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Sample records for acute zonal occult

  1. Photoreceptor atrophy in acute zonal occult outer retinopathy

    Zibrandtsen, N.; Munch, I.C.; Klemp, K.;

    2006-01-01

    Purpose: To assess retinal morphology in acute zonal occult outer retinopathy (AZOOR). Methods: Three patients with a normal ophthalmoscopic fundus appearance, a history of photopsia, and visual field loss compatible with AZOOR were examined using optical coherence tomography, automated perimetry...

  2. Acute Zonal Occult Outer Retinopathy with Atypical Findings

    Dimitrios Karagiannis

    2014-01-01

    Full Text Available Background. To report a case of acute zonal occult outer retinopathy (AZOOR with atypical electrophysiology findings. Case Presentation. A 23-year-old-female presented with visual acuity deterioration in her right eye accompanied by photopsia bilaterally. Corrected distance visual acuity at presentation was 20/50 in the right eye and 20/20 in the left eye. Fundus examination was unremarkable. Visual field (VF testing revealed a large scotoma. Pattern and full-field electroretinograms (PERG and ERG revealed macular involvement associated with generalized retinal dysfunction. Electrooculogram (EOG light rise and the Arden ratio were within normal limits bilaterally. The patient was diagnosed with AZOOR due to clinical findings, visual field defect, and ERG findings. Conclusion. This is a case of AZOOR with characteristic VF defects and clinical symptoms presenting with atypical EOG findings.

  3. Acute progression of electrophysiologically affected fellow eye in unilaterally symptomatic acute zonal occult outer retinopathy

    Iriyama A

    2011-08-01

    Full Text Available Kayo Kure, Ryo Obata, Yuji Inoue, Aya Iriyama, Yasuo YanagiDepartment of Ophthalmology, University of Tokyo School of Medicine, Tokyo, JapanAbstract: Some patients with acute zonal occult outer retinopathy (AZOOR show symptomatic acute visual impairment in one eye only, but electrophysiological abnormalities in both eyes. A 46-year-old female who had noticed paracentral scotoma of her right eye six months previously was referred to our hospital. At initial examination, her best-corrected visual acuity was 0.7 in the right eye and 1.2 in the left. Whereas the full-field rod electroretinogram (ERG was normal in both eyes, the cone response was nonrecordable in the right eye and showed a significant decrease in amplitude in the left eye. The 30 Hz flicker ERG showed similar results. Multifocal ERG was nonrecordable in the right eye and showed a residual response in only the central part of the left. Fourteen months after the first visit, the patient presented complaining of acute visual acuity loss in the left eye. Visual acuity in her left eye had decreased to 0.01. The multifocal ERG was nonrecordable. Although the patient chose oral prednisolone therapy, only limited recovery was observed in the patient. Even if only the ERG shows changes and there are no other symptoms, ophthalmologists should continue observation in view of the possibility of an acute exacerbation.Keywords: acute zonal occult outer retinopathy, electroretinogram, scotoma

  4. Fungal Infection in Patients with Serpiginous Choroiditis or Acute Zonal Occult Outer Retinopathy▿

    Pisa, Diana; Ramos, Marta; García, Patricia; Escoto, Remberto; Barraquer, Rafael; Molina, Susana; Carrasco, Luis

    2007-01-01

    The etiologies of a number of retinopathies, including serpiginous choroiditis and acute zonal occult outer retinopathy (AZOOR), remain uncertain. Recently, we provided evidence that AZOOR is caused by Candida famata infection. The purpose of this article was to investigate the presence of fungal infection in five patients affected with serpiginous choroiditis and five patients with diagnosis of AZOOR. To assess the presence of fungal infection the presence of antibodies in human serum sample...

  5. Deriving Saturn's Zonal Winds from Cassini Radio Occultations

    Flasar, F. Michael; Schinder, Paul J.

    2015-11-01

    Tracking cloud features from visible images have provided detailed maps of the meridional variation of the mean zonal winds on the giant planets, including Saturn. Filters at different wavelengths can provide information on the vertical structure of the zonal winds, but that is approximate, and the altitudes of winds observed with a given filter generally vary with location, because cloud heights do. Radio occultations provide vertical profiles of refractivity, pressure, and temperature vs. altitude. Zonal winds can be derived from the assumption of gradient wind balance, which relates the zonal wind to the change of geopotential height with latitude along an isobar. Occultations have the advantage that vertical profiles of winds can be obtained in the troposphere and stratosphere. There are, however, complicating factors. In general, the meridional distribution of occultation soundings is limited and unevenly distributed. Moreover, one needs to know the geometry of the occulting atmosphere to correctly account for the path of the refracted radio signal. The zonal winds matter, because they distort isobaric surfaces. For example, an inversion that includes Saturn's oblateness from uniform rotation, based on the Voyager System III period, would yield equatorial temperature profiles that are shifted by ~ 2 K relative to one that also includes the differential rotation associated with the cloud-tracked zonal winds. In retrieving vertical profiles of atmospheric variables from occultation soundings, one also needs an additional symmetry assumption to make the inversions tractable. Typically one uses the zonal winds based on cloud-tracking studies, and assumes they are axisymmetric and barotropic, so that both the gravitational and centrifugal forces are derivable from a potential, and the surfaces of constant geopotential height, pressure, and temperature coincide. This forms the basis for an iterative approach. The pressures and temperatures so retrieved from the

  6. A New Look at Titan's Zonal Winds from Cassini Radio Occultations

    Flasar, F. M.; Schinder, P. J.

    2012-01-01

    We use the existing thirteen Cassini radio'occultation soundings to construct a meridional cross section of geopotential height vs. pressure and latitude. The assumption of balanced flow permits the construction of a similar cross section of zonal winds, from near the surface to the 0.1'mbar level. In the lower troposphere, the winds are approx.10 m/s, except within 20deg of the equator, where they are much smaller. The winds increase higher up in the troposphere to nearly 40 m/s in the tropopause region, but then decay rapidly in the lower stratosphere to near'zero values at 20 mbar (approx.80 km), reminiscent of the Huygens Doppler Wind Experiment result. This null zone extends over most latitudes, except for limited bands at mid'latitudes. Higher up in the stratosphere, the winds become larger. They are highest in the northern (winter) hemisphere. We compare the occultation results with the DWE and CIRS retrievals and discuss the similarities and differences among the data sets.

  7. Photoreceptor atrophy in acute zonal occult outer retinopathy

    Zibrandtsen, N.; Munch, I.C.; Klemp, K.;

    2008-01-01

    examined using optical coherence tomography (OCT), automated perimetry and electroretinography (ERG). Both patients demonstrated photoreceptor atrophy corresponding to partial or complete scotomata with reduced or extinct electroretinographic responses. Attenuation or complete loss of all the segments...... composing the photoreceptor layer was found by OCT. Full-field ERG revealed affection of the 30 Hz flicker responses and subnormal photopic responses in both patients and subnormal scotopic responses in case 1. Multifocal electroretinography (mERG) revealed localized outer retinal dysfunction. The field...

  8. Photoreceptor atrophy in acute zonal occult outer retinopathy

    Zibrandtsen, N.; Munch, I.C.; Klemp, K.;

    2008-01-01

    appearance were examined using optical coherence tomography (OCT), automated perimetry and electroretinography (ERG). RESULTS: Both patients demonstrated photoreceptor atrophy corresponding to partial or complete scotomata with reduced or extinct electroretinographic responses. Attenuation or complete loss...... of all the segments composing the photoreceptor layer was found by OCT. Full-field ERG revealed affection of the 30 Hz flicker responses and subnormal photopic responses in both patients and subnormal scotopic responses in case 1. Multifocal electroretinography (mERG) revealed localized outer retinal...

  9. 膝部急性隐匿性骨损伤的MRI评价%Evaluation of acute occult bone injuries of the knee with MRI

    郑少锐; 李润根

    2011-01-01

    Objective : To evaluate MRI in the diagnosis of acute occult bone injury of the knee. Methods : The MR images of 113 patients mct the criteria acute occuit bone injuries of knee. Mink's knee occult bone injury classification was used for the study. Results : Of the 113 patients.there were bone contusion (71 cases) ,bone cartilage injury (25 cases) and occult fracture ( 15 cases) , stress fracture ( 2 cases). MRI manifestations of these injuries varied , yet the signal characteristics were more consistent and were better shown on T1 WI and STIR. Conclusion: MRI is superior to radiography and CT in the diagnosis of acute occult bone injury of knee,which is a reliable technique in clinical practice.%目的:评价MRI对膝部急性隐匿性骨损伤的诊断价值.方法:回顾性分析113例符合纳入条件的急性膝部创伤患者的MRI图像,采用Mink膝部隐匿性骨损伤分类方法进行观察.结果:骨挫伤71例,骨软骨损伤25例,隐匿骨折15例,应力骨折2例.这些损伤的MRI表现形态各异,信号特点较为一致,以T1WI和STIR显示较好.结论:MRI在膝部急性隐匿性骨损伤检查中,较X线、CT检查具有明显优势和可靠的临床应用价值.

  10. Utilization of fecal occult blood test in the acute hospital setting and its impact on clinical management and outcomes

    Mosadeghi, S; Ren, H; Catungal, J; Yen, I; Liu, B; Wong, RJ; Bhuket, T

    2016-01-01

    Background: Despite lack of evidence supporting the use of fecal occult blood test (FOBT) in the acute hospital setting, FOBT is commonly used in the inpatient setting for reasons other than colorectal cancer (CRC) screening. Aims: To evaluate practice trends in utilizing FOBT on inpatients and its impact on affecting clinical management and outcomes. Materials and Methods: A cross-sectional study of consecutive adult patients undergoing FOBT from January 1, 2011 to December 31, 2011 during an acute medical admission at a large urban safety net hospital was performed. Indications for FOBT, and the impact of FOBT results on endoscopic procedures performed and clinical outcomes were assessed. The number of inpatient endoscopic procedures before and after discontinuing inpatient FOBT was also assessed. Results: A total of 207 inpatient FOBTs were performed in 2011. The most common reason cited for FOBT was anemia (36%, n = 74) followed by gastrointestinal (GI) bleeding (27%, n = 55). Interestingly, 23% (n = 47) of the patients undergoing inpatient FOBT had overt GI bleeding. As expected, patients with positive FOBT were significantly more likely to undergo endoscopic examinations (P < 0.01). After discontinuing the availability of inpatient FOBT, patients were less likely to undergo endoscopic examinations [odds ratio (OR) 0.80, 95% confidence interval (CI) 0.75-0.85]. Conclusion: Inappropriate utilization of FOBT in the inpatient setting is common, even when the indication does not support its use. Setting limitations on inpatient FOBT may reduce the inappropriate utilization of inpatient FOBT. Quality improvement initiatives are needed to educate clinicians on the appropriate use of FOBT, which is primarily for average risk CRC screening. PMID:27089107

  11. Utilization of fecal occult blood test in the acute hospital setting and its impact on clinical management and outcomes

    S Mosadeghi

    2016-01-01

    Full Text Available Background: Despite lack of evidence supporting the use of fecal occult blood test (FOBT in the acute hospital setting, FOBT is commonly used in the inpatient setting for reasons other than colorectal cancer (CRC screening. Aims: To evaluate practice trends in utilizing FOBT on inpatients and its impact on affecting clinical management and outcomes. Materials and Methods: A cross-sectional study of consecutive adult patients undergoing FOBT from January 1, 2011 to December 31, 2011 during an acute medical admission at a large urban safety net hospital was performed. Indications for FOBT, and the impact of FOBT results on endoscopic procedures performed and clinical outcomes were assessed. The number of inpatient endoscopic procedures before and after discontinuing inpatient FOBT was also assessed. Results: A total of 207 inpatient FOBTs were performed in 2011. The most common reason cited for FOBT was anemia (36%, n = 74 followed by gastrointestinal (GI bleeding (27%, n = 55. Interestingly, 23% (n = 47 of the patients undergoing inpatient FOBT had overt GI bleeding. As expected, patients with positive FOBT were significantly more likely to undergo endoscopic examinations (P < 0.01. After discontinuing the availability of inpatient FOBT, patients were less likely to undergo endoscopic examinations [odds ratio (OR 0.80, 95% confidence interval (CI 0.75-0.85]. Conclusion: Inappropriate utilization of FOBT in the inpatient setting is common, even when the indication does not support its use. Setting limitations on inpatient FOBT may reduce the inappropriate utilization of inpatient FOBT. Quality improvement initiatives are needed to educate clinicians on the appropriate use of FOBT, which is primarily for average risk CRC screening.

  12. Review of zonal flows

    A comprehensive review of zonal flow phenomena in plasmas is presented. While the emphasis is on zonal flows in laboratory plasmas, zonal flows in nature are discussed as well. The review presents the status of theory, numerical simulation and experiments relevant to zonal flows. The emphasis is on developing an integrated understanding of the dynamics of drift wave - zonal flow turbulence by combining detailed studies of the generation of zonal flows by drift waves, the back-interaction of zonal flows on the drift waves, and the various feedback loops by which the system regulates and organizes itself. The implications of zonal flow phenomena for confinement in, and the phenomena of fusion devices are discussed. Special attention is given to the comparison of experiment with theory and to identifying direction for progress in future research. (author)

  13. Physics of zonal flows

    Zonal flows, which means azimuthally symmetric band-like shear flows, are ubiquitous phenomena in nature and the laboratory. It is now widely recognized that zonal flows are a key constituent in virtually all cases and regimes of drift wave turbulence, indeed, so much so that this classic problem is now frequently referred to as ''drift wave-zonal flow turbulence.'' In this review, new viewpoints and unifying concepts are presented, which facilitate understanding of zonal flow physics, via theory, computation and their confrontation with the results of laboratory experiment. Special emphasis is placed on identifying avenues for further progress. (author)

  14. Physics of Zonal Flows

    Itoh, Kimitaka

    2005-10-01

    This talk describes an overview of zonal flow physics, covering the theory, simulation and experiment. The zonal flows are excited nonlinearly by drift wave fluctuations, and suppress the turbulence and transport, so as to realize a self-regulating state for turbulence and mesoscale structure. This recognition is the central of recent paradigm shift in plasma physics, i.e., the preceding linear, local and deterministic pictures of instability and transport have been taken over by the new nonlinear, nonlocal (in real and wavenumber spaces) and statistical pictures of them. The zonal flow phenomenon, i.e., the global axial vector fields are generated by the release of global free energy in scalar fields through exciting turbulence, is a typical example of the fundamental issues in modern physics. In this review, the progresses made by theory and simulations, such as the linear damping rate, nonlinear mechanisms for growth and saturation, law of energy partition between turbulence and flow, life time of zonal flow, and so on, are explained. The transport by drift wave fluctuations, which are dressed by zonal flows, is discussed. Then experimental observations and verifications, which have been piled up rapidly in basic plasma experiments and confinement research, are explained, highlighting the integration with theory and simulation. Generalization to include magnetic field (zonal field) is addressed, in the light of the study of dynamo. Zonal flows in both laboratory and planetary-solar circumstances are discussed as well. This presentation illustrates the fast evolution of the physics of turbulence and structure formation of plasmas in the nature and laboratory. In collaboration with S.-I. Itoh, P. H. Diamond, T. S. Hahm, A. Fujisawa, G. R. Tynan and M. Yagi.

  15. MR imaging of occult fractures

    Objective: To investigate the value of MR imaging in detecting occult fractures. Methods: Sixteen cases with acute trauma were studied using radiography and MR imaging, three cases also underwent CT examinations. Three fractures occurred in the femur condyle, 8 in the proximal tibia and 5 in the thoracolumbar spine. Results: All sixteen cases had normal radiographic results. In 11 cases with femur condyle and tibia occult fracture, MR imaging demonstrated linear low signal in the subcortical region in 3 cases and irregular low signal from articular faces to shaft in 8 cases on both T1WI and T2WI, and high signal changes around low signal were seen on T2WI, and the width of low signal was less than 4 mm on both T1WI and T2WI. The high signal in T1 weighted-Fat saturated sequence was more remarkable and wider than that on T2WI. 3 cases with CT scanning showed no fracture signs. In five cases with thoracolumbar vertebral occult fractures, MR imaging demonstrated horizontal linear low signal in the center of vertebra on both T1WI and T2WI, and high signal changes around low signal were seen on T2WI. Conclusions: MR imaging could early determine the diagnosis of occult fractures. MRI should be the next examination of choice when plain films fail to reveal suspected fractures in the setting of suggestive symptoms and positive physical examination

  16. The Occult Today: Why?

    Kessler, Gary E.

    1975-01-01

    Author offered some reflections on the "why" of the contemporary interest in the occult. He attempted to convince the reader that, if he or she has been surprised by the recent rise of occultism, sober reflection will dispell some fears and, perhaps, even convince him or her that occultism is not merely superstition. (Author/RK)

  17. Ozone zonal asymmetry and planetary wave characterization during Antarctic spring

    I. Ialongo

    2012-03-01

    Full Text Available A large zonal asymmetry of ozone has been observed over Antarctica during winter-spring, when the ozone hole develops. It is caused by a planetary wave-driven displacement of the polar vortex. The total ozone data by OMI (Ozone Monitoring Instrument and the ozone profiles by MLS (Microwave Limb Sounder and GOMOS (Global Ozone Monitoring by Occultation of Stars were analysed to characterize the ozone zonal asymmetry and the wave activity during Antarctic spring. Both total ozone and profile data have shown a persistent zonal asymmetry over the last years, which is usually observed from September to mid-December. The largest amplitudes of planetary waves at 65° S (the perturbations can achieve up to 50% of zonal mean values is observed in October. The wave activity is dominated by the quasi-stationary wave 1 component, while the wave 2 is mainly an eastward travelling wave. Wave numbers 1 and 2 generally explain more than the 90% of the ozone longitudinal variations. Both GOMOS and MLS ozone profile data show that ozone zonal asymmetry covers the whole stratosphere and extends up to the altitudes of 60–65 km. The wave amplitudes in ozone mixing ratio decay with altitude, with maxima (up to 50% below 30 km.

    The characterization of the ozone zonal asymmetry has become important in the climate research. The inclusion of the polar zonal asymmetry in the climate models is essential for an accurate estimation of the future temperature trends. This information might also be important for retrieval algorithms that rely on ozone a priori information.

  18. Overview of zonal flow physics

    Zonal flows, by which we mean azimuthally symmetric band-like shear flows, are ubiquitous phenomena in nature and the laboratory. It is now widely recognized that zonal flows are a key constituent in virtually all cases and regimes of drift wave turbulence, indeed, so much so that this classic problem is now frequently referred to as 'drift wave-zonal flow turbulence'. In this theory overview, we present new viewpoints and unifying concepts which facilitate understanding of zonal flow physics, via theory, computation and their confrontation with the results of laboratory experiment. Special emphasis is placed on identifying avenues for further progress. (author)

  19. Deep shadow occulter

    Cash, Webster (Inventor)

    2010-01-01

    Methods and apparatus are disclosed for occulting light. The occulter shape suppresses diffraction at any given size or angle and is practical to build because it can be made binary to avoid scatter. Binary structures may be fully opaque or fully transmitting at specific points. The diffraction suppression is spectrally broad so that it may be used with incoherent white light. An occulter may also include substantially opaque inner portion and an at least partially transparent outer portion. Such occulters may be used on the ground to create a deep shadow in a short distance, or may be used in space to suppress starlight and reveal exoplanets.

  20. Zonal flows and pattern formation

    The general aspects of zonal flow physics, their formation, damping and interplay with quasi two dimensional turbulence are explained in the context of magnetized plasmas and quasi-geostrophic fluids with an emphasis on formation and selection of spatial patterns. General features of zonal flows as they appear in planetary atmospheres, rotating convection experiments and fusion plasmas are reviewed. Detailed mechanisms for excitation and damping of zonal flows, and their effect on turbulence via shear decorrelation is discussed. Recent results on nonlocality and staircase formation are outlined. (topical review)

  1. Patient with hepatocellular carcinoma related to prior acute arsenic intoxication and occult HBV: epidemiological, clinical and therapeutic results after 14 years of follow-up

    Casanovas-Taltavull, Teresa; Ribes, Josepa; Berrozpe, Ana; Jordan, Sara; Casanova, Aurora; Sancho, Concha; Valls, Carles; Bosch, F. Xavier

    2006-01-01

    Little is known about the long-term survivors of acute arsenic intoxication. We present here a clinical case report of a man with chronic hepatitis B virus (HBV) infection who developed hepatocellular carcinoma four years after acute arsenic poisoning. HBsAg was detected in serum in 1990 when he voluntarily donated blood. In 1991, the patient suffered from severe psychological depression that led him to attempt suicide by massive ingestion of an arsenic-containing rodenticide. He survived wit...

  2. Angiographically occult arteriovenous malformations causing intracerebral hemorrhage

    We had experienced 5 cases of angiographically occult AVMs led to intracerebral hemorrhage and progressive neurologic deficit and seizure. Cerebral angiography in each case failed to demonstrate the vascular nature of the lesion and conventional skull radiography was no use. Computed tomography (CT), in 4 cases out of 5, showed well demarcated, slightly hyperdense and ovoid masses which turned out resolving hematomas. These lesions had also contained focal areas of high densities. In one case we observed definitively enhanced area in the resolving hematoma and it was corresponded to histopathologically proved AVM. CT appearance of acute hemorrhage at the subcortical region of cerebral hemisphere was showed in another case. We believe that CT can afford important supplementary information regarding an associated hematoma for angiographically occult AVM. Caution is advised in assuming that angiographically avascular lesion demonstrable by CT is not vascular malformation.

  3. Zonal flows as statistical equilibria

    Bouchet, F

    2016-01-01

    Zonal jets are striking and beautiful examples of the propensity for geophysical turbulent flows to spontaneously self-organize into robust, large scale coherent structures. There exist many dynamical mechanisms for the formation of zonal jets: statistical theories (kinetic approaches, second order or larger oder closures), deterministic approaches (modulational instability, $\\beta$-plumes, radiating instability, zonostrophic turbulence, and so on). A striking remark is that all these different dynamical approaches, each of them possibly relevant in some specific regimes, lead to the same kind of final jet structures. Is it then possible to have a more general explanation of why all these different dynamical regimes, from fully turbulent flows to gentle quasilinear regime, consistently lead to the same jet attractors ? Equilibrium statistical mechanics provides an answer to this general question. Here we we present the salient features of this theory and review applications of this approach to the description...

  4. Venous thromboembolism and occult cancer: impact on clinical practice.

    Gheshmy, Afshan; Carrier, Marc

    2016-04-01

    Unprovoked venous thromboembolism (VTE) can be the first manifestation of cancer. Given this relationship between unprovoked VTE and cancer, it is appealing for clinicians to screen their patients with a first episode of acute unprovoked VTE for a potential occult malignancy. Five different studies have compared a limited (thorough history and physical exam, basic bloodwork) to a more extensive occult cancer screening strategy (e.g. computed tomography, fludeoxyglucose positron emission tomography, etc.). Most of these studies have failed to show that an extensive occult cancer screening strategy diagnoses more occult cancer (including early cancers), misses fewer cancers during follow-up or improves overall and/or cancer-related mortality suggesting that extensive occult cancer screening should not be performed routinely. Therefore, patients with a first unprovoked VTE should undergo a limited cancer screening only and clinicians should ensure that their patients are up to date regarding age- and gender- specific cancer screening (colon, breast, cervix and prostate) as per their national recommendations. Current evidence does not support a net clinical benefit to perform an extensive occult cancer screening on all patients, and a decision to do additional testing should be made on a case by case basis. PMID:27067984

  5. The occult abscess

    The clinical signs of an abscess may be masked by the patient's immunosuppressed state or antibiotic therapy. The authors reviewed the clinical presentations of 30 patients with 32 occult abscesses diagnosed with CT or US over 4 years. The abscesses included 12 intraperitoneal, 16 retroperitoneal, and four pleural infected fluid collections. Initial symptoms included fever of unknown origin in six patients and musculoskeletal complaints in four. Six patients were diagnosed with noninflammatory medical problems, five were under investigation for tumor, and, while an infectious process was suspected in nine patients, an associated abscess was not. The occult abscess may mimic other disease processes, and the radiological may be the first to suggest the diagnosis in patients in whom the classic signs and symptoms are absent

  6. GAMBARAN RADIOLOGIS PADA OCCULT PNEUMOTHORAKS

    Putu Aditha Satya Putra; Nyoman Srie Laksminingsih

    2013-01-01

    Pneumothorax is a recognized cause of death in chest wall trauma. Radiological examination is the key factor to establish the existence of a pneumothorax. Occult pneumothorax is pneumothorax that undiagnosed clinically and with thoracic x-ray, but it can be tolerated while other more urgent trauma. Occult pneumothorax can be detected by CT (Computed tomography). Occult pneumothorax may progress to tension pneumothorax in certain circumstances. Missing in diagnosed pneumothorax will cause deat...

  7. Patient with hepatocellular carcinoma related to prior acute arsenic intoxication and occult HBV: Epidemiological, clinical and therapeutic results after 14 years of follow-up

    Casanovas-Taltavull, Teresa; Ribes, Josepa; Berrozpe, Ana; Jordan, Sara; Casanova, Aurora; Sancho, Concha; Valls, Carles; Bosch, F Xavier

    2006-01-01

    Little is known about the long-term survivors of acute arsenic intoxication. We present here a clinical case report of a man with chronic hepatitis B virus (HBV) infection who developed hepatocellular carcinoma four years after acute arsenic poisoning. HBsAg was detected in serum in 1990 when he voluntarily donated blood. In 1991, the patient suffered from severe psychological depression that led him to attempt suicide by massive ingestion of an arsenic-containing rodenticide. He survived with polyneuropathy and paralysis of the lower limbs, and has been wheelchair-bound since then. During participation in a follow-up study conducted among HBV carriers, abdominal ultrasound detected a two-centimeter liver mass consistent with hepatocellular carcinoma. The tumor was confirmed by computed tomography (CT) and magnetic resonance image (MRI). Because of his significant comorbidity, the patient received palliative treatment with transarterial lipiodol chemoembolization (TACE) on three occasions (1996, 1997 and 1999). At his most recent visit in May 2005, the patient was asymptomatic, liver enzymes were normal and the tumor was in remission on ultrasound. PMID:16610011

  8. Magellan radio occultation measurements of atmospheric waves on Venus

    Hinson, David P.; Jenkins, J. M.

    1995-01-01

    Radio occultation experiments were conducted at Venus on three consecutive orbits of the Magellan spacecraft in October 1991. Each occultation occurred over the same topography (67 deg N, 127 deg E) and at the same local time (22 hr 5 min), but the data are sensitive to zonal variations because the atmosphere rotates significantly during one orbit. Through comparisons between observations and predictions of standard wave theory, we have demonstrated that small-scale oscillations in retrieved temperature profiles as well as scintillations in received signal intensity are caused by a spectrum of vertically propagating internal gravity waves. There is a strong similarity between the intensity scintillations observed here and previous measurements, which pertain to a wide range of locations and experiment dates. This implies that the same basic phenomenon underlies all the observations and hence that gravity waves are a persistent, global feature of Venus' atmosphere. We obtained a fairly complete characterization of a gravity wave that appears above the middle cloud in temperature measurements on all three orbits. The amplitude and vertical wavelength are about 4 K and 2.5 km respectively, at 65 km. A model for radiative damping implies that the wave intrinsic frequency is approximately 2 x 10(exp 4) rad/sec, the corresponding ratio between horizontal and vertical wavelengths is approximately 100. The wave is nearly stationary relative to the surface or the Sun. Radiative attenuation limits the wave amplitude at altitudes above approximately 65 km, leading to wave drag on the mean zonal winds of about +0.4 m/sec per day (eastward). The sign, magnitude, and location of this forcing suggest a possible role in explaining the decrease with height in the zonal wind speed that is believed to occur above the cloud tops. Temperature oscillations with larger vertical wavelengths (5-10 km) were also observed on all three orbits, but we are able unable to interpret these

  9. Zonal displacement of western Pacific warm pool and zonal wind anomaly over the Pacific Ocean

    2007-01-01

    The thermal condition anomaly of the western Pacific warm pool and its zonal displacement have very important influences on climate change in East Asia and even the whole world.However, the impact of the zonal wind anomaly over the Pacific Ocean on zonal displacement of the warm pool has not yet been analyzed based on long-term record. Therefore, it is important to study the zonal displacement of the warm pool and its response to the zonal wind anomaly over the equatorial Pacific Ocean. Based on the NCDC monthly averaged SST (sea surface temperature) data in 2°×2° grid in the Pacific Ocean from 1950 to 2000, and the NCEP/NCAR global monthly averaged 850 hPa zonal wind data from 1949 to 2000, the relationships between zonal displacements of the western Pacific warm pool and zonal wind anomalies over the tropical Pacific Ocean are analyzed in this paper. The results show that the zonal displacements are closely related to the zonal wind anomalies over the western, central and eastern equatorial Pacific Ocean. Composite analysis indicates that during ENSO events, the warm pool displacement was trigged by the zonal wind anomalies over the western equatorial Pacific Ocean in early stage and the process proceeded under the zonal wind anomalies over the central and eastern equatorial Pacific Ocean unless the wind direction changes. Therefore, in addition to the zonal wind anomaly over the western Pacific, the zonal wind anomalies over the central and eastern Pacific Ocean should be considered also in investigation the dynamical mechanisms of the zonal displacement of the warm pool.

