596 research outputs found

    Arachnoid Cyst Presenting With Sudden Hearing Loss

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    Arachnoid cysts can occur at different intracranial sites, including the cerebellopontine angle (CPA). They often occur in childhood, in the posterior fossa. They may present with symptoms such as dizziness, tinnitus and hearing loss, or they may be asymptomatic. Presentation with sudden deafness is very rare. We report the unusual presentation of a 67-year-old male with CPA arachnoid cyst and the complaint of sudden-onset deafness. In this case, the cystic lesion at the CPA was found by magnetic resonance imaging of the brain. Pathology after retromastoid suboccipital craniotomy confirmed an arachnoid cyst. The treatment of this patient is discussed and the possible causes of CPA arachnoid cyst are briefly reviewed

    Determinants and Impacts of the Relative Use of Depository Receipts and Euro Convertible Bonds by High-tech Corporations: An Empirical Study

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    This paper adopts Taiwan's high-tech companies as the sample to address and examine four new determinants of various foreign financing instruments and test their impacts on the issuing firms. Our empirical findings are consistent with the following notions. First, the firms with higher foreign holding and foreign investment will be likely to adopt foreign financing policy. Moreover, the firms with higher stock dividend payment in Taiwan will adopt both of ECB (Euro convertible bond) and DR (depository receipt). Firm managers with better education background will prefer DR. Second, the use of DR can effectively decrease the volatility of stock returns but also pronounce a negative influence on the mean of stock returns. In contrast, the use of ECB can effectively increase the mean but can not significantly decrease the volatility.

    Which Type Of Work-Study Experience Is More Beneficial?: Perceptions Of Taiwanese College Students

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    The rapidly increase of tuition and the reduced financial support from government and families have forced many more students to take part-time jobs, however, different jobs might bear different benefits. The main purpose of this study were to identify the major benefits of part-time jobs or work-study experiences performed by college students, and to calculate the relative weight of each benefits perceived by students, and finally, to determine the most appropriate type of job for college students. A self-developed questionnaire is administered to 250 students from three universities. The results of this study not only help students to select the most appropriate types of job for a given purpose, but also provide school administrators with a guide to develop their student part-time job policies

    A novel test of gravity via black hole eikonal correspondence

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    When adopted in black hole spacetimes, geometric-optics approximations imply a mapping between the quasinormal mode (QNM) spectrum of black holes in the eikonal limit and black hole images. In particular, the real part and the imaginary part of eikonal QNM frequencies are associated with the apparent size and the detailed structure of the ring images, respectively. This correspondence could be violated when going beyond general relativity. We propose a novel method to test the eikonal correspondence via the comparison of two sets of observables from a nonrotating black hole, one extracted from QNM spectra and the other from the lensed photon rings on the image plane. Specifically, the photon ring observables robustly capture the information of the black hole spacetime itself regardless of the surrounding emission models. Therefore, the proposed test of eikonal correspondence can be validated in quite broad scenarios.Comment: 9 pages, 2 figures. Matching published versio

    Carcinoma ex pleomorphic adenoma of soft palate with cavernous sinus invasion

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    <p>Abstract</p> <p>Background</p> <p>Carcinoma ex pleomorphic adenoma (CXPA) is an aggressive salivary gland malignancy and rare in minor salivary gland. A soft palate CXPA initially presenting as direct cavernous sinus (CS) invasion is very rare.</p> <p>Case Presentation</p> <p>A 60-year-old male had a 3-month history of a small soft palatal mass with progressing left cheek numbness, proptosis, and disturbed vision. Biopsy of soft palatal tumor showed pleomorphic adenoma. Magnetic resonance imaging showed a tumor involving left maxilla, and extended from pterygopalatine fossa, inferior orbital fissure to CS. Excision of tumor revealed CXPA. Adjuvant concomitant chemo-radiation therapy (CCRT) was given. The tumor recurred 5 months later in left CS which was re-treated with CCRT. The disease status was stable at 2 years after the diagnosis of CXPA.</p> <p>Conclusion</p> <p>We present this case to emphasize that patients with symptoms such as facial numbness, proptosis and disturbed vision should be carefully investigated for lesions invading CS by perineural spread.</p

