buneman Instability in the Solar Chromosphere

NASA Astrophysics Data System (ADS)

Gogoberidze, G.; Voitenko, Y.; Poedts, S.; Goossens, M.

2009-11-01

The Farley-Buneman instability (FBI) is studied in the partially ionized plasma of the solar chromosphere taking into account the finite magnetization of the ions and Coulomb collisions. We obtain the threshold value for the relative velocity between ions and electrons necessary for the instability to develop. It is shown that Coulomb collisions play a destabilizing role in the sense that they enable the instability even in the regions where the ion magnetization is larger than unity. By applying these results to chromospheric conditions, we show that the FBI cannot be responsible for the quasi-steady heating of the solar chromosphere. However, we do not exclude the instability development locally in the presence of strong cross-field currents and/or strong small-scale magnetic fields. In such cases, FBI should produce locally small-scale, ~0.1-3 m, density irregularities in the solar chromosphere. These irregularities can cause scintillations of radio waves with similar wave lengths and provide a tool for remote chromospheric sensing.

FARLEY-BUNEMAN INSTABILITY IN THE SOLAR CHROMOSPHERE

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gogoberidze, G.; Voitenko, Y.; Poedts, S.

2009-11-20

The Farley-Buneman instability (FBI) is studied in the partially ionized plasma of the solar chromosphere taking into account the finite magnetization of the ions and Coulomb collisions. We obtain the threshold value for the relative velocity between ions and electrons necessary for the instability to develop. It is shown that Coulomb collisions play a destabilizing role in the sense that they enable the instability even in the regions where the ion magnetization is larger than unity. By applying these results to chromospheric conditions, we show that the FBI cannot be responsible for the quasi-steady heating of the solar chromosphere. However,more » we do not exclude the instability development locally in the presence of strong cross-field currents and/or strong small-scale magnetic fields. In such cases, FBI should produce locally small-scale, approx0.1-3 m, density irregularities in the solar chromosphere. These irregularities can cause scintillations of radio waves with similar wave lengths and provide a tool for remote chromospheric sensing.« less

The LWS Geospace Storm Investigations Exploring the Extremes of Space Weather

NASA Technical Reports Server (NTRS)

2002-01-01

The Geospace mission of the Living With a Star program is a family of investigations focusing on the compelling science questions that advance our ability to specify, understand, and predict the societal impact of solar variance. Two key areas have been identified as combining both importance to society and potential for scientific progress: 1) characterization and understanding of the acceleration, global distribution, and variability of energetic electrons and ions in the inner magnetosphere, and 2) characterization and understanding of the ionosphere and irregularities that affect communications, navigation and radar systems. Under these broad categories specific science questions have emerged as the priority science objectives for the first Geospace Investigations: How and why do relativistic electrons in the outer zone and slot region vary during geomagnetic storms? How does the long- and short-term variability of the Sun affect the global-scale behavior of the ionospheric electron density and irregularities, especially during magnetic storms and at mid-latitudes? The first Geospace mission will attempt to answer these questions.

Sporadic E ionization layers observed with radar imaging and ionospheric modification

NASA Astrophysics Data System (ADS)

Hysell, D. L.; Munk, J.; McCarrick, M.

2014-10-01

Sporadic E ionization layers have been observed in the daytime subauroral ionospheric E layer by a 30 MHz radar in Alaska. The radar detects coherent backscatter from meter-scale field-aligned plasma density irregularities. The irregularities were generated by ionospheric modification—by the emission of strong HF electromagnetic waves directly beneath the layers—making the layers visible to the radar. Aperture-synthesis methods are used to generate imagery of the layers from the radar data. The layers are patchy, with patches organized along fronts spaced by tens of kilometers and propagating slowly toward the southwest. Similar, naturally occurring layers are commonly observed at middle latitudes at night in the absence of ionospheric modification. That the patchy layers can be found at high magnetic latitudes during the day argues that they are most likely produced through the interaction of the ionospheric layer with neutral atmospheric waves and instabilities. Attenuation of the radar echoes when the HF emission frequency exceeded the third harmonic of the electron gyrofrequency was observed and is discussed.

A Young Man with Non-alcoholic Steatohepatitis and Serum Anti-mitochondrial Antibody Positivity: A Case Report.

PubMed

Seike, Takuya; Komura, Takuya; Shimizu, Yoshiaki; Omura, Hitoshi; Kumai, Tatsuo; Kagaya, Takashi; Ohta, Hajime; Kawashima, Atsuhiro; Harada, Kenichi; Kaneko, Shuichi; Unoura, Masashi

2018-06-06

A 37-year-old obese man who was a social drinker was admitted to our hospital to undergo a detailed examination for liver injury with anti-mitochondrial antibody positivity. Abdominal ultrasonography revealed moderate fatty liver. A histological analysis showed steatosis of approximately 30% of the hepatocytes, focal necrosis, a few ballooning hepatocytes and lobular inflammation suggestive of steatohepatitis, epithelioid granuloma and irregularity of the sequence of the bile duct epithelium accompanied by lymphocyte infiltration suggestive of chronic cholangitis. He was diagnosed with non-alcoholic steatohepatitis complicated with primary biliary cholangitis. His liver injury was improved by weight loss and high-dose ursodeoxycholic acid treatment.

A Very Rare Cause of Anal Atresia: Currarino Syndrome

PubMed Central

Buyukbese Sarsu, Sevgi; Parmaksiz, Mehmet Ergun; Cabalar, Esra; Karapur, Ali; Kaya, Cihat

2016-01-01

Currarino syndrome (triad) is an extremely rare condition characterized by presacral mass, anorectal malformation, and sacral bone deformation. The complete form of this syndrome displays all three irregularities. Herein, we report a male case who was admitted to our hospital with symptoms of urinary system infection and persistent constipation 2 years after colostomy operation performed with the indication of rectovestibular fistula and anal atresia, diagnosed as Currarino syndrome based on imaging modalities. In a patient who was admitted because of the presence of anal atresia, in order to preclude potential complications, probable concomitancy of this syndrome should not be forgotten. Early diagnosis is important for the prevention of meningitis, urinary tract infections, and malignant change. PMID:27081429

MRI of injury to the lateral collateral ligamentous complex of the ankle.

PubMed

Cardone, B W; Erickson, S J; Den Hartog, B D; Carrera, G F

1993-01-01

We retrospectively evaluated the lateral collateral ligamentous complex of 43 patients who had complained of ankle pain following ankle sprain. The MR signs of ligamentous abnormality included discontinuity or absence, increased signal within the ligament, and ligamentous irregularity or waviness with normal thickness and signal intensity. Using these criteria, 30 anterior talofibular, 20 calcaneofibular, and no posterior talofibular ligament injuries were diagnosed. Compared with surgery (nine patients), MRI demonstrated six of seven anterior talofibular ligament injuries and six of six calcaneofibular ligament injuries. Magnetic resonance showed ligamentous abnormalities in 12 of 23 cases with normal stress radiography. Magnetic resonance imaging provides useful information for the evaluation of patients presenting with chronic pain after ankle sprain.

Rapid recovery from congestive heart failure following successful radiofrequency catheter ablation in a patient with late onset of Wolff-Parkinson-White syndrome.

PubMed

Yodogawa, Kenji; Ono, Norihiko; Seino, Yoshihiko

2012-01-01

A 56-year-old man was admitted because of palpitations and dyspnea. A 12-lead electrocardiogram showed irregular wide QRS complex tachycardia with a slur at the initial portion of the QRS complex. He had preexisting long-standing persistent atrial fibrillation, but early excitation syndrome had never been noted. Chest X-ray showed heart enlargement and pulmonary congestion. He was diagnosed with late onset of Wolff-Parkinson-White syndrome, and congestive heart failure was probably caused by rapid ventricular response of atrial fibrillation through the accessory pathway. Emergency catheter ablation for the accessory pathway was undertaken, and heart failure was dramatically improved.

Curiosity Drill After Drilling at Telegraph Peak

NASA Image and Video Library

2015-03-06

This view from the Mast Camera (Mastcam) on NASA's Curiosity Mars rover shows the rover's drill just after finishing a drilling operation at a target rock called "Telegraph Peak" on Feb. 24, 2015, the 908th Martian day, or sol, of the rover's work on Mars. Three sols later, a fault-protection action by the rover halted a process of transferring sample powder that was collected during this drilling. The image is in raw color, as recorded directly by the camera, and has not been white-balanced. The fault-protection event, triggered by an irregularity in electrical current, led to engineering tests in subsequent days to diagnose the underlying cause. http://photojournal.jpl.nasa.gov/catalog/PIA19145

Observations of peculiar sporadic sodium structures and their relation with wind variations

NASA Astrophysics Data System (ADS)

Sridharan, S.; Prasanth, P. Vishnu; Kumar, Y. Bhavani; Ramkumar, Geetha; Sathishkumar, S.; Raghunath, K.

2009-04-01

Resonance lidar observations of sodium density in the upper mesosphere region over Gadanki (13.5°N, 79.2°E) rarely show complex structures with rapid enhancements of sodium density, completely different from normal sporadic sodium structures. The hourly averaged meteor radar zonal winds over Trivandrum (8.5°N, 76.5°E) show an eastward shear with altitude during the nights, when these events are formed. As suggested by Kane et al. [2001. Joint observations of sodium enhancements and field-aligned ionospheric irregularities. Geophysical Research Letters 28, 1375-1378], our observations show that the complex structures may be formed due to Kelvin-Helmholtz instability, which can occur in the region of strong wind shear.

Detection of Atrial Fibrillation Using Artifical Neural Network with Power Spectrum Density of RR Interval of Electrocardiogram

NASA Astrophysics Data System (ADS)

Afdala, Adfal; Nuryani, Nuryani; Satrio Nugroho, Anto

2017-01-01

Atrial fibrillation (AF) is a disorder of the heart with fairly high mortality in adults. AF is a common heart arrythmia which is characterized by a missing or irregular contraction of atria. Therefore, finding a method to detect atrial fibrillation is necessary. In this article a system to detect atrial fibrillation has been proposed. Detection system utilized backpropagation artifical neural network. Data input in this method includes power spectrum density of R-peaks interval of electrocardiogram which is selected by wrapping method. This research uses parameter learning rate, momentum, epoch and hidden layer. System produces good performance with accuracy, sensitivity, and specificity of 83.55%, 86.72 % and 81.47 %, respectively.

Stromal haze, myofibroblasts, and surface irregularity after PRK.

PubMed

Netto, Marcelo V; Mohan, Rajiv R; Sinha, Sunilima; Sharma, Ajay; Dupps, William; Wilson, Steven E

2006-05-01

The aim of this study was to investigate the relationship between the level of stromal surface irregularity after photorefractive keratectomy (PRK) and myofibroblast generation along with the development of corneal haze. Variable levels of stromal surface irregularity were generated in rabbit corneas by positioning a fine mesh screen in the path of excimer laser during ablation for a variable percentage of the terminal pulses of the treatment for myopia that does not otherwise generate significant opacity. Ninety-six rabbits were divided into eight groups: [see table in text]. Slit lamp analysis and haze grading were performed in all groups. Rabbits were sacrificed at 4 hr or 4 weeks after surgery and histochemical analysis was performed on corneas for apoptosis (TUNEL assay), myofibroblast marker alpha-smooth muscle actin (SMA), and integrin alpha4 to delineate the epithelial basement membrane. Slit-lamp grading revealed severe haze formation in corneas in groups IV and VI, with significantly less haze in groups II, III, and VII and insignificant haze compared with the unwounded control in groups I and V. Analysis of SMA staining at 4 weeks after surgery, the approximate peak of haze formation in rabbits, revealed low myofibroblast formation in group I (1.2+/-0.2 cells/400x field) and group V (1.8+/-0.4), with significantly more in groups II (3.5+/-1.8), III (6.8+/-1.6), VII (7.9+/-3.8), IV (12.4+/-4.2) and VI (14.6+/-5.1). The screened groups were significantly different from each other (p < 0.05), with myofibroblast generation increasing with higher surface irregularity in the -4.5 diopter PRK groups. The -9.0 diopter PRK group VI had significantly more myofibroblast generation than the -9.0 diopter PRK with PTK-smoothing group VII (p < 0.01). Areas of basement membrane disruption were demonstrated by staining corneas for integrin alpha4 and were prominent in corneas with grade I or higher haze. SMA-positive myofibroblasts tended to be present sub-adjacent to basement membrane defects. Late apoptosis was detected at 1 month after surgery within clusters of myofibroblasts in the sub-epithelial stroma. In conclusion, these results demonstrated a relationship between the level of corneal haze formation after PRK and the level of stromal surface irregularity. PTK-smoothing with methylcellulose was an effective method to reduce stromal surface irregularity and decreased both haze and associated myofibroblast density. We hypothesize that stromal surface irregularity after PRK for high myopia results in defective basement membrane regeneration and increased epithelium-derived TGFbeta signalling to the stroma that increases myofibroblast generation. Late apoptosis appears to have a role in the disappearance of myofibroblasts and haze over time.

Molecular clouds in galaxies with different Z - Fragmentation of diffuse clouds driven by opacity

NASA Technical Reports Server (NTRS)

Franco, Jose; Cox, Donald P.

1986-01-01

Molecular clouds are formed from diffuse interstellar clouds when the external ultraviolet radiation field is prevented from penetrating into the cloud. The opacity is provided mainly by dust grains and the required column density to the cloud center is larger than about 5 x 10 to the 20th (solar Z/Z)/sq cm. This high-opacity criterion could have a significant impact on the radial trends observed in spiral galaxies, and on the distinctions between spiral and dwarf irregular galaxies.

The microwave background: Its smoothness and frequency distribution as an astrophysical product

NASA Astrophysics Data System (ADS)

Hoyle, Fred; Wickramasinghe, N. C.; Burbidge, Geoffrey

1990-12-01

The use of astrophysical sources in providing an understanding of the total energy density of the background is reviewed. The need of a thermalizing agent is stressed. The nearer such an agent comes to establishing thermodynamic equilibrium, the smoother the background becomes. This is shown to be true despite irregularities in the distribution of the thermalizer. The ejection of iron whiskers from galaxies and the ways in which such whiskers could affect the microwave background are discussed.

Study of the activities of MSTIDs, FAIs, and scintillations in middle latitudes

NASA Astrophysics Data System (ADS)

Oh, S. J.; Kil, H.; Kwak, Y. S.; Tae-yong, Y.

2017-12-01

We investigate the role of medium-scale traveling ionospheric disturbances (MSTIDs) in the creation of field-aligned irregularities (FAIs) and scintillations in middle latitudes. The occurrences of MSTIDs, FAIs, and scintillations are monitored using the total electron content perturbation maps over Japan, observations of VHF radar at Daejeon in South Korea, and observations of scintillation monitors over South Korea, respectively. The observations of the electron density by Swarm satellites are used for the investigation of the conjugate property in MSTIDs and FAIs.

Hypothalamic amenorrhea in young women with underlying polycystic ovary syndrome.

PubMed

Sum, Melissa; Warren, Michelle P

2009-12-01

The purpose of this study was to compare the hormonal/clinical profiles and markers of bone health of women with hypothalamic amenorrhea (HA) to women with suspected HA and underlying polycystic ovary syndrome (PCOS). The results indicate that compared to women with HA, women with HA and underlying PCOS exhibit higher body mass index (BMI), bone mineral densities, and incidence of hyperandrogenism, that they may exhibit increased hyperandrogenism and irregular menses with weight gain, and that they remain at similar risk for osteopenia and osteoporosis.

An International Consortium Update: Pathophysiology, Diagnosis, and Treatment of Polycystic Ovarian Syndrome in Adolescence.

PubMed

Ibáñez, Lourdes; Oberfield, Sharon E; Witchel, Selma; Auchus, Richard J; Chang, R Jeffrey; Codner, Ethel; Dabadghao, Preeti; Darendeliler, Feyza; Elbarbary, Nancy Samir; Gambineri, Alessandra; Garcia Rudaz, Cecilia; Hoeger, Kathleen M; López-Bermejo, Abel; Ong, Ken; Peña, Alexia S; Reinehr, Thomas; Santoro, Nicola; Tena-Sempere, Manuel; Tao, Rachel; Yildiz, Bulent O; Alkhayyat, Haya; Deeb, Asma; Joel, Dipesalema; Horikawa, Reiko; de Zegher, Francis; Lee, Peter A

2017-01-01

This paper represents an international collaboration of paediatric endocrine and other societies (listed in the Appendix) under the International Consortium of Paediatric Endocrinology (ICPE) aiming to improve worldwide care of adolescent girls with polycystic ovary syndrome (PCOS)1. The manuscript examines pathophysiology and guidelines for the diagnosis and management of PCOS during adolescence. The complex pathophysiology of PCOS involves the interaction of genetic and epigenetic changes, primary ovarian abnormalities, neuroendocrine alterations, and endocrine and metabolic modifiers such as anti-Müllerian hormone, hyperinsulinemia, insulin resistance, adiposity, and adiponectin levels. Appropriate diagnosis of adolescent PCOS should include adequate and careful evaluation of symptoms, such as hirsutism, severe acne, and menstrual irregularities 2 years beyond menarche, and elevated androgen levels. Polycystic ovarian morphology on ultrasound without hyperandrogenism or menstrual irregularities should not be used to diagnose adolescent PCOS. Hyperinsulinemia, insulin resistance, and obesity may be present in adolescents with PCOS, but are not considered to be diagnostic criteria. Treatment of adolescent PCOS should include lifestyle intervention, local therapies, and medications. Insulin sensitizers like metformin and oral contraceptive pills provide short-term benefits on PCOS symptoms. There are limited data on anti-androgens and combined therapies showing additive/synergistic actions for adolescents. Reproductive aspects and transition should be taken into account when managing adolescents. © 2017 S. Karger AG, Basel.

Late onset neonatal anaemia due to maternal anti-Kp(b) induced haemolytic disease of the newborn.

PubMed

Elhence, Priti; Sachan, Deepti; Verma, Anupam; Kumar, Archana; Chaudhary, Rajendra

2012-12-01

Alloanti-Kp(b) is a rare, clinically significant antibody against high frequency red cell antigen Kp(b) of Kell blood group system. We report here a case of Haemolytic disease of newborn (HDN) due to anti-Kp(b), which manifested as severe anaemia at the age of 1 month. To diagnose and successfully manage anti-Kp(b) induced HDN. Direct antiglobulin test (DAT), antigen typing, irregular antibody screening and identification were done by polyspecific LISS Coombs Gel card and standard methods. At presentation the neonate had severe anemia with reticulocytopenia. Blood group was B, Rh D positive and DAT was 2+. Anti-Kp(b) was detected in mother's serum. Due to unavailability of Kp(b) negative red cells and incompatible blood group of mother (A(1)B Rh D positive) infant was transfused group B Rh D, Kp(b) positive PRBCs under steroid cover. He was symptom free at 4 months of age and DAT became negative at 6 months. Anti-Kp(b) is capable of causing severe late HDN. Infants born to irregular antibody positive mothers should be investigated and closely monitored for several weeks after birth for immune HDN even if asymptomatic at birth. Copyright © 2012 Elsevier Ltd. All rights reserved.

The Wire-Grasping Method as a New Technique for Forceps Biopsy of Biliary Strictures: A Prospective Randomized Controlled Study of Effectiveness.

PubMed

Yamashita, Yasunobu; Ueda, Kazuki; Kawaji, Yuki; Tamura, Takashi; Itonaga, Masahiro; Yoshida, Takeichi; Maeda, Hiroki; Magari, Hirohito; Maekita, Takao; Iguchi, Mikitaka; Tamai, Hideyuki; Ichinose, Masao; Kato, Jun

2016-07-15

Transpapillary forceps biopsy is an effective diagnostic technique in patients with biliary stricture. This prospective study aimed to determine the usefulness of the wire-grasping method as a new technique for forceps biopsy. Consecutive patients with biliary stricture or irregularities of the bile duct wall were randomly allocated to either the direct or wire-grasping method group. In the wiregrasping method, forceps in the duodenum grasps a guidewire placed into the bile duct beforehand, and then, the forceps are pushed through the papilla without endoscopic sphincterotomy. In the direct method, forceps are directly pushed into the bile duct alongside a guide-wire. The primary endpoint was the success rate of obtaining specimens suitable for adequate pathological examination. In total, 32 patients were enrolled, and 28 (14 in each group) were eligible for analysis. The success rate was significantly higher using the wire-grasping method than the direct method (100% vs 50%, p=0.016). Sensitivity and accuracy for the diagnosis of cancer were comparable in patients with the successful procurement of biopsy specimens between the two methods (91% vs 83% and 93% vs 86%, respectively). The wire-grasping method is useful for diagnosing patients with biliary stricture or irregularities of the bile duct wall.

Self-reported well-being score modelling and prediction: Proof-of-concept of an approach based on linear dynamic systems.

PubMed

Xinyang Li; Poli, Riccardo; Valenza, Gaetano; Scilingo, Enzo Pasquale; Citi, Luca

2017-07-01

Assessment and recognition of perceived well-being has wide applications in the development of assistive healthcare systems for people with physical and mental disorders. In practical data collection, these systems need to be less intrusive, and respect users' autonomy and willingness as much as possible. As a result, self-reported data are not necessarily available at all times. Conventional classifiers, which usually require feature vectors of a prefixed dimension, are not well suited for this problem. To address the issue of non-uniformly sampled measurements, in this study we propose a method for the modelling and prediction of self-reported well-being scores based on a linear dynamic system. Within the model, we formulate different features as observations, making predictions even in the presence of inconsistent and irregular data. We evaluate the proposed method with synthetic data, as well as real data from two patients diagnosed with cancer. In the latter, self-reported scores from three well-being-related scales were collected over a period of approximately 60 days. Prompted each day, the patients had the choice whether to respond or not. Results show that the proposed model is able to track and predict the patients' perceived well-being dynamics despite the irregularly sampled data.

Automated diagnosis of autism: in search of a mathematical marker.

PubMed

Bhat, Shreya; Acharya, U Rajendra; Adeli, Hojjat; Bairy, G Muralidhar; Adeli, Amir

2014-01-01

Autism is a type of neurodevelopmental disorder affecting the memory, behavior, emotion, learning ability, and communication of an individual. An early detection of the abnormality, due to irregular processing in the brain, can be achieved using electroencephalograms (EEG). The variations in the EEG signals cannot be deciphered by mere visual inspection. Computer-aided diagnostic tools can be used to recognize the subtle and invisible information present in the irregular EEG pattern and diagnose autism. This paper presents a state-of-the-art review of automated EEG-based diagnosis of autism. Various time domain, frequency domain, time-frequency domain, and nonlinear dynamics for the analysis of autistic EEG signals are described briefly. A focus of the review is the use of nonlinear dynamics and chaos theory to discover the mathematical biomarkers for the diagnosis of the autism analogous to biological markers. A combination of the time-frequency and nonlinear dynamic analysis is the most effective approach to characterize the nonstationary and chaotic physiological signals for the automated EEG-based diagnosis of autism spectrum disorder (ASD). The features extracted using these nonlinear methods can be used as mathematical markers to detect the early stage of autism and aid the clinicians in their diagnosis. This will expedite the administration of appropriate therapies to treat the disorder.

Breast Density and Benign Breast Disease: Risk Assessment to Identify Women at High Risk of Breast Cancer.

PubMed

Tice, Jeffrey A; Miglioretti, Diana L; Li, Chin-Shang; Vachon, Celine M; Gard, Charlotte C; Kerlikowske, Karla

2015-10-01

Women with proliferative breast lesions are candidates for primary prevention, but few risk models incorporate benign findings to assess breast cancer risk. We incorporated benign breast disease (BBD) diagnoses into the Breast Cancer Surveillance Consortium (BCSC) risk model, the only breast cancer risk assessment tool that uses breast density. We developed and validated a competing-risk model using 2000 to 2010 SEER data for breast cancer incidence and 2010 vital statistics to adjust for the competing risk of death. We used Cox proportional hazards regression to estimate the relative hazards for age, race/ethnicity, family history of breast cancer, history of breast biopsy, BBD diagnoses, and breast density in the BCSC. We included 1,135,977 women age 35 to 74 years undergoing mammography with no history of breast cancer; 17% of the women had a prior breast biopsy. During a mean follow-up of 6.9 years, 17,908 women were diagnosed with invasive breast cancer. The BCSC BBD model slightly overpredicted risk (expected-to-observed ratio, 1.04; 95% CI, 1.03 to 1.06) and had modest discriminatory accuracy (area under the receiver operator characteristic curve, 0.665). Among women with proliferative findings, adding BBD to the model increased the proportion of women with an estimated 5-year risk of 3% or higher from 9.3% to 27.8% (P<.001). The BCSC BBD model accurately estimates women's risk for breast cancer using breast density and BBD diagnoses. Greater numbers of high-risk women eligible for primary prevention after BBD diagnosis are identified using the BCSC BBD model. © 2015 by American Society of Clinical Oncology.