  10. The Halogen Occultation Experiment

    Russell, James M., III; Gordley, Larry L.; Park, Jae H.; Drayson, S. R.; Hesketh, W. D.; Cicerone, Ralph J.; Tuck, Adrian F.; Frederick, John E.; Harries, John E.; Crutzen, Paul J.

    1993-01-01

    The Halogen Occultation Experiment (HALOE) uses solar occultation to measure vertical profiles of O3, HCl, HF, CH4, H2O, NO, NO2, aerosol extinction, and temperature versus pressure with an instantaneous vertical field of view of 1.6 km at the earth limb. Latitudinal coverage is from 80 deg S to 80 deg N over the course of 1 year and includes extensive observations of the Antarctic region during spring. The altitude range of the measurements extends from about 15 km to about 60-130 km, depending on channel. Experiment operations have been essentially flawless, and all performance criteria either meet or exceed specifications. Internal data consistency checks, comparisons with correlative measurements, and qualitative comparisons with 1985 atmospheric trace molecule spectroscopy (ATMOS) results are in good agreement. Examples of pressure versus latitude cross sections and a global orthographic projection for the September 21 to October 15, 1992, period show the utility of CH4, HF, and H2O as tracers, the occurrence of dehydration in the Antarctic lower stratosphere, the presence of the water vapor hygropause in the tropics, evidence of Antarctic air in the tropics, the influence of Hadley tropical upwelling, and the first global distribution of HCl, HF, and NO throughout the stratosphere. Nitric oxide measurements extend through the lower thermosphere.

  11. Model of intermittent zonal flow structure formation

    We present a theory the PDF tails of the zonal flow formation by assuming that a modon (a bipolar vortex) drives a zonal flow through the generalized Reynolds stress. We show that the PDF tails of zonal flow formation have exponential behavior ≅e-ξφZF3, with the overall amplitude ξ severely quenched by strong flow shear. It is found that stronger zonal flows are generated in ITG turbulence than Hasegawa-Mima (HM) turbulence as well as further from marginal stability. This suggests that although ITG turbulence has a higher level of heat flux, it also more likely generates stronger zonal flows, leading to a self-regulating system. It is also shown that shear flows can significantly reduce the PDF tails of structure formation.

  12. The Occult: Diabolica to Alchemists

    Delaney, Oliver J.

    1971-01-01

    The 91 items in this bibliography deal with works of occult science. The material is subdivided into biographies, dictionaries, encyclopedias, handbooks, noteworthy histories, indices, annuals, and a few miscellany works with treatises. (95 references) (Author)

  13. Sporadic E Morphology from GPS-CHAMP Radio Occultation

    Wu, Dong L.; Ao, Chi O.; Hajj, George A.; de la Torre Juarez, Manuel; Mannucci, Anthony J.

    2005-01-01

    The scintillations of phase and amplitude in terms of signal-to-noise ratio (SNR) of the GPS radio occultation signal are caused by thin ionization layers. These thin irregular electron density layers in the E region ionosphere are often called sporadic E (Es). For a monthly retrieval of Es morphology we use the variances of the phase and SNR fluctuations of worldwide 6000 GPS/CHAMP occultations in the E region. The Es climatology is studied globally with the SNR and phase variances in terms of monthly zonal means, seasonal maps, and diurnal and long-term variations. The zonal mean variances reveal strong, extended Es activities at summertime midlatitudes but weak, confined activities in wintertime high latitudes, peaking at 105 km. Global maps at 105-km altitude show clear dependence of Es activities on the geomagnetic dip angle, where the summertime midlatitude Es occurs mostly at dip angles of 30 deg. - 60 deg. and the wintertime high-latitude enhancement occurs mostly at dip angles greater than 80 deg. The midlatitude Es variances exhibit a strong semidiurnal variation with peak hours near 0800 1000 and 2000 local solar time, respectively. The peak hours are delayed slightly with decreasing height, suggesting influences from the semidiurnal tide. To provide more insights on the observed SNR and phase variances, we model radio wave propagation for the CHAMP observing geometry under several perturbed cases in the E region ionosphere. The model simulations indicate that the SNR variance has the maximum response to Es perturbations at vertical wavelengths of 1.2 km, whereas the phase response maximizes at 2 km (for the 1-s variance analysis). The characteristic scale depends little on the truncation time used in the SNR variance analysis, but it increases with the truncation time for the phase variances. Initial studies show that reasonable global Es morphology can be produced on a monthly and seasonal basis with the CHAMP one-antenna occultations. Better results

  14. Fixed transmission rights for zonal congestion management

    Declaring that engineering studies and experience are the criteria to defining zonal boundaries, or to define a zone based on the fact that it is a densely interconnected area and paths connecting these densely interconnected areas are interzonal lines, will render insufficient and fuzzy definitions. The zone definition is given a certain criterion based on the locational marginal price (LMP). This concept is used to define zonal boundaries and to decide whether any zone should be merged with another zone or split into new zones. The paper combines zonal and fixed transmission rights (FTR) schemes to manage congestion. This combined scheme is utilised with LMPs to define zonal boundaries more appropriately. The scheme presented gains the best features of the FTR scheme, which are providing financial certainty, maximising the efficient use of the system and making users pay for the actual use of congested paths. (author)

  15. Dynamics of zonal flows in helical systems

    Theory for describing collisionless long-time behavior of zonal flows in helical systems is presented and its validity is verified by gyrokinetic-Vlasov simulation. It is shown that, under the influence of particles trapped in helical ripples, the response of zonal flows to a given source becomes weaker for longer radial wave numbers and deeper helical ripples while a high-level zonal-flow response, which is not affected by helical-ripple-trapped particles, can be maintained for a longer time by reducing their bounce-averaged radial drift velocity. This implies a possibility that helical configurations optimized for reducing neoclassical ripple transport can simultaneously enhance zonal flows which lower anomalous transport. (author)

  16. Coherent Structure of Zonal Flow and Nonlinear Saturation

    K. Itoh; Hallatschek, K.; Toda, S.; Sanuki, H.; Itoh, S.-I.

    2003-01-01

    Nonlinear structure of the zonal flow in toroidal plasma is investigated. It is found that the turbulent drive of zonal flow starts to decrease at high velocity shear of zonal flow. By this mechanism, the zonal flow evolves into a stable stationary structure in turbulent plasmas. Flow velocity and radial scale length are obtained. Analytic model explains simulational observations.

  17. The IMACS Occultation Survey

    Payne, Matthew John; Holman, Matthew; Alcock, Charles; Osip, David; Schlichting, Hilke

    2015-11-01

    We report the results of our extended campaign to search for occultations of background stars by small (sub-km) Kuiper belt objects (KBOs) using the IMACS instrument on the Magellan Telescope.We implemented a novel shutterless continuous readout mode on the IMACS instrument, with custom-made aperture masks, permitting simultaneous high-speed (~40 Hz) photometry for numerous stars, while minimizing the effects of stellar crowding and sky background. Observing in the southern hemisphere allows us to target the intersection of the ecliptic and galactic planes, where hundreds of stars can be monitored with a single field of view.We observed for a total of ~28 hours spread over eight nights, obtaining over 10,000 star-hours of light curves with per-point SNR > 10. This represents an order of magnitude increase in star hours compared to the previous best ground-based survey by Bianco et al. (2009). Our results allow us to place strong constraints on the surface density of sub-km objects in the Kuiper-Belt, as well as to complement the HST FGS results of Schlichting et al. (2009, 2012).

  18. Home Use Tests: Fecal Occult Blood

    ... Procedures In Vitro Diagnostics Home Use Tests Fecal Occult Blood Share Tweet Linkedin Pin it More sharing ... test kit to measure the presence of hidden (occult) blood in your stool (feces). What is fecal ...

  19. Occult Participation: Its Impact on Adolescent Development.

    Tennant-Clark, Cynthia M.; And Others

    1989-01-01

    Investigated relationship between occult participation, substance abuse, and level of self-esteem among 25 clinical (alcohol or drug treatment) and 25 nonclinical adolescents. Results indicated that adolescent substance abuse and occult participation were significantly related. Found significant differences between high versus low occult groups…

  20. MRI of radiographically occult ischial apophyseal avulsions

    Meyers, Arthur B. [Cincinnati Children' s Hospital Medical Center, Department of Radiology, MLC 5031, Cincinnati, OH (United States); Children' s Hospital of Wisconsin, Milwaukee, WI (United States); Laor, Tal; Zbojniewicz, Andrew M.; Anton, Christopher G. [Cincinnati Children' s Hospital Medical Center, Department of Radiology, MLC 5031, Cincinnati, OH (United States)

    2012-11-15

    Acute avulsions of unossified ischial apophyses in children may go undetected on radiography. Therapy includes rest and rehabilitation; however, substantial displacement may require surgery. Our purpose is to illustrate the utility of MRI in the detection of these radiographically occult injuries in skeletally immature children. This retrospective study of more than 5 years included children with ischial avulsions who were evaluated with both radiography and MRI within 3 weeks of acute injury. Initially, radiographs were reviewed to identify those children with unossified ischial apophyses. Subsequently, their MRI examinations were assessed for physeal disruption, bone/soft tissue edema, periosteal/perichondrial elevation and disruption. Initial and follow-up radiographs (if available) were reviewed. Patient age, symptoms and offending activity were determined from clinical records. Five children met inclusion criteria. All initial radiographs were normal. MRI showed: edema (n = 5), periosteal elevation (n = 4), periosteal/perichondrial disruption (n = 4), >5.5 mm displacement (n = 0). Follow-up radiographs in two children (2 and 2.5 months from MRI) showed osseous ischial irregularity. The apophyses remained unossified. Acute unossified ischial apophyseal avulsions in children may be radiographically undetected. In the setting of correlative clinical symptoms, MRI can be used to identify these injuries and to help direct appropriate therapy. (orig.)

  1. MRI of radiographically occult ischial apophyseal avulsions

    Acute avulsions of unossified ischial apophyses in children may go undetected on radiography. Therapy includes rest and rehabilitation; however, substantial displacement may require surgery. Our purpose is to illustrate the utility of MRI in the detection of these radiographically occult injuries in skeletally immature children. This retrospective study of more than 5 years included children with ischial avulsions who were evaluated with both radiography and MRI within 3 weeks of acute injury. Initially, radiographs were reviewed to identify those children with unossified ischial apophyses. Subsequently, their MRI examinations were assessed for physeal disruption, bone/soft tissue edema, periosteal/perichondrial elevation and disruption. Initial and follow-up radiographs (if available) were reviewed. Patient age, symptoms and offending activity were determined from clinical records. Five children met inclusion criteria. All initial radiographs were normal. MRI showed: edema (n = 5), periosteal elevation (n = 4), periosteal/perichondrial disruption (n = 4), >5.5 mm displacement (n = 0). Follow-up radiographs in two children (2 and 2.5 months from MRI) showed osseous ischial irregularity. The apophyses remained unossified. Acute unossified ischial apophyseal avulsions in children may be radiographically undetected. In the setting of correlative clinical symptoms, MRI can be used to identify these injuries and to help direct appropriate therapy. (orig.)

  2. New Occultation Systems and the 2005 July 11 Charon Occultation

    Young, L. A.; French, R. G.; Gregory, B.; Olkin, C. B.; Ruhland, C.; Shoemaker, K.; Young, E. F.

    2005-08-01

    Charon's density is an important input to models of its formation and internal structure. Estimates range from 1.59 to 1.83 g/cm3 (Olkin et al. 2003. Icarus 164, 254), with Charon's radius as the main source of uncertainty. Reported values of Charon's radius from mutual events range from 593±13 (Buie et al. 1992, Icarus 97, 211) to 621±21 km (Young & Binzel 1994, Icarus 108), while an occultation observed from a single site gives a lower limit on the radius of 601.5 km (Walker 1980 MNRAS 192, 47; Elliot & Young 1991, Icarus 89, 244). On 2005 July 11 UT (following this abstract submission date), Charon is predicted to occult the star C313.2. If successful, this event will be the first Charon occultation observed since 1980, and the first giving multiple chords across Charon's disk. This event is expected to measure Charon's radius to 1 km. Our team is observing from three telescopes in Chile, the 4.0-m Blanco and the 0.9-m telescopes at Cerro Tololo and the 4.2-m SOAR telescope at Cerro Pachon. At SOAR, we will be using the camera from our new PHOT systems (Portable High-speed Occultation Telescopes). The PHOT camera is a Princeton Instrument MicroMAX:512BFT from Roper Scientific, a 512×512 frame-transfer CCD with a readnoise of only 3 electrons at the 100 kHz digitization rate. The camera's exposures are triggered by a custom built, compact, stand-alone GPS-based pulse-train generator. A PHOT camera and pulse-train generator were used to observe the occultation of 2MASS 1275723153 by Pluto on 2005 June 15 UT from Sommers-Bausch Observatory in Boulder Colorado; preliminary analysis shows this was at best a grazing occultation from this site and a successful engineering run for the July 11 Charon occultation. The work was supported, in part, by NSF AST-0321338 (EFY) and NASA NNG-05GF05G (LAY).

  3. Zonal flow dynamics and anomalous transport

    Nonlinear equations for the slow space-time evolution of the radial drift wave-ion-temperature gradient (DW-ITG) envelope and zonal flow (ZF) amplitude have been derived within a coherent four-wave drift wave-zonal flow model. In the local limit this model demonstrates spontaneous generation of zonal flow and nonlinear drift wave-zonal flow dynamics in toroidal plasmas. The model allows slow temporal and spatial variations of the DW-ITG radial envelope, incorporating the effects of equilibrium variations, i.e., turbulence spreading and size dependence of the saturated wave intensities and transport coefficients. The competition between linear drive/damping and drift wave spreading due to linear and nonlinear group velocities and nonlinear energy transfer between DW and ZF determines the saturation levels of the fluctuating fields. The turbulence intensity level exhibits a transition from Bohm scaling at small system size (Lp/ρi) to gyro-Bohm for large system size. This system exhibits chaotic behavior and intermittency, depending on system size and proximity to marginal stability

  4. 21 CFR 864.6550 - Occult blood test.

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Occult blood test. 864.6550 Section 864.6550 Food... DEVICES HEMATOLOGY AND PATHOLOGY DEVICES Manual Hematology Devices § 864.6550 Occult blood test. (a) Identification. An occult blood test is a device used to detect occult blood in urine or feces. (Occult blood...

  5. Coherent structure of zonal flow and onset of turbulent transport

    Excitation of the turbulence in the range of drift wave frequency and zonal flow in magnetized plasmas is analyzed. Nonlinear stabilization effect on zonal flow drive is introduced, and the steady state solution is obtained. The condition for the onset of turbulent transport is obtained and partition ratio of fluctuation energy into turbulence and zonal flows is derived. The turbulent transport coefficient, which includes the effect of zonal flow, is also obtained. Analytic result and direct numerical simulation show a good agreement. (author)

  6. Radioimmune localization of occult carcinoma

    Patients with a rising serum carcinoembryonic antigen level and no clinical or roentgenographic evidence of recurrent or metastatic cancer present a treatment dilemma. Eleven such patients, 10 with a previously treated colorectal carcinoma and 1 with a previously treated breast carcinoma, received an injection of the anticarcinoembryonic antigen monoclonal antibody ZCE-025 labeled with the radioisotope indium 111. Nuclear scintigraphy was performed on days 3 and 5 through 7 to detect potential sites of tumor recurrence. The monoclonal antibody scan accurately predicted the presence or absence of occult malignancy in 7 (64%) patients. Second-look laparotomy confirmed the monoclonal antibody scan results in the patients with colorectal cancer, and magnetic resonance imaging confirmed metastatic breast cancer. This study demonstrates that In-ZCE-025 can localize occult carcinoma and may assist the surgeon in facilitating the operative exploration. In-ZCE-025 assisted in the initiation of adjuvant therapy for the patient with breast cancer

  7. Occult Communications: On Instrumentation, Esotericism, and Epistemology

    Bernard Dionysius Geoghegan

    2015-01-01

    Viewed from the perspective of the occult, formerly straight and narrow conduits of reason may even begin to resemble irregular relays composed of irregular twists and turns. This essay offers a brief overview of key literature on spiritualism and the occult, some larger reflections on the place of the occult within studies of science and communications, and brief summaries of the essays contained in this volume.

  8. Laboratory Exploration of Multiple Zonal Jet Regimes

    Smith, C. A.; Speer, K. G.; Griffiths, R. W.

    2012-12-01

    The differentially heated, rotating annulus has classically been used to study wave interactions within a single, baroclinic jet. At high rotation rates, the baroclinic instability of the flow leads to a transition to a turbulent, eddy-dominated regime. In the presence of a topographic beta effect, the flow has been observed to produce multiple, meandering zonal jets that are qualitatively similar to those found in planetary atmospheres and in the Antarctic Circumpolar Current (ACC). Our study builds on previous annulus experiments [1] by making observations further within this new regime. We observe with PIV and other techniques how the structure of the flow responds to changes in various parameters such as tank geometry, gradient in the Coriolis parameter, rotation rate, and differential thermal forcing. By not employing the more typical direct forcing of small scales, but by applying a large scale forcing over the annulus gap width, this study allows the varying effects of eddy scale selection, enstrophy cascade, etc. to naturally generate flow that more closely resembles planetary atmospheres and the ACC. We seek nondimensional parameters that significantly control zonation in a real fluid. These observations will provide a metric for the comparison of various theoretical models for multiple zonal jet formation. Other properties of the jets, such as their migration, meandering, bifurcation, and merging, can also be observed in an idealized situation and compared to numerical simulations. Ultimately, this will aid the testing and development of sub-grid-scale parameterizations for the multiple zonal jet regime that remain robust in the face of multiple forcing parameters. [1] Wordsworth, R. D., Read, P. L., & Yamazaki, Y. H. (2008). Turbulence, waves, and jets in a differentially heated rotating annulus experiment Physics of Fluids, 20(12), 126602.Streak photograph of suspended particles visualizing the flow representative of multiple zonal jets

  9. Pathogenesis of occult chronic hepatitis B virus infection

    Rocio Aller de la Fuente; María L Gutiérrez; Javier Garcia-Samaniego; Conrado Fernández-Rodriguez; Jose Luis Lledó; Gregorio Castellano

    2011-01-01

    Occult hepatitis B infection (OBI) is characterized by hepatitis B virus (HBV) DNA in serum in the absence of hepatitis B surface antigen (HBsAg) presenting HBsAg-negative and anti-HBc positive serological patterns. Occult HBV status is associated in some cases with mutant viruses undetectable by HBsAg assays; but more frequently it is due to a strong suppression of viral replication and gene expression. OBI is an entity with world-wide diffusion. The failure to detect HBsAg, despite the persistence of the viral DNA, is due in most cases to the strong suppression of viral replication and gene expression that characterizes this "occult" HBV infection; although the mechanisms responsible for suppression of HBV are not well understood. The majority of OBI cases are secondary to overt HBV infection and represent a residual low viremia level suppressed by a strong immune response together with histological derangements which occurred during acute or chronic HBV infection. Much evidence suggests that it can favour the progression of liver fibrosis and the development of hepatocellular carcinoma.

  10. Management of occult hepatitis B virus infection: An update for the clinician

    Lledó, José Luis; Fernández, Conrado; Gutiérrez, María Luisa; Ocaña, Sara

    2011-01-01

    Occult hepatitis B virus (HBV) infection (OBI) is defined by the presence of HBV DNA in the liver tissue of individuals who test negative for hepatitis B surface antigen (HBsAg). Patients who have recovered from acute hepatitis B can carry HBV genomes for a long time and show histological patterns of mild necro-inflammation, even fibrosis, years after the resolution of acute hepatitis, without showing any clinical or biochemical evidence of liver disease. At least in conditions of immunocompe...

  11. Occult fracture of the calcaneus - another Toddler's fracture

    Fractures of the calcaneus have been considered rare among children. We feel this may be erroneous since in the last 12 months we have seen 10 such fractures among children, 19 and 41 months of age, who presented with acute limping. The fractures were detected with bone imaging which was performed when initial radiographs were noncontributory. Subsequent radiographs of the calcaneus were positive for fracture in 4 to 10 while follow up radiographs confirmed healing fractures in the two children so evaluated. The sensitivity of bone imaging for the detection of occult fractures in toddlers is emphasized. (orig.)

  12. Monthly Climatology of Thermospheric Zonal and Meridional Winds Obtained from a Kalman Filter Model

    Scherliess, L.; Lomidze, L.

    2015-12-01

    Knowledge of the thermospheric neutral wind and its meridional and zonal components is critical for an improved understanding of the low- and mid-latitude F-region dynamics and morphology. To date, the reliable estimation of the wind and its components remains a challenge because of difficulties in both measurement and modeling. Previous methods that use ionospheric measurements to deduce winds provide their values only in the direction of the magnetic meridian. We will present the monthly climatology of the zonal and meridional components of thermospheric neutral wind at low and mid-latitudes obtained by a Kalman Filter technique. First, the climatology of the magnetic meridional wind is obtained by assimilating monthly maps of F-region ionosphere peak parameters (NmF2 and hmF2), obtained from COSMIC radio occultation data, into the Global Assimilation of Ionospheric Measurements Full Physics (GAIM-FP) model. The model provides the 3-D electron density throughout the ionosphere, together with the magnetic meridional wind. Next, the estimation of the global zonal and meridional wind components is performed using the newly developed Thermospheric Wind Assimilation Model (TWAM). TWAM combines magnetic meridional wind data obtained from GAIM-FP with a physics-based 3-D thermospheric neutral wind model using an implicit Kalman Filter technique. The ionospheric drag and ion diffusion velocities, needed for the wind calculation, are also taken from the GAIM-FP model. We present the monthly climatology of our wind estimation and compare individual horizontal wind components to their corresponding empirical model values and to measurements made by interferometers.

  13. Saturn Ring Mass and Zonal Gravitational Harmonics Estimate at the End of the Cassini "Grand Finale"

    Brozovic, M.; Jacobson, R. A.; Roth, D. C.

    2015-12-01

    "Solstice" mission is the 7-year extension of the Cassini-Huygens spacecraft exploration of the Saturn system that will culminate with the "Grand Finale". Beginning in mid-2017, the spacecraft is scheduled to execute 22 orbits that have their periapses between the innermost D-ring and the upper layers of Saturn's atmosphere. These orbits will be perturbed by the gravitational field of Saturn as well as by the rings. We present an analysis of simulated "Grand Finale" radiometric data, and we investigate their sensitivity to the ring mass and higher zonal gravitational harmonics of the planet. We model the data quantity with respect to the available coverage of the tracking stations on Earth, and we account for the times when the spacecraft is occulted either by Saturn or the rings. We also use different data weights to simulate changes in the data quality. The dynamical model of the spacecraft motion includes both gravitational and non-gravitational forces, such as the daily momentum management due to Reaction Wheel Assembly and radioisotope thermo-electric generator accelerations. We solve the equations of motion and use a weighted-least squares fit to obtain spacecraft's state vector, mass(es) of the ring or the individual rings, zonal harmonics, and non-gravitational accelerations. We also investigate some a-priori values of the A- and B-ring masses from Tiscareno et al. (2007) and Hedman et al. (2015) analyses. The preliminary results suggest that the "Grand Finale" orbits should remain sensitive to the ring mass even for GMring<2 km3/s2 and that they will also provide high accuracy estimates of the zonal harmonics J8, J10, and J12.

  14. Convective towers detection using GPS radio occultations

    Biondi, Riccardo; Neubert, Torsten; Syndergaard, S.;

    an important role since they lead to deep convective activity. With this work we want to investigate if severe storms leave a significant signature in radio occultation profiles in the tropical tropopause layer. The GPS radio occultation (RO) technique is useful for studying severe weather phenomena because...

  15. The Transneptunian Automated Occultation Survey (TAOS II)

    Lehner, Matthew J.; Wang, S.; Alcock, C. A.; Cook, K. H.; Furesz, G.; Geary, J. C.; Hiriart, D.; Ho, P. T.; Norton, T.; Reyes-Ruiz, M.; Szentgyorgyi, A.; Yen, W.; Zhang, Z.

    2012-10-01

    The Transneptunian Automated Occultation Survey (TAOS II) will aim to detect occultations of stars by small ( 1 km diameter) objects in the Solar System and beyond. Such events are very rare (field of view and a high speed camera comprising CMOS imagers, the survey will monitor 10,000 stars simultaneously with all three telescopes at a readout cadence of 20 Hz.

  16. Occultation studies of the solar system

    Occultations of stars by planets, satellites, planetary ring systems, asteroids, and comets provide valuable opportunities to probe the Solar System in ways otherwise impossible from the surface of the earth. For example, one can precisely measure the size and shape of objects which are much too small to be resolved directly, accurately map the structure and transparency of ring systems, and detect the faintest trace of an atmosphere. In this investigation, researchers identify upcoming occultations through wide-ranging computer searches, provide accurate predictions for the more important events, and observe selected occultations with our specially designed portable photometric equipment. During the past year, researchers produced accurate predictions for an occultation of AG+40 degrees 0783 by 324 Bamberga on 8 December 1987 and coordinated efforts to observe this event. The occultation was successfully observed at 13 sites including two manned by Lowell Observatory astronomers

  17. Occultations for probing atmosphere and climate

    Foelsche, Ulrich; Steiner, Andrea

    2004-01-01

    Use of occultation methodology for observing the Earth's atmosphere and climate has become so broad as to comprise solar, lunar, stellar, navigation and satellite­ crosslink occultation methods. The atmospheric parameters obtained extend from the fundamental variables temperature, density, pressure, water vapor, and ozone via a multitude of trace gas species to particulate species such as aerosols and cloud liquid water. Ionospheric electron density is sensed as well. The methods all share the key properties of self-calibration, high accuracy and vertical resolution, global coverage, and (if using radio signals) all-weather capability. Occultation data are thus of high value in a wide range of fields including climate monitoring and research, atmospheric physics and chemistry, operational meteorology, and other fields such as space weather and planetary science. This wide area of variants and uses of the occultation method has led to a diversi­ fication of the occultation-related scientific community into a...

  18. Predictability of Zonal Means During Boreal Summer

    Schubert, Siegfried; Suarez, Max J.; Pegion, Philip J.; Kistler, Michael A.; Kumar, Arun; Einaudi, Franco (Technical Monitor)

    2001-01-01

    This study examines the predictability of seasonal means during boreal summer. The results are based on ensembles of June-July-August (JJA) simulations (started in mid May) carried out with the NASA Seasonal-to-Interannual Prediction Project (NSIPP-1) atmospheric general circulation model (AGCM) forced with observed sea surface temperatures (SSTS) and sea ice for the years 1980-1999. We find that the predictability of the JJA extra-tropical height field is primarily in the zonal mean component of the response to the SST anomalies. This contrasts with the cold season (January-February-March) when the predictability of seasonal means in the boreal extratropics is primarily in the wave component of the El Nino/Southern Oscillation (ENSO) response. Two patterns dominate the interannual variability of the ensemble mean JJA zonal mean height field. One has maximum variance in the tropical/subtropical upper troposphere, while the other has substantial variance in middle latitudes of both hemispheres. Both are symmetric with respect to the equator. A regression analysis suggests that the tropical/subtropical pattern is associated with SST anomalies in the far eastern tropical Pacific and the Indian Ocean, while the middle latitude pattern is forced by SST anomalies in the tropical Pacific just east of the dateline. The two leading zonal height patterns are reproduced in model runs forced with the two leading JJA SST patterns of variability. A comparison with observations shows a signature of the middle latitude pattern that is consistent with the occurrence of dry and wet summers over the United States. We hypothesize that both patterns, while imposing only weak constraints on extratropical warm season continental-scale climates, may play a role in the predilection for drought or pluvial conditions.

  19. Numerical Simulation on Zonal Disintegration in Deep Surrounding Rock Mass

    Xuguang Chen; Yuan Wang; Yu Mei; Xin Zhang

    2014-01-01

    Zonal disintegration have been discovered in many underground tunnels with the increasing of embedded depth. The formation mechanism of such phenomenon is difficult to explain under the framework of traditional rock mechanics, and the fractured shape and forming conditions are unclear. The numerical simulation was carried out to research the generating condition and forming process of zonal disintegration. Via comparing the results with the geomechanical model test, the zonal disintegration p...

