112 research outputs found

    On the Radio Noises and Oscillations Caused by Fluorescent Lamps

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    The radio noises caused by fluorescent lamps were investigated in connection with high frequency oscillations in fluorescent lamps, and the mechanisms of oscillations were considered with some experimental results. Reignition oscillation, the wave form of which is irregular and consists of train of fine pulses, is sensitive to external heating of the filament and magnetic field near the cathode. Its frequency spectrum is nearly flat in broadcast band, and its noise level is 62 db (20W lamp) and 50 db (40W lamp) respectively in mean value of symetric quasi-peak voltage at 1MC, and is reduced by 30 db with 0.005 µPF capacitor conncted between lamp terminals. The twin oscillation, the waveform of which is regular and nearly sinusoidal, has the frequency spectrum which is similar to the resonance curve, and in many cases the peak of its spectrum is found in broadcast band. The high frequency oscillation is observed also in DC discharge, and its characteristics are just the same with those of the twin oscillation. The frequencies of these oscillations vary nearly in proportion to the square root of the lamp current, and are affected by interterminal capacitor. The cause of reignition oscillation is the fluctuation of ionization in increasing and decreasing period of space charge during transient time on reversing of the lamp current. The origin of twin oscillation is the oscillatory behavior of ionized medium with suitable accelerating field at the cathode surface, and for generation of the oscillation it is necessary that some conditions of the feedback from the boundary of the medium to the cathode are satisfied

    Use of Cervical Ultrasonography in Globus Sensation Investigation: A Retrospective Cohort Study

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    Background: A globus sensation is one of the most common complaints in otolaryngological practice. Patients with no associated abnormalities detected during the usual examinations performed in ENT clinics, are being diagnosed with globus sensation. Cervical ultrasonography is usually not performed in ENT clinics; however, it is useful in screening diseases of the subcutaneous tissue/organs, whose detection is not possible with the routine ENT examinations. The purpose of our study was to elucidate whether cervical ultrasound examination identifies abnormalities in patients with globus sensation. Methods: A single-centre retrospective cohort study. Cervical ultrasonographic examinations were performed on patients with globus sensation at the Department of Otolaryngology, Head and Neck Surgery of Tottori university hospital, a tertiary care centre, from January 2013 to September 2017. The subjects were 74 patients who complained of globus sensation with no abnormality in general otolaryngological examination including laryngoscopy. Results: Ultrasonography detected structural abnormalities in 60.8% of the patients with globus sensation: thyroid disorders in 41 patients, including: 35 patients with thyroid nodules, 4 patients with Hashimoto’s disease, 1 patient with Grave’s disease, and 1 patient with subacute thyroiditis; Sjögren syndrome in 2 patients; and cervical lipoma in 1 patient. Furthermore, 2 patients with thyroid disorders had concomitant esophageal cancer. Conclusion: Cervical ultrasonography identified thyroid disorders in patients with globus sensation, despite the normal ENT status. Therefore, it would be appropriate to adopt cervical ultrasonography as a routine examination at ENT clinics for patients with globus sensation

    Impact of Screening for Salivary Gland by Ultrasonography

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    Background: Ultrasonography is superior to other imaging modalities for detecting salivary gland diseases. However, there have been no reports of the results of salivary gland screening with ultrasonography. In this study, the salivary glands were also observed during thyroid ultrasonography to determine the degree of salivary gland abnormalities detected by ultrasonography. Methods: This study was conducted retrospectively using medical records. It assessed the association between the following abnormal findings detected during thyroid ultrasonography and their final diagnoses: atrophy/swelling, unclear demarcation from surrounding tissues, decreased salivary gland parenchyma echo level, heterogeneity of parenchyma, hypervascularity of salivary gland parenchyma, dilatation of the ducts, and a mass within the gland. Results: Of the 908 patients who underwent thyroid ultrasonography, salivary gland abnormalities were detected in 36 (4.0%) patients. Of the 36 patients with abnormal ultrasonographic findings, 22 underwent further examination. Of the 22 patients, 16 received definitive diagnoses of salivary gland diseases. Salivary gland disorders were considered to be absent in patients with only heterogeneity of the salivary glands observed on ultrasonography. Salivary gland disorders in all patients with further abnormal ultrasonographic findings such as atrophy/swelling, unclear boundary, or hypervascularity in addition to internal heterogeneity were confirmed by further blood examinations and imaging studies. We were able to detect autoimmune sialadenitis such as Sj ögren’s syndrome and IgG4-related sialadenitis by ultrasonography in patients without obvious symptoms. Conclusion: Salivary gland screening during thyroid ultrasonography revealed abnormal findings including Sjögren’s syndrome and IgG4-related sialadenitis in about 4% of the patients. Thus, ultrasonography may also be useful for early detection of autoimmune diseases of salivary glands