Breast Density and Benign Breast Disease: Risk Assessment to Identify Women at High Risk of Breast Cancer

PubMed Central

Tice, Jeffrey A.; Miglioretti, Diana L.; Li, Chin-Shang; Vachon, Celine M.; Gard, Charlotte C.; Kerlikowske, Karla

2015-01-01

Purpose Women with proliferative breast lesions are candidates for primary prevention, but few risk models incorporate benign findings to assess breast cancer risk. We incorporated benign breast disease (BBD) diagnoses into the Breast Cancer Surveillance Consortium (BCSC) risk model, the only breast cancer risk assessment tool that uses breast density. Methods We developed and validated a competing-risk model using 2000 to 2010 SEER data for breast cancer incidence and 2010 vital statistics to adjust for the competing risk of death. We used Cox proportional hazards regression to estimate the relative hazards for age, race/ethnicity, family history of breast cancer, history of breast biopsy, BBD diagnoses, and breast density in the BCSC. Results We included 1,135,977 women age 35 to 74 years undergoing mammography with no history of breast cancer; 17% of the women had a prior breast biopsy. During a mean follow-up of 6.9 years, 17,908 women were diagnosed with invasive breast cancer. The BCSC BBD model slightly overpredicted risk (expected-to-observed ratio, 1.04; 95% CI, 1.03 to 1.06) and had modest discriminatory accuracy (area under the receiver operator characteristic curve, 0.665). Among women with proliferative findings, adding BBD to the model increased the proportion of women with an estimated 5-year risk of 3% or higher from 9.3% to 27.8% (P < .001). Conclusion The BCSC BBD model accurately estimates women's risk for breast cancer using breast density and BBD diagnoses. Greater numbers of high-risk women eligible for primary prevention after BBD diagnosis are identified using the BCSC BBD model. PMID:26282663

Insertable cardiac monitors in the diagnosis of syncope and the detection of atrial fibrillation: A systematic review and meta-analysis.

PubMed

Burkowitz, Jörg; Merzenich, Carina; Grassme, Kathrin; Brüggenjürgen, Bernd

2016-08-01

Insertable or implantable cardiac monitors (ICMs) continuously monitor the heart rhythm and record irregularities over 3 years, enabling the diagnosis of infrequent rhythm abnormalities associated with syncope and stroke. The enhanced recognition capabilities of recent ICM models are able to accurately detect atrial fibrillation (AF) and have led to new applications of ICMs for the detection and monitoring of AF. Based on a systematic literature search, two indications were identified for ICMs for which considerable evidence, including randomized studies, exists: diagnosing the underlying cardiac cause of unexplained recurrent syncope and detecting AF in patients after cryptogenic stroke (CS). Three randomized controlled trials (RCTs) were identified that compared the effectiveness of ICMs in diagnosing patients with unexplained syncope (n = 556) to standard of care. A meta-analysis was conducted in order to generate an overall effect size and confidence interval of the diagnostic yield of ICMs versus conventional monitoring. In the indication CS, one RCT and five observational studies were included in order to assess the performance of ICMs in diagnosing patients with AF (n = 1129). Based on these studies, there is strong evidence that ICMs provide a higher diagnostic yield for detecting arrhythmias in patients with unexplained syncope and for detection of AF in patients after CS compared to conventional monitoring. Prolonged monitoring with ICMs is an effective tool for diagnosing the underlying cardiac cause of unexplained syncope and for detecting AF in patients with CS. In all RCTs, ICMs have a superior diagnostic yield compared to conventional monitoring. © The European Society of Cardiology 2016.

Diagnosing laser-preheated magnetized plasmas relevant to magnetized liner inertial fusion

DOE PAGES

Harvey-Thompson, Adam James; Sefkow, Adam B.; Nagayama, Taisuke N.; ...

2015-12-22

In this paper, we present a platform on the OMEGA EP Laser Facility that creates and diagnoses the conditions present during the preheat stage of the MAGnetized Liner Inertial Fusion (MagLIF) concept. Experiments were conducted using 9 kJ of 3ω (355 nm) light to heat an underdense deuterium gas (electron density: 2.5 × 10 20 cm -3 = 0.025 of critical density) magnetized with a 10 T axial field. Results show that the deuterium plasma reached a peak electron temperature of 670 ± 140 eV, diagnosed using streaked spectroscopy of an argon dopant. The results demonstrate that plasmas relevant tomore » the preheat stage of MagLIF can be produced at multiple laser facilities, thereby enabling more rapid progress in understanding magnetized preheat. Results are compared with magneto-radiation-hydrodynamics simulations, and plans for future experiments are described.« less

An assessment of the application of in situ ion-density data from DMSP to modeling of transionospheric scintillation

NASA Astrophysics Data System (ADS)

Secan, James A.; Reinleitner, Lee A.; Bussey, Robert M.

1990-03-01

Modern military communication, navigation, and surveillance systems depend on reliable, noise-free transionospheric radio frequency channels. They can be severely impacted by small scale electron-density irregularities in the ionosphere, which cause both phase and amplitude scintillation. Basic tools used in planning and mitigation schemes are climatological in nature and thus may greatly over- and under-estimate the effects of scintillation in a given scenario. The results are summarized of a 3 year investigation into the feasibility of using in-situ observations of the ionosphere from the USAF DMSP satellite to calculate estimates of irregularity parameters that could be used to update scintillation models in near real time. Estimates for the level of intensity and phase scintillation on a transionospheric UHF radio link in the early evening auroral zone were calculated from DMSP Scintillation Meter (SM) data and compared to the levels actually observed. The intensity scintillation levels predicted and observed compared quite well, but the comparison with the phase scintillation data was complicated by low-frequency phase noise on the UHF radio link. Results are presented from analysis of DMSP SSIES data collected near Kwajalein Island in conjunction with a propagation-effects experiment. Preliminary conclusions to the assessment study are: (1) the DMSP SM data can be used to make quantitative estimates of the level of scintillation at auroral latitudes, and (2) it may be possible to use the data as a qualitative indicator of scintillation activity levels at equatorial latitudes.

Detailed Structure of the Outer Disk Around HD 169142 with Polarized Light in H-band

NASA Technical Reports Server (NTRS)

Momose, Munetake; Morita, Ayaka; Fukagawa, Misato; Muto, Takayuki; Takeuchi, Taku; Hashimoto, Jun; Honda, Mitsuhiko; Kudo, Tomoyuki; Okamoto, Yoshiko K.; Kanagawa, Kazuhiro D.;

Best methods for identification and treatment of PCOS.

PubMed

Artini, P G; Di Berardino, O M; Simi, G; Papini, F; Ruggiero, M; Monteleone, P; Cela, V

2010-02-01

The polycystic ovarian syndrome (PCOS) includes a wide spectrum of clinical symptoms and signs. Three different diagnostic classifications have been proposed to define this disease. The first one, published in 1990, known as the "NIH criteria" requires the simultaneous presence of hyperandrogenism and menstrual dysfunction in order to diagnose PCOS. Later on, in 2003, an expert panel met in Rotterdam and added to the previous criteria the presence of polycystic ovarian morphology detected by transvaginal ultrasonography. The later classification broadened the spectrum of PCOS and also included women with oligomenorrhea and PCO without hyperandrogenism or hyperandrogenism and PCO without menstrual dysfunction. Finally, the Androgen Excess Society, published in 2006 new diagnostic criteria which required the presence of clinical or biochemical hyperandrogenism, with either PCO or menstrual dysfunction to diagnose PCOS. This review focuses on the diagnostic techniques and methods of treatment for PCOS patients. Special attention is given to the role of insulin resistance and the potential utility of insulin sensitizers in management of the syndrome. The benefit and utmost importance of lifestyle modification for the long-term health of these women is stressed as well. It is hoped that some clarity in this regard will allow more women to not only be diagnosed and managed properly for their presenting symptoms (hirsutism, irregular menses, etc.), but also to be educated and managed for the continuing health risk of insulin resistance throughout their lives.

[Metformin efficiency for the adolescent PCOS treatment].

PubMed

Kedikova, S; Sirakov, M; Boyadzhieva, M

2012-01-01

PCOS is a polyglandular heterogenic metabolic condition, which frequency in adolescence is defined between 11-26%. There are some aspects of PCOS which can be seen in a regular puberty and vice versa. This makes the adolescent PCOS a condition which is rather complicated to diagnose as well as to treat. The pathophysiology of PCOS is not fully clarified, but is well established the fundamental role of the insulin resistance and the hyperinsulinemia. This fact explains the detailed investigations of the insulin sensitizers use for the PCOS treatment. Nevertheless there is insufficient experience with this medication group for the adolescent PCOS treatment in Bulgaria. To evaluate the Metformin efficiency for the adolescent PCOS treatment. This is a prospective study including 55 girls with menstrual irregularities aged between 13 and 18 years. None of the subjects had previously been diagnosed with any endocrine pathology or had received any hormonal treatment for at least three months prior to their evaluation. They have been evaluated according to the diagnostic criteria for PCOS in adolescence accepted in 2010. The incidence of PCOS in our research was 38.9%. In 66.7% of them the body mass index was higher than normal. Insulin resistance was diagnosed in 90.5%. The insulin resistance was improved in 80% of the PCOS patients after six months therapy with Metformin 2 x 850 mg/p.d. The menstrual function was regulated in 77.8% of the cases.

Children and adolescents referred for treatment of anxiety disorders: differences in clinical characteristics.

PubMed

Waite, Polly; Creswell, Cathy

2014-01-01

Reports of the clinical characteristics of children and adolescents with anxiety disorders are typically based on community populations or from clinical samples with exclusion criterion applied. Little is known about the clinical characteristics of children and adolescents routinely referred for treatment for anxiety disorders. Furthermore, children and adolescents are typically treated as one homogeneous group although they may differ in ways that are clinically meaningful. A consecutive series of children (n=100, aged 6-12 years) and adolescents (n=100, aged 13-18 years), referred to a routine clinical service, were assessed for anxiety and comorbid disorders, school refusal and parental symptoms of psychopathology. Children with a primary anxiety disorder were significantly more likely to be diagnosed with separation anxiety disorder than adolescents. Adolescents with a primary anxiety disorder had significantly higher self and clinician rated anxiety symptoms and had more frequent primary diagnoses of social anxiety disorder, diagnoses and symptoms of mood disorders, and irregular school attendance. Childhood and adolescence were considered categorically as distinct, developmental periods; in reality changes would be unlikely to occur in such a discrete manner. The finding that children and adolescents with anxiety disorders have distinct clinical characteristics has clear implications for treatment. Simply adapting treatments designed for children to make the materials more 'adolescent-friendly' is unlikely to sufficiently meet the needs of adolescents. Copyright © 2014 The Authors. Published by Elsevier B.V. All rights reserved.

Variational electric fields at low latitudes and their relation to spread F and plasma irregularities

NASA Technical Reports Server (NTRS)

Holtet, J. A.; Maynard, N. C.; Heppner, J. P.

1976-01-01

Recordings from OGO 6 show that electric field irregularities are frequently present between + or - 35 deg geomagnetic latitude in the 2000 - 0600 local time sector. The signatures are very clear, and are easily distinguished from the normal AC background noise, and whistler and emission activity. The spectral appearance of the fields makes it meaningful to distinguish between 3 different types of irregularities: strong irregularities, weak irregularities, and weak irregularities with a rising spectrum. Strong irregularities seem most likely to occur in regions where gradients in ionization are present. Changes in plasma composition, resulting in an increase in the mean ion mass, are also often observed in the irregularity regions. Comparison with ground based ionosondes indicates a connection between strong irregularities and low latitude spread F. A good correlation is also present between strong fields and small scale fluctuations in ionization, delta N/N 1 percent. From the data it appears as if a gradient driven instability is the most likely source of the strong irregularities.

A study on ionospheric scintillation near the EIA crest in relation to equatorial electrodynamics

NASA Astrophysics Data System (ADS)

Chatterjee, S.; Chakraborty, S. K.; Veenadhari, B.; Banola, S.

2014-02-01

Equatorial electrojet (EEJ) data, which are considered as a proxy index of equatorial electric field, are analyzed in conjunction with equatorial ionosonde, total electron content (TEC) and scintillation data near the equatorial ionization anomaly (EIA) crest for the equinoctial months of high solar activity years (2011-2012) to identify any precursor index of postsunset evolution of equatorial electron density irregularities and subsequent occurrence of scintillation near the northern EIA crest. Only geomagnetically quiet and normal electrojet days are considered. The diurnal profiles of EEJ on the scintillation days exhibit a secondary enhancement in the afternoon to presunset hours following diurnal peaks. A series of electrodynamical processes conducive for generation of irregularities emerge following secondary enhancement of EEJ. Latitudinal profile of TEC exhibits resurgence in EIA structure around the postsunset period. Diurnal TEC profile near the EIA crest resembles postsunset secondary enhancement on the days with afternoon enhancement in EEJ. Occurrence of equatorial spread F and postsunset scintillation near the EIA crest seems to follow the secondary enhancement events in EEJ. Both the magnitude and duration of enhanced EEJ are found to be important for postsunset intensification of EIA structure and subsequent occurrence of equatorial irregularities. A critical value combining the two may be considered an important precursor for postsunset occurrence of scintillation near the EIA crest. The results are validated using archived data for the years 1989-1990 and explained in terms of modulation effects of enhanced equatorial fountain.

Irregular Applications: Architectures & Algorithms

DOE Office of Scientific and Technical Information (OSTI.GOV)

Feo, John T.; Villa, Oreste; Tumeo, Antonino

Irregular applications are characterized by irregular data structures, control and communication patterns. Novel irregular high performance applications which deal with large data sets and require have recently appeared. Unfortunately, current high performance systems and software infrastructures executes irregular algorithms poorly. Only coordinated efforts by end user, area specialists and computer scientists that consider both the architecture and the software stack may be able to provide solutions to the challenges of modern irregular applications.

Spatially coupled low-density parity-check error correction for holographic data storage

NASA Astrophysics Data System (ADS)

Ishii, Norihiko; Katano, Yutaro; Muroi, Tetsuhiko; Kinoshita, Nobuhiro

2017-09-01

The spatially coupled low-density parity-check (SC-LDPC) was considered for holographic data storage. The superiority of SC-LDPC was studied by simulation. The simulations show that the performance of SC-LDPC depends on the lifting number, and when the lifting number is over 100, SC-LDPC shows better error correctability compared with irregular LDPC. SC-LDPC is applied to the 5:9 modulation code, which is one of the differential codes. The error-free point is near 2.8 dB and over 10-1 can be corrected in simulation. From these simulation results, this error correction code can be applied to actual holographic data storage test equipment. Results showed that 8 × 10-2 can be corrected, furthermore it works effectively and shows good error correctability.

A Computational Study on Porosity Evolution in Parts Produced by Selective Laser Melting

NASA Astrophysics Data System (ADS)

Tan, J. L.; Tang, C.; Wong, C. H.

2018-06-01

Selective laser melting (SLM) is a powder-bed additive manufacturing process that uses laser to melt powders, layer by layer to generate a functional 3D part. There are many different parameters, such as laser power, scanning speed, and layer thickness, which play a role in determining the quality of the printed part. These parameters contribute to the energy density applied on the powder bed. Defects arise when insufficient or excess energy density is applied. A common defect in these cases is the presence of porosity. This paper studies the formation of porosities when inappropriate energy densities are used. A computational model was developed to simulate the melting and solidification process of SS316L powders in the SLM process. Three different sets of process parameters were used to produce 800-µm-long melt tracks, and the characteristics of the porosities were analyzed. It was found that when low energy density parameters were used, the pores were found to be irregular in shapes and were located near the top surface of the powder bed. However, when high energy density parameters were used, the pores were either elliptical or spherical in shapes and were usually located near the bottom of the keyholes.

Effects of irregularity anisotropy on Faraday polarization fluctuations

NASA Technical Reports Server (NTRS)

Lee, M. C.; Nghiem, S. V.; Yoo, C.

1989-01-01

The previous model (Lee et al., 1982) of the Faraday polarization fluctuations (FPF) is extended after taking into account the anisotropic nature of the commonly observed, rodlike and sheetlike ionospheric irregularities. Striking effects of irregularity anisotropy are found in the longitudinal radio propagation. However, if the wave propagation angle is not small (say, greater than 5 deg), the effects of irregularity anisotropy on FPF introduced by rodlike irregularities weaken significantly, while those caused by sheetlike irregularities remain prominent. Therefore, under the same ionospheric propagation conditions, sheetlike ionospheric irregularities are more effective than rodlike ionospheric irregularities in causing the FPF of radio waves. It is expected that intense FPF of VHF radio signals can be observed not only near the equatorial anomaly but also in the auroral region.

Using a Calculated Pulse Rate with an Artificial Neural Network to Detect Irregular Interbeats.

PubMed

Yeh, Bih-Chyun; Lin, Wen-Piao

2016-03-01

Heart rate is an important clinical measure that is often used in pathological diagnosis and prognosis. Valid detection of irregular heartbeats is crucial in the clinical practice. We propose an artificial neural network using the calculated pulse rate to detect irregular interbeats. The proposed system measures the calculated pulse rate to determine an "irregular interbeat on" or "irregular interbeat off" event. If an irregular interbeat is detected, the proposed system produces a danger warning, which is helpful for clinicians. If a non-irregular interbeat is detected, the proposed system displays the calculated pulse rate. We include a flow chart of the proposed software. In an experiment, we measure the calculated pulse rates and achieve an error percentage of < 3% in 20 participants with a wide age range. When we use the calculated pulse rates to detect irregular interbeats, we find such irregular interbeats in eight participants.

The Equatorial Scintillations and Space Weather Effects on its Generation during Geomagnetic Storms

NASA Astrophysics Data System (ADS)

Biktash, Lilia

Great diversity of the ionospheric phenomena leads to a variety of irregularity types with spatial size from many thousands of kilometers to few centimeters and lifetimes from days to fractions of second. Since the ionosphere strongly influences the propagation of radio waves, signal distortions caused by these irregularities affect short-wave transmissions on Earth, transiono-spheric satellite communications and navigation. In this work the solar wind and the equatorial ionosphere parameters, Kp, Dst, AU, AL indices characterized contribution of different mag-netospheric and ionospheric currents to the H-component of geomagnetic field are examined to test the space weather effect on the generation of ionospheric irregularities producing VLF scintillations. According to the results of the current statistical studies, one can predict scintil-lations from Aarons' criteria using the Dst index, which mainly depicts the magnetospheric ring current field. To amplify Aarons' criteria or to propose new criteria for predicting scintillation characteristics is the question. In the present phase of the experimental investigations of elec-tron density irregularities in the ionosphere new ways are opened up because observations in the interaction between the solar wind -magnetosphere -ionosphere during magnetic storms have progressed greatly. We have examined scintillation relation to magnetospheric and ionospheric currents and show that the factor, which presents during magnetic storms to fully inhibit scin-tillation, is the positive Bz-component of the IMF. During the positive Bz IMF F layer cannot raise altitude where scintillations are formed. The auroral indices and Kp do better for the prediction of the ionospheric scintillations at the equator. The interplanetary magnetic field data and models can be used to explain the relationship between the equatorial ionospheric parameters, h'F, foF2, and the equatorial geomagnetic variations with the polar ionosphere cur-rents and the solar wind. Taking into account the time delay between the solar wind and the ionosphere phenomena, the relationship between the solar wind and the ionosphere parameters can be used for predicting of scintillations.

Mutual information estimation for irregularly sampled time series

NASA Astrophysics Data System (ADS)

Rehfeld, K.; Marwan, N.; Heitzig, J.; Kurths, J.

2012-04-01

For the automated, objective and joint analysis of time series, similarity measures are crucial. Used in the analysis of climate records, they allow for a complimentary, unbiased view onto sparse datasets. The irregular sampling of many of these time series, however, makes it necessary to either perform signal reconstruction (e.g. interpolation) or to develop and use adapted measures. Standard linear interpolation comes with an inevitable loss of information and bias effects. We have recently developed a Gaussian kernel-based correlation algorithm with which the interpolation error can be substantially lowered, but this would not work should the functional relationship in a bivariate setting be non-linear. We therefore propose an algorithm to estimate lagged auto and cross mutual information from irregularly sampled time series. We have extended the standard and adaptive binning histogram estimators and use Gaussian distributed weights in the estimation of the (joint) probabilities. To test our method we have simulated linear and nonlinear auto-regressive processes with Gamma-distributed inter-sampling intervals. We have then performed a sensitivity analysis for the estimation of actual coupling length, the lag of coupling and the decorrelation time in the synthetic time series and contrast our results to the performance of a signal reconstruction scheme. Finally we applied our estimator to speleothem records. We compare the estimated memory (or decorrelation time) to that from a least-squares estimator based on fitting an auto-regressive process of order 1. The calculated (cross) mutual information results are compared for the different estimators (standard or adaptive binning) and contrasted with results from signal reconstruction. We find that the kernel-based estimator has a significantly lower root mean square error and less systematic sampling bias than the interpolation-based method. It is possible that these encouraging results could be further improved by using non-histogram mutual information estimators, like k-Nearest Neighbor or Kernel-Density estimators, but for short (<1000 points) and irregularly sampled datasets the proposed algorithm is already a great improvement.

A 27-year-old woman with a diagnosis of polycystic ovary syndrome.

PubMed

Legro, Richard S

2007-02-07

Ms R, a 27-year-old woman with polycystic ovary syndrome (PCOS) diagnosed after irregular menses, hirsutism, and polycystic ovaries, is concerned about weight gain despite regular exercise and watching her diet. Prescribed oral contraceptives to regulate her menses and help reduce her androgen levels, she wants to know the alternatives for treatment of PCOS. The varying definitions of PCOS and its heterogeneity confound the interpretation of studies on PCOS. Specific diagnostic criteria have been established based on expert opinion but have not been validated. Several commonly performed laboratory tests are generally unhelpful and the pathophysiology is poorly understood. Treatment options for Ms R, including those that may affect her weight gain, are reviewed and implications for future fertility are discussed.

Polycystic Ovary Syndrome in Adolescence

PubMed Central

Buggs, Colleen; Rosenfield, Robert L.

2012-01-01

Polycystic ovary syndrome (PCOS) is a syndrome of variable combinations of menstrual irregularity, hirsutism or acne, and obesity. It can be diagnosed in adolescence and has early childhood antecedents. PCOS is the single most common endocrine cause of anovulatory infertility and a major risk factor for the metabolic syndrome and, in turn, development of type 2 diabetes mellitus (T2DM) in women. Thus, it appears that PCOS increases a woman’s risk of developing cardiovascular disease. Therefore, identifying girls at risk for PCOS and implementing treatment early in the development of PCOS may be an effective means of preventing some of the long-term complications associated with this syndrome. This article reviews the definition, clinical features, diagnosis, and treatment of PCOS. PMID:16085166

Repair of Irregularly Irregular Astigmatism by Transepithelial Phototherapeutic Keratectomy.

PubMed

Guglielmetti, Stefano; Kirton, Amy; Reinstein, Dan Z; Carp, Glenn I; Archer, Timothy J

2017-10-01

To evaluate the outcome of transepithelial phototherapeutic keratectomy (PTK) in the management of irregularly irregular astigmatism. This was a case series of two patients who underwent transepithelial PTK for irregularly irregular astigmatism. In the first case, the patient complained of diplopia due to corneal scarring caused by a metallic foreign body injury. The topography demonstrated irregularly irregular astigmatism with significant asymmetry in the inferotemporal to superonasal axis. In the second case, the patient complained of blurred vision and ghosting caused by significant central epithelial ingrowth through a buttonhole LASIK flap, which was causing a localized irregularity on topography. Due to the localized nature of the irregularities, a transepithelial PTK treatment was preferred to custom ablation given the degree of epithelial masking present. Transepithelial PTK was performed in both cases using the Schwind Amaris 500E excimer laser (Schwind eye-tech-solutions, Kleinostheim, Germany) and an 8-mm optical zone. The ablation depth was planned to reach the depth of the epithelium using a stepwise protocol, reviewing the pattern of the remaining epithelium and regularity of the stromal surface between each ablation. A marked improvement in the regularity of the topography was achieved in both cases, with only regular astigmatism remaining. Both patients reported a subjective improvement in quality of vision and the corrected distance visual acuity improved by one and two lines, respectively. Transepithelial PTK was effective in treating these cases of localized irregularly irregular astigmatism, achieving both objective and subjective improvement in vision. Compensatory epithelial remodeling over the irregularities enabled the transepithelial PTK approach to target the stromal surface irregularities. [J Refract Surg. 2017;33(10):714-719.]. Copyright 2017, SLACK Incorporated.

Measuring interdependence in ambulatory care.

