135 research outputs found

    Deciphering Patterns and Drivers of Heat and Carbon Storage in the Southern Ocean

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    The storage of anomalous heat and carbon in the Southern Ocean in response to increasing greenhouse gases greatly mitigates atmospheric warming and exerts a large impact on the marine ecosystem. However, the mechanisms driving the ocean storage patterns are uncertain. Here using recent hydrographic observations, we compare for the first time the spatial patterns of heat and carbon storage, which show substantial differences in the Southern Ocean, in contrast with the conventional view of simple passive subduction into the thermocline. Using an eddy‐rich global climate model, we demonstrate that redistribution of the preindustrial temperature field is the dominant control on the heat storage pattern, whereas carbon storage largely results from passive transport of anthropogenic carbon uptake at the surface. Lastly, this study highlights the importance of realistic representation of wind and surface buoyancy flux in climate models to improve future projection of circulation change and thus heat and carbon storage.This work was sponsored by Southern Ocean Carbon and Climate Observations and Modeling Project under the NSF Award PLR‐1425989 with additional support from NOAA and NASA. A. K. M. was supported by Australian Research Council Fellowship DE170100184. C. O. D. was supported by NASA Award NNX14AL40G and by the Princeton Environmental Institute Grand Challenge initiative

    Logistic Regression Analysis of Factors Influencing the Effectiveness of Intensive Sound Masking Therapy in Patients with Tinnitus

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    Objectives: To investigate factors influencing the effectiveness intensive sound masking therapy on tinnitus using Logistic Regression Analysis. Design: The study used a retrospective cross-section analysis. Participants: 102 patients with tinnitus were recruited at the Sun Yat-sen Memorial Hospital of Sun Yat-sen University, China. Intervention: Intensive sound masking therapy was used as an intervention approach for patients with tinnitus. Primary and secondary outcome measures: participants underwent audiological investigations and tinnitus pitch and loudness matching measurements, followed by intensive sound masking therapy. The Tinnitus Handicap Inventory (THI) was used as the outcome measure pre- and post-treatment. Multivariate logistic regression was performed to investigate the association of demographic and audiological factors with effective therapy. Results: According to the THI score changes pre-and post-sound masking intervention, fifty-one participants were categorised into an effective group, the remaining 51 participants were placed in a non-effective group. Those in the effective group were significantly younger than those in the non-effective group (p=0.012). Significantly more participants had flat audiogram configurations in the effective group (p=0.04). Multivariable logistic regression analysis showed that age (OR=0.96, 95% CI: 0.93, 0.99, p=0.007), audiometric configuration (p=0.027) and THI score pre-treatment (OR=1.04, 95% CI: 1.02, 1.07, p<0.001) were significantly associated with therapeutic effectiveness. Further analysis showed that patients with flat audiometric configurations were 5.45 times more likely to respond to intervention than those with high-frequency steeply sloping audiograms (OR=5.45, 95% CI: 1.67, 17.86, p=0.005). Conclusion: Audiometric configuration, age and THI scores appear to be predictive for the effectiveness of sound masking treatment. Gender, tinnitus characteristics and hearing threshold measures seem not to be related to treatment effectiveness. Further randomized control study is needed to provide further evidence of the effectiveness of prognostic factors in tinnitus interventions

    The effect of symmetrical and asymmetrical hearing impairment on the music quality perception

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    The purpose of this study was to investigate the effect of symmetrical, asymmetrical and unilateral hearing impairment on music quality perception. Six validated music pieces in the categories of classical music, folk music and pop music were used to assess music quality in terms of its ‘pleasantness’, ‘naturalness’, ‘fullness’, ‘roughness’ and ‘sharpness’. 58 participants with sensorineural hearing loss [20 with unilateral hearing loss (UHL), 20 with bilateral symmetrical hearing loss (BSHL) and 18 with bilateral asymmetrical hearing loss (BAHL)] and 29 normal hearing (NH) subjects participated in the present study. Hearing impaired (HI) participants had greater difficulty in overall music quality perception than NH participants. Participants with BSHL rated music pleasantness and naturalness to be higher than participants with BAHL. Moreover, the hearing thresholds of the better ears from BSHL and BAHL participants as well as the hearing thresholds of the worse ears from BSHL participants were negatively correlated to the pleasantness and naturalness perception. HI participants rated the familiar music pieces higher than unfamiliar music pieces in the three music categories. Music quality perception in participants with hearing impairment appeared to be affected by symmetry of hearing loss, degree of hearing loss and music familiarity when they were assessed using the music quality rating test (MQRT). This indicates that binaural symmetrical hearing is important to achieve a high level of music quality perception in HI listeners. This emphasizes the importance of provision of bilateral hearing assistive devices for people with asymmetrical hearing impairment

    Deviant Dynamics of Resting State Electroencephalogram Microstate in Patients With Subjective Tinnitus