    Usefulness of a Novel Ultrasonographic Classification Based on Anechoic Area Patterns for Differentiating Warthin Tumors from Pleomorphic Adenomas of the Parotid Gland

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    [Background]Ultrasonographic homogeneity is an important differential finding between Warthin tumor and pleomorphic adenoma, two types of benign parotid gland tumors, with the former likely to be heterogeneous and the latter homogeneous. However, differences in the performance of ultrasound machines or the homogeneity cut-off level affect the judgment of ultrasonographic homogeneity. Therefore, in this study, we adopted a novel system for classifying the composition of tumors via ultrasonography, using anechoic area as a substitute for differences in homogeneity to differentiate between Warthin tumors and pleomorphic adenomas. [Methods]We evaluated 68 tumors that were histopathologically diagnosed as Warthin tumor or pleomorphic adenoma between July 2009 and November 2015. Ultrasonographic images of the tumors were evaluated on the basis of key differentiating features, including features on B-mode imaging and color Doppler imaging. Additionally, the tumors were classified into four groups based on anechoic area, and findings were compared between Warthin tumors and pleomorphic adenomas. [Results]While 38 of the tumors were pleomorphic adenomas, 30 were Warthin tumors. The sensitivity, specificity, positive predictive value, negative predictive value, and diagnostic accuracy for detection of Warthin tumors using our novel classification system were 73.3%, 76.3%, 71.0%, 78.4% and 75.0%, respectively. Compared to pleomorphic adenomas, Warthin tumors showed large or sponge-like anechoic areas, rich vascularization and an oval shape even at large tumor sizes, and the difference was significant. On defining Warthin tumor as a tumor demonstrating two or more of the findings noted above, the sensitivity, specificity, positive predictive value, negative predictive value and diagnostic accuracy for its detection were 73.3%, 84.2%, 78.6%, 80.0% and 79.4%, respectively. [Conclusion]Our novel classification system based on anechoic area patterns demonstrated by the tumors had high sensitivity, specificity and diagnostic accuracy for differentiating Warthin tumors from pleomorphic adenomas

    Localized Brain Activation Related to the Strength of Auditory Learning in a Parrot

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    Parrots and songbirds learn their vocalizations from a conspecific tutor, much like human infants acquire spoken language. Parrots can learn human words and it has been suggested that they can use them to communicate with humans. The caudomedial pallium in the parrot brain is homologous with that of songbirds, and analogous to the human auditory association cortex, involved in speech processing. Here we investigated neuronal activation, measured as expression of the protein product of the immediate early gene ZENK, in relation to auditory learning in the budgerigar (Melopsittacus undulatus), a parrot. Budgerigar males successfully learned to discriminate two Japanese words spoken by another male conspecific. Re-exposure to the two discriminanda led to increased neuronal activation in the caudomedial pallium, but not in the hippocampus, compared to untrained birds that were exposed to the same words, or were not exposed to words. Neuronal activation in the caudomedial pallium of the experimental birds was correlated significantly and positively with the percentage of correct responses in the discrimination task. These results suggest that in a parrot, the caudomedial pallium is involved in auditory learning. Thus, in parrots, songbirds and humans, analogous brain regions may contain the neural substrate for auditory learning and memory

    Spatial correlation between submillimetre and Lyman-alpha galaxies in the SSA 22 protocluster

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    Lyman-alpha emitters are thought to be young, low-mass galaxies with ages of ~10^8 yr. An overdensity of them in one region of the sky (the SSA 22 field) traces out a filamentary structure in the early Universe at a redshift of z = 3.1 (equivalent to 15 per cent of the age of the Universe) and is believed to mark a forming protocluster. Galaxies that are bright at (sub)millimetre wavelengths are undergoing violent episodes of star formation, and there is evidence that they are preferentially associated with high-redshift radio galaxies, so the question of whether they are also associated with the most significant large-scale structure growing at high redshift (as outlined by Lyman-alpha emitters) naturally arises. Here we report an imaging survey of 1,100-um emission in the SSA 22 region. We find an enhancement of submillimetre galaxies near the core of the protocluster, and a large-scale correlation between the submillimetre galaxies and the low-mass Lyman-alpha emitters, suggesting synchronous formation of the two very different types of star-forming galaxy within the same structure at high redshift. These results are in general agreement with our understanding of the formation of cosmic structure.Comment: Published in Nature (7th May 2009 issue). The astro-ph paper includes the main text (10 pages, 2 figures, 1 table) and supplementary material (6 pages, 4 figures, 1 table

    SXDF-ALMA 2 Arcmin^2 Deep Survey: Resolving and Characterizing the Infrared Extragalactic Background Light Down to 0.5 mJy