  20. The value of low field MR imaging with STIR sequence in diagnosing bone contusions and occult fractures of the knee joint

    Objective: To evaluate the low field MR imaging with STIR sequence in diagnosing bone contusions and occult fractures of the knee joint. Methods: 35 patients with acute trauma of the knee joint were examined using X- ray and MRI, 3 cases also underwent CT examinations. MR sequences included FSE T1WI,T2WI, STIR and GRE. The MRI findings of the bone contusions and occult fractures were analyzed. Results: All 35 cases had normal radiographic results, 33 bone contusions were revealed on MRI FSE sequences, 49 bone contusions and 13 occult fractures on MRI STIR sequences. The location, extent and shape of bone contusions and occult fractures were delineated accurately on MRI STIR sequence. Conclusion: MRI have fairly high advantage in diagnosing bone contusions and occult fractures and STIR would be the best effective sequence. (authors)

  1. Outcome of Concurrent Occult Hemothorax and Pneumothorax in Trauma Patients Who Required Assisted Ventilation

    Ismail Mahmood

    2015-01-01

    Full Text Available Background. The management and outcomes of occult hemopneumothorax in blunt trauma patients who required mechanical ventilation are not well studied. We aimed to study patients with occult hemopneumothorax on mechanical ventilation who could be carefully managed without tube thoracostomy. Methods. Chest trauma patients with occult hemopneumothorax who were on mechanical ventilation were prospectively evaluated. The presence of hemopneumothorax was confirmed by CT scanning. Hospital length of stay, complications, and outcome were recorded. Results. A total of 56 chest trauma patients with occult hemopneumothorax who were on ventilatory support were included with a mean age of 36 ± 13 years. Hemopneumothorax was managed conservatively in 72% cases and 28% underwent tube thoracostomy as indicated. 29% of patients developed pneumonia, 16% had Acute Respiratory Distress Syndrome (ARDS, and 7% died. Thickness of hemothorax, duration of mechanical ventilation, and development of ARDS were significantly associated with tube thoracostomy in comparison to no-chest tube group. Conclusions. The majority of occult hemopneumothorax can be carefully managed without tube thoracostomy in patients who required positive pressure ventilation. Tube thoracotomy could be restricted to those who had evidence of increase in the size of the hemothorax or pneumothorax on follow-up chest radiographs or developed respiratory compromise.

  2. Persistent occult hepatitis B virus infection: Experimental findings and clinical implications

    2007-01-01

    Hepatitis B virus (HBV) is a highly pathogenic virus that causes chronic liver diseases in millions of people globally. In addition to a symptomatic, serologically evident infection, occult persistent HBV carriage has been identified since nucleic acid amplification assays of enhanced sensitivity became introduced for detection of hepadnaviral genomes and their replicative intermediates. Current evidence indicates that occult HBV infection is a common and long-term consequence of resolution of acute hepatitis B. This form of residual infection is termed as secondary occult infection (SOI).The data from the woodchuck model of HBV infection indicate that exposure to small amounts of hepadnavirus can also cause primary occult infection (POI) where virus genome, but no serological makers of exposure to virus, are detectable, and the liver may not be involved.However, virus replicates at low levels in the lymphatic system in both these forms. We briefly summarize the current understanding of the nature and characteristics of occult hepadnaviral persistence as well as of its documented and expected pathological consequences.

  3. Zonal flow formation in the presence of ambient mean shear

    Hsu, Pei-Chun; Diamond, P. H. [Center for Astrophysics and Space Sciences and Department of Physics, University of California San Diego, La Jolla, California 92093-0424 (United States)

    2015-02-15

    The effect of mean shear flows on zonal flow formation is considered in the contexts of plasma drift wave turbulence and quasi-geostrophic turbulence models. The generation of zonal flows by modulational instability in the presence of large-scale mean shear flows is studied using the method of characteristics as applied to the wave kinetic equation. It is shown that mean shear flows reduce the modulational instability growth rate by shortening the coherency time of the wave spectrum with the zonal shear. The scalings of zonal flow growth rate and turbulent vorticity flux with mean shear are determined in the strong shear limit.

  4. Currents, Geostrophic, Aviso, 0.25 degrees, Global, Zonal

    National Oceanic and Atmospheric Administration, Department of Commerce — Aviso Zonal Geostrophic Current is inferred from Sea Surface Height Deviation, climatological dynamic height, and basic fluid mechanics.

  5. Sociology of religion and the occult revival

    Lennart Ejerfeldt

    1975-01-01

    Full Text Available The "new" that makes the cults of the occult revival to "new religions" of the Western world, is their recently increased social significance. Historically most of modern occultism is anything but new. From the research and theorizing about the occult revival we have picked up some main themes. The first is the social diffusion of the new occultism. In this field, we find some studies of superstition, especially astrology. These illuminate the differences in social connotation between the consumers of superstition and the followers of institutional religion. Secondly the study of the occult revival has made valuable contributions to the conceptualizing of "cult" and the cultic phenomenon. Thirdly, we will look upon the connection between the occult revival and the counter-culture. The problem of the rise of cults as a symptom of socio-cultural change will be briefly discussed with reference to Bell's thesis of "the disjuntion of culture and social structure". Lastly, we proffer some reflections on the occult revival and the new spiritual trends in the churches, which so sharply contrast with the theology and churchmanship of the sixties.

  6. The occultation of Arcturus in the Vatican

    Sigismondi, Costantino

    2013-01-01

    The dome of Saint Peter's Basilica plays the role of the Moon during a stellar occultation and Arcturus is the target star. This occultation-like phenomenon is useful for introducing to occultation astronomy a class of student up to university level. It can be organized very easily at the convenience of the audience. Techical and didactical aspects are discussed; the video is available at http://www.youtube.com/watch?v=hIfsj7t-u-c and has been realized with an ordinary camcorder.

  7. Phase-Occultation Nulling Coronagraphy

    Lyon, Richard G; Clampin, Mark; Petrone, Peter

    2015-01-01

    The search for life via characterization of earth-like planets in the habitable zone is one of the key scientific objectives in Astronomy. We describe a new phase-occulting (PO) interferometric nulling coronagraphy (NC) approach. The PO-NC approach employs beamwalk and freeform optical surfaces internal to the interferometer cavity to introduce a radially dependent plate scale difference between each interferometer arm (optical path) that nulls the central star at high contrast while transmitting the off-axis field. The design is readily implemented on segmented-mirror telescope architectures, utilizing a single nulling interferometer to achieve high throughput, a small inner working angle (IWA), sixth-order or higher starlight suppression, and full off-axis discovery space, a combination of features that other coronagraph designs generally must trade. Unlike previous NC approaches, the PO-NC approach does not require pupil shearing; this increases throughput and renders it less sensitive to on-axis common-mo...

  8. Zonal polynomials and hypergeometric functions of quaternion matrix argument

    Li, Fei; Xue, Yifeng

    2009-01-01

    We define zonal polynomials of quaternion matrix argument and deduce some important formulae of zonal polynomials and hypergeometric functions of quaternion matrix argument. As an application, we give the distributions of the largest and smallest eigenvalues of a quaternion central Wishart matrix $W\\sim\\mathbb{Q}W(n,\\Sigma)$, respectively.

  9. McDonald's and the Occult.

    Singer, Barry

    1979-01-01

    Discusses "occult" and "paranormal" literature which is often mistaken for nonfiction. Suggests that most publishers are unwilling to publish scientific perspectives on the paranormal because such writings would be unmarketable. Journal availability: see SO 507 190. (KC)

  10. PICO: Portable Instrument for Capturing Occultations

    Lockhart, Matthew; Person, Michael J.; Elliot, J. L.; Souza, Steven P.

    2010-10-01

    We describe a portable imaging photometer for the observation of stellar occultation events by Kuiper Belt objects (KBOs) and other small bodies. The system is referred to as the Portable Instrument for Capturing Occultations (PICO). It is designed to be transportable to remote observing sites by a single observer. A GPS timing system is used to trigger exposures of a Finger Lakes Instrumentation ML261E-25 camera to facilitate the combination of observational results from multiple sites. The system weighs a total of 11 kg when packed into its single rigid 55.1 × 35.8 × 22.6 cm container, meeting current airline size and weight limits for carry-on baggage. Twelve such systems have been constructed. Nine systems were deployed for observation of a stellar occultation by Kuiper Belt object 55636 in 2009 October. During the same month, one system was used to record a stellar occultation by minor planet 762 Pulcova.

  11. Zonal Flows and Turbulence in Fluids and Plasmas

    Parker, Jeffrey B

    2015-01-01

    In geophysical and plasma contexts, zonal flows are well known to arise out of turbulence. We elucidate the transition from statistically homogeneous turbulence without zonal flows to statistically inhomogeneous turbulence with steady zonal flows. Starting from the Hasegawa--Mima equation, we employ both the quasilinear approximation and a statistical average, which retains a great deal of the qualitative behavior of the full system. Within the resulting framework known as CE2, we extend recent understanding of the symmetry-breaking `zonostrophic instability'. Zonostrophic instability can be understood in a very general way as the instability of some turbulent background spectrum to a zonally symmetric coherent mode. As a special case, the background spectrum can consist of only a single mode. We find that in this case the dispersion relation of zonostrophic instability from the CE2 formalism reduces exactly to that of the 4-mode truncation of generalized modulational instability. We then show that zonal flow...

  12. Occultation Searches for Kuiper Belt Objects

    Cooray, A R; Cooray, Asantha; Farmer, Alison J.

    2003-01-01

    The occultation of background stellar sources by foreground Kuiper Belt Objects (KBOs) can be used to survey physical properties of the KBO population. We discuss statistics related to a KBO occultation survey, such as the event duration distribution, and suggest that occultation searches can be effectively used to probe the KBO size distribution below 10 km. In particular, we suggest that occultation surveys may be best suited to search for a turnover radius in the KBO size distribution due to collisions between small-size objects. For occultation surveys that monitor stellar sources near the ecliptic over a few square degrees, with time sampling intervals of order 0.1 sec and sensitivity to flux variations of a few percent or more, a turnover radius between 0.1 and 1.0 km can be probed. While occultation surveys will probe the low-radius limit and imaging surveys will detect KBOs of size 100 km or more, statistics of objects with sizes in the intermediate range of around 1 km to 100 km will likely remain un...

  13. Radio occultation measurements of the lunar ionosphere.

    Pluchino, S.; Schillirò, F.; Salerno, E.; Pupillo, G.; Maccaferri, G.; Cassaro, P.

    Radio occultation measurements by using interplanetary probes is a well known technique to obtain information on planetary atmospheres. To further understand the morphology of the lunar ionosphere we performed radio occultation experiments by using the radio sounding technique. This method mainly consists in the analisys of the effects produced on the radio wave transmitted from the spacecraft to the Earth when it crosses the atmosphere. The wave amplitude and phase undergo modifications that are correlated to the physical parameters - i.e. electron density - of the crossed medium. The first data set was obtained during the lunar occultations of the European probe SMART-1 shortly before impacting the lunar soil on September 3rd, 2006. During this experiment several radio occultation measurements of the signal transmitted by the spacecraft were performed in S and X band by using the 32 meters radiotelescopes (at Medicina and Noto) of the Istituto di Radioastronomia - Istituto Nazionale di Astrofisica. Further experiments were performed during lunar occultations of Saturn and Venus. On May 22nd and June 18th 2007 the Cassini spacecraft, orbiting Saturn, and the Venus Express spacecraft, orbiting Venus, respectively were occulted by the Moon. The variation of the Total Electron Content (TEC) measured by our instruments (˜ 1013 el/m2) on this occasion is in agreement with values of the electron number density acquired by in situ measuments of the US Apollo missions and the USSR Luna 19 and 22 probes.

  14. Progress on an external occulter testbed at flight Fresnel numbers

    Kim, Yunjong; Sirbu, Dan; Galvin, Michael; Kasdin, N. Jeremy; Vanderbei, Robert J.

    2016-01-01

    An external occulter is a spacecraft flown along the line-of-sight of a space telescope to suppress starlight and enable high-contrast direct imaging of exoplanets. Laboratory verification of occulter designs is necessary to validate the optical models used to design and predict occulter performance. At Princeton, we have designed and built a testbed that allows verification of scaled occulter designs whose suppressed shadow is mathematically identical to that of space occulters. The occulter testbed uses 78 m optical propagation distance to realize the flight Fresnel numbers. We will use an etched silicon mask as the occulter. The occulter is illuminated by a diverging laser beam to reduce the aberrations from the optics before the occulter. Here, we present first light result of a sample design operating at a flight Fresnel number and the mechanical design of the testbed. We compare the experimental results with simulations that predict the ultimate contrast performance.

  15. Method of Modeling and Simulation of Shaped External Occulters

    Lyon, Richard G. (Inventor); Clampin, Mark (Inventor); Petrone, Peter, III (Inventor)

    2016-01-01

    The present invention relates to modeling an external occulter including: providing at least one processor executing program code to implement a simulation system, the program code including: providing an external occulter having a plurality of petals, the occulter being coupled to a telescope; and propagating light from the occulter to a telescope aperture of the telescope by scalar Fresnel propagation, by: obtaining an incident field strength at a predetermined wavelength at an occulter surface; obtaining a field propagation from the occulter to the telescope aperture using a Fresnel integral; modeling a celestial object at differing field angles by shifting a location of a shadow cast by the occulter on the telescope aperture; calculating an intensity of the occulter shadow on the telescope aperture; and applying a telescope aperture mask to a field of the occulter shadow, and propagating the light to a focal plane of the telescope via FFT techniques.

  16. Ring Orbits from Multiple Occultation Observations

    French, Richard G.; McGhee, C. A.; Marouf, E. A.; Rappaport, N.

    2006-09-01

    Planetary rings provide a remarkable laboratory for the investigation of a wide range of dynamical effects, including resonance-driven density and bending waves, satellite wakes, shepherding of narrow ringlets, and non-circular edges of gaps. Careful quantitative examination of these features requires a very accurate absolute radius scale and planetary pole direction, achievable by combining multiple stellar and radio occultation observations. Uncertainty in the location of the spacecraft (at the km level) introduces a fundamental uncertainty into the geometric solution for the ring radius scale, and in the end one must solve for corrections to the spacecraft trajectory as part of the overall determination of the ring orbital model. Using JPL's NAIF toolkit, we have developed accurate algorithms for computing the event time of a ring occultation during an Earth-based or spacecraft occultation, including the effects of spacecraft trajectory errors mapped in two orthogonal directions transverse to the line of sight, based on osculating orbital elements for the instantaneous spacecraft path. These are the fundamental building blocks for a global solution for the pole direction and orbits of the rings of Saturn and Uranus. For Uranus, our new orbit solution includes the full set of digitally recorded occultation data from 1977-2002, yielding a radius scale accurate at the 100 meter level. For Saturn, we explore the potential for highly accurate ring orbit determination as occultation observations from dozens of stellar and radio occultations become publicly available over the course of the ongoing Cassini orbital tour. Saturn's pole precession is also detectable from ring occultation data, and we set limits on the accuracy of the precession rate determination and the implications for our understanding of the mass distribution in Saturn's interior. This work was supported in part by the NASA PGG program.

  17. First Stellar Occultation Observation with SOFIA

    Dunham, Edward W.; Bida, T.; Bosh, A.; Collins, P.; Levine, S.; Person, M.; Pfueller, E.; Roeser, H.; Taylor, B.; Wiedemann, M.; Wolf, J.; Zuluaga, C.

    2012-01-01

    We successfully observed the 2011 June 23 UT stellar occultation by Pluto with the High-speed Imaging Photometer for Occultations (HIPO) instrument from Lowell Observatory and the Fast Diagnostic Camera (FDC) from the Deutches SOFIA Institut (DSI) mounted on the SOFIA telescope. A major prediction astrometry effort focused at MIT combined with the willingness of the SOFIA project to entertain the idea of an in-flight change to the flight plan allowed us to target the center of the occultation shadow. This was accomplished by means of an in-flight prediction update by satellite telephone and a real-time onboard flight plan modification to accommodate the prediction update. We obtained excellent results with both channels of HIPO and the FDC with each light curve showing a small, extended brightening while the star was occulted. We will discuss analysis results as well as SOFIA's considerable potential for future occultation work. We thank the SOFIA program for its willingness to attempt this challenging observation at such an early stage of SOFIA science operations. Lowell's SOFIA work was supported by a grant from USRA, MIT's prediction work was supported by the NASA Planetary Astronomy Program and the National Science Foundation, and the FDC work was supported by the DSI. We thank the US Naval Observatory Flagstaff Station for allowing us to use their facilities to obtain our prediction astrometry observations.

  18. Precise measurement of asteroid sizes and shapes from occultations

    The observational techniques (including photoelectric observations, television recordings, and visual timings) used to measure asteroid dimensions from occultations of stars by asteroids are discussed together with the methods of analysis appropriate to occultation data. Results are presented on the determinations of asteroid diameter, density, and internal structure measures learned from occultations of 36 asteroids. Prospects for continued effective applications of the occultation technique to asteroid studies are discussed. 80 refs

  19. Ipsilateral occult hernias during endoscopic groin hernia repair

    Jain Mayank; Khanna Shashi; Sen Bimalendu; Tantia Om

    2008-01-01

    Endoscopic repair of groin hernias allows the surgeon to have a complete view of the groin and pelvis to diagnose occult hernias both ipsilaterally and contralaterally. These occult hernias can then be treated simultaneously and may reduce the incidence of recurrence and persistent symptoms. The authors present four unusual cases where occult hernias were found ipsilaterally during an endoscopic repair. All these occult hernias were treated along with the clinically diagnosed hernia at the sa...

  20. EQUATORIAL ZONAL JETS AND JUPITER's GRAVITY

    The depth of penetration of Jupiter's zonal winds into the planet's interior is unknown. A possible way to determine the depth is to measure the effects of the winds on the planet's high-order zonal gravitational coefficients, a task to be undertaken by the Juno spacecraft. It is shown here that the equatorial winds alone largely determine these coefficients which are nearly independent of the depth of the non-equatorial winds

  1. Thermospheric zonal mean winds and tides revealed by CHAMP

    Lieberman, R.S.; Akmaev, R. A.; Fuller-Rowell, T. J.; Doornbos, E.

    2013-01-01

    We present direct, global observations of longitudinally averaged CHAMP zonal winds gathered between 2003 and 2007. A diurnal variation dominates the global zonal wind. Westward flows are observed from the early morning through afternoon hours, while eastward flows peak in the evening. A semidiurnal harmonic is also present, with magnitudes that are approximately one third of the diurnal harmonic. The time mean wind indicates westward winds over much of the globe, with weak superrotation (+E,...

  2. Ultrasonography of occult fractures: a pictorial essay

    Occult fractures are a common clinical problem with significant morbidity. All bones may be affected, and routine radiography, the first line of investigation, is often limited in its ability to detect these fractures, despite multiple views. Further investigations in patients with bone or joint-related pain after trauma may include computed tomography (CT), magnetic resonance imaging or radionuclide bone scan. These are relatively expensive imaging modalities. This pictorial essay demonstrates the use of high-resolution ultrasonography (US) in detecting occult fractures, and reviews the implication of its use for first- or second-line investigation in suspected occult fractures. A variety of examples of different fractures will be shown with comparative CT, plain film images or MRI. The added value of power Doppler imaging will also be illustrated. (author)

  3. Scintillation Caustics in Planetary Occultation Light Curves

    Cooray, A R; Cooray, Asantha R.

    2003-01-01

    We revisit the GSC5249-01240 light curve obtained during its occultation by Saturn's North polar region. In addition to refractive scintillations, the power spectrum of intensity fluctuations shows an enhancement of power between refractive and diffractive regimes. We identify this excess power as due to high amplitude spikes in the light curve and suggest that these spikes are due to caustics associated with ray crossing situations. The flux variation in individual spikes follows the expected caustic behavior, including diffraction fringes which we have observed for the first time in a planetary occultation light curve. The presence of caustics in scintillation light curves require an inner scale cut off to the power spectrum of underlying density fluctuations associated with turbulence. Another possibility is the presence of gravity waves in the atmosphere. While occultation light curves previously showed the existence of refractive scintillations, a combination of small projected stellar size and a low rel...

  4. Evaluation for Occult Fractures in Injured Children

    French, Benjamin; Song, Lihai; Feudtner, Chris

    2015-01-01

    OBJECTIVES: To examine variation across US hospitals in evaluation for occult fractures in (1) children physical abuse and (2) infants abuse and to identify factors associated with such variation. METHODS: We performed a retrospective study in children physical abuse and in infants abuse diagnosis, in 51% of the 1574 infants with traumatic brain injury, and in 53% of the 859 infants with femur fractures. Hospitals varied substantially with regard to their rates of evaluation for occult fractures in all 3 groups. Occult fracture evaluations were more likely to be performed at teaching hospitals than at nonteaching hospitals (all P abuse or injuries associated with a high likelihood of abuse highlights opportunities for quality improvement in this vulnerable population. PMID:26169425

  5. Close Double Stars from Occultation Video Recordings

    Waring Dunham, David; George, Anthony; Loader, Brian; Herald, David Russell

    2015-08-01

    Astronomers around the world, both amateur and professional, have been recording lunar and asteroidal occultations of close double stars during the past several years using inexpensive but quite sensitive video cameras that are now available. Several new double stars have been discovered, and the parameters of many close systems have been determined. Besides rather good measurements of the relative magnitudes of the components, the actual separations and position angles can be measured if observations of the same event are made from two or more separate stations. These observations collected by the International Occultation Timing Association (IOTA) are published in the Journal of Double Star Observations. Recently, IOTA has encouraged the observation of occultations of stars in the Kepler 2 program, which is interested in data about close duplicity that affects their analyses for exoplanet transits.

  6. A NOVEL PRESSURIZED ZONAL MODEL USING THE MOMENTUM EQUATION

    Yao Yu

    2014-01-01

    Full Text Available Zonal models combine the simplicity of single and multi-zone models with the comprehensiveness of Computational Fluid Dynamics (CFD models and thus become a better substitute to predict detailed thermal and airflow behaviors in building. Based on a geometric partitioning of a room into a number of subzones, these models give more accurate and detailed results than the single or multi-zone modeling approaches and use less computer resource than CFD models. Nevertheless, most of the zonal models have to face a difficulty involving the limits of the simplification that need to be considered without losing accuracy and comprehensiveness. A new zonal model, called Pressurized zOnal Model using the Momentum Equation (POMME, has been developed, in which a simplified numerical model, representing various heat and mass transfer conservation equations is used. The program solver is similar to those used for CFD programs and is based on the finite-volume numerical techniques, the staggered grid formulation, the Semi-Implicit Method for Pressure-Linked Equations (SIMPLE algorithm and other methods. The validation of this new zonal model has been accomplished by comparing its results with those obtained from the CFD software: PHOENICS. The results demonstrate not only the strength of the zonal model POMME in predicting the indoor airflow and thermal conditions, without the involvement of additional sub-models, but also its ability to provide relatively accurate results for building enclosures.

  7. Collisionless damping of zonal flows in helical systems

    Collisionless time evolution of zonal flows in helical systems are investigated. An analytical expression describing the collisionless response of the zonal-flow potential to the initial potential and a given turbulence source is derived from the gyrokinetic equations combined with the quasineutrality condition. The dispersion relation for the geodesic acoustic mode (GAM) in helical systems is derived from the short-time response kernel for the zonal-flow potential. It is found that helical ripples in the magnetic field strength as well as finite orbit widths of passing ions enhance the GAM damping. The radial drift motions of particles trapped in helical ripples cause the residual zonal-flow level in the collisionless long-time limit to be lower for longer radial wave lengths and deeper helical ripples. On the other hand, a high-level zonal-flow response, which is not affected by helical-ripple-trapped particles, can be maintained for a longer time by reducing their radial drift velocity. This implies a possibility that helical configurations optimized for reducing neoclassical ripple transport can simultaneously enhance zonal flows which lower anomalous transport. The validity of our analytical results is verified by gyrokinetic Vlasov simulation. (author)

  8. Characteristics of tropopause parameters as observed with GPS radio occultation

    T. Rieckh

    2014-11-01

    Full Text Available Characteristics of the lapse rate tropopause are analyzed globally for tropopause altitude and temperature using global positioning system (GPS radio occultation (RO data from late 2001 to the end of 2013. RO profiles feature high vertical resolution and excellent quality in the upper troposphere and lower stratosphere, which are key factors for tropopause determination, including multiple ones. RO data provide measurements globally and allow examination of both temporal and spatial tropopause characteristics based entirely on observational measurements. To investigate latitudinal and longitudinal tropopause characteristics, the mean annual cycle, and inter-annual variability, we use tropopauses from individual profiles as well as their statistical measures for zonal bands and 5° × 10° bins. The latitudinal structure of first tropopauses shows the well-known distribution with high (cold tropical tropopauses and low (warm extra-tropical tropopauses. In the transition zones (20 to 40° N/S, individual profiles reveal varying tropopause altitudes from less than 7 km to more than 17 km due to variability in the subtropical tropopause break. In this region, we also find multiple tropopauses throughout the year. Longitudinal variability is strongest at northern hemispheric mid latitudes and in the Asian monsoon region. The mean annual cycle features changes in amplitude and phase, depending on latitude. This is caused by different underlying physical processes (such as the Brewer–Dobson circulation – BDC and atmospheric dynamics (such as the strong polar vortex in the southern hemispheric winter. Inter-annual anomalies of tropopause parameters show signatures of El Niño–Southern Oscillation (ENSO, the quasi–biennial oscillation (QBO, and the varying strength of the polar vortex, including sudden stratospheric warming (SSW events. These results are in good agreement with previous studies and underpin the high utility of the entire RO record

  9. Occult bony lesions associated with anterior cruciate ligament injury

    To examine bony lesions associated with anterior cruciate ligament (ACL) injuries, magnetic resonance (MR) imaging was performed on 55 knees with ACL injuries. With respect to the period between ACL injuries and MR imaging, the knees were divided into acute (within one month), subacute (from one month to one year) and chronic (over one year) groups, containing 19, 16 and 20 knees, respectively. Occult bony lesions not shown in roentgenography were observed more frequently in the acute group (13/19) than in the other two groups (subacute group, 5/16; chronic group, 1/20), located in the lateral compartment of the knee joint. In the acute group, bony lesions had high signal intensity on T2-weighted images and low signal intensity on proton density images. In the subacute and chronic groups, bony lesions were less pronounced and had low signal intensity on T2-weighted images. These findings suggest that bony lesions are frequently associated with and occur simultaneously with ACL injury. (author)

  10. Occult, massive hematomas following antegrade femoral angioplasty

    Small groin hematomas are not uncommon after percuatenous antegrade femoral angioplasty (PAFA) and are usually apparent clinically. The authors describe three patients of 235 who underwent PAFA, in whom occult, massive hemorrhage was detected after the procedure. All patients underwent fluoroscopically guided antegrade punctures, with adequate hemostasis achieved after the procedure. CT revealed extraperitoneal hematomas in two patients. One patient required surgical intervention with ligation of the inferior epigastric artery. The authors postulate that these hematomas arose due to inadvertent injury to a branch of the common femoral artery during the puncture. The radiologist should be aware of the chance occurrence of this occult, potentially life-threatening complication

  11. Altimetry Using GPS-Reflection/Occultation Interferometry

    Cardellach, Estel; DeLaTorre, Manuel; Hajj, George A.; Ao, Chi

    2008-01-01

    A Global Positioning System (GPS)- reflection/occultation interferometry was examined as a means of altimetry of water and ice surfaces in polar regions. In GPS-reflection/occultation interferometry, a GPS receiver aboard a satellite in a low orbit around the Earth is used to determine the temporally varying carrier- phase delay between (1) one component of a signal from a GPS transmitter propagating directly through the atmosphere just as the GPS transmitter falls below the horizon and (2) another component of the same signal, propagating along a slightly different path, reflected at glancing incidence upon the water or ice surface.

  12. The Radio Occultation Processing Package ROPP

    I. D. Culverwell

    2015-01-01

    Full Text Available This paper describes the Radio Occultation Processing Package, ROPP, a product of the EUMETSAT Radio Occultation Meteorology Satellite Application Facility (ROM SAF developed by a large number of scientists over many years. A brief review of the concepts, functionality and structure of ROPP is followed by more detailed descriptions of its key capabilities. Example results from a full chain of processing using some of the ROPP tools are presented. Some current and prospective uses of ROPP are given. Instructions on how to access the code and its supporting documentation are provided.

  13. Clinical Characteristics and Treatment for Patients with Occult Chronic hepatitis B

    2013-01-01

    Objective To observe the clinical manifestations and assess direct antiviral effect for patients with occult hepatitis B in China. Methods The study includes 15 patients with occult hepatitis B and their medical history, family history, ifrst-diagnosis time, conifrmed-diagnosis time, laboratory report, anti-viral therapy and outcomes were analyzed. Results The average age of the patients is 38.67-year old (6 males and 9 females), 2 with acute hepatitis B (2/15, 13.3%), 13 with no hepatitis history (13/15, 86.6%), 8 with family history (8/15, 53.3%), 6 with no family history (6/15, 40%), 1 with unknown family history (1/15, 6.6%). Eight patients were treated with entecavir (0.5 mg/day, taken orally), with effective results and steady conditions;3 patients were treated with lamivudine (0.1 g/day, taken orally), 2 of them were prescribed to take adefovir dipivoxil additionally due to drug-resistance, the other one was treated with lamivudine continuously without drug-resistance;4 cases refused anti-viral therapy. One patient’s condition remained steady, 1 patient died of cirrhosis with portal hypertension and liver failure 5 years after ifrst-diagnosis, 1 patient progressed to hepatocellular carcinoma and accepted surgery operation treatment 5 years after ifrst-diagnosis, the other 1 patient progressed to compensatory cirrhosis 2 years after ifrst-diagnosis and is steady from then, which indicates that occult chronic hepatitis B can progress to cirrhosis and hepatocellular carcinoma without therapy in time. Conclusions The clinical characteristics of 15 cases with occult chronic hepatitis B showed that these patients with short latency, younger age when being-struck, and light damage to liver function. The efifcacy and drug-resistance of nucleos(t)ide-analogue (entecavir, lamivudine, adefovir dipivoxil) in treatment of patients with occult chronic hepatitis B are similar to chronic hepatitis B.