    Optimization Study of Small-Scale Solar Membrane Distillation Desalination Systems (s-SMDDS)

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    [[abstract]]Membrane distillation (MD), which can utilize low-grade thermal energy, has been extensively studied for desalination. By incorporating solar thermal energy, the solar membrane distillation desalination system (SMDDS) is a potential technology for resolving energy and water resource problems. Small-scale SMDDS (s-SMDDS) is an attractive and viable option for the production of fresh water for small communities in remote arid areas. The minimum cost design and operation of s-SMDDS are determined by a systematic method, which involves a pseudo-steady-state approach for equipment sizing and dynamic optimization using overall system mathematical models. Two s-SMDDS employing an air gap membrane distillation module with membrane areas of 11.5 m2 and 23 m2 are analyzed. The lowest water production costs are 5.92/m3and5.92/m3 and 5.16/m3 for water production rates of 500 kg/day and 1000 kg/day, respectively. For these two optimal cases, the performance ratios are 0.85 and 0.91; the recovery ratios are 4.07% and 4.57%. The effect of membrane characteristics on the production cost is investigated. For the commercial membrane employed in this study, the increase of the membrane mass transfer coefficient up to two times is beneficial for cost reduction.[[notice]]補正完畢[[incitationindex]]SCI[[incitationindex]]EI[[booktype]]電子

    PEDOT:PSS/Graphene Nanocomposite Hole-Injection Layer in Polymer Light-Emitting Diodes

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    We report on effects of doping graphene in poly(3,4-ethylenedioxythiophene): poly(styrene sulfonate), PEDOT:PSS, as a PEDOT:PSS/graphene nanocomposite hole injection layer on the performance enhancement of polymer light-emitting diodes (PLEDs). Graphene oxides were first synthesized and then mixed in the PEDOT:PSS solution with specifically various amounts. Graphenes were reduced in the PEDOT:PSS matrix through thermal reduction. PLED devices with hole-injection nanocomposite layer containing particular doping concentration were fabricated, and the influence of doping concentration on device performance was examined by systematically characterizations of various device properties. Through the graphene doping, the resistance in the hole-injection layer and the turn-on voltage could be effectively reduced that benefited the injection and transport of holes and resulted in a higher overall efficiency. The conductivity of the hole-injection layer was monotonically increased with the increase of doping concentration, performance indices from various aspects, however, did not show the same dependence because faster injected holes might alter not only the balance of holes and electrons but also their combination locations in the light-emitting layer. Results show that optimal doping concentration was the case with 0.03 wt% of graphene oxide

    Real-Time Vehicle Routing for Repairing Damaged Infrastructures Due to Natural Disasters

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    We address the task of repairing damaged infrastructures as a series of multidepot vehicle-routing problems with time windows in a time-rolling frame. The network size of the tackled problems changes from time to time, as new disaster nodes will be added to and serviced disaster nodes will be deleted from the current network. In addition, an inaccessible disaster node would become accessible when one of its adjacent disaster nodes has been repaired. By the “take-and-conquer” strategy, the repair sequence of the disaster nodes in the affected area can be suitably scheduled. Thirteen instances were tested with our proposed heuristic, that is, Chen et al.'s approach. For comparison, Hsueh et al.'s approach (2008) with necessary modification was also tested. The results show that Chen et al.'s approach performs slightly better for larger size networks in terms of objective value

    Strong light confinement in rod-connected diamond photonic crystals

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    We show that it is possible to confine light in a volume of order 10−3 cubic wavelengths using only dielectric material. Low-index (air) cavities are simulated in high-index rod-connected diamond photonic crystals. These cavities show long storage times (Q -factors >106) even at the lowest volumes. Fabrication of such structures could open a new field of photon-level interactions
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