PubMed

Katerndahl, David; Wood, Robert; Jaen, Carlos R

2017-04-01

Complex systems differ from complicated systems in that they are nonlinear, unpredictable and lacking clear cause-and-effect relationships, largely due to the interdependence of their components (effects of interconnectedness on system behaviour and consequences). The purpose of this study was to demonstrate the potential for network density to serve as a measure of interdependence, assess its concurrent validity and test whether the use of valued or binary ties yields better results. This secondary analysis used the 2010 National Ambulatory Care Medical Survey to assess interdependence of 'top 20' diagnoses seen and medications prescribed for 14 specialties. The degree of interdependence was measured as the level of association between diagnoses and drug interactions among medications. Both valued and binary network densities were computed for each specialty. To assess concurrent validity, these measures were correlated with previously-derived valid measures of complexity of care using the same database, adjusting for diagnosis and medication diversity. Partial correlations between diagnosis density, and both diagnosis and total input complexity, were significant, as were those between medication density and both medication and total output complexity; for both diagnosis and medication densities, adjusted correlations were higher for binary rather than valued densities. This study demonstrated the feasibility and validity of using network density as a measure of interdependence. When adjusted for measure diversity, density-complexity correlations were significant and higher for binary than valued density. This approach complements other methods of estimating complexity of care and may be applicable to unique settings. © 2015 John Wiley & Sons, Ltd.

The PCOS Patients differ in Lipid Profile According to their Phenotypes.

PubMed

Spałkowska, Magdalena; Mrozińska, Sandra; Gałuszka-Bednarczyk, Anna; Gosztyła, Katarzyna; Przywara, Agnieszka; Guzik, Justyna; Janeczko, Marek; Milewicz, Tomasz; Wojas-Pelc, Anna

2018-01-31

Polycystic ovary syndrome (PCOS) affects 4-18% of women of reproductive age. The number of reports exploring the lipid profiles among PCOS patients and number of studied patients are limited. The aim of our study was to assess the lipid profile separately in lean and non-lean women with polycystic ovary syndrome divided according to hyperandrogenemia, defined as free androgen index (FAI)≥5. The second aim was to compare the lipid profiles among lean and non-lean PCOS patients with respect to hyperandrogenemia and regularity of menstruation cycles. We evaluated 232 patients from Department of Endocrinological Gynecology, Jagiellonian University Medical College in Krakow diagnosed with PCOS. The population consisted of 166 lean and 66 non-lean women. We observed higher levels of total cholesterol, high-density lipoprotein cholesterol (HDL-C) in lean patients with FAI<5 than in lean patients with FAI≥5. There were no differences in lipid profile between non-lean patients with FAI≥5 and non-lean patients with FAI<5. Among lean patients higher total cholesterol levels were observed in those with irregular menstruation cycles and FAI<5 than in patients with FAI≥5 and regular cycles. There were no differences in lipid profiles between four phenotypes among non-lean PCOS patients. The results of our study showed differences in lipid profile between lean PCOS patients according to their phenotype based on androgens' level. This effect was abandoned by fat tissue mass in non-lean ones. Further studies should be conducted to explore these associations. © Georg Thieme Verlag KG Stuttgart · New York.

Natural History of Aging in Cornelia de Lange Syndrome

PubMed Central

KLINE, ANTONIE D.; GRADOS, MARCO; SPONSELLER, PAUL; LEVY, HOWARD P.; BLAGOWIDOW, NATALIE; SCHOEDEL, CHRISTIANNE; RAMPOLLA, JONI; CLEMENS, DOUGLAS K.; KRANTZ, IAN; KIMBALL, AMY; PICHARD, CARMEN; TUCHMAN, DAVID

2016-01-01

Observations about the natural history of aging in Cornelia de Lange syndrome (CdLS) are made, based on 49 patients from a multidisciplinary clinic for adolescents and adults. The mean age was 17 years. Although most patients remain small, obesity may develop. Gastroesophageal reflux persists or worsens, and there are early long-term sequelae, including Barrett esophagus in 10%; other gastrointestinal findings include risk for volvulus, rumination, and chronic constipation. Submucous cleft palate was found in 14%, most undetected before our evaluation. Chronic sinusitis was noted in 39%, often with nasal polyps. Blepharitis improves with age; cataracts and detached retina may occur. Decreased bone density is observed, with occasional fractures. One quarter have leg length discrepancy and 39% scoliosis. Most females have delayed or irregular menses but normal gynecologic exams and pap smears. Benign prostatic hypertrophy occurred in one male prior to 40 years. The phenotype is variable, but there is a distinct pattern of facial changes with aging. Premature gray hair is frequent; two patients had cutis verticis gyrata. Behavioral issues and specific psychiatric diagnoses, including self-injury, anxiety, attention-deficit disorder, autistic features, depression, and obsessive-compulsive behavior, often worsen with age. This work presents some evidence for accelerated aging in CdLS. Of 53% with mutation analysis, 55% demonstrate a detectable mutation in NIPBL or SMC1A. Although no specific genotype–phenotype correlations have been firmly established, individuals with missense mutations in NIPBL and SMC1A appear milder than those with other mutations. Based on these observations, recommendations for clinical management of adults with CdLS are made. PMID:17640042

Luminous clusters of Wolf-Rayet stars in the SBmIII galaxy NGC 4214

NASA Technical Reports Server (NTRS)

Sargent, Wallace L. W.; Filippenko, Alexei V.

1991-01-01

Observations are reported of strong broad emission lines attributed to WR stars in the spectra of several bright knots in the nearby Magellanic irregular galaxy NGC 4214 (classified as type SBmIII), in addition to the emission produced by the more prevalent WN stars). Data are presented on measurements of the line fluxes, the line equivalent widths, and continuum flux densities in the four observed knots, showing that the strongest WR lines generally appear in knots having the most luminous stellar continuum. The significance of this observation is discussed.

Studies of the Origin and Evolution of Ionospheric Irregularities and Their Effects on AF Systems

DTIC Science & Technology

2008-06-30

34The JB2006 empirical thermospheric density model," by B . R. Bowman, W. K . Tobiska, F. A. Marcos, and C. E. Valladares, J. Atm. and Solar-Terr...during the super geomagnetic storm on 20 November 2003, Ann. Geophys, 25, 863-873, 2007. Bowman, B . R., W. K . Tobiska, F. A. Marcos, and C. E...at middle and equatorial latitudes, J. Geophys. Res., 106, 30,389. Devasia, C. V., N. Jyoti, K . S. V. Subbarao , K . S. Viswanathan, D. Tiwari, and R

Superposition of \\sqrt{13}\\times \\sqrt{13} and 3 × 3 supermodulations in TaS2 probed by scanning tunneling microscopy

NASA Astrophysics Data System (ADS)

Fujisawa, Y.; Iwasaki, T.; Fujii, D.; Ohta, S.; Iwashita, J.; Fujita, T.; Nakata, M.; Kishimoto, K.; Demura, S.; Sakata, H.

2018-03-01

We report on a scanning tunnelling microscopy study of TaS2 at 4.2 K. A surface prepared by cleavage showed a superimposed pattern of two types of charge density waves with 3a 0 × 3a 0 and \\sqrt{13}{a}0× \\sqrt{13}{a}0 periodicity, which had never been observed previously. We attribute the superposition to regular stacking of 4H b polytypes or irregular stacking of 2H and 4H b layers.

Fabrication of Nb/Pb structures through ultrashort pulsed laser deposition

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gontad, Francisco; Lorusso, Antonella, E-mail: antonella.lorusso@le.infn.it; Perrone, Alessio

This work reports the fabrication of Nb/Pb structures with an application as photocathode devices. The use of relatively low energy densities for the ablation of Nb with ultrashort pulses favors the reduction of droplets during the growth of the film. However, the use of laser fluences in this ablation regime results in a consequent reduction in the average deposition rate. On the other hand, despite the low deposition rate, the films present a superior adherence to the substrate and an excellent coverage of the irregular substrate surface, avoiding the appearance of voids or discontinuities on the film surface. Moreover, themore » low energy densities used for the ablation favor the growth of nanocrystalline films with a similar crystalline structure to the bulk material. Therefore, the use of low ablation energy densities with ultrashort pulses for the deposition of the Nb thin films allows the growth of very adherent and nanocrystalline films with adequate properties for the fabrication of Nb/Pb structures to be included in superconducting radiofrequency cavities.« less

An automated system for the study of ionospheric spatial structures

NASA Astrophysics Data System (ADS)

Belinskaya, I. V.; Boitman, O. N.; Vugmeister, B. O.; Vyborova, V. M.; Zakharov, V. N.; Laptev, V. A.; Mamchenko, M. S.; Potemkin, A. A.; Radionov, V. V.

The system is designed for the study of the vertical distribution of electron density and the parameters of medium-scale ionospheric irregularities over the sounding site as well as the reconstruction of the spatial distribution of electron density within the range of up to 300 km from the sounding location. The system comprises an active central station as well as passive companion stations. The central station is equipped with the digital ionosonde ``Basis'', the measuring-and-computing complex IVK-2, and the receiver-recorder PRK-3M. The companion stations are equipped with receivers-recorders PRK-3. The automated comlex software system includes 14 subsystems. Data transfer between them is effected using magnetic disk data sets. The system is operated in both ionogram mode and Doppler shift and angle-of-arrival mode. Using data obtained in these two modes, the reconstruction of the spatial distribution of electron density in the region is carried out. Reconstruction is checked for accuracy using data from companion stations.

A study of the cleft region using synoptic ionospheric plasma data obtained by the polar orbiting satellites Aeros-B and Isis-2

NASA Technical Reports Server (NTRS)

Kist, R.; Klumpar, D.

1980-01-01

The concentrations of O(+) and NO(+) in the dayside high-latitude cleft region of the ionosphere are investigated based on synoptic particle and plasma measurements obtained by the polar orbiting Aeros-B and Isis-2 satellites. At a time when the orbital planes of the satellites are almost at right angles to each other, three maxima in ion temperature are observed, with two of them accompanied by an increased electron temperature and electron density irregularities, and the density of the molecular ions NO(+) and O2(+) is found to increase at the expense of O(+) density. Results are discussed in terms of a theory relating perpendicular electric fields to oxygen atom reaction rates. Systematic analysis of the Aeros data base reveals 14 additional instances of O(+) to NO(+) conversion, with a large variety of forms and structures reflecting the complex structure and dynamics of the high-latitude dayside ionosphere.

Structural and ultrastructural study of rat testes influenced by electromagnetic radiation.

PubMed

Almášiová, Viera; Holovská, Katarína; Cigánková, Viera; Račeková, Enikö; Fabianová, Kamila; Martončíková, Marcela

2014-01-01

This study was conducted to investigate the influence of whole-body electromagnetic radiation (EMR) on testicular parenchyma of Wistar rats. Sexually mature rats were subjected to pulsed electromagnetic field at frequency of 2.45 GHz and mean power density 2.8 mW/cm(2) by 3-h daily applications for 3 wk. Tissue samples were obtained 3 h after the last irradiation and processed by histological techniques for light and transmission electron microscopy. Testes showed apparent degenerative changes of seminiferous epithelium. The seminiferous tubules were mostly irregular in shape, and seminiferous epithelium contained a number of empty spaces of different size. Subsequently, groups of sloughed epithelial cells were often found inside the lumina of tubules. Except for relatively unchanged Sertoli cells, some locations of basal compartment of seminiferous epithelium contained shriveled Sertoli cells with dark cytoplasm. These areas showed degenerative features including necrotizing and shriveled spermatogonia surrounded by empty irregular spaces, and undulating basement membrane. The intertubular spaces were enlarged but interstitial Leydig cells did not show any marked morphological changes. Evidence demonstrates the adverse effects of EMR on testicular parenchyma in rats.

Method for producing ceramic particles and agglomerates

DOEpatents

Phillips, Jonathan; Gleiman, Seth S.; Chen, Chun-Ku

2001-01-01

A method for generating spherical and irregularly shaped dense particles of ceramic oxides having a controlled particle size and particle size distribution. An aerosol containing precursor particles of oxide ceramics is directed into a plasma. As the particles flow through the hot zone of the plasma, they melt, collide, and join to form larger particles. If these larger particles remain in the hot zone, they continue melting and acquire a spherical shape that is retained after they exit the hot zone, cool down, and solidify. If they exit the hot zone before melting completely, their irregular shape persists and agglomerates are produced. The size and size distribution of the dense product particles can be controlled by adjusting several parameters, the most important in the case of powder precursors appears to be the density of powder in the aerosol stream that enters the plasma hot zone. This suggests that particle collision rate is responsible for determining ultimate size of the resulting sphere or agglomerate. Other parameters, particularly the gas flow rates and the microwave power, are also adjusted to control the particle size distribution.

Modelling ionospheric scintillation under the crest of the equatorial anomaly

NASA Astrophysics Data System (ADS)

Alfonsi, L.; Wernik, A. W.; Materassi, M.; Spogli, L.

2017-10-01

WAM is realized making use of the plasma density data collected via the retarding potential analyser on board the Dynamics Explorer 2 spacecraft, capable to model the scintillation climatology over the northern hemisphere high latitude ionosphere. More recently, WAM has been tuned to model the ionospheric scintillations also over the equatorial latitudes. The effort has been done to support the CIGALA (Concept for Ionospheric Scintillation Mitigation for Professional GNSS in Latin America) project in the assessment of the scintillations climatology over Latin America. The concept of the new release of WAM is the same already adopted for the high latitudes: the in situ measurements, supplemented with an ionospheric model and with the irregularity anisotropy model, are treated to describe the morphology of scintillation, provided a suitable propagation model is used. Significant differences have been included in the low latitudes release to account for the anisotropy of the irregularities and for strong scattering regime. The paper describes the new WAM formulation and presents comparisons of the model predictions with the actual measurements collected in Brazil.

Predawn plasma bubble cluster observed in Southeast Asia

NASA Astrophysics Data System (ADS)

Watthanasangmechai, Kornyanat; Yamamoto, Mamoru; Saito, Akinori; Tsunoda, Roland; Yokoyama, Tatsuhiro; Supnithi, Pornchai; Ishii, Mamoru; Yatini, Clara

2016-06-01

Predawn plasma bubble was detected as deep plasma depletion by GNU Radio Beacon Receiver (GRBR) network and in situ measurement onboard Defense Meteorological Satellite Program F15 (DMSPF15) satellite and was confirmed by sparse GPS network in Southeast Asia. In addition to the deep depletion, the GPS network revealed the coexisting submesoscale irregularities. A deep depletion is regarded as a primary bubble. Submesoscale irregularities are regarded as secondary bubbles. Primary bubble and secondary bubbles appeared together as a cluster with zonal wavelength of 50 km. An altitude of secondary bubbles happened to be lower than that of the primary bubble in the same cluster. The observed pattern of plasma bubble cluster is consistent with the simulation result of the recent high-resolution bubble (HIRB) model. This event is only a single event out of 76 satellite passes at nighttime during 3-25 March 2012 that significantly shows plasma depletion at plasma bubble wall. The inside structure of the primary bubble was clearly revealed from the in situ density data of DMSPF15 satellite and the ground-based GRBR total electron content.

Wide-Field Structure of Local Group Dwarf Irregular Galaxy IC1613

NASA Astrophysics Data System (ADS)

Pucha, Ragadeepika; Carlin, Jeffrey; Willman, Beth; Sand, David J.; Bechtol, Keith

2018-01-01

IC1613 is a typical dwarf irregular galaxy in the Local Group. Being an isolated dwarf, as opposed to the dwarfs around the Milky Way, it is likely to be subjected to fewer strong environmental effects. As a result, it serves as a good prototype for the study of the structure and evolution of dwarf galaxies. We present g- and i- band photometry from deep imaging of four fields around IC1613, that resolved stars up to ~ 4 magnitudes fainter than the tip of the RGB. This photometry was obtained using Hyper-Suprime Cam (HSC) on the Subaru Telescope. The large (1.5o) field-of-view of HSC provides us with a unique opportunity to study the wide-field structure of this dwarf galaxy. This project explores the structure of IC1613 to radii of about ~ 25 kpc using different types of stellar tracers. The aim is to search for evidence of a stellar halo or stellar over-densities around IC1613. The relative contributions of the different stellar populations as a function of position in IC1613 are also shown.

An Overview of Scientific and Space Weather Results from the Communication/Navigation Outage Forecasting System (C/NOFS) Mission

NASA Technical Reports Server (NTRS)

Pfaff, R.; de la Beaujardiere, O.; Hunton, D.; Heelis, R.; Earle, G.; Strauss, P.; Bernhardt, P.

2012-01-01

The Communication/Navigation Outage Forecasting System (C/NOFS) Mission of the Air Force Research Laboratory is described. C/NOFS science objectives may be organized into three categories: (1) to understand physical processes active in the background ionosphere and thermosphere in which plasma instabilities grow; (2) to identify mechanisms that trigger or quench the plasma irregularities responsible for signal degradation; and (3) to determine how the plasma irregularities affect the propagation of electromagnetic waves. The satellite was launched in April, 2008 into a low inclination (13 deg), elliptical (400 x 850 km) orbit. The satellite sensors measure the following parameters in situ: ambient and fluctuating electron densities, AC and DC electric and magnetic fields, ion drifts and large scale ion composition, ion and electron temperatures, and neutral winds. C/NOFS is also equipped with a GPS occultation receiver and a radio beacon. In addition to the satellite sensors, complementary ground-based measurements, theory, and advanced modeling techniques are also important parts of the mission. We report scientific and space weather highlights of the mission after nearly four years in orbit

Case study of simultaneous observations of sporadic sodium layer, E-region field-aligned irregularities and sporadic E layer at low latitude of China

NASA Astrophysics Data System (ADS)

Xie, H. Y.; Ning, B. Q.; Zhao, X. K.; Hu, L. H.

2017-03-01

Using the Na lidar at Haikou (20.0°N, 110.3°E), the VHF coherent radar and the digital ionosonde both at Sanya (18.4°N, 109.6°E), cases of simultaneous observations of sporadic sodium layer (SSL), E-region field-aligned irregularities (FAI) and sporadic E layer (Es) in the mesosphere and lower thermosphere (MLT) region at low latitude of China are studied. It is found that SSL occurs simultaneously or follows the enhancement of Es and FAI. The Es, FAI and SSL descend slowly with time which is mostly controlled by the diurnal tide (DT). Besides, the interaction of gravity wave (GW) with tides can cause oscillations in FAI and SSL. Our observations support the neutralization of ions for SSL formation: when the metallic ions layer descents to the altitudes where models predict, the sodium ions convert rapidly to atomic Na that may form an SSL event. Moreover, the SSL peak density will increase (decrease) in the convergence (divergence) vertical shear region of zonal wind.

Star Formation in Irregular Galaxies.

ERIC Educational Resources Information Center

Hunter, Deidre; Wolff, Sidney

1985-01-01

Examines mechanisms of how stars are formed in irregular galaxies. Formation in giant irregular galaxies, formation in dwarf irregular galaxies, and comparisons with larger star-forming regions found in spiral galaxies are considered separately. (JN)

Smart-Phone Based Magnetic Levitation for Measuring Densities

PubMed Central

Knowlton, Stephanie; Yu, Chu Hsiang; Jain, Nupur

2015-01-01

Magnetic levitation, which uses a magnetic field to suspend objects in a fluid, is a powerful and versatile technology. We develop a compact magnetic levitation platform compatible with a smart-phone to separate micro-objects and estimate the density of the sample based on its levitation height. A 3D printed attachment is mechanically installed over the existing camera unit of a smart-phone. Micro-objects, which may be either spherical or irregular in shape, are suspended in a paramagnetic medium and loaded in a microcapillary tube which is then inserted between two permanent magnets. The micro-objects are levitated and confined in the microcapillary at an equilibrium height dependent on their volumetric mass densities (causing a buoyancy force toward the edge of the microcapillary) and magnetic susceptibilities (causing a magnetic force toward the center of the microcapillary) relative to the suspending medium. The smart-phone camera captures magnified images of the levitating micro-objects through an additional lens positioned between the sample and the camera lens cover. A custom-developed Android application then analyzes these images to determine the levitation height and estimate the density. Using this platform, we were able to separate microspheres with varying densities and calibrate their levitation heights to known densities to develop a technique for precise and accurate density estimation. We have also characterized the magnetic field, the optical imaging capabilities, and the thermal state over time of this platform. PMID:26308615

Smart-Phone Based Magnetic Levitation for Measuring Densities.

PubMed

Knowlton, Stephanie; Yu, Chu Hsiang; Jain, Nupur; Ghiran, Ionita Calin; Tasoglu, Savas

2015-01-01

Magnetic levitation, which uses a magnetic field to suspend objects in a fluid, is a powerful and versatile technology. We develop a compact magnetic levitation platform compatible with a smart-phone to separate micro-objects and estimate the density of the sample based on its levitation height. A 3D printed attachment is mechanically installed over the existing camera unit of a smart-phone. Micro-objects, which may be either spherical or irregular in shape, are suspended in a paramagnetic medium and loaded in a microcapillary tube which is then inserted between two permanent magnets. The micro-objects are levitated and confined in the microcapillary at an equilibrium height dependent on their volumetric mass densities (causing a buoyancy force toward the edge of the microcapillary) and magnetic susceptibilities (causing a magnetic force toward the center of the microcapillary) relative to the suspending medium. The smart-phone camera captures magnified images of the levitating micro-objects through an additional lens positioned between the sample and the camera lens cover. A custom-developed Android application then analyzes these images to determine the levitation height and estimate the density. Using this platform, we were able to separate microspheres with varying densities and calibrate their levitation heights to known densities to develop a technique for precise and accurate density estimation. We have also characterized the magnetic field, the optical imaging capabilities, and the thermal state over time of this platform.

Working under daylight intensity lamp: an occupational risk for developing circadian rhythm sleep disorder?

PubMed

Doljansky, J T; Kannety, H; Dagan, Y

2005-01-01

A 47-yr-old male was admitted to the Institute for Fatigue and Sleep Medicine complaining of severe fatigue and daytime sleepiness. His medical history included diagnosis of depression and chronic fatigue syndrome. Antidepressant drugs failed to improve his condition. He described a gradual evolvement of an irregular sleep-wake pattern within the past 20 yrs, causing marked distress and severe impairment of daily functioning. He had to change to a part-time position 7 yrs ago, because he was unable to maintain a regular full-time job schedule. A 10-day actigraphic record revealed an irregular sleep-wake pattern with extensive day-to-day variability in sleep onset time and sleep duration, and a 36 h sampling of both melatonin level and oral temperature (12 samples, once every 3 h) showed abnormal patterns, with the melatonin peak around noon and oral temperature peak around dawn. Thus, the patient was diagnosed as suffering from irregular sleep-wake pattern. Treatment with melatonin (5 mg, 2 h before bedtime) did not improve his condition. A further investigation of the patient's daily habits and environmental conditions revealed two important facts. First, his occupation required work under a daylight intensity lamp (professional diamond-grading equipment of more than 8000 lux), and second, since the patient tended to work late, the exposure to bright light occurred mostly at night. To recover his circadian rhythmicity and stabilize his sleep-wake pattern, we recommended combined treatment consisting of evening melatonin ingestion combined with morning (09:00 h) bright light therapy (0800 lux for 1 h) plus the avoidance of bright light in the evening. Another 10-day actigraphic study done only 1 wk after initiating the combined treatment protocol revealed stabilization of the sleep-wake pattern with advancement of sleep phase. In addition, the patient reported profound improvement in maintaining wakefulness during the day. This case study shows that chronic exposure to bright light at the wrong biological time, during the nighttime, may have serious effects on the circadian sleep-wake patterns and circadian time structure. Therefore, night bright light exposure must be considered to be a risk factor of previously unrecognized occupational diseases of altered circadian time structure manifested as irregularity of the 24 h sleep-wake cycle and melancholy.

Demonstration of x-ray fluorescence imaging of a high-energy-density plasma.

PubMed

MacDonald, M J; Keiter, P A; Montgomery, D S; Biener, M M; Fein, J R; Fournier, K B; Gamboa, E J; Klein, S R; Kuranz, C C; LeFevre, H J; Manuel, M J-E; Streit, J; Wan, W C; Drake, R P

2014-11-01

Experiments at the Trident Laser Facility have successfully demonstrated the use of x-ray fluorescence imaging (XRFI) to diagnose shocked carbonized resorcinol formaldehyde (CRF) foams doped with Ti. One laser beam created a shock wave in the doped foam. A second laser beam produced a flux of vanadium He-α x-rays, which in turn induced Ti K-shell fluorescence within the foam. Spectrally resolved 1D imaging of the x-ray fluorescence provided shock location and compression measurements. Additionally, experiments using a collimator demonstrated that one can probe specific regions within a target. These results show that XRFI is a capable alternative to path-integrated measurements for diagnosing hydrodynamic experiments at high energy density.

A Cellular Automaton model for pedestrian counterflow with swapping

NASA Astrophysics Data System (ADS)

Tao, Y. Z.; Dong, L. Y.

2017-06-01

In this paper, we propose a new floor field Cellular Automaton (CA) model with considering the swapping behaviors of pedestrians. The neighboring pedestrians in opposite directions take swapping in a probability decided by the linear density of pedestrian flow. The swapping which happens simultaneously with the normal movement is introduced to eliminate the gridlock in low density region. Numerical results show that the fundamental diagram is in good agreement with the measured data. Then the model is applied to investigate the counterflow and four typical states such as free flow, lane, intermediate and congestion states are found. More attention is paid on the intermediate state which lane-formation and local congestions switch in an irregular manner. The swapping plays a vital role in reducing the gridlock. Furthermore, the influence of the corridor size and individual's eyesight on counterflow are discussed in detail.