  14. Controversies about occult hepatitis B virus infection

    Ersan Ozaslan; Tugrul Purnak

    2009-01-01

    We read with great interest the paper written by Shi et al, reviewing the molecular characteristics and stages of chronic hepatitis B virus (HBV) infection. We think that some points in the definition of occult HBV infection (OBI) and their conclusion about the management of OBI may need further considerations.

  15. Persistent monoarthritis and occult coeliac disease.

    Borg, A A; Dawes, P T; Swan, C H; Hothersall, T E

    1994-01-01

    Arthritis is a recognized complication of untreated coeliac disease. Symptoms and signs usually respond to the institution of a gluten-free diet. We report a case of occult coeliac disease presenting as a monoarthritis. Severe and progressive erosive damage has occurred in his talo-navicular joint despite a response to the institution of a gluten-free diet.

  16. Occult spondyloarthritis in inflammatory bowel disease.

    Bandinelli, Francesca; Manetti, Mirko; Ibba-Manneschi, Lidia

    2016-02-01

    Spondyloarthritis (SpA) is a frequent extra-intestinal manifestation in patients with inflammatory bowel disease (IBD), although its real diffusion is commonly considered underestimated. Abnormalities in the microbioma and genetic predisposition have been implicated in the link between bowel and joint inflammation. Otherwise, up to date, pathogenetic mechanisms are still largely unknown and the exact influence of the bowel activity on rheumatic manifestations is not clearly explained. Due to evidence-based results of clinical studies, the interest on clinically asymptomatic SpA in IBD patients increased in the last few years. Actually, occult enthesitis and sacroiliitis are discovered in high percentages of IBD patients by different imaging techniques, mainly enthesis ultrasound (US) and sacroiliac joint X-ray examinations. Several diagnostic approaches and biomarkers have been proposed in an attempt to correctly classify and diagnose clinically occult joint manifestations and to define clusters of risk for patient screening, although definitive results are still lacking. The correct recognition of occult SpA in IBD requires an integrated multidisciplinary approach in order to identify common diagnostic and therapeutic strategies. The use of inexpensive and rapid imaging techniques, such as US and X-ray, should be routinely included in daily clinical practice and trials to correctly evaluate occult SpA, thus preventing future disability and worsening of quality of life in IBD patients. PMID:26354428

  17. Occult hepatitis B infection: an evolutionary scenario

    Lukashov Vladimir V

    2008-12-01

    Full Text Available Abstract Background Occult or latent hepatitis B virus (HBV infection is defined as infection with detectable HBV DNA and undetectable surface antigen (HBsAg in patients' blood. The cause of an overt HBV infection becoming an occult one is unknown. To gain insight into the mechanism of the development of occult infection, we compared the full-length HBV genome from a blood donor carrying an occult infection (d4 with global genotype D genomes. Results The phylogenetic analysis of polymerase, core and X protein sequences did not distinguish d4 from other genotype D strains. Yet, d4 surface protein formed the evolutionary outgroup relative to all other genotype D strains. Its evolutionary branch was the only one where accumulation of substitutions suggests positive selection (dN/dS = 1.3787. Many of these substitutiions accumulated specifically in regions encoding the core/surface protein interface, as revealed in a 3D-modeled protein complex. We identified a novel RNA splicing event (deleting nucleotides 2986-202 that abolishes surface protein gene expression without affecting polymerase, core and X-protein related functions. Genotype D strains differ in their ability to perform this 2986-202 splicing. Strains prone to 2986-202 splicing constitute a separate clade in a phylogenetic tree of genotype D HBVs. A single substitution (G173T that is associated with clade membership alters the local RNA secondary structure and is proposed to affect splicing efficiency at the 202 acceptor site. Conclusion We propose an evolutionary scenario for occult HBV infection, in which 2986-202 splicing generates intracellular virus particles devoid of surface protein, which subsequently accumulates mutations due to relaxation of coding constraints. Such viruses are deficient of autonomous propagation and cannot leave the host cell until it is lysed.

  18. Magnetic Field Generation and Zonal Flows in the Gas Giants

    Duarte, L.; Wicht, J.; Gastine, T.

    2013-12-01

    The surface dynamics of Jupiter and Saturn is dominated by a banded system of fierce zonal winds. The depth of these winds remains unclear but they are thought to be confined to the very outer envelopes where hydrogen remains molecular and the electrical conductivity is negligible. The dynamo responsible for the dipole dominated magnetic fields of both Gas Giants, on the other hand, likely operates in the deeper interior where hydrogen assumes a metallic state. We present numerical simulations that attempt to model both the zonal winds and the interior dynamo action in an integrated approach. Using the anelastic version of the MHD code MagIC, we explore the effects of density stratification and radial electrical conductivity variations. The electrical conductivity is assumed to remain constant in the thicker inner metallic region and decays exponentially towards the outer boundary throughout the molecular envelope. Our results show that the combination of stronger density stratification (Δρ≈55) and a weaker conducting outer layer is essential for reconciling dipole dominated dynamo action and a fierce equatorial zonal jet. Previous simulations with homogeneous electrical conductivity show that both are mutually exclusive, with solutions either having strong zonal winds and multipolar magnetic fields or weak zonal winds and dipole dominated magnetic fields. The particular setup explored here allows the equatorial jet to remain confined to the weaker conducting region where is does not interfere with the deeper seated dynamo action. The equatorial jet can afford to remain geostrophic and reaches throughout the whole shell. This is not an option for the additional mid to higher latitude jets, however. In dipole dominated dynamo solutions, appropriate for the Gas Giants, zonal flows remain very faint in the deeper dynamo region but increase in amplitude in the weakly conducting outer layer in some of our simulations. This suggests that the mid to high latitude jets

  19. A zonally symmetric model for volcanic influence upon atmospheric circulation

    Schatten, K. H.; Mayr, H. G.; Harris, I.; Taylor, H. A., Jr.

    1984-01-01

    The effects of volcanic activity upon zonal wind flow in a model atmosphere are considered. A low latitude volcanic eruption could lower the tropospheric pole to equator temperature difference and thereby affect the atmospheric motions. When the temperature contrast decreases, the zonal wind velocities at high altitudes are reduced. To conserve angular momentum, the velocities in the lower atmosphere near the surface must increase, thus providing a momentum source for ocean currents. It is suggested that this momentum source may have played a role as a trigger for inducing the 1982-83 anomalous El Nino and possibly other climate changes.

  20. Intermittent characteristics in coupling between turbulence and zonal flows

    An extended application of Gabour's wavelet to bicoherence analysis succeeds in resolving the instantaneous structure of three wave couplings between disparate scale electric field fluctuations in the high temperature core in a toroidal plasma device named the compact helical system. The obtained results quantify an intermittent linkage between turbulence and zonal flows-a highlighted issue in the present plasma research. This is the first demonstration that the intermittent nature of the three wave coupling should underlie the turbulence power modulation due to zonal flows

  1. Occult infarct with acute hemorrhagic stroke in juvenile diabetic ketoacidosis.

    Lin, Jainn-Jim; Lin, Kuang-Lin; Wang, Huei-Shyong; Wong, Alex Mun-Ching; Hsia, Shao-Hsuan

    2008-01-01

    Diabetes ketoacidosis (DKA) is one of the common complications of type I insulin-dependent diabetes mellitus. Neurological deterioration during an episode of DKA is usually assumed to be caused by cerebral edema and cerebral vascular accidents. However, hemorrhagic stroke is a very rare complication of juvenile DKA. We describe a girl who had newly diagnosed insulin-dependent diabetes mellitus with juvenile DKA developed intracerebral hemorrhage. PMID:17629647

  2. CASSINI UVIS STELLAR OCCULTATION OBSERVATIONS OF SATURN's RINGS

    The Cassini spacecraft's Ultraviolet Imaging Spectrograph (UVIS) includes a high-speed photometer (HSP) that has observed more than 100 stellar occultations by Saturn's rings. Here, we document a standardized technique applied to the UVIS-HSP ring occultation datasets delivered to the Planetary Data System as higher level data products. These observations provide measurements of ring structure that approaches the scale of the largest common ring particles (∼5 m). The combination of multiple occultations at different viewing geometries enables reconstruction of the three-dimensional structure of the rings. This inversion of the occultation data depends on accurate calibration of the data so that occultations of different stars taken at different times and under different viewing conditions can be combined to retrieve ring structure. We provide examples of the structure of the rings as seen from several occultations at different incidence angles to the rings, illustrating changes in the apparent structure with viewing geometry.

  3. Convective towers detection using GPS radio occultations

    Biondi, Riccardo; Neubert, Torsten; Syndergaard, S.; Nielsen, J.

    2010-01-01

    The tropical deep convection affects the radiation balance of the atmosphere changing the water vapour mixing ratio and the temperature of the upper troposphere and lower stratosphere. To gain a better understanding of deep convective processes, the study of tropical cyclones could play an important role since they lead to deep convective activity. With this work we want to investigate if severe storms leave a significant signature in radio occultation profiles in the tropical tropopause laye...

  4. The JWST/NIRCam Coronagraph Flight Occulters

    Krist, John E.; Balasubramanian, Kunjithapatham; Muller, Richard E.; Shaklan, Stuart B.; Kelly, Douglas M.; Wilson, Daniel W.; Beichman, Charles A.; Serabyn, Eugene; Mao, Yalan; Echternach, Pierre M.; Trauger, John T.; Liewer, Kurt M.

    2010-01-01

    The NIRCam instrument on the James Webb Space Telescope will have a Lyot coronagraph for high contrast imaging of extrasolar planets and circumstellar disks at lambda = 2 - 5 micrometers. Half-tone patterns are used to create graded-transmission image plane masks. These are generated using electron beam lithography and reactive ion etching of a metal layer on an antireflection coated sapphire substrate. We report here on the manufacture and evaluation of the flight occulters.

  5. The JWST/NIRCam coronagraph flight occulters

    Krist, John E.; Balasubramanian, Kunjithapatham; Muller, Richard E.; Shaklan, Stuart B.; Kelly, Douglas M.; Wilson, Daniel W.; Beichman, Charles A.; Serabyn, Eugene; Mao, Yalan; Echternach, Pierre M.; Trauger, John T.; Liewer, Kurt M.

    2010-07-01

    The NIRCam instrument on the James Webb Space Telescope will have a Lyot coronagraph for high contrast imaging of extrasolar planets and circumstellar disks at λ=2 - 5 μm. Half-tone patterns are used to create graded-transmission image plane masks. These are generated using electron beam lithography and reactive ion etching of a metal layer on an antireflection coated sapphire substrate. We report here on the manufacture and evaluation of the flight occulters.

  6. Ultrasound detection of nonpalpable mammographically occult malignancy

    To evaluate the prevalence of occult malignancy with screening breast ultrasound. All ultrasound-guided core needle breast biopsies performed between January 1, 1999, and June 30, 2001, were retrospectively reviewed. Lesions were identified during screening breast ultrasound in high-risk women with no mammographic or palpable abnormality in either breast, a unilateral mammographic or palpable abnormality in the contralateral breast, or a unilateral mammographic or palpable abnormality in a different quadrant of the same breast. All ultrasound-detected lesions were histologically verified. Six hundred and fifty-two women with a mean age of 49 years underwent 698 biopsies during the study period. Three hundred and forty-nine of these lesions were detected at screening breast ultrasound. Out of 349, 11 (3.2%) had a mammographically and clinically occult malignancy. Nine cancers were found in women with no mammographic or palpable abnormality. Two cancers were found in the same breast as the mammographic or palpable abnormality. None were found in the breast contralateral to a palpable or mammographic abnormality. Screening breast ultrasound of high-risk women has a similar detection rate for occult carcinoma as screening mammography, but has a low positive predictive value in cases where biopsy is performed. (author)

  7. OCCULT-ORSER complete conversational user-language translator

    Ramapriyan, H. K.; Young, K.

    1981-01-01

    Translator program (OCCULT) assists non-computer-oriented users in setting up and submitting jobs for complex ORSER system. ORSER is collection of image processing programs for analyzing remotely sensed data. OCCULT is designed for those who would like to use ORSER but cannot justify acquiring and maintaining necessary proficiency in Remote Job Entry Language, Job Control Language, and control-card formats. OCCULT is written in FORTRAN IV and OS Assembler for interactive execution.

  8. What can the Occult do for you? STarlight Attenuation & Reddening Survey of Multiple Occulting Galaxies (STARSMOG)

    Holwerda, B W

    2015-01-01

    Interstellar dust is still the dominant uncertainty in Astronomy, limiting precision in e.g., cosmological distance estimates and models of how light is re-processed within a galaxy. When a foreground galaxy serendipitously overlaps a more distant one, the latter backlights the dusty structures in the nearer foreground galaxy. Such an overlapping or occulting galaxy pair can be used to measure the distribution of dust in the closest galaxy with great accuracy. The STARSMOG program uses HST observation of occulting galaxy pairs to accurately map the distribution of dust in foreground galaxies in fine ($<$100 pc) detail. Furthermore, Integral Field Unit observations of such pairs will map the effective extinction curve in these occulting galaxies, disentangling the role of fine-scale geometry and grain composition on the path of light through a galaxy. The overlapping galaxy technique promises to deliver a clear understanding of the dust in galaxies: the dust geometry, a probability function of the amount of...

  9. Influence of the mean flow on zonal flow generation

    Lashkin, V. M.

    2008-01-01

    Excitation of zonal flow by the modulational instability in the presence of mean shear flow is considered. It is shown that the small amplitude mean flow favours the modulational instability, increasing the growth rate, whereas sufficiently strong mean shear significantly reduces the instability growth rate.

  10. Balanced Data Assimilation For Improving Zonal Equatorial Currents

    Burgers, G.; Balmaseda, M. A.; Vossepoel, F. C.; van Oldenborgh, G. J.; van Leeuwen, P. J.

    Assimilation schemes that are used for seasonal prediction can have a problem in estimating zonal velocities near the equator. This is the case for OI schemes that use density information for updating only the model density field. In some situations, this leads to a detoriation of the zonal velocity field around the equator. The problem is studied first for the assimilation of height observations in a simple linear 1.5 layer shallow-water model of the equatorial Pacific. It is found that equa- torial zonal velocities can be degraded if velocity is not updated in the assimilation procedure, even if the assimilation increments for height are spread over time. Adding updates to the zonal velocity which are related by geostrophic balance to the height updates is shown to be a simple remedy for the shallow-water model. A straightforward generalisation of the balanced data assimilation method has been implemented in the ocean circulation model of the ECMWF seasonal forecasting sys- tem. First tests are encouraging: upper-ocean surface currents are improved, and cou- pled hindcasts are improved if balanced assimilation is used for the ocean analyses.

  11. Can zonally symmetric inertial waves drive an oscillating mean flow?

    Seelig, Torsten; Harlander, Uwe

    2016-04-01

    In the presentation [5] zonal mean flow excitation by inertial waves is studied in analogy to mean flow excitation by gravity waves [3] that plays an important role for the quasi-biennial oscillation in the equatorial atmosphere. In geophysical flows that are stratified and rotating, pure gravity and inertial waves correspond to the two limiting cases: gravity waves neglect rotation, inertial waves neglect stratification. The former are more relevant for fluids like the atmosphere, where stratification is dominant, the latter for the deep oceans or planet cores, where rotation dominates. In the present study a hierarchy of simple analytical and numerical models of zonally symmetric inertial wave-mean flow interactions is considered and the results are compared with data from a laboratory experiment [4]. The main findings can be summarised as follows: (i) when the waves are decoupled from the mean flow they just drive a retrograde (eastward) zonal mean flow, independent of the sign of the meridional phase speed; (ii) when coupling is present and the zonal mean flow is assumed to be steady, the waves can drive vertically alternating jets, but still, in contrast to the gravity wave case, the structure is independent of the sign of the meridional phase speed; (iii) when coupling is present and time-dependent zonal mean flows are considered the waves can drive vertically and temporarily oscillating mean flows. The comparison with laboratory data from a rotating annulus experiment shows a qualitative agreement. It appears that the experiment captures the basic elements of the inertial wave mean flow coupling. The results might be relevant to understand how the Equatorial Deep Jets can be maintained against dissipation [1, 2], a process currently discussed controversially. [1] Greatbatch, R., Brandt, P., Claus, M., Didwischus, S., Fu, Y.: On the width of the equatorial deep jets. J. Phys. Oceanogr. 42, 1729-1740 (2012) [2] Muench, J.E., Kunze, E.: Internal wave

  12. Ipsilateral occult hernias during endoscopic groin hernia repair

    Jain Mayank

    2008-01-01

    Full Text Available Endoscopic repair of groin hernias allows the surgeon to have a complete view of the groin and pelvis to diagnose occult hernias both ipsilaterally and contralaterally. These occult hernias can then be treated simultaneously and may reduce the incidence of recurrence and persistent symptoms. The authors present four unusual cases where occult hernias were found ipsilaterally during an endoscopic repair. All these occult hernias were treated along with the clinically diagnosed hernia at the same surgery with excellent results and no post-operative morbidity.

  13. Survey of the initial management and imaging protocols for occult scaphoid fractures in UK hospitals

    The aim of this research was to survey how occult fractures of the scaphoid bone are both imaged and managed initially. A total of 832 questionnaires were sent via e-mail to active associate members of the British Orthopaedic Association. Included was a series of questions regarding the timing of initial and subsequent orthopaedic review of this group of patients and the use of serial radiographs and second-line imaging techniques. Nearly half of the UK's acute NHS trusts were represented (45%). The response rate was 16% (130 out of 832). Only 16% of respondents were aware of a local imaging protocol for the investigation of suspected fractures of the scaphoid. Ninety-four percent of respondents performed a second radiograph at first fracture clinic review. Fifty-eight percent used magnetic resonance imaging (MRI) as a second-line investigation; with computed tomography scan and radionuclide isotope bone scan being performed by 26% and 16% respondents, respectively. The survey revealed a wide variation in the management of occult fractures of the scaphoid. MRI has been shown to be both sensitive and specific in diagnosing occult carpal bone fractures. There is a need to standardise the management of these injuries to ensure early diagnosis and limit unnecessary wrist immobilisation. (orig.)

  14. The use of MRI and CT in Imaging Occult Hip Fractures

    Obadă B.

    2014-11-01

    Full Text Available Diagnosis of hip fractures is particularly important due to the high dependence on the integrity of this structure for people to function in their daily lives. Left unrecognized, patients face increasing morbidity and mortality as time from the original injury lengthens. A delay of just 2 days in surgical treatment for an acute hip fracture doubles mortality. In addition, an unrecognized non-displaced fracture may displace, requiring surgery of much higher risk. This may be part of the reason that the most frequent lawsuit against Emergency Physicians is for missed orthopedic injury. We reviewed the use of MRI and CT for occult hip fractures (OHF detection at a major urban trauma unit. Our study is a retrospective review. Inclusion criteria: all patients presenting to the Emergency Clinical Hospital of Constanta with a suspected, posttraumatic, occult hip fracture, over a 5 years period were included. All patients had negative initial radiographs and underwent further imaging with either CT or MRI. A total of 185 cases meeting the inclusion criteria were identified. 72 occult hip fractures were detected with both imaging modalities. Although MRI certainly enables greater image detail, in our experience both modalities are able to provide satisfactory fracture characterization. The choice of imaging should be determined by availability and indication. MRI provides superior imaging of soft tissue but is less sensitive for degenerative changes in presence of bone edema.

  15. Survey of the initial management and imaging protocols for occult scaphoid fractures in UK hospitals

    Brookes-Fazakerley, S.D.; Kumar, A.J.S. [Countess of Chester Hospital NHS Foundation Trust, Department of Trauma and Orthopaedics, Chester (United Kingdom); Oakley, J. [Robert Jones and Agnes Hunt Orthopaedic and District Hospital NHS Trust, Oswestry, Shropshire (United Kingdom)

    2009-11-15

    The aim of this research was to survey how occult fractures of the scaphoid bone are both imaged and managed initially. A total of 832 questionnaires were sent via e-mail to active associate members of the British Orthopaedic Association. Included was a series of questions regarding the timing of initial and subsequent orthopaedic review of this group of patients and the use of serial radiographs and second-line imaging techniques. Nearly half of the UK's acute NHS trusts were represented (45%). The response rate was 16% (130 out of 832). Only 16% of respondents were aware of a local imaging protocol for the investigation of suspected fractures of the scaphoid. Ninety-four percent of respondents performed a second radiograph at first fracture clinic review. Fifty-eight percent used magnetic resonance imaging (MRI) as a second-line investigation; with computed tomography scan and radionuclide isotope bone scan being performed by 26% and 16% respondents, respectively. The survey revealed a wide variation in the management of occult fractures of the scaphoid. MRI has been shown to be both sensitive and specific in diagnosing occult carpal bone fractures. There is a need to standardise the management of these injuries to ensure early diagnosis and limit unnecessary wrist immobilisation. (orig.)

  16. Occult fracture of the calcaneus - another toddler's fracture

    Starshak, R.J.; Simons, G.W.; Sty, J.R.

    1984-01-01

    Fractures of the calcaneus have been considered rare among children. We feel this may be erroneous since in the last 12 months we have seen 10 such fractures among children, 19 and 41 months of age, who presented with acute limping. The fractures were detected with bone imaging which was performed when initial radiographs were noncontributory. Subsequent radiographs of the calcaneus were positive for fracture in 4 to 10 while follow up radiographs confirmed healing fractures in the two children so evaluated. The sensitivity of bone imaging for the detection of occult fractures in toddlers is emphasized.

  17. New perspectives in occult hepatitis C virus infection

    Vicente Carre(n)o; Javier Bartolomé; Inmaculada Castillo; Juan Antonio Quiroga

    2012-01-01

    Occult hepatitis C virus (HCV) infection,defined as the presence of HCV RNA in liver and in peripheral blood mononuclear cells (PBMCs) in the absence of detectable viral RNA in serum by standard assays,can be found in anti-HCV positive patients with normal serum levels of liver enzymes and in anti-HCV negative patients with persistently elevated liver enzymes of unknown etiology.Occult HCV infection is distributed worldwide and all HCV genotypes seem to be involved in this infection.Occult hepatitis C has been found not only in anti-HCV positive subjects with normal values of liver enzymes or in chronic hepatitis of unknown origin but also in several groups at risk for HCV infection such as hemodialysis patients or family members of patients with occult HCV.This occult infection has been reported also in healthy populations without evidence of liver disease.Occult HCV infection seems to be less aggressive than chronic hepatitis C although patients affected by occult HCV may develop liver cirrhosis and even hepatocellular carcinoma.Thus,anti-HCV negative patients with occult HCV may benefit from antiviral therapy with pegylatedinterferon plus ribavirin.The persistence of very low levels of HCV RNA in serum and in PBMCs,along with the maintenance of specific T-cell responses against HCV-antigens observed during a long-term follow-up of patients with occult hepatitis C,indicate that occult HCV is a persistent infection that is not spontaneously eradicated.This is an updated report on diagnosis,epidemiology and clinical implications of occult HCV with special emphasis on anti-HCV negative cases.

  18. Data analysis of 2005 Regulus occultation and simulation of the 2014 occultation

    Sigismondi, Costantino; Flatrès, Thomas

    2014-01-01

    On March 20, 2014 at 6:06 UT (2:06 New York time) Regulus, the 1.3 magnitude brighter star of Leo constellation, is going to be occulted by the asteroid 163 Erigone. The unusual event, visible to the naked eye over NYC, can allow to measure the shape of the asteroid, with reaching a space resolution below the diffraction limit of the eye, and of all instruments not based on interferometry. Ultimately the aperture of the instrument is related to the amount of scintillation affecting the light curve of the occultation, limitating the accuracy of video recorded data. The asteroid profile scans the surface of the star at a velocity of 6 mas/s; the diameter of the star is about 1.3 mas and the detection of the stellar limb darkening signature is discussed, taking into consideration also the Fresnel fringes. New data reduction with R-OTE software of the 2005 Regulus occultation and simulations of the 2014 occultation with Fren_difl software are presented.

  19. Gravity waves above the Andes detected from GPS radio occultation temperature profiles: Jet mechanism?

    de la Torre, A.; Alexander, P.; Llamedo, P.; Menéndez, C.; Schmidt, T.; Wickert, J.

    2006-12-01

    A significant wave activity (WA) in the upper troposphere and lower stratosphere, mainly during winter, was detected at midlatitudes in the southern hemisphere (30-40S) above the Andes Range, from an analysis of Global Positioning System Radio Occultation (GPS RO) temperature profiles retrieved by CHAMP (CHAllenging Minisatellite Payload) and SAC-C (Satélite de Aplicaciones Científicas-C) Low Earth Orbit (LEO) satellites, between May 2001 and February 2006. The possible main gravity wave sources in this region are: i) orographic forcing, ii) geostrophic adjustment and iii) deep convection. The available vertical resolution of GPS RO soundings does not rule out any of these alternatives. Based on satellite imaginary, the WA enhancements cannot be attributed to deep convection events. Inertia-gravity waves (IGWs) could be generated after a geostrophic adjustment process, following a perturbation of the zonal jet situated above the Andes Mountains by mountain waves (MWs). The monthly WA intensity follows the zonal wind velocity strength according to its seasonal variability at jet altitudes. As the GPS-LEO lines of sight are roughly meridionally aligned and the morphology of the Andes at middle latitudes is predominantly north-south, it was possible to detect MWs as well as IGWs from GPS RO temperature profiles. This characteristic does not apply for other mountain range alignments. From the analysis of a numerical simulation at the time and location of a single RO event with very strong WA, two main modes of oscillation with horizontal wavelength around 40 and 200 km were identified. The first one is attributed to a MW and the second one to an IGW.

  20. The Treatment of the Occult in General Encyclopedias.

    Sonnenfeld, Gary F.

    This paper is a content analysis of three general encyclopedias, "Encyclopedia Americana" (EA), "Encyclopaedia Brittanica" (EB), and "World Book Encyclopedia" (WBC), which quantifies the treatment of the occult. Entries are selected from each by starting with the article "Occultism" and tracing all cross-references. Cross-references are likewise…

  1. Occult HCV in Egyptian volunteer blood donors

    Mostafa A. Amin 1, Kouka S. E. Abdel-Wahab 2 and Adel A.

    2013-01-01

    Full Text Available Objective: The study aims to investigate the risk of post-transfusion transmission of hepatitis c virus (HCV in the circumstances of occult HCV when anti-HCV is undetectable by ELISA and HCV-RNA is detected by RT-PCR in the plasma and or in peripheral blood mononuclear cells (PBMCs of donor blood and the recipients are immunocompromised. Patients & methods: The study covered 18 chronic renal failure patients (CRF [12 males (66.7% their age ranged from 28 to 65 years and 6 females (33.3 % their age ranged from 15 to 55 years] undergoing hemodialysis in Nile Hospital as part of their therapy have to receive blood transfusions (275 blood units for the first time. Commercial ELISA kits for anti-HCV and nested-RT-PCR (N-RT-PCR kits were used. Results: Anti-HCV was positive in one serum from the eighteen (5.5% poly transfused CRF patients at the end of the study while the seventeen sera were negative. This serum was also positive for HCV RNA by N-RT-PCR. Out of the 20 transfused blood units, one blood unit (three components were tested by blood banking anti-HCV negative by ELISA, were positive for HCV RNA by N-RT-PCR. The collective markers of this blood unit represent an occult HCV. The risk of acquiring post-transfusion HCV infection from an occult HCV blood unit is 5%. Real time PCR showed variation in the viral load of the serum of the infected CRF patient, the plasma of blood unit, the PBMCs of this blood unit whether activated by PHA-M or not.

  2. Stationary occultations from low Earth orbit

    Percival, Jeffrey W.

    1993-01-01

    The process of stationary lunar occultations is considered for observers in LEO. The orbit of the Hubble Space Telescope (HST) is used as a prototype. The noncoplanarity of the HST and lunar orbits disrupts many of the expected stationary events, and orbital drag complicates the prediction problem. In a typical year, the apparent speed of the lunar limb seen by the HST is slower than a typical ground-based event only about 0.7 percent of the time. The orbit prediction can be wrong by as much as 20 deg in 53 days, with most of the error lying in the plane of the orbit.

  3. Prevalence of occult hepatitis B virus infection

    Maria Luisa Gutiérrez-García; Conrado M Fernandez-Rodriguez; Jose Luis Lledo-Navarro; Ingrid Buhigas-Garcia

    2011-01-01

    Occult hepatitis B virus (HBV) infection (OBI) is characterized by the persistence of HBV DNA in the liver tissue in individuals negative for the HBV surface antigen. The prevalence of OBI is quite variable depending on the level of endemic disease in different parts of the world,the different assays utilized in the studies, and the different populations studied. Many studies have been carried out on OBI prevalence in different areas of the world and categories of individuals. The studies show that OBI prevalence seems to be higher among subjects at high risk for HBV infection and with liver disease than among individuals at low risk of infection and without liver disease.

  4. Retrieval Algorithms for the Halogen Occultation Experiment

    Thompson, Robert E.; Gordley, Larry L.

    2009-01-01

    The Halogen Occultation Experiment (HALOE) on the Upper Atmosphere Research Satellite (UARS) provided high quality measurements of key middle atmosphere constituents, aerosol characteristics, and temperature for 14 years (1991-2005). This report is an outline of the Level 2 retrieval algorithms, and it also describes the great care that was taken in characterizing the instrument prior to launch and throughout its mission life. It represents an historical record of the techniques used to analyze the data and of the steps that must be considered for the development of a similar experiment for future satellite missions.