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    We present a multi-wavelength analysis of five submillimeter sources (S_1.1mm = 0.54-2.02 mJy) that were detected during our 1.1-mm-deep continuum survey in the SXDF-UDS-CANDELS field (2 arcmin^2, 1sigma = 0.055 mJy beam^-1) using the Atacama Large Millimeter/submillimeter Array (ALMA). The two brightest sources correspond to a known single-dish (AzTEC) selected bright submillimeter galaxy (SMG), whereas the remaining three are faint SMGs newly uncovered by ALMA. If we exclude the two brightest sources, the contribution of the ALMA-detected faint SMGs to the infrared extragalactic background light is estimated to be ~ 4.1^{+5.4}_{-3.0} Jy deg^{-2}, which corresponds to ~ 16^{+22}_{-12}% of the infrared extragalactic background light. This suggests that their contribution to the infrared extragalactic background light is as large as that of bright SMGs. We identified multi-wavelength counterparts of the five ALMA sources. One of the sources (SXDF-ALMA3) is extremely faint in the optical to near-infrared region despite its infrared luminosity (L_IR ~ 1e12 L_sun or SFR ~ 100 M_sun yr^{-1}). By fitting the spectral energy distributions (SEDs) at the optical-to-near-infrared wavelengths of the remaining four ALMA sources, we obtained the photometric redshifts (z_photo) and stellar masses (M_*): z_photo ~ 1.3-2.5, M_* ~ (3.5-9.5)e10 M_sun. We also derived their star formation rates (SFRs) and specific SFRs (sSFRs) as ~ 30-200 M_sun yr^{-1} and ~ 0.8-2 Gyr^{-1}, respectively. These values imply that they are main-sequence star-forming galaxies.Comment: PASJ accepted, 15 pages, 6 figures, 2 table

    A gravitationally unstable gas disk of a starburst galaxy 12 billion years ago

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    Submillimeter bright galaxies in the early Universe are vigorously forming stars at ~1000 times higher rate than the Milky Way. A large fraction of stars is formed in the central 1 kiloparsec region, that is comparable in size to massive, quiescent galaxies found at the peak of the cosmic star formation history, and eventually the core of giant elliptical galaxies in the present-day Universe. However, the physical and kinematic properties inside a compact starburst core are poorly understood because dissecting it requires angular resolution even higher than the Hubble Space Telescope can offer. Here we report 550 parsec-resolution observations of gas and dust in the brightest unlensed submillimeter galaxy at z=4.3. We map out for the first time the spatial and kinematic structure of molecular gas inside the heavily dust-obscured core. The gas distribution is clumpy while the underlying disk is rotation-supported. Exploiting the high-quality map of molecular gas mass surface density, we find a strong evidence that the starburst disk is gravitationally unstable, implying that the self-gravity of gas overcomes the differential rotation and the internal pressure by stellar radiation feedback. The observed molecular gas would be consumed by star formation in a timescale of 100 million years, that is comparable to those in merging starburst galaxies. Our results suggest that the most extreme starburst in the early Universe originates from efficient star formation due to a gravitational instability in the central 2 kpc region.Comment: Published in Nature on August 30 2018 (submitted version

    The effect of a prostaglandin E-1 derivative on the symptoms and quality of life of patients with lumbar spinal stenosis

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    Quality of life (QOL) is a concern for patients with lumbar spinal stenosis (LSS). In this study, QOL was examined using the 5-item EuroQol (EQ-5D). QOL and activities of daily living (ADL) were surveyed for 91 patients who visited 18 medical institutions in our prefecture and were diagnosed with LSS-associated intermittent claudication. A second survey was performed after a parts per thousand yen6 weeks for 79 of the subjects to evaluate therapy with limaprost (an oral prostaglandin E1 derivative) or etodolac (an NSAID). Symptoms, maximum walking time, QOL, ADL items, and relationships among these variables were investigated for all 91 patients. Leg pain, leg numbness, and low back pain while walking were surveyed by use of VAS scores (0-100). Leg pain, leg numbness, and low back pain while walking (VAS a parts per thousand yen25) were present in 83.5, 62.6, and 54.9 % of the patients in the first survey, and approximately half of the patients had a maximum walking time 30 min, showing that maximum walking time affected health-related QOL. Of the 79 patients who completed the second survey, 56 had taken limaprost and 23 (control group) had received etodolac. Limaprost improved possible walking time, reduced ADL interference, and significantly increased the EQ-5D utility score, whereas no significant changes occurred in the control group. Maximum walking time was prolonged by a parts per thousand yen10 min and the EQ-5D utility value was improved by a parts per thousand yen0.1 points in significantly more patients in the limaprost group than in the control group. According to the findings of this survey, at an average of 8 weeks after administration limaprost improved symptoms, QOL, and ADL in LSS patients whereas treatment with an NSAID reduced pain but did not have any other effects.ArticleJOURNAL OF ORTHOPAEDIC SCIENCE. 18(2):208-215 (2013)journal articl
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