23 research outputs found

    Polar vortex formation in giant-planet atmospheres due to moist convection

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    A strong cyclonic vortex has been observed on each of Saturn’s poles, coincident with a local maximum in observed tropospheric temperature. Neptune also exhibits a relatively warm, although much more transient, region on its south pole. Whether similar features exist on Jupiter will be resolved by the 2016 Juno mission. Energetic, small-scale storm-like features that originate from the water-cloud level or lower have been observed on each of the giant planets and attributed to moist convection, suggesting that these storms play a significant role in global heat transfer from the hot interior to space. Nevertheless, the creation and maintenance of Saturn’s polar vortices, and their presence or absence on the other giant planets, are not understood. Here we use simulations with a shallow-water model to show that storm generation, driven by moist convection, can create a strong polar cyclone throughout the depth of a planet’s troposphere. We find that the type of shallow polar flow that occurs on a giant planet can be described by the size ratio of small eddies to the planetary radius and the energy density of its atmosphere due to latent heating from moist convection. We suggest that the observed difference in these parameters between Saturn and Jupiter may preclude a Jovian polar cyclone.National Science Foundation (U.S.). Graduate Research FellowshipNational Science Foundation (U.S.) (ATM-0850639)National Science Foundation (U.S.) (AGS-1032244)National Science Foundation (U.S.) (AGS-1136480)United States. Office of Naval Research (N00014-14-1-0062

    Electroconvulsive therapy and structural neuroplasticity in neocortical, limbic and paralimbic cortex.

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    Electroconvulsive therapy (ECT) is a highly effective and rapidly acting treatment for severe depression. To understand the biological bases of therapeutic response, we examined variations in cortical thickness from magnetic resonance imaging (MRI) data in 29 patients scanned at three time points during an ECT treatment index series and in 29 controls at two time points. Changes in thickness across time and with symptom improvement were evaluated at high spatial resolution across the cortex and within discrete cortical regions of interest. Patients showed increased thickness over the course of ECT in the bilateral anterior cingulate cortex (ACC), inferior and superior temporal, parahippocampal, entorhinal and fusiform cortex and in distributed prefrontal areas. No changes across time occurred in controls. In temporal and fusiform regions showing significant ECT effects, thickness differed between patients and controls at baseline and change in thickness related to therapeutic response in patients. In the ACC, these relationships occurred in treatment responders only, and thickness measured soon after treatment initiation predicted the overall ECT response. ECT leads to widespread neuroplasticity in neocortical, limbic and paralimbic regions and changes relate to the extent of antidepressant response. Variations in ACC thickness, which discriminate treatment responders and predict response early in the course of ECT, may represent a biomarker of overall clinical outcome. Because post-mortem studies show focal reductions in glial density and neuronal size in patients with severe depression, ECT-related increases in thickness may be attributable to neuroplastic processes affecting the size and/or density of neurons and glia and their connections

    Isolation, identification and evaluation of antimicrobial activity of streptomyces flavogriseus, strain actk2 from soil sample of Kodagu, Karnataka state (India)

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    Background: The search for novel antibiotics continues to be of immense importance in research programs around the world for pharmaceutical, industrial and agricultural applications. Filamentous soil bacteria, belonging to the Streptomyces genus, are widely used as an important biological tool for their ability to produce a wide range of novel secondary metabolites, such as ``antibiotics''. Objectives: The aim of the present study was to isolate and identify a strain of Streptomyces with high antibiotic production capability. Materials and Methods: The soil sample was collected randomly from the agricultural land of Kushalnagar Taluk of Kodagu district, Karnataka, India. The ACTK2 strain was isolated by serial dilution method and identified based on cultural, morphological, microscopic, biochemical and sequence analysis of 16S rRNA gene parameters. The isolated ACTK2 was analyzed for antimicrobial activities by perpendicular streak and disc diffusion methods, against the Gram-positive bacteria Staphylococcus aureus (MTCC 96), Bacillus subtilis (MTCC 121), Gram-negative Escherichia. coli (MTCC 729), Enterococcus aerogenes (MTCC 2829) and filamentous fungi (Trichoderma harizianum (MTCC6046), Fusarium proliferatum (MTCC 9375). Further, an antimicrobial metabolite from the ACTK2 strain was extracted by solvent extraction method, using n-butanol. The production of the antimicrobial compound by the ACTK2 strain was optimized by using different nutritional media and cultural conditions. Results: The strain Streptomyces flavogriseus designated as ACTK2 (Accession number KC990785) isolated from the soil sample of Kushalnagar Taluk, Kodagu, Karnataka, India, exhibited a broad spectrum of antimicrobial activity against test microorganisms. The optimum growth and antimicrobial compound production by strain ACTK2 was found to be a maximal pH 8, in the shaker incubator at 28 degrees C, for a period of 10 days. Conclusions: The crude n-butanol extract of the ACTK2 strain of S. flavogriseus showed a broad spectrum of antimicrobial activities against the test organisms and this opened further research investigations on purification and structural characterization of the active compounds from the crude extract

    The associations of mobile touch screen device use with musculoskeletal symptoms and exposures: A systematic review

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    Background: The use of mobile touch screen devices (MTSDs) has increased rapidly over the last decade, and there are concerns that their use may have negative musculoskeletal consequences; yet evidence on the association of MTSD use with musculoskeletal symptoms and exposures is currently dispersed. The aim of this study was to systematically review available literature on musculoskeletal symptoms and exposures associated with MTSD use. The synthesised information may facilitate wise use of MTSDs and may identify areas in need of further research. Methods: EMBASE, Medline, Scopus, PsycINFO and Proquest electronic databases were searched for articles published up to June 2016, using keywords describing MTSD, musculoskeletal symptoms (e.g. pain, discomfort) and musculoskeletal exposures (e.g. posture, muscle activity). Two reviewers independently screened the articles, extracted relevant data and assessed methodological quality of included studies. Due to heterogeneity in the studies, a meta-analysis was not possible and a structured narrative synthesis of the findings was undertaken. Results: A total of 9,908 articles were screened for eligibility with 45 articles finally included for review. Included articles were of cross-sectional, case-control or experimental laboratory study designs. No longitudinal studies were identified. Findings were presented and discussed in terms of the amount, features, tasks and positions of MTSD use and its association with musculoskeletal symptoms and musculoskeletal exposures. Conclusions: There is limited evidence that MTSD use, and various aspects of its use (i.e. amount of usage, features, tasks and positions) are associated with musculoskeletal symptoms and exposures. This is due to mainly low quality experimental and case-control laboratory studies, with few cross-sectional and no longitudinal studies. Further research is warranted in order to develop guidelines for wise use of MTSDs
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