  5. Localized magnetized Rossby structures under zonal shear flow in the ionospheric E-layer

    Kaladze, T.D. [Purple Mountain Observatory, Chinese Academy of Sciences, Nanjing 210008 (China) and I. Vekua Institute of Applied Mathematics of Tbilisi State University, 2 University str., 0143 Tbilisi (Georgia)]. E-mail: tamaz_kaladze@yahoo.com; Wu, D.J. [Purple Mountain Observatory, Chinese Academy of Sciences, Nanjing 210008 (China); Tsamalashvili, L.V. [I. Vekua Institute of Applied Mathematics of Tbilisi State University, 2 University str., 0143 Tbilisi (Georgia); Jandieri, G.V. [Physics Department, Georgian Technical University, 77 Kostava str., 0175 Tbilisi (Georgia)

    2007-05-21

    Taking into account nonlinear interaction of magnetized Rossby waves with zonal shear flow in the Earth's ionospheric E-layer modified by inhomogeneous geomagnetic field and sheared zonal flow Charney equation is obtained. The appropriate region of linear phase velocities is analyzed and the stability condition of zonal flows is obtained. In case of nonlinear regime the appropriate compatibility condition is obtained and its independence on zonal shear flows is shown. It is shown that zonal shear flow may support the existence of solitary vortical structures. Owing to carried out analysis different from dipole structures new class of nonlinear solitary vortical structures is found.

  6. A digital video system for observing and recording occultations

    Barry, M A; Pavlov, Hristo; Hanna, William; McEwan, Alistair; Filipovic, Miroslav

    2015-01-01

    Stellar occultations by asteroids and outer solar system bodies can offer ground based observers with modest telescopes and camera equipment the opportunity to probe the shape, size, atmosphere and attendant moons or rings of these distant objects. The essential requirements of the camera and recording equipment are: good quantum efficiency and low noise, minimal dead time between images, good horological faithfulness of the image time stamps, robustness of the recording to unexpected failure, and low cost. We describe the Astronomical Digital Video occultation observing and recording System (ADVS) which attempts to fulfil these requirements and compare the system with other reported camera and recorder systems. Five systems have been built, deployed and tested over the past three years, and we report on three representative occultation observations: one being a 9 +/-1.5 second occultation of the trans-Neptunian object 28978 Ixion (mv=15.2) at 3 seconds per frame, one being a 1.51 +/-0.017 second occultation ...

  7. Global variations of zonal mean ozone during stratospheric warming events

    Randel, William J.

    1993-01-01

    Eight years of Solar Backscatter Ultraviolet (SBUV) ozone data are examined to study zonal mean variations associated with stratospheric planetary wave (warming) events. These fluctuations are found to be nearly global in extent, with relatively large variations in the tropics, and coherent signatures reaching up to 50 deg in the opposite (summer) hemisphere. These ozone variations are a manifestation of the global circulation cells associated with stratospheric warming events; the ozone responds dynamically in the lower stratosphere to transport, and photochemically in the upper stratosphere to the circulation-induced temperature changes. The observed ozone variations in the tropics are of particular interest because transport is dominated by zonal-mean vertical motions (eddy flux divergences and mean meridional transports are negligible), and hence, substantial simplifications to the governing equations occur. The response of the atmosphere to these impulsive circulation changes provides a situation for robust estimates of the ozone-temperature sensitivity in the upper stratosphere.

  8. The stability of a zonally averaged thermohaline circulation model

    Schmidt, G A

    1995-01-01

    A combination of analytical and numerical techniques are used to efficiently determine the qualitative and quantitative behaviour of a one-basin zonally averaged thermohaline circulation ocean model. In contrast to earlier studies which use time stepping to find the steady solutions, the steady state equations are first solved directly to obtain the multiple equilibria under identical mixed boundary conditions. This approach is based on the differentiability of the governing equations and especially the convection scheme. A linear stability analysis is then performed, in which the normal modes and corresponding eigenvalues are found for the various equilibrium states. Resonant periodic solutions superimposed on these states are predicted for various types of forcing. The results are used to gain insight into the solutions obtained by Mysak, Stocker and Huang in a previous numerical study in which the eddy diffusivities were varied in a randomly forced one-basin zonally averaged model. Resonant stable oscillat...

  9. Statistical properties of Charney-Hasegawa-Mima zonal flows

    Anderson, Johan

    2015-01-01

    A theoretical interpretation of numerically generated probability density functions (PDFs) of intermittent plasma transport events in unforced zonal flows is provided within the Charney-Hasegawa-Mima (CHM) model. The governing equation is solved numerically with various prescribed density gradients that are designed to produce different configurations of parallel and anti-parallel streams. Long-lasting vortices form whose flow is governed by the zonal streams. It is found that the numerically generated PDFs can be matched with analytical predictions of PDFs based on the instanton method by removing the autocorrelations from the time series. In many instances the statistics generated by the CHM dynamics relaxes to Gaussian distributions for both the electrostatic and vorticity perturbations, whereas in areas with strong nonlinear interactions it is found that the PDFs are exponentially distributed.

  10. Statistical properties of Charney-Hasegawa-Mima zonal flows

    Anderson, Johan, E-mail: anderson.johan@gmail.com [Department of Earth and Space Sciences, Chalmers University of Technology, SE-412 96 Göteborg (Sweden); Botha, G. J. J. [Department of Mathematics and Information Sciences, Northumbria University, Newcastle Upon Tyne NE1 8ST (United Kingdom)

    2015-05-15

    A theoretical interpretation of numerically generated probability density functions (PDFs) of intermittent plasma transport events in unforced zonal flows is provided within the Charney-Hasegawa-Mima (CHM) model. The governing equation is solved numerically with various prescribed density gradients that are designed to produce different configurations of parallel and anti-parallel streams. Long-lasting vortices form whose flow is governed by the zonal streams. It is found that the numerically generated PDFs can be matched with analytical predictions of PDFs based on the instanton method by removing the autocorrelations from the time series. In many instances, the statistics generated by the CHM dynamics relaxes to Gaussian distributions for both the electrostatic and vorticity perturbations, whereas in areas with strong nonlinear interactions it is found that the PDFs are exponentially distributed.

  11. Coherent structures in ion temperature gradient turbulence-zonal flow

    Singh, Rameswar, E-mail: rameswar.singh@lpp.polytechnique.fr [Laboratoire de Physique des Plasmas, Ecole Polytechnique, Route de Saclay, 91128 Palaiseau Cedex (France); Institute for Plasma Research, Bhat, Gandhinagar 382 428 (India); Singh, R. [Institute for Plasma Research, Bhat, Gandhinagar 382 428 (India); WCI Center for Fusion Theory, National Fusion Research Institute, Daejeon 305-333 (Korea, Republic of); Kaw, P. [Institute for Plasma Research, Bhat, Gandhinagar 382 428 (India); Gürcan, Ö. D. [Laboratoire de Physique des Plasmas, Ecole Polytechnique, Route de Saclay, 91128 Palaiseau Cedex (France); Diamond, P. H. [WCI Center for Fusion Theory, National Fusion Research Institute, Daejeon 305-333 (Korea, Republic of); CMTFO and CASS, University of California, San Diego, California 92093 (United States)

    2014-10-15

    Nonlinear stationary structure formation in the coupled ion temperature gradient (ITG)-zonal flow system is investigated. The ITG turbulence is described by a wave-kinetic equation for the action density of the ITG mode, and the longer scale zonal mode is described by a dynamic equation for the m = n = 0 component of the potential. Two populations of trapped and untrapped drift wave trajectories are shown to exist in a moving frame of reference. This novel effect leads to the formation of nonlinear stationary structures. It is shown that the ITG turbulence can self-consistently sustain coherent, radially propagating modulation envelope structures such as solitons, shocks, and nonlinear wave trains.

  12. The zonal and global albedoes of the earth

    Henderson-Sellers, A.; A. J. Meadows

    2011-01-01

    Changes in global albedo of the Earth can depend on regional variations in reflectivity. We compare here three regional factors that have been considered capable of causing significant changes in global albedo, representing them approximately by zonal averages. Our calculations suggest that (1) large latitudinal changes in ice cover will have only a slight effect on the planetary albedo, and (2) latitudinal shifts in the cloud belts can produce significant changes in the planetary albedo.DO...

  13. Sonographic swelling of pronator quadratus muscle in patients with occult bone injury

    The disarranged fat stripe of the pronator quadratus muscle (PQ) on radiographs (the PQ sign) is reported to be predictive of subtle bone fractures. This study aimed to report the results of magnetic resonance imaging (MRI) study in the patients in whom bone injury was not radiographically detected around the wrist joint, and the PQ was sonographically swollen following acute trauma. We evaluated sonographically the PQ of 55 patients who showed normal radiographs following acute trauma. The sonographic appearance of the PQ was checked on both longitudinal and transverse images. On the longitudinal image, the probe was positioned along the flexor carpi radialis tendon. For the transverse image, we adopted the image of the same level in which the PQ of the unaffected hand showed maximal thickness. The PQ was considered to be swollen with disproportionate hyperechogenicity and/or thickening compared with the unaffected side at least in one of the two images. Of the 55 patients, 25 patients whose PQ was considered to be swollen underwent MRI study. PQ thickness in millimeters was retrospectively measured on longitudinal and transverse sonographic images. Twenty-three patients (92.0%) had occult bone injury, and two adult patients (8.0%) showed only wrist joint effusion on MRI. Among these 23, the distal radius was the most frequent location of the occult bone injury (20 patients; 9 [36.0%] with an occult fracture line and 11 [44.0%] with bone bruising). In longitudinal image, the mean value of the PQ thickness of affected hands was 6.2 (3.7–9.6 mm; standard deviation [SD], 1.5) and that of unaffected hands was 4.5 (2.3–6.7 mm; SD, 1.2), respectively. In transverse image, that of dominant and nondominant hands was 7.6 (4.6–13.2 mm; SD, 2.0) and 5.5 (3.6–7.5 mm; SD, 1.1), respectively. The mean difference in PQ thickness between affected and unaffected hands was 1.7 (0.1–5.0 mm; SD, 1.1) in longitudinal image and 2.0 (0.3–6.8 mm; SD, 1.7) in transverse image

  14. Radio occultation experiments with INAF-IRA radiotelescopes.

    Pluchino, S.; Schillirò, F.; Salerno, E.; Pupillo, G.

    The Radio Occultation research program performed at the Medicina and Noto Radioastronomical Stations of the Istituto Nazionale di Astrofisica (INAF) - Istituto di Radioastronomia (IRA) includes observations of spacecraft by satellite and satellite by satellite events. The Lunar Radio Occultation (LRO) part of the program consists in collecting data of the lunar Total Electron Content (TEC), at different limb longitudes and at different time, in order to study long term variation of the Moon's ionosphere. The LRO program started at Medicina in September 2006 with the observation of the European probe SMART-1 during its impact on the lunar soil. It proceeded in 2007 with the observation of the lunar occultations of Saturn and Venus, and with the observation of Mars in 2008. On this occasion the probes Cassini, Venus Express, Mars Express, Mars Reconaissance Orbiter and Mars Odissey were respectively occulted by the moon. On Dec 1st 2008 a Venus lunar occultation occurred. On that occasion we performed the first Italian-VLBI (I-VLBI) tracking experiment by detecting the carrier signals coming from the Venus Express (VEX) spacecraft with both the IRA radiotelescopes together with the Matera antenna of the Italian Space Agency. The second part of the radio occultation program includes the observation of satellite by satellite occultation events, as well as mutual occultations of Jupiter satellites. These events are referred to as mutual phenomena (PHEMU). These observations are aimed to measure the radio flux variation during the occultation and to derive surface spatial characteristics such as Io's hot spots. In this work preliminary results of the Radio Occultation program will be presented.

  15. The relevance of grid expansion under zonal markets

    The European electricity market design is based on zonal markets with uniform prices. Locational price signals within these zones - necessary to ensure long-term efficiency - are not provided. Specifically, if intra-zonal congestion occurs due to missing grid expansion, the market design is revealed as inherently incomplete. This might lead to severe, unwanted distortions of the electricity market, both in the short- and in the long-term. In this paper, we study these distortions with a specific focus on the impact of restricted grid expansion under zonal markets. For this, we use a long term fundamental dispatch and investment model of the European electricity system and gradually restrict the allowed expansion of the transmission grid per decade. We find that the combination of an incomplete market design and restricted grid expansion leads to a misallocation of generation capacities and the inability to transport electricity to where it is needed. Consequences are severe and lead to load curtailment of up to 2-3 %. Moreover, missing grid expansion makes it difficult and costly to reach envisaged energy targets in the power sector. Hence, we argue that in the likely event of restricted grid expansion, either administrative measures or - presumably more efficient - an adaptation of the current market design to include locational signals will become necessary.

  16. The relevance of grid expansion under zonal markets

    Bertsch, Joachim; Hagspiel, Simeon; Just, Lisa [ewi Energy Research and Scenarios gGmbH, Cologne (Germany); Cologne Univ. (Germany). Dept. of Economics; Brown, Tom [Frankfurt Institute of Advanced Studies (Germany)

    2015-12-15

    The European electricity market design is based on zonal markets with uniform prices. Locational price signals within these zones - necessary to ensure long-term efficiency - are not provided. Specifically, if intra-zonal congestion occurs due to missing grid expansion, the market design is revealed as inherently incomplete. This might lead to severe, unwanted distortions of the electricity market, both in the short- and in the long-term. In this paper, we study these distortions with a specific focus on the impact of restricted grid expansion under zonal markets. For this, we use a long term fundamental dispatch and investment model of the European electricity system and gradually restrict the allowed expansion of the transmission grid per decade. We find that the combination of an incomplete market design and restricted grid expansion leads to a misallocation of generation capacities and the inability to transport electricity to where it is needed. Consequences are severe and lead to load curtailment of up to 2-3 %. Moreover, missing grid expansion makes it difficult and costly to reach envisaged energy targets in the power sector. Hence, we argue that in the likely event of restricted grid expansion, either administrative measures or - presumably more efficient - an adaptation of the current market design to include locational signals will become necessary.

  17. Occult choriocarcinoma: Detection using radiolabeled monoclonal antibodies

    Occult choriocarcinoma, manifested only by an elevated B-hCG level, can be a difficult management problem. The authors evaluated the ability of I-131-labeled 5F9.3, a murine monoclonal antibody reactive with choriocarcinomas but not hCG, to detect foci of choriocarcinoma in five patients referred with elevated B-hCG levels but in whom the location of residual disease was uncertain. I-131 5F9.3, 0.5-1.0 mCi, was injected intravenously in each patient and images with dynamic background subtraction of TcHSA were obtained at later time points. In four patients chest studies were true positive (confirmed surgically in all), the chest CT scans in these patients had been interpreted as not definitely showing active disease. In the fifth patient no abnormal focus of uptake was seen and subsequent B-hCG levels normalized. In two of the patients with chest lesions, foci of abdominal uptake were seen that were not due to tumor. One of these patients had a partial small bowel obstruction; the other appeared to have a false-positive study. I-131 5F9.3 is a promising agent for the detection of occult choriocarcinomas

  18. Evaluation of occult fracture around the knee

    Injuries in the vicinity of the knee joint are often seen in daily medical care. Occult fractures are fractures which do not show up on roentgenograms in the first examination, but in follow-up examinations. In this study, we investigated 60 cases of occult fractures around the knee joint treated at our department which did not appear in initial roentgenograms. Their ages ranged from 15 to 96 years old, with a mean age of 71.5 years old. They consisted of eight men and 52 females. Fifty-nine cases were diagnosed by MRI. All samples were treated by conservative management. At week 8 from the first examination, symptoms were found to have disappeared in 82.1%. Fractures tend to occur easily in elderly women. More than 75% are caused by moderate external force, suggesting relation with osteoporosis. When elderly women fall, if swelling of the knee joint and hemarthrosis are seen, fractures should be suspected even if they do not appear on X-ray, and MRI should be useful for such diagnosis. (author)

  19. Processing GPS Occultation Data To Characterize Atmosphere

    Hajj, George; Kursinski, Emil; Leroy, Stephen; Lijima, Byron; de la Torre Juarez, Manuel; Romans, Larry; Ao, Chi

    2005-01-01

    GOAS [Global Positioning System (GPS) Occultation Analysis System] is a computer program that accepts signal-occultation data from GPS receivers aboard low-Earth-orbiting satellites and processes the data to characterize the terrestrial atmosphere and, in somewhat less comprehensive fashion, the ionosphere. GOAS is very robust and can be run in an unattended semi-operational processing mode. It features sophisticated retrieval algorithms that utilize the amplitudes and phases of the GPS signals. It incorporates a module that, using an assumed atmospheric refractivity profile, simulates the effects of the retrieval processing system, including the GPS receiver. GOAS utilizes the GIPSY software for precise determination of orbits as needed for calibration. The GOAS output for the Earth s troposphere and mid-to-lower stratosphere consists of high-resolution (<1 km) profiles of density, temperature, pressure, atmospheric refractivity, bending angles of signals, and water-vapor content versus altitude from the Earth s surface to an altitude of 30 km. The GOAS output for the ionosphere consists of electron-density profiles from an altitude of about 50 km to the altitude of a satellite, plus parameters related to the rapidly varying structure of the electron density, particularly in the E layer of the ionosphere.

  20. A Digital Video System for Observing and Recording Occultations

    Barry, M. A. Tony; Gault, Dave; Pavlov, Hristo; Hanna, William; McEwan, Alistair; Filipović, Miroslav D.

    2015-09-01

    Stellar occultations by asteroids and outer solar system bodies can offer ground based observers with modest telescopes and camera equipment the opportunity to probe the shape, size, atmosphere, and attendant moons or rings of these distant objects. The essential requirements of the camera and recording equipment are: good quantum efficiency and low noise; minimal dead time between images; good horological faithfulness of the image timestamps; robustness of the recording to unexpected failure; and low cost. We describe an occultation observing and recording system which attempts to fulfil these requirements and compare the system with other reported camera and recorder systems. Five systems have been built, deployed, and tested over the past three years, and we report on three representative occultation observations: one being a 9 ± 1.5 s occultation of the trans-Neptunian object 28978 Ixion (m v =15.2) at 3 seconds per frame; one being a 1.51 ± 0.017 s occultation of Deimos, the 12 km diameter satellite of Mars, at 30 frames per second; and one being a 11.04 ± 0.4 s occultation, recorded at 7.5 frames per second, of the main belt asteroid 361 Havnia, representing a low magnitude drop (Δm v = ~0.4) occultation.

  1. Asteroid occultations today and tomorrow: toward the GAIA era

    Tanga, P.; Delbo, M.

    2007-11-01

    Context: Observation of star occultations is a powerful tool to determine shapes and sizes of asteroids. This is key information necessary for studying the evolution of the asteroid belt and to calibrate indirect methods of size determination, such as the models used to analyze thermal infrared observations. Up to now, the observation of asteroid occultations is an activity essentially secured by amateur astronomers equipped with small, portable equipments. However, the accuracy of the available ephemeris prevents accurate predictions of the occultation events for objects smaller than ~100 km. Aims: We investigate current limits in predictability and observability of asteroid occultations, and we study their possible evolution in the future, when high accuracy asteroid orbits and star positions (such as those expected from the mission Gaia of the European Space Agency) will be available. Methods: We use a simple model for asteroid ephemeris uncertainties and numerical algorithms for estimating the limits imposed by the instruments, assuming realistic CCD performances and asteroid size distribution, to estimate the expected occultation rate under different conditions. Results: We show that high accuracy ephemerides which will be available in the future will extend toward much smaller asteroids the possibility of observing asteroid occultations, greatly increasing the number of events and objects involved. A complete set of size measurements down to ~10 km main belt asteroids could be obtained in a few years, provided that a small network of ground-based 1m telescopes are devoted to occultation studies.

  2. The occultation of Kappa Geminorum by Eros. [stellar occultation observed for asteroid size and shape

    Oleary, B.; Marsden, B. G.; Dragon, R.; Hauser, E.; Mcgrath, M.; Backus, P.; Robkoff, H.

    1976-01-01

    The paper discusses predictions and observations of the occultation of Kappa Gem by (433) Eros on January 24, 1975. Several positive and negative observations made in western New England are described. Local circumstances for the occultation are reconstructed, and the size and shape of Eros are determined analytically as well as graphically. The calculations yield two extremes for the cross section: a circle 23 km in diameter or a somewhat irregular figure 20 km by 6 or 7 km. Arguments based on the expected albedo of the asteroid suggest that the circle should be warped into an ellipse 21 by 13 km or that the irregular figure might be one component of a dumbbell-like profile.

  3. The atmosphere of Neptune: Results of radio occultation measurements with the Voyager 2 spacecraft

    Radio tracking data acquired during Voyager 2's occultation by Neptune have been used to study the thermal structure and composition of Neptune's troposphere and stratosphere. The data cover an altitude interval of about 250 km. A comparison with infrared observations indicates that the gas at the tropopause, which was observed near the 100 mbar level, consists of 77 to 85% hydrogen by number density with the remainder being mostly helium. A layer with a small refractivity scale height that was detected approximately 50 km below the tropopause, may be a region where the CH4 mixing ratio is decreasing with increasing altitude due to condensation effects. This interpretation leads to a CH4 mixing ratio of 1 to 2% by number density at the base of the layer where the pressure is approximately 1.7 bars. By assuming that the microwave absorption was caused by saturated NH3 vapor, one obtains a pressure, temperature, and NH3 mixing ratio of 6 bars, 130 K, and 600 parts per billion, respectively, at the lowest level where the radio link was detected. For internal consistency, this solution requires an atmospheric rotation period of 14.2 ± 0.5 hours near 60 degree North latitude which corresponds to a prograde zonal wind velocity of 170 ± 50 m/sec relative to the magnetic field

  4. Stratospheric NO and NO2 Abundances from ATMOS Solar-Occultation Measurements

    Newchurch, M. J.; Allen, M.; Gunson, M. R.; Salawitch, R. J.; Collins, G. B.; Huston, K. H.; Abbas, M. M.; Abrams, M. C.; Chang, A. Y.; Fahey, D. W.; Gao, R. S.; Irion, F. W.; Lowenstein, M.; Manney, G. L.; Michelsen, H. A.; Podolske, J. R.; Rinsland, C. P.; Zander, R.

    1996-01-01

    Using results from a time-dependent photochemical model to calculate the diurnal variation of NO and NO2, we have corrected Atmospheric Trace MOlecule Spectroscopy (ATMOS) solar-occultation retrievals of the NO and NO2 abundances at 90' solar zenith angle. Neglecting to adjust for the rapid variation of these gases across the terminator results in potential errors in retrieved profiles of approximately 20% for NO2 and greater than 100% for NC at altitudes below 25 km. Sensitivity analysis indicates that knowledge of the local 03 and temperature profiles, rather than zonal mean or climatological conditions of these quantities, is required to obtain reliable retrievals of NO and NO2 in the lower stratosphere. Extremely inaccurate 03 or temperature values at 20 km can result in 50% errors in retrieved NO or NO2. Mixing ratios of NO in the mid-latitude, lower stratosphere measured by ATMOS during the November 1994 ATLAS-3 mission compare favorably with in situ ER-2 observations, providing strong corroboration of the reliability of the adjusted space-borne measurements.

  5. Flight System Implementation of the Spacecraft Occulter System for Theia

    Tenerelli, Domenick; Theia

    2009-01-01

    The objective of the Theia program is to characterize Earth-like planets around nearby stars. Theia utilizes two formation-flying spacecraft in an L2 orbit - an observatory and a free flying occulter. Characterization involves looking for signs of life by observing molecular signatures and the presence of water vapor. A free flying occulter spacecraft provides starlight suppression by blocking the starlight while allowing planet light to pass. A diffraction limited monolithic optical telescope is provided for observing planet light passed by the occulter spacecraft. The occulter spacecraft and observatory are flown with a separation of 38, 700 km to 72,000 km (depending on telescope aperture). The Theia system design greatly simplifies design, manufacturing, modeling, and testing requirements compared to a stand-alone high performance internal coronagraph. Design advantages include having thermal/mechanical specifications approaching those of a conventional telescope requiring minimal actuator count. Standard materials and manufacturing approaches apply. End-to-end testing and facilities requirements are standard. The occulter is comprised of up to 30 petals constructed of a dimensionally stable material. Each petal is structurally reinforced for ground handling and testing purposes. An electro-mechanically actuated deployment utilizes standard space qualified mechanism designs to achieve up to a 50m deployed diameter. Multiple layers ensure performance over 5 years of micro-meteroid degradation. The occulter spacecraft is a modular design built of dimensionally stable composite material with 6 bays mounted to a propulsion sub-assembly. The occulter spacecraft uses ion thrusters to achieve its required delta-V over its lifetime and to maintain a position tolerance of 1 m with respect to the observatory. A traditional reaction wheel system is used to maintain orientation. The occulter and occulter spacecraft are compatible with the Atlas 5 launch vehicle.

  6. The Research and Education Collaborative Occultation Network: A System for Coordinated TNO Occultation Observations

    Buie, Marc W.; Keller, John M.

    2016-03-01

    We describe a new system and method for collecting coordinated occultation observations of trans-Neptunian objects (TNOs). Occultations by objects in the outer solar system are more difficult to predict due to their large distance and limited span of the astrometric data used to determine their orbits and positions. This project brings together the research and educational community into a unique citizen-science partnership to overcome the difficulties of observing these distant objects. The goal of the project is to get sizes and shapes for TNOs with diameters larger than 100 km. As a result of the system design it will also serve as a probe for binary systems with spatial separations as small as contact systems. Traditional occultation efforts strive to get a prediction sufficiently good to place mobile ground stations in the shadow track. Our system takes a new approach of setting up a large number of fixed observing stations and letting the shadows come to the network. The nominal spacing of the stations is 50 km so that we ensure two chords at our limiting size. The spread of the network is roughly 2000 km along a roughly north-south line in the western United States. The network contains 56 stations that are committed to the project and we get additional ad hoc support from International Occultation Timing Association members. At our minimum size, two stations will record an event while the other stations will be probing the inner regions for secondary events. Larger objects will get more chords and will allow determination of shape profiles. The stations are almost exclusively sited and associated with schools, usually at the 9-12 grade level. We present a full description of the system we have developed for the continued exploration of the Kuiper Belt.

  7. CT detection of occult pneumothorax in head trauma

    A prospective evaluation for occult pneumothorax was performed in 25 consecutive patients with serious head trauma by combining a limited chest CT examination with the emergency head CT examination. Of 21 pneuomothoraces present in 15 patients, 11 (52%) were found only by chest CT and were not identified clinically or by supine chest radiograph. Because of pending therapeutic measures, chest tubes were placed in nine of the 11 occult pneumothoraces, regardless of the volume. Chest CT proved itself as the most sensitive method for detection of occult pneumothorax, permitting early chest tube placement to prevent transition to a tension pneumothorax during subsequent mechanical ventilation or emergency surgery under general anesthesia

  8. The stellar occultation by Makemake on 2011 April 23

    Ortiz, J. L.; Sicardy, B.; Assafin, M.; Alvarez-Candal, A; Ivanov, V. D.; Camargo, J; Littlefair, S.; Unda-Sanzana, E.; Jehin, Emmanuel; Braga-Ribas, F.; Lellouch, E.; Morales, N.; Licandro, J.; Gil-Hutton, R.; Duffard, R.

    2011-01-01

    We have taken advantage of a stellar occultation by the dwarf planet Makemake on 2011 April 23, to determine several of its main physical properties. We present results from a multisite campaign with 8 positive occultation detections from 5 different sites, including data from the 8-m VLT and 3.5-m NTT telescopes in Chile, which have very high temporal resolution. Because the star was significantly fainter than Makemake (setting a record in the magnitude of a star whose occultation has been d...

  9. Asteroid Shape Models Refined By Stellar Occultation Silhouettes

    Durech, J.; Kaasalainen, M.

    2004-12-01

    We present shape models of asteroids 2 Pallas, 3 Juno, 39 Laetitia, 41 Daphne, 52 Europa, 85 Io, 129 Antigone, and 208 Lacrimosa derived from their lightcurves and stellar occultation silhouettes. Lightcurve inversion shape models and rotation states of those asteroids were already published. The occultation silhouettes give direct information about the size and shape of asteroid's projected cross-section. We process the lightcurve and occultation data simultaneously and derive more detailed shape models, remove possible ambiguities in the pole directions, and calibrate the models to absolute dimensions.

  10. Fecal Occult Blood Test and Gastrointestinal Parasitic Infection

    Majed H. Wakid

    2010-01-01

    Full Text Available Stool specimens of 1238 workers in western region of Saudi Arabia were examined for infection with intestinal parasites and for fecal occult blood (FOB to investigate the possibility that enteroparasites correlate to occult intestinal bleeding. Direct smears and formal ether techniques were used for detection of diagnostic stages of intestinal parasites. A commercially available guaiac test was used to detect fecal occult blood. 47.01% of the workers were infected with intestinal parasites including eight helminthes species and eight protozoan species. The results provided no significant evidence (P-value=0.143 that intestinal parasitic infection is in association with positive guaiac FOB test.

  11. The Uranus Occultation of 10 June 1979. I. The Rings

    Nicholson, P. D.; Matthews, K; Goldreich, P.