Effect of Fe-doping on CDW state in 1T-TaS2 investigated by STM/STS

NASA Astrophysics Data System (ADS)

Fujisawa, Y.; Shimabukuro, T.; Kojima, H.; Kobayashi, K.; Demura, S.; Sakata, H.

2017-07-01

1T-TaS2 has been known to undergo Mott transition from nearly commensurate charge density wave (CDW) state to commensurate CDW state at about 200 K. Recently, Fe doping was found to suppress the Mott transition and induce superconductivity. In this study, we report on the scanning tunneling microscopy (STM) and spectroscopy (STS) study on Fe doped 1T-TaS2 with different Fe concentration. STM observations reveal that the CDW superlattice becomes irregular as increasing Fe concentration. STS measurements uncover the spatial change in the local density of state (LDOS). We find two types of David-star: one has symmetric LDOS with respect to Fermi energy, and the other has asymmetric one. We identify that the asymmetric spectrum is due to an Fe dopant.

Differentiation of nonneoplastic and neoplastic gallbladder polyps 1 cm or bigger with multi-detector row computed tomography.

PubMed

Park, Ko Woon; Kim, Seong Hyun; Choi, Seong Ho; Lee, Won Jae

2010-01-01

To evaluate useful computed tomographic features to differentiate nonneoplastic and neoplastic gallbladder polyps 1 cm or bigger. Thirty-one patients with 32 nonneoplastic polyps and 67 patients with 73 neoplastic polyps 1 cm or bigger underwent unenhanced and dual-phase (arterial and portal venous phases) multi-detector row computed tomography. Gallbladder polyps were diagnosed by cholecystectomy. Computed tomographic features including size (1.5 cm), surface (smooth or irregular), shape (pedunculated or sessile), accompanying wall thickening, basal indentation, perception on unenhanced images, and enhancement pattern between 2 groups were compared using univariate and multivariate analyses. On univariate analysis, age 55 years or older (P = 0.0019), size bigger than 1.5 cm (P < 0.0001), irregular surface (P = 0.0033), sessile shape (P = 0.0016), accompanying wall thickening (P = 0.0056), basal indentation (P = 0.0236), and perception on unenhanced images (P < 0.0001) were significantly more frequent in neoplastic polyps as compared with nonneoplastic polyps. On multivariate analysis, size bigger than 1.5 cm (P = 0.0260), sessile shape (P = 0.0397), and perception on unenhanced images (P < 0.0001) were statistically significant. Size bigger than 1.5 cm, sessile shape, and perception on unenhanced images are the main factors that differentiate neoplastic from nonneoplastic gallbladder polyps 1 cm or bigger.

The Wire-Grasping Method as a New Technique for Forceps Biopsy of Biliary Strictures: A Prospective Randomized Controlled Study of Effectiveness

PubMed Central

Yamashita, Yasunobu; Ueda, Kazuki; Kawaji, Yuki; Tamura, Takashi; Itonaga, Masahiro; Yoshida, Takeichi; Maeda, Hiroki; Magari, Hirohito; Maekita, Takao; Iguchi, Mikitaka; Tamai, Hideyuki; Ichinose, Masao; Kato, Jun

2016-01-01

Background/Aims Transpapillary forceps biopsy is an effective diagnostic technique in patients with biliary stricture. This prospective study aimed to determine the usefulness of the wire-grasping method as a new technique for forceps biopsy. Methods Consecutive patients with biliary stricture or irregularities of the bile duct wall were randomly allocated to either the direct or wire-grasping method group. In the wire-grasping method, forceps in the duodenum grasps a guide-wire placed into the bile duct beforehand, and then, the forceps are pushed through the papilla without endoscopic sphincterotomy. In the direct method, forceps are directly pushed into the bile duct alongside a guide-wire. The primary endpoint was the success rate of obtaining specimens suitable for adequate pathological examination. Results In total, 32 patients were enrolled, and 28 (14 in each group) were eligible for analysis. The success rate was significantly higher using the wire-grasping method than the direct method (100% vs 50%, p=0.016). Sensitivity and accuracy for the diagnosis of cancer were comparable in patients with the successful procurement of biopsy specimens between the two methods (91% vs 83% and 93% vs 86%, respectively). Conclusions The wire-grasping method is useful for diagnosing patients with biliary stricture or irregularities of the bile duct wall. PMID:27021502

Computed Tomography Angiography Evaluation of Risk Factors for Unstable Intracranial Aneurysms.

PubMed

Wang, Guang-Xian; Gong, Ming-Fu; Wen, Li; Liu, Lan-Lan; Yin, Jin-Bo; Duan, Chun-Mei; Zhang, Dong

2018-03-19

To evaluate risk factors for instability in intracranial aneurysms (IAs) using computed tomography angiography (CTA). A total of 614 consecutive patients diagnosed with 661 IAs between August 2011 and February 2016 were reviewed. Patients and IAs were divided into stable and unstable groups. Along with clinical characteristics, IA characteristics were evaluated by CTA. Multiple logistic regression analysis was used to identify the independent risk factors associated with unstable IAs. Receiver operating characteristic (ROC) curve analysis was performed on the final model, and optimal thresholds were obtained. Patient age (odds ratio [OR], 0.946), cerebral atherosclerosis (CA; OR, 0.525), and IAs located at the middle cerebral artery (OR, 0.473) or internal carotid artery (OR, 0.512) were negatively correlated with instability, whereas IAs with irregular shape (OR, 2.157), deep depth (OR, 1.557), or large flow angle (FA; OR, 1.015) were more likely to be unstable. ROC analysis revealed threshold values of age, depth, and FA of 59.5 years, 4.25 mm, and 87.8°, respectively. The stability of IAs is significantly affected by several factors, including patient age and the presence of CA. IA shape and location also have an impact on the stability of IAs. Growth into an irregular shape, with a deep depth, and a large FA are risk factors for a change in IAs from stable to unstable. Copyright © 2018 Elsevier Inc. All rights reserved.

Quantitative morphometric analysis of hepatocellular carcinoma: development of a programmed algorithm and preliminary application.

PubMed

Yap, Felix Y; Bui, James T; Knuttinen, M Grace; Walzer, Natasha M; Cotler, Scott J; Owens, Charles A; Berkes, Jamie L; Gaba, Ron C

2013-01-01

The quantitative relationship between tumor morphology and malignant potential has not been explored in liver tumors. We designed a computer algorithm to analyze shape features of hepatocellular carcinoma (HCC) and tested feasibility of morphologic analysis. Cross-sectional images from 118 patients diagnosed with HCC between 2007 and 2010 were extracted at the widest index tumor diameter. The tumor margins were outlined, and point coordinates were input into a MATLAB (MathWorks Inc., Natick, Massachusetts, USA) algorithm. Twelve shape descriptors were calculated per tumor: the compactness, the mean radial distance (MRD), the RD standard deviation (RDSD), the RD area ratio (RDAR), the zero crossings, entropy, the mean Feret diameter (MFD), the Feret ratio, the convex hull area (CHA) and perimeter (CHP) ratios, the elliptic compactness (EC), and the elliptic irregularity (EI). The parameters were correlated with the levels of alpha-fetoprotein (AFP) as an indicator of tumor aggressiveness. The quantitative morphometric analysis was technically successful in all cases. The mean parameters were as follows: compactness 0.88±0.086, MRD 0.83±0.056, RDSD 0.087±0.037, RDAR 0.045±0.023, zero crossings 6±2.2, entropy 1.43±0.16, MFD 4.40±3.14 cm, Feret ratio 0.78±0.089, CHA 0.98±0.027, CHP 0.98±0.030, EC 0.95±0.043, and EI 0.95±0.023. MFD and RDAR provided the widest value range for the best shape discrimination. The larger tumors were less compact, more concave, and less ellipsoid than the smaller tumors (P < 0.0001). AFP-producing tumors displayed greater morphologic irregularity based on several parameters, including compactness, MRD, RDSD, RDAR, entropy, and EI (P < 0.05 for all). Computerized HCC image analysis using shape descriptors is technically feasible. Aggressively growing tumors have wider diameters and more irregular margins. Future studies will determine further clinical applications for this morphologic analysis.

Theory of HF induced turbulence in the ionosphere: Status and challenges

NASA Astrophysics Data System (ADS)

Dubois, D. F.

In the past five years the combination of new theoretical concepts and computer simulations along with dramatically improved observational diagnostics appear to have led to a detailed, quantitative, understanding of the properties of the Langmuir turbulence induced in the unpreconditioned ionosphere at Arecibo during the first tens of milliseconds following the turn-on of the HF heater. This is the only observational regime in which the initial ionospheric conditions are known to a high level of confidence. The so called strong Langmuir turbulence (SLT) theory predicts observed features in this early time heating which are completely at odds with the prediction of the traditional weak turbulence approximation. The understanding of the observed signatures for times greater than say 30-50 ms following the onset of heating at Arecibo is still incomplete. The same is apparently true for the observations at Tromso where the unique predictions of SLT theory are not so clearly observed. Density irregularities, induced by heating at Arecibo and perhaps present in the ambient ionosphere at Tromso, appear to control the properties of the turbulence. The proper description of the coexistence of Langmuir turbulence with various density irregularities and accounting for the turbulent modification of the electron velocity distribution are challenges for the theory. In this paper the author reviews, starting from the Vlasov-Poisson equations, the fundamental basis of the reduced models used to describe SLT and suggest improvements to the standard model including a new local quasi linear theory for the treatment of hot electron acceleration and transit time damping or burnout of collapsing Langmuir cavitons.

Description and correlation of reservoir heterogenity within the Big Injun sandstone, Granny Creek field, West Virginia

DOE Office of Scientific and Technical Information (OSTI.GOV)

Vargo, A.; McDowell, R.; Matchen, D.

1992-01-01

The Granny Creek field (approximately 6 sq. miles in area), located in Clay and Roane counties, West Virginia, produces oil from the Big Injun sandstone (Lower Mississippian). Analysis of 15 cores, 22 core analyses, and approximately 400 wireline logs (gamma ray and bulk density) show that the Big Injun (approximately 12 to 55 feet thick) can be separated into an upper, coarse-grained sandstone and a lower, fine-grained sandstone. The Big Injun is truncated by an erosional unconformity of Early to Middle Mississippian age which removes the coarse-grain upper unit in the northwest portion of the field. The cores show nodulesmore » and zones (1 inch to 6 feet thick) of calcite and siderite cement. Where the cements occur as zones, porosity and permeability are reduced. Thin shales (1 inch to 1 foot thick) are found in the coarse-grained member of the Big Injun, whereas the bottom of the fine-grained, lower member contains intertongues of dark shale which cause pinchouts in porosity at the bottom of the reservoir. Calcite and siderite cement are recognized on wireline logs as high bulk density zones that form horizontal, inclined, and irregular pods of impermeable sandstone. At a 400 foot well spacing, pods may be confined to a single well or encompass as many as 30 wells creating linear and irregular barriers to flow. These pods increase the length of the fluid flow path and may divide the reservoir into discrete compartments. The combination of sedimentologic and diagenetic features contribute to the heterogeneity observed in the field.« less

14 CFR 121.563 - Reporting mechanical irregularities.

Code of Federal Regulations, 2010 CFR

2010-01-01

... 14 Aeronautics and Space 3 2010-01-01 2010-01-01 false Reporting mechanical irregularities. 121.563 Section 121.563 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF... mechanical irregularities. The pilot in command shall ensure that all mechanical irregularities occurring...

Testing Of Choiced Ceramics Cutting Tools At Irregular Interrupted Cut

NASA Astrophysics Data System (ADS)

Kyncl, Ladislav; Malotová, Šárka; Nováček, Pavel; Nicielnik, Henryk; Šoková, Dagmar; Hemžský, Pavel; Pitela, David; Holubjak, Jozef

2015-12-01

This article discusses the test of removable ceramic cutting inserts during machining irregular interrupted cut. Tests were performed on a lathe, with the preparation which simulated us the interrupted cut. By changing the number of plates mounted in a preparation it simulate us a regular or irregular interrupted cut. When with four plates it was regular interrupted cut, the remaining three variants were already irregular cut. It was examined whether it will have the irregular interrupted cutting effect on the insert and possibly how it will change life of inserts during irregular interrupted cut (variable delay between shocks).

Compositions of Spherules and Rock Surfaces at Meridiani

NASA Technical Reports Server (NTRS)

Mittlefehldt, David W.; Jolliff, B. L.; Clark, B. C.; Gellert, R.

2007-01-01

The Alpha Particle X-ray Spectrometers (APXS) on the Mars Exploration Rovers (MER) have proven extremely valuable for analyzing rocks and soils on the surface of Mars. The precision of their compositional measurements has been shown to be phenomenal through analyses of the compositionally very uniform Meridiani soils. Through combined use of the rock abrasion tool (RAT) and the analytical instruments on the in-situ deployment device (IDD), analyses of the interiors of fine-grained and texturally uniform rocks with surfaces ground flat have been made under conditions that are nearly ideal for this mode of analysis. The APXS has also been used frequently to analyze materials whose characteristics, surface morphologies, and sample-detector geometries are less than ideal, but the analyses of which are nonetheless very useful for understanding the makeup of the target materials. Such targets include undisturbed rocks with irregular and sometimes coated surfaces and mixed targets such as soils that include fine-grained components as well as coarse grains and pieces of rocks. Such target materials include the well known hematite-rich concretions, referred to as blueberries because of their multispectral color, size, and mode of occurrence. In addition to non-ideal target geometry, such mixed materials also present a heterogeneous target in terms of density. These irregularities violate the assumptions commonly associated with analyses done in the laboratory to achieve the highest possible accuracy. Here we acknowledge the irregularities and we examine the inferences drawn from specific chemical trends obtained on imperfect targets in light of one of the potential pitfalls of natural materials on the surface of Mars, namely thin dust coatings.

Coordinated observations of postmidnight irregularities and thermospheric neutral winds and temperatures at low latitudes

NASA Astrophysics Data System (ADS)

Dao, Tam; Otsuka, Yuichi; Shiokawa, Kazuo; Nishioka, Michi; Yamamoto, Mamoru; Buhari, Suhaila M.; Abdullah, Mardina; Husin, Asnawi

2017-07-01

We investigated a postmidnight field-aligned irregularity (FAI) event observed with the Equatorial Atmosphere Radar at Kototabang (0.2°S, 100.3°E, dip latitude 10.4°S) in Indonesia on the night of 9 July 2010 using a comprehensive data set of both neutral and plasma parameters. We examined the rate of total electron content change index (ROTI) obtained from GPS receivers in Southeast Asia, airglow images detected by an all-sky imager, and thermospheric neutral winds and temperatures obtained by a Fabry-Perot interferometer at Kototabang. Altitudes of the F layer (h'F) observed by ionosondes at Kototabang, Chiang Mai, and Chumphon were also surveyed. We found that the postmidnight FAIs occurred within plasma bubbles and coincided with kilometer-scale plasma density irregularities. We also observed an enhancement of the magnetically equatorward thermospheric neutral wind at the same time as the increase of h'F at low-latitude stations, but h'F at a station near the magnetic equator remained invariant. Simultaneously, a magnetically equatorward gradient of thermospheric temperature was identified at Kototabang. The convergence of equatorward neutral winds from the Northern and Southern Hemispheres could be associated with a midnight temperature maximum occurring around the magnetic equator. Equatorward neutral winds can uplift the F layer at low latitudes and increase the growth rate of Rayleigh-Taylor instabilities, causing more rapid extension of plasma bubbles. The equatorward winds in both hemispheres also intensify the eastward Pedersen current, so a large polarization electric field generated in the plasma bubble might play an important role in the generation of postmidnight FAIs.

Corneal clouding in Alport syndrome.

PubMed

Herwig, Martina C; Eter, Nicole; Holz, Frank G; Loeffler, Karin U

2011-03-01

Alport syndrome is a hereditary basement membrane disease that typically involves the kidney, the cochlea, and the eyes. Characteristic ocular problems include posterior polymorphous corneal dystrophy, lenticonus, and dot-and-fleck retinopathy. A 48-year-old male patient with Alport syndrome presented with corneal and retinal changes. In 2003, he was diagnosed with posterior polymorphous corneal dystrophy and received a corneal transplant in his left eye in 2007 because of progressive deterioration in visual acuity. At this time, a lamellar macular hole was diagnosed in his right eye. The removed corneal button was examined by light and electron microscopy and by immunohistochemistry. Histology revealed not only endothelial changes but also a marked irregular thickening of the epithelial basement membrane and of Bowman layer. Alcian blue staining demonstrated an accumulation of mucopolysaccharides in the Bowman layer. The presented changes underline the great variation of ocular disorders related to Alport syndrome. To our knowledge, this is one of the first reports describing histologic corneal findings in Alport syndrome. Only a few cases with accumulation of mucopolysaccharides in the Bowman layer have been described previously, none of them being associated with Alport syndrome. Besides, anterior corneal alterations and corneal clouding seem to be uncommon in patients suffering from Alport syndrome.

Fine-needle aspiration of low-grade adenosquamous carcinomas of the breast: a report of three new cases.

PubMed

Bataillon, Guillaume; Collet, Jean-François; Voillemot, Nicole; Menet, Emmanuelle; Vincent-Salomon, Anne; Klijanienko, Jerzy

2014-01-01

To describe cytology patterns in low-grade adenosquamous carcinomas (LGASCs) of the breast. Low-grade adenosquamous carcinomas of the breast are a recently described rare variant of primary metaplastic carcinomas characterized by clinical indolence, slow evolution and excellent survival. To date, only 7 cases of LGASC were studied cytologically, and it was demonstrated that LGASC identification was difficult because its cellular components exhibited unspecific and nonsuspicious features. They consisted of irregularly clustered cells without prominent cytonuclear atypia, mitosis or necrosis. The presence of metaplastic cells or keratin debris was helpful in accurate tumor typing. We report here 3 additional cases of LGASC that were initially studied by fine-needle aspiration. We have also encountered diagnostic difficulties and misdiagnosed tumors, since 2 cases were underdiagnosed as 'suspicious' and only 1 was accurately diagnosed as malignancy. The review of our cases and the literature confirms that, despite its putative metaplastic origin, LGASC is an entity which is difficult to diagnose using classical cytological methods. Moreover, core-needle biopsy as well as frozen sections may also misdiagnose LGASC as a benign breast lesion. © 2014 S. Karger AG, Basel.

Generation of Artificial Ionospheric Irregularities in the Midlatitude Ionosphere Modified by High-Power High-Frequency X-Mode Radio Waves

NASA Astrophysics Data System (ADS)

Frolov, V. L.; Bolotin, I. A.; Komrakov, G. P.; Pershin, A. V.; Vertogradov, G. G.; Vertogradov, V. G.; Vertogradova, E. G.; Kunitsyn, V. E.; Padokhin, A. M.; Kurbatov, G. A.; Akchurin, A. D.; Zykov, E. Yu.

2014-11-01

We consider the properties of the artificial ionospheric irregularities excited in the ionospheric F 2 region modified by high-power high-frequency X-mode radio waves. It is shown that small-scale (decameter) irregularities are not generated in the midlatitude ionosphere. The intensity of irregularities with the scales l ⊥ ≈50 m to 3 km is severalfold weaker compared with the case where the irregularities are excited by high-power O-mode radio waves. The intensity of the larger-scale irregularities is even stronger attenuated. It is found that the generation of large-scale ( l ⊥ ≈5-10 km) artificial ionospheric irregularities is enhanced at the edge of the directivity pattern of a beam of high-power radio waves.

Spectral domain optical coherence tomography in Celestone® retinal toxicity.

PubMed

Marticorena-Álvarez, P; González Guijarro, J

2016-03-01

After inadvertent intravitreal injection of Celestone® (betamethasone sodium phosphate and acetate, benzalkonium chloride) in a patient, the macular spectral domain optical coherence tomography (SD-OCT) images showed hyper-reflectivity, thinning, and irregular spikes in the inner retinal layers. These early findings could explain the toxic secondary anatomical changes due to the drug itself and/or to its excipients. Late and permanent SD-OCT findings included changes in the ellipsoid zone and cystic-like spaces. In this case, SD-OCT images can help to better understand the pathophysiology of the retinal damage and to diagnose the associated complications, providing information with prognostic value. Copyright © 2015 Sociedad Española de Oftalmología. Published by Elsevier España, S.L.U. All rights reserved.

Why Irregulars Win: Asymmetry of Motivations and the Outcomes of Irregular Warfare

DTIC Science & Technology

2016-12-01

have on dependent variables.” 58 Alexander L. George and Andrew Bennett, Case Studies and Theory Development in the Social Sciences, BCSIA Studies in...of case studies is used to evaluate irregular wars and the motivations of the combatants. The findings suggest that asymmetries of motivation only...irregular wars. A mixed methodology, including heuristics, process tracing, and comparison of case studies is used to evaluate irregular wars and the

Observations of supra-arcade fans: instabilities at the head of reconnection jets

DOE Office of Scientific and Technical Information (OSTI.GOV)

Innes, D. E.; Guo, L.-J.; Schmit, D.

2014-11-20

Supra-arcade fans are bright, irregular regions of emission that develop during eruptive flares above flare arcades. The underlying flare arcades are thought to be a consequence of magnetic reconnection along a current sheet in the corona. At the same time, theory predicts plasma jets from the reconnection sites which are extremely difficult to observe directly because of their low densities. It has been suggested that the dark supra-arcade downflows (SADs) seen falling through supra-arcade fans may be low-density jet plasma. The head of a low-density jet directed toward higher-density plasma would be Rayleigh-Taylor unstable, and lead to the development ofmore » rapidly growing low- and high-density fingers along the interface. Using Solar Dynamics Observatory/Atmospheric Imaging Assembly 131 Å images, we show details of SADs seen from three different orientations with respect to the flare arcade and current sheet, and highlight features that have been previously unexplained, such as the splitting of SADs at their heads, but are a natural consequence of instabilities above the arcade. Comparison with three-dimensional magnetohydrodynamic simulations suggests that SADs are the result of secondary instabilities of the Rayleigh-Taylor type in the exhaust of reconnection jets.« less

Analysis of an Irregular RC Multi-storeyed Building Subjected to Dynamic Loading

NASA Astrophysics Data System (ADS)

AkashRaut; Pachpor, Prabodh; Dautkhani, Sanket

2018-03-01

Many buildings in the present scenario have irregular configurations both in plan and elevation. This in future may subject to devastating earthquakes. So it is necessary to analyze the structure. The present paper is made to study three type of irregularity wiz vertical, mass and plan irregularity as per clause 7.1 of IS 1893 (part1)2002 code. The paper discusses the analysis of RC (Reinforced Concrete) Buildings with vertical irregularity. The study as a whole makes an effort to evaluate the effect of vertical irregularity on RC buildings for which comparison of three parameters namely shear force, bending moment and deflection are taken into account.

The behaviour of platelets in natural diamonds and the development of a new mantle thermometer

NASA Astrophysics Data System (ADS)

Speich, L.; Kohn, S. C.; Bulanova, G. P.; Smith, C. B.

2018-05-01

Platelets are one of the most common defects occurring in natural diamonds but their behaviour has not previously been well understood. Recent technical advances, and a much improved understanding of the correct interpretation of the main infrared (IR) feature associated with platelets (Speich et al. 2017), facilitated a systematic study of platelets in 40 natural diamonds. Three different types of platelet behaviour were identified here. Regular diamonds show linear correlations between both B-centre concentrations and platelet density and also between platelet size and platelet density. Irregular diamonds display reduced platelet density due to platelet breakdown, anomalously large or small platelets and a larger platelet size distribution. These features are indicative of high mantle storage temperatures. Finally, a previously unreported category of subregular diamonds is defined. These diamonds experienced low mantle residence temperatures and show smaller than expected platelets. Combining the systematic variation in platelet density with temperatures of mantle storage, determined by nitrogen aggregation, we can demonstrate that platelet degradation proceeds at a predictable rate. Thus, in platelet-bearing diamonds where N aggregation is complete, an estimate of annealing temperature can now be made for the first time.

