280 research outputs found

    Arduino based configurable LED stimulus design for multi-frequency SSVEP-BCI

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    Steady state visually evoked potentials (SSVEP) are extensively used in the research of brain-computer interface (BCI) and require a configurable light source flashing at different frequencies. Precise control of simultaneous multiple frequencies are essential for SSVEP studies and also for reducing the visual fatigue. Instead of LCD based stimulus which requires more resources and power, light emitting diodes (LEDs) are used as a light source as they are energy efficient, consume lower power, have higher contrast, less tiring visually, have multi-chromatic function and supports wider frequency ranges. In this paper, we propose a visual stimulator using off-shelf components to build a simple and yet customisable LED stimulus for testing the performance and qualitative user comfort using SSVEP electroencephalogram (EEG) data

    Quantification of SSVEP responses using multi-chromatic LED stimuli: Analysis on colour, orientation and frequency

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    Most LED visual stimulators used in steady state visual evoked potential (SSVEP) brain-computer interface (BCI) use single LED sources to elicit SSVEP responses. In this study, we tested the hypothesis that different orientations would have different responses in different participants and aimed to develop a portable LED based stimulus design which consists of a small number of RGB LEDs arranged in a line which can be oriented horizontally or vertically. The colour and frequency of the flicker were controlled by a portable microcontroller platform. The study investigated the performance of the SSVEP from five participants when the LED stimulus was displayed vertically and horizontally for a period of 30 seconds. The frequency range used was from 7 Hz to 11 Hz with three primary colours: red, green and blue in both orientations. Furthermore, we also compared the effect of vertical and horizontal orientations using four different frequencies and three colours to test visual fatigue reduction. The results of the analysis using band-pass filtering and Fast Fourier Transform showed that the green horizontal LED stimulus orientation gave the highest response and viewing comfort in all the participants rather than the vertical orientation

    A prospective study of non-malignant lesions of larynx.

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    Larynx is an important organ of the body. The primary function of the larynx is to provide protection to the lower airway. It secondarily evolved to serve as a vocal generator of sound. The larynx produces sound which is the major medium of communication. Voice helps in expressing emotions even without the help of language. It expresses the mood and attitude. It is the tone of voice which gives meaning, while in verbal use, the quality of voice is very significant specially for professional voice users like singers. The spectrum of voice disorders is very wide and its impact on different individuals also varies. Benign lesions of the larynx include neoplastic and nonneoplastic lesions. They are broadly classified together because clinically they behave similarly. Any lesion affecting the larynx will cause a range of voice disorder. Voice disorders caused by benign lesions are correctable by surgery and voice rest and voice therapy in few cases. In the present study, 70 cases of benign lesions of the larynx were studied. All lesions presented with some kind of voice disorder. 90% of the cases presented with hoarseness, while another 42% had vocal fatigue. 42% had reduced vocal range and 4.4% had aphonia. Amongst the causative factors of vocal nodule, vocal abuse was a common constant cause. 57% of the affected patients were smokers while both the cases of vocal granuloma had a previous history of endotracheal intubation. The sex distribution of different lesions were different. Maximum patients presented were in the third decade (26.8). This was followed closely by patients in the second, fourth and fifth decade. Video laryngoscopy was the most specific modality of investigation. Computed Tomography, Magnetic Resonance Imaging and Electroglottogram were not considered necessary. Microlaryngeal excision was done for majority of the cases followed by voice rest and anti reflux medicines in some cases. Results were very good thereby saving substantial number of man days

    OPTIMIZATION OF CULTURAL PARAMETERS FOR THE PRODUCTION OF ANTIMICROBIAL COMPOUND FROM ENTEROCOCCUS FAECIUM CST-1 (MCC-2729)

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    Objective: To improve the productivity of antibacterial compounds of Eenterococcus feacium CST-1 by optimizing its nutrient and physical factors and screened for its antimicrobial activity by agar well diffusion method. Methods: In order to improve its efficiency, the effects of medium components carbon and nitrogen sources, temperature, pH, agitation, incubation time, were optimized and its productivity was determined by agar well diffusion method against four bacterial strains obtained from MTCC, Chandigarh, India namely Bacillus subtilis, E. coli, Psudomonas aeruginosa, Staphylococcus aureus,. Results: The bacterial inhibition rate was more in the optimized medium composition (g/100 ml), containing tryptone 1.5, dextrose 3.0 and incubation time for 76 hrs, temperature 35±2 °C and pH 6.5. Compared to basal medium the optimized medium shown about 1.2 fold increased in the zone of inhibition by Enterococcus feacium CST-1. Conclusion: The results from this study confirmed that the antibacterial substances produced by Eenterococcus feacium CST-1 were found to be more effective after its optimization