    1981-01-01

    Observations and analysis of a stellar occultation by the rings of Uranus on 10 June 1979 are presented. Occultations by rings 4, ɑ, β, y, δ, and є are identified, and radii and azimuths of the occulting segments in the plane of the rings calculated. Results for rings y and δ are consistent with the hypothesis (Elliot et al. 1978; Nicholson et ɑl. 1978) that these two rings are circular and coplanar, and an approximate upper limit of 8 X 10^(-5) is placed on the eccentricity of either ring...

  12. What can the occult do for you?

    Holwerda, B W

    2016-01-01

    Interstellar dust is still a dominant uncertainty in Astronomy, limiting precision in e.g., cosmological distance estimates and models of how light is re-processed within a galaxy. When a foreground galaxy serendipitously overlaps a more distant one, the latter backlights the dusty structures in the nearer foreground galaxy. Such an overlapping or occulting galaxy pair can be used to measure the distribution of dust in the closest galaxy with great accuracy. The STARSMOG program uses Hubble to map the distribution of dust in foreground galaxies in fine (<100 pc) detail. Integral Field Unit (IFU) observations will map the effective extinction curve, disentangling the role of fine-scale geometry and grain composition on the path of light through a galaxy. The overlapping galaxy technique promises to deliver a clear understanding of the dust in galaxies: geometry, a probability function of dimming as a function of galaxy mass and radius, and its dependence on wavelength.

  13. Occult hepatitis B virus infection in Egypt

    2015-01-01

    The emerging evidence of the potentially clinicalimportance of occult hepatitis B virus (HBV) infection(OBI) increases the interest in this topic. OBI mayimpact in several clinical contexts, which include thepossible transmission of the infection, the contributionto liver disease progression, the development ofhepatocellular carcinoma, and the risk of reactivation.There are several articles that have published on OBI inEgyptian populations. A review of MEDLINE databasewas undertaken for relevant articles to clarify theepidemiology of OBI in Egypt. HBV genotype D is theonly detectable genotype among Egyptian OBI patients.Higher rates of OBI reported among Egyptian chronicHCV, hemodialysis, children with malignant disorders, andcryptogenic liver disease patients. There is an evidenceof OBI reactivation after treatment with chemotherapy.The available data suggested that screening for OBI mustbe a routine practice in these groups of patients. Furtherstudies needed for better understand of the epidemiologyof OBI among Egyptian young generations after the eraof hepatitis B vaccination.

  14. Magnetic Resonance Imaging in occult spinal dysraphism

    A prospective study was carried out in 100 cases of suspected occult spinal dysraphic anomalies with Magnetic Resonance Imaging (MRI) in order to determine its diagnostic efficacy as the initial imaging modality. MR imaging provided accurate preoperative information in 91 out of 92 cases (98.9%). Some of the unusual and interesting findings in the series were: presence of intrinsic cord abnormality in 19 out of 21 cases (90.4%) with a normal plain radiography, 4 cases of diastematomyelia with a dermoid in the dorsal and lumbar region associated with syringohydromyelia, intradural fibrous/glial bands, syringo-hydromyelia/myelomalacia of the conus with tethered cord syndrome having a normally paced conus, and myelocystocele. It is concluded that MRI is an excellent primary diagnostic tool, together with a plain radiography, for complete preoperative evaluation of mid-line spinal anomalies. 14 refs., 3 tabs., 7 figs

  15. Paraneoplastic retinopathy associated with occult bladder cancer

    M Nivean

    2016-01-01

    Full Text Available The aim was to report the first case of cancer-associated retinopathy (CAR presenting before bladder cancer diagnosis. A 71-year-old woman with a history of bilateral vision loss underwent subsequent complete ophthalmic examination include a fluorescein angiography, full-field electroretinogram (ERG, serology including serum antibodies for CAR, and positron emission tomography-computed tomography (PET-CT scan. The patient was diagnosed with bladder carcinoma revealed by PET-CT. Timely recognition of this entity may be crucial for an increased patient survival thus adult onset progressive photoreceptor dysfunction, confirmed by ERG, should alert to a possible remote effect of known or occult malignancy. In the latter, PET-CT may be exploited as a powerful diagnostic tool.

  16. Paraneoplastic retinopathy associated with occult bladder cancer

    Nivean, M; Muttuvelu, Danson V; Afzelius, Pia Maria Tullia;

    2016-01-01

    The aim was to report the first case of cancer-associated retinopathy (CAR) presenting before bladder cancer diagnosis. A 71-year-old woman with a history of bilateral vision loss underwent subsequent complete ophthalmic examination include a fluorescein angiography, full-field electroretinogram...... (ERG), serology including serum antibodies for CAR, and positron emission tomography-computed tomography (PET-CT) scan. The patient was diagnosed with bladder carcinoma revealed by PET-CT. Timely recognition of this entity may be crucial for an increased patient survival thus adult onset progressive...... photoreceptor dysfunction, confirmed by ERG, should alert to a possible remote effect of known or occult malignancy. In the latter, PET-CT may be exploited as a powerful diagnostic tool....

  17. Verifying timestamps of occultation observation systems

    A., M; Gault, Dave; Bolt, Greg; McEwan, Alistair; Filipovic, Miroslav D; White, Graeme L

    2015-01-01

    We describe an image timestamp verification system to determine the exposure timing characteristics and continuity of images made by an imaging camera and recorder, with reference to Coordinated Universal Time (UTC). The original use was to verify the timestamps of stellar occultation recording systems, but the system is applicable to lunar flashes, planetary transits, sprite recording, or any area where reliable timestamps are required. The system offers good temporal resolution (down to 2 msec, referred to UTC) and provides exposure duration and interframe dead time information. The system uses inexpensive, off-the- shelf components, requires minimal assembly and requires no high-voltage components or connections. We also describe an application to load FITS (and other format) image files, which can decode the verification image timestamp. Source code, wiring diagrams and built applications are provided to aid the construction and use of the device.

  18. Effects of Zonal Wind on Stratospheric Ozone Variations over Nigeria

    Chidinma Okoro, Eucharia,

    2016-07-01

    The effects of zonal wind on stratospheric ozone variation over Nigeria have been studied. The areas covered in this study include; Maiduguri, Ikeja, Port-Harcourt, Calabar, Makurdi, Ilorin, Akure, Yola, Minna, Jos, Kano and Enugu in Nigeria, from 1986 to 2008. Zonal wind was computed from the iso-velocity map employing MATLAB software. The mean monthly variations of AAM and LOD at pressure levels of 20, 30 and 50 mb in the atmosphere depict a trend of maximum amplitude between April and September, and minimum amplitude between December and March. The trend observed in seasonal variation of O3 column data in the low latitude had maximum amount from May through August and minimum values from December through February. The mean monthly maximum O3 concentrations was found to be 284.70 Du (Kano) occurring in May 1989 while, an average monthly minimum O3 concentration was found to be 235.60 Du (Port-Harcourt and Calabar) occurring in January 1998. It has been established in this study that, the variation in atmospheric angular momentum (AAM) caused by variation of the universal time or length of day (LOD) transfer ozone (O3) by means of zonal wind from the upper troposphere to the lower stratosphere in the stations understudy. The strong effect of the pressure levels of the atmosphere on O3 variation could be attributed to its effect on the AAM and LOD. Variation in the LOD is significant in the tropics, suggesting that, the effects of the extra-tropical suction pump (ETSP) action is not the only driver responsible for O3 transportation from the tropics to extra-tropical zones. Consequently, these findings lead to a deduction that weather pattern alteration observed due to these changes could lead to climate change. Keywords: ozone variations; dynamical processes; harmattan wind; ETSP; and climatic variability

  19. Magnetic flux concentration and zonal flows in magnetorotational instability turbulence

    Accretion disks are likely threaded by external vertical magnetic flux, which enhances the level of turbulence via the magnetorotational instability (MRI). Using shearing-box simulations, we find that such external magnetic flux also strongly enhances the amplitude of banded radial density variations known as zonal flows. Moreover, we report that vertical magnetic flux is strongly concentrated toward low-density regions of the zonal flow. Mean vertical magnetic field can be more than doubled in low-density regions, and reduced to nearly zero in high-density regions in some cases. In ideal MHD, the scale on which magnetic flux concentrates can reach a few disk scale heights. In the non-ideal MHD regime with strong ambipolar diffusion, magnetic flux is concentrated into thin axisymmetric shells at some enhanced level, whose size is typically less than half a scale height. We show that magnetic flux concentration is closely related to the fact that the turbulent diffusivity of the MRI turbulence is anisotropic. In addition to a conventional Ohmic-like turbulent resistivity, we find that there is a correlation between the vertical velocity and horizontal magnetic field fluctuations that produces a mean electric field that acts to anti-diffuse the vertical magnetic flux. The anisotropic turbulent diffusivity has analogies to the Hall effect, and may have important implications for magnetic flux transport in accretion disks. The physical origin of magnetic flux concentration may be related to the development of channel flows followed by magnetic reconnection, which acts to decrease the mass-to-flux ratio in localized regions. The association of enhanced zonal flows with magnetic flux concentration may lead to global pressure bumps in protoplanetary disks that helps trap dust particles and facilitates planet formation.

  20. Longitudinal variation in zonal winds at subauroral regions: Possible mechanisms

    Wang, Hui; Lühr, Hermann

    2016-01-01

    Longitudinal differences in thermospheric zonal winds (ΔUy) are investigated in the subauroral region for different seasons and under solar maximum and medium conditions by using Challenging Minisatellite Payload observations. Prominent wave-1 longitudinal and diurnal variations of ΔUy are observed, along with an antiphase relationship between the Northern and Southern Hemispheres. These structures persist over the whole year and are independent of solar activity. ΔUy values are greater at nighttime than at daytime, and values in the south are greater than those in the north in local summer and winter. Model simulations confirm observed results in large-scale structures, and the nonzero dipole tilt is found to be vital for the longitudinal variation of the zonal wind. The neutral air pressure gradient caused by the day-night difference in solar heating is a major contributor to the observed ΔUy. The pressure effects are larger at nighttime than at daytime and larger in the Southern Hemisphere than in the Northern Hemisphere. Ion drag reduces the compatibility between the modeled and observed ΔUy as expected, with larger effects at nighttime than at daytime. Viscous force also reduces the compatibility between the modeled and observed ΔUy with greater effects at daytime, except at nighttime in the Southern Hemisphere. Similarly, the Coriolis force makes the difference between the modeled and observed ΔUy larger. The sum of these factors can explain, in general, the observed local time and hemispheric asymmetry features in longitudinal variation of the zonal wind.

  1. Occult breast carcinoma presenting as axillary metastases

    Purpose: Breast carcinoma presenting with axillary lymphadenopathy and no clinical or radiological evidence of a primary tumor is a rare presentation. We aimed to examine the management of the breast by observation, radiation therapy, or mastectomy. Methods and Materials: Departmental records from 1979 to 1996 of unknown primary presentations and cases of T0N1-2M0 breast carcinoma were reviewed to find cases of occult breast carcinoma presenting as axillary lymphadenopathy with no clinical or imaging evidence of a primary tumor. Results: There were 6047 presentations of breast carcinoma with 20 cases of occult breast carcinoma meeting the criteria. The breast was treated by observation in 6 cases, mastectomy in 2 cases, and radiotherapy to the intact breast in 12 cases. Eighty-three percent of patients (5 of 6 patients) who had observation of the breast had a local recurrence, compared to 25% who had radiotherapy to the intact breast (3 of 12 patients) and 0% who had a mastectomy (0 of 2 patients). The median recurrence-free survival was 7 months in patients who had observation of the breast, compared to 182 months in patients who had local treatment. Three of the 6 patients who underwent breast observation have died whereas 1 of the 14 who had local treatment have died, with a mean follow-up of 73 months. It was found that patients having observation of the breast had a poorer recurrence-free survival (p = 0.003) and overall survival (p = 0.05) compared to those having local treatment of the breast. Conclusions: Patients with such a presentation should have a complete physical examination, mammography, ultrasound, and MRI of the breasts. If there remains no evidence of a primary tumor, an axillary dissection should be carried out and the breast treated by radiotherapy or mastectomy. Observation of the breast is not a recommended option

  2. Intensity Scintillations in Planetary Ring Occultations: Simulations

    Marouf, E.

    2003-12-01

    A combined analytical and numerical simulation approach is used to investigate the first, second, and fourth statistical averages of the signal observed during a ring occultation experiment. The rings are modeled as a randomly blocked diffraction screen. The field behind the screen (the rings) assumes binary values: zero if located in the shadow area cast by ring particles and the full incident field otherwise. The stochastic geometry of the union of shadow areas cast behind the rings defines a so-called Boolean model. Either the random wavefront formed behind the screen or it's statistical averages can be propagated to an observer (a detector) some distance away from the diffraction screen. The parabolic approximation of the wave equation is used to model near-forward diffraction effects over the free-space path from the ring plane to the observation plane. The first and second moments were previously shown to correspond to the well-known coherent and scattered signal components observed during radio occultation experiments. Of particular interest here is the fourth moment of the random field at the observer, which determines the intensity scintillation index. Numerical simulations are used to investigate its behavior as a function of relevant model parameters, in particular, the ring particle radius and the Fresnel scale of observation. A monodispersion of ring particles is assumed to keep the model as simple as possible so as to investigate conditions under which the particle size may be recoverable from the intensity scintillation measurements. The model is also idealized to one-dimensional diffraction screen in order to speed up the computations; however, simulations of the more realistic two-dimensional diffraction screen models are also carried out.

  3. Vertical zonality of fractionated granite plutons reflected in zircon chemistry

    Breiter, Karel

    s. l : Universidad d Salamanca ; Escuela politécnica superior de Avila ; Universidad de Granada, 2011 - (Molina, J.; Scarrow, J.; Bea, F.; Montero, P.). s. 25-25 ISBN 978-84-694-5253-0. [Hutton Symposium on Granites and Related Rocks /7./. 04.07.2011-09.07.2011, Avila] Institutional research plan: CEZ:AV0Z30130516 Keywords : zircon * granite geochemistry * granite zonality * Cínovec * Beauvoir Subject RIV: DB - Geology ; Mineralogy http://www.seventh-hutton.org/meeting/Abstracts,_posters,_Lithos_Special_Issue_files/abstracts_book_Hutton_ISBN.pdf

  4. Zonal flow regimes in rotating anelastic spherical shells (Invited)

    Gastine, T.; Wicht, J.; Aurnou, J. M.; Heimpel, M. H.

    2013-12-01

    The surface zonal winds observed in the giant planets form a complex jet pattern with alternating prograde and retrograde direction. While the main equatorial band is prograde on the gas giants, both ice giants have a pronounced retrograde equatorial jet. The depth of these jets is however poorly known and highly debated. Theoretical scenarios range from "shallow models", that assume that these zonal flows are restricted to the outer stably stratified layer; to "deep models" that hypothesise that the surface winds are the signature of deep-seated convection. Most of the numerical models supporting the latter idea employed the Boussinesq approximation where compressibility effects are ignored. While this approximation is suitable for modelling the liquid iron core of terrestrial planets, this becomes questionable in the gas giants interiors, where density increases by several orders of magnitude. To tackle this problem, several numerical models using the "anelastic approximation" have been recently developed to study the compressibility effects while filtering out the fast acoustic waves. Here, we consider such anelastic models of rapidly-rotating spherical shells to explore the properties of the zonal winds in different regimes where either rotation or buoyancy dominates the force balance. We conduct several parameter studies to quantify the dependence of zonal flows on the background density stratification and the driving of convection. We find that the direction of the equatorial wind is controlled by the ratio of buoyancy and Coriolis force. The prograde equatorial band maintained by Reynolds stresses is found in the rotation-dominated regime. At low Ekman numbers, several alternating jets form at high latitude in a similar way to some previous Boussinesq calculations. In cases where buoyancy dominates Coriolis force, the angular momentum per unit mass is homogenised and the equatorial band is retrograde, reminiscent to those observed in the ice giants

  5. Generation of zonal flows in rotating fluids and magnetized plasmas

    Juul Rasmussen, J.; Garcia, O.E.; Naulin, V.;

    2006-01-01

    The spontaneous generation of large-scale flows by the rectification of small-scale turbulent fluctuations is of great importance both in geophysical flows and in magnetically confined plasmas. These flows regulate the turbulence and may set up effective transport barriers. In the present...... contribution the generation of zonal flows will be illustrated in a simple fluid experiment performed in a rotating container with radial symmetric bottom topography. An effective mixing that homogenizes the potential vorticity in the fluid layer will lead to the replacement of the high-potential vorticity...... analogy to large-scale flow generation in drift-wave turbulence dynamics in magnetized plasma is briefly discussed....

  6. Hydromagnetic constraints on deep zonal flow in the giant planets

    Kirk, R. L.; Stevenson, D. J.

    1987-01-01

    The observed zonal flows of the giant planets will, if they penetrate below the visible atmosphere, interact significantly with the planetary magnetic field outside the metallized core. The appropriate measure of this interaction is the Chandrasekhar number Q = H^2 /4πρνα^2 λ (H = radial component of the magnetic field, ν = eddy viscosity, λ = magnetic diffusivity, α^-1 = length scale on which λ varies); at depths where Q ≳ 1, the velocity will be forced to oscillate on a small lengt...

  7. Zonal drifts of irregularities imparted by meridional winds.

    Waldman, H.; Da Rosa, A. V.

    1973-01-01

    In a uniform ionosphere, meridional winds cause only meridional motions of irregularities. It is shown, however, that, if F-region irregularities are considered in a real ionosphere in which there is a highly conductive E-layer, zonal motions occur. During the day a substantial westward drift takes place, while at night the drift is eastward but smaller, owing to the much smaller E-layer conductivity. Thus, the effect of meridional winds is to impart a net westward drift to small irregularities in the ionization, provided such irregularities persist long enough.

  8. Forces on zonal flows in tokamak core turbulence

    The saturation of stationary zonal flows (ZF) in the core of a tokamak has been analyzed in numerical fluid turbulence computer studies. The model was chosen to properly represent the kinetic global plasma flows, i.e., undamped stationary toroidal or poloidal flows and Landau damped geodesic acoustic modes. Reasonable agreement with kinetic simulations in terms of magnitude of transport and occurrence of the Dimits shift was verified. Contrary to common perception, in the final saturated state of turbulence and ZFs, the customary perpendicular Reynolds stress continues to drive the ZFs. The force balance is established by the essentially quasilinear parallel Reynolds stress acting on the parallel return flows required by incompressibility. (author)

  9. Magnetic islands and spontaneous generation of zonal flows

    A study of saturated magnetic island equilibria on the basis of the resistive magneto-hydro-dynamic model is presented. A bifurcation in the sequence of equilibria is found as the ratio of the width of the current layer in the initial (non-reconnected) configuration over the island periodicity length reaches a critical threshold. Below this threshold, spontaneous generation of zonal flows occurs. This result is suggestive of a possible evolution of current sheets in magnetically confined plasmas and may be relevant to the understanding of the suppression of drift-wave turbulence and the formation of internal transport barriers in tokamak experiments. (letter to the editor)

  10. Magnetic islands and spontaneous generation of zonal flows

    Grasso, D [Burning Plasma Research Group, Department of Energetics, Politecnico di Torino (Italy); Margheriti, L [Department of Mathematics, Universita di Messina (Italy); Porcelli, F [Burning Plasma Research Group, Department of Energetics, Politecnico di Torino (Italy); Tebaldi, C [Burning Plasma Research Group, Department of Energetics, Politecnico di Torino (Italy)

    2006-09-15

    A study of saturated magnetic island equilibria on the basis of the resistive magneto-hydro-dynamic model is presented. A bifurcation in the sequence of equilibria is found as the ratio of the width of the current layer in the initial (non-reconnected) configuration over the island periodicity length reaches a critical threshold. Below this threshold, spontaneous generation of zonal flows occurs. This result is suggestive of a possible evolution of current sheets in magnetically confined plasmas and may be relevant to the understanding of the suppression of drift-wave turbulence and the formation of internal transport barriers in tokamak experiments. (letter to the editor)

  11. Association of preS/S Mutations with Occult Hepatitis B Virus (HBV) Infection in South Korea: Transmission Potential of Distinct Occult HBV Variants

    Hong Kim; Bum-Joon Kim

    2015-01-01

    Occult hepatitis B virus infection (HBV) is characterized by HBV DNA positivity but HBV surface antigen (HBsAg) negativity. Occult HBV infection is associated with a risk of HBV transmission through blood transfusion, hemodialysis, and liver transplantation. Furthermore, occult HBV infection contributes to the development of cirrhosis and hepatocellular carcinoma. We recently reported the characteristic molecular features of mutations in the preS/S regions among Korean individuals with occult...

  12. UARS Halogen Occultation Experiment (HALOE) Level 2 V001

    National Aeronautics and Space Administration — The HALOE home page on the WWW is http://haloe.gats-inc.com/home/index.php The Halogen Occultation Experiment (HALOE) on NASA's Upper Atmosphere Research Satellite...

  13. Asteroid occultations today and tomorrow: toward the GAIA era

    Tanga, P

    2008-01-01

    Context: Observation of star occultations is a powerful tool to determine shapes and sizes of asteroids. This is key information necessary for studying the evolution of the asteroid belt and to calibrate indirect methods of size determination, such as the models used to analyze thermal infrared observations. Up to now, the observation of asteroid occultations is an activity essentially secured by amateur astronomers equipped with small, portable equipments. However, the accuracy of the available ephemeris prevents accurate predictions of the occultation events for objects smaller than ~100 km. Aims: We investigate current limits in predictability and observability of asteroid occultations, and we study their possible evolution in the future, when high accuracy asteroid orbits and star positions (such as those expected from the mission Gaia of the European Space Agency) will be available. Methods: We use a simple model for asteroid ephemeris uncertainties and numerical algorithms for estimating the limits impo...

  14. An Outrigger Component for a Deployable Occulter System Project

    National Aeronautics and Space Administration — In Phase II, Roccor proposes to build upon the results of Phase I to increase the technology readiness level (TRL) of the NASA JPL deployable external occulter. An...

  15. Sizes, Shapes, and Satellites of Asteroids from Occultations

    Dunham, David W.; Herald, David; Preston, Steve; Timerson, Brad; Maley, Paul; Frappa, Eric; Hayamizu, Tsutomu; Talbot, John; Poro, Atila

    2016-01-01

    For 40 years, the sizes and shapes of many dozens of asteroids have been determined from observations of asteroidal occultations, and over a thousand high-precision positions of the asteroids relative to stars have been measured. Some of the first evidence for satellites of asteroids was obtained from the early efforts; now, the orbits and sizes of some satellites discovered by other means have been refined from occultation observations. Also, several close binary stars have been discovered, and the angular diameters of some stars have been measured from analysis of these observations. The International Occultation Timing Association (IOTA) coordinates this activity worldwide, from predicting and publicizing the events, to accurately timing the occultations from as many stations as possible, and publishing and archiving the observations.

  16. A Close Binary Star Resolved from Occultation by 87 Sylvia

    Lin, Chi-Long; Chen, W P; King, Sun-Kun; Lin, Hung-Chin; Bianco, F B; Lehner, M J; Coehlo, N K; Wang, J -H; Mondal, S; Alcock, C; Axelrod, T; Byun, Y -I; Cook, K H; Davé, R; De Pater, I; Porrata, R; Kim, D -W; Lee, T; Lissauer, J J; Marshall, S L; Rice, J A; Schwamb, M E; Wang, S -Y; Wen, C -Y

    2009-01-01

    The star BD+29 1748 was resolved to be a close binary from its occultation by the asteroid 87 Sylvia on 2006 December 18 UT. Four telescopes were used to observe this event at two sites separated by some 80 km apart. Two flux drops were observed at one site, whereas only one flux drop was detected at the other. From the long-term variation of Sylvia, we inferred the probable shape of the shadow during the occultation, and this in turn constrains the binary parameters: the two components of BD+29 1748 have a projected separation of 0.097" to 0.110" on the sky with a position angle 104 deg to 107 deg. The asteroid was clearly resolved with a size scale ranging from 130 to 290 km, as projected onto the occultation direction. No occultation was detected for either of the two known moonlets of 87 Sylvia.

  17. Analysis from Stellar Occultation and Lightcurve Observation of 582 Olympia

    Matsuoka, Y.; Okamoto, R.; Sugimoto, S.; Mayu Shibata; Watanabe, D.

    2012-05-01

    Our aim is to estimate 3D shape of an asteroid. We tried to find the shape of 582 Olympia. We conducted two observations: stellar occulation and lightcurve of an asteroid. We have observed lightcurves and occultations of several asteroid.

  18. Fecal Occult Blood Test and Fecal Immunochemical Test

    ... Visit Global Sites Search Help? Fecal Occult Blood Test and Fecal Immunochemical Test Share this page: Was this page helpful? Also ... Test Common Questions Ask Us Related Pages The Test How is it used? When is it ordered? ...

  19. Occult foreign bodies in the aero digestive tracts in infancy

    Saha, Somnath; Mishra, Saibal; Chakraborty, D. D.; Sengupta, Subhabrata; Mondal, A. R.

    2008-01-01

    Foreign body impaction in aero digestive tract in infancy is difficult to diagnose sometimes. In this review of five unusual cases of occult foreign body impaction in aero digestive tract has been presented and their management discussed

  20. Clues to occult cancer in patients with ischemic stroke.

    Suk Jae Kim

    Full Text Available BACKGROUND: We hypothesized that hidden malignancy could be detected in patients with cryptogenic stroke without active cancer when they showed the distinctive characteristics of cancer-related stroke. METHODS AND FINDINGS: Among 2,562 consecutive patients with acute ischemic stroke, patients with cryptogenic stroke were analyzed and categorized into two groups according to the presence of active cancer: cryptogenic stroke with active cancer (cancer-related stroke, CA-stroke group and without active cancer (CR-stroke group. Patients with active lung cancer without stroke were also recruited for comparison purposes (CA-control. Clinical factors, lesion patterns on diffusion-weighted MRI (DWI, and laboratory findings were analyzed among groups. A total of 348 patients with cryptogenic stroke were enrolled in this study. Among them, 71 (20.4% patients had active cancer at the time of stroke. The D-dimer levels were significantly higher in patients with CA-stroke than those with CR-stroke or CA-control (both p<0.001. Regarding lesion patterns, patients with CA-stroke mostly had multiple lesions in multiple vascular territories, while more than 80% of patients with CR-stroke had single/multiple lesions in a single vascular territory (P<0.001. D-dimer levels (OR 1.11 per 1 µg/mL increase; 95% CI 1.06-1.15; P<0.001 and DWI lesion patterns (OR 7.13; 95% CI 3.42-14.87; P<0.001 were independently associated with CA-stroke. Workup for hidden malignancy was performed during hospitalization in 10 patients who showed elevated D-dimer levels and multiple infarcts involving multiple vascular territories but had no known cancer, and it revealed hidden malignancies in all the patients. CONCLUSION: Patients with CA-stroke have distinctive D-dimer levels and lesion patterns. These characteristics can serve as clues to occult cancer in patients with cryptogenic stroke.

  1. The Return of Congenital Rickets, Are We Missing Occult Cases?

    Elidrissy, Abdelwahab T H

    2016-09-01

    Congenital rickets is the term given to fetus born with clinical features of rickets, but those born with biochemical evidence of rickets without obvious clinical features still can be considered occult congenital rickets. Some of the affected babies with this disease have the intrauterine rachitic environment, but a calcium trans-placental pump prevents the fetus from having clinical features of rickets. They may present with hypocalcemia few days after birth or later with more florid features of rickets. Congenital rickets cases born with florid features reported over the last 40 years are few and can be divided into two groups. The first due to severe maternal osteomalacia in which their bones were so decalcified to have enough calcium to be pumped to their fetus. Another group in which newborn babies were hypocalcemic due to other maternal diseases as malabsorption, celiac disease, pre-eclampsia, and prematurity. All inherited rickets cases per se, or as part of other syndromes can be considered congenital rickets. Most cases seen in our region are due to maternal vitamin D deficiency with symptoms becoming obvious when the infants are breastfed, or may present with hypocalcemic convulsions or craniotabes. This is a review of congenital rickets with the aim of shedding light on this potentially acute disease that needs more attention and awareness in the neonatal period to avoid rare serious complications as cardiomyopathy or myelofibrosis and the complications of hypocalcemic convulsions. Congenital rickets cases seen simulate a tip of an ice-burg and its prevention is an important issue, especially with the tremendous urbanization with tall buildings living in sun-deprived flats as the commonest type of residence leading to the increasing incidence of maternal osteomalacia and rickets. PMID:27245342

  2. Diagnostic value of mammography for occult breast cancer

    Objective: To evaluate the diagnostic value of mammography in occult breast cancer. Methods: 23 cases of non- palpable breast lesions were examined with stereotactic-guided or surgical biopsy. Results: Pathological diagnosis included ductal carcinoma in sim (7), infiltrating ductal carcinoma (5), lobular carcinoma in sim (2), carcinoma simplex (3), 4 intraductal papillary carcinoma (4), scirrhous carcinoma (1), metastatic adenocarcinoma (1) in the axilla. Conclusion: Mammography is a commonly used and effective method in diagnosis of occult breast cancer. (authors)

  3. New perspectives in occult hepatitis C virus infection

    Carreño, Vicente; Bartolomé, Javier; Castillo, Inmaculada; Quiroga, Juan Antonio

    2012-01-01

    Occult hepatitis C virus (HCV) infection, defined as the presence of HCV RNA in liver and in peripheral blood mononuclear cells (PBMCs) in the absence of detectable viral RNA in serum by standard assays, can be found in anti-HCV positive patients with normal serum levels of liver enzymes and in anti-HCV negative patients with persistently elevated liver enzymes of unknown etiology. Occult HCV infection is distributed worldwide and all HCV genotypes seem to be involved in this infection. Occul...