Scintillation Monitoring Using Asymmetry Index

NASA Astrophysics Data System (ADS)

Shaikh, Muhammad Mubasshir; Mahrous, Ayman; Abdallah, Amr; Notarpietro, Riccardo

Variation in electron density can have significant effect on GNSS signals in terms of propagation delay. Ionospheric scintillation can be caused by rapid change of such delay, specifically, when they last for a longer period of time. Ionospheric irregularities that account for scintillation may vary significantly in spatial range and drift with the background plasma at speeds of 45 to 130 m/sec. These patchy irregularities may occur several times during night, e.g. in equatorial region, with the patches move through the ray paths of the GNSS satellite signals. These irregularities are often characterized as either ‘large scale’ (which can be as large as several hundred km in East-West direction and many times that in the North-South direction) or ‘small scale’ (which can be as small as 1m). These small scale irregularities are regarded as the main cause of scintillation [1,2]. In normal solar activity conditions, the mid-latitude ionosphere is not much disturbed. However, during severe magnetic storms, the aurora oval extends towards the equator and the equator anomaly region may stretched towards poles extending the scintillation phenomena more typically associated with those regions into mid-latitudes. In such stormy conditions, the predicted TEC may deviate largely from the true value of the TEC both at low and mid-latitudes due to which GNSS applications may be strongly degraded. This work is an attempt to analyze ionospheric scintillation (S4 index) using ionospheric asymmetry index [3]. The asymmetry index is based on trans-ionospheric propagation between GPS and LEO satellites in a radio occultation (RO) scenario, using background ionospheric data provided by MIDAS [4]. We attempted to simulate one of the recent geomagnetic storms (NOAA scale G4) occurred over low/mid-latitudes. The storm started on 26 September 2011 at UT 18:00 and lasted until early hours of 27 September 2011. The scintillation data for the storm was taken from an ionospheric station in Cairo, Egypt (lat= 29.8641 °, long= 31.3172 °). It was observed that the level of asymmetry was significantly increased during the main phase of the geomagnetic storm. This was due to the changes in ionization, which in turn produced large gradients along occulted ray path in the ionosphere. A very good correlation was found between the evaluated ionospheric asymmetry index and the S4 scintillation index. Additionally, the correlation between evaluated ionospheric asymmetry and errors related to the RO inversion products such as peak electron density (delta NmF2) and Vertical TEC (delta VTEC) estimates also showed promising results. This work is carried out under the framework of the TRANSMIT project (Training Research and Applications Network to Support the Mitigation of Ionospheric Threats - www.transmit-ionosphere.net). [1]Basu Sa. and Basu Su., (1981), ‘Equatorial Scintillation - A Review’, Journal of Atmospheric and Solar-Terrestrial Physics, 43, p. 473. [2]Davies K., (1990), ‘Ionospheric Radio’, IEEE Electromagnetic Waves Series 31, Peter Peregrinus Ltd. [3]Spencer, P., Mitchell, C.N., (2007) ‘Imaging of fast moving electron-density structures in the polar cap’, Annals of Geophysics, vol. 50, no. 3, pp. 427-434. [4]Shaikh, M.M., Notarpietro, R., Nava, B., (2013) ‘The Impact of Spherical Symmetry Assumption on Radio Occultation Data Inversion in the Ionosphere: An Assessment Study’, Advances in Space Research, doi: http://dx.doi.org/10.1016/j.asr.2013.10.025.

Nonlinear effects of climate and density in the dynamics of a fluctuating population of reindeer.

PubMed

Tyler, Nicholas J C; Forchhammer, Mads C; Øritsland, Nils Are

2008-06-01

Nonlinear and irregular population dynamics may arise as a result of phase dependence and coexistence of multiple attractors. Here we explore effects of climate and density in the dynamics of a highly fluctuating population of wild reindeer (Rangifer tarandus platyrhynchus) on Svalbard observed over a period of 29 years. Time series analyses revealed that density dependence and the effects of local climate (measured as the degree of ablation [melting] of snow during winter) on numbers were both highly nonlinear: direct negative density dependence was found when the population was growing (Rt > 0) and during phases of the North Atlantic Oscillation (NAO) characterized by winters with generally high (1979-1995) and low (1996-2007) indices, respectively. A growth-phase-dependent model explained the dynamics of the population best and revealed the influence of density-independent processes on numbers that a linear autoregressive model missed altogether. In particular, the abundance of reindeer was enhanced by ablation during phases of growth (Rt > 0), an observation that contrasts with the view that periods of mild weather in winter are normally deleterious for reindeer owing to icing of the snowpack. Analyses of vital rates corroborated the nonlinearity described in the population time series and showed that both starvation mortality in winter and fecundity were nonlinearly related to fluctuations in density and the level of ablation. The erratic pattern of growth of the population of reindeer in Adventdalen seems, therefore, to result from a combination of the effects of nonlinear density dependence, strong density-dependent mortality, and variable density independence related to ablation in winter.

16 CFR 501.6 - Cellulose sponges, irregular dimensions.

Code of Federal Regulations, 2011 CFR

2011-01-01

... 16 Commercial Practices 1 2011-01-01 2011-01-01 false Cellulose sponges, irregular dimensions. 501... REQUIREMENTS AND PROHIBITIONS UNDER PART 500 § 501.6 Cellulose sponges, irregular dimensions. Variety packages of cellulose sponges of irregular dimensions, are exempted from the requirements of § 500.25 of this...

16 CFR 501.6 - Cellulose sponges, irregular dimensions.

Code of Federal Regulations, 2014 CFR

2014-01-01

... 16 Commercial Practices 1 2014-01-01 2014-01-01 false Cellulose sponges, irregular dimensions. 501... REQUIREMENTS AND PROHIBITIONS UNDER PART 500 § 501.6 Cellulose sponges, irregular dimensions. Variety packages of cellulose sponges of irregular dimensions, are exempted from the requirements of § 500.25 of this...

16 CFR 501.6 - Cellulose sponges, irregular dimensions.

Code of Federal Regulations, 2013 CFR

2013-01-01

... 16 Commercial Practices 1 2013-01-01 2013-01-01 false Cellulose sponges, irregular dimensions. 501... REQUIREMENTS AND PROHIBITIONS UNDER PART 500 § 501.6 Cellulose sponges, irregular dimensions. Variety packages of cellulose sponges of irregular dimensions, are exempted from the requirements of § 500.25 of this...

16 CFR 501.6 - Cellulose sponges, irregular dimensions.

Code of Federal Regulations, 2012 CFR

2012-01-01

... 16 Commercial Practices 1 2012-01-01 2012-01-01 false Cellulose sponges, irregular dimensions. 501... REQUIREMENTS AND PROHIBITIONS UNDER PART 500 § 501.6 Cellulose sponges, irregular dimensions. Variety packages of cellulose sponges of irregular dimensions, are exempted from the requirements of § 500.25 of this...

48 CFR 14.405 - Minor informalities or irregularities in bids.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 48 Federal Acquisition Regulations System 1 2010-10-01 2010-10-01 false Minor informalities or... Minor informalities or irregularities in bids. A minor informality or irregularity is one that is merely... cure any deficiency resulting from a minor informality or irregularity in a bid or waive the deficiency...

48 CFR 14.405 - Minor informalities or irregularities in bids.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 48 Federal Acquisition Regulations System 1 2011-10-01 2011-10-01 false Minor informalities or... Minor informalities or irregularities in bids. A minor informality or irregularity is one that is merely... cure any deficiency resulting from a minor informality or irregularity in a bid or waive the deficiency...

16 CFR 501.6 - Cellulose sponges, irregular dimensions.

Code of Federal Regulations, 2010 CFR

2010-01-01

... 16 Commercial Practices 1 2010-01-01 2010-01-01 false Cellulose sponges, irregular dimensions. 501... REQUIREMENTS AND PROHIBITIONS UNDER PART 500 § 501.6 Cellulose sponges, irregular dimensions. Variety packages of cellulose sponges of irregular dimensions, are exempted from the requirements of § 500.25 of this...

Theories of High Latitude Ionospheric Irregularities: A Review.

DTIC Science & Technology

1982-11-17

i or e) is the species density and E ic the total electric field. Since we will be interested in low frequencies and long wavelenghts , we have...5) by separating n - n (y) + 6n with 6n, 6+ a exp [i(kx + kz - wt)], w + iy, L (1/n )(an o/y). This gives a growth rate v . Vin cE0 B evd)] (6) 𔃼 in...34eai) + (kz2/k12 ))J]. (I denotes along z). The expression for the growth rate y in (6) can be maximized as a function of e - k /k , a measure of field

Study of Track Irregularity Time Series Calibration and Variation Pattern at Unit Section

PubMed Central

Jia, Chaolong; Wei, Lili; Wang, Hanning; Yang, Jiulin

2014-01-01

Focusing on problems existing in track irregularity time series data quality, this paper first presents abnormal data identification, data offset correction algorithm, local outlier data identification, and noise cancellation algorithms. And then proposes track irregularity time series decomposition and reconstruction through the wavelet decomposition and reconstruction approach. Finally, the patterns and features of track irregularity standard deviation data sequence in unit sections are studied, and the changing trend of track irregularity time series is discovered and described. PMID:25435869

Spectral element modelling of fault-plane reflections arising from fluid pressure distributions

USGS Publications Warehouse

Haney, M.; Snieder, R.; Ampuero, J.-P.; Hofmann, R.

2007-01-01

The presence of fault-plane reflections in seismic images, besides indicating the locations of faults, offers a possible source of information on the properties of these poorly understood zones. To better understand the physical mechanism giving rise to fault-plane reflections in compacting sedimentary basins, we numerically model the full elastic wavefield via the spectral element method (SEM) for several different fault models. Using well log data from the South Eugene Island field, offshore Louisiana, we derive empirical relationships between the elastic parameters (e.g. P-wave velocity and density) and the effective-stress along both normal compaction and unloading paths. These empirical relationships guide the numerical modelling and allow the investigation of how differences in fluid pressure modify the elastic wavefield. We choose to simulate the elastic wave equation via SEM since irregular model geometries can be accommodated and slip boundary conditions at an interface, such as a fault or fracture, are implemented naturally. The method we employ for including a slip interface retains the desirable qualities of SEM in that it is explicit in time and, therefore, does not require the inversion of a large matrix. We performa complete numerical study by forward modelling seismic shot gathers over a faulted earth model using SEM followed by seismic processing of the simulated data. With this procedure, we construct post-stack time-migrated images of the kind that are routinely interpreted in the seismic exploration industry. We dip filter the seismic images to highlight the fault-plane reflections prior to making amplitude maps along the fault plane. With these amplitude maps, we compare the reflectivity from the different fault models to diagnose which physical mechanism contributes most to observed fault reflectivity. To lend physical meaning to the properties of a locally weak fault zone characterized as a slip interface, we propose an equivalent-layer model under the assumption of weak scattering. This allows us to use the empirical relationships between density, velocity and effective stress from the South Eugene Island field to relate a slip interface to an amount of excess pore-pressure in a fault zone. ?? 2007 The Authors Journal compilation ?? 2007 RAS.

Reduced bone mineral density in adult women diagnosed with menstrual disorders during adolescence.

PubMed

Wiksten-Almströmer, Marianne; Hirschberg, Angelica Lindën; Hagenfeldt, Kerstin

2009-01-01

To evaluate the long-term effects on bone mineral density (BMD) in women diagnosed with menstrual disorders in their adolescence. Prospective follow-up study six years after the initial investigation. A youth clinic that is part of the school health system in Stockholm. Eighty-seven women diagnosed with secondary amenorrhea or oligomenorrhea in adolescence. Subjects underwent gynecological examination, evaluation of eating behavior and physical activity. Whole body Dual Energy X-ray Absorptiometry was used for measurement of BMD. BMD. The overall frequency of osteopenia/osteoporosis was 52%, and three girls had osteoporosis. Women with previous secondary amenorrhea had significantly lower BMD in the pelvis and lumbar spine than those with previous oligomenorrhea. The strongest predictor of low BMD was a restrictive eating disorder in adolescence and the most important counteraction was high physical activity at follow-up and a body mass index (BMI) > or = 22. Persistent menstrual dysfunction at follow-up was associated with polycystic ovary syndrome and lower frequency of osteopenia. This clinical follow-up study has demonstrated a high frequency of osteopenia in women diagnosed with menstrual disorders in adolescence. Previous anorectic behavior was the strongest negative predictor of BMD. It is important to pay attention to an underlying eating disorder in young women with menstrual dysfunction in order to promote bone health.

Computed tomography as an aid in the diagnosis of chronic nasal disease in dogs.

PubMed

Lefebvre, J; Kuehn, N F; Wortinger, A

2005-06-01

To assess the use of computed tomography (CT) in the diagnosis of chronic nasal disease in dogs. A retrospective study of 85 dogs with chronic nasal discharge due to primary nasal disease, which had undergone nasal CT and biopsy, was carried out. Medical records were reviewed for signalment, clinical signs, CT findings, endoscopic findings and histopathology. The results obtained via CT were correlated with nasal histopathology and gross anatomical observations were recorded at the time of rhinoscopy. Neoplasia was diagnosed in 37 dogs for which CT typically revealed a soft tissue density associated with extensive turbinate destruction. Inflammatory rhinitis was diagnosed in 40 dogs. CT disclosed either normal turbinate structures or mild to moderate turbinate destruction, with or without the presence of soft tissue densities (mucopus) within the nasal passages. Fungal rhinitis was diagnosed in seven dogs for which CT disclosed extensive turbinate destruction with hyperlucency of the nasal passages. One dog had normal CT and histopathology findings. CT greatly enhanced the ability to diagnose chronic nasal disease in dogs, providing detailed Information regarding the extent of the disease, accurate discrimination of neoplastic versus non-neoplastic diseases, and identification of areas of the nose to examine rhinoscopically and suspicious regions to target for biopsy.

Reacting to 'Irregular' Learning Environments in a Senior Secondary School

ERIC Educational Resources Information Center

Alterator, Scott; Deed, Craig

2016-01-01

Modern school design continues to incorporate openness and irregularity as a means of achieving improvement. Irregular learning environments can act as a catalyst for student unsettling and enable possibilities of teacher practice. We outline a case study of teacher adaptation to irregular environments in a senior school setting. We argue that…

Clinical features of subepithelial layer irregularities of cornea.

PubMed

Lee, Yong Woo; Gye, Hyo Jung; Choi, Chul Young

2015-07-01

To illustrate surgical outcomes of subepithelial irregularities that were identified incidentally during laser refractive surgery. The study group consisted of 406 patients who underwent 787 surface ablation refractive surgeries. Ophthalmologic evaluations were performed before each procedure and at 1, 3 and 6 months post-operatively. Subepithelial irregularities were evaluated by analyzing still photographs captured from video recordings. Sizes and locations were determined by a calibrated scale located at the major axis of the tracking system's reticle. Subepithelial irregularities were identified in 27 eyes during 787 surface ablation refractive surgeries. Most of the subepithelial irregularities did not show any abnormalities in the wavefront aberrometer. However, one case with diameter greater than 1.00 mm and one case of clustered multiple subepithelial irregularities with moderate size were corresponded significant coma (Z31) and increased higher order aberration (HOA) in the HOA gradient map. Corneal subepithelial irregularities may be related to problems that include significantly increased localized HOA and remaining permanent subepithelial opacity. Subepithelial irregularity should be considered even if the surface of the cornea is intact and there are no specific findings measured by corneal topography.

Capture of irregular satellites at Jupiter

DOE Office of Scientific and Technical Information (OSTI.GOV)

Nesvorný, David; Vokrouhlický, David; Deienno, Rogerio

The irregular satellites of outer planets are thought to have been captured from heliocentric orbits. The exact nature of the capture process, however, remains uncertain. We examine the possibility that irregular satellites were captured from the planetesimal disk during the early solar system instability when encounters between the outer planets occurred. Nesvorný et al. already showed that the irregular satellites of Saturn, Uranus, and Neptune were plausibly captured during planetary encounters. Here we find that the current instability models present favorable conditions for capture of irregular satellites at Jupiter as well, mainly because Jupiter undergoes a phase of close encountersmore » with an ice giant. We show that the orbital distribution of bodies captured during planetary encounters provides a good match to the observed distribution of irregular satellites at Jupiter. The capture efficiency for each particle in the original transplanetary disk is found to be (1.3-3.6) × 10{sup –8}. This is roughly enough to explain the observed population of jovian irregular moons. We also confirm Nesvorný et al.'s results for the irregular satellites of Saturn, Uranus, and Neptune.« less

New Features of Electrocardiogram in a Case Report of Arrhythmogenic Right Ventricular Cardiomyopathy: A Care-Compliant Article.

PubMed

Pei, Haifeng; Yu, Qiujun; Su, Xiaohua; Wang, Zhen; Zhao, Heng; Yang, Dachun; Yang, Yongjian; Li, De

2016-04-01

Arrhythmogenic right ventricular cardiomyopathy (ARVC) is a crucial health problem. With sudden death often being the first presentation, early diagnosis for ARVC is essential. Up to date, electrocardiogram (ECG) is a widely used diagnostic method without invasive harms. To diagnose and treat ARVC as well as possible, we should clearly elucidate its pathophysiological alterations. A 66-year-old farmer presented to the Emergency Department with continuous palpitation, chest tightness, profuse sweating, and nausea with no obvious predisposing causes. An ECG indicated ventricular tachycardia (VT). The patient experienced a sudden drop in blood pressure and acute confusion. After an immediate electrical conversion, his consciousness was gradually restored, and symptoms relieved. The patient was then transferred to the Department of Cardiology to receive ECG, echocardiography, coronary angiogram, biochemical assays, endocardiac tracing, and radiofrequency ablation. In the end, he was diagnosed with ARVC, evidenced by bilateral ventricle dilation and epsilon waves in leads V1-V3. Appropriate therapies were provided for this patient including pharmacological intervention and radiofrequency ablation. Although the diagnosis of ARVC is not difficult, this patient's ECG manifested several interesting features and should be further investigated: T wave inversions were found extensively in the anterior and inferior leads, revealing the involvement of bilateral ventricles; VTs with different morphologies and cycle lengths were found, and some VTs manifested the feature of irregularly irregular rhythm, reminding us to carefully differentiate some special VTs from atrial fibrillation (AF); and epsilon waves gradually appeared in leads V1-V3 and avR since the onset of ARVC. Most importantly, the epsilon waves behind QRS complex appeared in both sinus rhythm and ventricular premature beats/VT originating from cardiac apex, whereas the epsilon waves prior to QRS complex occurred in VT originating from right ventricular outflow tract (RVOT). The features of T wave inversion and epsilon wave in ECGs and the appearance of VTs with different morphologies can reflect the progression of ARVC. The position relationship between epsilon wave and QRS complex in VT depends on ventricular activation sequence, that is, the localization of epsilon wave depends on where VT is originating from.

Diagnosing the Fine Structure of Electron Energy Within the ECRIT Ion Source

NASA Astrophysics Data System (ADS)

Jin, Yizhou; Yang, Juan; Tang, Mingjie; Luo, Litao; Feng, Bingbing

2016-07-01

The ion source of the electron cyclotron resonance ion thruster (ECRIT) extracts ions from its ECR plasma to generate thrust, and has the property of low gas consumption (2 sccm, standard-state cubic centimeter per minute) and high durability. Due to the indispensable effects of the primary electron in gas discharge, it is important to experimentally clarify the electron energy structure within the ion source of the ECRIT through analyzing the electron energy distribution function (EEDF) of the plasma inside the thruster. In this article the Langmuir probe diagnosing method was used to diagnose the EEDF, from which the effective electron temperature, plasma density and the electron energy probability function (EEPF) were deduced. The experimental results show that the magnetic field influences the curves of EEDF and EEPF and make the effective plasma parameter nonuniform. The diagnosed electron temperature and density from sample points increased from 4 eV/2×1016 m-3 to 10 eV/4×1016 m-3 with increasing distances from both the axis and the screen grid of the ion source. Electron temperature and density peaking near the wall coincided with the discharge process. However, a double Maxwellian electron distribution was unexpectedly observed at the position near the axis of the ion source and about 30 mm from the screen grid. Besides, the double Maxwellian electron distribution was more likely to emerge at high power and a low gas flow rate. These phenomena were believed to relate to the arrangements of the gas inlets and the magnetic field where the double Maxwellian electron distribution exits. The results of this research may enhance the understanding of the plasma generation process in the ion source of this type and help to improve its performance. supported by National Natural Science Foundation of China (No. 11475137)

Triglyceride to high-density lipoprotein cholesterol ratio and carotid intima-medial thickness in Chinese adolescents with newly diagnosed type 2 diabetes mellitus.

PubMed

Li, Xin; Deng, You-Ping; Yang, Miao; Wu, Yu-Wen; Sun, Su-Xin; Sun, Jia-Zhong

2016-03-01

To investigate the relationship between triglyceride to high-density lipoprotein cholesterol (TG/HDL-C) ratio and carotid intima-medial thickness (CIMT) in Chinese youth and adolescents with newly diagnosed type 2 diabetes mellitus (T2DM). Ninety-eight subjects aged 10-24 yr with newly-diagnosed T2DM had general inflammation, anthropometric, laboratory and CIMT data collected, and were divided into three groups based on TG/HDL-C tertiles. There were no significant differences in gender, age, fasting plasma glucose (FPG), hemoglobin A1c (HbA1c), and carotid arterial diameter (CAD) among the groups based on TG/HDL-C tertiles. Across TG/HDL-C tertiles, there was a significant progressive increase in body mass index (BMI), systolic blood pressure (SBP), diastolic blood pressure (DBP), homeostasis model assessment-estimated insulin resistance (HOMA-IR), TG, total cholesterol (TC), low-density lipoprotein-cholesterol (LDL-C) and CIMT (all P < 0.01 or P < 0.05), while HDL-C was decreased significantly across the groups (P < 0.01). In general linear regression model, TG/HDL-C was an independent determinant of CIMT even after adjusting for BMI, SBP, DBP, TG, TC, LDL-C, HDL-C, HbA1c and HOMA-IR. TG/HDL-C ratio, the marker of small dense LDL particles, is an independent determinant of CIMT in Chinese youth and adolescents with newly diagnosed T2DM, and may be a simple and helpful tool in predicting the increased CIMT in such patients. © 2015 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Medicine is not science: guessing the future, predicting the past.

PubMed

Miller, Clifford

2014-12-01

Irregularity limits human ability to know, understand and predict. A better understanding of irregularity may improve the reliability of knowledge. Irregularity and its consequences for knowledge are considered. Reliable predictive empirical knowledge of the physical world has always been obtained by observation of regularities, without needing science or theory. Prediction from observational knowledge can remain reliable despite some theories based on it proving false. A naïve theory of irregularity is outlined. Reducing irregularity and/or increasing regularity can increase the reliability of knowledge. Beyond long experience and specialization, improvements include implementing supporting knowledge systems of libraries of appropriately classified prior cases and clinical histories and education about expertise, intuition and professional judgement. A consequence of irregularity and complexity is that classical reductionist science cannot provide reliable predictions of the behaviour of complex systems found in nature, including of the human body. Expertise, expert judgement and their exercise appear overarching. Diagnosis involves predicting the past will recur in the current patient applying expertise and intuition from knowledge and experience of previous cases and probabilistic medical theory. Treatment decisions are an educated guess about the future (prognosis). Benefits of the improvements suggested here are likely in fields where paucity of feedback for practitioners limits development of reliable expert diagnostic intuition. Further analysis, definition and classification of irregularity is appropriate. Observing and recording irregularities are initial steps in developing irregularity theory to improve the reliability and extent of knowledge, albeit some forms of irregularity present inherent difficulties. © 2014 John Wiley & Sons, Ltd.

Preliminary Analysis of AIS Spectral Data Acquired from Semi-arid Shrub Communities in the Owens Valley, California

NASA Technical Reports Server (NTRS)

Ustin, S. L.; Rock, B. N.

1985-01-01

Spectral characteristics of semic-arid plant communities using 128 channel airborne imaging spectrometer (AIS) data acquired on October 30, 1984. Both field and AIS spectra of vegetation were relatively featureless and differed from substrate spectra primarily in albedo. Unvegetated sand dunes were examined to assess spectral variation resulting from topographic irregularity. Although shrub cover as low as 10% could be detected on relatively flat surfaces, such differences were obscured in more heterogeneous terrain. Sagebrush-covered fans which had been scarred by fire were studied to determine the effect of changes in plant density on reflectance. Despite noise in the atmospherically corrected spectra, these provide better resolution of differences in plant density than spectra which are solar-corrected only. A high negative correlation was found between reflectance and plant cover in areas which had uniform substrates and vegetation types. A lower correlation was found where vegetation and substrates were more diverse.

Midlatitude sporadic-E layers

NASA Technical Reports Server (NTRS)

Miller, K. L.; Smith, L. G.

1976-01-01

The partially transparent echo from midlatitude sporadic E layers was recorded by ionosondes between the blanketing frequency and the maximum frequency. The theory that the midlatitude sporadic E layers are not uniform in the horizontal plane but contain localized regions of high electron density was evaluated using data obtained by incoherent scatter radar and found to provide a satisfactory explanation. The main features of midlatitude sporadic E layers are consistent with the convergence of metallic ions as described by the wind shear theory applied to gravity waves and tides. The interference of gravity waves with other gravity waves and tides can be recognized in the altitudes of occurrence and the structure of the layers. Small scale horizontal irregularities are attributed in some cases to critical level effects and in others to fluid instabilities. The convergence of a meteor trail can, under some circumstances, account for localized enhancement of the electron density in the layer.

Global Variation of Meteor Trail Plasma Turbulence

NASA Technical Reports Server (NTRS)

Dyrud, L. P.; Hinrichs, J.; Urbina, J.