    Rate-dependence of the compressive and tensile strength of granites

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    The strength and rupture of geomaterials are integral to subsurface engineering practices, such as those required to optimise geothermal energy extraction. Of particular importance is the time- and strain-rate-dependence of material strength, which dictates the energy released upon failure, and impacts the magnitude of induced seismicity, fracture architecture and thus hydraulic conductivity and system permeability. Here, we performed a series of uniaxial compression and Brazilian tensile strength measurements at a range of deformation rates in order to constrain the impact of strain rate on the strength of G603 granite. The dense, low permeability, medium-grained granites were mechanically tested at 4 strain rates (or diametric equivalent strain rates in the case of Brazilian tests) from 10−5 to 10−2 s−1, such that sample failure was achieved in anything from below 1s at the fastest rate in tension, to over 1000s at the slowest rate in compression. The applied rates encompassed those recommended by ISRM and ASTM material testing standards for compressive and Brazilian tensile testing. We found a significant rate strengthening effect, whereby compressive and tensile strength both increased by approximately 35 % across the 4 orders of magnitude of strain rate tested. We found that the static Young's modulus remained relatively constant across this range of deformation rates, however variability was reduced at faster rates, owing to the reduced time for equilibration of the system to imposed stresses. The lower strength at slower strain rates causes smaller stress drops, indicating that rocks driven to compressive and tensile failure at slower rates release less energy upon failure. Such constraints of the strain-rate-dependence of material strength, in contrast to the use of standardised material characteristics conventionally used in Engineering Geology applications, will prove useful as we develop increasingly sophisticated strategies such as cyclic soft stimulation to access resources using less energy, whilst reducing environmental risk and producing less waste.</p

    Rate-dependence of the compressive and tensile strength of granites

    Get PDF
    The strength and rupture of geomaterials are integral to subsurface engineering practices, such as those required to optimise geothermal energy extraction. Of particular importance is the time- and strain-rate-dependence of material strength, which dictates the energy released upon failure, and impacts the magnitude of induced seismicity, fracture architecture and thus hydraulic conductivity and system permeability. Here, we performed a series of uniaxial compression and Brazilian tensile strength measurements at a range of deformation rates in order to constrain the impact of strain rate on the strength of G603 granite. The dense, low permeability, medium-grained granites were mechanically tested at 4 strain rates (or diametric equivalent strain rates in the case of Brazilian tests) from 10−5 to 10−2 s−1, such that sample failure was achieved in anything from below 1s at the fastest rate in tension, to over 1000s at the slowest rate in compression. The applied rates encompassed those recommended by ISRM and ASTM material testing standards for compressive and Brazilian tensile testing. We found a significant rate strengthening effect, whereby compressive and tensile strength both increased by approximately 35 % across the 4 orders of magnitude of strain rate tested. We found that the static Young's modulus remained relatively constant across this range of deformation rates, however variability was reduced at faster rates, owing to the reduced time for equilibration of the system to imposed stresses. The lower strength at slower strain rates causes smaller stress drops, indicating that rocks driven to compressive and tensile failure at slower rates release less energy upon failure. Such constraints of the strain-rate-dependence of material strength, in contrast to the use of standardised material characteristics conventionally used in Engineering Geology applications, will prove useful as we develop increasingly sophisticated strategies such as cyclic soft stimulation to access resources using less energy, whilst reducing environmental risk and producing less waste

    Caregiver Behavior Change for Child Survival and Development in Low- and Middle-Income Countries: An Examination of the Evidence

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    In June of 2012, representatives from more than 80 countries promulgated a Child Survival Call to Action, which called for reducing child mortality to 20 or fewer child deaths per 1,000 live births in every country by 2035. To address the problem of ending preventable child deaths, the U.S. Agency for International Development and the United Nations Children’s Fund convened, on June 3–4, 2013, an Evidence Summit on Enhancing Child Survival and Development in Lower- and Middle-Income Countries by Achieving Population-Level Behavior Change. Six evidence review teams were established on different topics related to child survival and healthy development to identify the relevant evidence-based interventions and to prepare reports. This article was developed by the evidence review team responsible for identifying the research literature on caregiver change for child survival and development. This article is organized into childhood developmental periods and cross-cutting issues that affect child survival and healthy early development across all these periods. On the basis of this review, the authors present evidence-based recommendations for programs focused on caregivers to increase child survival and promote healthy development. Last, promising directions for future research to change caregivers’ behaviors are given

    Realising the health and wellbeing of adolescents

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    Adolescence is a critical stage of life characterised by rapid biological, emotional, and social development. It is during this time that every person develops the capabilities required for a productive, healthy, and satisfying life. In order to make a healthy transition into adulthood, adolescents need to have access to health education, including education on sexuality1; quality health services, including sexual and reproductive; and a supportive environment both at home and in communities and countries.The global community increasingly recognises these vital needs of adolescents, and there is an emerging consensus that investing intensively in adolescents’ health and development is not only key to improving their survival and wellbeing but critical for the success of the post-2015 development agenda.2 The suggested inclusion of adolescent health in the United Nations secretary general’s Global Strategy for Women’s and Children’s Health is an expression of this growing awareness and represents an unprecedented opportunity to place adolescents on the political map beyond 2015. Ensuring that every adolescent has the knowledge, skills, and opportunities for a healthy, productive life and enjoyment of all human rights3 is essential for achieving improved health, social justice, gender equality, and other development goals.We argue that the priority in the revised Every Women Every Child Global Strategy needs to be giving adolescents a voice, expanding their choices and control over their bodies, and enabling them to develop the capabilities required for a productive, healthy, and satisfying life. We call for a global, participatory movement to improve the health of the world’s adolescents as part of a broader agenda to improve their wellbeing and uphold their rights
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