  4. Frequencies of occultations of stars by planets, satellites, and asteroids.

    O'Leary, B.

    1972-01-01

    Calculations show that several occultations of stars by the large satellites of the outer planets, Pluto, and the large asteroids could be observed each decade with existing equipment at earth-based telescopes. A systematic program of occultation predictions and observations is urged in order to improve our knowledge about the atmospheres, sizes, shapes, topography, and positions of these poorly understood bodies, in support of forthcoming spacecraft missions to the outer solar system.

  5. First Results From The Taiwanese-American Occultation Survey (TAOS)

    Zhang, Z; Bianco, F B; Lehner, M J; Coehlo, N K; Wang, J; Mondal, S; Alcock, C; Axelrod, T; Byun, Y; Chen, W P; Cook, K H; Dave, R; de Pater, I; Porrata, R; Kim, D; King, S; Lee, T; Lin, H; Lissauer, J J; Marshall, S L; Protopapas, P; Rice, J A; Schwamb, M E; Wang, S; Wen, C

    2008-08-22

    Results from the first two years of data from the Taiwanese-American Occultation Survey (TAOS) are presented. Stars have been monitored photometrically at 4 Hz or 5 Hz to search for occultations by small ({approx}3 km) Kuiper Belt Objects (KBOs). No statistically significant events were found, allowing us to present an upper bound to the size distribution of KBOs with diameters 0.5 km < D < 28 km.

  6. First Results From The Taiwanese-American Occultation Survey (TAOS)

    Zhang, Z -W; Lehner, M J; Coehlo, N K; Wang, J -H; Mondal, S; Alcock, C; Axelrod, T; Byun, Y -I; Chen, W -P; Cook, K H; Davé, R; De Pater, I; Porrata, R; Kim, D -W; King, S -K; Lee, T; Lin, H -C; Lissauer, J J; Marshall, S L; Protopapas, P; Rice, J A; Schwamb, M E; Wang, S -Y; Wen, C -Y

    2008-01-01

    Results from the first two years of data from the Taiwanese-American Occultation Survey (TAOS) are presented. Stars have been monitored photometrically at 4 Hz or 5 Hz to search for occultations by small (~3 km) Kuiper Belt Objects (KBOs). No statistically significant events were found, allowing us to present an upper bound to the size distribution of KBOs with diameters 0.5 km < D < 28 km.

  7. Zonal Flows Driven by Small-Scale Drift-Alfven Modes

    李德徽; 周登

    2011-01-01

    Generation of zonal flows by small-scale drift-Alfven modes is investigated by adopting the approach of parametric instability with the electron polarization drift included. The zonal mode can be excited by primary modes propagating at both electron and ion diamagnetic drift directions in contrast to the assertion in previous studies that only primary modes propagating in the ion diamagnetic drift directions can drive zonal instabilities. Generally, the growth rate of the driven zonal mode is in the same order as that in previous study. However, different from the previous work, the growth rate is no longer proportional to the difference between the diamagnetic drift frequencies of electrons and ions.

  8. Dynamics of zonal flows and self-regulating drift-wave turbulence

    We present a theory of zonal flow - drift wave dynamics. Zonal flows are generated by modulational instability of a drift wave spectrum, and are damped by collisions. Drift waves undergo random shearing-induced refraction, resulting in increased mean square radial wavenumber. Drift waves and zonal flows together form a simple dynamical system, which has a single stable fixed point. In this state, the fluctuation intensity and turbulent diffusivity are ultimately proportional to the collisional zonal flow damping. The implications of these results for transport models is discussed. (author)

  9. Fine Structure Zonal Flow Excitation by Beta-induced Alfven Eigenmode

    Qiu, Zhiyong; Zonca, Fulvio

    2016-01-01

    Nonlinear excitation of low frequency zonal structure (LFZS) by beta-induced Alfven eigenmode (BAE) is investigated using nonlinear gyrokinetic theory. It is found that electrostatic zonal flow (ZF), rather than zonal current, is preferentially excited by finite amplitude BAE. In addition to the well-known meso-scale radial envelope structure, ZF is also found to exhibit fine radial structure due to the localization of BAE with respect to mode rational surfaces. Specifically, the zonal electric field has an even mode structure at the rational surface where radial envelope peaks.

  10. Physical mechanism behind zonal-flow generation in drift-wave turbulence.

    Manz, P; Ramisch, M; Stroth, U

    2009-10-16

    The energetic interaction between drift-wave turbulence and zonal flows is studied experimentally in two-dimensional wave number space. The kinetic energy is found to be transferred nonlocally from the drift waves to the zonal flow. This confirms the theoretical prediction that the parametric-modulational instability is the driving mechanism of zonal flows. The physical mechanism of this nonlocal energetic interaction between and zonal flows and turbulent drift-wave eddies in relation to the suppression of turbulent transport is discussed. PMID:19905704

  11. Non-axisymmetric instabilities in discs with imposed zonal flows

    Vanon, R

    2016-01-01

    We conduct a linear stability calculation of an ideal Keplerian flow on which a sinusoidal zonal flow is imposed. The analysis uses the shearing sheet model and is carried out both in isothermal and adiabatic conditions, with and without self-gravity (SG). In the non-SG regime a structure in the potential vorticity (PV) leads to a non-axisymmetric Kelvin-Helmholtz (KH) instability; in the short-wavelength limit its growth rate agrees with the incompressible calculation by Lithwick (2007), which only considers perturbations elongated in the streamwise direction. The instability's strength is analysed as a function of the structure's properties, and zonal flows are found to be stable if their wavelength is $\\gtrsim 8H$, where $H$ is the disc's scale height, regardless of the value of the adiabatic index $\\gamma$. The non-axisymmetric KH instability can operate in Rayleigh-stable conditions, and it therefore represents the limiting factor to the structure's properties. Introducing SG triggers a second non-axisym...

  12. Zonal harmonics of the gravity field in DEF-variables.

    Aparicio, I.; Floría, L.

    In order to be in a position to take advantage of the linear and regular formulation and treatment of Celestial Mechanics problems, in a recent paper Sharaf & Saad (1997) have given an analytical expansion of the Earth's zonal potential in terms of Kustaanheimo-Stiefel (KS) regular elements (Kustaanheimo & Stiefel 1965; Stiefel & Scheifele 1971), putting special emphasis on the consideration of elliptic-type two-body orbits. In the present paper we carry out an application of the so-called focal method (Burdet 1969) to derive the expression, in terms of the linearizing DEF-variables (Deprit, Elipe & Ferrer 1994, S S 4.1), of any zonal harmonic of the gravitational field created by a central body, and obtain the corresponding equations of motion for any value of the eccentricity. To this end, we will follow a variant of the focal method canonical approach based on the (weakly) canonical extension of the projective-decomposition point-transformation proposed by these authors.

  13. Implementing Multidisciplinary and Multi-Zonal Applications Using MPI

    Fineberg, Samuel A.

    1995-01-01

    Multidisciplinary and multi-zonal applications are an important class of applications in the area of Computational Aerosciences. In these codes, two or more distinct parallel programs or copies of a single program are utilized to model a single problem. To support such applications, it is common to use a programming model where a program is divided into several single program multiple data stream (SPMD) applications, each of which solves the equations for a single physical discipline or grid zone. These SPMD applications are then bound together to form a single multidisciplinary or multi-zonal program in which the constituent parts communicate via point-to-point message passing routines. Unfortunately, simple message passing models, like Intel's NX library, only allow point-to-point and global communication within a single system-defined partition. This makes implementation of these applications quite difficult, if not impossible. In this report it is shown that the new Message Passing Interface (MPI) standard is a viable portable library for implementing the message passing portion of multidisciplinary applications. Further, with the extension of a portable loader, fully portable multidisciplinary application programs can be developed. Finally, the performance of MPI is compared to that of some native message passing libraries. This comparison shows that MPI can be implemented to deliver performance commensurate with native message libraries.

  14. Application of zonal model on indoor air sensor network design

    Chen, Y. Lisa; Wen, Jin

    2007-04-01

    Growing concerns over the safety of the indoor environment have made the use of sensors ubiquitous. Sensors that detect chemical and biological warfare agents can offer early warning of dangerous contaminants. However, current sensor system design is more informed by intuition and experience rather by systematic design. To develop a sensor system design methodology, a proper indoor airflow modeling approach is needed. Various indoor airflow modeling techniques, from complicated computational fluid dynamics approaches to simplified multi-zone approaches, exist in the literature. In this study, the effects of two airflow modeling techniques, multi-zone modeling technique and zonal modeling technique, on indoor air protection sensor system design are discussed. Common building attack scenarios, using a typical CBW agent, are simulated. Both multi-zone and zonal models are used to predict airflows and contaminant dispersion. Genetic Algorithm is then applied to optimize the sensor location and quantity. Differences in the sensor system design resulting from the two airflow models are discussed for a typical office environment and a large hall environment.

  15. Effective Mass in Rosenbluth-Hinton type zonal flows

    Sengupta, W

    2016-01-01

    An initial radial electric field, $E_r(0)$, in an axisymmetric tokamak, results in geodesic acoustic mode (GAM) oscillations. The GAMs Landau damp, resulting in a much smaller final residual electric field, $E_r(\\infty)$, and accompanying parallel zonal flows (Rosenbluth and Hinton, 1998 PRL 80, 724, hereafter RH). The phenomenon exhibits a large effective mass (inertia due to flows), with an enhancement of order the well-known RH factor. In apparent paradox, the final angular momentum in the RH parallel zonal flow is much smaller than the angular momentum expected from the well-known rapid precession of the trapped particle population in the final electric field. In addition, an effective mass calculated naively based on the rapid trapped particle (TP) precession is much larger than the RH factor. A drift kinetic calculation is presented showing that the mathematical origin of the extra mass factor is a shift, proportional to $E_r$, of the usual energy coordinates in phase space. Importantly, this shift cont...

  16. Possible occultation by Pluto from US East Coast

    Waagen, Elizabeth O.

    2012-06-01

    We have been asked to help disseminate the news of a possible occultation by Pluto visible to observers on the US East coast. Although the AAVSO does not ordinarily issue announcements of upcoming occultations, in this case the object is Pluto and the NASA New Horizons mission (http://www.nasa.gov/mission_pages/newhorizons/main/index.html) will be visiting Pluto in 2015. The information below has been supplied by Dr. Leslie Young (Southwest Research Institute), who is coordinating this observing campaign on Pluto. Dr. Young is also Deputy Project Scientist for the New Horizons mission. ALERT: Possible Pluto occultation Wednesday night (2012/06/14 03:28 UT) from US East coast. CONTACT: Leslie Young (layoung@boulder.swri.edu; work: 303-546-6057; skype: drpluto). Also see our planning pages in progress at http://wiki.boulder.swri.edu/mediawiki/index.php/2012-06-14_Pluto_occultation. Pluto's thin, nitrogen atmosphere is in vapor-pressure equilibrium with the surface ice, and changes seasonally. We've seen it double since 1988, and now we measure its pressure once or twice a year. The technique we use is stellar occultation, when a star passes behind Pluto's atmosphere. The atmosphere defocuses the starlight. By the timing of the fading of the star, we measure the pressure and temperature in Pluto's atmosphere at ~10 km resolution. MORE INFORMATION: See http://wiki.boulder.swri.edu/mediawiki/index.php/2012-06-14_Pluto_occultation.

  17. Earth Occultation Monitoring with the Fermi Gamma Ray Burst Monitor

    Wilson-Hodge, Colleen A.

    2014-01-01

    Using the Gamma Ray Burst Monitor (GBM) on-board Fermi, we are monitoring the hard X-ray/soft gamma ray sky using the Earth occultation technique (EOT). Each time a source in our catalog is occulted by (or exits occultation by) the Earth, we measure its flux using the change in count rates due to the occultation. Currently we are using CTIME data with 8 energy channels spanning 8 keV to 1 MeV for the GBM NaI detectors for daily monitoring. Light curves, updated daily, are available on our website http://heastro.phys.lsu.edu/gbm. Our software is also capable of performing the Earth occultation monitoring using up to 128 energy bands, or any combination of those bands, using our 128-channel, 4-s CSPEC data. The GBM BGO detectors, sensitive from about 200 keV to 40 keV, can also be used with this technique. In our standard application of the EOT, we use a catalog of sources to drive the measurements. To ensure that our catalog is complete, our team has developed an Earth occultation imaging method. In this talk, I will describe both techniques and the current data products available. I will highlight recent and important results from the GBM EOT, including the current status of our observations of hard X-ray variations in the Crab Nebula.

  18. Diagnostic strategy for occult hepatitis B virus infection

    Sara Ocana; Maria Luisa Casas; Ingrid Buhigas; Jose Luis Lledo

    2011-01-01

    In 2008, the European Association for the study of the liver (EASL) defined occult hepatitis B virus infection (OBI) as the "presence of hepatitis B virus (HBV) DNA in the liver (with detectable or undetectable HBV DNA in the serum) of individuals testing hepatitis B surface antigen (HBsAg) negative by currently available assays". Several aspects of occult HBV infection are still poorly understood, including the definition itself and a standardized approach for laboratory-based detection, which is the purpose of this review. The clinical significance of OBI has not yet been established; however, in terms of public health, the clinical importance arises from the risk of HBV transmission. Consequently, it is important to detect high-risk groups for occult HBV infection to prevent transmission. The main issue is, perhaps, to identify the target population for screening OBI. Viremia is very low or undetectable in occult HBV infection, even when the most sensitive methods are used, and the detection of the viral DNA reservoir in hepatocytes would provide the best evaluation of occult HBV prevalence in a defined set of patients. However, this diagnostic approach is obviously unsuitable: blood detection of occult hepatitis B requires assays of the highest sensitivity and specificity with a lower limit of detection < 10 IU/mL for HBV DNA and < 0.1 ng/mL for HBsAg.

  19. Diverse Applications of Occultation Data in Ozone Assimilation

    Markowitz, A.; Uttley, P.

    2005-01-01

    Ozone profiles from solar occultation instruments provide invaluable information that can be used to evaluate the quality of assimilated ozone fields, from case studies to long-term phenomena. Occultation data can also be applied to include physical constraints while developing components of an assimilation system. Conversely, assimilation of occultation data can help in their validation, and it provides a framework for evaluation of the impact of occultation data on constraining global ozone fields within models. We illustrate these diverse applications by a series of examples using the ozone assimilation system at NASA/Goddard. In a case study, low ozone in the lower stratosphere due to transport of air from the Tropics to northern high latitudes that was captured by assimilation of Aura Microwave Limb Sounder (MLS) and Solar Backscatter Ultraviolet (SBUV) data, was found to agree with SAGE III data. For long-term monitoring, the quality of a multi-year SBUV-only assimilation was evaluated using monthly-mean time series of POAM, HALOE, and SAGE I1 data. We found realism in the representation of the annual cycle in ozone and in some aspects of interannual variability. Assimilation of POAM data was shown to improve the representation of lower stratospheric ozone, especially over Antarctica. More recently, we assimilated ILAS II ozone data in order to help in their validation. Solar occultation data are used to estimate parameters in a new model for forecast error variances that is being developed. These examples demonstrate the importance of occultation data for ozone assimilation, and potential of assimilation to increase the impact and the value of occultation data.

  20. Not all occult papillary carcinomas are minimal

    Occult papillary carcinomas are characterized as small papillary tumors of less than 1.5 cm in maximum diameter, with or without bulky metastatic deposits in cervical nodes. The primary lesion is usually not palpable, and although the clinical behavior usually follows a benign course, tumors with unfavorable histologic features (invasiveness, multifocality) or extrathyroidal disease or a combination of both may not do so. In this report six cases are presented to illustrate this entity. No patient had a history of irradiation to the head or neck. All had primary lesions smaller than 1.5 cm. None had a palpable nodule or abnormal thyroid scan results, and the diagnosis of thyroid cancer was based on cervical lymph node or lung biopsy specimens, which revealed papillary thyroid cancer. All of the patients underwent total or near-total thyroidectomies and were found to have small, invasive papillary lesions with additional metastases to cervical nodes noted at the time of thyroidectomy. Adjunctive treatment consisted of a 5 mCi iodine-131 scan, ablative iodine-131 therapy, and suppression with L-thyroxine. Although distant metastasis to lung or other organs is uncommon and the mortality rate is low (as in larger papillary cancers), these invasive lesions--despite their small size--have a high propensity for recurrence and should be considered to behave more like encapsulated papillary tumors with extrathyroidal extension than like their small, unencapsulated intrathyroidal counterparts

  1. Occult celiac disease prevents penetrance of hemochromatosis

    Andreas Geier; Siegfried Matern; Carsten Gartung; Igor Theurl; Guenter Weiss; Frank Lammert; Christoph G. Dietrich; Ralf Weiskirchen; Heinz Zoller; Benita Hermanns

    2005-01-01

    AIM: To report a patient with C282Y homozygocity, depleted body iron and intestinal atrophy caused by celiac disease (CD) who experienced resolution of the enteropathy with subsequent normalization of iron metabolism upon glutenfree diet.METHODS: To obtain information on the tissue distribution and quantitative expression of proteins involved in duodenal iron trafficking, we determined the expression of divalent-metal transporter 1 (DMT1), ferroportin 1 (FP1) and transferrin receptor (TfR1) by means of immunohistochemistry and real-time PCR in duodenal biopsies of this patient.RESULTS: Whereas in hereditary hemochromatosis patients without CD, DMT1 expression was up-regulated leading to excessive uptake of iron, we identified a significant reduction in protein and mRNA expression of DMT1 as acompensatory mechanism in this patient with HH and CD.CONCLUSION: Occult CD may compensate tot increased DMT1 expression in a specific subset of individuals withhomozygous C282Y mutations in the hemochromatosis(HFE) gene, thus contributing to the low penetrance of HH.

  2. The Extinction Law in an Occulting Galaxy

    Berlind, Andreas A; Pogge, R W; Sellgren, K; Berlind, Andreas A.

    1997-01-01

    We measure the extinction law in a galaxy's spiral arm and interarm regions using a visual and infrared (BVRJHK) imaging study of the interacting galaxies NGC 2207 and IC 2163. This is an overlapping spiral galaxy pair in which NGC 2207 partially occults IC 2163. This geometry enables us to directly measure the extinction of light from the background galaxy as it passes through the disk of the foreground galaxy. We measure the extinction as a function of wavelength, and find that there is less extinction in the optical bands than expected from a normal Galactic extinction law. This deviation is significantly larger in the interarm region than in the spiral arm. The extinction curve in the spiral arm resembles a Milky Way $R_V=5.0$ dust model and the interarm extinction curve is flatter (``greyer'') still. We examine the effect of scattering of background galaxy light into the line of sight and find that it is negligible. We also examine the effect of an unresolved patchy dust distribution using a simple two-c...

  3. Celestial shadows eclipses, transits, and occultations

    Westfall, John

    2015-01-01

    Much of what is known about the universe comes from the study of celestial shadows—eclipses, transits, and occultations.  The most dramatic are total eclipses of the Sun, which constitute one of the most dramatic and awe-inspiring events of nature.  Though once a source of consternation or dread, solar eclipses now lead thousands of amateur astronomers and eclipse-chasers to travel to remote points on the globe to savor their beauty and the adrenaline-rush of experiencing totality, and were long the only source of information about the hauntingly beautiful chromosphere and corona of the Sun.   Long before Columbus, the curved shadow of the Earth on the Moon during a lunar eclipse revealed that we inhabit a round world. The rare and wonderful transits of Venus, which occur as it passes between the Earth and the Sun, inspired eighteenth century expeditions to measure the distance from the Earth to the Sun, while the recent transits of 2004 and 2012 were the most widely observed ever--and still produced re...

  4. Global nature of zonal flow due to the finite band width

    The spectral effects of both micro-scale electron temperature gradient driven turbulence and zonal flow on the zonal flow generation are investigated theoretically and computationally based on the Hasegawa-Mima turbulence equation. As the minimum model describing the most primary spectral feature, we have developed an eight-wave interaction model which includes two sets of the conventional four-wave coupling systems with adjacent radial spectral difference of dkx. It is found that the zonal flow is characterized by a global nature with an enhancement of growth rate γq, namely, global zonal flow eigen-mode, which is attributed to the appearance of new cross mode couplings due to the finite band width of zonal flow. This is qualitatively different from the monochromatic character of zonal flow described in the conventional four-wave coupling model. Direct numerical simulations of the Hasegawa-Mima equation with a zonal flow spectral structure have clearly proven the analytical results by employing a rigorous spectral code. The calculations further show that the global zonal mode is not only governed by the spectral structure of pump waves, but also their phase relation

  5. Recognition of Historical Records Using Gabor and Zonal Features

    Soumya A

    2015-08-01

    Full Text Available The paper addresses the automation of the task of an epigraphist in reading and deciphering inscriptions. The automation steps include Pre-processing, Segmentation, Feature Extraction and Recognition. Preprocessing involves, enhancement of degraded ancient document images which is achieved through Spatial filtering methods, followed by binarization of the enhanced image. Segmentation is carried out using Drop Fall and Water Reservoir approaches, to obtain sampled characters. Next Gabor and Zonal features are extracted for the sampled characters, and stored as feature vectors for training. Artificial Neural Network (ANN is trained with these feature vectors and later used for classification of new test characters. Finally the classified characters are mapped to characters of modern form. The system showed good results when tested on the nearly 150 samples of ancient Kannada epigraphs from Ashoka and Hoysala periods. An average Recognition accuracy of 80.2% for Ashoka period and 75.6% for Hoysala period is achieved.

  6. Residual zonal flows in tokamaks and stellarators at arbitrary wavelengths

    Monreal, Pedro; Calvo, Iván; Sánchez, Edilberto; Parra, Félix I.; Bustos, Andrés; Könies, Axel; Kleiber, Ralf; Görler, Tobias

    2016-04-01

    In the linear collisionless limit, a zonal potential perturbation in a toroidal plasma relaxes, in general, to a non-zero residual value. Expressions for the residual value in tokamak and stellarator geometries, and for arbitrary wavelengths, are derived. These expressions involve averages over the lowest order particle trajectories, that typically cannot be evaluated analytically. In this work, an efficient numerical method for the evaluation of such expressions is reported. It is shown that this method is faster than direct gyrokinetic simulations performed with the Gene and EUTERPE codes. Calculations of the residual value in stellarators are provided for much shorter wavelengths than previously available in the literature. Electrons must be treated kinetically in stellarators because, unlike in tokamaks, kinetic electrons modify the residual value even at long wavelengths. This effect, that had already been predicted theoretically, is confirmed by gyrokinetic simulations.

  7. Residual zonal flows in tokamaks and stellarators at arbitrary wavelengths

    Monreal, P; Sánchez, E; Parra, F I; Bustos, A; Könies, A; Kleiber, R; Görler, T

    2015-01-01

    In the linear collisionless limit, a zonal potential perturbation in a toroidal plasma relaxes, in general, to a non-zero residual value. Expressions for the residual value in tokamak and stellarator geometries, and for arbitrary wavelengths, are derived. These expressions involve averages over the lowest order particle trajectories, that typically cannot be evaluated analytically. In this work, an efficient numerical method for the evaluation of such expressions is reported. It is shown that this method is faster than direct gyrokinetic simulations. Calculations of the residual value in stellarators are provided for much shorter wavelengths than previously available in the literature. Electrons must be treated kinetically in stellarators because, unlike in tokamaks, kinetic electrons modify the residual value even at long wavelengths. This effect, that had already been predicted theoretically, is confirmed by gyrokinetic simulations.

  8. The Taiwanese-American Occultation Survey: The Multi-Telescope Robotic Observatory

    Lehner, M J; Wang, J -H; Marshall, S L; Schwamb, M E; Zhang, Z -W; Bianco, F B; Giammarco, J; Porrata, R; Alcock, C; Axelrod, T; Byun, Y -I; Chen, W P; Cook, K H; Davé, R; King, S -K; Lee, T; Lin, H -C; Wang, S -Y

    2008-01-01

    The Taiwanese-American Occultation Survey (TAOS) operates four telescopes to search for occultations of stars by Kuiper Belt Objects. This paper provides a detailed description of the TAOS multi-telescope system.

  9. NOAA Climate Data Record (CDR) of Zonal Mean Ozone Binary Database of Profiles (BDBP), version 1.0

    National Oceanic and Atmospheric Administration, Department of Commerce — This NOAA Climate Data Record (CDR) of Zonal Mean Ozone Binary Database of Profiles (BDBP) dataset is a vertically resolved, global, gap-free and zonal mean dataset...

  10. Radiotherapy of the central nervous system in acute leukemia

    The central nervous system (CNS) is a site of occult and overt involvement with acute lymphoblastic leukemia (ALL) in children. Prophylactic treatment of the cranial and spinal meninges can significantly reduce the incidence of CNS relapse. This review addresses the issues associated with the role of radiation therapy in the treatment of the CNS in ALL.20 references

  11. Mutations Associated With Occult Hepatitis B in HIV-Positive South Africans

    Powell, Eleanor A.; Gededzha, Maemu P; Rentz, Michael; Rakgole, Nare J.; Selabe, Selokela G.; Seleise, Tebogo A.; Mphahlele, M Jeffrey; Blackard, Jason T.

    2014-01-01

    Occult hepatitis B is characterized by the absence of hepatitis B surface antigen (HBsAg) but the presence of HBV DNA. Because diagnosis of hepatitis B virus (HBV) typically includes HBsAg detection, occult HBV remains largely undiagnosed. Occult HBV is associated with increased risk of hepatocellular carcinoma, reactivation to chronic HBV during immune suppression, and transmission during blood transfusion and liver transplant. The mechanisms leading to occult HBV infection are unclear, alth...

  12. The occultation of Surrealism: a study of the relationship between Bretonian Surrealism and western esotericism

    Hanegraaff, W.J.; Bauduin, T.M.

    2012-01-01

    It has been said that Surrealism was nothing if not deeply involved with occultism and Western esotericism. Others claim that there was no such involvement or even that Surrealism was directly opposed to the occult and esoteric. ‘The occultation of Surrealism’ offers a fresh view of this complex and important debate that has remained unresolved until now, and seeks to account for such differing opinions about the supposedly occult character of Surrealism, specifically under the leadership of ...

  13. Probing Planetary Formation and Evolution Through Occultations

    Rodriguez, Joseph E.; KELT Team

    2016-01-01

    The circumstellar environments of young stellar objects (YSOs) involve complex dynamical interactions between dust and gas that directly influence the formation of planets. However, our understanding of the evolution from the material in the circumstellar disk to the thousands of planetary systems discovered to date, is limited. One means to better constrain the size, mass, and composition of this planet-forming material is to observe a YSO being eclipsed by its circumstellar disk. Through this dissertation project, we are discovering and characterizing both disk eclipsing systems and exoplanets using the Kilodegree Extremely Little Telescope (KELT) project. KELT is a photometric survey for transiting planets orbiting bright stars (8 < V < 11); such bright planet host targets are well-suited for atmospheric characterization of the planets. KELT has discovered 15 planets transiting stars brighter than V ~11 to date. I will present some of the recently discovered planets from the survey and discuss their potential to advance our understanding of planetary atmospheres. In addition, KELT provides photometric monitoring of ~3 million stars, presenting the opportunity to perform multi-year studies of stellar variability generally and rare disk occultations specifically. Using time-series photometry from KELT we are conducting the Disk Eclipse Search with KELT (DESK) survey to look for disk eclipsing events, specifically in young stellar associations. To date, the survey has discovered and analyzed four previously unknown large dimming events around the stars RW Aurigae, V409 Tau, AA Tau, and TYC 2505-672-1, the latter now representing the longest-period eclipsing object known (period ~ 69 years). I will describe our results for planet atmosphere characterization and for protoplanetary disk structure and composition, and discuss how to search for these kinds of systems in future surveys such as LSST.

  14. Occult sporadic insulinoma:Localization and surgical strategy

    Bassam Abboud; Joe Boujaoude

    2008-01-01

    Insulinomas continue to pose a diagnostic challenge to physicians,surgeons and radiologists alike.Most are intrapancreatic,benign and solitary.Biochemical diagnosis is obtained and imaging techniques to localize lesions continue to evolve.Surgical resection is the treatment of choice.Despite all efforts,an occult insulinoma (occult insulinoma refers to a biochemically proven tumor with indeterminate anatomical site before operation) may still be encountered.New localization preoperative techniques decreases occult cases and the knowledge of the site of the mass before surgery allows to determine whether enucleation of the tumor or pancreatic resection is likely to be required and whether the tumor is amenable to removal via a laparoscopic approach.In absence of preoperative localization and intraoperative detection of an insulinoma,blind pancreatic resection is not recommended.

  15. Probing the Martian atmosphere with MAVEN/IUVS stellar occultations

    Gröller, H.; Yelle, R. V.; Koskinen, T. T.; Montmessin, F.; Lacombe, G.; Schneider, N. M.; Deighan, J.; Stewart, A. I. F.; Jain, S. K.; Chaffin, M. S.; Crismani, M. M. J.; Stiepen, A.; Lefèvre, F.; McClintock, W. E.; Clarke, J. T.; Holsclaw, G. M.; Mahaffy, P. R.; Bougher, S. W.; Jakosky, B. M.