2011-01-01

We present the first global simulations on the occurrence of meteor trail plasma irregularities. These results seek to answer the following questions: when a meteoroid disintegrates in the atmosphere will the resulting trail become plasma turbulent, what are the factors influencing the development of turbulence, and how do they vary on a global scale. Understanding meteor trail plasma turbulence is important because turbulent meteor trails are visible as non-specular trails to coherent radars, and turbulence influences the evolution of specular radar meteor trails, particularly regarding the inference of mesospheric temperatures from trail diffusion rates, and their usage for meteor burst communication. We provide evidence of the significant effect that neutral atmospheric winds and density, and ionospheric plasma density have on the variability of meteor trail evolution and the observation of nonspecular meteor trails, and demonstrate that trails are far less likely to become and remain turbulent in daylight, explaining several observational trends using non-specular and specular meteor trails.

Environmental determinants of celeration behaviour.

PubMed

af Wåhlberg, Anders E

2015-01-01

Celeration (speed change) behaviour of drivers has been posited to be the best predictor of their traffic accident involvement. The origins of this behaviour, however, have not been specified. A model is therefore introduced, where celeration is partly due to the individual disposition of the driver (i.e., driving style), and partly to the environment (road layout, rules and traffic density). Three measurement problems for celeration were studied; the effect of traffic density, of regular versus irregular routes, and weight of the vehicle (loaded/unloaded) on celeration behaviour. Two small samples of truck drivers in Sweden were measured for several months each. There was a strong effect of vehicle load, with behaviour being more cautious with increased weight. Driving on different roads also yielded differences in behaviour, although the design used did not permit conclusions about what caused these. Traffic volume was not found to have any reliable effect on celeration.

Lunar dust simulant charging and transport under UV irradiation in vacuum: Experiments and numerical modeling

NASA Astrophysics Data System (ADS)

Champlain, A.; Matéo-Vélez, J.-C.; Roussel, J.-F.; Hess, S.; Sarrailh, P.; Murat, G.; Chardon, J.-P.; Gajan, A.

2016-01-01

Recent high-altitude observations, made by the Lunar Dust Experiment (LDEX) experiment on board LADEE orbiting the Moon, indicate that high-altitude (>10 km) dust particle densities are well correlated with interplanetary dust impacts. They show no evidence of high dust density suggested by Apollo 15 and 17 observations and possibly explained by electrostatic forces imposed by the plasma environment and photon irradiation. This paper deals with near-surface conditions below the domain of observation of LDEX where electrostatic forces could clearly be at play. The upper and lower limits of the cohesive force between dusts are obtained by comparing experiments and numerical simulations of dust charging under ultraviolet irradiation in the presence of an electric field and mechanical vibrations. It is suggested that dust ejection by electrostatic forces is made possible by microscopic-scale amplifications due to soil irregularities. At low altitude, this process may be complementary to interplanetary dust impacts.

New Frontiers in the Treatment of Diabetic Dyslipidemia

PubMed Central

Wang, Shu-Yi; Hsieh, Ming-Chia; Tu, Shih-Te; Chuang, Chieh-Sen

2013-01-01

Dyslipidemia is a major risk factor for cardiovascular complications in people with diabetes. Lowering low-density lipoprotein cholesterol (LDL-C) levels is effective in the primary and secondary prevention of diabetic vascular complications. However, LDL-C levels do not reflect all aspects of diabetic dyslipidemia, which is characterized by hypertriglyceridemia and low high-density lipoprotein cholesterol (HDL-C). Statins, nicotinic acid, and fibrates play a role in treating diabetic dyslipidemia. Atherosclerosis is a major disorder of the blood vessel wall in patients with diabetes. A number of antihyperlipidemic agents may be beneficial and exhibit effects at the actual site of vascular disease and not only on plasma lipoprotein concentrations. Several novel therapeutic compounds are currently being developed. These include additional therapeutics for LDL-C, triglycerides, HDL-C, and modulators of inflammation that can be used as possible synergic agents for the treatment of atherosclerosis and irregularities in plasma lipoprotein concentrations. PMID:24380093

Bone Health in Adolescent Athletes with a Focus on Female Athlete Triad

PubMed Central

Ackerman, Kathryn E.; Misra, Madhusmita

2013-01-01

Peak bone mass (PBM) is a negative predictor of osteoporosis and life-long fracture risk. Because osteoporosis is such a prevalent disease with life-threatening consequences later in life, it is important to try to maximize PBM. Adolescence is a critical time for bone acquisition. This review discusses some of the differences in male and female skeletal development and modifiable factors that enhance bone accrual in this age group, particularly in athletes. Hormonal influences, physical activity effects, and nutritional contributions are presented, with a focus on the adolescent athlete. Emphasis is placed on the importance of appropriate energy availability in this age group. The Female Athlete Triad (the inter-relationship of decreased energy availability, menstrual irregularity, and low bone density) is an important issue for adolescent, athletic women, and is therefore reviewed, including prevention and treatment strategies. Recommendations for maximizing bone density in both male and female adolescents are discussed. PMID:21378496

Effects of an irregular bedtime schedule on sleep quality, daytime sleepiness, and fatigue among university students in Taiwan.

PubMed

Kang, Jiunn-Horng; Chen, Shih-Ching

2009-07-19

An irregular bedtime schedule is a prevalent problem in young adults, and could be a factor detrimentally affecting sleep quality. The goal of the present study was to explore the association between an irregular bedtime schedule and sleep quality, daytime sleepiness, and fatigue among undergraduate students in Taiwan. A total of 160 students underwent a semi-structured interview and completed a survey comprising 4 parts: Pittsburgh Sleep Quality Index (PSQI), Epworth Sleepiness Scale (ESS), Fatigue Severity Scale (FSS), and a rating of irregular bedtime frequency. Participants were grouped into 3 groups in terms of irregular bedtime frequency: low, intermediate, or high according to their 2-week sleep log. To screen for psychological disorders or distress that may have affected responses on the sleep assessment measures, the Chinese health questionnaire-12 (CHQ-12) was also administered. We found an increase in bedtime schedule irregularity to be significantly associated with a decrease in average sleep time per day (Spearman r = -0.22, p = 0.05). Multivariate regression analysis revealed that irregular bedtime frequency and average sleep time per day were correlated with PSQI scores, but not with ESS or FSS scores. A significant positive correlation between irregular bedtime frequency and PSQI scores was evident in the intermediate (partial r = 0.18, p = 0.02) and high (partial r = 0.15, p = 0.05) frequency groups as compared to low frequency group. The results of our study suggest a high prevalence of both an irregular bedtime schedule and insufficient sleep among university students in Taiwan. Students with an irregular bedtime schedule may experience poor sleep quality. We suggest further research that explores the mechanisms involved in an irregular bedtime schedule and the effectiveness of interventions for improving this condition.

New Opportunities for Remote Sensing Ionospheric Irregularities by Fitting Scintillation Spectra

NASA Astrophysics Data System (ADS)

Carrano, C. S.; Rino, C. L.; Groves, K. M.

2017-12-01

In a recent paper, we presented a phase screen theory for the spectrum of intensity scintillations when the refractive index irregularities follow a two-component power law [Carrano and Rino, DOI: 10.1002/2015RS005903]. More recently we have investigated the inverse problem, whereby phase screen parameters are inferred from scintillation time series. This is accomplished by fitting the spectrum of intensity fluctuations with a parametrized theoretical model using Maximum Likelihood (ML) methods. The Markov-Chain Monte-Carlo technique provides a-posteriori errors and confidence intervals. The Akaike Information Criterion (AIC) provides justification for the use of one- or two-component irregularity models. We refer to this fitting as Irregularity Parameter Estimation (IPE) since it provides a statistical description of the irregularities from the scintillations they produce. In this talk, we explore some new opportunities for remote sensing ionospheric irregularities afforded by IPE. Statistical characterization of irregularities and the plasma bubbles in which they are embedded provides insight into the development of the underlying instability. In a companion paper by Rino et al., IPE is used to interpret scintillation due to simulated EPB structure. IPE can be used to reconcile multi-frequency scintillation observations and to construct high fidelity scintillation simulation tools. In space-to-ground propagation scenarios, for which an estimate of the distance to the scattering region is available a-priori, IPE enables retrieval of zonal irregularity drift. In radio occultation scenarios, the distance to the irregularities is generally unknown but IPE enables retrieval of Fresnel frequency. A geometric model for the effective scan velocity maps Fresnel frequency to Fresnel scale, yielding the distance to the irregularities. We demonstrate this approach by geolocating irregularities observed by the CORISS instrument onboard the C/NOFS satellite.

Models of utricular bouton afferents: role of afferent-hair cell connectivity in determining spike train regularity.

PubMed

Holmes, William R; Huwe, Janice A; Williams, Barbara; Rowe, Michael H; Peterson, Ellengene H

2017-05-01

Vestibular bouton afferent terminals in turtle utricle can be categorized into four types depending on their location and terminal arbor structure: lateral extrastriolar (LES), striolar, juxtastriolar, and medial extrastriolar (MES). The terminal arbors of these afferents differ in surface area, total length, collecting area, number of boutons, number of bouton contacts per hair cell, and axon diameter (Huwe JA, Logan CJ, Williams B, Rowe MH, Peterson EH. J Neurophysiol 113: 2420-2433, 2015). To understand how differences in terminal morphology and the resulting hair cell inputs might affect afferent response properties, we modeled representative afferents from each region, using reconstructed bouton afferents. Collecting area and hair cell density were used to estimate hair cell-to-afferent convergence. Nonmorphological features were held constant to isolate effects of afferent structure and connectivity. The models suggest that all four bouton afferent types are electrotonically compact and that excitatory postsynaptic potentials are two to four times larger in MES afferents than in other afferents, making MES afferents more responsive to low input levels. The models also predict that MES and LES terminal structures permit higher spontaneous firing rates than those in striola and juxtastriola. We found that differences in spike train regularity are not a consequence of differences in peripheral terminal structure, per se, but that a higher proportion of multiple contacts between afferents and individual hair cells increases afferent firing irregularity. The prediction that afferents having primarily one bouton contact per hair cell will fire more regularly than afferents making multiple bouton contacts per hair cell has implications for spike train regularity in dimorphic and calyx afferents. NEW & NOTEWORTHY Bouton afferents in different regions of turtle utricle have very different morphologies and afferent-hair cell connectivities. Highly detailed computational modeling provides insights into how morphology impacts excitability and also reveals a new explanation for spike train irregularity based on relative numbers of multiple bouton contacts per hair cell. This mechanism is independent of other proposed mechanisms for spike train irregularity based on ionic conductances and can explain irregularity in dimorphic units and calyx endings. Copyright © 2017 the American Physiological Society.

Ionospheric Coherence Bandwidth Measurements in the Lower VHF Frequency Range

NASA Astrophysics Data System (ADS)

Suszcynsky, D. M.; Light, M. E.; Pigue, M. J.

2015-12-01

The United States Department of Energy's Radio Frequency Propagation (RFProp) experiment consists of a satellite-based radio receiver suite to study various aspects of trans-ionospheric signal propagation and detection in four frequency bands, 2 - 55 MHz, 125 - 175 MHz, 365 - 415 MHz and 820 - 1100 MHz. In this paper, we present simultaneous ionospheric coherence bandwidth and S4 scintillation index measurements in the 32 - 44 MHz frequency range collected during the ESCINT equatorial scintillation experiment. 40-MHz continuous wave (CW) and 32 - 44 MHz swept frequency signals were transmitted simultaneously to the RFProp receiver suite from the Reagan Test Site at Kwajalein Atoll in the Marshall Islands (8.7° N, 167.7° E) in three separate campaigns during the 2014 and 2015 equinoxes. Results show coherence bandwidths as small as ~ 1 kHz for strong scintillation (S4 > 0.7) and indicate a high degree of ionospheric variability and irregularity on 10-m spatial scales. Spread-Doppler clutter effects arising from preferential ray paths to the satellite due to refraction off of isolated density irregularities are also observed and are dominant at low elevation angles. The results are compared to previous measurements and available scaling laws.

On the optimization of mitred overlaps in transformer cores

NASA Astrophysics Data System (ADS)

Bengtsson, C.; Pfützner, H.; Schönhuber, P.

1989-05-01

The influence of the overlap length a on the no-load loss P and excitation power S of single phase model cores was measured for different sheet widths w. It was found that the optimum overlap length a0 shows a non-linear increase with w. The appearance of such minima, however, was irregular, and in many cases, the lowest no-load loss was obtained at the smallest investigated overlap length, an effect which may result from the assembling conditions. Minima in P will appear as a consequence of a balance between loss contributions resulting from normal flux in the overlap region, from increased longitudinal flux due to flux transfer between sheets, and from the triangular cut-outs at the inner corners of the cores. However, the dependence of a0 on w is attributed only to the triangular cut-outs. The flatness of the minima in combination with their irregular appearance, makes the effect difficult to be used in practice. It is concluded that in power transformers, the overlap length should be chosen as small as possible within the limitations set by stability requirements of the core. This is especially important in cores with a high operating flux density.

Improving the surface metrology accuracy of optical profilers by using multiple measurements

NASA Astrophysics Data System (ADS)

Xu, Xudong; Huang, Qiushi; Shen, Zhengxiang; Wang, Zhanshan

2016-10-01

The performance of high-resolution optical systems is affected by small angle scattering at the mid-spatial-frequency irregularities of the optical surface. Characterizing these irregularities is, therefore, important. However, surface measurements obtained with optical profilers are influenced by additive white noise, as indicated by the heavy-tail effect observable on their power spectral density (PSD). A multiple-measurement method is used to reduce the effects of white noise by averaging individual measurements. The intensity of white noise is determined using a model based on the theoretical PSD of fractal surface measurements with additive white noise. The intensity of white noise decreases as the number of times of multiple measurements increases. Using multiple measurements also increases the highest observed spatial frequency; this increase is derived and calculated. Additionally, the accuracy obtained using multiple measurements is carefully studied, with the analysis of both the residual reference error after calibration, and the random errors appearing in the range of measured spatial frequencies. The resulting insights on the effects of white noise in optical profiler measurements and the methods to mitigate them may prove invaluable to improve the quality of surface metrology with optical profilers.

Chemical evolution in spiral and irregular galaxies

NASA Technical Reports Server (NTRS)

Torres-Peimbert, S.

1986-01-01

A brief review of models of chemical evolution of the interstellar medium in our galaxy and other galaxies is presented. These models predict the time variation and radial dependence of chemical composition in the gas as function of the input parameters; initial mass function, stellar birth rate, chemical composition of mass lost by stars during their evolution (yields), and the existence of large scale mass flows, like infall from the halo, outflow to the intergalactic medium or radial flows within a galaxy. At present there is a considerable wealth of observational data on the composition of HII regions in spiral and irregular galaxies to constrain the models. Comparisons are made between theory and the observed physical conditions. In particular, studies of helium, carbon, nitrogen and oxygen abundances are reviewed. In many molecular clouds the information we have on the amount of H2 is derived from the observed CO column density, and a standard CO/H2 ratio derived for the solar neighborhood. Chemical evolution models and the observed variations in O/H and N/O values, point out the need to include these results in a CO/H2 relation that should be, at least, a function of the O/H ratio. This aspect is also discussed.

First artificial periodic inhomogeneity experiments at HAARP

NASA Astrophysics Data System (ADS)

Hysell, D. L.; McCarrick, M. J.; Fallen, C. T.; Vierinen, J.

2015-03-01

Experiments involving the generation and detection of artificial periodic inhomogeneities have been performed at the High Frequency Active Auroral Research Program (HAARP) facility. Irregularities were created using powerful X-mode HF emissions and then probed using short (10 μs) X- and O-mode pulses. Reception was performed using a portable software-defined receiver together with the crossed rhombic antenna from the local ionosonde. Echoes were observed reliably between about 85 and 140 km altitude with signal-to-noise ratios as high as about 30 dB. The Doppler shift of the echoes can be associated with the vertical neutral wind in this altitude range. Small but persistent Doppler shifts were observed. The decay time constant of the echoes is meanwhile indicative of the ambipolar diffusion coefficient which depends on the plasma temperature, composition, and neutral gas density. The measured time constants appear to be consistent with theoretical expectations and imply a methodology for measuring neutral density profiles. The significance of thermospheric vertical neutral wind and density measurements which are difficult to obtain using ground-based instruments by other means is discussed.

Stochastic modelling of intermittent fluctuations in the scrape-off layer: Correlations, distributions, level crossings, and moment estimation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Garcia, O. E., E-mail: odd.erik.garcia@uit.no; Kube, R.; Theodorsen, A.

A stochastic model is presented for intermittent fluctuations in the scrape-off layer of magnetically confined plasmas. The fluctuations in the plasma density are modeled by a super-position of uncorrelated pulses with fixed shape and duration, describing radial motion of blob-like structures. In the case of an exponential pulse shape and exponentially distributed pulse amplitudes, predictions are given for the lowest order moments, probability density function, auto-correlation function, level crossings, and average times for periods spent above and below a given threshold level. Also, the mean squared errors on estimators of sample mean and variance for realizations of the process bymore » finite time series are obtained. These results are discussed in the context of single-point measurements of fluctuations in the scrape-off layer, broad density profiles, and implications for plasma–wall interactions due to the transient transport events in fusion grade plasmas. The results may also have wide applications for modelling fluctuations in other magnetized plasmas such as basic laboratory experiments and ionospheric irregularities.« less

Ionospheric electron number densities from CUTLASS dual-frequency velocity measurements using artificial backscatter over EISCAT

NASA Astrophysics Data System (ADS)

Sarno-Smith, Lois K.; Kosch, Michael J.; Yeoman, Timothy; Rietveld, Michael; Nel, Amore'; Liemohn, Michael W.

2016-08-01

Using quasi-simultaneous line-of-sight velocity measurements at multiple frequencies from the Hankasalmi Cooperative UK Twin Auroral Sounding System (CUTLASS) on the Super Dual Auroral Radar Network (SuperDARN), we calculate electron number densities using a derivation outlined in Gillies et al. (2010, 2012). Backscatter targets were generated using the European Incoherent Scatter (EISCAT) ionospheric modification facility at Tromsø, Norway. We use two methods on two case studies. The first approach is to use the dual-frequency capability on CUTLASS and compare line-of-sight velocities between frequencies with a MHz or greater difference. The other method used the kHz frequency shifts automatically made by the SuperDARN radar during routine operations. Using ray tracing to obtain the approximate altitude of the backscatter, we demonstrate that for both methods, SuperDARN significantly overestimates Ne compared to those obtained from the EISCAT incoherent scatter radar over the same time period. The discrepancy between the Ne measurements of both radars may be largely due to SuperDARN sensitivity to backscatter produced by localized density irregularities which obscure the background levels.

Analysis of interstellar cloud structure based on IRAS images

NASA Technical Reports Server (NTRS)

Scalo, John M.

1992-01-01

The goal of this project was to develop new tools for the analysis of the structure of densely sampled maps of interstellar star-forming regions. A particular emphasis was on the recognition and characterization of nested hierarchical structure and fractal irregularity, and their relation to the level of star formation activity. The panoramic IRAS images provided data with the required range in spatial scale, greater than a factor of 100, and in column density, greater than a factor of 50. In order to construct densely sampled column density maps of star-forming clouds, column density images of four nearby cloud complexes were constructed from IRAS data. The regions have various degrees of star formation activity, and most of them have probably not been affected much by the disruptive effects of young massive stars. The largest region, the Scorpius-Ophiuchus cloud complex, covers about 1000 square degrees (it was subdivided into a few smaller regions for analysis). Much of the work during the early part of the project focused on an 80 square degree region in the core of the Taurus complex, a well-studied region of low-mass star formation.

Numerical study on the instabilities in H2-air rotating detonation engines

NASA Astrophysics Data System (ADS)

Liu, Yan; Zhou, Weijiang; Yang, Yunjun; Liu, Zhou; Wang, Jianping

2018-04-01

Numerical simulations of rotating detonation engines (RDEs) are performed using two-dimensional Euler equations and a detailed chemistry model of H2-air. Two propagation modes, the one-wave mode and the two-wave mode, are observed in the RDEs. The instabilities of the RDEs are studied and analyzed specifically. A low frequency instability and a high frequency instability are found from the pressure-time trace measured at a fixed location and the average density-time trace of the RDEs. For the low frequency instability, the pressure peak of the pressure-time trace oscillates with a low frequency while the average density is stable. The deviation between the measurement location and the location of the detonation wave results in the low frequency instability. For the high frequency instability, the average density of the RDEs oscillates regularly with a single frequency while the pressure oscillates irregularly with several frequencies. The oscillation of the detonation wave height results in the high frequency instability. Furthermore, the low frequency instability and the high frequency instability both occur in the one-wave and two-wave mode RDEs.

Cutaneous manifestations of the subtypes of polycystic ovary syndrome in Korean patients.

PubMed

Hong, J S; Kwon, H H; Park, S Y; Jung, J Y; Yoon, J Y; Min, S; Choi, Y M; Suh, D H

2015-01-01

Polycystic ovary syndrome (PCOS) is a common endocrinological disorder in women of childbearing-age. Although PCOS has common dermatological manifestations, including hirsutism, acne and androgenetic alopecia, little is known about the dermatological characteristics of PCOS patients in Asia. The goal of this study is to elucidate the dermatological characteristics and metabolic and hormonal parameters of Korean PCOS patients classified by the three ASRM/ESHERE criteria. We investigated 40 untreated PCOS patients who were newly diagnosed in the Department of Obstetrics & Gynecology of Seoul National University Hospital. Patients were classified according to the presence of irregular menstruation (IM), polycystic ovary morphology (PCOM) and hyperandrogenism (HA). Acne specific questionnaire, physical examination, and blood sampling were thoroughly conducted. Twenty four patients (60.0%) met the criteria for the IM/HA/PCOM group and sixteen (40.0%) belonged to the IM/PCOM group. Acne was the most commonly observed dermatological manifestation (95.0%) followed by hirsutism (60.0%), seoborrhea (47.5%), acanthosis nigricans (20.0%) and androgenetic alopecia (12.5%). Hirsutism was more frequently observed in the IM/HA/PCOM group; the prevalence of other cutaneous manifestations did not differ significantly. Acne was most often observed on the face and most acne lesions were distributed on the forehead and cheek. Serum dehydroepiandrosterone sulphate level was higher in IM/HA/PCOM group, while serum cholesterol and high density lipoprotein concentrations were higher in the IM/PCOM group. We described several dermatological manifestations and serum hormonal and metabolic parameters in Korean PCOS patients. Cutaneous manifestations might be the first signs of PCOS; therefore, dermatologists should be more aware of cutaneous manifestations of various ethnicities. © 2014 European Academy of Dermatology and Venereology.

Optical coherence tomography angiography of normal skin and inflammatory dermatologic conditions.

PubMed

Deegan, Anthony J; Talebi-Liasi, Faezeh; Song, Shaozhen; Li, Yuandong; Xu, Jingjiang; Men, Shaojie; Shinohara, Michi M; Flowers, Mary E; Lee, Stephanie J; Wang, Ruikang K

2018-03-01

In clinical dermatology, the identification of subsurface vascular and structural features known to be associated with numerous cutaneous pathologies remains challenging without the use of invasive diagnostic tools. To present an advanced optical coherence tomography angiography (OCTA) method to directly visualize capillary-level vascular and structural features within skin in vivo. An advanced OCTA system with a 1310 nm wavelength was used to image the microvascular and structural features of various skin conditions. Subjects were enrolled and OCTA imaging was performed with a field of view of approximately 10 × 10 mm. Skin blood flow was identified using an optical microangiography (OMAG) algorithm. Depth-resolved microvascular networks and structural features were derived from segmented volume scans, representing tissue slabs of 0-132, 132-330, and 330-924 μm, measured from the surface of the skin. Subjects with both healthy and pathological conditions, such as benign skin lesions, psoriasis, chronic graft-versus-host-disease (cGvHD), and scleroderma, were OCTA scanned. Our OCTA results detailed variations in vascularization and local anatomical characteristics, for example, depth-dependent vascular, and structural alterations in psoriatic skin, alongside their resolve over time; vascular density changes and distribution irregularities, together with corresponding structural depositions in the skin of cGvHD patients; and vascular abnormalities in the nail folds of a patient with scleroderma. OCTA can image capillary blood flow and structural features within skin in vivo, which has the potential to provide new insights into the pathophysiology, as well as dynamic changes of skin diseases, valuable for diagnoses, and non-invasive monitoring of disease progression and treatment. Lasers Surg. Med. 50:183-193, 2018. © 2018 Wiley Periodicals, Inc. © 2018 Wiley Periodicals, Inc.