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    Given the importance of central reorganization and tinnitus, we undertook the current study to investigate changes to electroencephalogram (EEG) microstates and their association with the clinical symptoms in tinnitus. High-density (128 channel) EEG was used to explore changes in microstate features in 15 subjects with subjective tinnitus and 17 age-matched controls. Correlations between microstate parameters and subjective tinnitus symptoms were also analyzed. An increased presence of class A microstate and decreased presence of class D microstate were found in coverage and lifespan of microstate parameters in the tinnitus patients. Syntax analysis also demonstrated an aberrant pattern of activity, with reduced transitions from class D to class B in tinnitus patients. Moreover, a significant positive correlation of tinnitus loudness with increased lifespan of microstate class C was found. Significant differences in temporal characteristics and syntax of the EEG microstate classes were found at rest between tinnitus patients and the healthy subjects. Our study indicates that EEG microstates may provide a possible valuable method to study large-scale brain networks, which may in turn be beneficial to investigation of the neurophysiological mechanisms behind tinnitus

    Sirtuin 1 and Autophagy Attenuate Cisplatin-Induced Hair Cell Death in the Mouse Cochlea and Zebrafish Lateral Line

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    Cisplatin-induced ototoxicity is one of the major adverse effects in cisplatin chemotherapy, and hearing protective approaches are unavailable in clinical practice. Recent work unveiled a critical role of autophagy in cell survival in various types of hearing loss. Since the excessive activation of autophagy can contribute to apoptotic cell death, whether the activation of autophagy increases or decreases the rate of cell death in CDDP ototoxicity is still being debated. In this study, we showed that CDDP induced activation of autophagy in the auditory cell HEI-OC1 at the early stage. We then used rapamycin, an autophagy activator, to increase the autophagy activity, and found that the cell death significantly decreased after CDDP injury. In contrast, treatment with the autophagy inhibitor 3-methyladenine (3-MA) significantly increased cell death. In accordance with in vitro results, rapamycin alleviated CDDP-induced death of hair cells in zebrafish lateral line and cochlear hair cells in mice. Notably, we found that CDDP-induced increase of Sirtuin 1 (SIRT1) in the HEI-OC1 cells modulated the autophagy function. The specific SIRT1 activator SRT1720 could successfully protect against CDDP-induced cell loss in HEI-OC1 cells, zebrafish lateral line, and mice cochlea. These findings suggest that SIRT1 and autophagy activation can be suggested as potential therapeutic strategies for the treatment of CDDP-induced ototoxicity

    The Deep Ocean's Carbon Exhaust.

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    Promotion of transition metal oxides on the NH3-SCR performance of ZrO2-CeO2 catalyst

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    Chromium oxide and manganese oxide promoted ZrO2-CeO2 catalysts were prepared by a homogeneous precipitation method for the selective catalytic reduction of NOx with NH3. A series of characterization including X-ray diffraction (XRD), high-resolution transmission electron microscope (HR-TEM), Brunauer-Emmett-Teller (BET) surface area analysis, H-2 temperature-programmed reduction (H-2-TPR), and X-ray photoelectron spectroscopy (XPS) were used to evaluate the influence of the physicochemical properties on NH3-SCR activity. Cr-Zr-Ce and Mn-Zr-Ce catalysts are much more active than ZrO2-CeO2 binary oxide for the low temperature NH3-SCR, mainly because of the high specific surface area, more surface oxygen species, improved reducibility derived from synergistic effect among different elements. Mn-Zr-Ce catalyst exhibited high tolerance to SO2 and H2O. Cr-Zr-Ce mixed oxide exhibited&gt; 80% NOx conversion at a wide temperature window of 100 degrees C-300 degrees C. In situ DRIFT studies showed that the addition of Cr is beneficial to the formation of Bronsted acid sites and prevents the formation of stable nitrate species because of the presence of Cr6+. The present mixed oxide can be a candidate for the low temperature abatement of NOx. (C) Higher Education Press and Springer-Verlag Berlin Heidelberg 2017</p

    Promotion of transition metal oxides on the NH_3-SCR performance of ZrO_2-CeO_2 catalyst

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    Chromium oxide and manganese oxide promoted ZrO_2-CeO_2 catalysts were prepared by a homogeneous precipitation method for the selective catalytic reduction of NO_x with NH_3. A series of characterization including X-ray diffraction (XRD), high-resolution transmission electron microscope (HR-TEM),Brunauer-Emmett-Teller (BET) surface area analysis,H_2 temperature-programmed reduction (H_2-TPR),and X-ray photoelectron spectroscopy (XPS) were used to evaluate the influence of the physicochemical properties on NH_3-SCR activity. Cr-Zr-Ce and Mn-Zr-Ce catalysts are much more active than ZrO_2-CeO_2 binary oxide for the low temperature NH_3-SCR, mainly because of the high specific surface area, more surface oxygen species,improved reducibility derived from synergistic effect among different elements. Mn-Zr-Ce catalyst exhibited high tolerance to SO_2 and H_2O. Cr-Zr-Ce mixed oxide exhibited >80% NO_x conversion at a wide temperature window of 100°C-300°C. In situ DRIFT studies showed that the addition of Cr is beneficial to the formation of Bronsted acid sites and prevents the formation of stable nitrate species because of the presence of Cr~(6+). The present mixed oxide can be a candidate for the low temperature abatement of NO_x
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