    2015-11-01

    The first campaign of stellar occultations with the Imaging Ultraviolet Spectrograph (IUVS) instrument on board of Mars Atmosphere and Volatile EvolutioN (MAVEN) mission was executed between 24 and 26 March 2015. From this campaign 13 occultations are used to retrieve CO2 and O2 number densities in the altitude range between 100 and 150 km. Observations probe primarily the low-latitude regions on the nightside of the planet, just past the dawn and dusk terminator. Calculation of temperature from the CO2 density profiles reveals that the lower thermosphere is significantly cooler than predicted by the models in the Mars Climate Database. A systematically cold layer with temperatures of 105-120 K is seen in the occultations at a pressure level around 7 × 10-6 Pa.

  16. GRAS radio occultation on-board of Metop

    von Engeln, A.; Andres, Y.; Marquardt, C.; Sancho, F.

    2011-01-01

    The GRAS radio occultation instrument is flying on Metop-A and belongs to the EPS (EUMETSAT Polar System). GRAS observes GPS satellites in occultation. Within this work, validation of GRAS closed-loop bending angle data against co-located ECMWF profiles extracted from model fields and occultations from the COSMIC constellation of radio occultation instruments is shown. Results confirm the high data quality and robustness, where GRAS shows lower bending angle noise against ECMWF than COSMIC and in terms of occultations per day, one GRAS ≈ two COSMIC satellites. This is partly due to the operational setup of EPS. For the investigation we focus on two observation periods where updates in the ECMWF (March 2009) and COSMIC processing (October 2009) have improved the statistics further. Bending angles biases agree to within 0.5% against ECMWF and to within 0.1% against COSMIC after the updates for altitudes between 8 and 40 km. In addition, we also analyze the impact of the Metop orbit processing on the derived GRAS bending angle data, where different GPS and Metop orbit solutions are analyzed. Results show that a batch based orbit processing would improve in particular the bending angle bias behavior at higher altitudes. Requirements for the operational processing of GRAS data are briefly outlined, options to ease the use of other positioning system satellites in the near future are discussed. A simplified analysis on the observation of several of these systems, e.g. GPS and Galileo, from one platform shows that about 16% of occultations are found within 300 km, ±3 h, thus providing similar information. A constellation of 2 GRAS like instruments would have only about 10% close-by.

  17. Quantification of structural uncertainty in climate data records from GPS radio occultation

    A. K. Steiner

    2012-10-01

    Full Text Available Global Positioning System (GPS radio occultation (RO provides continuous observations of the Earth's atmosphere since 2001 with global coverage, all-weather capability, and high accuracy and vertical resolution in the upper troposphere and lower stratosphere (UTLS. Precise time measurements enable long-term stability but careful processing is needed. Here we provide climate-oriented atmospheric scientists with multicenter-based results on the long-term stability of RO climatological fields for trend studies. We quantify the structural uncertainty of atmospheric trends estimated from the RO record, which arises from current processing schemes of six international RO processing centers, DMI Copenhagen, EUM Darmstadt, GFZ Potsdam, JPL Pasadena, UCAR Boulder, and WEGC Graz. Monthly-mean zonal-mean fields of bending angle, refractivity, dry pressure, dry geopotential height, and dry temperature from the CHAMP mission are compared for September 2001 to September 2008. We find that structural uncertainty is lowest in the tropics and mid-latitudes (50° S to 50° N from 8 km to 25 km for all inspected RO variables. In this region, the structural uncertainty in trends over 7 yr is <0.03% f or bending angle, refractivity, and pressure, <3 m for geopotential height of pressure levels, and <0.06 K for temperature; low enough for detecting a climate change signal within about a decade. Larger structural uncertainty above about 25 km and at high latitudes is attributable to differences in the processing schemes, which undergo continuous improvements. Though current use of RO for reliable climate trend assessment is bound to 50° S to 50° N, our results show that quality, consistency, and reproducibility are favorable in the UTLS for the establishment of a climate benchmark record.

  18. Forthcoming Occultations of Astrometric Radio Sources by Planets

    L'vov, Victor; Malkin, Zinovy; Tsekmeister, Svetlana

    2010-01-01

    Astrometric observations of radio source occultations by solar system bodies may be of large interest for testing gravity theories, dynamical astronomy, and planetary physics. In this paper, we present an updated list of the occultations of astrometric radio sources by planets expected in the coming years. Such events, like solar eclipses, generally speaking can only be observed in a limited region. A map of the shadow path is provided for the events that will occurr in regions with several VLBI stations and hence will be the most interesting for radio astronomy experiments.

  19. An occultation of the inner Seyfert nucleus of NGC 4151

    The brightness of the unresolved nucleus of NGC 4151 was monitored over five months in 1983. Variations of ≅ 0.1 mag/day were observed in the U-band and no significant variation was found of the -OIII] 5007 A emission line. However, an event that was observed on the nights of the 10/11 and 11/12 February 1983 in the continuum around 5672 A has all the characteristics of an occultation. It is proposed that an inner synchrotron nucleus of ≅ 3 a.u. diameter was occulted by an opaque cloud ≅ 6 a.u. across on those two nights

  20. [Pitfalls in the diagnosis of occult elbow fractures in children].

    Courvoisier, A; Calvelli, N; Bourgeois, E; Eid, A; Griffet, J

    2016-08-01

    Elbow injuries are frequent but occult fractures are difficult to diagnose on x-rays. However, any delay in the diagnosis may severely impair the prognosis of some fractures. Simple tips may help the clinician read x-rays properly and avoid the classical pitfalls of elbow injuries in children. The chronology of appearance of ossification nuclei around the elbow is important to distinguish normal features from abnormality. Drawing simple geometric constructions on the x-rays may clarify most occult elbow fractures in children. PMID:27345552

  1. Presentation of Axillary Metastases from Occult Breast Carcinoma

    Xin Wang

    2007-01-01

    Axillary presentation from occult breast cancer is uncommon and continues to be a diagnostic and therapeutic challenge to physicians.Once the diagnosis of adenocarcinoma metastatic to an axillary lymph node has been confirmed,a preoperative workup should be done.The current experience is based on several relatively small retrospective reviews and case reports.It is difficult to determine the best management of occult breast cancer.However,treatmenl of axillary Iymph node dissection is recommended for local control and complete staging information.Treatment of breast should be a choice between breast conservation with whole-breast radiotherapy and mastectomy.Adjuvant systemic treatment should be offered.

  2. Status of the Transneptunian Automated Occultation Survey (TAOS II)

    Lehner, Matthew J.; Wang, Shiang Yu; Reyes-Ruiz, Mauricio; Chu, You Hua; Lee, William; Zhang, Zhi Wei; Cook, Kem H.; Norton, Timothy; Szentgyorgyi, Andrew; Alcock, Charles

    2015-11-01

    The Transneptunian Automated Occultation Survey (TAOS II) will aim to detect occultations of stars by small (~1 km diameter) objects in the Kuiper Belt and beyond. Such events are very rare (field of view and a high speed camera comprising CMOS imagers, the survey will monitor 10,000 stars simultaneously with all three telescopes at a nominal readout cadence of 20 Hz. Construction of the site began in the fall of 2013. We present here an update on the status of the TAOS II survey, including the site development, camera fabrication, and project schedule.

  3. YOHKOH remnants: partially occulted flares in hard X-rays

    M. Tomczak

    2009-01-01

    Flares being partially occulted by the solar limb, are the best reservoir of our knowledge about hard X-ray loop-top sources. Recently, the survey of partially occulted flares observed by the RHESSI has been published (Krucker & Lin 2008). The extensive YOHKOH database still awaits such activities. This work is an attempt to fill this gap. Among from 1286 flares in the YOHKOH Hard X-ray Telescope Flare Catalogue, for which the hard X-ray images had been enclosed, we identified 98 events that ...

  4. Interaction among different spatio-temporal scale fluctuations through zonal flows

    Zonal flows generated by fluctuations on some scale are expected to affect fluctuations on other different spatial-temporal scales in addition to regulating their own fluctuation. As an example, here we discuss ITG turbulence embedded in a small scale ETG-driven zonal flow based on 3-dimensional gyro-fluid simulations. At first, we identified the ETG-driven zonal spectrum and found that the zonal flows are enhanced in higher pressure and lower magnetic shear plasma, leading to a self-organized high energy state. Further, we found a new suppression mechanism of the long wavelength ITG mode by the small-scale ETG-driven zonal flows, namely the radially non-local mode coupling and the associated energy transfer. Besides the role of suppression of ITG turbulence, we have for the first time observed intermittent and/or bursting behavior in the ion heat transport originating from the complicated mutual interaction among EGT-driven zonal flows, ITG turbulence, and the associated ITG-driven zonal flows. (author)

  5. Generation of a Bending Angle Radio Occultation Climatology (BAROCLIM and its use in radio occultation retrievals

    B. Scherllin-Pirscher

    2014-08-01

    Full Text Available In this paper, we introduce a bending angle radio occultation climatology (BAROCLIM based on Formosat-3/COSMIC (F3C data. This climatology represents the monthly-mean atmospheric state from 2006 to 2012. Bending angles from radio occultation (RO measurements are obtained from the accumulation of the change in the raypath direction of Global Positioning System (GPS signals. Best quality of these near-vertical profiles is found from the middle troposphere up to the mesosphere. Beside RO bending angles we also use data from the Mass Spectrometer and Incoherent Scatter Radar (MSIS model to expand BAROCLIM in a spectral model, which (theoretically reaches from the surface up to infinity. Due to the very high quality of BAROCLIM up to the mesosphere, it can be used to detect deficiencies in current state-of-the-art analysis and reanalysis products from numerical weather prediction (NWP centers. For bending angles derived from European Centre for Medium-Range Weather Forecasts (ECMWF analysis fields from 2006 to 2012, e.g., we find a positive bias of 0.5% to % at 40 km, which increases to more than 2% at 50 km. BAROCLIM can also be used as a priori information in RO profile retrievals. In contrast to other a priori information (i.e., MSIS we find that the use of BAROCLIM better preserves the mean of raw RO measurements. Global statistics of statistically optimized bending angle and refractivity profiles also confirm that BAROCLIM outperforms MSIS. These results clearly demonstrate the utility of BAROCLIM.

  6. Theoretical performance of solar coronagraphs using sharp-edged or apodized circular external occulters

    Aime, C.

    2013-10-01

    Context. This study focuses on an instrument able to monitor the corona close to the solar limb. Aims: We study the performance of externally occulted solar coronagraphs. We compute the shape of the umbra and penumbra produced by the occulter at the entrance aperture of the telescope and compare levels of rejection obtained for a circular occulter with a sharp or smooth transmission at the edge. Methods: We show that the umbral pattern in an externally occulted coronagraph can be written as a convolution product between the occulter diffraction pattern and an image of the Sun. We then focus on the analysis to circular symmetric occulters. We first derive an analytical expression using two Lommel series for the Fresnel diffraction pattern produced by a sharp-edged circular occulter. Two different expressions are used for inside and outside the occulter's geometric shadow. We verify that a numerical approach that directly solves the Huygens-Fresnel integral gives the same result. This suggests that the numerical computation can be used for a circular occulter with any variable transmission. Results: With the objective of observing the solar corona a few minutes from limb, a sharp-edged circular occulter of a few meters cannot produce an umbra darker than 10-4 of the direct sunlight. The same occulter, having an apodization zone of a few percent of the diameter (3 cm for a 1.5 m occulter), darkers the umbra down to 10-8 of the direct sunlight for linear transmission and to 10-12 for Sonine or cosine bell transmissions. An investigation for an apodized occulter with manufacturing defaults is quickly performed. Conclusions: It has been possible to numerically demonstrate the large superiority of apodized circular occulters with respect to the sharp-edged ones. These occulters allow the theoretical observation of the very limb-close corona with not yet obtained contrast ratios.

  7. Dynamics of Zonal Flows: Failure of Wave-Kinetic Theory, and New Geometrical Optics Approximations

    Parker, Jeffrey B

    2016-01-01

    The self-organization of turbulence into regular zonal flows can be fruitfully investigated with quasilinear methods and statistical descriptions. A wave kinetic equation that assumes asymptotically large-scale zonal flows is pathological. From an exact description of quasilinear dynamics emerges two better geometrical optics approximations. These involve not only the mean flow shear but also the second and third derivative of the mean flow. One approximation takes the form of a new wave kinetic equation, but is only valid when the zonal flow is quasi-static and wave action is conserved.

  8. Fluid simulation of tokamak ion temperature gradient turbulence with zonal flow closure model

    Yamagishi, Osamu; Sugama, Hideo

    2016-03-01

    Nonlinear fluid simulation of turbulence driven by ion temperature gradient modes in the tokamak fluxtube configuration is performed by combining two different closure models. One model is a gyrofluid model by Beer and Hammett [Phys. Plasmas 3, 4046 (1996)], and the other is a closure model to reproduce the kinetic zonal flow response [Sugama et al., Phys. Plasmas 14, 022502 (2007)]. By including the zonal flow closure, generation of zonal flows, significant reduction in energy transport, reproduction of the gyrokinetic transport level, and nonlinear upshift on the critical value of gradient scale length are observed.

  9. Oh Glorious Geometry: Eclipses, Transits, and Occultations

    Sinclair, R. M.

    2016-01-01

    Astronomical objects are like a grand clockwork in the sky; they follow steady patterns in time. However, these bright objects we see are not just points of light but have finite dimensions and thus can get in each other's way. As a result, some stars puzzle us by brightening or dimming, or the Sun can frighten us by going out unexpectedly when something else blocks its light. There is nothing unusual about these eclipses, occultations, or transits—they are demonstrations of simple physics—and we take some for granted, like the rotation of Earth moving us into darkness each night. The periodic dimming of a bright star worried mankind for millennia and helped give astronomy a shove. And unexpected events, like a solar or lunar eclipse, can inspire awe and change the course of history. Now that we can observe through telescopes and travel by proxy throughout the solar system, we find the universe is rife with shadow and light shows. Those taking place within our solar system have been useful to astronomy (like the recent transits of Venus or the ever-present eclipses of the Jovian satellites), and were of considerable popular interest, allowing us to think beyond the confines of Earth. Now we detect distant exoplanets transiting their parent stars, announcing the presence of other solar systems in our corner of the Galaxy and changing the discussion about life elsewhere in the universe from mere speculation to plausible possibility. Distant galaxies can make visible ever-further galaxies by forming Einstein rings, allowing us to see behind them and make the structure of the universe more evident. This paper will discuss these phenomena, from those visible easily on Earth to those that can now be seen for the first time from probes in space. We will also discuss how this has expanded popular knowledge of the universe we live in. This paper is illustrated by a number of examples ranging from eclipses and transits throughout the solar system and the nearby stars to

  10. Is Occult Obscure Gastrointestinal Bleeding a Definite Indication for Capsule Endoscopy? A Retrospective Analysis of Diagnostic Yield in Patients with Occult versus Overt Bleeding

    Ikue Watari; Shiro Oka; Shinji Tanaka; Makoto Nakano; Taiki Aoyama; Shigeto Yoshida; Kazuaki Chayama

    2013-01-01

    Background/Aim. Usefulness of capsule endoscopy (CE) for diagnosing small-bowel lesions in patients with obscure gastrointestinal bleeding (OGIB) has been reported. Most reports have addressed the clinical features of overt OGIB, with few addressing occult OGIB. We aimed to clarify whether occult OGIB is a definite indication for CE. Methods. We retrospectively compared the cases of 102 patients with occult OGIB and 325 patients with overt OGIB, all having undergone CE. The diagnostic yield o...

  11. Occultations of stars by solar system objects. VIII - Occultations of catalog stars by asteroids, planets, Titan, and Triton in 1990 and 1991

    Wasserman, L. H.; Bowell, E.; Millis, R. L.

    1990-01-01

    Predictions are given for occultations of catalog stars by asteroids, planets, Titan, and Triton in 1990 and 1991. The predictions are based on a computerized comparison of the occulting bodies' ephemerides and nine major star catalogs. The search is complete for all numbered asteroids whose angular diameters exceed 0.08 arcsec during the search years. Preliminary ground tracks are shown for the more favorable occultations.

  12. Occult hepatitis B among Iranian hepatitis C patients

    Ahmad shavakhi

    2009-02-01

    Full Text Available

    • BACKGROUND: Occult hepatitis B is defined as presence of HBV DNA in tissue or serum without hepatitis B surface antigen. The aim of this study is to determine frequency of occult hepatitis B among hepatitis C patients in Tehran and compare the route of transmission and liver enzymes between positive and negative HBV DNA patients.
    • METHODS: In a cross sectional study, serum of 103 hepatitis C cases (79.6% men and 20.4% women were analyzed for s, x and core genes via a nested polymerase chain reaction technique.
    • RESULTS: HBV DNA was detectable in serum of 20 patients (19.4%. No significant difference in age, sex and route of transmission were seen in HBV DNA positive and negative patients. In HBV DNA positive and negative groups, mean of AST was 73, 47 (p < 0.05 and mean of ALT was 76 and 36 respectively (p < 0.05.
    • CONCLUSION: Occult hepatitis B was observed in a considerable number of hepatitis C patients in Tehran. It was associated with elevation in liver enzyme but was not related to route of transmission.
    • KEY WORD: Occult hepatitis B, hepatitis C, cirrhosis.

  13. Counseling the Occult-Involved Student: Guidelines and Suggestions.

    Carmichael, Karla D.

    1993-01-01

    Contends that counselors working with public school students needs to be aware of the four main levels of involvement in the occult (fun-and-games, dabblers, serious involvement, and criminal involvement). Each of the four levels is described, warning signs are identified, and the counselor's role is explained as one of support and prevention. (NB)

  14. Radio occultation bending angle anomalies during tropical cyclones

    R. Biondi

    2011-02-01

    Full Text Available The tropical deep convection affects the radiation balance of the atmosphere changing the water vapor mixing ratio and the temperature of the upper troposphere lower stratosphere. The aim of this work is to better understand these processes and to investigate if severe storms leave a significant signature in radio occultation profiles in the tropical tropopause layer. Using tropical cyclone best track database and data from different GPS radio occultation missions (COSMIC, GRACE, CHAMP, SACC and GPSMET, we selected 1194 profiles in a time window of 3 h and a space window of 300 km from the eye of the cyclone. We show that the bending angle anomaly of a GPS radio occultation signal is typically larger than the climatology in the upper troposphere and lower stratosphere and that a double tropopause during deep convection can easily be detected using this technique. Comparisons with co-located radiosondes, climatology of tropopause altitudes and GOES analyses are also shown to support the hypothesis that the bending angle anomaly can be used as an indicator of convective towers. The results are discussed in connection to the GPS radio occultation receiver which will be part of the Atomic Clock Ensemble in Space (ACES payload on the International Space Station.

  15. Pulmonary tumor embolism syndrome from occult colonic adenocarcinoma

    Heithaus, Robert Evans; Hitchcock, Michael A.; Guileyardo, Joseph M.

    2013-01-01

    Pulmonary tumor embolism syndrome is a rare phenomenon that can occur in patients who have an occult neoplasm that metastasizes. We describe a case of an elderly woman with an undiagnosed colon cancer who suffered from respiratory distress and compromised pulmonary blood flow from micrometastasis in the pulmonary arteries.

  16. Occult Dirofilariosis in Dogs of North Eastern Region in India

    Sonjoy Kumar-Borthakur

    2015-10-01

    Full Text Available Background: The North Eastern Region in India is endemic for canine heartworm disease but in clinics accurate diagnosis is some times difficult. The aim of the present study was to determine the prevalence of occult infections for heartworm disease in canine in two geographical regions of North Eastern India.Methods: A total of 782 numbers of three categories of dogs namely, working dogs of military and paramilitary forces, pet dogs and stray dogs were screened for the presence of heartworm infection from August 2011 to July, 2012 in Guwahati (Assam and Aizawl (Mizoram. Conventional, immunological and molecular techniques were followed for this epidemiological study. The criteria to determine the occult heartworm cases were based on the dif­ferences between heartworm positive cases in PCR test and antigen ELISA test.Results: The findings revealed an overall 22.69 percent occult case. The working dogs had highest prevalence (60% followed by pet (29.16% and stray dogs (17.75%.Conclusion: The highest percentage of occult heartworm infection was present in working dogs maintained under military or paramilitary forces. 

  17. Rossby-Khantadze electromagnetic planetary waves driven by sheared zonal winds in the E-layer ionosphere

    Futatani, S. [Department of Computer Applications in Science and Engineering (CASE), Barcelona Supercomputing Center, Barcelona (Spain); Horton, W. [Applied Research Laboratory and Institute for Fusion Studies, The University of Texas at Austin, Austin, Texas 78758 (United States); Kahlon, L. Z. [Department of Physics, Forman Christian College, Ferozepur Road, Lahore 54600 (Pakistan); Kaladze, T. D. [Physics Department, Government College University, Lahore 54000 (Pakistan); I. Vekua Institute of Applied Mathematics, Tbilisi State University, 2 University str., 0186 Tbilisi, Georgia (United States)

    2015-01-15

    Nonlinear simulations of electromagnetic Rossby and Khantadze planetary waves in the presence of a shearless and sheared zonal flows in the weakly ionized ionospheric E-layer are carried out. The simulations show that the nonlinear action of the vortex structures keeps the solitary character in the presence of shearless zonal winds as well as the ideal solutions of solitary vortex in the absence of zonal winds. In the presence of sheared zonal winds, the zonal flows result in breaking into separate multiple smaller pieces. A passively convected scalar field is shown to clarify the transport associated with the vortices. The work shows that the zonal shear flows provide an energy source into the vortex structure according to the shear rate of the zonal winds.

  18. Rossby-Khantadze electromagnetic planetary waves driven by sheared zonal winds in the E-layer ionosphere

    Nonlinear simulations of electromagnetic Rossby and Khantadze planetary waves in the presence of a shearless and sheared zonal flows in the weakly ionized ionospheric E-layer are carried out. The simulations show that the nonlinear action of the vortex structures keeps the solitary character in the presence of shearless zonal winds as well as the ideal solutions of solitary vortex in the absence of zonal winds. In the presence of sheared zonal winds, the zonal flows result in breaking into separate multiple smaller pieces. A passively convected scalar field is shown to clarify the transport associated with the vortices. The work shows that the zonal shear flows provide an energy source into the vortex structure according to the shear rate of the zonal winds

  19. Rossby-Khantadze electromagnetic planetary waves driven by sheared zonal winds in the E-layer ionosphere

    Futatani, S.; Horton, W.; Kahlon, L. Z.; Kaladze, T. D.

    2015-01-01

    Nonlinear simulations of electromagnetic Rossby and Khantadze planetary waves in the presence of a shearless and sheared zonal flows in the weakly ionized ionospheric E-layer are carried out. The simulations show that the nonlinear action of the vortex structures keeps the solitary character in the presence of shearless zonal winds as well as the ideal solutions of solitary vortex in the absence of zonal winds. In the presence of sheared zonal winds, the zonal flows result in breaking into separate multiple smaller pieces. A passively convected scalar field is shown to clarify the transport associated with the vortices. The work shows that the zonal shear flows provide an energy source into the vortex structure according to the shear rate of the zonal winds.

  20. Zonal superrotation above Venus' cloud base induced by the semidiurnal tide and the mean meridional circulation

    Hou, Arthur Y.; Goody, Richard M.; Fels, Stephen B.

    1990-01-01

    The equilibrium zonal wind structure resulting from the interaction of the semidiurnal tide and the mean meridional circulation driven by the zonally averaged solar heating above the Venus cloud base were calculated. The results show that the tidal mechanism proposed by Fels and Lindzen (1974) can account for a substantial fraction (and possibly all) of the increase of the equatorial wind speed above the cloud base. Above the cloud tops, tidal deceleration may be too small to produce the zonal wind decrease with height inferred from thermal data. Tidal forcing does not explain the superrotation below the clouds, and additional eddy sources are needed to account for the zonal wind structure at mid and high latitudes.

  1. TOMS/EP UV Aerosol Index Daily and Monthly Zonal Means V008

    National Aeronautics and Space Administration — This data product contains TOMS/EP UV Aerosol Index Daily and Monthly Zonal Means Version 8 data in ASCII format. (The shortname for this Level-3 Earth Probe TOMS...

  2. Evaluation of Sub-Zonal Airflow Models for the Prediction of Local Interior Boundary Conditions

    Steskens, Paul W. M. H.; Janssen, Hans; Rode, Carsten

    2013-01-01

    transfer coefficients near the building component for the analyzed cases. The relatively short computation time and flexibility of the sub-zonal model makes the application attractive for transient simulation of heat, air and moisture transport in buildings. However, the availability of appropriate...... applicability of the sub-zonal airflow model to predict the local indoor environmental conditions, as well as the local surface transfer coefficients near building components. Two test cases were analyzed for, respectively, natural and forced convection in a room. The simulation results predicted from the sub......-zonal airflow models are compared to experimental data and numerical computational fluid dynamics (CFD) results. The study shows that sub-zonal models combined with an appropriate surface transfer coefficient model are able to give reliable predictions of the local indoor environmental conditions and surface...

  3. Regulation of electron temperature gradient turbulence by zonal flows driven by trapped electron modes

    Asahi, Y., E-mail: y.asahi@nr.titech.ac.jp; Tsutsui, H.; Tsuji-Iio, S. [Tokyo Institute of Technology, Tokyo 152-8550 (Japan); Ishizawa, A.; Watanabe, T.-H. [National Institute for Fusion Science, Gifu 509-5292 (Japan)

    2014-05-15

    Turbulent transport caused by electron temperature gradient (ETG) modes was investigated by means of gyrokinetic simulations. It was found that the ETG turbulence can be regulated by meso-scale zonal flows driven by trapped electron modes (TEMs), which are excited with much smaller growth rates than those of ETG modes. The zonal flows of which radial wavelengths are in between the ion and the electron banana widths are not shielded by trapped ions nor electrons, and hence they are effectively driven by the TEMs. It was also shown that an E × B shearing rate of the TEM-driven zonal flows is larger than or comparable to the growth rates of long-wavelength ETG modes and TEMs, which make a main contribution to the turbulent transport before excitation of the zonal flows.

  4. Zonal jets in equilibrating baroclinic instability on the polar beta-plane: experiments with altimetry

    Matulka, A M

    2015-01-01

    Results from the laboratory experiments on the evolution of baroclinically unstable flows generated in a rotating tank with topographic beta-effect are presented. We study zonal jets of alternating direction which occur in these flows. The primary system we model includes lighter fluid in the South and heavier fluid in the North with resulting slow meridional circulation and fast mean zonal motion. In a two-layer system the velocity shear between the layers results in baroclinic instability which equilibrates with time and, due to interaction with beta-effect generates zonal jets. This system is archetypal for various geophysical systems including the general circulation and jet streams in the Earths atmosphere, the Antarctic Circumpolar Current or the areas in the vicinity of western boundary currents where baroclinic instability and multiple zonal jets are observed. The gradient of the surface elevation and the thickness of the upper layer are measured in the experiments using the Altimetric Imaging Velocim...

  5. Wind Diffusivity Current, METOP ASCAT, 0.25 degrees, Global, Near Real Time, Zonal

    National Oceanic and Atmospheric Administration, Department of Commerce — NOAA CoastWatch distributes near real time Ekman current (in zonal, meridional, and modulus sets) and Ekman upwelling data. This data begins with wind velocity...

  6. Wind Stress, QuikSCAT SeaWinds, 0.25 degrees, Global, Science Quality, Zonal

    National Oceanic and Atmospheric Administration, Department of Commerce — NOAA CoastWatch distributes science quality wind stress data in zonal, meridional, modulus, and wind stress curl sets. This data begins with wind velocity...

  7. HIRDLS/Aura Level 3 Water Vapor (H2O) Zonal Fourier Coefficients V007

    National Aeronautics and Space Administration — The "HIRDLS/Aura Level 3 Water Vapor (H2O) Zonal Fourier Coefficients" version 7 data product (H3ZFCH2O) contains the entire mission (~3 years) of HIRDLS data...

  8. HIRDLS/Aura Level 3 Dinitrogen Pentoxide (N2O5) Zonal Fourier Coefficients V007

    National Aeronautics and Space Administration — The "HIRDLS/Aura Level 3 Dinitrogen Pentoxide (N2O5) Zonal Fourier Coefficients" version 7 data product (H3ZFCN2O) contains the entire mission (~3 years) of HIRDLS...

  9. HIRDLS/Aura Level 3 Nitric Acid (HNO3) Zonal Fourier Coefficients V007

    National Aeronautics and Space Administration — The "HIRDLS/Aura Level 3 Nitric Acid (HNO3) Zonal Fourier Coefficients" version 7 data product (H3ZFCHNO3) contains the entire mission (~3 years) of HIRDLS data...

  10. HIRDLS/Aura Level 3 Chlorofluorocarbon-12 (CFC-12) Zonal Fourier Coefficients V007

    National Aeronautics and Space Administration — The "HIRDLS/Aura Level 3 Chlorofluorocarbon-12 (CFC-12) Zonal Fourier Coefficients" version 7 data product (H3ZFCCFC12) contains the entire mission (~3 years) of...