Scintillation Effects on Space Shuttle GPS Data

NASA Technical Reports Server (NTRS)

Goodman, John L.; Kramer, Leonard

2001-01-01

Irregularities in ionospheric electron density result in variation in amplitude and phase of Global Positioning System (GPS) signals, or scintillation. GPS receivers tracking scintillated signals may lose carrier phase or frequency lock in the case of phase sc intillation. Amplitude scintillation can cause "enhancement" or "fading" of GPS signals and result in loss of lock. Scintillation can occur over the equatorial and polar regions and is a function of location, time of day, season, and solar and geomagnetic activity. Mid latitude regions are affected only very rarely, resulting from highly disturbed auroral events. In the spring of 1998, due to increasing concern about scintillation of GPS signals during the upcoming solar maximum, the Space Shuttle Program began to assess the impact of scintillation on Collins Miniaturized Airborne GPS Receiver (MAGR) units that are to replace Tactical Air Control and Navigation (TACAN) units on the Space Shuttle orbiters. The Shuttle Program must determine if scintillation effects pose a threat to safety of flight and mission success or require procedural and flight rule changes. Flight controllers in Mission Control must understand scintillation effects on GPS to properly diagnose "off nominal" GPS receiver performance. GPS data from recent Space Shuttle missions indicate that the signals tracked by the Shuttle MAGR manifest scintillation. Scintillation is observed as anomalous noise in velocity measurements lasting for up to 20 minutes on Shuttle orbit passes and are not accounted for in the error budget of the MAGR accuracy parameters. These events are typically coincident with latitude and local time occurrence of previously identified equatorial spread F within about 20 degrees of the magnetic equator. The geographic and seasonal history of these events from ground-based observations and a simple theoretical model, which have potential for predicting events for operational purposes, are reviewed.

Bone Mineral Density in Boys Diagnosed with Autism Spectrum Disorder: A Case-Control Study

ERIC Educational Resources Information Center

Barnhill, Kelly; Ramirez, Lucas; Gutierrez, Alan; Richardson, Wendy; Marti, C. Nathan; Potts, Amy; Shearer, Rebeca; Schutte, Claire; Hewitson, Laura

2017-01-01

This study compared bone mineral density (BMD) of the spine obtained by dual-energy X-ray absorptiometry (DEXA), nutritional status, biochemical markers, and gastrointestinal (GI) symptoms in 4-8 year old boys with Autism Spectrum Disorder (ASD) with a group of age-matched, healthy boys without ASD. Boys with ASD had significantly lower spine BMD…

Bones of contention: bone mineral density recovery in celiac disease--a systematic review.

PubMed

Grace-Farfaglia, Patricia

2015-05-07

Metabolic bone disease is a frequent co-morbidity in newly diagnosed adults with celiac disease (CD), an autoimmune disorder triggered by the ingestion of dietary gluten. This systematic review of studies looked at the efficacy of the gluten-free diet, physical activity, nutrient supplementation, and bisphosphonates for low bone density treatment. Case control and cohort designs were identified from PubMed and other academic databases (from 1996 to 2015) that observed newly diagnosed adults with CD for at least one year after diet treatment using the dual-energy x-ray absorptiometry (DXA) scan. Only 20 out of 207 studies met the inclusion criteria. Methodological quality was assessed using the Strengthening of the Reporting of Observational Studies in Epidemiology (STROBE) statement checklist. Gluten-free diet adherence resulted in partial recovery of bone density by one year in all studies, and full recovery by the fifth year. No treatment differences were observed between the gluten-free diet alone and diet plus bisphosphonates in one study. For malnourished patients, supplementation with vitamin D and calcium resulted in significant improvement. Evidence for the impact of physical activity on bone density was limited. Therapeutic strategies aimed at modifying lifestyle factors throughout the lifespan should be studied.

[Infiltration of tumor associated macrophages in multiple myeloma and its clinical significance].

PubMed

Gui, Q L; Wang, Y S; Huang, S; Wan, Y; Wang, H P; Zhu, Z G; Li, M M; Zhu, H Y; Tao, Q S; Shen, Y Y; Zhang, Q; Qin, H

2018-02-14

Objective: To investigate the clinical significance of tumor associated macrophages (TAM) in multiple myeloma (MM) and the relationship with angiogenesis and immunosuppression. Methods: Seventy cases of MM patients diagnosed from August 2015 to June 2017 were enrolled in the study as experimental group, 20 cases of benign hematological diseases (13 with iron deficiency anemia and 7 with megaloblastic anemia) patients as control group. Immunohistochemical method was used to detect the expression of CD163, CD34 and VEGF in bone marrow samples, and flow cytometry was used to detect the proportion of regulatory T cell (Treg cells), ELISA was used to detect the level of IL-10, and the clinical features were analyzed. Results: ①Among the 70 patients, there were 31 males and 39 females with a median age of 65 (50~78) years old. TAM infiltration density, microvascular density (MVD), VEGF expression level, Treg ratio and IL-10 level in bone marrow samples of 70 MM patients were significantly higher than those of benign hematological diseases ( P <0.05). ②In the MM group, the above indexes of the patients with disease stabilized (15 cases) were lower than those of the newly diagnosed group (35 cases) and the relapse refractory group (20 cases) ( P <0.05), those of relapse refractory group were higher than those of newly diagnosed group ( P >0.05). ③Of the 35 newly diagnosed MM patients, 27 completed 4 courses of treatment. In the effective group (15 cases), the TAM infiltration density after treatment was significantly lower than that before treatment, the difference was statistically significant[(20.20±7.66) vs (28.87±11.97), t =2.362, P =0.025]; while in the ineffective group of 12 cases, the difference of the TAM infiltration density before and after treatment was not statistically significant[(42.00±13.76) vs (48.25±13.59), t =1.119, P =0.275]. ④TAM infiltration density in the effective group after bortezomib treatment (21 cases) were lower than those in the non-bortezomib treatment group (18 cases)[(16.52 ±4.26) vs (19.27 ±5.82), t =1.662, P =0.170]. ⑤The TAM infiltration density in MM patients was positively correlated with MVD, VEGF expression level, Treg cell ratio and IL-10 level ( P <0.001). Conclusion: The infiltration of TAM in the microenvironment of MM, which may promoting angiogenesis and inhibiting immune response, is related to the occurrence, development, therapeutic effect and drug resistance of MM.

Radiologic and clinical features of idiopathic granulomatous lobular mastitis mimicking advanced breast cancer.

PubMed

Lee, Jei Hee; Oh, Ki Keun; Kim, Eun-kyung; Kwack, Kyu Sung; Jung, Woo Hee; Lee, Han Kyung

2006-02-28

Idiopathic granulomatous lobular mastitis (IGLM), also known as idiopathic granulomatous mastitis, is a rare chronic inflammatory lesion of the breast that can clinically and radiographically mimic breast carcinoma. The aim of this study was to describe the radiological imaging and clinical features of IGLM in order to better differentiate this disorder from breast cancer. We performed a retrospective analysis of the clinical and radiographic features of 11 women with a total of 12 IGLM lesions. The ages of these women ranged between 29 and 42 years, with a mean age of 34.8 years. Ten patients were examined by both mammography and sonography and one by sonography alone. The sites that were the most frequently involved were the peripheral (6/12), diffuse, (3/12), and subareolar (3/12) regions of the breast. The patient mammograms showed irregular ill-defined masses (7/11), diffuse increased densities (3/11), and one oval obscured mass. In addition, patient sonograms showed irregular tubular lesions (7/12) or lobulated masses with minimal parenchymal distortion (2/12), parenchymal distortion without definite mass lesions (2/12), and one oval mass. Subcutaneous fat obliteration (12/12) and skin thickening (11/12) were also observed in these patients. Contrary to previous reports, skin changes and subareolar involvement were not rare occurrences in IGLM. In conclusion, the sonographic features of IGLM show irregular or tubular hypoechoic masses with minimal parenchymal distortion. Both clinical information and the description of radiographic features of IGLM may aid in the differentiation between IGLM and breast cancer, however histological confirmation is still required for the proper diagnosis and treatment of the disorder.

Radiologic and Clinical Features of Idiopathic Granulomatous Lobular Mastitis Mimicking Advanced Breast Cancer

PubMed Central

Lee, Jei Hee; Kim, Eun-kyung; Kwack, Kyu Sung; Jung, Woo Hee; Lee, Han Kyung

2006-01-01

Idiopathic granulomatous lobular mastitis (IGLM), also known as idiopathic granulomatous mastitis, is a rare chronic inflammatory lesion of the breast that can clinically and radiographically mimic breast carcinoma. The aim of this study was to describe the radiological imaging and clinical features of IGLM in order to better differentiate this disorder from breast cancer. We performed a retrospective analysis of the clinical and radiographic features of 11 women with a total of 12 IGLM lesions. The ages of these women ranged between 29 and 42 years, with a mean age of 34.8 years. Ten patients were examined by both mammography and sonography and one by sonography alone. The sites that were the most frequently involved were the peripheral (6/12), diffuse, (3/12), and subareolar (3/12) regions of the breast. The patient mammograms showed irregular ill-defined masses (7/11), diffuse increased densities (3/11), and one oval obscured mass. In addition, patient sonograms showed irregular tubular lesions (7/12) or lobulated masses with minimal parenchymal distortion (2/12), parenchymal distortion without definite mass lesions (2/12), and one oval mass. Subcutaneous fat obliteration (12/12) and skin thickening (11/12) were also observed in these patients. Contrary to previous reports, skin changes and subareolar involvement were not rare occurrences in IGLM. In conclusion, the sonographic features of IGLM show irregular or tubular hypoechoic masses with minimal parenchymal distortion. Both clinical information and the description of radiographic features of IGLM may aid in the differentiation between IGLM and breast cancer, however histological confirmation is still required for the proper diagnosis and treatment of the disorder. PMID:16502488

Global view of the E region irregularity and convection velocities in the high-latitude Southern Hemisphere

NASA Astrophysics Data System (ADS)

Forsythe, Victoriya V.; Makarevich, Roman A.

2017-02-01

Occurrence of the E region plasma irregularities is investigated using two Super Dual Auroral Radar Network (SuperDARN) South Pole (SPS) and Zhongshan (ZHO) radars that sample the same magnetic latitude deep within the high-latitude plasma convection pattern but from two opposite directions. It is shown that the SPS and ZHO velocity distributions and their variations with the magnetic local time are different, with each distribution being asymmetric; i.e., a particular velocity polarity is predominant. This asymmetry in the E region velocity distribution is associated with the bump-on-tail of the distribution near the nominal ion acoustic speed Cs that is most likely due to the Farley-Buneman instability (FBI) echoes or an inflection point of the distribution below nominal Cs that is most likely due to the gradient drift instability echoes. In contrast, the distribution of the convection velocity component was found to be symmetric, i.e., with no bump-on-tail or an inflection point, but with a bias (i.e., uniform shift) toward a particular polarity. It is demonstrated that the asymmetry in the convection pattern between the eastward and westward zonal components is unexpectedly strong, with the westward zonal component being predominant, especially at lower latitudes, while also exhibiting a strong interplanetary magnetic field By dependence. The observations are consistent with the notion that the asymmetry in the E region velocity distribution is highly sensitive to the bias in the convection component caused by the zonal convection component asymmetry and that the bump-on-tail or inflection point features may also depend on the irregularity height and the presence of strong density gradients modifying the FBI threshold value.

Exploring the color of transition metal ions in irregular coordination geometries: new colored inorganic oxides based on the spiroffite structure, Zn(2-x)M(x)Te3O8 (M = Co, Ni, Cu).

PubMed

Tamilarasan, S; Sarma, Debajit; Bhattacharjee, S; Waghmare, U V; Natarajan, S; Gopalakrishnan, J

2013-05-20

We describe the synthesis, crystal structures, and optical absorption spectra of transition metal-substituted spiroffite derivatives, Zn(2-x)M(x)Te3O8 (M(II) = Co, Ni, Cu; 0 < x ≤ 1.0). The oxides are readily synthesized by solid state reaction of stoichiometric mixtures of the constituent binaries at 620 °C. Reitveld refinement of the crystal structures from powder X-ray diffraction (XRD) data shows that the Zn/MO6 octahedra are strongly distorted, as in the parent Zn2Te3O8 structure, consisting of five relatively short Zn/M(II)-O bonds (1.898-2.236 Å) and one longer Zn/M(II)-O bond (2.356-2.519 Å). We have interpreted the unique colors and the optical absorption/diffuse reflectance spectra of Zn(2-x)M(x)Te3O8 in the visible, in terms of the observed/irregular coordination geometry of the Zn/M(II)-O chromophores. We could not however prepare the fully substituted M2Te3O8 (M(II) = Co, Ni, Cu) by the direct solid state reaction method. Density Functional Theory (DFT) modeling of the electronic structure of both the parent and the transition metal substituted derivatives provides new insights into the bonding and the role of transition metals toward the origin of color in these materials. We believe that transition metal substituted spiroffites Zn(2-x)M(x)Te3O8 reported here suggest new directions for the development of colored inorganic materials/pigments featuring irregular/distorted oxygen coordination polyhedra around transition metal ions.

Solo dwarfs I: survey introduction and first results for the Sagittarius dwarf irregular galaxy

NASA Astrophysics Data System (ADS)

Higgs, C. R.; McConnachie, A. W.; Irwin, M.; Bate, N. F.; Lewis, G. F.; Walker, M. G.; Côté, P.; Venn, K.; Battaglia, G.

2016-05-01

We introduce the Solitary Local dwarfs survey (Solo), a wide-field photometric study targeting every isolated dwarf galaxy within 3 Mpc of the Milky Way. Solo is based on (u)gi multiband imaging from Canada-France-Hawaii Telescope/MegaCam for northern targets, and Magellan/Megacam for southern targets. All galaxies fainter than MV ≃ -18 situated beyond the nominal virial radius of the Milky Way and M31 (≳300 kpc) are included in this volume-limited sample, for a total of 42 targets. In addition to reviewing the survey goals and strategy, we present results for the Sagittarius dwarf irregular galaxy (Sag DIG), one of the most isolated, low-mass galaxies, located at the edge of the Local Group. We analyse its resolved stellar populations and their spatial distributions. We provide updated estimates of its central surface brightness and integrated luminosity, and trace its surface brightness profile to a level fainter than 30 mag arcsec-2. Sag DIG is well described by a highly elliptical (disc-like) system following a single component Sérsic model. However, a low-level distortion is present at the outer edges of the galaxy that, were Sag DIG not so isolated, would likely be attributed to some kind of previous tidal interaction. Further, we find evidence of an extremely low level, extended distribution of stars beyond ˜5 arcmin (>1.5 kpc) that suggests Sag DIG may be embedded in a very low-density stellar halo. We compare the stellar and H I structures of Sag DIG, and discuss results for this galaxy in relation to other isolated, dwarf irregular galaxies in the Local Group.

Space Weather Studies Using the Low-Latitude Ionospheric Sensor Network (LISN)

NASA Astrophysics Data System (ADS)

Valladares, C. E.; Pacheco, E.

2014-12-01

LISN is an array of small instruments that operates as a real-time distributed observatory to understand the complex day-to-day variability and the extreme state of disturbance that occurs in the South American low-latitude ionosphere nearly every day after sunset. The LISN observatory aims to forecast the initiation and transport of plasma bubbles across the South American continent. The occurrence of this type of plasma structures and their embedded irregularities poses a prominent natural hazard to communication, navigation and high precision pointing systems. As commercial and military aviation is increasingly reliant on Global Navigation Satellite Systems (GNSS) any interruption due to ionospheric irregularities or errors due to large density gradients constitutes a serious threat to passengers and crew. Therefore, it is important to understand the conditions and sources that contribute to the formation of these irregularities. To achieve high quality regional nowcasts and forecasts, the LISN system was designed to include a dense coverage of the South American landmass with 47 GPS receivers, 5 flux-gate magnetometers distributed on 2 base lines and 3 Vertical Incidence Pulsed Ionospheric Radar (VIPIR) ionosondes deployed along the same magnetic meridian that intersects the magnetic equator at 68° W. This presentation will provide a summary of recent instrument installations and new processing techniques that have been developed under the LISN project. We will also present the results of recent efforts to detect TIDs and TEC plasma depletions on a near real-time basis. We will describe a method to estimate the zonal velocity and tilt of the plasma bubbles/depletions by combining observations of TEC depletions acquired with adjacent receivers, making it possible to predict precisely their future locations.

Evidence for metabolic and reproductive phenotypes in mothers of women with polycystic ovary syndrome

PubMed Central

Sam, Susan; Legro, Richard S.; Essah, Paulina A.; Apridonidze, Teimuraz; Dunaif, Andrea

2006-01-01

Dyslipidemia is a feature of polycystic ovary syndrome (PCOS), but its pathogenesis remains controversial. We performed this study of mothers of women with PCOS to test the hypothesis that dyslipidemia is a heritable trait in families of women with PCOS and to investigate the impact of age on reproductive and metabolic phenotypes. Fasting blood was obtained in 215 non-Hispanic white mothers of women with PCOS and 62 control women. The prevalence of metabolic syndrome was compared with that in non-Hispanic white women of comparable age from the National Health and Nutrition Examination Survey III. Mothers had higher total (P < 0.001) and low-density lipoprotein (LDL) cholesterol levels (P = 0.007), whereas high-density lipoprotein and triglyceride levels did not differ compared with control women. The only predictors of LDL levels in mothers were their daughters’ LDL levels (r2 = 0.11, P < 0.001) and their own unbound testosterone levels (r2 = 0.04, P = 0.03). The prevalence of metabolic syndrome was increased in obese (body mass index ≥ 30 kg/m2) mothers compared with obese non-Hispanic white women from the National Health and Nutrition Examination Survey III (P = 0.04). Thirty-one percent of mothers reported a history of menstrual irregularity. These mothers had higher androgen levels, markers of insulin resistance, and LDL levels than mothers with regular menses. LDL levels are increased in mothers of women with PCOS, suggestive of a heritable trait. A history of menstrual irregularity identifies mothers with features of PCOS. Obese mothers have a very high prevalence of metabolic syndrome. These findings suggest that both the reproductive and metabolic abnormalities persist with age in PCOS. PMID:16632599

VHF Scintillation in an Artificially Heated Ionosphere

NASA Astrophysics Data System (ADS)

Suszcynsky, D. M.; Layne, J.; Light, M. E.; Pigue, M. J.; Rivera, L.

2017-12-01

As part of an ongoing project to characterize very-high-frequency (VHF) radio wave propagation through structured ionospheres, Los Alamos National Laboratory has been conducting a set of experiments to measure the scintillation effects of VHF transmissions under a variety of ionospheric conditions. Previous work (see 2015 Fall AGU poster by D. Suszcynsky et al.) measured the S4 index and ionospheric coherence bandwidth in the 32 - 44 MHz frequency range under naturally scintillated conditions in the equatorial region at Kwajalein Atoll during three separate campaigns centered on the 2014 and 2015 equinoxes. In this paper, we will present preliminary results from the February and September, 2017 High Altitude Auroral Research Project (HAARP) Experimental Campaigns where we are attempting to make these measurements under more controlled conditions using the HAARP ionospheric heater in a twisted-beam mode. Two types of measurements are made by transmitting VHF signals through the heated ionospheric volume to the Radio Frequency Propagation (RFProp) satellite experiment. The S4 scintillation index is determined by measuring the power fluctuations of a 135-MHz continuous wave signal and the ionospheric coherence bandwidth is simultaneously determined by measuring the delay spread of a frequency-modulated continuous wave (FMCW) signal in the 130 - 140 MHz frequency range. Additionally, a spatial Fourier transform of the CW time series is used to calculate the irregularity spectral density function. Finally, the temporal evolution of the time series is used to characterize spread-Doppler clutter effects arising from preferential ray paths to the satellite due to refraction off of isolated density irregularities. All results are compared to theory and scaled for comparison to the 32 - 44 MHz Kwajalein measurements.

Effect of mid-scan breathing changes on quality of 4DCT using a commercial phase-based sorting algorithm.

PubMed

Noel, Camille E; Parikh, Parag J

2011-05-01

Though it is known that irregular breathing can introduce artifacts in commercial 4DCT, this has not been systematically explored. The purpose of this study is to investigate the effect of variations in basic parameters of the breathing wave on 4DCT imaging quality. A four-dimensional motion platform holding an acrylic sphere was scanned while moving in a trajectory modeled from a lung cancer patient. A bellows device was used as a respiratory surrogate, and the images were sorted by a commercial phase-based sorting algorithm. Motion during the first half of the scan was produced at a baseline trajectory with a consistent frequency and amplitude of 15 breaths per minute and 1 cm, peak to peak. The two parameters were then varied mid-scan to new frequency and amplitude values, with frequencies ranging from 7.5 to 22 bpm and amplitudes ranging from 0.5 to 1.5 cm. Image sets representing four respiratory phases were contoured. Each set was analyzed to compare centroid displacement, density homogeneity, and volumetric and geometric distortions of the imaged sphere. Undercoverage of the target ITV and overcoverage of healthy tissue was also evaluated. Changes in amplitude of 25% or more, with or without changes in frequency, consistently caused measurable distortions in shape, position, and density of the imaged sphere. Frequency changes over 50% showed a similar trend. This study suggests that basic breathing statistics can be used to quickly assess the quality of a 4DCT scan prior to image reconstruction. Such information can help give indication of the proper course of action when irregular breathing patterns are observed during CT scanning.

Graded effects of regularity in language revealed by N400 indices of morphological priming.

PubMed

Kielar, Aneta; Joanisse, Marc F

2010-07-01

Differential electrophysiological effects for regular and irregular linguistic forms have been used to support the theory that grammatical rules are encoded using a dedicated cognitive mechanism. The alternative hypothesis is that language systematicities are encoded probabilistically in a way that does not categorically distinguish rule-like and irregular forms. In the present study, this matter was investigated more closely by focusing specifically on whether the regular-irregular distinction in English past tenses is categorical or graded. We compared the ERP priming effects of regulars (baked-bake), vowel-change irregulars (sang-sing), and "suffixed" irregulars that display a partial regularity (suffixed irregular verbs, e.g., slept-sleep), as well as forms that are related strictly along formal or semantic dimensions. Participants performed a visual lexical decision task with either visual (Experiment 1) or auditory prime (Experiment 2). Stronger N400 priming effects were observed for regular than vowel-change irregular verbs, whereas suffixed irregulars tended to group with regular verbs. Subsequent analyses decomposed early versus late-going N400 priming, and suggested that differences among forms can be attributed to the orthographic similarity of prime and target. Effects of morphological relatedness were observed in the later-going time period, however, we failed to observe true regular-irregular dissociations in either experiment. The results indicate that morphological effects emerge from the interaction of orthographic, phonological, and semantic overlap between words.

Excitation of ground vibration due to the passage of trains over a track with trackbed irregularities and a varying support stiffness

NASA Astrophysics Data System (ADS)

Auersch, Lutz

2015-01-01

Train-induced ground vibration can be excited by wheel and track irregularities and by two kinds of irregularities of the soil, by geometric irregularities or by the spatially varying soil stiffness. For both types of irregularities, the effective track irregularity on top of the track is calculated in wavenumber domain and with wavenumber integrals. For a general multi-beam track model, the wavenumber integrals are solved numerically. The irregularities of the soil are filtered by the track when transferred from the bottom to the top of the track. The high-wavenumber irregularities are strongly reduced due to the bending stiffness of the track and the compliance of the support. In addition, soft track elements reduce directly the stiffness variation of the support. Therefore, the mitigation effect of elastic track elements for these excitation components seems to be important. For under-sleeper pads and slab tracks, calculation and measurements are presented including additional excitation components and the dynamic vehicle-track interaction, and the relevance of the excitation mechanisms is discussed based on the dynamic forces which are acting on the ground. Due to the restricted amplitudes, the parametric excitation by the stiffness variation seems to be less important than the geometric irregularities. The calculations yield the correct trends of the measurements and many details of the measured ballast, slab, and under-sleeper-pad tracks.

Early-Time HANE Simulation and Experiment

DTIC Science & Technology

1987-05-01

we suggest attacking the question of structure with target variation. Irregular structure in laboratory simulations of HANE’s can arise from...plasma instabilities even when the illuminating laser beam and target are optimized to yield a very uniform initial expansion. Irregularities ... irregular structure be purposely explored. In particular we encourage the use of a wide variety of inhomogeneous targets. Target irregularities

Influence of initial stress, irregularity and heterogeneity on Love-type wave propagation in double pre-stressed irregular layers lying over a pre-stressed half-space

NASA Astrophysics Data System (ADS)

Singh, Abhishek Kumar; Das, Amrita; Parween, Zeenat; Chattopadhyay, Amares

2015-10-01

The present paper deals with the propagation of Love-type wave in an initially stressed irregular vertically heterogeneous layer lying over an initially stressed isotropic layer and an initially stressed isotropic half-space. Two different types of irregularities, viz., rectangular and parabolic, are considered at the interface of uppermost initially stressed heterogeneous layer and intermediate initially stressed isotropic layer. Dispersion equations are obtained in closed form for both cases of irregularities, distinctly. The effect of size and shape of irregularity, horizontal compressive initial stress, horizontal tensile initial stress, heterogeneity of the uppermost layer and width ratio of the layers on phase velocity of Love-type wave are the major highlights of the study. Comparative study has been made to identify the effects of different shapes of irregularity, presence of heterogeneity and initial stresses. Numerical computations have been carried out and depicted by means of graphs for the present study.

Properties of the Irregular Satellite System around Uranus Inferred from K2, Herschel, and Spitzer Observations

NASA Astrophysics Data System (ADS)

Farkas-Takács, A.; Kiss, Cs.; Pál, A.; Molnár, L.; Szabó, Gy. M.; Hanyecz, O.; Sárneczky, K.; Szabó, R.; Marton, G.; Mommert, M.; Szakáts, R.; Müller, T.; Kiss, L. L.

2017-09-01

In this paper, we present visible-range light curves of the irregular Uranian satellites Sycorax, Caliban, Prospero, Ferdinand, and Setebos taken with the Kepler Space Telescope over the course of the K2 mission. Thermal emission measurements obtained with the Herschel/PACS and Spitzer/MIPS instruments of Sycorax and Caliban were also analyzed and used to determine size, albedo, and surface characteristics of these bodies. We compare these properties with the rotational and surface characteristics of irregular satellites in other giant planet systems and also with those of main belt and Trojan asteroids and trans-Neptunian objects. Our results indicate that the Uranian irregular satellite system likely went through a more intense collisional evolution than the irregular satellites of Jupiter and Saturn. Surface characteristics of Uranian irregular satellites seem to resemble the Centaurs and trans-Neptunian objects more than irregular satellites around other giant planets, suggesting the existence of a compositional discontinuity in the young solar system inside the orbit of Uranus.

Polycystic ovarian morphology in normal women does not predict the development of polycystic ovary syndrome.

PubMed

Murphy, M K; Hall, J E; Adams, J M; Lee, H; Welt, C K

2006-10-01

Polycystic ovarian morphology (PCOM) is present in 25% of normal women in the absence of polycystic ovary syndrome (PCOS); however, the natural history of PCOM is unknown. We hypothesized that the presence of PCOM predisposes the development of PCOS. The study was a longitudinal follow-up study over 8.2 +/- 5.2 yr (mean +/- sd; range 1.7-17.5 yr). The study took place in an outpatient setting. Women who took part in a previous study as a normal control and had an ultrasound examination (n = 40) participated. Subjects underwent an interval menstrual history, physical exam, blood sampling, and repeat ultrasound in the follicular phase. Development of PCOS was diagnosed by irregular menses and hyperandrogenism, in the absence of other disorders. Changes in ovarian morphology over time were evaluated. At the baseline visit, 23 women (57.5%) had PCOM and 17 (42.5%) had normal ovarian morphology. One subject with PCOM developed irregular menses and presumptive PCOS. Eleven subjects with PCOM no longer met the criteria for PCOM at follow-up. There was no factor that predicted the change to normal ovarian morphology at the follow-up visit. These data suggest that PCOM in women with regular ovulatory cycles does not commonly predispose the development of PCOS. Although it is unusual to develop PCOM if the ovaries are normal on first assessment, ovaries in women with PCOM no longer meet the criteria for PCOM in approximately half of cases over time.

Arrhythmia-induced cardiomyopathies: the riddle of the chicken and the egg still unanswered?

PubMed

Simantirakis, Emmanuel N; Koutalas, Emmanuel P; Vardas, Panos E

2012-04-01

The hypothesis testing of inappropriate fast, irregular, or asynchronous myocardial contraction provoking cardiomyopathy has been the primary focus of numerous research efforts, especially during the last few decades. Rapid ventricular rates resulting from supraventricular arrhythmias and atrial fibrillation (AF), irregularity of heart rhythm-basic element of AF-and asynchrony, as a consequence of right ventricular pacing, bundle branch block, or frequent premature ventricular complexes, have been established as primary causes of arrhythmia-induced cardiomyopathy. The main pathophysiological pathways involved have been clarified, including neurohumoral activation, energy stores depletion, and abnormalities in stress and strain. Unfortunately, from a clinical point of view, patients usually seek medical advice only when symptoms develop, while the causative arrhythmia may be present for months or years, resulting in myocardial remodelling, diastolic, and systolic dysfunction. In some cases, making a definite diagnosis may become a strenuous exercise for the treating physician, as the arrhythmia may not be present and, additionally, therapy must be applied for the diagnosis to be confirmed retrospectively. The diagnostic process is also hardened due to the fact that strict diagnosing criteria are still a matter of discrepancy. Therapy options include pharmaceutical agents trials, catheter-based therapies and, in the context of chronic ventricular pacing, resynchronization. For the majority of patients, partial or complete recovery is expected, although they have to be followed up thoroughly due to the risk of recurrence. Large, randomized controlled trials are more than necessary to optimize patients' stratification and therapeutic strategy choices.

Umbilical cord mesenchymal stem cell (UC-MSC) transplantations for cerebral palsy

PubMed Central

Dong, Huajiang; Li, Gang; Shang, Chongzhi; Yin, Huijuan; Luo, Yuechen; Meng, Huipeng; Li, Xiaohong; Wang, Yali; Lin, Ling; Zhao, Mingliang

2018-01-01

This study reports a case of a 4-year-old boy patient with abnormalities of muscle tone, movement and motor skills, as well as unstable gait leading to frequent falls. The results of the electroencephalogram (EEG) indicate moderately abnormal EEG, accompanied by irregular seizures. Based on these clinical characteristics, the patient was diagnosed with cerebral palsy (CP) in our hospital. In this study, the patient was treated with umbilical cord mesenchymal stem cell (UC-MSC) transplantation therapy. This patient received UC-MSC transplantation 3 times (5.3*107) in total. After three successive cell transplantations, the patient recovered well and showed obvious improvements in EEG and limb strength, motor function, and language expression. However, the improvement in intelligence quotient (IQ) was less obvious. These results indicate that UC-MSC transplantation is a promising treatment for cerebral palsy. PMID:29636880

Acquired Fanconi syndrome with proximal tubular cytoplasmic fibrillary inclusions of λ light chain restriction.

PubMed

Yao, Ying; Wang, Su-Xia; Zhang, You-Kang; Wang, Yan; Liu, Li; Liu, Gang

2014-01-01

Light chain proximal tubulopathy is a rarely reported entity associated with plasma cell dyscrasia that classically manifests as acquired Fanconi syndrome and is characterized by the presence of κ-restricted crystals in the proximal tubular cytoplasm. We herein present a case of multiple myeloma with Fanconi syndrome and acute kidney injury due to light chain proximal tubulopathy with light chain cast nephropathy. Prominent phagolysosomes and numerous irregularly shaped inclusions with a fibrillary matrix in the cytoplasm of the proximal tubules were identified on electron microscopy. A monotypic light chain of the λ type was detected in the distal tubular casts, proximal tubular cytoplasmic lysosomes and fibrillary inclusions on immunofluorescence and immune electron microscopy. This case underscores the importance of conducting careful ultrastructural investigations and immunocytologic examinations of light chains for detecting and diagnosing light chain proximal tubulopathy.

Percutaneous transcatheter arterial embolization in haemodynamically stable patients with blunt splenic injury

PubMed Central

Popovic, Peter; Stanisavljevic, Dragoje; Jeromel, Miran

2010-01-01

Background The nonoperative management of the blunt splenic injury in haemodynamically stable patients has become an accepted treatment in recent years. We present a case of the blunt splenic injury successfully treated by supraselective embolization with microspheres. Case report. A young hockey player was brought to the Emergency Department with the history of blunt abdominal trauma 2 h earlier. A Grade III splenic injury with haemoperitoneum was diagnosed on sonographic evaluation and the patient was treated with the selective distal splenic artery embolization with microspheres. Postprocedural ultrasound and computed tomography follow-up a year later revealed only a small area of parenchymal irregularity. Conclusions The percutaneous splenic arterial embolization has a major role in the management of traumatic splenic injuries. Embolization is particularly beneficial in injuries of grade III or higher. PMID:22933888

Cardiac mesothelial papillary hyperplasia in four dogs.

PubMed

Kirejczyk, Shannon G; Burnum, Anne L; Brown, Corrie C; Sakamoto, Kaori; Rissi, Daniel R

2018-05-01

Mesothelial papillary hyperplasia (MPH) has been described as an incidental finding on the epicardial surface of clinically normal laboratory Beagle dogs. We describe MPH in 4 dogs diagnosed with acute cardiac tamponade (1 case) or chronic cardiac disease (3 cases). Cardiac MPH appeared as distinct, soft, irregular villous plaques on the epicardial surface of the auricles and occasionally the ventricles. Histologically, areas of MPH were composed of multiple papillary fronds arising from the epicardial surface and projecting into the pericardial space. Fronds were covered by cuboidal and occasionally vacuolated mesothelial cells and were supported by loose fibrovascular stroma with various degrees of edema and inflammation. Although these may represent incidental findings with no clinical significance, the gross appearance warrants differentiation from other conditions. Additional insight into the pathogenesis of MPH is needed to fully understand its significance in the face of concurrent cardiac disease.

What Are Menstrual Irregularities?

MedlinePlus

... menstrual irregularities? For most women, a normal menstrual cycle ranges from 21 to 35 days. 1 However, 14% to 25% of women have irregular menstrual cycles, meaning the cycles are shorter or longer than ...

Equatorial Ionospheric Irregularities Study from ROCSAT Data

DTIC Science & Technology

2017-10-20

ApprovedOMB No. 0704-0188 The public reporting burden for this collection of information is estimated to average 1 hour per response, including the time ...scintillation in the Indian and Taiwan sector, it was concluded that the longitudinal/local- time dependence of irregularity/scintillation occurrences...irregularities/scintillation in the Indian and Taiwan sector, we have concluded that the longitudinal/local- time dependence of irregularity/scintillation

[Is there a relation between weight in rats, bone density, ash weight and histomorphometric indicators of trabecular volume and thickness in the bones of extremities?].

PubMed

Zák, J; Kapitola, J; Povýsil, C

2003-01-01

Authors deal with question, if there is possibility to infer bone histological structure (described by histomorphometric parameters of trabecular bone volume and trabecular thickness) from bone density, ash weight or even from weight of animal (rat). Both tibias of each of 30 intact male rats, 90 days old, were processed. Left tibia was utilized to the determination of histomorphometric parameters of undecalcified bone tissue patterns by automatic image analysis. Right tibia was used to the determination of values of bone density, using Archimedes' principle. Values of bone density, ash weight, ash weight related to bone volume and animal weight were correlated with histomorphometric parameters (trabecular bone volume, trabecular thickness) by Pearson's correlation test. One could presume the existence of relation between data, describing bone mass at the histological level (trabecular bone of tibia) and other data, describing mass of whole bone or even animal mass (weight). But no statistically significant correlation was found. The reason of the present results could be in the deviations of trabecular density in marrow of tibia. Because of higher trabecular bone density in metaphyseal and epiphyseal regions, the histomorphometric analysis of trabecular bone is preferentially done in these areas. It is possible, that this irregularity of trabecular tibial density could be the source of the deviations, which could influence the results of correlations determined. The values of bone density, ash weight and animal weight do not influence trabecular bone volume and vice versa: static histomorphometric parameters of trabecular bone do not reflect bone density, ash weight and weight of animal.

Of PCOS symptoms, hirsutism has the most significant impact on the quality of life of Iranian women.

PubMed

Khomami, Mahnaz Bahri; Tehrani, Fahimeh Ramezani; Hashemi, Somayeh; Farahmand, Maryam; Azizi, Fereidoun

2015-01-01

Polycystic ovary syndrome is a common endocrine disorder affecting women both physically and psychologically and can lead to a poor quality of life compared to their normal counterparts. The aim of the present study was to assess the impact of various clinical features of polycystic ovary syndrome on the health-related quality of life of Iranian women diagnosed with this syndrome. A total of 796 women diagnosed with polycystic ovary syndrome, aged 15-49 years, completed the questionnaires, interviews, and medical assessments required for this study. A reliable and validated Persian version of the health-related quality of life questionnaire for polycystic ovary syndrome patients was used. Linear regression models were used to assess the association between the symptoms of polycystic ovary syndrome and health-related quality of life. The mean age of participants was 28.02 years. 35.4% of the subjects were classified as overweight or obese. Hirsutism, was reported to have the strongest impact on the patients' health-related quality of life, followed in descending order by body mass index, irregular menses and infertility. The relative level of hirsutism was directly proportional to decrease in health-related quality of life score (p<0.001). The results of the study found that hirsutism had the strongest impact on the health-related quality of life measures in Iranian women diagnosed with polycystic ovary syndrome. Health care officials need to evaluate in depth the effect of each clinical feature of polycystic ovary syndrome separately and design management strategies, keeping in mind the psychological and physical manifestations.

Central congenital hypothyroidism due to gestational hyperthyroidism: detection where prevention failed.

PubMed

Kempers, Marlies J E; van Tijn, David A; van Trotsenburg, A S Paul; de Vijlder, Jan J M; Wiedijk, Brenda M; Vulsma, Thomas

2003-12-01

Much worldwide attention is given to the adverse effects of maternal Graves' disease on the fetal and neonatal thyroid and its function. However, reports concerning the adverse effects of maternal Graves' disease on the pituitary function, illustrated by the development of central congenital hypothyroidism (CCH) in the offspring of these mothers, are scarce. We studied thyroid hormone determinants of 18 children with CCH born to mothers with Graves' disease. Nine mothers were diagnosed after pregnancy, the majority after their children were detected with CCH by neonatal screening. Four mothers were diagnosed during pregnancy and treated with antithyroid drugs since diagnosis. Another four mothers were diagnosed before pregnancy, but they used antithyroid drugs irregularly; free T(4) concentrations less than 1.7 ng/dl (<22 pmol/liter) were not encountered during pregnancy. All neonates had decreased plasma free T(4) concentrations (range 0.3-0.9 ng/dl, 3.9-11.5 pmol/liter); plasma TSH ranged between 0.1 and 6.6 mU/liter. TRH tests showed pituitary dysfunction. Seventeen children needed T(4) supplementation. Because all mothers were insufficiently treated during pregnancy, it is hypothesized that a hyperthyroid fetal environment impaired maturation of the fetal hypothalamic-pituitary-thyroid system. The frequent occurrence of this type of CCH (estimated incidence 1:35000) warrants early detection and treatment to minimize the risk of cerebral damage. A T(4)-based screening program appears useful in detecting this type of CCH. However, the preferential and presumably best strategy to prevent CCH caused by maternal Graves' disease is preserving euthyroidism throughout pregnancy.

Homeostatic Model Assessment for Insulin Resistance (HOMA-IR): A Better Marker for Evaluating Insulin Resistance Than Fasting Insulin in Women with Polycystic Ovarian Syndrome.

PubMed

Majid, Hafsa; Masood, Qamar; Khan, Aysha Habib

2017-03-01

To assess the utility of HOMA-IR in assessing insulin resistance in patients with polycystic ovary syndrome (PCOS) and compare it with fasting insulin for assessing insulin resistance (IR). Observational study. Section of Clinical Chemistry, Department of Pathology and Laboratory Medicine, The Aga Khan University Hospital, Karachi, from January 2009 to September 2012. Medical chart review of all women diagnosed with PCOS was performed. Of the 400 PCOS women reviewed, 91 met the inclusion criteria. Insulin resistance was assessed by calculating HOMA-IR using the formula (fasting glucose x fasting insulin)/405, taking normal value <2 in adults and hyperinsulinemia based on fasting insulin levels ≥12 µIU/ml. A total of 91 premenopausal women diagnosed with PCOS were included. Mean age was 30 ±5.5 years. Mean HOMA-IR of women was 3.1 ±1.7, respectively with IR in 69% (n=63) women, while hyperinsulinemia was present in 60% (n=55) women (fasting Insulin 18.5 ±5.8 µIU/ml). Hyperandrogenism was present in 53.8% (n=49), whereas 38.5% (n=35) women had primary infertility or subfertility, while 65.9% (n=60) had menstrual irregularities; and higher frequencies were observed in women with IR. Eight subjects with IR and endocrine abnormalities were missed by fasting insulin. Insulin resistance is common in PCOS and it is likely a pathogenic factor for development of PCOS. HOMAIR model performed better than hyperinsulinemia alone for diagnosing IR.

Alternative diagnosis in the putative ventilator-associated pneumonia patient not meeting lavage-based diagnostic criteria.

PubMed

Schoemakers, Rik J; Schnabel, Ronny; Oudhuis, Guy J; Linssen, Catharina F M; van Mook, Walther N K A; Verbon, Annelies; Bergmans, Dennis C J J

2014-12-01

The clinical picture of ventilator-associated pneumonia (VAP) can be mimicked by other infectious and non-infectious diseases. The aim of this study was to determine the alternative diagnoses and to develop a diagnostic flow chart for patients suspected of having VAP not meeting the diagnostic broncho-alveolar lavage (BAL) criteria. Adult intensive care patients with a clinical suspicion of VAP and negative BAL results were included. The clinical suspicion of VAP was based on the combination of clinical, radiological, and microbiological criteria. BAL was considered positive if cell differentiation revealed ≥ 2% cells with intracellular organisms and/or quantitative culture results of ≥ 10(4) cfu/ml. The most likely alternative diagnosis of fever and pulmonary densities was retrospectively determined by two authors independently. In all, 110 of 207 patients with suspected VAP did not meet the diagnostic BAL criteria and required further diagnostic evaluation. In 67 patients an alternative diagnosis for fever could be found. In 51 patients an alternative diagnosis of both fever and pulmonary densities could be established. In almost 40% of patients no alternative diagnosis could be provided. Non-bacterial pneumonia was diagnosed in 10 patients with Herpes simplex virus 1 (HSV-1) as the most common pathogen. In eight patients non-infectious pneumonitis was diagnosed. Due to the wide range of alternative diagnoses and applied tests the diagnostic work-up proved to be necessarily individualized and guided by repeated clinical assessment. The most frequently found alternative diagnoses were viral pneumonia and non-infectious pneumonitis.

Cutaneous amelanotic signet-ring cell malignant melanoma with interspersed myofibroblastic differentiation in a young cat.

PubMed

Hirz, Manuela; Herden, Christiane

2016-07-01

The diagnosis of malignant melanoma can be difficult because these tumors can be amelanotic and may contain diverse variants and divergent differentiations, of which the signet-ring cell subtype is very rare and has only been described in humans, dogs, cats, and a hamster. We describe herein histopathologic and immunohistochemical approaches taken to diagnose a case of signet-ring cell malignant melanoma with myofibroblastic differentiation in a cat. A tumor within the abdominal skin of a 2-year-old cat was composed of signet-ring cells and irregularly interwoven streams of spindle cells. Both neoplastic cell types were periodic-acid-Schiff, Fontana, and Sudan black B negative. Signet-ring cells strongly expressed vimentin and S100 protein. Spindle cells strongly expressed vimentin and smooth muscle actin; some cells expressed S100, moderately neuron-specific enolase, and others variably actin and desmin. A few round cells expressed melan A, and a few plump spindle cells expressed melan A and PNL2, confirming the diagnosis of amelanotic signet-ring cell malignant melanoma with myofibroblastic differentiation in a cat. Differential diagnoses were excluded, including signet-ring cell forms of adenocarcinomas, lymphomas, liposarcomas, leiomyosarcomas, squamous cell carcinomas, basal cell carcinomas, and adnexal tumors. © 2016 The Author(s).

Clinical and dermoscopic clues to differentiate pigmented nail bands: an International Dermoscopy Society study.

PubMed

Benati, E; Ribero, S; Longo, C; Piana, S; Puig, S; Carrera, C; Cicero, F; Kittler, H; Deinlein, T; Zalaudek, I; Stolz, W; Scope, A; Pellacani, G; Moscarella, E; Piraccini, B M; Starace, M; Argenziano, G

2017-04-01

Longitudinal melanonychia might be difficult to differentiate and the use of dermoscopy can be useful for the preoperative evaluation and management decision. The aim of our study was to investigate clinical and dermoscopic criteria of acquired longitudinal melanonychia in adults to identify the best predictors of melanoma using a multivariate analysis and to explore eventual new dermoscopic criteria for nail melanoma diagnosis. In this retrospective observational study, 82 histopathologically diagnosed, acquired nail pigmented bands were collected and examined. All variables were included in the analysis and examined as possible predictors of nail melanoma. Both univariate and multivariable analyses have been performed. Among 82 cases, 25 were diagnosed as nail melanoma and 57 as benign lesions (including 32 melanocytic nevi and 25 benign melanocytic hyperplasia). Melanoma cases were significantly associated with a width of the pigmented band higher than 2/3 of the nail plate, grey and black colours, irregularly pigmented lines, Hutchinson and micro-Hutchinson signs, and nail dystrophy. Granular pigmentation, a newly defined dermoscopic criterion, was found in 40% of melanomas and only in 3.51% of benign lesions. Dermoscopic examination of longitudinal melanonychia provides useful information that could help clinicians to improve melanoma recognition. © 2016 European Academy of Dermatology and Venereology.

Internal and external dynamics in language: evidence from verb regularity in a historical corpus of English.

PubMed

Cuskley, Christine F; Pugliese, Martina; Castellano, Claudio; Colaiori, Francesca; Loreto, Vittorio; Tria, Francesca

2014-01-01

Human languages are rule governed, but almost invariably these rules have exceptions in the form of irregularities. Since rules in language are efficient and productive, the persistence of irregularity is an anomaly. How does irregularity linger in the face of internal (endogenous) and external (exogenous) pressures to conform to a rule? Here we address this problem by taking a detailed look at simple past tense verbs in the Corpus of Historical American English. The data show that the language is open, with many new verbs entering. At the same time, existing verbs might tend to regularize or irregularize as a consequence of internal dynamics, but overall, the amount of irregularity sustained by the language stays roughly constant over time. Despite continuous vocabulary growth, and presumably, an attendant increase in expressive power, there is no corresponding growth in irregularity. We analyze the set of irregulars, showing they may adhere to a set of minority rules, allowing for increased stability of irregularity over time. These findings contribute to the debate on how language systems become rule governed, and how and why they sustain exceptions to rules, providing insight into the interplay between the emergence and maintenance of rules and exceptions in language.

Internal and External Dynamics in Language: Evidence from Verb Regularity in a Historical Corpus of English

PubMed Central

Cuskley, Christine F.; Pugliese, Martina; Castellano, Claudio; Colaiori, Francesca; Loreto, Vittorio; Tria, Francesca

2014-01-01

Human languages are rule governed, but almost invariably these rules have exceptions in the form of irregularities. Since rules in language are efficient and productive, the persistence of irregularity is an anomaly. How does irregularity linger in the face of internal (endogenous) and external (exogenous) pressures to conform to a rule? Here we address this problem by taking a detailed look at simple past tense verbs in the Corpus of Historical American English. The data show that the language is open, with many new verbs entering. At the same time, existing verbs might tend to regularize or irregularize as a consequence of internal dynamics, but overall, the amount of irregularity sustained by the language stays roughly constant over time. Despite continuous vocabulary growth, and presumably, an attendant increase in expressive power, there is no corresponding growth in irregularity. We analyze the set of irregulars, showing they may adhere to a set of minority rules, allowing for increased stability of irregularity over time. These findings contribute to the debate on how language systems become rule governed, and how and why they sustain exceptions to rules, providing insight into the interplay between the emergence and maintenance of rules and exceptions in language. PMID:25084006

High latitude artificial periodic irregularity observations with the upgraded EISCAT heating facility

NASA Astrophysics Data System (ADS)

Vierinen, Juha; Kero, Antti; Rietveld, Michael T.

2013-12-01

We present a recently developed ionospheric modification experiment that produces artificial periodic irregularities in the ionosphere and uses them to make observations of the spatiotemporal behaviour of the irregularities. In addition, the method can be used to measure Faraday rotation and vertical velocities. We also introduce a novel experiment that allows monitoring the formation of the irregularities during heating, in addition to observing their decay after heating. The first measurements indicate, contrary to existing theory, that the amplitude of the radar echoes from the periodic irregularities grows faster than they decay. We focus on the API effects in the D- and E-region of the ionosphere.

Upper hybrid wave excitation due to O-mode interaction with density gradient in the ionosphere

DOE Office of Scientific and Technical Information (OSTI.GOV)

Antani, S.N.; Kaup, D.J.; Rao, N.N.

1995-12-31

It has been well recognized that upper hybrid (UH) waves play a key role in various wave processes occurring in the upper hybrid resonance (UHR) region of the ionosphere leading to the observed stimulated electromagnetic emissions (SEE) during artificial heating by ordinary mode (O-mode) electromagnetic waves. Hence it is important to investigate how the UH waves get excited from the incident O-mode. It has been generally suggested that the UH waves are excited by O-mode interaction with nonuniform ionospheric plasma. For instance, direct conversion of the O-mode into UH waves due to pre-existing short scale irregularities was reported earlier. Heremore » the authors consider the role of large-scale, smooth density gradient in exciting the UH waves from the O-mode. The model used is that of a driven harmonic oscillator in which the source term arises from the O-mode interaction with local density gradient. For a slab model with density gradient in the x-direction, and the geomagnetic field in the z-direction, they obtain an inhomogeneous fourth order ordinary differential equation governing the UH wave excitation. This equation has been analyzed in the vicinity of the UHR. The pertinent solutions will be presented and discussed for the typical parameters of heating experiments.« less